From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 24 Jan 2007 06:41:11 -0800 (PST) Received: from amsfep11-int.chello.nl (amsfep19-int.chello.nl [213.46.243.16] (may be forged)) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l0OEf2qw022475 for ; Wed, 24 Jan 2007 06:41:04 -0800 Subject: Re: [PATCH 1/2]: Fix BUG in cancel_dirty_pages on XFS From: Peter Zijlstra In-Reply-To: <45B7627B.8050202@yahoo.com.au> References: <20070123223702.GF33919298@melbourne.sgi.com> <1169640835.6189.14.camel@twins> <45B7627B.8050202@yahoo.com.au> Content-Type: text/plain Date: Wed, 24 Jan 2007 15:40:04 +0100 Message-Id: <1169649604.6189.27.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Nick Piggin Cc: David Chinner , linux-kernel@vger.kernel.org, xfs@oss.sgi.com, akpm@osdl.org On Thu, 2007-01-25 at 00:43 +1100, Nick Piggin wrote: > > Have you seen the new launder_page() a_op? called from > > invalidate_inode_pages2_range() > > It would have been nice to make that one into a more potentially > useful generic callback. That can still be done when the need arises, right? > But why was it introduced, exactly? I can't tell from the code or > the discussion why NFS couldn't start the IO, and signal the caller > to wait_on_page_writeback and retry? That seemed to me like the > convetional fix. to quote a bit: On Tue, 19 Dec 2006 18:19:38 -0500 Trond Myklebust wrote: > NFS: Fix race in nfs_release_page() > > invalidate_inode_pages2() may set the dirty bit on a page owing to the call > to unmap_mapping_range() after the page was locked. In order to fix this, > NFS has hooked the releasepage() method. This, however leads to deadlocks > in other parts of the VM. and: > > Now, arguably the VM shouldn't be calling try_to_release_page() with > > __GFP_FS when it's holding a lock on a page. > > > > But otoh, NFS should never be running lock_page() within nfs_release_page() > > against the page which was passed into nfs_release_page(). It'll deadlock > > for sure. > > The reason why it is happening is that the last dirty page from that > inode gets cleaned, resulting in a call to dput().