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c1d7c514 | 1 | // SPDX-License-Identifier: GPL-2.0 |
0f82731f CM |
2 | /* |
3 | * Copyright (C) 2007 Oracle. All rights reserved. | |
0f82731f CM |
4 | */ |
5 | ||
18077bb4 | 6 | #include <asm/unaligned.h> |
d352ac68 | 7 | |
18077bb4 LZ |
8 | #include "ctree.h" |
9 | ||
10 | static inline u8 get_unaligned_le8(const void *p) | |
11 | { | |
12 | return *(u8 *)p; | |
13 | } | |
14 | ||
15 | static inline void put_unaligned_le8(u8 val, void *p) | |
16 | { | |
17 | *(u8 *)p = val; | |
18 | } | |
19 | ||
20 | /* | |
21 | * this is some deeply nasty code. | |
d352ac68 CM |
22 | * |
23 | * The end result is that anyone who #includes ctree.h gets a | |
18077bb4 | 24 | * declaration for the btrfs_set_foo functions and btrfs_foo functions, |
01327610 | 25 | * which are wrappers of btrfs_set_token_#bits functions and |
18077bb4 | 26 | * btrfs_get_token_#bits functions, which are defined in this file. |
d352ac68 CM |
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 | * | |
18077bb4 LZ |
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. | |
cb495113 DS |
36 | * |
37 | * There are 2 variants defined, one with a token pointer and one without. | |
d352ac68 CM |
38 | */ |
39 | ||
18077bb4 | 40 | #define DEFINE_BTRFS_SETGET_BITS(bits) \ |
1cbb1f45 JM |
41 | u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \ |
42 | const void *ptr, unsigned long off, \ | |
18077bb4 | 43 | struct btrfs_map_token *token) \ |
0f82731f | 44 | { \ |
18077bb4 LZ |
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 | \ | |
48bc3950 | 55 | ASSERT(token); \ |
c82f823c | 56 | ASSERT(token->eb == eb); \ |
48bc3950 DS |
57 | \ |
58 | if (token->kaddr && token->offset <= offset && \ | |
ea1754a0 | 59 | (token->offset + PAGE_SIZE >= offset + size)) { \ |
18077bb4 LZ |
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); \ | |
48bc3950 DS |
75 | token->kaddr = kaddr; \ |
76 | token->offset = map_start; \ | |
18077bb4 | 77 | return res; \ |
0f82731f | 78 | } \ |
cb495113 DS |
79 | u##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 | } \ | |
18077bb4 | 104 | void btrfs_set_token_##bits(struct extent_buffer *eb, \ |
1cbb1f45 JM |
105 | const void *ptr, unsigned long off, \ |
106 | u##bits val, \ | |
18077bb4 | 107 | struct btrfs_map_token *token) \ |
0f82731f | 108 | { \ |
18077bb4 LZ |
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 | \ | |
48bc3950 | 118 | ASSERT(token); \ |
c82f823c | 119 | ASSERT(token->eb == eb); \ |
48bc3950 DS |
120 | \ |
121 | if (token->kaddr && token->offset <= offset && \ | |
ea1754a0 | 122 | (token->offset + PAGE_SIZE >= offset + size)) { \ |
18077bb4 LZ |
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); \ | |
48bc3950 DS |
139 | token->kaddr = kaddr; \ |
140 | token->offset = map_start; \ | |
cb495113 DS |
141 | } \ |
142 | void 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); \ | |
18077bb4 | 165 | } |
0f82731f | 166 | |
18077bb4 LZ |
167 | DEFINE_BTRFS_SETGET_BITS(8) |
168 | DEFINE_BTRFS_SETGET_BITS(16) | |
169 | DEFINE_BTRFS_SETGET_BITS(32) | |
170 | DEFINE_BTRFS_SETGET_BITS(64) | |
0f82731f | 171 | |
1cbb1f45 | 172 | void btrfs_node_key(const struct extent_buffer *eb, |
e644d021 CM |
173 | struct btrfs_disk_key *disk_key, int nr) |
174 | { | |
175 | unsigned long ptr = btrfs_node_key_ptr_offset(nr); | |
e644d021 CM |
176 | read_eb_member(eb, (struct btrfs_key_ptr *)ptr, |
177 | struct btrfs_key_ptr, key, disk_key); | |
178 | } |