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0f82731f CM |
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> | |
d352ac68 CM |
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. | |
c99e905c CM |
39 | * |
40 | * The macro starts with a simple function prototype declaration so that | |
41 | * sparse won't complain about it being static. | |
d352ac68 CM |
42 | */ |
43 | ||
0f82731f | 44 | #define BTRFS_SETGET_FUNCS(name, type, member, bits) \ |
c99e905c CM |
45 | u##bits btrfs_##name(struct extent_buffer *eb, type *s); \ |
46 | void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \ | |
cfed81a0 CM |
47 | void btrfs_set_token_##name(struct extent_buffer *eb, type *s, u##bits val, struct btrfs_map_token *token); \ |
48 | u##bits btrfs_token_##name(struct extent_buffer *eb, \ | |
49 | type *s, struct btrfs_map_token *token) \ | |
0f82731f | 50 | { \ |
df68b8a7 DM |
51 | unsigned long part_offset = (unsigned long)s; \ |
52 | unsigned long offset = part_offset + offsetof(type, member); \ | |
53 | type *p; \ | |
a6591715 CM |
54 | int err; \ |
55 | char *kaddr; \ | |
56 | unsigned long map_start; \ | |
57 | unsigned long map_len; \ | |
cfed81a0 | 58 | unsigned long mem_len = sizeof(((type *)0)->member); \ |
a6591715 | 59 | u##bits res; \ |
cfed81a0 CM |
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 | } \ | |
a6591715 | 68 | err = map_private_extent_buffer(eb, offset, \ |
cfed81a0 | 69 | mem_len, \ |
a6591715 CM |
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); \ | |
cfed81a0 CM |
78 | if (token) { \ |
79 | token->kaddr = kaddr; \ | |
80 | token->offset = map_start; \ | |
81 | token->eb = eb; \ | |
82 | } \ | |
a6591715 | 83 | return res; \ |
0f82731f | 84 | } \ |
cfed81a0 CM |
85 | void btrfs_set_token_##name(struct extent_buffer *eb, \ |
86 | type *s, u##bits val, struct btrfs_map_token *token) \ | |
0f82731f | 87 | { \ |
df68b8a7 DM |
88 | unsigned long part_offset = (unsigned long)s; \ |
89 | unsigned long offset = part_offset + offsetof(type, member); \ | |
90 | type *p; \ | |
a6591715 CM |
91 | int err; \ |
92 | char *kaddr; \ | |
93 | unsigned long map_start; \ | |
94 | unsigned long map_len; \ | |
cfed81a0 CM |
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 | } \ | |
a6591715 | 104 | err = map_private_extent_buffer(eb, offset, \ |
cfed81a0 | 105 | mem_len, \ |
a6591715 CM |
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); \ | |
cfed81a0 CM |
115 | if (token) { \ |
116 | token->kaddr = kaddr; \ | |
117 | token->offset = map_start; \ | |
118 | token->eb = eb; \ | |
119 | } \ | |
120 | } \ | |
121 | void btrfs_set_##name(struct extent_buffer *eb, \ | |
122 | type *s, u##bits val) \ | |
123 | { \ | |
124 | btrfs_set_token_##name(eb, s, val, NULL); \ | |
125 | } \ | |
126 | u##bits btrfs_##name(struct extent_buffer *eb, \ | |
127 | type *s) \ | |
128 | { \ | |
129 | return btrfs_token_##name(eb, s, NULL); \ | |
130 | } \ | |
0f82731f CM |
131 | |
132 | #include "ctree.h" | |
133 | ||
e644d021 CM |
134 | void 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); | |
e644d021 CM |
138 | read_eb_member(eb, (struct btrfs_key_ptr *)ptr, |
139 | struct btrfs_key_ptr, key, disk_key); | |
140 | } |