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 12 #define THIN_METADATA_BLOCK_SIZE 4096 13 14 /* 15 * The metadata device is currently limited in size. 16 * 17 * We have one block of index, which can hold 255 index entries. Each 18 * index entry contains allocation info about 16k metadata blocks. 19 */ 20 #define THIN_METADATA_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) 21 22 /* 23 * A metadata device larger than 16GB triggers a warning. 24 */ 25 #define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) 26 27 /*----------------------------------------------------------------*/ 28 29 struct dm_pool_metadata; 30 struct dm_thin_device; 31 32 /* 33 * Device identifier 34 */ 35 typedef uint64_t dm_thin_id; 36 37 /* 38 * Reopens or creates a new, empty metadata volume. 39 */ 40 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, 41 sector_t data_block_size); 42 43 int dm_pool_metadata_close(struct dm_pool_metadata *pmd); 44 45 /* 46 * Compat feature flags. Any incompat flags beyond the ones 47 * specified below will prevent use of the thin metadata. 48 */ 49 #define THIN_FEATURE_COMPAT_SUPP 0UL 50 #define THIN_FEATURE_COMPAT_RO_SUPP 0UL 51 #define THIN_FEATURE_INCOMPAT_SUPP 0UL 52 53 /* 54 * Device creation/deletion. 55 */ 56 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev); 57 58 /* 59 * An internal snapshot. 60 * 61 * You can only snapshot a quiesced origin i.e. one that is either 62 * suspended or not instanced at all. 63 */ 64 int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev, 65 dm_thin_id origin); 66 67 /* 68 * Deletes a virtual device from the metadata. It _is_ safe to call this 69 * when that device is open. Operations on that device will just start 70 * failing. You still need to call close() on the device. 71 */ 72 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, 73 dm_thin_id dev); 74 75 /* 76 * Commits _all_ metadata changes: device creation, deletion, mapping 77 * updates. 78 */ 79 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd); 80 81 /* 82 * Set/get userspace transaction id. 83 */ 84 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, 85 uint64_t current_id, 86 uint64_t new_id); 87 88 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, 89 uint64_t *result); 90 91 /* 92 * Hold/get root for userspace transaction. 93 * 94 * The metadata snapshot is a copy of the current superblock (minus the 95 * space maps). Userland can access the data structures for READ 96 * operations only. A small performance hit is incurred by providing this 97 * copy of the metadata to userland due to extra copy-on-write operations 98 * on the metadata nodes. Release this as soon as you finish with it. 99 */ 100 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd); 101 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd); 102 103 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd, 104 dm_block_t *result); 105 106 /* 107 * Actions on a single virtual device. 108 */ 109 110 /* 111 * Opening the same device more than once will fail with -EBUSY. 112 */ 113 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, 114 struct dm_thin_device **td); 115 116 int dm_pool_close_thin_device(struct dm_thin_device *td); 117 118 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td); 119 120 struct dm_thin_lookup_result { 121 dm_block_t block; 122 int shared; 123 }; 124 125 /* 126 * Returns: 127 * -EWOULDBLOCK iff @can_block is set and would block. 128 * -ENODATA iff that mapping is not present. 129 * 0 success 130 */ 131 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 132 int can_block, struct dm_thin_lookup_result *result); 133 134 /* 135 * Obtain an unused block. 136 */ 137 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result); 138 139 /* 140 * Insert or remove block. 141 */ 142 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, 143 dm_block_t data_block); 144 145 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); 146 147 /* 148 * Queries. 149 */ 150 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, 151 dm_block_t *highest_mapped); 152 153 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result); 154 155 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, 156 dm_block_t *result); 157 158 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, 159 dm_block_t *result); 160 161 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, 162 dm_block_t *result); 163 164 int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result); 165 166 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); 167 168 /* 169 * Returns -ENOSPC if the new size is too small and already allocated 170 * blocks would be lost. 171 */ 172 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); 173 174 /*----------------------------------------------------------------*/ 175 176 #endif 177