1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * Copyright (C) 2012 Red Hat, Inc. |
4 | * |
5 | * This file is released under the GPL. |
6 | */ |
7 | |
8 | #ifndef DM_CACHE_METADATA_H |
9 | #define DM_CACHE_METADATA_H |
10 | |
11 | #include "dm-cache-block-types.h" |
12 | #include "dm-cache-policy-internal.h" |
13 | #include "persistent-data/dm-space-map-metadata.h" |
14 | |
15 | /*----------------------------------------------------------------*/ |
16 | |
17 | #define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE |
18 | |
19 | /* FIXME: remove this restriction */ |
20 | /* |
21 | * The metadata device is currently limited in size. |
22 | */ |
23 | #define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS |
24 | |
25 | /* |
26 | * A metadata device larger than 16GB triggers a warning. |
27 | */ |
28 | #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) |
29 | |
30 | /*----------------------------------------------------------------*/ |
31 | |
32 | /* |
33 | * Ext[234]-style compat feature flags. |
34 | * |
35 | * A new feature which old metadata will still be compatible with should |
36 | * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful). |
37 | * |
38 | * A new feature that is not compatible with old code should define a |
39 | * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with |
40 | * that flag. |
41 | * |
42 | * A new feature that is not compatible with old code accessing the |
43 | * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and |
44 | * guard the relevant code with that flag. |
45 | * |
46 | * As these various flags are defined they should be added to the |
47 | * following masks. |
48 | */ |
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 | struct dm_cache_metadata; |
55 | |
56 | /* |
57 | * Reopens or creates a new, empty metadata volume. Returns an ERR_PTR on |
58 | * failure. If reopening then features must match. |
59 | */ |
60 | struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, |
61 | sector_t data_block_size, |
62 | bool may_format_device, |
63 | size_t policy_hint_size, |
64 | unsigned int metadata_version); |
65 | |
66 | void dm_cache_metadata_close(struct dm_cache_metadata *cmd); |
67 | |
68 | /* |
69 | * The metadata needs to know how many cache blocks there are. We don't |
70 | * care about the origin, assuming the core target is giving us valid |
71 | * origin blocks to map to. |
72 | */ |
73 | int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size); |
74 | int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result); |
75 | |
76 | int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, |
77 | sector_t discard_block_size, |
78 | dm_dblock_t new_nr_entries); |
79 | |
80 | typedef int (*load_discard_fn)(void *context, sector_t discard_block_size, |
81 | dm_dblock_t dblock, bool discarded); |
82 | int dm_cache_load_discards(struct dm_cache_metadata *cmd, |
83 | load_discard_fn fn, void *context); |
84 | |
85 | int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard); |
86 | |
87 | int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock); |
88 | int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock); |
89 | int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd); |
90 | |
91 | typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock, |
92 | dm_cblock_t cblock, bool dirty, |
93 | uint32_t hint, bool hint_valid); |
94 | int dm_cache_load_mappings(struct dm_cache_metadata *cmd, |
95 | struct dm_cache_policy *policy, |
96 | load_mapping_fn fn, |
97 | void *context); |
98 | |
99 | int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, |
100 | unsigned int nr_bits, unsigned long *bits); |
101 | |
102 | struct dm_cache_statistics { |
103 | uint32_t read_hits; |
104 | uint32_t read_misses; |
105 | uint32_t write_hits; |
106 | uint32_t write_misses; |
107 | }; |
108 | |
109 | void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, |
110 | struct dm_cache_statistics *stats); |
111 | |
112 | /* |
113 | * 'void' because it's no big deal if it fails. |
114 | */ |
115 | void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, |
116 | struct dm_cache_statistics *stats); |
117 | |
118 | int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown); |
119 | |
120 | int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, |
121 | dm_block_t *result); |
122 | |
123 | int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, |
124 | dm_block_t *result); |
125 | |
126 | void dm_cache_dump(struct dm_cache_metadata *cmd); |
127 | |
128 | /* |
129 | * The policy is invited to save a 32bit hint value for every cblock (eg, |
130 | * for a hit count). These are stored against the policy name. If |
131 | * policies are changed, then hints will be lost. If the machine crashes, |
132 | * hints will be lost. |
133 | * |
134 | * The hints are indexed by the cblock, but many policies will not |
135 | * necessarily have a fast way of accessing efficiently via cblock. So |
136 | * rather than querying the policy for each cblock, we let it walk its data |
137 | * structures and fill in the hints in whatever order it wishes. |
138 | */ |
139 | int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p); |
140 | |
141 | /* |
142 | * Query method. Are all the blocks in the cache clean? |
143 | */ |
144 | int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result); |
145 | |
146 | int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result); |
147 | int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd); |
148 | void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd); |
149 | void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd); |
150 | int dm_cache_metadata_abort(struct dm_cache_metadata *cmd); |
151 | |
152 | /*----------------------------------------------------------------*/ |
153 | |
154 | #endif /* DM_CACHE_METADATA_H */ |
155 | |