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10#ifndef _LINUX_DM_EXCEPTION_STORE
11#define _LINUX_DM_EXCEPTION_STORE
12
13#include <linux/blkdev.h>
14#include <linux/list_bl.h>
15#include <linux/device-mapper.h>
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20
21typedef sector_t chunk_t;
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29
30struct dm_exception {
31 struct hlist_bl_node hash_list;
32
33 chunk_t old_chunk;
34 chunk_t new_chunk;
35};
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40
41struct dm_exception_store;
42struct dm_exception_store_type {
43 const char *name;
44 struct module *module;
45
46 int (*ctr) (struct dm_exception_store *store, char *options);
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50
51 void (*dtr) (struct dm_exception_store *store);
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57
58 int (*read_metadata) (struct dm_exception_store *store,
59 int (*callback)(void *callback_context,
60 chunk_t old, chunk_t new),
61 void *callback_context);
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65
66 int (*prepare_exception) (struct dm_exception_store *store,
67 struct dm_exception *e);
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71
72 void (*commit_exception) (struct dm_exception_store *store,
73 struct dm_exception *e, int valid,
74 void (*callback) (void *, int success),
75 void *callback_context);
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85 int (*prepare_merge) (struct dm_exception_store *store,
86 chunk_t *last_old_chunk, chunk_t *last_new_chunk);
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92 int (*commit_merge) (struct dm_exception_store *store, int nr_merged);
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97 void (*drop_snapshot) (struct dm_exception_store *store);
98
99 unsigned (*status) (struct dm_exception_store *store,
100 status_type_t status, char *result,
101 unsigned maxlen);
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105
106 void (*usage) (struct dm_exception_store *store,
107 sector_t *total_sectors, sector_t *sectors_allocated,
108 sector_t *metadata_sectors);
109
110
111 struct list_head list;
112};
113
114struct dm_snapshot;
115
116struct dm_exception_store {
117 struct dm_exception_store_type *type;
118 struct dm_snapshot *snap;
119
120
121 unsigned chunk_size;
122 unsigned chunk_mask;
123 unsigned chunk_shift;
124
125 void *context;
126
127 bool userspace_supports_overflow;
128};
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133struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
134struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
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138
139#define DM_CHUNK_CONSECUTIVE_BITS 8
140#define DM_CHUNK_NUMBER_BITS 56
141
142static inline chunk_t dm_chunk_number(chunk_t chunk)
143{
144 return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
145}
146
147static inline unsigned dm_consecutive_chunk_count(struct dm_exception *e)
148{
149 return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
150}
151
152static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
153{
154 e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
155
156 BUG_ON(!dm_consecutive_chunk_count(e));
157}
158
159static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e)
160{
161 BUG_ON(!dm_consecutive_chunk_count(e));
162
163 e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS);
164}
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168
169static inline sector_t get_dev_size(struct block_device *bdev)
170{
171 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
172}
173
174static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
175 sector_t sector)
176{
177 return sector >> store->chunk_shift;
178}
179
180int dm_exception_store_type_register(struct dm_exception_store_type *type);
181int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
182
183int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
184 unsigned chunk_size,
185 char **error);
186
187int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
188 struct dm_snapshot *snap,
189 unsigned *args_used,
190 struct dm_exception_store **store);
191void dm_exception_store_destroy(struct dm_exception_store *store);
192
193int dm_exception_store_init(void);
194void dm_exception_store_exit(void);
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198
199int dm_persistent_snapshot_init(void);
200void dm_persistent_snapshot_exit(void);
201
202int dm_transient_snapshot_init(void);
203void dm_transient_snapshot_exit(void);
204
205#endif
206