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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 * These structures are used when loading metadata. They're too
146 * big to put on the stack.
147 */
148 struct dm_array_cursor mapping_cursor;
149 struct dm_array_cursor hint_cursor;
150};
151
152/*-------------------------------------------------------------------
153 * superblock validator
154 *-----------------------------------------------------------------*/
155
156#define SUPERBLOCK_CSUM_XOR 9031977
157
158static void sb_prepare_for_write(struct dm_block_validator *v,
159 struct dm_block *b,
160 size_t sb_block_size)
161{
162 struct cache_disk_superblock *disk_super = dm_block_data(b);
163
164 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
165 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
166 sb_block_size - sizeof(__le32),
167 SUPERBLOCK_CSUM_XOR));
168}
169
170static int check_metadata_version(struct cache_disk_superblock *disk_super)
171{
172 uint32_t metadata_version = le32_to_cpu(disk_super->version);
173 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
174 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
175 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
176 return -EINVAL;
177 }
178
179 return 0;
180}
181
182static int sb_check(struct dm_block_validator *v,
183 struct dm_block *b,
184 size_t sb_block_size)
185{
186 struct cache_disk_superblock *disk_super = dm_block_data(b);
187 __le32 csum_le;
188
189 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
190 DMERR("sb_check failed: blocknr %llu: wanted %llu",
191 le64_to_cpu(disk_super->blocknr),
192 (unsigned long long)dm_block_location(b));
193 return -ENOTBLK;
194 }
195
196 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
197 DMERR("sb_check failed: magic %llu: wanted %llu",
198 le64_to_cpu(disk_super->magic),
199 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
200 return -EILSEQ;
201 }
202
203 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
204 sb_block_size - sizeof(__le32),
205 SUPERBLOCK_CSUM_XOR));
206 if (csum_le != disk_super->csum) {
207 DMERR("sb_check failed: csum %u: wanted %u",
208 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
209 return -EILSEQ;
210 }
211
212 return check_metadata_version(disk_super);
213}
214
215static struct dm_block_validator sb_validator = {
216 .name = "superblock",
217 .prepare_for_write = sb_prepare_for_write,
218 .check = sb_check
219};
220
221/*----------------------------------------------------------------*/
222
223static int superblock_read_lock(struct dm_cache_metadata *cmd,
224 struct dm_block **sblock)
225{
226 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
227 &sb_validator, sblock);
228}
229
230static int superblock_lock_zero(struct dm_cache_metadata *cmd,
231 struct dm_block **sblock)
232{
233 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
234 &sb_validator, sblock);
235}
236
237static int superblock_lock(struct dm_cache_metadata *cmd,
238 struct dm_block **sblock)
239{
240 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
241 &sb_validator, sblock);
242}
243
244/*----------------------------------------------------------------*/
245
246static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
247{
248 int r;
249 unsigned i;
250 struct dm_block *b;
251 __le64 *data_le, zero = cpu_to_le64(0);
252 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
253
254 /*
255 * We can't use a validator here - it may be all zeroes.
256 */
257 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
258 if (r)
259 return r;
260
261 data_le = dm_block_data(b);
262 *result = true;
263 for (i = 0; i < sb_block_size; i++) {
264 if (data_le[i] != zero) {
265 *result = false;
266 break;
267 }
268 }
269
270 dm_bm_unlock(b);
271
272 return 0;
273}
274
275static void __setup_mapping_info(struct dm_cache_metadata *cmd)
276{
277 struct dm_btree_value_type vt;
278
279 vt.context = NULL;
280 vt.size = sizeof(__le64);
281 vt.inc = NULL;
282 vt.dec = NULL;
283 vt.equal = NULL;
284 dm_array_info_init(&cmd->info, cmd->tm, &vt);
285
286 if (cmd->policy_hint_size) {
287 vt.size = sizeof(__le32);
288 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
289 }
290}
291
292static int __save_sm_root(struct dm_cache_metadata *cmd)
293{
294 int r;
295 size_t metadata_len;
296
297 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
298 if (r < 0)
299 return r;
300
301 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
302 metadata_len);
303}
304
305static void __copy_sm_root(struct dm_cache_metadata *cmd,
306 struct cache_disk_superblock *disk_super)
307{
308 memcpy(&disk_super->metadata_space_map_root,
309 &cmd->metadata_space_map_root,
310 sizeof(cmd->metadata_space_map_root));
311}
312
313static int __write_initial_superblock(struct dm_cache_metadata *cmd)
314{
315 int r;
316 struct dm_block *sblock;
317 struct cache_disk_superblock *disk_super;
318 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
319
320 /* FIXME: see if we can lose the max sectors limit */
321 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
322 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
323
324 r = dm_tm_pre_commit(cmd->tm);
325 if (r < 0)
326 return r;
327
328 /*
329 * dm_sm_copy_root() can fail. So we need to do it before we start
330 * updating the superblock.
331 */
332 r = __save_sm_root(cmd);
333 if (r)
334 return r;
335
336 r = superblock_lock_zero(cmd, &sblock);
337 if (r)
338 return r;
339
340 disk_super = dm_block_data(sblock);
341 disk_super->flags = 0;
342 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
343 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
344 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
345 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
346 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
347 disk_super->policy_hint_size = 0;
348
349 __copy_sm_root(cmd, disk_super);
350
351 disk_super->mapping_root = cpu_to_le64(cmd->root);
352 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
353 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
354 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
355 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
356 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
357 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
358 disk_super->cache_blocks = cpu_to_le32(0);
359
360 disk_super->read_hits = cpu_to_le32(0);
361 disk_super->read_misses = cpu_to_le32(0);
362 disk_super->write_hits = cpu_to_le32(0);
363 disk_super->write_misses = cpu_to_le32(0);
364
365 return dm_tm_commit(cmd->tm, sblock);
366}
367
368static int __format_metadata(struct dm_cache_metadata *cmd)
369{
370 int r;
371
372 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
373 &cmd->tm, &cmd->metadata_sm);
374 if (r < 0) {
375 DMERR("tm_create_with_sm failed");
376 return r;
377 }
378
379 __setup_mapping_info(cmd);
380
381 r = dm_array_empty(&cmd->info, &cmd->root);
382 if (r < 0)
383 goto bad;
384
385 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
386 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
387 if (r < 0)
388 goto bad;
389
390 cmd->discard_block_size = 0;
391 cmd->discard_nr_blocks = 0;
392
393 r = __write_initial_superblock(cmd);
394 if (r)
395 goto bad;
396
397 cmd->clean_when_opened = true;
398 return 0;
399
400bad:
401 dm_tm_destroy(cmd->tm);
402 dm_sm_destroy(cmd->metadata_sm);
403
404 return r;
405}
406
407static int __check_incompat_features(struct cache_disk_superblock *disk_super,
408 struct dm_cache_metadata *cmd)
409{
410 uint32_t features;
411
412 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
413 if (features) {
414 DMERR("could not access metadata due to unsupported optional features (%lx).",
415 (unsigned long)features);
416 return -EINVAL;
417 }
418
419 /*
420 * Check for read-only metadata to skip the following RDWR checks.
421 */
422 if (get_disk_ro(cmd->bdev->bd_disk))
423 return 0;
424
425 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
426 if (features) {
427 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
428 (unsigned long)features);
429 return -EINVAL;
430 }
431
432 return 0;
433}
434
435static int __open_metadata(struct dm_cache_metadata *cmd)
436{
437 int r;
438 struct dm_block *sblock;
439 struct cache_disk_superblock *disk_super;
440 unsigned long sb_flags;
441
442 r = superblock_read_lock(cmd, &sblock);
443 if (r < 0) {
444 DMERR("couldn't read lock superblock");
445 return r;
446 }
447
448 disk_super = dm_block_data(sblock);
449
450 /* Verify the data block size hasn't changed */
451 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
452 DMERR("changing the data block size (from %u to %llu) is not supported",
453 le32_to_cpu(disk_super->data_block_size),
454 (unsigned long long)cmd->data_block_size);
455 r = -EINVAL;
456 goto bad;
457 }
458
459 r = __check_incompat_features(disk_super, cmd);
460 if (r < 0)
461 goto bad;
462
463 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
464 disk_super->metadata_space_map_root,
465 sizeof(disk_super->metadata_space_map_root),
466 &cmd->tm, &cmd->metadata_sm);
467 if (r < 0) {
468 DMERR("tm_open_with_sm failed");
469 goto bad;
470 }
471
472 __setup_mapping_info(cmd);
473 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
474 sb_flags = le32_to_cpu(disk_super->flags);
475 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
476 dm_bm_unlock(sblock);
477
478 return 0;
479
480bad:
481 dm_bm_unlock(sblock);
482 return r;
483}
484
485static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
486 bool format_device)
487{
488 int r;
489 bool unformatted = false;
490
491 r = __superblock_all_zeroes(cmd->bm, &unformatted);
492 if (r)
493 return r;
494
495 if (unformatted)
496 return format_device ? __format_metadata(cmd) : -EPERM;
497
498 return __open_metadata(cmd);
499}
500
501static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
502 bool may_format_device)
503{
504 int r;
505 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
506 CACHE_METADATA_CACHE_SIZE,
507 CACHE_MAX_CONCURRENT_LOCKS);
508 if (IS_ERR(cmd->bm)) {
509 DMERR("could not create block manager");
510 return PTR_ERR(cmd->bm);
511 }
512
513 r = __open_or_format_metadata(cmd, may_format_device);
514 if (r)
515 dm_block_manager_destroy(cmd->bm);
516
517 return r;
518}
519
520static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
521{
522 dm_sm_destroy(cmd->metadata_sm);
523 dm_tm_destroy(cmd->tm);
524 dm_block_manager_destroy(cmd->bm);
525}
526
527typedef unsigned long (*flags_mutator)(unsigned long);
528
529static void update_flags(struct cache_disk_superblock *disk_super,
530 flags_mutator mutator)
531{
532 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
533 disk_super->flags = cpu_to_le32(sb_flags);
534}
535
536static unsigned long set_clean_shutdown(unsigned long flags)
537{
538 set_bit(CLEAN_SHUTDOWN, &flags);
539 return flags;
540}
541
542static unsigned long clear_clean_shutdown(unsigned long flags)
543{
544 clear_bit(CLEAN_SHUTDOWN, &flags);
545 return flags;
546}
547
548static void read_superblock_fields(struct dm_cache_metadata *cmd,
549 struct cache_disk_superblock *disk_super)
550{
551 cmd->flags = le32_to_cpu(disk_super->flags);
552 cmd->root = le64_to_cpu(disk_super->mapping_root);
553 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
554 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
555 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
556 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
557 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
558 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
559 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
560 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
561 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
562 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
563 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
564
565 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
566 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
567 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
568 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
569
570 cmd->changed = false;
571}
572
573/*
574 * The mutator updates the superblock flags.
575 */
576static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
577 flags_mutator mutator)
578{
579 int r;
580 struct cache_disk_superblock *disk_super;
581 struct dm_block *sblock;
582
583 r = superblock_lock(cmd, &sblock);
584 if (r)
585 return r;
586
587 disk_super = dm_block_data(sblock);
588 update_flags(disk_super, mutator);
589 read_superblock_fields(cmd, disk_super);
590 dm_bm_unlock(sblock);
591
592 return dm_bm_flush(cmd->bm);
593}
594
595static int __begin_transaction(struct dm_cache_metadata *cmd)
596{
597 int r;
598 struct cache_disk_superblock *disk_super;
599 struct dm_block *sblock;
600
601 /*
602 * We re-read the superblock every time. Shouldn't need to do this
603 * really.
604 */
605 r = superblock_read_lock(cmd, &sblock);
606 if (r)
607 return r;
608
609 disk_super = dm_block_data(sblock);
610 read_superblock_fields(cmd, disk_super);
611 dm_bm_unlock(sblock);
612
613 return 0;
614}
615
616static int __commit_transaction(struct dm_cache_metadata *cmd,
617 flags_mutator mutator)
618{
619 int r;
620 struct cache_disk_superblock *disk_super;
621 struct dm_block *sblock;
622
623 /*
624 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
625 */
626 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
627
628 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
629 &cmd->discard_root);
630 if (r)
631 return r;
632
633 r = dm_tm_pre_commit(cmd->tm);
634 if (r < 0)
635 return r;
636
637 r = __save_sm_root(cmd);
638 if (r)
639 return r;
640
641 r = superblock_lock(cmd, &sblock);
642 if (r)
643 return r;
644
645 disk_super = dm_block_data(sblock);
646
647 disk_super->flags = cpu_to_le32(cmd->flags);
648 if (mutator)
649 update_flags(disk_super, mutator);
650
651 disk_super->mapping_root = cpu_to_le64(cmd->root);
652 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
653 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
654 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
655 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
656 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
657 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
658 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
659 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
660 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
661
662 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
663 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
664 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
665 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
666 __copy_sm_root(cmd, disk_super);
667
668 return dm_tm_commit(cmd->tm, sblock);
669}
670
671/*----------------------------------------------------------------*/
672
673/*
674 * The mappings are held in a dm-array that has 64-bit values stored in
675 * little-endian format. The index is the cblock, the high 48bits of the
676 * value are the oblock and the low 16 bit the flags.
677 */
678#define FLAGS_MASK ((1 << 16) - 1)
679
680static __le64 pack_value(dm_oblock_t block, unsigned flags)
681{
682 uint64_t value = from_oblock(block);
683 value <<= 16;
684 value = value | (flags & FLAGS_MASK);
685 return cpu_to_le64(value);
686}
687
688static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
689{
690 uint64_t value = le64_to_cpu(value_le);
691 uint64_t b = value >> 16;
692 *block = to_oblock(b);
693 *flags = value & FLAGS_MASK;
694}
695
696/*----------------------------------------------------------------*/
697
698static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
699 sector_t data_block_size,
700 bool may_format_device,
701 size_t policy_hint_size)
702{
703 int r;
704 struct dm_cache_metadata *cmd;
705
706 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
707 if (!cmd) {
708 DMERR("could not allocate metadata struct");
709 return ERR_PTR(-ENOMEM);
710 }
711
712 atomic_set(&cmd->ref_count, 1);
713 init_rwsem(&cmd->root_lock);
714 cmd->bdev = bdev;
715 cmd->data_block_size = data_block_size;
716 cmd->cache_blocks = 0;
717 cmd->policy_hint_size = policy_hint_size;
718 cmd->changed = true;
719 cmd->fail_io = false;
720
721 r = __create_persistent_data_objects(cmd, may_format_device);
722 if (r) {
723 kfree(cmd);
724 return ERR_PTR(r);
725 }
726
727 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
728 if (r < 0) {
729 dm_cache_metadata_close(cmd);
730 return ERR_PTR(r);
731 }
732
733 return cmd;
734}
735
736/*
737 * We keep a little list of ref counted metadata objects to prevent two
738 * different target instances creating separate bufio instances. This is
739 * an issue if a table is reloaded before the suspend.
740 */
741static DEFINE_MUTEX(table_lock);
742static LIST_HEAD(table);
743
744static struct dm_cache_metadata *lookup(struct block_device *bdev)
745{
746 struct dm_cache_metadata *cmd;
747
748 list_for_each_entry(cmd, &table, list)
749 if (cmd->bdev == bdev) {
750 atomic_inc(&cmd->ref_count);
751 return cmd;
752 }
753
754 return NULL;
755}
756
757static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
758 sector_t data_block_size,
759 bool may_format_device,
760 size_t policy_hint_size)
761{
762 struct dm_cache_metadata *cmd, *cmd2;
763
764 mutex_lock(&table_lock);
765 cmd = lookup(bdev);
766 mutex_unlock(&table_lock);
767
768 if (cmd)
769 return cmd;
770
771 cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
772 if (!IS_ERR(cmd)) {
773 mutex_lock(&table_lock);
774 cmd2 = lookup(bdev);
775 if (cmd2) {
776 mutex_unlock(&table_lock);
777 __destroy_persistent_data_objects(cmd);
778 kfree(cmd);
779 return cmd2;
780 }
781 list_add(&cmd->list, &table);
782 mutex_unlock(&table_lock);
783 }
784
785 return cmd;
786}
787
788static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
789{
790 if (cmd->data_block_size != data_block_size) {
791 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
792 (unsigned long long) data_block_size,
793 (unsigned long long) cmd->data_block_size);
794 return false;
795 }
796
797 return true;
798}
799
800struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
801 sector_t data_block_size,
802 bool may_format_device,
803 size_t policy_hint_size)
804{
805 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
806 may_format_device, policy_hint_size);
807
808 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
809 dm_cache_metadata_close(cmd);
810 return ERR_PTR(-EINVAL);
811 }
812
813 return cmd;
814}
815
816void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
817{
818 if (atomic_dec_and_test(&cmd->ref_count)) {
819 mutex_lock(&table_lock);
820 list_del(&cmd->list);
821 mutex_unlock(&table_lock);
822
823 if (!cmd->fail_io)
824 __destroy_persistent_data_objects(cmd);
825 kfree(cmd);
826 }
827}
828
829/*
830 * Checks that the given cache block is either unmapped or clean.
831 */
832static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
833 bool *result)
834{
835 int r;
836 __le64 value;
837 dm_oblock_t ob;
838 unsigned flags;
839
840 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
841 if (r) {
842 DMERR("block_unmapped_or_clean failed");
843 return r;
844 }
845
846 unpack_value(value, &ob, &flags);
847 *result = !((flags & M_VALID) && (flags & M_DIRTY));
848
849 return 0;
850}
851
852static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
853 dm_cblock_t begin, dm_cblock_t end,
854 bool *result)
855{
856 int r;
857 *result = true;
858
859 while (begin != end) {
860 r = block_unmapped_or_clean(cmd, begin, result);
861 if (r)
862 return r;
863
864 if (!*result) {
865 DMERR("cache block %llu is dirty",
866 (unsigned long long) from_cblock(begin));
867 return 0;
868 }
869
870 begin = to_cblock(from_cblock(begin) + 1);
871 }
872
873 return 0;
874}
875
876static bool cmd_write_lock(struct dm_cache_metadata *cmd)
877{
878 down_write(&cmd->root_lock);
879 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
880 up_write(&cmd->root_lock);
881 return false;
882 }
883 return true;
884}
885
886#define WRITE_LOCK(cmd) \
887 do { \
888 if (!cmd_write_lock((cmd))) \
889 return -EINVAL; \
890 } while(0)
891
892#define WRITE_LOCK_VOID(cmd) \
893 do { \
894 if (!cmd_write_lock((cmd))) \
895 return; \
896 } while(0)
897
898#define WRITE_UNLOCK(cmd) \
899 up_write(&(cmd)->root_lock)
900
901static bool cmd_read_lock(struct dm_cache_metadata *cmd)
902{
903 down_read(&cmd->root_lock);
904 if (cmd->fail_io) {
905 up_read(&cmd->root_lock);
906 return false;
907 }
908 return true;
909}
910
911#define READ_LOCK(cmd) \
912 do { \
913 if (!cmd_read_lock((cmd))) \
914 return -EINVAL; \
915 } while(0)
916
917#define READ_LOCK_VOID(cmd) \
918 do { \
919 if (!cmd_read_lock((cmd))) \
920 return; \
921 } while(0)
922
923#define READ_UNLOCK(cmd) \
924 up_read(&(cmd)->root_lock)
925
926int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
927{
928 int r;
929 bool clean;
930 __le64 null_mapping = pack_value(0, 0);
931
932 WRITE_LOCK(cmd);
933 __dm_bless_for_disk(&null_mapping);
934
935 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
936 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
937 if (r) {
938 __dm_unbless_for_disk(&null_mapping);
939 goto out;
940 }
941
942 if (!clean) {
943 DMERR("unable to shrink cache due to dirty blocks");
944 r = -EINVAL;
945 __dm_unbless_for_disk(&null_mapping);
946 goto out;
947 }
948 }
949
950 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
951 from_cblock(new_cache_size),
952 &null_mapping, &cmd->root);
953 if (!r)
954 cmd->cache_blocks = new_cache_size;
955 cmd->changed = true;
956
957out:
958 WRITE_UNLOCK(cmd);
959
960 return r;
961}
962
963int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
964 sector_t discard_block_size,
965 dm_dblock_t new_nr_entries)
966{
967 int r;
968
969 WRITE_LOCK(cmd);
970 r = dm_bitset_resize(&cmd->discard_info,
971 cmd->discard_root,
972 from_dblock(cmd->discard_nr_blocks),
973 from_dblock(new_nr_entries),
974 false, &cmd->discard_root);
975 if (!r) {
976 cmd->discard_block_size = discard_block_size;
977 cmd->discard_nr_blocks = new_nr_entries;
978 }
979
980 cmd->changed = true;
981 WRITE_UNLOCK(cmd);
982
983 return r;
984}
985
986static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
987{
988 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
989 from_dblock(b), &cmd->discard_root);
990}
991
992static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
993{
994 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
995 from_dblock(b), &cmd->discard_root);
996}
997
998static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
999 bool *is_discarded)
1000{
1001 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
1002 from_dblock(b), &cmd->discard_root,
1003 is_discarded);
1004}
1005
1006static int __discard(struct dm_cache_metadata *cmd,
1007 dm_dblock_t dblock, bool discard)
1008{
1009 int r;
1010
1011 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1012 if (r)
1013 return r;
1014
1015 cmd->changed = true;
1016 return 0;
1017}
1018
1019int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1020 dm_dblock_t dblock, bool discard)
1021{
1022 int r;
1023
1024 WRITE_LOCK(cmd);
1025 r = __discard(cmd, dblock, discard);
1026 WRITE_UNLOCK(cmd);
1027
1028 return r;
1029}
1030
1031static int __load_discards(struct dm_cache_metadata *cmd,
1032 load_discard_fn fn, void *context)
1033{
1034 int r = 0;
1035 dm_block_t b;
1036 bool discard;
1037
1038 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1039 dm_dblock_t dblock = to_dblock(b);
1040
1041 if (cmd->clean_when_opened) {
1042 r = __is_discarded(cmd, dblock, &discard);
1043 if (r)
1044 return r;
1045 } else
1046 discard = false;
1047
1048 r = fn(context, cmd->discard_block_size, dblock, discard);
1049 if (r)
1050 break;
1051 }
1052
1053 return r;
1054}
1055
1056int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1057 load_discard_fn fn, void *context)
1058{
1059 int r;
1060
1061 READ_LOCK(cmd);
1062 r = __load_discards(cmd, fn, context);
1063 READ_UNLOCK(cmd);
1064
1065 return r;
1066}
1067
1068int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1069{
1070 READ_LOCK(cmd);
1071 *result = cmd->cache_blocks;
1072 READ_UNLOCK(cmd);
1073
1074 return 0;
1075}
1076
1077static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1078{
1079 int r;
1080 __le64 value = pack_value(0, 0);
1081
1082 __dm_bless_for_disk(&value);
1083 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1084 &value, &cmd->root);
1085 if (r)
1086 return r;
1087
1088 cmd->changed = true;
1089 return 0;
1090}
1091
1092int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1093{
1094 int r;
1095
1096 WRITE_LOCK(cmd);
1097 r = __remove(cmd, cblock);
1098 WRITE_UNLOCK(cmd);
1099
1100 return r;
1101}
1102
1103static int __insert(struct dm_cache_metadata *cmd,
1104 dm_cblock_t cblock, dm_oblock_t oblock)
1105{
1106 int r;
1107 __le64 value = pack_value(oblock, M_VALID);
1108 __dm_bless_for_disk(&value);
1109
1110 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1111 &value, &cmd->root);
1112 if (r)
1113 return r;
1114
1115 cmd->changed = true;
1116 return 0;
1117}
1118
1119int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1120 dm_cblock_t cblock, dm_oblock_t oblock)
1121{
1122 int r;
1123
1124 WRITE_LOCK(cmd);
1125 r = __insert(cmd, cblock, oblock);
1126 WRITE_UNLOCK(cmd);
1127
1128 return r;
1129}
1130
1131struct thunk {
1132 load_mapping_fn fn;
1133 void *context;
1134
1135 struct dm_cache_metadata *cmd;
1136 bool respect_dirty_flags;
1137 bool hints_valid;
1138};
1139
1140static bool policy_unchanged(struct dm_cache_metadata *cmd,
1141 struct dm_cache_policy *policy)
1142{
1143 const char *policy_name = dm_cache_policy_get_name(policy);
1144 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1145 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1146
1147 /*
1148 * Ensure policy names match.
1149 */
1150 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1151 return false;
1152
1153 /*
1154 * Ensure policy major versions match.
1155 */
1156 if (cmd->policy_version[0] != policy_version[0])
1157 return false;
1158
1159 /*
1160 * Ensure policy hint sizes match.
1161 */
1162 if (cmd->policy_hint_size != policy_hint_size)
1163 return false;
1164
1165 return true;
1166}
1167
1168static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1169{
1170 return cmd->hint_root && cmd->policy_hint_size;
1171}
1172
1173static bool hints_array_available(struct dm_cache_metadata *cmd,
1174 struct dm_cache_policy *policy)
1175{
1176 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1177 hints_array_initialized(cmd);
1178}
1179
1180static int __load_mapping(struct dm_cache_metadata *cmd,
1181 uint64_t cb, bool hints_valid,
1182 struct dm_array_cursor *mapping_cursor,
1183 struct dm_array_cursor *hint_cursor,
1184 load_mapping_fn fn, void *context)
1185{
1186 int r = 0;
1187
1188 __le64 mapping;
1189 __le32 hint = 0;
1190
1191 __le64 *mapping_value_le;
1192 __le32 *hint_value_le;
1193
1194 dm_oblock_t oblock;
1195 unsigned flags;
1196
1197 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1198 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1199 unpack_value(mapping, &oblock, &flags);
1200
1201 if (flags & M_VALID) {
1202 if (hints_valid) {
1203 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1204 memcpy(&hint, hint_value_le, sizeof(hint));
1205 }
1206
1207 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1208 le32_to_cpu(hint), hints_valid);
1209 if (r)
1210 DMERR("policy couldn't load cblock");
1211 }
1212
1213 return r;
1214}
1215
1216static int __load_mappings(struct dm_cache_metadata *cmd,
1217 struct dm_cache_policy *policy,
1218 load_mapping_fn fn, void *context)
1219{
1220 int r;
1221 uint64_t cb;
1222
1223 bool hints_valid = hints_array_available(cmd, policy);
1224
1225 if (from_cblock(cmd->cache_blocks) == 0)
1226 /* Nothing to do */
1227 return 0;
1228
1229 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1230 if (r)
1231 return r;
1232
1233 if (hints_valid) {
1234 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1235 if (r) {
1236 dm_array_cursor_end(&cmd->mapping_cursor);
1237 return r;
1238 }
1239 }
1240
1241 for (cb = 0; ; cb++) {
1242 r = __load_mapping(cmd, cb, hints_valid,
1243 &cmd->mapping_cursor, &cmd->hint_cursor,
1244 fn, context);
1245 if (r)
1246 goto out;
1247
1248 /*
1249 * We need to break out before we move the cursors.
1250 */
1251 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1252 break;
1253
1254 r = dm_array_cursor_next(&cmd->mapping_cursor);
1255 if (r) {
1256 DMERR("dm_array_cursor_next for mapping failed");
1257 goto out;
1258 }
1259
1260 if (hints_valid) {
1261 r = dm_array_cursor_next(&cmd->hint_cursor);
1262 if (r) {
1263 DMERR("dm_array_cursor_next for hint failed");
1264 goto out;
1265 }
1266 }
1267 }
1268out:
1269 dm_array_cursor_end(&cmd->mapping_cursor);
1270 if (hints_valid)
1271 dm_array_cursor_end(&cmd->hint_cursor);
1272
1273 return r;
1274}
1275
1276int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1277 struct dm_cache_policy *policy,
1278 load_mapping_fn fn, void *context)
1279{
1280 int r;
1281
1282 READ_LOCK(cmd);
1283 r = __load_mappings(cmd, policy, fn, context);
1284 READ_UNLOCK(cmd);
1285
1286 return r;
1287}
1288
1289static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1290{
1291 int r = 0;
1292 __le64 value;
1293 dm_oblock_t oblock;
1294 unsigned flags;
1295
1296 memcpy(&value, leaf, sizeof(value));
1297 unpack_value(value, &oblock, &flags);
1298
1299 return r;
1300}
1301
1302static int __dump_mappings(struct dm_cache_metadata *cmd)
1303{
1304 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1305}
1306
1307void dm_cache_dump(struct dm_cache_metadata *cmd)
1308{
1309 READ_LOCK_VOID(cmd);
1310 __dump_mappings(cmd);
1311 READ_UNLOCK(cmd);
1312}
1313
1314int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1315{
1316 int r;
1317
1318 READ_LOCK(cmd);
1319 r = cmd->changed;
1320 READ_UNLOCK(cmd);
1321
1322 return r;
1323}
1324
1325static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1326{
1327 int r;
1328 unsigned flags;
1329 dm_oblock_t oblock;
1330 __le64 value;
1331
1332 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1333 if (r)
1334 return r;
1335
1336 unpack_value(value, &oblock, &flags);
1337
1338 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1339 /* nothing to be done */
1340 return 0;
1341
1342 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1343 __dm_bless_for_disk(&value);
1344
1345 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1346 &value, &cmd->root);
1347 if (r)
1348 return r;
1349
1350 cmd->changed = true;
1351 return 0;
1352
1353}
1354
1355int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1356 dm_cblock_t cblock, bool dirty)
1357{
1358 int r;
1359
1360 WRITE_LOCK(cmd);
1361 r = __dirty(cmd, cblock, dirty);
1362 WRITE_UNLOCK(cmd);
1363
1364 return r;
1365}
1366
1367void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1368 struct dm_cache_statistics *stats)
1369{
1370 READ_LOCK_VOID(cmd);
1371 *stats = cmd->stats;
1372 READ_UNLOCK(cmd);
1373}
1374
1375void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1376 struct dm_cache_statistics *stats)
1377{
1378 WRITE_LOCK_VOID(cmd);
1379 cmd->stats = *stats;
1380 WRITE_UNLOCK(cmd);
1381}
1382
1383int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1384{
1385 int r;
1386 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1387 clear_clean_shutdown);
1388
1389 WRITE_LOCK(cmd);
1390 r = __commit_transaction(cmd, mutator);
1391 if (r)
1392 goto out;
1393
1394 r = __begin_transaction(cmd);
1395
1396out:
1397 WRITE_UNLOCK(cmd);
1398 return r;
1399}
1400
1401int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1402 dm_block_t *result)
1403{
1404 int r = -EINVAL;
1405
1406 READ_LOCK(cmd);
1407 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1408 READ_UNLOCK(cmd);
1409
1410 return r;
1411}
1412
1413int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1414 dm_block_t *result)
1415{
1416 int r = -EINVAL;
1417
1418 READ_LOCK(cmd);
1419 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1420 READ_UNLOCK(cmd);
1421
1422 return r;
1423}
1424
1425/*----------------------------------------------------------------*/
1426
1427static int get_hint(uint32_t index, void *value_le, void *context)
1428{
1429 uint32_t value;
1430 struct dm_cache_policy *policy = context;
1431
1432 value = policy_get_hint(policy, to_cblock(index));
1433 *((__le32 *) value_le) = cpu_to_le32(value);
1434
1435 return 0;
1436}
1437
1438/*
1439 * It's quicker to always delete the hint array, and recreate with
1440 * dm_array_new().
1441 */
1442static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1443{
1444 int r;
1445 size_t hint_size;
1446 const char *policy_name = dm_cache_policy_get_name(policy);
1447 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1448
1449 if (!policy_name[0] ||
1450 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1451 return -EINVAL;
1452
1453 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1454 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1455
1456 hint_size = dm_cache_policy_get_hint_size(policy);
1457 if (!hint_size)
1458 return 0; /* short-circuit hints initialization */
1459 cmd->policy_hint_size = hint_size;
1460
1461 if (cmd->hint_root) {
1462 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1463 if (r)
1464 return r;
1465 }
1466
1467 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1468 from_cblock(cmd->cache_blocks),
1469 get_hint, policy);
1470}
1471
1472int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1473{
1474 int r;
1475
1476 WRITE_LOCK(cmd);
1477 r = write_hints(cmd, policy);
1478 WRITE_UNLOCK(cmd);
1479
1480 return r;
1481}
1482
1483int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1484{
1485 int r;
1486
1487 READ_LOCK(cmd);
1488 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1489 READ_UNLOCK(cmd);
1490
1491 return r;
1492}
1493
1494void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1495{
1496 WRITE_LOCK_VOID(cmd);
1497 dm_bm_set_read_only(cmd->bm);
1498 WRITE_UNLOCK(cmd);
1499}
1500
1501void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1502{
1503 WRITE_LOCK_VOID(cmd);
1504 dm_bm_set_read_write(cmd->bm);
1505 WRITE_UNLOCK(cmd);
1506}
1507
1508int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1509{
1510 int r;
1511 struct dm_block *sblock;
1512 struct cache_disk_superblock *disk_super;
1513
1514 WRITE_LOCK(cmd);
1515 set_bit(NEEDS_CHECK, &cmd->flags);
1516
1517 r = superblock_lock(cmd, &sblock);
1518 if (r) {
1519 DMERR("couldn't read superblock");
1520 goto out;
1521 }
1522
1523 disk_super = dm_block_data(sblock);
1524 disk_super->flags = cpu_to_le32(cmd->flags);
1525
1526 dm_bm_unlock(sblock);
1527
1528out:
1529 WRITE_UNLOCK(cmd);
1530 return r;
1531}
1532
1533int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1534{
1535 READ_LOCK(cmd);
1536 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1537 READ_UNLOCK(cmd);
1538
1539 return 0;
1540}
1541
1542int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1543{
1544 int r;
1545
1546 WRITE_LOCK(cmd);
1547 __destroy_persistent_data_objects(cmd);
1548 r = __create_persistent_data_objects(cmd, false);
1549 if (r)
1550 cmd->fail_io = true;
1551 WRITE_UNLOCK(cmd);
1552
1553 return r;
1554}