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a542ad1b JS |
1 | /* |
2 | * Copyright (C) 2011 STRATO. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include "ctree.h" | |
20 | #include "disk-io.h" | |
21 | #include "backref.h" | |
8da6d581 JS |
22 | #include "ulist.h" |
23 | #include "transaction.h" | |
24 | #include "delayed-ref.h" | |
b916a59a | 25 | #include "locking.h" |
a542ad1b | 26 | |
976b1908 JS |
27 | struct extent_inode_elem { |
28 | u64 inum; | |
29 | u64 offset; | |
30 | struct extent_inode_elem *next; | |
31 | }; | |
32 | ||
33 | static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, | |
34 | struct btrfs_file_extent_item *fi, | |
35 | u64 extent_item_pos, | |
36 | struct extent_inode_elem **eie) | |
37 | { | |
38 | u64 data_offset; | |
39 | u64 data_len; | |
40 | struct extent_inode_elem *e; | |
41 | ||
42 | data_offset = btrfs_file_extent_offset(eb, fi); | |
43 | data_len = btrfs_file_extent_num_bytes(eb, fi); | |
44 | ||
45 | if (extent_item_pos < data_offset || | |
46 | extent_item_pos >= data_offset + data_len) | |
47 | return 1; | |
48 | ||
49 | e = kmalloc(sizeof(*e), GFP_NOFS); | |
50 | if (!e) | |
51 | return -ENOMEM; | |
52 | ||
53 | e->next = *eie; | |
54 | e->inum = key->objectid; | |
55 | e->offset = key->offset + (extent_item_pos - data_offset); | |
56 | *eie = e; | |
57 | ||
58 | return 0; | |
59 | } | |
60 | ||
61 | static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte, | |
62 | u64 extent_item_pos, | |
63 | struct extent_inode_elem **eie) | |
64 | { | |
65 | u64 disk_byte; | |
66 | struct btrfs_key key; | |
67 | struct btrfs_file_extent_item *fi; | |
68 | int slot; | |
69 | int nritems; | |
70 | int extent_type; | |
71 | int ret; | |
72 | ||
73 | /* | |
74 | * from the shared data ref, we only have the leaf but we need | |
75 | * the key. thus, we must look into all items and see that we | |
76 | * find one (some) with a reference to our extent item. | |
77 | */ | |
78 | nritems = btrfs_header_nritems(eb); | |
79 | for (slot = 0; slot < nritems; ++slot) { | |
80 | btrfs_item_key_to_cpu(eb, &key, slot); | |
81 | if (key.type != BTRFS_EXTENT_DATA_KEY) | |
82 | continue; | |
83 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
84 | extent_type = btrfs_file_extent_type(eb, fi); | |
85 | if (extent_type == BTRFS_FILE_EXTENT_INLINE) | |
86 | continue; | |
87 | /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ | |
88 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
89 | if (disk_byte != wanted_disk_byte) | |
90 | continue; | |
91 | ||
92 | ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie); | |
93 | if (ret < 0) | |
94 | return ret; | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
8da6d581 JS |
100 | /* |
101 | * this structure records all encountered refs on the way up to the root | |
102 | */ | |
103 | struct __prelim_ref { | |
104 | struct list_head list; | |
105 | u64 root_id; | |
d5c88b73 | 106 | struct btrfs_key key_for_search; |
8da6d581 JS |
107 | int level; |
108 | int count; | |
3301958b | 109 | struct extent_inode_elem *inode_list; |
8da6d581 JS |
110 | u64 parent; |
111 | u64 wanted_disk_byte; | |
112 | }; | |
113 | ||
d5c88b73 JS |
114 | /* |
115 | * the rules for all callers of this function are: | |
116 | * - obtaining the parent is the goal | |
117 | * - if you add a key, you must know that it is a correct key | |
118 | * - if you cannot add the parent or a correct key, then we will look into the | |
119 | * block later to set a correct key | |
120 | * | |
121 | * delayed refs | |
122 | * ============ | |
123 | * backref type | shared | indirect | shared | indirect | |
124 | * information | tree | tree | data | data | |
125 | * --------------------+--------+----------+--------+---------- | |
126 | * parent logical | y | - | - | - | |
127 | * key to resolve | - | y | y | y | |
128 | * tree block logical | - | - | - | - | |
129 | * root for resolving | y | y | y | y | |
130 | * | |
131 | * - column 1: we've the parent -> done | |
132 | * - column 2, 3, 4: we use the key to find the parent | |
133 | * | |
134 | * on disk refs (inline or keyed) | |
135 | * ============================== | |
136 | * backref type | shared | indirect | shared | indirect | |
137 | * information | tree | tree | data | data | |
138 | * --------------------+--------+----------+--------+---------- | |
139 | * parent logical | y | - | y | - | |
140 | * key to resolve | - | - | - | y | |
141 | * tree block logical | y | y | y | y | |
142 | * root for resolving | - | y | y | y | |
143 | * | |
144 | * - column 1, 3: we've the parent -> done | |
145 | * - column 2: we take the first key from the block to find the parent | |
146 | * (see __add_missing_keys) | |
147 | * - column 4: we use the key to find the parent | |
148 | * | |
149 | * additional information that's available but not required to find the parent | |
150 | * block might help in merging entries to gain some speed. | |
151 | */ | |
152 | ||
8da6d581 | 153 | static int __add_prelim_ref(struct list_head *head, u64 root_id, |
d5c88b73 JS |
154 | struct btrfs_key *key, int level, |
155 | u64 parent, u64 wanted_disk_byte, int count) | |
8da6d581 JS |
156 | { |
157 | struct __prelim_ref *ref; | |
158 | ||
159 | /* in case we're adding delayed refs, we're holding the refs spinlock */ | |
160 | ref = kmalloc(sizeof(*ref), GFP_ATOMIC); | |
161 | if (!ref) | |
162 | return -ENOMEM; | |
163 | ||
164 | ref->root_id = root_id; | |
165 | if (key) | |
d5c88b73 | 166 | ref->key_for_search = *key; |
8da6d581 | 167 | else |
d5c88b73 | 168 | memset(&ref->key_for_search, 0, sizeof(ref->key_for_search)); |
8da6d581 | 169 | |
3301958b | 170 | ref->inode_list = NULL; |
8da6d581 JS |
171 | ref->level = level; |
172 | ref->count = count; | |
173 | ref->parent = parent; | |
174 | ref->wanted_disk_byte = wanted_disk_byte; | |
175 | list_add_tail(&ref->list, head); | |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
180 | static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, | |
976b1908 | 181 | struct ulist *parents, int level, |
69bca40d | 182 | struct btrfs_key *key_for_search, u64 time_seq, |
3d7806ec | 183 | u64 wanted_disk_byte, |
976b1908 | 184 | const u64 *extent_item_pos) |
8da6d581 | 185 | { |
69bca40d AB |
186 | int ret = 0; |
187 | int slot; | |
188 | struct extent_buffer *eb; | |
189 | struct btrfs_key key; | |
8da6d581 | 190 | struct btrfs_file_extent_item *fi; |
3301958b | 191 | struct extent_inode_elem *eie = NULL; |
8da6d581 JS |
192 | u64 disk_byte; |
193 | ||
69bca40d AB |
194 | if (level != 0) { |
195 | eb = path->nodes[level]; | |
196 | ret = ulist_add(parents, eb->start, 0, GFP_NOFS); | |
3301958b JS |
197 | if (ret < 0) |
198 | return ret; | |
8da6d581 | 199 | return 0; |
69bca40d | 200 | } |
8da6d581 JS |
201 | |
202 | /* | |
69bca40d AB |
203 | * We normally enter this function with the path already pointing to |
204 | * the first item to check. But sometimes, we may enter it with | |
205 | * slot==nritems. In that case, go to the next leaf before we continue. | |
8da6d581 | 206 | */ |
69bca40d | 207 | if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) |
3d7806ec | 208 | ret = btrfs_next_old_leaf(root, path, time_seq); |
8da6d581 | 209 | |
69bca40d | 210 | while (!ret) { |
8da6d581 | 211 | eb = path->nodes[0]; |
69bca40d AB |
212 | slot = path->slots[0]; |
213 | ||
214 | btrfs_item_key_to_cpu(eb, &key, slot); | |
215 | ||
216 | if (key.objectid != key_for_search->objectid || | |
217 | key.type != BTRFS_EXTENT_DATA_KEY) | |
218 | break; | |
219 | ||
220 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
221 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
222 | ||
223 | if (disk_byte == wanted_disk_byte) { | |
224 | eie = NULL; | |
225 | if (extent_item_pos) { | |
226 | ret = check_extent_in_eb(&key, eb, fi, | |
227 | *extent_item_pos, | |
228 | &eie); | |
229 | if (ret < 0) | |
230 | break; | |
231 | } | |
232 | if (!ret) { | |
233 | ret = ulist_add(parents, eb->start, | |
234 | (unsigned long)eie, GFP_NOFS); | |
235 | if (ret < 0) | |
236 | break; | |
237 | if (!extent_item_pos) { | |
238 | ret = btrfs_next_old_leaf(root, path, | |
239 | time_seq); | |
240 | continue; | |
241 | } | |
242 | } | |
8da6d581 | 243 | } |
69bca40d | 244 | ret = btrfs_next_old_item(root, path, time_seq); |
8da6d581 JS |
245 | } |
246 | ||
69bca40d AB |
247 | if (ret > 0) |
248 | ret = 0; | |
249 | return ret; | |
8da6d581 JS |
250 | } |
251 | ||
252 | /* | |
253 | * resolve an indirect backref in the form (root_id, key, level) | |
254 | * to a logical address | |
255 | */ | |
256 | static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, | |
7a3ae2f8 | 257 | int search_commit_root, |
8445f61c | 258 | u64 time_seq, |
8da6d581 | 259 | struct __prelim_ref *ref, |
976b1908 JS |
260 | struct ulist *parents, |
261 | const u64 *extent_item_pos) | |
8da6d581 JS |
262 | { |
263 | struct btrfs_path *path; | |
264 | struct btrfs_root *root; | |
265 | struct btrfs_key root_key; | |
8da6d581 JS |
266 | struct extent_buffer *eb; |
267 | int ret = 0; | |
268 | int root_level; | |
269 | int level = ref->level; | |
270 | ||
271 | path = btrfs_alloc_path(); | |
272 | if (!path) | |
273 | return -ENOMEM; | |
7a3ae2f8 | 274 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
275 | |
276 | root_key.objectid = ref->root_id; | |
277 | root_key.type = BTRFS_ROOT_ITEM_KEY; | |
278 | root_key.offset = (u64)-1; | |
279 | root = btrfs_read_fs_root_no_name(fs_info, &root_key); | |
280 | if (IS_ERR(root)) { | |
281 | ret = PTR_ERR(root); | |
282 | goto out; | |
283 | } | |
284 | ||
285 | rcu_read_lock(); | |
286 | root_level = btrfs_header_level(root->node); | |
287 | rcu_read_unlock(); | |
288 | ||
289 | if (root_level + 1 == level) | |
290 | goto out; | |
291 | ||
292 | path->lowest_level = level; | |
8445f61c | 293 | ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq); |
8da6d581 JS |
294 | pr_debug("search slot in root %llu (level %d, ref count %d) returned " |
295 | "%d for key (%llu %u %llu)\n", | |
296 | (unsigned long long)ref->root_id, level, ref->count, ret, | |
d5c88b73 JS |
297 | (unsigned long long)ref->key_for_search.objectid, |
298 | ref->key_for_search.type, | |
299 | (unsigned long long)ref->key_for_search.offset); | |
8da6d581 JS |
300 | if (ret < 0) |
301 | goto out; | |
302 | ||
303 | eb = path->nodes[level]; | |
304 | if (!eb) { | |
305 | WARN_ON(1); | |
306 | ret = 1; | |
307 | goto out; | |
308 | } | |
309 | ||
69bca40d AB |
310 | ret = add_all_parents(root, path, parents, level, &ref->key_for_search, |
311 | time_seq, ref->wanted_disk_byte, | |
312 | extent_item_pos); | |
8da6d581 JS |
313 | out: |
314 | btrfs_free_path(path); | |
315 | return ret; | |
316 | } | |
317 | ||
318 | /* | |
319 | * resolve all indirect backrefs from the list | |
320 | */ | |
321 | static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, | |
8445f61c | 322 | int search_commit_root, u64 time_seq, |
976b1908 JS |
323 | struct list_head *head, |
324 | const u64 *extent_item_pos) | |
8da6d581 JS |
325 | { |
326 | int err; | |
327 | int ret = 0; | |
328 | struct __prelim_ref *ref; | |
329 | struct __prelim_ref *ref_safe; | |
330 | struct __prelim_ref *new_ref; | |
331 | struct ulist *parents; | |
332 | struct ulist_node *node; | |
cd1b413c | 333 | struct ulist_iterator uiter; |
8da6d581 JS |
334 | |
335 | parents = ulist_alloc(GFP_NOFS); | |
336 | if (!parents) | |
337 | return -ENOMEM; | |
338 | ||
339 | /* | |
340 | * _safe allows us to insert directly after the current item without | |
341 | * iterating over the newly inserted items. | |
342 | * we're also allowed to re-assign ref during iteration. | |
343 | */ | |
344 | list_for_each_entry_safe(ref, ref_safe, head, list) { | |
345 | if (ref->parent) /* already direct */ | |
346 | continue; | |
347 | if (ref->count == 0) | |
348 | continue; | |
7a3ae2f8 | 349 | err = __resolve_indirect_ref(fs_info, search_commit_root, |
8445f61c JS |
350 | time_seq, ref, parents, |
351 | extent_item_pos); | |
8da6d581 JS |
352 | if (err) { |
353 | if (ret == 0) | |
354 | ret = err; | |
355 | continue; | |
356 | } | |
357 | ||
358 | /* we put the first parent into the ref at hand */ | |
cd1b413c JS |
359 | ULIST_ITER_INIT(&uiter); |
360 | node = ulist_next(parents, &uiter); | |
8da6d581 | 361 | ref->parent = node ? node->val : 0; |
3301958b JS |
362 | ref->inode_list = |
363 | node ? (struct extent_inode_elem *)node->aux : 0; | |
8da6d581 JS |
364 | |
365 | /* additional parents require new refs being added here */ | |
cd1b413c | 366 | while ((node = ulist_next(parents, &uiter))) { |
8da6d581 JS |
367 | new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); |
368 | if (!new_ref) { | |
369 | ret = -ENOMEM; | |
370 | break; | |
371 | } | |
372 | memcpy(new_ref, ref, sizeof(*ref)); | |
373 | new_ref->parent = node->val; | |
3301958b JS |
374 | new_ref->inode_list = |
375 | (struct extent_inode_elem *)node->aux; | |
8da6d581 JS |
376 | list_add(&new_ref->list, &ref->list); |
377 | } | |
378 | ulist_reinit(parents); | |
379 | } | |
380 | ||
381 | ulist_free(parents); | |
382 | return ret; | |
383 | } | |
384 | ||
d5c88b73 JS |
385 | static inline int ref_for_same_block(struct __prelim_ref *ref1, |
386 | struct __prelim_ref *ref2) | |
387 | { | |
388 | if (ref1->level != ref2->level) | |
389 | return 0; | |
390 | if (ref1->root_id != ref2->root_id) | |
391 | return 0; | |
392 | if (ref1->key_for_search.type != ref2->key_for_search.type) | |
393 | return 0; | |
394 | if (ref1->key_for_search.objectid != ref2->key_for_search.objectid) | |
395 | return 0; | |
396 | if (ref1->key_for_search.offset != ref2->key_for_search.offset) | |
397 | return 0; | |
398 | if (ref1->parent != ref2->parent) | |
399 | return 0; | |
400 | ||
401 | return 1; | |
402 | } | |
403 | ||
404 | /* | |
405 | * read tree blocks and add keys where required. | |
406 | */ | |
407 | static int __add_missing_keys(struct btrfs_fs_info *fs_info, | |
408 | struct list_head *head) | |
409 | { | |
410 | struct list_head *pos; | |
411 | struct extent_buffer *eb; | |
412 | ||
413 | list_for_each(pos, head) { | |
414 | struct __prelim_ref *ref; | |
415 | ref = list_entry(pos, struct __prelim_ref, list); | |
416 | ||
417 | if (ref->parent) | |
418 | continue; | |
419 | if (ref->key_for_search.type) | |
420 | continue; | |
421 | BUG_ON(!ref->wanted_disk_byte); | |
422 | eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte, | |
423 | fs_info->tree_root->leafsize, 0); | |
424 | BUG_ON(!eb); | |
425 | btrfs_tree_read_lock(eb); | |
426 | if (btrfs_header_level(eb) == 0) | |
427 | btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0); | |
428 | else | |
429 | btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0); | |
430 | btrfs_tree_read_unlock(eb); | |
431 | free_extent_buffer(eb); | |
432 | } | |
433 | return 0; | |
434 | } | |
435 | ||
8da6d581 JS |
436 | /* |
437 | * merge two lists of backrefs and adjust counts accordingly | |
438 | * | |
439 | * mode = 1: merge identical keys, if key is set | |
d5c88b73 JS |
440 | * FIXME: if we add more keys in __add_prelim_ref, we can merge more here. |
441 | * additionally, we could even add a key range for the blocks we | |
442 | * looked into to merge even more (-> replace unresolved refs by those | |
443 | * having a parent). | |
8da6d581 JS |
444 | * mode = 2: merge identical parents |
445 | */ | |
446 | static int __merge_refs(struct list_head *head, int mode) | |
447 | { | |
448 | struct list_head *pos1; | |
449 | ||
450 | list_for_each(pos1, head) { | |
451 | struct list_head *n2; | |
452 | struct list_head *pos2; | |
453 | struct __prelim_ref *ref1; | |
454 | ||
455 | ref1 = list_entry(pos1, struct __prelim_ref, list); | |
456 | ||
8da6d581 JS |
457 | for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; |
458 | pos2 = n2, n2 = pos2->next) { | |
459 | struct __prelim_ref *ref2; | |
d5c88b73 | 460 | struct __prelim_ref *xchg; |
8da6d581 JS |
461 | |
462 | ref2 = list_entry(pos2, struct __prelim_ref, list); | |
463 | ||
464 | if (mode == 1) { | |
d5c88b73 | 465 | if (!ref_for_same_block(ref1, ref2)) |
8da6d581 | 466 | continue; |
d5c88b73 JS |
467 | if (!ref1->parent && ref2->parent) { |
468 | xchg = ref1; | |
469 | ref1 = ref2; | |
470 | ref2 = xchg; | |
471 | } | |
8da6d581 JS |
472 | ref1->count += ref2->count; |
473 | } else { | |
474 | if (ref1->parent != ref2->parent) | |
475 | continue; | |
476 | ref1->count += ref2->count; | |
477 | } | |
478 | list_del(&ref2->list); | |
479 | kfree(ref2); | |
480 | } | |
481 | ||
482 | } | |
483 | return 0; | |
484 | } | |
485 | ||
486 | /* | |
487 | * add all currently queued delayed refs from this head whose seq nr is | |
488 | * smaller or equal that seq to the list | |
489 | */ | |
490 | static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, | |
8da6d581 JS |
491 | struct list_head *prefs) |
492 | { | |
493 | struct btrfs_delayed_extent_op *extent_op = head->extent_op; | |
494 | struct rb_node *n = &head->node.rb_node; | |
d5c88b73 JS |
495 | struct btrfs_key key; |
496 | struct btrfs_key op_key = {0}; | |
8da6d581 | 497 | int sgn; |
b1375d64 | 498 | int ret = 0; |
8da6d581 JS |
499 | |
500 | if (extent_op && extent_op->update_key) | |
d5c88b73 | 501 | btrfs_disk_key_to_cpu(&op_key, &extent_op->key); |
8da6d581 JS |
502 | |
503 | while ((n = rb_prev(n))) { | |
504 | struct btrfs_delayed_ref_node *node; | |
505 | node = rb_entry(n, struct btrfs_delayed_ref_node, | |
506 | rb_node); | |
507 | if (node->bytenr != head->node.bytenr) | |
508 | break; | |
509 | WARN_ON(node->is_head); | |
510 | ||
511 | if (node->seq > seq) | |
512 | continue; | |
513 | ||
514 | switch (node->action) { | |
515 | case BTRFS_ADD_DELAYED_EXTENT: | |
516 | case BTRFS_UPDATE_DELAYED_HEAD: | |
517 | WARN_ON(1); | |
518 | continue; | |
519 | case BTRFS_ADD_DELAYED_REF: | |
520 | sgn = 1; | |
521 | break; | |
522 | case BTRFS_DROP_DELAYED_REF: | |
523 | sgn = -1; | |
524 | break; | |
525 | default: | |
526 | BUG_ON(1); | |
527 | } | |
528 | switch (node->type) { | |
529 | case BTRFS_TREE_BLOCK_REF_KEY: { | |
530 | struct btrfs_delayed_tree_ref *ref; | |
531 | ||
532 | ref = btrfs_delayed_node_to_tree_ref(node); | |
d5c88b73 | 533 | ret = __add_prelim_ref(prefs, ref->root, &op_key, |
8da6d581 JS |
534 | ref->level + 1, 0, node->bytenr, |
535 | node->ref_mod * sgn); | |
536 | break; | |
537 | } | |
538 | case BTRFS_SHARED_BLOCK_REF_KEY: { | |
539 | struct btrfs_delayed_tree_ref *ref; | |
540 | ||
541 | ref = btrfs_delayed_node_to_tree_ref(node); | |
d5c88b73 | 542 | ret = __add_prelim_ref(prefs, ref->root, NULL, |
8da6d581 JS |
543 | ref->level + 1, ref->parent, |
544 | node->bytenr, | |
545 | node->ref_mod * sgn); | |
546 | break; | |
547 | } | |
548 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
549 | struct btrfs_delayed_data_ref *ref; | |
8da6d581 JS |
550 | ref = btrfs_delayed_node_to_data_ref(node); |
551 | ||
552 | key.objectid = ref->objectid; | |
553 | key.type = BTRFS_EXTENT_DATA_KEY; | |
554 | key.offset = ref->offset; | |
555 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, | |
556 | node->bytenr, | |
557 | node->ref_mod * sgn); | |
558 | break; | |
559 | } | |
560 | case BTRFS_SHARED_DATA_REF_KEY: { | |
561 | struct btrfs_delayed_data_ref *ref; | |
8da6d581 JS |
562 | |
563 | ref = btrfs_delayed_node_to_data_ref(node); | |
564 | ||
565 | key.objectid = ref->objectid; | |
566 | key.type = BTRFS_EXTENT_DATA_KEY; | |
567 | key.offset = ref->offset; | |
568 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, | |
569 | ref->parent, node->bytenr, | |
570 | node->ref_mod * sgn); | |
571 | break; | |
572 | } | |
573 | default: | |
574 | WARN_ON(1); | |
575 | } | |
576 | BUG_ON(ret); | |
577 | } | |
578 | ||
579 | return 0; | |
580 | } | |
581 | ||
582 | /* | |
583 | * add all inline backrefs for bytenr to the list | |
584 | */ | |
585 | static int __add_inline_refs(struct btrfs_fs_info *fs_info, | |
586 | struct btrfs_path *path, u64 bytenr, | |
d5c88b73 | 587 | int *info_level, struct list_head *prefs) |
8da6d581 | 588 | { |
b1375d64 | 589 | int ret = 0; |
8da6d581 JS |
590 | int slot; |
591 | struct extent_buffer *leaf; | |
592 | struct btrfs_key key; | |
593 | unsigned long ptr; | |
594 | unsigned long end; | |
595 | struct btrfs_extent_item *ei; | |
596 | u64 flags; | |
597 | u64 item_size; | |
598 | ||
599 | /* | |
600 | * enumerate all inline refs | |
601 | */ | |
602 | leaf = path->nodes[0]; | |
dadcaf78 | 603 | slot = path->slots[0]; |
8da6d581 JS |
604 | |
605 | item_size = btrfs_item_size_nr(leaf, slot); | |
606 | BUG_ON(item_size < sizeof(*ei)); | |
607 | ||
608 | ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); | |
609 | flags = btrfs_extent_flags(leaf, ei); | |
610 | ||
611 | ptr = (unsigned long)(ei + 1); | |
612 | end = (unsigned long)ei + item_size; | |
613 | ||
614 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
615 | struct btrfs_tree_block_info *info; | |
8da6d581 JS |
616 | |
617 | info = (struct btrfs_tree_block_info *)ptr; | |
618 | *info_level = btrfs_tree_block_level(leaf, info); | |
8da6d581 JS |
619 | ptr += sizeof(struct btrfs_tree_block_info); |
620 | BUG_ON(ptr > end); | |
621 | } else { | |
622 | BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); | |
623 | } | |
624 | ||
625 | while (ptr < end) { | |
626 | struct btrfs_extent_inline_ref *iref; | |
627 | u64 offset; | |
628 | int type; | |
629 | ||
630 | iref = (struct btrfs_extent_inline_ref *)ptr; | |
631 | type = btrfs_extent_inline_ref_type(leaf, iref); | |
632 | offset = btrfs_extent_inline_ref_offset(leaf, iref); | |
633 | ||
634 | switch (type) { | |
635 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
d5c88b73 | 636 | ret = __add_prelim_ref(prefs, 0, NULL, |
8da6d581 JS |
637 | *info_level + 1, offset, |
638 | bytenr, 1); | |
639 | break; | |
640 | case BTRFS_SHARED_DATA_REF_KEY: { | |
641 | struct btrfs_shared_data_ref *sdref; | |
642 | int count; | |
643 | ||
644 | sdref = (struct btrfs_shared_data_ref *)(iref + 1); | |
645 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
646 | ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, | |
647 | bytenr, count); | |
648 | break; | |
649 | } | |
650 | case BTRFS_TREE_BLOCK_REF_KEY: | |
d5c88b73 JS |
651 | ret = __add_prelim_ref(prefs, offset, NULL, |
652 | *info_level + 1, 0, | |
653 | bytenr, 1); | |
8da6d581 JS |
654 | break; |
655 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
656 | struct btrfs_extent_data_ref *dref; | |
657 | int count; | |
658 | u64 root; | |
659 | ||
660 | dref = (struct btrfs_extent_data_ref *)(&iref->offset); | |
661 | count = btrfs_extent_data_ref_count(leaf, dref); | |
662 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
663 | dref); | |
664 | key.type = BTRFS_EXTENT_DATA_KEY; | |
665 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
666 | root = btrfs_extent_data_ref_root(leaf, dref); | |
d5c88b73 JS |
667 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, |
668 | bytenr, count); | |
8da6d581 JS |
669 | break; |
670 | } | |
671 | default: | |
672 | WARN_ON(1); | |
673 | } | |
674 | BUG_ON(ret); | |
675 | ptr += btrfs_extent_inline_ref_size(type); | |
676 | } | |
677 | ||
678 | return 0; | |
679 | } | |
680 | ||
681 | /* | |
682 | * add all non-inline backrefs for bytenr to the list | |
683 | */ | |
684 | static int __add_keyed_refs(struct btrfs_fs_info *fs_info, | |
685 | struct btrfs_path *path, u64 bytenr, | |
d5c88b73 | 686 | int info_level, struct list_head *prefs) |
8da6d581 JS |
687 | { |
688 | struct btrfs_root *extent_root = fs_info->extent_root; | |
689 | int ret; | |
690 | int slot; | |
691 | struct extent_buffer *leaf; | |
692 | struct btrfs_key key; | |
693 | ||
694 | while (1) { | |
695 | ret = btrfs_next_item(extent_root, path); | |
696 | if (ret < 0) | |
697 | break; | |
698 | if (ret) { | |
699 | ret = 0; | |
700 | break; | |
701 | } | |
702 | ||
703 | slot = path->slots[0]; | |
704 | leaf = path->nodes[0]; | |
705 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
706 | ||
707 | if (key.objectid != bytenr) | |
708 | break; | |
709 | if (key.type < BTRFS_TREE_BLOCK_REF_KEY) | |
710 | continue; | |
711 | if (key.type > BTRFS_SHARED_DATA_REF_KEY) | |
712 | break; | |
713 | ||
714 | switch (key.type) { | |
715 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
d5c88b73 | 716 | ret = __add_prelim_ref(prefs, 0, NULL, |
8da6d581 JS |
717 | info_level + 1, key.offset, |
718 | bytenr, 1); | |
719 | break; | |
720 | case BTRFS_SHARED_DATA_REF_KEY: { | |
721 | struct btrfs_shared_data_ref *sdref; | |
722 | int count; | |
723 | ||
724 | sdref = btrfs_item_ptr(leaf, slot, | |
725 | struct btrfs_shared_data_ref); | |
726 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
727 | ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, | |
728 | bytenr, count); | |
729 | break; | |
730 | } | |
731 | case BTRFS_TREE_BLOCK_REF_KEY: | |
d5c88b73 JS |
732 | ret = __add_prelim_ref(prefs, key.offset, NULL, |
733 | info_level + 1, 0, | |
734 | bytenr, 1); | |
8da6d581 JS |
735 | break; |
736 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
737 | struct btrfs_extent_data_ref *dref; | |
738 | int count; | |
739 | u64 root; | |
740 | ||
741 | dref = btrfs_item_ptr(leaf, slot, | |
742 | struct btrfs_extent_data_ref); | |
743 | count = btrfs_extent_data_ref_count(leaf, dref); | |
744 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
745 | dref); | |
746 | key.type = BTRFS_EXTENT_DATA_KEY; | |
747 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
748 | root = btrfs_extent_data_ref_root(leaf, dref); | |
749 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, | |
d5c88b73 | 750 | bytenr, count); |
8da6d581 JS |
751 | break; |
752 | } | |
753 | default: | |
754 | WARN_ON(1); | |
755 | } | |
756 | BUG_ON(ret); | |
757 | } | |
758 | ||
759 | return ret; | |
760 | } | |
761 | ||
762 | /* | |
763 | * this adds all existing backrefs (inline backrefs, backrefs and delayed | |
764 | * refs) for the given bytenr to the refs list, merges duplicates and resolves | |
765 | * indirect refs to their parent bytenr. | |
766 | * When roots are found, they're added to the roots list | |
767 | * | |
768 | * FIXME some caching might speed things up | |
769 | */ | |
770 | static int find_parent_nodes(struct btrfs_trans_handle *trans, | |
771 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
8445f61c JS |
772 | u64 delayed_ref_seq, u64 time_seq, |
773 | struct ulist *refs, struct ulist *roots, | |
976b1908 | 774 | const u64 *extent_item_pos) |
8da6d581 JS |
775 | { |
776 | struct btrfs_key key; | |
777 | struct btrfs_path *path; | |
8da6d581 | 778 | struct btrfs_delayed_ref_root *delayed_refs = NULL; |
d3b01064 | 779 | struct btrfs_delayed_ref_head *head; |
8da6d581 JS |
780 | int info_level = 0; |
781 | int ret; | |
7a3ae2f8 | 782 | int search_commit_root = (trans == BTRFS_BACKREF_SEARCH_COMMIT_ROOT); |
8da6d581 JS |
783 | struct list_head prefs_delayed; |
784 | struct list_head prefs; | |
785 | struct __prelim_ref *ref; | |
786 | ||
787 | INIT_LIST_HEAD(&prefs); | |
788 | INIT_LIST_HEAD(&prefs_delayed); | |
789 | ||
790 | key.objectid = bytenr; | |
791 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
792 | key.offset = (u64)-1; | |
793 | ||
794 | path = btrfs_alloc_path(); | |
795 | if (!path) | |
796 | return -ENOMEM; | |
7a3ae2f8 | 797 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
798 | |
799 | /* | |
800 | * grab both a lock on the path and a lock on the delayed ref head. | |
801 | * We need both to get a consistent picture of how the refs look | |
802 | * at a specified point in time | |
803 | */ | |
804 | again: | |
d3b01064 LZ |
805 | head = NULL; |
806 | ||
8da6d581 JS |
807 | ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); |
808 | if (ret < 0) | |
809 | goto out; | |
810 | BUG_ON(ret == 0); | |
811 | ||
7a3ae2f8 JS |
812 | if (trans != BTRFS_BACKREF_SEARCH_COMMIT_ROOT) { |
813 | /* | |
814 | * look if there are updates for this ref queued and lock the | |
815 | * head | |
816 | */ | |
817 | delayed_refs = &trans->transaction->delayed_refs; | |
818 | spin_lock(&delayed_refs->lock); | |
819 | head = btrfs_find_delayed_ref_head(trans, bytenr); | |
820 | if (head) { | |
821 | if (!mutex_trylock(&head->mutex)) { | |
822 | atomic_inc(&head->node.refs); | |
823 | spin_unlock(&delayed_refs->lock); | |
824 | ||
825 | btrfs_release_path(path); | |
826 | ||
827 | /* | |
828 | * Mutex was contended, block until it's | |
829 | * released and try again | |
830 | */ | |
831 | mutex_lock(&head->mutex); | |
832 | mutex_unlock(&head->mutex); | |
833 | btrfs_put_delayed_ref(&head->node); | |
834 | goto again; | |
835 | } | |
8445f61c JS |
836 | ret = __add_delayed_refs(head, delayed_ref_seq, |
837 | &prefs_delayed); | |
7a3ae2f8 JS |
838 | if (ret) { |
839 | spin_unlock(&delayed_refs->lock); | |
840 | goto out; | |
841 | } | |
d3b01064 | 842 | } |
7a3ae2f8 | 843 | spin_unlock(&delayed_refs->lock); |
8da6d581 | 844 | } |
8da6d581 JS |
845 | |
846 | if (path->slots[0]) { | |
847 | struct extent_buffer *leaf; | |
848 | int slot; | |
849 | ||
dadcaf78 | 850 | path->slots[0]--; |
8da6d581 | 851 | leaf = path->nodes[0]; |
dadcaf78 | 852 | slot = path->slots[0]; |
8da6d581 JS |
853 | btrfs_item_key_to_cpu(leaf, &key, slot); |
854 | if (key.objectid == bytenr && | |
855 | key.type == BTRFS_EXTENT_ITEM_KEY) { | |
856 | ret = __add_inline_refs(fs_info, path, bytenr, | |
d5c88b73 | 857 | &info_level, &prefs); |
8da6d581 JS |
858 | if (ret) |
859 | goto out; | |
d5c88b73 | 860 | ret = __add_keyed_refs(fs_info, path, bytenr, |
8da6d581 JS |
861 | info_level, &prefs); |
862 | if (ret) | |
863 | goto out; | |
864 | } | |
865 | } | |
866 | btrfs_release_path(path); | |
867 | ||
8da6d581 JS |
868 | list_splice_init(&prefs_delayed, &prefs); |
869 | ||
d5c88b73 JS |
870 | ret = __add_missing_keys(fs_info, &prefs); |
871 | if (ret) | |
872 | goto out; | |
873 | ||
8da6d581 JS |
874 | ret = __merge_refs(&prefs, 1); |
875 | if (ret) | |
876 | goto out; | |
877 | ||
8445f61c JS |
878 | ret = __resolve_indirect_refs(fs_info, search_commit_root, time_seq, |
879 | &prefs, extent_item_pos); | |
8da6d581 JS |
880 | if (ret) |
881 | goto out; | |
882 | ||
883 | ret = __merge_refs(&prefs, 2); | |
884 | if (ret) | |
885 | goto out; | |
886 | ||
887 | while (!list_empty(&prefs)) { | |
888 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
889 | list_del(&ref->list); | |
890 | if (ref->count < 0) | |
891 | WARN_ON(1); | |
892 | if (ref->count && ref->root_id && ref->parent == 0) { | |
893 | /* no parent == root of tree */ | |
894 | ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); | |
895 | BUG_ON(ret < 0); | |
896 | } | |
897 | if (ref->count && ref->parent) { | |
976b1908 | 898 | struct extent_inode_elem *eie = NULL; |
3301958b | 899 | if (extent_item_pos && !ref->inode_list) { |
976b1908 JS |
900 | u32 bsz; |
901 | struct extent_buffer *eb; | |
902 | bsz = btrfs_level_size(fs_info->extent_root, | |
903 | info_level); | |
904 | eb = read_tree_block(fs_info->extent_root, | |
905 | ref->parent, bsz, 0); | |
906 | BUG_ON(!eb); | |
907 | ret = find_extent_in_eb(eb, bytenr, | |
908 | *extent_item_pos, &eie); | |
3301958b | 909 | ref->inode_list = eie; |
976b1908 JS |
910 | free_extent_buffer(eb); |
911 | } | |
3301958b JS |
912 | ret = ulist_add_merge(refs, ref->parent, |
913 | (unsigned long)ref->inode_list, | |
914 | (unsigned long *)&eie, GFP_NOFS); | |
915 | if (!ret && extent_item_pos) { | |
916 | /* | |
917 | * we've recorded that parent, so we must extend | |
918 | * its inode list here | |
919 | */ | |
920 | BUG_ON(!eie); | |
921 | while (eie->next) | |
922 | eie = eie->next; | |
923 | eie->next = ref->inode_list; | |
924 | } | |
8da6d581 JS |
925 | BUG_ON(ret < 0); |
926 | } | |
927 | kfree(ref); | |
928 | } | |
929 | ||
930 | out: | |
931 | if (head) | |
932 | mutex_unlock(&head->mutex); | |
933 | btrfs_free_path(path); | |
934 | while (!list_empty(&prefs)) { | |
935 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
936 | list_del(&ref->list); | |
937 | kfree(ref); | |
938 | } | |
939 | while (!list_empty(&prefs_delayed)) { | |
940 | ref = list_first_entry(&prefs_delayed, struct __prelim_ref, | |
941 | list); | |
942 | list_del(&ref->list); | |
943 | kfree(ref); | |
944 | } | |
945 | ||
946 | return ret; | |
947 | } | |
948 | ||
976b1908 JS |
949 | static void free_leaf_list(struct ulist *blocks) |
950 | { | |
951 | struct ulist_node *node = NULL; | |
952 | struct extent_inode_elem *eie; | |
953 | struct extent_inode_elem *eie_next; | |
954 | struct ulist_iterator uiter; | |
955 | ||
956 | ULIST_ITER_INIT(&uiter); | |
957 | while ((node = ulist_next(blocks, &uiter))) { | |
958 | if (!node->aux) | |
959 | continue; | |
960 | eie = (struct extent_inode_elem *)node->aux; | |
961 | for (; eie; eie = eie_next) { | |
962 | eie_next = eie->next; | |
963 | kfree(eie); | |
964 | } | |
965 | node->aux = 0; | |
966 | } | |
967 | ||
968 | ulist_free(blocks); | |
969 | } | |
970 | ||
8da6d581 JS |
971 | /* |
972 | * Finds all leafs with a reference to the specified combination of bytenr and | |
973 | * offset. key_list_head will point to a list of corresponding keys (caller must | |
974 | * free each list element). The leafs will be stored in the leafs ulist, which | |
975 | * must be freed with ulist_free. | |
976 | * | |
977 | * returns 0 on success, <0 on error | |
978 | */ | |
979 | static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, | |
980 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
8445f61c JS |
981 | u64 delayed_ref_seq, u64 time_seq, |
982 | struct ulist **leafs, | |
976b1908 | 983 | const u64 *extent_item_pos) |
8da6d581 JS |
984 | { |
985 | struct ulist *tmp; | |
986 | int ret; | |
987 | ||
988 | tmp = ulist_alloc(GFP_NOFS); | |
989 | if (!tmp) | |
990 | return -ENOMEM; | |
991 | *leafs = ulist_alloc(GFP_NOFS); | |
992 | if (!*leafs) { | |
993 | ulist_free(tmp); | |
994 | return -ENOMEM; | |
995 | } | |
996 | ||
8445f61c JS |
997 | ret = find_parent_nodes(trans, fs_info, bytenr, delayed_ref_seq, |
998 | time_seq, *leafs, tmp, extent_item_pos); | |
8da6d581 JS |
999 | ulist_free(tmp); |
1000 | ||
1001 | if (ret < 0 && ret != -ENOENT) { | |
976b1908 | 1002 | free_leaf_list(*leafs); |
8da6d581 JS |
1003 | return ret; |
1004 | } | |
1005 | ||
1006 | return 0; | |
1007 | } | |
1008 | ||
1009 | /* | |
1010 | * walk all backrefs for a given extent to find all roots that reference this | |
1011 | * extent. Walking a backref means finding all extents that reference this | |
1012 | * extent and in turn walk the backrefs of those, too. Naturally this is a | |
1013 | * recursive process, but here it is implemented in an iterative fashion: We | |
1014 | * find all referencing extents for the extent in question and put them on a | |
1015 | * list. In turn, we find all referencing extents for those, further appending | |
1016 | * to the list. The way we iterate the list allows adding more elements after | |
1017 | * the current while iterating. The process stops when we reach the end of the | |
1018 | * list. Found roots are added to the roots list. | |
1019 | * | |
1020 | * returns 0 on success, < 0 on error. | |
1021 | */ | |
1022 | int btrfs_find_all_roots(struct btrfs_trans_handle *trans, | |
1023 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
8445f61c JS |
1024 | u64 delayed_ref_seq, u64 time_seq, |
1025 | struct ulist **roots) | |
8da6d581 JS |
1026 | { |
1027 | struct ulist *tmp; | |
1028 | struct ulist_node *node = NULL; | |
cd1b413c | 1029 | struct ulist_iterator uiter; |
8da6d581 JS |
1030 | int ret; |
1031 | ||
1032 | tmp = ulist_alloc(GFP_NOFS); | |
1033 | if (!tmp) | |
1034 | return -ENOMEM; | |
1035 | *roots = ulist_alloc(GFP_NOFS); | |
1036 | if (!*roots) { | |
1037 | ulist_free(tmp); | |
1038 | return -ENOMEM; | |
1039 | } | |
1040 | ||
cd1b413c | 1041 | ULIST_ITER_INIT(&uiter); |
8da6d581 | 1042 | while (1) { |
8445f61c JS |
1043 | ret = find_parent_nodes(trans, fs_info, bytenr, delayed_ref_seq, |
1044 | time_seq, tmp, *roots, NULL); | |
8da6d581 JS |
1045 | if (ret < 0 && ret != -ENOENT) { |
1046 | ulist_free(tmp); | |
1047 | ulist_free(*roots); | |
1048 | return ret; | |
1049 | } | |
cd1b413c | 1050 | node = ulist_next(tmp, &uiter); |
8da6d581 JS |
1051 | if (!node) |
1052 | break; | |
1053 | bytenr = node->val; | |
1054 | } | |
1055 | ||
1056 | ulist_free(tmp); | |
1057 | return 0; | |
1058 | } | |
1059 | ||
1060 | ||
a542ad1b JS |
1061 | static int __inode_info(u64 inum, u64 ioff, u8 key_type, |
1062 | struct btrfs_root *fs_root, struct btrfs_path *path, | |
1063 | struct btrfs_key *found_key) | |
1064 | { | |
1065 | int ret; | |
1066 | struct btrfs_key key; | |
1067 | struct extent_buffer *eb; | |
1068 | ||
1069 | key.type = key_type; | |
1070 | key.objectid = inum; | |
1071 | key.offset = ioff; | |
1072 | ||
1073 | ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); | |
1074 | if (ret < 0) | |
1075 | return ret; | |
1076 | ||
1077 | eb = path->nodes[0]; | |
1078 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { | |
1079 | ret = btrfs_next_leaf(fs_root, path); | |
1080 | if (ret) | |
1081 | return ret; | |
1082 | eb = path->nodes[0]; | |
1083 | } | |
1084 | ||
1085 | btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); | |
1086 | if (found_key->type != key.type || found_key->objectid != key.objectid) | |
1087 | return 1; | |
1088 | ||
1089 | return 0; | |
1090 | } | |
1091 | ||
1092 | /* | |
1093 | * this makes the path point to (inum INODE_ITEM ioff) | |
1094 | */ | |
1095 | int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
1096 | struct btrfs_path *path) | |
1097 | { | |
1098 | struct btrfs_key key; | |
1099 | return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, | |
1100 | &key); | |
1101 | } | |
1102 | ||
1103 | static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
1104 | struct btrfs_path *path, | |
1105 | struct btrfs_key *found_key) | |
1106 | { | |
1107 | return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, | |
1108 | found_key); | |
1109 | } | |
1110 | ||
1111 | /* | |
1112 | * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements | |
1113 | * of the path are separated by '/' and the path is guaranteed to be | |
1114 | * 0-terminated. the path is only given within the current file system. | |
1115 | * Therefore, it never starts with a '/'. the caller is responsible to provide | |
1116 | * "size" bytes in "dest". the dest buffer will be filled backwards. finally, | |
1117 | * the start point of the resulting string is returned. this pointer is within | |
1118 | * dest, normally. | |
1119 | * in case the path buffer would overflow, the pointer is decremented further | |
1120 | * as if output was written to the buffer, though no more output is actually | |
1121 | * generated. that way, the caller can determine how much space would be | |
1122 | * required for the path to fit into the buffer. in that case, the returned | |
1123 | * value will be smaller than dest. callers must check this! | |
1124 | */ | |
1125 | static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, | |
1126 | struct btrfs_inode_ref *iref, | |
1127 | struct extent_buffer *eb_in, u64 parent, | |
1128 | char *dest, u32 size) | |
1129 | { | |
1130 | u32 len; | |
1131 | int slot; | |
1132 | u64 next_inum; | |
1133 | int ret; | |
1134 | s64 bytes_left = size - 1; | |
1135 | struct extent_buffer *eb = eb_in; | |
1136 | struct btrfs_key found_key; | |
b916a59a | 1137 | int leave_spinning = path->leave_spinning; |
a542ad1b JS |
1138 | |
1139 | if (bytes_left >= 0) | |
1140 | dest[bytes_left] = '\0'; | |
1141 | ||
b916a59a | 1142 | path->leave_spinning = 1; |
a542ad1b JS |
1143 | while (1) { |
1144 | len = btrfs_inode_ref_name_len(eb, iref); | |
1145 | bytes_left -= len; | |
1146 | if (bytes_left >= 0) | |
1147 | read_extent_buffer(eb, dest + bytes_left, | |
1148 | (unsigned long)(iref + 1), len); | |
b916a59a JS |
1149 | if (eb != eb_in) { |
1150 | btrfs_tree_read_unlock_blocking(eb); | |
a542ad1b | 1151 | free_extent_buffer(eb); |
b916a59a | 1152 | } |
a542ad1b | 1153 | ret = inode_ref_info(parent, 0, fs_root, path, &found_key); |
8f24b496 JS |
1154 | if (ret > 0) |
1155 | ret = -ENOENT; | |
a542ad1b JS |
1156 | if (ret) |
1157 | break; | |
1158 | next_inum = found_key.offset; | |
1159 | ||
1160 | /* regular exit ahead */ | |
1161 | if (parent == next_inum) | |
1162 | break; | |
1163 | ||
1164 | slot = path->slots[0]; | |
1165 | eb = path->nodes[0]; | |
1166 | /* make sure we can use eb after releasing the path */ | |
b916a59a | 1167 | if (eb != eb_in) { |
a542ad1b | 1168 | atomic_inc(&eb->refs); |
b916a59a JS |
1169 | btrfs_tree_read_lock(eb); |
1170 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
1171 | } | |
a542ad1b JS |
1172 | btrfs_release_path(path); |
1173 | ||
1174 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
1175 | parent = next_inum; | |
1176 | --bytes_left; | |
1177 | if (bytes_left >= 0) | |
1178 | dest[bytes_left] = '/'; | |
1179 | } | |
1180 | ||
1181 | btrfs_release_path(path); | |
b916a59a | 1182 | path->leave_spinning = leave_spinning; |
a542ad1b JS |
1183 | |
1184 | if (ret) | |
1185 | return ERR_PTR(ret); | |
1186 | ||
1187 | return dest + bytes_left; | |
1188 | } | |
1189 | ||
1190 | /* | |
1191 | * this makes the path point to (logical EXTENT_ITEM *) | |
1192 | * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for | |
1193 | * tree blocks and <0 on error. | |
1194 | */ | |
1195 | int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, | |
1196 | struct btrfs_path *path, struct btrfs_key *found_key) | |
1197 | { | |
1198 | int ret; | |
1199 | u64 flags; | |
1200 | u32 item_size; | |
1201 | struct extent_buffer *eb; | |
1202 | struct btrfs_extent_item *ei; | |
1203 | struct btrfs_key key; | |
1204 | ||
1205 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
1206 | key.objectid = logical; | |
1207 | key.offset = (u64)-1; | |
1208 | ||
1209 | ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); | |
1210 | if (ret < 0) | |
1211 | return ret; | |
1212 | ret = btrfs_previous_item(fs_info->extent_root, path, | |
1213 | 0, BTRFS_EXTENT_ITEM_KEY); | |
1214 | if (ret < 0) | |
1215 | return ret; | |
1216 | ||
1217 | btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); | |
1218 | if (found_key->type != BTRFS_EXTENT_ITEM_KEY || | |
1219 | found_key->objectid > logical || | |
4692cf58 JS |
1220 | found_key->objectid + found_key->offset <= logical) { |
1221 | pr_debug("logical %llu is not within any extent\n", | |
1222 | (unsigned long long)logical); | |
a542ad1b | 1223 | return -ENOENT; |
4692cf58 | 1224 | } |
a542ad1b JS |
1225 | |
1226 | eb = path->nodes[0]; | |
1227 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
1228 | BUG_ON(item_size < sizeof(*ei)); | |
1229 | ||
1230 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
1231 | flags = btrfs_extent_flags(eb, ei); | |
1232 | ||
4692cf58 JS |
1233 | pr_debug("logical %llu is at position %llu within the extent (%llu " |
1234 | "EXTENT_ITEM %llu) flags %#llx size %u\n", | |
1235 | (unsigned long long)logical, | |
1236 | (unsigned long long)(logical - found_key->objectid), | |
1237 | (unsigned long long)found_key->objectid, | |
1238 | (unsigned long long)found_key->offset, | |
1239 | (unsigned long long)flags, item_size); | |
a542ad1b JS |
1240 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
1241 | return BTRFS_EXTENT_FLAG_TREE_BLOCK; | |
1242 | if (flags & BTRFS_EXTENT_FLAG_DATA) | |
1243 | return BTRFS_EXTENT_FLAG_DATA; | |
1244 | ||
1245 | return -EIO; | |
1246 | } | |
1247 | ||
1248 | /* | |
1249 | * helper function to iterate extent inline refs. ptr must point to a 0 value | |
1250 | * for the first call and may be modified. it is used to track state. | |
1251 | * if more refs exist, 0 is returned and the next call to | |
1252 | * __get_extent_inline_ref must pass the modified ptr parameter to get the | |
1253 | * next ref. after the last ref was processed, 1 is returned. | |
1254 | * returns <0 on error | |
1255 | */ | |
1256 | static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, | |
1257 | struct btrfs_extent_item *ei, u32 item_size, | |
1258 | struct btrfs_extent_inline_ref **out_eiref, | |
1259 | int *out_type) | |
1260 | { | |
1261 | unsigned long end; | |
1262 | u64 flags; | |
1263 | struct btrfs_tree_block_info *info; | |
1264 | ||
1265 | if (!*ptr) { | |
1266 | /* first call */ | |
1267 | flags = btrfs_extent_flags(eb, ei); | |
1268 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
1269 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1270 | *out_eiref = | |
1271 | (struct btrfs_extent_inline_ref *)(info + 1); | |
1272 | } else { | |
1273 | *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); | |
1274 | } | |
1275 | *ptr = (unsigned long)*out_eiref; | |
1276 | if ((void *)*ptr >= (void *)ei + item_size) | |
1277 | return -ENOENT; | |
1278 | } | |
1279 | ||
1280 | end = (unsigned long)ei + item_size; | |
1281 | *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; | |
1282 | *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); | |
1283 | ||
1284 | *ptr += btrfs_extent_inline_ref_size(*out_type); | |
1285 | WARN_ON(*ptr > end); | |
1286 | if (*ptr == end) | |
1287 | return 1; /* last */ | |
1288 | ||
1289 | return 0; | |
1290 | } | |
1291 | ||
1292 | /* | |
1293 | * reads the tree block backref for an extent. tree level and root are returned | |
1294 | * through out_level and out_root. ptr must point to a 0 value for the first | |
1295 | * call and may be modified (see __get_extent_inline_ref comment). | |
1296 | * returns 0 if data was provided, 1 if there was no more data to provide or | |
1297 | * <0 on error. | |
1298 | */ | |
1299 | int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, | |
1300 | struct btrfs_extent_item *ei, u32 item_size, | |
1301 | u64 *out_root, u8 *out_level) | |
1302 | { | |
1303 | int ret; | |
1304 | int type; | |
1305 | struct btrfs_tree_block_info *info; | |
1306 | struct btrfs_extent_inline_ref *eiref; | |
1307 | ||
1308 | if (*ptr == (unsigned long)-1) | |
1309 | return 1; | |
1310 | ||
1311 | while (1) { | |
1312 | ret = __get_extent_inline_ref(ptr, eb, ei, item_size, | |
1313 | &eiref, &type); | |
1314 | if (ret < 0) | |
1315 | return ret; | |
1316 | ||
1317 | if (type == BTRFS_TREE_BLOCK_REF_KEY || | |
1318 | type == BTRFS_SHARED_BLOCK_REF_KEY) | |
1319 | break; | |
1320 | ||
1321 | if (ret == 1) | |
1322 | return 1; | |
1323 | } | |
1324 | ||
1325 | /* we can treat both ref types equally here */ | |
1326 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1327 | *out_root = btrfs_extent_inline_ref_offset(eb, eiref); | |
1328 | *out_level = btrfs_tree_block_level(eb, info); | |
1329 | ||
1330 | if (ret == 1) | |
1331 | *ptr = (unsigned long)-1; | |
1332 | ||
1333 | return 0; | |
1334 | } | |
1335 | ||
976b1908 JS |
1336 | static int iterate_leaf_refs(struct extent_inode_elem *inode_list, |
1337 | u64 root, u64 extent_item_objectid, | |
4692cf58 | 1338 | iterate_extent_inodes_t *iterate, void *ctx) |
a542ad1b | 1339 | { |
976b1908 | 1340 | struct extent_inode_elem *eie; |
4692cf58 | 1341 | int ret = 0; |
4692cf58 | 1342 | |
976b1908 | 1343 | for (eie = inode_list; eie; eie = eie->next) { |
4692cf58 | 1344 | pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " |
976b1908 JS |
1345 | "root %llu\n", extent_item_objectid, |
1346 | eie->inum, eie->offset, root); | |
1347 | ret = iterate(eie->inum, eie->offset, root, ctx); | |
4692cf58 | 1348 | if (ret) { |
976b1908 JS |
1349 | pr_debug("stopping iteration for %llu due to ret=%d\n", |
1350 | extent_item_objectid, ret); | |
4692cf58 JS |
1351 | break; |
1352 | } | |
a542ad1b JS |
1353 | } |
1354 | ||
a542ad1b JS |
1355 | return ret; |
1356 | } | |
1357 | ||
1358 | /* | |
1359 | * calls iterate() for every inode that references the extent identified by | |
4692cf58 | 1360 | * the given parameters. |
a542ad1b JS |
1361 | * when the iterator function returns a non-zero value, iteration stops. |
1362 | */ | |
1363 | int iterate_extent_inodes(struct btrfs_fs_info *fs_info, | |
4692cf58 | 1364 | u64 extent_item_objectid, u64 extent_item_pos, |
7a3ae2f8 | 1365 | int search_commit_root, |
a542ad1b JS |
1366 | iterate_extent_inodes_t *iterate, void *ctx) |
1367 | { | |
a542ad1b | 1368 | int ret; |
a542ad1b JS |
1369 | struct list_head data_refs = LIST_HEAD_INIT(data_refs); |
1370 | struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); | |
4692cf58 | 1371 | struct btrfs_trans_handle *trans; |
7a3ae2f8 JS |
1372 | struct ulist *refs = NULL; |
1373 | struct ulist *roots = NULL; | |
4692cf58 JS |
1374 | struct ulist_node *ref_node = NULL; |
1375 | struct ulist_node *root_node = NULL; | |
8445f61c JS |
1376 | struct seq_list seq_elem = {}; |
1377 | struct seq_list tree_mod_seq_elem = {}; | |
cd1b413c JS |
1378 | struct ulist_iterator ref_uiter; |
1379 | struct ulist_iterator root_uiter; | |
7a3ae2f8 | 1380 | struct btrfs_delayed_ref_root *delayed_refs = NULL; |
a542ad1b | 1381 | |
4692cf58 JS |
1382 | pr_debug("resolving all inodes for extent %llu\n", |
1383 | extent_item_objectid); | |
a542ad1b | 1384 | |
7a3ae2f8 JS |
1385 | if (search_commit_root) { |
1386 | trans = BTRFS_BACKREF_SEARCH_COMMIT_ROOT; | |
1387 | } else { | |
1388 | trans = btrfs_join_transaction(fs_info->extent_root); | |
1389 | if (IS_ERR(trans)) | |
1390 | return PTR_ERR(trans); | |
1391 | ||
1392 | delayed_refs = &trans->transaction->delayed_refs; | |
1393 | spin_lock(&delayed_refs->lock); | |
1394 | btrfs_get_delayed_seq(delayed_refs, &seq_elem); | |
1395 | spin_unlock(&delayed_refs->lock); | |
8445f61c | 1396 | btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
7a3ae2f8 | 1397 | } |
a542ad1b | 1398 | |
4692cf58 | 1399 | ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
8445f61c JS |
1400 | seq_elem.seq, tree_mod_seq_elem.seq, &refs, |
1401 | &extent_item_pos); | |
4692cf58 JS |
1402 | if (ret) |
1403 | goto out; | |
a542ad1b | 1404 | |
cd1b413c JS |
1405 | ULIST_ITER_INIT(&ref_uiter); |
1406 | while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { | |
976b1908 | 1407 | ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, |
8445f61c JS |
1408 | seq_elem.seq, |
1409 | tree_mod_seq_elem.seq, &roots); | |
4692cf58 JS |
1410 | if (ret) |
1411 | break; | |
cd1b413c JS |
1412 | ULIST_ITER_INIT(&root_uiter); |
1413 | while (!ret && (root_node = ulist_next(roots, &root_uiter))) { | |
976b1908 JS |
1414 | pr_debug("root %llu references leaf %llu, data list " |
1415 | "%#lx\n", root_node->val, ref_node->val, | |
1416 | ref_node->aux); | |
1417 | ret = iterate_leaf_refs( | |
1418 | (struct extent_inode_elem *)ref_node->aux, | |
1419 | root_node->val, extent_item_objectid, | |
1420 | iterate, ctx); | |
4692cf58 | 1421 | } |
976b1908 JS |
1422 | ulist_free(roots); |
1423 | roots = NULL; | |
a542ad1b JS |
1424 | } |
1425 | ||
976b1908 | 1426 | free_leaf_list(refs); |
4692cf58 JS |
1427 | ulist_free(roots); |
1428 | out: | |
7a3ae2f8 | 1429 | if (!search_commit_root) { |
8445f61c | 1430 | btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
7a3ae2f8 JS |
1431 | btrfs_put_delayed_seq(delayed_refs, &seq_elem); |
1432 | btrfs_end_transaction(trans, fs_info->extent_root); | |
1433 | } | |
1434 | ||
a542ad1b JS |
1435 | return ret; |
1436 | } | |
1437 | ||
1438 | int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, | |
1439 | struct btrfs_path *path, | |
1440 | iterate_extent_inodes_t *iterate, void *ctx) | |
1441 | { | |
1442 | int ret; | |
4692cf58 | 1443 | u64 extent_item_pos; |
a542ad1b | 1444 | struct btrfs_key found_key; |
7a3ae2f8 | 1445 | int search_commit_root = path->search_commit_root; |
a542ad1b JS |
1446 | |
1447 | ret = extent_from_logical(fs_info, logical, path, | |
1448 | &found_key); | |
4692cf58 | 1449 | btrfs_release_path(path); |
a542ad1b JS |
1450 | if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
1451 | ret = -EINVAL; | |
1452 | if (ret < 0) | |
1453 | return ret; | |
1454 | ||
4692cf58 | 1455 | extent_item_pos = logical - found_key.objectid; |
7a3ae2f8 JS |
1456 | ret = iterate_extent_inodes(fs_info, found_key.objectid, |
1457 | extent_item_pos, search_commit_root, | |
1458 | iterate, ctx); | |
a542ad1b JS |
1459 | |
1460 | return ret; | |
1461 | } | |
1462 | ||
1463 | static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, | |
1464 | struct btrfs_path *path, | |
1465 | iterate_irefs_t *iterate, void *ctx) | |
1466 | { | |
aefc1eb1 | 1467 | int ret = 0; |
a542ad1b JS |
1468 | int slot; |
1469 | u32 cur; | |
1470 | u32 len; | |
1471 | u32 name_len; | |
1472 | u64 parent = 0; | |
1473 | int found = 0; | |
1474 | struct extent_buffer *eb; | |
1475 | struct btrfs_item *item; | |
1476 | struct btrfs_inode_ref *iref; | |
1477 | struct btrfs_key found_key; | |
1478 | ||
aefc1eb1 | 1479 | while (!ret) { |
b916a59a | 1480 | path->leave_spinning = 1; |
a542ad1b JS |
1481 | ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, |
1482 | &found_key); | |
1483 | if (ret < 0) | |
1484 | break; | |
1485 | if (ret) { | |
1486 | ret = found ? 0 : -ENOENT; | |
1487 | break; | |
1488 | } | |
1489 | ++found; | |
1490 | ||
1491 | parent = found_key.offset; | |
1492 | slot = path->slots[0]; | |
1493 | eb = path->nodes[0]; | |
1494 | /* make sure we can use eb after releasing the path */ | |
1495 | atomic_inc(&eb->refs); | |
b916a59a JS |
1496 | btrfs_tree_read_lock(eb); |
1497 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
a542ad1b JS |
1498 | btrfs_release_path(path); |
1499 | ||
1500 | item = btrfs_item_nr(eb, slot); | |
1501 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
1502 | ||
1503 | for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { | |
1504 | name_len = btrfs_inode_ref_name_len(eb, iref); | |
1505 | /* path must be released before calling iterate()! */ | |
4692cf58 JS |
1506 | pr_debug("following ref at offset %u for inode %llu in " |
1507 | "tree %llu\n", cur, | |
1508 | (unsigned long long)found_key.objectid, | |
1509 | (unsigned long long)fs_root->objectid); | |
a542ad1b | 1510 | ret = iterate(parent, iref, eb, ctx); |
aefc1eb1 | 1511 | if (ret) |
a542ad1b | 1512 | break; |
a542ad1b JS |
1513 | len = sizeof(*iref) + name_len; |
1514 | iref = (struct btrfs_inode_ref *)((char *)iref + len); | |
1515 | } | |
b916a59a | 1516 | btrfs_tree_read_unlock_blocking(eb); |
a542ad1b JS |
1517 | free_extent_buffer(eb); |
1518 | } | |
1519 | ||
1520 | btrfs_release_path(path); | |
1521 | ||
1522 | return ret; | |
1523 | } | |
1524 | ||
1525 | /* | |
1526 | * returns 0 if the path could be dumped (probably truncated) | |
1527 | * returns <0 in case of an error | |
1528 | */ | |
1529 | static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref, | |
1530 | struct extent_buffer *eb, void *ctx) | |
1531 | { | |
1532 | struct inode_fs_paths *ipath = ctx; | |
1533 | char *fspath; | |
1534 | char *fspath_min; | |
1535 | int i = ipath->fspath->elem_cnt; | |
1536 | const int s_ptr = sizeof(char *); | |
1537 | u32 bytes_left; | |
1538 | ||
1539 | bytes_left = ipath->fspath->bytes_left > s_ptr ? | |
1540 | ipath->fspath->bytes_left - s_ptr : 0; | |
1541 | ||
740c3d22 | 1542 | fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
a542ad1b JS |
1543 | fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb, |
1544 | inum, fspath_min, bytes_left); | |
1545 | if (IS_ERR(fspath)) | |
1546 | return PTR_ERR(fspath); | |
1547 | ||
1548 | if (fspath > fspath_min) { | |
4692cf58 | 1549 | pr_debug("path resolved: %s\n", fspath); |
745c4d8e | 1550 | ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
a542ad1b JS |
1551 | ++ipath->fspath->elem_cnt; |
1552 | ipath->fspath->bytes_left = fspath - fspath_min; | |
1553 | } else { | |
4692cf58 JS |
1554 | pr_debug("missed path, not enough space. missing bytes: %lu, " |
1555 | "constructed so far: %s\n", | |
1556 | (unsigned long)(fspath_min - fspath), fspath_min); | |
a542ad1b JS |
1557 | ++ipath->fspath->elem_missed; |
1558 | ipath->fspath->bytes_missing += fspath_min - fspath; | |
1559 | ipath->fspath->bytes_left = 0; | |
1560 | } | |
1561 | ||
1562 | return 0; | |
1563 | } | |
1564 | ||
1565 | /* | |
1566 | * this dumps all file system paths to the inode into the ipath struct, provided | |
1567 | * is has been created large enough. each path is zero-terminated and accessed | |
740c3d22 | 1568 | * from ipath->fspath->val[i]. |
a542ad1b | 1569 | * when it returns, there are ipath->fspath->elem_cnt number of paths available |
740c3d22 | 1570 | * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
a542ad1b JS |
1571 | * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, |
1572 | * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would | |
1573 | * have been needed to return all paths. | |
1574 | */ | |
1575 | int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) | |
1576 | { | |
1577 | return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, | |
1578 | inode_to_path, ipath); | |
1579 | } | |
1580 | ||
a542ad1b JS |
1581 | struct btrfs_data_container *init_data_container(u32 total_bytes) |
1582 | { | |
1583 | struct btrfs_data_container *data; | |
1584 | size_t alloc_bytes; | |
1585 | ||
1586 | alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); | |
1587 | data = kmalloc(alloc_bytes, GFP_NOFS); | |
1588 | if (!data) | |
1589 | return ERR_PTR(-ENOMEM); | |
1590 | ||
1591 | if (total_bytes >= sizeof(*data)) { | |
1592 | data->bytes_left = total_bytes - sizeof(*data); | |
1593 | data->bytes_missing = 0; | |
1594 | } else { | |
1595 | data->bytes_missing = sizeof(*data) - total_bytes; | |
1596 | data->bytes_left = 0; | |
1597 | } | |
1598 | ||
1599 | data->elem_cnt = 0; | |
1600 | data->elem_missed = 0; | |
1601 | ||
1602 | return data; | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * allocates space to return multiple file system paths for an inode. | |
1607 | * total_bytes to allocate are passed, note that space usable for actual path | |
1608 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1609 | * the returned pointer must be freed with free_ipath() in the end. | |
1610 | */ | |
1611 | struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, | |
1612 | struct btrfs_path *path) | |
1613 | { | |
1614 | struct inode_fs_paths *ifp; | |
1615 | struct btrfs_data_container *fspath; | |
1616 | ||
1617 | fspath = init_data_container(total_bytes); | |
1618 | if (IS_ERR(fspath)) | |
1619 | return (void *)fspath; | |
1620 | ||
1621 | ifp = kmalloc(sizeof(*ifp), GFP_NOFS); | |
1622 | if (!ifp) { | |
1623 | kfree(fspath); | |
1624 | return ERR_PTR(-ENOMEM); | |
1625 | } | |
1626 | ||
1627 | ifp->btrfs_path = path; | |
1628 | ifp->fspath = fspath; | |
1629 | ifp->fs_root = fs_root; | |
1630 | ||
1631 | return ifp; | |
1632 | } | |
1633 | ||
1634 | void free_ipath(struct inode_fs_paths *ipath) | |
1635 | { | |
4735fb28 JJ |
1636 | if (!ipath) |
1637 | return; | |
5eb56d25 | 1638 | kfree(ipath->fspath); |
a542ad1b JS |
1639 | kfree(ipath); |
1640 | } |