Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ig0-f169.google.com ([209.85.213.169]:58756 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752709AbaHBDod (ORCPT ); Fri, 1 Aug 2014 23:44:33 -0400 MIME-Version: 1.0 In-Reply-To: <20140802131946.207c597c@notabene.brown> References: <53DA8443.407@candelatech.com> <20140801064217.01852788@notabene.brown> <53DAB307.2000206@candelatech.com> <20140801075053.2120cb33@notabene.brown> <20140801212120.1ae0eb02@tlielax.poochiereds.net> <20140802131946.207c597c@notabene.brown> Date: Fri, 1 Aug 2014 23:44:32 -0400 Message-ID: Subject: Re: Killing process in D state on mount to dead NFS server. (when process is in fsync) From: Trond Myklebust To: NeilBrown Cc: Jeff Layton , Ben Greear , Andrew Morton , "linux-nfs@vger.kernel.org" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Aug 1, 2014 at 11:19 PM, NeilBrown wrote: > On Fri, 1 Aug 2014 22:55:42 -0400 Trond Myklebust wrote: > >> > That still leaves some open questions though... >> > >> > Is that enough to fix it? You'd still have the dirty pages lingering >> > around, right? Would a umount -f presumably work at that point? >> >> 'umount -f' will kill any outstanding RPC calls that are causing the >> mount to hang, but doesn't do anything to change page states or NFS >> file/lock states. > > Should it though? > > MNT_FORCE (since Linux 2.1.116) > Force unmount even if busy. This can cause data loss. (Only > for NFS mounts.) > > Given that data loss is explicitly permitted, I suspect it should. > > Can we make MNT_FORCE on NFS not only abort outstanding RPC calls, but > fail all subsequent RPC calls? That might make it really useful. You > wouldn't even need to "kill -9" then. Yes, but if the umount fails due to other conditions (for example an application happens to still have a file open on that volume) then that could leave you with a persistent messy situation on your hands. Cheers Trond