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1/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-cache-metadata.h"
8
9#include "persistent-data/dm-array.h"
10#include "persistent-data/dm-bitset.h"
11#include "persistent-data/dm-space-map.h"
12#include "persistent-data/dm-space-map-disk.h"
13#include "persistent-data/dm-transaction-manager.h"
14
15#include <linux/device-mapper.h>
16
17/*----------------------------------------------------------------*/
18
19#define DM_MSG_PREFIX "cache metadata"
20
21#define CACHE_SUPERBLOCK_MAGIC 06142003
22#define CACHE_SUPERBLOCK_LOCATION 0
23
24/*
25 * defines a range of metadata versions that this module can handle.
26 */
27#define MIN_CACHE_VERSION 1
28#define MAX_CACHE_VERSION 1
29
30#define CACHE_METADATA_CACHE_SIZE 64
31
32/*
33 * 3 for btree insert +
34 * 2 for btree lookup used within space map
35 */
36#define CACHE_MAX_CONCURRENT_LOCKS 5
37#define SPACE_MAP_ROOT_SIZE 128
38
39enum superblock_flag_bits {
40 /* for spotting crashes that would invalidate the dirty bitset */
41 CLEAN_SHUTDOWN,
42 /* metadata must be checked using the tools */
43 NEEDS_CHECK,
44};
45
46/*
47 * Each mapping from cache block -> origin block carries a set of flags.
48 */
49enum mapping_bits {
50 /*
51 * A valid mapping. Because we're using an array we clear this
52 * flag for an non existant mapping.
53 */
54 M_VALID = 1,
55
56 /*
57 * The data on the cache is different from that on the origin.
58 */
59 M_DIRTY = 2
60};
61
62struct cache_disk_superblock {
63 __le32 csum;
64 __le32 flags;
65 __le64 blocknr;
66
67 __u8 uuid[16];
68 __le64 magic;
69 __le32 version;
70
71 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
72 __le32 policy_hint_size;
73
74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
75 __le64 mapping_root;
76 __le64 hint_root;
77
78 __le64 discard_root;
79 __le64 discard_block_size;
80 __le64 discard_nr_blocks;
81
82 __le32 data_block_size;
83 __le32 metadata_block_size;
84 __le32 cache_blocks;
85
86 __le32 compat_flags;
87 __le32 compat_ro_flags;
88 __le32 incompat_flags;
89
90 __le32 read_hits;
91 __le32 read_misses;
92 __le32 write_hits;
93 __le32 write_misses;
94
95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
96} __packed;
97
98struct dm_cache_metadata {
99 atomic_t ref_count;
100 struct list_head list;
101
102 struct block_device *bdev;
103 struct dm_block_manager *bm;
104 struct dm_space_map *metadata_sm;
105 struct dm_transaction_manager *tm;
106
107 struct dm_array_info info;
108 struct dm_array_info hint_info;
109 struct dm_disk_bitset discard_info;
110
111 struct rw_semaphore root_lock;
112 unsigned long flags;
113 dm_block_t root;
114 dm_block_t hint_root;
115 dm_block_t discard_root;
116
117 sector_t discard_block_size;
118 dm_dblock_t discard_nr_blocks;
119
120 sector_t data_block_size;
121 dm_cblock_t cache_blocks;
122 bool changed:1;
123 bool clean_when_opened:1;
124
125 char policy_name[CACHE_POLICY_NAME_SIZE];
126 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
127 size_t policy_hint_size;
128 struct dm_cache_statistics stats;
129
130 /*
131 * Reading the space map root can fail, so we read it into this
132 * buffer before the superblock is locked and updated.
133 */
134 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
135
136 /*
137 * Set if a transaction has to be aborted but the attempt to roll
138 * back to the previous (good) transaction failed. The only
139 * metadata operation permissible in this state is the closing of
140 * the device.
141 */
142 bool fail_io:1;
143};
144
145/*-------------------------------------------------------------------
146 * superblock validator
147 *-----------------------------------------------------------------*/
148
149#define SUPERBLOCK_CSUM_XOR 9031977
150
151static void sb_prepare_for_write(struct dm_block_validator *v,
152 struct dm_block *b,
153 size_t sb_block_size)
154{
155 struct cache_disk_superblock *disk_super = dm_block_data(b);
156
157 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
158 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
159 sb_block_size - sizeof(__le32),
160 SUPERBLOCK_CSUM_XOR));
161}
162
163static int check_metadata_version(struct cache_disk_superblock *disk_super)
164{
165 uint32_t metadata_version = le32_to_cpu(disk_super->version);
166 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
167 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
168 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
169 return -EINVAL;
170 }
171
172 return 0;
173}
174
175static int sb_check(struct dm_block_validator *v,
176 struct dm_block *b,
177 size_t sb_block_size)
178{
179 struct cache_disk_superblock *disk_super = dm_block_data(b);
180 __le32 csum_le;
181
182 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
183 DMERR("sb_check failed: blocknr %llu: wanted %llu",
184 le64_to_cpu(disk_super->blocknr),
185 (unsigned long long)dm_block_location(b));
186 return -ENOTBLK;
187 }
188
189 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
190 DMERR("sb_check failed: magic %llu: wanted %llu",
191 le64_to_cpu(disk_super->magic),
192 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
193 return -EILSEQ;
194 }
195
196 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
197 sb_block_size - sizeof(__le32),
198 SUPERBLOCK_CSUM_XOR));
199 if (csum_le != disk_super->csum) {
200 DMERR("sb_check failed: csum %u: wanted %u",
201 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
202 return -EILSEQ;
203 }
204
205 return check_metadata_version(disk_super);
206}
207
208static struct dm_block_validator sb_validator = {
209 .name = "superblock",
210 .prepare_for_write = sb_prepare_for_write,
211 .check = sb_check
212};
213
214/*----------------------------------------------------------------*/
215
216static int superblock_read_lock(struct dm_cache_metadata *cmd,
217 struct dm_block **sblock)
218{
219 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
220 &sb_validator, sblock);
221}
222
223static int superblock_lock_zero(struct dm_cache_metadata *cmd,
224 struct dm_block **sblock)
225{
226 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
227 &sb_validator, sblock);
228}
229
230static int superblock_lock(struct dm_cache_metadata *cmd,
231 struct dm_block **sblock)
232{
233 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
234 &sb_validator, sblock);
235}
236
237/*----------------------------------------------------------------*/
238
239static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
240{
241 int r;
242 unsigned i;
243 struct dm_block *b;
244 __le64 *data_le, zero = cpu_to_le64(0);
245 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
246
247 /*
248 * We can't use a validator here - it may be all zeroes.
249 */
250 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
251 if (r)
252 return r;
253
254 data_le = dm_block_data(b);
255 *result = true;
256 for (i = 0; i < sb_block_size; i++) {
257 if (data_le[i] != zero) {
258 *result = false;
259 break;
260 }
261 }
262
263 dm_bm_unlock(b);
264
265 return 0;
266}
267
268static void __setup_mapping_info(struct dm_cache_metadata *cmd)
269{
270 struct dm_btree_value_type vt;
271
272 vt.context = NULL;
273 vt.size = sizeof(__le64);
274 vt.inc = NULL;
275 vt.dec = NULL;
276 vt.equal = NULL;
277 dm_array_info_init(&cmd->info, cmd->tm, &vt);
278
279 if (cmd->policy_hint_size) {
280 vt.size = sizeof(__le32);
281 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
282 }
283}
284
285static int __save_sm_root(struct dm_cache_metadata *cmd)
286{
287 int r;
288 size_t metadata_len;
289
290 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
291 if (r < 0)
292 return r;
293
294 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
295 metadata_len);
296}
297
298static void __copy_sm_root(struct dm_cache_metadata *cmd,
299 struct cache_disk_superblock *disk_super)
300{
301 memcpy(&disk_super->metadata_space_map_root,
302 &cmd->metadata_space_map_root,
303 sizeof(cmd->metadata_space_map_root));
304}
305
306static int __write_initial_superblock(struct dm_cache_metadata *cmd)
307{
308 int r;
309 struct dm_block *sblock;
310 struct cache_disk_superblock *disk_super;
311 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
312
313 /* FIXME: see if we can lose the max sectors limit */
314 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
315 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
316
317 r = dm_tm_pre_commit(cmd->tm);
318 if (r < 0)
319 return r;
320
321 /*
322 * dm_sm_copy_root() can fail. So we need to do it before we start
323 * updating the superblock.
324 */
325 r = __save_sm_root(cmd);
326 if (r)
327 return r;
328
329 r = superblock_lock_zero(cmd, &sblock);
330 if (r)
331 return r;
332
333 disk_super = dm_block_data(sblock);
334 disk_super->flags = 0;
335 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
336 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
337 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
338 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
339 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
340 disk_super->policy_hint_size = 0;
341
342 __copy_sm_root(cmd, disk_super);
343
344 disk_super->mapping_root = cpu_to_le64(cmd->root);
345 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
346 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
347 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
348 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
349 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
350 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
351 disk_super->cache_blocks = cpu_to_le32(0);
352
353 disk_super->read_hits = cpu_to_le32(0);
354 disk_super->read_misses = cpu_to_le32(0);
355 disk_super->write_hits = cpu_to_le32(0);
356 disk_super->write_misses = cpu_to_le32(0);
357
358 return dm_tm_commit(cmd->tm, sblock);
359}
360
361static int __format_metadata(struct dm_cache_metadata *cmd)
362{
363 int r;
364
365 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
366 &cmd->tm, &cmd->metadata_sm);
367 if (r < 0) {
368 DMERR("tm_create_with_sm failed");
369 return r;
370 }
371
372 __setup_mapping_info(cmd);
373
374 r = dm_array_empty(&cmd->info, &cmd->root);
375 if (r < 0)
376 goto bad;
377
378 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
379
380 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
381 if (r < 0)
382 goto bad;
383
384 cmd->discard_block_size = 0;
385 cmd->discard_nr_blocks = 0;
386
387 r = __write_initial_superblock(cmd);
388 if (r)
389 goto bad;
390
391 cmd->clean_when_opened = true;
392 return 0;
393
394bad:
395 dm_tm_destroy(cmd->tm);
396 dm_sm_destroy(cmd->metadata_sm);
397
398 return r;
399}
400
401static int __check_incompat_features(struct cache_disk_superblock *disk_super,
402 struct dm_cache_metadata *cmd)
403{
404 uint32_t features;
405
406 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
407 if (features) {
408 DMERR("could not access metadata due to unsupported optional features (%lx).",
409 (unsigned long)features);
410 return -EINVAL;
411 }
412
413 /*
414 * Check for read-only metadata to skip the following RDWR checks.
415 */
416 if (get_disk_ro(cmd->bdev->bd_disk))
417 return 0;
418
419 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
420 if (features) {
421 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
422 (unsigned long)features);
423 return -EINVAL;
424 }
425
426 return 0;
427}
428
429static int __open_metadata(struct dm_cache_metadata *cmd)
430{
431 int r;
432 struct dm_block *sblock;
433 struct cache_disk_superblock *disk_super;
434 unsigned long sb_flags;
435
436 r = superblock_read_lock(cmd, &sblock);
437 if (r < 0) {
438 DMERR("couldn't read lock superblock");
439 return r;
440 }
441
442 disk_super = dm_block_data(sblock);
443
444 /* Verify the data block size hasn't changed */
445 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
446 DMERR("changing the data block size (from %u to %llu) is not supported",
447 le32_to_cpu(disk_super->data_block_size),
448 (unsigned long long)cmd->data_block_size);
449 r = -EINVAL;
450 goto bad;
451 }
452
453 r = __check_incompat_features(disk_super, cmd);
454 if (r < 0)
455 goto bad;
456
457 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
458 disk_super->metadata_space_map_root,
459 sizeof(disk_super->metadata_space_map_root),
460 &cmd->tm, &cmd->metadata_sm);
461 if (r < 0) {
462 DMERR("tm_open_with_sm failed");
463 goto bad;
464 }
465
466 __setup_mapping_info(cmd);
467 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
468 sb_flags = le32_to_cpu(disk_super->flags);
469 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
470 dm_bm_unlock(sblock);
471
472 return 0;
473
474bad:
475 dm_bm_unlock(sblock);
476 return r;
477}
478
479static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
480 bool format_device)
481{
482 int r;
483 bool unformatted = false;
484
485 r = __superblock_all_zeroes(cmd->bm, &unformatted);
486 if (r)
487 return r;
488
489 if (unformatted)
490 return format_device ? __format_metadata(cmd) : -EPERM;
491
492 return __open_metadata(cmd);
493}
494
495static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
496 bool may_format_device)
497{
498 int r;
499 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
500 CACHE_METADATA_CACHE_SIZE,
501 CACHE_MAX_CONCURRENT_LOCKS);
502 if (IS_ERR(cmd->bm)) {
503 DMERR("could not create block manager");
504 return PTR_ERR(cmd->bm);
505 }
506
507 r = __open_or_format_metadata(cmd, may_format_device);
508 if (r)
509 dm_block_manager_destroy(cmd->bm);
510
511 return r;
512}
513
514static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
515{
516 dm_sm_destroy(cmd->metadata_sm);
517 dm_tm_destroy(cmd->tm);
518 dm_block_manager_destroy(cmd->bm);
519}
520
521typedef unsigned long (*flags_mutator)(unsigned long);
522
523static void update_flags(struct cache_disk_superblock *disk_super,
524 flags_mutator mutator)
525{
526 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
527 disk_super->flags = cpu_to_le32(sb_flags);
528}
529
530static unsigned long set_clean_shutdown(unsigned long flags)
531{
532 set_bit(CLEAN_SHUTDOWN, &flags);
533 return flags;
534}
535
536static unsigned long clear_clean_shutdown(unsigned long flags)
537{
538 clear_bit(CLEAN_SHUTDOWN, &flags);
539 return flags;
540}
541
542static void read_superblock_fields(struct dm_cache_metadata *cmd,
543 struct cache_disk_superblock *disk_super)
544{
545 cmd->flags = le32_to_cpu(disk_super->flags);
546 cmd->root = le64_to_cpu(disk_super->mapping_root);
547 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
548 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
549 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
550 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
551 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
552 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
553 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
554 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
555 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
556 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
557 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
558
559 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
560 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
561 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
562 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
563
564 cmd->changed = false;
565}
566
567/*
568 * The mutator updates the superblock flags.
569 */
570static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
571 flags_mutator mutator)
572{
573 int r;
574 struct cache_disk_superblock *disk_super;
575 struct dm_block *sblock;
576
577 r = superblock_lock(cmd, &sblock);
578 if (r)
579 return r;
580
581 disk_super = dm_block_data(sblock);
582 update_flags(disk_super, mutator);
583 read_superblock_fields(cmd, disk_super);
584 dm_bm_unlock(sblock);
585
586 return dm_bm_flush(cmd->bm);
587}
588
589static int __begin_transaction(struct dm_cache_metadata *cmd)
590{
591 int r;
592 struct cache_disk_superblock *disk_super;
593 struct dm_block *sblock;
594
595 /*
596 * We re-read the superblock every time. Shouldn't need to do this
597 * really.
598 */
599 r = superblock_read_lock(cmd, &sblock);
600 if (r)
601 return r;
602
603 disk_super = dm_block_data(sblock);
604 read_superblock_fields(cmd, disk_super);
605 dm_bm_unlock(sblock);
606
607 return 0;
608}
609
610static int __commit_transaction(struct dm_cache_metadata *cmd,
611 flags_mutator mutator)
612{
613 int r;
614 struct cache_disk_superblock *disk_super;
615 struct dm_block *sblock;
616
617 /*
618 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
619 */
620 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
621
622 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
623 &cmd->discard_root);
624 if (r)
625 return r;
626
627 r = dm_tm_pre_commit(cmd->tm);
628 if (r < 0)
629 return r;
630
631 r = __save_sm_root(cmd);
632 if (r)
633 return r;
634
635 r = superblock_lock(cmd, &sblock);
636 if (r)
637 return r;
638
639 disk_super = dm_block_data(sblock);
640
641 disk_super->flags = cpu_to_le32(cmd->flags);
642 if (mutator)
643 update_flags(disk_super, mutator);
644
645 disk_super->mapping_root = cpu_to_le64(cmd->root);
646 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
647 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
648 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
649 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
650 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
651 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
652 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
653 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
654 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
655
656 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
657 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
658 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
659 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
660 __copy_sm_root(cmd, disk_super);
661
662 return dm_tm_commit(cmd->tm, sblock);
663}
664
665/*----------------------------------------------------------------*/
666
667/*
668 * The mappings are held in a dm-array that has 64-bit values stored in
669 * little-endian format. The index is the cblock, the high 48bits of the
670 * value are the oblock and the low 16 bit the flags.
671 */
672#define FLAGS_MASK ((1 << 16) - 1)
673
674static __le64 pack_value(dm_oblock_t block, unsigned flags)
675{
676 uint64_t value = from_oblock(block);
677 value <<= 16;
678 value = value | (flags & FLAGS_MASK);
679 return cpu_to_le64(value);
680}
681
682static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
683{
684 uint64_t value = le64_to_cpu(value_le);
685 uint64_t b = value >> 16;
686 *block = to_oblock(b);
687 *flags = value & FLAGS_MASK;
688}
689
690/*----------------------------------------------------------------*/
691
692static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
693 sector_t data_block_size,
694 bool may_format_device,
695 size_t policy_hint_size)
696{
697 int r;
698 struct dm_cache_metadata *cmd;
699
700 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
701 if (!cmd) {
702 DMERR("could not allocate metadata struct");
703 return ERR_PTR(-ENOMEM);
704 }
705
706 atomic_set(&cmd->ref_count, 1);
707 init_rwsem(&cmd->root_lock);
708 cmd->bdev = bdev;
709 cmd->data_block_size = data_block_size;
710 cmd->cache_blocks = 0;
711 cmd->policy_hint_size = policy_hint_size;
712 cmd->changed = true;
713 cmd->fail_io = false;
714
715 r = __create_persistent_data_objects(cmd, may_format_device);
716 if (r) {
717 kfree(cmd);
718 return ERR_PTR(r);
719 }
720
721 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
722 if (r < 0) {
723 dm_cache_metadata_close(cmd);
724 return ERR_PTR(r);
725 }
726
727 return cmd;
728}
729
730/*
731 * We keep a little list of ref counted metadata objects to prevent two
732 * different target instances creating separate bufio instances. This is
733 * an issue if a table is reloaded before the suspend.
734 */
735static DEFINE_MUTEX(table_lock);
736static LIST_HEAD(table);
737
738static struct dm_cache_metadata *lookup(struct block_device *bdev)
739{
740 struct dm_cache_metadata *cmd;
741
742 list_for_each_entry(cmd, &table, list)
743 if (cmd->bdev == bdev) {
744 atomic_inc(&cmd->ref_count);
745 return cmd;
746 }
747
748 return NULL;
749}
750
751static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
752 sector_t data_block_size,
753 bool may_format_device,
754 size_t policy_hint_size)
755{
756 struct dm_cache_metadata *cmd, *cmd2;
757
758 mutex_lock(&table_lock);
759 cmd = lookup(bdev);
760 mutex_unlock(&table_lock);
761
762 if (cmd)
763 return cmd;
764
765 cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
766 if (!IS_ERR(cmd)) {
767 mutex_lock(&table_lock);
768 cmd2 = lookup(bdev);
769 if (cmd2) {
770 mutex_unlock(&table_lock);
771 __destroy_persistent_data_objects(cmd);
772 kfree(cmd);
773 return cmd2;
774 }
775 list_add(&cmd->list, &table);
776 mutex_unlock(&table_lock);
777 }
778
779 return cmd;
780}
781
782static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
783{
784 if (cmd->data_block_size != data_block_size) {
785 DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",
786 (unsigned long long) data_block_size,
787 (unsigned long long) cmd->data_block_size);
788 return false;
789 }
790
791 return true;
792}
793
794struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
795 sector_t data_block_size,
796 bool may_format_device,
797 size_t policy_hint_size)
798{
799 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
800 may_format_device, policy_hint_size);
801
802 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
803 dm_cache_metadata_close(cmd);
804 return ERR_PTR(-EINVAL);
805 }
806
807 return cmd;
808}
809
810void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
811{
812 if (atomic_dec_and_test(&cmd->ref_count)) {
813 mutex_lock(&table_lock);
814 list_del(&cmd->list);
815 mutex_unlock(&table_lock);
816
817 if (!cmd->fail_io)
818 __destroy_persistent_data_objects(cmd);
819 kfree(cmd);
820 }
821}
822
823/*
824 * Checks that the given cache block is either unmapped or clean.
825 */
826static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
827 bool *result)
828{
829 int r;
830 __le64 value;
831 dm_oblock_t ob;
832 unsigned flags;
833
834 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
835 if (r) {
836 DMERR("block_unmapped_or_clean failed");
837 return r;
838 }
839
840 unpack_value(value, &ob, &flags);
841 *result = !((flags & M_VALID) && (flags & M_DIRTY));
842
843 return 0;
844}
845
846static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
847 dm_cblock_t begin, dm_cblock_t end,
848 bool *result)
849{
850 int r;
851 *result = true;
852
853 while (begin != end) {
854 r = block_unmapped_or_clean(cmd, begin, result);
855 if (r)
856 return r;
857
858 if (!*result) {
859 DMERR("cache block %llu is dirty",
860 (unsigned long long) from_cblock(begin));
861 return 0;
862 }
863
864 begin = to_cblock(from_cblock(begin) + 1);
865 }
866
867 return 0;
868}
869
870static bool cmd_write_lock(struct dm_cache_metadata *cmd)
871{
872 down_write(&cmd->root_lock);
873 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
874 up_write(&cmd->root_lock);
875 return false;
876 }
877 return true;
878}
879
880#define WRITE_LOCK(cmd) \
881 do { \
882 if (!cmd_write_lock((cmd))) \
883 return -EINVAL; \
884 } while(0)
885
886#define WRITE_LOCK_VOID(cmd) \
887 do { \
888 if (!cmd_write_lock((cmd))) \
889 return; \
890 } while(0)
891
892#define WRITE_UNLOCK(cmd) \
893 up_write(&(cmd)->root_lock)
894
895static bool cmd_read_lock(struct dm_cache_metadata *cmd)
896{
897 down_read(&cmd->root_lock);
898 if (cmd->fail_io) {
899 up_read(&cmd->root_lock);
900 return false;
901 }
902 return true;
903}
904
905#define READ_LOCK(cmd) \
906 do { \
907 if (!cmd_read_lock((cmd))) \
908 return -EINVAL; \
909 } while(0)
910
911#define READ_LOCK_VOID(cmd) \
912 do { \
913 if (!cmd_read_lock((cmd))) \
914 return; \
915 } while(0)
916
917#define READ_UNLOCK(cmd) \
918 up_read(&(cmd)->root_lock)
919
920int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
921{
922 int r;
923 bool clean;
924 __le64 null_mapping = pack_value(0, 0);
925
926 WRITE_LOCK(cmd);
927 __dm_bless_for_disk(&null_mapping);
928
929 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
930 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
931 if (r) {
932 __dm_unbless_for_disk(&null_mapping);
933 goto out;
934 }
935
936 if (!clean) {
937 DMERR("unable to shrink cache due to dirty blocks");
938 r = -EINVAL;
939 __dm_unbless_for_disk(&null_mapping);
940 goto out;
941 }
942 }
943
944 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
945 from_cblock(new_cache_size),
946 &null_mapping, &cmd->root);
947 if (!r)
948 cmd->cache_blocks = new_cache_size;
949 cmd->changed = true;
950
951out:
952 WRITE_UNLOCK(cmd);
953
954 return r;
955}
956
957int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
958 sector_t discard_block_size,
959 dm_dblock_t new_nr_entries)
960{
961 int r;
962
963 WRITE_LOCK(cmd);
964 r = dm_bitset_resize(&cmd->discard_info,
965 cmd->discard_root,
966 from_dblock(cmd->discard_nr_blocks),
967 from_dblock(new_nr_entries),
968 false, &cmd->discard_root);
969 if (!r) {
970 cmd->discard_block_size = discard_block_size;
971 cmd->discard_nr_blocks = new_nr_entries;
972 }
973
974 cmd->changed = true;
975 WRITE_UNLOCK(cmd);
976
977 return r;
978}
979
980static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
981{
982 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
983 from_dblock(b), &cmd->discard_root);
984}
985
986static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
987{
988 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
989 from_dblock(b), &cmd->discard_root);
990}
991
992static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
993 bool *is_discarded)
994{
995 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
996 from_dblock(b), &cmd->discard_root,
997 is_discarded);
998}
999
1000static int __discard(struct dm_cache_metadata *cmd,
1001 dm_dblock_t dblock, bool discard)
1002{
1003 int r;
1004
1005 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1006 if (r)
1007 return r;
1008
1009 cmd->changed = true;
1010 return 0;
1011}
1012
1013int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1014 dm_dblock_t dblock, bool discard)
1015{
1016 int r;
1017
1018 WRITE_LOCK(cmd);
1019 r = __discard(cmd, dblock, discard);
1020 WRITE_UNLOCK(cmd);
1021
1022 return r;
1023}
1024
1025static int __load_discards(struct dm_cache_metadata *cmd,
1026 load_discard_fn fn, void *context)
1027{
1028 int r = 0;
1029 dm_block_t b;
1030 bool discard;
1031
1032 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1033 dm_dblock_t dblock = to_dblock(b);
1034
1035 if (cmd->clean_when_opened) {
1036 r = __is_discarded(cmd, dblock, &discard);
1037 if (r)
1038 return r;
1039 } else
1040 discard = false;
1041
1042 r = fn(context, cmd->discard_block_size, dblock, discard);
1043 if (r)
1044 break;
1045 }
1046
1047 return r;
1048}
1049
1050int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1051 load_discard_fn fn, void *context)
1052{
1053 int r;
1054
1055 READ_LOCK(cmd);
1056 r = __load_discards(cmd, fn, context);
1057 READ_UNLOCK(cmd);
1058
1059 return r;
1060}
1061
1062int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1063{
1064 READ_LOCK(cmd);
1065 *result = cmd->cache_blocks;
1066 READ_UNLOCK(cmd);
1067
1068 return 0;
1069}
1070
1071static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1072{
1073 int r;
1074 __le64 value = pack_value(0, 0);
1075
1076 __dm_bless_for_disk(&value);
1077 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1078 &value, &cmd->root);
1079 if (r)
1080 return r;
1081
1082 cmd->changed = true;
1083 return 0;
1084}
1085
1086int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1087{
1088 int r;
1089
1090 WRITE_LOCK(cmd);
1091 r = __remove(cmd, cblock);
1092 WRITE_UNLOCK(cmd);
1093
1094 return r;
1095}
1096
1097static int __insert(struct dm_cache_metadata *cmd,
1098 dm_cblock_t cblock, dm_oblock_t oblock)
1099{
1100 int r;
1101 __le64 value = pack_value(oblock, M_VALID);
1102 __dm_bless_for_disk(&value);
1103
1104 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1105 &value, &cmd->root);
1106 if (r)
1107 return r;
1108
1109 cmd->changed = true;
1110 return 0;
1111}
1112
1113int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1114 dm_cblock_t cblock, dm_oblock_t oblock)
1115{
1116 int r;
1117
1118 WRITE_LOCK(cmd);
1119 r = __insert(cmd, cblock, oblock);
1120 WRITE_UNLOCK(cmd);
1121
1122 return r;
1123}
1124
1125struct thunk {
1126 load_mapping_fn fn;
1127 void *context;
1128
1129 struct dm_cache_metadata *cmd;
1130 bool respect_dirty_flags;
1131 bool hints_valid;
1132};
1133
1134static bool policy_unchanged(struct dm_cache_metadata *cmd,
1135 struct dm_cache_policy *policy)
1136{
1137 const char *policy_name = dm_cache_policy_get_name(policy);
1138 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1139 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1140
1141 /*
1142 * Ensure policy names match.
1143 */
1144 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1145 return false;
1146
1147 /*
1148 * Ensure policy major versions match.
1149 */
1150 if (cmd->policy_version[0] != policy_version[0])
1151 return false;
1152
1153 /*
1154 * Ensure policy hint sizes match.
1155 */
1156 if (cmd->policy_hint_size != policy_hint_size)
1157 return false;
1158
1159 return true;
1160}
1161
1162static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1163{
1164 return cmd->hint_root && cmd->policy_hint_size;
1165}
1166
1167static bool hints_array_available(struct dm_cache_metadata *cmd,
1168 struct dm_cache_policy *policy)
1169{
1170 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1171 hints_array_initialized(cmd);
1172}
1173
1174static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1175{
1176 int r = 0;
1177 bool dirty;
1178 __le64 value;
1179 __le32 hint_value = 0;
1180 dm_oblock_t oblock;
1181 unsigned flags;
1182 struct thunk *thunk = context;
1183 struct dm_cache_metadata *cmd = thunk->cmd;
1184
1185 memcpy(&value, leaf, sizeof(value));
1186 unpack_value(value, &oblock, &flags);
1187
1188 if (flags & M_VALID) {
1189 if (thunk->hints_valid) {
1190 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1191 cblock, &hint_value);
1192 if (r && r != -ENODATA)
1193 return r;
1194 }
1195
1196 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1197 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1198 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1199 }
1200
1201 return r;
1202}
1203
1204static int __load_mappings(struct dm_cache_metadata *cmd,
1205 struct dm_cache_policy *policy,
1206 load_mapping_fn fn, void *context)
1207{
1208 struct thunk thunk;
1209
1210 thunk.fn = fn;
1211 thunk.context = context;
1212
1213 thunk.cmd = cmd;
1214 thunk.respect_dirty_flags = cmd->clean_when_opened;
1215 thunk.hints_valid = hints_array_available(cmd, policy);
1216
1217 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1218}
1219
1220int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1221 struct dm_cache_policy *policy,
1222 load_mapping_fn fn, void *context)
1223{
1224 int r;
1225
1226 READ_LOCK(cmd);
1227 r = __load_mappings(cmd, policy, fn, context);
1228 READ_UNLOCK(cmd);
1229
1230 return r;
1231}
1232
1233static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1234{
1235 int r = 0;
1236 __le64 value;
1237 dm_oblock_t oblock;
1238 unsigned flags;
1239
1240 memcpy(&value, leaf, sizeof(value));
1241 unpack_value(value, &oblock, &flags);
1242
1243 return r;
1244}
1245
1246static int __dump_mappings(struct dm_cache_metadata *cmd)
1247{
1248 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1249}
1250
1251void dm_cache_dump(struct dm_cache_metadata *cmd)
1252{
1253 READ_LOCK_VOID(cmd);
1254 __dump_mappings(cmd);
1255 READ_UNLOCK(cmd);
1256}
1257
1258int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1259{
1260 int r;
1261
1262 READ_LOCK(cmd);
1263 r = cmd->changed;
1264 READ_UNLOCK(cmd);
1265
1266 return r;
1267}
1268
1269static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1270{
1271 int r;
1272 unsigned flags;
1273 dm_oblock_t oblock;
1274 __le64 value;
1275
1276 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1277 if (r)
1278 return r;
1279
1280 unpack_value(value, &oblock, &flags);
1281
1282 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1283 /* nothing to be done */
1284 return 0;
1285
1286 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1287 __dm_bless_for_disk(&value);
1288
1289 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1290 &value, &cmd->root);
1291 if (r)
1292 return r;
1293
1294 cmd->changed = true;
1295 return 0;
1296
1297}
1298
1299int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1300 dm_cblock_t cblock, bool dirty)
1301{
1302 int r;
1303
1304 WRITE_LOCK(cmd);
1305 r = __dirty(cmd, cblock, dirty);
1306 WRITE_UNLOCK(cmd);
1307
1308 return r;
1309}
1310
1311void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1312 struct dm_cache_statistics *stats)
1313{
1314 READ_LOCK_VOID(cmd);
1315 *stats = cmd->stats;
1316 READ_UNLOCK(cmd);
1317}
1318
1319void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1320 struct dm_cache_statistics *stats)
1321{
1322 WRITE_LOCK_VOID(cmd);
1323 cmd->stats = *stats;
1324 WRITE_UNLOCK(cmd);
1325}
1326
1327int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1328{
1329 int r;
1330 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1331 clear_clean_shutdown);
1332
1333 WRITE_LOCK(cmd);
1334 r = __commit_transaction(cmd, mutator);
1335 if (r)
1336 goto out;
1337
1338 r = __begin_transaction(cmd);
1339
1340out:
1341 WRITE_UNLOCK(cmd);
1342 return r;
1343}
1344
1345int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1346 dm_block_t *result)
1347{
1348 int r = -EINVAL;
1349
1350 READ_LOCK(cmd);
1351 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1352 READ_UNLOCK(cmd);
1353
1354 return r;
1355}
1356
1357int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1358 dm_block_t *result)
1359{
1360 int r = -EINVAL;
1361
1362 READ_LOCK(cmd);
1363 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1364 READ_UNLOCK(cmd);
1365
1366 return r;
1367}
1368
1369/*----------------------------------------------------------------*/
1370
1371static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1372{
1373 int r;
1374 __le32 value;
1375 size_t hint_size;
1376 const char *policy_name = dm_cache_policy_get_name(policy);
1377 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1378
1379 if (!policy_name[0] ||
1380 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1381 return -EINVAL;
1382
1383 if (!policy_unchanged(cmd, policy)) {
1384 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1385 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1386
1387 hint_size = dm_cache_policy_get_hint_size(policy);
1388 if (!hint_size)
1389 return 0; /* short-circuit hints initialization */
1390 cmd->policy_hint_size = hint_size;
1391
1392 if (cmd->hint_root) {
1393 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1394 if (r)
1395 return r;
1396 }
1397
1398 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1399 if (r)
1400 return r;
1401
1402 value = cpu_to_le32(0);
1403 __dm_bless_for_disk(&value);
1404 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1405 from_cblock(cmd->cache_blocks),
1406 &value, &cmd->hint_root);
1407 if (r)
1408 return r;
1409 }
1410
1411 return 0;
1412}
1413
1414static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1415{
1416 struct dm_cache_metadata *cmd = context;
1417 __le32 value = cpu_to_le32(hint);
1418 int r;
1419
1420 __dm_bless_for_disk(&value);
1421
1422 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1423 from_cblock(cblock), &value, &cmd->hint_root);
1424 cmd->changed = true;
1425
1426 return r;
1427}
1428
1429static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1430{
1431 int r;
1432
1433 r = begin_hints(cmd, policy);
1434 if (r) {
1435 DMERR("begin_hints failed");
1436 return r;
1437 }
1438
1439 return policy_walk_mappings(policy, save_hint, cmd);
1440}
1441
1442int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1443{
1444 int r;
1445
1446 WRITE_LOCK(cmd);
1447 r = write_hints(cmd, policy);
1448 WRITE_UNLOCK(cmd);
1449
1450 return r;
1451}
1452
1453int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1454{
1455 int r;
1456
1457 READ_LOCK(cmd);
1458 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1459 READ_UNLOCK(cmd);
1460
1461 return r;
1462}
1463
1464void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1465{
1466 WRITE_LOCK_VOID(cmd);
1467 dm_bm_set_read_only(cmd->bm);
1468 WRITE_UNLOCK(cmd);
1469}
1470
1471void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1472{
1473 WRITE_LOCK_VOID(cmd);
1474 dm_bm_set_read_write(cmd->bm);
1475 WRITE_UNLOCK(cmd);
1476}
1477
1478int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1479{
1480 int r;
1481 struct dm_block *sblock;
1482 struct cache_disk_superblock *disk_super;
1483
1484 WRITE_LOCK(cmd);
1485 set_bit(NEEDS_CHECK, &cmd->flags);
1486
1487 r = superblock_lock(cmd, &sblock);
1488 if (r) {
1489 DMERR("couldn't read superblock");
1490 goto out;
1491 }
1492
1493 disk_super = dm_block_data(sblock);
1494 disk_super->flags = cpu_to_le32(cmd->flags);
1495
1496 dm_bm_unlock(sblock);
1497
1498out:
1499 WRITE_UNLOCK(cmd);
1500 return r;
1501}
1502
1503int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1504{
1505 READ_LOCK(cmd);
1506 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1507 READ_UNLOCK(cmd);
1508
1509 return 0;
1510}
1511
1512int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1513{
1514 int r;
1515
1516 WRITE_LOCK(cmd);
1517 __destroy_persistent_data_objects(cmd);
1518 r = __create_persistent_data_objects(cmd, false);
1519 if (r)
1520 cmd->fail_io = true;
1521 WRITE_UNLOCK(cmd);
1522
1523 return r;
1524}