From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36226 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932136AbeCKQYl (ORCPT ); Sun, 11 Mar 2018 12:24:41 -0400 Date: Sun, 11 Mar 2018 17:24:42 +0100 From: Greg KH Subject: Re: [PATCH v2] xfs: preserve i_rdev when recycling a reclaimable inode Message-ID: <20180311162442.GB2013@kroah.com> References: <1516952669-14769-1-git-send-email-amir73il@gmail.com> <20180126214404.GE9068@magnolia> <20180129155054.GJ9359@magnolia> <20180201003511.GK4849@magnolia> 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: "Darrick J. Wong" , Christoph Hellwig , Eryu Guan , Miklos Szeredi , linux-xfs , linux-fsdevel , stable@kernel.org On Sun, Mar 11, 2018 at 06:08:06PM +0200, Amir Goldstein wrote: > On Thu, Feb 1, 2018 at 2:35 AM, Darrick J. Wong wrote: > > On Thu, Feb 01, 2018 at 02:27:23AM +0200, Amir Goldstein wrote: > >> On Mon, Jan 29, 2018 at 5:50 PM, Darrick J. Wong > >> wrote: > >> > On Mon, Jan 29, 2018 at 01:07:36PM +0200, Amir Goldstein wrote: > >> >> On Fri, Jan 26, 2018 at 11:44 PM, Darrick J. Wong > >> >> wrote: > >> >> > On Fri, Jan 26, 2018 at 09:44:29AM +0200, Amir Goldstein wrote: > >> >> >> Commit 66f364649d870 ("xfs: remove if_rdev") moved storing of rdev > >> >> >> value for special inodes to VFS inodes, but forgot to preserve the > >> >> >> value of i_rdev when recycling a reclaimable xfs_inode. > >> >> >> > >> >> >> This was detected by xfstest overlay/017 with inodex=on mount option > >> >> >> and xfs base fs. The test does a lookup of overlay chardev and blockdev > >> >> >> right after drop caches. > >> >> >> > >> >> >> Overlayfs inodes hold a reference on underlying xfs inodes when mount > >> >> >> option index=on is configured. If drop caches reclaim xfs inodes, before > >> >> >> it relclaims overlayfs inodes, that can sometimes leave a reclaimable xfs > >> >> >> inode and that test hits that case quite often. > >> >> >> > >> >> >> When that happens, the xfs inode cache remains broken (zere i_rdev) > >> >> >> until the next cycle mount or drop caches. > >> >> >> > >> >> >> Fixes: 66f364649d870 ("xfs: remove if_rdev") > >> >> >> Signed-off-by: Amir Goldstein > >> >> > > >> >> > Looks ok, > >> >> > Reviewed-by: Darrick J. Wong > >> >> > > >> >> > >> >> I recon that now we should now also strap: > >> >> Cc: #v4.15 > >> >> > >> >> Can I assume, you'll add it on apply? > >> > > >> > I'll do a proper backport of this and a couple other critical cow > >> > fixes after I get the 4.16 stuff merged. > >> > > >> > >> I am not sure what "proper backport" means in the context of > >> this patch. > >> This is a v4.15-rc1 regression fix that is based on v4.15-rc8. > >> It applied cleanly on v4.15. > > > > I meant the other things that went into 4.16, like the reflink quota > > fixes, the directio corruption problems, etc. Make a branch, add the > > necessary fixes, run xfstests to make sure it all still works, etc. > > > > Darrick, > > I may be missing something in the process of stable kernel > maintenance, but this patch fixes a reproducible v4.15 regression > (xfstest overlay/017 fails on stable kernel v4.15). > > Is Greg usually picking those stable patches himself or is he waiting > for xfs maintainers (or xfs stable maintainers) to stage the > stable patches? I'm waiting for the patch to either be tagges with cc: stable, or for someone to tell me to take the patch. Sometimes I dig through the tree, but for xfs patches, I do not, as was told not to :) thanks, greg k-h