From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:42204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727031AbeKHI2z (ORCPT ); Thu, 8 Nov 2018 03:28:55 -0500 Date: Wed, 7 Nov 2018 17:56:20 -0500 From: Sasha Levin To: Amir Goldstein Cc: "Darrick J. Wong" , Dave Chinner , Eryu Guan , Greg KH , stable , linux-xfs , linux-fsdevel , Brian Foster , Sasha Levin Subject: Re: [PATCH] xfs: truncate transaction does not modify the inobt Message-ID: <20181107225620.GD2644@sasha-vm> References: <20181103171524.2740-1-amir73il@gmail.com> <20181107051821.GZ4135@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Nov 07, 2018 at 07:31:31AM +0200, Amir Goldstein wrote: >On Wed, Nov 7, 2018 at 7:18 AM Darrick J. Wong wrote: >> >> 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 > >I agree, as these error messages try to express: >[ 4.982926] XFS (vdd): EXPERIMENTAL reverse mapping btree feature >enabled. Use at your own risk! >[ 4.984843] XFS (vdd): EXPERIMENTAL reflink feature enabled. Use at >your own risk! >[ 4.987259] XFS (vdd): Log size 3693 blocks too small, minimum size >is 4473 blocks > >But it is still a regression, because as I understand some where using >reflink back from >stable 4.9, while it was still maintained... > >> >> That said... does it change the minimum log size for (finobt, !reflink, >> !rmap) filesystems? That might be a bigger worry. I /think/ the > >No problem on my systems mounting small fs with (finobt, !reflink,!rmap) >formatted with mkfs.xfs 4.18. > >> transaction reservation change is fine, though I defer to Amir on >> testing... :) >> > >Testing passed as I wrote, for configs 4k,1k,reflink,reflink+overlay. > >Sasha, please consider the fix patch for 4.14.y,4.9.y. Queued for 4.9 and 4.14, thank you. -- Thanks, Sasha