1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * Copyright (C) 2003 Sistina Software |
4 | * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
5 | * |
6 | * Device-Mapper dirty region log. |
7 | * |
8 | * This file is released under the LGPL. |
9 | */ |
10 | |
11 | #ifndef _LINUX_DM_DIRTY_LOG |
12 | #define _LINUX_DM_DIRTY_LOG |
13 | |
14 | #ifdef __KERNEL__ |
15 | |
16 | #include <linux/types.h> |
17 | #include <linux/device-mapper.h> |
18 | |
19 | typedef sector_t region_t; |
20 | |
21 | struct dm_dirty_log_type; |
22 | |
23 | struct dm_dirty_log { |
24 | struct dm_dirty_log_type *type; |
25 | int (*flush_callback_fn)(struct dm_target *ti); |
26 | void *context; |
27 | }; |
28 | |
29 | struct dm_dirty_log_type { |
30 | const char *name; |
31 | struct module *module; |
32 | |
33 | /* For internal device-mapper use */ |
34 | struct list_head list; |
35 | |
36 | int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti, |
37 | unsigned int argc, char **argv); |
38 | void (*dtr)(struct dm_dirty_log *log); |
39 | |
40 | /* |
41 | * There are times when we don't want the log to touch |
42 | * the disk. |
43 | */ |
44 | int (*presuspend)(struct dm_dirty_log *log); |
45 | int (*postsuspend)(struct dm_dirty_log *log); |
46 | int (*resume)(struct dm_dirty_log *log); |
47 | |
48 | /* |
49 | * Retrieves the smallest size of region that the log can |
50 | * deal with. |
51 | */ |
52 | uint32_t (*get_region_size)(struct dm_dirty_log *log); |
53 | |
54 | /* |
55 | * A predicate to say whether a region is clean or not. |
56 | * May block. |
57 | */ |
58 | int (*is_clean)(struct dm_dirty_log *log, region_t region); |
59 | |
60 | /* |
61 | * Returns: 0, 1, -EWOULDBLOCK, < 0 |
62 | * |
63 | * A predicate function to check the area given by |
64 | * [sector, sector + len) is in sync. |
65 | * |
66 | * If -EWOULDBLOCK is returned the state of the region is |
67 | * unknown, typically this will result in a read being |
68 | * passed to a daemon to deal with, since a daemon is |
69 | * allowed to block. |
70 | */ |
71 | int (*in_sync)(struct dm_dirty_log *log, region_t region, |
72 | int can_block); |
73 | |
74 | /* |
75 | * Flush the current log state (eg, to disk). This |
76 | * function may block. |
77 | */ |
78 | int (*flush)(struct dm_dirty_log *log); |
79 | |
80 | /* |
81 | * Mark an area as clean or dirty. These functions may |
82 | * block, though for performance reasons blocking should |
83 | * be extremely rare (eg, allocating another chunk of |
84 | * memory for some reason). |
85 | */ |
86 | void (*mark_region)(struct dm_dirty_log *log, region_t region); |
87 | void (*clear_region)(struct dm_dirty_log *log, region_t region); |
88 | |
89 | /* |
90 | * Returns: <0 (error), 0 (no region), 1 (region) |
91 | * |
92 | * The mirrord will need perform recovery on regions of |
93 | * the mirror that are in the NOSYNC state. This |
94 | * function asks the log to tell the caller about the |
95 | * next region that this machine should recover. |
96 | * |
97 | * Do not confuse this function with 'in_sync()', one |
98 | * tells you if an area is synchronised, the other |
99 | * assigns recovery work. |
100 | */ |
101 | int (*get_resync_work)(struct dm_dirty_log *log, region_t *region); |
102 | |
103 | /* |
104 | * This notifies the log that the resync status of a region |
105 | * has changed. It also clears the region from the recovering |
106 | * list (if present). |
107 | */ |
108 | void (*set_region_sync)(struct dm_dirty_log *log, |
109 | region_t region, int in_sync); |
110 | |
111 | /* |
112 | * Returns the number of regions that are in sync. |
113 | */ |
114 | region_t (*get_sync_count)(struct dm_dirty_log *log); |
115 | |
116 | /* |
117 | * Support function for mirror status requests. |
118 | */ |
119 | int (*status)(struct dm_dirty_log *log, status_type_t status_type, |
120 | char *result, unsigned int maxlen); |
121 | |
122 | /* |
123 | * is_remote_recovering is necessary for cluster mirroring. It provides |
124 | * a way to detect recovery on another node, so we aren't writing |
125 | * concurrently. This function is likely to block (when a cluster log |
126 | * is used). |
127 | * |
128 | * Returns: 0, 1 |
129 | */ |
130 | int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region); |
131 | }; |
132 | |
133 | int dm_dirty_log_type_register(struct dm_dirty_log_type *type); |
134 | int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type); |
135 | |
136 | /* |
137 | * Make sure you use these two functions, rather than calling |
138 | * type->constructor/destructor() directly. |
139 | */ |
140 | struct dm_dirty_log *dm_dirty_log_create(const char *type_name, |
141 | struct dm_target *ti, |
142 | int (*flush_callback_fn)(struct dm_target *ti), |
143 | unsigned int argc, char **argv); |
144 | void dm_dirty_log_destroy(struct dm_dirty_log *log); |
145 | |
146 | #endif /* __KERNEL__ */ |
147 | #endif /* _LINUX_DM_DIRTY_LOG_H */ |
148 | |