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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 | ||
425d17a2 | 19 | #include <linux/vmalloc.h> |
a542ad1b JS |
20 | #include "ctree.h" |
21 | #include "disk-io.h" | |
22 | #include "backref.h" | |
8da6d581 JS |
23 | #include "ulist.h" |
24 | #include "transaction.h" | |
25 | #include "delayed-ref.h" | |
b916a59a | 26 | #include "locking.h" |
a542ad1b | 27 | |
976b1908 JS |
28 | struct extent_inode_elem { |
29 | u64 inum; | |
30 | u64 offset; | |
31 | struct extent_inode_elem *next; | |
32 | }; | |
33 | ||
34 | static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, | |
35 | struct btrfs_file_extent_item *fi, | |
36 | u64 extent_item_pos, | |
37 | struct extent_inode_elem **eie) | |
38 | { | |
39 | u64 data_offset; | |
40 | u64 data_len; | |
41 | struct extent_inode_elem *e; | |
42 | ||
43 | data_offset = btrfs_file_extent_offset(eb, fi); | |
44 | data_len = btrfs_file_extent_num_bytes(eb, fi); | |
45 | ||
46 | if (extent_item_pos < data_offset || | |
47 | extent_item_pos >= data_offset + data_len) | |
48 | return 1; | |
49 | ||
50 | e = kmalloc(sizeof(*e), GFP_NOFS); | |
51 | if (!e) | |
52 | return -ENOMEM; | |
53 | ||
54 | e->next = *eie; | |
55 | e->inum = key->objectid; | |
56 | e->offset = key->offset + (extent_item_pos - data_offset); | |
57 | *eie = e; | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
62 | static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte, | |
63 | u64 extent_item_pos, | |
64 | struct extent_inode_elem **eie) | |
65 | { | |
66 | u64 disk_byte; | |
67 | struct btrfs_key key; | |
68 | struct btrfs_file_extent_item *fi; | |
69 | int slot; | |
70 | int nritems; | |
71 | int extent_type; | |
72 | int ret; | |
73 | ||
74 | /* | |
75 | * from the shared data ref, we only have the leaf but we need | |
76 | * the key. thus, we must look into all items and see that we | |
77 | * find one (some) with a reference to our extent item. | |
78 | */ | |
79 | nritems = btrfs_header_nritems(eb); | |
80 | for (slot = 0; slot < nritems; ++slot) { | |
81 | btrfs_item_key_to_cpu(eb, &key, slot); | |
82 | if (key.type != BTRFS_EXTENT_DATA_KEY) | |
83 | continue; | |
84 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
85 | extent_type = btrfs_file_extent_type(eb, fi); | |
86 | if (extent_type == BTRFS_FILE_EXTENT_INLINE) | |
87 | continue; | |
88 | /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ | |
89 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
90 | if (disk_byte != wanted_disk_byte) | |
91 | continue; | |
92 | ||
93 | ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie); | |
94 | if (ret < 0) | |
95 | return ret; | |
96 | } | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
8da6d581 JS |
101 | /* |
102 | * this structure records all encountered refs on the way up to the root | |
103 | */ | |
104 | struct __prelim_ref { | |
105 | struct list_head list; | |
106 | u64 root_id; | |
d5c88b73 | 107 | struct btrfs_key key_for_search; |
8da6d581 JS |
108 | int level; |
109 | int count; | |
3301958b | 110 | struct extent_inode_elem *inode_list; |
8da6d581 JS |
111 | u64 parent; |
112 | u64 wanted_disk_byte; | |
113 | }; | |
114 | ||
d5c88b73 JS |
115 | /* |
116 | * the rules for all callers of this function are: | |
117 | * - obtaining the parent is the goal | |
118 | * - if you add a key, you must know that it is a correct key | |
119 | * - if you cannot add the parent or a correct key, then we will look into the | |
120 | * block later to set a correct key | |
121 | * | |
122 | * delayed refs | |
123 | * ============ | |
124 | * backref type | shared | indirect | shared | indirect | |
125 | * information | tree | tree | data | data | |
126 | * --------------------+--------+----------+--------+---------- | |
127 | * parent logical | y | - | - | - | |
128 | * key to resolve | - | y | y | y | |
129 | * tree block logical | - | - | - | - | |
130 | * root for resolving | y | y | y | y | |
131 | * | |
132 | * - column 1: we've the parent -> done | |
133 | * - column 2, 3, 4: we use the key to find the parent | |
134 | * | |
135 | * on disk refs (inline or keyed) | |
136 | * ============================== | |
137 | * backref type | shared | indirect | shared | indirect | |
138 | * information | tree | tree | data | data | |
139 | * --------------------+--------+----------+--------+---------- | |
140 | * parent logical | y | - | y | - | |
141 | * key to resolve | - | - | - | y | |
142 | * tree block logical | y | y | y | y | |
143 | * root for resolving | - | y | y | y | |
144 | * | |
145 | * - column 1, 3: we've the parent -> done | |
146 | * - column 2: we take the first key from the block to find the parent | |
147 | * (see __add_missing_keys) | |
148 | * - column 4: we use the key to find the parent | |
149 | * | |
150 | * additional information that's available but not required to find the parent | |
151 | * block might help in merging entries to gain some speed. | |
152 | */ | |
153 | ||
8da6d581 | 154 | static int __add_prelim_ref(struct list_head *head, u64 root_id, |
d5c88b73 JS |
155 | struct btrfs_key *key, int level, |
156 | u64 parent, u64 wanted_disk_byte, int count) | |
8da6d581 JS |
157 | { |
158 | struct __prelim_ref *ref; | |
159 | ||
160 | /* in case we're adding delayed refs, we're holding the refs spinlock */ | |
161 | ref = kmalloc(sizeof(*ref), GFP_ATOMIC); | |
162 | if (!ref) | |
163 | return -ENOMEM; | |
164 | ||
165 | ref->root_id = root_id; | |
166 | if (key) | |
d5c88b73 | 167 | ref->key_for_search = *key; |
8da6d581 | 168 | else |
d5c88b73 | 169 | memset(&ref->key_for_search, 0, sizeof(ref->key_for_search)); |
8da6d581 | 170 | |
3301958b | 171 | ref->inode_list = NULL; |
8da6d581 JS |
172 | ref->level = level; |
173 | ref->count = count; | |
174 | ref->parent = parent; | |
175 | ref->wanted_disk_byte = wanted_disk_byte; | |
176 | list_add_tail(&ref->list, head); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, | |
976b1908 | 182 | struct ulist *parents, int level, |
69bca40d | 183 | struct btrfs_key *key_for_search, u64 time_seq, |
3d7806ec | 184 | u64 wanted_disk_byte, |
976b1908 | 185 | const u64 *extent_item_pos) |
8da6d581 | 186 | { |
69bca40d AB |
187 | int ret = 0; |
188 | int slot; | |
189 | struct extent_buffer *eb; | |
190 | struct btrfs_key key; | |
8da6d581 | 191 | struct btrfs_file_extent_item *fi; |
3301958b | 192 | struct extent_inode_elem *eie = NULL; |
8da6d581 JS |
193 | u64 disk_byte; |
194 | ||
69bca40d AB |
195 | if (level != 0) { |
196 | eb = path->nodes[level]; | |
197 | ret = ulist_add(parents, eb->start, 0, GFP_NOFS); | |
3301958b JS |
198 | if (ret < 0) |
199 | return ret; | |
8da6d581 | 200 | return 0; |
69bca40d | 201 | } |
8da6d581 JS |
202 | |
203 | /* | |
69bca40d AB |
204 | * We normally enter this function with the path already pointing to |
205 | * the first item to check. But sometimes, we may enter it with | |
206 | * slot==nritems. In that case, go to the next leaf before we continue. | |
8da6d581 | 207 | */ |
69bca40d | 208 | if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) |
3d7806ec | 209 | ret = btrfs_next_old_leaf(root, path, time_seq); |
8da6d581 | 210 | |
69bca40d | 211 | while (!ret) { |
8da6d581 | 212 | eb = path->nodes[0]; |
69bca40d AB |
213 | slot = path->slots[0]; |
214 | ||
215 | btrfs_item_key_to_cpu(eb, &key, slot); | |
216 | ||
217 | if (key.objectid != key_for_search->objectid || | |
218 | key.type != BTRFS_EXTENT_DATA_KEY) | |
219 | break; | |
220 | ||
221 | fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); | |
222 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); | |
223 | ||
224 | if (disk_byte == wanted_disk_byte) { | |
225 | eie = NULL; | |
226 | if (extent_item_pos) { | |
227 | ret = check_extent_in_eb(&key, eb, fi, | |
228 | *extent_item_pos, | |
229 | &eie); | |
230 | if (ret < 0) | |
231 | break; | |
232 | } | |
233 | if (!ret) { | |
234 | ret = ulist_add(parents, eb->start, | |
995e01b7 | 235 | (uintptr_t)eie, GFP_NOFS); |
69bca40d AB |
236 | if (ret < 0) |
237 | break; | |
238 | if (!extent_item_pos) { | |
239 | ret = btrfs_next_old_leaf(root, path, | |
240 | time_seq); | |
241 | continue; | |
242 | } | |
243 | } | |
8da6d581 | 244 | } |
69bca40d | 245 | ret = btrfs_next_old_item(root, path, time_seq); |
8da6d581 JS |
246 | } |
247 | ||
69bca40d AB |
248 | if (ret > 0) |
249 | ret = 0; | |
250 | return ret; | |
8da6d581 JS |
251 | } |
252 | ||
253 | /* | |
254 | * resolve an indirect backref in the form (root_id, key, level) | |
255 | * to a logical address | |
256 | */ | |
257 | static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, | |
7a3ae2f8 | 258 | int search_commit_root, |
8445f61c | 259 | u64 time_seq, |
8da6d581 | 260 | struct __prelim_ref *ref, |
976b1908 JS |
261 | struct ulist *parents, |
262 | const u64 *extent_item_pos) | |
8da6d581 JS |
263 | { |
264 | struct btrfs_path *path; | |
265 | struct btrfs_root *root; | |
266 | struct btrfs_key root_key; | |
8da6d581 JS |
267 | struct extent_buffer *eb; |
268 | int ret = 0; | |
269 | int root_level; | |
270 | int level = ref->level; | |
271 | ||
272 | path = btrfs_alloc_path(); | |
273 | if (!path) | |
274 | return -ENOMEM; | |
7a3ae2f8 | 275 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
276 | |
277 | root_key.objectid = ref->root_id; | |
278 | root_key.type = BTRFS_ROOT_ITEM_KEY; | |
279 | root_key.offset = (u64)-1; | |
280 | root = btrfs_read_fs_root_no_name(fs_info, &root_key); | |
281 | if (IS_ERR(root)) { | |
282 | ret = PTR_ERR(root); | |
283 | goto out; | |
284 | } | |
285 | ||
286 | rcu_read_lock(); | |
287 | root_level = btrfs_header_level(root->node); | |
288 | rcu_read_unlock(); | |
289 | ||
290 | if (root_level + 1 == level) | |
291 | goto out; | |
292 | ||
293 | path->lowest_level = level; | |
8445f61c | 294 | ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq); |
8da6d581 JS |
295 | pr_debug("search slot in root %llu (level %d, ref count %d) returned " |
296 | "%d for key (%llu %u %llu)\n", | |
297 | (unsigned long long)ref->root_id, level, ref->count, ret, | |
d5c88b73 JS |
298 | (unsigned long long)ref->key_for_search.objectid, |
299 | ref->key_for_search.type, | |
300 | (unsigned long long)ref->key_for_search.offset); | |
8da6d581 JS |
301 | if (ret < 0) |
302 | goto out; | |
303 | ||
304 | eb = path->nodes[level]; | |
9345457f JS |
305 | while (!eb) { |
306 | if (!level) { | |
307 | WARN_ON(1); | |
308 | ret = 1; | |
309 | goto out; | |
310 | } | |
311 | level--; | |
312 | eb = path->nodes[level]; | |
8da6d581 JS |
313 | } |
314 | ||
69bca40d AB |
315 | ret = add_all_parents(root, path, parents, level, &ref->key_for_search, |
316 | time_seq, ref->wanted_disk_byte, | |
317 | extent_item_pos); | |
8da6d581 JS |
318 | out: |
319 | btrfs_free_path(path); | |
320 | return ret; | |
321 | } | |
322 | ||
323 | /* | |
324 | * resolve all indirect backrefs from the list | |
325 | */ | |
326 | static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, | |
8445f61c | 327 | int search_commit_root, u64 time_seq, |
976b1908 JS |
328 | struct list_head *head, |
329 | const u64 *extent_item_pos) | |
8da6d581 JS |
330 | { |
331 | int err; | |
332 | int ret = 0; | |
333 | struct __prelim_ref *ref; | |
334 | struct __prelim_ref *ref_safe; | |
335 | struct __prelim_ref *new_ref; | |
336 | struct ulist *parents; | |
337 | struct ulist_node *node; | |
cd1b413c | 338 | struct ulist_iterator uiter; |
8da6d581 JS |
339 | |
340 | parents = ulist_alloc(GFP_NOFS); | |
341 | if (!parents) | |
342 | return -ENOMEM; | |
343 | ||
344 | /* | |
345 | * _safe allows us to insert directly after the current item without | |
346 | * iterating over the newly inserted items. | |
347 | * we're also allowed to re-assign ref during iteration. | |
348 | */ | |
349 | list_for_each_entry_safe(ref, ref_safe, head, list) { | |
350 | if (ref->parent) /* already direct */ | |
351 | continue; | |
352 | if (ref->count == 0) | |
353 | continue; | |
7a3ae2f8 | 354 | err = __resolve_indirect_ref(fs_info, search_commit_root, |
8445f61c JS |
355 | time_seq, ref, parents, |
356 | extent_item_pos); | |
8da6d581 JS |
357 | if (err) { |
358 | if (ret == 0) | |
359 | ret = err; | |
360 | continue; | |
361 | } | |
362 | ||
363 | /* we put the first parent into the ref at hand */ | |
cd1b413c JS |
364 | ULIST_ITER_INIT(&uiter); |
365 | node = ulist_next(parents, &uiter); | |
8da6d581 | 366 | ref->parent = node ? node->val : 0; |
995e01b7 JS |
367 | ref->inode_list = node ? |
368 | (struct extent_inode_elem *)(uintptr_t)node->aux : 0; | |
8da6d581 JS |
369 | |
370 | /* additional parents require new refs being added here */ | |
cd1b413c | 371 | while ((node = ulist_next(parents, &uiter))) { |
8da6d581 JS |
372 | new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); |
373 | if (!new_ref) { | |
374 | ret = -ENOMEM; | |
375 | break; | |
376 | } | |
377 | memcpy(new_ref, ref, sizeof(*ref)); | |
378 | new_ref->parent = node->val; | |
995e01b7 JS |
379 | new_ref->inode_list = (struct extent_inode_elem *) |
380 | (uintptr_t)node->aux; | |
8da6d581 JS |
381 | list_add(&new_ref->list, &ref->list); |
382 | } | |
383 | ulist_reinit(parents); | |
384 | } | |
385 | ||
386 | ulist_free(parents); | |
387 | return ret; | |
388 | } | |
389 | ||
d5c88b73 JS |
390 | static inline int ref_for_same_block(struct __prelim_ref *ref1, |
391 | struct __prelim_ref *ref2) | |
392 | { | |
393 | if (ref1->level != ref2->level) | |
394 | return 0; | |
395 | if (ref1->root_id != ref2->root_id) | |
396 | return 0; | |
397 | if (ref1->key_for_search.type != ref2->key_for_search.type) | |
398 | return 0; | |
399 | if (ref1->key_for_search.objectid != ref2->key_for_search.objectid) | |
400 | return 0; | |
401 | if (ref1->key_for_search.offset != ref2->key_for_search.offset) | |
402 | return 0; | |
403 | if (ref1->parent != ref2->parent) | |
404 | return 0; | |
405 | ||
406 | return 1; | |
407 | } | |
408 | ||
409 | /* | |
410 | * read tree blocks and add keys where required. | |
411 | */ | |
412 | static int __add_missing_keys(struct btrfs_fs_info *fs_info, | |
413 | struct list_head *head) | |
414 | { | |
415 | struct list_head *pos; | |
416 | struct extent_buffer *eb; | |
417 | ||
418 | list_for_each(pos, head) { | |
419 | struct __prelim_ref *ref; | |
420 | ref = list_entry(pos, struct __prelim_ref, list); | |
421 | ||
422 | if (ref->parent) | |
423 | continue; | |
424 | if (ref->key_for_search.type) | |
425 | continue; | |
426 | BUG_ON(!ref->wanted_disk_byte); | |
427 | eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte, | |
428 | fs_info->tree_root->leafsize, 0); | |
429 | BUG_ON(!eb); | |
430 | btrfs_tree_read_lock(eb); | |
431 | if (btrfs_header_level(eb) == 0) | |
432 | btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0); | |
433 | else | |
434 | btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0); | |
435 | btrfs_tree_read_unlock(eb); | |
436 | free_extent_buffer(eb); | |
437 | } | |
438 | return 0; | |
439 | } | |
440 | ||
8da6d581 JS |
441 | /* |
442 | * merge two lists of backrefs and adjust counts accordingly | |
443 | * | |
444 | * mode = 1: merge identical keys, if key is set | |
d5c88b73 JS |
445 | * FIXME: if we add more keys in __add_prelim_ref, we can merge more here. |
446 | * additionally, we could even add a key range for the blocks we | |
447 | * looked into to merge even more (-> replace unresolved refs by those | |
448 | * having a parent). | |
8da6d581 JS |
449 | * mode = 2: merge identical parents |
450 | */ | |
451 | static int __merge_refs(struct list_head *head, int mode) | |
452 | { | |
453 | struct list_head *pos1; | |
454 | ||
455 | list_for_each(pos1, head) { | |
456 | struct list_head *n2; | |
457 | struct list_head *pos2; | |
458 | struct __prelim_ref *ref1; | |
459 | ||
460 | ref1 = list_entry(pos1, struct __prelim_ref, list); | |
461 | ||
8da6d581 JS |
462 | for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; |
463 | pos2 = n2, n2 = pos2->next) { | |
464 | struct __prelim_ref *ref2; | |
d5c88b73 | 465 | struct __prelim_ref *xchg; |
8da6d581 JS |
466 | |
467 | ref2 = list_entry(pos2, struct __prelim_ref, list); | |
468 | ||
469 | if (mode == 1) { | |
d5c88b73 | 470 | if (!ref_for_same_block(ref1, ref2)) |
8da6d581 | 471 | continue; |
d5c88b73 JS |
472 | if (!ref1->parent && ref2->parent) { |
473 | xchg = ref1; | |
474 | ref1 = ref2; | |
475 | ref2 = xchg; | |
476 | } | |
8da6d581 JS |
477 | ref1->count += ref2->count; |
478 | } else { | |
479 | if (ref1->parent != ref2->parent) | |
480 | continue; | |
481 | ref1->count += ref2->count; | |
482 | } | |
483 | list_del(&ref2->list); | |
484 | kfree(ref2); | |
485 | } | |
486 | ||
487 | } | |
488 | return 0; | |
489 | } | |
490 | ||
491 | /* | |
492 | * add all currently queued delayed refs from this head whose seq nr is | |
493 | * smaller or equal that seq to the list | |
494 | */ | |
495 | static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, | |
8da6d581 JS |
496 | struct list_head *prefs) |
497 | { | |
498 | struct btrfs_delayed_extent_op *extent_op = head->extent_op; | |
499 | struct rb_node *n = &head->node.rb_node; | |
d5c88b73 JS |
500 | struct btrfs_key key; |
501 | struct btrfs_key op_key = {0}; | |
8da6d581 | 502 | int sgn; |
b1375d64 | 503 | int ret = 0; |
8da6d581 JS |
504 | |
505 | if (extent_op && extent_op->update_key) | |
d5c88b73 | 506 | btrfs_disk_key_to_cpu(&op_key, &extent_op->key); |
8da6d581 JS |
507 | |
508 | while ((n = rb_prev(n))) { | |
509 | struct btrfs_delayed_ref_node *node; | |
510 | node = rb_entry(n, struct btrfs_delayed_ref_node, | |
511 | rb_node); | |
512 | if (node->bytenr != head->node.bytenr) | |
513 | break; | |
514 | WARN_ON(node->is_head); | |
515 | ||
516 | if (node->seq > seq) | |
517 | continue; | |
518 | ||
519 | switch (node->action) { | |
520 | case BTRFS_ADD_DELAYED_EXTENT: | |
521 | case BTRFS_UPDATE_DELAYED_HEAD: | |
522 | WARN_ON(1); | |
523 | continue; | |
524 | case BTRFS_ADD_DELAYED_REF: | |
525 | sgn = 1; | |
526 | break; | |
527 | case BTRFS_DROP_DELAYED_REF: | |
528 | sgn = -1; | |
529 | break; | |
530 | default: | |
531 | BUG_ON(1); | |
532 | } | |
533 | switch (node->type) { | |
534 | case BTRFS_TREE_BLOCK_REF_KEY: { | |
535 | struct btrfs_delayed_tree_ref *ref; | |
536 | ||
537 | ref = btrfs_delayed_node_to_tree_ref(node); | |
d5c88b73 | 538 | ret = __add_prelim_ref(prefs, ref->root, &op_key, |
8da6d581 JS |
539 | ref->level + 1, 0, node->bytenr, |
540 | node->ref_mod * sgn); | |
541 | break; | |
542 | } | |
543 | case BTRFS_SHARED_BLOCK_REF_KEY: { | |
544 | struct btrfs_delayed_tree_ref *ref; | |
545 | ||
546 | ref = btrfs_delayed_node_to_tree_ref(node); | |
d5c88b73 | 547 | ret = __add_prelim_ref(prefs, ref->root, NULL, |
8da6d581 JS |
548 | ref->level + 1, ref->parent, |
549 | node->bytenr, | |
550 | node->ref_mod * sgn); | |
551 | break; | |
552 | } | |
553 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
554 | struct btrfs_delayed_data_ref *ref; | |
8da6d581 JS |
555 | ref = btrfs_delayed_node_to_data_ref(node); |
556 | ||
557 | key.objectid = ref->objectid; | |
558 | key.type = BTRFS_EXTENT_DATA_KEY; | |
559 | key.offset = ref->offset; | |
560 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, | |
561 | node->bytenr, | |
562 | node->ref_mod * sgn); | |
563 | break; | |
564 | } | |
565 | case BTRFS_SHARED_DATA_REF_KEY: { | |
566 | struct btrfs_delayed_data_ref *ref; | |
8da6d581 JS |
567 | |
568 | ref = btrfs_delayed_node_to_data_ref(node); | |
569 | ||
570 | key.objectid = ref->objectid; | |
571 | key.type = BTRFS_EXTENT_DATA_KEY; | |
572 | key.offset = ref->offset; | |
573 | ret = __add_prelim_ref(prefs, ref->root, &key, 0, | |
574 | ref->parent, node->bytenr, | |
575 | node->ref_mod * sgn); | |
576 | break; | |
577 | } | |
578 | default: | |
579 | WARN_ON(1); | |
580 | } | |
581 | BUG_ON(ret); | |
582 | } | |
583 | ||
584 | return 0; | |
585 | } | |
586 | ||
587 | /* | |
588 | * add all inline backrefs for bytenr to the list | |
589 | */ | |
590 | static int __add_inline_refs(struct btrfs_fs_info *fs_info, | |
591 | struct btrfs_path *path, u64 bytenr, | |
d5c88b73 | 592 | int *info_level, struct list_head *prefs) |
8da6d581 | 593 | { |
b1375d64 | 594 | int ret = 0; |
8da6d581 JS |
595 | int slot; |
596 | struct extent_buffer *leaf; | |
597 | struct btrfs_key key; | |
598 | unsigned long ptr; | |
599 | unsigned long end; | |
600 | struct btrfs_extent_item *ei; | |
601 | u64 flags; | |
602 | u64 item_size; | |
603 | ||
604 | /* | |
605 | * enumerate all inline refs | |
606 | */ | |
607 | leaf = path->nodes[0]; | |
dadcaf78 | 608 | slot = path->slots[0]; |
8da6d581 JS |
609 | |
610 | item_size = btrfs_item_size_nr(leaf, slot); | |
611 | BUG_ON(item_size < sizeof(*ei)); | |
612 | ||
613 | ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); | |
614 | flags = btrfs_extent_flags(leaf, ei); | |
615 | ||
616 | ptr = (unsigned long)(ei + 1); | |
617 | end = (unsigned long)ei + item_size; | |
618 | ||
619 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
620 | struct btrfs_tree_block_info *info; | |
8da6d581 JS |
621 | |
622 | info = (struct btrfs_tree_block_info *)ptr; | |
623 | *info_level = btrfs_tree_block_level(leaf, info); | |
8da6d581 JS |
624 | ptr += sizeof(struct btrfs_tree_block_info); |
625 | BUG_ON(ptr > end); | |
626 | } else { | |
627 | BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); | |
628 | } | |
629 | ||
630 | while (ptr < end) { | |
631 | struct btrfs_extent_inline_ref *iref; | |
632 | u64 offset; | |
633 | int type; | |
634 | ||
635 | iref = (struct btrfs_extent_inline_ref *)ptr; | |
636 | type = btrfs_extent_inline_ref_type(leaf, iref); | |
637 | offset = btrfs_extent_inline_ref_offset(leaf, iref); | |
638 | ||
639 | switch (type) { | |
640 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
d5c88b73 | 641 | ret = __add_prelim_ref(prefs, 0, NULL, |
8da6d581 JS |
642 | *info_level + 1, offset, |
643 | bytenr, 1); | |
644 | break; | |
645 | case BTRFS_SHARED_DATA_REF_KEY: { | |
646 | struct btrfs_shared_data_ref *sdref; | |
647 | int count; | |
648 | ||
649 | sdref = (struct btrfs_shared_data_ref *)(iref + 1); | |
650 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
651 | ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, | |
652 | bytenr, count); | |
653 | break; | |
654 | } | |
655 | case BTRFS_TREE_BLOCK_REF_KEY: | |
d5c88b73 JS |
656 | ret = __add_prelim_ref(prefs, offset, NULL, |
657 | *info_level + 1, 0, | |
658 | bytenr, 1); | |
8da6d581 JS |
659 | break; |
660 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
661 | struct btrfs_extent_data_ref *dref; | |
662 | int count; | |
663 | u64 root; | |
664 | ||
665 | dref = (struct btrfs_extent_data_ref *)(&iref->offset); | |
666 | count = btrfs_extent_data_ref_count(leaf, dref); | |
667 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
668 | dref); | |
669 | key.type = BTRFS_EXTENT_DATA_KEY; | |
670 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
671 | root = btrfs_extent_data_ref_root(leaf, dref); | |
d5c88b73 JS |
672 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, |
673 | bytenr, count); | |
8da6d581 JS |
674 | break; |
675 | } | |
676 | default: | |
677 | WARN_ON(1); | |
678 | } | |
679 | BUG_ON(ret); | |
680 | ptr += btrfs_extent_inline_ref_size(type); | |
681 | } | |
682 | ||
683 | return 0; | |
684 | } | |
685 | ||
686 | /* | |
687 | * add all non-inline backrefs for bytenr to the list | |
688 | */ | |
689 | static int __add_keyed_refs(struct btrfs_fs_info *fs_info, | |
690 | struct btrfs_path *path, u64 bytenr, | |
d5c88b73 | 691 | int info_level, struct list_head *prefs) |
8da6d581 JS |
692 | { |
693 | struct btrfs_root *extent_root = fs_info->extent_root; | |
694 | int ret; | |
695 | int slot; | |
696 | struct extent_buffer *leaf; | |
697 | struct btrfs_key key; | |
698 | ||
699 | while (1) { | |
700 | ret = btrfs_next_item(extent_root, path); | |
701 | if (ret < 0) | |
702 | break; | |
703 | if (ret) { | |
704 | ret = 0; | |
705 | break; | |
706 | } | |
707 | ||
708 | slot = path->slots[0]; | |
709 | leaf = path->nodes[0]; | |
710 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
711 | ||
712 | if (key.objectid != bytenr) | |
713 | break; | |
714 | if (key.type < BTRFS_TREE_BLOCK_REF_KEY) | |
715 | continue; | |
716 | if (key.type > BTRFS_SHARED_DATA_REF_KEY) | |
717 | break; | |
718 | ||
719 | switch (key.type) { | |
720 | case BTRFS_SHARED_BLOCK_REF_KEY: | |
d5c88b73 | 721 | ret = __add_prelim_ref(prefs, 0, NULL, |
8da6d581 JS |
722 | info_level + 1, key.offset, |
723 | bytenr, 1); | |
724 | break; | |
725 | case BTRFS_SHARED_DATA_REF_KEY: { | |
726 | struct btrfs_shared_data_ref *sdref; | |
727 | int count; | |
728 | ||
729 | sdref = btrfs_item_ptr(leaf, slot, | |
730 | struct btrfs_shared_data_ref); | |
731 | count = btrfs_shared_data_ref_count(leaf, sdref); | |
732 | ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, | |
733 | bytenr, count); | |
734 | break; | |
735 | } | |
736 | case BTRFS_TREE_BLOCK_REF_KEY: | |
d5c88b73 JS |
737 | ret = __add_prelim_ref(prefs, key.offset, NULL, |
738 | info_level + 1, 0, | |
739 | bytenr, 1); | |
8da6d581 JS |
740 | break; |
741 | case BTRFS_EXTENT_DATA_REF_KEY: { | |
742 | struct btrfs_extent_data_ref *dref; | |
743 | int count; | |
744 | u64 root; | |
745 | ||
746 | dref = btrfs_item_ptr(leaf, slot, | |
747 | struct btrfs_extent_data_ref); | |
748 | count = btrfs_extent_data_ref_count(leaf, dref); | |
749 | key.objectid = btrfs_extent_data_ref_objectid(leaf, | |
750 | dref); | |
751 | key.type = BTRFS_EXTENT_DATA_KEY; | |
752 | key.offset = btrfs_extent_data_ref_offset(leaf, dref); | |
753 | root = btrfs_extent_data_ref_root(leaf, dref); | |
754 | ret = __add_prelim_ref(prefs, root, &key, 0, 0, | |
d5c88b73 | 755 | bytenr, count); |
8da6d581 JS |
756 | break; |
757 | } | |
758 | default: | |
759 | WARN_ON(1); | |
760 | } | |
761 | BUG_ON(ret); | |
762 | } | |
763 | ||
764 | return ret; | |
765 | } | |
766 | ||
767 | /* | |
768 | * this adds all existing backrefs (inline backrefs, backrefs and delayed | |
769 | * refs) for the given bytenr to the refs list, merges duplicates and resolves | |
770 | * indirect refs to their parent bytenr. | |
771 | * When roots are found, they're added to the roots list | |
772 | * | |
773 | * FIXME some caching might speed things up | |
774 | */ | |
775 | static int find_parent_nodes(struct btrfs_trans_handle *trans, | |
776 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
097b8a7c JS |
777 | u64 time_seq, struct ulist *refs, |
778 | struct ulist *roots, const u64 *extent_item_pos) | |
8da6d581 JS |
779 | { |
780 | struct btrfs_key key; | |
781 | struct btrfs_path *path; | |
8da6d581 | 782 | struct btrfs_delayed_ref_root *delayed_refs = NULL; |
d3b01064 | 783 | struct btrfs_delayed_ref_head *head; |
8da6d581 JS |
784 | int info_level = 0; |
785 | int ret; | |
7a3ae2f8 | 786 | int search_commit_root = (trans == BTRFS_BACKREF_SEARCH_COMMIT_ROOT); |
8da6d581 JS |
787 | struct list_head prefs_delayed; |
788 | struct list_head prefs; | |
789 | struct __prelim_ref *ref; | |
790 | ||
791 | INIT_LIST_HEAD(&prefs); | |
792 | INIT_LIST_HEAD(&prefs_delayed); | |
793 | ||
794 | key.objectid = bytenr; | |
795 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
796 | key.offset = (u64)-1; | |
797 | ||
798 | path = btrfs_alloc_path(); | |
799 | if (!path) | |
800 | return -ENOMEM; | |
7a3ae2f8 | 801 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
802 | |
803 | /* | |
804 | * grab both a lock on the path and a lock on the delayed ref head. | |
805 | * We need both to get a consistent picture of how the refs look | |
806 | * at a specified point in time | |
807 | */ | |
808 | again: | |
d3b01064 LZ |
809 | head = NULL; |
810 | ||
8da6d581 JS |
811 | ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); |
812 | if (ret < 0) | |
813 | goto out; | |
814 | BUG_ON(ret == 0); | |
815 | ||
7a3ae2f8 JS |
816 | if (trans != BTRFS_BACKREF_SEARCH_COMMIT_ROOT) { |
817 | /* | |
818 | * look if there are updates for this ref queued and lock the | |
819 | * head | |
820 | */ | |
821 | delayed_refs = &trans->transaction->delayed_refs; | |
822 | spin_lock(&delayed_refs->lock); | |
823 | head = btrfs_find_delayed_ref_head(trans, bytenr); | |
824 | if (head) { | |
825 | if (!mutex_trylock(&head->mutex)) { | |
826 | atomic_inc(&head->node.refs); | |
827 | spin_unlock(&delayed_refs->lock); | |
828 | ||
829 | btrfs_release_path(path); | |
830 | ||
831 | /* | |
832 | * Mutex was contended, block until it's | |
833 | * released and try again | |
834 | */ | |
835 | mutex_lock(&head->mutex); | |
836 | mutex_unlock(&head->mutex); | |
837 | btrfs_put_delayed_ref(&head->node); | |
838 | goto again; | |
839 | } | |
097b8a7c | 840 | ret = __add_delayed_refs(head, time_seq, |
8445f61c | 841 | &prefs_delayed); |
155725c9 | 842 | mutex_unlock(&head->mutex); |
7a3ae2f8 JS |
843 | if (ret) { |
844 | spin_unlock(&delayed_refs->lock); | |
845 | goto out; | |
846 | } | |
d3b01064 | 847 | } |
7a3ae2f8 | 848 | spin_unlock(&delayed_refs->lock); |
8da6d581 | 849 | } |
8da6d581 JS |
850 | |
851 | if (path->slots[0]) { | |
852 | struct extent_buffer *leaf; | |
853 | int slot; | |
854 | ||
dadcaf78 | 855 | path->slots[0]--; |
8da6d581 | 856 | leaf = path->nodes[0]; |
dadcaf78 | 857 | slot = path->slots[0]; |
8da6d581 JS |
858 | btrfs_item_key_to_cpu(leaf, &key, slot); |
859 | if (key.objectid == bytenr && | |
860 | key.type == BTRFS_EXTENT_ITEM_KEY) { | |
861 | ret = __add_inline_refs(fs_info, path, bytenr, | |
d5c88b73 | 862 | &info_level, &prefs); |
8da6d581 JS |
863 | if (ret) |
864 | goto out; | |
d5c88b73 | 865 | ret = __add_keyed_refs(fs_info, path, bytenr, |
8da6d581 JS |
866 | info_level, &prefs); |
867 | if (ret) | |
868 | goto out; | |
869 | } | |
870 | } | |
871 | btrfs_release_path(path); | |
872 | ||
8da6d581 JS |
873 | list_splice_init(&prefs_delayed, &prefs); |
874 | ||
d5c88b73 JS |
875 | ret = __add_missing_keys(fs_info, &prefs); |
876 | if (ret) | |
877 | goto out; | |
878 | ||
8da6d581 JS |
879 | ret = __merge_refs(&prefs, 1); |
880 | if (ret) | |
881 | goto out; | |
882 | ||
8445f61c JS |
883 | ret = __resolve_indirect_refs(fs_info, search_commit_root, time_seq, |
884 | &prefs, extent_item_pos); | |
8da6d581 JS |
885 | if (ret) |
886 | goto out; | |
887 | ||
888 | ret = __merge_refs(&prefs, 2); | |
889 | if (ret) | |
890 | goto out; | |
891 | ||
892 | while (!list_empty(&prefs)) { | |
893 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
894 | list_del(&ref->list); | |
895 | if (ref->count < 0) | |
896 | WARN_ON(1); | |
897 | if (ref->count && ref->root_id && ref->parent == 0) { | |
898 | /* no parent == root of tree */ | |
899 | ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); | |
900 | BUG_ON(ret < 0); | |
901 | } | |
902 | if (ref->count && ref->parent) { | |
976b1908 | 903 | struct extent_inode_elem *eie = NULL; |
3301958b | 904 | if (extent_item_pos && !ref->inode_list) { |
976b1908 JS |
905 | u32 bsz; |
906 | struct extent_buffer *eb; | |
907 | bsz = btrfs_level_size(fs_info->extent_root, | |
908 | info_level); | |
909 | eb = read_tree_block(fs_info->extent_root, | |
910 | ref->parent, bsz, 0); | |
911 | BUG_ON(!eb); | |
912 | ret = find_extent_in_eb(eb, bytenr, | |
913 | *extent_item_pos, &eie); | |
3301958b | 914 | ref->inode_list = eie; |
976b1908 JS |
915 | free_extent_buffer(eb); |
916 | } | |
3301958b | 917 | ret = ulist_add_merge(refs, ref->parent, |
995e01b7 | 918 | (uintptr_t)ref->inode_list, |
34d73f54 | 919 | (u64 *)&eie, GFP_NOFS); |
3301958b JS |
920 | if (!ret && extent_item_pos) { |
921 | /* | |
922 | * we've recorded that parent, so we must extend | |
923 | * its inode list here | |
924 | */ | |
925 | BUG_ON(!eie); | |
926 | while (eie->next) | |
927 | eie = eie->next; | |
928 | eie->next = ref->inode_list; | |
929 | } | |
8da6d581 JS |
930 | BUG_ON(ret < 0); |
931 | } | |
932 | kfree(ref); | |
933 | } | |
934 | ||
935 | out: | |
8da6d581 JS |
936 | btrfs_free_path(path); |
937 | while (!list_empty(&prefs)) { | |
938 | ref = list_first_entry(&prefs, struct __prelim_ref, list); | |
939 | list_del(&ref->list); | |
940 | kfree(ref); | |
941 | } | |
942 | while (!list_empty(&prefs_delayed)) { | |
943 | ref = list_first_entry(&prefs_delayed, struct __prelim_ref, | |
944 | list); | |
945 | list_del(&ref->list); | |
946 | kfree(ref); | |
947 | } | |
948 | ||
949 | return ret; | |
950 | } | |
951 | ||
976b1908 JS |
952 | static void free_leaf_list(struct ulist *blocks) |
953 | { | |
954 | struct ulist_node *node = NULL; | |
955 | struct extent_inode_elem *eie; | |
956 | struct extent_inode_elem *eie_next; | |
957 | struct ulist_iterator uiter; | |
958 | ||
959 | ULIST_ITER_INIT(&uiter); | |
960 | while ((node = ulist_next(blocks, &uiter))) { | |
961 | if (!node->aux) | |
962 | continue; | |
995e01b7 | 963 | eie = (struct extent_inode_elem *)(uintptr_t)node->aux; |
976b1908 JS |
964 | for (; eie; eie = eie_next) { |
965 | eie_next = eie->next; | |
966 | kfree(eie); | |
967 | } | |
968 | node->aux = 0; | |
969 | } | |
970 | ||
971 | ulist_free(blocks); | |
972 | } | |
973 | ||
8da6d581 JS |
974 | /* |
975 | * Finds all leafs with a reference to the specified combination of bytenr and | |
976 | * offset. key_list_head will point to a list of corresponding keys (caller must | |
977 | * free each list element). The leafs will be stored in the leafs ulist, which | |
978 | * must be freed with ulist_free. | |
979 | * | |
980 | * returns 0 on success, <0 on error | |
981 | */ | |
982 | static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, | |
983 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
097b8a7c | 984 | u64 time_seq, struct ulist **leafs, |
976b1908 | 985 | const u64 *extent_item_pos) |
8da6d581 JS |
986 | { |
987 | struct ulist *tmp; | |
988 | int ret; | |
989 | ||
990 | tmp = ulist_alloc(GFP_NOFS); | |
991 | if (!tmp) | |
992 | return -ENOMEM; | |
993 | *leafs = ulist_alloc(GFP_NOFS); | |
994 | if (!*leafs) { | |
995 | ulist_free(tmp); | |
996 | return -ENOMEM; | |
997 | } | |
998 | ||
097b8a7c | 999 | ret = find_parent_nodes(trans, fs_info, bytenr, |
8445f61c | 1000 | time_seq, *leafs, tmp, extent_item_pos); |
8da6d581 JS |
1001 | ulist_free(tmp); |
1002 | ||
1003 | if (ret < 0 && ret != -ENOENT) { | |
976b1908 | 1004 | free_leaf_list(*leafs); |
8da6d581 JS |
1005 | return ret; |
1006 | } | |
1007 | ||
1008 | return 0; | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * walk all backrefs for a given extent to find all roots that reference this | |
1013 | * extent. Walking a backref means finding all extents that reference this | |
1014 | * extent and in turn walk the backrefs of those, too. Naturally this is a | |
1015 | * recursive process, but here it is implemented in an iterative fashion: We | |
1016 | * find all referencing extents for the extent in question and put them on a | |
1017 | * list. In turn, we find all referencing extents for those, further appending | |
1018 | * to the list. The way we iterate the list allows adding more elements after | |
1019 | * the current while iterating. The process stops when we reach the end of the | |
1020 | * list. Found roots are added to the roots list. | |
1021 | * | |
1022 | * returns 0 on success, < 0 on error. | |
1023 | */ | |
1024 | int btrfs_find_all_roots(struct btrfs_trans_handle *trans, | |
1025 | struct btrfs_fs_info *fs_info, u64 bytenr, | |
097b8a7c | 1026 | u64 time_seq, struct ulist **roots) |
8da6d581 JS |
1027 | { |
1028 | struct ulist *tmp; | |
1029 | struct ulist_node *node = NULL; | |
cd1b413c | 1030 | struct ulist_iterator uiter; |
8da6d581 JS |
1031 | int ret; |
1032 | ||
1033 | tmp = ulist_alloc(GFP_NOFS); | |
1034 | if (!tmp) | |
1035 | return -ENOMEM; | |
1036 | *roots = ulist_alloc(GFP_NOFS); | |
1037 | if (!*roots) { | |
1038 | ulist_free(tmp); | |
1039 | return -ENOMEM; | |
1040 | } | |
1041 | ||
cd1b413c | 1042 | ULIST_ITER_INIT(&uiter); |
8da6d581 | 1043 | while (1) { |
097b8a7c | 1044 | ret = find_parent_nodes(trans, fs_info, bytenr, |
8445f61c | 1045 | time_seq, tmp, *roots, NULL); |
8da6d581 JS |
1046 | if (ret < 0 && ret != -ENOENT) { |
1047 | ulist_free(tmp); | |
1048 | ulist_free(*roots); | |
1049 | return ret; | |
1050 | } | |
cd1b413c | 1051 | node = ulist_next(tmp, &uiter); |
8da6d581 JS |
1052 | if (!node) |
1053 | break; | |
1054 | bytenr = node->val; | |
1055 | } | |
1056 | ||
1057 | ulist_free(tmp); | |
1058 | return 0; | |
1059 | } | |
1060 | ||
1061 | ||
a542ad1b JS |
1062 | static int __inode_info(u64 inum, u64 ioff, u8 key_type, |
1063 | struct btrfs_root *fs_root, struct btrfs_path *path, | |
1064 | struct btrfs_key *found_key) | |
1065 | { | |
1066 | int ret; | |
1067 | struct btrfs_key key; | |
1068 | struct extent_buffer *eb; | |
1069 | ||
1070 | key.type = key_type; | |
1071 | key.objectid = inum; | |
1072 | key.offset = ioff; | |
1073 | ||
1074 | ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); | |
1075 | if (ret < 0) | |
1076 | return ret; | |
1077 | ||
1078 | eb = path->nodes[0]; | |
1079 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { | |
1080 | ret = btrfs_next_leaf(fs_root, path); | |
1081 | if (ret) | |
1082 | return ret; | |
1083 | eb = path->nodes[0]; | |
1084 | } | |
1085 | ||
1086 | btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); | |
1087 | if (found_key->type != key.type || found_key->objectid != key.objectid) | |
1088 | return 1; | |
1089 | ||
1090 | return 0; | |
1091 | } | |
1092 | ||
1093 | /* | |
1094 | * this makes the path point to (inum INODE_ITEM ioff) | |
1095 | */ | |
1096 | int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
1097 | struct btrfs_path *path) | |
1098 | { | |
1099 | struct btrfs_key key; | |
1100 | return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, | |
1101 | &key); | |
1102 | } | |
1103 | ||
1104 | static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, | |
1105 | struct btrfs_path *path, | |
1106 | struct btrfs_key *found_key) | |
1107 | { | |
1108 | return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, | |
1109 | found_key); | |
1110 | } | |
1111 | ||
f186373f MF |
1112 | int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, |
1113 | u64 start_off, struct btrfs_path *path, | |
1114 | struct btrfs_inode_extref **ret_extref, | |
1115 | u64 *found_off) | |
1116 | { | |
1117 | int ret, slot; | |
1118 | struct btrfs_key key; | |
1119 | struct btrfs_key found_key; | |
1120 | struct btrfs_inode_extref *extref; | |
1121 | struct extent_buffer *leaf; | |
1122 | unsigned long ptr; | |
1123 | ||
1124 | key.objectid = inode_objectid; | |
1125 | btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY); | |
1126 | key.offset = start_off; | |
1127 | ||
1128 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
1129 | if (ret < 0) | |
1130 | return ret; | |
1131 | ||
1132 | while (1) { | |
1133 | leaf = path->nodes[0]; | |
1134 | slot = path->slots[0]; | |
1135 | if (slot >= btrfs_header_nritems(leaf)) { | |
1136 | /* | |
1137 | * If the item at offset is not found, | |
1138 | * btrfs_search_slot will point us to the slot | |
1139 | * where it should be inserted. In our case | |
1140 | * that will be the slot directly before the | |
1141 | * next INODE_REF_KEY_V2 item. In the case | |
1142 | * that we're pointing to the last slot in a | |
1143 | * leaf, we must move one leaf over. | |
1144 | */ | |
1145 | ret = btrfs_next_leaf(root, path); | |
1146 | if (ret) { | |
1147 | if (ret >= 1) | |
1148 | ret = -ENOENT; | |
1149 | break; | |
1150 | } | |
1151 | continue; | |
1152 | } | |
1153 | ||
1154 | btrfs_item_key_to_cpu(leaf, &found_key, slot); | |
1155 | ||
1156 | /* | |
1157 | * Check that we're still looking at an extended ref key for | |
1158 | * this particular objectid. If we have different | |
1159 | * objectid or type then there are no more to be found | |
1160 | * in the tree and we can exit. | |
1161 | */ | |
1162 | ret = -ENOENT; | |
1163 | if (found_key.objectid != inode_objectid) | |
1164 | break; | |
1165 | if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY) | |
1166 | break; | |
1167 | ||
1168 | ret = 0; | |
1169 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); | |
1170 | extref = (struct btrfs_inode_extref *)ptr; | |
1171 | *ret_extref = extref; | |
1172 | if (found_off) | |
1173 | *found_off = found_key.offset; | |
1174 | break; | |
1175 | } | |
1176 | ||
1177 | return ret; | |
1178 | } | |
1179 | ||
d24bec3a MF |
1180 | static char *ref_to_path(struct btrfs_root *fs_root, |
1181 | struct btrfs_path *path, | |
1182 | u32 name_len, unsigned long name_off, | |
91cb916c AB |
1183 | struct extent_buffer *eb_in, u64 parent, |
1184 | char *dest, u32 size) | |
a542ad1b | 1185 | { |
a542ad1b JS |
1186 | int slot; |
1187 | u64 next_inum; | |
1188 | int ret; | |
1189 | s64 bytes_left = size - 1; | |
1190 | struct extent_buffer *eb = eb_in; | |
1191 | struct btrfs_key found_key; | |
b916a59a | 1192 | int leave_spinning = path->leave_spinning; |
d24bec3a | 1193 | struct btrfs_inode_ref *iref; |
a542ad1b JS |
1194 | |
1195 | if (bytes_left >= 0) | |
1196 | dest[bytes_left] = '\0'; | |
1197 | ||
b916a59a | 1198 | path->leave_spinning = 1; |
a542ad1b | 1199 | while (1) { |
d24bec3a | 1200 | bytes_left -= name_len; |
a542ad1b JS |
1201 | if (bytes_left >= 0) |
1202 | read_extent_buffer(eb, dest + bytes_left, | |
d24bec3a | 1203 | name_off, name_len); |
b916a59a JS |
1204 | if (eb != eb_in) { |
1205 | btrfs_tree_read_unlock_blocking(eb); | |
a542ad1b | 1206 | free_extent_buffer(eb); |
b916a59a | 1207 | } |
a542ad1b | 1208 | ret = inode_ref_info(parent, 0, fs_root, path, &found_key); |
8f24b496 JS |
1209 | if (ret > 0) |
1210 | ret = -ENOENT; | |
a542ad1b JS |
1211 | if (ret) |
1212 | break; | |
d24bec3a | 1213 | |
a542ad1b JS |
1214 | next_inum = found_key.offset; |
1215 | ||
1216 | /* regular exit ahead */ | |
1217 | if (parent == next_inum) | |
1218 | break; | |
1219 | ||
1220 | slot = path->slots[0]; | |
1221 | eb = path->nodes[0]; | |
1222 | /* make sure we can use eb after releasing the path */ | |
b916a59a | 1223 | if (eb != eb_in) { |
a542ad1b | 1224 | atomic_inc(&eb->refs); |
b916a59a JS |
1225 | btrfs_tree_read_lock(eb); |
1226 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
1227 | } | |
a542ad1b | 1228 | btrfs_release_path(path); |
a542ad1b | 1229 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); |
d24bec3a MF |
1230 | |
1231 | name_len = btrfs_inode_ref_name_len(eb, iref); | |
1232 | name_off = (unsigned long)(iref + 1); | |
1233 | ||
a542ad1b JS |
1234 | parent = next_inum; |
1235 | --bytes_left; | |
1236 | if (bytes_left >= 0) | |
1237 | dest[bytes_left] = '/'; | |
1238 | } | |
1239 | ||
1240 | btrfs_release_path(path); | |
b916a59a | 1241 | path->leave_spinning = leave_spinning; |
a542ad1b JS |
1242 | |
1243 | if (ret) | |
1244 | return ERR_PTR(ret); | |
1245 | ||
1246 | return dest + bytes_left; | |
1247 | } | |
1248 | ||
d24bec3a MF |
1249 | /* |
1250 | * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements | |
1251 | * of the path are separated by '/' and the path is guaranteed to be | |
1252 | * 0-terminated. the path is only given within the current file system. | |
1253 | * Therefore, it never starts with a '/'. the caller is responsible to provide | |
1254 | * "size" bytes in "dest". the dest buffer will be filled backwards. finally, | |
1255 | * the start point of the resulting string is returned. this pointer is within | |
1256 | * dest, normally. | |
1257 | * in case the path buffer would overflow, the pointer is decremented further | |
1258 | * as if output was written to the buffer, though no more output is actually | |
1259 | * generated. that way, the caller can determine how much space would be | |
1260 | * required for the path to fit into the buffer. in that case, the returned | |
1261 | * value will be smaller than dest. callers must check this! | |
1262 | */ | |
1263 | char *btrfs_iref_to_path(struct btrfs_root *fs_root, | |
1264 | struct btrfs_path *path, | |
1265 | struct btrfs_inode_ref *iref, | |
1266 | struct extent_buffer *eb_in, u64 parent, | |
1267 | char *dest, u32 size) | |
1268 | { | |
1269 | return ref_to_path(fs_root, path, | |
1270 | btrfs_inode_ref_name_len(eb_in, iref), | |
1271 | (unsigned long)(iref + 1), | |
1272 | eb_in, parent, dest, size); | |
1273 | } | |
1274 | ||
a542ad1b JS |
1275 | /* |
1276 | * this makes the path point to (logical EXTENT_ITEM *) | |
1277 | * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for | |
1278 | * tree blocks and <0 on error. | |
1279 | */ | |
1280 | int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, | |
69917e43 LB |
1281 | struct btrfs_path *path, struct btrfs_key *found_key, |
1282 | u64 *flags_ret) | |
a542ad1b JS |
1283 | { |
1284 | int ret; | |
1285 | u64 flags; | |
1286 | u32 item_size; | |
1287 | struct extent_buffer *eb; | |
1288 | struct btrfs_extent_item *ei; | |
1289 | struct btrfs_key key; | |
1290 | ||
1291 | key.type = BTRFS_EXTENT_ITEM_KEY; | |
1292 | key.objectid = logical; | |
1293 | key.offset = (u64)-1; | |
1294 | ||
1295 | ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); | |
1296 | if (ret < 0) | |
1297 | return ret; | |
1298 | ret = btrfs_previous_item(fs_info->extent_root, path, | |
1299 | 0, BTRFS_EXTENT_ITEM_KEY); | |
1300 | if (ret < 0) | |
1301 | return ret; | |
1302 | ||
1303 | btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); | |
1304 | if (found_key->type != BTRFS_EXTENT_ITEM_KEY || | |
1305 | found_key->objectid > logical || | |
4692cf58 JS |
1306 | found_key->objectid + found_key->offset <= logical) { |
1307 | pr_debug("logical %llu is not within any extent\n", | |
1308 | (unsigned long long)logical); | |
a542ad1b | 1309 | return -ENOENT; |
4692cf58 | 1310 | } |
a542ad1b JS |
1311 | |
1312 | eb = path->nodes[0]; | |
1313 | item_size = btrfs_item_size_nr(eb, path->slots[0]); | |
1314 | BUG_ON(item_size < sizeof(*ei)); | |
1315 | ||
1316 | ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); | |
1317 | flags = btrfs_extent_flags(eb, ei); | |
1318 | ||
4692cf58 JS |
1319 | pr_debug("logical %llu is at position %llu within the extent (%llu " |
1320 | "EXTENT_ITEM %llu) flags %#llx size %u\n", | |
1321 | (unsigned long long)logical, | |
1322 | (unsigned long long)(logical - found_key->objectid), | |
1323 | (unsigned long long)found_key->objectid, | |
1324 | (unsigned long long)found_key->offset, | |
1325 | (unsigned long long)flags, item_size); | |
69917e43 LB |
1326 | |
1327 | WARN_ON(!flags_ret); | |
1328 | if (flags_ret) { | |
1329 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) | |
1330 | *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK; | |
1331 | else if (flags & BTRFS_EXTENT_FLAG_DATA) | |
1332 | *flags_ret = BTRFS_EXTENT_FLAG_DATA; | |
1333 | else | |
1334 | BUG_ON(1); | |
1335 | return 0; | |
1336 | } | |
a542ad1b JS |
1337 | |
1338 | return -EIO; | |
1339 | } | |
1340 | ||
1341 | /* | |
1342 | * helper function to iterate extent inline refs. ptr must point to a 0 value | |
1343 | * for the first call and may be modified. it is used to track state. | |
1344 | * if more refs exist, 0 is returned and the next call to | |
1345 | * __get_extent_inline_ref must pass the modified ptr parameter to get the | |
1346 | * next ref. after the last ref was processed, 1 is returned. | |
1347 | * returns <0 on error | |
1348 | */ | |
1349 | static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, | |
1350 | struct btrfs_extent_item *ei, u32 item_size, | |
1351 | struct btrfs_extent_inline_ref **out_eiref, | |
1352 | int *out_type) | |
1353 | { | |
1354 | unsigned long end; | |
1355 | u64 flags; | |
1356 | struct btrfs_tree_block_info *info; | |
1357 | ||
1358 | if (!*ptr) { | |
1359 | /* first call */ | |
1360 | flags = btrfs_extent_flags(eb, ei); | |
1361 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { | |
1362 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1363 | *out_eiref = | |
1364 | (struct btrfs_extent_inline_ref *)(info + 1); | |
1365 | } else { | |
1366 | *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); | |
1367 | } | |
1368 | *ptr = (unsigned long)*out_eiref; | |
1369 | if ((void *)*ptr >= (void *)ei + item_size) | |
1370 | return -ENOENT; | |
1371 | } | |
1372 | ||
1373 | end = (unsigned long)ei + item_size; | |
1374 | *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; | |
1375 | *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); | |
1376 | ||
1377 | *ptr += btrfs_extent_inline_ref_size(*out_type); | |
1378 | WARN_ON(*ptr > end); | |
1379 | if (*ptr == end) | |
1380 | return 1; /* last */ | |
1381 | ||
1382 | return 0; | |
1383 | } | |
1384 | ||
1385 | /* | |
1386 | * reads the tree block backref for an extent. tree level and root are returned | |
1387 | * through out_level and out_root. ptr must point to a 0 value for the first | |
1388 | * call and may be modified (see __get_extent_inline_ref comment). | |
1389 | * returns 0 if data was provided, 1 if there was no more data to provide or | |
1390 | * <0 on error. | |
1391 | */ | |
1392 | int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, | |
1393 | struct btrfs_extent_item *ei, u32 item_size, | |
1394 | u64 *out_root, u8 *out_level) | |
1395 | { | |
1396 | int ret; | |
1397 | int type; | |
1398 | struct btrfs_tree_block_info *info; | |
1399 | struct btrfs_extent_inline_ref *eiref; | |
1400 | ||
1401 | if (*ptr == (unsigned long)-1) | |
1402 | return 1; | |
1403 | ||
1404 | while (1) { | |
1405 | ret = __get_extent_inline_ref(ptr, eb, ei, item_size, | |
1406 | &eiref, &type); | |
1407 | if (ret < 0) | |
1408 | return ret; | |
1409 | ||
1410 | if (type == BTRFS_TREE_BLOCK_REF_KEY || | |
1411 | type == BTRFS_SHARED_BLOCK_REF_KEY) | |
1412 | break; | |
1413 | ||
1414 | if (ret == 1) | |
1415 | return 1; | |
1416 | } | |
1417 | ||
1418 | /* we can treat both ref types equally here */ | |
1419 | info = (struct btrfs_tree_block_info *)(ei + 1); | |
1420 | *out_root = btrfs_extent_inline_ref_offset(eb, eiref); | |
1421 | *out_level = btrfs_tree_block_level(eb, info); | |
1422 | ||
1423 | if (ret == 1) | |
1424 | *ptr = (unsigned long)-1; | |
1425 | ||
1426 | return 0; | |
1427 | } | |
1428 | ||
976b1908 JS |
1429 | static int iterate_leaf_refs(struct extent_inode_elem *inode_list, |
1430 | u64 root, u64 extent_item_objectid, | |
4692cf58 | 1431 | iterate_extent_inodes_t *iterate, void *ctx) |
a542ad1b | 1432 | { |
976b1908 | 1433 | struct extent_inode_elem *eie; |
4692cf58 | 1434 | int ret = 0; |
4692cf58 | 1435 | |
976b1908 | 1436 | for (eie = inode_list; eie; eie = eie->next) { |
4692cf58 | 1437 | pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " |
976b1908 JS |
1438 | "root %llu\n", extent_item_objectid, |
1439 | eie->inum, eie->offset, root); | |
1440 | ret = iterate(eie->inum, eie->offset, root, ctx); | |
4692cf58 | 1441 | if (ret) { |
976b1908 JS |
1442 | pr_debug("stopping iteration for %llu due to ret=%d\n", |
1443 | extent_item_objectid, ret); | |
4692cf58 JS |
1444 | break; |
1445 | } | |
a542ad1b JS |
1446 | } |
1447 | ||
a542ad1b JS |
1448 | return ret; |
1449 | } | |
1450 | ||
1451 | /* | |
1452 | * calls iterate() for every inode that references the extent identified by | |
4692cf58 | 1453 | * the given parameters. |
a542ad1b JS |
1454 | * when the iterator function returns a non-zero value, iteration stops. |
1455 | */ | |
1456 | int iterate_extent_inodes(struct btrfs_fs_info *fs_info, | |
4692cf58 | 1457 | u64 extent_item_objectid, u64 extent_item_pos, |
7a3ae2f8 | 1458 | int search_commit_root, |
a542ad1b JS |
1459 | iterate_extent_inodes_t *iterate, void *ctx) |
1460 | { | |
a542ad1b | 1461 | int ret; |
a542ad1b JS |
1462 | struct list_head data_refs = LIST_HEAD_INIT(data_refs); |
1463 | struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); | |
4692cf58 | 1464 | struct btrfs_trans_handle *trans; |
7a3ae2f8 JS |
1465 | struct ulist *refs = NULL; |
1466 | struct ulist *roots = NULL; | |
4692cf58 JS |
1467 | struct ulist_node *ref_node = NULL; |
1468 | struct ulist_node *root_node = NULL; | |
8445f61c | 1469 | struct seq_list tree_mod_seq_elem = {}; |
cd1b413c JS |
1470 | struct ulist_iterator ref_uiter; |
1471 | struct ulist_iterator root_uiter; | |
a542ad1b | 1472 | |
4692cf58 JS |
1473 | pr_debug("resolving all inodes for extent %llu\n", |
1474 | extent_item_objectid); | |
a542ad1b | 1475 | |
7a3ae2f8 JS |
1476 | if (search_commit_root) { |
1477 | trans = BTRFS_BACKREF_SEARCH_COMMIT_ROOT; | |
1478 | } else { | |
1479 | trans = btrfs_join_transaction(fs_info->extent_root); | |
1480 | if (IS_ERR(trans)) | |
1481 | return PTR_ERR(trans); | |
8445f61c | 1482 | btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
7a3ae2f8 | 1483 | } |
a542ad1b | 1484 | |
4692cf58 | 1485 | ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
097b8a7c | 1486 | tree_mod_seq_elem.seq, &refs, |
8445f61c | 1487 | &extent_item_pos); |
4692cf58 JS |
1488 | if (ret) |
1489 | goto out; | |
a542ad1b | 1490 | |
cd1b413c JS |
1491 | ULIST_ITER_INIT(&ref_uiter); |
1492 | while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { | |
976b1908 | 1493 | ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, |
097b8a7c | 1494 | tree_mod_seq_elem.seq, &roots); |
4692cf58 JS |
1495 | if (ret) |
1496 | break; | |
cd1b413c JS |
1497 | ULIST_ITER_INIT(&root_uiter); |
1498 | while (!ret && (root_node = ulist_next(roots, &root_uiter))) { | |
976b1908 | 1499 | pr_debug("root %llu references leaf %llu, data list " |
34d73f54 | 1500 | "%#llx\n", root_node->val, ref_node->val, |
995e01b7 JS |
1501 | (long long)ref_node->aux); |
1502 | ret = iterate_leaf_refs((struct extent_inode_elem *) | |
1503 | (uintptr_t)ref_node->aux, | |
1504 | root_node->val, | |
1505 | extent_item_objectid, | |
1506 | iterate, ctx); | |
4692cf58 | 1507 | } |
976b1908 JS |
1508 | ulist_free(roots); |
1509 | roots = NULL; | |
a542ad1b JS |
1510 | } |
1511 | ||
976b1908 | 1512 | free_leaf_list(refs); |
4692cf58 JS |
1513 | ulist_free(roots); |
1514 | out: | |
7a3ae2f8 | 1515 | if (!search_commit_root) { |
8445f61c | 1516 | btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
7a3ae2f8 JS |
1517 | btrfs_end_transaction(trans, fs_info->extent_root); |
1518 | } | |
1519 | ||
a542ad1b JS |
1520 | return ret; |
1521 | } | |
1522 | ||
1523 | int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, | |
1524 | struct btrfs_path *path, | |
1525 | iterate_extent_inodes_t *iterate, void *ctx) | |
1526 | { | |
1527 | int ret; | |
4692cf58 | 1528 | u64 extent_item_pos; |
69917e43 | 1529 | u64 flags = 0; |
a542ad1b | 1530 | struct btrfs_key found_key; |
7a3ae2f8 | 1531 | int search_commit_root = path->search_commit_root; |
a542ad1b | 1532 | |
69917e43 | 1533 | ret = extent_from_logical(fs_info, logical, path, &found_key, &flags); |
4692cf58 | 1534 | btrfs_release_path(path); |
a542ad1b JS |
1535 | if (ret < 0) |
1536 | return ret; | |
69917e43 | 1537 | if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
3627bf45 | 1538 | return -EINVAL; |
a542ad1b | 1539 | |
4692cf58 | 1540 | extent_item_pos = logical - found_key.objectid; |
7a3ae2f8 JS |
1541 | ret = iterate_extent_inodes(fs_info, found_key.objectid, |
1542 | extent_item_pos, search_commit_root, | |
1543 | iterate, ctx); | |
a542ad1b JS |
1544 | |
1545 | return ret; | |
1546 | } | |
1547 | ||
d24bec3a MF |
1548 | typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off, |
1549 | struct extent_buffer *eb, void *ctx); | |
1550 | ||
1551 | static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, | |
1552 | struct btrfs_path *path, | |
1553 | iterate_irefs_t *iterate, void *ctx) | |
a542ad1b | 1554 | { |
aefc1eb1 | 1555 | int ret = 0; |
a542ad1b JS |
1556 | int slot; |
1557 | u32 cur; | |
1558 | u32 len; | |
1559 | u32 name_len; | |
1560 | u64 parent = 0; | |
1561 | int found = 0; | |
1562 | struct extent_buffer *eb; | |
1563 | struct btrfs_item *item; | |
1564 | struct btrfs_inode_ref *iref; | |
1565 | struct btrfs_key found_key; | |
1566 | ||
aefc1eb1 | 1567 | while (!ret) { |
b916a59a | 1568 | path->leave_spinning = 1; |
a542ad1b | 1569 | ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, |
d24bec3a | 1570 | &found_key); |
a542ad1b JS |
1571 | if (ret < 0) |
1572 | break; | |
1573 | if (ret) { | |
1574 | ret = found ? 0 : -ENOENT; | |
1575 | break; | |
1576 | } | |
1577 | ++found; | |
1578 | ||
1579 | parent = found_key.offset; | |
1580 | slot = path->slots[0]; | |
1581 | eb = path->nodes[0]; | |
1582 | /* make sure we can use eb after releasing the path */ | |
1583 | atomic_inc(&eb->refs); | |
b916a59a JS |
1584 | btrfs_tree_read_lock(eb); |
1585 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
a542ad1b JS |
1586 | btrfs_release_path(path); |
1587 | ||
1588 | item = btrfs_item_nr(eb, slot); | |
1589 | iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); | |
1590 | ||
1591 | for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { | |
1592 | name_len = btrfs_inode_ref_name_len(eb, iref); | |
1593 | /* path must be released before calling iterate()! */ | |
4692cf58 JS |
1594 | pr_debug("following ref at offset %u for inode %llu in " |
1595 | "tree %llu\n", cur, | |
1596 | (unsigned long long)found_key.objectid, | |
1597 | (unsigned long long)fs_root->objectid); | |
d24bec3a MF |
1598 | ret = iterate(parent, name_len, |
1599 | (unsigned long)(iref + 1), eb, ctx); | |
aefc1eb1 | 1600 | if (ret) |
a542ad1b | 1601 | break; |
a542ad1b JS |
1602 | len = sizeof(*iref) + name_len; |
1603 | iref = (struct btrfs_inode_ref *)((char *)iref + len); | |
1604 | } | |
b916a59a | 1605 | btrfs_tree_read_unlock_blocking(eb); |
a542ad1b JS |
1606 | free_extent_buffer(eb); |
1607 | } | |
1608 | ||
1609 | btrfs_release_path(path); | |
1610 | ||
1611 | return ret; | |
1612 | } | |
1613 | ||
d24bec3a MF |
1614 | static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, |
1615 | struct btrfs_path *path, | |
1616 | iterate_irefs_t *iterate, void *ctx) | |
1617 | { | |
1618 | int ret; | |
1619 | int slot; | |
1620 | u64 offset = 0; | |
1621 | u64 parent; | |
1622 | int found = 0; | |
1623 | struct extent_buffer *eb; | |
1624 | struct btrfs_inode_extref *extref; | |
1625 | struct extent_buffer *leaf; | |
1626 | u32 item_size; | |
1627 | u32 cur_offset; | |
1628 | unsigned long ptr; | |
1629 | ||
1630 | while (1) { | |
1631 | ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref, | |
1632 | &offset); | |
1633 | if (ret < 0) | |
1634 | break; | |
1635 | if (ret) { | |
1636 | ret = found ? 0 : -ENOENT; | |
1637 | break; | |
1638 | } | |
1639 | ++found; | |
1640 | ||
1641 | slot = path->slots[0]; | |
1642 | eb = path->nodes[0]; | |
1643 | /* make sure we can use eb after releasing the path */ | |
1644 | atomic_inc(&eb->refs); | |
1645 | ||
1646 | btrfs_tree_read_lock(eb); | |
1647 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
1648 | btrfs_release_path(path); | |
1649 | ||
1650 | leaf = path->nodes[0]; | |
1651 | item_size = btrfs_item_size_nr(leaf, path->slots[0]); | |
1652 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); | |
1653 | cur_offset = 0; | |
1654 | ||
1655 | while (cur_offset < item_size) { | |
1656 | u32 name_len; | |
1657 | ||
1658 | extref = (struct btrfs_inode_extref *)(ptr + cur_offset); | |
1659 | parent = btrfs_inode_extref_parent(eb, extref); | |
1660 | name_len = btrfs_inode_extref_name_len(eb, extref); | |
1661 | ret = iterate(parent, name_len, | |
1662 | (unsigned long)&extref->name, eb, ctx); | |
1663 | if (ret) | |
1664 | break; | |
1665 | ||
1666 | cur_offset += btrfs_inode_extref_name_len(leaf, extref); | |
1667 | cur_offset += sizeof(*extref); | |
1668 | } | |
1669 | btrfs_tree_read_unlock_blocking(eb); | |
1670 | free_extent_buffer(eb); | |
1671 | ||
1672 | offset++; | |
1673 | } | |
1674 | ||
1675 | btrfs_release_path(path); | |
1676 | ||
1677 | return ret; | |
1678 | } | |
1679 | ||
1680 | static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, | |
1681 | struct btrfs_path *path, iterate_irefs_t *iterate, | |
1682 | void *ctx) | |
1683 | { | |
1684 | int ret; | |
1685 | int found_refs = 0; | |
1686 | ||
1687 | ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx); | |
1688 | if (!ret) | |
1689 | ++found_refs; | |
1690 | else if (ret != -ENOENT) | |
1691 | return ret; | |
1692 | ||
1693 | ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx); | |
1694 | if (ret == -ENOENT && found_refs) | |
1695 | return 0; | |
1696 | ||
1697 | return ret; | |
1698 | } | |
1699 | ||
a542ad1b JS |
1700 | /* |
1701 | * returns 0 if the path could be dumped (probably truncated) | |
1702 | * returns <0 in case of an error | |
1703 | */ | |
d24bec3a MF |
1704 | static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, |
1705 | struct extent_buffer *eb, void *ctx) | |
a542ad1b JS |
1706 | { |
1707 | struct inode_fs_paths *ipath = ctx; | |
1708 | char *fspath; | |
1709 | char *fspath_min; | |
1710 | int i = ipath->fspath->elem_cnt; | |
1711 | const int s_ptr = sizeof(char *); | |
1712 | u32 bytes_left; | |
1713 | ||
1714 | bytes_left = ipath->fspath->bytes_left > s_ptr ? | |
1715 | ipath->fspath->bytes_left - s_ptr : 0; | |
1716 | ||
740c3d22 | 1717 | fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
d24bec3a MF |
1718 | fspath = ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len, |
1719 | name_off, eb, inum, fspath_min, | |
1720 | bytes_left); | |
a542ad1b JS |
1721 | if (IS_ERR(fspath)) |
1722 | return PTR_ERR(fspath); | |
1723 | ||
1724 | if (fspath > fspath_min) { | |
745c4d8e | 1725 | ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
a542ad1b JS |
1726 | ++ipath->fspath->elem_cnt; |
1727 | ipath->fspath->bytes_left = fspath - fspath_min; | |
1728 | } else { | |
1729 | ++ipath->fspath->elem_missed; | |
1730 | ipath->fspath->bytes_missing += fspath_min - fspath; | |
1731 | ipath->fspath->bytes_left = 0; | |
1732 | } | |
1733 | ||
1734 | return 0; | |
1735 | } | |
1736 | ||
1737 | /* | |
1738 | * this dumps all file system paths to the inode into the ipath struct, provided | |
1739 | * is has been created large enough. each path is zero-terminated and accessed | |
740c3d22 | 1740 | * from ipath->fspath->val[i]. |
a542ad1b | 1741 | * when it returns, there are ipath->fspath->elem_cnt number of paths available |
740c3d22 | 1742 | * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
a542ad1b JS |
1743 | * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, |
1744 | * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would | |
1745 | * have been needed to return all paths. | |
1746 | */ | |
1747 | int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) | |
1748 | { | |
1749 | return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, | |
d24bec3a | 1750 | inode_to_path, ipath); |
a542ad1b JS |
1751 | } |
1752 | ||
a542ad1b JS |
1753 | struct btrfs_data_container *init_data_container(u32 total_bytes) |
1754 | { | |
1755 | struct btrfs_data_container *data; | |
1756 | size_t alloc_bytes; | |
1757 | ||
1758 | alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); | |
425d17a2 | 1759 | data = vmalloc(alloc_bytes); |
a542ad1b JS |
1760 | if (!data) |
1761 | return ERR_PTR(-ENOMEM); | |
1762 | ||
1763 | if (total_bytes >= sizeof(*data)) { | |
1764 | data->bytes_left = total_bytes - sizeof(*data); | |
1765 | data->bytes_missing = 0; | |
1766 | } else { | |
1767 | data->bytes_missing = sizeof(*data) - total_bytes; | |
1768 | data->bytes_left = 0; | |
1769 | } | |
1770 | ||
1771 | data->elem_cnt = 0; | |
1772 | data->elem_missed = 0; | |
1773 | ||
1774 | return data; | |
1775 | } | |
1776 | ||
1777 | /* | |
1778 | * allocates space to return multiple file system paths for an inode. | |
1779 | * total_bytes to allocate are passed, note that space usable for actual path | |
1780 | * information will be total_bytes - sizeof(struct inode_fs_paths). | |
1781 | * the returned pointer must be freed with free_ipath() in the end. | |
1782 | */ | |
1783 | struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, | |
1784 | struct btrfs_path *path) | |
1785 | { | |
1786 | struct inode_fs_paths *ifp; | |
1787 | struct btrfs_data_container *fspath; | |
1788 | ||
1789 | fspath = init_data_container(total_bytes); | |
1790 | if (IS_ERR(fspath)) | |
1791 | return (void *)fspath; | |
1792 | ||
1793 | ifp = kmalloc(sizeof(*ifp), GFP_NOFS); | |
1794 | if (!ifp) { | |
1795 | kfree(fspath); | |
1796 | return ERR_PTR(-ENOMEM); | |
1797 | } | |
1798 | ||
1799 | ifp->btrfs_path = path; | |
1800 | ifp->fspath = fspath; | |
1801 | ifp->fs_root = fs_root; | |
1802 | ||
1803 | return ifp; | |
1804 | } | |
1805 | ||
1806 | void free_ipath(struct inode_fs_paths *ipath) | |
1807 | { | |
4735fb28 JJ |
1808 | if (!ipath) |
1809 | return; | |
425d17a2 | 1810 | vfree(ipath->fspath); |
a542ad1b JS |
1811 | kfree(ipath); |
1812 | } |