ovl: support idmapped layers

Now that overlay is able to take a layers idmapping into account allow
overlay mounts to be created on top of idmapped mounts. Since NFS
doesn't support idmapped mounts we don't allow idmapped base layers in
combination with the nfs_export=on mount option.

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
1 file changed