From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Zwisler Subject: Re: [PATCH] dax: fix deadlock in __dax_fault Date: Fri, 25 Sep 2015 12:23:34 -0600 Message-ID: <20150925182334.GA26544@linux.intel.com> References: <1443040800-5460-1-git-send-email-ross.zwisler@linux.intel.com> <20150924025225.GT3902@dastard> <20150924155029.GA6008@linux.intel.com> <20150925025357.GU3902@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ross Zwisler , linux-kernel@vger.kernel.org, Alexander Viro , Matthew Wilcox , linux-fsdevel@vger.kernel.org, Andrew Morton , Dan Williams , "Kirill A. Shutemov" , linux-nvdimm@lists.01.org To: Dave Chinner Return-path: Received: from mga09.intel.com ([134.134.136.24]:43592 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932994AbbIYSXf (ORCPT ); Fri, 25 Sep 2015 14:23:35 -0400 Content-Disposition: inline In-Reply-To: <20150925025357.GU3902@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Sep 25, 2015 at 12:53:57PM +1000, Dave Chinner wrote: <> > We've already got block allocation serialisation at the filesystem > level, and the issue is the unserialised block zeroing being done by > the dax code. That can be fixed by moving the zeroing into the > filesystem code when it runs "complete_unwritten" and checks whether > the mapping has already been marked as written or not... > > I've recently pointed out in a different thread that this is the > solution to whatever that problem was (can't recall which > thread/problem is was now :/ ) and it the same solution here. We > already have the serialisation we need, we just need to move the > block zeroing operation into the appropriate places to make it work > correctly. I think perhaps this is the thread that you're remembering: https://lkml.org/lkml/2015/8/11/731