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
12 typedef sector_t region_t;
13
14 struct dirty_log_type;
15
16 struct dirty_log {
17 struct dirty_log_type *type;
18 void *context;
19 };
20
21 struct 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 (*suspend)(struct dirty_log *log);
36 int (*resume)(struct dirty_log *log);
37
38 /*
39 * Retrieves the smallest size of region that the log can
40 * deal with.
41 */
42 uint32_t (*get_region_size)(struct dirty_log *log);
43
44 /*
45 * A predicate to say whether a region is clean or not.
46 * May block.
47 */
48 int (*is_clean)(struct dirty_log *log, region_t region);
49
50 /*
51 * Returns: 0, 1, -EWOULDBLOCK, < 0
52 *
53 * A predicate function to check the area given by
54 * [sector, sector + len) is in sync.
55 *
56 * If -EWOULDBLOCK is returned the state of the region is
57 * unknown, typically this will result in a read being
58 * passed to a daemon to deal with, since a daemon is
59 * allowed to block.
60 */
61 int (*in_sync)(struct dirty_log *log, region_t region, int can_block);
62
63 /*
64 * Flush the current log state (eg, to disk). This
65 * function may block.
66 */
67 int (*flush)(struct dirty_log *log);
68
69 /*
70 * Mark an area as clean or dirty. These functions may
71 * block, though for performance reasons blocking should
72 * be extremely rare (eg, allocating another chunk of
73 * memory for some reason).
74 */
75 void (*mark_region)(struct dirty_log *log, region_t region);
76 void (*clear_region)(struct dirty_log *log, region_t region);
77
78 /*
79 * Returns: <0 (error), 0 (no region), 1 (region)
80 *
81 * The mirrord will need perform recovery on regions of
82 * the mirror that are in the NOSYNC state. This
83 * function asks the log to tell the caller about the
84 * next region that this machine should recover.
85 *
86 * Do not confuse this function with 'in_sync()', one
87 * tells you if an area is synchronised, the other
88 * assigns recovery work.
89 */
90 int (*get_resync_work)(struct dirty_log *log, region_t *region);
91
92 /*
93 * This notifies the log that the resync of an area has
94 * been completed. The log should then mark this region
95 * as CLEAN.
96 */
97 void (*complete_resync_work)(struct dirty_log *log,
98 region_t region, int success);
99
100 /*
101 * Returns the number of regions that are in sync.
102 */
103 region_t (*get_sync_count)(struct dirty_log *log);
104
105 /*
106 * Support function for mirror status requests.
107 */
108 int (*status)(struct dirty_log *log, status_type_t status_type,
109 char *result, unsigned int maxlen);
110 };
111
112 int dm_register_dirty_log_type(struct dirty_log_type *type);
113 int dm_unregister_dirty_log_type(struct dirty_log_type *type);
114
115
116 /*
117 * Make sure you use these two functions, rather than calling
118 * type->constructor/destructor() directly.
119 */
120 struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
121 unsigned int argc, char **argv);
122 void dm_destroy_dirty_log(struct dirty_log *log);
123
124 /*
125 * init/exit functions.
126 */
127 int dm_dirty_log_init(void);
128 void dm_dirty_log_exit(void);
129
130 #endif
131
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