2 * Copyright (C) 2012 Red Hat, Inc.
4 * This file is released under the GPL.
7 #ifndef DM_CACHE_METADATA_H
8 #define DM_CACHE_METADATA_H
10 #include "dm-cache-block-types.h"
11 #include "dm-cache-policy-internal.h"
12 #include "persistent-data/dm-space-map-metadata.h"
14 /*----------------------------------------------------------------*/
16 #define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
18 /* FIXME: remove this restriction */
20 * The metadata device is currently limited in size.
22 #define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
25 * A metadata device larger than 16GB triggers a warning.
27 #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
29 /*----------------------------------------------------------------*/
32 * Ext[234]-style compat feature flags.
34 * A new feature which old metadata will still be compatible with should
35 * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
37 * A new feature that is not compatible with old code should define a
38 * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
41 * A new feature that is not compatible with old code accessing the
42 * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
43 * guard the relevant code with that flag.
45 * As these various flags are defined they should be added to the
49 #define DM_CACHE_FEATURE_COMPAT_SUPP 0UL
50 #define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL
51 #define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL
54 * Reopens or creates a new, empty metadata volume. Returns an ERR_PTR on
55 * failure. If reopening then features must match.
57 struct dm_cache_metadata
*dm_cache_metadata_open(struct block_device
*bdev
,
58 sector_t data_block_size
,
59 bool may_format_device
,
60 size_t policy_hint_size
,
61 unsigned metadata_version
);
63 void dm_cache_metadata_close(struct dm_cache_metadata
*cmd
);
66 * The metadata needs to know how many cache blocks there are. We don't
67 * care about the origin, assuming the core target is giving us valid
68 * origin blocks to map to.
70 int dm_cache_resize(struct dm_cache_metadata
*cmd
, dm_cblock_t new_cache_size
);
71 int dm_cache_size(struct dm_cache_metadata
*cmd
, dm_cblock_t
*result
);
73 int dm_cache_discard_bitset_resize(struct dm_cache_metadata
*cmd
,
74 sector_t discard_block_size
,
75 dm_dblock_t new_nr_entries
);
77 typedef int (*load_discard_fn
)(void *context
, sector_t discard_block_size
,
78 dm_dblock_t dblock
, bool discarded
);
79 int dm_cache_load_discards(struct dm_cache_metadata
*cmd
,
80 load_discard_fn fn
, void *context
);
82 int dm_cache_set_discard(struct dm_cache_metadata
*cmd
, dm_dblock_t dblock
, bool discard
);
84 int dm_cache_remove_mapping(struct dm_cache_metadata
*cmd
, dm_cblock_t cblock
);
85 int dm_cache_insert_mapping(struct dm_cache_metadata
*cmd
, dm_cblock_t cblock
, dm_oblock_t oblock
);
86 int dm_cache_changed_this_transaction(struct dm_cache_metadata
*cmd
);
88 typedef int (*load_mapping_fn
)(void *context
, dm_oblock_t oblock
,
89 dm_cblock_t cblock
, bool dirty
,
90 uint32_t hint
, bool hint_valid
);
91 int dm_cache_load_mappings(struct dm_cache_metadata
*cmd
,
92 struct dm_cache_policy
*policy
,
96 int dm_cache_set_dirty_bits(struct dm_cache_metadata
*cmd
,
97 unsigned nr_bits
, unsigned long *bits
);
99 struct dm_cache_statistics
{
101 uint32_t read_misses
;
103 uint32_t write_misses
;
106 void dm_cache_metadata_get_stats(struct dm_cache_metadata
*cmd
,
107 struct dm_cache_statistics
*stats
);
110 * 'void' because it's no big deal if it fails.
112 void dm_cache_metadata_set_stats(struct dm_cache_metadata
*cmd
,
113 struct dm_cache_statistics
*stats
);
115 int dm_cache_commit(struct dm_cache_metadata
*cmd
, bool clean_shutdown
);
117 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata
*cmd
,
120 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata
*cmd
,
123 void dm_cache_dump(struct dm_cache_metadata
*cmd
);
126 * The policy is invited to save a 32bit hint value for every cblock (eg,
127 * for a hit count). These are stored against the policy name. If
128 * policies are changed, then hints will be lost. If the machine crashes,
129 * hints will be lost.
131 * The hints are indexed by the cblock, but many policies will not
132 * neccessarily have a fast way of accessing efficiently via cblock. So
133 * rather than querying the policy for each cblock, we let it walk its data
134 * structures and fill in the hints in whatever order it wishes.
136 int dm_cache_write_hints(struct dm_cache_metadata
*cmd
, struct dm_cache_policy
*p
);
139 * Query method. Are all the blocks in the cache clean?
141 int dm_cache_metadata_all_clean(struct dm_cache_metadata
*cmd
, bool *result
);
143 int dm_cache_metadata_needs_check(struct dm_cache_metadata
*cmd
, bool *result
);
144 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata
*cmd
);
145 void dm_cache_metadata_set_read_only(struct dm_cache_metadata
*cmd
);
146 void dm_cache_metadata_set_read_write(struct dm_cache_metadata
*cmd
);
147 int dm_cache_metadata_abort(struct dm_cache_metadata
*cmd
);
149 /*----------------------------------------------------------------*/
151 #endif /* DM_CACHE_METADATA_H */