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c6b4fcba JT |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #ifndef DM_CACHE_METADATA_H | |
8 | #define DM_CACHE_METADATA_H | |
9 | ||
10 | #include "dm-cache-block-types.h" | |
11 | #include "dm-cache-policy-internal.h" | |
12 | ||
13 | /*----------------------------------------------------------------*/ | |
14 | ||
15 | #define DM_CACHE_METADATA_BLOCK_SIZE 4096 | |
16 | ||
17 | /* FIXME: remove this restriction */ | |
18 | /* | |
19 | * The metadata device is currently limited in size. | |
20 | * | |
21 | * We have one block of index, which can hold 255 index entries. Each | |
22 | * index entry contains allocation info about 16k metadata blocks. | |
23 | */ | |
24 | #define DM_CACHE_METADATA_MAX_SECTORS (255 * (1 << 14) * (DM_CACHE_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) | |
25 | ||
26 | /* | |
27 | * A metadata device larger than 16GB triggers a warning. | |
28 | */ | |
29 | #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) | |
30 | ||
31 | /*----------------------------------------------------------------*/ | |
32 | ||
33 | /* | |
34 | * Ext[234]-style compat feature flags. | |
35 | * | |
36 | * A new feature which old metadata will still be compatible with should | |
37 | * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful). | |
38 | * | |
39 | * A new feature that is not compatible with old code should define a | |
40 | * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with | |
41 | * that flag. | |
42 | * | |
43 | * A new feature that is not compatible with old code accessing the | |
44 | * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and | |
45 | * guard the relevant code with that flag. | |
46 | * | |
47 | * As these various flags are defined they should be added to the | |
48 | * following masks. | |
49 | */ | |
50 | #define DM_CACHE_FEATURE_COMPAT_SUPP 0UL | |
51 | #define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL | |
52 | #define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL | |
53 | ||
54 | /* | |
55 | * Reopens or creates a new, empty metadata volume. | |
56 | * Returns an ERR_PTR on failure. | |
57 | */ | |
58 | struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, | |
59 | sector_t data_block_size, | |
60 | bool may_format_device, | |
61 | size_t policy_hint_size); | |
62 | ||
63 | void dm_cache_metadata_close(struct dm_cache_metadata *cmd); | |
64 | ||
65 | /* | |
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. | |
69 | */ | |
70 | int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size); | |
71 | dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd); | |
72 | ||
73 | int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, | |
74 | sector_t discard_block_size, | |
64ab346a | 75 | dm_oblock_t new_nr_entries); |
c6b4fcba JT |
76 | |
77 | typedef int (*load_discard_fn)(void *context, sector_t discard_block_size, | |
64ab346a | 78 | dm_oblock_t dblock, bool discarded); |
c6b4fcba JT |
79 | int dm_cache_load_discards(struct dm_cache_metadata *cmd, |
80 | load_discard_fn fn, void *context); | |
81 | ||
64ab346a | 82 | int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_oblock_t dblock, bool discard); |
c6b4fcba JT |
83 | |
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); | |
87 | ||
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, | |
ea2dd8c1 | 92 | struct dm_cache_policy *policy, |
c6b4fcba JT |
93 | load_mapping_fn fn, |
94 | void *context); | |
95 | ||
96 | int dm_cache_set_dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty); | |
97 | ||
98 | struct dm_cache_statistics { | |
99 | uint32_t read_hits; | |
100 | uint32_t read_misses; | |
101 | uint32_t write_hits; | |
102 | uint32_t write_misses; | |
103 | }; | |
104 | ||
105 | void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, | |
106 | struct dm_cache_statistics *stats); | |
107 | void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, | |
108 | struct dm_cache_statistics *stats); | |
109 | ||
110 | int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown); | |
111 | ||
112 | int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, | |
113 | dm_block_t *result); | |
114 | ||
115 | int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, | |
116 | dm_block_t *result); | |
117 | ||
118 | void dm_cache_dump(struct dm_cache_metadata *cmd); | |
119 | ||
120 | /* | |
121 | * The policy is invited to save a 32bit hint value for every cblock (eg, | |
122 | * for a hit count). These are stored against the policy name. If | |
123 | * policies are changed, then hints will be lost. If the machine crashes, | |
124 | * hints will be lost. | |
125 | * | |
126 | * The hints are indexed by the cblock, but many policies will not | |
127 | * neccessarily have a fast way of accessing efficiently via cblock. So | |
128 | * rather than querying the policy for each cblock, we let it walk its data | |
129 | * structures and fill in the hints in whatever order it wishes. | |
130 | */ | |
0596661f | 131 | int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p); |
c6b4fcba | 132 | |
2ee57d58 JT |
133 | /* |
134 | * Query method. Are all the blocks in the cache clean? | |
135 | */ | |
136 | int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result); | |
137 | ||
c6b4fcba JT |
138 | /*----------------------------------------------------------------*/ |
139 | ||
140 | #endif /* DM_CACHE_METADATA_H */ |