From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH] add procfs tunable to enable immediate panic when there are busy inodes after umount Date: Wed, 30 May 2007 07:47:45 -0400 Message-ID: <20070530074745.15b8355b.jlayton@redhat.com> References: <20070529114042.5fe0b810.jlayton@redhat.com> <20070530002857.GW85884050@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: David Chinner Return-path: Received: from mx1.redhat.com ([66.187.233.31]:44932 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751595AbXE3Lrn (ORCPT ); Wed, 30 May 2007 07:47:43 -0400 In-Reply-To: <20070530002857.GW85884050@sgi.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, 30 May 2007 10:28:57 +1000 David Chinner wrote: > On Tue, May 29, 2007 at 11:40:42AM -0400, Jeff Layton wrote: > > After spending quite a bit of time tracking down a "VFS: busy inodes > > after unmount" problem, it occurs to me that it would be nice to be > > able to force a panic when that occurs. While an oops message alone is > > not generally helpful for tracking down this sort of problem, > > collecting and analyzing a coredump when this occurs can be. > > Agreed - we've found that we've had roughly 50% success in finding > the cause of these problems from crash dumps triggered immediately > like this vs ~0% from a crash that occurred some time later. > > Given that this problem will always result in a crash of the kernel > at some random time in the future, why don't we just make this error > an unconditional panic on get the crash over and done with? > Perhaps that's the best course of action. Then again, there can be a long time between the problem and crash (weeks even). For someone who can't collect a coredump, it might be preferable to not immediately crash the box and allow them to try to reboot it at a convenient time. That was my reasoning for adding the procfs tunable. Either way, if the machine doesn't crash immediately, I'd like to see a different error message here. The current one is confusing to users. They see it and figure "my box didn't crash in 5 mins, so everything must be OK!" -- Jeff Layton