Root/drivers/md/persistent-data/dm-space-map.h

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/*
13 * struct dm_space_map keeps a record of how many times each block in a device
14 * is referenced. It needs to be fixed on disk as part of the transaction.
15 */
16struct dm_space_map {
17    void (*destroy)(struct dm_space_map *sm);
18
19    /*
20     * You must commit before allocating the newly added space.
21     */
22    int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks);
23
24    /*
25     * Extensions do not appear in this count until after commit has
26     * been called.
27     */
28    int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count);
29
30    /*
31     * Space maps must never allocate a block from the previous
32     * transaction, in case we need to rollback. This complicates the
33     * semantics of get_nr_free(), it should return the number of blocks
34     * that are available for allocation _now_. For instance you may
35     * have blocks with a zero reference count that will not be
36     * available for allocation until after the next commit.
37     */
38    int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count);
39
40    int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result);
41    int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b,
42                      int *result);
43    int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count);
44
45    int (*commit)(struct dm_space_map *sm);
46
47    int (*inc_block)(struct dm_space_map *sm, dm_block_t b);
48    int (*dec_block)(struct dm_space_map *sm, dm_block_t b);
49
50    /*
51     * new_block will increment the returned block.
52     */
53    int (*new_block)(struct dm_space_map *sm, dm_block_t *b);
54
55    /*
56     * The root contains all the information needed to fix the space map.
57     * Generally this info is small, so squirrel it away in a disk block
58     * along with other info.
59     */
60    int (*root_size)(struct dm_space_map *sm, size_t *result);
61    int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);
62};
63
64/*----------------------------------------------------------------*/
65
66static inline void dm_sm_destroy(struct dm_space_map *sm)
67{
68    sm->destroy(sm);
69}
70
71static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
72{
73    return sm->extend(sm, extra_blocks);
74}
75
76static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
77{
78    return sm->get_nr_blocks(sm, count);
79}
80
81static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
82{
83    return sm->get_nr_free(sm, count);
84}
85
86static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
87                  uint32_t *result)
88{
89    return sm->get_count(sm, b, result);
90}
91
92static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
93                           dm_block_t b, int *result)
94{
95    return sm->count_is_more_than_one(sm, b, result);
96}
97
98static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
99                  uint32_t count)
100{
101    return sm->set_count(sm, b, count);
102}
103
104static inline int dm_sm_commit(struct dm_space_map *sm)
105{
106    return sm->commit(sm);
107}
108
109static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
110{
111    return sm->inc_block(sm, b);
112}
113
114static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
115{
116    return sm->dec_block(sm, b);
117}
118
119static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
120{
121    return sm->new_block(sm, b);
122}
123
124static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
125{
126    return sm->root_size(sm, result);
127}
128
129static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
130{
131    return sm->copy_root(sm, copy_to_here_le, len);
132}
133
134#endif /* _LINUX_DM_SPACE_MAP_H */
135

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