storage: use volatile containers
storage: use volatile containers

overlay supports a new mount option "volatile" that reduces I/O by
ignoring fsync and syncfs requests.

Enable it for CRI-O containers as they are "volatile" by nature and
are not supposed to survive a reboot.

Even in the case containers created by CRI-O are persistent, we
already have code in place to throw away the storage if the shutdown
was not clean, so they will be cleaned up in any case.

Signed-off-by: Giuseppe Scrivano <20002b7b24c75512093a71a58285826d5c504fca@redhat.com>

nalind/cri-o,kubernetes-incubator/ocid,nalind/cri-o,kubernetes-incubator/ocid,kubernetes-incubator/ocid,nalind/cri-o