From: Theodore Tso Subject: Re: [PATCH] fix ext4_free_inode vs. ext4_claim_inode race Date: Wed, 4 Mar 2009 19:06:03 -0500 Message-ID: <20090305000603.GA30748@mit.edu> References: <49AE05D1.9050607@redhat.com> <20090304190659.GB17949@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Sandeen , ext4 development To: "Aneesh Kumar K.V" Return-path: Received: from THUNK.ORG ([69.25.196.29]:36486 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753682AbZCEAGL (ORCPT ); Wed, 4 Mar 2009 19:06:11 -0500 Content-Disposition: inline In-Reply-To: <20090304190659.GB17949@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Mar 05, 2009 at 12:36:59AM +0530, Aneesh Kumar K.V wrote: > On Tue, Mar 03, 2009 at 10:38:41PM -0600, Eric Sandeen wrote: > > I was seeing fsck errors on inode bitmaps after a 4 thread > > dbench run on a 4 cpu machine: > > > > Inode bitmap differences: -50736 -(50752--50753) etc... > > > > I believe that this is because ext4_free_inode() uses atomic > > bitops, and although ext4_new_inode() *used* to also use atomic > > bitops for synchronization, commit > > 393418676a7602e1d7d3f6e560159c65c8cbd50e changed this to use > > the sb_bgl_lock, so that we could also synchronize against > > read_inode_bitmap and initialization of uninit inode tables. > > > > However, that change left ext4_free_inode using atomic bitops, > > which I think leaves no synchronization between setting & > > unsetting bits in the inode table. > > > > The below patch fixes it for me, although I wonder if we're > > getting at all heavy-handed with this spinlock... > > > > Signed-off-by: Eric Sandeen > > Reviewed-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" Added to the ext4 patch queue. I will push this to Linus after I do a bit of testing. - Ted