Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ia0-f174.google.com ([209.85.210.174]:41906 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753523Ab2KIBgW convert rfc822-to-8bit (ORCPT ); Thu, 8 Nov 2012 20:36:22 -0500 Received: by mail-ia0-f174.google.com with SMTP id y32so2408136iag.19 for ; Thu, 08 Nov 2012 17:36:22 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20121108122742.GB22735@fieldses.org> References: <1351760297.5369.1.camel@localhost> <20121107190111.GC7421@fieldses.org> <20121108122742.GB22735@fieldses.org> Date: Fri, 9 Nov 2012 09:36:22 +0800 Message-ID: Subject: Re: hang problem when umount a nfs point From: Jack Wang To: "J. Bruce Fields" Cc: =?UTF-8?Q?Mart=C3=ADn_Cigorraga?= , dahai_tian@usish.com, linux-nfs@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: 2012/11/8 J. Bruce Fields : > On Thu, Nov 08, 2012 at 11:03:22AM +0800, Jack Wang wrote: >> 2012/11/8 J. Bruce Fields : >> > On Wed, Nov 07, 2012 at 09:05:51AM +0800, Jack Wang wrote: >> >> 2012/11/7 Martín Cigorraga : >> >> > On Mon, Nov 5, 2012 at 10:27 PM, Jack Wang >> >> > wrote: >> >> >> >> >> >> Hi all, >> >> >> >> >> >> Anyone who can kindly give some suggestion? or we just put question to >> >> >> the wrong list? >> >> >> >> >> >> Thanks. >> >> >> >> >> >> Jack >> >> >> >> >> >> 2012/11/1 dahai_tian : >> >> >> > Hi all: >> >> >> > I mount a local directory to a nfs server. When nfs server is >> >> >> > stopped >> >> >> > for some accidental cause, I try to umount the mount point, the umount >> >> >> > command will hang and 'time out' messages are continually printed in the >> >> >> > terminal. How can I avoid hanging in this case? BTW, This issue does not >> >> >> > exist when I changed nfs version from 4 to 3. >> >> >> > Look forward to your response, thanks! >> >> >> >> > >> >> > Hi Jack, use the -l (lazy) switch: >> >> > # umount -l {your mounted nfs share} >> >> > >> >> > Also, I wouldn't recommend 'just to kill' the NFS proces(ses) as it (them) >> >> > may leave shared memory a mess. >> >> > (And I would like to see how do you make to mount any NFS share again >> >> > without booting) >> >> >> >> Thanks Martin for kindly help. >> >> >> >> umount -l did work, but why nfsv3 do not have this problem? >> > >> > I don't know what it is exactly. But in general I wouldn't expect >> > umount to work when the server's unavailable. >> > >> > --b. >> >> Thanks for your time Bruce, but there are chance the server >> unavailable , why you think umount don't work is expected? > > It's tough for the client to deal safely with an unreachable server. > Worst case it may still have data in its buffers that applications have > written but that hasn't yet made it to the server. > > If you don't have any opens or other state on the filesystem any more, > there might be things that could be done to make it easier to umount in > that case--I haven't thought it through--but I doubt that's a high > priority, so it's likely up to you to write the code and persuade people > it's worthwhile. > > --b. Thanks for explaination. Jack