新手问题.关于express文件上传error:ENOENT,No such file or directory的问题

exports.submit = function(req, res, next){
var original_path = req.files.filesubmit.path;
var target_path = './submitted/';

console.log(path.existsSync(original_path));//-----------//TRUE!

fs.rename(original_path, target_path, function(err){
	if (err) throw err;//------//error:ENOENT,No such file or directory
	fs.unlink(tmp_path, function(){
	//	ir (err) throw err;
		res.send('submitted');
	})
})
}

明明path.existsSync(original_path)是TRUE，
为何抛出error:ENOENT,No such file or directory