From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2120.oracle.com ([141.146.126.78]:43774 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727178AbeKGOrT (ORCPT ); Wed, 7 Nov 2018 09:47:19 -0500 Date: Tue, 6 Nov 2018 21:18:21 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH] xfs: truncate transaction does not modify the inobt Message-ID: <20181107051821.GZ4135@magnolia> References: <20181103171524.2740-1-amir73il@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Amir Goldstein Cc: Dave Chinner , Eryu Guan , Greg KH , stable , linux-xfs , linux-fsdevel , Brian Foster , Sasha Levin On Wed, Nov 07, 2018 at 07:09:42AM +0200, Amir Goldstein wrote: > On Mon, Nov 5, 2018 at 7:57 PM Amir Goldstein wrote: > > > > On Sat, Nov 3, 2018 at 7:15 PM Amir Goldstein wrote: > > > > > > From: Brian Foster > > > > > > The truncate transaction does not ever modify the inode btree, but > > > includes an associated log reservation. Update > > > xfs_calc_itruncate_reservation() to remove the reservation > > > associated with inobt updates. > > > > > > [Amir: This commit was merged for kernel v4.16 and a twin commit was > > > merged for xfsprogs v4.16. As a result, a small xfs filesystem > > > formatted with features -m rmapbt=1,reflink=1 using mkfs.xfs > > > version >= v4.16 cannot be mounted with kernel < v4.16. > > > > > > For example, xfstests generic/17{1,2,3} format a small fs and > > > when trying to mount it, they fail with an assert on this very > > > demonic line: > > > > > > XFS (vdc): Log size 3075 blocks too small, minimum size is 3717 blocks > > > XFS (vdc): AAIEEE! Log failed size checks. Abort! > > > XFS: Assertion failed: 0, file: src/linux/fs/xfs/xfs_log.c, line: 666 > > > > > > The simple solution for stable kernels is to apply this patch, > > > because mkfs.xfs v4.16 is already in the wild, so we have to > > > assume that xfs filesystems with a "too small" log exist. > > > Regardless, xfsprogs maintainers should also consider reverting > > > the twin patch to stop creating those filesystems for the sake > > > of users with unpatched kernels.] > > > > > > Signed-off-by: Brian Foster > > > Reviewed-by: Dave Chinner > > > Reviewed-by: Darrick J. Wong > > > Signed-off-by: Darrick J. Wong > > > Cc: # v4.9+ > > > Signed-off-by: Amir Goldstein > > > --- > > > > > > Darrick/Dave, > > > > > > It took me a while to figure out what was going on with my test systems > > > when small test partitions (10G) stopped working with older kernels. > > > > > > Please bless this change for stable and consider the remedie for mkfs.xfs > > > I verified that patch cleanly applies to stable kernels 4.14.y and 4.9.y > > > and that I can mount a filsystem created with new mkfs.xfs. > > > > > > I am now running quick tests on stable 4.14.y with configs 4k, 1k, > > > reflink,reflink+overlay to verify no regressions from this patch. > > > > > > > FYI no regressions detected. > > > > Thoughts? > > > > Maybe you'd want to chalk it up to reflink/rmapbt being Experimental > before kernel 4.16? so the change in "minimum log size" is an on-disk format > change prior to removing the Experimental label?? TBH nobody should be using reflink/rmap on 4.14 kernels, ever. :D That said... does it change the minimum log size for (finobt, !reflink, !rmap) filesystems? That might be a bigger worry. I /think/ the transaction reservation change is fine, though I defer to Amir on testing... :) --D > Thanks, > Amir.