hfs: SMP race on directory close()

->open_dir_list needs protection...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/hfs/dir.c

@@ -176,7 +176,9 @@ static int hfs_dir_release(struct inode *inode, struct file *file)
 {
 	struct hfs_readdir_data *rd = file->private_data;
 	if (rd) {
+		mutex_lock(&inode->i_mutex);
 		list_del(&rd->list);
+		mutex_unlock(&inode->i_mutex);
 		kfree(rd);
 	}
 	return 0;