From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fieldses.org ([174.143.236.118]:57863 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757362Ab0IGRcK (ORCPT ); Tue, 7 Sep 2010 13:32:10 -0400 Date: Tue, 7 Sep 2010 13:31:18 -0400 To: Jeff Layton Cc: "Tayade, Nilesh" , Bian Naimeng , linux-nfs@vger.kernel.org Subject: Re: Query regarding NFS packet capture at application layer - umount operation. Message-ID: <20100907173118.GC13022@fieldses.org> References: <4C85EE24.9070007@cn.fujitsu.com> <20100907131902.3f22b411@tlielax.poochiereds.net> Content-Type: text/plain; charset=us-ascii In-Reply-To: <20100907131902.3f22b411@tlielax.poochiereds.net> From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Tue, Sep 07, 2010 at 01:19:02PM -0400, Jeff Layton wrote: > On Tue, 7 Sep 2010 04:02:29 -0400 > "Tayade, Nilesh" wrote: > > > > -----Original Message----- > > > From: Bian Naimeng [mailto:biannm@cn.fujitsu.com] > > > Sent: Tuesday, September 07, 2010 1:18 PM > > > To: Tayade, Nilesh > > > Cc: linux-nfs@vger.kernel.org > > > Subject: Re: Query regarding NFS packet capture at application layer > > > - umount operation. > > > > > > > > > > > Could someone please explain why there is no NFS packet observed > > > during > > > > an unmount? Also there seems not much information, related to NFS > > > mount > > > > point being unmounted, in TCP packet. So is there any way to > > > detect the > > > > unmount operation by hacking such packets? > > > > > > > > > > I guess you used NFSv4. NFSv4 umount operation does not send any > > > NFS packet. > > > The TCP packets you captured were sent by TCP close procedure, > > > because NFS > > > umount operation need close the TCP connection with NFS server. > > > > I am using NFSv3. (Sorry, I forgot to mention it in first email - so I > > have replied to my original email with capture file). > > > > I'm fairly sure that's still handled by the userspace piece. Do you > have a /sbin/umount.nfs? If not, that may be why. Or if you're only capturing traffic to port 2049, that would also explain why you don't see anything. (NFSv2/v3 mount/umount use different protocol.) --b.