This makes sure that multiple users of MountPoint pointer can
mount/unmount without affecting each other.
Before this PR, if you run a container (stay running), then do `docker
cp`, when the `docker cp` is done the MountPoint is mutated such that
when the container stops the volume driver will not get an Unmount
request. Effectively there would be two mounts with only one unmount.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: df0d317a64e4a74433359e826bc1d606e050a5ed
Component: engine
Brian Goff
ce01ee60c2