This implements the new Put() operation such that
Get()/Put() maintains a refcount for each ID, mounting
only on first Get() and unmounting on the last Get().
This means we avoid littering the system with lots of mounts
and active devicemapper devices and free resources related
to them.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
asdfljk
Upstream-commit: 886f650d9b2133fb61e7cc5b0bb7795246852026
Component: engine
4d1276ba85