From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757912AbcLAHyD (ORCPT ); Thu, 1 Dec 2016 02:54:03 -0500 Received: from mx2.suse.de ([195.135.220.15]:34662 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750847AbcLAHyB (ORCPT ); Thu, 1 Dec 2016 02:54:01 -0500 Date: Thu, 1 Dec 2016 08:53:56 +0100 From: Jan Kara To: Ross Zwisler Cc: Jan Kara , linux-kernel@vger.kernel.org, Alexander Viro , Andrew Morton , Christoph Hellwig , Dan Williams , Dave Chinner , Ingo Molnar , Matthew Wilcox , Steven Rostedt , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@ml01.01.org Subject: Re: [PATCH 1/6] dax: fix build breakage with ext4, dax and !iomap Message-ID: <20161201075356.GA12804@quack2.suse.cz> References: <1479926662-21718-1-git-send-email-ross.zwisler@linux.intel.com> <1479926662-21718-2-git-send-email-ross.zwisler@linux.intel.com> <20161124090239.GA24138@quack2.suse.cz> <20161128191504.GB6637@linux.intel.com> <20161129085303.GA7550@quack2.suse.cz> <20161130190431.GA11793@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161130190431.GA11793@linux.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 30-11-16 12:04:31, Ross Zwisler wrote: > On Tue, Nov 29, 2016 at 09:53:03AM +0100, Jan Kara wrote: > > On Mon 28-11-16 12:15:04, Ross Zwisler wrote: > > > On Thu, Nov 24, 2016 at 10:02:39AM +0100, Jan Kara wrote: > > > > On Wed 23-11-16 11:44:17, Ross Zwisler wrote: > > > > > With the current Kconfig setup it is possible to have the following: > > > > > > > > > > CONFIG_EXT4_FS=y > > > > > CONFIG_FS_DAX=y > > > > > CONFIG_FS_IOMAP=n # this is in fs/Kconfig & isn't user accessible > > > > > > > > > > With this config we get build failures in ext4_dax_fault() because the > > > > > iomap functions in fs/dax.c are missing: > > > > > > > > > > fs/built-in.o: In function `ext4_dax_fault': > > > > > file.c:(.text+0x7f3ac): undefined reference to `dax_iomap_fault' > > > > > file.c:(.text+0x7f404): undefined reference to `dax_iomap_fault' > > > > > fs/built-in.o: In function `ext4_file_read_iter': > > > > > file.c:(.text+0x7fc54): undefined reference to `dax_iomap_rw' > > > > > fs/built-in.o: In function `ext4_file_write_iter': > > > > > file.c:(.text+0x7fe9a): undefined reference to `dax_iomap_rw' > > > > > file.c:(.text+0x7feed): undefined reference to `dax_iomap_rw' > > > > > fs/built-in.o: In function `ext4_block_zero_page_range': > > > > > inode.c:(.text+0x85c0d): undefined reference to `iomap_zero_range' > > > > > > > > > > Now that the struct buffer_head based DAX fault paths and I/O path have > > > > > been removed we really depend on iomap support being present for DAX. Make > > > > > this explicit by selecting FS_IOMAP if we compile in DAX support. > > > > > > > > > > Signed-off-by: Ross Zwisler > > > > > > > > I've sent the same patch to Ted yesterday and he will probably queue it on > > > > top of ext4 iomap patches. If it doesn't happen for some reason, feel free > > > > to add: > > > > > > > > Reviewed-by: Jan Kara > > > > > > Cool, looks like Ted has pulled in your patch. > > > > > > I think we still eventually want this patch because it cleans up our handling > > > of FS_IOMAP. With your patch we select it separately in both ext4 & ext2 > > > based on whether we include DAX, and we still have #ifdefs in fs/dax.c for > > > FS_IOMAP. > > > > Actually, based on Dave's request I've also sent Ted updated version which > > did select FS_IOMAP in CONFIG_DAX section. However Ted didn't pull that > > patch (yet?). Anyway, I don't care whose patch gets merged, I just wanted > > to notify you of possible conflict. > > Can you please CC me on these patches in the future? I also don't care whose > patches end up fixing this, but I want to make sure we end up in a world where > the "select FS_IOMAP" just happens directly for FS_DAX in fs/Kconfig so that > I can get rid of the unnecessary #ifdefs in fs/dax.c for CONFIG_FS_IOMAP. Sure, will do. Honza -- Jan Kara SUSE Labs, CR