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 | * |
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. |
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. |
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. |
93 | */ |
94 | int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd); |
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 | * |
131 | * dm_clone_metadata_pre_commit() |
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 | */ |
159 | unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd); |
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 */ |
178 | |