From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: [PATCH 0/3] DAX: Fix mmap-write not updating c/mtime Date: Wed, 04 Mar 2015 18:33:01 +0200 Message-ID: <54F733BD.7060807@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Dave Chinner , Matthew Wilcox , Andrew Morton , "Kirill A. Shutemov" , Jan Kara , Hugh Dickins , Mel Gorman , linux-mm@kvack.org, linux-nvdimm , linux-fsdevel Return-path: Received: from mail-wg0-f42.google.com ([74.125.82.42]:43824 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759026AbbCDQdF (ORCPT ); Wed, 4 Mar 2015 11:33:05 -0500 Received: by wggy19 with SMTP id y19so47793321wgg.10 for ; Wed, 04 Mar 2015 08:33:04 -0800 (PST) Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hi First submitted an xfstest (generic/080) that demonstrates our current problem. When run on ext4-dax mount, and I'd imagine Dave's xfs-dax mount this test fails, on regular mount it works just fine. then 2 patches to fix it. The main problem is that current mm/memory.c will no call us with page_mkwrite if we do not have an actual page mapping, which is what DAX uses. The solution presented here introduces a new pfn_mkwrite to solve this problem. Please see patch-2 for details. I've been running with this patch for 4 month both HW and VMs with no apparent danger, but see patch-2 I played it safe. List of patches: [PATCH 1/2] generic: 080 test that mmap-write updates c/mtime This one is for Dave Chinner to submit to xfstests [PATCH 1/2] mm: New pfn_mkwrite same as page_mkwrite for VM_PFNMAP This patch I need help with please look into it? [PATCH 2/2] dax: use pfn_mkwrite to update mtime Please review and comment. Thanks Boaz