1 /*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7 #ifndef _LINUX_DM_SPACE_MAP_H
8 #define _LINUX_DM_SPACE_MAP_H
9
10 #include "dm-block-manager.h"
11
12 typedef void (*dm_sm_threshold_fn)(void *context);
13
14 /*
15 * struct dm_space_map keeps a record of how many times each block in a device
16 * is referenced. It needs to be fixed on disk as part of the transaction.
17 */
18 struct dm_space_map {
19 void (*destroy)(struct dm_space_map *sm);
20
21 /*
22 * You must commit before allocating the newly added space.
23 */
24 int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks);
25
26 /*
27 * Extensions do not appear in this count until after commit has
28 * been called.
29 */
30 int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count);
31
32 /*
33 * Space maps must never allocate a block from the previous
34 * transaction, in case we need to rollback. This complicates the
35 * semantics of get_nr_free(), it should return the number of blocks
36 * that are available for allocation _now_. For instance you may
37 * have blocks with a zero reference count that will not be
38 * available for allocation until after the next commit.
39 */
40 int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count);
41
42 int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result);
43 int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b,
44 int *result);
45 int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count);
46
47 int (*commit)(struct dm_space_map *sm);
48
49 int (*inc_blocks)(struct dm_space_map *sm, dm_block_t b, dm_block_t e);
50 int (*dec_blocks)(struct dm_space_map *sm, dm_block_t b, dm_block_t e);
51
52 /*
53 * new_block will increment the returned block.
54 */
55 int (*new_block)(struct dm_space_map *sm, dm_block_t *b);
56
57 /*
58 * The root contains all the information needed to fix the space map.
59 * Generally this info is small, so squirrel it away in a disk block
60 * along with other info.
61 */
62 int (*root_size)(struct dm_space_map *sm, size_t *result);
63 int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);
64
65 /*
66 * You can register one threshold callback which is edge-triggered
67 * when the free space in the space map drops below the threshold.
68 */
69 int (*register_threshold_callback)(struct dm_space_map *sm,
70 dm_block_t threshold,
71 dm_sm_threshold_fn fn,
72 void *context);
73 };
74
75 /*----------------------------------------------------------------*/
76
dm_sm_destroy(struct dm_space_map * sm)77 static inline void dm_sm_destroy(struct dm_space_map *sm)
78 {
79 sm->destroy(sm);
80 }
81
dm_sm_extend(struct dm_space_map * sm,dm_block_t extra_blocks)82 static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
83 {
84 return sm->extend(sm, extra_blocks);
85 }
86
dm_sm_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)87 static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
88 {
89 return sm->get_nr_blocks(sm, count);
90 }
91
dm_sm_get_nr_free(struct dm_space_map * sm,dm_block_t * count)92 static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
93 {
94 return sm->get_nr_free(sm, count);
95 }
96
dm_sm_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)97 static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
98 uint32_t *result)
99 {
100 return sm->get_count(sm, b, result);
101 }
102
dm_sm_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)103 static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
104 dm_block_t b, int *result)
105 {
106 return sm->count_is_more_than_one(sm, b, result);
107 }
108
dm_sm_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)109 static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
110 uint32_t count)
111 {
112 return sm->set_count(sm, b, count);
113 }
114
dm_sm_commit(struct dm_space_map * sm)115 static inline int dm_sm_commit(struct dm_space_map *sm)
116 {
117 return sm->commit(sm);
118 }
119
dm_sm_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)120 static inline int dm_sm_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
121 {
122 return sm->inc_blocks(sm, b, e);
123 }
124
dm_sm_inc_block(struct dm_space_map * sm,dm_block_t b)125 static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
126 {
127 return dm_sm_inc_blocks(sm, b, b + 1);
128 }
129
dm_sm_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)130 static inline int dm_sm_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
131 {
132 return sm->dec_blocks(sm, b, e);
133 }
134
dm_sm_dec_block(struct dm_space_map * sm,dm_block_t b)135 static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
136 {
137 return dm_sm_dec_blocks(sm, b, b + 1);
138 }
139
dm_sm_new_block(struct dm_space_map * sm,dm_block_t * b)140 static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
141 {
142 return sm->new_block(sm, b);
143 }
144
dm_sm_root_size(struct dm_space_map * sm,size_t * result)145 static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
146 {
147 return sm->root_size(sm, result);
148 }
149
dm_sm_copy_root(struct dm_space_map * sm,void * copy_to_here_le,size_t len)150 static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
151 {
152 return sm->copy_root(sm, copy_to_here_le, len);
153 }
154
dm_sm_register_threshold_callback(struct dm_space_map * sm,dm_block_t threshold,dm_sm_threshold_fn fn,void * context)155 static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,
156 dm_block_t threshold,
157 dm_sm_threshold_fn fn,
158 void *context)
159 {
160 if (sm->register_threshold_callback)
161 return sm->register_threshold_callback(sm, threshold, fn, context);
162
163 return -EINVAL;
164 }
165
166
167 #endif /* _LINUX_DM_SPACE_MAP_H */
168