1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.
6 #ifndef DM_CLONE_METADATA_H
7 #define DM_CLONE_METADATA_H
9 #include "persistent-data/dm-block-manager.h"
10 #include "persistent-data/dm-space-map-metadata.h"
12 #define DM_CLONE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
15 * The metadata device is currently limited in size.
17 #define DM_CLONE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
20 * A metadata device larger than 16GB triggers a warning.
22 #define DM_CLONE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
24 #define SPACE_MAP_ROOT_SIZE 128
26 /* dm-clone metadata */
27 struct dm_clone_metadata;
30 * Set region status to hydrated.
32 * @cmd: The dm-clone metadata
33 * @region_nr: The region number
35 * This function doesn't block, so it's safe to call it from interrupt context.
37 int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);
40 * Set status of all regions in the provided range to hydrated, if not already
43 * @cmd: The dm-clone metadata
44 * @start: Starting region number
45 * @nr_regions: Number of regions in the range
47 * This function doesn't block, but since it uses spin_lock_irq()/spin_unlock_irq()
48 * it's NOT safe to call it from any context where interrupts are disabled, e.g.,
49 * from interrupt context.
51 int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,
52 unsigned long nr_regions);
55 * Read existing or create fresh metadata.
57 * @bdev: The device storing the metadata
58 * @target_size: The target size
59 * @region_size: The region size
61 * @returns: The dm-clone metadata
63 * This function reads the superblock of @bdev and checks if it's all zeroes.
64 * If it is, it formats @bdev and creates fresh metadata. If it isn't, it
65 * validates the metadata stored in @bdev.
67 struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev,
69 sector_t region_size);
72 * Free the resources related to metadata management.
74 void dm_clone_metadata_close(struct dm_clone_metadata *cmd);
77 * Commit dm-clone metadata to disk.
79 int dm_clone_metadata_commit(struct dm_clone_metadata *cmd);
82 * Reload the in core copy of the on-disk bitmap.
84 * This should be used after aborting a metadata transaction and setting the
85 * metadata to read-only, to invalidate the in-core cache and make it match the
88 * WARNING: It must not be called concurrently with either
89 * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it updates
90 * the region bitmap without taking the relevant spinlock. We don't take the
91 * spinlock because dm_clone_reload_in_core_bitset() does I/O, so it may block.
93 * But, it's safe to use it after calling dm_clone_metadata_set_read_only(),
94 * because the latter sets the metadata to read-only mode. Both
95 * dm_clone_set_region_hydrated() and dm_clone_cond_set_range() refuse to touch
96 * the region bitmap, after calling dm_clone_metadata_set_read_only().
98 int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd);
101 * Check whether dm-clone's metadata changed this transaction.
103 bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd);
106 * Abort current metadata transaction and rollback metadata to the last
107 * committed transaction.
109 int dm_clone_metadata_abort(struct dm_clone_metadata *cmd);
112 * Switches metadata to a read only mode. Once read-only mode has been entered
113 * the following functions will return -EPERM:
115 * dm_clone_metadata_commit()
116 * dm_clone_set_region_hydrated()
117 * dm_clone_cond_set_range()
118 * dm_clone_metadata_abort()
120 void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd);
121 void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd);
124 * Returns true if the hydration of the destination device is finished.
126 bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd);
129 * Returns true if region @region_nr is hydrated.
131 bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);
134 * Returns true if all the regions in the range are hydrated.
136 bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd,
137 unsigned long start, unsigned long nr_regions);
140 * Returns the number of hydrated regions.
142 unsigned long dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd);
145 * Returns the first unhydrated region with region_nr >= @start
147 unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd,
148 unsigned long start);
151 * Get the number of free metadata blocks.
153 int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, dm_block_t *result);
156 * Get the total number of metadata blocks.
158 int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, dm_block_t *result);
160 #endif /* DM_CLONE_METADATA_H */