Re: [PATCH] cifs/smb3: directory sync should not return an error

From: Jeremy Allison <jra@samba.org>
To: Steve French <smfrench@gmail.com>
Cc: ronnie sahlberg <ronniesahlberg@gmail.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	CIFS <linux-cifs@vger.kernel.org>,
	Pavel Shilovsky <pavel.shilovsky@gmail.com>,
	samba-technical <samba-technical@lists.samba.org>
Subject: Re: [PATCH] cifs/smb3: directory sync should not return an error
Date: Thu, 10 May 2018 16:06:52 -0700	[thread overview]
Message-ID: <20180510230652.GB203322@jra3> (raw)
In-Reply-To: <CAH2r5msDLZhbj_MUiFp-zcT7hZ0t7gv3OrTgr61JYcKCj9Kfzw@mail.gmail.com>

On Thu, May 10, 2018 at 05:25:55PM -0500, Steve French wrote:
> 
> Current behavior seems to be that (for SMB2/SMB3 as with NFS)
> servers are not expected to cache file creates.   If we send a flush over
> the wire without a lot more testing we could break even more apps - unless
> we simply send the request and ignore the return code which I would prefer
> not to do until we get feedback from more servers and clarification from
> MS-SMB2).  What we don't want to do is pass EINVAL back which breaks some.
> 
> Ronnie said it well:
> " If/once ms-smb2.pdf is updated to describe the semantics for flush
> on a directory, then we can think about using flush here. Not before.
> Otherwise we just revert back to chasing implementation specific
> behavior" (as we did with SMB1)
> 
> (so fix the current behavior - then think about whether we can safely
> send this as a flush if there are any valid cases which MS-SMB2
> exposes in the future).

In the meantime I'm going to fix the smbd server to act
the same way that Windows Does (TM). That's what real
clients expect :-).