From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH 6/8] fsfreeze: add vfs ioctl to check freeze state Date: Thu, 13 Sep 2012 17:18:11 +1000 Message-ID: <20120913071810.GN11511@dastard> References: <1342083464.7033.6.camel@nexus.lab.ntt.co.jp> <1342084214.7033.16.camel@nexus.lab.ntt.co.jp> <20120713135454.GI20361@quack.suse.cz> <20120715224517.GD2920@dastard> <50517AEB.6060604@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Jan Kara , Al Viro , Dave Chinner , Christoph Hellwig , linux-fsdevel@vger.kernel.org To: Fernando Luis Vazquez Cao Return-path: Received: from ipmail05.adl6.internode.on.net ([150.101.137.143]:15046 "EHLO ipmail05.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755889Ab2IMHX5 (ORCPT ); Thu, 13 Sep 2012 03:23:57 -0400 Content-Disposition: inline In-Reply-To: <50517AEB.6060604@lab.ntt.co.jp> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Sep 13, 2012 at 03:19:23PM +0900, Fernando Luis Vazquez Cao wro= te: > On 2012/07/16 07:45, Dave Chinner wrote: > >On Fri, Jul 13, 2012 at 03:54:54PM +0200, Jan Kara wrote: > >>On Thu 12-07-12 18:10:14, Fernando Luis V=E1zquez Cao wrote: > >>>The FIISFROZEN ioctl can be use by HA and monitoring software to c= heck > >>>the freeze state of a mounted filesystem. > >Can you explain in more detail why the HA system needs to check this= ? > >And, for that matter, what it does with that information? >=20 > What our HA guys told me is that certain fencing scripts > try to umount filesystems that can be in frozen state. The > problem is that when we umount a frozen filesystem the > superblock still stays around which can lead to a split-brain > scenario. Then the bug is that unmounting a frozen filesystem is not working correctly. Fix the problem, don't add new APIs to try to detect a state where the bug might get tripped over and avoid it. Cheers, Dave. --=20 Dave Chinner david@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html