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-rw-r--r--drivers/md/dm-exception-store.c1
-rw-r--r--drivers/md/dm-exception-store.h131
-rw-r--r--drivers/md/dm-snap.c1
-rw-r--r--drivers/md/dm-snap.h121
4 files changed, 134 insertions, 120 deletions
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 01590f3e0009..ef152e600cb6 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -7,6 +7,7 @@
7 * This file is released under the GPL. 7 * This file is released under the GPL.
8 */ 8 */
9 9
10#include "dm-exception-store.h"
10#include "dm-snap.h" 11#include "dm-snap.h"
11 12
12#include <linux/mm.h> 13#include <linux/mm.h>
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
new file mode 100644
index 000000000000..d75f775562e5
--- /dev/null
+++ b/drivers/md/dm-exception-store.h
@@ -0,0 +1,131 @@
1/*
2 * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
4 *
5 * Device-mapper snapshot exception store.
6 *
7 * This file is released under the GPL.
8 */
9
10#ifndef _LINUX_DM_EXCEPTION_STORE
11#define _LINUX_DM_EXCEPTION_STORE
12
13#include <linux/blkdev.h>
14
15/*
16 * The snapshot code deals with largish chunks of the disk at a
17 * time. Typically 32k - 512k.
18 */
19typedef sector_t chunk_t;
20
21/*
22 * An exception is used where an old chunk of data has been
23 * replaced by a new one.
24 * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
25 * of chunks that follow contiguously. Remaining bits hold the number of the
26 * chunk within the device.
27 */
28struct dm_snap_exception {
29 struct list_head hash_list;
30
31 chunk_t old_chunk;
32 chunk_t new_chunk;
33};
34
35/*
36 * Abstraction to handle the meta/layout of exception stores (the
37 * COW device).
38 */
39struct exception_store {
40 /*
41 * Destroys this object when you've finished with it.
42 */
43 void (*destroy) (struct exception_store *store);
44
45 /*
46 * The target shouldn't read the COW device until this is
47 * called.
48 */
49 int (*read_metadata) (struct exception_store *store);
50
51 /*
52 * Find somewhere to store the next exception.
53 */
54 int (*prepare_exception) (struct exception_store *store,
55 struct dm_snap_exception *e);
56
57 /*
58 * Update the metadata with this exception.
59 */
60 void (*commit_exception) (struct exception_store *store,
61 struct dm_snap_exception *e,
62 void (*callback) (void *, int success),
63 void *callback_context);
64
65 /*
66 * The snapshot is invalid, note this in the metadata.
67 */
68 void (*drop_snapshot) (struct exception_store *store);
69
70 /*
71 * Return how full the snapshot is.
72 */
73 void (*fraction_full) (struct exception_store *store,
74 sector_t *numerator,
75 sector_t *denominator);
76
77 struct dm_snapshot *snap;
78 void *context;
79};
80
81/*
82 * Funtions to manipulate consecutive chunks
83 */
84# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
85# define DM_CHUNK_CONSECUTIVE_BITS 8
86# define DM_CHUNK_NUMBER_BITS 56
87
88static inline chunk_t dm_chunk_number(chunk_t chunk)
89{
90 return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
91}
92
93static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
94{
95 return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
96}
97
98static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
99{
100 e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
101
102 BUG_ON(!dm_consecutive_chunk_count(e));
103}
104
105# else
106# define DM_CHUNK_CONSECUTIVE_BITS 0
107
108static inline chunk_t dm_chunk_number(chunk_t chunk)
109{
110 return chunk;
111}
112
113static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
114{
115 return 0;
116}
117
118static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
119{
120}
121
122# endif
123
124/*
125 * Two exception store implementations.
126 */
127int dm_create_persistent(struct exception_store *store);
128
129int dm_create_transient(struct exception_store *store);
130
131#endif /* _LINUX_DM_EXCEPTION_STORE */
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a8005b43a06b..81f03a0e7838 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -21,6 +21,7 @@
21#include <linux/log2.h> 21#include <linux/log2.h>
22#include <linux/dm-kcopyd.h> 22#include <linux/dm-kcopyd.h>
23 23
24#include "dm-exception-store.h"
24#include "dm-snap.h" 25#include "dm-snap.h"
25#include "dm-bio-list.h" 26#include "dm-bio-list.h"
26 27
diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index 99c0106ede2d..6e4beaf89f6c 100644
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -1,6 +1,4 @@
1/* 1/*
2 * dm-snapshot.c
3 *
4 * Copyright (C) 2001-2002 Sistina Software (UK) Limited. 2 * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
5 * 3 *
6 * This file is released under the GPL. 4 * This file is released under the GPL.
@@ -10,6 +8,7 @@
10#define DM_SNAPSHOT_H 8#define DM_SNAPSHOT_H
11 9
12#include <linux/device-mapper.h> 10#include <linux/device-mapper.h>
11#include "dm-exception-store.h"
13#include "dm-bio-list.h" 12#include "dm-bio-list.h"
14#include <linux/blkdev.h> 13#include <linux/blkdev.h>
15#include <linux/workqueue.h> 14#include <linux/workqueue.h>
@@ -20,116 +19,6 @@ struct exception_table {
20 struct list_head *table; 19 struct list_head *table;
21}; 20};
22 21
23/*
24 * The snapshot code deals with largish chunks of the disk at a
25 * time. Typically 32k - 512k.
26 */
27typedef sector_t chunk_t;
28
29/*
30 * An exception is used where an old chunk of data has been
31 * replaced by a new one.
32 * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
33 * of chunks that follow contiguously. Remaining bits hold the number of the
34 * chunk within the device.
35 */
36struct dm_snap_exception {
37 struct list_head hash_list;
38
39 chunk_t old_chunk;
40 chunk_t new_chunk;
41};
42
43/*
44 * Funtions to manipulate consecutive chunks
45 */
46# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
47# define DM_CHUNK_CONSECUTIVE_BITS 8
48# define DM_CHUNK_NUMBER_BITS 56
49
50static inline chunk_t dm_chunk_number(chunk_t chunk)
51{
52 return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
53}
54
55static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
56{
57 return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
58}
59
60static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
61{
62 e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
63
64 BUG_ON(!dm_consecutive_chunk_count(e));
65}
66
67# else
68# define DM_CHUNK_CONSECUTIVE_BITS 0
69
70static inline chunk_t dm_chunk_number(chunk_t chunk)
71{
72 return chunk;
73}
74
75static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
76{
77 return 0;
78}
79
80static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
81{
82}
83
84# endif
85
86/*
87 * Abstraction to handle the meta/layout of exception stores (the
88 * COW device).
89 */
90struct exception_store {
91
92 /*
93 * Destroys this object when you've finished with it.
94 */
95 void (*destroy) (struct exception_store *store);
96
97 /*
98 * The target shouldn't read the COW device until this is
99 * called.
100 */
101 int (*read_metadata) (struct exception_store *store);
102
103 /*
104 * Find somewhere to store the next exception.
105 */
106 int (*prepare_exception) (struct exception_store *store,
107 struct dm_snap_exception *e);
108
109 /*
110 * Update the metadata with this exception.
111 */
112 void (*commit_exception) (struct exception_store *store,
113 struct dm_snap_exception *e,
114 void (*callback) (void *, int success),
115 void *callback_context);
116
117 /*
118 * The snapshot is invalid, note this in the metadata.
119 */
120 void (*drop_snapshot) (struct exception_store *store);
121
122 /*
123 * Return how full the snapshot is.
124 */
125 void (*fraction_full) (struct exception_store *store,
126 sector_t *numerator,
127 sector_t *denominator);
128
129 struct dm_snapshot *snap;
130 void *context;
131};
132
133#define DM_TRACKED_CHUNK_HASH_SIZE 16 22#define DM_TRACKED_CHUNK_HASH_SIZE 16
134#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \ 23#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
135 (DM_TRACKED_CHUNK_HASH_SIZE - 1)) 24 (DM_TRACKED_CHUNK_HASH_SIZE - 1))
@@ -193,14 +82,6 @@ struct dm_snapshot {
193int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new); 82int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
194 83
195/* 84/*
196 * Constructor and destructor for the default persistent
197 * store.
198 */
199int dm_create_persistent(struct exception_store *store);
200
201int dm_create_transient(struct exception_store *store);
202
203/*
204 * Return the number of sectors in the device. 85 * Return the number of sectors in the device.
205 */ 86 */
206static inline sector_t get_dev_size(struct block_device *bdev) 87static inline sector_t get_dev_size(struct block_device *bdev)
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-25 13:21:33 -0400