From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84AB8C43334 for ; Mon, 20 Jun 2022 00:21:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236587AbiFTAVb (ORCPT ); Sun, 19 Jun 2022 20:21:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232286AbiFTAVa (ORCPT ); Sun, 19 Jun 2022 20:21:30 -0400 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CD9C7958F for ; Sun, 19 Jun 2022 17:21:28 -0700 (PDT) Received: from dread.disaster.area (pa49-181-2-147.pa.nsw.optusnet.com.au [49.181.2.147]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id AC98510E78EA; Mon, 20 Jun 2022 10:21:27 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1o35AU-008i8T-5i; Mon, 20 Jun 2022 10:21:26 +1000 Date: Mon, 20 Jun 2022 10:21:26 +1000 From: Dave Chinner To: Alli Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH v1 14/17] xfs: Add the parent pointer support to the superblock version 5. Message-ID: <20220620002126.GM227878@dread.disaster.area> References: <20220611094200.129502-1-allison.henderson@oracle.com> <20220611094200.129502-15-allison.henderson@oracle.com> <20220616060310.GE227878@dread.disaster.area> <3d1cdf9bdf67954c457077a58b6520f609999b57.camel@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3d1cdf9bdf67954c457077a58b6520f609999b57.camel@oracle.com> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=VuxAv86n c=1 sm=1 tr=0 ts=62afbd88 a=ivVLWpVy4j68lT4lJFbQgw==:117 a=ivVLWpVy4j68lT4lJFbQgw==:17 a=kj9zAlcOel0A:10 a=JPEYwPQDsx4A:10 a=eJfxgxciAAAA:8 a=20KFwNOVAAAA:8 a=yPCof4ZbAAAA:8 a=7-415B0cAAAA:8 a=ofUXJsk1A2IqffOnco8A:9 a=CjuIK1q_8ugA:10 a=xM9caqqi1sUkTy8OJ5Uh:22 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Jun 17, 2022 at 05:32:36PM -0700, Alli wrote: > On Thu, 2022-06-16 at 16:03 +1000, Dave Chinner wrote: > > On Sat, Jun 11, 2022 at 02:41:57AM -0700, Allison Henderson wrote: > > > [dchinner: forward ported and cleaned up] > > > [achender: rebased and added parent pointer attribute to > > > compatible attributes mask] > > > > > > Signed-off-by: Mark Tinguely > > > Signed-off-by: Dave Chinner > > > Signed-off-by: Allison Henderson > > > Reviewed-by: Darrick J. Wong > > > --- > > > fs/xfs/libxfs/xfs_format.h | 14 +++++++++----- > > > fs/xfs/libxfs/xfs_fs.h | 1 + > > > fs/xfs/libxfs/xfs_sb.c | 2 ++ > > > fs/xfs/xfs_super.c | 4 ++++ > > > 4 files changed, 16 insertions(+), 5 deletions(-) > > > > > > diff --git a/fs/xfs/libxfs/xfs_format.h > > > b/fs/xfs/libxfs/xfs_format.h > > > index 96976497306c..e85d6b643622 100644 > > > --- a/fs/xfs/libxfs/xfs_format.h > > > +++ b/fs/xfs/libxfs/xfs_format.h > > > @@ -83,6 +83,7 @@ struct xfs_ifork; > > > #define XFS_SB_VERSION2_OKBITS \ > > > (XFS_SB_VERSION2_LAZYSBCOUNTBIT | \ > > > XFS_SB_VERSION2_ATTR2BIT | \ > > > + XFS_SB_VERSION2_PARENTBIT | \ > > > XFS_SB_VERSION2_PROJID32BIT | \ > > > XFS_SB_VERSION2_FTYPE) > > > > No need for a v4 filesystem format feature bit - this is v4 only. > Ok, I ended up having to add this in the rebase or we get an "SB > validate failed". I think it has to go over in > xfs_sb_validate_v5_features next to the manual crc bit check. Will > move Ah, I meant that parent pointers are a v5 only feature, and so we don't need a "v4 only" feature bit for it. As it is, we can't use that specific bit because SGI shipped a version of parent pointers on v4 filesystems on IRIX under that feature bit that was broken and subsequently recalled and killed. Essentially, that means XFS_SB_VERSION2_PARENTBIT is blacklisted and cannot ever be used by upstream kernels. > > > @@ -353,11 +354,13 @@ xfs_sb_has_compat_feature( > > > #define XFS_SB_FEAT_RO_COMPAT_RMAPBT (1 << 1) /* > > > reverse map btree */ > > > #define XFS_SB_FEAT_RO_COMPAT_REFLINK (1 << 2) /* > > > reflinked files */ > > > #define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3) /* > > > inobt block counts */ > > > +#define XFS_SB_FEAT_RO_COMPAT_PARENT (1 << 4) /* > > > parent inode ptr */ > > > #define XFS_SB_FEAT_RO_COMPAT_ALL \ > > > - (XFS_SB_FEAT_RO_COMPAT_FINOBT | \ > > > - XFS_SB_FEAT_RO_COMPAT_RMAPBT | \ > > > - XFS_SB_FEAT_RO_COMPAT_REFLINK| \ > > > - XFS_SB_FEAT_RO_COMPAT_INOBTCNT) > > > + (XFS_SB_FEAT_RO_COMPAT_FINOBT | \ > > > + XFS_SB_FEAT_RO_COMPAT_RMAPBT | \ > > > + XFS_SB_FEAT_RO_COMPAT_REFLINK | \ > > > + XFS_SB_FEAT_RO_COMPAT_INOBTCNT| \ > > > + XFS_SB_FEAT_RO_COMPAT_PARENT) > > > > I'm not sure this is a RO Compat feature - we added an attribute > > namespace flag on disk, and the older kernels do not know about > > that (i.e. we changed XFS_ATTR_NSP_ONDISK_MASK). This may result in > > parent pointer attrs being exposed as user attrs rather than being > > hidden, or maybe parent pointer attrs being seen as corrupt because > > they have a flag that isn't defined set, etc. > > > > Hence I'm not sure that this classification is correct. > > Gosh, I'm sure there was a reason we did this, but what ever it was > goes all the way back in the first re-appearance of the set back in > 2018 and I just cant remember the discussion at the time. It may have > just been done to get mkfs working and we just never got to reviewing > it. > > Should we drop it and just use XFS_SB_VERSION2_PARENTBIT? No, it needs to be a v5 feature bit - create a v5 parent pointer filesystem, create some files on it, and then go an mount it on a kernel that doesn't have PP support. If you can see the parent pointer attributes from userspace as "user." attributes, then we need to use an INCOMPAT feature bit rather than a RO_COMPAT bit. Cheers, Dave. -- Dave Chinner david@fromorbit.com