drivers/md/dm-cache-metadata.h

   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
  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 int 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 /*
 126  * The policy is invited to save a 32bit hint value for every cblock (eg,
 127  * for a hit count).  These are stored against the policy name.  If
 128  * policies are changed, then hints will be lost.  If the machine crashes,
 129  * hints will be lost.
 130  *
 131  * The hints are indexed by the cblock, but many policies will not
 132  * necessarily have a fast way of accessing efficiently via cblock.  So
 133  * rather than querying the policy for each cblock, we let it walk its data
 134  * structures and fill in the hints in whatever order it wishes.
 135  */
 136 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);
 137
 138 /*
 139  * Query method.  Are all the blocks in the cache clean?
 140  */
 141 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result);
 142
 143 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result);
 144 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
 145 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
 146 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
 147 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd);
 148
 149 /*----------------------------------------------------------------*/
 150
 151 #endif /* DM_CACHE_METADATA_H */