jfs_iget
extern struct inode *jfs_iget(struct super_block *, unsigned long);
ip = jfs_iget(dip->i_sb, inum);
inode = jfs_iget(sb, ino);
return d_obtain_alias(jfs_iget(dentry->d_sb, parent_ino));
inode = jfs_iget(sb, ROOT_I);