drivers/md/dm-thin-metadata.h

   1 /*
   2  * Copyright (C) 2010-2011 Red Hat, Inc. All rights reserved.
   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 /*----------------------------------------------------------------*/
  13
  14 struct dm_pool_metadata;
  15 struct dm_thin_device;
  16
  17 /*
  18  * Device identifier
  19  */
  20 typedef uint64_t dm_thin_id;
  21
  22 /*
  23  * Reopens or creates a new, empty metadata volume.
  24  */
  25 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
  26                                                sector_t data_block_size);
  27
  28 int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
  29
  30 /*
  31  * This does not currently resize the metadata device, but should eventually.
  32  */
  33 int dm_pool_rebind_metadata_device(struct dm_pool_metadata *pmd,
  34                                    struct block_device *bdev);
  35
  36 /*
  37  * Compat feature flags.  Any incompat flags beyond the ones
  38  * specified below will prevent use of the thin metadata.
  39  */
  40 #define THIN_FEATURE_COMPAT_SUPP          0UL
  41 #define THIN_FEATURE_COMPAT_RO_SUPP       0UL
  42 #define THIN_FEATURE_INCOMPAT_SUPP        0UL
  43
  44 /*
  45  * Device creation/deletion.
  46  */
  47 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev);
  48
  49 /*
  50  * An internal snapshot.
  51  *
  52  * You can only snapshot a quiesced origin i.e. one that is either
  53  * suspended or not instanced at all.
  54  */
  55 int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev,
  56                         dm_thin_id origin);
  57
  58 /*
  59  * Deletes a virtual device from the metadata.  It _is_ safe to call this
  60  * when that device is open.  Operations on that device will just start
  61  * failing.  You still need to call close() on the device.
  62  */
  63 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
  64                                dm_thin_id dev);
  65
  66 /*
  67  * Thin devices don't have a size, however they do keep track of the
  68  * highest mapped block.  This trimming function allows the user to remove
  69  * mappings above a certain virtual block.
  70  */
  71 int dm_pool_trim_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
  72                              sector_t new_size);
  73
  74 /*
  75  * Commits _all_ metadata changes: device creation, deletion, mapping
  76  * updates.
  77  */
  78 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd);
  79
  80 /*
  81  * Set/get userspace transaction id.
  82  */
  83 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
  84                                         uint64_t current_id,
  85                                         uint64_t new_id);
  86
  87 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
  88                                         uint64_t *result);
  89
  90 /*
  91  * Hold/get root for userspace transaction.
  92  */
  93 int dm_pool_hold_metadata_root(struct dm_pool_metadata *pmd);
  94
  95 int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd,
  96                                    dm_block_t *result);
  97
  98 /*
  99  * Actions on a single virtual device.
 100  */
 101
 102 /*
 103  * Opening the same device more than once will fail with -EBUSY.
 104  */
 105 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
 106                              struct dm_thin_device **td);
 107
 108 int dm_pool_close_thin_device(struct dm_thin_device *td);
 109
 110 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td);
 111
 112 struct dm_thin_lookup_result {
 113         dm_block_t block;
 114         int shared;
 115 };
 116
 117 /*
 118  * Returns:
 119  *   -EWOULDBLOCK iff @can_block is set and would block.
 120  *   -ENODATA iff that mapping is not present.
 121  *   0 success
 122  */
 123 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
 124                        int can_block, struct dm_thin_lookup_result *result);
 125
 126 /*
 127  * Obtain an unused block.
 128  */
 129 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result);
 130
 131 /*
 132  * Insert or remove block.
 133  */
 134 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
 135                          dm_block_t data_block);
 136
 137 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block);
 138
 139 /*
 140  * Queries.
 141  */
 142 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
 143                                      dm_block_t *highest_mapped);
 144
 145 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result);
 146
 147 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd,
 148                                  dm_block_t *result);
 149
 150 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
 151                                           dm_block_t *result);
 152
 153 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
 154                                   dm_block_t *result);
 155
 156 int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result);
 157
 158 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result);
 159
 160 /*
 161  * Returns -ENOSPC if the new size is too small and already allocated
 162  * blocks would be lost.
 163  */
 164 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
 165
 166 /*----------------------------------------------------------------*/
 167
 168 #endif