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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#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}
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}