tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * Copyright (C) 2003 Sistina Software
3 *
4 * This file is released under the LGPL.
5 */
6
7#ifndef DM_DIRTY_LOG
8#define DM_DIRTY_LOG
9
10#include "dm.h"
11
12typedef sector_t region_t;
13
14struct dirty_log_type;
15
16struct dirty_log {
17 struct dirty_log_type *type;
18 void *context;
19};
20
21struct dirty_log_type {
22 struct list_head list;
23 const char *name;
24 struct module *module;
25 unsigned int use_count;
26
27 int (*ctr)(struct dirty_log *log, struct dm_target *ti,
28 unsigned int argc, char **argv);
29 void (*dtr)(struct dirty_log *log);
30
31 /*
32 * There are times when we don't want the log to touch
33 * the disk.
34 */
35 int (*presuspend)(struct dirty_log *log);
36 int (*postsuspend)(struct dirty_log *log);
37 int (*resume)(struct dirty_log *log);
38
39 /*
40 * Retrieves the smallest size of region that the log can
41 * deal with.
42 */
43 uint32_t (*get_region_size)(struct dirty_log *log);
44
45 /*
46 * A predicate to say whether a region is clean or not.
47 * May block.
48 */
49 int (*is_clean)(struct dirty_log *log, region_t region);
50
51 /*
52 * Returns: 0, 1, -EWOULDBLOCK, < 0
53 *
54 * A predicate function to check the area given by
55 * [sector, sector + len) is in sync.
56 *
57 * If -EWOULDBLOCK is returned the state of the region is
58 * unknown, typically this will result in a read being
59 * passed to a daemon to deal with, since a daemon is
60 * allowed to block.
61 */
62 int (*in_sync)(struct dirty_log *log, region_t region, int can_block);
63
64 /*
65 * Flush the current log state (eg, to disk). This
66 * function may block.
67 */
68 int (*flush)(struct dirty_log *log);
69
70 /*
71 * Mark an area as clean or dirty. These functions may
72 * block, though for performance reasons blocking should
73 * be extremely rare (eg, allocating another chunk of
74 * memory for some reason).
75 */
76 void (*mark_region)(struct dirty_log *log, region_t region);
77 void (*clear_region)(struct dirty_log *log, region_t region);
78
79 /*
80 * Returns: <0 (error), 0 (no region), 1 (region)
81 *
82 * The mirrord will need perform recovery on regions of
83 * the mirror that are in the NOSYNC state. This
84 * function asks the log to tell the caller about the
85 * next region that this machine should recover.
86 *
87 * Do not confuse this function with 'in_sync()', one
88 * tells you if an area is synchronised, the other
89 * assigns recovery work.
90 */
91 int (*get_resync_work)(struct dirty_log *log, region_t *region);
92
93 /*
94 * This notifies the log that the resync status of a region
95 * has changed. It also clears the region from the recovering
96 * list (if present).
97 */
98 void (*set_region_sync)(struct dirty_log *log,
99 region_t region, int in_sync);
100
101 /*
102 * Returns the number of regions that are in sync.
103 */
104 region_t (*get_sync_count)(struct dirty_log *log);
105
106 /*
107 * Support function for mirror status requests.
108 */
109 int (*status)(struct dirty_log *log, status_type_t status_type,
110 char *result, unsigned int maxlen);
111};
112
113int dm_register_dirty_log_type(struct dirty_log_type *type);
114int dm_unregister_dirty_log_type(struct dirty_log_type *type);
115
116
117/*
118 * Make sure you use these two functions, rather than calling
119 * type->constructor/destructor() directly.
120 */
121struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
122 unsigned int argc, char **argv);
123void dm_destroy_dirty_log(struct dirty_log *log);
124
125/*
126 * init/exit functions.
127 */
128int dm_dirty_log_init(void);
129void dm_dirty_log_exit(void);
130
131#endif