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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/highmem.h>
7#include <asm/unaligned.h>
8
9#include "ctree.h"
10
11static inline u8 get_unaligned_le8(const void *p)
12{
13 return *(u8 *)p;
14}
15
16static inline void put_unaligned_le8(u8 val, void *p)
17{
18 *(u8 *)p = val;
19}
20
21/*
22 * this is some deeply nasty code.
23 *
24 * The end result is that anyone who #includes ctree.h gets a
25 * declaration for the btrfs_set_foo functions and btrfs_foo functions,
26 * which are wrappers of btrfs_set_token_#bits functions and
27 * btrfs_get_token_#bits functions, which are defined in this file.
28 *
29 * These setget functions do all the extent_buffer related mapping
30 * required to efficiently read and write specific fields in the extent
31 * buffers. Every pointer to metadata items in btrfs is really just
32 * an unsigned long offset into the extent buffer which has been
33 * cast to a specific type. This gives us all the gcc type checking.
34 *
35 * The extent buffer api is used to do the page spanning work required to
36 * have a metadata blocksize different from the page size.
37 */
38
39#define DEFINE_BTRFS_SETGET_BITS(bits) \
40u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \
41 const void *ptr, unsigned long off, \
42 struct btrfs_map_token *token) \
43{ \
44 unsigned long part_offset = (unsigned long)ptr; \
45 unsigned long offset = part_offset + off; \
46 void *p; \
47 int err; \
48 char *kaddr; \
49 unsigned long map_start; \
50 unsigned long map_len; \
51 int size = sizeof(u##bits); \
52 u##bits res; \
53 \
54 if (token && token->kaddr && token->offset <= offset && \
55 token->eb == eb && \
56 (token->offset + PAGE_SIZE >= offset + size)) { \
57 kaddr = token->kaddr; \
58 p = kaddr + part_offset - token->offset; \
59 res = get_unaligned_le##bits(p + off); \
60 return res; \
61 } \
62 err = map_private_extent_buffer(eb, offset, size, \
63 &kaddr, &map_start, &map_len); \
64 if (err) { \
65 __le##bits leres; \
66 \
67 read_extent_buffer(eb, &leres, offset, size); \
68 return le##bits##_to_cpu(leres); \
69 } \
70 p = kaddr + part_offset - map_start; \
71 res = get_unaligned_le##bits(p + off); \
72 if (token) { \
73 token->kaddr = kaddr; \
74 token->offset = map_start; \
75 token->eb = eb; \
76 } \
77 return res; \
78} \
79void btrfs_set_token_##bits(struct extent_buffer *eb, \
80 const void *ptr, unsigned long off, \
81 u##bits val, \
82 struct btrfs_map_token *token) \
83{ \
84 unsigned long part_offset = (unsigned long)ptr; \
85 unsigned long offset = part_offset + off; \
86 void *p; \
87 int err; \
88 char *kaddr; \
89 unsigned long map_start; \
90 unsigned long map_len; \
91 int size = sizeof(u##bits); \
92 \
93 if (token && token->kaddr && token->offset <= offset && \
94 token->eb == eb && \
95 (token->offset + PAGE_SIZE >= offset + size)) { \
96 kaddr = token->kaddr; \
97 p = kaddr + part_offset - token->offset; \
98 put_unaligned_le##bits(val, p + off); \
99 return; \
100 } \
101 err = map_private_extent_buffer(eb, offset, size, \
102 &kaddr, &map_start, &map_len); \
103 if (err) { \
104 __le##bits val2; \
105 \
106 val2 = cpu_to_le##bits(val); \
107 write_extent_buffer(eb, &val2, offset, size); \
108 return; \
109 } \
110 p = kaddr + part_offset - map_start; \
111 put_unaligned_le##bits(val, p + off); \
112 if (token) { \
113 token->kaddr = kaddr; \
114 token->offset = map_start; \
115 token->eb = eb; \
116 } \
117}
118
119DEFINE_BTRFS_SETGET_BITS(8)
120DEFINE_BTRFS_SETGET_BITS(16)
121DEFINE_BTRFS_SETGET_BITS(32)
122DEFINE_BTRFS_SETGET_BITS(64)
123
124void btrfs_node_key(const struct extent_buffer *eb,
125 struct btrfs_disk_key *disk_key, int nr)
126{
127 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
128 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
129 struct btrfs_key_ptr, key, disk_key);
130}
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}