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3bd94003 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
4db6bfe0 AK |
2 | /* |
3 | * Copyright (C) 2001-2002 Sistina Software (UK) Limited. | |
4 | * Copyright (C) 2006-2008 Red Hat GmbH | |
5 | * | |
6 | * This file is released under the GPL. | |
7 | */ | |
8 | ||
9 | #include "dm-exception-store.h" | |
4db6bfe0 AK |
10 | |
11 | #include <linux/mm.h> | |
12 | #include <linux/pagemap.h> | |
13 | #include <linux/vmalloc.h> | |
daaa5f7c | 14 | #include <linux/export.h> |
4db6bfe0 AK |
15 | #include <linux/slab.h> |
16 | #include <linux/dm-io.h> | |
17 | ||
18 | #define DM_MSG_PREFIX "transient snapshot" | |
19 | ||
a4a82ce3 HM |
20 | /* |
21 | *--------------------------------------------------------------- | |
4db6bfe0 | 22 | * Implementation of the store for non-persistent snapshots. |
a4a82ce3 HM |
23 | *--------------------------------------------------------------- |
24 | */ | |
4db6bfe0 AK |
25 | struct transient_c { |
26 | sector_t next_free; | |
27 | }; | |
28 | ||
493df71c | 29 | static void transient_dtr(struct dm_exception_store *store) |
4db6bfe0 AK |
30 | { |
31 | kfree(store->context); | |
32 | } | |
33 | ||
a159c1ac JB |
34 | static int transient_read_metadata(struct dm_exception_store *store, |
35 | int (*callback)(void *callback_context, | |
36 | chunk_t old, chunk_t new), | |
37 | void *callback_context) | |
4db6bfe0 AK |
38 | { |
39 | return 0; | |
40 | } | |
41 | ||
a159c1ac | 42 | static int transient_prepare_exception(struct dm_exception_store *store, |
1d4989c8 | 43 | struct dm_exception *e) |
4db6bfe0 | 44 | { |
b2a11465 | 45 | struct transient_c *tc = store->context; |
fc56f6fb | 46 | sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev); |
4db6bfe0 | 47 | |
d0216849 | 48 | if (size < (tc->next_free + store->chunk_size)) |
4db6bfe0 AK |
49 | return -1; |
50 | ||
71fab00a | 51 | e->new_chunk = sector_to_chunk(store, tc->next_free); |
d0216849 | 52 | tc->next_free += store->chunk_size; |
4db6bfe0 AK |
53 | |
54 | return 0; | |
55 | } | |
56 | ||
a159c1ac | 57 | static void transient_commit_exception(struct dm_exception_store *store, |
385277bf | 58 | struct dm_exception *e, int valid, |
8ca817c4 | 59 | void (*callback)(void *, int success), |
a159c1ac | 60 | void *callback_context) |
4db6bfe0 AK |
61 | { |
62 | /* Just succeed */ | |
385277bf | 63 | callback(callback_context, valid); |
4db6bfe0 AK |
64 | } |
65 | ||
985903bb MS |
66 | static void transient_usage(struct dm_exception_store *store, |
67 | sector_t *total_sectors, | |
68 | sector_t *sectors_allocated, | |
69 | sector_t *metadata_sectors) | |
4db6bfe0 | 70 | { |
985903bb | 71 | *sectors_allocated = ((struct transient_c *) store->context)->next_free; |
fc56f6fb | 72 | *total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev); |
985903bb | 73 | *metadata_sectors = 0; |
4db6bfe0 AK |
74 | } |
75 | ||
b0d3cc01 | 76 | static int transient_ctr(struct dm_exception_store *store, char *options) |
4db6bfe0 AK |
77 | { |
78 | struct transient_c *tc; | |
79 | ||
4db6bfe0 AK |
80 | tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); |
81 | if (!tc) | |
82 | return -ENOMEM; | |
83 | ||
84 | tc->next_free = 0; | |
85 | store->context = tc; | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
86a3238c | 90 | static unsigned int transient_status(struct dm_exception_store *store, |
1e302a92 | 91 | status_type_t status, char *result, |
86a3238c | 92 | unsigned int maxlen) |
493df71c | 93 | { |
86a3238c | 94 | unsigned int sz = 0; |
1e302a92 JB |
95 | |
96 | switch (status) { | |
97 | case STATUSTYPE_INFO: | |
98 | break; | |
99 | case STATUSTYPE_TABLE: | |
fc56f6fb | 100 | DMEMIT(" N %llu", (unsigned long long)store->chunk_size); |
8ec45662 TS |
101 | break; |
102 | case STATUSTYPE_IMA: | |
103 | *result = '\0'; | |
104 | break; | |
1e302a92 | 105 | } |
493df71c JB |
106 | |
107 | return sz; | |
108 | } | |
109 | ||
110 | static struct dm_exception_store_type _transient_type = { | |
111 | .name = "transient", | |
112 | .module = THIS_MODULE, | |
113 | .ctr = transient_ctr, | |
114 | .dtr = transient_dtr, | |
115 | .read_metadata = transient_read_metadata, | |
116 | .prepare_exception = transient_prepare_exception, | |
117 | .commit_exception = transient_commit_exception, | |
985903bb | 118 | .usage = transient_usage, |
493df71c JB |
119 | .status = transient_status, |
120 | }; | |
121 | ||
122 | static struct dm_exception_store_type _transient_compat_type = { | |
123 | .name = "N", | |
124 | .module = THIS_MODULE, | |
125 | .ctr = transient_ctr, | |
126 | .dtr = transient_dtr, | |
127 | .read_metadata = transient_read_metadata, | |
128 | .prepare_exception = transient_prepare_exception, | |
129 | .commit_exception = transient_commit_exception, | |
985903bb | 130 | .usage = transient_usage, |
493df71c JB |
131 | .status = transient_status, |
132 | }; | |
133 | ||
4db6bfe0 AK |
134 | int dm_transient_snapshot_init(void) |
135 | { | |
493df71c JB |
136 | int r; |
137 | ||
138 | r = dm_exception_store_type_register(&_transient_type); | |
139 | if (r) { | |
140 | DMWARN("Unable to register transient exception store type"); | |
141 | return r; | |
142 | } | |
143 | ||
144 | r = dm_exception_store_type_register(&_transient_compat_type); | |
145 | if (r) { | |
2e84fecf | 146 | DMWARN("Unable to register old-style transient exception store type"); |
493df71c JB |
147 | dm_exception_store_type_unregister(&_transient_type); |
148 | return r; | |
149 | } | |
150 | ||
151 | return r; | |
4db6bfe0 AK |
152 | } |
153 | ||
154 | void dm_transient_snapshot_exit(void) | |
155 | { | |
493df71c JB |
156 | dm_exception_store_type_unregister(&_transient_type); |
157 | dm_exception_store_type_unregister(&_transient_compat_type); | |
4db6bfe0 | 158 | } |