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#include "persistent-data/dm-space-map-metadata.h" 13 14#define THIN_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE 15 16/* 17 * The metadata device is currently limited in size. 18 */ 19#define THIN_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS 20 21/* 22 * A metadata device larger than 16GB triggers a warning. 23 */ 24#define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) 25 26/*----------------------------------------------------------------*/ 27 28/* 29 * Thin metadata superblock flags. 30 */ 31#define THIN_METADATA_NEEDS_CHECK_FLAG (1 << 0) 32 33struct dm_pool_metadata; 34struct dm_thin_device; 35 36/* 37 * Device identifier 38 */ 39typedef uint64_t dm_thin_id; 40 41/* 42 * Reopens or creates a new, empty metadata volume. 43 */ 44struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, 45 sector_t data_block_size, 46 bool format_device); 47 48int dm_pool_metadata_close(struct dm_pool_metadata *pmd); 49 50/* 51 * Compat feature flags. Any incompat flags beyond the ones 52 * specified below will prevent use of the thin metadata. 53 */ 54#define THIN_FEATURE_COMPAT_SUPP 0UL 55#define THIN_FEATURE_COMPAT_RO_SUPP 0UL 56#define THIN_FEATURE_INCOMPAT_SUPP 0UL 57 58/* 59 * Device creation/deletion. 60 */ 61int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev); 62 63/* 64 * An internal snapshot. 65 * 66 * You can only snapshot a quiesced origin i.e. one that is either 67 * suspended or not instanced at all. 68 */ 69int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev, 70 dm_thin_id origin); 71 72/* 73 * Deletes a virtual device from the metadata. It _is_ safe to call this 74 * when that device is open. Operations on that device will just start 75 * failing. You still need to call close() on the device. 76 */ 77int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, 78 dm_thin_id dev); 79 80/* 81 * Commits _all_ metadata changes: device creation, deletion, mapping 82 * updates. 83 */ 84int dm_pool_commit_metadata(struct dm_pool_metadata *pmd); 85 86/* 87 * Discards all uncommitted changes. Rereads the superblock, rolling back 88 * to the last good transaction. Thin devices remain open. 89 * dm_thin_aborted_changes() tells you if they had uncommitted changes. 90 * 91 * If this call fails it's only useful to call dm_pool_metadata_close(). 92 * All other methods will fail with -EINVAL. 93 */ 94int dm_pool_abort_metadata(struct dm_pool_metadata *pmd); 95 96/* 97 * Set/get userspace transaction id. 98 */ 99int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, 100 uint64_t current_id, 101 uint64_t new_id); 102 103int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, 104 uint64_t *result); 105 106/* 107 * Hold/get root for userspace transaction. 108 * 109 * The metadata snapshot is a copy of the current superblock (minus the 110 * space maps). Userland can access the data structures for READ 111 * operations only. A small performance hit is incurred by providing this 112 * copy of the metadata to userland due to extra copy-on-write operations 113 * on the metadata nodes. Release this as soon as you finish with it. 114 */ 115int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd); 116int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd); 117 118int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd, 119 dm_block_t *result); 120 121/* 122 * Actions on a single virtual device. 123 */ 124 125/* 126 * Opening the same device more than once will fail with -EBUSY. 127 */ 128int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, 129 struct dm_thin_device **td); 130 131int dm_pool_close_thin_device(struct dm_thin_device *td); 132 133dm_thin_id dm_thin_dev_id(struct dm_thin_device *td); 134 135struct dm_thin_lookup_result { 136 dm_block_t block; 137 bool shared:1; 138}; 139 140/* 141 * Returns: 142 * -EWOULDBLOCK iff @can_issue_io is set and would issue IO 143 * -ENODATA iff that mapping is not present. 144 * 0 success 145 */ 146int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 147 int can_issue_io, struct dm_thin_lookup_result *result); 148 149/* 150 * Obtain an unused block. 151 */ 152int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result); 153 154/* 155 * Insert or remove block. 156 */ 157int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, 158 dm_block_t data_block); 159 160int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); 161 162/* 163 * Queries. 164 */ 165bool dm_thin_changed_this_transaction(struct dm_thin_device *td); 166 167bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd); 168 169bool dm_thin_aborted_changes(struct dm_thin_device *td); 170 171int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, 172 dm_block_t *highest_mapped); 173 174int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result); 175 176int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, 177 dm_block_t *result); 178 179int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, 180 dm_block_t *result); 181 182int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, 183 dm_block_t *result); 184 185int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); 186 187int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result); 188 189/* 190 * Returns -ENOSPC if the new size is too small and already allocated 191 * blocks would be lost. 192 */ 193int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); 194int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); 195 196/* 197 * Flicks the underlying block manager into read only mode, so you know 198 * that nothing is changing. 199 */ 200void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd); 201void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd); 202 203int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, 204 dm_block_t threshold, 205 dm_sm_threshold_fn fn, 206 void *context); 207 208/* 209 * Updates the superblock immediately. 210 */ 211int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd); 212bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd); 213 214/* 215 * Issue any prefetches that may be useful. 216 */ 217void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd); 218 219/*----------------------------------------------------------------*/ 220 221#endif 222