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4db6bfe0 AK |
1 | /* |
2 | * Copyright (C) 2001-2002 Sistina Software (UK) Limited. | |
3 | * Copyright (C) 2006-2008 Red Hat GmbH | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
8 | #include "dm-exception-store.h" | |
4db6bfe0 AK |
9 | |
10 | #include <linux/mm.h> | |
11 | #include <linux/pagemap.h> | |
12 | #include <linux/vmalloc.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/dm-io.h> | |
15 | ||
16 | #define DM_MSG_PREFIX "transient snapshot" | |
17 | ||
18 | /*----------------------------------------------------------------- | |
19 | * Implementation of the store for non-persistent snapshots. | |
20 | *---------------------------------------------------------------*/ | |
21 | struct transient_c { | |
22 | sector_t next_free; | |
23 | }; | |
24 | ||
493df71c | 25 | static void transient_dtr(struct dm_exception_store *store) |
4db6bfe0 AK |
26 | { |
27 | kfree(store->context); | |
28 | } | |
29 | ||
a159c1ac JB |
30 | static int transient_read_metadata(struct dm_exception_store *store, |
31 | int (*callback)(void *callback_context, | |
32 | chunk_t old, chunk_t new), | |
33 | void *callback_context) | |
4db6bfe0 AK |
34 | { |
35 | return 0; | |
36 | } | |
37 | ||
a159c1ac JB |
38 | static int transient_prepare_exception(struct dm_exception_store *store, |
39 | struct dm_snap_exception *e) | |
4db6bfe0 | 40 | { |
b2a11465 | 41 | struct transient_c *tc = store->context; |
49beb2b8 | 42 | sector_t size = get_dev_size(store->cow->bdev); |
4db6bfe0 | 43 | |
d0216849 | 44 | if (size < (tc->next_free + store->chunk_size)) |
4db6bfe0 AK |
45 | return -1; |
46 | ||
71fab00a | 47 | e->new_chunk = sector_to_chunk(store, tc->next_free); |
d0216849 | 48 | tc->next_free += store->chunk_size; |
4db6bfe0 AK |
49 | |
50 | return 0; | |
51 | } | |
52 | ||
a159c1ac JB |
53 | static void transient_commit_exception(struct dm_exception_store *store, |
54 | struct dm_snap_exception *e, | |
55 | void (*callback) (void *, int success), | |
56 | void *callback_context) | |
4db6bfe0 AK |
57 | { |
58 | /* Just succeed */ | |
59 | callback(callback_context, 1); | |
60 | } | |
61 | ||
62 | static void transient_fraction_full(struct dm_exception_store *store, | |
63 | sector_t *numerator, sector_t *denominator) | |
64 | { | |
65 | *numerator = ((struct transient_c *) store->context)->next_free; | |
49beb2b8 | 66 | *denominator = get_dev_size(store->cow->bdev); |
4db6bfe0 AK |
67 | } |
68 | ||
493df71c JB |
69 | static int transient_ctr(struct dm_exception_store *store, |
70 | unsigned argc, char **argv) | |
4db6bfe0 AK |
71 | { |
72 | struct transient_c *tc; | |
73 | ||
4db6bfe0 AK |
74 | tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); |
75 | if (!tc) | |
76 | return -ENOMEM; | |
77 | ||
78 | tc->next_free = 0; | |
79 | store->context = tc; | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
1e302a92 JB |
84 | static unsigned transient_status(struct dm_exception_store *store, |
85 | status_type_t status, char *result, | |
86 | unsigned maxlen) | |
493df71c | 87 | { |
1e302a92 JB |
88 | unsigned sz = 0; |
89 | ||
90 | switch (status) { | |
91 | case STATUSTYPE_INFO: | |
92 | break; | |
93 | case STATUSTYPE_TABLE: | |
94 | DMEMIT(" %s N %llu", store->cow->name, | |
95 | (unsigned long long)store->chunk_size); | |
96 | } | |
493df71c JB |
97 | |
98 | return sz; | |
99 | } | |
100 | ||
101 | static struct dm_exception_store_type _transient_type = { | |
102 | .name = "transient", | |
103 | .module = THIS_MODULE, | |
104 | .ctr = transient_ctr, | |
105 | .dtr = transient_dtr, | |
106 | .read_metadata = transient_read_metadata, | |
107 | .prepare_exception = transient_prepare_exception, | |
108 | .commit_exception = transient_commit_exception, | |
109 | .fraction_full = transient_fraction_full, | |
110 | .status = transient_status, | |
111 | }; | |
112 | ||
113 | static struct dm_exception_store_type _transient_compat_type = { | |
114 | .name = "N", | |
115 | .module = THIS_MODULE, | |
116 | .ctr = transient_ctr, | |
117 | .dtr = transient_dtr, | |
118 | .read_metadata = transient_read_metadata, | |
119 | .prepare_exception = transient_prepare_exception, | |
120 | .commit_exception = transient_commit_exception, | |
121 | .fraction_full = transient_fraction_full, | |
122 | .status = transient_status, | |
123 | }; | |
124 | ||
4db6bfe0 AK |
125 | int dm_transient_snapshot_init(void) |
126 | { | |
493df71c JB |
127 | int r; |
128 | ||
129 | r = dm_exception_store_type_register(&_transient_type); | |
130 | if (r) { | |
131 | DMWARN("Unable to register transient exception store type"); | |
132 | return r; | |
133 | } | |
134 | ||
135 | r = dm_exception_store_type_register(&_transient_compat_type); | |
136 | if (r) { | |
137 | DMWARN("Unable to register old-style transient " | |
138 | "exception store type"); | |
139 | dm_exception_store_type_unregister(&_transient_type); | |
140 | return r; | |
141 | } | |
142 | ||
143 | return r; | |
4db6bfe0 AK |
144 | } |
145 | ||
146 | void dm_transient_snapshot_exit(void) | |
147 | { | |
493df71c JB |
148 | dm_exception_store_type_unregister(&_transient_type); |
149 | dm_exception_store_type_unregister(&_transient_compat_type); | |
4db6bfe0 | 150 | } |