$path = date('Y').'/'.date('m').'/'.date('d');
$result=Storage::disk('upyun')->writeStream($path,fopen($request->file('file'),'r'));

一直返回 File already exists at path: 2019/03/15

$entension = $file ->getClientOriginalExtension();

        $new_name = date('YmdHis') . mt_rand(1001, 9999) . '.' . $entension;
        $path = date('Y').'/'.date('m').'/'.date('d').$new_name;
        $result=Storage::disk('upyun')->writeStream($path,fopen($request->file('file'),'r'));

如果这样写，直接服务器就500了