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- Committer: Package Import Robot
- Author(s): Dimitri John Ledkov
- Date: 2014-10-23 22:04:07 UTC
- mfrom: (1.2.15) (6.1.40 sid)
- Revision ID: package-import@ubuntu.com-20141023220407-skt9hy0ft4oim95o
Tags: 3.17-1
New upstream release.
- files added:
- backref.c
- files modified:
- .pc/0001-Fixing-unaligned-memory-accesses.patch/ctree.h
added
removed
backref.c
1
/*
2
* Copyright (C) 2011 STRATO. All rights reserved.
3
*
4
* This program is free software; you can redistribute it and/or
5
* modify it under the terms of the GNU General Public
6
* License v2 as published by the Free Software Foundation.
7
*
8
* This program is distributed in the hope that it will be useful,
9
* but WITHOUT ANY WARRANTY; without even the implied warranty of
10
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11
* General Public License for more details.
12
*
13
* You should have received a copy of the GNU General Public
14
* License along with this program; if not, write to the
15
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16
* Boston, MA 021110-1307, USA.
17
*/
18
19
#include "kerncompat.h"
20
#include "ctree.h"
21
#include "disk-io.h"
22
#include "backref.h"
23
#include "ulist.h"
24
#include "transaction.h"
25
26
#define pr_debug(...) do { } while (0)
27
28
struct extent_inode_elem {
29
u64 inum;
30
u64 offset;
31
struct extent_inode_elem *next;
32
};
33
34
static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
35
struct btrfs_file_extent_item *fi,
36
u64 extent_item_pos,
37
struct extent_inode_elem **eie)
38
{
39
u64 offset = 0;
40
struct extent_inode_elem *e;
41
42
if (!btrfs_file_extent_compression(eb, fi) &&
43
!btrfs_file_extent_encryption(eb, fi) &&
44
!btrfs_file_extent_other_encoding(eb, fi)) {
45
u64 data_offset;
46
u64 data_len;
47
48
data_offset = btrfs_file_extent_offset(eb, fi);
49
data_len = btrfs_file_extent_num_bytes(eb, fi);
50
51
if (extent_item_pos < data_offset ||
52
extent_item_pos >= data_offset + data_len)
53
return 1;
54
offset = extent_item_pos - data_offset;
55
}
56
57
e = kmalloc(sizeof(*e), GFP_NOFS);
58
if (!e)
59
return -ENOMEM;
60
61
e->next = *eie;
62
e->inum = key->objectid;
63
e->offset = key->offset + offset;
64
*eie = e;
65
66
return 0;
67
}
68
69
static void free_inode_elem_list(struct extent_inode_elem *eie)
70
{
71
struct extent_inode_elem *eie_next;
72
73
for (; eie; eie = eie_next) {
74
eie_next = eie->next;
75
kfree(eie);
76
}
77
}
78
79
static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
80
u64 extent_item_pos,
81
struct extent_inode_elem **eie)
82
{
83
u64 disk_byte;
84
struct btrfs_key key;
85
struct btrfs_file_extent_item *fi;
86
int slot;
87
int nritems;
88
int extent_type;
89
int ret;
90
91
/*
92
* from the shared data ref, we only have the leaf but we need
93
* the key. thus, we must look into all items and see that we
94
* find one (some) with a reference to our extent item.
95
*/
96
nritems = btrfs_header_nritems(eb);
97
for (slot = 0; slot < nritems; ++slot) {
98
btrfs_item_key_to_cpu(eb, &key, slot);
99
if (key.type != BTRFS_EXTENT_DATA_KEY)
100
continue;
101
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
102
extent_type = btrfs_file_extent_type(eb, fi);
103
if (extent_type == BTRFS_FILE_EXTENT_INLINE)
104
continue;
105
/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
106
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
107
if (disk_byte != wanted_disk_byte)
108
continue;
109
110
ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
111
if (ret < 0)
112
return ret;
113
}
114
115
return 0;
116
}
117
118
/*
119
* this structure records all encountered refs on the way up to the root
120
*/
121
struct __prelim_ref {
122
struct list_head list;
123
u64 root_id;
124
struct btrfs_key key_for_search;
125
int level;
126
int count;
127
struct extent_inode_elem *inode_list;
128
u64 parent;
129
u64 wanted_disk_byte;
130
};
131
132
/*
133
* the rules for all callers of this function are:
134
* - obtaining the parent is the goal
135
* - if you add a key, you must know that it is a correct key
136
* - if you cannot add the parent or a correct key, then we will look into the
137
* block later to set a correct key
138
*
139
* delayed refs
140
* ============
141
* backref type | shared | indirect | shared | indirect
142
* information | tree | tree | data | data
143
* --------------------+--------+----------+--------+----------
144
* parent logical | y | - | - | -
145
* key to resolve | - | y | y | y
146
* tree block logical | - | - | - | -
147
* root for resolving | y | y | y | y
148
*
149
* - column 1: we've the parent -> done
150
* - column 2, 3, 4: we use the key to find the parent
151
*
152
* on disk refs (inline or keyed)
153
* ==============================
154
* backref type | shared | indirect | shared | indirect
155
* information | tree | tree | data | data
156
* --------------------+--------+----------+--------+----------
157
* parent logical | y | - | y | -
158
* key to resolve | - | - | - | y
159
* tree block logical | y | y | y | y
160
* root for resolving | - | y | y | y
161
*
162
* - column 1, 3: we've the parent -> done
163
* - column 2: we take the first key from the block to find the parent
164
* (see __add_missing_keys)
165
* - column 4: we use the key to find the parent
166
*
167
* additional information that's available but not required to find the parent
168
* block might help in merging entries to gain some speed.
169
*/
170
171
static int __add_prelim_ref(struct list_head *head, u64 root_id,
172
struct btrfs_key *key, int level,
173
u64 parent, u64 wanted_disk_byte, int count,
174
gfp_t gfp_mask)
175
{
176
struct __prelim_ref *ref;
177
178
if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
179
return 0;
180
181
ref = kmalloc(sizeof(*ref), gfp_mask);
182
if (!ref)
183
return -ENOMEM;
184
185
ref->root_id = root_id;
186
if (key)
187
ref->key_for_search = *key;
188
else
189
memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
190
191
ref->inode_list = NULL;
192
ref->level = level;
193
ref->count = count;
194
ref->parent = parent;
195
ref->wanted_disk_byte = wanted_disk_byte;
196
list_add_tail(&ref->list, head);
197
198
return 0;
199
}
200
201
static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
202
struct ulist *parents, struct __prelim_ref *ref,
203
int level, u64 time_seq, const u64 *extent_item_pos,
204
u64 total_refs)
205
{
206
int ret = 0;
207
int slot;
208
struct extent_buffer *eb;
209
struct btrfs_key key;
210
struct btrfs_key *key_for_search = &ref->key_for_search;
211
struct btrfs_file_extent_item *fi;
212
struct extent_inode_elem *eie = NULL, *old = NULL;
213
u64 disk_byte;
214
u64 wanted_disk_byte = ref->wanted_disk_byte;
215
u64 count = 0;
216
217
if (level != 0) {
218
eb = path->nodes[level];
219
ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
220
if (ret < 0)
221
return ret;
222
return 0;
223
}
224
225
/*
226
* We normally enter this function with the path already pointing to
227
* the first item to check. But sometimes, we may enter it with
228
* slot==nritems. In that case, go to the next leaf before we continue.
229
*/
230
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
231
ret = btrfs_next_leaf(root, path);
232
233
while (!ret && count < total_refs) {
234
eb = path->nodes[0];
235
slot = path->slots[0];
236
237
btrfs_item_key_to_cpu(eb, &key, slot);
238
239
if (key.objectid != key_for_search->objectid ||
240
key.type != BTRFS_EXTENT_DATA_KEY)
241
break;
242
243
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
244
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
245
246
if (disk_byte == wanted_disk_byte) {
247
eie = NULL;
248
old = NULL;
249
count++;
250
if (extent_item_pos) {
251
ret = check_extent_in_eb(&key, eb, fi,
252
*extent_item_pos,
253
&eie);
254
if (ret < 0)
255
break;
256
}
257
if (ret > 0)
258
goto next;
259
ret = ulist_add_merge_ptr(parents, eb->start,
260
eie, (void **)&old, GFP_NOFS);
261
if (ret < 0)
262
break;
263
if (!ret && extent_item_pos) {
264
while (old->next)
265
old = old->next;
266
old->next = eie;
267
}
268
eie = NULL;
269
}
270
next:
271
ret = btrfs_next_item(root, path);
272
}
273
274
if (ret > 0)
275
ret = 0;
276
else if (ret < 0)
277
free_inode_elem_list(eie);
278
return ret;
279
}
280
281
/*
282
* resolve an indirect backref in the form (root_id, key, level)
283
* to a logical address
284
*/
285
static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
286
struct btrfs_path *path, u64 time_seq,
287
struct __prelim_ref *ref,
288
struct ulist *parents,
289
const u64 *extent_item_pos, u64 total_refs)
290
{
291
struct btrfs_root *root;
292
struct btrfs_key root_key;
293
struct extent_buffer *eb;
294
int ret = 0;
295
int root_level;
296
int level = ref->level;
297
298
root_key.objectid = ref->root_id;
299
root_key.type = BTRFS_ROOT_ITEM_KEY;
300
root_key.offset = (u64)-1;
301
302
root = btrfs_read_fs_root(fs_info, &root_key);
303
if (IS_ERR(root)) {
304
ret = PTR_ERR(root);
305
goto out;
306
}
307
308
root_level = btrfs_root_level(&root->root_item);
309
310
if (root_level + 1 == level)
311
goto out;
312
313
path->lowest_level = level;
314
ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path, 0, 0);
315
316
pr_debug("search slot in root %llu (level %d, ref count %d) returned "
317
"%d for key (%llu %u %llu)\n",
318
ref->root_id, level, ref->count, ret,
319
ref->key_for_search.objectid, ref->key_for_search.type,
320
ref->key_for_search.offset);
321
if (ret < 0)
322
goto out;
323
324
eb = path->nodes[level];
325
while (!eb) {
326
WARN_ON(!level);
327
if (!level) {
328
ret = 1;
329
goto out;
330
}
331
level--;
332
eb = path->nodes[level];
333
}
334
335
ret = add_all_parents(root, path, parents, ref, level, time_seq,
336
extent_item_pos, total_refs);
337
out:
338
path->lowest_level = 0;
339
btrfs_release_path(path);
340
return ret;
341
}
342
343
/*
344
* resolve all indirect backrefs from the list
345
*/
346
static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
347
struct btrfs_path *path, u64 time_seq,
348
struct list_head *head,
349
const u64 *extent_item_pos, u64 total_refs)
350
{
351
int err;
352
int ret = 0;
353
struct __prelim_ref *ref;
354
struct __prelim_ref *ref_safe;
355
struct __prelim_ref *new_ref;
356
struct ulist *parents;
357
struct ulist_node *node;
358
struct ulist_iterator uiter;
359
360
parents = ulist_alloc(GFP_NOFS);
361
if (!parents)
362
return -ENOMEM;
363
364
/*
365
* _safe allows us to insert directly after the current item without
366
* iterating over the newly inserted items.
367
* we're also allowed to re-assign ref during iteration.
368
*/
369
list_for_each_entry_safe(ref, ref_safe, head, list) {
370
if (ref->parent) /* already direct */
371
continue;
372
if (ref->count == 0)
373
continue;
374
err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
375
parents, extent_item_pos,
376
total_refs);
377
/*
378
* we can only tolerate ENOENT,otherwise,we should catch error
379
* and return directly.
380
*/
381
if (err == -ENOENT) {
382
continue;
383
} else if (err) {
384
ret = err;
385
goto out;
386
}
387
388
/* we put the first parent into the ref at hand */
389
ULIST_ITER_INIT(&uiter);
390
node = ulist_next(parents, &uiter);
391
ref->parent = node ? node->val : 0;
392
ref->inode_list = node ?
393
(struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
394
395
/* additional parents require new refs being added here */
396
while ((node = ulist_next(parents, &uiter))) {
397
new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
398
if (!new_ref) {
399
ret = -ENOMEM;
400
goto out;
401
}
402
memcpy(new_ref, ref, sizeof(*ref));
403
new_ref->parent = node->val;
404
new_ref->inode_list = (struct extent_inode_elem *)
405
(uintptr_t)node->aux;
406
list_add(&new_ref->list, &ref->list);
407
}
408
ulist_reinit(parents);
409
}
410
out:
411
ulist_free(parents);
412
return ret;
413
}
414
415
static inline int ref_for_same_block(struct __prelim_ref *ref1,
416
struct __prelim_ref *ref2)
417
{
418
if (ref1->level != ref2->level)
419
return 0;
420
if (ref1->root_id != ref2->root_id)
421
return 0;
422
if (ref1->key_for_search.type != ref2->key_for_search.type)
423
return 0;
424
if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
425
return 0;
426
if (ref1->key_for_search.offset != ref2->key_for_search.offset)
427
return 0;
428
if (ref1->parent != ref2->parent)
429
return 0;
430
431
return 1;
432
}
433
434
/*
435
* read tree blocks and add keys where required.
436
*/
437
static int __add_missing_keys(struct btrfs_fs_info *fs_info,
438
struct list_head *head)
439
{
440
struct list_head *pos;
441
struct extent_buffer *eb;
442
443
list_for_each(pos, head) {
444
struct __prelim_ref *ref;
445
ref = list_entry(pos, struct __prelim_ref, list);
446
447
if (ref->parent)
448
continue;
449
if (ref->key_for_search.type)
450
continue;
451
BUG_ON(!ref->wanted_disk_byte);
452
eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
453
fs_info->tree_root->leafsize, 0);
454
if (!eb || !extent_buffer_uptodate(eb)) {
455
free_extent_buffer(eb);
456
return -EIO;
457
}
458
if (btrfs_header_level(eb) == 0)
459
btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
460
else
461
btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
462
free_extent_buffer(eb);
463
}
464
return 0;
465
}
466
467
/*
468
* merge two lists of backrefs and adjust counts accordingly
469
*
470
* mode = 1: merge identical keys, if key is set
471
* FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
472
* additionally, we could even add a key range for the blocks we
473
* looked into to merge even more (-> replace unresolved refs by those
474
* having a parent).
475
* mode = 2: merge identical parents
476
*/
477
static void __merge_refs(struct list_head *head, int mode)
478
{
479
struct list_head *pos1;
480
481
list_for_each(pos1, head) {
482
struct list_head *n2;
483
struct list_head *pos2;
484
struct __prelim_ref *ref1;
485
486
ref1 = list_entry(pos1, struct __prelim_ref, list);
487
488
for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
489
pos2 = n2, n2 = pos2->next) {
490
struct __prelim_ref *ref2;
491
struct __prelim_ref *xchg;
492
struct extent_inode_elem *eie;
493
494
ref2 = list_entry(pos2, struct __prelim_ref, list);
495
496
if (mode == 1) {
497
if (!ref_for_same_block(ref1, ref2))
498
continue;
499
if (!ref1->parent && ref2->parent) {
500
xchg = ref1;
501
ref1 = ref2;
502
ref2 = xchg;
503
}
504
} else {
505
if (ref1->parent != ref2->parent)
506
continue;
507
}
508
509
eie = ref1->inode_list;
510
while (eie && eie->next)
511
eie = eie->next;
512
if (eie)
513
eie->next = ref2->inode_list;
514
else
515
ref1->inode_list = ref2->inode_list;
516
ref1->count += ref2->count;
517
518
list_del(&ref2->list);
519
kfree(ref2);
520
}
521
522
}
523
}
524
525
/*
526
* add all inline backrefs for bytenr to the list
527
*/
528
static int __add_inline_refs(struct btrfs_fs_info *fs_info,
529
struct btrfs_path *path, u64 bytenr,
530
int *info_level, struct list_head *prefs,
531
u64 *total_refs)
532
{
533
int ret = 0;
534
int slot;
535
struct extent_buffer *leaf;
536
struct btrfs_key key;
537
struct btrfs_key found_key;
538
unsigned long ptr;
539
unsigned long end;
540
struct btrfs_extent_item *ei;
541
u64 flags;
542
u64 item_size;
543
544
/*
545
* enumerate all inline refs
546
*/
547
leaf = path->nodes[0];
548
slot = path->slots[0];
549
550
item_size = btrfs_item_size_nr(leaf, slot);
551
BUG_ON(item_size < sizeof(*ei));
552
553
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
554
flags = btrfs_extent_flags(leaf, ei);
555
*total_refs += btrfs_extent_refs(leaf, ei);
556
btrfs_item_key_to_cpu(leaf, &found_key, slot);
557
558
ptr = (unsigned long)(ei + 1);
559
end = (unsigned long)ei + item_size;
560
561
if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
562
flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
563
struct btrfs_tree_block_info *info;
564
565
info = (struct btrfs_tree_block_info *)ptr;
566
*info_level = btrfs_tree_block_level(leaf, info);
567
ptr += sizeof(struct btrfs_tree_block_info);
568
BUG_ON(ptr > end);
569
} else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
570
*info_level = found_key.offset;
571
} else {
572
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
573
}
574
575
while (ptr < end) {
576
struct btrfs_extent_inline_ref *iref;
577
u64 offset;
578
int type;
579
580
iref = (struct btrfs_extent_inline_ref *)ptr;
581
type = btrfs_extent_inline_ref_type(leaf, iref);
582
offset = btrfs_extent_inline_ref_offset(leaf, iref);
583
584
switch (type) {
585
case BTRFS_SHARED_BLOCK_REF_KEY:
586
ret = __add_prelim_ref(prefs, 0, NULL,
587
*info_level + 1, offset,
588
bytenr, 1, GFP_NOFS);
589
break;
590
case BTRFS_SHARED_DATA_REF_KEY: {
591
struct btrfs_shared_data_ref *sdref;
592
int count;
593
594
sdref = (struct btrfs_shared_data_ref *)(iref + 1);
595
count = btrfs_shared_data_ref_count(leaf, sdref);
596
ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
597
bytenr, count, GFP_NOFS);
598
break;
599
}
600
case BTRFS_TREE_BLOCK_REF_KEY:
601
ret = __add_prelim_ref(prefs, offset, NULL,
602
*info_level + 1, 0,
603
bytenr, 1, GFP_NOFS);
604
break;
605
case BTRFS_EXTENT_DATA_REF_KEY: {
606
struct btrfs_extent_data_ref *dref;
607
int count;
608
u64 root;
609
610
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
611
count = btrfs_extent_data_ref_count(leaf, dref);
612
key.objectid = btrfs_extent_data_ref_objectid(leaf,
613
dref);
614
key.type = BTRFS_EXTENT_DATA_KEY;
615
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
616
root = btrfs_extent_data_ref_root(leaf, dref);
617
ret = __add_prelim_ref(prefs, root, &key, 0, 0,
618
bytenr, count, GFP_NOFS);
619
break;
620
}
621
default:
622
WARN_ON(1);
623
}
624
if (ret)
625
return ret;
626
ptr += btrfs_extent_inline_ref_size(type);
627
}
628
629
return 0;
630
}
631
632
/*
633
* add all non-inline backrefs for bytenr to the list
634
*/
635
static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
636
struct btrfs_path *path, u64 bytenr,
637
int info_level, struct list_head *prefs)
638
{
639
struct btrfs_root *extent_root = fs_info->extent_root;
640
int ret;
641
int slot;
642
struct extent_buffer *leaf;
643
struct btrfs_key key;
644
645
while (1) {
646
ret = btrfs_next_item(extent_root, path);
647
if (ret < 0)
648
break;
649
if (ret) {
650
ret = 0;
651
break;
652
}
653
654
slot = path->slots[0];
655
leaf = path->nodes[0];
656
btrfs_item_key_to_cpu(leaf, &key, slot);
657
658
if (key.objectid != bytenr)
659
break;
660
if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
661
continue;
662
if (key.type > BTRFS_SHARED_DATA_REF_KEY)
663
break;
664
665
switch (key.type) {
666
case BTRFS_SHARED_BLOCK_REF_KEY:
667
ret = __add_prelim_ref(prefs, 0, NULL,
668
info_level + 1, key.offset,
669
bytenr, 1, GFP_NOFS);
670
break;
671
case BTRFS_SHARED_DATA_REF_KEY: {
672
struct btrfs_shared_data_ref *sdref;
673
int count;
674
675
sdref = btrfs_item_ptr(leaf, slot,
676
struct btrfs_shared_data_ref);
677
count = btrfs_shared_data_ref_count(leaf, sdref);
678
ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
679
bytenr, count, GFP_NOFS);
680
break;
681
}
682
case BTRFS_TREE_BLOCK_REF_KEY:
683
ret = __add_prelim_ref(prefs, key.offset, NULL,
684
info_level + 1, 0,
685
bytenr, 1, GFP_NOFS);
686
break;
687
case BTRFS_EXTENT_DATA_REF_KEY: {
688
struct btrfs_extent_data_ref *dref;
689
int count;
690
u64 root;
691
692
dref = btrfs_item_ptr(leaf, slot,
693
struct btrfs_extent_data_ref);
694
count = btrfs_extent_data_ref_count(leaf, dref);
695
key.objectid = btrfs_extent_data_ref_objectid(leaf,
696
dref);
697
key.type = BTRFS_EXTENT_DATA_KEY;
698
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
699
root = btrfs_extent_data_ref_root(leaf, dref);
700
ret = __add_prelim_ref(prefs, root, &key, 0, 0,
701
bytenr, count, GFP_NOFS);
702
break;
703
}
704
default:
705
WARN_ON(1);
706
}
707
if (ret)
708
return ret;
709
710
}
711
712
return ret;
713
}
714
715
/*
716
* this adds all existing backrefs (inline backrefs, backrefs and delayed
717
* refs) for the given bytenr to the refs list, merges duplicates and resolves
718
* indirect refs to their parent bytenr.
719
* When roots are found, they're added to the roots list
720
*
721
* FIXME some caching might speed things up
722
*/
723
static int find_parent_nodes(struct btrfs_trans_handle *trans,
724
struct btrfs_fs_info *fs_info, u64 bytenr,
725
u64 time_seq, struct ulist *refs,
726
struct ulist *roots, const u64 *extent_item_pos)
727
{
728
struct btrfs_key key;
729
struct btrfs_path *path;
730
int info_level = 0;
731
int ret;
732
struct list_head prefs;
733
struct __prelim_ref *ref;
734
struct extent_inode_elem *eie = NULL;
735
u64 total_refs = 0;
736
737
INIT_LIST_HEAD(&prefs);
738
739
key.objectid = bytenr;
740
key.offset = (u64)-1;
741
if (btrfs_fs_incompat(fs_info,
742
BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA))
743
key.type = BTRFS_METADATA_ITEM_KEY;
744
else
745
key.type = BTRFS_EXTENT_ITEM_KEY;
746
747
path = btrfs_alloc_path();
748
if (!path)
749
return -ENOMEM;
750
751
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
752
if (ret < 0)
753
goto out;
754
BUG_ON(ret == 0);
755
756
if (path->slots[0]) {
757
struct extent_buffer *leaf;
758
int slot;
759
760
path->slots[0]--;
761
leaf = path->nodes[0];
762
slot = path->slots[0];
763
btrfs_item_key_to_cpu(leaf, &key, slot);
764
if (key.objectid == bytenr &&
765
(key.type == BTRFS_EXTENT_ITEM_KEY ||
766
key.type == BTRFS_METADATA_ITEM_KEY)) {
767
ret = __add_inline_refs(fs_info, path, bytenr,
768
&info_level, &prefs,
769
&total_refs);
770
if (ret)
771
goto out;
772
ret = __add_keyed_refs(fs_info, path, bytenr,
773
info_level, &prefs);
774
if (ret)
775
goto out;
776
}
777
}
778
btrfs_release_path(path);
779
780
ret = __add_missing_keys(fs_info, &prefs);
781
if (ret)
782
goto out;
783
784
__merge_refs(&prefs, 1);
785
786
ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
787
extent_item_pos, total_refs);
788
if (ret)
789
goto out;
790
791
__merge_refs(&prefs, 2);
792
793
while (!list_empty(&prefs)) {
794
ref = list_first_entry(&prefs, struct __prelim_ref, list);
795
WARN_ON(ref->count < 0);
796
if (roots && ref->count && ref->root_id && ref->parent == 0) {
797
/* no parent == root of tree */
798
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
799
if (ret < 0)
800
goto out;
801
}
802
if (ref->count && ref->parent) {
803
if (extent_item_pos && !ref->inode_list &&
804
ref->level == 0) {
805
u32 bsz;
806
struct extent_buffer *eb;
807
bsz = btrfs_level_size(fs_info->extent_root,
808
ref->level);
809
eb = read_tree_block(fs_info->extent_root,
810
ref->parent, bsz, 0);
811
if (!eb || !extent_buffer_uptodate(eb)) {
812
free_extent_buffer(eb);
813
ret = -EIO;
814
goto out;
815
}
816
ret = find_extent_in_eb(eb, bytenr,
817
*extent_item_pos, &eie);
818
free_extent_buffer(eb);
819
if (ret < 0)
820
goto out;
821
ref->inode_list = eie;
822
}
823
ret = ulist_add_merge_ptr(refs, ref->parent,
824
ref->inode_list,
825
(void **)&eie, GFP_NOFS);
826
if (ret < 0)
827
goto out;
828
if (!ret && extent_item_pos) {
829
/*
830
* we've recorded that parent, so we must extend
831
* its inode list here
832
*/
833
BUG_ON(!eie);
834
while (eie->next)
835
eie = eie->next;
836
eie->next = ref->inode_list;
837
}
838
eie = NULL;
839
}
840
list_del(&ref->list);
841
kfree(ref);
842
}
843
844
out:
845
btrfs_free_path(path);
846
while (!list_empty(&prefs)) {
847
ref = list_first_entry(&prefs, struct __prelim_ref, list);
848
list_del(&ref->list);
849
kfree(ref);
850
}
851
if (ret < 0)
852
free_inode_elem_list(eie);
853
return ret;
854
}
855
856
static void free_leaf_list(struct ulist *blocks)
857
{
858
struct ulist_node *node = NULL;
859
struct extent_inode_elem *eie;
860
struct ulist_iterator uiter;
861
862
ULIST_ITER_INIT(&uiter);
863
while ((node = ulist_next(blocks, &uiter))) {
864
if (!node->aux)
865
continue;
866
eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
867
free_inode_elem_list(eie);
868
node->aux = 0;
869
}
870
871
ulist_free(blocks);
872
}
873
874
/*
875
* Finds all leafs with a reference to the specified combination of bytenr and
876
* offset. key_list_head will point to a list of corresponding keys (caller must
877
* free each list element). The leafs will be stored in the leafs ulist, which
878
* must be freed with ulist_free.
879
*
880
* returns 0 on success, <0 on error
881
*/
882
static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
883
struct btrfs_fs_info *fs_info, u64 bytenr,
884
u64 time_seq, struct ulist **leafs,
885
const u64 *extent_item_pos)
886
{
887
int ret;
888
889
*leafs = ulist_alloc(GFP_NOFS);
890
if (!*leafs)
891
return -ENOMEM;
892
893
ret = find_parent_nodes(trans, fs_info, bytenr,
894
time_seq, *leafs, NULL, extent_item_pos);
895
if (ret < 0 && ret != -ENOENT) {
896
free_leaf_list(*leafs);
897
return ret;
898
}
899
900
return 0;
901
}
902
903
/*
904
* walk all backrefs for a given extent to find all roots that reference this
905
* extent. Walking a backref means finding all extents that reference this
906
* extent and in turn walk the backrefs of those, too. Naturally this is a
907
* recursive process, but here it is implemented in an iterative fashion: We
908
* find all referencing extents for the extent in question and put them on a
909
* list. In turn, we find all referencing extents for those, further appending
910
* to the list. The way we iterate the list allows adding more elements after
911
* the current while iterating. The process stops when we reach the end of the
912
* list. Found roots are added to the roots list.
913
*
914
* returns 0 on success, < 0 on error.
915
*/
916
static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
917
struct btrfs_fs_info *fs_info, u64 bytenr,
918
u64 time_seq, struct ulist **roots)
919
{
920
struct ulist *tmp;
921
struct ulist_node *node = NULL;
922
struct ulist_iterator uiter;
923
int ret;
924
925
tmp = ulist_alloc(GFP_NOFS);
926
if (!tmp)
927
return -ENOMEM;
928
*roots = ulist_alloc(GFP_NOFS);
929
if (!*roots) {
930
ulist_free(tmp);
931
return -ENOMEM;
932
}
933
934
ULIST_ITER_INIT(&uiter);
935
while (1) {
936
ret = find_parent_nodes(trans, fs_info, bytenr,
937
time_seq, tmp, *roots, NULL);
938
if (ret < 0 && ret != -ENOENT) {
939
ulist_free(tmp);
940
ulist_free(*roots);
941
return ret;
942
}
943
node = ulist_next(tmp, &uiter);
944
if (!node)
945
break;
946
bytenr = node->val;
947
cond_resched();
948
}
949
950
ulist_free(tmp);
951
return 0;
952
}
953
954
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
955
struct btrfs_fs_info *fs_info, u64 bytenr,
956
u64 time_seq, struct ulist **roots)
957
{
958
return __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
959
}
960
961
/*
962
* this makes the path point to (inum INODE_ITEM ioff)
963
*/
964
int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
965
struct btrfs_path *path)
966
{
967
struct btrfs_key key;
968
return btrfs_find_item(fs_root, path, inum, ioff,
969
BTRFS_INODE_ITEM_KEY, &key);
970
}
971
972
static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
973
struct btrfs_path *path,
974
struct btrfs_key *found_key)
975
{
976
return btrfs_find_item(fs_root, path, inum, ioff,
977
BTRFS_INODE_REF_KEY, found_key);
978
}
979
980
int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
981
u64 start_off, struct btrfs_path *path,
982
struct btrfs_inode_extref **ret_extref,
983
u64 *found_off)
984
{
985
int ret, slot;
986
struct btrfs_key key;
987
struct btrfs_key found_key;
988
struct btrfs_inode_extref *extref;
989
struct extent_buffer *leaf;
990
unsigned long ptr;
991
992
key.objectid = inode_objectid;
993
btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
994
key.offset = start_off;
995
996
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
997
if (ret < 0)
998
return ret;
999
1000
while (1) {
1001
leaf = path->nodes[0];
1002
slot = path->slots[0];
1003
if (slot >= btrfs_header_nritems(leaf)) {
1004
/*
1005
* If the item at offset is not found,
1006
* btrfs_search_slot will point us to the slot
1007
* where it should be inserted. In our case
1008
* that will be the slot directly before the
1009
* next INODE_REF_KEY_V2 item. In the case
1010
* that we're pointing to the last slot in a
1011
* leaf, we must move one leaf over.
1012
*/
1013
ret = btrfs_next_leaf(root, path);
1014
if (ret) {
1015
if (ret >= 1)
1016
ret = -ENOENT;
1017
break;
1018
}
1019
continue;
1020
}
1021
1022
btrfs_item_key_to_cpu(leaf, &found_key, slot);
1023
1024
/*
1025
* Check that we're still looking at an extended ref key for
1026
* this particular objectid. If we have different
1027
* objectid or type then there are no more to be found
1028
* in the tree and we can exit.
1029
*/
1030
ret = -ENOENT;
1031
if (found_key.objectid != inode_objectid)
1032
break;
1033
if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
1034
break;
1035
1036
ret = 0;
1037
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1038
extref = (struct btrfs_inode_extref *)ptr;
1039
*ret_extref = extref;
1040
if (found_off)
1041
*found_off = found_key.offset;
1042
break;
1043
}
1044
1045
return ret;
1046
}
1047
1048
/*
1049
* this iterates to turn a name (from iref/extref) into a full filesystem path.
1050
* Elements of the path are separated by '/' and the path is guaranteed to be
1051
* 0-terminated. the path is only given within the current file system.
1052
* Therefore, it never starts with a '/'. the caller is responsible to provide
1053
* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1054
* the start point of the resulting string is returned. this pointer is within
1055
* dest, normally.
1056
* in case the path buffer would overflow, the pointer is decremented further
1057
* as if output was written to the buffer, though no more output is actually
1058
* generated. that way, the caller can determine how much space would be
1059
* required for the path to fit into the buffer. in that case, the returned
1060
* value will be smaller than dest. callers must check this!
1061
*/
1062
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1063
u32 name_len, unsigned long name_off,
1064
struct extent_buffer *eb_in, u64 parent,
1065
char *dest, u32 size)
1066
{
1067
int slot;
1068
u64 next_inum;
1069
int ret;
1070
s64 bytes_left = ((s64)size) - 1;
1071
struct extent_buffer *eb = eb_in;
1072
struct btrfs_key found_key;
1073
struct btrfs_inode_ref *iref;
1074
1075
if (bytes_left >= 0)
1076
dest[bytes_left] = '\0';
1077
1078
while (1) {
1079
bytes_left -= name_len;
1080
if (bytes_left >= 0)
1081
read_extent_buffer(eb, dest + bytes_left,
1082
name_off, name_len);
1083
if (eb != eb_in)
1084
free_extent_buffer(eb);
1085
ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
1086
if (ret > 0)
1087
ret = -ENOENT;
1088
if (ret)
1089
break;
1090
1091
next_inum = found_key.offset;
1092
1093
/* regular exit ahead */
1094
if (parent == next_inum)
1095
break;
1096
1097
slot = path->slots[0];
1098
eb = path->nodes[0];
1099
/* make sure we can use eb after releasing the path */
1100
if (eb != eb_in)
1101
eb->refs++;
1102
btrfs_release_path(path);
1103
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1104
1105
name_len = btrfs_inode_ref_name_len(eb, iref);
1106
name_off = (unsigned long)(iref + 1);
1107
1108
parent = next_inum;
1109
--bytes_left;
1110
if (bytes_left >= 0)
1111
dest[bytes_left] = '/';
1112
}
1113
1114
btrfs_release_path(path);
1115
1116
if (ret)
1117
return ERR_PTR(ret);
1118
1119
return dest + bytes_left;
1120
}
1121
1122
/*
1123
* this makes the path point to (logical EXTENT_ITEM *)
1124
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1125
* tree blocks and <0 on error.
1126
*/
1127
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
1128
struct btrfs_path *path, struct btrfs_key *found_key,
1129
u64 *flags_ret)
1130
{
1131
int ret;
1132
u64 flags;
1133
u64 size = 0;
1134
u32 item_size;
1135
struct extent_buffer *eb;
1136
struct btrfs_extent_item *ei;
1137
struct btrfs_key key;
1138
1139
if (btrfs_fs_incompat(fs_info,
1140
BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA))
1141
key.type = BTRFS_METADATA_ITEM_KEY;
1142
else
1143
key.type = BTRFS_EXTENT_ITEM_KEY;
1144
key.objectid = logical;
1145
key.offset = (u64)-1;
1146
1147
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1148
if (ret < 0)
1149
return ret;
1150
1151
ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1152
if (ret) {
1153
if (ret > 0)
1154
ret = -ENOENT;
1155
return ret;
1156
}
1157
btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
1158
if (found_key->type == BTRFS_METADATA_ITEM_KEY)
1159
size = fs_info->extent_root->leafsize;
1160
else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1161
size = found_key->offset;
1162
1163
if (found_key->objectid > logical ||
1164
found_key->objectid + size <= logical) {
1165
pr_debug("logical %llu is not within any extent\n", logical);
1166
return -ENOENT;
1167
}
1168
1169
eb = path->nodes[0];
1170
item_size = btrfs_item_size_nr(eb, path->slots[0]);
1171
BUG_ON(item_size < sizeof(*ei));
1172
1173
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1174
flags = btrfs_extent_flags(eb, ei);
1175
1176
pr_debug("logical %llu is at position %llu within the extent (%llu "
1177
"EXTENT_ITEM %llu) flags %#llx size %u\n",
1178
logical, logical - found_key->objectid, found_key->objectid,
1179
found_key->offset, flags, item_size);
1180
1181
WARN_ON(!flags_ret);
1182
if (flags_ret) {
1183
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1184
*flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1185
else if (flags & BTRFS_EXTENT_FLAG_DATA)
1186
*flags_ret = BTRFS_EXTENT_FLAG_DATA;
1187
else
1188
BUG_ON(1);
1189
return 0;
1190
}
1191
1192
return -EIO;
1193
}
1194
1195
/*
1196
* helper function to iterate extent inline refs. ptr must point to a 0 value
1197
* for the first call and may be modified. it is used to track state.
1198
* if more refs exist, 0 is returned and the next call to
1199
* __get_extent_inline_ref must pass the modified ptr parameter to get the
1200
* next ref. after the last ref was processed, 1 is returned.
1201
* returns <0 on error
1202
*/
1203
static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1204
struct btrfs_key *key,
1205
struct btrfs_extent_item *ei, u32 item_size,
1206
struct btrfs_extent_inline_ref **out_eiref,
1207
int *out_type)
1208
{
1209
unsigned long end;
1210
u64 flags;
1211
struct btrfs_tree_block_info *info;
1212
1213
if (!*ptr) {
1214
/* first call */
1215
flags = btrfs_extent_flags(eb, ei);
1216
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1217
if (key->type == BTRFS_METADATA_ITEM_KEY) {
1218
/* a skinny metadata extent */
1219
*out_eiref =
1220
(struct btrfs_extent_inline_ref *)(ei + 1);
1221
} else {
1222
WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1223
info = (struct btrfs_tree_block_info *)(ei + 1);
1224
*out_eiref =
1225
(struct btrfs_extent_inline_ref *)(info + 1);
1226
}
1227
} else {
1228
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1229
}
1230
*ptr = (unsigned long)*out_eiref;
1231
if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
1232
return -ENOENT;
1233
}
1234
1235
end = (unsigned long)ei + item_size;
1236
*out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
1237
*out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1238
1239
*ptr += btrfs_extent_inline_ref_size(*out_type);
1240
WARN_ON(*ptr > end);
1241
if (*ptr == end)
1242
return 1; /* last */
1243
1244
return 0;
1245
}
1246
1247
/*
1248
* reads the tree block backref for an extent. tree level and root are returned
1249
* through out_level and out_root. ptr must point to a 0 value for the first
1250
* call and may be modified (see __get_extent_inline_ref comment).
1251
* returns 0 if data was provided, 1 if there was no more data to provide or
1252
* <0 on error.
1253
*/
1254
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1255
struct btrfs_key *key, struct btrfs_extent_item *ei,
1256
u32 item_size, u64 *out_root, u8 *out_level)
1257
{
1258
int ret;
1259
int type;
1260
struct btrfs_tree_block_info *info;
1261
struct btrfs_extent_inline_ref *eiref;
1262
1263
if (*ptr == (unsigned long)-1)
1264
return 1;
1265
1266
while (1) {
1267
ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1268
&eiref, &type);
1269
if (ret < 0)
1270
return ret;
1271
1272
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1273
type == BTRFS_SHARED_BLOCK_REF_KEY)
1274
break;
1275
1276
if (ret == 1)
1277
return 1;
1278
}
1279
1280
/* we can treat both ref types equally here */
1281
info = (struct btrfs_tree_block_info *)(ei + 1);
1282
*out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1283
*out_level = btrfs_tree_block_level(eb, info);
1284
1285
if (ret == 1)
1286
*ptr = (unsigned long)-1;
1287
1288
return 0;
1289
}
1290
1291
static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1292
u64 root, u64 extent_item_objectid,
1293
iterate_extent_inodes_t *iterate, void *ctx)
1294
{
1295
struct extent_inode_elem *eie;
1296
int ret = 0;
1297
1298
for (eie = inode_list; eie; eie = eie->next) {
1299
pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1300
"root %llu\n", extent_item_objectid,
1301
eie->inum, eie->offset, root);
1302
ret = iterate(eie->inum, eie->offset, root, ctx);
1303
if (ret) {
1304
pr_debug("stopping iteration for %llu due to ret=%d\n",
1305
extent_item_objectid, ret);
1306
break;
1307
}
1308
}
1309
1310
return ret;
1311
}
1312
1313
/*
1314
* calls iterate() for every inode that references the extent identified by
1315
* the given parameters.
1316
* when the iterator function returns a non-zero value, iteration stops.
1317
*/
1318
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
1319
u64 extent_item_objectid, u64 extent_item_pos,
1320
int search_commit_root,
1321
iterate_extent_inodes_t *iterate, void *ctx)
1322
{
1323
int ret;
1324
struct btrfs_trans_handle *trans = NULL;
1325
struct ulist *refs = NULL;
1326
struct ulist *roots = NULL;
1327
struct ulist_node *ref_node = NULL;
1328
struct ulist_node *root_node = NULL;
1329
struct ulist_iterator ref_uiter;
1330
struct ulist_iterator root_uiter;
1331
1332
pr_debug("resolving all inodes for extent %llu\n",
1333
extent_item_objectid);
1334
1335
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
1336
0, &refs, &extent_item_pos);
1337
if (ret)
1338
goto out;
1339
1340
ULIST_ITER_INIT(&ref_uiter);
1341
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
1342
ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
1343
0, &roots);
1344
if (ret)
1345
break;
1346
ULIST_ITER_INIT(&root_uiter);
1347
while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
1348
pr_debug("root %llu references leaf %llu, data list "
1349
"%#llx\n", root_node->val, ref_node->val,
1350
ref_node->aux);
1351
ret = iterate_leaf_refs((struct extent_inode_elem *)
1352
(uintptr_t)ref_node->aux,
1353
root_node->val,
1354
extent_item_objectid,
1355
iterate, ctx);
1356
}
1357
ulist_free(roots);
1358
}
1359
1360
free_leaf_list(refs);
1361
out:
1362
return ret;
1363
}
1364
1365
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1366
struct btrfs_path *path,
1367
iterate_extent_inodes_t *iterate, void *ctx)
1368
{
1369
int ret;
1370
u64 extent_item_pos;
1371
u64 flags = 0;
1372
struct btrfs_key found_key;
1373
int search_commit_root = 0;
1374
1375
ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
1376
btrfs_release_path(path);
1377
if (ret < 0)
1378
return ret;
1379
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1380
return -EINVAL;
1381
1382
extent_item_pos = logical - found_key.objectid;
1383
ret = iterate_extent_inodes(fs_info, found_key.objectid,
1384
extent_item_pos, search_commit_root,
1385
iterate, ctx);
1386
1387
return ret;
1388
}
1389
1390
typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1391
struct extent_buffer *eb, void *ctx);
1392
1393
static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1394
struct btrfs_path *path,
1395
iterate_irefs_t *iterate, void *ctx)
1396
{
1397
int ret = 0;
1398
int slot;
1399
u32 cur;
1400
u32 len;
1401
u32 name_len;
1402
u64 parent = 0;
1403
int found = 0;
1404
struct extent_buffer *eb;
1405
struct btrfs_item *item;
1406
struct btrfs_inode_ref *iref;
1407
struct btrfs_key found_key;
1408
1409
while (!ret) {
1410
ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
1411
&found_key);
1412
if (ret < 0)
1413
break;
1414
if (ret) {
1415
ret = found ? 0 : -ENOENT;
1416
break;
1417
}
1418
++found;
1419
1420
parent = found_key.offset;
1421
slot = path->slots[0];
1422
eb = btrfs_clone_extent_buffer(path->nodes[0]);
1423
if (!eb) {
1424
ret = -ENOMEM;
1425
break;
1426
}
1427
extent_buffer_get(eb);
1428
btrfs_release_path(path);
1429
1430
item = btrfs_item_nr(slot);
1431
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1432
1433
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1434
name_len = btrfs_inode_ref_name_len(eb, iref);
1435
/* path must be released before calling iterate()! */
1436
pr_debug("following ref at offset %u for inode %llu in "
1437
"tree %llu\n", cur, found_key.objectid,
1438
fs_root->objectid);
1439
ret = iterate(parent, name_len,
1440
(unsigned long)(iref + 1), eb, ctx);
1441
if (ret)
1442
break;
1443
len = sizeof(*iref) + name_len;
1444
iref = (struct btrfs_inode_ref *)((char *)iref + len);
1445
}
1446
free_extent_buffer(eb);
1447
}
1448
1449
btrfs_release_path(path);
1450
1451
return ret;
1452
}
1453
1454
static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1455
struct btrfs_path *path,
1456
iterate_irefs_t *iterate, void *ctx)
1457
{
1458
int ret;
1459
int slot;
1460
u64 offset = 0;
1461
u64 parent;
1462
int found = 0;
1463
struct extent_buffer *eb;
1464
struct btrfs_inode_extref *extref;
1465
struct extent_buffer *leaf;
1466
u32 item_size;
1467
u32 cur_offset;
1468
unsigned long ptr;
1469
1470
while (1) {
1471
ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1472
&offset);
1473
if (ret < 0)
1474
break;
1475
if (ret) {
1476
ret = found ? 0 : -ENOENT;
1477
break;
1478
}
1479
++found;
1480
1481
slot = path->slots[0];
1482
eb = btrfs_clone_extent_buffer(path->nodes[0]);
1483
if (!eb) {
1484
ret = -ENOMEM;
1485
break;
1486
}
1487
extent_buffer_get(eb);
1488
1489
btrfs_release_path(path);
1490
1491
leaf = path->nodes[0];
1492
item_size = btrfs_item_size_nr(leaf, slot);
1493
ptr = btrfs_item_ptr_offset(leaf, slot);
1494
cur_offset = 0;
1495
1496
while (cur_offset < item_size) {
1497
u32 name_len;
1498
1499
extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1500
parent = btrfs_inode_extref_parent(eb, extref);
1501
name_len = btrfs_inode_extref_name_len(eb, extref);
1502
ret = iterate(parent, name_len,
1503
(unsigned long)&extref->name, eb, ctx);
1504
if (ret)
1505
break;
1506
1507
cur_offset += btrfs_inode_extref_name_len(leaf, extref);
1508
cur_offset += sizeof(*extref);
1509
}
1510
free_extent_buffer(eb);
1511
1512
offset++;
1513
}
1514
1515
btrfs_release_path(path);
1516
1517
return ret;
1518
}
1519
1520
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1521
struct btrfs_path *path, iterate_irefs_t *iterate,
1522
void *ctx)
1523
{
1524
int ret;
1525
int found_refs = 0;
1526
1527
ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1528
if (!ret)
1529
++found_refs;
1530
else if (ret != -ENOENT)
1531
return ret;
1532
1533
ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1534
if (ret == -ENOENT && found_refs)
1535
return 0;
1536
1537
return ret;
1538
}
1539
1540
/*
1541
* returns 0 if the path could be dumped (probably truncated)
1542
* returns <0 in case of an error
1543
*/
1544
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1545
struct extent_buffer *eb, void *ctx)
1546
{
1547
struct inode_fs_paths *ipath = ctx;
1548
char *fspath;
1549
char *fspath_min;
1550
int i = ipath->fspath->elem_cnt;
1551
const int s_ptr = sizeof(char *);
1552
u32 bytes_left;
1553
1554
bytes_left = ipath->fspath->bytes_left > s_ptr ?
1555
ipath->fspath->bytes_left - s_ptr : 0;
1556
1557
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
1558
fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1559
name_off, eb, inum, fspath_min, bytes_left);
1560
if (IS_ERR(fspath))
1561
return PTR_ERR(fspath);
1562
1563
if (fspath > fspath_min) {
1564
ipath->fspath->val[i] = (u64)(unsigned long)fspath;
1565
++ipath->fspath->elem_cnt;
1566
ipath->fspath->bytes_left = fspath - fspath_min;
1567
} else {
1568
++ipath->fspath->elem_missed;
1569
ipath->fspath->bytes_missing += fspath_min - fspath;
1570
ipath->fspath->bytes_left = 0;
1571
}
1572
1573
return 0;
1574
}
1575
1576
/*
1577
* this dumps all file system paths to the inode into the ipath struct, provided
1578
* is has been created large enough. each path is zero-terminated and accessed
1579
* from ipath->fspath->val[i].
1580
* when it returns, there are ipath->fspath->elem_cnt number of paths available
1581
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1582
* number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1583
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1584
* have been needed to return all paths.
1585
*/
1586
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1587
{
1588
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
1589
inode_to_path, ipath);
1590
}
1591
1592
struct btrfs_data_container *init_data_container(u32 total_bytes)
1593
{
1594
struct btrfs_data_container *data;
1595
size_t alloc_bytes;
1596
1597
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
1598
data = vmalloc(alloc_bytes);
1599
if (!data)
1600
return ERR_PTR(-ENOMEM);
1601
1602
if (total_bytes >= sizeof(*data)) {
1603
data->bytes_left = total_bytes - sizeof(*data);
1604
data->bytes_missing = 0;
1605
} else {
1606
data->bytes_missing = sizeof(*data) - total_bytes;
1607
data->bytes_left = 0;
1608
}
1609
1610
data->elem_cnt = 0;
1611
data->elem_missed = 0;
1612
1613
return data;
1614
}
1615
1616
/*
1617
* allocates space to return multiple file system paths for an inode.
1618
* total_bytes to allocate are passed, note that space usable for actual path
1619
* information will be total_bytes - sizeof(struct inode_fs_paths).
1620
* the returned pointer must be freed with free_ipath() in the end.
1621
*/
1622
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1623
struct btrfs_path *path)
1624
{
1625
struct inode_fs_paths *ifp;
1626
struct btrfs_data_container *fspath;
1627
1628
fspath = init_data_container(total_bytes);
1629
if (IS_ERR(fspath))
1630
return (void *)fspath;
1631
1632
ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1633
if (!ifp) {
1634
kfree(fspath);
1635
return ERR_PTR(-ENOMEM);
1636
}
1637
1638
ifp->btrfs_path = path;
1639
ifp->fspath = fspath;
1640
ifp->fs_root = fs_root;
1641
1642
return ifp;
1643
}
1644
1645
void free_ipath(struct inode_fs_paths *ipath)
1646
{
1647
if (!ipath)
1648
return;
1649
vfree(ipath->fspath);
1650
kfree(ipath);
1651
}
Loggerhead is a web-based interface for Breezy
Version: 2.0.1