blob: d453d62ab0c6e322b3c0df0a05b20daa6751d5ad [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,
142 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
143 NULL);
144 if (!btrfs_prelim_ref_cache)
145 return -ENOMEM;
146 return 0;
147}
148
149void btrfs_prelim_ref_exit(void)
150{
151 if (btrfs_prelim_ref_cache)
152 kmem_cache_destroy(btrfs_prelim_ref_cache);
153}
154
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200155/*
156 * the rules for all callers of this function are:
157 * - obtaining the parent is the goal
158 * - if you add a key, you must know that it is a correct key
159 * - if you cannot add the parent or a correct key, then we will look into the
160 * block later to set a correct key
161 *
162 * delayed refs
163 * ============
164 * backref type | shared | indirect | shared | indirect
165 * information | tree | tree | data | data
166 * --------------------+--------+----------+--------+----------
167 * parent logical | y | - | - | -
168 * key to resolve | - | y | y | y
169 * tree block logical | - | - | - | -
170 * root for resolving | y | y | y | y
171 *
172 * - column 1: we've the parent -> done
173 * - column 2, 3, 4: we use the key to find the parent
174 *
175 * on disk refs (inline or keyed)
176 * ==============================
177 * backref type | shared | indirect | shared | indirect
178 * information | tree | tree | data | data
179 * --------------------+--------+----------+--------+----------
180 * parent logical | y | - | y | -
181 * key to resolve | - | - | - | y
182 * tree block logical | y | y | y | y
183 * root for resolving | - | y | y | y
184 *
185 * - column 1, 3: we've the parent -> done
186 * - column 2: we take the first key from the block to find the parent
187 * (see __add_missing_keys)
188 * - column 4: we use the key to find the parent
189 *
190 * additional information that's available but not required to find the parent
191 * block might help in merging entries to gain some speed.
192 */
193
Jan Schmidt8da6d582011-11-23 18:55:04 +0100194static int __add_prelim_ref(struct list_head *head, u64 root_id,
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200195 struct btrfs_key *key, int level,
Wang Shilong742916b2013-08-06 10:29:54 +0800196 u64 parent, u64 wanted_disk_byte, int count,
197 gfp_t gfp_mask)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100198{
199 struct __prelim_ref *ref;
200
Liu Bo48ec4732013-10-30 13:25:24 +0800201 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
202 return 0;
203
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800204 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100205 if (!ref)
206 return -ENOMEM;
207
208 ref->root_id = root_id;
Filipe Mananad6589102015-07-29 17:21:17 +0100209 if (key) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200210 ref->key_for_search = *key;
Filipe Mananad6589102015-07-29 17:21:17 +0100211 /*
212 * We can often find data backrefs with an offset that is too
213 * large (>= LLONG_MAX, maximum allowed file offset) due to
214 * underflows when subtracting a file's offset with the data
215 * offset of its corresponding extent data item. This can
216 * happen for example in the clone ioctl.
217 * So if we detect such case we set the search key's offset to
218 * zero to make sure we will find the matching file extent item
219 * at add_all_parents(), otherwise we will miss it because the
220 * offset taken form the backref is much larger then the offset
221 * of the file extent item. This can make us scan a very large
222 * number of file extent items, but at least it will not make
223 * us miss any.
224 * This is an ugly workaround for a behaviour that should have
225 * never existed, but it does and a fix for the clone ioctl
226 * would touch a lot of places, cause backwards incompatibility
227 * and would not fix the problem for extents cloned with older
228 * kernels.
229 */
230 if (ref->key_for_search.type == BTRFS_EXTENT_DATA_KEY &&
231 ref->key_for_search.offset >= LLONG_MAX)
232 ref->key_for_search.offset = 0;
233 } else {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200234 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
Filipe Mananad6589102015-07-29 17:21:17 +0100235 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100236
Jan Schmidt33019582012-05-30 18:05:21 +0200237 ref->inode_list = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100238 ref->level = level;
239 ref->count = count;
240 ref->parent = parent;
241 ref->wanted_disk_byte = wanted_disk_byte;
242 list_add_tail(&ref->list, head);
243
244 return 0;
245}
246
247static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500248 struct ulist *parents, struct __prelim_ref *ref,
Josef Bacik44853862014-03-19 13:35:14 -0400249 int level, u64 time_seq, const u64 *extent_item_pos,
250 u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100251{
Alexander Block69bca402012-06-19 07:42:26 -0600252 int ret = 0;
253 int slot;
254 struct extent_buffer *eb;
255 struct btrfs_key key;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500256 struct btrfs_key *key_for_search = &ref->key_for_search;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100257 struct btrfs_file_extent_item *fi;
Josef Baciked8c4912013-07-05 14:03:47 -0400258 struct extent_inode_elem *eie = NULL, *old = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100259 u64 disk_byte;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500260 u64 wanted_disk_byte = ref->wanted_disk_byte;
261 u64 count = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100262
Alexander Block69bca402012-06-19 07:42:26 -0600263 if (level != 0) {
264 eb = path->nodes[level];
265 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
Jan Schmidt33019582012-05-30 18:05:21 +0200266 if (ret < 0)
267 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100268 return 0;
Alexander Block69bca402012-06-19 07:42:26 -0600269 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100270
271 /*
Alexander Block69bca402012-06-19 07:42:26 -0600272 * We normally enter this function with the path already pointing to
273 * the first item to check. But sometimes, we may enter it with
274 * slot==nritems. In that case, go to the next leaf before we continue.
Jan Schmidt8da6d582011-11-23 18:55:04 +0100275 */
Qu Wenruo21633fc2015-04-16 14:54:50 +0800276 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
277 if (time_seq == (u64)-1)
278 ret = btrfs_next_leaf(root, path);
279 else
280 ret = btrfs_next_old_leaf(root, path, time_seq);
281 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100282
Josef Bacik44853862014-03-19 13:35:14 -0400283 while (!ret && count < total_refs) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100284 eb = path->nodes[0];
Alexander Block69bca402012-06-19 07:42:26 -0600285 slot = path->slots[0];
286
287 btrfs_item_key_to_cpu(eb, &key, slot);
288
289 if (key.objectid != key_for_search->objectid ||
290 key.type != BTRFS_EXTENT_DATA_KEY)
291 break;
292
293 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
294 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
295
296 if (disk_byte == wanted_disk_byte) {
297 eie = NULL;
Josef Baciked8c4912013-07-05 14:03:47 -0400298 old = NULL;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500299 count++;
Alexander Block69bca402012-06-19 07:42:26 -0600300 if (extent_item_pos) {
301 ret = check_extent_in_eb(&key, eb, fi,
302 *extent_item_pos,
303 &eie);
304 if (ret < 0)
305 break;
306 }
Josef Baciked8c4912013-07-05 14:03:47 -0400307 if (ret > 0)
308 goto next;
Takashi Iwai4eb1f662014-07-28 10:57:04 +0200309 ret = ulist_add_merge_ptr(parents, eb->start,
310 eie, (void **)&old, GFP_NOFS);
Josef Baciked8c4912013-07-05 14:03:47 -0400311 if (ret < 0)
312 break;
313 if (!ret && extent_item_pos) {
314 while (old->next)
315 old = old->next;
316 old->next = eie;
Alexander Block69bca402012-06-19 07:42:26 -0600317 }
Wang Shilongf05c4742014-01-28 19:13:38 +0800318 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100319 }
Josef Baciked8c4912013-07-05 14:03:47 -0400320next:
Qu Wenruo21633fc2015-04-16 14:54:50 +0800321 if (time_seq == (u64)-1)
322 ret = btrfs_next_item(root, path);
323 else
324 ret = btrfs_next_old_item(root, path, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100325 }
326
Alexander Block69bca402012-06-19 07:42:26 -0600327 if (ret > 0)
328 ret = 0;
Wang Shilongf05c4742014-01-28 19:13:38 +0800329 else if (ret < 0)
330 free_inode_elem_list(eie);
Alexander Block69bca402012-06-19 07:42:26 -0600331 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100332}
333
334/*
335 * resolve an indirect backref in the form (root_id, key, level)
336 * to a logical address
337 */
338static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400339 struct btrfs_path *path, u64 time_seq,
340 struct __prelim_ref *ref,
341 struct ulist *parents,
Josef Bacik44853862014-03-19 13:35:14 -0400342 const u64 *extent_item_pos, u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100343{
Jan Schmidt8da6d582011-11-23 18:55:04 +0100344 struct btrfs_root *root;
345 struct btrfs_key root_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100346 struct extent_buffer *eb;
347 int ret = 0;
348 int root_level;
349 int level = ref->level;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800350 int index;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100351
Jan Schmidt8da6d582011-11-23 18:55:04 +0100352 root_key.objectid = ref->root_id;
353 root_key.type = BTRFS_ROOT_ITEM_KEY;
354 root_key.offset = (u64)-1;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800355
356 index = srcu_read_lock(&fs_info->subvol_srcu);
357
Josef Bacik2d9e9772015-11-05 14:37:58 -0800358 root = btrfs_get_fs_root(fs_info, &root_key, false);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100359 if (IS_ERR(root)) {
Wang Shilong538f72cd2014-01-23 13:47:48 +0800360 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100361 ret = PTR_ERR(root);
362 goto out;
363 }
364
Josef Bacikd9ee5222015-10-05 10:35:29 -0400365 if (btrfs_test_is_dummy_root(root)) {
366 srcu_read_unlock(&fs_info->subvol_srcu, index);
367 ret = -ENOENT;
368 goto out;
369 }
370
Josef Bacik9e351cc2014-03-13 15:42:13 -0400371 if (path->search_commit_root)
372 root_level = btrfs_header_level(root->commit_root);
Qu Wenruo21633fc2015-04-16 14:54:50 +0800373 else if (time_seq == (u64)-1)
374 root_level = btrfs_header_level(root->node);
Josef Bacik9e351cc2014-03-13 15:42:13 -0400375 else
376 root_level = btrfs_old_root_level(root, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100377
Wang Shilong538f72cd2014-01-23 13:47:48 +0800378 if (root_level + 1 == level) {
379 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100380 goto out;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800381 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100382
383 path->lowest_level = level;
Qu Wenruo21633fc2015-04-16 14:54:50 +0800384 if (time_seq == (u64)-1)
385 ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
386 0, 0);
387 else
388 ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
389 time_seq);
Wang Shilong538f72cd2014-01-23 13:47:48 +0800390
391 /* root node has been locked, we can release @subvol_srcu safely here */
392 srcu_read_unlock(&fs_info->subvol_srcu, index);
393
Jan Schmidt8da6d582011-11-23 18:55:04 +0100394 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
395 "%d for key (%llu %u %llu)\n",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +0200396 ref->root_id, level, ref->count, ret,
397 ref->key_for_search.objectid, ref->key_for_search.type,
398 ref->key_for_search.offset);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100399 if (ret < 0)
400 goto out;
401
402 eb = path->nodes[level];
Jan Schmidt93454572012-06-27 15:23:09 +0200403 while (!eb) {
Dulshani Gunawardhanafae7f212013-10-31 10:30:08 +0530404 if (WARN_ON(!level)) {
Jan Schmidt93454572012-06-27 15:23:09 +0200405 ret = 1;
406 goto out;
407 }
408 level--;
409 eb = path->nodes[level];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100410 }
411
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500412 ret = add_all_parents(root, path, parents, ref, level, time_seq,
Josef Bacik44853862014-03-19 13:35:14 -0400413 extent_item_pos, total_refs);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100414out:
Josef Bacikda61d312013-06-12 16:20:08 -0400415 path->lowest_level = 0;
416 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100417 return ret;
418}
419
420/*
421 * resolve all indirect backrefs from the list
422 */
423static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400424 struct btrfs_path *path, u64 time_seq,
Jan Schmidt976b1902012-05-17 16:43:03 +0200425 struct list_head *head,
Josef Bacikdc046b12014-09-10 16:20:45 -0400426 const u64 *extent_item_pos, u64 total_refs,
427 u64 root_objectid)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100428{
429 int err;
430 int ret = 0;
431 struct __prelim_ref *ref;
432 struct __prelim_ref *ref_safe;
433 struct __prelim_ref *new_ref;
434 struct ulist *parents;
435 struct ulist_node *node;
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200436 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100437
438 parents = ulist_alloc(GFP_NOFS);
439 if (!parents)
440 return -ENOMEM;
441
442 /*
443 * _safe allows us to insert directly after the current item without
444 * iterating over the newly inserted items.
445 * we're also allowed to re-assign ref during iteration.
446 */
447 list_for_each_entry_safe(ref, ref_safe, head, list) {
448 if (ref->parent) /* already direct */
449 continue;
450 if (ref->count == 0)
451 continue;
Josef Bacikdc046b12014-09-10 16:20:45 -0400452 if (root_objectid && ref->root_id != root_objectid) {
453 ret = BACKREF_FOUND_SHARED;
454 goto out;
455 }
Josef Bacikda61d312013-06-12 16:20:08 -0400456 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
Josef Bacik44853862014-03-19 13:35:14 -0400457 parents, extent_item_pos,
458 total_refs);
Wang Shilong95def2ed2014-01-23 13:47:49 +0800459 /*
460 * we can only tolerate ENOENT,otherwise,we should catch error
461 * and return directly.
462 */
463 if (err == -ENOENT) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100464 continue;
Wang Shilong95def2ed2014-01-23 13:47:49 +0800465 } else if (err) {
466 ret = err;
467 goto out;
468 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100469
470 /* we put the first parent into the ref at hand */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200471 ULIST_ITER_INIT(&uiter);
472 node = ulist_next(parents, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100473 ref->parent = node ? node->val : 0;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600474 ref->inode_list = node ?
Stefan Behrens35a36212013-08-14 18:12:25 +0200475 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100476
477 /* additional parents require new refs being added here */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200478 while ((node = ulist_next(parents, &uiter))) {
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800479 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
480 GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100481 if (!new_ref) {
482 ret = -ENOMEM;
Wang Shilonge36902d2013-04-15 10:26:38 +0000483 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100484 }
485 memcpy(new_ref, ref, sizeof(*ref));
486 new_ref->parent = node->val;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600487 new_ref->inode_list = (struct extent_inode_elem *)
488 (uintptr_t)node->aux;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100489 list_add(&new_ref->list, &ref->list);
490 }
491 ulist_reinit(parents);
492 }
Wang Shilonge36902d2013-04-15 10:26:38 +0000493out:
Jan Schmidt8da6d582011-11-23 18:55:04 +0100494 ulist_free(parents);
495 return ret;
496}
497
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200498static inline int ref_for_same_block(struct __prelim_ref *ref1,
499 struct __prelim_ref *ref2)
500{
501 if (ref1->level != ref2->level)
502 return 0;
503 if (ref1->root_id != ref2->root_id)
504 return 0;
505 if (ref1->key_for_search.type != ref2->key_for_search.type)
506 return 0;
507 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
508 return 0;
509 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
510 return 0;
511 if (ref1->parent != ref2->parent)
512 return 0;
513
514 return 1;
515}
516
517/*
518 * read tree blocks and add keys where required.
519 */
520static int __add_missing_keys(struct btrfs_fs_info *fs_info,
521 struct list_head *head)
522{
523 struct list_head *pos;
524 struct extent_buffer *eb;
525
526 list_for_each(pos, head) {
527 struct __prelim_ref *ref;
528 ref = list_entry(pos, struct __prelim_ref, list);
529
530 if (ref->parent)
531 continue;
532 if (ref->key_for_search.type)
533 continue;
534 BUG_ON(!ref->wanted_disk_byte);
535 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
David Sterbace86cd52014-06-15 01:07:32 +0200536 0);
Liu Bo64c043d2015-05-25 17:30:15 +0800537 if (IS_ERR(eb)) {
538 return PTR_ERR(eb);
539 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -0400540 free_extent_buffer(eb);
541 return -EIO;
542 }
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200543 btrfs_tree_read_lock(eb);
544 if (btrfs_header_level(eb) == 0)
545 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
546 else
547 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
548 btrfs_tree_read_unlock(eb);
549 free_extent_buffer(eb);
550 }
551 return 0;
552}
553
Jan Schmidt8da6d582011-11-23 18:55:04 +0100554/*
Qu Wenruo00db6462015-04-01 14:39:06 +0800555 * merge backrefs and adjust counts accordingly
Jan Schmidt8da6d582011-11-23 18:55:04 +0100556 *
557 * mode = 1: merge identical keys, if key is set
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200558 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
559 * additionally, we could even add a key range for the blocks we
560 * looked into to merge even more (-> replace unresolved refs by those
561 * having a parent).
Jan Schmidt8da6d582011-11-23 18:55:04 +0100562 * mode = 2: merge identical parents
563 */
Wang Shilong692206b2013-04-11 07:08:55 +0000564static void __merge_refs(struct list_head *head, int mode)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100565{
566 struct list_head *pos1;
567
568 list_for_each(pos1, head) {
569 struct list_head *n2;
570 struct list_head *pos2;
571 struct __prelim_ref *ref1;
572
573 ref1 = list_entry(pos1, struct __prelim_ref, list);
574
Jan Schmidt8da6d582011-11-23 18:55:04 +0100575 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
576 pos2 = n2, n2 = pos2->next) {
577 struct __prelim_ref *ref2;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200578 struct __prelim_ref *xchg;
Alexander Block3ef59692012-11-08 21:27:24 +0000579 struct extent_inode_elem *eie;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100580
581 ref2 = list_entry(pos2, struct __prelim_ref, list);
582
Qu Wenruo00db6462015-04-01 14:39:06 +0800583 if (!ref_for_same_block(ref1, ref2))
584 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100585 if (mode == 1) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200586 if (!ref1->parent && ref2->parent) {
587 xchg = ref1;
588 ref1 = ref2;
589 ref2 = xchg;
590 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100591 } else {
592 if (ref1->parent != ref2->parent)
593 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100594 }
Alexander Block3ef59692012-11-08 21:27:24 +0000595
596 eie = ref1->inode_list;
597 while (eie && eie->next)
598 eie = eie->next;
599 if (eie)
600 eie->next = ref2->inode_list;
601 else
602 ref1->inode_list = ref2->inode_list;
603 ref1->count += ref2->count;
604
Jan Schmidt8da6d582011-11-23 18:55:04 +0100605 list_del(&ref2->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800606 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100607 }
608
609 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100610}
611
612/*
613 * add all currently queued delayed refs from this head whose seq nr is
614 * smaller or equal that seq to the list
615 */
616static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
Josef Bacikdc046b12014-09-10 16:20:45 -0400617 struct list_head *prefs, u64 *total_refs,
618 u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100619{
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800620 struct btrfs_delayed_ref_node *node;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100621 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200622 struct btrfs_key key;
623 struct btrfs_key op_key = {0};
Jan Schmidt8da6d582011-11-23 18:55:04 +0100624 int sgn;
Jan Schmidtb1375d62012-01-26 15:01:11 -0500625 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100626
627 if (extent_op && extent_op->update_key)
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200628 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100629
Josef Bacikd7df2c72014-01-23 09:21:38 -0500630 spin_lock(&head->lock);
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800631 list_for_each_entry(node, &head->ref_list, list) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100632 if (node->seq > seq)
633 continue;
634
635 switch (node->action) {
636 case BTRFS_ADD_DELAYED_EXTENT:
637 case BTRFS_UPDATE_DELAYED_HEAD:
638 WARN_ON(1);
639 continue;
640 case BTRFS_ADD_DELAYED_REF:
641 sgn = 1;
642 break;
643 case BTRFS_DROP_DELAYED_REF:
644 sgn = -1;
645 break;
646 default:
647 BUG_ON(1);
648 }
Josef Bacik44853862014-03-19 13:35:14 -0400649 *total_refs += (node->ref_mod * sgn);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100650 switch (node->type) {
651 case BTRFS_TREE_BLOCK_REF_KEY: {
652 struct btrfs_delayed_tree_ref *ref;
653
654 ref = btrfs_delayed_node_to_tree_ref(node);
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200655 ret = __add_prelim_ref(prefs, ref->root, &op_key,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100656 ref->level + 1, 0, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800657 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100658 break;
659 }
660 case BTRFS_SHARED_BLOCK_REF_KEY: {
661 struct btrfs_delayed_tree_ref *ref;
662
663 ref = btrfs_delayed_node_to_tree_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800664 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100665 ref->level + 1, ref->parent,
666 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800667 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100668 break;
669 }
670 case BTRFS_EXTENT_DATA_REF_KEY: {
671 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100672 ref = btrfs_delayed_node_to_data_ref(node);
673
674 key.objectid = ref->objectid;
675 key.type = BTRFS_EXTENT_DATA_KEY;
676 key.offset = ref->offset;
Josef Bacikdc046b12014-09-10 16:20:45 -0400677
678 /*
679 * Found a inum that doesn't match our known inum, we
680 * know it's shared.
681 */
682 if (inum && ref->objectid != inum) {
683 ret = BACKREF_FOUND_SHARED;
684 break;
685 }
686
Jan Schmidt8da6d582011-11-23 18:55:04 +0100687 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
688 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800689 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100690 break;
691 }
692 case BTRFS_SHARED_DATA_REF_KEY: {
693 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100694
695 ref = btrfs_delayed_node_to_data_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800696 ret = __add_prelim_ref(prefs, 0, NULL, 0,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100697 ref->parent, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800698 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100699 break;
700 }
701 default:
702 WARN_ON(1);
703 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000704 if (ret)
Josef Bacikd7df2c72014-01-23 09:21:38 -0500705 break;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100706 }
Josef Bacikd7df2c72014-01-23 09:21:38 -0500707 spin_unlock(&head->lock);
708 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100709}
710
711/*
712 * add all inline backrefs for bytenr to the list
713 */
714static int __add_inline_refs(struct btrfs_fs_info *fs_info,
715 struct btrfs_path *path, u64 bytenr,
Josef Bacik44853862014-03-19 13:35:14 -0400716 int *info_level, struct list_head *prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -0400717 u64 *total_refs, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100718{
Jan Schmidtb1375d62012-01-26 15:01:11 -0500719 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100720 int slot;
721 struct extent_buffer *leaf;
722 struct btrfs_key key;
Josef Bacik261c84b2013-06-28 13:11:22 -0400723 struct btrfs_key found_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100724 unsigned long ptr;
725 unsigned long end;
726 struct btrfs_extent_item *ei;
727 u64 flags;
728 u64 item_size;
729
730 /*
731 * enumerate all inline refs
732 */
733 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +0200734 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100735
736 item_size = btrfs_item_size_nr(leaf, slot);
737 BUG_ON(item_size < sizeof(*ei));
738
739 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
740 flags = btrfs_extent_flags(leaf, ei);
Josef Bacik44853862014-03-19 13:35:14 -0400741 *total_refs += btrfs_extent_refs(leaf, ei);
Josef Bacik261c84b2013-06-28 13:11:22 -0400742 btrfs_item_key_to_cpu(leaf, &found_key, slot);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100743
744 ptr = (unsigned long)(ei + 1);
745 end = (unsigned long)ei + item_size;
746
Josef Bacik261c84b2013-06-28 13:11:22 -0400747 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
748 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100749 struct btrfs_tree_block_info *info;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100750
751 info = (struct btrfs_tree_block_info *)ptr;
752 *info_level = btrfs_tree_block_level(leaf, info);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100753 ptr += sizeof(struct btrfs_tree_block_info);
754 BUG_ON(ptr > end);
Josef Bacik261c84b2013-06-28 13:11:22 -0400755 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
756 *info_level = found_key.offset;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100757 } else {
758 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
759 }
760
761 while (ptr < end) {
762 struct btrfs_extent_inline_ref *iref;
763 u64 offset;
764 int type;
765
766 iref = (struct btrfs_extent_inline_ref *)ptr;
767 type = btrfs_extent_inline_ref_type(leaf, iref);
768 offset = btrfs_extent_inline_ref_offset(leaf, iref);
769
770 switch (type) {
771 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200772 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100773 *info_level + 1, offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800774 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100775 break;
776 case BTRFS_SHARED_DATA_REF_KEY: {
777 struct btrfs_shared_data_ref *sdref;
778 int count;
779
780 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
781 count = btrfs_shared_data_ref_count(leaf, sdref);
782 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800783 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100784 break;
785 }
786 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200787 ret = __add_prelim_ref(prefs, offset, NULL,
788 *info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800789 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100790 break;
791 case BTRFS_EXTENT_DATA_REF_KEY: {
792 struct btrfs_extent_data_ref *dref;
793 int count;
794 u64 root;
795
796 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
797 count = btrfs_extent_data_ref_count(leaf, dref);
798 key.objectid = btrfs_extent_data_ref_objectid(leaf,
799 dref);
800 key.type = BTRFS_EXTENT_DATA_KEY;
801 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -0400802
803 if (inum && key.objectid != inum) {
804 ret = BACKREF_FOUND_SHARED;
805 break;
806 }
807
Jan Schmidt8da6d582011-11-23 18:55:04 +0100808 root = btrfs_extent_data_ref_root(leaf, dref);
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200809 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800810 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100811 break;
812 }
813 default:
814 WARN_ON(1);
815 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000816 if (ret)
817 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100818 ptr += btrfs_extent_inline_ref_size(type);
819 }
820
821 return 0;
822}
823
824/*
825 * add all non-inline backrefs for bytenr to the list
826 */
827static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
828 struct btrfs_path *path, u64 bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -0400829 int info_level, struct list_head *prefs, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100830{
831 struct btrfs_root *extent_root = fs_info->extent_root;
832 int ret;
833 int slot;
834 struct extent_buffer *leaf;
835 struct btrfs_key key;
836
837 while (1) {
838 ret = btrfs_next_item(extent_root, path);
839 if (ret < 0)
840 break;
841 if (ret) {
842 ret = 0;
843 break;
844 }
845
846 slot = path->slots[0];
847 leaf = path->nodes[0];
848 btrfs_item_key_to_cpu(leaf, &key, slot);
849
850 if (key.objectid != bytenr)
851 break;
852 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
853 continue;
854 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
855 break;
856
857 switch (key.type) {
858 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200859 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100860 info_level + 1, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800861 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100862 break;
863 case BTRFS_SHARED_DATA_REF_KEY: {
864 struct btrfs_shared_data_ref *sdref;
865 int count;
866
867 sdref = btrfs_item_ptr(leaf, slot,
868 struct btrfs_shared_data_ref);
869 count = btrfs_shared_data_ref_count(leaf, sdref);
870 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +0800871 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100872 break;
873 }
874 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200875 ret = __add_prelim_ref(prefs, key.offset, NULL,
876 info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800877 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100878 break;
879 case BTRFS_EXTENT_DATA_REF_KEY: {
880 struct btrfs_extent_data_ref *dref;
881 int count;
882 u64 root;
883
884 dref = btrfs_item_ptr(leaf, slot,
885 struct btrfs_extent_data_ref);
886 count = btrfs_extent_data_ref_count(leaf, dref);
887 key.objectid = btrfs_extent_data_ref_objectid(leaf,
888 dref);
889 key.type = BTRFS_EXTENT_DATA_KEY;
890 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -0400891
892 if (inum && key.objectid != inum) {
893 ret = BACKREF_FOUND_SHARED;
894 break;
895 }
896
Jan Schmidt8da6d582011-11-23 18:55:04 +0100897 root = btrfs_extent_data_ref_root(leaf, dref);
898 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +0800899 bytenr, count, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100900 break;
901 }
902 default:
903 WARN_ON(1);
904 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000905 if (ret)
906 return ret;
907
Jan Schmidt8da6d582011-11-23 18:55:04 +0100908 }
909
910 return ret;
911}
912
913/*
914 * this adds all existing backrefs (inline backrefs, backrefs and delayed
915 * refs) for the given bytenr to the refs list, merges duplicates and resolves
916 * indirect refs to their parent bytenr.
917 * When roots are found, they're added to the roots list
918 *
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -0700919 * NOTE: This can return values > 0
920 *
Qu Wenruo21633fc2015-04-16 14:54:50 +0800921 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
922 * much like trans == NULL case, the difference only lies in it will not
923 * commit root.
924 * The special case is for qgroup to search roots in commit_transaction().
925 *
Jan Schmidt8da6d582011-11-23 18:55:04 +0100926 * FIXME some caching might speed things up
927 */
928static int find_parent_nodes(struct btrfs_trans_handle *trans,
929 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +0200930 u64 time_seq, struct ulist *refs,
Josef Bacikdc046b12014-09-10 16:20:45 -0400931 struct ulist *roots, const u64 *extent_item_pos,
932 u64 root_objectid, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100933{
934 struct btrfs_key key;
935 struct btrfs_path *path;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100936 struct btrfs_delayed_ref_root *delayed_refs = NULL;
Li Zefand3b01062012-03-03 07:41:15 -0500937 struct btrfs_delayed_ref_head *head;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100938 int info_level = 0;
939 int ret;
940 struct list_head prefs_delayed;
941 struct list_head prefs;
942 struct __prelim_ref *ref;
Wang Shilongf05c4742014-01-28 19:13:38 +0800943 struct extent_inode_elem *eie = NULL;
Josef Bacik44853862014-03-19 13:35:14 -0400944 u64 total_refs = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100945
946 INIT_LIST_HEAD(&prefs);
947 INIT_LIST_HEAD(&prefs_delayed);
948
949 key.objectid = bytenr;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100950 key.offset = (u64)-1;
Josef Bacik261c84b2013-06-28 13:11:22 -0400951 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
952 key.type = BTRFS_METADATA_ITEM_KEY;
953 else
954 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100955
956 path = btrfs_alloc_path();
957 if (!path)
958 return -ENOMEM;
Wang Shilonge84752d2014-02-13 11:19:47 +0800959 if (!trans) {
Josef Bacikda61d312013-06-12 16:20:08 -0400960 path->search_commit_root = 1;
Wang Shilonge84752d2014-02-13 11:19:47 +0800961 path->skip_locking = 1;
962 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100963
Qu Wenruo21633fc2015-04-16 14:54:50 +0800964 if (time_seq == (u64)-1)
965 path->skip_locking = 1;
966
Jan Schmidt8da6d582011-11-23 18:55:04 +0100967 /*
968 * grab both a lock on the path and a lock on the delayed ref head.
969 * We need both to get a consistent picture of how the refs look
970 * at a specified point in time
971 */
972again:
Li Zefand3b01062012-03-03 07:41:15 -0500973 head = NULL;
974
Jan Schmidt8da6d582011-11-23 18:55:04 +0100975 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
976 if (ret < 0)
977 goto out;
978 BUG_ON(ret == 0);
979
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400980#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
Qu Wenruo21633fc2015-04-16 14:54:50 +0800981 if (trans && likely(trans->type != __TRANS_DUMMY) &&
982 time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400983#else
Qu Wenruo21633fc2015-04-16 14:54:50 +0800984 if (trans && time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -0400985#endif
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100986 /*
987 * look if there are updates for this ref queued and lock the
988 * head
989 */
990 delayed_refs = &trans->transaction->delayed_refs;
991 spin_lock(&delayed_refs->lock);
992 head = btrfs_find_delayed_ref_head(trans, bytenr);
993 if (head) {
994 if (!mutex_trylock(&head->mutex)) {
995 atomic_inc(&head->node.refs);
996 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100997
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100998 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100999
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001000 /*
1001 * Mutex was contended, block until it's
1002 * released and try again
1003 */
1004 mutex_lock(&head->mutex);
1005 mutex_unlock(&head->mutex);
1006 btrfs_put_delayed_ref(&head->node);
1007 goto again;
1008 }
Josef Bacikd7df2c72014-01-23 09:21:38 -05001009 spin_unlock(&delayed_refs->lock);
Jan Schmidt097b8a72012-06-21 11:08:04 +02001010 ret = __add_delayed_refs(head, time_seq,
Josef Bacikdc046b12014-09-10 16:20:45 -04001011 &prefs_delayed, &total_refs,
1012 inum);
Jan Schmidt155725c2012-06-22 14:01:00 +02001013 mutex_unlock(&head->mutex);
Josef Bacikd7df2c72014-01-23 09:21:38 -05001014 if (ret)
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001015 goto out;
Josef Bacikd7df2c72014-01-23 09:21:38 -05001016 } else {
1017 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001018 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001019 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001020
1021 if (path->slots[0]) {
1022 struct extent_buffer *leaf;
1023 int slot;
1024
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001025 path->slots[0]--;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001026 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001027 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +01001028 btrfs_item_key_to_cpu(leaf, &key, slot);
1029 if (key.objectid == bytenr &&
Josef Bacik261c84b2013-06-28 13:11:22 -04001030 (key.type == BTRFS_EXTENT_ITEM_KEY ||
1031 key.type == BTRFS_METADATA_ITEM_KEY)) {
Jan Schmidt8da6d582011-11-23 18:55:04 +01001032 ret = __add_inline_refs(fs_info, path, bytenr,
Josef Bacik44853862014-03-19 13:35:14 -04001033 &info_level, &prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001034 &total_refs, inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001035 if (ret)
1036 goto out;
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001037 ret = __add_keyed_refs(fs_info, path, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001038 info_level, &prefs, inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001039 if (ret)
1040 goto out;
1041 }
1042 }
1043 btrfs_release_path(path);
1044
Jan Schmidt8da6d582011-11-23 18:55:04 +01001045 list_splice_init(&prefs_delayed, &prefs);
1046
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001047 ret = __add_missing_keys(fs_info, &prefs);
1048 if (ret)
1049 goto out;
1050
Wang Shilong692206b2013-04-11 07:08:55 +00001051 __merge_refs(&prefs, 1);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001052
Josef Bacikda61d312013-06-12 16:20:08 -04001053 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001054 extent_item_pos, total_refs,
1055 root_objectid);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001056 if (ret)
1057 goto out;
1058
Wang Shilong692206b2013-04-11 07:08:55 +00001059 __merge_refs(&prefs, 2);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001060
1061 while (!list_empty(&prefs)) {
1062 ref = list_first_entry(&prefs, struct __prelim_ref, list);
Julia Lawall6c1500f2012-11-03 20:30:18 +00001063 WARN_ON(ref->count < 0);
Wang Shilong98cfee212014-02-01 00:42:05 +08001064 if (roots && ref->count && ref->root_id && ref->parent == 0) {
Josef Bacikdc046b12014-09-10 16:20:45 -04001065 if (root_objectid && ref->root_id != root_objectid) {
1066 ret = BACKREF_FOUND_SHARED;
1067 goto out;
1068 }
1069
Jan Schmidt8da6d582011-11-23 18:55:04 +01001070 /* no parent == root of tree */
1071 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001072 if (ret < 0)
1073 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001074 }
1075 if (ref->count && ref->parent) {
Josef Bacik8a564572014-06-05 16:08:45 -04001076 if (extent_item_pos && !ref->inode_list &&
1077 ref->level == 0) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001078 struct extent_buffer *eb;
David Sterba707e8a02014-06-04 19:22:26 +02001079
Jan Schmidt976b1902012-05-17 16:43:03 +02001080 eb = read_tree_block(fs_info->extent_root,
David Sterbace86cd52014-06-15 01:07:32 +02001081 ref->parent, 0);
Liu Bo64c043d2015-05-25 17:30:15 +08001082 if (IS_ERR(eb)) {
1083 ret = PTR_ERR(eb);
1084 goto out;
1085 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -04001086 free_extent_buffer(eb);
Wang Shilongc16c2e22013-05-08 08:10:25 +00001087 ret = -EIO;
1088 goto out;
Josef Bacik416bc652013-04-23 14:17:42 -04001089 }
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001090 btrfs_tree_read_lock(eb);
1091 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidt976b1902012-05-17 16:43:03 +02001092 ret = find_extent_in_eb(eb, bytenr,
1093 *extent_item_pos, &eie);
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001094 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidt976b1902012-05-17 16:43:03 +02001095 free_extent_buffer(eb);
Filipe David Borba Mananaf5929cd2013-07-31 00:26:35 +01001096 if (ret < 0)
1097 goto out;
1098 ref->inode_list = eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001099 }
Takashi Iwai4eb1f662014-07-28 10:57:04 +02001100 ret = ulist_add_merge_ptr(refs, ref->parent,
1101 ref->inode_list,
1102 (void **)&eie, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001103 if (ret < 0)
1104 goto out;
Jan Schmidt33019582012-05-30 18:05:21 +02001105 if (!ret && extent_item_pos) {
1106 /*
1107 * we've recorded that parent, so we must extend
1108 * its inode list here
1109 */
1110 BUG_ON(!eie);
1111 while (eie->next)
1112 eie = eie->next;
1113 eie->next = ref->inode_list;
1114 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001115 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001116 }
Wang Shilonga4fdb612013-08-08 13:04:17 +08001117 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 }
1120
1121out:
Jan Schmidt8da6d582011-11-23 18:55:04 +01001122 btrfs_free_path(path);
1123 while (!list_empty(&prefs)) {
1124 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1125 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001126 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001127 }
1128 while (!list_empty(&prefs_delayed)) {
1129 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1130 list);
1131 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001132 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001133 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001134 if (ret < 0)
1135 free_inode_elem_list(eie);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001136 return ret;
1137}
1138
Jan Schmidt976b1902012-05-17 16:43:03 +02001139static void free_leaf_list(struct ulist *blocks)
1140{
1141 struct ulist_node *node = NULL;
1142 struct extent_inode_elem *eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001143 struct ulist_iterator uiter;
1144
1145 ULIST_ITER_INIT(&uiter);
1146 while ((node = ulist_next(blocks, &uiter))) {
1147 if (!node->aux)
1148 continue;
Jan Schmidt995e01b2012-08-13 02:52:38 -06001149 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
Wang Shilongf05c4742014-01-28 19:13:38 +08001150 free_inode_elem_list(eie);
Jan Schmidt976b1902012-05-17 16:43:03 +02001151 node->aux = 0;
1152 }
1153
1154 ulist_free(blocks);
1155}
1156
Jan Schmidt8da6d582011-11-23 18:55:04 +01001157/*
1158 * Finds all leafs with a reference to the specified combination of bytenr and
1159 * offset. key_list_head will point to a list of corresponding keys (caller must
1160 * free each list element). The leafs will be stored in the leafs ulist, which
1161 * must be freed with ulist_free.
1162 *
1163 * returns 0 on success, <0 on error
1164 */
1165static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1166 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001167 u64 time_seq, struct ulist **leafs,
Jan Schmidt976b1902012-05-17 16:43:03 +02001168 const u64 *extent_item_pos)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001169{
Jan Schmidt8da6d582011-11-23 18:55:04 +01001170 int ret;
1171
Jan Schmidt8da6d582011-11-23 18:55:04 +01001172 *leafs = ulist_alloc(GFP_NOFS);
Wang Shilong98cfee212014-02-01 00:42:05 +08001173 if (!*leafs)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001174 return -ENOMEM;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001175
Jan Schmidt097b8a72012-06-21 11:08:04 +02001176 ret = find_parent_nodes(trans, fs_info, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001177 time_seq, *leafs, NULL, extent_item_pos, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001178 if (ret < 0 && ret != -ENOENT) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001179 free_leaf_list(*leafs);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001180 return ret;
1181 }
1182
1183 return 0;
1184}
1185
1186/*
1187 * walk all backrefs for a given extent to find all roots that reference this
1188 * extent. Walking a backref means finding all extents that reference this
1189 * extent and in turn walk the backrefs of those, too. Naturally this is a
1190 * recursive process, but here it is implemented in an iterative fashion: We
1191 * find all referencing extents for the extent in question and put them on a
1192 * list. In turn, we find all referencing extents for those, further appending
1193 * to the list. The way we iterate the list allows adding more elements after
1194 * the current while iterating. The process stops when we reach the end of the
1195 * list. Found roots are added to the roots list.
1196 *
1197 * returns 0 on success, < 0 on error.
1198 */
Josef Bacik9e351cc2014-03-13 15:42:13 -04001199static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1200 struct btrfs_fs_info *fs_info, u64 bytenr,
1201 u64 time_seq, struct ulist **roots)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001202{
1203 struct ulist *tmp;
1204 struct ulist_node *node = NULL;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001205 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001206 int ret;
1207
1208 tmp = ulist_alloc(GFP_NOFS);
1209 if (!tmp)
1210 return -ENOMEM;
1211 *roots = ulist_alloc(GFP_NOFS);
1212 if (!*roots) {
1213 ulist_free(tmp);
1214 return -ENOMEM;
1215 }
1216
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001217 ULIST_ITER_INIT(&uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001218 while (1) {
Jan Schmidt097b8a72012-06-21 11:08:04 +02001219 ret = find_parent_nodes(trans, fs_info, bytenr,
Josef Bacikdc046b12014-09-10 16:20:45 -04001220 time_seq, tmp, *roots, NULL, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001221 if (ret < 0 && ret != -ENOENT) {
1222 ulist_free(tmp);
1223 ulist_free(*roots);
1224 return ret;
1225 }
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001226 node = ulist_next(tmp, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001227 if (!node)
1228 break;
1229 bytenr = node->val;
Wang Shilongbca1a292014-01-26 22:32:18 +08001230 cond_resched();
Jan Schmidt8da6d582011-11-23 18:55:04 +01001231 }
1232
1233 ulist_free(tmp);
1234 return 0;
1235}
1236
Josef Bacik9e351cc2014-03-13 15:42:13 -04001237int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1238 struct btrfs_fs_info *fs_info, u64 bytenr,
1239 u64 time_seq, struct ulist **roots)
1240{
1241 int ret;
1242
1243 if (!trans)
1244 down_read(&fs_info->commit_root_sem);
1245 ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1246 if (!trans)
1247 up_read(&fs_info->commit_root_sem);
1248 return ret;
1249}
1250
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001251/**
1252 * btrfs_check_shared - tell us whether an extent is shared
1253 *
1254 * @trans: optional trans handle
1255 *
1256 * btrfs_check_shared uses the backref walking code but will short
1257 * circuit as soon as it finds a root or inode that doesn't match the
1258 * one passed in. This provides a significant performance benefit for
1259 * callers (such as fiemap) which want to know whether the extent is
1260 * shared but do not need a ref count.
1261 *
1262 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1263 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001264int btrfs_check_shared(struct btrfs_trans_handle *trans,
1265 struct btrfs_fs_info *fs_info, u64 root_objectid,
1266 u64 inum, u64 bytenr)
1267{
1268 struct ulist *tmp = NULL;
1269 struct ulist *roots = NULL;
1270 struct ulist_iterator uiter;
1271 struct ulist_node *node;
David Sterba3284da72015-02-25 15:47:32 +01001272 struct seq_list elem = SEQ_LIST_INIT(elem);
Josef Bacikdc046b12014-09-10 16:20:45 -04001273 int ret = 0;
1274
1275 tmp = ulist_alloc(GFP_NOFS);
1276 roots = ulist_alloc(GFP_NOFS);
1277 if (!tmp || !roots) {
1278 ulist_free(tmp);
1279 ulist_free(roots);
1280 return -ENOMEM;
1281 }
1282
1283 if (trans)
1284 btrfs_get_tree_mod_seq(fs_info, &elem);
1285 else
1286 down_read(&fs_info->commit_root_sem);
1287 ULIST_ITER_INIT(&uiter);
1288 while (1) {
1289 ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
1290 roots, NULL, root_objectid, inum);
1291 if (ret == BACKREF_FOUND_SHARED) {
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001292 /* this is the only condition under which we return 1 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001293 ret = 1;
1294 break;
1295 }
1296 if (ret < 0 && ret != -ENOENT)
1297 break;
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001298 ret = 0;
Josef Bacikdc046b12014-09-10 16:20:45 -04001299 node = ulist_next(tmp, &uiter);
1300 if (!node)
1301 break;
1302 bytenr = node->val;
1303 cond_resched();
1304 }
1305 if (trans)
1306 btrfs_put_tree_mod_seq(fs_info, &elem);
1307 else
1308 up_read(&fs_info->commit_root_sem);
1309 ulist_free(tmp);
1310 ulist_free(roots);
1311 return ret;
1312}
1313
Mark Fashehf1863732012-08-08 11:32:27 -07001314int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1315 u64 start_off, struct btrfs_path *path,
1316 struct btrfs_inode_extref **ret_extref,
1317 u64 *found_off)
1318{
1319 int ret, slot;
1320 struct btrfs_key key;
1321 struct btrfs_key found_key;
1322 struct btrfs_inode_extref *extref;
1323 struct extent_buffer *leaf;
1324 unsigned long ptr;
1325
1326 key.objectid = inode_objectid;
David Sterba962a2982014-06-04 18:41:45 +02001327 key.type = BTRFS_INODE_EXTREF_KEY;
Mark Fashehf1863732012-08-08 11:32:27 -07001328 key.offset = start_off;
1329
1330 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1331 if (ret < 0)
1332 return ret;
1333
1334 while (1) {
1335 leaf = path->nodes[0];
1336 slot = path->slots[0];
1337 if (slot >= btrfs_header_nritems(leaf)) {
1338 /*
1339 * If the item at offset is not found,
1340 * btrfs_search_slot will point us to the slot
1341 * where it should be inserted. In our case
1342 * that will be the slot directly before the
1343 * next INODE_REF_KEY_V2 item. In the case
1344 * that we're pointing to the last slot in a
1345 * leaf, we must move one leaf over.
1346 */
1347 ret = btrfs_next_leaf(root, path);
1348 if (ret) {
1349 if (ret >= 1)
1350 ret = -ENOENT;
1351 break;
1352 }
1353 continue;
1354 }
1355
1356 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1357
1358 /*
1359 * Check that we're still looking at an extended ref key for
1360 * this particular objectid. If we have different
1361 * objectid or type then there are no more to be found
1362 * in the tree and we can exit.
1363 */
1364 ret = -ENOENT;
1365 if (found_key.objectid != inode_objectid)
1366 break;
David Sterba962a2982014-06-04 18:41:45 +02001367 if (found_key.type != BTRFS_INODE_EXTREF_KEY)
Mark Fashehf1863732012-08-08 11:32:27 -07001368 break;
1369
1370 ret = 0;
1371 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1372 extref = (struct btrfs_inode_extref *)ptr;
1373 *ret_extref = extref;
1374 if (found_off)
1375 *found_off = found_key.offset;
1376 break;
1377 }
1378
1379 return ret;
1380}
1381
Eric Sandeen48a3b632013-04-25 20:41:01 +00001382/*
1383 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1384 * Elements of the path are separated by '/' and the path is guaranteed to be
1385 * 0-terminated. the path is only given within the current file system.
1386 * Therefore, it never starts with a '/'. the caller is responsible to provide
1387 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1388 * the start point of the resulting string is returned. this pointer is within
1389 * dest, normally.
1390 * in case the path buffer would overflow, the pointer is decremented further
1391 * as if output was written to the buffer, though no more output is actually
1392 * generated. that way, the caller can determine how much space would be
1393 * required for the path to fit into the buffer. in that case, the returned
1394 * value will be smaller than dest. callers must check this!
1395 */
Jan Schmidt96b5bd72012-10-15 08:30:45 +00001396char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1397 u32 name_len, unsigned long name_off,
1398 struct extent_buffer *eb_in, u64 parent,
1399 char *dest, u32 size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001400{
Jan Schmidta542ad12011-06-13 19:52:59 +02001401 int slot;
1402 u64 next_inum;
1403 int ret;
Gabriel de Perthuis661bec62012-10-10 08:50:47 -06001404 s64 bytes_left = ((s64)size) - 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001405 struct extent_buffer *eb = eb_in;
1406 struct btrfs_key found_key;
Jan Schmidtb916a592012-04-13 12:28:08 +02001407 int leave_spinning = path->leave_spinning;
Mark Fashehd24bec32012-08-08 11:33:54 -07001408 struct btrfs_inode_ref *iref;
Jan Schmidta542ad12011-06-13 19:52:59 +02001409
1410 if (bytes_left >= 0)
1411 dest[bytes_left] = '\0';
1412
Jan Schmidtb916a592012-04-13 12:28:08 +02001413 path->leave_spinning = 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001414 while (1) {
Mark Fashehd24bec32012-08-08 11:33:54 -07001415 bytes_left -= name_len;
Jan Schmidta542ad12011-06-13 19:52:59 +02001416 if (bytes_left >= 0)
1417 read_extent_buffer(eb, dest + bytes_left,
Mark Fashehd24bec32012-08-08 11:33:54 -07001418 name_off, name_len);
Jan Schmidtb916a592012-04-13 12:28:08 +02001419 if (eb != eb_in) {
1420 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001421 free_extent_buffer(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02001422 }
David Sterbac234a242015-01-02 19:03:17 +01001423 ret = btrfs_find_item(fs_root, path, parent, 0,
1424 BTRFS_INODE_REF_KEY, &found_key);
Jan Schmidt8f24b492012-02-08 16:01:01 +01001425 if (ret > 0)
1426 ret = -ENOENT;
Jan Schmidta542ad12011-06-13 19:52:59 +02001427 if (ret)
1428 break;
Mark Fashehd24bec32012-08-08 11:33:54 -07001429
Jan Schmidta542ad12011-06-13 19:52:59 +02001430 next_inum = found_key.offset;
1431
1432 /* regular exit ahead */
1433 if (parent == next_inum)
1434 break;
1435
1436 slot = path->slots[0];
1437 eb = path->nodes[0];
1438 /* make sure we can use eb after releasing the path */
Jan Schmidtb916a592012-04-13 12:28:08 +02001439 if (eb != eb_in) {
Jan Schmidta542ad12011-06-13 19:52:59 +02001440 atomic_inc(&eb->refs);
Jan Schmidtb916a592012-04-13 12:28:08 +02001441 btrfs_tree_read_lock(eb);
1442 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1443 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001444 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001445 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
Mark Fashehd24bec32012-08-08 11:33:54 -07001446
1447 name_len = btrfs_inode_ref_name_len(eb, iref);
1448 name_off = (unsigned long)(iref + 1);
1449
Jan Schmidta542ad12011-06-13 19:52:59 +02001450 parent = next_inum;
1451 --bytes_left;
1452 if (bytes_left >= 0)
1453 dest[bytes_left] = '/';
1454 }
1455
1456 btrfs_release_path(path);
Jan Schmidtb916a592012-04-13 12:28:08 +02001457 path->leave_spinning = leave_spinning;
Jan Schmidta542ad12011-06-13 19:52:59 +02001458
1459 if (ret)
1460 return ERR_PTR(ret);
1461
1462 return dest + bytes_left;
1463}
1464
1465/*
1466 * this makes the path point to (logical EXTENT_ITEM *)
1467 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1468 * tree blocks and <0 on error.
1469 */
1470int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
Liu Bo69917e42012-09-07 20:01:28 -06001471 struct btrfs_path *path, struct btrfs_key *found_key,
1472 u64 *flags_ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001473{
1474 int ret;
1475 u64 flags;
Josef Bacik261c84b2013-06-28 13:11:22 -04001476 u64 size = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001477 u32 item_size;
1478 struct extent_buffer *eb;
1479 struct btrfs_extent_item *ei;
1480 struct btrfs_key key;
1481
Josef Bacik261c84b2013-06-28 13:11:22 -04001482 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1483 key.type = BTRFS_METADATA_ITEM_KEY;
1484 else
1485 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidta542ad12011-06-13 19:52:59 +02001486 key.objectid = logical;
1487 key.offset = (u64)-1;
1488
1489 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1490 if (ret < 0)
1491 return ret;
Jan Schmidta542ad12011-06-13 19:52:59 +02001492
Wang Shilong850a8cd2014-02-06 20:02:29 +08001493 ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1494 if (ret) {
1495 if (ret > 0)
1496 ret = -ENOENT;
1497 return ret;
Josef Bacik580f0a62014-01-23 16:03:45 -05001498 }
Wang Shilong850a8cd2014-02-06 20:02:29 +08001499 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
Josef Bacik261c84b2013-06-28 13:11:22 -04001500 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
David Sterba707e8a02014-06-04 19:22:26 +02001501 size = fs_info->extent_root->nodesize;
Josef Bacik261c84b2013-06-28 13:11:22 -04001502 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1503 size = found_key->offset;
1504
Josef Bacik580f0a62014-01-23 16:03:45 -05001505 if (found_key->objectid > logical ||
Josef Bacik261c84b2013-06-28 13:11:22 -04001506 found_key->objectid + size <= logical) {
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001507 pr_debug("logical %llu is not within any extent\n", logical);
Jan Schmidta542ad12011-06-13 19:52:59 +02001508 return -ENOENT;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001509 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001510
1511 eb = path->nodes[0];
1512 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1513 BUG_ON(item_size < sizeof(*ei));
1514
1515 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1516 flags = btrfs_extent_flags(eb, ei);
1517
Jan Schmidt4692cf52011-12-02 14:56:41 +01001518 pr_debug("logical %llu is at position %llu within the extent (%llu "
1519 "EXTENT_ITEM %llu) flags %#llx size %u\n",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001520 logical, logical - found_key->objectid, found_key->objectid,
1521 found_key->offset, flags, item_size);
Liu Bo69917e42012-09-07 20:01:28 -06001522
1523 WARN_ON(!flags_ret);
1524 if (flags_ret) {
1525 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1526 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1527 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1528 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1529 else
1530 BUG_ON(1);
1531 return 0;
1532 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001533
1534 return -EIO;
1535}
1536
1537/*
1538 * helper function to iterate extent inline refs. ptr must point to a 0 value
1539 * for the first call and may be modified. it is used to track state.
1540 * if more refs exist, 0 is returned and the next call to
1541 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1542 * next ref. after the last ref was processed, 1 is returned.
1543 * returns <0 on error
1544 */
1545static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001546 struct btrfs_key *key,
1547 struct btrfs_extent_item *ei, u32 item_size,
1548 struct btrfs_extent_inline_ref **out_eiref,
1549 int *out_type)
Jan Schmidta542ad12011-06-13 19:52:59 +02001550{
1551 unsigned long end;
1552 u64 flags;
1553 struct btrfs_tree_block_info *info;
1554
1555 if (!*ptr) {
1556 /* first call */
1557 flags = btrfs_extent_flags(eb, ei);
1558 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001559 if (key->type == BTRFS_METADATA_ITEM_KEY) {
1560 /* a skinny metadata extent */
1561 *out_eiref =
1562 (struct btrfs_extent_inline_ref *)(ei + 1);
1563 } else {
1564 WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1565 info = (struct btrfs_tree_block_info *)(ei + 1);
1566 *out_eiref =
1567 (struct btrfs_extent_inline_ref *)(info + 1);
1568 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001569 } else {
1570 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1571 }
1572 *ptr = (unsigned long)*out_eiref;
Liu Bocd857dd2014-06-08 19:04:13 +08001573 if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001574 return -ENOENT;
1575 }
1576
1577 end = (unsigned long)ei + item_size;
Liu Bo6eda71d2014-06-09 10:54:07 +08001578 *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
Jan Schmidta542ad12011-06-13 19:52:59 +02001579 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1580
1581 *ptr += btrfs_extent_inline_ref_size(*out_type);
1582 WARN_ON(*ptr > end);
1583 if (*ptr == end)
1584 return 1; /* last */
1585
1586 return 0;
1587}
1588
1589/*
1590 * reads the tree block backref for an extent. tree level and root are returned
1591 * through out_level and out_root. ptr must point to a 0 value for the first
1592 * call and may be modified (see __get_extent_inline_ref comment).
1593 * returns 0 if data was provided, 1 if there was no more data to provide or
1594 * <0 on error.
1595 */
1596int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001597 struct btrfs_key *key, struct btrfs_extent_item *ei,
1598 u32 item_size, u64 *out_root, u8 *out_level)
Jan Schmidta542ad12011-06-13 19:52:59 +02001599{
1600 int ret;
1601 int type;
Jan Schmidta542ad12011-06-13 19:52:59 +02001602 struct btrfs_extent_inline_ref *eiref;
1603
1604 if (*ptr == (unsigned long)-1)
1605 return 1;
1606
1607 while (1) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001608 ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1609 &eiref, &type);
Jan Schmidta542ad12011-06-13 19:52:59 +02001610 if (ret < 0)
1611 return ret;
1612
1613 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1614 type == BTRFS_SHARED_BLOCK_REF_KEY)
1615 break;
1616
1617 if (ret == 1)
1618 return 1;
1619 }
1620
1621 /* we can treat both ref types equally here */
Jan Schmidta542ad12011-06-13 19:52:59 +02001622 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
Filipe Mananaa1317f42014-12-15 16:04:42 +00001623
1624 if (key->type == BTRFS_EXTENT_ITEM_KEY) {
1625 struct btrfs_tree_block_info *info;
1626
1627 info = (struct btrfs_tree_block_info *)(ei + 1);
1628 *out_level = btrfs_tree_block_level(eb, info);
1629 } else {
1630 ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
1631 *out_level = (u8)key->offset;
1632 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001633
1634 if (ret == 1)
1635 *ptr = (unsigned long)-1;
1636
1637 return 0;
1638}
1639
Jan Schmidt976b1902012-05-17 16:43:03 +02001640static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1641 u64 root, u64 extent_item_objectid,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001642 iterate_extent_inodes_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001643{
Jan Schmidt976b1902012-05-17 16:43:03 +02001644 struct extent_inode_elem *eie;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001645 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001646
Jan Schmidt976b1902012-05-17 16:43:03 +02001647 for (eie = inode_list; eie; eie = eie->next) {
Jan Schmidt4692cf52011-12-02 14:56:41 +01001648 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
Jan Schmidt976b1902012-05-17 16:43:03 +02001649 "root %llu\n", extent_item_objectid,
1650 eie->inum, eie->offset, root);
1651 ret = iterate(eie->inum, eie->offset, root, ctx);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001652 if (ret) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001653 pr_debug("stopping iteration for %llu due to ret=%d\n",
1654 extent_item_objectid, ret);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001655 break;
1656 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001657 }
1658
Jan Schmidta542ad12011-06-13 19:52:59 +02001659 return ret;
1660}
1661
1662/*
1663 * calls iterate() for every inode that references the extent identified by
Jan Schmidt4692cf52011-12-02 14:56:41 +01001664 * the given parameters.
Jan Schmidta542ad12011-06-13 19:52:59 +02001665 * when the iterator function returns a non-zero value, iteration stops.
1666 */
1667int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001668 u64 extent_item_objectid, u64 extent_item_pos,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001669 int search_commit_root,
Jan Schmidta542ad12011-06-13 19:52:59 +02001670 iterate_extent_inodes_t *iterate, void *ctx)
1671{
Jan Schmidta542ad12011-06-13 19:52:59 +02001672 int ret;
Josef Bacikda61d312013-06-12 16:20:08 -04001673 struct btrfs_trans_handle *trans = NULL;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001674 struct ulist *refs = NULL;
1675 struct ulist *roots = NULL;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001676 struct ulist_node *ref_node = NULL;
1677 struct ulist_node *root_node = NULL;
David Sterba3284da72015-02-25 15:47:32 +01001678 struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001679 struct ulist_iterator ref_uiter;
1680 struct ulist_iterator root_uiter;
Jan Schmidta542ad12011-06-13 19:52:59 +02001681
Jan Schmidt4692cf52011-12-02 14:56:41 +01001682 pr_debug("resolving all inodes for extent %llu\n",
1683 extent_item_objectid);
1684
Josef Bacikda61d312013-06-12 16:20:08 -04001685 if (!search_commit_root) {
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001686 trans = btrfs_join_transaction(fs_info->extent_root);
1687 if (IS_ERR(trans))
1688 return PTR_ERR(trans);
Jan Schmidt8445f612012-05-16 18:36:03 +02001689 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Josef Bacik9e351cc2014-03-13 15:42:13 -04001690 } else {
1691 down_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001692 }
Jan Schmidt4692cf52011-12-02 14:56:41 +01001693
1694 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001695 tree_mod_seq_elem.seq, &refs,
Jan Schmidt8445f612012-05-16 18:36:03 +02001696 &extent_item_pos);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001697 if (ret)
1698 goto out;
1699
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001700 ULIST_ITER_INIT(&ref_uiter);
1701 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
Josef Bacik9e351cc2014-03-13 15:42:13 -04001702 ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
1703 tree_mod_seq_elem.seq, &roots);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001704 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001705 break;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001706 ULIST_ITER_INIT(&root_uiter);
1707 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001708 pr_debug("root %llu references leaf %llu, data list "
Alexander Block34d73f52012-07-28 16:18:58 +02001709 "%#llx\n", root_node->val, ref_node->val,
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001710 ref_node->aux);
Jan Schmidt995e01b2012-08-13 02:52:38 -06001711 ret = iterate_leaf_refs((struct extent_inode_elem *)
1712 (uintptr_t)ref_node->aux,
1713 root_node->val,
1714 extent_item_objectid,
1715 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001716 }
Jan Schmidt976b1902012-05-17 16:43:03 +02001717 ulist_free(roots);
Jan Schmidta542ad12011-06-13 19:52:59 +02001718 }
1719
Jan Schmidt976b1902012-05-17 16:43:03 +02001720 free_leaf_list(refs);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001721out:
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001722 if (!search_commit_root) {
Jan Schmidt8445f612012-05-16 18:36:03 +02001723 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001724 btrfs_end_transaction(trans, fs_info->extent_root);
Josef Bacik9e351cc2014-03-13 15:42:13 -04001725 } else {
1726 up_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001727 }
1728
Jan Schmidta542ad12011-06-13 19:52:59 +02001729 return ret;
1730}
1731
1732int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1733 struct btrfs_path *path,
1734 iterate_extent_inodes_t *iterate, void *ctx)
1735{
1736 int ret;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001737 u64 extent_item_pos;
Liu Bo69917e42012-09-07 20:01:28 -06001738 u64 flags = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001739 struct btrfs_key found_key;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001740 int search_commit_root = path->search_commit_root;
Jan Schmidta542ad12011-06-13 19:52:59 +02001741
Liu Bo69917e42012-09-07 20:01:28 -06001742 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001743 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001744 if (ret < 0)
1745 return ret;
Liu Bo69917e42012-09-07 20:01:28 -06001746 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
Stefan Behrens3627bf42012-08-01 04:28:01 -06001747 return -EINVAL;
Jan Schmidta542ad12011-06-13 19:52:59 +02001748
Jan Schmidt4692cf52011-12-02 14:56:41 +01001749 extent_item_pos = logical - found_key.objectid;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001750 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1751 extent_item_pos, search_commit_root,
1752 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001753
1754 return ret;
1755}
1756
Mark Fashehd24bec32012-08-08 11:33:54 -07001757typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1758 struct extent_buffer *eb, void *ctx);
1759
1760static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1761 struct btrfs_path *path,
1762 iterate_irefs_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001763{
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001764 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001765 int slot;
1766 u32 cur;
1767 u32 len;
1768 u32 name_len;
1769 u64 parent = 0;
1770 int found = 0;
1771 struct extent_buffer *eb;
1772 struct btrfs_item *item;
1773 struct btrfs_inode_ref *iref;
1774 struct btrfs_key found_key;
1775
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001776 while (!ret) {
David Sterbac234a242015-01-02 19:03:17 +01001777 ret = btrfs_find_item(fs_root, path, inum,
1778 parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
1779 &found_key);
1780
Jan Schmidta542ad12011-06-13 19:52:59 +02001781 if (ret < 0)
1782 break;
1783 if (ret) {
1784 ret = found ? 0 : -ENOENT;
1785 break;
1786 }
1787 ++found;
1788
1789 parent = found_key.offset;
1790 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00001791 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1792 if (!eb) {
1793 ret = -ENOMEM;
1794 break;
1795 }
1796 extent_buffer_get(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02001797 btrfs_tree_read_lock(eb);
1798 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidta542ad12011-06-13 19:52:59 +02001799 btrfs_release_path(path);
1800
Ross Kirkdd3cc162013-09-16 15:58:09 +01001801 item = btrfs_item_nr(slot);
Jan Schmidta542ad12011-06-13 19:52:59 +02001802 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1803
1804 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1805 name_len = btrfs_inode_ref_name_len(eb, iref);
1806 /* path must be released before calling iterate()! */
Jan Schmidt4692cf52011-12-02 14:56:41 +01001807 pr_debug("following ref at offset %u for inode %llu in "
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001808 "tree %llu\n", cur, found_key.objectid,
1809 fs_root->objectid);
Mark Fashehd24bec32012-08-08 11:33:54 -07001810 ret = iterate(parent, name_len,
1811 (unsigned long)(iref + 1), eb, ctx);
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001812 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001813 break;
Jan Schmidta542ad12011-06-13 19:52:59 +02001814 len = sizeof(*iref) + name_len;
1815 iref = (struct btrfs_inode_ref *)((char *)iref + len);
1816 }
Jan Schmidtb916a592012-04-13 12:28:08 +02001817 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001818 free_extent_buffer(eb);
1819 }
1820
1821 btrfs_release_path(path);
1822
1823 return ret;
1824}
1825
Mark Fashehd24bec32012-08-08 11:33:54 -07001826static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1827 struct btrfs_path *path,
1828 iterate_irefs_t *iterate, void *ctx)
1829{
1830 int ret;
1831 int slot;
1832 u64 offset = 0;
1833 u64 parent;
1834 int found = 0;
1835 struct extent_buffer *eb;
1836 struct btrfs_inode_extref *extref;
Mark Fashehd24bec32012-08-08 11:33:54 -07001837 u32 item_size;
1838 u32 cur_offset;
1839 unsigned long ptr;
1840
1841 while (1) {
1842 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1843 &offset);
1844 if (ret < 0)
1845 break;
1846 if (ret) {
1847 ret = found ? 0 : -ENOENT;
1848 break;
1849 }
1850 ++found;
1851
1852 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00001853 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1854 if (!eb) {
1855 ret = -ENOMEM;
1856 break;
1857 }
1858 extent_buffer_get(eb);
Mark Fashehd24bec32012-08-08 11:33:54 -07001859
1860 btrfs_tree_read_lock(eb);
1861 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1862 btrfs_release_path(path);
1863
Chris Mason2849a852015-10-13 14:06:48 -04001864 item_size = btrfs_item_size_nr(eb, slot);
1865 ptr = btrfs_item_ptr_offset(eb, slot);
Mark Fashehd24bec32012-08-08 11:33:54 -07001866 cur_offset = 0;
1867
1868 while (cur_offset < item_size) {
1869 u32 name_len;
1870
1871 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1872 parent = btrfs_inode_extref_parent(eb, extref);
1873 name_len = btrfs_inode_extref_name_len(eb, extref);
1874 ret = iterate(parent, name_len,
1875 (unsigned long)&extref->name, eb, ctx);
1876 if (ret)
1877 break;
1878
Chris Mason2849a852015-10-13 14:06:48 -04001879 cur_offset += btrfs_inode_extref_name_len(eb, extref);
Mark Fashehd24bec32012-08-08 11:33:54 -07001880 cur_offset += sizeof(*extref);
1881 }
1882 btrfs_tree_read_unlock_blocking(eb);
1883 free_extent_buffer(eb);
1884
1885 offset++;
1886 }
1887
1888 btrfs_release_path(path);
1889
1890 return ret;
1891}
1892
1893static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1894 struct btrfs_path *path, iterate_irefs_t *iterate,
1895 void *ctx)
1896{
1897 int ret;
1898 int found_refs = 0;
1899
1900 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1901 if (!ret)
1902 ++found_refs;
1903 else if (ret != -ENOENT)
1904 return ret;
1905
1906 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1907 if (ret == -ENOENT && found_refs)
1908 return 0;
1909
1910 return ret;
1911}
1912
Jan Schmidta542ad12011-06-13 19:52:59 +02001913/*
1914 * returns 0 if the path could be dumped (probably truncated)
1915 * returns <0 in case of an error
1916 */
Mark Fashehd24bec32012-08-08 11:33:54 -07001917static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1918 struct extent_buffer *eb, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001919{
1920 struct inode_fs_paths *ipath = ctx;
1921 char *fspath;
1922 char *fspath_min;
1923 int i = ipath->fspath->elem_cnt;
1924 const int s_ptr = sizeof(char *);
1925 u32 bytes_left;
1926
1927 bytes_left = ipath->fspath->bytes_left > s_ptr ?
1928 ipath->fspath->bytes_left - s_ptr : 0;
1929
Chris Mason740c3d22011-11-02 15:48:34 -04001930 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
Jan Schmidt96b5bd72012-10-15 08:30:45 +00001931 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1932 name_off, eb, inum, fspath_min, bytes_left);
Jan Schmidta542ad12011-06-13 19:52:59 +02001933 if (IS_ERR(fspath))
1934 return PTR_ERR(fspath);
1935
1936 if (fspath > fspath_min) {
Jeff Mahoney745c4d82011-11-20 07:31:57 -05001937 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
Jan Schmidta542ad12011-06-13 19:52:59 +02001938 ++ipath->fspath->elem_cnt;
1939 ipath->fspath->bytes_left = fspath - fspath_min;
1940 } else {
1941 ++ipath->fspath->elem_missed;
1942 ipath->fspath->bytes_missing += fspath_min - fspath;
1943 ipath->fspath->bytes_left = 0;
1944 }
1945
1946 return 0;
1947}
1948
1949/*
1950 * this dumps all file system paths to the inode into the ipath struct, provided
1951 * is has been created large enough. each path is zero-terminated and accessed
Chris Mason740c3d22011-11-02 15:48:34 -04001952 * from ipath->fspath->val[i].
Jan Schmidta542ad12011-06-13 19:52:59 +02001953 * when it returns, there are ipath->fspath->elem_cnt number of paths available
Chris Mason740c3d22011-11-02 15:48:34 -04001954 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
Jan Schmidta542ad12011-06-13 19:52:59 +02001955 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1956 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1957 * have been needed to return all paths.
1958 */
1959int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1960{
1961 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
Mark Fashehd24bec32012-08-08 11:33:54 -07001962 inode_to_path, ipath);
Jan Schmidta542ad12011-06-13 19:52:59 +02001963}
1964
Jan Schmidta542ad12011-06-13 19:52:59 +02001965struct btrfs_data_container *init_data_container(u32 total_bytes)
1966{
1967 struct btrfs_data_container *data;
1968 size_t alloc_bytes;
1969
1970 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
Liu Bo425d17a2012-09-07 20:01:30 -06001971 data = vmalloc(alloc_bytes);
Jan Schmidta542ad12011-06-13 19:52:59 +02001972 if (!data)
1973 return ERR_PTR(-ENOMEM);
1974
1975 if (total_bytes >= sizeof(*data)) {
1976 data->bytes_left = total_bytes - sizeof(*data);
1977 data->bytes_missing = 0;
1978 } else {
1979 data->bytes_missing = sizeof(*data) - total_bytes;
1980 data->bytes_left = 0;
1981 }
1982
1983 data->elem_cnt = 0;
1984 data->elem_missed = 0;
1985
1986 return data;
1987}
1988
1989/*
1990 * allocates space to return multiple file system paths for an inode.
1991 * total_bytes to allocate are passed, note that space usable for actual path
1992 * information will be total_bytes - sizeof(struct inode_fs_paths).
1993 * the returned pointer must be freed with free_ipath() in the end.
1994 */
1995struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1996 struct btrfs_path *path)
1997{
1998 struct inode_fs_paths *ifp;
1999 struct btrfs_data_container *fspath;
2000
2001 fspath = init_data_container(total_bytes);
2002 if (IS_ERR(fspath))
2003 return (void *)fspath;
2004
2005 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
2006 if (!ifp) {
2007 kfree(fspath);
2008 return ERR_PTR(-ENOMEM);
2009 }
2010
2011 ifp->btrfs_path = path;
2012 ifp->fspath = fspath;
2013 ifp->fs_root = fs_root;
2014
2015 return ifp;
2016}
2017
2018void free_ipath(struct inode_fs_paths *ipath)
2019{
Jesper Juhl4735fb22012-04-12 22:47:52 +02002020 if (!ipath)
2021 return;
Liu Bo425d17a2012-09-07 20:01:30 -06002022 vfree(ipath->fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02002023 kfree(ipath);
2024}