A lot of time device mapper devices leak across mount namespace which docker
does not know about and when docker tries to deactivate/delete device,
operation fails as device is open in some mount namespace.
Create a mechanism where one can defer the device deactivation/deletion
so that docker operation does not fail and device automatically goes
away when last reference to it is dropped.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
DM_UDEV_DISABLE_LIBRARY_FALLBACK is disabled by most applications today
when using device-mapper, and ensuring that device-mapper is in sync
with udev. This flag instructs devicemapper to not fallback to creating
the device nodes itself. In the case of udev sync not being supported,
devicemapper will attempt to create the devices in a timely manner,
regardless of udev.
Signed-off-by: Vincent Batts <vbatts@redhat.com>
Otherwise udev can unecessarily execute various rules (and issue
scanning IO, etc) against the thin-pool -- which can never be a
top-level device.
Docker-DCO-1.1-Signed-off-by: Mike Snitzer <snitzer@redhat.com> (github: snitm)
