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
137
|
/* dir.c
directory inode operations for EFS filesystem
(C)95,96 Christian Vogelgsang
*/
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/efs_fs.h>
#include <linux/efs_fs_i.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
static int efs_readdir(struct file *,void *,filldir_t);
extern int efs_lookup(struct inode *, struct dentry *);
static struct file_operations efs_dir_ops = {
NULL,
NULL,
NULL,
efs_readdir,
NULL,
NULL,
NULL,
NULL,
NULL
};
struct inode_operations efs_dir_in_ops = {
&efs_dir_ops,
NULL,
efs_lookup,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
efs_bmap,
NULL,
NULL
};
/* ----- efs_readdir -----
readdir inode operation:
read the next directory entry of a given dir file
inode - pointer to inode struct of directory
filp - pointer to file struct of directory inode
dirent - pointer to dirent struct that has to be filled
filldir - function to store values in the directory
return - 0 ok, <0 error
*/
static int efs_readdir(struct file *filp,
void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_dentry->d_inode;
struct efs_inode_info *ini = (struct efs_inode_info *)&inode->u.efs_i;
struct buffer_head *bh;
__u8 *rawdirblk;
__u32 iteminode;
__u16 namelen;
__u8 *nameptr;
__u32 numitems;
__u16 itemnum;
__u32 block;
__u16 rawdepos;
/* some checks */
if(!inode || !inode->i_sb || !S_ISDIR(inode->i_mode))
return -EBADF;
/* Warnings */
if(ini->tot!=1) {
printk("EFS: directory %s has more than one extent.\n",
filp->f_dentry->d_name.name);
printk("EFS: Mike is lazy, so we can't handle this yet. Sorry =(\n");
return 0;
}
if(inode->i_size & (EFS_BLOCK_SIZE-1))
printk("efs_readdir: dirsize != blocksize*n\n");
/* f_pos contains: dirblock<<BLOCK_SIZE | # of item in dirblock */
block = filp->f_pos >> EFS_BLOCK_SIZE_BITS;
itemnum = filp->f_pos & 0xff;
/* We found the last entry -> ready */
if(block == (inode->i_size>>EFS_BLOCK_SIZE_BITS))
return 0;
/* get disc block number from dir block num: 0..i_size/BLOCK_SIZE */
bh = bread(inode->i_dev,efs_bmap(inode,block),EFS_BLOCK_SIZE);
if(!bh) return 0;
/* dirblock */
rawdirblk = (__u8 *)bh->b_data;
/* number of entries stored in this dirblock */
numitems = rawdirblk[EFS_DB_ENTRIES];
/* offset in block of #off diritem */
rawdepos = (__u16)rawdirblk[EFS_DB_FIRST+itemnum]<<1;
/* diritem first contains the inode number, the namelen and the name */
iteminode = ConvertLong(rawdirblk,rawdepos);
namelen = (__u16)rawdirblk[rawdepos+EFS_DI_NAMELEN];
nameptr = rawdirblk + rawdepos + EFS_DI_NAME;
#ifdef DEBUG_EFS
printk("efs: dir #%d @ %0#3x - inode %lx %s namelen %u\n",
itemnum,rawdepos,iteminode,nameptr,namelen);
#endif
/* copy filename and data in direntry */
filldir(dirent,nameptr,namelen,filp->f_pos,iteminode);
brelse(bh);
/* store pos of next item */
itemnum++;
if(itemnum==numitems) {
itemnum = 0;
block++;
}
filp->f_pos = (block<<EFS_BLOCK_SIZE_BITS) | itemnum;
UPDATE_ATIME(inode);
return 0;
}
|
