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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 | ||
26 | static void transient_destroy(struct dm_exception_store *store) | |
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; |
4db6bfe0 AK |
43 | sector_t size = get_dev_size(store->snap->cow->bdev); |
44 | ||
45 | if (size < (tc->next_free + store->snap->chunk_size)) | |
46 | return -1; | |
47 | ||
48 | e->new_chunk = sector_to_chunk(store->snap, tc->next_free); | |
49 | tc->next_free += store->snap->chunk_size; | |
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; | |
67 | *denominator = get_dev_size(store->snap->cow->bdev); | |
68 | } | |
69 | ||
70 | int dm_create_transient(struct dm_exception_store *store) | |
71 | { | |
72 | struct transient_c *tc; | |
73 | ||
b2a11465 JB |
74 | store->type.dtr = transient_destroy; |
75 | store->type.read_metadata = transient_read_metadata; | |
76 | store->type.prepare_exception = transient_prepare_exception; | |
77 | store->type.commit_exception = transient_commit_exception; | |
78 | store->type.drop_snapshot = NULL; | |
79 | store->type.fraction_full = transient_fraction_full; | |
4db6bfe0 AK |
80 | |
81 | tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); | |
82 | if (!tc) | |
83 | return -ENOMEM; | |
84 | ||
85 | tc->next_free = 0; | |
86 | store->context = tc; | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | int dm_transient_snapshot_init(void) | |
92 | { | |
93 | return 0; | |
94 | } | |
95 | ||
96 | void dm_transient_snapshot_exit(void) | |
97 | { | |
98 | } |