1 /* 2 * Copyright (C) 2010-2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #ifndef DM_THIN_METADATA_H 8 #define DM_THIN_METADATA_H 9 10 #include "persistent-data/dm-block-manager.h" 11 #include "persistent-data/dm-space-map.h" 12 13 #define THIN_METADATA_BLOCK_SIZE 4096 14 15 /* 16 * The metadata device is currently limited in size. 17 * 18 * We have one block of index, which can hold 255 index entries. Each 19 * index entry contains allocation info about 16k metadata blocks. 20 */ 21 #define THIN_METADATA_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) 22 23 /* 24 * A metadata device larger than 16GB triggers a warning. 25 */ 26 #define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) 27 28 /*----------------------------------------------------------------*/ 29 30 struct dm_pool_metadata; 31 struct dm_thin_device; 32 33 /* 34 * Device identifier 35 */ 36 typedef uint64_t dm_thin_id; 37 38 /* 39 * Reopens or creates a new, empty metadata volume. 40 */ 41 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, 42 sector_t data_block_size, 43 bool format_device); 44 45 int dm_pool_metadata_close(struct dm_pool_metadata *pmd); 46 47 /* 48 * Compat feature flags. Any incompat flags beyond the ones 49 * specified below will prevent use of the thin metadata. 50 */ 51 #define THIN_FEATURE_COMPAT_SUPP 0UL 52 #define THIN_FEATURE_COMPAT_RO_SUPP 0UL 53 #define THIN_FEATURE_INCOMPAT_SUPP 0UL 54 55 /* 56 * Device creation/deletion. 57 */ 58 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev); 59 60 /* 61 * An internal snapshot. 62 * 63 * You can only snapshot a quiesced origin i.e. one that is either 64 * suspended or not instanced at all. 65 */ 66 int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev, 67 dm_thin_id origin); 68 69 /* 70 * Deletes a virtual device from the metadata. It _is_ safe to call this 71 * when that device is open. Operations on that device will just start 72 * failing. You still need to call close() on the device. 73 */ 74 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, 75 dm_thin_id dev); 76 77 /* 78 * Commits _all_ metadata changes: device creation, deletion, mapping 79 * updates. 80 */ 81 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd); 82 83 /* 84 * Discards all uncommitted changes. Rereads the superblock, rolling back 85 * to the last good transaction. Thin devices remain open. 86 * dm_thin_aborted_changes() tells you if they had uncommitted changes. 87 * 88 * If this call fails it's only useful to call dm_pool_metadata_close(). 89 * All other methods will fail with -EINVAL. 90 */ 91 int dm_pool_abort_metadata(struct dm_pool_metadata *pmd); 92 93 /* 94 * Set/get userspace transaction id. 95 */ 96 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, 97 uint64_t current_id, 98 uint64_t new_id); 99 100 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, 101 uint64_t *result); 102 103 /* 104 * Hold/get root for userspace transaction. 105 * 106 * The metadata snapshot is a copy of the current superblock (minus the 107 * space maps). Userland can access the data structures for READ 108 * operations only. A small performance hit is incurred by providing this 109 * copy of the metadata to userland due to extra copy-on-write operations 110 * on the metadata nodes. Release this as soon as you finish with it. 111 */ 112 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd); 113 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd); 114 115 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd, 116 dm_block_t *result); 117 118 /* 119 * Actions on a single virtual device. 120 */ 121 122 /* 123 * Opening the same device more than once will fail with -EBUSY. 124 */ 125 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, 126 struct dm_thin_device **td); 127 128 int dm_pool_close_thin_device(struct dm_thin_device *td); 129 130 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td); 131 132 struct dm_thin_lookup_result { 133 dm_block_t block; 134 unsigned shared:1; 135 }; 136 137 /* 138 * Returns: 139 * -EWOULDBLOCK iff @can_block is set and would block. 140 * -ENODATA iff that mapping is not present. 141 * 0 success 142 */ 143 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 144 int can_block, struct dm_thin_lookup_result *result); 145 146 /* 147 * Obtain an unused block. 148 */ 149 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result); 150 151 /* 152 * Insert or remove block. 153 */ 154 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, 155 dm_block_t data_block); 156 157 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); 158 159 /* 160 * Queries. 161 */ 162 bool dm_thin_changed_this_transaction(struct dm_thin_device *td); 163 164 bool dm_thin_aborted_changes(struct dm_thin_device *td); 165 166 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, 167 dm_block_t *highest_mapped); 168 169 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result); 170 171 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, 172 dm_block_t *result); 173 174 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, 175 dm_block_t *result); 176 177 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, 178 dm_block_t *result); 179 180 int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result); 181 182 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); 183 184 /* 185 * Returns -ENOSPC if the new size is too small and already allocated 186 * blocks would be lost. 187 */ 188 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); 189 int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); 190 191 /* 192 * Flicks the underlying block manager into read only mode, so you know 193 * that nothing is changing. 194 */ 195 void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd); 196 197 int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, 198 dm_block_t threshold, 199 dm_sm_threshold_fn fn, 200 void *context); 201 202 /*----------------------------------------------------------------*/ 203 204 #endif 205