From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail01.adl6.internode.on.net ([150.101.137.136]:9874 "EHLO ipmail01.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbdH3ILJ (ORCPT ); Wed, 30 Aug 2017 04:11:09 -0400 Date: Wed, 30 Aug 2017 18:10:30 +1000 From: Dave Chinner Subject: Re: [PATCH] xfs: skip free eofblocks if inode is under written back Message-ID: <20170830081030.GL10621@dastard> References: <20170830042628.5592-1-eguan@redhat.com> <20170830072950.GJ10621@dastard> <20170830075109.GA4711@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170830075109.GA4711@infradead.org> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Christoph Hellwig Cc: Eryu Guan , linux-xfs@vger.kernel.org On Wed, Aug 30, 2017 at 12:51:09AM -0700, Christoph Hellwig wrote: > On Wed, Aug 30, 2017 at 05:29:50PM +1000, Dave Chinner wrote: > > Quick patch below, doesn't work on reflink filesystems yet because > > the way it handles cached COW mapping invalidation is unnecessarily > > special and so doesn't work. Can you test it and see if it fixes the > > problem? > > FYI, I thought about this problem a while ago in the context of > rcu lookups of the extent tree (not, I'm not doing those quite yet, > but I though of the possibilities once we've got a btree!) and > then my answer was that we'd really need a seqlock around uses of > the imaps. I didn't think far enough that we might need something > like that even now.. Now that you mention it, a seqlock is probably a pretty good fit for this. I'll have a look at it tomorrow.... Cheers, Dave. -- Dave Chinner david@fromorbit.com