[lxc-users] Bug report: unprivileged containers with btrfs backingstore

[overlay fs]

These two bugs occur only for containers with a btrfs backingstore.

First, create a container with a btrfs backingstore:

$lxc-create -B btrfs -t download -n p1 -- -d ubuntu -r trusty -a amd64

Bug (1): cloned rootfs has wrong ownership:
$lxc-clone -s -o p1 -n p1_clone
$ls -ld p1_clone/rootfs p1/rootfs:
drwxr-xr-x 1 100000 200000 162 May 27  2015 p1_clone/rootfs <--wrong gid
drwxr-xr-x 1 100000 100000 162 May 27  2015 p1/rootfs
(The contents of p1_clone/rootfs/ has the correct gid).

Bug (2): cloning with the '-B overlayfs' option fails:
$lxc-clone -s -B overlayfs -o p1 -n p1_overlay
The error message is 'clone failed'.  strace output contains,
write(2, "clone failed\n", 13)    = 13

The host is ubuntu-14.04 with the stock 3.13 kernel and the lxc-daily ppa.