Commit | Line | Data |
---|---|---|
7431b783 NT |
1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* | |
3 | * Copyright (C) 2019 Arrikto, Inc. All Rights Reserved. | |
4 | */ | |
5 | ||
6 | #ifndef DM_CLONE_METADATA_H | |
7 | #define DM_CLONE_METADATA_H | |
8 | ||
9 | #include "persistent-data/dm-block-manager.h" | |
10 | #include "persistent-data/dm-space-map-metadata.h" | |
11 | ||
12 | #define DM_CLONE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE | |
13 | ||
14 | /* | |
15 | * The metadata device is currently limited in size. | |
16 | */ | |
17 | #define DM_CLONE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS | |
18 | ||
19 | /* | |
20 | * A metadata device larger than 16GB triggers a warning. | |
21 | */ | |
22 | #define DM_CLONE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) | |
23 | ||
24 | #define SPACE_MAP_ROOT_SIZE 128 | |
25 | ||
26 | /* dm-clone metadata */ | |
27 | struct dm_clone_metadata; | |
28 | ||
29 | /* | |
30 | * Set region status to hydrated. | |
31 | * | |
32 | * @cmd: The dm-clone metadata | |
33 | * @region_nr: The region number | |
34 | * | |
35 | * This function doesn't block, so it's safe to call it from interrupt context. | |
36 | */ | |
37 | int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr); | |
38 | ||
39 | /* | |
40 | * Set status of all regions in the provided range to hydrated, if not already | |
41 | * hydrated. | |
42 | * | |
43 | * @cmd: The dm-clone metadata | |
44 | * @start: Starting region number | |
45 | * @nr_regions: Number of regions in the range | |
46 | * | |
6ca43ed8 MP |
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. | |
7431b783 NT |
50 | */ |
51 | int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start, | |
52 | unsigned long nr_regions); | |
53 | ||
54 | /* | |
55 | * Read existing or create fresh metadata. | |
56 | * | |
57 | * @bdev: The device storing the metadata | |
58 | * @target_size: The target size | |
59 | * @region_size: The region size | |
60 | * | |
61 | * @returns: The dm-clone metadata | |
62 | * | |
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. | |
66 | */ | |
67 | struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev, | |
68 | sector_t target_size, | |
69 | sector_t region_size); | |
70 | ||
71 | /* | |
72 | * Free the resources related to metadata management. | |
73 | */ | |
74 | void dm_clone_metadata_close(struct dm_clone_metadata *cmd); | |
75 | ||
76 | /* | |
77 | * Commit dm-clone metadata to disk. | |
8fdbfe8d NT |
78 | * |
79 | * We use a two phase commit: | |
80 | * | |
81 | * 1. dm_clone_metadata_pre_commit(): Prepare the current transaction for | |
82 | * committing. After this is called, all subsequent metadata updates, done | |
83 | * through either dm_clone_set_region_hydrated() or | |
84 | * dm_clone_cond_set_range(), will be part of the **next** transaction. | |
85 | * | |
86 | * 2. dm_clone_metadata_commit(): Actually commit the current transaction to | |
87 | * disk and start a new transaction. | |
88 | * | |
89 | * This allows dm-clone to flush the destination device after step (1) to | |
90 | * ensure that all freshly hydrated regions, for which we are updating the | |
91 | * metadata, are properly written to non-volatile storage and won't be lost in | |
92 | * case of a crash. | |
7431b783 | 93 | */ |
8fdbfe8d | 94 | int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd); |
7431b783 NT |
95 | int dm_clone_metadata_commit(struct dm_clone_metadata *cmd); |
96 | ||
97 | /* | |
98 | * Reload the in core copy of the on-disk bitmap. | |
99 | * | |
100 | * This should be used after aborting a metadata transaction and setting the | |
101 | * metadata to read-only, to invalidate the in-core cache and make it match the | |
102 | * on-disk metadata. | |
103 | * | |
104 | * WARNING: It must not be called concurrently with either | |
105 | * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it updates | |
106 | * the region bitmap without taking the relevant spinlock. We don't take the | |
107 | * spinlock because dm_clone_reload_in_core_bitset() does I/O, so it may block. | |
108 | * | |
109 | * But, it's safe to use it after calling dm_clone_metadata_set_read_only(), | |
110 | * because the latter sets the metadata to read-only mode. Both | |
111 | * dm_clone_set_region_hydrated() and dm_clone_cond_set_range() refuse to touch | |
112 | * the region bitmap, after calling dm_clone_metadata_set_read_only(). | |
113 | */ | |
114 | int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd); | |
115 | ||
116 | /* | |
117 | * Check whether dm-clone's metadata changed this transaction. | |
118 | */ | |
119 | bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd); | |
120 | ||
121 | /* | |
122 | * Abort current metadata transaction and rollback metadata to the last | |
123 | * committed transaction. | |
124 | */ | |
125 | int dm_clone_metadata_abort(struct dm_clone_metadata *cmd); | |
126 | ||
127 | /* | |
128 | * Switches metadata to a read only mode. Once read-only mode has been entered | |
129 | * the following functions will return -EPERM: | |
130 | * | |
8fdbfe8d | 131 | * dm_clone_metadata_pre_commit() |
7431b783 NT |
132 | * dm_clone_metadata_commit() |
133 | * dm_clone_set_region_hydrated() | |
134 | * dm_clone_cond_set_range() | |
135 | * dm_clone_metadata_abort() | |
136 | */ | |
137 | void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd); | |
138 | void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd); | |
139 | ||
140 | /* | |
141 | * Returns true if the hydration of the destination device is finished. | |
142 | */ | |
143 | bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd); | |
144 | ||
145 | /* | |
146 | * Returns true if region @region_nr is hydrated. | |
147 | */ | |
148 | bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr); | |
149 | ||
150 | /* | |
151 | * Returns true if all the regions in the range are hydrated. | |
152 | */ | |
153 | bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd, | |
154 | unsigned long start, unsigned long nr_regions); | |
155 | ||
156 | /* | |
157 | * Returns the number of hydrated regions. | |
158 | */ | |
81d5553d | 159 | unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd); |
7431b783 NT |
160 | |
161 | /* | |
162 | * Returns the first unhydrated region with region_nr >= @start | |
163 | */ | |
164 | unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd, | |
165 | unsigned long start); | |
166 | ||
167 | /* | |
168 | * Get the number of free metadata blocks. | |
169 | */ | |
170 | int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, dm_block_t *result); | |
171 | ||
172 | /* | |
173 | * Get the total number of metadata blocks. | |
174 | */ | |
175 | int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, dm_block_t *result); | |
176 | ||
177 | #endif /* DM_CLONE_METADATA_H */ |