1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2011 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8#ifndef DM_SPACE_MAP_METADATA_H
9#define DM_SPACE_MAP_METADATA_H
10
11#include "dm-transaction-manager.h"
12
13#define DM_SM_METADATA_BLOCK_SIZE (4096 >> SECTOR_SHIFT)
14
15/*
16 * The metadata device is currently limited in size.
17 *
18 * We have one block of index, which can hold 255 index entries. Each
19 * index entry contains allocation info about ~16k metadata blocks.
20 */
21#define DM_SM_METADATA_MAX_BLOCKS (255 * ((1 << 14) - 64))
22#define DM_SM_METADATA_MAX_SECTORS (DM_SM_METADATA_MAX_BLOCKS * DM_SM_METADATA_BLOCK_SIZE)
23
24/*
25 * Unfortunately we have to use two-phase construction due to the cycle
26 * between the tm and sm.
27 */
28struct dm_space_map *dm_sm_metadata_init(void);
29
30/*
31 * Create a fresh space map.
32 */
33int dm_sm_metadata_create(struct dm_space_map *sm,
34 struct dm_transaction_manager *tm,
35 dm_block_t nr_blocks,
36 dm_block_t superblock);
37
38/*
39 * Open from a previously-recorded root.
40 */
41int dm_sm_metadata_open(struct dm_space_map *sm,
42 struct dm_transaction_manager *tm,
43 void *root_le, size_t len);
44
45#endif /* DM_SPACE_MAP_METADATA_H */
46

source code of linux/drivers/md/persistent-data/dm-space-map-metadata.h