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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" | |
a542ad1b | 25 | |
8da6d581 JS |
26 | /* |
27 | * this structure records all encountered refs on the way up to the root | |
28 | */ | |
29 | struct __prelim_ref { | |
30 | struct list_head list; | |
31 | u64 root_id; | |
32 | struct btrfs_key key; | |
33 | int level; | |
34 | int count; | |
35 | u64 parent; | |
36 | u64 wanted_disk_byte; | |
37 | }; | |
38 | ||
39 | static int __add_prelim_ref(struct list_head *head, u64 root_id, | |
40 | struct btrfs_key *key, int level, u64 parent, | |
41 | u64 wanted_disk_byte, int count) | |
42 | { | |
43 | struct __prelim_ref *ref; | |
44 | ||
45 | /* in case we're adding delayed refs, we're holding the refs spinlock */ | |
46 | ref = kmalloc(sizeof(*ref), GFP_ATOMIC); | |
47 | if (!ref) | |
48 | return -ENOMEM; | |
49 | ||
50 | ref->root_id = root_id; | |
51 | if (key) | |
52 | ref->key = *key; | |
53 | else | |
54 | memset(&ref->key, 0, sizeof(ref->key)); | |
55 | ||
56 | ref->level = level; | |
57 | ref->count = count; | |
58 | ref->parent = parent; | |
59 | ref->wanted_disk_byte = wanted_disk_byte; | |
60 | list_add_tail(&ref->list, head); | |
61 | ||
62 | return 0; | |
63 | } | |
64 | ||
65 | static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, | |
66 | struct ulist *parents, | |
67 | struct extent_buffer *eb, int level, | |
68 | u64 wanted_objectid, u64 wanted_disk_byte) | |
69 | { | |
70 | int ret; | |
71 | int slot; | |
72 | struct btrfs_file_extent_item *fi; | |
73 | struct btrfs_key key; | |
74 | u64 disk_byte; | |
75 | ||
76 | add_parent: | |
77 | ret = ulist_add(parents, eb->start, 0, GFP_NOFS); | |
78 | if (ret < 0) | |
79 | return ret; | |
80 | ||
81 | if (level != 0) | |
82 | return 0; | |
83 | ||
84 | /* | |
85 | * if the current leaf is full with EXTENT_DATA items, we must | |
86 | * check the next one if that holds a reference as well. | |
87 | * ref->count cannot be used to skip this check. | |
88 | * repeat this until we don't find any additional EXTENT_DATA items. | |
89 | */ | |
90 | while (1) { | |
91 | ret = btrfs_next_leaf(root, path); | |
92 | if (ret < 0) | |
93 | return ret; | |
94 | if (ret) | |
95 | return 0; | |
96 | ||
97 | eb = path->nodes[0]; | |
98 | for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) { | |
99 | btrfs_item_key_to_cpu(eb, &key, slot); | |
100 | if (key.objectid != wanted_objectid || | |
101 | key.type != BTRFS_EXTENT_DATA_KEY) | |
102 | return 0; | |
103 | fi = btrfs_item_ptr(eb, slot, | |
104 | struct btrfs_file_extent_item); | |
105 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
106 | if (disk_byte == wanted_disk_byte) | |
107 | goto add_parent; | |
108 | } | |
109 | } | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | /* | |
115 | * resolve an indirect backref in the form (root_id, key, level) | |
116 | * to a logical address | |
117 | */ | |
118 | static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, | |
119 | struct __prelim_ref *ref, | |
120 | struct ulist *parents) | |
121 | { | |
122 | struct btrfs_path *path; | |
123 | struct btrfs_root *root; | |
124 | struct btrfs_key root_key; | |
125 | struct btrfs_key key = {0}; | |
126 | struct extent_buffer *eb; | |
127 | int ret = 0; | |
128 | int root_level; | |
129 | int level = ref->level; | |
130 | ||
131 | path = btrfs_alloc_path(); | |
132 | if (!path) | |
133 | return -ENOMEM; | |
134 | ||
135 | root_key.objectid = ref->root_id; | |
136 | root_key.type = BTRFS_ROOT_ITEM_KEY; | |
137 | root_key.offset = (u64)-1; | |
138 | root = btrfs_read_fs_root_no_name(fs_info, &root_key); | |
139 | if (IS_ERR(root)) { | |
140 | ret = PTR_ERR(root); | |
141 | goto out; | |
142 | } | |
143 | ||
144 | rcu_read_lock(); | |
145 | root_level = btrfs_header_level(root->node); | |
146 | rcu_read_unlock(); | |
147 | ||
148 | if (root_level + 1 == level) | |
149 | goto out; | |
150 | ||
151 | path->lowest_level = level; | |
152 | ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0); | |
153 | pr_debug("search slot in root %llu (level %d, ref count %d) returned " | |
154 | "%d for key (%llu %u %llu)\n", | |
155 | (unsigned long long)ref->root_id, level, ref->count, ret, | |
156 | (unsigned long long)ref->key.objectid, ref->key.type, | |
157 | (unsigned long long)ref->key.offset); | |
158 | if (ret < 0) | |
159 | goto out; | |
160 | ||
161 | eb = path->nodes[level]; | |
162 | if (!eb) { | |
163 | WARN_ON(1); | |
164 | ret = 1; | |
165 | goto out; | |
166 | } | |
167 | ||
168 | if (level == 0) { | |
169 | if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) { | |
170 | ret = btrfs_next_leaf(root, path); | |
171 | if (ret) | |
172 | goto out; | |
173 | eb = path->nodes[0]; | |
174 | } | |
175 | ||
176 | btrfs_item_key_to_cpu(eb, &key, path->slots[0]); | |
177 | } | |
178 | ||
179 | /* the last two parameters will only be used for level == 0 */ | |
180 | ret = add_all_parents(root, path, parents, eb, level, key.objectid, | |
181 | ref->wanted_disk_byte); | |
182 | out: | |
183 | btrfs_free_path(path); | |
184 | return ret; | |
185 | } | |
186 | ||
187 | /* | |
188 | * resolve all indirect backrefs from the list | |
189 | */ | |
190 | static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, | |
191 | struct list_head *head) | |
192 | { | |
193 | int err; | |
194 | int ret = 0; | |
195 | struct __prelim_ref *ref; | |
196 | struct __prelim_ref *ref_safe; | |
197 | struct __prelim_ref *new_ref; | |
198 | struct ulist *parents; | |
199 | struct ulist_node *node; | |
200 | ||
201 | parents = ulist_alloc(GFP_NOFS); | |
202 | if (!parents) | |
203 | return -ENOMEM; | |
204 | ||
205 | /* | |
206 | * _safe allows us to insert directly after the current item without | |
207 | * iterating over the newly inserted items. | |
208 | * we're also allowed to re-assign ref during iteration. | |
209 | */ | |
210 | list_for_each_entry_safe(ref, ref_safe, head, list) { | |
211 | if (ref->parent) /* already direct */ | |
212 | continue; | |
213 | if (ref->count == 0) | |
214 | continue; | |
215 | err = __resolve_indirect_ref(fs_info, ref, parents); | |
216 | if (err) { | |
217 | if (ret == 0) | |
218 | ret = err; | |
219 | continue; | |
220 | } | |
221 | ||
222 | /* we put the first parent into the ref at hand */ | |
223 | node = ulist_next(parents, NULL); | |
224 | ref->parent = node ? node->val : 0; | |
225 | ||
226 | /* additional parents require new refs being added here */ | |
227 | while ((node = ulist_next(parents, node))) { | |
228 | new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); | |
229 | if (!new_ref) { | |
230 | ret = -ENOMEM; | |
231 | break; | |
232 | } | |
233 | memcpy(new_ref, ref, sizeof(*ref)); | |
234 | new_ref->parent = node->val; | |
235 | list_add(&new_ref->list, &ref->list); | |
236 | } | |
237 | ulist_reinit(parents); | |
238 | } | |
239 | ||
240 | ulist_free(parents); | |
241 | return ret; | |
242 | } | |
243 | ||
244 | /* | |
245 | * merge two lists of backrefs and adjust counts accordingly | |
246 | * | |
247 | * mode = 1: merge identical keys, if key is set | |
248 | * mode = 2: merge identical parents | |
249 | */ | |
250 | static int __merge_refs(struct list_head *head, int mode) | |
251 | { | |
252 | struct list_head *pos1; | |
253 | ||
254 | list_for_each(pos1, head) { | |
255 | struct list_head *n2; | |
256 | struct list_head *pos2; | |
257 | struct __prelim_ref *ref1; | |
258 | ||
259 | ref1 = list_entry(pos1, struct __prelim_ref, list); | |
260 | ||
261 | if (mode == 1 && ref1->key.type == 0) | |
262 | continue; | |
263 | for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; | |
264 | pos2 = n2, n2 = pos2->next) { | |
265 | struct __prelim_ref *ref2; | |
266 | ||
267 | ref2 = list_entry(pos2, struct __prelim_ref, list); | |
268 | ||
269 | if (mode == 1) { | |
270 | if (memcmp(&ref1->key, &ref2->key, | |
271 | sizeof(ref1->key)) || | |
272 | ref1->level != ref2->level || | |
273 | ref1->root_id != ref2->root_id) | |
274 | continue; | |
275 | ref1->count += ref2->count; | |
276 | } else { | |
277 | if (ref1->parent != ref2->parent) | |
278 | continue; | |
279 | ref1->count += ref2->count; | |
280 | } | |
281 | list_del(&ref2->list); | |
282 | kfree(ref2); | |
283 | } | |
284 | ||
285 | } | |
286 | return 0; | |
287 | } | |
288 | ||
289 | /* | |
290 | * add all currently queued delayed refs from this head whose seq nr is | |
291 | * smaller or equal that seq to the list | |
292 | */ | |
293 | static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, | |
294 | struct btrfs_key *info_key, | |
295 | struct list_head *prefs) | |
296 | { | |
297 | struct btrfs_delayed_extent_op *extent_op = head->extent_op; | |
298 | struct rb_node *n = &head->node.rb_node; | |
299 | int sgn; | |
b1375d64 | 300 | int ret = 0; |
8da6d581 JS |
301 | |
302 | if (extent_op && extent_op->update_key) | |
303 | btrfs_disk_key_to_cpu(info_key, &extent_op->key); | |
304 | ||
305 | while ((n = rb_prev(n))) { | |
306 | struct btrfs_delayed_ref_node *node; | |
307 | node = rb_entry(n, struct btrfs_delayed_ref_node, | |
308 | rb_node); | |
309 | if (node->bytenr != head->node.bytenr) | |
310 | break; | |
311 | WARN_ON(node->is_head); | |
312 | ||
313 | if (node->seq > seq) | |
314 | continue; | |
315 | ||
316 | switch (node->action) { | |
317 | case BTRFS_ADD_DELAYED_EXTENT: | |
318 | case BTRFS_UPDATE_DELAYED_HEAD: | |
319 | WARN_ON(1); | |
320 | continue; | |
321 | case BTRFS_ADD_DELAYED_REF: | |
322 | sgn = 1; | |
323 | break; | |
324 | case BTRFS_DROP_DELAYED_REF: | |
325 | sgn = -1; | |
326 | break; | |
327 | default: | |
328 | BUG_ON(1); | |
329 | } | |
330 | switch (node->type) { | |
331 | case BTRFS_TREE_BLOCK_REF_KEY: { | |
332 | struct btrfs_delayed_tree_ref *ref; | |
333 | ||
334 | ref = btrfs_delayed_node_to_tree_ref(node); | |
335 | ret = __add_prelim_ref(prefs, ref->root, info_key, | |
336 | ref->level + 1, 0, node->bytenr, | |
337 | node->ref_mod * sgn); | |
338 | break; | |
339 | } | |
340 | case BTRFS_SHARED_BLOCK_REF_KEY: { | |
341 | struct btrfs_delayed_tree_ref *ref; | |
342 | ||
343 | ref = btrfs_delayed_node_to_tree_ref(node); | |
344 | ret = __add_prelim_ref(prefs, ref->root, info_key, | |
345 | ref->level + 1, ref->parent, | |
346 | node->bytenr, | |
347 | node->ref_mod * sgn); | |
348 | break; | |
349 | } | |
350 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
351 | struct btrfs_delayed_data_ref *ref; | |
352 | struct btrfs_key key; | |
353 | ||
354 | ref = btrfs_delayed_node_to_data_ref(node); | |
355 | ||
356 | key.objectid = ref->objectid; | |
357 | key.type = BTRFS_EXTENT_DATA_KEY; | |
358 | key.offset = ref->offset; | |
359 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, | |
360 | node->bytenr, | |
361 | node->ref_mod * sgn); | |
362 | break; | |
363 | } | |
364 | case BTRFS_SHARED_DATA_REF_KEY: { | |
365 | struct btrfs_delayed_data_ref *ref; | |
366 | struct btrfs_key key; | |
367 | ||
368 | ref = btrfs_delayed_node_to_data_ref(node); | |
369 | ||
370 | key.objectid = ref->objectid; | |
371 | key.type = BTRFS_EXTENT_DATA_KEY; | |
372 | key.offset = ref->offset; | |
373 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, | |
374 | ref->parent, node->bytenr, | |
375 | node->ref_mod * sgn); | |
376 | break; | |
377 | } | |
378 | default: | |
379 | WARN_ON(1); | |
380 | } | |
381 | BUG_ON(ret); | |
382 | } | |
383 | ||
384 | return 0; | |
385 | } | |
386 | ||
387 | /* | |
388 | * add all inline backrefs for bytenr to the list | |
389 | */ | |
390 | static int __add_inline_refs(struct btrfs_fs_info *fs_info, | |
391 | struct btrfs_path *path, u64 bytenr, | |
392 | struct btrfs_key *info_key, int *info_level, | |
393 | struct list_head *prefs) | |
394 | { | |
b1375d64 | 395 | int ret = 0; |
8da6d581 JS |
396 | int slot; |
397 | struct extent_buffer *leaf; | |
398 | struct btrfs_key key; | |
399 | unsigned long ptr; | |
400 | unsigned long end; | |
401 | struct btrfs_extent_item *ei; | |
402 | u64 flags; | |
403 | u64 item_size; | |
404 | ||
405 | /* | |
406 | * enumerate all inline refs | |
407 | */ | |
408 | leaf = path->nodes[0]; | |
409 | slot = path->slots[0] - 1; | |
410 | ||
411 | item_size = btrfs_item_size_nr(leaf, slot); | |
412 | BUG_ON(item_size < sizeof(*ei)); | |
413 | ||
414 | ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); | |
415 | flags = btrfs_extent_flags(leaf, ei); | |
416 | ||
417 | ptr = (unsigned long)(ei + 1); | |
418 | end = (unsigned long)ei + item_size; | |
419 | ||
420 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
421 | struct btrfs_tree_block_info *info; | |
422 | struct btrfs_disk_key disk_key; | |
423 | ||
424 | info = (struct btrfs_tree_block_info *)ptr; | |
425 | *info_level = btrfs_tree_block_level(leaf, info); | |
426 | btrfs_tree_block_key(leaf, info, &disk_key); | |
427 | btrfs_disk_key_to_cpu(info_key, &disk_key); | |
428 | ptr += sizeof(struct btrfs_tree_block_info); | |
429 | BUG_ON(ptr > end); | |
430 | } else { | |
431 | BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); | |
432 | } | |
433 | ||
434 | while (ptr < end) { | |
435 | struct btrfs_extent_inline_ref *iref; | |
436 | u64 offset; | |
437 | int type; | |
438 | ||
439 | iref = (struct btrfs_extent_inline_ref *)ptr; | |
440 | type = btrfs_extent_inline_ref_type(leaf, iref); | |
441 | offset = btrfs_extent_inline_ref_offset(leaf, iref); | |
442 | ||
443 | switch (type) { | |
444 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
445 | ret = __add_prelim_ref(prefs, 0, info_key, | |
446 | *info_level + 1, offset, | |
447 | bytenr, 1); | |
448 | break; | |
449 | case BTRFS_SHARED_DATA_REF_KEY: { | |
450 | struct btrfs_shared_data_ref *sdref; | |
451 | int count; | |
452 | ||
453 | sdref = (struct btrfs_shared_data_ref *)(iref + 1); | |
454 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
455 | ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, | |
456 | bytenr, count); | |
457 | break; | |
458 | } | |
459 | case BTRFS_TREE_BLOCK_REF_KEY: | |
460 | ret = __add_prelim_ref(prefs, offset, info_key, | |
461 | *info_level + 1, 0, bytenr, 1); | |
462 | break; | |
463 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
464 | struct btrfs_extent_data_ref *dref; | |
465 | int count; | |
466 | u64 root; | |
467 | ||
468 | dref = (struct btrfs_extent_data_ref *)(&iref->offset); | |
469 | count = btrfs_extent_data_ref_count(leaf, dref); | |
470 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
471 | dref); | |
472 | key.type = BTRFS_EXTENT_DATA_KEY; | |
473 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
474 | root = btrfs_extent_data_ref_root(leaf, dref); | |
475 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr, | |
476 | count); | |
477 | break; | |
478 | } | |
479 | default: | |
480 | WARN_ON(1); | |
481 | } | |
482 | BUG_ON(ret); | |
483 | ptr += btrfs_extent_inline_ref_size(type); | |
484 | } | |
485 | ||
486 | return 0; | |
487 | } | |
488 | ||
489 | /* | |
490 | * add all non-inline backrefs for bytenr to the list | |
491 | */ | |
492 | static int __add_keyed_refs(struct btrfs_fs_info *fs_info, | |
493 | struct btrfs_path *path, u64 bytenr, | |
494 | struct btrfs_key *info_key, int info_level, | |
495 | struct list_head *prefs) | |
496 | { | |
497 | struct btrfs_root *extent_root = fs_info->extent_root; | |
498 | int ret; | |
499 | int slot; | |
500 | struct extent_buffer *leaf; | |
501 | struct btrfs_key key; | |
502 | ||
503 | while (1) { | |
504 | ret = btrfs_next_item(extent_root, path); | |
505 | if (ret < 0) | |
506 | break; | |
507 | if (ret) { | |
508 | ret = 0; | |
509 | break; | |
510 | } | |
511 | ||
512 | slot = path->slots[0]; | |
513 | leaf = path->nodes[0]; | |
514 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
515 | ||
516 | if (key.objectid != bytenr) | |
517 | break; | |
518 | if (key.type < BTRFS_TREE_BLOCK_REF_KEY) | |
519 | continue; | |
520 | if (key.type > BTRFS_SHARED_DATA_REF_KEY) | |
521 | break; | |
522 | ||
523 | switch (key.type) { | |
524 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
525 | ret = __add_prelim_ref(prefs, 0, info_key, | |
526 | info_level + 1, key.offset, | |
527 | bytenr, 1); | |
528 | break; | |
529 | case BTRFS_SHARED_DATA_REF_KEY: { | |
530 | struct btrfs_shared_data_ref *sdref; | |
531 | int count; | |
532 | ||
533 | sdref = btrfs_item_ptr(leaf, slot, | |
534 | struct btrfs_shared_data_ref); | |
535 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
536 | ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, | |
537 | bytenr, count); | |
538 | break; | |
539 | } | |
540 | case BTRFS_TREE_BLOCK_REF_KEY: | |
541 | ret = __add_prelim_ref(prefs, key.offset, info_key, | |
542 | info_level + 1, 0, bytenr, 1); | |
543 | break; | |
544 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
545 | struct btrfs_extent_data_ref *dref; | |
546 | int count; | |
547 | u64 root; | |
548 | ||
549 | dref = btrfs_item_ptr(leaf, slot, | |
550 | struct btrfs_extent_data_ref); | |
551 | count = btrfs_extent_data_ref_count(leaf, dref); | |
552 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
553 | dref); | |
554 | key.type = BTRFS_EXTENT_DATA_KEY; | |
555 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
556 | root = btrfs_extent_data_ref_root(leaf, dref); | |
557 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, | |
558 | bytenr, count); | |
559 | break; | |
560 | } | |
561 | default: | |
562 | WARN_ON(1); | |
563 | } | |
564 | BUG_ON(ret); | |
565 | } | |
566 | ||
567 | return ret; | |
568 | } | |
569 | ||
570 | /* | |
571 | * this adds all existing backrefs (inline backrefs, backrefs and delayed | |
572 | * refs) for the given bytenr to the refs list, merges duplicates and resolves | |
573 | * indirect refs to their parent bytenr. | |
574 | * When roots are found, they're added to the roots list | |
575 | * | |
576 | * FIXME some caching might speed things up | |
577 | */ | |
578 | static int find_parent_nodes(struct btrfs_trans_handle *trans, | |
579 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
580 | u64 seq, struct ulist *refs, struct ulist *roots) | |
581 | { | |
582 | struct btrfs_key key; | |
583 | struct btrfs_path *path; | |
584 | struct btrfs_key info_key = { 0 }; | |
585 | struct btrfs_delayed_ref_root *delayed_refs = NULL; | |
586 | struct btrfs_delayed_ref_head *head = NULL; | |
587 | int info_level = 0; | |
588 | int ret; | |
589 | struct list_head prefs_delayed; | |
590 | struct list_head prefs; | |
591 | struct __prelim_ref *ref; | |
592 | ||
593 | INIT_LIST_HEAD(&prefs); | |
594 | INIT_LIST_HEAD(&prefs_delayed); | |
595 | ||
596 | key.objectid = bytenr; | |
597 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
598 | key.offset = (u64)-1; | |
599 | ||
600 | path = btrfs_alloc_path(); | |
601 | if (!path) | |
602 | return -ENOMEM; | |
603 | ||
604 | /* | |
605 | * grab both a lock on the path and a lock on the delayed ref head. | |
606 | * We need both to get a consistent picture of how the refs look | |
607 | * at a specified point in time | |
608 | */ | |
609 | again: | |
610 | ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); | |
611 | if (ret < 0) | |
612 | goto out; | |
613 | BUG_ON(ret == 0); | |
614 | ||
615 | /* | |
616 | * look if there are updates for this ref queued and lock the head | |
617 | */ | |
618 | delayed_refs = &trans->transaction->delayed_refs; | |
619 | spin_lock(&delayed_refs->lock); | |
620 | head = btrfs_find_delayed_ref_head(trans, bytenr); | |
621 | if (head) { | |
622 | if (!mutex_trylock(&head->mutex)) { | |
623 | atomic_inc(&head->node.refs); | |
624 | spin_unlock(&delayed_refs->lock); | |
625 | ||
626 | btrfs_release_path(path); | |
627 | ||
628 | /* | |
629 | * Mutex was contended, block until it's | |
630 | * released and try again | |
631 | */ | |
632 | mutex_lock(&head->mutex); | |
633 | mutex_unlock(&head->mutex); | |
634 | btrfs_put_delayed_ref(&head->node); | |
635 | goto again; | |
636 | } | |
637 | ret = __add_delayed_refs(head, seq, &info_key, &prefs_delayed); | |
638 | if (ret) | |
639 | goto out; | |
640 | } | |
641 | spin_unlock(&delayed_refs->lock); | |
642 | ||
643 | if (path->slots[0]) { | |
644 | struct extent_buffer *leaf; | |
645 | int slot; | |
646 | ||
647 | leaf = path->nodes[0]; | |
648 | slot = path->slots[0] - 1; | |
649 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
650 | if (key.objectid == bytenr && | |
651 | key.type == BTRFS_EXTENT_ITEM_KEY) { | |
652 | ret = __add_inline_refs(fs_info, path, bytenr, | |
653 | &info_key, &info_level, &prefs); | |
654 | if (ret) | |
655 | goto out; | |
656 | ret = __add_keyed_refs(fs_info, path, bytenr, &info_key, | |
657 | info_level, &prefs); | |
658 | if (ret) | |
659 | goto out; | |
660 | } | |
661 | } | |
662 | btrfs_release_path(path); | |
663 | ||
664 | /* | |
665 | * when adding the delayed refs above, the info_key might not have | |
666 | * been known yet. Go over the list and replace the missing keys | |
667 | */ | |
668 | list_for_each_entry(ref, &prefs_delayed, list) { | |
669 | if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0) | |
670 | memcpy(&ref->key, &info_key, sizeof(ref->key)); | |
671 | } | |
672 | list_splice_init(&prefs_delayed, &prefs); | |
673 | ||
674 | ret = __merge_refs(&prefs, 1); | |
675 | if (ret) | |
676 | goto out; | |
677 | ||
678 | ret = __resolve_indirect_refs(fs_info, &prefs); | |
679 | if (ret) | |
680 | goto out; | |
681 | ||
682 | ret = __merge_refs(&prefs, 2); | |
683 | if (ret) | |
684 | goto out; | |
685 | ||
686 | while (!list_empty(&prefs)) { | |
687 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
688 | list_del(&ref->list); | |
689 | if (ref->count < 0) | |
690 | WARN_ON(1); | |
691 | if (ref->count && ref->root_id && ref->parent == 0) { | |
692 | /* no parent == root of tree */ | |
693 | ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); | |
694 | BUG_ON(ret < 0); | |
695 | } | |
696 | if (ref->count && ref->parent) { | |
697 | ret = ulist_add(refs, ref->parent, 0, GFP_NOFS); | |
698 | BUG_ON(ret < 0); | |
699 | } | |
700 | kfree(ref); | |
701 | } | |
702 | ||
703 | out: | |
704 | if (head) | |
705 | mutex_unlock(&head->mutex); | |
706 | btrfs_free_path(path); | |
707 | while (!list_empty(&prefs)) { | |
708 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
709 | list_del(&ref->list); | |
710 | kfree(ref); | |
711 | } | |
712 | while (!list_empty(&prefs_delayed)) { | |
713 | ref = list_first_entry(&prefs_delayed, struct __prelim_ref, | |
714 | list); | |
715 | list_del(&ref->list); | |
716 | kfree(ref); | |
717 | } | |
718 | ||
719 | return ret; | |
720 | } | |
721 | ||
722 | /* | |
723 | * Finds all leafs with a reference to the specified combination of bytenr and | |
724 | * offset. key_list_head will point to a list of corresponding keys (caller must | |
725 | * free each list element). The leafs will be stored in the leafs ulist, which | |
726 | * must be freed with ulist_free. | |
727 | * | |
728 | * returns 0 on success, <0 on error | |
729 | */ | |
730 | static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, | |
731 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
732 | u64 num_bytes, u64 seq, struct ulist **leafs) | |
733 | { | |
734 | struct ulist *tmp; | |
735 | int ret; | |
736 | ||
737 | tmp = ulist_alloc(GFP_NOFS); | |
738 | if (!tmp) | |
739 | return -ENOMEM; | |
740 | *leafs = ulist_alloc(GFP_NOFS); | |
741 | if (!*leafs) { | |
742 | ulist_free(tmp); | |
743 | return -ENOMEM; | |
744 | } | |
745 | ||
746 | ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp); | |
747 | ulist_free(tmp); | |
748 | ||
749 | if (ret < 0 && ret != -ENOENT) { | |
750 | ulist_free(*leafs); | |
751 | return ret; | |
752 | } | |
753 | ||
754 | return 0; | |
755 | } | |
756 | ||
757 | /* | |
758 | * walk all backrefs for a given extent to find all roots that reference this | |
759 | * extent. Walking a backref means finding all extents that reference this | |
760 | * extent and in turn walk the backrefs of those, too. Naturally this is a | |
761 | * recursive process, but here it is implemented in an iterative fashion: We | |
762 | * find all referencing extents for the extent in question and put them on a | |
763 | * list. In turn, we find all referencing extents for those, further appending | |
764 | * to the list. The way we iterate the list allows adding more elements after | |
765 | * the current while iterating. The process stops when we reach the end of the | |
766 | * list. Found roots are added to the roots list. | |
767 | * | |
768 | * returns 0 on success, < 0 on error. | |
769 | */ | |
770 | int btrfs_find_all_roots(struct btrfs_trans_handle *trans, | |
771 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
772 | u64 num_bytes, u64 seq, struct ulist **roots) | |
773 | { | |
774 | struct ulist *tmp; | |
775 | struct ulist_node *node = NULL; | |
776 | int ret; | |
777 | ||
778 | tmp = ulist_alloc(GFP_NOFS); | |
779 | if (!tmp) | |
780 | return -ENOMEM; | |
781 | *roots = ulist_alloc(GFP_NOFS); | |
782 | if (!*roots) { | |
783 | ulist_free(tmp); | |
784 | return -ENOMEM; | |
785 | } | |
786 | ||
787 | while (1) { | |
788 | ret = find_parent_nodes(trans, fs_info, bytenr, seq, | |
789 | tmp, *roots); | |
790 | if (ret < 0 && ret != -ENOENT) { | |
791 | ulist_free(tmp); | |
792 | ulist_free(*roots); | |
793 | return ret; | |
794 | } | |
795 | node = ulist_next(tmp, node); | |
796 | if (!node) | |
797 | break; | |
798 | bytenr = node->val; | |
799 | } | |
800 | ||
801 | ulist_free(tmp); | |
802 | return 0; | |
803 | } | |
804 | ||
805 | ||
a542ad1b JS |
806 | static int __inode_info(u64 inum, u64 ioff, u8 key_type, |
807 | struct btrfs_root *fs_root, struct btrfs_path *path, | |
808 | struct btrfs_key *found_key) | |
809 | { | |
810 | int ret; | |
811 | struct btrfs_key key; | |
812 | struct extent_buffer *eb; | |
813 | ||
814 | key.type = key_type; | |
815 | key.objectid = inum; | |
816 | key.offset = ioff; | |
817 | ||
818 | ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); | |
819 | if (ret < 0) | |
820 | return ret; | |
821 | ||
822 | eb = path->nodes[0]; | |
823 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { | |
824 | ret = btrfs_next_leaf(fs_root, path); | |
825 | if (ret) | |
826 | return ret; | |
827 | eb = path->nodes[0]; | |
828 | } | |
829 | ||
830 | btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); | |
831 | if (found_key->type != key.type || found_key->objectid != key.objectid) | |
832 | return 1; | |
833 | ||
834 | return 0; | |
835 | } | |
836 | ||
837 | /* | |
838 | * this makes the path point to (inum INODE_ITEM ioff) | |
839 | */ | |
840 | int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
841 | struct btrfs_path *path) | |
842 | { | |
843 | struct btrfs_key key; | |
844 | return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, | |
845 | &key); | |
846 | } | |
847 | ||
848 | static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
849 | struct btrfs_path *path, | |
850 | struct btrfs_key *found_key) | |
851 | { | |
852 | return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, | |
853 | found_key); | |
854 | } | |
855 | ||
856 | /* | |
857 | * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements | |
858 | * of the path are separated by '/' and the path is guaranteed to be | |
859 | * 0-terminated. the path is only given within the current file system. | |
860 | * Therefore, it never starts with a '/'. the caller is responsible to provide | |
861 | * "size" bytes in "dest". the dest buffer will be filled backwards. finally, | |
862 | * the start point of the resulting string is returned. this pointer is within | |
863 | * dest, normally. | |
864 | * in case the path buffer would overflow, the pointer is decremented further | |
865 | * as if output was written to the buffer, though no more output is actually | |
866 | * generated. that way, the caller can determine how much space would be | |
867 | * required for the path to fit into the buffer. in that case, the returned | |
868 | * value will be smaller than dest. callers must check this! | |
869 | */ | |
870 | static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, | |
871 | struct btrfs_inode_ref *iref, | |
872 | struct extent_buffer *eb_in, u64 parent, | |
873 | char *dest, u32 size) | |
874 | { | |
875 | u32 len; | |
876 | int slot; | |
877 | u64 next_inum; | |
878 | int ret; | |
879 | s64 bytes_left = size - 1; | |
880 | struct extent_buffer *eb = eb_in; | |
881 | struct btrfs_key found_key; | |
882 | ||
883 | if (bytes_left >= 0) | |
884 | dest[bytes_left] = '\0'; | |
885 | ||
886 | while (1) { | |
887 | len = btrfs_inode_ref_name_len(eb, iref); | |
888 | bytes_left -= len; | |
889 | if (bytes_left >= 0) | |
890 | read_extent_buffer(eb, dest + bytes_left, | |
891 | (unsigned long)(iref + 1), len); | |
892 | if (eb != eb_in) | |
893 | free_extent_buffer(eb); | |
894 | ret = inode_ref_info(parent, 0, fs_root, path, &found_key); | |
895 | if (ret) | |
896 | break; | |
897 | next_inum = found_key.offset; | |
898 | ||
899 | /* regular exit ahead */ | |
900 | if (parent == next_inum) | |
901 | break; | |
902 | ||
903 | slot = path->slots[0]; | |
904 | eb = path->nodes[0]; | |
905 | /* make sure we can use eb after releasing the path */ | |
906 | if (eb != eb_in) | |
907 | atomic_inc(&eb->refs); | |
908 | btrfs_release_path(path); | |
909 | ||
910 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
911 | parent = next_inum; | |
912 | --bytes_left; | |
913 | if (bytes_left >= 0) | |
914 | dest[bytes_left] = '/'; | |
915 | } | |
916 | ||
917 | btrfs_release_path(path); | |
918 | ||
919 | if (ret) | |
920 | return ERR_PTR(ret); | |
921 | ||
922 | return dest + bytes_left; | |
923 | } | |
924 | ||
925 | /* | |
926 | * this makes the path point to (logical EXTENT_ITEM *) | |
927 | * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for | |
928 | * tree blocks and <0 on error. | |
929 | */ | |
930 | int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, | |
931 | struct btrfs_path *path, struct btrfs_key *found_key) | |
932 | { | |
933 | int ret; | |
934 | u64 flags; | |
935 | u32 item_size; | |
936 | struct extent_buffer *eb; | |
937 | struct btrfs_extent_item *ei; | |
938 | struct btrfs_key key; | |
939 | ||
940 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
941 | key.objectid = logical; | |
942 | key.offset = (u64)-1; | |
943 | ||
944 | ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); | |
945 | if (ret < 0) | |
946 | return ret; | |
947 | ret = btrfs_previous_item(fs_info->extent_root, path, | |
948 | 0, BTRFS_EXTENT_ITEM_KEY); | |
949 | if (ret < 0) | |
950 | return ret; | |
951 | ||
952 | btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); | |
953 | if (found_key->type != BTRFS_EXTENT_ITEM_KEY || | |
954 | found_key->objectid > logical || | |
4692cf58 JS |
955 | found_key->objectid + found_key->offset <= logical) { |
956 | pr_debug("logical %llu is not within any extent\n", | |
957 | (unsigned long long)logical); | |
a542ad1b | 958 | return -ENOENT; |
4692cf58 | 959 | } |
a542ad1b JS |
960 | |
961 | eb = path->nodes[0]; | |
962 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
963 | BUG_ON(item_size < sizeof(*ei)); | |
964 | ||
965 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
966 | flags = btrfs_extent_flags(eb, ei); | |
967 | ||
4692cf58 JS |
968 | pr_debug("logical %llu is at position %llu within the extent (%llu " |
969 | "EXTENT_ITEM %llu) flags %#llx size %u\n", | |
970 | (unsigned long long)logical, | |
971 | (unsigned long long)(logical - found_key->objectid), | |
972 | (unsigned long long)found_key->objectid, | |
973 | (unsigned long long)found_key->offset, | |
974 | (unsigned long long)flags, item_size); | |
a542ad1b JS |
975 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
976 | return BTRFS_EXTENT_FLAG_TREE_BLOCK; | |
977 | if (flags & BTRFS_EXTENT_FLAG_DATA) | |
978 | return BTRFS_EXTENT_FLAG_DATA; | |
979 | ||
980 | return -EIO; | |
981 | } | |
982 | ||
983 | /* | |
984 | * helper function to iterate extent inline refs. ptr must point to a 0 value | |
985 | * for the first call and may be modified. it is used to track state. | |
986 | * if more refs exist, 0 is returned and the next call to | |
987 | * __get_extent_inline_ref must pass the modified ptr parameter to get the | |
988 | * next ref. after the last ref was processed, 1 is returned. | |
989 | * returns <0 on error | |
990 | */ | |
991 | static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, | |
992 | struct btrfs_extent_item *ei, u32 item_size, | |
993 | struct btrfs_extent_inline_ref **out_eiref, | |
994 | int *out_type) | |
995 | { | |
996 | unsigned long end; | |
997 | u64 flags; | |
998 | struct btrfs_tree_block_info *info; | |
999 | ||
1000 | if (!*ptr) { | |
1001 | /* first call */ | |
1002 | flags = btrfs_extent_flags(eb, ei); | |
1003 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
1004 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1005 | *out_eiref = | |
1006 | (struct btrfs_extent_inline_ref *)(info + 1); | |
1007 | } else { | |
1008 | *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); | |
1009 | } | |
1010 | *ptr = (unsigned long)*out_eiref; | |
1011 | if ((void *)*ptr >= (void *)ei + item_size) | |
1012 | return -ENOENT; | |
1013 | } | |
1014 | ||
1015 | end = (unsigned long)ei + item_size; | |
1016 | *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; | |
1017 | *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); | |
1018 | ||
1019 | *ptr += btrfs_extent_inline_ref_size(*out_type); | |
1020 | WARN_ON(*ptr > end); | |
1021 | if (*ptr == end) | |
1022 | return 1; /* last */ | |
1023 | ||
1024 | return 0; | |
1025 | } | |
1026 | ||
1027 | /* | |
1028 | * reads the tree block backref for an extent. tree level and root are returned | |
1029 | * through out_level and out_root. ptr must point to a 0 value for the first | |
1030 | * call and may be modified (see __get_extent_inline_ref comment). | |
1031 | * returns 0 if data was provided, 1 if there was no more data to provide or | |
1032 | * <0 on error. | |
1033 | */ | |
1034 | int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, | |
1035 | struct btrfs_extent_item *ei, u32 item_size, | |
1036 | u64 *out_root, u8 *out_level) | |
1037 | { | |
1038 | int ret; | |
1039 | int type; | |
1040 | struct btrfs_tree_block_info *info; | |
1041 | struct btrfs_extent_inline_ref *eiref; | |
1042 | ||
1043 | if (*ptr == (unsigned long)-1) | |
1044 | return 1; | |
1045 | ||
1046 | while (1) { | |
1047 | ret = __get_extent_inline_ref(ptr, eb, ei, item_size, | |
1048 | &eiref, &type); | |
1049 | if (ret < 0) | |
1050 | return ret; | |
1051 | ||
1052 | if (type == BTRFS_TREE_BLOCK_REF_KEY || | |
1053 | type == BTRFS_SHARED_BLOCK_REF_KEY) | |
1054 | break; | |
1055 | ||
1056 | if (ret == 1) | |
1057 | return 1; | |
1058 | } | |
1059 | ||
1060 | /* we can treat both ref types equally here */ | |
1061 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1062 | *out_root = btrfs_extent_inline_ref_offset(eb, eiref); | |
1063 | *out_level = btrfs_tree_block_level(eb, info); | |
1064 | ||
1065 | if (ret == 1) | |
1066 | *ptr = (unsigned long)-1; | |
1067 | ||
1068 | return 0; | |
1069 | } | |
1070 | ||
4692cf58 JS |
1071 | static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, |
1072 | struct btrfs_path *path, u64 logical, | |
1073 | u64 orig_extent_item_objectid, | |
1074 | u64 extent_item_pos, u64 root, | |
1075 | iterate_extent_inodes_t *iterate, void *ctx) | |
a542ad1b JS |
1076 | { |
1077 | u64 disk_byte; | |
1078 | struct btrfs_key key; | |
1079 | struct btrfs_file_extent_item *fi; | |
1080 | struct extent_buffer *eb; | |
1081 | int slot; | |
1082 | int nritems; | |
4692cf58 JS |
1083 | int ret = 0; |
1084 | int extent_type; | |
1085 | u64 data_offset; | |
1086 | u64 data_len; | |
a542ad1b JS |
1087 | |
1088 | eb = read_tree_block(fs_info->tree_root, logical, | |
1089 | fs_info->tree_root->leafsize, 0); | |
1090 | if (!eb) | |
1091 | return -EIO; | |
1092 | ||
1093 | /* | |
1094 | * from the shared data ref, we only have the leaf but we need | |
1095 | * the key. thus, we must look into all items and see that we | |
1096 | * find one (some) with a reference to our extent item. | |
1097 | */ | |
1098 | nritems = btrfs_header_nritems(eb); | |
1099 | for (slot = 0; slot < nritems; ++slot) { | |
1100 | btrfs_item_key_to_cpu(eb, &key, slot); | |
1101 | if (key.type != BTRFS_EXTENT_DATA_KEY) | |
1102 | continue; | |
1103 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
4692cf58 JS |
1104 | extent_type = btrfs_file_extent_type(eb, fi); |
1105 | if (extent_type == BTRFS_FILE_EXTENT_INLINE) | |
1106 | continue; | |
1107 | /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ | |
a542ad1b | 1108 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
4692cf58 JS |
1109 | if (disk_byte != orig_extent_item_objectid) |
1110 | continue; | |
a542ad1b | 1111 | |
4692cf58 JS |
1112 | data_offset = btrfs_file_extent_offset(eb, fi); |
1113 | data_len = btrfs_file_extent_num_bytes(eb, fi); | |
1114 | ||
1115 | if (extent_item_pos < data_offset || | |
1116 | extent_item_pos >= data_offset + data_len) | |
1117 | continue; | |
1118 | ||
1119 | pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " | |
1120 | "root %llu\n", orig_extent_item_objectid, | |
1121 | key.objectid, key.offset, root); | |
1122 | ret = iterate(key.objectid, | |
1123 | key.offset + (extent_item_pos - data_offset), | |
1124 | root, ctx); | |
1125 | if (ret) { | |
1126 | pr_debug("stopping iteration because ret=%d\n", ret); | |
1127 | break; | |
1128 | } | |
a542ad1b JS |
1129 | } |
1130 | ||
1131 | free_extent_buffer(eb); | |
4692cf58 | 1132 | |
a542ad1b JS |
1133 | return ret; |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * calls iterate() for every inode that references the extent identified by | |
4692cf58 | 1138 | * the given parameters. |
a542ad1b | 1139 | * when the iterator function returns a non-zero value, iteration stops. |
4692cf58 | 1140 | * path is guaranteed to be in released state when iterate() is called. |
a542ad1b JS |
1141 | */ |
1142 | int iterate_extent_inodes(struct btrfs_fs_info *fs_info, | |
1143 | struct btrfs_path *path, | |
4692cf58 | 1144 | u64 extent_item_objectid, u64 extent_item_pos, |
a542ad1b JS |
1145 | iterate_extent_inodes_t *iterate, void *ctx) |
1146 | { | |
a542ad1b | 1147 | int ret; |
a542ad1b JS |
1148 | struct list_head data_refs = LIST_HEAD_INIT(data_refs); |
1149 | struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); | |
4692cf58 JS |
1150 | struct btrfs_trans_handle *trans; |
1151 | struct ulist *refs; | |
1152 | struct ulist *roots; | |
1153 | struct ulist_node *ref_node = NULL; | |
1154 | struct ulist_node *root_node = NULL; | |
1155 | struct seq_list seq_elem; | |
1156 | struct btrfs_delayed_ref_root *delayed_refs; | |
a542ad1b | 1157 | |
4692cf58 JS |
1158 | trans = btrfs_join_transaction(fs_info->extent_root); |
1159 | if (IS_ERR(trans)) | |
1160 | return PTR_ERR(trans); | |
a542ad1b | 1161 | |
4692cf58 JS |
1162 | pr_debug("resolving all inodes for extent %llu\n", |
1163 | extent_item_objectid); | |
a542ad1b | 1164 | |
4692cf58 JS |
1165 | delayed_refs = &trans->transaction->delayed_refs; |
1166 | spin_lock(&delayed_refs->lock); | |
1167 | btrfs_get_delayed_seq(delayed_refs, &seq_elem); | |
1168 | spin_unlock(&delayed_refs->lock); | |
a542ad1b | 1169 | |
4692cf58 JS |
1170 | ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
1171 | extent_item_pos, seq_elem.seq, | |
1172 | &refs); | |
a542ad1b | 1173 | |
4692cf58 JS |
1174 | if (ret) |
1175 | goto out; | |
a542ad1b | 1176 | |
4692cf58 JS |
1177 | while (!ret && (ref_node = ulist_next(refs, ref_node))) { |
1178 | ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1, | |
1179 | seq_elem.seq, &roots); | |
1180 | if (ret) | |
1181 | break; | |
1182 | while (!ret && (root_node = ulist_next(roots, root_node))) { | |
1183 | pr_debug("root %llu references leaf %llu\n", | |
1184 | root_node->val, ref_node->val); | |
1185 | ret = iterate_leaf_refs(fs_info, path, ref_node->val, | |
1186 | extent_item_objectid, | |
1187 | extent_item_pos, root_node->val, | |
1188 | iterate, ctx); | |
1189 | } | |
a542ad1b JS |
1190 | } |
1191 | ||
4692cf58 JS |
1192 | ulist_free(refs); |
1193 | ulist_free(roots); | |
1194 | out: | |
1195 | btrfs_put_delayed_seq(delayed_refs, &seq_elem); | |
1196 | btrfs_end_transaction(trans, fs_info->extent_root); | |
a542ad1b JS |
1197 | return ret; |
1198 | } | |
1199 | ||
1200 | int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, | |
1201 | struct btrfs_path *path, | |
1202 | iterate_extent_inodes_t *iterate, void *ctx) | |
1203 | { | |
1204 | int ret; | |
4692cf58 | 1205 | u64 extent_item_pos; |
a542ad1b JS |
1206 | struct btrfs_key found_key; |
1207 | ||
1208 | ret = extent_from_logical(fs_info, logical, path, | |
1209 | &found_key); | |
4692cf58 | 1210 | btrfs_release_path(path); |
a542ad1b JS |
1211 | if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
1212 | ret = -EINVAL; | |
1213 | if (ret < 0) | |
1214 | return ret; | |
1215 | ||
4692cf58 | 1216 | extent_item_pos = logical - found_key.objectid; |
a542ad1b | 1217 | ret = iterate_extent_inodes(fs_info, path, found_key.objectid, |
4692cf58 | 1218 | extent_item_pos, iterate, ctx); |
a542ad1b JS |
1219 | |
1220 | return ret; | |
1221 | } | |
1222 | ||
1223 | static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, | |
1224 | struct btrfs_path *path, | |
1225 | iterate_irefs_t *iterate, void *ctx) | |
1226 | { | |
1227 | int ret; | |
1228 | int slot; | |
1229 | u32 cur; | |
1230 | u32 len; | |
1231 | u32 name_len; | |
1232 | u64 parent = 0; | |
1233 | int found = 0; | |
1234 | struct extent_buffer *eb; | |
1235 | struct btrfs_item *item; | |
1236 | struct btrfs_inode_ref *iref; | |
1237 | struct btrfs_key found_key; | |
1238 | ||
1239 | while (1) { | |
1240 | ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, | |
1241 | &found_key); | |
1242 | if (ret < 0) | |
1243 | break; | |
1244 | if (ret) { | |
1245 | ret = found ? 0 : -ENOENT; | |
1246 | break; | |
1247 | } | |
1248 | ++found; | |
1249 | ||
1250 | parent = found_key.offset; | |
1251 | slot = path->slots[0]; | |
1252 | eb = path->nodes[0]; | |
1253 | /* make sure we can use eb after releasing the path */ | |
1254 | atomic_inc(&eb->refs); | |
1255 | btrfs_release_path(path); | |
1256 | ||
1257 | item = btrfs_item_nr(eb, slot); | |
1258 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
1259 | ||
1260 | for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { | |
1261 | name_len = btrfs_inode_ref_name_len(eb, iref); | |
1262 | /* path must be released before calling iterate()! */ | |
4692cf58 JS |
1263 | pr_debug("following ref at offset %u for inode %llu in " |
1264 | "tree %llu\n", cur, | |
1265 | (unsigned long long)found_key.objectid, | |
1266 | (unsigned long long)fs_root->objectid); | |
a542ad1b JS |
1267 | ret = iterate(parent, iref, eb, ctx); |
1268 | if (ret) { | |
1269 | free_extent_buffer(eb); | |
1270 | break; | |
1271 | } | |
1272 | len = sizeof(*iref) + name_len; | |
1273 | iref = (struct btrfs_inode_ref *)((char *)iref + len); | |
1274 | } | |
1275 | free_extent_buffer(eb); | |
1276 | } | |
1277 | ||
1278 | btrfs_release_path(path); | |
1279 | ||
1280 | return ret; | |
1281 | } | |
1282 | ||
1283 | /* | |
1284 | * returns 0 if the path could be dumped (probably truncated) | |
1285 | * returns <0 in case of an error | |
1286 | */ | |
1287 | static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref, | |
1288 | struct extent_buffer *eb, void *ctx) | |
1289 | { | |
1290 | struct inode_fs_paths *ipath = ctx; | |
1291 | char *fspath; | |
1292 | char *fspath_min; | |
1293 | int i = ipath->fspath->elem_cnt; | |
1294 | const int s_ptr = sizeof(char *); | |
1295 | u32 bytes_left; | |
1296 | ||
1297 | bytes_left = ipath->fspath->bytes_left > s_ptr ? | |
1298 | ipath->fspath->bytes_left - s_ptr : 0; | |
1299 | ||
740c3d22 | 1300 | fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
a542ad1b JS |
1301 | fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb, |
1302 | inum, fspath_min, bytes_left); | |
1303 | if (IS_ERR(fspath)) | |
1304 | return PTR_ERR(fspath); | |
1305 | ||
1306 | if (fspath > fspath_min) { | |
4692cf58 | 1307 | pr_debug("path resolved: %s\n", fspath); |
745c4d8e | 1308 | ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
a542ad1b JS |
1309 | ++ipath->fspath->elem_cnt; |
1310 | ipath->fspath->bytes_left = fspath - fspath_min; | |
1311 | } else { | |
4692cf58 JS |
1312 | pr_debug("missed path, not enough space. missing bytes: %lu, " |
1313 | "constructed so far: %s\n", | |
1314 | (unsigned long)(fspath_min - fspath), fspath_min); | |
a542ad1b JS |
1315 | ++ipath->fspath->elem_missed; |
1316 | ipath->fspath->bytes_missing += fspath_min - fspath; | |
1317 | ipath->fspath->bytes_left = 0; | |
1318 | } | |
1319 | ||
1320 | return 0; | |
1321 | } | |
1322 | ||
1323 | /* | |
1324 | * this dumps all file system paths to the inode into the ipath struct, provided | |
1325 | * is has been created large enough. each path is zero-terminated and accessed | |
740c3d22 | 1326 | * from ipath->fspath->val[i]. |
a542ad1b | 1327 | * when it returns, there are ipath->fspath->elem_cnt number of paths available |
740c3d22 | 1328 | * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
a542ad1b JS |
1329 | * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, |
1330 | * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would | |
1331 | * have been needed to return all paths. | |
1332 | */ | |
1333 | int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) | |
1334 | { | |
1335 | return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, | |
1336 | inode_to_path, ipath); | |
1337 | } | |
1338 | ||
1339 | /* | |
1340 | * allocates space to return multiple file system paths for an inode. | |
1341 | * total_bytes to allocate are passed, note that space usable for actual path | |
1342 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1343 | * the returned pointer must be freed with free_ipath() in the end. | |
1344 | */ | |
1345 | struct btrfs_data_container *init_data_container(u32 total_bytes) | |
1346 | { | |
1347 | struct btrfs_data_container *data; | |
1348 | size_t alloc_bytes; | |
1349 | ||
1350 | alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); | |
1351 | data = kmalloc(alloc_bytes, GFP_NOFS); | |
1352 | if (!data) | |
1353 | return ERR_PTR(-ENOMEM); | |
1354 | ||
1355 | if (total_bytes >= sizeof(*data)) { | |
1356 | data->bytes_left = total_bytes - sizeof(*data); | |
1357 | data->bytes_missing = 0; | |
1358 | } else { | |
1359 | data->bytes_missing = sizeof(*data) - total_bytes; | |
1360 | data->bytes_left = 0; | |
1361 | } | |
1362 | ||
1363 | data->elem_cnt = 0; | |
1364 | data->elem_missed = 0; | |
1365 | ||
1366 | return data; | |
1367 | } | |
1368 | ||
1369 | /* | |
1370 | * allocates space to return multiple file system paths for an inode. | |
1371 | * total_bytes to allocate are passed, note that space usable for actual path | |
1372 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1373 | * the returned pointer must be freed with free_ipath() in the end. | |
1374 | */ | |
1375 | struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, | |
1376 | struct btrfs_path *path) | |
1377 | { | |
1378 | struct inode_fs_paths *ifp; | |
1379 | struct btrfs_data_container *fspath; | |
1380 | ||
1381 | fspath = init_data_container(total_bytes); | |
1382 | if (IS_ERR(fspath)) | |
1383 | return (void *)fspath; | |
1384 | ||
1385 | ifp = kmalloc(sizeof(*ifp), GFP_NOFS); | |
1386 | if (!ifp) { | |
1387 | kfree(fspath); | |
1388 | return ERR_PTR(-ENOMEM); | |
1389 | } | |
1390 | ||
1391 | ifp->btrfs_path = path; | |
1392 | ifp->fspath = fspath; | |
1393 | ifp->fs_root = fs_root; | |
1394 | ||
1395 | return ifp; | |
1396 | } | |
1397 | ||
1398 | void free_ipath(struct inode_fs_paths *ipath) | |
1399 | { | |
1400 | kfree(ipath); | |
1401 | } |