[lxc-devel] lxc-clone do not work when overlayfs.v22 or higher is used

[KATOH Yasufumi]

Hi,

Now, lxc-clone with overlayfs (lxc-clone -s -B overlayfs) runs internally:
  mount -t overlayfs -oupperdir=${upper},lowerdir=${lower} lower dest

But, overlayfs.v22(kernel 3.15) or higher need the option "workdir=",
so lxc-clone do not work.

On 3.17 with overlayfs.v24, without workdir option:
  # mount -n -t overlayfs -o lowerdir=1,upperdir=2 overlayfs 3
  mount: wrong fs type, bad option, bad superblock on overlayfs,
         missing codepage or helper program, or other error

         In some cases useful info is found in syslog - try
         dmesg | tail or so.
  # dmesg | tail
  [  683.456473] overlayfs: missing upperdir or lowerdir or workdir

On 3.17 with overlayfs.v24, with workdir option:
  # mount -n -t overlayfs -o lowerdir=1,upperdir=2,workdir=3 overlayfs 4
  # cat /proc/mounts | grep overlayfs
  overlayfs /root/overlayfs/4 overlayfs rw,relatime,lowerdir=1,upperdir=2,workdir=3 0 0

See
  https://git.kernel.org/cgit/linux/kernel/git/mszeredi/vfs.git/tree/Documentation/filesystems/overlayfs.txt?h=overlayfs.v24

-- 
KATOH Yasufumi