code: func (ctrl *PersistentVolumeController) deleteVolume(volume *v1.PersistentVolume) {
  	_ = ctrl.volumes.store.Delete(volume)
  	klog.V(4).Infof("volume %q deleted", volume.Name)
  
  	if volume.Spec.ClaimRef == nil {
  		return
  	}
  	// sync the claim when its volume is deleted. Explicitly syncing the
  	// claim here in response to volume deletion prevents the claim from
  	// waiting until the next sync period for its Lost status.
  	claimKey := claimrefToClaimKey(volume.Spec.ClaimRef)
  	klog.V(5).Infof("deleteVolume[%s]: scheduling sync of claim %q", volume.Name, claimKey)
  	ctrl.claimQueue.Add(claimKey)
  }
docs: // deleteVolume runs in worker thread and handles "volume deleted" event.