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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
21/* this is some deeply nasty code. ctree.h has a different
22 * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
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 *
27 * This file declares the macros and then #includes ctree.h, which results
28 * in cpp creating the function here based on the template below.
29 *
30 * These setget functions do all the extent_buffer related mapping
31 * required to efficiently read and write specific fields in the extent
32 * buffers. Every pointer to metadata items in btrfs is really just
33 * an unsigned long offset into the extent buffer which has been
34 * cast to a specific type. This gives us all the gcc type checking.
35 *
36 * The extent buffer api is used to do all the kmapping and page
37 * spanning work required to get extent buffers in highmem and have
38 * a metadata blocksize different from the page size.
39 *
40 * The macro starts with a simple function prototype declaration so that
41 * sparse won't complain about it being static.
42 */
43
44#define BTRFS_SETGET_FUNCS(name, type, member, bits) \
45u##bits btrfs_##name(struct extent_buffer *eb, type *s); \
46void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \
47void btrfs_set_token_##name(struct extent_buffer *eb, type *s, u##bits val, struct btrfs_map_token *token); \
48u##bits btrfs_token_##name(struct extent_buffer *eb, \
49 type *s, struct btrfs_map_token *token) \
50{ \
51 unsigned long part_offset = (unsigned long)s; \
52 unsigned long offset = part_offset + offsetof(type, member); \
53 type *p; \
54 int err; \
55 char *kaddr; \
56 unsigned long map_start; \
57 unsigned long map_len; \
58 unsigned long mem_len = sizeof(((type *)0)->member); \
59 u##bits res; \
60 if (token && token->kaddr && token->offset <= offset && \
61 token->eb == eb && \
62 (token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \
63 kaddr = token->kaddr; \
64 p = (type *)(kaddr + part_offset - token->offset); \
65 res = le##bits##_to_cpu(p->member); \
66 return res; \
67 } \
68 err = map_private_extent_buffer(eb, offset, \
69 mem_len, \
70 &kaddr, &map_start, &map_len); \
71 if (err) { \
72 __le##bits leres; \
73 read_eb_member(eb, s, type, member, &leres); \
74 return le##bits##_to_cpu(leres); \
75 } \
76 p = (type *)(kaddr + part_offset - map_start); \
77 res = le##bits##_to_cpu(p->member); \
78 if (token) { \
79 token->kaddr = kaddr; \
80 token->offset = map_start; \
81 token->eb = eb; \
82 } \
83 return res; \
84} \
85void btrfs_set_token_##name(struct extent_buffer *eb, \
86 type *s, u##bits val, struct btrfs_map_token *token) \
87{ \
88 unsigned long part_offset = (unsigned long)s; \
89 unsigned long offset = part_offset + offsetof(type, member); \
90 type *p; \
91 int err; \
92 char *kaddr; \
93 unsigned long map_start; \
94 unsigned long map_len; \
95 unsigned long mem_len = sizeof(((type *)0)->member); \
96 if (token && token->kaddr && token->offset <= offset && \
97 token->eb == eb && \
98 (token->offset + PAGE_CACHE_SIZE >= offset + mem_len)) { \
99 kaddr = token->kaddr; \
100 p = (type *)(kaddr + part_offset - token->offset); \
101 p->member = cpu_to_le##bits(val); \
102 return; \
103 } \
104 err = map_private_extent_buffer(eb, offset, \
105 mem_len, \
106 &kaddr, &map_start, &map_len); \
107 if (err) { \
108 __le##bits val2; \
109 val2 = cpu_to_le##bits(val); \
110 write_eb_member(eb, s, type, member, &val2); \
111 return; \
112 } \
113 p = (type *)(kaddr + part_offset - map_start); \
114 p->member = cpu_to_le##bits(val); \
115 if (token) { \
116 token->kaddr = kaddr; \
117 token->offset = map_start; \
118 token->eb = eb; \
119 } \
120} \
121void btrfs_set_##name(struct extent_buffer *eb, \
122 type *s, u##bits val) \
123{ \
124 btrfs_set_token_##name(eb, s, val, NULL); \
125} \
126u##bits btrfs_##name(struct extent_buffer *eb, \
127 type *s) \
128{ \
129 return btrfs_token_##name(eb, s, NULL); \
130} \
131
132#include "ctree.h"
133
134void btrfs_node_key(struct extent_buffer *eb,
135 struct btrfs_disk_key *disk_key, int nr)
136{
137 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
138 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
139 struct btrfs_key_ptr, key, disk_key);
140}