From: Ross Zwisler Subject: Re: [PATCH] ext4: allow DAX writeback for hole punch Date: Wed, 17 Aug 2016 12:07:22 -0600 Message-ID: <20160817180722.GB16779@linux.intel.com> References: <20160817161102.2185-1-ross.zwisler@linux.intel.com> <20160817171955.GA30893@quack2.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Theodore Ts'o , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andreas Dilger , Jan Kara , linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jan Kara Return-path: Content-Disposition: inline In-Reply-To: <20160817171955.GA30893-4I4JzKEfoa/jFM9bn6wA6Q@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 Wed, Aug 17, 2016 at 07:19:55PM +0200, Jan Kara wrote: > On Wed 17-08-16 10:11:02, Ross Zwisler wrote: > > Currently when doing a DAX hole punch with ext4 we fail to do a writeback. > > This is because the logic around filemap_write_and_wait_range() in > > ext4_punch_hole() only looks for dirty page cache pages in the radix tree, > > not for dirty DAX exceptional entries. > > > > Signed-off-by: Ross Zwisler > > Thanks. The patch looks correct, you can add: > > Reviewed-by: Jan Kara > > Although why don't we just simplify the test below to > mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)? After all the mapping should > not have the dirty tag set if there are no pages / no entries? Sure, that works. I'll update to that in V2, and I'll add stable. Thanks!