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 78 static inline void dm_sm_destroy(struct dm_space_map *sm) 79 { 80 sm->destroy(sm); 81 } 82 83 static 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 88 static 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 93 static 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 98 static 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 } 103 104 static 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 } 109 110 static 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 } 115 116 static inline int dm_sm_commit(struct dm_space_map *sm) 117 { 118 return sm->commit(sm); 119 } 120 121 static 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 } 125 126 static 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 } 130 131 static 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 } 135 136 static 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 } 140 141 static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b) 142 { 143 return sm->new_block(sm, b); 144 } 145 146 static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result) 147 { 148 return sm->root_size(sm, result); 149 } 150 151 static 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 } 155 156 static 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 */ 169