There have been some cases where umount, a device can be busy for a very
short duration. Maybe its udev rules, or maybe it is runc related races
or probably it is something else. We don't know yet.
If deferred removal is enabled but deferred deletion is not, then for the
case of "docker run -ti --rm fedora bash", a container will exit, device
will be deferred removed and then immediately a call will come to delete
the device. It is possible that deletion will fail if device was busy
at that time.
A device can't be deleted if it can't be removed/deactivated first. There
is only one exception and that is when deferred deletion is on. In that
case graph driver will keep track of deleted device and try to delete it
later and return success to caller.
Always make sure that device deactivation is synchronous when device is
being deleted (except the case when deferred deletion is enabled).
This should also take care of small races when device is busy for a short
duration and it is being deleted.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Upstream-commit: 36cb6efebc599900b691e206fb9e99d3aa2fb9a3
Component: engine
56378645d0