blob: 455a6b2fd53957709ecfdf9aeff5386a4e60e2d0 [file] [log] [blame]
Jan Schmidta542ad12011-06-13 19:52:59 +02001/*
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
Liu Bo425d17a2012-09-07 20:01:30 -060019#include <linux/vmalloc.h>
Jan Schmidta542ad12011-06-13 19:52:59 +020020#include "ctree.h"
21#include "disk-io.h"
22#include "backref.h"
Jan Schmidt8da6d582011-11-23 18:55:04 +010023#include "ulist.h"
24#include "transaction.h"
25#include "delayed-ref.h"
Jan Schmidtb916a592012-04-13 12:28:08 +020026#include "locking.h"
Jan Schmidta542ad12011-06-13 19:52:59 +020027
Josef Bacikdc046b12014-09-10 16:20:45 -040028/* Just an arbitrary number so we can be sure this happened */
29#define BACKREF_FOUND_SHARED 6
30
Jan Schmidt976b1902012-05-17 16:43:03 +020031struct extent_inode_elem {
32 u64 inum;
33 u64 offset;
34 struct extent_inode_elem *next;
35};
36
37static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
38 struct btrfs_file_extent_item *fi,
39 u64 extent_item_pos,
40 struct extent_inode_elem **eie)
41{
Josef Bacik8ca15e02013-07-05 13:58:19 -040042 u64 offset = 0;
Jan Schmidt976b1902012-05-17 16:43:03 +020043 struct extent_inode_elem *e;
44
Josef Bacik8ca15e02013-07-05 13:58:19 -040045 if (!btrfs_file_extent_compression(eb, fi) &&
46 !btrfs_file_extent_encryption(eb, fi) &&
47 !btrfs_file_extent_other_encoding(eb, fi)) {
48 u64 data_offset;
49 u64 data_len;
Jan Schmidt976b1902012-05-17 16:43:03 +020050
Josef Bacik8ca15e02013-07-05 13:58:19 -040051 data_offset = btrfs_file_extent_offset(eb, fi);
52 data_len = btrfs_file_extent_num_bytes(eb, fi);
53
54 if (extent_item_pos < data_offset ||
55 extent_item_pos >= data_offset + data_len)
56 return 1;
57 offset = extent_item_pos - data_offset;
58 }
Jan Schmidt976b1902012-05-17 16:43:03 +020059
60 e = kmalloc(sizeof(*e), GFP_NOFS);
61 if (!e)
62 return -ENOMEM;
63
64 e->next = *eie;
65 e->inum = key->objectid;
Josef Bacik8ca15e02013-07-05 13:58:19 -040066 e->offset = key->offset + offset;
Jan Schmidt976b1902012-05-17 16:43:03 +020067 *eie = e;
68
69 return 0;
70}
71
Wang Shilongf05c4742014-01-28 19:13:38 +080072static void free_inode_elem_list(struct extent_inode_elem *eie)
73{
74 struct extent_inode_elem *eie_next;
75
76 for (; eie; eie = eie_next) {
77 eie_next = eie->next;
78 kfree(eie);
79 }
80}
81
Jan Schmidt976b1902012-05-17 16:43:03 +020082static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
83 u64 extent_item_pos,
84 struct extent_inode_elem **eie)
85{
86 u64 disk_byte;
87 struct btrfs_key key;
88 struct btrfs_file_extent_item *fi;
89 int slot;
90 int nritems;
91 int extent_type;
92 int ret;
93
94 /*
95 * from the shared data ref, we only have the leaf but we need
96 * the key. thus, we must look into all items and see that we
97 * find one (some) with a reference to our extent item.
98 */
99 nritems = btrfs_header_nritems(eb);
100 for (slot = 0; slot < nritems; ++slot) {
101 btrfs_item_key_to_cpu(eb, &key, slot);
102 if (key.type != BTRFS_EXTENT_DATA_KEY)
103 continue;
104 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
105 extent_type = btrfs_file_extent_type(eb, fi);
106 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
107 continue;
108 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
109 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
110 if (disk_byte != wanted_disk_byte)
111 continue;
112
113 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
114 if (ret < 0)
115 return ret;
116 }
117
118 return 0;
119}
120
Jan Schmidt8da6d582011-11-23 18:55:04 +0100121/*
122 * this structure records all encountered refs on the way up to the root
123 */
124struct __prelim_ref {
125 struct list_head list;
126 u64 root_id;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200127 struct btrfs_key key_for_search;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100128 int level;
129 int count;
Jan Schmidt33019582012-05-30 18:05:21 +0200130 struct extent_inode_elem *inode_list;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100131 u64 parent;
132 u64 wanted_disk_byte;
133};
134
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800135static struct kmem_cache *btrfs_prelim_ref_cache;
136
137int __init btrfs_prelim_ref_init(void)
138{
139 btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
140 sizeof(struct __prelim_ref),
141 0,
Nikolay Borisovfba4b692016-06-23 21:17:08 +0300142 SLAB_MEM_SPREAD,
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800143 NULL);
144 if (!btrfs_prelim_ref_cache)
145 return -ENOMEM;
146 return 0;
147}
148
149void btrfs_prelim_ref_exit(void)
150{
Kinglong Mee5598e902016-01-29 21:36:35 +0800151 kmem_cache_destroy(btrfs_prelim_ref_cache);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800152}
153
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200154/*
155 * the rules for all callers of this function are:
156 * - obtaining the parent is the goal
157 * - if you add a key, you must know that it is a correct key
158 * - if you cannot add the parent or a correct key, then we will look into the
159 * block later to set a correct key
160 *
161 * delayed refs
162 * ============
163 * backref type | shared | indirect | shared | indirect
164 * information | tree | tree | data | data
165 * --------------------+--------+----------+--------+----------
166 * parent logical | y | - | - | -
167 * key to resolve | - | y | y | y
168 * tree block logical | - | - | - | -
169 * root for resolving | y | y | y | y
170 *
171 * - column 1: we've the parent -> done
172 * - column 2, 3, 4: we use the key to find the parent
173 *
174 * on disk refs (inline or keyed)
175 * ==============================
176 * backref type | shared | indirect | shared | indirect
177 * information | tree | tree | data | data
178 * --------------------+--------+----------+--------+----------
179 * parent logical | y | - | y | -
180 * key to resolve | - | - | - | y
181 * tree block logical | y | y | y | y
182 * root for resolving | - | y | y | y
183 *
184 * - column 1, 3: we've the parent -> done
185 * - column 2: we take the first key from the block to find the parent
186 * (see __add_missing_keys)
187 * - column 4: we use the key to find the parent
188 *
189 * additional information that's available but not required to find the parent
190 * block might help in merging entries to gain some speed.
191 */
192
Jan Schmidt8da6d582011-11-23 18:55:04 +0100193static int __add_prelim_ref(struct list_head *head, u64 root_id,
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200194 struct btrfs_key *key, int level,
Wang Shilong742916b2013-08-06 10:29:54 +0800195 u64 parent, u64 wanted_disk_byte, int count,
196 gfp_t gfp_mask)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100197{
198 struct __prelim_ref *ref;
199
Liu Bo48ec4732013-10-30 13:25:24 +0800200 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
201 return 0;
202
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800203 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100204 if (!ref)
205 return -ENOMEM;
206
207 ref->root_id = root_id;
Filipe Mananad6589102015-07-29 17:21:17 +0100208 if (key) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200209 ref->key_for_search = *key;
Filipe Mananad6589102015-07-29 17:21:17 +0100210 /*
211 * We can often find data backrefs with an offset that is too
212 * large (>= LLONG_MAX, maximum allowed file offset) due to
213 * underflows when subtracting a file's offset with the data
214 * offset of its corresponding extent data item. This can
215 * happen for example in the clone ioctl.
216 * So if we detect such case we set the search key's offset to
217 * zero to make sure we will find the matching file extent item
218 * at add_all_parents(), otherwise we will miss it because the
219 * offset taken form the backref is much larger then the offset
220 * of the file extent item. This can make us scan a very large
221 * number of file extent items, but at least it will not make
222 * us miss any.
223 * This is an ugly workaround for a behaviour that should have
224 * never existed, but it does and a fix for the clone ioctl
225 * would touch a lot of places, cause backwards incompatibility
226 * and would not fix the problem for extents cloned with older
227 * kernels.
228 */
229 if (ref->key_for_search.type == BTRFS_EXTENT_DATA_KEY &&
230 ref->key_for_search.offset >= LLONG_MAX)
231 ref->key_for_search.offset = 0;
232 } else {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200233 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
Filipe Mananad6589102015-07-29 17:21:17 +0100234 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100235
Jan Schmidt33019582012-05-30 18:05:21 +0200236 ref->inode_list = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100237 ref->level = level;
238 ref->count = count;
239 ref->parent = parent;
240 ref->wanted_disk_byte = wanted_disk_byte;
241 list_add_tail(&ref->list, head);
242
243 return 0;
244}
245
246static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500247 struct ulist *parents, struct __prelim_ref *ref,
Josef Bacik44853862014-03-19 13:35:14 -0400248 int level, u64 time_seq, const u64 *extent_item_pos,
249 u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100250{
Alexander Block69bca402012-06-19 07:42:26 -0600251 int ret = 0;
252 int slot;
253 struct extent_buffer *eb;
254 struct btrfs_key key;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500255 struct btrfs_key *key_for_search = &ref->key_for_search;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100256 struct btrfs_file_extent_item *fi;
Josef Baciked8c4912013-07-05 14:03:47 -0400257 struct extent_inode_elem *eie = NULL, *old = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100258 u64 disk_byte;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500259 u64 wanted_disk_byte = ref->wanted_disk_byte;
260 u64 count = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100261
Alexander Block69bca402012-06-19 07:42:26 -0600262 if (level != 0) {
263 eb = path->nodes[level];
264 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
Jan Schmidt33019582012-05-30 18:05:21 +0200265 if (ret < 0)
266 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100267 return 0;
Alexander Block69bca402012-06-19 07:42:26 -0600268 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100269
270 /*
Alexander Block69bca402012-06-19 07:42:26 -0600271 * We normally enter this function with the path already pointing to
272 * the first item to check. But sometimes, we may enter it with
273 * slot==nritems. In that case, go to the next leaf before we continue.
Jan Schmidt8da6d582011-11-23 18:55:04 +0100274 */
Qu Wenruo21633fc2015-04-16 14:54:50 +0800275 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
276 if (time_seq == (u64)-1)
277 ret = btrfs_next_leaf(root, path);
278 else
279 ret = btrfs_next_old_leaf(root, path, time_seq);
280 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100281
Josef Bacik44853862014-03-19 13:35:14 -0400282 while (!ret && count < total_refs) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100283 eb = path->nodes[0];
Alexander Block69bca402012-06-19 07:42:26 -0600284 slot = path->slots[0];
285
286 btrfs_item_key_to_cpu(eb, &key, slot);
287
288 if (key.objectid != key_for_search->objectid ||
289 key.type != BTRFS_EXTENT_DATA_KEY)
290 break;
291
292 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
293 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
294
295 if (disk_byte == wanted_disk_byte) {
296 eie = NULL;
Josef Baciked8c4912013-07-05 14:03:47 -0400297 old = NULL;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500298 count++;
Alexander Block69bca402012-06-19 07:42:26 -0600299 if (extent_item_pos) {
300 ret = check_extent_in_eb(&key, eb, fi,
301 *extent_item_pos,
302 &eie);
303 if (ret < 0)
304 break;
305 }
Josef Baciked8c4912013-07-05 14:03:47 -0400306 if (ret > 0)
307 goto next;
Takashi Iwai4eb1f662014-07-28 10:57:04 +0200308 ret = ulist_add_merge_ptr(parents, eb->start,
309 eie, (void **)&old, GFP_NOFS);
Josef Baciked8c4912013-07-05 14:03:47 -0400310 if (ret < 0)
311 break;
312 if (!ret && extent_item_pos) {
313 while (old->next)
314 old = old->next;
315 old->next = eie;
Alexander Block69bca402012-06-19 07:42:26 -0600316 }
Wang Shilongf05c4742014-01-28 19:13:38 +0800317 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100318 }
Josef Baciked8c4912013-07-05 14:03:47 -0400319next:
Qu Wenruo21633fc2015-04-16 14:54:50 +0800320 if (time_seq == (u64)-1)
321 ret = btrfs_next_item(root, path);
322 else
323 ret = btrfs_next_old_item(root, path, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100324 }
325
Alexander Block69bca402012-06-19 07:42:26 -0600326 if (ret > 0)
327 ret = 0;
Wang Shilongf05c4742014-01-28 19:13:38 +0800328 else if (ret < 0)
329 free_inode_elem_list(eie);
Alexander Block69bca402012-06-19 07:42:26 -0600330 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100331}
332
333/*
334 * resolve an indirect backref in the form (root_id, key, level)
335 * to a logical address
336 */
337static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400338 struct btrfs_path *path, u64 time_seq,
339 struct __prelim_ref *ref,
340 struct ulist *parents,
Josef Bacik44853862014-03-19 13:35:14 -0400341 const u64 *extent_item_pos, u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100342{
Jan Schmidt8da6d582011-11-23 18:55:04 +0100343 struct btrfs_root *root;
344 struct btrfs_key root_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100345 struct extent_buffer *eb;
346 int ret = 0;
347 int root_level;
348 int level = ref->level;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800349 int index;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100350
Jan Schmidt8da6d582011-11-23 18:55:04 +0100351 root_key.objectid = ref->root_id;
352 root_key.type = BTRFS_ROOT_ITEM_KEY;
353 root_key.offset = (u64)-1;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800354
355 index = srcu_read_lock(&fs_info->subvol_srcu);
356
Josef Bacik2d9e9772015-11-05 14:37:58 -0800357 root = btrfs_get_fs_root(fs_info, &root_key, false);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100358 if (IS_ERR(root)) {
Wang Shilong538f72cd2014-01-23 13:47:48 +0800359 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100360 ret = PTR_ERR(root);
361 goto out;
362 }
363
Jeff Mahoneyf5ee5c92016-06-21 09:52:41 -0400364 if (btrfs_is_testing(fs_info)) {
Josef Bacikd9ee5222015-10-05 10:35:29 -0400365 srcu_read_unlock(&fs_info->subvol_srcu, index);
366 ret = -ENOENT;
367 goto out;
368 }
369
Josef Bacik9e351cc2014-03-13 15:42:13 -0400370 if (path->search_commit_root)
371 root_level = btrfs_header_level(root->commit_root);
Qu Wenruo21633fc2015-04-16 14:54:50 +0800372 else if (time_seq == (u64)-1)
373 root_level = btrfs_header_level(root->node);
Josef Bacik9e351cc2014-03-13 15:42:13 -0400374 else
375 root_level = btrfs_old_root_level(root, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100376
Wang Shilong538f72cd2014-01-23 13:47:48 +0800377 if (root_level + 1 == level) {
378 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100379 goto out;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800380 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100381
382 path->lowest_level = level;
Qu Wenruo21633fc2015-04-16 14:54:50 +0800383 if (time_seq == (u64)-1)
384 ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
385 0, 0);
386 else
387 ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
388 time_seq);
Wang Shilong538f72cd2014-01-23 13:47:48 +0800389
390 /* root node has been locked, we can release @subvol_srcu safely here */
391 srcu_read_unlock(&fs_info->subvol_srcu, index);
392
Jan Schmidt8da6d582011-11-23 18:55:04 +0100393 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
394 "%d for key (%llu %u %llu)\n",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +0200395 ref->root_id, level, ref->count, ret,
396 ref->key_for_search.objectid, ref->key_for_search.type,
397 ref->key_for_search.offset);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100398 if (ret < 0)
399 goto out;
400
401 eb = path->nodes[level];
Jan Schmidt93454572012-06-27 15:23:09 +0200402 while (!eb) {
Dulshani Gunawardhanafae7f212013-10-31 10:30:08 +0530403 if (WARN_ON(!level)) {
Jan Schmidt93454572012-06-27 15:23:09 +0200404 ret = 1;
405 goto out;
406 }
407 level--;
408 eb = path->nodes[level];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100409 }
410
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500411 ret = add_all_parents(root, path, parents, ref, level, time_seq,
Josef Bacik44853862014-03-19 13:35:14 -0400412 extent_item_pos, total_refs);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100413out:
Josef Bacikda61d312013-06-12 16:20:08 -0400414 path->lowest_level = 0;
415 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100416 return ret;
417}
418
419/*
420 * resolve all indirect backrefs from the list
421 */
422static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400423 struct btrfs_path *path, u64 time_seq,
Jan Schmidt976b1902012-05-17 16:43:03 +0200424 struct list_head *head,
Josef Bacikdc046b12014-09-10 16:20:45 -0400425 const u64 *extent_item_pos, u64 total_refs,
426 u64 root_objectid)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100427{
428 int err;
429 int ret = 0;
430 struct __prelim_ref *ref;
431 struct __prelim_ref *ref_safe;
432 struct __prelim_ref *new_ref;
433 struct ulist *parents;
434 struct ulist_node *node;
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200435 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100436
437 parents = ulist_alloc(GFP_NOFS);
438 if (!parents)
439 return -ENOMEM;
440
441 /*
442 * _safe allows us to insert directly after the current item without
443 * iterating over the newly inserted items.
444 * we're also allowed to re-assign ref during iteration.
445 */
446 list_for_each_entry_safe(ref, ref_safe, head, list) {
447 if (ref->parent) /* already direct */
448 continue;
449 if (ref->count == 0)
450 continue;
Josef Bacikdc046b12014-09-10 16:20:45 -0400451 if (root_objectid && ref->root_id != root_objectid) {
452 ret = BACKREF_FOUND_SHARED;
453 goto out;
454 }
Josef Bacikda61d312013-06-12 16:20:08 -0400455 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
Josef Bacik44853862014-03-19 13:35:14 -0400456 parents, extent_item_pos,
457 total_refs);
Wang Shilong95def2ed2014-01-23 13:47:49 +0800458 /*
459 * we can only tolerate ENOENT,otherwise,we should catch error
460 * and return directly.
461 */
462 if (err == -ENOENT) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100463 continue;
Wang Shilong95def2ed2014-01-23 13:47:49 +0800464 } else if (err) {
465 ret = err;
466 goto out;
467 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100468
469 /* we put the first parent into the ref at hand */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200470 ULIST_ITER_INIT(&uiter);
471 node = ulist_next(parents, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100472 ref->parent = node ? node->val : 0;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600473 ref->inode_list = node ?
Stefan Behrens35a36212013-08-14 18:12:25 +0200474 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100475
476 /* additional parents require new refs being added here */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200477 while ((node = ulist_next(parents, &uiter))) {
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800478 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
479 GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100480 if (!new_ref) {
481 ret = -ENOMEM;
Wang Shilonge36902d2013-04-15 10:26:38 +0000482 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100483 }
484 memcpy(new_ref, ref, sizeof(*ref));
485 new_ref->parent = node->val;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600486 new_ref->inode_list = (struct extent_inode_elem *)
487 (uintptr_t)node->aux;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100488 list_add(&new_ref->list, &ref->list);
489 }
490 ulist_reinit(parents);
491 }
Wang Shilonge36902d2013-04-15 10:26:38 +0000492out:
Jan Schmidt8da6d582011-11-23 18:55:04 +0100493 ulist_free(parents);
494 return ret;
495}
496
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200497static inline int ref_for_same_block(struct __prelim_ref *ref1,
498 struct __prelim_ref *ref2)
499{
500 if (ref1->level != ref2->level)
501 return 0;
502 if (ref1->root_id != ref2->root_id)
503 return 0;
504 if (ref1->key_for_search.type != ref2->key_for_search.type)
505 return 0;
506 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
507 return 0;
508 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
509 return 0;
510 if (ref1->parent != ref2->parent)
511 return 0;
512
513 return 1;
514}
515
516/*
517 * read tree blocks and add keys where required.
518 */
519static int __add_missing_keys(struct btrfs_fs_info *fs_info,
520 struct list_head *head)
521{
Geliang Tanga7ca4222015-12-21 23:50:23 +0800522 struct __prelim_ref *ref;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200523 struct extent_buffer *eb;
524
Geliang Tanga7ca4222015-12-21 23:50:23 +0800525 list_for_each_entry(ref, head, list) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200526 if (ref->parent)
527 continue;
528 if (ref->key_for_search.type)
529 continue;
530 BUG_ON(!ref->wanted_disk_byte);
531 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
David Sterbace86cd52014-06-15 01:07:32 +0200532 0);
Liu Bo64c043d2015-05-25 17:30:15 +0800533 if (IS_ERR(eb)) {
534 return PTR_ERR(eb);
535 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -0400536 free_extent_buffer(eb);
537 return -EIO;
538 }
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200539 btrfs_tree_read_lock(eb);
540 if (btrfs_header_level(eb) == 0)
541 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
542 else
543 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
544 btrfs_tree_read_unlock(eb);
545 free_extent_buffer(eb);
546 }
547 return 0;
548}
549
Jan Schmidt8da6d582011-11-23 18:55:04 +0100550/*
Qu Wenruo00db6462015-04-01 14:39:06 +0800551 * merge backrefs and adjust counts accordingly
Jan Schmidt8da6d582011-11-23 18:55:04 +0100552 *
553 * mode = 1: merge identical keys, if key is set
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200554 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
555 * additionally, we could even add a key range for the blocks we
556 * looked into to merge even more (-> replace unresolved refs by those
557 * having a parent).
Jan Schmidt8da6d582011-11-23 18:55:04 +0100558 * mode = 2: merge identical parents
559 */
Wang Shilong692206b2013-04-11 07:08:55 +0000560static void __merge_refs(struct list_head *head, int mode)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100561{
Geliang Tang8e217852016-01-13 22:08:01 +0800562 struct __prelim_ref *pos1;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100563
Geliang Tang8e217852016-01-13 22:08:01 +0800564 list_for_each_entry(pos1, head, list) {
565 struct __prelim_ref *pos2 = pos1, *tmp;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100566
Geliang Tang8e217852016-01-13 22:08:01 +0800567 list_for_each_entry_safe_continue(pos2, tmp, head, list) {
Dave Jones8f682f62016-01-28 15:28:35 -0500568 struct __prelim_ref *ref1 = pos1, *ref2 = pos2;
Alexander Block3ef59692012-11-08 21:27:24 +0000569 struct extent_inode_elem *eie;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100570
Qu Wenruo00db6462015-04-01 14:39:06 +0800571 if (!ref_for_same_block(ref1, ref2))
572 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100573 if (mode == 1) {
Dave Jones8f682f62016-01-28 15:28:35 -0500574 if (!ref1->parent && ref2->parent)
575 swap(ref1, ref2);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100576 } else {
577 if (ref1->parent != ref2->parent)
578 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100579 }
Alexander Block3ef59692012-11-08 21:27:24 +0000580
581 eie = ref1->inode_list;
582 while (eie && eie->next)
583 eie = eie->next;
584 if (eie)
585 eie->next = ref2->inode_list;
586 else
587 ref1->inode_list = ref2->inode_list;
588 ref1->count += ref2->count;
589
Jan Schmidt8da6d582011-11-23 18:55:04 +0100590 list_del(&ref2->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800591 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
Qu Wenruod8422ba32016-07-20 15:04:18 +0800592 cond_resched();
Jan Schmidt8da6d582011-11-23 18:55:04 +0100593 }
594
595 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100596}
597
598/*
599 * add all currently queued delayed refs from this head whose seq nr is
600 * smaller or equal that seq to the list
601 */
602static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
Josef Bacikdc046b12014-09-10 16:20:45 -0400603 struct list_head *prefs, u64 *total_refs,
604 u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100605{
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800606 struct btrfs_delayed_ref_node *node;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100607 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200608 struct btrfs_key key;
609 struct btrfs_key op_key = {0};
Jan Schmidt8da6d582011-11-23 18:55:04 +0100610 int sgn;
Jan Schmidtb1375d62012-01-26 15:01:11 -0500611 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100612
613 if (extent_op && extent_op->update_key)
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200614 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100615
Josef Bacikd7df2c72014-01-23 09:21:38 -0500616 spin_lock(&head->lock);
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800617 list_for_each_entry(node, &head->ref_list, list) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100618 if (node->seq > seq)
619 continue;
620
621 switch (node->action) {
622 case BTRFS_ADD_DELAYED_EXTENT:
623 case BTRFS_UPDATE_DELAYED_HEAD:
624 WARN_ON(1);
625 continue;
626 case BTRFS_ADD_DELAYED_REF:
627 sgn = 1;
628 break;
629 case BTRFS_DROP_DELAYED_REF:
630 sgn = -1;
631 break;
632 default:
633 BUG_ON(1);
634 }
Josef Bacik44853862014-03-19 13:35:14 -0400635 *total_refs += (node->ref_mod * sgn);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100636 switch (node->type) {
637 case BTRFS_TREE_BLOCK_REF_KEY: {
638 struct btrfs_delayed_tree_ref *ref;
639
640 ref = btrfs_delayed_node_to_tree_ref(node);
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200641 ret = __add_prelim_ref(prefs, ref->root, &op_key,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100642 ref->level + 1, 0, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800643 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100644 break;
645 }
646 case BTRFS_SHARED_BLOCK_REF_KEY: {
647 struct btrfs_delayed_tree_ref *ref;
648
649 ref = btrfs_delayed_node_to_tree_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800650 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100651 ref->level + 1, ref->parent,
652 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800653 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100654 break;
655 }
656 case BTRFS_EXTENT_DATA_REF_KEY: {
657 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100658 ref = btrfs_delayed_node_to_data_ref(node);
659
660 key.objectid = ref->objectid;
661 key.type = BTRFS_EXTENT_DATA_KEY;
662 key.offset = ref->offset;
Josef Bacikdc046b12014-09-10 16:20:45 -0400663
664 /*
665 * Found a inum that doesn't match our known inum, we
666 * know it's shared.
667 */
668 if (inum && ref->objectid != inum) {
669 ret = BACKREF_FOUND_SHARED;
670 break;
671 }
672
Jan Schmidt8da6d582011-11-23 18:55:04 +0100673 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
674 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800675 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100676 break;
677 }
678 case BTRFS_SHARED_DATA_REF_KEY: {
679 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100680
681 ref = btrfs_delayed_node_to_data_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800682 ret = __add_prelim_ref(prefs, 0, NULL, 0,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100683 ref->parent, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800684 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100685 break;
686 }
687 default:
688 WARN_ON(1);
689 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000690 if (ret)
Josef Bacikd7df2c72014-01-23 09:21:38 -0500691 break;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100692 }
Josef Bacikd7df2c72014-01-23 09:21:38 -0500693 spin_unlock(&head->lock);
694 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100695}
696
697/*
698 * add all inline backrefs for bytenr to the list
699 */
700static int __add_inline_refs(struct btrfs_fs_info *fs_info,
701 struct btrfs_path *path, u64 bytenr,
Josef Bacik44853862014-03-19 13:35:14 -0400702 int *info_level, struct list_head *prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -0400703 u64 *total_refs, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100704{
Jan Schmidtb1375d62012-01-26 15:01:11 -0500705 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100706 int slot;
707 struct extent_buffer *leaf;
708 struct btrfs_key key;
Josef Bacik261c84b2013-06-28 13:11:22 -0400709 struct btrfs_key found_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100710 unsigned long ptr;
711 unsigned long end;
712 struct btrfs_extent_item *ei;
713 u64 flags;
714 u64 item_size;
715
716 /*
717 * enumerate all inline refs
718 */
719 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +0200720 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100721
722 item_size = btrfs_item_size_nr(leaf, slot);
723 BUG_ON(item_size < sizeof(*ei));
724
725 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
726 flags = btrfs_extent_flags(leaf, ei);
Josef Bacik44853862014-03-19 13:35:14 -0400727 *total_refs += btrfs_extent_refs(leaf, ei);
Josef Bacik261c84b2013-06-28 13:11:22 -0400728 btrfs_item_key_to_cpu(leaf, &found_key, slot);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100729
730 ptr = (unsigned long)(ei + 1);
731 end = (unsigned long)ei + item_size;
732
Josef Bacik261c84b2013-06-28 13:11:22 -0400733 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
734 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100735 struct btrfs_tree_block_info *info;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100736
737 info = (struct btrfs_tree_block_info *)ptr;
738 *info_level = btrfs_tree_block_level(leaf, info);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100739 ptr += sizeof(struct btrfs_tree_block_info);
740 BUG_ON(ptr > end);
Josef Bacik261c84b2013-06-28 13:11:22 -0400741 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
742 *info_level = found_key.offset;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100743 } else {
744 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
745 }
746
747 while (ptr < end) {
748 struct btrfs_extent_inline_ref *iref;
749 u64 offset;
750 int type;
751
752 iref = (struct btrfs_extent_inline_ref *)ptr;
753 type = btrfs_extent_inline_ref_type(leaf, iref);
754 offset = btrfs_extent_inline_ref_offset(leaf, iref);
755
756 switch (type) {
757 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200758 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100759 *info_level + 1, offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800760 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100761 break;
762 case BTRFS_SHARED_DATA_REF_KEY: {
763 struct btrfs_shared_data_ref *sdref;
764 int count;
765
766 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
767 count = btrfs_shared_data_ref_count(leaf, sdref);
768 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800769 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100770 break;
771 }
772 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200773 ret = __add_prelim_ref(prefs, offset, NULL,
774 *info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800775 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100776 break;
777 case BTRFS_EXTENT_DATA_REF_KEY: {
778 struct btrfs_extent_data_ref *dref;
779 int count;
780 u64 root;
781
782 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
783 count = btrfs_extent_data_ref_count(leaf, dref);
784 key.objectid = btrfs_extent_data_ref_objectid(leaf,
785 dref);
786 key.type = BTRFS_EXTENT_DATA_KEY;
787 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -0400788
789 if (inum && key.objectid != inum) {
790 ret = BACKREF_FOUND_SHARED;
791 break;
792 }
793
Jan Schmidt8da6d582011-11-23 18:55:04 +0100794 root = btrfs_extent_data_ref_root(leaf, dref);
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200795 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800796 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100797 break;
798 }
799 default:
800 WARN_ON(1);
801 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000802 if (ret)
803 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100804 ptr += btrfs_extent_inline_ref_size(type);
805 }
806
807 return 0;
808}
809
810/*
811 * add all non-inline backrefs for bytenr to the list
812 */
813static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
814 struct btrfs_path *path, u64 bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -0400815 int info_level, struct list_head *prefs, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100816{
817 struct btrfs_root *extent_root = fs_info->extent_root;
818 int ret;
819 int slot;
820 struct extent_buffer *leaf;
821 struct btrfs_key key;
822
823 while (1) {
824 ret = btrfs_next_item(extent_root, path);
825 if (ret < 0)
826 break;
827 if (ret) {
828 ret = 0;
829 break;
830 }
831
832 slot = path->slots[0];
833 leaf = path->nodes[0];
834 btrfs_item_key_to_cpu(leaf, &key, slot);
835
836 if (key.objectid != bytenr)
837 break;
838 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
839 continue;
840 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
841 break;
842
843 switch (key.type) {
844 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200845 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100846 info_level + 1, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800847 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100848 break;
849 case BTRFS_SHARED_DATA_REF_KEY: {
850 struct btrfs_shared_data_ref *sdref;
851 int count;
852
853 sdref = btrfs_item_ptr(leaf, slot,
854 struct btrfs_shared_data_ref);
855 count = btrfs_shared_data_ref_count(leaf, sdref);
856 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800857 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100858 break;
859 }
860 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200861 ret = __add_prelim_ref(prefs, key.offset, NULL,
862 info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800863 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100864 break;
865 case BTRFS_EXTENT_DATA_REF_KEY: {
866 struct btrfs_extent_data_ref *dref;
867 int count;
868 u64 root;
869
870 dref = btrfs_item_ptr(leaf, slot,
871 struct btrfs_extent_data_ref);
872 count = btrfs_extent_data_ref_count(leaf, dref);
873 key.objectid = btrfs_extent_data_ref_objectid(leaf,
874 dref);
875 key.type = BTRFS_EXTENT_DATA_KEY;
876 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -0400877
878 if (inum && key.objectid != inum) {
879 ret = BACKREF_FOUND_SHARED;
880 break;
881 }
882
Jan Schmidt8da6d582011-11-23 18:55:04 +0100883 root = btrfs_extent_data_ref_root(leaf, dref);
884 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800885 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100886 break;
887 }
888 default:
889 WARN_ON(1);
890 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000891 if (ret)
892 return ret;
893
Jan Schmidt8da6d582011-11-23 18:55:04 +0100894 }
895
896 return ret;
897}
898
899/*
900 * this adds all existing backrefs (inline backrefs, backrefs and delayed
901 * refs) for the given bytenr to the refs list, merges duplicates and resolves
902 * indirect refs to their parent bytenr.
903 * When roots are found, they're added to the roots list
904 *
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -0700905 * NOTE: This can return values > 0
906 *
Qu Wenruo21633fc2015-04-16 14:54:50 +0800907 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
908 * much like trans == NULL case, the difference only lies in it will not
909 * commit root.
910 * The special case is for qgroup to search roots in commit_transaction().
911 *
Jan Schmidt8da6d582011-11-23 18:55:04 +0100912 * FIXME some caching might speed things up
913 */
914static int find_parent_nodes(struct btrfs_trans_handle *trans,
915 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +0200916 u64 time_seq, struct ulist *refs,
Josef Bacikdc046b12014-09-10 16:20:45 -0400917 struct ulist *roots, const u64 *extent_item_pos,
918 u64 root_objectid, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100919{
920 struct btrfs_key key;
921 struct btrfs_path *path;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100922 struct btrfs_delayed_ref_root *delayed_refs = NULL;
Li Zefand3b01062012-03-03 07:41:15 -0500923 struct btrfs_delayed_ref_head *head;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100924 int info_level = 0;
925 int ret;
926 struct list_head prefs_delayed;
927 struct list_head prefs;
928 struct __prelim_ref *ref;
Wang Shilongf05c4742014-01-28 19:13:38 +0800929 struct extent_inode_elem *eie = NULL;
Josef Bacik44853862014-03-19 13:35:14 -0400930 u64 total_refs = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100931
932 INIT_LIST_HEAD(&prefs);
933 INIT_LIST_HEAD(&prefs_delayed);
934
935 key.objectid = bytenr;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100936 key.offset = (u64)-1;
Josef Bacik261c84b2013-06-28 13:11:22 -0400937 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
938 key.type = BTRFS_METADATA_ITEM_KEY;
939 else
940 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100941
942 path = btrfs_alloc_path();
943 if (!path)
944 return -ENOMEM;
Wang Shilonge84752d2014-02-13 11:19:47 +0800945 if (!trans) {
Josef Bacikda61d312013-06-12 16:20:08 -0400946 path->search_commit_root = 1;
Wang Shilonge84752d2014-02-13 11:19:47 +0800947 path->skip_locking = 1;
948 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100949
Qu Wenruo21633fc2015-04-16 14:54:50 +0800950 if (time_seq == (u64)-1)
951 path->skip_locking = 1;
952
Jan Schmidt8da6d582011-11-23 18:55:04 +0100953 /*
954 * grab both a lock on the path and a lock on the delayed ref head.
955 * We need both to get a consistent picture of how the refs look
956 * at a specified point in time
957 */
958again:
Li Zefand3b01062012-03-03 07:41:15 -0500959 head = NULL;
960
Jan Schmidt8da6d582011-11-23 18:55:04 +0100961 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
962 if (ret < 0)
963 goto out;
964 BUG_ON(ret == 0);
965
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400966#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
Qu Wenruo21633fc2015-04-16 14:54:50 +0800967 if (trans && likely(trans->type != __TRANS_DUMMY) &&
968 time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400969#else
Qu Wenruo21633fc2015-04-16 14:54:50 +0800970 if (trans && time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400971#endif
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100972 /*
973 * look if there are updates for this ref queued and lock the
974 * head
975 */
976 delayed_refs = &trans->transaction->delayed_refs;
977 spin_lock(&delayed_refs->lock);
978 head = btrfs_find_delayed_ref_head(trans, bytenr);
979 if (head) {
980 if (!mutex_trylock(&head->mutex)) {
981 atomic_inc(&head->node.refs);
982 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100983
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100984 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100985
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100986 /*
987 * Mutex was contended, block until it's
988 * released and try again
989 */
990 mutex_lock(&head->mutex);
991 mutex_unlock(&head->mutex);
992 btrfs_put_delayed_ref(&head->node);
993 goto again;
994 }
Josef Bacikd7df2c72014-01-23 09:21:38 -0500995 spin_unlock(&delayed_refs->lock);
Jan Schmidt097b8a72012-06-21 11:08:04 +0200996 ret = __add_delayed_refs(head, time_seq,
Josef Bacikdc046b12014-09-10 16:20:45 -0400997 &prefs_delayed, &total_refs,
998 inum);
Jan Schmidt155725c2012-06-22 14:01:00 +0200999 mutex_unlock(&head->mutex);
Josef Bacikd7df2c72014-01-23 09:21:38 -05001000 if (ret)
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001001 goto out;
Josef Bacikd7df2c72014-01-23 09:21:38 -05001002 } else {
1003 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001004 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001005 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001006
1007 if (path->slots[0]) {
1008 struct extent_buffer *leaf;
1009 int slot;
1010
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001011 path->slots[0]--;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001012 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001013 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +01001014 btrfs_item_key_to_cpu(leaf, &key, slot);
1015 if (key.objectid == bytenr &&
Josef Bacik261c84b2013-06-28 13:11:22 -04001016 (key.type == BTRFS_EXTENT_ITEM_KEY ||
1017 key.type == BTRFS_METADATA_ITEM_KEY)) {
Jan Schmidt8da6d582011-11-23 18:55:04 +01001018 ret = __add_inline_refs(fs_info, path, bytenr,
Josef Bacik44853862014-03-19 13:35:14 -04001019 &info_level, &prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001020 &total_refs, inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001021 if (ret)
1022 goto out;
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001023 ret = __add_keyed_refs(fs_info, path, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001024 info_level, &prefs, inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001025 if (ret)
1026 goto out;
1027 }
1028 }
1029 btrfs_release_path(path);
1030
Jan Schmidt8da6d582011-11-23 18:55:04 +01001031 list_splice_init(&prefs_delayed, &prefs);
1032
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001033 ret = __add_missing_keys(fs_info, &prefs);
1034 if (ret)
1035 goto out;
1036
Wang Shilong692206b2013-04-11 07:08:55 +00001037 __merge_refs(&prefs, 1);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001038
Josef Bacikda61d312013-06-12 16:20:08 -04001039 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001040 extent_item_pos, total_refs,
1041 root_objectid);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001042 if (ret)
1043 goto out;
1044
Wang Shilong692206b2013-04-11 07:08:55 +00001045 __merge_refs(&prefs, 2);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001046
1047 while (!list_empty(&prefs)) {
1048 ref = list_first_entry(&prefs, struct __prelim_ref, list);
Julia Lawall6c1500f2012-11-03 20:30:18 +00001049 WARN_ON(ref->count < 0);
Wang Shilong98cfee212014-02-01 00:42:05 +08001050 if (roots && ref->count && ref->root_id && ref->parent == 0) {
Josef Bacikdc046b12014-09-10 16:20:45 -04001051 if (root_objectid && ref->root_id != root_objectid) {
1052 ret = BACKREF_FOUND_SHARED;
1053 goto out;
1054 }
1055
Jan Schmidt8da6d582011-11-23 18:55:04 +01001056 /* no parent == root of tree */
1057 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001058 if (ret < 0)
1059 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001060 }
1061 if (ref->count && ref->parent) {
Josef Bacik8a564572014-06-05 16:08:45 -04001062 if (extent_item_pos && !ref->inode_list &&
1063 ref->level == 0) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001064 struct extent_buffer *eb;
David Sterba707e8a02014-06-04 19:22:26 +02001065
Jan Schmidt976b1902012-05-17 16:43:03 +02001066 eb = read_tree_block(fs_info->extent_root,
David Sterbace86cd52014-06-15 01:07:32 +02001067 ref->parent, 0);
Liu Bo64c043d2015-05-25 17:30:15 +08001068 if (IS_ERR(eb)) {
1069 ret = PTR_ERR(eb);
1070 goto out;
1071 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -04001072 free_extent_buffer(eb);
Wang Shilongc16c2e22013-05-08 08:10:25 +00001073 ret = -EIO;
1074 goto out;
Josef Bacik416bc652013-04-23 14:17:42 -04001075 }
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001076 btrfs_tree_read_lock(eb);
1077 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidt976b1902012-05-17 16:43:03 +02001078 ret = find_extent_in_eb(eb, bytenr,
1079 *extent_item_pos, &eie);
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001080 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidt976b1902012-05-17 16:43:03 +02001081 free_extent_buffer(eb);
Filipe David Borba Mananaf5929cd2013-07-31 00:26:35 +01001082 if (ret < 0)
1083 goto out;
1084 ref->inode_list = eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001085 }
Takashi Iwai4eb1f662014-07-28 10:57:04 +02001086 ret = ulist_add_merge_ptr(refs, ref->parent,
1087 ref->inode_list,
1088 (void **)&eie, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001089 if (ret < 0)
1090 goto out;
Jan Schmidt33019582012-05-30 18:05:21 +02001091 if (!ret && extent_item_pos) {
1092 /*
1093 * we've recorded that parent, so we must extend
1094 * its inode list here
1095 */
1096 BUG_ON(!eie);
1097 while (eie->next)
1098 eie = eie->next;
1099 eie->next = ref->inode_list;
1100 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001101 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001102 }
Wang Shilonga4fdb612013-08-08 13:04:17 +08001103 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001104 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001105 }
1106
1107out:
Jan Schmidt8da6d582011-11-23 18:55:04 +01001108 btrfs_free_path(path);
1109 while (!list_empty(&prefs)) {
1110 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1111 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001112 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001113 }
1114 while (!list_empty(&prefs_delayed)) {
1115 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1116 list);
1117 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001118 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001119 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001120 if (ret < 0)
1121 free_inode_elem_list(eie);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001122 return ret;
1123}
1124
Jan Schmidt976b1902012-05-17 16:43:03 +02001125static void free_leaf_list(struct ulist *blocks)
1126{
1127 struct ulist_node *node = NULL;
1128 struct extent_inode_elem *eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001129 struct ulist_iterator uiter;
1130
1131 ULIST_ITER_INIT(&uiter);
1132 while ((node = ulist_next(blocks, &uiter))) {
1133 if (!node->aux)
1134 continue;
Jan Schmidt995e01b2012-08-13 02:52:38 -06001135 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
Wang Shilongf05c4742014-01-28 19:13:38 +08001136 free_inode_elem_list(eie);
Jan Schmidt976b1902012-05-17 16:43:03 +02001137 node->aux = 0;
1138 }
1139
1140 ulist_free(blocks);
1141}
1142
Jan Schmidt8da6d582011-11-23 18:55:04 +01001143/*
1144 * Finds all leafs with a reference to the specified combination of bytenr and
1145 * offset. key_list_head will point to a list of corresponding keys (caller must
1146 * free each list element). The leafs will be stored in the leafs ulist, which
1147 * must be freed with ulist_free.
1148 *
1149 * returns 0 on success, <0 on error
1150 */
1151static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1152 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001153 u64 time_seq, struct ulist **leafs,
Jan Schmidt976b1902012-05-17 16:43:03 +02001154 const u64 *extent_item_pos)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001155{
Jan Schmidt8da6d582011-11-23 18:55:04 +01001156 int ret;
1157
Jan Schmidt8da6d582011-11-23 18:55:04 +01001158 *leafs = ulist_alloc(GFP_NOFS);
Wang Shilong98cfee212014-02-01 00:42:05 +08001159 if (!*leafs)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001160 return -ENOMEM;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001161
Jan Schmidt097b8a72012-06-21 11:08:04 +02001162 ret = find_parent_nodes(trans, fs_info, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001163 time_seq, *leafs, NULL, extent_item_pos, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001164 if (ret < 0 && ret != -ENOENT) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001165 free_leaf_list(*leafs);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001166 return ret;
1167 }
1168
1169 return 0;
1170}
1171
1172/*
1173 * walk all backrefs for a given extent to find all roots that reference this
1174 * extent. Walking a backref means finding all extents that reference this
1175 * extent and in turn walk the backrefs of those, too. Naturally this is a
1176 * recursive process, but here it is implemented in an iterative fashion: We
1177 * find all referencing extents for the extent in question and put them on a
1178 * list. In turn, we find all referencing extents for those, further appending
1179 * to the list. The way we iterate the list allows adding more elements after
1180 * the current while iterating. The process stops when we reach the end of the
1181 * list. Found roots are added to the roots list.
1182 *
1183 * returns 0 on success, < 0 on error.
1184 */
Josef Bacik9e351cc2014-03-13 15:42:13 -04001185static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1186 struct btrfs_fs_info *fs_info, u64 bytenr,
1187 u64 time_seq, struct ulist **roots)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001188{
1189 struct ulist *tmp;
1190 struct ulist_node *node = NULL;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001191 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001192 int ret;
1193
1194 tmp = ulist_alloc(GFP_NOFS);
1195 if (!tmp)
1196 return -ENOMEM;
1197 *roots = ulist_alloc(GFP_NOFS);
1198 if (!*roots) {
1199 ulist_free(tmp);
1200 return -ENOMEM;
1201 }
1202
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001203 ULIST_ITER_INIT(&uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001204 while (1) {
Jan Schmidt097b8a72012-06-21 11:08:04 +02001205 ret = find_parent_nodes(trans, fs_info, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001206 time_seq, tmp, *roots, NULL, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001207 if (ret < 0 && ret != -ENOENT) {
1208 ulist_free(tmp);
1209 ulist_free(*roots);
1210 return ret;
1211 }
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001212 node = ulist_next(tmp, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001213 if (!node)
1214 break;
1215 bytenr = node->val;
Wang Shilongbca1a292014-01-26 22:32:18 +08001216 cond_resched();
Jan Schmidt8da6d582011-11-23 18:55:04 +01001217 }
1218
1219 ulist_free(tmp);
1220 return 0;
1221}
1222
Josef Bacik9e351cc2014-03-13 15:42:13 -04001223int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1224 struct btrfs_fs_info *fs_info, u64 bytenr,
1225 u64 time_seq, struct ulist **roots)
1226{
1227 int ret;
1228
1229 if (!trans)
1230 down_read(&fs_info->commit_root_sem);
1231 ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1232 if (!trans)
1233 up_read(&fs_info->commit_root_sem);
1234 return ret;
1235}
1236
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001237/**
1238 * btrfs_check_shared - tell us whether an extent is shared
1239 *
1240 * @trans: optional trans handle
1241 *
1242 * btrfs_check_shared uses the backref walking code but will short
1243 * circuit as soon as it finds a root or inode that doesn't match the
1244 * one passed in. This provides a significant performance benefit for
1245 * callers (such as fiemap) which want to know whether the extent is
1246 * shared but do not need a ref count.
1247 *
1248 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1249 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001250int btrfs_check_shared(struct btrfs_trans_handle *trans,
1251 struct btrfs_fs_info *fs_info, u64 root_objectid,
1252 u64 inum, u64 bytenr)
1253{
1254 struct ulist *tmp = NULL;
1255 struct ulist *roots = NULL;
1256 struct ulist_iterator uiter;
1257 struct ulist_node *node;
David Sterba3284da72015-02-25 15:47:32 +01001258 struct seq_list elem = SEQ_LIST_INIT(elem);
Josef Bacikdc046b12014-09-10 16:20:45 -04001259 int ret = 0;
1260
1261 tmp = ulist_alloc(GFP_NOFS);
1262 roots = ulist_alloc(GFP_NOFS);
1263 if (!tmp || !roots) {
1264 ulist_free(tmp);
1265 ulist_free(roots);
1266 return -ENOMEM;
1267 }
1268
1269 if (trans)
1270 btrfs_get_tree_mod_seq(fs_info, &elem);
1271 else
1272 down_read(&fs_info->commit_root_sem);
1273 ULIST_ITER_INIT(&uiter);
1274 while (1) {
1275 ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
1276 roots, NULL, root_objectid, inum);
1277 if (ret == BACKREF_FOUND_SHARED) {
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001278 /* this is the only condition under which we return 1 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001279 ret = 1;
1280 break;
1281 }
1282 if (ret < 0 && ret != -ENOENT)
1283 break;
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001284 ret = 0;
Josef Bacikdc046b12014-09-10 16:20:45 -04001285 node = ulist_next(tmp, &uiter);
1286 if (!node)
1287 break;
1288 bytenr = node->val;
1289 cond_resched();
1290 }
1291 if (trans)
1292 btrfs_put_tree_mod_seq(fs_info, &elem);
1293 else
1294 up_read(&fs_info->commit_root_sem);
1295 ulist_free(tmp);
1296 ulist_free(roots);
1297 return ret;
1298}
1299
Mark Fashehf1863732012-08-08 11:32:27 -07001300int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1301 u64 start_off, struct btrfs_path *path,
1302 struct btrfs_inode_extref **ret_extref,
1303 u64 *found_off)
1304{
1305 int ret, slot;
1306 struct btrfs_key key;
1307 struct btrfs_key found_key;
1308 struct btrfs_inode_extref *extref;
1309 struct extent_buffer *leaf;
1310 unsigned long ptr;
1311
1312 key.objectid = inode_objectid;
David Sterba962a2982014-06-04 18:41:45 +02001313 key.type = BTRFS_INODE_EXTREF_KEY;
Mark Fashehf1863732012-08-08 11:32:27 -07001314 key.offset = start_off;
1315
1316 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1317 if (ret < 0)
1318 return ret;
1319
1320 while (1) {
1321 leaf = path->nodes[0];
1322 slot = path->slots[0];
1323 if (slot >= btrfs_header_nritems(leaf)) {
1324 /*
1325 * If the item at offset is not found,
1326 * btrfs_search_slot will point us to the slot
1327 * where it should be inserted. In our case
1328 * that will be the slot directly before the
1329 * next INODE_REF_KEY_V2 item. In the case
1330 * that we're pointing to the last slot in a
1331 * leaf, we must move one leaf over.
1332 */
1333 ret = btrfs_next_leaf(root, path);
1334 if (ret) {
1335 if (ret >= 1)
1336 ret = -ENOENT;
1337 break;
1338 }
1339 continue;
1340 }
1341
1342 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1343
1344 /*
1345 * Check that we're still looking at an extended ref key for
1346 * this particular objectid. If we have different
1347 * objectid or type then there are no more to be found
1348 * in the tree and we can exit.
1349 */
1350 ret = -ENOENT;
1351 if (found_key.objectid != inode_objectid)
1352 break;
David Sterba962a2982014-06-04 18:41:45 +02001353 if (found_key.type != BTRFS_INODE_EXTREF_KEY)
Mark Fashehf1863732012-08-08 11:32:27 -07001354 break;
1355
1356 ret = 0;
1357 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1358 extref = (struct btrfs_inode_extref *)ptr;
1359 *ret_extref = extref;
1360 if (found_off)
1361 *found_off = found_key.offset;
1362 break;
1363 }
1364
1365 return ret;
1366}
1367
Eric Sandeen48a3b632013-04-25 20:41:01 +00001368/*
1369 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1370 * Elements of the path are separated by '/' and the path is guaranteed to be
1371 * 0-terminated. the path is only given within the current file system.
1372 * Therefore, it never starts with a '/'. the caller is responsible to provide
1373 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1374 * the start point of the resulting string is returned. this pointer is within
1375 * dest, normally.
1376 * in case the path buffer would overflow, the pointer is decremented further
1377 * as if output was written to the buffer, though no more output is actually
1378 * generated. that way, the caller can determine how much space would be
1379 * required for the path to fit into the buffer. in that case, the returned
1380 * value will be smaller than dest. callers must check this!
1381 */
Jan Schmidt96b5bd72012-10-15 08:30:45 +00001382char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1383 u32 name_len, unsigned long name_off,
1384 struct extent_buffer *eb_in, u64 parent,
1385 char *dest, u32 size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001386{
Jan Schmidta542ad12011-06-13 19:52:59 +02001387 int slot;
1388 u64 next_inum;
1389 int ret;
Gabriel de Perthuis661bec62012-10-10 08:50:47 -06001390 s64 bytes_left = ((s64)size) - 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001391 struct extent_buffer *eb = eb_in;
1392 struct btrfs_key found_key;
Jan Schmidtb916a592012-04-13 12:28:08 +02001393 int leave_spinning = path->leave_spinning;
Mark Fashehd24bec32012-08-08 11:33:54 -07001394 struct btrfs_inode_ref *iref;
Jan Schmidta542ad12011-06-13 19:52:59 +02001395
1396 if (bytes_left >= 0)
1397 dest[bytes_left] = '\0';
1398
Jan Schmidtb916a592012-04-13 12:28:08 +02001399 path->leave_spinning = 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001400 while (1) {
Mark Fashehd24bec32012-08-08 11:33:54 -07001401 bytes_left -= name_len;
Jan Schmidta542ad12011-06-13 19:52:59 +02001402 if (bytes_left >= 0)
1403 read_extent_buffer(eb, dest + bytes_left,
Mark Fashehd24bec32012-08-08 11:33:54 -07001404 name_off, name_len);
Jan Schmidtb916a592012-04-13 12:28:08 +02001405 if (eb != eb_in) {
Filipe Manana0c0fe3b2016-02-03 19:17:27 +00001406 if (!path->skip_locking)
1407 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001408 free_extent_buffer(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02001409 }
David Sterbac234a242015-01-02 19:03:17 +01001410 ret = btrfs_find_item(fs_root, path, parent, 0,
1411 BTRFS_INODE_REF_KEY, &found_key);
Jan Schmidt8f24b492012-02-08 16:01:01 +01001412 if (ret > 0)
1413 ret = -ENOENT;
Jan Schmidta542ad12011-06-13 19:52:59 +02001414 if (ret)
1415 break;
Mark Fashehd24bec32012-08-08 11:33:54 -07001416
Jan Schmidta542ad12011-06-13 19:52:59 +02001417 next_inum = found_key.offset;
1418
1419 /* regular exit ahead */
1420 if (parent == next_inum)
1421 break;
1422
1423 slot = path->slots[0];
1424 eb = path->nodes[0];
1425 /* make sure we can use eb after releasing the path */
Jan Schmidtb916a592012-04-13 12:28:08 +02001426 if (eb != eb_in) {
Filipe Manana0c0fe3b2016-02-03 19:17:27 +00001427 if (!path->skip_locking)
1428 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1429 path->nodes[0] = NULL;
1430 path->locks[0] = 0;
Jan Schmidtb916a592012-04-13 12:28:08 +02001431 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001432 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001433 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
Mark Fashehd24bec32012-08-08 11:33:54 -07001434
1435 name_len = btrfs_inode_ref_name_len(eb, iref);
1436 name_off = (unsigned long)(iref + 1);
1437
Jan Schmidta542ad12011-06-13 19:52:59 +02001438 parent = next_inum;
1439 --bytes_left;
1440 if (bytes_left >= 0)
1441 dest[bytes_left] = '/';
1442 }
1443
1444 btrfs_release_path(path);
Jan Schmidtb916a592012-04-13 12:28:08 +02001445 path->leave_spinning = leave_spinning;
Jan Schmidta542ad12011-06-13 19:52:59 +02001446
1447 if (ret)
1448 return ERR_PTR(ret);
1449
1450 return dest + bytes_left;
1451}
1452
1453/*
1454 * this makes the path point to (logical EXTENT_ITEM *)
1455 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1456 * tree blocks and <0 on error.
1457 */
1458int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
Liu Bo69917e42012-09-07 20:01:28 -06001459 struct btrfs_path *path, struct btrfs_key *found_key,
1460 u64 *flags_ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001461{
1462 int ret;
1463 u64 flags;
Josef Bacik261c84b2013-06-28 13:11:22 -04001464 u64 size = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001465 u32 item_size;
1466 struct extent_buffer *eb;
1467 struct btrfs_extent_item *ei;
1468 struct btrfs_key key;
1469
Josef Bacik261c84b2013-06-28 13:11:22 -04001470 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1471 key.type = BTRFS_METADATA_ITEM_KEY;
1472 else
1473 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidta542ad12011-06-13 19:52:59 +02001474 key.objectid = logical;
1475 key.offset = (u64)-1;
1476
1477 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1478 if (ret < 0)
1479 return ret;
Jan Schmidta542ad12011-06-13 19:52:59 +02001480
Wang Shilong850a8cd2014-02-06 20:02:29 +08001481 ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1482 if (ret) {
1483 if (ret > 0)
1484 ret = -ENOENT;
1485 return ret;
Josef Bacik580f0a62014-01-23 16:03:45 -05001486 }
Wang Shilong850a8cd2014-02-06 20:02:29 +08001487 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
Josef Bacik261c84b2013-06-28 13:11:22 -04001488 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
David Sterba707e8a02014-06-04 19:22:26 +02001489 size = fs_info->extent_root->nodesize;
Josef Bacik261c84b2013-06-28 13:11:22 -04001490 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1491 size = found_key->offset;
1492
Josef Bacik580f0a62014-01-23 16:03:45 -05001493 if (found_key->objectid > logical ||
Josef Bacik261c84b2013-06-28 13:11:22 -04001494 found_key->objectid + size <= logical) {
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001495 pr_debug("logical %llu is not within any extent\n", logical);
Jan Schmidta542ad12011-06-13 19:52:59 +02001496 return -ENOENT;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001497 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001498
1499 eb = path->nodes[0];
1500 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1501 BUG_ON(item_size < sizeof(*ei));
1502
1503 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1504 flags = btrfs_extent_flags(eb, ei);
1505
Jan Schmidt4692cf52011-12-02 14:56:41 +01001506 pr_debug("logical %llu is at position %llu within the extent (%llu "
1507 "EXTENT_ITEM %llu) flags %#llx size %u\n",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001508 logical, logical - found_key->objectid, found_key->objectid,
1509 found_key->offset, flags, item_size);
Liu Bo69917e42012-09-07 20:01:28 -06001510
1511 WARN_ON(!flags_ret);
1512 if (flags_ret) {
1513 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1514 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1515 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1516 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1517 else
1518 BUG_ON(1);
1519 return 0;
1520 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001521
1522 return -EIO;
1523}
1524
1525/*
1526 * helper function to iterate extent inline refs. ptr must point to a 0 value
1527 * for the first call and may be modified. it is used to track state.
1528 * if more refs exist, 0 is returned and the next call to
1529 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1530 * next ref. after the last ref was processed, 1 is returned.
1531 * returns <0 on error
1532 */
1533static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001534 struct btrfs_key *key,
1535 struct btrfs_extent_item *ei, u32 item_size,
1536 struct btrfs_extent_inline_ref **out_eiref,
1537 int *out_type)
Jan Schmidta542ad12011-06-13 19:52:59 +02001538{
1539 unsigned long end;
1540 u64 flags;
1541 struct btrfs_tree_block_info *info;
1542
1543 if (!*ptr) {
1544 /* first call */
1545 flags = btrfs_extent_flags(eb, ei);
1546 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001547 if (key->type == BTRFS_METADATA_ITEM_KEY) {
1548 /* a skinny metadata extent */
1549 *out_eiref =
1550 (struct btrfs_extent_inline_ref *)(ei + 1);
1551 } else {
1552 WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1553 info = (struct btrfs_tree_block_info *)(ei + 1);
1554 *out_eiref =
1555 (struct btrfs_extent_inline_ref *)(info + 1);
1556 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001557 } else {
1558 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1559 }
1560 *ptr = (unsigned long)*out_eiref;
Liu Bocd857dd2014-06-08 19:04:13 +08001561 if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001562 return -ENOENT;
1563 }
1564
1565 end = (unsigned long)ei + item_size;
Liu Bo6eda71d2014-06-09 10:54:07 +08001566 *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
Jan Schmidta542ad12011-06-13 19:52:59 +02001567 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1568
1569 *ptr += btrfs_extent_inline_ref_size(*out_type);
1570 WARN_ON(*ptr > end);
1571 if (*ptr == end)
1572 return 1; /* last */
1573
1574 return 0;
1575}
1576
1577/*
1578 * reads the tree block backref for an extent. tree level and root are returned
1579 * through out_level and out_root. ptr must point to a 0 value for the first
1580 * call and may be modified (see __get_extent_inline_ref comment).
1581 * returns 0 if data was provided, 1 if there was no more data to provide or
1582 * <0 on error.
1583 */
1584int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001585 struct btrfs_key *key, struct btrfs_extent_item *ei,
1586 u32 item_size, u64 *out_root, u8 *out_level)
Jan Schmidta542ad12011-06-13 19:52:59 +02001587{
1588 int ret;
1589 int type;
Jan Schmidta542ad12011-06-13 19:52:59 +02001590 struct btrfs_extent_inline_ref *eiref;
1591
1592 if (*ptr == (unsigned long)-1)
1593 return 1;
1594
1595 while (1) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001596 ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1597 &eiref, &type);
Jan Schmidta542ad12011-06-13 19:52:59 +02001598 if (ret < 0)
1599 return ret;
1600
1601 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1602 type == BTRFS_SHARED_BLOCK_REF_KEY)
1603 break;
1604
1605 if (ret == 1)
1606 return 1;
1607 }
1608
1609 /* we can treat both ref types equally here */
Jan Schmidta542ad12011-06-13 19:52:59 +02001610 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
Filipe Mananaa1317f42014-12-15 16:04:42 +00001611
1612 if (key->type == BTRFS_EXTENT_ITEM_KEY) {
1613 struct btrfs_tree_block_info *info;
1614
1615 info = (struct btrfs_tree_block_info *)(ei + 1);
1616 *out_level = btrfs_tree_block_level(eb, info);
1617 } else {
1618 ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
1619 *out_level = (u8)key->offset;
1620 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001621
1622 if (ret == 1)
1623 *ptr = (unsigned long)-1;
1624
1625 return 0;
1626}
1627
Jan Schmidt976b1902012-05-17 16:43:03 +02001628static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1629 u64 root, u64 extent_item_objectid,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001630 iterate_extent_inodes_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001631{
Jan Schmidt976b1902012-05-17 16:43:03 +02001632 struct extent_inode_elem *eie;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001633 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001634
Jan Schmidt976b1902012-05-17 16:43:03 +02001635 for (eie = inode_list; eie; eie = eie->next) {
Jan Schmidt4692cf52011-12-02 14:56:41 +01001636 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
Jan Schmidt976b1902012-05-17 16:43:03 +02001637 "root %llu\n", extent_item_objectid,
1638 eie->inum, eie->offset, root);
1639 ret = iterate(eie->inum, eie->offset, root, ctx);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001640 if (ret) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001641 pr_debug("stopping iteration for %llu due to ret=%d\n",
1642 extent_item_objectid, ret);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001643 break;
1644 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001645 }
1646
Jan Schmidta542ad12011-06-13 19:52:59 +02001647 return ret;
1648}
1649
1650/*
1651 * calls iterate() for every inode that references the extent identified by
Jan Schmidt4692cf52011-12-02 14:56:41 +01001652 * the given parameters.
Jan Schmidta542ad12011-06-13 19:52:59 +02001653 * when the iterator function returns a non-zero value, iteration stops.
1654 */
1655int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001656 u64 extent_item_objectid, u64 extent_item_pos,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001657 int search_commit_root,
Jan Schmidta542ad12011-06-13 19:52:59 +02001658 iterate_extent_inodes_t *iterate, void *ctx)
1659{
Jan Schmidta542ad12011-06-13 19:52:59 +02001660 int ret;
Josef Bacikda61d312013-06-12 16:20:08 -04001661 struct btrfs_trans_handle *trans = NULL;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001662 struct ulist *refs = NULL;
1663 struct ulist *roots = NULL;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001664 struct ulist_node *ref_node = NULL;
1665 struct ulist_node *root_node = NULL;
David Sterba3284da72015-02-25 15:47:32 +01001666 struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001667 struct ulist_iterator ref_uiter;
1668 struct ulist_iterator root_uiter;
Jan Schmidta542ad12011-06-13 19:52:59 +02001669
Jan Schmidt4692cf52011-12-02 14:56:41 +01001670 pr_debug("resolving all inodes for extent %llu\n",
1671 extent_item_objectid);
1672
Josef Bacikda61d312013-06-12 16:20:08 -04001673 if (!search_commit_root) {
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001674 trans = btrfs_join_transaction(fs_info->extent_root);
1675 if (IS_ERR(trans))
1676 return PTR_ERR(trans);
Jan Schmidt8445f612012-05-16 18:36:03 +02001677 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Josef Bacik9e351cc2014-03-13 15:42:13 -04001678 } else {
1679 down_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001680 }
Jan Schmidt4692cf52011-12-02 14:56:41 +01001681
1682 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001683 tree_mod_seq_elem.seq, &refs,
Jan Schmidt8445f612012-05-16 18:36:03 +02001684 &extent_item_pos);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001685 if (ret)
1686 goto out;
1687
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001688 ULIST_ITER_INIT(&ref_uiter);
1689 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
Josef Bacik9e351cc2014-03-13 15:42:13 -04001690 ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
1691 tree_mod_seq_elem.seq, &roots);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001692 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001693 break;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001694 ULIST_ITER_INIT(&root_uiter);
1695 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001696 pr_debug("root %llu references leaf %llu, data list "
Alexander Block34d73f52012-07-28 16:18:58 +02001697 "%#llx\n", root_node->val, ref_node->val,
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001698 ref_node->aux);
Jan Schmidt995e01b2012-08-13 02:52:38 -06001699 ret = iterate_leaf_refs((struct extent_inode_elem *)
1700 (uintptr_t)ref_node->aux,
1701 root_node->val,
1702 extent_item_objectid,
1703 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001704 }
Jan Schmidt976b1902012-05-17 16:43:03 +02001705 ulist_free(roots);
Jan Schmidta542ad12011-06-13 19:52:59 +02001706 }
1707
Jan Schmidt976b1902012-05-17 16:43:03 +02001708 free_leaf_list(refs);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001709out:
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001710 if (!search_commit_root) {
Jan Schmidt8445f612012-05-16 18:36:03 +02001711 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001712 btrfs_end_transaction(trans, fs_info->extent_root);
Josef Bacik9e351cc2014-03-13 15:42:13 -04001713 } else {
1714 up_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001715 }
1716
Jan Schmidta542ad12011-06-13 19:52:59 +02001717 return ret;
1718}
1719
1720int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1721 struct btrfs_path *path,
1722 iterate_extent_inodes_t *iterate, void *ctx)
1723{
1724 int ret;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001725 u64 extent_item_pos;
Liu Bo69917e42012-09-07 20:01:28 -06001726 u64 flags = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001727 struct btrfs_key found_key;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001728 int search_commit_root = path->search_commit_root;
Jan Schmidta542ad12011-06-13 19:52:59 +02001729
Liu Bo69917e42012-09-07 20:01:28 -06001730 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001731 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001732 if (ret < 0)
1733 return ret;
Liu Bo69917e42012-09-07 20:01:28 -06001734 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
Stefan Behrens3627bf42012-08-01 04:28:01 -06001735 return -EINVAL;
Jan Schmidta542ad12011-06-13 19:52:59 +02001736
Jan Schmidt4692cf52011-12-02 14:56:41 +01001737 extent_item_pos = logical - found_key.objectid;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001738 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1739 extent_item_pos, search_commit_root,
1740 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001741
1742 return ret;
1743}
1744
Mark Fashehd24bec32012-08-08 11:33:54 -07001745typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1746 struct extent_buffer *eb, void *ctx);
1747
1748static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1749 struct btrfs_path *path,
1750 iterate_irefs_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001751{
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001752 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001753 int slot;
1754 u32 cur;
1755 u32 len;
1756 u32 name_len;
1757 u64 parent = 0;
1758 int found = 0;
1759 struct extent_buffer *eb;
1760 struct btrfs_item *item;
1761 struct btrfs_inode_ref *iref;
1762 struct btrfs_key found_key;
1763
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001764 while (!ret) {
David Sterbac234a242015-01-02 19:03:17 +01001765 ret = btrfs_find_item(fs_root, path, inum,
1766 parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
1767 &found_key);
1768
Jan Schmidta542ad12011-06-13 19:52:59 +02001769 if (ret < 0)
1770 break;
1771 if (ret) {
1772 ret = found ? 0 : -ENOENT;
1773 break;
1774 }
1775 ++found;
1776
1777 parent = found_key.offset;
1778 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00001779 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1780 if (!eb) {
1781 ret = -ENOMEM;
1782 break;
1783 }
1784 extent_buffer_get(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02001785 btrfs_tree_read_lock(eb);
1786 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidta542ad12011-06-13 19:52:59 +02001787 btrfs_release_path(path);
1788
Ross Kirkdd3cc162013-09-16 15:58:09 +01001789 item = btrfs_item_nr(slot);
Jan Schmidta542ad12011-06-13 19:52:59 +02001790 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1791
1792 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1793 name_len = btrfs_inode_ref_name_len(eb, iref);
1794 /* path must be released before calling iterate()! */
Jan Schmidt4692cf52011-12-02 14:56:41 +01001795 pr_debug("following ref at offset %u for inode %llu in "
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001796 "tree %llu\n", cur, found_key.objectid,
1797 fs_root->objectid);
Mark Fashehd24bec32012-08-08 11:33:54 -07001798 ret = iterate(parent, name_len,
1799 (unsigned long)(iref + 1), eb, ctx);
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001800 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001801 break;
Jan Schmidta542ad12011-06-13 19:52:59 +02001802 len = sizeof(*iref) + name_len;
1803 iref = (struct btrfs_inode_ref *)((char *)iref + len);
1804 }
Jan Schmidtb916a592012-04-13 12:28:08 +02001805 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001806 free_extent_buffer(eb);
1807 }
1808
1809 btrfs_release_path(path);
1810
1811 return ret;
1812}
1813
Mark Fashehd24bec32012-08-08 11:33:54 -07001814static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1815 struct btrfs_path *path,
1816 iterate_irefs_t *iterate, void *ctx)
1817{
1818 int ret;
1819 int slot;
1820 u64 offset = 0;
1821 u64 parent;
1822 int found = 0;
1823 struct extent_buffer *eb;
1824 struct btrfs_inode_extref *extref;
Mark Fashehd24bec32012-08-08 11:33:54 -07001825 u32 item_size;
1826 u32 cur_offset;
1827 unsigned long ptr;
1828
1829 while (1) {
1830 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1831 &offset);
1832 if (ret < 0)
1833 break;
1834 if (ret) {
1835 ret = found ? 0 : -ENOENT;
1836 break;
1837 }
1838 ++found;
1839
1840 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00001841 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1842 if (!eb) {
1843 ret = -ENOMEM;
1844 break;
1845 }
1846 extent_buffer_get(eb);
Mark Fashehd24bec32012-08-08 11:33:54 -07001847
1848 btrfs_tree_read_lock(eb);
1849 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1850 btrfs_release_path(path);
1851
Chris Mason2849a852015-10-13 14:06:48 -04001852 item_size = btrfs_item_size_nr(eb, slot);
1853 ptr = btrfs_item_ptr_offset(eb, slot);
Mark Fashehd24bec32012-08-08 11:33:54 -07001854 cur_offset = 0;
1855
1856 while (cur_offset < item_size) {
1857 u32 name_len;
1858
1859 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1860 parent = btrfs_inode_extref_parent(eb, extref);
1861 name_len = btrfs_inode_extref_name_len(eb, extref);
1862 ret = iterate(parent, name_len,
1863 (unsigned long)&extref->name, eb, ctx);
1864 if (ret)
1865 break;
1866
Chris Mason2849a852015-10-13 14:06:48 -04001867 cur_offset += btrfs_inode_extref_name_len(eb, extref);
Mark Fashehd24bec32012-08-08 11:33:54 -07001868 cur_offset += sizeof(*extref);
1869 }
1870 btrfs_tree_read_unlock_blocking(eb);
1871 free_extent_buffer(eb);
1872
1873 offset++;
1874 }
1875
1876 btrfs_release_path(path);
1877
1878 return ret;
1879}
1880
1881static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1882 struct btrfs_path *path, iterate_irefs_t *iterate,
1883 void *ctx)
1884{
1885 int ret;
1886 int found_refs = 0;
1887
1888 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1889 if (!ret)
1890 ++found_refs;
1891 else if (ret != -ENOENT)
1892 return ret;
1893
1894 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1895 if (ret == -ENOENT && found_refs)
1896 return 0;
1897
1898 return ret;
1899}
1900
Jan Schmidta542ad12011-06-13 19:52:59 +02001901/*
1902 * returns 0 if the path could be dumped (probably truncated)
1903 * returns <0 in case of an error
1904 */
Mark Fashehd24bec32012-08-08 11:33:54 -07001905static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1906 struct extent_buffer *eb, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001907{
1908 struct inode_fs_paths *ipath = ctx;
1909 char *fspath;
1910 char *fspath_min;
1911 int i = ipath->fspath->elem_cnt;
1912 const int s_ptr = sizeof(char *);
1913 u32 bytes_left;
1914
1915 bytes_left = ipath->fspath->bytes_left > s_ptr ?
1916 ipath->fspath->bytes_left - s_ptr : 0;
1917
Chris Mason740c3d22011-11-02 15:48:34 -04001918 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
Jan Schmidt96b5bd72012-10-15 08:30:45 +00001919 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1920 name_off, eb, inum, fspath_min, bytes_left);
Jan Schmidta542ad12011-06-13 19:52:59 +02001921 if (IS_ERR(fspath))
1922 return PTR_ERR(fspath);
1923
1924 if (fspath > fspath_min) {
Jeff Mahoney745c4d82011-11-20 07:31:57 -05001925 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
Jan Schmidta542ad12011-06-13 19:52:59 +02001926 ++ipath->fspath->elem_cnt;
1927 ipath->fspath->bytes_left = fspath - fspath_min;
1928 } else {
1929 ++ipath->fspath->elem_missed;
1930 ipath->fspath->bytes_missing += fspath_min - fspath;
1931 ipath->fspath->bytes_left = 0;
1932 }
1933
1934 return 0;
1935}
1936
1937/*
1938 * this dumps all file system paths to the inode into the ipath struct, provided
1939 * is has been created large enough. each path is zero-terminated and accessed
Chris Mason740c3d22011-11-02 15:48:34 -04001940 * from ipath->fspath->val[i].
Jan Schmidta542ad12011-06-13 19:52:59 +02001941 * when it returns, there are ipath->fspath->elem_cnt number of paths available
Chris Mason740c3d22011-11-02 15:48:34 -04001942 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
Nicholas D Steeves01327612016-05-19 21:18:45 -04001943 * number of missed paths is recorded in ipath->fspath->elem_missed, otherwise,
Jan Schmidta542ad12011-06-13 19:52:59 +02001944 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1945 * have been needed to return all paths.
1946 */
1947int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1948{
1949 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
Mark Fashehd24bec32012-08-08 11:33:54 -07001950 inode_to_path, ipath);
Jan Schmidta542ad12011-06-13 19:52:59 +02001951}
1952
Jan Schmidta542ad12011-06-13 19:52:59 +02001953struct btrfs_data_container *init_data_container(u32 total_bytes)
1954{
1955 struct btrfs_data_container *data;
1956 size_t alloc_bytes;
1957
1958 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
Liu Bo425d17a2012-09-07 20:01:30 -06001959 data = vmalloc(alloc_bytes);
Jan Schmidta542ad12011-06-13 19:52:59 +02001960 if (!data)
1961 return ERR_PTR(-ENOMEM);
1962
1963 if (total_bytes >= sizeof(*data)) {
1964 data->bytes_left = total_bytes - sizeof(*data);
1965 data->bytes_missing = 0;
1966 } else {
1967 data->bytes_missing = sizeof(*data) - total_bytes;
1968 data->bytes_left = 0;
1969 }
1970
1971 data->elem_cnt = 0;
1972 data->elem_missed = 0;
1973
1974 return data;
1975}
1976
1977/*
1978 * allocates space to return multiple file system paths for an inode.
1979 * total_bytes to allocate are passed, note that space usable for actual path
1980 * information will be total_bytes - sizeof(struct inode_fs_paths).
1981 * the returned pointer must be freed with free_ipath() in the end.
1982 */
1983struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1984 struct btrfs_path *path)
1985{
1986 struct inode_fs_paths *ifp;
1987 struct btrfs_data_container *fspath;
1988
1989 fspath = init_data_container(total_bytes);
1990 if (IS_ERR(fspath))
1991 return (void *)fspath;
1992
1993 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1994 if (!ifp) {
Vincent Stehlé72928f22016-05-10 14:56:20 +02001995 vfree(fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02001996 return ERR_PTR(-ENOMEM);
1997 }
1998
1999 ifp->btrfs_path = path;
2000 ifp->fspath = fspath;
2001 ifp->fs_root = fs_root;
2002
2003 return ifp;
2004}
2005
2006void free_ipath(struct inode_fs_paths *ipath)
2007{
Jesper Juhl4735fb22012-04-12 22:47:52 +02002008 if (!ipath)
2009 return;
Liu Bo425d17a2012-09-07 20:01:30 -06002010 vfree(ipath->fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02002011 kfree(ipath);
2012}