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
 29struct dm_pool_metadata;
 30struct dm_thin_device;
 31
 32/*
 33 * Device identifier
 34 */
 35typedef uint64_t dm_thin_id;
 36
 37/*
 38 * Reopens or creates a new, empty metadata volume.
 39 */
 40struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
 41					       sector_t data_block_size);
 42
 43int 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 */
 56int 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 */
 64int 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 */
 72int 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 */
 79int dm_pool_commit_metadata(struct dm_pool_metadata *pmd);
 80
 81/*
 82 * Set/get userspace transaction id.
 83 */
 84int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
 85					uint64_t current_id,
 86					uint64_t new_id);
 87
 88int 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 */
100int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd);
101int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd);
102
103int 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 */
113int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
114			     struct dm_thin_device **td);
115
116int dm_pool_close_thin_device(struct dm_thin_device *td);
117
118dm_thin_id dm_thin_dev_id(struct dm_thin_device *td);
119
120struct 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 */
131int 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 */
137int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result);
138
139/*
140 * Insert or remove block.
141 */
142int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
143			 dm_block_t data_block);
144
145int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block);
146
147/*
148 * Queries.
149 */
150int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
151				     dm_block_t *highest_mapped);
152
153int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result);
154
155int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd,
156				 dm_block_t *result);
157
158int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
159					  dm_block_t *result);
160
161int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
162				  dm_block_t *result);
163
164int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result);
165
166int 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 */
172int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
173
174/*----------------------------------------------------------------*/
175
176#endif