1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * Copyright (C) 2010-2011 Red Hat, Inc. |
4 | * |
5 | * This file is released under the GPL. |
6 | */ |
7 | |
8 | #ifndef DM_THIN_METADATA_H |
9 | #define DM_THIN_METADATA_H |
10 | |
11 | #include "persistent-data/dm-block-manager.h" |
12 | #include "persistent-data/dm-space-map.h" |
13 | #include "persistent-data/dm-space-map-metadata.h" |
14 | |
15 | #define THIN_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE |
16 | |
17 | /* |
18 | * The metadata device is currently limited in size. |
19 | */ |
20 | #define THIN_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS |
21 | |
22 | /* |
23 | * A metadata device larger than 16GB triggers a warning. |
24 | */ |
25 | #define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) |
26 | |
27 | /*----------------------------------------------------------------*/ |
28 | |
29 | /* |
30 | * Thin metadata superblock flags. |
31 | */ |
32 | #define THIN_METADATA_NEEDS_CHECK_FLAG (1 << 0) |
33 | |
34 | struct dm_pool_metadata; |
35 | struct dm_thin_device; |
36 | |
37 | /* |
38 | * Device identifier |
39 | */ |
40 | typedef uint64_t dm_thin_id; |
41 | |
42 | /* |
43 | * Reopens or creates a new, empty metadata volume. |
44 | */ |
45 | struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, |
46 | sector_t data_block_size, |
47 | bool format_device); |
48 | |
49 | int dm_pool_metadata_close(struct dm_pool_metadata *pmd); |
50 | |
51 | /* |
52 | * Compat feature flags. Any incompat flags beyond the ones |
53 | * specified below will prevent use of the thin metadata. |
54 | */ |
55 | #define THIN_FEATURE_COMPAT_SUPP 0UL |
56 | #define THIN_FEATURE_COMPAT_RO_SUPP 0UL |
57 | #define THIN_FEATURE_INCOMPAT_SUPP 0UL |
58 | |
59 | /* |
60 | * Device creation/deletion. |
61 | */ |
62 | int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev); |
63 | |
64 | /* |
65 | * An internal snapshot. |
66 | * |
67 | * You can only snapshot a quiesced origin i.e. one that is either |
68 | * suspended or not instanced at all. |
69 | */ |
70 | int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev, |
71 | dm_thin_id origin); |
72 | |
73 | /* |
74 | * Deletes a virtual device from the metadata. It _is_ safe to call this |
75 | * when that device is open. Operations on that device will just start |
76 | * failing. You still need to call close() on the device. |
77 | */ |
78 | int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, |
79 | dm_thin_id dev); |
80 | |
81 | /* |
82 | * Commits _all_ metadata changes: device creation, deletion, mapping |
83 | * updates. |
84 | */ |
85 | int dm_pool_commit_metadata(struct dm_pool_metadata *pmd); |
86 | |
87 | /* |
88 | * Discards all uncommitted changes. Rereads the superblock, rolling back |
89 | * to the last good transaction. Thin devices remain open. |
90 | * dm_thin_aborted_changes() tells you if they had uncommitted changes. |
91 | * |
92 | * If this call fails it's only useful to call dm_pool_metadata_close(). |
93 | * All other methods will fail with -EINVAL. |
94 | */ |
95 | int dm_pool_abort_metadata(struct dm_pool_metadata *pmd); |
96 | |
97 | /* |
98 | * Set/get userspace transaction id. |
99 | */ |
100 | int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, |
101 | uint64_t current_id, |
102 | uint64_t new_id); |
103 | |
104 | int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, |
105 | uint64_t *result); |
106 | |
107 | /* |
108 | * Hold/get root for userspace transaction. |
109 | * |
110 | * The metadata snapshot is a copy of the current superblock (minus the |
111 | * space maps). Userland can access the data structures for READ |
112 | * operations only. A small performance hit is incurred by providing this |
113 | * copy of the metadata to userland due to extra copy-on-write operations |
114 | * on the metadata nodes. Release this as soon as you finish with it. |
115 | */ |
116 | int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd); |
117 | int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd); |
118 | |
119 | int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd, |
120 | dm_block_t *result); |
121 | |
122 | /* |
123 | * Actions on a single virtual device. |
124 | */ |
125 | |
126 | /* |
127 | * Opening the same device more than once will fail with -EBUSY. |
128 | */ |
129 | int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, |
130 | struct dm_thin_device **td); |
131 | |
132 | int dm_pool_close_thin_device(struct dm_thin_device *td); |
133 | |
134 | dm_thin_id dm_thin_dev_id(struct dm_thin_device *td); |
135 | |
136 | struct dm_thin_lookup_result { |
137 | dm_block_t block; |
138 | bool shared:1; |
139 | }; |
140 | |
141 | /* |
142 | * Returns: |
143 | * -EWOULDBLOCK iff @can_issue_io is set and would issue IO |
144 | * -ENODATA iff that mapping is not present. |
145 | * 0 success |
146 | */ |
147 | int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, |
148 | int can_issue_io, struct dm_thin_lookup_result *result); |
149 | |
150 | /* |
151 | * Retrieve the next run of contiguously mapped blocks. Useful for working |
152 | * out where to break up IO. Returns 0 on success, < 0 on error. |
153 | */ |
154 | int dm_thin_find_mapped_range(struct dm_thin_device *td, |
155 | dm_block_t begin, dm_block_t end, |
156 | dm_block_t *thin_begin, dm_block_t *thin_end, |
157 | dm_block_t *pool_begin, bool *maybe_shared); |
158 | |
159 | /* |
160 | * Obtain an unused block. |
161 | */ |
162 | int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result); |
163 | |
164 | /* |
165 | * Insert or remove block. |
166 | */ |
167 | int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, |
168 | dm_block_t data_block); |
169 | |
170 | int dm_thin_remove_range(struct dm_thin_device *td, |
171 | dm_block_t begin, dm_block_t end); |
172 | |
173 | /* |
174 | * Queries. |
175 | */ |
176 | bool dm_thin_changed_this_transaction(struct dm_thin_device *td); |
177 | |
178 | bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd); |
179 | |
180 | bool dm_thin_aborted_changes(struct dm_thin_device *td); |
181 | |
182 | int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, |
183 | dm_block_t *highest_mapped); |
184 | |
185 | int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result); |
186 | |
187 | int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, |
188 | dm_block_t *result); |
189 | |
190 | int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, |
191 | dm_block_t *result); |
192 | |
193 | int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, |
194 | dm_block_t *result); |
195 | |
196 | int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); |
197 | |
198 | int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result); |
199 | |
200 | int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e); |
201 | int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e); |
202 | |
203 | /* |
204 | * Returns -ENOSPC if the new size is too small and already allocated |
205 | * blocks would be lost. |
206 | */ |
207 | int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); |
208 | int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); |
209 | |
210 | /* |
211 | * Flicks the underlying block manager into read only mode, so you know |
212 | * that nothing is changing. |
213 | */ |
214 | void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd); |
215 | void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd); |
216 | |
217 | int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, |
218 | dm_block_t threshold, |
219 | dm_sm_threshold_fn fn, |
220 | void *context); |
221 | |
222 | /* |
223 | * Updates the superblock immediately. |
224 | */ |
225 | int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd); |
226 | bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd); |
227 | |
228 | /* |
229 | * Issue any prefetches that may be useful. |
230 | */ |
231 | void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd); |
232 | |
233 | /* Pre-commit callback */ |
234 | typedef int (*dm_pool_pre_commit_fn)(void *context); |
235 | |
236 | void dm_pool_register_pre_commit_callback(struct dm_pool_metadata *pmd, |
237 | dm_pool_pre_commit_fn fn, |
238 | void *context); |
239 | |
240 | /*----------------------------------------------------------------*/ |
241 | |
242 | #endif |
243 | |