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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
13typedef 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 */
19struct 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
78static inline void dm_sm_destroy(struct dm_space_map *sm)
79{
80 sm->destroy(sm);
81}
82
83static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
84{
85 return sm->extend(sm, extra_blocks);
86}
87
88static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
89{
90 return sm->get_nr_blocks(sm, count);
91}
92
93static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
94{
95 return sm->get_nr_free(sm, count);
96}
97
98static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
99 uint32_t *result)
100{
101 return sm->get_count(sm, b, result);
102}
103
104static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
105 dm_block_t b, int *result)
106{
107 return sm->count_is_more_than_one(sm, b, result);
108}
109
110static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
111 uint32_t count)
112{
113 return sm->set_count(sm, b, count);
114}
115
116static inline int dm_sm_commit(struct dm_space_map *sm)
117{
118 return sm->commit(sm);
119}
120
121static inline int dm_sm_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
122{
123 return sm->inc_blocks(sm, b, e);
124}
125
126static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
127{
128 return dm_sm_inc_blocks(sm, b, b + 1);
129}
130
131static inline int dm_sm_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
132{
133 return sm->dec_blocks(sm, b, e);
134}
135
136static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
137{
138 return dm_sm_dec_blocks(sm, b, b + 1);
139}
140
141static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
142{
143 return sm->new_block(sm, b);
144}
145
146static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
147{
148 return sm->root_size(sm, result);
149}
150
151static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
152{
153 return sm->copy_root(sm, copy_to_here_le, len);
154}
155
156static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,
157 dm_block_t threshold,
158 dm_sm_threshold_fn fn,
159 void *context)
160{
161 if (sm->register_threshold_callback)
162 return sm->register_threshold_callback(sm, threshold, fn, context);
163
164 return -EINVAL;
165}
166
167
168#endif /* _LINUX_DM_SPACE_MAP_H */