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
161
162
163
164
165
166
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <asm/unaligned.h>
#include "ctree.h"
static bool check_setget_bounds(const struct extent_buffer *eb,
const void *ptr, unsigned off, int size)
{
const unsigned long member_offset = (unsigned long)ptr + off;
if (unlikely(member_offset + size > eb->len)) {
btrfs_warn(eb->fs_info,
"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
(member_offset > eb->len ? "start" : "end"),
(unsigned long)ptr, eb->start, member_offset, size);
return false;
}
return true;
}
/*
* Macro templates that define helpers to read/write extent buffer data of a
* given size, that are also used via ctree.h for access to item members by
* specialized helpers.
*
* Generic helpers:
* - btrfs_set_8 (for 8/16/32/64)
* - btrfs_get_8 (for 8/16/32/64)
*
* Generic helpers with a token (cached address of the most recently accessed
* page):
* - btrfs_set_token_8 (for 8/16/32/64)
* - btrfs_get_token_8 (for 8/16/32/64)
*
* The set/get functions handle data spanning two pages transparently, in case
* metadata block size is larger than page. Every pointer to metadata items is
* an offset into the extent buffer page array, cast to a specific type. This
* gives us all the type checking.
*
* The extent buffer pages stored in the array pages do not form a contiguous
* phyusical range, but the API functions assume the linear offset to the range
* from 0 to metadata node size.
*/
#define DEFINE_BTRFS_SETGET_BITS(bits) \
u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \
const void *ptr, unsigned long off) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long idx = get_eb_page_index(member_offset); \
const unsigned long oip = get_eb_offset_in_page(token->eb, \
member_offset); \
const int size = sizeof(u##bits); \
u8 lebytes[sizeof(u##bits)]; \
const int part = PAGE_SIZE - oip; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + PAGE_SIZE) { \
return get_unaligned_le##bits(token->kaddr + oip); \
} \
token->kaddr = page_address(token->eb->pages[idx]); \
token->offset = idx << PAGE_SHIFT; \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE ) \
return get_unaligned_le##bits(token->kaddr + oip); \
\
memcpy(lebytes, token->kaddr + oip, part); \
token->kaddr = page_address(token->eb->pages[idx + 1]); \
token->offset = (idx + 1) << PAGE_SHIFT; \
memcpy(lebytes + part, token->kaddr, size - part); \
return get_unaligned_le##bits(lebytes); \
} \
u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
const void *ptr, unsigned long off) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
const unsigned long idx = get_eb_page_index(member_offset); \
char *kaddr = page_address(eb->pages[idx]); \
const int size = sizeof(u##bits); \
const int part = PAGE_SIZE - oip; \
u8 lebytes[sizeof(u##bits)]; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) \
return get_unaligned_le##bits(kaddr + oip); \
\
memcpy(lebytes, kaddr + oip, part); \
kaddr = page_address(eb->pages[idx + 1]); \
memcpy(lebytes + part, kaddr, size - part); \
return get_unaligned_le##bits(lebytes); \
} \
void btrfs_set_token_##bits(struct btrfs_map_token *token, \
const void *ptr, unsigned long off, \
u##bits val) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long idx = get_eb_page_index(member_offset); \
const unsigned long oip = get_eb_offset_in_page(token->eb, \
member_offset); \
const int size = sizeof(u##bits); \
u8 lebytes[sizeof(u##bits)]; \
const int part = PAGE_SIZE - oip; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + PAGE_SIZE) { \
put_unaligned_le##bits(val, token->kaddr + oip); \
return; \
} \
token->kaddr = page_address(token->eb->pages[idx]); \
token->offset = idx << PAGE_SHIFT; \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
put_unaligned_le##bits(val, token->kaddr + oip); \
return; \
} \
put_unaligned_le##bits(val, lebytes); \
memcpy(token->kaddr + oip, lebytes, part); \
token->kaddr = page_address(token->eb->pages[idx + 1]); \
token->offset = (idx + 1) << PAGE_SHIFT; \
memcpy(token->kaddr, lebytes + part, size - part); \
} \
void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
const unsigned long idx = get_eb_page_index(member_offset); \
char *kaddr = page_address(eb->pages[idx]); \
const int size = sizeof(u##bits); \
const int part = PAGE_SIZE - oip; \
u8 lebytes[sizeof(u##bits)]; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \
put_unaligned_le##bits(val, kaddr + oip); \
return; \
} \
\
put_unaligned_le##bits(val, lebytes); \
memcpy(kaddr + oip, lebytes, part); \
kaddr = page_address(eb->pages[idx + 1]); \
memcpy(kaddr, lebytes + part, size - part); \
}
DEFINE_BTRFS_SETGET_BITS(8)
DEFINE_BTRFS_SETGET_BITS(16)
DEFINE_BTRFS_SETGET_BITS(32)
DEFINE_BTRFS_SETGET_BITS(64)
void btrfs_node_key(const struct extent_buffer *eb,
struct btrfs_disk_key *disk_key, int nr)
{
unsigned long ptr = btrfs_node_key_ptr_offset(nr);
read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
struct btrfs_key_ptr, key, disk_key);
}
|
