From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752317AbbJSMr6 (ORCPT ); Mon, 19 Oct 2015 08:47:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:49642 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750904AbbJSMr4 (ORCPT ); Mon, 19 Oct 2015 08:47:56 -0400 Date: Mon, 19 Oct 2015 14:47:49 +0200 From: Jan Kara To: Ross Zwisler Cc: Jan Kara , linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara , Matthew Wilcox , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Dan Williams , Dave Chinner , "Kirill A. Shutemov" , linux-nvdimm@ml01.01.org, Matthew Wilcox Subject: Re: [PATCH v2 2/2] ext2: Add locking for DAX faults Message-ID: <20151019124749.GG25787@quack.suse.cz> References: <1444775137-23685-1-git-send-email-ross.zwisler@linux.intel.com> <1444775137-23685-3-git-send-email-ross.zwisler@linux.intel.com> <20151014085119.GB23758@quack.suse.cz> <20151014153138.GA12470@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151014153138.GA12470@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 14-10-15 09:31:38, Ross Zwisler wrote: > On Wed, Oct 14, 2015 at 10:51:19AM +0200, Jan Kara wrote: > > On Tue 13-10-15 16:25:37, Ross Zwisler wrote: > > > Add locking to ensure that DAX faults are isolated from ext2 operations > > > that modify the data blocks allocation for an inode. This is intended to > > > be analogous to the work being done in XFS by Dave Chinner: > > > > > > http://www.spinics.net/lists/linux-fsdevel/msg90260.html > > > > > > Compared with XFS the ext2 case is greatly simplified by the fact that ext2 > > > already allocates and zeros new blocks before they are returned as part of > > > ext2_get_block(), so DAX doesn't need to worry about getting unmapped or > > > unwritten buffer heads. > > > > > > This means that the only work we need to do in ext2 is to isolate the DAX > > > faults from inode block allocation changes. I believe this just means that > > > we need to isolate the DAX faults from truncate operations. > > > > > > The newly introduced dax_sem is intended to replicate the protection > > > offered by i_mmaplock in XFS. In addition to truncate the i_mmaplock also > > > protects XFS operations like hole punching, fallocate down, extent > > > manipulation IOCTLS like xfs_ioc_space() and extent swapping. Truncate is > > > the only one of these operations supported by ext2. > > > > > > Signed-off-by: Ross Zwisler > > > > The patch looks good to me. Feel free to add: > > > > Reviewed-by: Jan Kara > > > > Or I can push the patch through my tree as it seems to be independent of > > any other changes, am I right? > > > > Honza > > Yep, it is independent of other patches. It'd be great if you pushed it up > through your tree, thanks! I've pulled the patch into my tree and will push it to Linus in the next merge window. Honza -- Jan Kara SUSE Labs, CR