blob: 85dc7ab8f89e15718614045e63f06ceb5819ecbc [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>
Lu Fengqiafce7722016-06-13 09:36:46 +080020#include <linux/rbtree.h>
Jan Schmidta542ad12011-06-13 19:52:59 +020021#include "ctree.h"
22#include "disk-io.h"
23#include "backref.h"
Jan Schmidt8da6d582011-11-23 18:55:04 +010024#include "ulist.h"
25#include "transaction.h"
26#include "delayed-ref.h"
Jan Schmidtb916a592012-04-13 12:28:08 +020027#include "locking.h"
Jan Schmidta542ad12011-06-13 19:52:59 +020028
Josef Bacikdc046b12014-09-10 16:20:45 -040029/* Just an arbitrary number so we can be sure this happened */
30#define BACKREF_FOUND_SHARED 6
31
Jan Schmidt976b1902012-05-17 16:43:03 +020032struct extent_inode_elem {
33 u64 inum;
34 u64 offset;
35 struct extent_inode_elem *next;
36};
37
Lu Fengqiafce7722016-06-13 09:36:46 +080038/*
39 * ref_root is used as the root of the ref tree that hold a collection
40 * of unique references.
41 */
42struct ref_root {
43 struct rb_root rb_root;
44
45 /*
46 * The unique_refs represents the number of ref_nodes with a positive
47 * count stored in the tree. Even if a ref_node (the count is greater
48 * than one) is added, the unique_refs will only increase by one.
49 */
50 unsigned int unique_refs;
51};
52
53/* ref_node is used to store a unique reference to the ref tree. */
54struct ref_node {
55 struct rb_node rb_node;
56
57 /* For NORMAL_REF, otherwise all these fields should be set to 0 */
58 u64 root_id;
59 u64 object_id;
60 u64 offset;
61
62 /* For SHARED_REF, otherwise parent field should be set to 0 */
63 u64 parent;
64
65 /* Ref to the ref_mod of btrfs_delayed_ref_node */
66 int ref_mod;
67};
68
69/* Dynamically allocate and initialize a ref_root */
70static struct ref_root *ref_root_alloc(void)
71{
72 struct ref_root *ref_tree;
73
74 ref_tree = kmalloc(sizeof(*ref_tree), GFP_NOFS);
75 if (!ref_tree)
76 return NULL;
77
78 ref_tree->rb_root = RB_ROOT;
79 ref_tree->unique_refs = 0;
80
81 return ref_tree;
82}
83
84/* Free all nodes in the ref tree, and reinit ref_root */
85static void ref_root_fini(struct ref_root *ref_tree)
86{
87 struct ref_node *node;
88 struct rb_node *next;
89
90 while ((next = rb_first(&ref_tree->rb_root)) != NULL) {
91 node = rb_entry(next, struct ref_node, rb_node);
92 rb_erase(next, &ref_tree->rb_root);
93 kfree(node);
94 }
95
96 ref_tree->rb_root = RB_ROOT;
97 ref_tree->unique_refs = 0;
98}
99
100static void ref_root_free(struct ref_root *ref_tree)
101{
102 if (!ref_tree)
103 return;
104
105 ref_root_fini(ref_tree);
106 kfree(ref_tree);
107}
108
109/*
110 * Compare ref_node with (root_id, object_id, offset, parent)
111 *
112 * The function compares two ref_node a and b. It returns an integer less
113 * than, equal to, or greater than zero , respectively, to be less than, to
114 * equal, or be greater than b.
115 */
116static int ref_node_cmp(struct ref_node *a, struct ref_node *b)
117{
118 if (a->root_id < b->root_id)
119 return -1;
120 else if (a->root_id > b->root_id)
121 return 1;
122
123 if (a->object_id < b->object_id)
124 return -1;
125 else if (a->object_id > b->object_id)
126 return 1;
127
128 if (a->offset < b->offset)
129 return -1;
130 else if (a->offset > b->offset)
131 return 1;
132
133 if (a->parent < b->parent)
134 return -1;
135 else if (a->parent > b->parent)
136 return 1;
137
138 return 0;
139}
140
141/*
142 * Search ref_node with (root_id, object_id, offset, parent) in the tree
143 *
144 * if found, the pointer of the ref_node will be returned;
145 * if not found, NULL will be returned and pos will point to the rb_node for
146 * insert, pos_parent will point to pos'parent for insert;
147*/
148static struct ref_node *__ref_tree_search(struct ref_root *ref_tree,
149 struct rb_node ***pos,
150 struct rb_node **pos_parent,
151 u64 root_id, u64 object_id,
152 u64 offset, u64 parent)
153{
154 struct ref_node *cur = NULL;
155 struct ref_node entry;
156 int ret;
157
158 entry.root_id = root_id;
159 entry.object_id = object_id;
160 entry.offset = offset;
161 entry.parent = parent;
162
163 *pos = &ref_tree->rb_root.rb_node;
164
165 while (**pos) {
166 *pos_parent = **pos;
167 cur = rb_entry(*pos_parent, struct ref_node, rb_node);
168
169 ret = ref_node_cmp(cur, &entry);
170 if (ret > 0)
171 *pos = &(**pos)->rb_left;
172 else if (ret < 0)
173 *pos = &(**pos)->rb_right;
174 else
175 return cur;
176 }
177
178 return NULL;
179}
180
181/*
182 * Insert a ref_node to the ref tree
183 * @pos used for specifiy the position to insert
184 * @pos_parent for specifiy pos's parent
185 *
186 * success, return 0;
187 * ref_node already exists, return -EEXIST;
188*/
189static int ref_tree_insert(struct ref_root *ref_tree, struct rb_node **pos,
190 struct rb_node *pos_parent, struct ref_node *ins)
191{
192 struct rb_node **p = NULL;
193 struct rb_node *parent = NULL;
194 struct ref_node *cur = NULL;
195
196 if (!pos) {
197 cur = __ref_tree_search(ref_tree, &p, &parent, ins->root_id,
198 ins->object_id, ins->offset,
199 ins->parent);
200 if (cur)
201 return -EEXIST;
202 } else {
203 p = pos;
204 parent = pos_parent;
205 }
206
207 rb_link_node(&ins->rb_node, parent, p);
208 rb_insert_color(&ins->rb_node, &ref_tree->rb_root);
209
210 return 0;
211}
212
213/* Erase and free ref_node, caller should update ref_root->unique_refs */
214static void ref_tree_remove(struct ref_root *ref_tree, struct ref_node *node)
215{
216 rb_erase(&node->rb_node, &ref_tree->rb_root);
217 kfree(node);
218}
219
220/*
221 * Update ref_root->unique_refs
222 *
223 * Call __ref_tree_search
224 * 1. if ref_node doesn't exist, ref_tree_insert this node, and update
225 * ref_root->unique_refs:
226 * if ref_node->ref_mod > 0, ref_root->unique_refs++;
227 * if ref_node->ref_mod < 0, do noting;
228 *
229 * 2. if ref_node is found, then get origin ref_node->ref_mod, and update
230 * ref_node->ref_mod.
231 * if ref_node->ref_mod is equal to 0,then call ref_tree_remove
232 *
233 * according to origin_mod and new_mod, update ref_root->items
234 * +----------------+--------------+-------------+
235 * | |new_count <= 0|new_count > 0|
236 * +----------------+--------------+-------------+
237 * |origin_count < 0| 0 | 1 |
238 * +----------------+--------------+-------------+
239 * |origin_count > 0| -1 | 0 |
240 * +----------------+--------------+-------------+
241 *
242 * In case of allocation failure, -ENOMEM is returned and the ref_tree stays
243 * unaltered.
244 * Success, return 0
245 */
246static int ref_tree_add(struct ref_root *ref_tree, u64 root_id, u64 object_id,
247 u64 offset, u64 parent, int count)
248{
249 struct ref_node *node = NULL;
250 struct rb_node **pos = NULL;
251 struct rb_node *pos_parent = NULL;
252 int origin_count;
253 int ret;
254
255 if (!count)
256 return 0;
257
258 node = __ref_tree_search(ref_tree, &pos, &pos_parent, root_id,
259 object_id, offset, parent);
260 if (node == NULL) {
261 node = kmalloc(sizeof(*node), GFP_NOFS);
262 if (!node)
263 return -ENOMEM;
264
265 node->root_id = root_id;
266 node->object_id = object_id;
267 node->offset = offset;
268 node->parent = parent;
269 node->ref_mod = count;
270
271 ret = ref_tree_insert(ref_tree, pos, pos_parent, node);
272 ASSERT(!ret);
273 if (ret) {
274 kfree(node);
275 return ret;
276 }
277
278 ref_tree->unique_refs += node->ref_mod > 0 ? 1 : 0;
279
280 return 0;
281 }
282
283 origin_count = node->ref_mod;
284 node->ref_mod += count;
285
286 if (node->ref_mod > 0)
287 ref_tree->unique_refs += origin_count > 0 ? 0 : 1;
288 else if (node->ref_mod <= 0)
289 ref_tree->unique_refs += origin_count > 0 ? -1 : 0;
290
291 if (!node->ref_mod)
292 ref_tree_remove(ref_tree, node);
293
294 return 0;
295}
296
Jan Schmidt976b1902012-05-17 16:43:03 +0200297static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
298 struct btrfs_file_extent_item *fi,
299 u64 extent_item_pos,
300 struct extent_inode_elem **eie)
301{
Josef Bacik8ca15e02013-07-05 13:58:19 -0400302 u64 offset = 0;
Jan Schmidt976b1902012-05-17 16:43:03 +0200303 struct extent_inode_elem *e;
304
Josef Bacik8ca15e02013-07-05 13:58:19 -0400305 if (!btrfs_file_extent_compression(eb, fi) &&
306 !btrfs_file_extent_encryption(eb, fi) &&
307 !btrfs_file_extent_other_encoding(eb, fi)) {
308 u64 data_offset;
309 u64 data_len;
Jan Schmidt976b1902012-05-17 16:43:03 +0200310
Josef Bacik8ca15e02013-07-05 13:58:19 -0400311 data_offset = btrfs_file_extent_offset(eb, fi);
312 data_len = btrfs_file_extent_num_bytes(eb, fi);
313
314 if (extent_item_pos < data_offset ||
315 extent_item_pos >= data_offset + data_len)
316 return 1;
317 offset = extent_item_pos - data_offset;
318 }
Jan Schmidt976b1902012-05-17 16:43:03 +0200319
320 e = kmalloc(sizeof(*e), GFP_NOFS);
321 if (!e)
322 return -ENOMEM;
323
324 e->next = *eie;
325 e->inum = key->objectid;
Josef Bacik8ca15e02013-07-05 13:58:19 -0400326 e->offset = key->offset + offset;
Jan Schmidt976b1902012-05-17 16:43:03 +0200327 *eie = e;
328
329 return 0;
330}
331
Wang Shilongf05c4742014-01-28 19:13:38 +0800332static void free_inode_elem_list(struct extent_inode_elem *eie)
333{
334 struct extent_inode_elem *eie_next;
335
336 for (; eie; eie = eie_next) {
337 eie_next = eie->next;
338 kfree(eie);
339 }
340}
341
Jan Schmidt976b1902012-05-17 16:43:03 +0200342static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
343 u64 extent_item_pos,
344 struct extent_inode_elem **eie)
345{
346 u64 disk_byte;
347 struct btrfs_key key;
348 struct btrfs_file_extent_item *fi;
349 int slot;
350 int nritems;
351 int extent_type;
352 int ret;
353
354 /*
355 * from the shared data ref, we only have the leaf but we need
356 * the key. thus, we must look into all items and see that we
357 * find one (some) with a reference to our extent item.
358 */
359 nritems = btrfs_header_nritems(eb);
360 for (slot = 0; slot < nritems; ++slot) {
361 btrfs_item_key_to_cpu(eb, &key, slot);
362 if (key.type != BTRFS_EXTENT_DATA_KEY)
363 continue;
364 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
365 extent_type = btrfs_file_extent_type(eb, fi);
366 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
367 continue;
368 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
369 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
370 if (disk_byte != wanted_disk_byte)
371 continue;
372
373 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
374 if (ret < 0)
375 return ret;
376 }
377
378 return 0;
379}
380
Jan Schmidt8da6d582011-11-23 18:55:04 +0100381/*
382 * this structure records all encountered refs on the way up to the root
383 */
384struct __prelim_ref {
385 struct list_head list;
386 u64 root_id;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200387 struct btrfs_key key_for_search;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100388 int level;
389 int count;
Jan Schmidt33019582012-05-30 18:05:21 +0200390 struct extent_inode_elem *inode_list;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100391 u64 parent;
392 u64 wanted_disk_byte;
393};
394
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800395static struct kmem_cache *btrfs_prelim_ref_cache;
396
397int __init btrfs_prelim_ref_init(void)
398{
399 btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
400 sizeof(struct __prelim_ref),
401 0,
Nikolay Borisovfba4b692016-06-23 21:17:08 +0300402 SLAB_MEM_SPREAD,
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800403 NULL);
404 if (!btrfs_prelim_ref_cache)
405 return -ENOMEM;
406 return 0;
407}
408
409void btrfs_prelim_ref_exit(void)
410{
Kinglong Mee5598e902016-01-29 21:36:35 +0800411 kmem_cache_destroy(btrfs_prelim_ref_cache);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800412}
413
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200414/*
415 * the rules for all callers of this function are:
416 * - obtaining the parent is the goal
417 * - if you add a key, you must know that it is a correct key
418 * - if you cannot add the parent or a correct key, then we will look into the
419 * block later to set a correct key
420 *
421 * delayed refs
422 * ============
423 * backref type | shared | indirect | shared | indirect
424 * information | tree | tree | data | data
425 * --------------------+--------+----------+--------+----------
426 * parent logical | y | - | - | -
427 * key to resolve | - | y | y | y
428 * tree block logical | - | - | - | -
429 * root for resolving | y | y | y | y
430 *
431 * - column 1: we've the parent -> done
432 * - column 2, 3, 4: we use the key to find the parent
433 *
434 * on disk refs (inline or keyed)
435 * ==============================
436 * backref type | shared | indirect | shared | indirect
437 * information | tree | tree | data | data
438 * --------------------+--------+----------+--------+----------
439 * parent logical | y | - | y | -
440 * key to resolve | - | - | - | y
441 * tree block logical | y | y | y | y
442 * root for resolving | - | y | y | y
443 *
444 * - column 1, 3: we've the parent -> done
445 * - column 2: we take the first key from the block to find the parent
446 * (see __add_missing_keys)
447 * - column 4: we use the key to find the parent
448 *
449 * additional information that's available but not required to find the parent
450 * block might help in merging entries to gain some speed.
451 */
452
Jan Schmidt8da6d582011-11-23 18:55:04 +0100453static int __add_prelim_ref(struct list_head *head, u64 root_id,
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200454 struct btrfs_key *key, int level,
Wang Shilong742916b2013-08-06 10:29:54 +0800455 u64 parent, u64 wanted_disk_byte, int count,
456 gfp_t gfp_mask)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100457{
458 struct __prelim_ref *ref;
459
Liu Bo48ec4732013-10-30 13:25:24 +0800460 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
461 return 0;
462
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800463 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100464 if (!ref)
465 return -ENOMEM;
466
467 ref->root_id = root_id;
Filipe Mananad6589102015-07-29 17:21:17 +0100468 if (key) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200469 ref->key_for_search = *key;
Filipe Mananad6589102015-07-29 17:21:17 +0100470 /*
471 * We can often find data backrefs with an offset that is too
472 * large (>= LLONG_MAX, maximum allowed file offset) due to
473 * underflows when subtracting a file's offset with the data
474 * offset of its corresponding extent data item. This can
475 * happen for example in the clone ioctl.
476 * So if we detect such case we set the search key's offset to
477 * zero to make sure we will find the matching file extent item
478 * at add_all_parents(), otherwise we will miss it because the
479 * offset taken form the backref is much larger then the offset
480 * of the file extent item. This can make us scan a very large
481 * number of file extent items, but at least it will not make
482 * us miss any.
483 * This is an ugly workaround for a behaviour that should have
484 * never existed, but it does and a fix for the clone ioctl
485 * would touch a lot of places, cause backwards incompatibility
486 * and would not fix the problem for extents cloned with older
487 * kernels.
488 */
489 if (ref->key_for_search.type == BTRFS_EXTENT_DATA_KEY &&
490 ref->key_for_search.offset >= LLONG_MAX)
491 ref->key_for_search.offset = 0;
492 } else {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200493 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
Filipe Mananad6589102015-07-29 17:21:17 +0100494 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100495
Jan Schmidt33019582012-05-30 18:05:21 +0200496 ref->inode_list = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100497 ref->level = level;
498 ref->count = count;
499 ref->parent = parent;
500 ref->wanted_disk_byte = wanted_disk_byte;
501 list_add_tail(&ref->list, head);
502
503 return 0;
504}
505
506static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500507 struct ulist *parents, struct __prelim_ref *ref,
Josef Bacik44853862014-03-19 13:35:14 -0400508 int level, u64 time_seq, const u64 *extent_item_pos,
509 u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100510{
Alexander Block69bca402012-06-19 07:42:26 -0600511 int ret = 0;
512 int slot;
513 struct extent_buffer *eb;
514 struct btrfs_key key;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500515 struct btrfs_key *key_for_search = &ref->key_for_search;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100516 struct btrfs_file_extent_item *fi;
Josef Baciked8c4912013-07-05 14:03:47 -0400517 struct extent_inode_elem *eie = NULL, *old = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100518 u64 disk_byte;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500519 u64 wanted_disk_byte = ref->wanted_disk_byte;
520 u64 count = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100521
Alexander Block69bca402012-06-19 07:42:26 -0600522 if (level != 0) {
523 eb = path->nodes[level];
524 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
Jan Schmidt33019582012-05-30 18:05:21 +0200525 if (ret < 0)
526 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100527 return 0;
Alexander Block69bca402012-06-19 07:42:26 -0600528 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100529
530 /*
Alexander Block69bca402012-06-19 07:42:26 -0600531 * We normally enter this function with the path already pointing to
532 * the first item to check. But sometimes, we may enter it with
533 * slot==nritems. In that case, go to the next leaf before we continue.
Jan Schmidt8da6d582011-11-23 18:55:04 +0100534 */
Qu Wenruo21633fc2015-04-16 14:54:50 +0800535 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
536 if (time_seq == (u64)-1)
537 ret = btrfs_next_leaf(root, path);
538 else
539 ret = btrfs_next_old_leaf(root, path, time_seq);
540 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100541
Josef Bacik44853862014-03-19 13:35:14 -0400542 while (!ret && count < total_refs) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100543 eb = path->nodes[0];
Alexander Block69bca402012-06-19 07:42:26 -0600544 slot = path->slots[0];
545
546 btrfs_item_key_to_cpu(eb, &key, slot);
547
548 if (key.objectid != key_for_search->objectid ||
549 key.type != BTRFS_EXTENT_DATA_KEY)
550 break;
551
552 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
553 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
554
555 if (disk_byte == wanted_disk_byte) {
556 eie = NULL;
Josef Baciked8c4912013-07-05 14:03:47 -0400557 old = NULL;
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500558 count++;
Alexander Block69bca402012-06-19 07:42:26 -0600559 if (extent_item_pos) {
560 ret = check_extent_in_eb(&key, eb, fi,
561 *extent_item_pos,
562 &eie);
563 if (ret < 0)
564 break;
565 }
Josef Baciked8c4912013-07-05 14:03:47 -0400566 if (ret > 0)
567 goto next;
Takashi Iwai4eb1f662014-07-28 10:57:04 +0200568 ret = ulist_add_merge_ptr(parents, eb->start,
569 eie, (void **)&old, GFP_NOFS);
Josef Baciked8c4912013-07-05 14:03:47 -0400570 if (ret < 0)
571 break;
572 if (!ret && extent_item_pos) {
573 while (old->next)
574 old = old->next;
575 old->next = eie;
Alexander Block69bca402012-06-19 07:42:26 -0600576 }
Wang Shilongf05c4742014-01-28 19:13:38 +0800577 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100578 }
Josef Baciked8c4912013-07-05 14:03:47 -0400579next:
Qu Wenruo21633fc2015-04-16 14:54:50 +0800580 if (time_seq == (u64)-1)
581 ret = btrfs_next_item(root, path);
582 else
583 ret = btrfs_next_old_item(root, path, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100584 }
585
Alexander Block69bca402012-06-19 07:42:26 -0600586 if (ret > 0)
587 ret = 0;
Wang Shilongf05c4742014-01-28 19:13:38 +0800588 else if (ret < 0)
589 free_inode_elem_list(eie);
Alexander Block69bca402012-06-19 07:42:26 -0600590 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100591}
592
593/*
594 * resolve an indirect backref in the form (root_id, key, level)
595 * to a logical address
596 */
597static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400598 struct btrfs_path *path, u64 time_seq,
599 struct __prelim_ref *ref,
600 struct ulist *parents,
Josef Bacik44853862014-03-19 13:35:14 -0400601 const u64 *extent_item_pos, u64 total_refs)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100602{
Jan Schmidt8da6d582011-11-23 18:55:04 +0100603 struct btrfs_root *root;
604 struct btrfs_key root_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100605 struct extent_buffer *eb;
606 int ret = 0;
607 int root_level;
608 int level = ref->level;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800609 int index;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100610
Jan Schmidt8da6d582011-11-23 18:55:04 +0100611 root_key.objectid = ref->root_id;
612 root_key.type = BTRFS_ROOT_ITEM_KEY;
613 root_key.offset = (u64)-1;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800614
615 index = srcu_read_lock(&fs_info->subvol_srcu);
616
Josef Bacik2d9e9772015-11-05 14:37:58 -0800617 root = btrfs_get_fs_root(fs_info, &root_key, false);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100618 if (IS_ERR(root)) {
Wang Shilong538f72cd2014-01-23 13:47:48 +0800619 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100620 ret = PTR_ERR(root);
621 goto out;
622 }
623
Jeff Mahoneyf5ee5c92016-06-21 09:52:41 -0400624 if (btrfs_is_testing(fs_info)) {
Josef Bacikd9ee5222015-10-05 10:35:29 -0400625 srcu_read_unlock(&fs_info->subvol_srcu, index);
626 ret = -ENOENT;
627 goto out;
628 }
629
Josef Bacik9e351cc2014-03-13 15:42:13 -0400630 if (path->search_commit_root)
631 root_level = btrfs_header_level(root->commit_root);
Qu Wenruo21633fc2015-04-16 14:54:50 +0800632 else if (time_seq == (u64)-1)
633 root_level = btrfs_header_level(root->node);
Josef Bacik9e351cc2014-03-13 15:42:13 -0400634 else
635 root_level = btrfs_old_root_level(root, time_seq);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100636
Wang Shilong538f72cd2014-01-23 13:47:48 +0800637 if (root_level + 1 == level) {
638 srcu_read_unlock(&fs_info->subvol_srcu, index);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100639 goto out;
Wang Shilong538f72cd2014-01-23 13:47:48 +0800640 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100641
642 path->lowest_level = level;
Qu Wenruo21633fc2015-04-16 14:54:50 +0800643 if (time_seq == (u64)-1)
644 ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
645 0, 0);
646 else
647 ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
648 time_seq);
Wang Shilong538f72cd2014-01-23 13:47:48 +0800649
650 /* root node has been locked, we can release @subvol_srcu safely here */
651 srcu_read_unlock(&fs_info->subvol_srcu, index);
652
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -0400653 btrfs_debug(fs_info,
654 "search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +0200655 ref->root_id, level, ref->count, ret,
656 ref->key_for_search.objectid, ref->key_for_search.type,
657 ref->key_for_search.offset);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100658 if (ret < 0)
659 goto out;
660
661 eb = path->nodes[level];
Jan Schmidt93454572012-06-27 15:23:09 +0200662 while (!eb) {
Dulshani Gunawardhanafae7f212013-10-31 10:30:08 +0530663 if (WARN_ON(!level)) {
Jan Schmidt93454572012-06-27 15:23:09 +0200664 ret = 1;
665 goto out;
666 }
667 level--;
668 eb = path->nodes[level];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100669 }
670
Josef Bacik7ef81ac2014-01-24 14:05:42 -0500671 ret = add_all_parents(root, path, parents, ref, level, time_seq,
Josef Bacik44853862014-03-19 13:35:14 -0400672 extent_item_pos, total_refs);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100673out:
Josef Bacikda61d312013-06-12 16:20:08 -0400674 path->lowest_level = 0;
675 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100676 return ret;
677}
678
679/*
680 * resolve all indirect backrefs from the list
681 */
682static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
Josef Bacikda61d312013-06-12 16:20:08 -0400683 struct btrfs_path *path, u64 time_seq,
Jan Schmidt976b1902012-05-17 16:43:03 +0200684 struct list_head *head,
Josef Bacikdc046b12014-09-10 16:20:45 -0400685 const u64 *extent_item_pos, u64 total_refs,
686 u64 root_objectid)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100687{
688 int err;
689 int ret = 0;
690 struct __prelim_ref *ref;
691 struct __prelim_ref *ref_safe;
692 struct __prelim_ref *new_ref;
693 struct ulist *parents;
694 struct ulist_node *node;
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200695 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100696
697 parents = ulist_alloc(GFP_NOFS);
698 if (!parents)
699 return -ENOMEM;
700
701 /*
702 * _safe allows us to insert directly after the current item without
703 * iterating over the newly inserted items.
704 * we're also allowed to re-assign ref during iteration.
705 */
706 list_for_each_entry_safe(ref, ref_safe, head, list) {
707 if (ref->parent) /* already direct */
708 continue;
709 if (ref->count == 0)
710 continue;
Josef Bacikdc046b12014-09-10 16:20:45 -0400711 if (root_objectid && ref->root_id != root_objectid) {
712 ret = BACKREF_FOUND_SHARED;
713 goto out;
714 }
Josef Bacikda61d312013-06-12 16:20:08 -0400715 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
Josef Bacik44853862014-03-19 13:35:14 -0400716 parents, extent_item_pos,
717 total_refs);
Wang Shilong95def2ed2014-01-23 13:47:49 +0800718 /*
719 * we can only tolerate ENOENT,otherwise,we should catch error
720 * and return directly.
721 */
722 if (err == -ENOENT) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100723 continue;
Wang Shilong95def2ed2014-01-23 13:47:49 +0800724 } else if (err) {
725 ret = err;
726 goto out;
727 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100728
729 /* we put the first parent into the ref at hand */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200730 ULIST_ITER_INIT(&uiter);
731 node = ulist_next(parents, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100732 ref->parent = node ? node->val : 0;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600733 ref->inode_list = node ?
Stefan Behrens35a36212013-08-14 18:12:25 +0200734 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100735
736 /* additional parents require new refs being added here */
Jan Schmidtcd1b4132012-05-22 14:56:50 +0200737 while ((node = ulist_next(parents, &uiter))) {
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800738 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
739 GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100740 if (!new_ref) {
741 ret = -ENOMEM;
Wang Shilonge36902d2013-04-15 10:26:38 +0000742 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100743 }
744 memcpy(new_ref, ref, sizeof(*ref));
745 new_ref->parent = node->val;
Jan Schmidt995e01b2012-08-13 02:52:38 -0600746 new_ref->inode_list = (struct extent_inode_elem *)
747 (uintptr_t)node->aux;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100748 list_add(&new_ref->list, &ref->list);
749 }
750 ulist_reinit(parents);
751 }
Wang Shilonge36902d2013-04-15 10:26:38 +0000752out:
Jan Schmidt8da6d582011-11-23 18:55:04 +0100753 ulist_free(parents);
754 return ret;
755}
756
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200757static inline int ref_for_same_block(struct __prelim_ref *ref1,
758 struct __prelim_ref *ref2)
759{
760 if (ref1->level != ref2->level)
761 return 0;
762 if (ref1->root_id != ref2->root_id)
763 return 0;
764 if (ref1->key_for_search.type != ref2->key_for_search.type)
765 return 0;
766 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
767 return 0;
768 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
769 return 0;
770 if (ref1->parent != ref2->parent)
771 return 0;
772
773 return 1;
774}
775
776/*
777 * read tree blocks and add keys where required.
778 */
779static int __add_missing_keys(struct btrfs_fs_info *fs_info,
780 struct list_head *head)
781{
Geliang Tanga7ca4222015-12-21 23:50:23 +0800782 struct __prelim_ref *ref;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200783 struct extent_buffer *eb;
784
Geliang Tanga7ca4222015-12-21 23:50:23 +0800785 list_for_each_entry(ref, head, list) {
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200786 if (ref->parent)
787 continue;
788 if (ref->key_for_search.type)
789 continue;
790 BUG_ON(!ref->wanted_disk_byte);
791 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
David Sterbace86cd52014-06-15 01:07:32 +0200792 0);
Liu Bo64c043d2015-05-25 17:30:15 +0800793 if (IS_ERR(eb)) {
794 return PTR_ERR(eb);
795 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -0400796 free_extent_buffer(eb);
797 return -EIO;
798 }
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200799 btrfs_tree_read_lock(eb);
800 if (btrfs_header_level(eb) == 0)
801 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
802 else
803 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
804 btrfs_tree_read_unlock(eb);
805 free_extent_buffer(eb);
806 }
807 return 0;
808}
809
Jan Schmidt8da6d582011-11-23 18:55:04 +0100810/*
Qu Wenruo00db6462015-04-01 14:39:06 +0800811 * merge backrefs and adjust counts accordingly
Jan Schmidt8da6d582011-11-23 18:55:04 +0100812 *
813 * mode = 1: merge identical keys, if key is set
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200814 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
815 * additionally, we could even add a key range for the blocks we
816 * looked into to merge even more (-> replace unresolved refs by those
817 * having a parent).
Jan Schmidt8da6d582011-11-23 18:55:04 +0100818 * mode = 2: merge identical parents
819 */
Wang Shilong692206b2013-04-11 07:08:55 +0000820static void __merge_refs(struct list_head *head, int mode)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100821{
Geliang Tang8e217852016-01-13 22:08:01 +0800822 struct __prelim_ref *pos1;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100823
Geliang Tang8e217852016-01-13 22:08:01 +0800824 list_for_each_entry(pos1, head, list) {
825 struct __prelim_ref *pos2 = pos1, *tmp;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100826
Geliang Tang8e217852016-01-13 22:08:01 +0800827 list_for_each_entry_safe_continue(pos2, tmp, head, list) {
Dave Jones8f682f62016-01-28 15:28:35 -0500828 struct __prelim_ref *ref1 = pos1, *ref2 = pos2;
Alexander Block3ef59692012-11-08 21:27:24 +0000829 struct extent_inode_elem *eie;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100830
Qu Wenruo00db6462015-04-01 14:39:06 +0800831 if (!ref_for_same_block(ref1, ref2))
832 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100833 if (mode == 1) {
Dave Jones8f682f62016-01-28 15:28:35 -0500834 if (!ref1->parent && ref2->parent)
835 swap(ref1, ref2);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100836 } else {
837 if (ref1->parent != ref2->parent)
838 continue;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100839 }
Alexander Block3ef59692012-11-08 21:27:24 +0000840
841 eie = ref1->inode_list;
842 while (eie && eie->next)
843 eie = eie->next;
844 if (eie)
845 eie->next = ref2->inode_list;
846 else
847 ref1->inode_list = ref2->inode_list;
848 ref1->count += ref2->count;
849
Jan Schmidt8da6d582011-11-23 18:55:04 +0100850 list_del(&ref2->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +0800851 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
Qu Wenruod8422ba32016-07-20 15:04:18 +0800852 cond_resched();
Jan Schmidt8da6d582011-11-23 18:55:04 +0100853 }
854
855 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100856}
857
858/*
859 * add all currently queued delayed refs from this head whose seq nr is
860 * smaller or equal that seq to the list
861 */
862static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
Josef Bacikdc046b12014-09-10 16:20:45 -0400863 struct list_head *prefs, u64 *total_refs,
864 u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100865{
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800866 struct btrfs_delayed_ref_node *node;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100867 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200868 struct btrfs_key key;
869 struct btrfs_key op_key = {0};
Jan Schmidt8da6d582011-11-23 18:55:04 +0100870 int sgn;
Jan Schmidtb1375d62012-01-26 15:01:11 -0500871 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100872
873 if (extent_op && extent_op->update_key)
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200874 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100875
Josef Bacikd7df2c72014-01-23 09:21:38 -0500876 spin_lock(&head->lock);
Qu Wenruoc6fc2452015-03-30 17:03:00 +0800877 list_for_each_entry(node, &head->ref_list, list) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100878 if (node->seq > seq)
879 continue;
880
881 switch (node->action) {
882 case BTRFS_ADD_DELAYED_EXTENT:
883 case BTRFS_UPDATE_DELAYED_HEAD:
884 WARN_ON(1);
885 continue;
886 case BTRFS_ADD_DELAYED_REF:
887 sgn = 1;
888 break;
889 case BTRFS_DROP_DELAYED_REF:
890 sgn = -1;
891 break;
892 default:
893 BUG_ON(1);
894 }
Josef Bacik44853862014-03-19 13:35:14 -0400895 *total_refs += (node->ref_mod * sgn);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100896 switch (node->type) {
897 case BTRFS_TREE_BLOCK_REF_KEY: {
898 struct btrfs_delayed_tree_ref *ref;
899
900 ref = btrfs_delayed_node_to_tree_ref(node);
Jan Schmidtd5c88b72012-05-15 17:55:51 +0200901 ret = __add_prelim_ref(prefs, ref->root, &op_key,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100902 ref->level + 1, 0, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800903 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100904 break;
905 }
906 case BTRFS_SHARED_BLOCK_REF_KEY: {
907 struct btrfs_delayed_tree_ref *ref;
908
909 ref = btrfs_delayed_node_to_tree_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800910 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100911 ref->level + 1, ref->parent,
912 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800913 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100914 break;
915 }
916 case BTRFS_EXTENT_DATA_REF_KEY: {
917 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100918 ref = btrfs_delayed_node_to_data_ref(node);
919
920 key.objectid = ref->objectid;
921 key.type = BTRFS_EXTENT_DATA_KEY;
922 key.offset = ref->offset;
Josef Bacikdc046b12014-09-10 16:20:45 -0400923
924 /*
925 * Found a inum that doesn't match our known inum, we
926 * know it's shared.
927 */
928 if (inum && ref->objectid != inum) {
929 ret = BACKREF_FOUND_SHARED;
930 break;
931 }
932
Jan Schmidt8da6d582011-11-23 18:55:04 +0100933 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
934 node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800935 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100936 break;
937 }
938 case BTRFS_SHARED_DATA_REF_KEY: {
939 struct btrfs_delayed_data_ref *ref;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100940
941 ref = btrfs_delayed_node_to_data_ref(node);
Liu Boacdf8982015-07-28 18:03:30 +0800942 ret = __add_prelim_ref(prefs, 0, NULL, 0,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100943 ref->parent, node->bytenr,
Wang Shilong742916b2013-08-06 10:29:54 +0800944 node->ref_mod * sgn, GFP_ATOMIC);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100945 break;
946 }
947 default:
948 WARN_ON(1);
949 }
Wang Shilong1149ab62013-04-10 11:22:50 +0000950 if (ret)
Josef Bacikd7df2c72014-01-23 09:21:38 -0500951 break;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100952 }
Josef Bacikd7df2c72014-01-23 09:21:38 -0500953 spin_unlock(&head->lock);
954 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100955}
956
957/*
958 * add all inline backrefs for bytenr to the list
959 */
960static int __add_inline_refs(struct btrfs_fs_info *fs_info,
961 struct btrfs_path *path, u64 bytenr,
Josef Bacik44853862014-03-19 13:35:14 -0400962 int *info_level, struct list_head *prefs,
Lu Fengqiafce7722016-06-13 09:36:46 +0800963 struct ref_root *ref_tree,
Josef Bacikdc046b12014-09-10 16:20:45 -0400964 u64 *total_refs, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +0100965{
Jan Schmidtb1375d62012-01-26 15:01:11 -0500966 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100967 int slot;
968 struct extent_buffer *leaf;
969 struct btrfs_key key;
Josef Bacik261c84b2013-06-28 13:11:22 -0400970 struct btrfs_key found_key;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100971 unsigned long ptr;
972 unsigned long end;
973 struct btrfs_extent_item *ei;
974 u64 flags;
975 u64 item_size;
976
977 /*
978 * enumerate all inline refs
979 */
980 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +0200981 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +0100982
983 item_size = btrfs_item_size_nr(leaf, slot);
984 BUG_ON(item_size < sizeof(*ei));
985
986 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
987 flags = btrfs_extent_flags(leaf, ei);
Josef Bacik44853862014-03-19 13:35:14 -0400988 *total_refs += btrfs_extent_refs(leaf, ei);
Josef Bacik261c84b2013-06-28 13:11:22 -0400989 btrfs_item_key_to_cpu(leaf, &found_key, slot);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100990
991 ptr = (unsigned long)(ei + 1);
992 end = (unsigned long)ei + item_size;
993
Josef Bacik261c84b2013-06-28 13:11:22 -0400994 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
995 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Jan Schmidt8da6d582011-11-23 18:55:04 +0100996 struct btrfs_tree_block_info *info;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100997
998 info = (struct btrfs_tree_block_info *)ptr;
999 *info_level = btrfs_tree_block_level(leaf, info);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001000 ptr += sizeof(struct btrfs_tree_block_info);
1001 BUG_ON(ptr > end);
Josef Bacik261c84b2013-06-28 13:11:22 -04001002 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
1003 *info_level = found_key.offset;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001004 } else {
1005 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1006 }
1007
1008 while (ptr < end) {
1009 struct btrfs_extent_inline_ref *iref;
1010 u64 offset;
1011 int type;
1012
1013 iref = (struct btrfs_extent_inline_ref *)ptr;
1014 type = btrfs_extent_inline_ref_type(leaf, iref);
1015 offset = btrfs_extent_inline_ref_offset(leaf, iref);
1016
1017 switch (type) {
1018 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001019 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +01001020 *info_level + 1, offset,
Wang Shilong742916b2013-08-06 10:29:54 +08001021 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001022 break;
1023 case BTRFS_SHARED_DATA_REF_KEY: {
1024 struct btrfs_shared_data_ref *sdref;
1025 int count;
1026
1027 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
1028 count = btrfs_shared_data_ref_count(leaf, sdref);
1029 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
Wang Shilong742916b2013-08-06 10:29:54 +08001030 bytenr, count, GFP_NOFS);
Lu Fengqiafce7722016-06-13 09:36:46 +08001031 if (ref_tree) {
1032 if (!ret)
1033 ret = ref_tree_add(ref_tree, 0, 0, 0,
1034 bytenr, count);
1035 if (!ret && ref_tree->unique_refs > 1)
1036 ret = BACKREF_FOUND_SHARED;
1037 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001038 break;
1039 }
1040 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001041 ret = __add_prelim_ref(prefs, offset, NULL,
1042 *info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +08001043 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001044 break;
1045 case BTRFS_EXTENT_DATA_REF_KEY: {
1046 struct btrfs_extent_data_ref *dref;
1047 int count;
1048 u64 root;
1049
1050 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1051 count = btrfs_extent_data_ref_count(leaf, dref);
1052 key.objectid = btrfs_extent_data_ref_objectid(leaf,
1053 dref);
1054 key.type = BTRFS_EXTENT_DATA_KEY;
1055 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -04001056
1057 if (inum && key.objectid != inum) {
1058 ret = BACKREF_FOUND_SHARED;
1059 break;
1060 }
1061
Jan Schmidt8da6d582011-11-23 18:55:04 +01001062 root = btrfs_extent_data_ref_root(leaf, dref);
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001063 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +08001064 bytenr, count, GFP_NOFS);
Lu Fengqiafce7722016-06-13 09:36:46 +08001065 if (ref_tree) {
1066 if (!ret)
1067 ret = ref_tree_add(ref_tree, root,
1068 key.objectid,
1069 key.offset, 0,
1070 count);
1071 if (!ret && ref_tree->unique_refs > 1)
1072 ret = BACKREF_FOUND_SHARED;
1073 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001074 break;
1075 }
1076 default:
1077 WARN_ON(1);
1078 }
Wang Shilong1149ab62013-04-10 11:22:50 +00001079 if (ret)
1080 return ret;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001081 ptr += btrfs_extent_inline_ref_size(type);
1082 }
1083
1084 return 0;
1085}
1086
1087/*
1088 * add all non-inline backrefs for bytenr to the list
1089 */
1090static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
1091 struct btrfs_path *path, u64 bytenr,
Lu Fengqiafce7722016-06-13 09:36:46 +08001092 int info_level, struct list_head *prefs,
1093 struct ref_root *ref_tree, u64 inum)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001094{
1095 struct btrfs_root *extent_root = fs_info->extent_root;
1096 int ret;
1097 int slot;
1098 struct extent_buffer *leaf;
1099 struct btrfs_key key;
1100
1101 while (1) {
1102 ret = btrfs_next_item(extent_root, path);
1103 if (ret < 0)
1104 break;
1105 if (ret) {
1106 ret = 0;
1107 break;
1108 }
1109
1110 slot = path->slots[0];
1111 leaf = path->nodes[0];
1112 btrfs_item_key_to_cpu(leaf, &key, slot);
1113
1114 if (key.objectid != bytenr)
1115 break;
1116 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
1117 continue;
1118 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
1119 break;
1120
1121 switch (key.type) {
1122 case BTRFS_SHARED_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001123 ret = __add_prelim_ref(prefs, 0, NULL,
Jan Schmidt8da6d582011-11-23 18:55:04 +01001124 info_level + 1, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +08001125 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001126 break;
1127 case BTRFS_SHARED_DATA_REF_KEY: {
1128 struct btrfs_shared_data_ref *sdref;
1129 int count;
1130
1131 sdref = btrfs_item_ptr(leaf, slot,
1132 struct btrfs_shared_data_ref);
1133 count = btrfs_shared_data_ref_count(leaf, sdref);
1134 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
Wang Shilong742916b2013-08-06 10:29:54 +08001135 bytenr, count, GFP_NOFS);
Lu Fengqiafce7722016-06-13 09:36:46 +08001136 if (ref_tree) {
1137 if (!ret)
1138 ret = ref_tree_add(ref_tree, 0, 0, 0,
1139 bytenr, count);
1140 if (!ret && ref_tree->unique_refs > 1)
1141 ret = BACKREF_FOUND_SHARED;
1142 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001143 break;
1144 }
1145 case BTRFS_TREE_BLOCK_REF_KEY:
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001146 ret = __add_prelim_ref(prefs, key.offset, NULL,
1147 info_level + 1, 0,
Wang Shilong742916b2013-08-06 10:29:54 +08001148 bytenr, 1, GFP_NOFS);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001149 break;
1150 case BTRFS_EXTENT_DATA_REF_KEY: {
1151 struct btrfs_extent_data_ref *dref;
1152 int count;
1153 u64 root;
1154
1155 dref = btrfs_item_ptr(leaf, slot,
1156 struct btrfs_extent_data_ref);
1157 count = btrfs_extent_data_ref_count(leaf, dref);
1158 key.objectid = btrfs_extent_data_ref_objectid(leaf,
1159 dref);
1160 key.type = BTRFS_EXTENT_DATA_KEY;
1161 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
Josef Bacikdc046b12014-09-10 16:20:45 -04001162
1163 if (inum && key.objectid != inum) {
1164 ret = BACKREF_FOUND_SHARED;
1165 break;
1166 }
1167
Jan Schmidt8da6d582011-11-23 18:55:04 +01001168 root = btrfs_extent_data_ref_root(leaf, dref);
1169 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
Wang Shilong742916b2013-08-06 10:29:54 +08001170 bytenr, count, GFP_NOFS);
Lu Fengqiafce7722016-06-13 09:36:46 +08001171 if (ref_tree) {
1172 if (!ret)
1173 ret = ref_tree_add(ref_tree, root,
1174 key.objectid,
1175 key.offset, 0,
1176 count);
1177 if (!ret && ref_tree->unique_refs > 1)
1178 ret = BACKREF_FOUND_SHARED;
1179 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001180 break;
1181 }
1182 default:
1183 WARN_ON(1);
1184 }
Wang Shilong1149ab62013-04-10 11:22:50 +00001185 if (ret)
1186 return ret;
1187
Jan Schmidt8da6d582011-11-23 18:55:04 +01001188 }
1189
1190 return ret;
1191}
1192
1193/*
1194 * this adds all existing backrefs (inline backrefs, backrefs and delayed
1195 * refs) for the given bytenr to the refs list, merges duplicates and resolves
1196 * indirect refs to their parent bytenr.
1197 * When roots are found, they're added to the roots list
1198 *
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001199 * NOTE: This can return values > 0
1200 *
Qu Wenruo21633fc2015-04-16 14:54:50 +08001201 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
1202 * much like trans == NULL case, the difference only lies in it will not
1203 * commit root.
1204 * The special case is for qgroup to search roots in commit_transaction().
1205 *
Lu Fengqiafce7722016-06-13 09:36:46 +08001206 * If check_shared is set to 1, any extent has more than one ref item, will
1207 * be returned BACKREF_FOUND_SHARED immediately.
1208 *
Jan Schmidt8da6d582011-11-23 18:55:04 +01001209 * FIXME some caching might speed things up
1210 */
1211static int find_parent_nodes(struct btrfs_trans_handle *trans,
1212 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001213 u64 time_seq, struct ulist *refs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001214 struct ulist *roots, const u64 *extent_item_pos,
Lu Fengqiafce7722016-06-13 09:36:46 +08001215 u64 root_objectid, u64 inum, int check_shared)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001216{
1217 struct btrfs_key key;
1218 struct btrfs_path *path;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001219 struct btrfs_delayed_ref_root *delayed_refs = NULL;
Li Zefand3b01062012-03-03 07:41:15 -05001220 struct btrfs_delayed_ref_head *head;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001221 int info_level = 0;
1222 int ret;
1223 struct list_head prefs_delayed;
1224 struct list_head prefs;
1225 struct __prelim_ref *ref;
Wang Shilongf05c4742014-01-28 19:13:38 +08001226 struct extent_inode_elem *eie = NULL;
Lu Fengqiafce7722016-06-13 09:36:46 +08001227 struct ref_root *ref_tree = NULL;
Josef Bacik44853862014-03-19 13:35:14 -04001228 u64 total_refs = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001229
1230 INIT_LIST_HEAD(&prefs);
1231 INIT_LIST_HEAD(&prefs_delayed);
1232
1233 key.objectid = bytenr;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001234 key.offset = (u64)-1;
Josef Bacik261c84b2013-06-28 13:11:22 -04001235 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1236 key.type = BTRFS_METADATA_ITEM_KEY;
1237 else
1238 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001239
1240 path = btrfs_alloc_path();
1241 if (!path)
1242 return -ENOMEM;
Wang Shilonge84752d2014-02-13 11:19:47 +08001243 if (!trans) {
Josef Bacikda61d312013-06-12 16:20:08 -04001244 path->search_commit_root = 1;
Wang Shilonge84752d2014-02-13 11:19:47 +08001245 path->skip_locking = 1;
1246 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001247
Qu Wenruo21633fc2015-04-16 14:54:50 +08001248 if (time_seq == (u64)-1)
1249 path->skip_locking = 1;
1250
Jan Schmidt8da6d582011-11-23 18:55:04 +01001251 /*
1252 * grab both a lock on the path and a lock on the delayed ref head.
1253 * We need both to get a consistent picture of how the refs look
1254 * at a specified point in time
1255 */
1256again:
Li Zefand3b01062012-03-03 07:41:15 -05001257 head = NULL;
1258
Lu Fengqiafce7722016-06-13 09:36:46 +08001259 if (check_shared) {
1260 if (!ref_tree) {
1261 ref_tree = ref_root_alloc();
1262 if (!ref_tree) {
1263 ret = -ENOMEM;
1264 goto out;
1265 }
1266 } else {
1267 ref_root_fini(ref_tree);
1268 }
1269 }
1270
Jan Schmidt8da6d582011-11-23 18:55:04 +01001271 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
1272 if (ret < 0)
1273 goto out;
1274 BUG_ON(ret == 0);
1275
Josef Bacikfaa2dbf2014-05-07 17:06:09 -04001276#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
Qu Wenruo21633fc2015-04-16 14:54:50 +08001277 if (trans && likely(trans->type != __TRANS_DUMMY) &&
1278 time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -04001279#else
Qu Wenruo21633fc2015-04-16 14:54:50 +08001280 if (trans && time_seq != (u64)-1) {
Josef Bacikfaa2dbf2014-05-07 17:06:09 -04001281#endif
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001282 /*
1283 * look if there are updates for this ref queued and lock the
1284 * head
1285 */
1286 delayed_refs = &trans->transaction->delayed_refs;
1287 spin_lock(&delayed_refs->lock);
1288 head = btrfs_find_delayed_ref_head(trans, bytenr);
1289 if (head) {
1290 if (!mutex_trylock(&head->mutex)) {
1291 atomic_inc(&head->node.refs);
1292 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001293
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001294 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001295
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001296 /*
1297 * Mutex was contended, block until it's
1298 * released and try again
1299 */
1300 mutex_lock(&head->mutex);
1301 mutex_unlock(&head->mutex);
1302 btrfs_put_delayed_ref(&head->node);
1303 goto again;
1304 }
Josef Bacikd7df2c72014-01-23 09:21:38 -05001305 spin_unlock(&delayed_refs->lock);
Jan Schmidt097b8a72012-06-21 11:08:04 +02001306 ret = __add_delayed_refs(head, time_seq,
Josef Bacikdc046b12014-09-10 16:20:45 -04001307 &prefs_delayed, &total_refs,
1308 inum);
Jan Schmidt155725c2012-06-22 14:01:00 +02001309 mutex_unlock(&head->mutex);
Josef Bacikd7df2c72014-01-23 09:21:38 -05001310 if (ret)
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001311 goto out;
Josef Bacikd7df2c72014-01-23 09:21:38 -05001312 } else {
1313 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001314 }
Lu Fengqiafce7722016-06-13 09:36:46 +08001315
1316 if (check_shared && !list_empty(&prefs_delayed)) {
1317 /*
1318 * Add all delay_ref to the ref_tree and check if there
1319 * are multiple ref items added.
1320 */
1321 list_for_each_entry(ref, &prefs_delayed, list) {
1322 if (ref->key_for_search.type) {
1323 ret = ref_tree_add(ref_tree,
1324 ref->root_id,
1325 ref->key_for_search.objectid,
1326 ref->key_for_search.offset,
1327 0, ref->count);
1328 if (ret)
1329 goto out;
1330 } else {
1331 ret = ref_tree_add(ref_tree, 0, 0, 0,
1332 ref->parent, ref->count);
1333 if (ret)
1334 goto out;
1335 }
1336
1337 }
1338
1339 if (ref_tree->unique_refs > 1) {
1340 ret = BACKREF_FOUND_SHARED;
1341 goto out;
1342 }
1343
1344 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001345 }
Jan Schmidt8da6d582011-11-23 18:55:04 +01001346
1347 if (path->slots[0]) {
1348 struct extent_buffer *leaf;
1349 int slot;
1350
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001351 path->slots[0]--;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001352 leaf = path->nodes[0];
Jan Schmidtdadcaf72012-05-22 13:43:25 +02001353 slot = path->slots[0];
Jan Schmidt8da6d582011-11-23 18:55:04 +01001354 btrfs_item_key_to_cpu(leaf, &key, slot);
1355 if (key.objectid == bytenr &&
Josef Bacik261c84b2013-06-28 13:11:22 -04001356 (key.type == BTRFS_EXTENT_ITEM_KEY ||
1357 key.type == BTRFS_METADATA_ITEM_KEY)) {
Jan Schmidt8da6d582011-11-23 18:55:04 +01001358 ret = __add_inline_refs(fs_info, path, bytenr,
Josef Bacik44853862014-03-19 13:35:14 -04001359 &info_level, &prefs,
Lu Fengqiafce7722016-06-13 09:36:46 +08001360 ref_tree, &total_refs,
1361 inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001362 if (ret)
1363 goto out;
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001364 ret = __add_keyed_refs(fs_info, path, bytenr,
Lu Fengqiafce7722016-06-13 09:36:46 +08001365 info_level, &prefs,
1366 ref_tree, inum);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001367 if (ret)
1368 goto out;
1369 }
1370 }
1371 btrfs_release_path(path);
1372
Jan Schmidt8da6d582011-11-23 18:55:04 +01001373 list_splice_init(&prefs_delayed, &prefs);
1374
Jan Schmidtd5c88b72012-05-15 17:55:51 +02001375 ret = __add_missing_keys(fs_info, &prefs);
1376 if (ret)
1377 goto out;
1378
Wang Shilong692206b2013-04-11 07:08:55 +00001379 __merge_refs(&prefs, 1);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001380
Josef Bacikda61d312013-06-12 16:20:08 -04001381 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
Josef Bacikdc046b12014-09-10 16:20:45 -04001382 extent_item_pos, total_refs,
1383 root_objectid);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001384 if (ret)
1385 goto out;
1386
Wang Shilong692206b2013-04-11 07:08:55 +00001387 __merge_refs(&prefs, 2);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001388
1389 while (!list_empty(&prefs)) {
1390 ref = list_first_entry(&prefs, struct __prelim_ref, list);
Julia Lawall6c1500f2012-11-03 20:30:18 +00001391 WARN_ON(ref->count < 0);
Wang Shilong98cfee212014-02-01 00:42:05 +08001392 if (roots && ref->count && ref->root_id && ref->parent == 0) {
Josef Bacikdc046b12014-09-10 16:20:45 -04001393 if (root_objectid && ref->root_id != root_objectid) {
1394 ret = BACKREF_FOUND_SHARED;
1395 goto out;
1396 }
1397
Jan Schmidt8da6d582011-11-23 18:55:04 +01001398 /* no parent == root of tree */
1399 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001400 if (ret < 0)
1401 goto out;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001402 }
1403 if (ref->count && ref->parent) {
Josef Bacik8a564572014-06-05 16:08:45 -04001404 if (extent_item_pos && !ref->inode_list &&
1405 ref->level == 0) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001406 struct extent_buffer *eb;
David Sterba707e8a02014-06-04 19:22:26 +02001407
Jan Schmidt976b1902012-05-17 16:43:03 +02001408 eb = read_tree_block(fs_info->extent_root,
David Sterbace86cd52014-06-15 01:07:32 +02001409 ref->parent, 0);
Liu Bo64c043d2015-05-25 17:30:15 +08001410 if (IS_ERR(eb)) {
1411 ret = PTR_ERR(eb);
1412 goto out;
1413 } else if (!extent_buffer_uptodate(eb)) {
Josef Bacik416bc652013-04-23 14:17:42 -04001414 free_extent_buffer(eb);
Wang Shilongc16c2e22013-05-08 08:10:25 +00001415 ret = -EIO;
1416 goto out;
Josef Bacik416bc652013-04-23 14:17:42 -04001417 }
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001418 btrfs_tree_read_lock(eb);
1419 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidt976b1902012-05-17 16:43:03 +02001420 ret = find_extent_in_eb(eb, bytenr,
1421 *extent_item_pos, &eie);
Filipe Manana6f7ff6d2014-07-02 20:07:54 +01001422 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidt976b1902012-05-17 16:43:03 +02001423 free_extent_buffer(eb);
Filipe David Borba Mananaf5929cd2013-07-31 00:26:35 +01001424 if (ret < 0)
1425 goto out;
1426 ref->inode_list = eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001427 }
Takashi Iwai4eb1f662014-07-28 10:57:04 +02001428 ret = ulist_add_merge_ptr(refs, ref->parent,
1429 ref->inode_list,
1430 (void **)&eie, GFP_NOFS);
Wang Shilongf1723932013-03-29 23:03:21 +00001431 if (ret < 0)
1432 goto out;
Jan Schmidt33019582012-05-30 18:05:21 +02001433 if (!ret && extent_item_pos) {
1434 /*
1435 * we've recorded that parent, so we must extend
1436 * its inode list here
1437 */
1438 BUG_ON(!eie);
1439 while (eie->next)
1440 eie = eie->next;
1441 eie->next = ref->inode_list;
1442 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001443 eie = NULL;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001444 }
Wang Shilonga4fdb612013-08-08 13:04:17 +08001445 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001446 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001447 }
1448
1449out:
Jan Schmidt8da6d582011-11-23 18:55:04 +01001450 btrfs_free_path(path);
Lu Fengqiafce7722016-06-13 09:36:46 +08001451 ref_root_free(ref_tree);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001452 while (!list_empty(&prefs)) {
1453 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1454 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001455 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001456 }
1457 while (!list_empty(&prefs_delayed)) {
1458 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1459 list);
1460 list_del(&ref->list);
Wang Shilongb9e9a6c2013-08-09 13:25:36 +08001461 kmem_cache_free(btrfs_prelim_ref_cache, ref);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001462 }
Wang Shilongf05c4742014-01-28 19:13:38 +08001463 if (ret < 0)
1464 free_inode_elem_list(eie);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001465 return ret;
1466}
1467
Jan Schmidt976b1902012-05-17 16:43:03 +02001468static void free_leaf_list(struct ulist *blocks)
1469{
1470 struct ulist_node *node = NULL;
1471 struct extent_inode_elem *eie;
Jan Schmidt976b1902012-05-17 16:43:03 +02001472 struct ulist_iterator uiter;
1473
1474 ULIST_ITER_INIT(&uiter);
1475 while ((node = ulist_next(blocks, &uiter))) {
1476 if (!node->aux)
1477 continue;
Jan Schmidt995e01b2012-08-13 02:52:38 -06001478 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
Wang Shilongf05c4742014-01-28 19:13:38 +08001479 free_inode_elem_list(eie);
Jan Schmidt976b1902012-05-17 16:43:03 +02001480 node->aux = 0;
1481 }
1482
1483 ulist_free(blocks);
1484}
1485
Jan Schmidt8da6d582011-11-23 18:55:04 +01001486/*
1487 * Finds all leafs with a reference to the specified combination of bytenr and
1488 * offset. key_list_head will point to a list of corresponding keys (caller must
1489 * free each list element). The leafs will be stored in the leafs ulist, which
1490 * must be freed with ulist_free.
1491 *
1492 * returns 0 on success, <0 on error
1493 */
1494static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1495 struct btrfs_fs_info *fs_info, u64 bytenr,
Jan Schmidt097b8a72012-06-21 11:08:04 +02001496 u64 time_seq, struct ulist **leafs,
Jan Schmidt976b1902012-05-17 16:43:03 +02001497 const u64 *extent_item_pos)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001498{
Jan Schmidt8da6d582011-11-23 18:55:04 +01001499 int ret;
1500
Jan Schmidt8da6d582011-11-23 18:55:04 +01001501 *leafs = ulist_alloc(GFP_NOFS);
Wang Shilong98cfee212014-02-01 00:42:05 +08001502 if (!*leafs)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001503 return -ENOMEM;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001504
Lu Fengqiafce7722016-06-13 09:36:46 +08001505 ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
1506 *leafs, NULL, extent_item_pos, 0, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001507 if (ret < 0 && ret != -ENOENT) {
Jan Schmidt976b1902012-05-17 16:43:03 +02001508 free_leaf_list(*leafs);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001509 return ret;
1510 }
1511
1512 return 0;
1513}
1514
1515/*
1516 * walk all backrefs for a given extent to find all roots that reference this
1517 * extent. Walking a backref means finding all extents that reference this
1518 * extent and in turn walk the backrefs of those, too. Naturally this is a
1519 * recursive process, but here it is implemented in an iterative fashion: We
1520 * find all referencing extents for the extent in question and put them on a
1521 * list. In turn, we find all referencing extents for those, further appending
1522 * to the list. The way we iterate the list allows adding more elements after
1523 * the current while iterating. The process stops when we reach the end of the
1524 * list. Found roots are added to the roots list.
1525 *
1526 * returns 0 on success, < 0 on error.
1527 */
Josef Bacik9e351cc2014-03-13 15:42:13 -04001528static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1529 struct btrfs_fs_info *fs_info, u64 bytenr,
1530 u64 time_seq, struct ulist **roots)
Jan Schmidt8da6d582011-11-23 18:55:04 +01001531{
1532 struct ulist *tmp;
1533 struct ulist_node *node = NULL;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001534 struct ulist_iterator uiter;
Jan Schmidt8da6d582011-11-23 18:55:04 +01001535 int ret;
1536
1537 tmp = ulist_alloc(GFP_NOFS);
1538 if (!tmp)
1539 return -ENOMEM;
1540 *roots = ulist_alloc(GFP_NOFS);
1541 if (!*roots) {
1542 ulist_free(tmp);
1543 return -ENOMEM;
1544 }
1545
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001546 ULIST_ITER_INIT(&uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001547 while (1) {
Lu Fengqiafce7722016-06-13 09:36:46 +08001548 ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
1549 tmp, *roots, NULL, 0, 0, 0);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001550 if (ret < 0 && ret != -ENOENT) {
1551 ulist_free(tmp);
1552 ulist_free(*roots);
1553 return ret;
1554 }
Jan Schmidtcd1b4132012-05-22 14:56:50 +02001555 node = ulist_next(tmp, &uiter);
Jan Schmidt8da6d582011-11-23 18:55:04 +01001556 if (!node)
1557 break;
1558 bytenr = node->val;
Wang Shilongbca1a292014-01-26 22:32:18 +08001559 cond_resched();
Jan Schmidt8da6d582011-11-23 18:55:04 +01001560 }
1561
1562 ulist_free(tmp);
1563 return 0;
1564}
1565
Josef Bacik9e351cc2014-03-13 15:42:13 -04001566int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1567 struct btrfs_fs_info *fs_info, u64 bytenr,
1568 u64 time_seq, struct ulist **roots)
1569{
1570 int ret;
1571
1572 if (!trans)
1573 down_read(&fs_info->commit_root_sem);
1574 ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1575 if (!trans)
1576 up_read(&fs_info->commit_root_sem);
1577 return ret;
1578}
1579
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001580/**
1581 * btrfs_check_shared - tell us whether an extent is shared
1582 *
1583 * @trans: optional trans handle
1584 *
1585 * btrfs_check_shared uses the backref walking code but will short
1586 * circuit as soon as it finds a root or inode that doesn't match the
1587 * one passed in. This provides a significant performance benefit for
1588 * callers (such as fiemap) which want to know whether the extent is
1589 * shared but do not need a ref count.
1590 *
1591 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1592 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001593int btrfs_check_shared(struct btrfs_trans_handle *trans,
1594 struct btrfs_fs_info *fs_info, u64 root_objectid,
1595 u64 inum, u64 bytenr)
1596{
1597 struct ulist *tmp = NULL;
1598 struct ulist *roots = NULL;
1599 struct ulist_iterator uiter;
1600 struct ulist_node *node;
David Sterba3284da72015-02-25 15:47:32 +01001601 struct seq_list elem = SEQ_LIST_INIT(elem);
Josef Bacikdc046b12014-09-10 16:20:45 -04001602 int ret = 0;
1603
1604 tmp = ulist_alloc(GFP_NOFS);
1605 roots = ulist_alloc(GFP_NOFS);
1606 if (!tmp || !roots) {
1607 ulist_free(tmp);
1608 ulist_free(roots);
1609 return -ENOMEM;
1610 }
1611
1612 if (trans)
1613 btrfs_get_tree_mod_seq(fs_info, &elem);
1614 else
1615 down_read(&fs_info->commit_root_sem);
1616 ULIST_ITER_INIT(&uiter);
1617 while (1) {
1618 ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
Lu Fengqiafce7722016-06-13 09:36:46 +08001619 roots, NULL, root_objectid, inum, 1);
Josef Bacikdc046b12014-09-10 16:20:45 -04001620 if (ret == BACKREF_FOUND_SHARED) {
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001621 /* this is the only condition under which we return 1 */
Josef Bacikdc046b12014-09-10 16:20:45 -04001622 ret = 1;
1623 break;
1624 }
1625 if (ret < 0 && ret != -ENOENT)
1626 break;
Mark Fasheh2c2ed5a2015-05-19 12:49:50 -07001627 ret = 0;
Josef Bacikdc046b12014-09-10 16:20:45 -04001628 node = ulist_next(tmp, &uiter);
1629 if (!node)
1630 break;
1631 bytenr = node->val;
1632 cond_resched();
1633 }
1634 if (trans)
1635 btrfs_put_tree_mod_seq(fs_info, &elem);
1636 else
1637 up_read(&fs_info->commit_root_sem);
1638 ulist_free(tmp);
1639 ulist_free(roots);
1640 return ret;
1641}
1642
Mark Fashehf1863732012-08-08 11:32:27 -07001643int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1644 u64 start_off, struct btrfs_path *path,
1645 struct btrfs_inode_extref **ret_extref,
1646 u64 *found_off)
1647{
1648 int ret, slot;
1649 struct btrfs_key key;
1650 struct btrfs_key found_key;
1651 struct btrfs_inode_extref *extref;
1652 struct extent_buffer *leaf;
1653 unsigned long ptr;
1654
1655 key.objectid = inode_objectid;
David Sterba962a2982014-06-04 18:41:45 +02001656 key.type = BTRFS_INODE_EXTREF_KEY;
Mark Fashehf1863732012-08-08 11:32:27 -07001657 key.offset = start_off;
1658
1659 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1660 if (ret < 0)
1661 return ret;
1662
1663 while (1) {
1664 leaf = path->nodes[0];
1665 slot = path->slots[0];
1666 if (slot >= btrfs_header_nritems(leaf)) {
1667 /*
1668 * If the item at offset is not found,
1669 * btrfs_search_slot will point us to the slot
1670 * where it should be inserted. In our case
1671 * that will be the slot directly before the
1672 * next INODE_REF_KEY_V2 item. In the case
1673 * that we're pointing to the last slot in a
1674 * leaf, we must move one leaf over.
1675 */
1676 ret = btrfs_next_leaf(root, path);
1677 if (ret) {
1678 if (ret >= 1)
1679 ret = -ENOENT;
1680 break;
1681 }
1682 continue;
1683 }
1684
1685 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1686
1687 /*
1688 * Check that we're still looking at an extended ref key for
1689 * this particular objectid. If we have different
1690 * objectid or type then there are no more to be found
1691 * in the tree and we can exit.
1692 */
1693 ret = -ENOENT;
1694 if (found_key.objectid != inode_objectid)
1695 break;
David Sterba962a2982014-06-04 18:41:45 +02001696 if (found_key.type != BTRFS_INODE_EXTREF_KEY)
Mark Fashehf1863732012-08-08 11:32:27 -07001697 break;
1698
1699 ret = 0;
1700 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1701 extref = (struct btrfs_inode_extref *)ptr;
1702 *ret_extref = extref;
1703 if (found_off)
1704 *found_off = found_key.offset;
1705 break;
1706 }
1707
1708 return ret;
1709}
1710
Eric Sandeen48a3b632013-04-25 20:41:01 +00001711/*
1712 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1713 * Elements of the path are separated by '/' and the path is guaranteed to be
1714 * 0-terminated. the path is only given within the current file system.
1715 * Therefore, it never starts with a '/'. the caller is responsible to provide
1716 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1717 * the start point of the resulting string is returned. this pointer is within
1718 * dest, normally.
1719 * in case the path buffer would overflow, the pointer is decremented further
1720 * as if output was written to the buffer, though no more output is actually
1721 * generated. that way, the caller can determine how much space would be
1722 * required for the path to fit into the buffer. in that case, the returned
1723 * value will be smaller than dest. callers must check this!
1724 */
Jan Schmidt96b5bd72012-10-15 08:30:45 +00001725char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1726 u32 name_len, unsigned long name_off,
1727 struct extent_buffer *eb_in, u64 parent,
1728 char *dest, u32 size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001729{
Jan Schmidta542ad12011-06-13 19:52:59 +02001730 int slot;
1731 u64 next_inum;
1732 int ret;
Gabriel de Perthuis661bec62012-10-10 08:50:47 -06001733 s64 bytes_left = ((s64)size) - 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001734 struct extent_buffer *eb = eb_in;
1735 struct btrfs_key found_key;
Jan Schmidtb916a592012-04-13 12:28:08 +02001736 int leave_spinning = path->leave_spinning;
Mark Fashehd24bec32012-08-08 11:33:54 -07001737 struct btrfs_inode_ref *iref;
Jan Schmidta542ad12011-06-13 19:52:59 +02001738
1739 if (bytes_left >= 0)
1740 dest[bytes_left] = '\0';
1741
Jan Schmidtb916a592012-04-13 12:28:08 +02001742 path->leave_spinning = 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001743 while (1) {
Mark Fashehd24bec32012-08-08 11:33:54 -07001744 bytes_left -= name_len;
Jan Schmidta542ad12011-06-13 19:52:59 +02001745 if (bytes_left >= 0)
1746 read_extent_buffer(eb, dest + bytes_left,
Mark Fashehd24bec32012-08-08 11:33:54 -07001747 name_off, name_len);
Jan Schmidtb916a592012-04-13 12:28:08 +02001748 if (eb != eb_in) {
Filipe Manana0c0fe3b2016-02-03 19:17:27 +00001749 if (!path->skip_locking)
1750 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001751 free_extent_buffer(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02001752 }
David Sterbac234a242015-01-02 19:03:17 +01001753 ret = btrfs_find_item(fs_root, path, parent, 0,
1754 BTRFS_INODE_REF_KEY, &found_key);
Jan Schmidt8f24b492012-02-08 16:01:01 +01001755 if (ret > 0)
1756 ret = -ENOENT;
Jan Schmidta542ad12011-06-13 19:52:59 +02001757 if (ret)
1758 break;
Mark Fashehd24bec32012-08-08 11:33:54 -07001759
Jan Schmidta542ad12011-06-13 19:52:59 +02001760 next_inum = found_key.offset;
1761
1762 /* regular exit ahead */
1763 if (parent == next_inum)
1764 break;
1765
1766 slot = path->slots[0];
1767 eb = path->nodes[0];
1768 /* make sure we can use eb after releasing the path */
Jan Schmidtb916a592012-04-13 12:28:08 +02001769 if (eb != eb_in) {
Filipe Manana0c0fe3b2016-02-03 19:17:27 +00001770 if (!path->skip_locking)
1771 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1772 path->nodes[0] = NULL;
1773 path->locks[0] = 0;
Jan Schmidtb916a592012-04-13 12:28:08 +02001774 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001775 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001776 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
Mark Fashehd24bec32012-08-08 11:33:54 -07001777
1778 name_len = btrfs_inode_ref_name_len(eb, iref);
1779 name_off = (unsigned long)(iref + 1);
1780
Jan Schmidta542ad12011-06-13 19:52:59 +02001781 parent = next_inum;
1782 --bytes_left;
1783 if (bytes_left >= 0)
1784 dest[bytes_left] = '/';
1785 }
1786
1787 btrfs_release_path(path);
Jan Schmidtb916a592012-04-13 12:28:08 +02001788 path->leave_spinning = leave_spinning;
Jan Schmidta542ad12011-06-13 19:52:59 +02001789
1790 if (ret)
1791 return ERR_PTR(ret);
1792
1793 return dest + bytes_left;
1794}
1795
1796/*
1797 * this makes the path point to (logical EXTENT_ITEM *)
1798 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1799 * tree blocks and <0 on error.
1800 */
1801int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
Liu Bo69917e42012-09-07 20:01:28 -06001802 struct btrfs_path *path, struct btrfs_key *found_key,
1803 u64 *flags_ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001804{
1805 int ret;
1806 u64 flags;
Josef Bacik261c84b2013-06-28 13:11:22 -04001807 u64 size = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001808 u32 item_size;
1809 struct extent_buffer *eb;
1810 struct btrfs_extent_item *ei;
1811 struct btrfs_key key;
1812
Josef Bacik261c84b2013-06-28 13:11:22 -04001813 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1814 key.type = BTRFS_METADATA_ITEM_KEY;
1815 else
1816 key.type = BTRFS_EXTENT_ITEM_KEY;
Jan Schmidta542ad12011-06-13 19:52:59 +02001817 key.objectid = logical;
1818 key.offset = (u64)-1;
1819
1820 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1821 if (ret < 0)
1822 return ret;
Jan Schmidta542ad12011-06-13 19:52:59 +02001823
Wang Shilong850a8cd2014-02-06 20:02:29 +08001824 ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1825 if (ret) {
1826 if (ret > 0)
1827 ret = -ENOENT;
1828 return ret;
Josef Bacik580f0a62014-01-23 16:03:45 -05001829 }
Wang Shilong850a8cd2014-02-06 20:02:29 +08001830 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
Josef Bacik261c84b2013-06-28 13:11:22 -04001831 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
David Sterba707e8a02014-06-04 19:22:26 +02001832 size = fs_info->extent_root->nodesize;
Josef Bacik261c84b2013-06-28 13:11:22 -04001833 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1834 size = found_key->offset;
1835
Josef Bacik580f0a62014-01-23 16:03:45 -05001836 if (found_key->objectid > logical ||
Josef Bacik261c84b2013-06-28 13:11:22 -04001837 found_key->objectid + size <= logical) {
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04001838 btrfs_debug(fs_info,
1839 "logical %llu is not within any extent", logical);
Jan Schmidta542ad12011-06-13 19:52:59 +02001840 return -ENOENT;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001841 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001842
1843 eb = path->nodes[0];
1844 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1845 BUG_ON(item_size < sizeof(*ei));
1846
1847 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1848 flags = btrfs_extent_flags(eb, ei);
1849
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04001850 btrfs_debug(fs_info,
1851 "logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u",
Geert Uytterhoevenc1c9ff72013-08-20 13:20:07 +02001852 logical, logical - found_key->objectid, found_key->objectid,
1853 found_key->offset, flags, item_size);
Liu Bo69917e42012-09-07 20:01:28 -06001854
1855 WARN_ON(!flags_ret);
1856 if (flags_ret) {
1857 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1858 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1859 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1860 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1861 else
1862 BUG_ON(1);
1863 return 0;
1864 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001865
1866 return -EIO;
1867}
1868
1869/*
1870 * helper function to iterate extent inline refs. ptr must point to a 0 value
1871 * for the first call and may be modified. it is used to track state.
1872 * if more refs exist, 0 is returned and the next call to
1873 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1874 * next ref. after the last ref was processed, 1 is returned.
1875 * returns <0 on error
1876 */
1877static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001878 struct btrfs_key *key,
1879 struct btrfs_extent_item *ei, u32 item_size,
1880 struct btrfs_extent_inline_ref **out_eiref,
1881 int *out_type)
Jan Schmidta542ad12011-06-13 19:52:59 +02001882{
1883 unsigned long end;
1884 u64 flags;
1885 struct btrfs_tree_block_info *info;
1886
1887 if (!*ptr) {
1888 /* first call */
1889 flags = btrfs_extent_flags(eb, ei);
1890 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001891 if (key->type == BTRFS_METADATA_ITEM_KEY) {
1892 /* a skinny metadata extent */
1893 *out_eiref =
1894 (struct btrfs_extent_inline_ref *)(ei + 1);
1895 } else {
1896 WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1897 info = (struct btrfs_tree_block_info *)(ei + 1);
1898 *out_eiref =
1899 (struct btrfs_extent_inline_ref *)(info + 1);
1900 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001901 } else {
1902 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1903 }
1904 *ptr = (unsigned long)*out_eiref;
Liu Bocd857dd2014-06-08 19:04:13 +08001905 if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
Jan Schmidta542ad12011-06-13 19:52:59 +02001906 return -ENOENT;
1907 }
1908
1909 end = (unsigned long)ei + item_size;
Liu Bo6eda71d2014-06-09 10:54:07 +08001910 *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
Jan Schmidta542ad12011-06-13 19:52:59 +02001911 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1912
1913 *ptr += btrfs_extent_inline_ref_size(*out_type);
1914 WARN_ON(*ptr > end);
1915 if (*ptr == end)
1916 return 1; /* last */
1917
1918 return 0;
1919}
1920
1921/*
1922 * reads the tree block backref for an extent. tree level and root are returned
1923 * through out_level and out_root. ptr must point to a 0 value for the first
1924 * call and may be modified (see __get_extent_inline_ref comment).
1925 * returns 0 if data was provided, 1 if there was no more data to provide or
1926 * <0 on error.
1927 */
1928int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
Liu Bo6eda71d2014-06-09 10:54:07 +08001929 struct btrfs_key *key, struct btrfs_extent_item *ei,
1930 u32 item_size, u64 *out_root, u8 *out_level)
Jan Schmidta542ad12011-06-13 19:52:59 +02001931{
1932 int ret;
1933 int type;
Jan Schmidta542ad12011-06-13 19:52:59 +02001934 struct btrfs_extent_inline_ref *eiref;
1935
1936 if (*ptr == (unsigned long)-1)
1937 return 1;
1938
1939 while (1) {
Liu Bo6eda71d2014-06-09 10:54:07 +08001940 ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1941 &eiref, &type);
Jan Schmidta542ad12011-06-13 19:52:59 +02001942 if (ret < 0)
1943 return ret;
1944
1945 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1946 type == BTRFS_SHARED_BLOCK_REF_KEY)
1947 break;
1948
1949 if (ret == 1)
1950 return 1;
1951 }
1952
1953 /* we can treat both ref types equally here */
Jan Schmidta542ad12011-06-13 19:52:59 +02001954 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
Filipe Mananaa1317f42014-12-15 16:04:42 +00001955
1956 if (key->type == BTRFS_EXTENT_ITEM_KEY) {
1957 struct btrfs_tree_block_info *info;
1958
1959 info = (struct btrfs_tree_block_info *)(ei + 1);
1960 *out_level = btrfs_tree_block_level(eb, info);
1961 } else {
1962 ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
1963 *out_level = (u8)key->offset;
1964 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001965
1966 if (ret == 1)
1967 *ptr = (unsigned long)-1;
1968
1969 return 0;
1970}
1971
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04001972static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
1973 struct extent_inode_elem *inode_list,
1974 u64 root, u64 extent_item_objectid,
1975 iterate_extent_inodes_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001976{
Jan Schmidt976b1902012-05-17 16:43:03 +02001977 struct extent_inode_elem *eie;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001978 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001979
Jan Schmidt976b1902012-05-17 16:43:03 +02001980 for (eie = inode_list; eie; eie = eie->next) {
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04001981 btrfs_debug(fs_info,
1982 "ref for %llu resolved, key (%llu EXTEND_DATA %llu), root %llu",
1983 extent_item_objectid, eie->inum,
1984 eie->offset, root);
Jan Schmidt976b1902012-05-17 16:43:03 +02001985 ret = iterate(eie->inum, eie->offset, root, ctx);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001986 if (ret) {
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04001987 btrfs_debug(fs_info,
1988 "stopping iteration for %llu due to ret=%d",
1989 extent_item_objectid, ret);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001990 break;
1991 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001992 }
1993
Jan Schmidta542ad12011-06-13 19:52:59 +02001994 return ret;
1995}
1996
1997/*
1998 * calls iterate() for every inode that references the extent identified by
Jan Schmidt4692cf52011-12-02 14:56:41 +01001999 * the given parameters.
Jan Schmidta542ad12011-06-13 19:52:59 +02002000 * when the iterator function returns a non-zero value, iteration stops.
2001 */
2002int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
Jan Schmidt4692cf52011-12-02 14:56:41 +01002003 u64 extent_item_objectid, u64 extent_item_pos,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002004 int search_commit_root,
Jan Schmidta542ad12011-06-13 19:52:59 +02002005 iterate_extent_inodes_t *iterate, void *ctx)
2006{
Jan Schmidta542ad12011-06-13 19:52:59 +02002007 int ret;
Josef Bacikda61d312013-06-12 16:20:08 -04002008 struct btrfs_trans_handle *trans = NULL;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002009 struct ulist *refs = NULL;
2010 struct ulist *roots = NULL;
Jan Schmidt4692cf52011-12-02 14:56:41 +01002011 struct ulist_node *ref_node = NULL;
2012 struct ulist_node *root_node = NULL;
David Sterba3284da72015-02-25 15:47:32 +01002013 struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
Jan Schmidtcd1b4132012-05-22 14:56:50 +02002014 struct ulist_iterator ref_uiter;
2015 struct ulist_iterator root_uiter;
Jan Schmidta542ad12011-06-13 19:52:59 +02002016
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04002017 btrfs_debug(fs_info, "resolving all inodes for extent %llu",
Jan Schmidt4692cf52011-12-02 14:56:41 +01002018 extent_item_objectid);
2019
Josef Bacikda61d312013-06-12 16:20:08 -04002020 if (!search_commit_root) {
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002021 trans = btrfs_join_transaction(fs_info->extent_root);
2022 if (IS_ERR(trans))
2023 return PTR_ERR(trans);
Jan Schmidt8445f612012-05-16 18:36:03 +02002024 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Josef Bacik9e351cc2014-03-13 15:42:13 -04002025 } else {
2026 down_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002027 }
Jan Schmidt4692cf52011-12-02 14:56:41 +01002028
2029 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
Jan Schmidt097b8a72012-06-21 11:08:04 +02002030 tree_mod_seq_elem.seq, &refs,
Jan Schmidt8445f612012-05-16 18:36:03 +02002031 &extent_item_pos);
Jan Schmidt4692cf52011-12-02 14:56:41 +01002032 if (ret)
2033 goto out;
2034
Jan Schmidtcd1b4132012-05-22 14:56:50 +02002035 ULIST_ITER_INIT(&ref_uiter);
2036 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
Josef Bacik9e351cc2014-03-13 15:42:13 -04002037 ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
2038 tree_mod_seq_elem.seq, &roots);
Jan Schmidt4692cf52011-12-02 14:56:41 +01002039 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02002040 break;
Jan Schmidtcd1b4132012-05-22 14:56:50 +02002041 ULIST_ITER_INIT(&root_uiter);
2042 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04002043 btrfs_debug(fs_info,
2044 "root %llu references leaf %llu, data list %#llx",
2045 root_node->val, ref_node->val,
2046 ref_node->aux);
2047 ret = iterate_leaf_refs(fs_info,
2048 (struct extent_inode_elem *)
Jan Schmidt995e01b2012-08-13 02:52:38 -06002049 (uintptr_t)ref_node->aux,
2050 root_node->val,
2051 extent_item_objectid,
2052 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02002053 }
Jan Schmidt976b1902012-05-17 16:43:03 +02002054 ulist_free(roots);
Jan Schmidta542ad12011-06-13 19:52:59 +02002055 }
2056
Jan Schmidt976b1902012-05-17 16:43:03 +02002057 free_leaf_list(refs);
Jan Schmidt4692cf52011-12-02 14:56:41 +01002058out:
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002059 if (!search_commit_root) {
Jan Schmidt8445f612012-05-16 18:36:03 +02002060 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002061 btrfs_end_transaction(trans, fs_info->extent_root);
Josef Bacik9e351cc2014-03-13 15:42:13 -04002062 } else {
2063 up_read(&fs_info->commit_root_sem);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002064 }
2065
Jan Schmidta542ad12011-06-13 19:52:59 +02002066 return ret;
2067}
2068
2069int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
2070 struct btrfs_path *path,
2071 iterate_extent_inodes_t *iterate, void *ctx)
2072{
2073 int ret;
Jan Schmidt4692cf52011-12-02 14:56:41 +01002074 u64 extent_item_pos;
Liu Bo69917e42012-09-07 20:01:28 -06002075 u64 flags = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02002076 struct btrfs_key found_key;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002077 int search_commit_root = path->search_commit_root;
Jan Schmidta542ad12011-06-13 19:52:59 +02002078
Liu Bo69917e42012-09-07 20:01:28 -06002079 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
Jan Schmidt4692cf52011-12-02 14:56:41 +01002080 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02002081 if (ret < 0)
2082 return ret;
Liu Bo69917e42012-09-07 20:01:28 -06002083 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
Stefan Behrens3627bf42012-08-01 04:28:01 -06002084 return -EINVAL;
Jan Schmidta542ad12011-06-13 19:52:59 +02002085
Jan Schmidt4692cf52011-12-02 14:56:41 +01002086 extent_item_pos = logical - found_key.objectid;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01002087 ret = iterate_extent_inodes(fs_info, found_key.objectid,
2088 extent_item_pos, search_commit_root,
2089 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02002090
2091 return ret;
2092}
2093
Mark Fashehd24bec32012-08-08 11:33:54 -07002094typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
2095 struct extent_buffer *eb, void *ctx);
2096
2097static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
2098 struct btrfs_path *path,
2099 iterate_irefs_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02002100{
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02002101 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02002102 int slot;
2103 u32 cur;
2104 u32 len;
2105 u32 name_len;
2106 u64 parent = 0;
2107 int found = 0;
2108 struct extent_buffer *eb;
2109 struct btrfs_item *item;
2110 struct btrfs_inode_ref *iref;
2111 struct btrfs_key found_key;
2112
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02002113 while (!ret) {
David Sterbac234a242015-01-02 19:03:17 +01002114 ret = btrfs_find_item(fs_root, path, inum,
2115 parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
2116 &found_key);
2117
Jan Schmidta542ad12011-06-13 19:52:59 +02002118 if (ret < 0)
2119 break;
2120 if (ret) {
2121 ret = found ? 0 : -ENOENT;
2122 break;
2123 }
2124 ++found;
2125
2126 parent = found_key.offset;
2127 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00002128 eb = btrfs_clone_extent_buffer(path->nodes[0]);
2129 if (!eb) {
2130 ret = -ENOMEM;
2131 break;
2132 }
2133 extent_buffer_get(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +02002134 btrfs_tree_read_lock(eb);
2135 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidta542ad12011-06-13 19:52:59 +02002136 btrfs_release_path(path);
2137
Ross Kirkdd3cc162013-09-16 15:58:09 +01002138 item = btrfs_item_nr(slot);
Jan Schmidta542ad12011-06-13 19:52:59 +02002139 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
2140
2141 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
2142 name_len = btrfs_inode_ref_name_len(eb, iref);
2143 /* path must be released before calling iterate()! */
Jeff Mahoneyab8d0fc2016-09-20 10:05:02 -04002144 btrfs_debug(fs_root->fs_info,
2145 "following ref at offset %u for inode %llu in tree %llu",
2146 cur, found_key.objectid, fs_root->objectid);
Mark Fashehd24bec32012-08-08 11:33:54 -07002147 ret = iterate(parent, name_len,
2148 (unsigned long)(iref + 1), eb, ctx);
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02002149 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02002150 break;
Jan Schmidta542ad12011-06-13 19:52:59 +02002151 len = sizeof(*iref) + name_len;
2152 iref = (struct btrfs_inode_ref *)((char *)iref + len);
2153 }
Jan Schmidtb916a592012-04-13 12:28:08 +02002154 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02002155 free_extent_buffer(eb);
2156 }
2157
2158 btrfs_release_path(path);
2159
2160 return ret;
2161}
2162
Mark Fashehd24bec32012-08-08 11:33:54 -07002163static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
2164 struct btrfs_path *path,
2165 iterate_irefs_t *iterate, void *ctx)
2166{
2167 int ret;
2168 int slot;
2169 u64 offset = 0;
2170 u64 parent;
2171 int found = 0;
2172 struct extent_buffer *eb;
2173 struct btrfs_inode_extref *extref;
Mark Fashehd24bec32012-08-08 11:33:54 -07002174 u32 item_size;
2175 u32 cur_offset;
2176 unsigned long ptr;
2177
2178 while (1) {
2179 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
2180 &offset);
2181 if (ret < 0)
2182 break;
2183 if (ret) {
2184 ret = found ? 0 : -ENOENT;
2185 break;
2186 }
2187 ++found;
2188
2189 slot = path->slots[0];
Filipe David Borba Manana3fe81ce2013-12-15 12:43:58 +00002190 eb = btrfs_clone_extent_buffer(path->nodes[0]);
2191 if (!eb) {
2192 ret = -ENOMEM;
2193 break;
2194 }
2195 extent_buffer_get(eb);
Mark Fashehd24bec32012-08-08 11:33:54 -07002196
2197 btrfs_tree_read_lock(eb);
2198 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
2199 btrfs_release_path(path);
2200
Chris Mason2849a852015-10-13 14:06:48 -04002201 item_size = btrfs_item_size_nr(eb, slot);
2202 ptr = btrfs_item_ptr_offset(eb, slot);
Mark Fashehd24bec32012-08-08 11:33:54 -07002203 cur_offset = 0;
2204
2205 while (cur_offset < item_size) {
2206 u32 name_len;
2207
2208 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
2209 parent = btrfs_inode_extref_parent(eb, extref);
2210 name_len = btrfs_inode_extref_name_len(eb, extref);
2211 ret = iterate(parent, name_len,
2212 (unsigned long)&extref->name, eb, ctx);
2213 if (ret)
2214 break;
2215
Chris Mason2849a852015-10-13 14:06:48 -04002216 cur_offset += btrfs_inode_extref_name_len(eb, extref);
Mark Fashehd24bec32012-08-08 11:33:54 -07002217 cur_offset += sizeof(*extref);
2218 }
2219 btrfs_tree_read_unlock_blocking(eb);
2220 free_extent_buffer(eb);
2221
2222 offset++;
2223 }
2224
2225 btrfs_release_path(path);
2226
2227 return ret;
2228}
2229
2230static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
2231 struct btrfs_path *path, iterate_irefs_t *iterate,
2232 void *ctx)
2233{
2234 int ret;
2235 int found_refs = 0;
2236
2237 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
2238 if (!ret)
2239 ++found_refs;
2240 else if (ret != -ENOENT)
2241 return ret;
2242
2243 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
2244 if (ret == -ENOENT && found_refs)
2245 return 0;
2246
2247 return ret;
2248}
2249
Jan Schmidta542ad12011-06-13 19:52:59 +02002250/*
2251 * returns 0 if the path could be dumped (probably truncated)
2252 * returns <0 in case of an error
2253 */
Mark Fashehd24bec32012-08-08 11:33:54 -07002254static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
2255 struct extent_buffer *eb, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02002256{
2257 struct inode_fs_paths *ipath = ctx;
2258 char *fspath;
2259 char *fspath_min;
2260 int i = ipath->fspath->elem_cnt;
2261 const int s_ptr = sizeof(char *);
2262 u32 bytes_left;
2263
2264 bytes_left = ipath->fspath->bytes_left > s_ptr ?
2265 ipath->fspath->bytes_left - s_ptr : 0;
2266
Chris Mason740c3d22011-11-02 15:48:34 -04002267 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
Jan Schmidt96b5bd72012-10-15 08:30:45 +00002268 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
2269 name_off, eb, inum, fspath_min, bytes_left);
Jan Schmidta542ad12011-06-13 19:52:59 +02002270 if (IS_ERR(fspath))
2271 return PTR_ERR(fspath);
2272
2273 if (fspath > fspath_min) {
Jeff Mahoney745c4d82011-11-20 07:31:57 -05002274 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
Jan Schmidta542ad12011-06-13 19:52:59 +02002275 ++ipath->fspath->elem_cnt;
2276 ipath->fspath->bytes_left = fspath - fspath_min;
2277 } else {
2278 ++ipath->fspath->elem_missed;
2279 ipath->fspath->bytes_missing += fspath_min - fspath;
2280 ipath->fspath->bytes_left = 0;
2281 }
2282
2283 return 0;
2284}
2285
2286/*
2287 * this dumps all file system paths to the inode into the ipath struct, provided
2288 * is has been created large enough. each path is zero-terminated and accessed
Chris Mason740c3d22011-11-02 15:48:34 -04002289 * from ipath->fspath->val[i].
Jan Schmidta542ad12011-06-13 19:52:59 +02002290 * when it returns, there are ipath->fspath->elem_cnt number of paths available
Chris Mason740c3d22011-11-02 15:48:34 -04002291 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
Nicholas D Steeves01327612016-05-19 21:18:45 -04002292 * number of missed paths is recorded in ipath->fspath->elem_missed, otherwise,
Jan Schmidta542ad12011-06-13 19:52:59 +02002293 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
2294 * have been needed to return all paths.
2295 */
2296int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
2297{
2298 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
Mark Fashehd24bec32012-08-08 11:33:54 -07002299 inode_to_path, ipath);
Jan Schmidta542ad12011-06-13 19:52:59 +02002300}
2301
Jan Schmidta542ad12011-06-13 19:52:59 +02002302struct btrfs_data_container *init_data_container(u32 total_bytes)
2303{
2304 struct btrfs_data_container *data;
2305 size_t alloc_bytes;
2306
2307 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
Liu Bo425d17a2012-09-07 20:01:30 -06002308 data = vmalloc(alloc_bytes);
Jan Schmidta542ad12011-06-13 19:52:59 +02002309 if (!data)
2310 return ERR_PTR(-ENOMEM);
2311
2312 if (total_bytes >= sizeof(*data)) {
2313 data->bytes_left = total_bytes - sizeof(*data);
2314 data->bytes_missing = 0;
2315 } else {
2316 data->bytes_missing = sizeof(*data) - total_bytes;
2317 data->bytes_left = 0;
2318 }
2319
2320 data->elem_cnt = 0;
2321 data->elem_missed = 0;
2322
2323 return data;
2324}
2325
2326/*
2327 * allocates space to return multiple file system paths for an inode.
2328 * total_bytes to allocate are passed, note that space usable for actual path
2329 * information will be total_bytes - sizeof(struct inode_fs_paths).
2330 * the returned pointer must be freed with free_ipath() in the end.
2331 */
2332struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
2333 struct btrfs_path *path)
2334{
2335 struct inode_fs_paths *ifp;
2336 struct btrfs_data_container *fspath;
2337
2338 fspath = init_data_container(total_bytes);
2339 if (IS_ERR(fspath))
2340 return (void *)fspath;
2341
2342 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
2343 if (!ifp) {
Vincent Stehlé72928f22016-05-10 14:56:20 +02002344 vfree(fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02002345 return ERR_PTR(-ENOMEM);
2346 }
2347
2348 ifp->btrfs_path = path;
2349 ifp->fspath = fspath;
2350 ifp->fs_root = fs_root;
2351
2352 return ifp;
2353}
2354
2355void free_ipath(struct inode_fs_paths *ipath)
2356{
Jesper Juhl4735fb22012-04-12 22:47:52 +02002357 if (!ipath)
2358 return;
Liu Bo425d17a2012-09-07 20:01:30 -06002359 vfree(ipath->fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02002360 kfree(ipath);
2361}