1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2011 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8 #ifndef _LINUX_DM_SPACE_MAP_H
9 #define _LINUX_DM_SPACE_MAP_H
10
11 #include "dm-block-manager.h"
12
13 typedef void (*dm_sm_threshold_fn)(void *context);
14
15 /*
16 * struct dm_space_map keeps a record of how many times each block in a device
17 * is referenced. It needs to be fixed on disk as part of the transaction.
18 */
19 struct dm_space_map {
20 void (*destroy)(struct dm_space_map *sm);
21
22 /*
23 * You must commit before allocating the newly added space.
24 */
25 int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks);
26
27 /*
28 * Extensions do not appear in this count until after commit has
29 * been called.
30 */
31 int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count);
32
33 /*
34 * Space maps must never allocate a block from the previous
35 * transaction, in case we need to rollback. This complicates the
36 * semantics of get_nr_free(), it should return the number of blocks
37 * that are available for allocation _now_. For instance you may
38 * have blocks with a zero reference count that will not be
39 * available for allocation until after the next commit.
40 */
41 int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count);
42
43 int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result);
44 int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b,
45 int *result);
46 int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count);
47
48 int (*commit)(struct dm_space_map *sm);
49
50 int (*inc_blocks)(struct dm_space_map *sm, dm_block_t b, dm_block_t e);
51 int (*dec_blocks)(struct dm_space_map *sm, dm_block_t b, dm_block_t e);
52
53 /*
54 * new_block will increment the returned block.
55 */
56 int (*new_block)(struct dm_space_map *sm, dm_block_t *b);
57
58 /*
59 * The root contains all the information needed to fix the space map.
60 * Generally this info is small, so squirrel it away in a disk block
61 * along with other info.
62 */
63 int (*root_size)(struct dm_space_map *sm, size_t *result);
64 int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);
65
66 /*
67 * You can register one threshold callback which is edge-triggered
68 * when the free space in the space map drops below the threshold.
69 */
70 int (*register_threshold_callback)(struct dm_space_map *sm,
71 dm_block_t threshold,
72 dm_sm_threshold_fn fn,
73 void *context);
74 };
75
76 /*----------------------------------------------------------------*/
77
dm_sm_destroy(struct dm_space_map * sm)78 static inline void dm_sm_destroy(struct dm_space_map *sm)
79 {
80 if (sm)
81 sm->destroy(sm);
82 }
83
dm_sm_extend(struct dm_space_map * sm,dm_block_t extra_blocks)84 static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
85 {
86 return sm->extend(sm, extra_blocks);
87 }
88
dm_sm_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)89 static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
90 {
91 return sm->get_nr_blocks(sm, count);
92 }
93
dm_sm_get_nr_free(struct dm_space_map * sm,dm_block_t * count)94 static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
95 {
96 return sm->get_nr_free(sm, count);
97 }
98
dm_sm_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)99 static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
100 uint32_t *result)
101 {
102 return sm->get_count(sm, b, result);
103 }
104
dm_sm_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)105 static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
106 dm_block_t b, int *result)
107 {
108 return sm->count_is_more_than_one(sm, b, result);
109 }
110
dm_sm_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)111 static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
112 uint32_t count)
113 {
114 return sm->set_count(sm, b, count);
115 }
116
dm_sm_commit(struct dm_space_map * sm)117 static inline int dm_sm_commit(struct dm_space_map *sm)
118 {
119 return sm->commit(sm);
120 }
121
dm_sm_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)122 static inline int dm_sm_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
123 {
124 return sm->inc_blocks(sm, b, e);
125 }
126
dm_sm_inc_block(struct dm_space_map * sm,dm_block_t b)127 static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
128 {
129 return dm_sm_inc_blocks(sm, b, b + 1);
130 }
131
dm_sm_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)132 static inline int dm_sm_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
133 {
134 return sm->dec_blocks(sm, b, e);
135 }
136
dm_sm_dec_block(struct dm_space_map * sm,dm_block_t b)137 static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
138 {
139 return dm_sm_dec_blocks(sm, b, b + 1);
140 }
141
dm_sm_new_block(struct dm_space_map * sm,dm_block_t * b)142 static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
143 {
144 return sm->new_block(sm, b);
145 }
146
dm_sm_root_size(struct dm_space_map * sm,size_t * result)147 static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
148 {
149 return sm->root_size(sm, result);
150 }
151
dm_sm_copy_root(struct dm_space_map * sm,void * copy_to_here_le,size_t len)152 static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
153 {
154 return sm->copy_root(sm, copy_to_here_le, len);
155 }
156
dm_sm_register_threshold_callback(struct dm_space_map * sm,dm_block_t threshold,dm_sm_threshold_fn fn,void * context)157 static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,
158 dm_block_t threshold,
159 dm_sm_threshold_fn fn,
160 void *context)
161 {
162 if (sm->register_threshold_callback)
163 return sm->register_threshold_callback(sm, threshold, fn, context);
164
165 return -EINVAL;
166 }
167
168
169 #endif /* _LINUX_DM_SPACE_MAP_H */
170