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
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
/*
* linux/fs/fat/file.c
*
* Written 1992,1993 by Werner Almesberger
*
* regular file handling primitives for fat-based filesystems
*/
#include <linux/sched.h>
#include <linux/locks.h>
#include <linux/fs.h>
#include <linux/msdos_fs.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include <linux/fat_cvf.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#define PRINTK(x)
#define Printk(x) printk x
struct file_operations fat_file_operations = {
llseek: generic_file_llseek,
read: fat_file_read,
write: fat_file_write,
mmap: generic_file_mmap,
fsync: file_fsync,
};
struct inode_operations fat_file_inode_operations = {
truncate: fat_truncate,
setattr: fat_notify_change,
};
ssize_t fat_file_read(
struct file *filp,
char *buf,
size_t count,
loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
return MSDOS_SB(inode->i_sb)->cvf_format
->cvf_file_read(filp,buf,count,ppos);
}
int fat_get_block(struct inode *inode, long iblock, struct buffer_head *bh_result, int create)
{
struct super_block *sb = inode->i_sb;
unsigned long phys;
phys = fat_bmap(inode, iblock);
if (phys) {
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
return 0;
}
if (!create)
return 0;
if (iblock << sb->s_blocksize_bits != MSDOS_I(inode)->mmu_private) {
BUG();
return -EIO;
}
if (!(iblock % MSDOS_SB(inode->i_sb)->cluster_size)) {
if (fat_add_cluster(inode) < 0)
return -ENOSPC;
}
MSDOS_I(inode)->mmu_private += sb->s_blocksize;
phys = fat_bmap(inode, iblock);
if (!phys)
BUG();
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
bh_result->b_state |= (1UL << BH_New);
return 0;
}
ssize_t fat_file_write(
struct file *filp,
const char *buf,
size_t count,
loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
struct super_block *sb = inode->i_sb;
return MSDOS_SB(sb)->cvf_format
->cvf_file_write(filp,buf,count,ppos);
}
ssize_t default_fat_file_write(
struct file *filp,
const char *buf,
size_t count,
loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
int retval;
retval = generic_file_write(filp, buf, count, ppos);
if (retval > 0) {
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
mark_inode_dirty(inode);
}
return retval;
}
void fat_truncate(struct inode *inode)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
int cluster;
/* Why no return value? Surely the disk could fail... */
if (IS_RDONLY (inode))
return /* -EPERM */;
if (IS_IMMUTABLE(inode))
return /* -EPERM */;
cluster = 1 << sbi->cluster_bits;
/*
* This protects against truncating a file bigger than it was then
* trying to write into the hole.
*/
if (MSDOS_I(inode)->mmu_private > inode->i_size)
MSDOS_I(inode)->mmu_private = inode->i_size;
fat_free(inode, (inode->i_size + (cluster - 1)) >> sbi->cluster_bits);
MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
mark_inode_dirty(inode);
}
|
