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  */
16 struct 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 
66 static inline void dm_sm_destroy(struct dm_space_map *sm)
67 {
68 	sm->destroy(sm);
69 }
70 
71 static 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 
76 static 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 
81 static 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 
86 static 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 
92 static 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 
98 static 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 
104 static inline int dm_sm_commit(struct dm_space_map *sm)
105 {
106 	return sm->commit(sm);
107 }
108 
109 static 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 
114 static 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 
119 static 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 
124 static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
125 {
126 	return sm->root_size(sm, result);
127 }
128 
129 static 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