drivers/md/dm-thin-metadata.h

   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
  16 struct dm_pool_metadata;
  17 struct dm_thin_device;
  18
  19 /*
  20  * Device identifier
  21  */
  22 typedef uint64_t dm_thin_id;
  23
  24 /*
  25  * Reopens or creates a new, empty metadata volume.
  26  */
  27 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
  28                                                sector_t data_block_size);
  29
  30 int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
  31
  32 /*
  33  * Compat feature flags.  Any incompat flags beyond the ones
  34  * specified below will prevent use of the thin metadata.
  35  */
  36 #define THIN_FEATURE_COMPAT_SUPP          0UL
  37 #define THIN_FEATURE_COMPAT_RO_SUPP       0UL
  38 #define THIN_FEATURE_INCOMPAT_SUPP        0UL
  39
  40 /*
  41  * Device creation/deletion.
  42  */
  43 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev);
  44
  45 /*
  46  * An internal snapshot.
  47  *
  48  * You can only snapshot a quiesced origin i.e. one that is either
  49  * suspended or not instanced at all.
  50  */
  51 int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev,
  52                         dm_thin_id origin);
  53
  54 /*
  55  * Deletes a virtual device from the metadata.  It _is_ safe to call this
  56  * when that device is open.  Operations on that device will just start
  57  * failing.  You still need to call close() on the device.
  58  */
  59 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
  60                                dm_thin_id dev);
  61
  62 /*
  63  * Commits _all_ metadata changes: device creation, deletion, mapping
  64  * updates.
  65  */
  66 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd);
  67
  68 /*
  69  * Set/get userspace transaction id.
  70  */
  71 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
  72                                         uint64_t current_id,
  73                                         uint64_t new_id);
  74
  75 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
  76                                         uint64_t *result);
  77
  78 /*
  79  * Hold/get root for userspace transaction.
  80  */
  81 int dm_pool_hold_metadata_root(struct dm_pool_metadata *pmd);
  82
  83 int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd,
  84                                    dm_block_t *result);
  85
  86 /*
  87  * Actions on a single virtual device.
  88  */
  89
  90 /*
  91  * Opening the same device more than once will fail with -EBUSY.
  92  */
  93 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
  94                              struct dm_thin_device **td);
  95
  96 int dm_pool_close_thin_device(struct dm_thin_device *td);
  97
  98 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td);
  99
 100 struct dm_thin_lookup_result {
 101         dm_block_t block;
 102         int shared;
 103 };
 104
 105 /*
 106  * Returns:
 107  *   -EWOULDBLOCK iff @can_block is set and would block.
 108  *   -ENODATA iff that mapping is not present.
 109  *   0 success
 110  */
 111 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
 112                        int can_block, struct dm_thin_lookup_result *result);
 113
 114 /*
 115  * Obtain an unused block.
 116  */
 117 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result);
 118
 119 /*
 120  * Insert or remove block.
 121  */
 122 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
 123                          dm_block_t data_block);
 124
 125 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block);
 126
 127 /*
 128  * Queries.
 129  */
 130 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
 131                                      dm_block_t *highest_mapped);
 132
 133 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result);
 134
 135 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd,
 136                                  dm_block_t *result);
 137
 138 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
 139                                           dm_block_t *result);
 140
 141 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
 142                                   dm_block_t *result);
 143
 144 int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result);
 145
 146 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result);
 147
 148 /*
 149  * Returns -ENOSPC if the new size is too small and already allocated
 150  * blocks would be lost.
 151  */
 152 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
 153
 154 /*----------------------------------------------------------------*/
 155
 156 #endif