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