arm64: perf: don't expose CHAIN event in sysfs
[linux-2.6-block.git] / drivers / md / dm-cache-metadata.c
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
39 enum 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  */
49 enum 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
62 struct 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
98 struct 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
151 static 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
163 static 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
175 static 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
208 static 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
216 static 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
223 static 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
230 static 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
239 static 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
268 static 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
285 static 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
298 static 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
306 static 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
361 static 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
394 bad:
395         dm_tm_destroy(cmd->tm);
396         dm_sm_destroy(cmd->metadata_sm);
397
398         return r;
399 }
400
401 static 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
429 static 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
474 bad:
475         dm_bm_unlock(sblock);
476         return r;
477 }
478
479 static 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
495 static 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
514 static 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
521 typedef unsigned long (*flags_mutator)(unsigned long);
522
523 static 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
530 static unsigned long set_clean_shutdown(unsigned long flags)
531 {
532         set_bit(CLEAN_SHUTDOWN, &flags);
533         return flags;
534 }
535
536 static unsigned long clear_clean_shutdown(unsigned long flags)
537 {
538         clear_bit(CLEAN_SHUTDOWN, &flags);
539         return flags;
540 }
541
542 static 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  */
570 static 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
589 static 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
610 static 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
674 static __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
682 static 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
692 static 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  */
735 static DEFINE_MUTEX(table_lock);
736 static LIST_HEAD(table);
737
738 static 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
751 static 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
782 static 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
794 struct 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
810 void 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  */
826 static 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
846 static 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
870 #define WRITE_LOCK(cmd) \
871         down_write(&cmd->root_lock); \
872         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
873                 up_write(&cmd->root_lock); \
874                 return -EINVAL; \
875         }
876
877 #define WRITE_LOCK_VOID(cmd) \
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; \
882         }
883
884 #define WRITE_UNLOCK(cmd) \
885         up_write(&cmd->root_lock)
886
887 #define READ_LOCK(cmd) \
888         down_read(&cmd->root_lock); \
889         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
890                 up_read(&cmd->root_lock); \
891                 return -EINVAL; \
892         }
893
894 #define READ_LOCK_VOID(cmd)     \
895         down_read(&cmd->root_lock); \
896         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \
897                 up_read(&cmd->root_lock); \
898                 return; \
899         }
900
901 #define READ_UNLOCK(cmd) \
902         up_read(&cmd->root_lock)
903
904 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
905 {
906         int r;
907         bool clean;
908         __le64 null_mapping = pack_value(0, 0);
909
910         WRITE_LOCK(cmd);
911         __dm_bless_for_disk(&null_mapping);
912
913         if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
914                 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
915                 if (r) {
916                         __dm_unbless_for_disk(&null_mapping);
917                         goto out;
918                 }
919
920                 if (!clean) {
921                         DMERR("unable to shrink cache due to dirty blocks");
922                         r = -EINVAL;
923                         __dm_unbless_for_disk(&null_mapping);
924                         goto out;
925                 }
926         }
927
928         r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
929                             from_cblock(new_cache_size),
930                             &null_mapping, &cmd->root);
931         if (!r)
932                 cmd->cache_blocks = new_cache_size;
933         cmd->changed = true;
934
935 out:
936         WRITE_UNLOCK(cmd);
937
938         return r;
939 }
940
941 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
942                                    sector_t discard_block_size,
943                                    dm_dblock_t new_nr_entries)
944 {
945         int r;
946
947         WRITE_LOCK(cmd);
948         r = dm_bitset_resize(&cmd->discard_info,
949                              cmd->discard_root,
950                              from_dblock(cmd->discard_nr_blocks),
951                              from_dblock(new_nr_entries),
952                              false, &cmd->discard_root);
953         if (!r) {
954                 cmd->discard_block_size = discard_block_size;
955                 cmd->discard_nr_blocks = new_nr_entries;
956         }
957
958         cmd->changed = true;
959         WRITE_UNLOCK(cmd);
960
961         return r;
962 }
963
964 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
965 {
966         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
967                                  from_dblock(b), &cmd->discard_root);
968 }
969
970 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
971 {
972         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
973                                    from_dblock(b), &cmd->discard_root);
974 }
975
976 static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
977                           bool *is_discarded)
978 {
979         return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
980                                   from_dblock(b), &cmd->discard_root,
981                                   is_discarded);
982 }
983
984 static int __discard(struct dm_cache_metadata *cmd,
985                      dm_dblock_t dblock, bool discard)
986 {
987         int r;
988
989         r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
990         if (r)
991                 return r;
992
993         cmd->changed = true;
994         return 0;
995 }
996
997 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
998                          dm_dblock_t dblock, bool discard)
999 {
1000         int r;
1001
1002         WRITE_LOCK(cmd);
1003         r = __discard(cmd, dblock, discard);
1004         WRITE_UNLOCK(cmd);
1005
1006         return r;
1007 }
1008
1009 static int __load_discards(struct dm_cache_metadata *cmd,
1010                            load_discard_fn fn, void *context)
1011 {
1012         int r = 0;
1013         dm_block_t b;
1014         bool discard;
1015
1016         for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1017                 dm_dblock_t dblock = to_dblock(b);
1018
1019                 if (cmd->clean_when_opened) {
1020                         r = __is_discarded(cmd, dblock, &discard);
1021                         if (r)
1022                                 return r;
1023                 } else
1024                         discard = false;
1025
1026                 r = fn(context, cmd->discard_block_size, dblock, discard);
1027                 if (r)
1028                         break;
1029         }
1030
1031         return r;
1032 }
1033
1034 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1035                            load_discard_fn fn, void *context)
1036 {
1037         int r;
1038
1039         READ_LOCK(cmd);
1040         r = __load_discards(cmd, fn, context);
1041         READ_UNLOCK(cmd);
1042
1043         return r;
1044 }
1045
1046 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1047 {
1048         READ_LOCK(cmd);
1049         *result = cmd->cache_blocks;
1050         READ_UNLOCK(cmd);
1051
1052         return 0;
1053 }
1054
1055 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1056 {
1057         int r;
1058         __le64 value = pack_value(0, 0);
1059
1060         __dm_bless_for_disk(&value);
1061         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1062                                &value, &cmd->root);
1063         if (r)
1064                 return r;
1065
1066         cmd->changed = true;
1067         return 0;
1068 }
1069
1070 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1071 {
1072         int r;
1073
1074         WRITE_LOCK(cmd);
1075         r = __remove(cmd, cblock);
1076         WRITE_UNLOCK(cmd);
1077
1078         return r;
1079 }
1080
1081 static int __insert(struct dm_cache_metadata *cmd,
1082                     dm_cblock_t cblock, dm_oblock_t oblock)
1083 {
1084         int r;
1085         __le64 value = pack_value(oblock, M_VALID);
1086         __dm_bless_for_disk(&value);
1087
1088         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1089                                &value, &cmd->root);
1090         if (r)
1091                 return r;
1092
1093         cmd->changed = true;
1094         return 0;
1095 }
1096
1097 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1098                             dm_cblock_t cblock, dm_oblock_t oblock)
1099 {
1100         int r;
1101
1102         WRITE_LOCK(cmd);
1103         r = __insert(cmd, cblock, oblock);
1104         WRITE_UNLOCK(cmd);
1105
1106         return r;
1107 }
1108
1109 struct thunk {
1110         load_mapping_fn fn;
1111         void *context;
1112
1113         struct dm_cache_metadata *cmd;
1114         bool respect_dirty_flags;
1115         bool hints_valid;
1116 };
1117
1118 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1119                              struct dm_cache_policy *policy)
1120 {
1121         const char *policy_name = dm_cache_policy_get_name(policy);
1122         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1123         size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1124
1125         /*
1126          * Ensure policy names match.
1127          */
1128         if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1129                 return false;
1130
1131         /*
1132          * Ensure policy major versions match.
1133          */
1134         if (cmd->policy_version[0] != policy_version[0])
1135                 return false;
1136
1137         /*
1138          * Ensure policy hint sizes match.
1139          */
1140         if (cmd->policy_hint_size != policy_hint_size)
1141                 return false;
1142
1143         return true;
1144 }
1145
1146 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1147 {
1148         return cmd->hint_root && cmd->policy_hint_size;
1149 }
1150
1151 static bool hints_array_available(struct dm_cache_metadata *cmd,
1152                                   struct dm_cache_policy *policy)
1153 {
1154         return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1155                 hints_array_initialized(cmd);
1156 }
1157
1158 static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1159 {
1160         int r = 0;
1161         bool dirty;
1162         __le64 value;
1163         __le32 hint_value = 0;
1164         dm_oblock_t oblock;
1165         unsigned flags;
1166         struct thunk *thunk = context;
1167         struct dm_cache_metadata *cmd = thunk->cmd;
1168
1169         memcpy(&value, leaf, sizeof(value));
1170         unpack_value(value, &oblock, &flags);
1171
1172         if (flags & M_VALID) {
1173                 if (thunk->hints_valid) {
1174                         r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1175                                                cblock, &hint_value);
1176                         if (r && r != -ENODATA)
1177                                 return r;
1178                 }
1179
1180                 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1181                 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1182                               dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1183         }
1184
1185         return r;
1186 }
1187
1188 static int __load_mappings(struct dm_cache_metadata *cmd,
1189                            struct dm_cache_policy *policy,
1190                            load_mapping_fn fn, void *context)
1191 {
1192         struct thunk thunk;
1193
1194         thunk.fn = fn;
1195         thunk.context = context;
1196
1197         thunk.cmd = cmd;
1198         thunk.respect_dirty_flags = cmd->clean_when_opened;
1199         thunk.hints_valid = hints_array_available(cmd, policy);
1200
1201         return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1202 }
1203
1204 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1205                            struct dm_cache_policy *policy,
1206                            load_mapping_fn fn, void *context)
1207 {
1208         int r;
1209
1210         READ_LOCK(cmd);
1211         r = __load_mappings(cmd, policy, fn, context);
1212         READ_UNLOCK(cmd);
1213
1214         return r;
1215 }
1216
1217 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1218 {
1219         int r = 0;
1220         __le64 value;
1221         dm_oblock_t oblock;
1222         unsigned flags;
1223
1224         memcpy(&value, leaf, sizeof(value));
1225         unpack_value(value, &oblock, &flags);
1226
1227         return r;
1228 }
1229
1230 static int __dump_mappings(struct dm_cache_metadata *cmd)
1231 {
1232         return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1233 }
1234
1235 void dm_cache_dump(struct dm_cache_metadata *cmd)
1236 {
1237         READ_LOCK_VOID(cmd);
1238         __dump_mappings(cmd);
1239         READ_UNLOCK(cmd);
1240 }
1241
1242 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1243 {
1244         int r;
1245
1246         READ_LOCK(cmd);
1247         r = cmd->changed;
1248         READ_UNLOCK(cmd);
1249
1250         return r;
1251 }
1252
1253 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1254 {
1255         int r;
1256         unsigned flags;
1257         dm_oblock_t oblock;
1258         __le64 value;
1259
1260         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1261         if (r)
1262                 return r;
1263
1264         unpack_value(value, &oblock, &flags);
1265
1266         if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1267                 /* nothing to be done */
1268                 return 0;
1269
1270         value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1271         __dm_bless_for_disk(&value);
1272
1273         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1274                                &value, &cmd->root);
1275         if (r)
1276                 return r;
1277
1278         cmd->changed = true;
1279         return 0;
1280
1281 }
1282
1283 int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1284                        dm_cblock_t cblock, bool dirty)
1285 {
1286         int r;
1287
1288         WRITE_LOCK(cmd);
1289         r = __dirty(cmd, cblock, dirty);
1290         WRITE_UNLOCK(cmd);
1291
1292         return r;
1293 }
1294
1295 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1296                                  struct dm_cache_statistics *stats)
1297 {
1298         READ_LOCK_VOID(cmd);
1299         *stats = cmd->stats;
1300         READ_UNLOCK(cmd);
1301 }
1302
1303 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1304                                  struct dm_cache_statistics *stats)
1305 {
1306         WRITE_LOCK_VOID(cmd);
1307         cmd->stats = *stats;
1308         WRITE_UNLOCK(cmd);
1309 }
1310
1311 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1312 {
1313         int r;
1314         flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1315                                  clear_clean_shutdown);
1316
1317         WRITE_LOCK(cmd);
1318         r = __commit_transaction(cmd, mutator);
1319         if (r)
1320                 goto out;
1321
1322         r = __begin_transaction(cmd);
1323
1324 out:
1325         WRITE_UNLOCK(cmd);
1326         return r;
1327 }
1328
1329 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1330                                            dm_block_t *result)
1331 {
1332         int r = -EINVAL;
1333
1334         READ_LOCK(cmd);
1335         r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1336         READ_UNLOCK(cmd);
1337
1338         return r;
1339 }
1340
1341 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1342                                    dm_block_t *result)
1343 {
1344         int r = -EINVAL;
1345
1346         READ_LOCK(cmd);
1347         r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1348         READ_UNLOCK(cmd);
1349
1350         return r;
1351 }
1352
1353 /*----------------------------------------------------------------*/
1354
1355 static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1356 {
1357         int r;
1358         __le32 value;
1359         size_t hint_size;
1360         const char *policy_name = dm_cache_policy_get_name(policy);
1361         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1362
1363         if (!policy_name[0] ||
1364             (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1365                 return -EINVAL;
1366
1367         if (!policy_unchanged(cmd, policy)) {
1368                 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1369                 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1370
1371                 hint_size = dm_cache_policy_get_hint_size(policy);
1372                 if (!hint_size)
1373                         return 0; /* short-circuit hints initialization */
1374                 cmd->policy_hint_size = hint_size;
1375
1376                 if (cmd->hint_root) {
1377                         r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1378                         if (r)
1379                                 return r;
1380                 }
1381
1382                 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1383                 if (r)
1384                         return r;
1385
1386                 value = cpu_to_le32(0);
1387                 __dm_bless_for_disk(&value);
1388                 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1389                                     from_cblock(cmd->cache_blocks),
1390                                     &value, &cmd->hint_root);
1391                 if (r)
1392                         return r;
1393         }
1394
1395         return 0;
1396 }
1397
1398 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1399 {
1400         struct dm_cache_metadata *cmd = context;
1401         __le32 value = cpu_to_le32(hint);
1402         int r;
1403
1404         __dm_bless_for_disk(&value);
1405
1406         r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1407                                from_cblock(cblock), &value, &cmd->hint_root);
1408         cmd->changed = true;
1409
1410         return r;
1411 }
1412
1413 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1414 {
1415         int r;
1416
1417         r = begin_hints(cmd, policy);
1418         if (r) {
1419                 DMERR("begin_hints failed");
1420                 return r;
1421         }
1422
1423         return policy_walk_mappings(policy, save_hint, cmd);
1424 }
1425
1426 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1427 {
1428         int r;
1429
1430         WRITE_LOCK(cmd);
1431         r = write_hints(cmd, policy);
1432         WRITE_UNLOCK(cmd);
1433
1434         return r;
1435 }
1436
1437 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1438 {
1439         int r;
1440
1441         READ_LOCK(cmd);
1442         r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1443         READ_UNLOCK(cmd);
1444
1445         return r;
1446 }
1447
1448 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1449 {
1450         WRITE_LOCK_VOID(cmd);
1451         dm_bm_set_read_only(cmd->bm);
1452         WRITE_UNLOCK(cmd);
1453 }
1454
1455 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1456 {
1457         WRITE_LOCK_VOID(cmd);
1458         dm_bm_set_read_write(cmd->bm);
1459         WRITE_UNLOCK(cmd);
1460 }
1461
1462 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1463 {
1464         int r;
1465         struct dm_block *sblock;
1466         struct cache_disk_superblock *disk_super;
1467
1468         WRITE_LOCK(cmd);
1469         set_bit(NEEDS_CHECK, &cmd->flags);
1470
1471         r = superblock_lock(cmd, &sblock);
1472         if (r) {
1473                 DMERR("couldn't read superblock");
1474                 goto out;
1475         }
1476
1477         disk_super = dm_block_data(sblock);
1478         disk_super->flags = cpu_to_le32(cmd->flags);
1479
1480         dm_bm_unlock(sblock);
1481
1482 out:
1483         WRITE_UNLOCK(cmd);
1484         return r;
1485 }
1486
1487 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1488 {
1489         READ_LOCK(cmd);
1490         *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1491         READ_UNLOCK(cmd);
1492
1493         return 0;
1494 }
1495
1496 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1497 {
1498         int r;
1499
1500         WRITE_LOCK(cmd);
1501         __destroy_persistent_data_objects(cmd);
1502         r = __create_persistent_data_objects(cmd, false);
1503         if (r)
1504                 cmd->fail_io = true;
1505         WRITE_UNLOCK(cmd);
1506
1507         return r;
1508 }