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Date: Mon, 23 Jan 2017 13:31:09 -0800
From: Omar Sandoval <osandov@osandov.com>
To: Chris Murphy <lists@colorremedies.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>, agruenba@redhat.com
Subject: Re: read-only fs, kernel 4.9.0, fs/btrfs/delayed-inode.c:1170
 __btrfs_run_delayed_items,
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On Wed, Jan 18, 2017 at 02:27:13PM -0700, Chris Murphy wrote:
> On Wed, Jan 11, 2017 at 4:13 PM, Chris Murphy <lists@colorremedies.com> wrote:
> > Looks like there's some sort of xattr and Btrfs interaction happening
> > here; but as it only happens with some subvolumes/snapshots not all
> > (but 100% consistent) maybe the kernel version at the time the
> > snapshot was taken is a factor?
> 
> The kernel version at the time the snapshot is taken is not a factor.
> I've taken a snapshot of a working subvolume, and booting the snapshot
> fails during startup with the fs forced readonly with kernel 4.9 and
> higher; the problem doesn't happen with kernel 4.8.17 and lower.
> 
> As a further test I tried:
> 
> 
> git checkout tags/v4.9
> git revert 6c6ef9f26e598fb977f60935e109cd5b266c941a
> 
> But I get a failure during compile:
> 
> scripts/Makefile.build:293: recipe for target 'fs/xattr.o' failed
> make[1]: *** [fs/xattr.o] Error 1
> Makefile:988: recipe for target 'fs' failed
> make: *** [fs] Error 2
> 
> Anyway, the inability to boot snapshots means bootable rollbacks are
> broken. I think this is a serious regression, what's the next step in
> figuring out what's going on?

Hm, so you're 100% sure that this exact commit caused the regression?
I've stared at it for a little while and am not seeing anything obvious.