From: Mike Snitzer Subject: Re: [PATCH 2/2] dm log writes: add support for DAX Date: Tue, 24 Oct 2017 15:22:23 -0400 Message-ID: <20171024192222.GB22902@redhat.com> References: <20171020052404.13762-1-ross.zwisler@linux.intel.com> <20171020052404.13762-2-ross.zwisler@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jan Kara , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, Josef Bacik , Dave Chinner , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Christoph Hellwig , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shaohua Li , Alasdair Kergon To: Ross Zwisler Return-path: Content-Disposition: inline In-Reply-To: <20171020052404.13762-2-ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On Fri, Oct 20 2017 at 1:24am -0400, Ross Zwisler wrote: > Now that we have the ability log filesystem writes using a flat buffer, add > support for DAX. Unfortunately we can't easily track data that has been > written via mmap() now that the dax_flush() abstraction was removed by this > commit: > > commit c3ca015fab6d ("dax: remove the pmem_dax_ops->flush abstraction") > > Otherwise we could just treat each flush as a big write, and store the data > that is being synced to media. It may be worthwhile to add the dax_flush() > entry point back, just as a notifier so we can do this logging. > > The motivation for this support is the need for an xfstest that can test > the new MAP_SYNC DAX flag. By logging the filesystem activity with > dm-log-writes we can show that the MAP_SYNC page faults are writing out > their metadata as they happen, instead of requiring an explicit > msync/fsync. > > Signed-off-by: Ross Zwisler I've picked this up, please see: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=for-4.15/dm&id=ae613bbb0144e84cb3c0ebfa9f4fd4d1507c2f0e I tweaked the header and tweaked a couple whitespace nits. Also switched version bump from 1.0.1 to 1.1.0. Thanks, Mike