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