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 #define DM_CACHE_FEATURE_COMPAT_SUPP 0UL 49 #define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL 50 #define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL 51 52 /* 53 * Reopens or creates a new, empty metadata volume. 54 * Returns an ERR_PTR on failure. 55 */ 56 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 57 sector_t data_block_size, 58 bool may_format_device, 59 size_t policy_hint_size); 60 61 void dm_cache_metadata_close(struct dm_cache_metadata *cmd); 62 63 /* 64 * The metadata needs to know how many cache blocks there are. We don't 65 * care about the origin, assuming the core target is giving us valid 66 * origin blocks to map to. 67 */ 68 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size); 69 dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd); 70 71 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 72 sector_t discard_block_size, 73 dm_oblock_t new_nr_entries); 74 75 typedef int (*load_discard_fn)(void *context, sector_t discard_block_size, 76 dm_oblock_t dblock, bool discarded); 77 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 78 load_discard_fn fn, void *context); 79 80 int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_oblock_t dblock, bool discard); 81 82 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock); 83 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock); 84 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd); 85 86 typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock, 87 dm_cblock_t cblock, bool dirty, 88 uint32_t hint, bool hint_valid); 89 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 90 struct dm_cache_policy *policy, 91 load_mapping_fn fn, 92 void *context); 93 94 int dm_cache_set_dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty); 95 96 struct dm_cache_statistics { 97 uint32_t read_hits; 98 uint32_t read_misses; 99 uint32_t write_hits; 100 uint32_t write_misses; 101 }; 102 103 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 104 struct dm_cache_statistics *stats); 105 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 106 struct dm_cache_statistics *stats); 107 108 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown); 109 110 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 111 dm_block_t *result); 112 113 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 114 dm_block_t *result); 115 116 void dm_cache_dump(struct dm_cache_metadata *cmd); 117 118 /* 119 * The policy is invited to save a 32bit hint value for every cblock (eg, 120 * for a hit count). These are stored against the policy name. If 121 * policies are changed, then hints will be lost. If the machine crashes, 122 * hints will be lost. 123 * 124 * The hints are indexed by the cblock, but many policies will not 125 * neccessarily have a fast way of accessing efficiently via cblock. So 126 * rather than querying the policy for each cblock, we let it walk its data 127 * structures and fill in the hints in whatever order it wishes. 128 */ 129 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p); 130 131 /* 132 * Query method. Are all the blocks in the cache clean? 133 */ 134 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result); 135 136 /*----------------------------------------------------------------*/ 137 138 #endif /* DM_CACHE_METADATA_H */ 139