[lxc-users] 'Failed to whiteout' error in Trusty with 3.19 kernel

[overlay fs]

> On Fri Aug 14 Thomas Müller wrote:
> Hi everyone,
>
> I'm running Ubuntu trusty and recently upgraded to the new kernel (3.19).
> When creating a snapshotted clone of a regular LXC container using
> overlayfs, I'm now seeing the kernel error 'failed to whiteout'.
>
> Has anyone experienced a similar problem, is this a known issue already?
>
> Below some debug information:
>
> - Kernel error: http://pastebin.com/iajXHbHZ
> - Kernel version: 3.19.0-25-generic #26~14.04.1-Ubuntu SMP Fri Jul 24
> 21:16:20 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
> - Executed LXC command: lxc-clone -s -B overlayfs orig test (both
> unprivileged containers)
> - LXC version: 1.0.7
>
> Any help/pointers would be appreciated.
>
> Best
> Thomas

I can reproduce the 'failed to whiteout' error message, though not the
kernel oops, in kvm.

It seems that the version of lxc in ubuntu-14.04 has an unstated dependency
upon kernel version <= 3.17 .  This will likely give rise to problems,
because ubuntu-14.04.3 ships with the 3.19 kernel.  Perhaps the lxc package
maintainer would add the kernel-dependency to ubuntu-14.04's lxc package?

The error message goes away when I upgrade to the daily build of lxc,
https://launchpad.net/~ubuntu-lxc/+archive/ubuntu/daily
<https://launchpad.net/%7Eubuntu-lxc/+archive/ubuntu/daily>

I haven't tested the more stable lxc versions at
https://launchpad.net/~ubuntu-lxc .

After upgrading lxc you may need to reboot and perhaps also to
destroy-and-recreate the overlayfs-backed container.

On a related matter, I would be interested to hear
whether you are affected by the overlayfs bug at,
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1480411

This bug affects unprivileged containers which use overlayfs in conjunction
with kernel 3.18+.
A script to test whether you are affected is attached to the bug report and
is also available at,
http://paste.ubuntu.com/11974137/

If you are affected, it would be helpful if you would add a comment to the
bug report,
since the bug status will then be changed to 'confirmed'.

-Oleg
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