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