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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); \
47u##bits btrfs_##name(struct extent_buffer *eb, \
48 type *s) \
49{ \
50 unsigned long part_offset = (unsigned long)s; \
51 unsigned long offset = part_offset + offsetof(type, member); \
52 type *p; \
53 int err; \
54 char *kaddr; \
55 unsigned long map_start; \
56 unsigned long map_len; \
57 u##bits res; \
58 err = map_private_extent_buffer(eb, offset, \
59 sizeof(((type *)0)->member), \
60 &kaddr, &map_start, &map_len); \
61 if (err) { \
62 __le##bits leres; \
63 read_eb_member(eb, s, type, member, &leres); \
64 return le##bits##_to_cpu(leres); \
65 } \
66 p = (type *)(kaddr + part_offset - map_start); \
67 res = le##bits##_to_cpu(p->member); \
68 return res; \
69} \
70void btrfs_set_##name(struct extent_buffer *eb, \
71 type *s, u##bits val) \
72{ \
73 unsigned long part_offset = (unsigned long)s; \
74 unsigned long offset = part_offset + offsetof(type, member); \
75 type *p; \
76 int err; \
77 char *kaddr; \
78 unsigned long map_start; \
79 unsigned long map_len; \
80 err = map_private_extent_buffer(eb, offset, \
81 sizeof(((type *)0)->member), \
82 &kaddr, &map_start, &map_len); \
83 if (err) { \
84 __le##bits val2; \
85 val2 = cpu_to_le##bits(val); \
86 write_eb_member(eb, s, type, member, &val2); \
87 return; \
88 } \
89 p = (type *)(kaddr + part_offset - map_start); \
90 p->member = cpu_to_le##bits(val); \
91}
92
93#include "ctree.h"
94
95void btrfs_node_key(struct extent_buffer *eb,
96 struct btrfs_disk_key *disk_key, int nr)
97{
98 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
99 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
100 struct btrfs_key_ptr, key, disk_key);
101}
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 wrappers 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_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_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}