From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:50168 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751085AbdING5o (ORCPT ); Thu, 14 Sep 2017 02:57:44 -0400 Date: Thu, 14 Sep 2017 14:57:41 +0800 From: Eryu Guan Subject: Re: [fstests PATCH v2] xfs: add regression test for DAX mount option usage Message-ID: <20170914065741.GH8034@eguan.usersys.redhat.com> References: <20170911200103.28226-1-ross.zwisler@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170911200103.28226-1-ross.zwisler@linux.intel.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Ross Zwisler Cc: fstests@vger.kernel.org, Jan Kara , "Darrick J. Wong" , linux-nvdimm@lists.01.org, Dave Chinner , Christoph Hellwig , linux-xfs@vger.kernel.org, Dan Williams Hi Ross, On Mon, Sep 11, 2017 at 02:01:03PM -0600, Ross Zwisler wrote: > This adds a regression test for the following kernel patch: > > xfs: always use DAX if mount option is used > > This test will also pass with kernel v4.14-rc1 and beyond because the XFS > DAX I/O mount option has been disabled (but not removed), so the > "chattr -x" to turn off DAX doesn't actually do anything. > > Signed-off-by: Ross Zwisler > Suggested-by: Christoph Hellwig > --- > > Changes since v1: > - Use perf instead of tracepoints to detect whether DAX is used. (Dan) Thanks for the test! But I agreed with Dave here, it doesn't seem like a good idea to depend on the kernel tracepoints in a test, but I can't think of a better solution either, so I didn't get to this patch earlier.. Before XFS disabled the ability to switch on & off per-inode DAX flag, the x flag was only shown after an explicit 'chattr +x', even if XFS was mounted with dax option, e.g. # mkfs -t xfs -f /dev/ram0 # mount -o dax /dev/ram0 /mnt/xfs # echo "test" > /mnt/xfs/testfile # xfs_io -c "lsattr" /mnt/xfs/testfile ---------------- /mnt/xfs/testfile # xfs_io -c "chattr +x" /mnt/xfs/testfile # xfs_io -c "lsattr" /mnt/xfs/testfile ---------------x /mnt/xfs/testfile I'm wondering if it makes sense to make lsattr print the x flag by default when XFS is mounted with dax option, that way, we have a method to know whether dax is used or not on a particular file too. Thanks, Eryu