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/* 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;
struct efs_dirblk *dirblk;
__u32 iteminode;
__u16 namelen;
char *nameptr;
__u16 itemnum;
__u32 block;
int db_offset;
int error = 0;
struct efs_dent *de = NULL;
/* some checks -- ISDIR should be done by upper layer */
if(!inode || !inode->i_sb || !S_ISDIR(inode->i_mode)) {
printk("EFS: bad inode for readdir!\n");
return -EBADF;
}
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 -EBADF;
}
/* Warnings */
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)) {
printk("EFS: read all entries -- done\n");
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) {
/* XXX try next block? */
return -EBADF;
}
/* from here on, we must exit through out: to release bh */
/* dirblock */
dirblk = (struct efs_dirblk *)bh->b_data;
if (dirblk->db_magic != EFS_DIRBLK_MAGIC) {
printk("EFS: bad dirblk magic %#xl\n", dirblk->db_magic);
error = -EBADF;
goto out;
}
db_offset = ((__u16)dirblk->db_space[itemnum] << 1)
- EFS_DIRBLK_HEADERSIZE;
de = (struct efs_dent *)(&dirblk->db_space[db_offset]);
if (dirblk->db_slots == 0) {
error = 0;
goto out;
}
#ifdef DEBUG_EFS_DIRS
if (itemnum == 0) {
printk("efs: readdir: db %d has %d entries, starting at offset %0#x\n",
block, dirblk->db_slots, (__u16)dirblk->db_firstused << 1);
}
#endif
/* diritem first contains the inode number, the namelen and the name */
iteminode = EFS_DE_GET_INUM(de);
namelen = de->d_namelen;
nameptr = de->d_name;
#ifdef DEBUG_EFS_DIRS
printk("efs: dir #%d @ %0#x - inode %#0x %*s namelen %u\n",
itemnum,db_offset,iteminode, namelen,
nameptr ? nameptr : "(null)", namelen);
#endif
/* copy filename and data in direntry */
error = filldir(dirent,nameptr,namelen,filp->f_pos,iteminode);
if (error)
goto out;
/* store pos of next item */
itemnum++;
if(itemnum == dirblk->db_slots) {
itemnum = 0;
block++;
}
filp->f_pos = (block<<EFS_BLOCK_SIZE_BITS) | itemnum;
UPDATE_ATIME(inode);
out:
brelse(bh);
return error;
}
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