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 #include "persistent-data/dm-space-map-metadata.h" 13 14 /*----------------------------------------------------------------*/ 15 16 #define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE 17 18 /* FIXME: remove this restriction */ 19 /* 20 * The metadata device is currently limited in size. 21 */ 22 #define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS 23 24 /* 25 * A metadata device larger than 16GB triggers a warning. 26 */ 27 #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) 28 29 /*----------------------------------------------------------------*/ 30 31 /* 32 * Ext[234]-style compat feature flags. 33 * 34 * A new feature which old metadata will still be compatible with should 35 * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful). 36 * 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 39 * that flag. 40 * 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. 44 * 45 * As these various flags are defined they should be added to the 46 * following masks. 47 */ 48 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 52 53 struct dm_cache_metadata; 54 55 /* 56 * Reopens or creates a new, empty metadata volume. Returns an ERR_PTR on 57 * failure. If reopening then features must match. 58 */ 59 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 60 sector_t data_block_size, 61 bool may_format_device, 62 size_t policy_hint_size, 63 unsigned metadata_version); 64 65 void dm_cache_metadata_close(struct dm_cache_metadata *cmd); 66 67 /* 68 * The metadata needs to know how many cache blocks there are. We don't 69 * care about the origin, assuming the core target is giving us valid 70 * origin blocks to map to. 71 */ 72 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size); 73 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result); 74 75 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 76 sector_t discard_block_size, 77 dm_dblock_t new_nr_entries); 78 79 typedef int (*load_discard_fn)(void *context, sector_t discard_block_size, 80 dm_dblock_t dblock, bool discarded); 81 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 82 load_discard_fn fn, void *context); 83 84 int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard); 85 86 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock); 87 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock); 88 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd); 89 90 typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock, 91 dm_cblock_t cblock, bool dirty, 92 uint32_t hint, bool hint_valid); 93 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 94 struct dm_cache_policy *policy, 95 load_mapping_fn fn, 96 void *context); 97 98 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, 99 unsigned nr_bits, unsigned long *bits); 100 101 struct dm_cache_statistics { 102 uint32_t read_hits; 103 uint32_t read_misses; 104 uint32_t write_hits; 105 uint32_t write_misses; 106 }; 107 108 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 109 struct dm_cache_statistics *stats); 110 111 /* 112 * 'void' because it's no big deal if it fails. 113 */ 114 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 115 struct dm_cache_statistics *stats); 116 117 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown); 118 119 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 120 dm_block_t *result); 121 122 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 123 dm_block_t *result); 124 125 void dm_cache_dump(struct dm_cache_metadata *cmd); 126 127 /* 128 * The policy is invited to save a 32bit hint value for every cblock (eg, 129 * for a hit count). These are stored against the policy name. If 130 * policies are changed, then hints will be lost. If the machine crashes, 131 * hints will be lost. 132 * 133 * The hints are indexed by the cblock, but many policies will not 134 * necessarily have a fast way of accessing efficiently via cblock. So 135 * rather than querying the policy for each cblock, we let it walk its data 136 * structures and fill in the hints in whatever order it wishes. 137 */ 138 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p); 139 140 /* 141 * Query method. Are all the blocks in the cache clean? 142 */ 143 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result); 144 145 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result); 146 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd); 147 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd); 148 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd); 149 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd); 150 151 /*----------------------------------------------------------------*/ 152 153 #endif /* DM_CACHE_METADATA_H */ 154