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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - drivers/md/dm-thin-metadata.h
2 * Copyright (C) 2010-2011 Red Hat, Inc.
4 * This file is released under the GPL.
7 #ifndef DM_THIN_METADATA_H
8 #define DM_THIN_METADATA_H
10 #include "persistent-data/dm-block-manager.h"
11 #include "persistent-data/dm-space-map.h"
13 #define THIN_METADATA_BLOCK_SIZE 4096
16 * The metadata device is currently limited in size.
18 * We have one block of index, which can hold 255 index entries. Each
19 * index entry contains allocation info about 16k metadata blocks.
21 #define THIN_METADATA_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
24 * A metadata device larger than 16GB triggers a warning.
26 #define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
28 /*----------------------------------------------------------------*/
30 struct dm_pool_metadata
;
31 struct dm_thin_device
;
36 typedef uint64_t dm_thin_id
;
39 * Reopens or creates a new, empty metadata volume.
41 struct dm_pool_metadata
*dm_pool_metadata_open(struct block_device
*bdev
,
42 sector_t data_block_size
,
45 int dm_pool_metadata_close(struct dm_pool_metadata
*pmd
);
48 * Compat feature flags. Any incompat flags beyond the ones
49 * specified below will prevent use of the thin metadata.
51 #define THIN_FEATURE_COMPAT_SUPP 0UL
52 #define THIN_FEATURE_COMPAT_RO_SUPP 0UL
53 #define THIN_FEATURE_INCOMPAT_SUPP 0UL
56 * Device creation/deletion.
58 int dm_pool_create_thin(struct dm_pool_metadata
*pmd
, dm_thin_id dev
);
61 * An internal snapshot.
63 * You can only snapshot a quiesced origin i.e. one that is either
64 * suspended or not instanced at all.
66 int dm_pool_create_snap(struct dm_pool_metadata
*pmd
, dm_thin_id dev
,
70 * Deletes a virtual device from the metadata. It _is_ safe to call this
71 * when that device is open. Operations on that device will just start
72 * failing. You still need to call close() on the device.
74 int dm_pool_delete_thin_device(struct dm_pool_metadata
*pmd
,
78 * Commits _all_ metadata changes: device creation, deletion, mapping
81 int dm_pool_commit_metadata(struct dm_pool_metadata
*pmd
);
84 * Discards all uncommitted changes. Rereads the superblock, rolling back
85 * to the last good transaction. Thin devices remain open.
86 * dm_thin_aborted_changes() tells you if they had uncommitted changes.
88 * If this call fails it's only useful to call dm_pool_metadata_close().
89 * All other methods will fail with -EINVAL.
91 int dm_pool_abort_metadata(struct dm_pool_metadata
*pmd
);
94 * Set/get userspace transaction id.
96 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata
*pmd
,
100 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata
*pmd
,
104 * Hold/get root for userspace transaction.
106 * The metadata snapshot is a copy of the current superblock (minus the
107 * space maps). Userland can access the data structures for READ
108 * operations only. A small performance hit is incurred by providing this
109 * copy of the metadata to userland due to extra copy-on-write operations
110 * on the metadata nodes. Release this as soon as you finish with it.
112 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata
*pmd
);
113 int dm_pool_release_metadata_snap(struct dm_pool_metadata
*pmd
);
115 int dm_pool_get_metadata_snap(struct dm_pool_metadata
*pmd
,
119 * Actions on a single virtual device.
123 * Opening the same device more than once will fail with -EBUSY.
125 int dm_pool_open_thin_device(struct dm_pool_metadata
*pmd
, dm_thin_id dev
,
126 struct dm_thin_device
**td
);
128 int dm_pool_close_thin_device(struct dm_thin_device
*td
);
130 dm_thin_id
dm_thin_dev_id(struct dm_thin_device
*td
);
132 struct dm_thin_lookup_result
{
139 * -EWOULDBLOCK iff @can_block is set and would block.
140 * -ENODATA iff that mapping is not present.
143 int dm_thin_find_block(struct dm_thin_device
*td
, dm_block_t block
,
144 int can_block
, struct dm_thin_lookup_result
*result
);
147 * Obtain an unused block.
149 int dm_pool_alloc_data_block(struct dm_pool_metadata
*pmd
, dm_block_t
*result
);
152 * Insert or remove block.
154 int dm_thin_insert_block(struct dm_thin_device
*td
, dm_block_t block
,
155 dm_block_t data_block
);
157 int dm_thin_remove_block(struct dm_thin_device
*td
, dm_block_t block
);
162 bool dm_thin_changed_this_transaction(struct dm_thin_device
*td
);
164 bool dm_thin_aborted_changes(struct dm_thin_device
*td
);
166 int dm_thin_get_highest_mapped_block(struct dm_thin_device
*td
,
167 dm_block_t
*highest_mapped
);
169 int dm_thin_get_mapped_count(struct dm_thin_device
*td
, dm_block_t
*result
);
171 int dm_pool_get_free_block_count(struct dm_pool_metadata
*pmd
,
174 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata
*pmd
,
177 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata
*pmd
,
180 int dm_pool_get_data_block_size(struct dm_pool_metadata
*pmd
, sector_t
*result
);
182 int dm_pool_get_data_dev_size(struct dm_pool_metadata
*pmd
, dm_block_t
*result
);
185 * Returns -ENOSPC if the new size is too small and already allocated
186 * blocks would be lost.
188 int dm_pool_resize_data_dev(struct dm_pool_metadata
*pmd
, dm_block_t new_size
);
189 int dm_pool_resize_metadata_dev(struct dm_pool_metadata
*pmd
, dm_block_t new_size
);
192 * Flicks the underlying block manager into read only mode, so you know
193 * that nothing is changing.
195 void dm_pool_metadata_read_only(struct dm_pool_metadata
*pmd
);
197 int dm_pool_register_metadata_threshold(struct dm_pool_metadata
*pmd
,
198 dm_block_t threshold
,
199 dm_sm_threshold_fn fn
,
202 /*----------------------------------------------------------------*/