From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:26921 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1036135AbdD2XCJ (ORCPT ); Sat, 29 Apr 2017 19:02:09 -0400 Date: Sun, 30 Apr 2017 09:01:59 +1000 From: Dave Chinner To: Amir Goldstein Cc: Miklos Szeredi , "Darrick J . Wong" , Christoph Hellwig , Theodore Ts'o , Jaegeuk Kim , Mark Fasheh , Al Viro , linux-xfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 0/5] VFS API for getting filesystem's UUID Message-ID: <20170429230159.GM12369@dastard> References: <1493283574-1497-1-git-send-email-amir73il@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1493283574-1497-1-git-send-email-amir73il@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Apr 27, 2017 at 11:59:29AM +0300, Amir Goldstein wrote: > Miklos, > > As you observed, the sb->s_uuid field is not always filled by filesystems. > > Consumers, like overlayfs, that wish to use this field can check if is > zeroed out as an indication for valid value. > > Christoph suggested to make the test more explicit and require the > filesystems that fill the s_uuid field to set a super block flag. > > Do you agree with the proposed API? > > The first patch in the series defines the flag. > If you push this patch through your tree to Al or Linus, then filesystem > maintainers could later pick the individual patches to their trees. > > The xfs patch is based on a patch I already sent to Darrick for filling > out the s_uuid field. > > Thanks, > Amir. > > Amir Goldstein (5): > vfs: define a flag to indicate sb->s_uuid is available > ext4: set the super block SB_I_HAVE_UUID flag > f2fs: set the super block SB_I_HAVE_UUID flag > ocfs2: set the super block SB_I_HAVE_UUID flag > xfs: set the super block SB_I_HAVE_UUID flag > > fs/ext4/super.c | 1 + > fs/f2fs/super.c | 1 + > fs/ocfs2/super.c | 1 + > fs/xfs/xfs_mount.c | 1 + > include/linux/fs.h | 3 +++ > 5 files changed, 7 insertions(+) Doesn't this make the struct export_opierations .get_uuid method somewhat redundant? Shouldn't that now be replaced with generic functions that looks at SB_I_HAVE_UUID before allowing PNFS export is allowed and then just use s_uuid directly in the PNFS code? Cheers, Dave. -- Dave Chinner david@fromorbit.com