2 * Copyright (C) 2012 Red Hat, Inc.
4 * This file is released under the GPL.
7 #include "dm-cache-metadata.h"
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"
15 #include <linux/device-mapper.h>
17 /*----------------------------------------------------------------*/
19 #define DM_MSG_PREFIX "cache metadata"
21 #define CACHE_SUPERBLOCK_MAGIC 06142003
22 #define CACHE_SUPERBLOCK_LOCATION 0
25 * defines a range of metadata versions that this module can handle.
27 #define MIN_CACHE_VERSION 1
28 #define MAX_CACHE_VERSION 1
30 #define CACHE_METADATA_CACHE_SIZE 64
33 * 3 for btree insert +
34 * 2 for btree lookup used within space map
36 #define CACHE_MAX_CONCURRENT_LOCKS 5
37 #define SPACE_MAP_ROOT_SIZE 128
39 enum superblock_flag_bits {
40 /* for spotting crashes that would invalidate the dirty bitset */
42 /* metadata must be checked using the tools */
47 * Each mapping from cache block -> origin block carries a set of flags.
51 * A valid mapping. Because we're using an array we clear this
52 * flag for an non existant mapping.
57 * The data on the cache is different from that on the origin.
62 struct cache_disk_superblock {
71 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
72 __le32 policy_hint_size;
74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
79 __le64 discard_block_size;
80 __le64 discard_nr_blocks;
82 __le32 data_block_size;
83 __le32 metadata_block_size;
87 __le32 compat_ro_flags;
88 __le32 incompat_flags;
95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
98 struct dm_cache_metadata {
100 struct list_head list;
102 struct block_device *bdev;
103 struct dm_block_manager *bm;
104 struct dm_space_map *metadata_sm;
105 struct dm_transaction_manager *tm;
107 struct dm_array_info info;
108 struct dm_array_info hint_info;
109 struct dm_disk_bitset discard_info;
111 struct rw_semaphore root_lock;
114 dm_block_t hint_root;
115 dm_block_t discard_root;
117 sector_t discard_block_size;
118 dm_dblock_t discard_nr_blocks;
120 sector_t data_block_size;
121 dm_cblock_t cache_blocks;
123 bool clean_when_opened:1;
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;
131 * Reading the space map root can fail, so we read it into this
132 * buffer before the superblock is locked and updated.
134 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
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
145 /*-------------------------------------------------------------------
146 * superblock validator
147 *-----------------------------------------------------------------*/
149 #define SUPERBLOCK_CSUM_XOR 9031977
151 static void sb_prepare_for_write(struct dm_block_validator *v,
153 size_t sb_block_size)
155 struct cache_disk_superblock *disk_super = dm_block_data(b);
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));
163 static int check_metadata_version(struct cache_disk_superblock *disk_super)
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);
175 static int sb_check(struct dm_block_validator *v,
177 size_t sb_block_size)
179 struct cache_disk_superblock *disk_super = dm_block_data(b);
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));
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);
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));
205 return check_metadata_version(disk_super);
208 static struct dm_block_validator sb_validator = {
209 .name = "superblock",
210 .prepare_for_write = sb_prepare_for_write,
214 /*----------------------------------------------------------------*/
216 static int superblock_read_lock(struct dm_cache_metadata *cmd,
217 struct dm_block **sblock)
219 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
220 &sb_validator, sblock);
223 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
224 struct dm_block **sblock)
226 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
227 &sb_validator, sblock);
230 static int superblock_lock(struct dm_cache_metadata *cmd,
231 struct dm_block **sblock)
233 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
234 &sb_validator, sblock);
237 /*----------------------------------------------------------------*/
239 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
244 __le64 *data_le, zero = cpu_to_le64(0);
245 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
248 * We can't use a validator here - it may be all zeroes.
250 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
254 data_le = dm_block_data(b);
256 for (i = 0; i < sb_block_size; i++) {
257 if (data_le[i] != zero) {
263 return dm_bm_unlock(b);
266 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
268 struct dm_btree_value_type vt;
271 vt.size = sizeof(__le64);
275 dm_array_info_init(&cmd->info, cmd->tm, &vt);
277 if (cmd->policy_hint_size) {
278 vt.size = sizeof(__le32);
279 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
283 static int __save_sm_root(struct dm_cache_metadata *cmd)
288 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
292 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
296 static void __copy_sm_root(struct dm_cache_metadata *cmd,
297 struct cache_disk_superblock *disk_super)
299 memcpy(&disk_super->metadata_space_map_root,
300 &cmd->metadata_space_map_root,
301 sizeof(cmd->metadata_space_map_root));
304 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
307 struct dm_block *sblock;
308 struct cache_disk_superblock *disk_super;
309 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
311 /* FIXME: see if we can lose the max sectors limit */
312 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
313 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
315 r = dm_tm_pre_commit(cmd->tm);
320 * dm_sm_copy_root() can fail. So we need to do it before we start
321 * updating the superblock.
323 r = __save_sm_root(cmd);
327 r = superblock_lock_zero(cmd, &sblock);
331 disk_super = dm_block_data(sblock);
332 disk_super->flags = 0;
333 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
334 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
335 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
336 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
337 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
338 disk_super->policy_hint_size = 0;
340 __copy_sm_root(cmd, disk_super);
342 disk_super->mapping_root = cpu_to_le64(cmd->root);
343 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
344 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
345 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
346 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
347 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
348 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
349 disk_super->cache_blocks = cpu_to_le32(0);
351 disk_super->read_hits = cpu_to_le32(0);
352 disk_super->read_misses = cpu_to_le32(0);
353 disk_super->write_hits = cpu_to_le32(0);
354 disk_super->write_misses = cpu_to_le32(0);
356 return dm_tm_commit(cmd->tm, sblock);
359 static int __format_metadata(struct dm_cache_metadata *cmd)
363 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
364 &cmd->tm, &cmd->metadata_sm);
366 DMERR("tm_create_with_sm failed");
370 __setup_mapping_info(cmd);
372 r = dm_array_empty(&cmd->info, &cmd->root);
376 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
378 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
382 cmd->discard_block_size = 0;
383 cmd->discard_nr_blocks = 0;
385 r = __write_initial_superblock(cmd);
389 cmd->clean_when_opened = true;
393 dm_tm_destroy(cmd->tm);
394 dm_sm_destroy(cmd->metadata_sm);
399 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
400 struct dm_cache_metadata *cmd)
404 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
406 DMERR("could not access metadata due to unsupported optional features (%lx).",
407 (unsigned long)features);
412 * Check for read-only metadata to skip the following RDWR checks.
414 if (get_disk_ro(cmd->bdev->bd_disk))
417 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
419 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
420 (unsigned long)features);
427 static int __open_metadata(struct dm_cache_metadata *cmd)
430 struct dm_block *sblock;
431 struct cache_disk_superblock *disk_super;
432 unsigned long sb_flags;
434 r = superblock_read_lock(cmd, &sblock);
436 DMERR("couldn't read lock superblock");
440 disk_super = dm_block_data(sblock);
442 /* Verify the data block size hasn't changed */
443 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
444 DMERR("changing the data block size (from %u to %llu) is not supported",
445 le32_to_cpu(disk_super->data_block_size),
446 (unsigned long long)cmd->data_block_size);
451 r = __check_incompat_features(disk_super, cmd);
455 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
456 disk_super->metadata_space_map_root,
457 sizeof(disk_super->metadata_space_map_root),
458 &cmd->tm, &cmd->metadata_sm);
460 DMERR("tm_open_with_sm failed");
464 __setup_mapping_info(cmd);
465 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
466 sb_flags = le32_to_cpu(disk_super->flags);
467 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
468 return dm_bm_unlock(sblock);
471 dm_bm_unlock(sblock);
475 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
479 bool unformatted = false;
481 r = __superblock_all_zeroes(cmd->bm, &unformatted);
486 return format_device ? __format_metadata(cmd) : -EPERM;
488 return __open_metadata(cmd);
491 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
492 bool may_format_device)
495 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
496 CACHE_METADATA_CACHE_SIZE,
497 CACHE_MAX_CONCURRENT_LOCKS);
498 if (IS_ERR(cmd->bm)) {
499 DMERR("could not create block manager");
500 return PTR_ERR(cmd->bm);
503 r = __open_or_format_metadata(cmd, may_format_device);
505 dm_block_manager_destroy(cmd->bm);
510 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
512 dm_sm_destroy(cmd->metadata_sm);
513 dm_tm_destroy(cmd->tm);
514 dm_block_manager_destroy(cmd->bm);
517 typedef unsigned long (*flags_mutator)(unsigned long);
519 static void update_flags(struct cache_disk_superblock *disk_super,
520 flags_mutator mutator)
522 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
523 disk_super->flags = cpu_to_le32(sb_flags);
526 static unsigned long set_clean_shutdown(unsigned long flags)
528 set_bit(CLEAN_SHUTDOWN, &flags);
532 static unsigned long clear_clean_shutdown(unsigned long flags)
534 clear_bit(CLEAN_SHUTDOWN, &flags);
538 static void read_superblock_fields(struct dm_cache_metadata *cmd,
539 struct cache_disk_superblock *disk_super)
541 cmd->flags = le32_to_cpu(disk_super->flags);
542 cmd->root = le64_to_cpu(disk_super->mapping_root);
543 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
544 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
545 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
546 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
547 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
548 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
549 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
550 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
551 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
552 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
553 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
555 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
556 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
557 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
558 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
560 cmd->changed = false;
564 * The mutator updates the superblock flags.
566 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
567 flags_mutator mutator)
570 struct cache_disk_superblock *disk_super;
571 struct dm_block *sblock;
573 r = superblock_lock(cmd, &sblock);
577 disk_super = dm_block_data(sblock);
578 update_flags(disk_super, mutator);
579 read_superblock_fields(cmd, disk_super);
580 dm_bm_unlock(sblock);
582 return dm_bm_flush(cmd->bm);
585 static int __begin_transaction(struct dm_cache_metadata *cmd)
588 struct cache_disk_superblock *disk_super;
589 struct dm_block *sblock;
592 * We re-read the superblock every time. Shouldn't need to do this
595 r = superblock_read_lock(cmd, &sblock);
599 disk_super = dm_block_data(sblock);
600 read_superblock_fields(cmd, disk_super);
601 dm_bm_unlock(sblock);
606 static int __commit_transaction(struct dm_cache_metadata *cmd,
607 flags_mutator mutator)
610 struct cache_disk_superblock *disk_super;
611 struct dm_block *sblock;
614 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
616 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
618 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
623 r = dm_tm_pre_commit(cmd->tm);
627 r = __save_sm_root(cmd);
631 r = superblock_lock(cmd, &sblock);
635 disk_super = dm_block_data(sblock);
637 disk_super->flags = cpu_to_le32(cmd->flags);
639 update_flags(disk_super, mutator);
641 disk_super->mapping_root = cpu_to_le64(cmd->root);
642 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
643 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
644 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
645 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
646 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
647 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
648 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
649 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
650 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
652 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
653 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
654 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
655 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
656 __copy_sm_root(cmd, disk_super);
658 return dm_tm_commit(cmd->tm, sblock);
661 /*----------------------------------------------------------------*/
664 * The mappings are held in a dm-array that has 64-bit values stored in
665 * little-endian format. The index is the cblock, the high 48bits of the
666 * value are the oblock and the low 16 bit the flags.
668 #define FLAGS_MASK ((1 << 16) - 1)
670 static __le64 pack_value(dm_oblock_t block, unsigned flags)
672 uint64_t value = from_oblock(block);
674 value = value | (flags & FLAGS_MASK);
675 return cpu_to_le64(value);
678 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
680 uint64_t value = le64_to_cpu(value_le);
681 uint64_t b = value >> 16;
682 *block = to_oblock(b);
683 *flags = value & FLAGS_MASK;
686 /*----------------------------------------------------------------*/
688 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
689 sector_t data_block_size,
690 bool may_format_device,
691 size_t policy_hint_size)
694 struct dm_cache_metadata *cmd;
696 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
698 DMERR("could not allocate metadata struct");
699 return ERR_PTR(-ENOMEM);
702 atomic_set(&cmd->ref_count, 1);
703 init_rwsem(&cmd->root_lock);
705 cmd->data_block_size = data_block_size;
706 cmd->cache_blocks = 0;
707 cmd->policy_hint_size = policy_hint_size;
709 cmd->fail_io = false;
711 r = __create_persistent_data_objects(cmd, may_format_device);
717 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
719 dm_cache_metadata_close(cmd);
727 * We keep a little list of ref counted metadata objects to prevent two
728 * different target instances creating separate bufio instances. This is
729 * an issue if a table is reloaded before the suspend.
731 static DEFINE_MUTEX(table_lock);
732 static LIST_HEAD(table);
734 static struct dm_cache_metadata *lookup(struct block_device *bdev)
736 struct dm_cache_metadata *cmd;
738 list_for_each_entry(cmd, &table, list)
739 if (cmd->bdev == bdev) {
740 atomic_inc(&cmd->ref_count);
747 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
748 sector_t data_block_size,
749 bool may_format_device,
750 size_t policy_hint_size)
752 struct dm_cache_metadata *cmd, *cmd2;
754 mutex_lock(&table_lock);
756 mutex_unlock(&table_lock);
761 cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
763 mutex_lock(&table_lock);
766 mutex_unlock(&table_lock);
767 __destroy_persistent_data_objects(cmd);
771 list_add(&cmd->list, &table);
772 mutex_unlock(&table_lock);
778 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
780 if (cmd->data_block_size != data_block_size) {
781 DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",
782 (unsigned long long) data_block_size,
783 (unsigned long long) cmd->data_block_size);
790 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
791 sector_t data_block_size,
792 bool may_format_device,
793 size_t policy_hint_size)
795 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
796 may_format_device, policy_hint_size);
798 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
799 dm_cache_metadata_close(cmd);
800 return ERR_PTR(-EINVAL);
806 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
808 if (atomic_dec_and_test(&cmd->ref_count)) {
809 mutex_lock(&table_lock);
810 list_del(&cmd->list);
811 mutex_unlock(&table_lock);
814 __destroy_persistent_data_objects(cmd);
820 * Checks that the given cache block is either unmapped or clean.
822 static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
830 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
832 DMERR("block_unmapped_or_clean failed");
836 unpack_value(value, &ob, &flags);
837 *result = !((flags & M_VALID) && (flags & M_DIRTY));
842 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
843 dm_cblock_t begin, dm_cblock_t end,
849 while (begin != end) {
850 r = block_unmapped_or_clean(cmd, begin, result);
855 DMERR("cache block %llu is dirty",
856 (unsigned long long) from_cblock(begin));
860 begin = to_cblock(from_cblock(begin) + 1);
866 #define WRITE_LOCK(cmd) \
867 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) \
869 down_write(&cmd->root_lock)
871 #define WRITE_LOCK_VOID(cmd) \
872 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) \
874 down_write(&cmd->root_lock)
876 #define WRITE_UNLOCK(cmd) \
877 up_write(&cmd->root_lock)
879 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
883 __le64 null_mapping = pack_value(0, 0);
886 __dm_bless_for_disk(&null_mapping);
888 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
889 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
891 __dm_unbless_for_disk(&null_mapping);
896 DMERR("unable to shrink cache due to dirty blocks");
898 __dm_unbless_for_disk(&null_mapping);
903 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
904 from_cblock(new_cache_size),
905 &null_mapping, &cmd->root);
907 cmd->cache_blocks = new_cache_size;
916 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
917 sector_t discard_block_size,
918 dm_dblock_t new_nr_entries)
923 r = dm_bitset_resize(&cmd->discard_info,
925 from_dblock(cmd->discard_nr_blocks),
926 from_dblock(new_nr_entries),
927 false, &cmd->discard_root);
929 cmd->discard_block_size = discard_block_size;
930 cmd->discard_nr_blocks = new_nr_entries;
939 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
941 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
942 from_dblock(b), &cmd->discard_root);
945 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
947 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
948 from_dblock(b), &cmd->discard_root);
951 static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
954 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
955 from_dblock(b), &cmd->discard_root,
959 static int __discard(struct dm_cache_metadata *cmd,
960 dm_dblock_t dblock, bool discard)
964 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
972 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
973 dm_dblock_t dblock, bool discard)
978 r = __discard(cmd, dblock, discard);
984 static int __load_discards(struct dm_cache_metadata *cmd,
985 load_discard_fn fn, void *context)
991 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
992 dm_dblock_t dblock = to_dblock(b);
994 if (cmd->clean_when_opened) {
995 r = __is_discarded(cmd, dblock, &discard);
1001 r = fn(context, cmd->discard_block_size, dblock, discard);
1009 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1010 load_discard_fn fn, void *context)
1014 down_read(&cmd->root_lock);
1015 r = __load_discards(cmd, fn, context);
1016 up_read(&cmd->root_lock);
1021 dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
1025 down_read(&cmd->root_lock);
1026 r = cmd->cache_blocks;
1027 up_read(&cmd->root_lock);
1032 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1035 __le64 value = pack_value(0, 0);
1037 __dm_bless_for_disk(&value);
1038 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1039 &value, &cmd->root);
1043 cmd->changed = true;
1047 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1052 r = __remove(cmd, cblock);
1058 static int __insert(struct dm_cache_metadata *cmd,
1059 dm_cblock_t cblock, dm_oblock_t oblock)
1062 __le64 value = pack_value(oblock, M_VALID);
1063 __dm_bless_for_disk(&value);
1065 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1066 &value, &cmd->root);
1070 cmd->changed = true;
1074 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1075 dm_cblock_t cblock, dm_oblock_t oblock)
1080 r = __insert(cmd, cblock, oblock);
1090 struct dm_cache_metadata *cmd;
1091 bool respect_dirty_flags;
1095 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1096 struct dm_cache_policy *policy)
1098 const char *policy_name = dm_cache_policy_get_name(policy);
1099 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1100 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1103 * Ensure policy names match.
1105 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1109 * Ensure policy major versions match.
1111 if (cmd->policy_version[0] != policy_version[0])
1115 * Ensure policy hint sizes match.
1117 if (cmd->policy_hint_size != policy_hint_size)
1123 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1125 return cmd->hint_root && cmd->policy_hint_size;
1128 static bool hints_array_available(struct dm_cache_metadata *cmd,
1129 struct dm_cache_policy *policy)
1131 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1132 hints_array_initialized(cmd);
1135 static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1140 __le32 hint_value = 0;
1143 struct thunk *thunk = context;
1144 struct dm_cache_metadata *cmd = thunk->cmd;
1146 memcpy(&value, leaf, sizeof(value));
1147 unpack_value(value, &oblock, &flags);
1149 if (flags & M_VALID) {
1150 if (thunk->hints_valid) {
1151 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1152 cblock, &hint_value);
1153 if (r && r != -ENODATA)
1157 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1158 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1159 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1165 static int __load_mappings(struct dm_cache_metadata *cmd,
1166 struct dm_cache_policy *policy,
1167 load_mapping_fn fn, void *context)
1172 thunk.context = context;
1175 thunk.respect_dirty_flags = cmd->clean_when_opened;
1176 thunk.hints_valid = hints_array_available(cmd, policy);
1178 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1181 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1182 struct dm_cache_policy *policy,
1183 load_mapping_fn fn, void *context)
1187 down_read(&cmd->root_lock);
1188 r = __load_mappings(cmd, policy, fn, context);
1189 up_read(&cmd->root_lock);
1194 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1201 memcpy(&value, leaf, sizeof(value));
1202 unpack_value(value, &oblock, &flags);
1207 static int __dump_mappings(struct dm_cache_metadata *cmd)
1209 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1212 void dm_cache_dump(struct dm_cache_metadata *cmd)
1214 down_read(&cmd->root_lock);
1215 __dump_mappings(cmd);
1216 up_read(&cmd->root_lock);
1219 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1223 down_read(&cmd->root_lock);
1225 up_read(&cmd->root_lock);
1230 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1237 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1241 unpack_value(value, &oblock, &flags);
1243 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1244 /* nothing to be done */
1247 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1248 __dm_bless_for_disk(&value);
1250 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1251 &value, &cmd->root);
1255 cmd->changed = true;
1260 int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1261 dm_cblock_t cblock, bool dirty)
1266 r = __dirty(cmd, cblock, dirty);
1272 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1273 struct dm_cache_statistics *stats)
1275 down_read(&cmd->root_lock);
1276 *stats = cmd->stats;
1277 up_read(&cmd->root_lock);
1280 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1281 struct dm_cache_statistics *stats)
1283 WRITE_LOCK_VOID(cmd);
1284 cmd->stats = *stats;
1288 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1291 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1292 clear_clean_shutdown);
1295 r = __commit_transaction(cmd, mutator);
1299 r = __begin_transaction(cmd);
1306 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1311 down_read(&cmd->root_lock);
1312 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1313 up_read(&cmd->root_lock);
1318 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1323 down_read(&cmd->root_lock);
1324 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1325 up_read(&cmd->root_lock);
1330 /*----------------------------------------------------------------*/
1332 static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1337 const char *policy_name = dm_cache_policy_get_name(policy);
1338 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1340 if (!policy_name[0] ||
1341 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1344 if (!policy_unchanged(cmd, policy)) {
1345 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1346 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1348 hint_size = dm_cache_policy_get_hint_size(policy);
1350 return 0; /* short-circuit hints initialization */
1351 cmd->policy_hint_size = hint_size;
1353 if (cmd->hint_root) {
1354 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1359 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1363 value = cpu_to_le32(0);
1364 __dm_bless_for_disk(&value);
1365 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1366 from_cblock(cmd->cache_blocks),
1367 &value, &cmd->hint_root);
1375 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1377 struct dm_cache_metadata *cmd = context;
1378 __le32 value = cpu_to_le32(hint);
1381 __dm_bless_for_disk(&value);
1383 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1384 from_cblock(cblock), &value, &cmd->hint_root);
1385 cmd->changed = true;
1390 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1394 r = begin_hints(cmd, policy);
1396 DMERR("begin_hints failed");
1400 return policy_walk_mappings(policy, save_hint, cmd);
1403 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1408 r = write_hints(cmd, policy);
1414 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1416 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1419 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1421 WRITE_LOCK_VOID(cmd);
1422 dm_bm_set_read_only(cmd->bm);
1426 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1428 WRITE_LOCK_VOID(cmd);
1429 dm_bm_set_read_write(cmd->bm);
1433 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1436 struct dm_block *sblock;
1437 struct cache_disk_superblock *disk_super;
1440 * We ignore fail_io for this function.
1442 down_write(&cmd->root_lock);
1443 set_bit(NEEDS_CHECK, &cmd->flags);
1445 r = superblock_lock(cmd, &sblock);
1447 DMERR("couldn't read superblock");
1451 disk_super = dm_block_data(sblock);
1452 disk_super->flags = cpu_to_le32(cmd->flags);
1454 dm_bm_unlock(sblock);
1457 up_write(&cmd->root_lock);
1461 bool dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd)
1465 down_read(&cmd->root_lock);
1466 needs_check = !!test_bit(NEEDS_CHECK, &cmd->flags);
1467 up_read(&cmd->root_lock);
1472 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1477 __destroy_persistent_data_objects(cmd);
1478 r = __create_persistent_data_objects(cmd, false);
1480 cmd->fail_io = true;