1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/*
* linux/fs/ext2/xip.c
*
* Copyright (C) 2005 IBM Corporation
* Author: Carsten Otte (cotte@de.ibm.com)
*/
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/buffer_head.h>
#include <linux/ext2_fs_sb.h>
#include <linux/ext2_fs.h>
#include "ext2.h"
#include "xip.h"
static inline int
__inode_direct_access(struct inode *inode, sector_t sector,
void **kaddr, unsigned long *pfn)
{
struct block_device *bdev = inode->i_sb->s_bdev;
struct block_device_operations *ops = bdev->bd_disk->fops;
BUG_ON(!ops->direct_access);
return ops->direct_access(bdev, sector, kaddr, pfn);
}
static inline int
__ext2_get_sector(struct inode *inode, sector_t offset, int create,
sector_t *result)
{
struct buffer_head tmp;
int rc;
memset(&tmp, 0, sizeof(struct buffer_head));
rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
create);
*result = tmp.b_blocknr;
/* did we get a sparse block (hole in the file)? */
if (!tmp.b_blocknr && !rc) {
BUG_ON(create);
rc = -ENODATA;
}
return rc;
}
int
ext2_clear_xip_target(struct inode *inode, int block)
{
sector_t sector = block * (PAGE_SIZE/512);
void *kaddr;
unsigned long pfn;
int rc;
rc = __inode_direct_access(inode, sector, &kaddr, &pfn);
if (!rc)
clear_page(kaddr);
return rc;
}
void ext2_xip_verify_sb(struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
!sb->s_bdev->bd_disk->fops->direct_access) {
sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
ext2_warning(sb, __FUNCTION__,
"ignoring xip option - not supported by bdev");
}
}
struct page *
ext2_get_xip_page(struct address_space *mapping, sector_t offset,
int create)
{
int rc;
void *kaddr;
unsigned long pfn;
sector_t sector;
/* first, retrieve the sector number */
rc = __ext2_get_sector(mapping->host, offset, create, §or);
if (rc)
goto error;
/* retrieve address of the target data */
rc = __inode_direct_access
(mapping->host, sector * (PAGE_SIZE/512), &kaddr, &pfn);
if (!rc)
return pfn_to_page(pfn);
error:
return ERR_PTR(rc);
}
|
