blob: 4f61bc4c14f6f8a24633fef5a432d8c7537567d8 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
/*
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
*
* This file is released under the GPL.
*/
#ifndef DM_SNAPSHOT_H
#define DM_SNAPSHOT_H
#include <linux/device-mapper.h>
#include "dm-exception-store.h"
#include "dm-bio-list.h"
#include <linux/blkdev.h>
#include <linux/workqueue.h>
struct exception_table {
uint32_t hash_mask;
unsigned hash_shift;
struct list_head *table;
};
#define DM_TRACKED_CHUNK_HASH_SIZE 16
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
struct dm_snapshot {
struct rw_semaphore lock;
struct dm_dev *origin;
/* List of snapshots per Origin */
struct list_head list;
/* You can't use a snapshot if this is 0 (e.g. if full) */
int valid;
/* Origin writes don't trigger exceptions until this is set */
int active;
/* Used for display of table */
char type;
mempool_t *pending_pool;
atomic_t pending_exceptions_count;
struct exception_table pending;
struct exception_table complete;
/*
* pe_lock protects all pending_exception operations and access
* as well as the snapshot_bios list.
*/
spinlock_t pe_lock;
/* The on disk metadata handler */
struct dm_exception_store *store;
struct dm_kcopyd_client *kcopyd_client;
/* Queue of snapshot writes for ksnapd to flush */
struct bio_list queued_bios;
struct work_struct queued_bios_work;
/* Chunks with outstanding reads */
mempool_t *tracked_chunk_pool;
spinlock_t tracked_chunk_lock;
struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
};
static inline sector_t chunk_to_sector(struct dm_exception_store *store,
chunk_t chunk)
{
return chunk << store->chunk_shift;
}
static inline int bdev_equal(struct block_device *lhs, struct block_device *rhs)
{
/*
* There is only ever one instance of a particular block
* device so we can compare pointers safely.
*/
return lhs == rhs;
}
#endif
|
