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/*
* linux/fs/ext2/dir.c
*
* Copyright (C) 1992, 1993, 1994 Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/dir.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext2 directory handling functions
*/
#include <asm/segment.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/sched.h>
#include <linux/stat.h>
static int ext2_dir_read (struct inode * inode, struct file * filp,
char * buf, int count)
{
return -EISDIR;
}
static int ext2_readdir (struct inode *, struct file *, struct dirent *, int);
static struct file_operations ext2_dir_operations = {
NULL, /* lseek - default */
ext2_dir_read, /* read */
NULL, /* write - bad */
ext2_readdir, /* readdir */
NULL, /* select - default */
ext2_ioctl, /* ioctl */
NULL, /* mmap */
NULL, /* no special open code */
NULL, /* no special release code */
file_fsync /* fsync */
};
/*
* directories can handle most operations...
*/
struct inode_operations ext2_dir_inode_operations = {
&ext2_dir_operations, /* default directory file-ops */
ext2_create, /* create */
ext2_lookup, /* lookup */
ext2_link, /* link */
ext2_unlink, /* unlink */
ext2_symlink, /* symlink */
ext2_mkdir, /* mkdir */
ext2_rmdir, /* rmdir */
ext2_mknod, /* mknod */
ext2_rename, /* rename */
NULL, /* readlink */
NULL, /* follow_link */
NULL, /* bmap */
ext2_truncate, /* truncate */
ext2_permission /* permission */
};
int ext2_check_dir_entry (char * function, struct inode * dir,
struct ext2_dir_entry * de, struct buffer_head * bh,
unsigned long offset)
{
char * error_msg = NULL;
if (de->rec_len < EXT2_DIR_REC_LEN(1))
error_msg = "rec_len is smaller than minimal";
else if (de->rec_len % 4 != 0)
error_msg = "rec_len % 4 != 0";
else if (de->rec_len < EXT2_DIR_REC_LEN(de->name_len))
error_msg = "rec_len is too small for name_len";
else if (dir && ((char *) de - bh->b_data) + de->rec_len >
dir->i_sb->s_blocksize)
error_msg = "directory entry across blocks";
if (error_msg != NULL)
ext2_error (dir->i_sb, function, "bad directory entry: %s\n"
"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
error_msg, offset, de->inode, de->rec_len,
de->name_len);
return error_msg == NULL ? 1 : 0;
}
static int ext2_readdir (struct inode * inode, struct file * filp,
struct dirent * dirent, int count)
{
unsigned long offset, blk;
int i, num;
struct buffer_head * bh, * tmp, * bha[16];
struct ext2_dir_entry * de;
struct super_block * sb;
int err;
if (!inode || !S_ISDIR(inode->i_mode))
return -EBADF;
sb = inode->i_sb;
while (filp->f_pos < inode->i_size) {
offset = filp->f_pos & (sb->s_blocksize - 1);
blk = (filp->f_pos) >> EXT2_BLOCK_SIZE_BITS(sb);
bh = ext2_bread (inode, blk, 0, &err);
if (!bh) {
filp->f_pos += sb->s_blocksize - offset;
continue;
}
/*
* Do the readahead
*/
if (!offset) {
for (i = 16 >> (EXT2_BLOCK_SIZE_BITS(sb) - 9), num = 0;
i > 0; i--) {
tmp = ext2_getblk (inode, ++blk, 0, &err);
if (tmp && !tmp->b_uptodate && !tmp->b_lock)
bha[num++] = tmp;
else
brelse (tmp);
}
if (num) {
ll_rw_block (READA, num, bha);
for (i = 0; i < num; i++)
brelse (bha[i]);
}
}
de = (struct ext2_dir_entry *) (offset + bh->b_data);
while (offset < sb->s_blocksize && filp->f_pos < inode->i_size) {
if (!ext2_check_dir_entry ("ext2_readdir", inode, de,
bh, offset)) {
brelse (bh);
return 0;
}
offset += de->rec_len;
filp->f_pos += de->rec_len;
if (de->inode) {
memcpy_tofs (dirent->d_name, de->name,
de->name_len);
put_fs_long (de->inode, &dirent->d_ino);
put_fs_byte (0, de->name_len + dirent->d_name);
put_fs_word (de->name_len, &dirent->d_reclen);
#ifndef DONT_USE_DCACHE
ext2_dcache_add (inode->i_dev, inode->i_ino,
de->name, de->name_len,
de->inode);
#endif
i = de->name_len;
brelse (bh);
if (!IS_RDONLY(inode)) {
inode->i_atime = CURRENT_TIME;
inode->i_dirt = 1;
}
return i;
}
de = (struct ext2_dir_entry *) ((char *) de +
de->rec_len);
}
brelse (bh);
}
if (!IS_RDONLY(inode)) {
inode->i_atime = CURRENT_TIME;
inode->i_dirt = 1;
}
return 0;
}