Kernel system call안에서 파일 퍼미션 알아내는 방법?

	//check if the file exists and has write permission
	if (sys_access(filename, W_OK) < 0) { 
		printk("File with write permission not found.\n"); //debug
		return -ENOENT;
	}
 
	//try creating the attribute directory
	//  first get the file permission
	filestat = (struct stat*) kmalloc(sizeof(struct stat), GFP_KERNEL);
	if(sys_stat(filename, filestat) < 0) { //SYSTEM CALL!
		printk("Stat failed.\n"); //debug
		return -ENOENT;
	}