Mapping and unmapping of a device in a publish path to its global map path and its
pod device map path are done by operation_executor through MapBlockVolume/UnmapBlockVolume
(MapBlockVolume and UnmapBlockVolume take care for lock, symlink, and bind mount).

Summary of block volume related CSI driver's methods are as follows:
 - GetGlobalMapPath returns a global map path,

			globalMapPath, string(podUID), mapErr)
	}

	return nil
}

// UnmapBlockVolume is a utility function to provide a common way of unmapping
// block device path for a specified volume and pod.  This function should be
// called by volume plugins that implements volume.BlockVolumeMapper.Map() method.
func UnmapBlockVolume(
	blkUtil volumepathhandler.BlockVolumePathHandler,
	globalUnmapPath,
	podDeviceUnmapPath,

		}

		// Execute common unmap
		unmapErr := util.UnmapBlockVolume(og.blkUtil, globalUnmapPath, podDeviceUnmapPath, volName, volumeToUnmount.PodUID)
		if unmapErr != nil {
			// On failure, return error. Caller will log and retry.
			eventErr, detailedErr := volumeToUnmount.GenerateError("UnmapVolume.UnmapBlockVolume failed", unmapErr)
			return volumetypes.NewOperationContext(eventErr, detailedErr, migrated)