2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
19 #include <linux/highmem.h>
21 /* this is some deeply nasty code. ctree.h has a different
22 * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
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
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.
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.
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.
40 * The macro starts with a simple function prototype declaration so that
41 * sparse won't complain about it being static.
44 #define BTRFS_SETGET_FUNCS(name, type, member, bits) \
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); \
47 u##bits btrfs_##name(struct extent_buffer *eb, \
50 unsigned long part_offset = (unsigned long)s; \
51 unsigned long offset = part_offset + offsetof(type, member); \
55 unsigned long map_start; \
56 unsigned long map_len; \
58 err = map_private_extent_buffer(eb, offset, \
59 sizeof(((type *)0)->member), \
60 &kaddr, &map_start, &map_len); \
63 read_eb_member(eb, s, type, member, &leres); \
64 return le##bits##_to_cpu(leres); \
66 p = (type *)(kaddr + part_offset - map_start); \
67 res = le##bits##_to_cpu(p->member); \
70 void btrfs_set_##name(struct extent_buffer *eb, \
71 type *s, u##bits val) \
73 unsigned long part_offset = (unsigned long)s; \
74 unsigned long offset = part_offset + offsetof(type, member); \
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); \
85 val2 = cpu_to_le##bits(val); \
86 write_eb_member(eb, s, type, member, &val2); \
89 p = (type *)(kaddr + part_offset - map_start); \
90 p->member = cpu_to_le##bits(val); \
95 void btrfs_node_key(struct extent_buffer
*eb
,
96 struct btrfs_disk_key
*disk_key
, int nr
)
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
);
This page took 0.034288 seconds and 6 git commands to generate.