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/* namei.c
name lookup for EFS filesystem
(C)95,96 Christian Vogelgsang
*/
#include <linux/sched.h>
#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/efs_fs_sb.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
/* ----- efs_find_entry -----
search a raw efs dir entry for the given name
dir - inode of directory
oname - name to search for
onamelen- length of name
return - inode number of the found entry or 0 on error
*/
static struct buffer_head * efs_find_entry(struct inode *dir,
const char *oname,
int onamelen,
struct efs_dir_entry *res_dir)
{
struct efs_inode_info *ini = &dir->u.efs_i;
struct buffer_head *bh = NULL;
__u32 inode;
__u16 i;
__u8 *name;
__u16 namelen;
__u32 blknum,b;
struct efs_dirblk *db;
/* Warnings */
if(ini->tot!=1)
printk("efs_find: More than one extent!\n");
if(dir->i_size & (EFS_BLOCK_SIZE-1))
printk("efs_find: dirsize != blocklen * n\n");
/* Search in every dirblock */
inode = 0;
blknum = dir->i_size >> EFS_BLOCK_SIZE_BITS;
#ifdef DEBUG_EFS
printk("EFS: directory with inode %#xd has %d blocks\n",
dir->i_ino, blknum);
#endif
for(b=0;b<blknum;b++) {
int db_offset;
#ifdef DEBUG_EFS
printk("EFS: trying block %d\n", b);
#endif
/* Read a raw dirblock */
bh = bread(dir->i_dev,efs_bmap(dir,b),EFS_BLOCK_SIZE);
if(!bh) {
printk("EFS: efs_bmap returned NULL!\n");
return 0;
}
db = (struct efs_dirblk *)bh->b_data;
if (db->db_magic != EFS_DIRBLK_MAGIC) {
printk("EFS: dirblk has bad magic (%#xl)!\n",
db->db_magic);
return NULL;
}
#ifdef DEBUG_EFS
printk("EFS: db %d has %d entries, starting at offset %#x\n",
b, db->db_slots, (__u16)db->db_firstused << 1);
#endif
for(i = 0 ; i < db->db_slots ; i++) {
struct efs_dent * de;
int entry_inode;
db_offset = ((__u16)db->db_space[i] << 1)
- EFS_DIRBLK_HEADERSIZE;
de = (struct efs_dent *)(&db->db_space[db_offset]);
/* inode, namelen and name of direntry */
entry_inode = efs_swab32(de->ud_inum.l);
namelen = de->d_namelen;
name = de->d_name;
#ifdef 0
printk("EFS: entry %d @ %#x has inode %#x, %s/%d\n",
i, db_offset, entry_inode, name, namelen);
#endif
/* we found the name! */
if((namelen==onamelen)&&
(!memcmp(oname,name,onamelen))) {
res_dir->inode = entry_inode;
#ifdef DEBUG_EFS
printk("EFS: found inode %d\n",
entry_inode);
#endif
return bh;
}
}
}
#ifdef DEBUG_EFS
printk("EFS: efs_find_entry didn't find inode for \"%s\"/%d!\n",
oname, onamelen);
#endif
return NULL;
/* not reached */
}
/* ----- efs_lookup -----
lookup inode operation:
check if a given name is in the dir directory
dir - pointer to inode of directory
name - name we must search for
len - length of name
result - pointer to inode struct if we found it or NULL on error
return - 0 everything is ok or <0 on error
*/
int efs_lookup(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = NULL;
struct buffer_head *bh;
struct efs_dir_entry de;
bh = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
if (bh) {
int ino = de.inode;
brelse(bh);
inode = iget(dir->i_sb, ino);
if (!inode)
return -EACCES;
}
d_add(dentry, inode);
return 0;
}
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