From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [RFC 0/9 v3] fsfreeze: miscellaneous fixes and cleanups Date: Fri, 14 Sep 2012 10:57:00 +1000 Message-ID: <20120914005700.GP11511@dastard> References: <1347533862.5646.2.camel@nexus.lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Al Viro , Josef Bacik , Eric Sandeen , Dave Chinner , Christoph Hellwig , Jan Kara , linux-fsdevel@vger.kernel.org To: Fernando Luis =?iso-8859-1?Q?V=E1zquez?= Cao Return-path: Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:22121 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754401Ab2INA5D (ORCPT ); Thu, 13 Sep 2012 20:57:03 -0400 Content-Disposition: inline In-Reply-To: <1347533862.5646.2.camel@nexus.lab.ntt.co.jp> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Sep 13, 2012 at 07:57:42PM +0900, Fernando Luis V=E1zquez Cao w= rote: > This patch set is to address long standing issues in the filesytem fr= eeze code > and to fill some functionality gaps in the API. Some minor code rearr= angements > are included too. >=20 > The following patches are included: >=20 > --- > [1/9] vfs: add __iterate_supers() helper > [2/9] fsfreeze: add unlocked version of thaw_super >=20 > Preparatory patches to fix s_umount lockup of emergency thaw code. >=20 > [3/9] fsfreeze: Prevent emergency thaw from looping infinitely >=20 > Fix thaw_bdev so that it propagates the error code properly to the ca= ller. > This bug caused emergency thaw to loop infinitely. This is a forward = port of > a previous patch by Dave Chinner. >=20 > [4/9] fsfreeze: emergency thaw will deadlock on s_umount >=20 > Avoid emergency thaw deadlock on s_umount by using unlocked version o= f > thaw_super() and __iterate_supers()i (introduced in patches 2 and 1 > respectively). Given the problems with emergency thaw, this interface has never really worked. In the absence of any obvious need for the functionality (i.e. nobody has reported that it is broken since it was introduced), why don't we simply remove it? IIRC, the emergency thaw code was only added to alleviate fear-mongering about systems getting stuck with unfreezable ext4 filesystems (after the "freeze w/ timeout" extensions were knocked back), and time has indicated those fears were unfounded. So, rather than trying to fix the emergency thaw mess, I say we nuke it from orbit.... 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