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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#ifndef DM_BTREE_INTERNAL_H
#define DM_BTREE_INTERNAL_H
#include "dm-btree.h"
/*----------------------------------------------------------------*/
/*
* We'll need 2 accessor functions for n->csum and n->blocknr
* to support dm-btree-spine.c in that case.
*/
enum node_flags {
INTERNAL_NODE = 1,
LEAF_NODE = 1 << 1
};
/*
* Every btree node begins with this structure. Make sure it's a multiple
* of 8-bytes in size, otherwise the 64bit keys will be mis-aligned.
*/
struct node_header {
__le32 csum;
__le32 flags;
__le64 blocknr; /* Block this node is supposed to live in. */
__le32 nr_entries;
__le32 max_entries;
__le32 value_size;
__le32 padding;
} __attribute__((packed, aligned(8)));
struct btree_node {
struct node_header header;
__le64 keys[];
} __attribute__((packed, aligned(8)));
/*
* Locks a block using the btree node validator.
*/
int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
struct dm_block **result);
void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
struct dm_btree_value_type *vt);
int new_block(struct dm_btree_info *info, struct dm_block **result);
void unlock_block(struct dm_btree_info *info, struct dm_block *b);
/*
* Spines keep track of the rolling locks. There are 2 variants, read-only
* and one that uses shadowing. These are separate structs to allow the
* type checker to spot misuse, for example accidentally calling read_lock
* on a shadow spine.
*/
struct ro_spine {
struct dm_btree_info *info;
int count;
struct dm_block *nodes[2];
};
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
void exit_ro_spine(struct ro_spine *s);
int ro_step(struct ro_spine *s, dm_block_t new_child);
void ro_pop(struct ro_spine *s);
struct btree_node *ro_node(struct ro_spine *s);
struct shadow_spine {
struct dm_btree_info *info;
int count;
struct dm_block *nodes[2];
dm_block_t root;
};
void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
void exit_shadow_spine(struct shadow_spine *s);
int shadow_step(struct shadow_spine *s, dm_block_t b,
struct dm_btree_value_type *vt);
/*
* The spine must have at least one entry before calling this.
*/
struct dm_block *shadow_current(struct shadow_spine *s);
/*
* The spine must have at least two entries before calling this.
*/
struct dm_block *shadow_parent(struct shadow_spine *s);
int shadow_has_parent(struct shadow_spine *s);
dm_block_t shadow_root(struct shadow_spine *s);
/*
* Some inlines.
*/
static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
{
return n->keys + index;
}
static inline void *value_base(struct btree_node *n)
{
return &n->keys[le32_to_cpu(n->header.max_entries)];
}
static inline void *value_ptr(struct btree_node *n, uint32_t index)
{
uint32_t value_size = le32_to_cpu(n->header.value_size);
return value_base(n) + (value_size * index);
}
/*
* Assumes the values are suitably-aligned and converts to core format.
*/
static inline uint64_t value64(struct btree_node *n, uint32_t index)
{
__le64 *values_le = value_base(n);
return le64_to_cpu(values_le[index]);
}
/*
* Searching for a key within a single node.
*/
int lower_bound(struct btree_node *n, uint64_t key);
extern struct dm_block_validator btree_node_validator;
/*
* Value type for upper levels of multi-level btrees.
*/
extern void init_le64_type(struct dm_transaction_manager *tm,
struct dm_btree_value_type *vt);
/*
* This returns a shadowed btree leaf that you may modify. In practise
* this means overwrites only, since an insert could cause a node to
* be split. Useful if you need access to the old value to calculate the
* new one.
*
* This only works with single level btrees. The given key must be present in
* the tree, otherwise -EINVAL will be returned.
*/
int btree_get_overwrite_leaf(struct dm_btree_info *info, dm_block_t root,
uint64_t key, int *index,
dm_block_t *new_root, struct dm_block **leaf);
#endif /* DM_BTREE_INTERNAL_H */
|
