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 2
31 * 3 for btree insert +
32 * 2 for btree lookup used within space map
34 #define CACHE_MAX_CONCURRENT_LOCKS 5
35 #define SPACE_MAP_ROOT_SIZE 128
37 enum superblock_flag_bits {
38 /* for spotting crashes that would invalidate the dirty bitset */
40 /* metadata must be checked using the tools */
45 * Each mapping from cache block -> origin block carries a set of flags.
49 * A valid mapping. Because we're using an array we clear this
50 * flag for an non existant mapping.
55 * The data on the cache is different from that on the origin.
56 * This flag is only used by metadata format 1.
61 struct cache_disk_superblock {
70 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
71 __le32 policy_hint_size;
73 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
78 __le64 discard_block_size;
79 __le64 discard_nr_blocks;
81 __le32 data_block_size;
82 __le32 metadata_block_size;
86 __le32 compat_ro_flags;
87 __le32 incompat_flags;
94 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
97 * Metadata format 2 fields.
102 struct dm_cache_metadata {
104 struct list_head list;
107 struct block_device *bdev;
108 struct dm_block_manager *bm;
109 struct dm_space_map *metadata_sm;
110 struct dm_transaction_manager *tm;
112 struct dm_array_info info;
113 struct dm_array_info hint_info;
114 struct dm_disk_bitset discard_info;
116 struct rw_semaphore root_lock;
119 dm_block_t hint_root;
120 dm_block_t discard_root;
122 sector_t discard_block_size;
123 dm_dblock_t discard_nr_blocks;
125 sector_t data_block_size;
126 dm_cblock_t cache_blocks;
128 bool clean_when_opened:1;
130 char policy_name[CACHE_POLICY_NAME_SIZE];
131 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
132 size_t policy_hint_size;
133 struct dm_cache_statistics stats;
136 * Reading the space map root can fail, so we read it into this
137 * buffer before the superblock is locked and updated.
139 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
142 * Set if a transaction has to be aborted but the attempt to roll
143 * back to the previous (good) transaction failed. The only
144 * metadata operation permissible in this state is the closing of
150 * Metadata format 2 fields.
152 dm_block_t dirty_root;
153 struct dm_disk_bitset dirty_info;
156 * These structures are used when loading metadata. They're too
157 * big to put on the stack.
159 struct dm_array_cursor mapping_cursor;
160 struct dm_array_cursor hint_cursor;
161 struct dm_bitset_cursor dirty_cursor;
164 /*-------------------------------------------------------------------
165 * superblock validator
166 *-----------------------------------------------------------------*/
168 #define SUPERBLOCK_CSUM_XOR 9031977
170 static void sb_prepare_for_write(struct dm_block_validator *v,
172 size_t sb_block_size)
174 struct cache_disk_superblock *disk_super = dm_block_data(b);
176 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
177 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
178 sb_block_size - sizeof(__le32),
179 SUPERBLOCK_CSUM_XOR));
182 static int check_metadata_version(struct cache_disk_superblock *disk_super)
184 uint32_t metadata_version = le32_to_cpu(disk_super->version);
186 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
187 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
188 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
195 static int sb_check(struct dm_block_validator *v,
197 size_t sb_block_size)
199 struct cache_disk_superblock *disk_super = dm_block_data(b);
202 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
203 DMERR("sb_check failed: blocknr %llu: wanted %llu",
204 le64_to_cpu(disk_super->blocknr),
205 (unsigned long long)dm_block_location(b));
209 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
210 DMERR("sb_check failed: magic %llu: wanted %llu",
211 le64_to_cpu(disk_super->magic),
212 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
216 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
217 sb_block_size - sizeof(__le32),
218 SUPERBLOCK_CSUM_XOR));
219 if (csum_le != disk_super->csum) {
220 DMERR("sb_check failed: csum %u: wanted %u",
221 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
225 return check_metadata_version(disk_super);
228 static struct dm_block_validator sb_validator = {
229 .name = "superblock",
230 .prepare_for_write = sb_prepare_for_write,
234 /*----------------------------------------------------------------*/
236 static int superblock_read_lock(struct dm_cache_metadata *cmd,
237 struct dm_block **sblock)
239 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
240 &sb_validator, sblock);
243 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
244 struct dm_block **sblock)
246 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
247 &sb_validator, sblock);
250 static int superblock_lock(struct dm_cache_metadata *cmd,
251 struct dm_block **sblock)
253 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
254 &sb_validator, sblock);
257 /*----------------------------------------------------------------*/
259 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
264 __le64 *data_le, zero = cpu_to_le64(0);
265 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
268 * We can't use a validator here - it may be all zeroes.
270 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
274 data_le = dm_block_data(b);
276 for (i = 0; i < sb_block_size; i++) {
277 if (data_le[i] != zero) {
288 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
290 struct dm_btree_value_type vt;
293 vt.size = sizeof(__le64);
297 dm_array_info_init(&cmd->info, cmd->tm, &vt);
299 if (cmd->policy_hint_size) {
300 vt.size = sizeof(__le32);
301 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
305 static int __save_sm_root(struct dm_cache_metadata *cmd)
310 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
314 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
318 static void __copy_sm_root(struct dm_cache_metadata *cmd,
319 struct cache_disk_superblock *disk_super)
321 memcpy(&disk_super->metadata_space_map_root,
322 &cmd->metadata_space_map_root,
323 sizeof(cmd->metadata_space_map_root));
326 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
328 return cmd->version >= 2;
331 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
334 struct dm_block *sblock;
335 struct cache_disk_superblock *disk_super;
336 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
338 /* FIXME: see if we can lose the max sectors limit */
339 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
340 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
342 r = dm_tm_pre_commit(cmd->tm);
347 * dm_sm_copy_root() can fail. So we need to do it before we start
348 * updating the superblock.
350 r = __save_sm_root(cmd);
354 r = superblock_lock_zero(cmd, &sblock);
358 disk_super = dm_block_data(sblock);
359 disk_super->flags = 0;
360 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
361 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
362 disk_super->version = cpu_to_le32(cmd->version);
363 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
364 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
365 disk_super->policy_hint_size = 0;
367 __copy_sm_root(cmd, disk_super);
369 disk_super->mapping_root = cpu_to_le64(cmd->root);
370 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
371 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
372 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
373 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
374 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
375 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
376 disk_super->cache_blocks = cpu_to_le32(0);
378 disk_super->read_hits = cpu_to_le32(0);
379 disk_super->read_misses = cpu_to_le32(0);
380 disk_super->write_hits = cpu_to_le32(0);
381 disk_super->write_misses = cpu_to_le32(0);
383 if (separate_dirty_bits(cmd))
384 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
386 return dm_tm_commit(cmd->tm, sblock);
389 static int __format_metadata(struct dm_cache_metadata *cmd)
393 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
394 &cmd->tm, &cmd->metadata_sm);
396 DMERR("tm_create_with_sm failed");
400 __setup_mapping_info(cmd);
402 r = dm_array_empty(&cmd->info, &cmd->root);
406 if (separate_dirty_bits(cmd)) {
407 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
408 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
413 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
414 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
418 cmd->discard_block_size = 0;
419 cmd->discard_nr_blocks = 0;
421 r = __write_initial_superblock(cmd);
425 cmd->clean_when_opened = true;
429 dm_tm_destroy(cmd->tm);
430 dm_sm_destroy(cmd->metadata_sm);
435 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
436 struct dm_cache_metadata *cmd)
438 uint32_t incompat_flags, features;
440 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
441 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
443 DMERR("could not access metadata due to unsupported optional features (%lx).",
444 (unsigned long)features);
449 * Check for read-only metadata to skip the following RDWR checks.
451 if (get_disk_ro(cmd->bdev->bd_disk))
454 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
456 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
457 (unsigned long)features);
464 static int __open_metadata(struct dm_cache_metadata *cmd)
467 struct dm_block *sblock;
468 struct cache_disk_superblock *disk_super;
469 unsigned long sb_flags;
471 r = superblock_read_lock(cmd, &sblock);
473 DMERR("couldn't read lock superblock");
477 disk_super = dm_block_data(sblock);
479 /* Verify the data block size hasn't changed */
480 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
481 DMERR("changing the data block size (from %u to %llu) is not supported",
482 le32_to_cpu(disk_super->data_block_size),
483 (unsigned long long)cmd->data_block_size);
488 r = __check_incompat_features(disk_super, cmd);
492 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
493 disk_super->metadata_space_map_root,
494 sizeof(disk_super->metadata_space_map_root),
495 &cmd->tm, &cmd->metadata_sm);
497 DMERR("tm_open_with_sm failed");
501 __setup_mapping_info(cmd);
502 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
503 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
504 sb_flags = le32_to_cpu(disk_super->flags);
505 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
506 dm_bm_unlock(sblock);
511 dm_bm_unlock(sblock);
515 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
519 bool unformatted = false;
521 r = __superblock_all_zeroes(cmd->bm, &unformatted);
526 return format_device ? __format_metadata(cmd) : -EPERM;
528 return __open_metadata(cmd);
531 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
532 bool may_format_device)
535 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
536 CACHE_MAX_CONCURRENT_LOCKS);
537 if (IS_ERR(cmd->bm)) {
538 DMERR("could not create block manager");
539 return PTR_ERR(cmd->bm);
542 r = __open_or_format_metadata(cmd, may_format_device);
544 dm_block_manager_destroy(cmd->bm);
549 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
551 dm_sm_destroy(cmd->metadata_sm);
552 dm_tm_destroy(cmd->tm);
553 dm_block_manager_destroy(cmd->bm);
556 typedef unsigned long (*flags_mutator)(unsigned long);
558 static void update_flags(struct cache_disk_superblock *disk_super,
559 flags_mutator mutator)
561 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
562 disk_super->flags = cpu_to_le32(sb_flags);
565 static unsigned long set_clean_shutdown(unsigned long flags)
567 set_bit(CLEAN_SHUTDOWN, &flags);
571 static unsigned long clear_clean_shutdown(unsigned long flags)
573 clear_bit(CLEAN_SHUTDOWN, &flags);
577 static void read_superblock_fields(struct dm_cache_metadata *cmd,
578 struct cache_disk_superblock *disk_super)
580 cmd->version = le32_to_cpu(disk_super->version);
581 cmd->flags = le32_to_cpu(disk_super->flags);
582 cmd->root = le64_to_cpu(disk_super->mapping_root);
583 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
584 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
585 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
586 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
587 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
588 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
589 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
590 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
591 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
592 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
593 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
595 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
596 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
597 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
598 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
600 if (separate_dirty_bits(cmd))
601 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
603 cmd->changed = false;
607 * The mutator updates the superblock flags.
609 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
610 flags_mutator mutator)
613 struct cache_disk_superblock *disk_super;
614 struct dm_block *sblock;
616 r = superblock_lock(cmd, &sblock);
620 disk_super = dm_block_data(sblock);
621 update_flags(disk_super, mutator);
622 read_superblock_fields(cmd, disk_super);
623 dm_bm_unlock(sblock);
625 return dm_bm_flush(cmd->bm);
628 static int __begin_transaction(struct dm_cache_metadata *cmd)
631 struct cache_disk_superblock *disk_super;
632 struct dm_block *sblock;
635 * We re-read the superblock every time. Shouldn't need to do this
638 r = superblock_read_lock(cmd, &sblock);
642 disk_super = dm_block_data(sblock);
643 read_superblock_fields(cmd, disk_super);
644 dm_bm_unlock(sblock);
649 static int __commit_transaction(struct dm_cache_metadata *cmd,
650 flags_mutator mutator)
653 struct cache_disk_superblock *disk_super;
654 struct dm_block *sblock;
657 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
659 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
661 if (separate_dirty_bits(cmd)) {
662 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
668 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
673 r = dm_tm_pre_commit(cmd->tm);
677 r = __save_sm_root(cmd);
681 r = superblock_lock(cmd, &sblock);
685 disk_super = dm_block_data(sblock);
687 disk_super->flags = cpu_to_le32(cmd->flags);
689 update_flags(disk_super, mutator);
691 disk_super->mapping_root = cpu_to_le64(cmd->root);
692 if (separate_dirty_bits(cmd))
693 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
694 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
695 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
696 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
697 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
698 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
699 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
700 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
701 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
702 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
704 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
705 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
706 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
707 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
708 __copy_sm_root(cmd, disk_super);
710 return dm_tm_commit(cmd->tm, sblock);
713 /*----------------------------------------------------------------*/
716 * The mappings are held in a dm-array that has 64-bit values stored in
717 * little-endian format. The index is the cblock, the high 48bits of the
718 * value are the oblock and the low 16 bit the flags.
720 #define FLAGS_MASK ((1 << 16) - 1)
722 static __le64 pack_value(dm_oblock_t block, unsigned flags)
724 uint64_t value = from_oblock(block);
726 value = value | (flags & FLAGS_MASK);
727 return cpu_to_le64(value);
730 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
732 uint64_t value = le64_to_cpu(value_le);
733 uint64_t b = value >> 16;
734 *block = to_oblock(b);
735 *flags = value & FLAGS_MASK;
738 /*----------------------------------------------------------------*/
740 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
741 sector_t data_block_size,
742 bool may_format_device,
743 size_t policy_hint_size,
744 unsigned metadata_version)
747 struct dm_cache_metadata *cmd;
749 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
751 DMERR("could not allocate metadata struct");
752 return ERR_PTR(-ENOMEM);
755 cmd->version = metadata_version;
756 atomic_set(&cmd->ref_count, 1);
757 init_rwsem(&cmd->root_lock);
759 cmd->data_block_size = data_block_size;
760 cmd->cache_blocks = 0;
761 cmd->policy_hint_size = policy_hint_size;
763 cmd->fail_io = false;
765 r = __create_persistent_data_objects(cmd, may_format_device);
771 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
773 dm_cache_metadata_close(cmd);
781 * We keep a little list of ref counted metadata objects to prevent two
782 * different target instances creating separate bufio instances. This is
783 * an issue if a table is reloaded before the suspend.
785 static DEFINE_MUTEX(table_lock);
786 static LIST_HEAD(table);
788 static struct dm_cache_metadata *lookup(struct block_device *bdev)
790 struct dm_cache_metadata *cmd;
792 list_for_each_entry(cmd, &table, list)
793 if (cmd->bdev == bdev) {
794 atomic_inc(&cmd->ref_count);
801 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
802 sector_t data_block_size,
803 bool may_format_device,
804 size_t policy_hint_size,
805 unsigned metadata_version)
807 struct dm_cache_metadata *cmd, *cmd2;
809 mutex_lock(&table_lock);
811 mutex_unlock(&table_lock);
816 cmd = metadata_open(bdev, data_block_size, may_format_device,
817 policy_hint_size, metadata_version);
819 mutex_lock(&table_lock);
822 mutex_unlock(&table_lock);
823 __destroy_persistent_data_objects(cmd);
827 list_add(&cmd->list, &table);
828 mutex_unlock(&table_lock);
834 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
836 if (cmd->data_block_size != data_block_size) {
837 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
838 (unsigned long long) data_block_size,
839 (unsigned long long) cmd->data_block_size);
846 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
847 sector_t data_block_size,
848 bool may_format_device,
849 size_t policy_hint_size,
850 unsigned metadata_version)
852 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
853 policy_hint_size, metadata_version);
855 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
856 dm_cache_metadata_close(cmd);
857 return ERR_PTR(-EINVAL);
863 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
865 if (atomic_dec_and_test(&cmd->ref_count)) {
866 mutex_lock(&table_lock);
867 list_del(&cmd->list);
868 mutex_unlock(&table_lock);
871 __destroy_persistent_data_objects(cmd);
877 * Checks that the given cache block is either unmapped or clean.
879 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
887 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
891 unpack_value(value, &ob, &flags);
892 *result = !((flags & M_VALID) && (flags & M_DIRTY));
897 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
898 dm_cblock_t begin, dm_cblock_t end,
904 while (begin != end) {
905 r = block_clean_combined_dirty(cmd, begin, result);
907 DMERR("block_clean_combined_dirty failed");
912 DMERR("cache block %llu is dirty",
913 (unsigned long long) from_cblock(begin));
917 begin = to_cblock(from_cblock(begin) + 1);
923 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
924 dm_cblock_t begin, dm_cblock_t end,
931 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
932 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
934 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
938 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
940 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
941 dm_bitset_cursor_end(&cmd->dirty_cursor);
945 while (begin != end) {
947 * We assume that unmapped blocks have their dirty bit
950 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
952 DMERR("%s: cache block %llu is dirty", __func__,
953 (unsigned long long) from_cblock(begin));
954 dm_bitset_cursor_end(&cmd->dirty_cursor);
959 begin = to_cblock(from_cblock(begin) + 1);
963 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
965 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
966 dm_bitset_cursor_end(&cmd->dirty_cursor);
971 dm_bitset_cursor_end(&cmd->dirty_cursor);
976 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
977 dm_cblock_t begin, dm_cblock_t end,
980 if (separate_dirty_bits(cmd))
981 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
983 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
986 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
988 down_write(&cmd->root_lock);
989 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
990 up_write(&cmd->root_lock);
996 #define WRITE_LOCK(cmd) \
998 if (!cmd_write_lock((cmd))) \
1002 #define WRITE_LOCK_VOID(cmd) \
1004 if (!cmd_write_lock((cmd))) \
1008 #define WRITE_UNLOCK(cmd) \
1009 up_write(&(cmd)->root_lock)
1011 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1013 down_read(&cmd->root_lock);
1015 up_read(&cmd->root_lock);
1021 #define READ_LOCK(cmd) \
1023 if (!cmd_read_lock((cmd))) \
1027 #define READ_LOCK_VOID(cmd) \
1029 if (!cmd_read_lock((cmd))) \
1033 #define READ_UNLOCK(cmd) \
1034 up_read(&(cmd)->root_lock)
1036 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1040 __le64 null_mapping = pack_value(0, 0);
1043 __dm_bless_for_disk(&null_mapping);
1045 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1046 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1048 __dm_unbless_for_disk(&null_mapping);
1053 DMERR("unable to shrink cache due to dirty blocks");
1055 __dm_unbless_for_disk(&null_mapping);
1060 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1061 from_cblock(new_cache_size),
1062 &null_mapping, &cmd->root);
1066 if (separate_dirty_bits(cmd)) {
1067 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1068 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1069 false, &cmd->dirty_root);
1074 cmd->cache_blocks = new_cache_size;
1075 cmd->changed = true;
1083 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1084 sector_t discard_block_size,
1085 dm_dblock_t new_nr_entries)
1090 r = dm_bitset_resize(&cmd->discard_info,
1092 from_dblock(cmd->discard_nr_blocks),
1093 from_dblock(new_nr_entries),
1094 false, &cmd->discard_root);
1096 cmd->discard_block_size = discard_block_size;
1097 cmd->discard_nr_blocks = new_nr_entries;
1100 cmd->changed = true;
1106 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1108 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1109 from_dblock(b), &cmd->discard_root);
1112 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1114 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1115 from_dblock(b), &cmd->discard_root);
1118 static int __discard(struct dm_cache_metadata *cmd,
1119 dm_dblock_t dblock, bool discard)
1123 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1127 cmd->changed = true;
1131 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1132 dm_dblock_t dblock, bool discard)
1137 r = __discard(cmd, dblock, discard);
1143 static int __load_discards(struct dm_cache_metadata *cmd,
1144 load_discard_fn fn, void *context)
1148 struct dm_bitset_cursor c;
1150 if (from_dblock(cmd->discard_nr_blocks) == 0)
1154 if (cmd->clean_when_opened) {
1155 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1159 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1160 from_dblock(cmd->discard_nr_blocks), &c);
1164 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1165 r = fn(context, cmd->discard_block_size, to_dblock(b),
1166 dm_bitset_cursor_get_value(&c));
1171 dm_bitset_cursor_end(&c);
1174 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1175 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1184 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1185 load_discard_fn fn, void *context)
1190 r = __load_discards(cmd, fn, context);
1196 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1199 *result = cmd->cache_blocks;
1205 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1208 __le64 value = pack_value(0, 0);
1210 __dm_bless_for_disk(&value);
1211 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1212 &value, &cmd->root);
1216 cmd->changed = true;
1220 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1225 r = __remove(cmd, cblock);
1231 static int __insert(struct dm_cache_metadata *cmd,
1232 dm_cblock_t cblock, dm_oblock_t oblock)
1235 __le64 value = pack_value(oblock, M_VALID);
1236 __dm_bless_for_disk(&value);
1238 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1239 &value, &cmd->root);
1243 cmd->changed = true;
1247 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1248 dm_cblock_t cblock, dm_oblock_t oblock)
1253 r = __insert(cmd, cblock, oblock);
1263 struct dm_cache_metadata *cmd;
1264 bool respect_dirty_flags;
1268 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1269 struct dm_cache_policy *policy)
1271 const char *policy_name = dm_cache_policy_get_name(policy);
1272 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1273 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1276 * Ensure policy names match.
1278 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1282 * Ensure policy major versions match.
1284 if (cmd->policy_version[0] != policy_version[0])
1288 * Ensure policy hint sizes match.
1290 if (cmd->policy_hint_size != policy_hint_size)
1296 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1298 return cmd->hint_root && cmd->policy_hint_size;
1301 static bool hints_array_available(struct dm_cache_metadata *cmd,
1302 struct dm_cache_policy *policy)
1304 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1305 hints_array_initialized(cmd);
1308 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1309 uint64_t cb, bool hints_valid,
1310 struct dm_array_cursor *mapping_cursor,
1311 struct dm_array_cursor *hint_cursor,
1312 load_mapping_fn fn, void *context)
1319 __le64 *mapping_value_le;
1320 __le32 *hint_value_le;
1325 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1326 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1327 unpack_value(mapping, &oblock, &flags);
1329 if (flags & M_VALID) {
1331 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1332 memcpy(&hint, hint_value_le, sizeof(hint));
1335 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1336 le32_to_cpu(hint), hints_valid);
1338 DMERR("policy couldn't load cache block %llu",
1339 (unsigned long long) from_cblock(to_cblock(cb)));
1346 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1347 uint64_t cb, bool hints_valid,
1348 struct dm_array_cursor *mapping_cursor,
1349 struct dm_array_cursor *hint_cursor,
1350 struct dm_bitset_cursor *dirty_cursor,
1351 load_mapping_fn fn, void *context)
1358 __le64 *mapping_value_le;
1359 __le32 *hint_value_le;
1365 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1366 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1367 unpack_value(mapping, &oblock, &flags);
1369 if (flags & M_VALID) {
1371 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1372 memcpy(&hint, hint_value_le, sizeof(hint));
1375 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1376 r = fn(context, oblock, to_cblock(cb), dirty,
1377 le32_to_cpu(hint), hints_valid);
1379 DMERR("policy couldn't load cache block %llu",
1380 (unsigned long long) from_cblock(to_cblock(cb)));
1387 static int __load_mappings(struct dm_cache_metadata *cmd,
1388 struct dm_cache_policy *policy,
1389 load_mapping_fn fn, void *context)
1394 bool hints_valid = hints_array_available(cmd, policy);
1396 if (from_cblock(cmd->cache_blocks) == 0)
1400 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1405 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1407 dm_array_cursor_end(&cmd->mapping_cursor);
1412 if (separate_dirty_bits(cmd)) {
1413 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1414 from_cblock(cmd->cache_blocks),
1415 &cmd->dirty_cursor);
1417 dm_array_cursor_end(&cmd->hint_cursor);
1418 dm_array_cursor_end(&cmd->mapping_cursor);
1423 for (cb = 0; ; cb++) {
1424 if (separate_dirty_bits(cmd))
1425 r = __load_mapping_v2(cmd, cb, hints_valid,
1426 &cmd->mapping_cursor,
1431 r = __load_mapping_v1(cmd, cb, hints_valid,
1432 &cmd->mapping_cursor, &cmd->hint_cursor,
1438 * We need to break out before we move the cursors.
1440 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1443 r = dm_array_cursor_next(&cmd->mapping_cursor);
1445 DMERR("dm_array_cursor_next for mapping failed");
1450 r = dm_array_cursor_next(&cmd->hint_cursor);
1452 DMERR("dm_array_cursor_next for hint failed");
1457 if (separate_dirty_bits(cmd)) {
1458 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1460 DMERR("dm_bitset_cursor_next for dirty failed");
1466 dm_array_cursor_end(&cmd->mapping_cursor);
1468 dm_array_cursor_end(&cmd->hint_cursor);
1470 if (separate_dirty_bits(cmd))
1471 dm_bitset_cursor_end(&cmd->dirty_cursor);
1476 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1477 struct dm_cache_policy *policy,
1478 load_mapping_fn fn, void *context)
1483 r = __load_mappings(cmd, policy, fn, context);
1489 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1496 memcpy(&value, leaf, sizeof(value));
1497 unpack_value(value, &oblock, &flags);
1502 static int __dump_mappings(struct dm_cache_metadata *cmd)
1504 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1507 void dm_cache_dump(struct dm_cache_metadata *cmd)
1509 READ_LOCK_VOID(cmd);
1510 __dump_mappings(cmd);
1514 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1525 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1532 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1536 unpack_value(value, &oblock, &flags);
1538 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1539 /* nothing to be done */
1542 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1543 __dm_bless_for_disk(&value);
1545 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1546 &value, &cmd->root);
1550 cmd->changed = true;
1555 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1559 for (i = 0; i < nr_bits; i++) {
1560 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1568 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1570 unsigned long *bits = context;
1571 *value = test_bit(index, bits);
1575 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1579 /* nr_bits is really just a sanity check */
1580 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1581 DMERR("dirty bitset is wrong size");
1585 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1589 cmd->changed = true;
1590 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1593 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1595 unsigned long *bits)
1600 if (separate_dirty_bits(cmd))
1601 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1603 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1609 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1610 struct dm_cache_statistics *stats)
1612 READ_LOCK_VOID(cmd);
1613 *stats = cmd->stats;
1617 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1618 struct dm_cache_statistics *stats)
1620 WRITE_LOCK_VOID(cmd);
1621 cmd->stats = *stats;
1625 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1628 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1629 clear_clean_shutdown);
1632 r = __commit_transaction(cmd, mutator);
1636 r = __begin_transaction(cmd);
1643 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1649 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1655 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1661 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1667 /*----------------------------------------------------------------*/
1669 static int get_hint(uint32_t index, void *value_le, void *context)
1672 struct dm_cache_policy *policy = context;
1674 value = policy_get_hint(policy, to_cblock(index));
1675 *((__le32 *) value_le) = cpu_to_le32(value);
1681 * It's quicker to always delete the hint array, and recreate with
1684 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1688 const char *policy_name = dm_cache_policy_get_name(policy);
1689 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1691 if (!policy_name[0] ||
1692 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1695 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1696 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1698 hint_size = dm_cache_policy_get_hint_size(policy);
1700 return 0; /* short-circuit hints initialization */
1701 cmd->policy_hint_size = hint_size;
1703 if (cmd->hint_root) {
1704 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1709 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1710 from_cblock(cmd->cache_blocks),
1714 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1719 r = write_hints(cmd, policy);
1725 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1730 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1736 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1738 WRITE_LOCK_VOID(cmd);
1739 dm_bm_set_read_only(cmd->bm);
1743 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1745 WRITE_LOCK_VOID(cmd);
1746 dm_bm_set_read_write(cmd->bm);
1750 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1753 struct dm_block *sblock;
1754 struct cache_disk_superblock *disk_super;
1757 set_bit(NEEDS_CHECK, &cmd->flags);
1759 r = superblock_lock(cmd, &sblock);
1761 DMERR("couldn't read superblock");
1765 disk_super = dm_block_data(sblock);
1766 disk_super->flags = cpu_to_le32(cmd->flags);
1768 dm_bm_unlock(sblock);
1775 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1778 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1784 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1789 __destroy_persistent_data_objects(cmd);
1790 r = __create_persistent_data_objects(cmd, false);
1792 cmd->fail_io = true;