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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 JS |
25 | |
26 | struct __data_ref { | |
27 | struct list_head list; | |
28 | u64 inum; | |
29 | u64 root; | |
30 | u64 extent_data_item_offset; | |
31 | }; | |
32 | ||
33 | struct __shared_ref { | |
34 | struct list_head list; | |
35 | u64 disk_byte; | |
36 | }; | |
37 | ||
8da6d581 JS |
38 | /* |
39 | * this structure records all encountered refs on the way up to the root | |
40 | */ | |
41 | struct __prelim_ref { | |
42 | struct list_head list; | |
43 | u64 root_id; | |
44 | struct btrfs_key key; | |
45 | int level; | |
46 | int count; | |
47 | u64 parent; | |
48 | u64 wanted_disk_byte; | |
49 | }; | |
50 | ||
51 | static int __add_prelim_ref(struct list_head *head, u64 root_id, | |
52 | struct btrfs_key *key, int level, u64 parent, | |
53 | u64 wanted_disk_byte, int count) | |
54 | { | |
55 | struct __prelim_ref *ref; | |
56 | ||
57 | /* in case we're adding delayed refs, we're holding the refs spinlock */ | |
58 | ref = kmalloc(sizeof(*ref), GFP_ATOMIC); | |
59 | if (!ref) | |
60 | return -ENOMEM; | |
61 | ||
62 | ref->root_id = root_id; | |
63 | if (key) | |
64 | ref->key = *key; | |
65 | else | |
66 | memset(&ref->key, 0, sizeof(ref->key)); | |
67 | ||
68 | ref->level = level; | |
69 | ref->count = count; | |
70 | ref->parent = parent; | |
71 | ref->wanted_disk_byte = wanted_disk_byte; | |
72 | list_add_tail(&ref->list, head); | |
73 | ||
74 | return 0; | |
75 | } | |
76 | ||
77 | static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, | |
78 | struct ulist *parents, | |
79 | struct extent_buffer *eb, int level, | |
80 | u64 wanted_objectid, u64 wanted_disk_byte) | |
81 | { | |
82 | int ret; | |
83 | int slot; | |
84 | struct btrfs_file_extent_item *fi; | |
85 | struct btrfs_key key; | |
86 | u64 disk_byte; | |
87 | ||
88 | add_parent: | |
89 | ret = ulist_add(parents, eb->start, 0, GFP_NOFS); | |
90 | if (ret < 0) | |
91 | return ret; | |
92 | ||
93 | if (level != 0) | |
94 | return 0; | |
95 | ||
96 | /* | |
97 | * if the current leaf is full with EXTENT_DATA items, we must | |
98 | * check the next one if that holds a reference as well. | |
99 | * ref->count cannot be used to skip this check. | |
100 | * repeat this until we don't find any additional EXTENT_DATA items. | |
101 | */ | |
102 | while (1) { | |
103 | ret = btrfs_next_leaf(root, path); | |
104 | if (ret < 0) | |
105 | return ret; | |
106 | if (ret) | |
107 | return 0; | |
108 | ||
109 | eb = path->nodes[0]; | |
110 | for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) { | |
111 | btrfs_item_key_to_cpu(eb, &key, slot); | |
112 | if (key.objectid != wanted_objectid || | |
113 | key.type != BTRFS_EXTENT_DATA_KEY) | |
114 | return 0; | |
115 | fi = btrfs_item_ptr(eb, slot, | |
116 | struct btrfs_file_extent_item); | |
117 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
118 | if (disk_byte == wanted_disk_byte) | |
119 | goto add_parent; | |
120 | } | |
121 | } | |
122 | ||
123 | return 0; | |
124 | } | |
125 | ||
126 | /* | |
127 | * resolve an indirect backref in the form (root_id, key, level) | |
128 | * to a logical address | |
129 | */ | |
130 | static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, | |
131 | struct __prelim_ref *ref, | |
132 | struct ulist *parents) | |
133 | { | |
134 | struct btrfs_path *path; | |
135 | struct btrfs_root *root; | |
136 | struct btrfs_key root_key; | |
137 | struct btrfs_key key = {0}; | |
138 | struct extent_buffer *eb; | |
139 | int ret = 0; | |
140 | int root_level; | |
141 | int level = ref->level; | |
142 | ||
143 | path = btrfs_alloc_path(); | |
144 | if (!path) | |
145 | return -ENOMEM; | |
146 | ||
147 | root_key.objectid = ref->root_id; | |
148 | root_key.type = BTRFS_ROOT_ITEM_KEY; | |
149 | root_key.offset = (u64)-1; | |
150 | root = btrfs_read_fs_root_no_name(fs_info, &root_key); | |
151 | if (IS_ERR(root)) { | |
152 | ret = PTR_ERR(root); | |
153 | goto out; | |
154 | } | |
155 | ||
156 | rcu_read_lock(); | |
157 | root_level = btrfs_header_level(root->node); | |
158 | rcu_read_unlock(); | |
159 | ||
160 | if (root_level + 1 == level) | |
161 | goto out; | |
162 | ||
163 | path->lowest_level = level; | |
164 | ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0); | |
165 | pr_debug("search slot in root %llu (level %d, ref count %d) returned " | |
166 | "%d for key (%llu %u %llu)\n", | |
167 | (unsigned long long)ref->root_id, level, ref->count, ret, | |
168 | (unsigned long long)ref->key.objectid, ref->key.type, | |
169 | (unsigned long long)ref->key.offset); | |
170 | if (ret < 0) | |
171 | goto out; | |
172 | ||
173 | eb = path->nodes[level]; | |
174 | if (!eb) { | |
175 | WARN_ON(1); | |
176 | ret = 1; | |
177 | goto out; | |
178 | } | |
179 | ||
180 | if (level == 0) { | |
181 | if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) { | |
182 | ret = btrfs_next_leaf(root, path); | |
183 | if (ret) | |
184 | goto out; | |
185 | eb = path->nodes[0]; | |
186 | } | |
187 | ||
188 | btrfs_item_key_to_cpu(eb, &key, path->slots[0]); | |
189 | } | |
190 | ||
191 | /* the last two parameters will only be used for level == 0 */ | |
192 | ret = add_all_parents(root, path, parents, eb, level, key.objectid, | |
193 | ref->wanted_disk_byte); | |
194 | out: | |
195 | btrfs_free_path(path); | |
196 | return ret; | |
197 | } | |
198 | ||
199 | /* | |
200 | * resolve all indirect backrefs from the list | |
201 | */ | |
202 | static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, | |
203 | struct list_head *head) | |
204 | { | |
205 | int err; | |
206 | int ret = 0; | |
207 | struct __prelim_ref *ref; | |
208 | struct __prelim_ref *ref_safe; | |
209 | struct __prelim_ref *new_ref; | |
210 | struct ulist *parents; | |
211 | struct ulist_node *node; | |
212 | ||
213 | parents = ulist_alloc(GFP_NOFS); | |
214 | if (!parents) | |
215 | return -ENOMEM; | |
216 | ||
217 | /* | |
218 | * _safe allows us to insert directly after the current item without | |
219 | * iterating over the newly inserted items. | |
220 | * we're also allowed to re-assign ref during iteration. | |
221 | */ | |
222 | list_for_each_entry_safe(ref, ref_safe, head, list) { | |
223 | if (ref->parent) /* already direct */ | |
224 | continue; | |
225 | if (ref->count == 0) | |
226 | continue; | |
227 | err = __resolve_indirect_ref(fs_info, ref, parents); | |
228 | if (err) { | |
229 | if (ret == 0) | |
230 | ret = err; | |
231 | continue; | |
232 | } | |
233 | ||
234 | /* we put the first parent into the ref at hand */ | |
235 | node = ulist_next(parents, NULL); | |
236 | ref->parent = node ? node->val : 0; | |
237 | ||
238 | /* additional parents require new refs being added here */ | |
239 | while ((node = ulist_next(parents, node))) { | |
240 | new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); | |
241 | if (!new_ref) { | |
242 | ret = -ENOMEM; | |
243 | break; | |
244 | } | |
245 | memcpy(new_ref, ref, sizeof(*ref)); | |
246 | new_ref->parent = node->val; | |
247 | list_add(&new_ref->list, &ref->list); | |
248 | } | |
249 | ulist_reinit(parents); | |
250 | } | |
251 | ||
252 | ulist_free(parents); | |
253 | return ret; | |
254 | } | |
255 | ||
256 | /* | |
257 | * merge two lists of backrefs and adjust counts accordingly | |
258 | * | |
259 | * mode = 1: merge identical keys, if key is set | |
260 | * mode = 2: merge identical parents | |
261 | */ | |
262 | static int __merge_refs(struct list_head *head, int mode) | |
263 | { | |
264 | struct list_head *pos1; | |
265 | ||
266 | list_for_each(pos1, head) { | |
267 | struct list_head *n2; | |
268 | struct list_head *pos2; | |
269 | struct __prelim_ref *ref1; | |
270 | ||
271 | ref1 = list_entry(pos1, struct __prelim_ref, list); | |
272 | ||
273 | if (mode == 1 && ref1->key.type == 0) | |
274 | continue; | |
275 | for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; | |
276 | pos2 = n2, n2 = pos2->next) { | |
277 | struct __prelim_ref *ref2; | |
278 | ||
279 | ref2 = list_entry(pos2, struct __prelim_ref, list); | |
280 | ||
281 | if (mode == 1) { | |
282 | if (memcmp(&ref1->key, &ref2->key, | |
283 | sizeof(ref1->key)) || | |
284 | ref1->level != ref2->level || | |
285 | ref1->root_id != ref2->root_id) | |
286 | continue; | |
287 | ref1->count += ref2->count; | |
288 | } else { | |
289 | if (ref1->parent != ref2->parent) | |
290 | continue; | |
291 | ref1->count += ref2->count; | |
292 | } | |
293 | list_del(&ref2->list); | |
294 | kfree(ref2); | |
295 | } | |
296 | ||
297 | } | |
298 | return 0; | |
299 | } | |
300 | ||
301 | /* | |
302 | * add all currently queued delayed refs from this head whose seq nr is | |
303 | * smaller or equal that seq to the list | |
304 | */ | |
305 | static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, | |
306 | struct btrfs_key *info_key, | |
307 | struct list_head *prefs) | |
308 | { | |
309 | struct btrfs_delayed_extent_op *extent_op = head->extent_op; | |
310 | struct rb_node *n = &head->node.rb_node; | |
311 | int sgn; | |
312 | int ret; | |
313 | ||
314 | if (extent_op && extent_op->update_key) | |
315 | btrfs_disk_key_to_cpu(info_key, &extent_op->key); | |
316 | ||
317 | while ((n = rb_prev(n))) { | |
318 | struct btrfs_delayed_ref_node *node; | |
319 | node = rb_entry(n, struct btrfs_delayed_ref_node, | |
320 | rb_node); | |
321 | if (node->bytenr != head->node.bytenr) | |
322 | break; | |
323 | WARN_ON(node->is_head); | |
324 | ||
325 | if (node->seq > seq) | |
326 | continue; | |
327 | ||
328 | switch (node->action) { | |
329 | case BTRFS_ADD_DELAYED_EXTENT: | |
330 | case BTRFS_UPDATE_DELAYED_HEAD: | |
331 | WARN_ON(1); | |
332 | continue; | |
333 | case BTRFS_ADD_DELAYED_REF: | |
334 | sgn = 1; | |
335 | break; | |
336 | case BTRFS_DROP_DELAYED_REF: | |
337 | sgn = -1; | |
338 | break; | |
339 | default: | |
340 | BUG_ON(1); | |
341 | } | |
342 | switch (node->type) { | |
343 | case BTRFS_TREE_BLOCK_REF_KEY: { | |
344 | struct btrfs_delayed_tree_ref *ref; | |
345 | ||
346 | ref = btrfs_delayed_node_to_tree_ref(node); | |
347 | ret = __add_prelim_ref(prefs, ref->root, info_key, | |
348 | ref->level + 1, 0, node->bytenr, | |
349 | node->ref_mod * sgn); | |
350 | break; | |
351 | } | |
352 | case BTRFS_SHARED_BLOCK_REF_KEY: { | |
353 | struct btrfs_delayed_tree_ref *ref; | |
354 | ||
355 | ref = btrfs_delayed_node_to_tree_ref(node); | |
356 | ret = __add_prelim_ref(prefs, ref->root, info_key, | |
357 | ref->level + 1, ref->parent, | |
358 | node->bytenr, | |
359 | node->ref_mod * sgn); | |
360 | break; | |
361 | } | |
362 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
363 | struct btrfs_delayed_data_ref *ref; | |
364 | struct btrfs_key key; | |
365 | ||
366 | ref = btrfs_delayed_node_to_data_ref(node); | |
367 | ||
368 | key.objectid = ref->objectid; | |
369 | key.type = BTRFS_EXTENT_DATA_KEY; | |
370 | key.offset = ref->offset; | |
371 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, | |
372 | node->bytenr, | |
373 | node->ref_mod * sgn); | |
374 | break; | |
375 | } | |
376 | case BTRFS_SHARED_DATA_REF_KEY: { | |
377 | struct btrfs_delayed_data_ref *ref; | |
378 | struct btrfs_key key; | |
379 | ||
380 | ref = btrfs_delayed_node_to_data_ref(node); | |
381 | ||
382 | key.objectid = ref->objectid; | |
383 | key.type = BTRFS_EXTENT_DATA_KEY; | |
384 | key.offset = ref->offset; | |
385 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, | |
386 | ref->parent, node->bytenr, | |
387 | node->ref_mod * sgn); | |
388 | break; | |
389 | } | |
390 | default: | |
391 | WARN_ON(1); | |
392 | } | |
393 | BUG_ON(ret); | |
394 | } | |
395 | ||
396 | return 0; | |
397 | } | |
398 | ||
399 | /* | |
400 | * add all inline backrefs for bytenr to the list | |
401 | */ | |
402 | static int __add_inline_refs(struct btrfs_fs_info *fs_info, | |
403 | struct btrfs_path *path, u64 bytenr, | |
404 | struct btrfs_key *info_key, int *info_level, | |
405 | struct list_head *prefs) | |
406 | { | |
407 | int ret; | |
408 | int slot; | |
409 | struct extent_buffer *leaf; | |
410 | struct btrfs_key key; | |
411 | unsigned long ptr; | |
412 | unsigned long end; | |
413 | struct btrfs_extent_item *ei; | |
414 | u64 flags; | |
415 | u64 item_size; | |
416 | ||
417 | /* | |
418 | * enumerate all inline refs | |
419 | */ | |
420 | leaf = path->nodes[0]; | |
421 | slot = path->slots[0] - 1; | |
422 | ||
423 | item_size = btrfs_item_size_nr(leaf, slot); | |
424 | BUG_ON(item_size < sizeof(*ei)); | |
425 | ||
426 | ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); | |
427 | flags = btrfs_extent_flags(leaf, ei); | |
428 | ||
429 | ptr = (unsigned long)(ei + 1); | |
430 | end = (unsigned long)ei + item_size; | |
431 | ||
432 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
433 | struct btrfs_tree_block_info *info; | |
434 | struct btrfs_disk_key disk_key; | |
435 | ||
436 | info = (struct btrfs_tree_block_info *)ptr; | |
437 | *info_level = btrfs_tree_block_level(leaf, info); | |
438 | btrfs_tree_block_key(leaf, info, &disk_key); | |
439 | btrfs_disk_key_to_cpu(info_key, &disk_key); | |
440 | ptr += sizeof(struct btrfs_tree_block_info); | |
441 | BUG_ON(ptr > end); | |
442 | } else { | |
443 | BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); | |
444 | } | |
445 | ||
446 | while (ptr < end) { | |
447 | struct btrfs_extent_inline_ref *iref; | |
448 | u64 offset; | |
449 | int type; | |
450 | ||
451 | iref = (struct btrfs_extent_inline_ref *)ptr; | |
452 | type = btrfs_extent_inline_ref_type(leaf, iref); | |
453 | offset = btrfs_extent_inline_ref_offset(leaf, iref); | |
454 | ||
455 | switch (type) { | |
456 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
457 | ret = __add_prelim_ref(prefs, 0, info_key, | |
458 | *info_level + 1, offset, | |
459 | bytenr, 1); | |
460 | break; | |
461 | case BTRFS_SHARED_DATA_REF_KEY: { | |
462 | struct btrfs_shared_data_ref *sdref; | |
463 | int count; | |
464 | ||
465 | sdref = (struct btrfs_shared_data_ref *)(iref + 1); | |
466 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
467 | ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, | |
468 | bytenr, count); | |
469 | break; | |
470 | } | |
471 | case BTRFS_TREE_BLOCK_REF_KEY: | |
472 | ret = __add_prelim_ref(prefs, offset, info_key, | |
473 | *info_level + 1, 0, bytenr, 1); | |
474 | break; | |
475 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
476 | struct btrfs_extent_data_ref *dref; | |
477 | int count; | |
478 | u64 root; | |
479 | ||
480 | dref = (struct btrfs_extent_data_ref *)(&iref->offset); | |
481 | count = btrfs_extent_data_ref_count(leaf, dref); | |
482 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
483 | dref); | |
484 | key.type = BTRFS_EXTENT_DATA_KEY; | |
485 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
486 | root = btrfs_extent_data_ref_root(leaf, dref); | |
487 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr, | |
488 | count); | |
489 | break; | |
490 | } | |
491 | default: | |
492 | WARN_ON(1); | |
493 | } | |
494 | BUG_ON(ret); | |
495 | ptr += btrfs_extent_inline_ref_size(type); | |
496 | } | |
497 | ||
498 | return 0; | |
499 | } | |
500 | ||
501 | /* | |
502 | * add all non-inline backrefs for bytenr to the list | |
503 | */ | |
504 | static int __add_keyed_refs(struct btrfs_fs_info *fs_info, | |
505 | struct btrfs_path *path, u64 bytenr, | |
506 | struct btrfs_key *info_key, int info_level, | |
507 | struct list_head *prefs) | |
508 | { | |
509 | struct btrfs_root *extent_root = fs_info->extent_root; | |
510 | int ret; | |
511 | int slot; | |
512 | struct extent_buffer *leaf; | |
513 | struct btrfs_key key; | |
514 | ||
515 | while (1) { | |
516 | ret = btrfs_next_item(extent_root, path); | |
517 | if (ret < 0) | |
518 | break; | |
519 | if (ret) { | |
520 | ret = 0; | |
521 | break; | |
522 | } | |
523 | ||
524 | slot = path->slots[0]; | |
525 | leaf = path->nodes[0]; | |
526 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
527 | ||
528 | if (key.objectid != bytenr) | |
529 | break; | |
530 | if (key.type < BTRFS_TREE_BLOCK_REF_KEY) | |
531 | continue; | |
532 | if (key.type > BTRFS_SHARED_DATA_REF_KEY) | |
533 | break; | |
534 | ||
535 | switch (key.type) { | |
536 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
537 | ret = __add_prelim_ref(prefs, 0, info_key, | |
538 | info_level + 1, key.offset, | |
539 | bytenr, 1); | |
540 | break; | |
541 | case BTRFS_SHARED_DATA_REF_KEY: { | |
542 | struct btrfs_shared_data_ref *sdref; | |
543 | int count; | |
544 | ||
545 | sdref = btrfs_item_ptr(leaf, slot, | |
546 | struct btrfs_shared_data_ref); | |
547 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
548 | ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, | |
549 | bytenr, count); | |
550 | break; | |
551 | } | |
552 | case BTRFS_TREE_BLOCK_REF_KEY: | |
553 | ret = __add_prelim_ref(prefs, key.offset, info_key, | |
554 | info_level + 1, 0, bytenr, 1); | |
555 | break; | |
556 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
557 | struct btrfs_extent_data_ref *dref; | |
558 | int count; | |
559 | u64 root; | |
560 | ||
561 | dref = btrfs_item_ptr(leaf, slot, | |
562 | struct btrfs_extent_data_ref); | |
563 | count = btrfs_extent_data_ref_count(leaf, dref); | |
564 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
565 | dref); | |
566 | key.type = BTRFS_EXTENT_DATA_KEY; | |
567 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
568 | root = btrfs_extent_data_ref_root(leaf, dref); | |
569 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, | |
570 | bytenr, count); | |
571 | break; | |
572 | } | |
573 | default: | |
574 | WARN_ON(1); | |
575 | } | |
576 | BUG_ON(ret); | |
577 | } | |
578 | ||
579 | return ret; | |
580 | } | |
581 | ||
582 | /* | |
583 | * this adds all existing backrefs (inline backrefs, backrefs and delayed | |
584 | * refs) for the given bytenr to the refs list, merges duplicates and resolves | |
585 | * indirect refs to their parent bytenr. | |
586 | * When roots are found, they're added to the roots list | |
587 | * | |
588 | * FIXME some caching might speed things up | |
589 | */ | |
590 | static int find_parent_nodes(struct btrfs_trans_handle *trans, | |
591 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
592 | u64 seq, struct ulist *refs, struct ulist *roots) | |
593 | { | |
594 | struct btrfs_key key; | |
595 | struct btrfs_path *path; | |
596 | struct btrfs_key info_key = { 0 }; | |
597 | struct btrfs_delayed_ref_root *delayed_refs = NULL; | |
598 | struct btrfs_delayed_ref_head *head = NULL; | |
599 | int info_level = 0; | |
600 | int ret; | |
601 | struct list_head prefs_delayed; | |
602 | struct list_head prefs; | |
603 | struct __prelim_ref *ref; | |
604 | ||
605 | INIT_LIST_HEAD(&prefs); | |
606 | INIT_LIST_HEAD(&prefs_delayed); | |
607 | ||
608 | key.objectid = bytenr; | |
609 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
610 | key.offset = (u64)-1; | |
611 | ||
612 | path = btrfs_alloc_path(); | |
613 | if (!path) | |
614 | return -ENOMEM; | |
615 | ||
616 | /* | |
617 | * grab both a lock on the path and a lock on the delayed ref head. | |
618 | * We need both to get a consistent picture of how the refs look | |
619 | * at a specified point in time | |
620 | */ | |
621 | again: | |
622 | ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); | |
623 | if (ret < 0) | |
624 | goto out; | |
625 | BUG_ON(ret == 0); | |
626 | ||
627 | /* | |
628 | * look if there are updates for this ref queued and lock the head | |
629 | */ | |
630 | delayed_refs = &trans->transaction->delayed_refs; | |
631 | spin_lock(&delayed_refs->lock); | |
632 | head = btrfs_find_delayed_ref_head(trans, bytenr); | |
633 | if (head) { | |
634 | if (!mutex_trylock(&head->mutex)) { | |
635 | atomic_inc(&head->node.refs); | |
636 | spin_unlock(&delayed_refs->lock); | |
637 | ||
638 | btrfs_release_path(path); | |
639 | ||
640 | /* | |
641 | * Mutex was contended, block until it's | |
642 | * released and try again | |
643 | */ | |
644 | mutex_lock(&head->mutex); | |
645 | mutex_unlock(&head->mutex); | |
646 | btrfs_put_delayed_ref(&head->node); | |
647 | goto again; | |
648 | } | |
649 | ret = __add_delayed_refs(head, seq, &info_key, &prefs_delayed); | |
650 | if (ret) | |
651 | goto out; | |
652 | } | |
653 | spin_unlock(&delayed_refs->lock); | |
654 | ||
655 | if (path->slots[0]) { | |
656 | struct extent_buffer *leaf; | |
657 | int slot; | |
658 | ||
659 | leaf = path->nodes[0]; | |
660 | slot = path->slots[0] - 1; | |
661 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
662 | if (key.objectid == bytenr && | |
663 | key.type == BTRFS_EXTENT_ITEM_KEY) { | |
664 | ret = __add_inline_refs(fs_info, path, bytenr, | |
665 | &info_key, &info_level, &prefs); | |
666 | if (ret) | |
667 | goto out; | |
668 | ret = __add_keyed_refs(fs_info, path, bytenr, &info_key, | |
669 | info_level, &prefs); | |
670 | if (ret) | |
671 | goto out; | |
672 | } | |
673 | } | |
674 | btrfs_release_path(path); | |
675 | ||
676 | /* | |
677 | * when adding the delayed refs above, the info_key might not have | |
678 | * been known yet. Go over the list and replace the missing keys | |
679 | */ | |
680 | list_for_each_entry(ref, &prefs_delayed, list) { | |
681 | if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0) | |
682 | memcpy(&ref->key, &info_key, sizeof(ref->key)); | |
683 | } | |
684 | list_splice_init(&prefs_delayed, &prefs); | |
685 | ||
686 | ret = __merge_refs(&prefs, 1); | |
687 | if (ret) | |
688 | goto out; | |
689 | ||
690 | ret = __resolve_indirect_refs(fs_info, &prefs); | |
691 | if (ret) | |
692 | goto out; | |
693 | ||
694 | ret = __merge_refs(&prefs, 2); | |
695 | if (ret) | |
696 | goto out; | |
697 | ||
698 | while (!list_empty(&prefs)) { | |
699 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
700 | list_del(&ref->list); | |
701 | if (ref->count < 0) | |
702 | WARN_ON(1); | |
703 | if (ref->count && ref->root_id && ref->parent == 0) { | |
704 | /* no parent == root of tree */ | |
705 | ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); | |
706 | BUG_ON(ret < 0); | |
707 | } | |
708 | if (ref->count && ref->parent) { | |
709 | ret = ulist_add(refs, ref->parent, 0, GFP_NOFS); | |
710 | BUG_ON(ret < 0); | |
711 | } | |
712 | kfree(ref); | |
713 | } | |
714 | ||
715 | out: | |
716 | if (head) | |
717 | mutex_unlock(&head->mutex); | |
718 | btrfs_free_path(path); | |
719 | while (!list_empty(&prefs)) { | |
720 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
721 | list_del(&ref->list); | |
722 | kfree(ref); | |
723 | } | |
724 | while (!list_empty(&prefs_delayed)) { | |
725 | ref = list_first_entry(&prefs_delayed, struct __prelim_ref, | |
726 | list); | |
727 | list_del(&ref->list); | |
728 | kfree(ref); | |
729 | } | |
730 | ||
731 | return ret; | |
732 | } | |
733 | ||
734 | /* | |
735 | * Finds all leafs with a reference to the specified combination of bytenr and | |
736 | * offset. key_list_head will point to a list of corresponding keys (caller must | |
737 | * free each list element). The leafs will be stored in the leafs ulist, which | |
738 | * must be freed with ulist_free. | |
739 | * | |
740 | * returns 0 on success, <0 on error | |
741 | */ | |
742 | static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, | |
743 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
744 | u64 num_bytes, u64 seq, struct ulist **leafs) | |
745 | { | |
746 | struct ulist *tmp; | |
747 | int ret; | |
748 | ||
749 | tmp = ulist_alloc(GFP_NOFS); | |
750 | if (!tmp) | |
751 | return -ENOMEM; | |
752 | *leafs = ulist_alloc(GFP_NOFS); | |
753 | if (!*leafs) { | |
754 | ulist_free(tmp); | |
755 | return -ENOMEM; | |
756 | } | |
757 | ||
758 | ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp); | |
759 | ulist_free(tmp); | |
760 | ||
761 | if (ret < 0 && ret != -ENOENT) { | |
762 | ulist_free(*leafs); | |
763 | return ret; | |
764 | } | |
765 | ||
766 | return 0; | |
767 | } | |
768 | ||
769 | /* | |
770 | * walk all backrefs for a given extent to find all roots that reference this | |
771 | * extent. Walking a backref means finding all extents that reference this | |
772 | * extent and in turn walk the backrefs of those, too. Naturally this is a | |
773 | * recursive process, but here it is implemented in an iterative fashion: We | |
774 | * find all referencing extents for the extent in question and put them on a | |
775 | * list. In turn, we find all referencing extents for those, further appending | |
776 | * to the list. The way we iterate the list allows adding more elements after | |
777 | * the current while iterating. The process stops when we reach the end of the | |
778 | * list. Found roots are added to the roots list. | |
779 | * | |
780 | * returns 0 on success, < 0 on error. | |
781 | */ | |
782 | int btrfs_find_all_roots(struct btrfs_trans_handle *trans, | |
783 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
784 | u64 num_bytes, u64 seq, struct ulist **roots) | |
785 | { | |
786 | struct ulist *tmp; | |
787 | struct ulist_node *node = NULL; | |
788 | int ret; | |
789 | ||
790 | tmp = ulist_alloc(GFP_NOFS); | |
791 | if (!tmp) | |
792 | return -ENOMEM; | |
793 | *roots = ulist_alloc(GFP_NOFS); | |
794 | if (!*roots) { | |
795 | ulist_free(tmp); | |
796 | return -ENOMEM; | |
797 | } | |
798 | ||
799 | while (1) { | |
800 | ret = find_parent_nodes(trans, fs_info, bytenr, seq, | |
801 | tmp, *roots); | |
802 | if (ret < 0 && ret != -ENOENT) { | |
803 | ulist_free(tmp); | |
804 | ulist_free(*roots); | |
805 | return ret; | |
806 | } | |
807 | node = ulist_next(tmp, node); | |
808 | if (!node) | |
809 | break; | |
810 | bytenr = node->val; | |
811 | } | |
812 | ||
813 | ulist_free(tmp); | |
814 | return 0; | |
815 | } | |
816 | ||
817 | ||
a542ad1b JS |
818 | static int __inode_info(u64 inum, u64 ioff, u8 key_type, |
819 | struct btrfs_root *fs_root, struct btrfs_path *path, | |
820 | struct btrfs_key *found_key) | |
821 | { | |
822 | int ret; | |
823 | struct btrfs_key key; | |
824 | struct extent_buffer *eb; | |
825 | ||
826 | key.type = key_type; | |
827 | key.objectid = inum; | |
828 | key.offset = ioff; | |
829 | ||
830 | ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); | |
831 | if (ret < 0) | |
832 | return ret; | |
833 | ||
834 | eb = path->nodes[0]; | |
835 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { | |
836 | ret = btrfs_next_leaf(fs_root, path); | |
837 | if (ret) | |
838 | return ret; | |
839 | eb = path->nodes[0]; | |
840 | } | |
841 | ||
842 | btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); | |
843 | if (found_key->type != key.type || found_key->objectid != key.objectid) | |
844 | return 1; | |
845 | ||
846 | return 0; | |
847 | } | |
848 | ||
849 | /* | |
850 | * this makes the path point to (inum INODE_ITEM ioff) | |
851 | */ | |
852 | int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
853 | struct btrfs_path *path) | |
854 | { | |
855 | struct btrfs_key key; | |
856 | return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, | |
857 | &key); | |
858 | } | |
859 | ||
860 | static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
861 | struct btrfs_path *path, | |
862 | struct btrfs_key *found_key) | |
863 | { | |
864 | return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, | |
865 | found_key); | |
866 | } | |
867 | ||
868 | /* | |
869 | * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements | |
870 | * of the path are separated by '/' and the path is guaranteed to be | |
871 | * 0-terminated. the path is only given within the current file system. | |
872 | * Therefore, it never starts with a '/'. the caller is responsible to provide | |
873 | * "size" bytes in "dest". the dest buffer will be filled backwards. finally, | |
874 | * the start point of the resulting string is returned. this pointer is within | |
875 | * dest, normally. | |
876 | * in case the path buffer would overflow, the pointer is decremented further | |
877 | * as if output was written to the buffer, though no more output is actually | |
878 | * generated. that way, the caller can determine how much space would be | |
879 | * required for the path to fit into the buffer. in that case, the returned | |
880 | * value will be smaller than dest. callers must check this! | |
881 | */ | |
882 | static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, | |
883 | struct btrfs_inode_ref *iref, | |
884 | struct extent_buffer *eb_in, u64 parent, | |
885 | char *dest, u32 size) | |
886 | { | |
887 | u32 len; | |
888 | int slot; | |
889 | u64 next_inum; | |
890 | int ret; | |
891 | s64 bytes_left = size - 1; | |
892 | struct extent_buffer *eb = eb_in; | |
893 | struct btrfs_key found_key; | |
894 | ||
895 | if (bytes_left >= 0) | |
896 | dest[bytes_left] = '\0'; | |
897 | ||
898 | while (1) { | |
899 | len = btrfs_inode_ref_name_len(eb, iref); | |
900 | bytes_left -= len; | |
901 | if (bytes_left >= 0) | |
902 | read_extent_buffer(eb, dest + bytes_left, | |
903 | (unsigned long)(iref + 1), len); | |
904 | if (eb != eb_in) | |
905 | free_extent_buffer(eb); | |
906 | ret = inode_ref_info(parent, 0, fs_root, path, &found_key); | |
907 | if (ret) | |
908 | break; | |
909 | next_inum = found_key.offset; | |
910 | ||
911 | /* regular exit ahead */ | |
912 | if (parent == next_inum) | |
913 | break; | |
914 | ||
915 | slot = path->slots[0]; | |
916 | eb = path->nodes[0]; | |
917 | /* make sure we can use eb after releasing the path */ | |
918 | if (eb != eb_in) | |
919 | atomic_inc(&eb->refs); | |
920 | btrfs_release_path(path); | |
921 | ||
922 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
923 | parent = next_inum; | |
924 | --bytes_left; | |
925 | if (bytes_left >= 0) | |
926 | dest[bytes_left] = '/'; | |
927 | } | |
928 | ||
929 | btrfs_release_path(path); | |
930 | ||
931 | if (ret) | |
932 | return ERR_PTR(ret); | |
933 | ||
934 | return dest + bytes_left; | |
935 | } | |
936 | ||
937 | /* | |
938 | * this makes the path point to (logical EXTENT_ITEM *) | |
939 | * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for | |
940 | * tree blocks and <0 on error. | |
941 | */ | |
942 | int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, | |
943 | struct btrfs_path *path, struct btrfs_key *found_key) | |
944 | { | |
945 | int ret; | |
946 | u64 flags; | |
947 | u32 item_size; | |
948 | struct extent_buffer *eb; | |
949 | struct btrfs_extent_item *ei; | |
950 | struct btrfs_key key; | |
951 | ||
952 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
953 | key.objectid = logical; | |
954 | key.offset = (u64)-1; | |
955 | ||
956 | ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); | |
957 | if (ret < 0) | |
958 | return ret; | |
959 | ret = btrfs_previous_item(fs_info->extent_root, path, | |
960 | 0, BTRFS_EXTENT_ITEM_KEY); | |
961 | if (ret < 0) | |
962 | return ret; | |
963 | ||
964 | btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); | |
965 | if (found_key->type != BTRFS_EXTENT_ITEM_KEY || | |
966 | found_key->objectid > logical || | |
967 | found_key->objectid + found_key->offset <= logical) | |
968 | return -ENOENT; | |
969 | ||
970 | eb = path->nodes[0]; | |
971 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
972 | BUG_ON(item_size < sizeof(*ei)); | |
973 | ||
974 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
975 | flags = btrfs_extent_flags(eb, ei); | |
976 | ||
977 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) | |
978 | return BTRFS_EXTENT_FLAG_TREE_BLOCK; | |
979 | if (flags & BTRFS_EXTENT_FLAG_DATA) | |
980 | return BTRFS_EXTENT_FLAG_DATA; | |
981 | ||
982 | return -EIO; | |
983 | } | |
984 | ||
985 | /* | |
986 | * helper function to iterate extent inline refs. ptr must point to a 0 value | |
987 | * for the first call and may be modified. it is used to track state. | |
988 | * if more refs exist, 0 is returned and the next call to | |
989 | * __get_extent_inline_ref must pass the modified ptr parameter to get the | |
990 | * next ref. after the last ref was processed, 1 is returned. | |
991 | * returns <0 on error | |
992 | */ | |
993 | static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, | |
994 | struct btrfs_extent_item *ei, u32 item_size, | |
995 | struct btrfs_extent_inline_ref **out_eiref, | |
996 | int *out_type) | |
997 | { | |
998 | unsigned long end; | |
999 | u64 flags; | |
1000 | struct btrfs_tree_block_info *info; | |
1001 | ||
1002 | if (!*ptr) { | |
1003 | /* first call */ | |
1004 | flags = btrfs_extent_flags(eb, ei); | |
1005 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
1006 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1007 | *out_eiref = | |
1008 | (struct btrfs_extent_inline_ref *)(info + 1); | |
1009 | } else { | |
1010 | *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); | |
1011 | } | |
1012 | *ptr = (unsigned long)*out_eiref; | |
1013 | if ((void *)*ptr >= (void *)ei + item_size) | |
1014 | return -ENOENT; | |
1015 | } | |
1016 | ||
1017 | end = (unsigned long)ei + item_size; | |
1018 | *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; | |
1019 | *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); | |
1020 | ||
1021 | *ptr += btrfs_extent_inline_ref_size(*out_type); | |
1022 | WARN_ON(*ptr > end); | |
1023 | if (*ptr == end) | |
1024 | return 1; /* last */ | |
1025 | ||
1026 | return 0; | |
1027 | } | |
1028 | ||
1029 | /* | |
1030 | * reads the tree block backref for an extent. tree level and root are returned | |
1031 | * through out_level and out_root. ptr must point to a 0 value for the first | |
1032 | * call and may be modified (see __get_extent_inline_ref comment). | |
1033 | * returns 0 if data was provided, 1 if there was no more data to provide or | |
1034 | * <0 on error. | |
1035 | */ | |
1036 | int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, | |
1037 | struct btrfs_extent_item *ei, u32 item_size, | |
1038 | u64 *out_root, u8 *out_level) | |
1039 | { | |
1040 | int ret; | |
1041 | int type; | |
1042 | struct btrfs_tree_block_info *info; | |
1043 | struct btrfs_extent_inline_ref *eiref; | |
1044 | ||
1045 | if (*ptr == (unsigned long)-1) | |
1046 | return 1; | |
1047 | ||
1048 | while (1) { | |
1049 | ret = __get_extent_inline_ref(ptr, eb, ei, item_size, | |
1050 | &eiref, &type); | |
1051 | if (ret < 0) | |
1052 | return ret; | |
1053 | ||
1054 | if (type == BTRFS_TREE_BLOCK_REF_KEY || | |
1055 | type == BTRFS_SHARED_BLOCK_REF_KEY) | |
1056 | break; | |
1057 | ||
1058 | if (ret == 1) | |
1059 | return 1; | |
1060 | } | |
1061 | ||
1062 | /* we can treat both ref types equally here */ | |
1063 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1064 | *out_root = btrfs_extent_inline_ref_offset(eb, eiref); | |
1065 | *out_level = btrfs_tree_block_level(eb, info); | |
1066 | ||
1067 | if (ret == 1) | |
1068 | *ptr = (unsigned long)-1; | |
1069 | ||
1070 | return 0; | |
1071 | } | |
1072 | ||
1073 | static int __data_list_add(struct list_head *head, u64 inum, | |
1074 | u64 extent_data_item_offset, u64 root) | |
1075 | { | |
1076 | struct __data_ref *ref; | |
1077 | ||
1078 | ref = kmalloc(sizeof(*ref), GFP_NOFS); | |
1079 | if (!ref) | |
1080 | return -ENOMEM; | |
1081 | ||
1082 | ref->inum = inum; | |
1083 | ref->extent_data_item_offset = extent_data_item_offset; | |
1084 | ref->root = root; | |
1085 | list_add_tail(&ref->list, head); | |
1086 | ||
1087 | return 0; | |
1088 | } | |
1089 | ||
1090 | static int __data_list_add_eb(struct list_head *head, struct extent_buffer *eb, | |
1091 | struct btrfs_extent_data_ref *dref) | |
1092 | { | |
1093 | return __data_list_add(head, btrfs_extent_data_ref_objectid(eb, dref), | |
1094 | btrfs_extent_data_ref_offset(eb, dref), | |
1095 | btrfs_extent_data_ref_root(eb, dref)); | |
1096 | } | |
1097 | ||
1098 | static int __shared_list_add(struct list_head *head, u64 disk_byte) | |
1099 | { | |
1100 | struct __shared_ref *ref; | |
1101 | ||
1102 | ref = kmalloc(sizeof(*ref), GFP_NOFS); | |
1103 | if (!ref) | |
1104 | return -ENOMEM; | |
1105 | ||
1106 | ref->disk_byte = disk_byte; | |
1107 | list_add_tail(&ref->list, head); | |
1108 | ||
1109 | return 0; | |
1110 | } | |
1111 | ||
1112 | static int __iter_shared_inline_ref_inodes(struct btrfs_fs_info *fs_info, | |
1113 | u64 logical, u64 inum, | |
1114 | u64 extent_data_item_offset, | |
1115 | u64 extent_offset, | |
1116 | struct btrfs_path *path, | |
1117 | struct list_head *data_refs, | |
1118 | iterate_extent_inodes_t *iterate, | |
1119 | void *ctx) | |
1120 | { | |
1121 | u64 ref_root; | |
1122 | u32 item_size; | |
1123 | struct btrfs_key key; | |
1124 | struct extent_buffer *eb; | |
1125 | struct btrfs_extent_item *ei; | |
1126 | struct btrfs_extent_inline_ref *eiref; | |
1127 | struct __data_ref *ref; | |
1128 | int ret; | |
1129 | int type; | |
1130 | int last; | |
1131 | unsigned long ptr = 0; | |
1132 | ||
1133 | WARN_ON(!list_empty(data_refs)); | |
1134 | ret = extent_from_logical(fs_info, logical, path, &key); | |
1135 | if (ret & BTRFS_EXTENT_FLAG_DATA) | |
1136 | ret = -EIO; | |
1137 | if (ret < 0) | |
1138 | goto out; | |
1139 | ||
1140 | eb = path->nodes[0]; | |
1141 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
1142 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
1143 | ||
1144 | ret = 0; | |
1145 | ref_root = 0; | |
1146 | /* | |
1147 | * as done in iterate_extent_inodes, we first build a list of refs to | |
1148 | * iterate, then free the path and then iterate them to avoid deadlocks. | |
1149 | */ | |
1150 | do { | |
1151 | last = __get_extent_inline_ref(&ptr, eb, ei, item_size, | |
1152 | &eiref, &type); | |
1153 | if (last < 0) { | |
1154 | ret = last; | |
1155 | goto out; | |
1156 | } | |
1157 | if (type == BTRFS_TREE_BLOCK_REF_KEY || | |
1158 | type == BTRFS_SHARED_BLOCK_REF_KEY) { | |
1159 | ref_root = btrfs_extent_inline_ref_offset(eb, eiref); | |
1160 | ret = __data_list_add(data_refs, inum, | |
1161 | extent_data_item_offset, | |
1162 | ref_root); | |
1163 | } | |
1164 | } while (!ret && !last); | |
1165 | ||
1166 | btrfs_release_path(path); | |
1167 | ||
1168 | if (ref_root == 0) { | |
1169 | printk(KERN_ERR "btrfs: failed to find tree block ref " | |
1170 | "for shared data backref %llu\n", logical); | |
1171 | WARN_ON(1); | |
1172 | ret = -EIO; | |
1173 | } | |
1174 | ||
1175 | out: | |
1176 | while (!list_empty(data_refs)) { | |
1177 | ref = list_first_entry(data_refs, struct __data_ref, list); | |
1178 | list_del(&ref->list); | |
1179 | if (!ret) | |
1180 | ret = iterate(ref->inum, extent_offset + | |
1181 | ref->extent_data_item_offset, | |
1182 | ref->root, ctx); | |
1183 | kfree(ref); | |
1184 | } | |
1185 | ||
1186 | return ret; | |
1187 | } | |
1188 | ||
1189 | static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info, | |
1190 | u64 logical, u64 orig_extent_item_objectid, | |
1191 | u64 extent_offset, struct btrfs_path *path, | |
1192 | struct list_head *data_refs, | |
1193 | iterate_extent_inodes_t *iterate, | |
1194 | void *ctx) | |
1195 | { | |
1196 | u64 disk_byte; | |
1197 | struct btrfs_key key; | |
1198 | struct btrfs_file_extent_item *fi; | |
1199 | struct extent_buffer *eb; | |
1200 | int slot; | |
1201 | int nritems; | |
1202 | int ret; | |
1203 | int found = 0; | |
1204 | ||
1205 | eb = read_tree_block(fs_info->tree_root, logical, | |
1206 | fs_info->tree_root->leafsize, 0); | |
1207 | if (!eb) | |
1208 | return -EIO; | |
1209 | ||
1210 | /* | |
1211 | * from the shared data ref, we only have the leaf but we need | |
1212 | * the key. thus, we must look into all items and see that we | |
1213 | * find one (some) with a reference to our extent item. | |
1214 | */ | |
1215 | nritems = btrfs_header_nritems(eb); | |
1216 | for (slot = 0; slot < nritems; ++slot) { | |
1217 | btrfs_item_key_to_cpu(eb, &key, slot); | |
1218 | if (key.type != BTRFS_EXTENT_DATA_KEY) | |
1219 | continue; | |
1220 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
1221 | if (!fi) { | |
1222 | free_extent_buffer(eb); | |
1223 | return -EIO; | |
1224 | } | |
1225 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
1226 | if (disk_byte != orig_extent_item_objectid) { | |
1227 | if (found) | |
1228 | break; | |
1229 | else | |
1230 | continue; | |
1231 | } | |
1232 | ++found; | |
1233 | ret = __iter_shared_inline_ref_inodes(fs_info, logical, | |
1234 | key.objectid, | |
1235 | key.offset, | |
1236 | extent_offset, path, | |
1237 | data_refs, | |
1238 | iterate, ctx); | |
1239 | if (ret) | |
1240 | break; | |
1241 | } | |
1242 | ||
1243 | if (!found) { | |
1244 | printk(KERN_ERR "btrfs: failed to follow shared data backref " | |
1245 | "to parent %llu\n", logical); | |
1246 | WARN_ON(1); | |
1247 | ret = -EIO; | |
1248 | } | |
1249 | ||
1250 | free_extent_buffer(eb); | |
1251 | return ret; | |
1252 | } | |
1253 | ||
1254 | /* | |
1255 | * calls iterate() for every inode that references the extent identified by | |
1256 | * the given parameters. will use the path given as a parameter and return it | |
1257 | * released. | |
1258 | * when the iterator function returns a non-zero value, iteration stops. | |
1259 | */ | |
1260 | int iterate_extent_inodes(struct btrfs_fs_info *fs_info, | |
1261 | struct btrfs_path *path, | |
1262 | u64 extent_item_objectid, | |
1263 | u64 extent_offset, | |
1264 | iterate_extent_inodes_t *iterate, void *ctx) | |
1265 | { | |
1266 | unsigned long ptr = 0; | |
1267 | int last; | |
1268 | int ret; | |
1269 | int type; | |
1270 | u64 logical; | |
1271 | u32 item_size; | |
1272 | struct btrfs_extent_inline_ref *eiref; | |
1273 | struct btrfs_extent_data_ref *dref; | |
1274 | struct extent_buffer *eb; | |
1275 | struct btrfs_extent_item *ei; | |
1276 | struct btrfs_key key; | |
1277 | struct list_head data_refs = LIST_HEAD_INIT(data_refs); | |
1278 | struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); | |
1279 | struct __data_ref *ref_d; | |
1280 | struct __shared_ref *ref_s; | |
1281 | ||
1282 | eb = path->nodes[0]; | |
1283 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
1284 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
1285 | ||
1286 | /* first we iterate the inline refs, ... */ | |
1287 | do { | |
1288 | last = __get_extent_inline_ref(&ptr, eb, ei, item_size, | |
1289 | &eiref, &type); | |
1290 | if (last == -ENOENT) { | |
1291 | ret = 0; | |
1292 | break; | |
1293 | } | |
1294 | if (last < 0) { | |
1295 | ret = last; | |
1296 | break; | |
1297 | } | |
1298 | ||
1299 | if (type == BTRFS_EXTENT_DATA_REF_KEY) { | |
1300 | dref = (struct btrfs_extent_data_ref *)(&eiref->offset); | |
1301 | ret = __data_list_add_eb(&data_refs, eb, dref); | |
1302 | } else if (type == BTRFS_SHARED_DATA_REF_KEY) { | |
1303 | logical = btrfs_extent_inline_ref_offset(eb, eiref); | |
1304 | ret = __shared_list_add(&shared_refs, logical); | |
1305 | } | |
1306 | } while (!ret && !last); | |
1307 | ||
1308 | /* ... then we proceed to in-tree references and ... */ | |
1309 | while (!ret) { | |
1310 | ++path->slots[0]; | |
1311 | if (path->slots[0] > btrfs_header_nritems(eb)) { | |
1312 | ret = btrfs_next_leaf(fs_info->extent_root, path); | |
1313 | if (ret) { | |
1314 | if (ret == 1) | |
1315 | ret = 0; /* we're done */ | |
1316 | break; | |
1317 | } | |
1318 | eb = path->nodes[0]; | |
1319 | } | |
1320 | btrfs_item_key_to_cpu(eb, &key, path->slots[0]); | |
1321 | if (key.objectid != extent_item_objectid) | |
1322 | break; | |
1323 | if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { | |
1324 | dref = btrfs_item_ptr(eb, path->slots[0], | |
1325 | struct btrfs_extent_data_ref); | |
1326 | ret = __data_list_add_eb(&data_refs, eb, dref); | |
1327 | } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) { | |
1328 | ret = __shared_list_add(&shared_refs, key.offset); | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | btrfs_release_path(path); | |
1333 | ||
1334 | /* | |
1335 | * ... only at the very end we can process the refs we found. this is | |
1336 | * because the iterator function we call is allowed to make tree lookups | |
1337 | * and we have to avoid deadlocks. additionally, we need more tree | |
1338 | * lookups ourselves for shared data refs. | |
1339 | */ | |
1340 | while (!list_empty(&data_refs)) { | |
1341 | ref_d = list_first_entry(&data_refs, struct __data_ref, list); | |
1342 | list_del(&ref_d->list); | |
1343 | if (!ret) | |
1344 | ret = iterate(ref_d->inum, extent_offset + | |
1345 | ref_d->extent_data_item_offset, | |
1346 | ref_d->root, ctx); | |
1347 | kfree(ref_d); | |
1348 | } | |
1349 | ||
1350 | while (!list_empty(&shared_refs)) { | |
1351 | ref_s = list_first_entry(&shared_refs, struct __shared_ref, | |
1352 | list); | |
1353 | list_del(&ref_s->list); | |
1354 | if (!ret) | |
1355 | ret = __iter_shared_inline_ref(fs_info, | |
1356 | ref_s->disk_byte, | |
1357 | extent_item_objectid, | |
1358 | extent_offset, path, | |
1359 | &data_refs, | |
1360 | iterate, ctx); | |
1361 | kfree(ref_s); | |
1362 | } | |
1363 | ||
1364 | return ret; | |
1365 | } | |
1366 | ||
1367 | int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, | |
1368 | struct btrfs_path *path, | |
1369 | iterate_extent_inodes_t *iterate, void *ctx) | |
1370 | { | |
1371 | int ret; | |
1372 | u64 offset; | |
1373 | struct btrfs_key found_key; | |
1374 | ||
1375 | ret = extent_from_logical(fs_info, logical, path, | |
1376 | &found_key); | |
1377 | if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) | |
1378 | ret = -EINVAL; | |
1379 | if (ret < 0) | |
1380 | return ret; | |
1381 | ||
1382 | offset = logical - found_key.objectid; | |
1383 | ret = iterate_extent_inodes(fs_info, path, found_key.objectid, | |
1384 | offset, iterate, ctx); | |
1385 | ||
1386 | return ret; | |
1387 | } | |
1388 | ||
1389 | static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, | |
1390 | struct btrfs_path *path, | |
1391 | iterate_irefs_t *iterate, void *ctx) | |
1392 | { | |
1393 | int ret; | |
1394 | int slot; | |
1395 | u32 cur; | |
1396 | u32 len; | |
1397 | u32 name_len; | |
1398 | u64 parent = 0; | |
1399 | int found = 0; | |
1400 | struct extent_buffer *eb; | |
1401 | struct btrfs_item *item; | |
1402 | struct btrfs_inode_ref *iref; | |
1403 | struct btrfs_key found_key; | |
1404 | ||
1405 | while (1) { | |
1406 | ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, | |
1407 | &found_key); | |
1408 | if (ret < 0) | |
1409 | break; | |
1410 | if (ret) { | |
1411 | ret = found ? 0 : -ENOENT; | |
1412 | break; | |
1413 | } | |
1414 | ++found; | |
1415 | ||
1416 | parent = found_key.offset; | |
1417 | slot = path->slots[0]; | |
1418 | eb = path->nodes[0]; | |
1419 | /* make sure we can use eb after releasing the path */ | |
1420 | atomic_inc(&eb->refs); | |
1421 | btrfs_release_path(path); | |
1422 | ||
1423 | item = btrfs_item_nr(eb, slot); | |
1424 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
1425 | ||
1426 | for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { | |
1427 | name_len = btrfs_inode_ref_name_len(eb, iref); | |
1428 | /* path must be released before calling iterate()! */ | |
1429 | ret = iterate(parent, iref, eb, ctx); | |
1430 | if (ret) { | |
1431 | free_extent_buffer(eb); | |
1432 | break; | |
1433 | } | |
1434 | len = sizeof(*iref) + name_len; | |
1435 | iref = (struct btrfs_inode_ref *)((char *)iref + len); | |
1436 | } | |
1437 | free_extent_buffer(eb); | |
1438 | } | |
1439 | ||
1440 | btrfs_release_path(path); | |
1441 | ||
1442 | return ret; | |
1443 | } | |
1444 | ||
1445 | /* | |
1446 | * returns 0 if the path could be dumped (probably truncated) | |
1447 | * returns <0 in case of an error | |
1448 | */ | |
1449 | static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref, | |
1450 | struct extent_buffer *eb, void *ctx) | |
1451 | { | |
1452 | struct inode_fs_paths *ipath = ctx; | |
1453 | char *fspath; | |
1454 | char *fspath_min; | |
1455 | int i = ipath->fspath->elem_cnt; | |
1456 | const int s_ptr = sizeof(char *); | |
1457 | u32 bytes_left; | |
1458 | ||
1459 | bytes_left = ipath->fspath->bytes_left > s_ptr ? | |
1460 | ipath->fspath->bytes_left - s_ptr : 0; | |
1461 | ||
740c3d22 | 1462 | fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
a542ad1b JS |
1463 | fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb, |
1464 | inum, fspath_min, bytes_left); | |
1465 | if (IS_ERR(fspath)) | |
1466 | return PTR_ERR(fspath); | |
1467 | ||
1468 | if (fspath > fspath_min) { | |
745c4d8e | 1469 | ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
a542ad1b JS |
1470 | ++ipath->fspath->elem_cnt; |
1471 | ipath->fspath->bytes_left = fspath - fspath_min; | |
1472 | } else { | |
1473 | ++ipath->fspath->elem_missed; | |
1474 | ipath->fspath->bytes_missing += fspath_min - fspath; | |
1475 | ipath->fspath->bytes_left = 0; | |
1476 | } | |
1477 | ||
1478 | return 0; | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * this dumps all file system paths to the inode into the ipath struct, provided | |
1483 | * is has been created large enough. each path is zero-terminated and accessed | |
740c3d22 | 1484 | * from ipath->fspath->val[i]. |
a542ad1b | 1485 | * when it returns, there are ipath->fspath->elem_cnt number of paths available |
740c3d22 | 1486 | * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
a542ad1b JS |
1487 | * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, |
1488 | * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would | |
1489 | * have been needed to return all paths. | |
1490 | */ | |
1491 | int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) | |
1492 | { | |
1493 | return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, | |
1494 | inode_to_path, ipath); | |
1495 | } | |
1496 | ||
1497 | /* | |
1498 | * allocates space to return multiple file system paths for an inode. | |
1499 | * total_bytes to allocate are passed, note that space usable for actual path | |
1500 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1501 | * the returned pointer must be freed with free_ipath() in the end. | |
1502 | */ | |
1503 | struct btrfs_data_container *init_data_container(u32 total_bytes) | |
1504 | { | |
1505 | struct btrfs_data_container *data; | |
1506 | size_t alloc_bytes; | |
1507 | ||
1508 | alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); | |
1509 | data = kmalloc(alloc_bytes, GFP_NOFS); | |
1510 | if (!data) | |
1511 | return ERR_PTR(-ENOMEM); | |
1512 | ||
1513 | if (total_bytes >= sizeof(*data)) { | |
1514 | data->bytes_left = total_bytes - sizeof(*data); | |
1515 | data->bytes_missing = 0; | |
1516 | } else { | |
1517 | data->bytes_missing = sizeof(*data) - total_bytes; | |
1518 | data->bytes_left = 0; | |
1519 | } | |
1520 | ||
1521 | data->elem_cnt = 0; | |
1522 | data->elem_missed = 0; | |
1523 | ||
1524 | return data; | |
1525 | } | |
1526 | ||
1527 | /* | |
1528 | * allocates space to return multiple file system paths for an inode. | |
1529 | * total_bytes to allocate are passed, note that space usable for actual path | |
1530 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1531 | * the returned pointer must be freed with free_ipath() in the end. | |
1532 | */ | |
1533 | struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, | |
1534 | struct btrfs_path *path) | |
1535 | { | |
1536 | struct inode_fs_paths *ifp; | |
1537 | struct btrfs_data_container *fspath; | |
1538 | ||
1539 | fspath = init_data_container(total_bytes); | |
1540 | if (IS_ERR(fspath)) | |
1541 | return (void *)fspath; | |
1542 | ||
1543 | ifp = kmalloc(sizeof(*ifp), GFP_NOFS); | |
1544 | if (!ifp) { | |
1545 | kfree(fspath); | |
1546 | return ERR_PTR(-ENOMEM); | |
1547 | } | |
1548 | ||
1549 | ifp->btrfs_path = path; | |
1550 | ifp->fspath = fspath; | |
1551 | ifp->fs_root = fs_root; | |
1552 | ||
1553 | return ifp; | |
1554 | } | |
1555 | ||
1556 | void free_ipath(struct inode_fs_paths *ipath) | |
1557 | { | |
1558 | kfree(ipath); | |
1559 | } |