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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <asm/unaligned.h>
7
8#include "ctree.h"
9
10static inline u8 get_unaligned_le8(const void *p)
11{
12 return *(u8 *)p;
13}
14
15static inline void put_unaligned_le8(u8 val, void *p)
16{
17 *(u8 *)p = val;
18}
19
20/*
21 * this is some deeply nasty code.
22 *
23 * The end result is that anyone who #includes ctree.h gets a
24 * declaration for the btrfs_set_foo functions and btrfs_foo functions,
25 * which are wrappers of btrfs_set_token_#bits functions and
26 * btrfs_get_token_#bits functions, which are defined in this file.
27 *
28 * These setget functions do all the extent_buffer related mapping
29 * required to efficiently read and write specific fields in the extent
30 * buffers. Every pointer to metadata items in btrfs is really just
31 * an unsigned long offset into the extent buffer which has been
32 * cast to a specific type. This gives us all the gcc type checking.
33 *
34 * The extent buffer api is used to do the page spanning work required to
35 * have a metadata blocksize different from the page size.
36 *
37 * There are 2 variants defined, one with a token pointer and one without.
38 */
39
40#define DEFINE_BTRFS_SETGET_BITS(bits) \
41u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \
42 const void *ptr, unsigned long off, \
43 struct btrfs_map_token *token) \
44{ \
45 unsigned long part_offset = (unsigned long)ptr; \
46 unsigned long offset = part_offset + off; \
47 void *p; \
48 int err; \
49 char *kaddr; \
50 unsigned long map_start; \
51 unsigned long map_len; \
52 int size = sizeof(u##bits); \
53 u##bits res; \
54 \
55 ASSERT(token); \
56 ASSERT(token->eb == eb); \
57 \
58 if (token->kaddr && token->offset <= offset && \
59 (token->offset + PAGE_SIZE >= offset + size)) { \
60 kaddr = token->kaddr; \
61 p = kaddr + part_offset - token->offset; \
62 res = get_unaligned_le##bits(p + off); \
63 return res; \
64 } \
65 err = map_private_extent_buffer(eb, offset, size, \
66 &kaddr, &map_start, &map_len); \
67 if (err) { \
68 __le##bits leres; \
69 \
70 read_extent_buffer(eb, &leres, offset, size); \
71 return le##bits##_to_cpu(leres); \
72 } \
73 p = kaddr + part_offset - map_start; \
74 res = get_unaligned_le##bits(p + off); \
75 token->kaddr = kaddr; \
76 token->offset = map_start; \
77 return res; \
78} \
79u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
80 const void *ptr, unsigned long off) \
81{ \
82 unsigned long part_offset = (unsigned long)ptr; \
83 unsigned long offset = part_offset + off; \
84 void *p; \
85 int err; \
86 char *kaddr; \
87 unsigned long map_start; \
88 unsigned long map_len; \
89 int size = sizeof(u##bits); \
90 u##bits res; \
91 \
92 err = map_private_extent_buffer(eb, offset, size, \
93 &kaddr, &map_start, &map_len); \
94 if (err) { \
95 __le##bits leres; \
96 \
97 read_extent_buffer(eb, &leres, offset, size); \
98 return le##bits##_to_cpu(leres); \
99 } \
100 p = kaddr + part_offset - map_start; \
101 res = get_unaligned_le##bits(p + off); \
102 return res; \
103} \
104void btrfs_set_token_##bits(struct extent_buffer *eb, \
105 const void *ptr, unsigned long off, \
106 u##bits val, \
107 struct btrfs_map_token *token) \
108{ \
109 unsigned long part_offset = (unsigned long)ptr; \
110 unsigned long offset = part_offset + off; \
111 void *p; \
112 int err; \
113 char *kaddr; \
114 unsigned long map_start; \
115 unsigned long map_len; \
116 int size = sizeof(u##bits); \
117 \
118 ASSERT(token); \
119 ASSERT(token->eb == eb); \
120 \
121 if (token->kaddr && token->offset <= offset && \
122 (token->offset + PAGE_SIZE >= offset + size)) { \
123 kaddr = token->kaddr; \
124 p = kaddr + part_offset - token->offset; \
125 put_unaligned_le##bits(val, p + off); \
126 return; \
127 } \
128 err = map_private_extent_buffer(eb, offset, size, \
129 &kaddr, &map_start, &map_len); \
130 if (err) { \
131 __le##bits val2; \
132 \
133 val2 = cpu_to_le##bits(val); \
134 write_extent_buffer(eb, &val2, offset, size); \
135 return; \
136 } \
137 p = kaddr + part_offset - map_start; \
138 put_unaligned_le##bits(val, p + off); \
139 token->kaddr = kaddr; \
140 token->offset = map_start; \
141} \
142void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
143 unsigned long off, u##bits val) \
144{ \
145 unsigned long part_offset = (unsigned long)ptr; \
146 unsigned long offset = part_offset + off; \
147 void *p; \
148 int err; \
149 char *kaddr; \
150 unsigned long map_start; \
151 unsigned long map_len; \
152 int size = sizeof(u##bits); \
153 \
154 err = map_private_extent_buffer(eb, offset, size, \
155 &kaddr, &map_start, &map_len); \
156 if (err) { \
157 __le##bits val2; \
158 \
159 val2 = cpu_to_le##bits(val); \
160 write_extent_buffer(eb, &val2, offset, size); \
161 return; \
162 } \
163 p = kaddr + part_offset - map_start; \
164 put_unaligned_le##bits(val, p + off); \
165}
166
167DEFINE_BTRFS_SETGET_BITS(8)
168DEFINE_BTRFS_SETGET_BITS(16)
169DEFINE_BTRFS_SETGET_BITS(32)
170DEFINE_BTRFS_SETGET_BITS(64)
171
172void btrfs_node_key(const struct extent_buffer *eb,
173 struct btrfs_disk_key *disk_key, int nr)
174{
175 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
176 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
177 struct btrfs_key_ptr, key, disk_key);
178}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/highmem.h>
20#include <asm/unaligned.h>
21
22#include "ctree.h"
23
24static inline u8 get_unaligned_le8(const void *p)
25{
26 return *(u8 *)p;
27}
28
29static inline void put_unaligned_le8(u8 val, void *p)
30{
31 *(u8 *)p = val;
32}
33
34/*
35 * this is some deeply nasty code.
36 *
37 * The end result is that anyone who #includes ctree.h gets a
38 * declaration for the btrfs_set_foo functions and btrfs_foo functions,
39 * which are wappers of btrfs_set_token_#bits functions and
40 * btrfs_get_token_#bits functions, which are defined in this file.
41 *
42 * These setget functions do all the extent_buffer related mapping
43 * required to efficiently read and write specific fields in the extent
44 * buffers. Every pointer to metadata items in btrfs is really just
45 * an unsigned long offset into the extent buffer which has been
46 * cast to a specific type. This gives us all the gcc type checking.
47 *
48 * The extent buffer api is used to do the page spanning work required to
49 * have a metadata blocksize different from the page size.
50 */
51
52#define DEFINE_BTRFS_SETGET_BITS(bits) \
53u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr, \
54 unsigned long off, \
55 struct btrfs_map_token *token) \
56{ \
57 unsigned long part_offset = (unsigned long)ptr; \
58 unsigned long offset = part_offset + off; \
59 void *p; \
60 int err; \
61 char *kaddr; \
62 unsigned long map_start; \
63 unsigned long map_len; \
64 int size = sizeof(u##bits); \
65 u##bits res; \
66 \
67 if (token && token->kaddr && token->offset <= offset && \
68 token->eb == eb && \
69 (token->offset + PAGE_CACHE_SIZE >= offset + size)) { \
70 kaddr = token->kaddr; \
71 p = kaddr + part_offset - token->offset; \
72 res = get_unaligned_le##bits(p + off); \
73 return res; \
74 } \
75 err = map_private_extent_buffer(eb, offset, size, \
76 &kaddr, &map_start, &map_len); \
77 if (err) { \
78 __le##bits leres; \
79 \
80 read_extent_buffer(eb, &leres, offset, size); \
81 return le##bits##_to_cpu(leres); \
82 } \
83 p = kaddr + part_offset - map_start; \
84 res = get_unaligned_le##bits(p + off); \
85 if (token) { \
86 token->kaddr = kaddr; \
87 token->offset = map_start; \
88 token->eb = eb; \
89 } \
90 return res; \
91} \
92void btrfs_set_token_##bits(struct extent_buffer *eb, \
93 void *ptr, unsigned long off, u##bits val, \
94 struct btrfs_map_token *token) \
95{ \
96 unsigned long part_offset = (unsigned long)ptr; \
97 unsigned long offset = part_offset + off; \
98 void *p; \
99 int err; \
100 char *kaddr; \
101 unsigned long map_start; \
102 unsigned long map_len; \
103 int size = sizeof(u##bits); \
104 \
105 if (token && token->kaddr && token->offset <= offset && \
106 token->eb == eb && \
107 (token->offset + PAGE_CACHE_SIZE >= offset + size)) { \
108 kaddr = token->kaddr; \
109 p = kaddr + part_offset - token->offset; \
110 put_unaligned_le##bits(val, p + off); \
111 return; \
112 } \
113 err = map_private_extent_buffer(eb, offset, size, \
114 &kaddr, &map_start, &map_len); \
115 if (err) { \
116 __le##bits val2; \
117 \
118 val2 = cpu_to_le##bits(val); \
119 write_extent_buffer(eb, &val2, offset, size); \
120 return; \
121 } \
122 p = kaddr + part_offset - map_start; \
123 put_unaligned_le##bits(val, p + off); \
124 if (token) { \
125 token->kaddr = kaddr; \
126 token->offset = map_start; \
127 token->eb = eb; \
128 } \
129}
130
131DEFINE_BTRFS_SETGET_BITS(8)
132DEFINE_BTRFS_SETGET_BITS(16)
133DEFINE_BTRFS_SETGET_BITS(32)
134DEFINE_BTRFS_SETGET_BITS(64)
135
136void btrfs_node_key(struct extent_buffer *eb,
137 struct btrfs_disk_key *disk_key, int nr)
138{
139 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
140 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
141 struct btrfs_key_ptr, key, disk_key);
142}