Fix issue with race condition during pod deletion

This PR fixes two issues
1. When desired_state_populator removes podvolume state, it should check
whether the actual state already has the volume before deleting it to
make sure actual state has a chance to add the volume into the state
2. When checking podVolume still exists, it not only checks the actual
state, but also the volume disk directory because actual state might not
reflect the real world when kubelet starts.

pkg/kubelet/kubelet_getters.go

@@ -274,6 +274,24 @@ func (kl *Kubelet) getPodVolumePathListFromDisk(podUID types.UID) ([]string, err
 	return volumes, nil
 }
 
+func (kl *Kubelet) getMountedVolumePathListFromDisk(podUID types.UID) ([]string, error) {
+	mountedVolumes := []string{}
+	volumePaths, err := kl.getPodVolumePathListFromDisk(podUID)
+	if err != nil {
+		return mountedVolumes, err
+	}
+	for _, volumePath := range volumePaths {
+		isNotMount, err := kl.mounter.IsLikelyNotMountPoint(volumePath)
+		if err != nil {
+			return mountedVolumes, err
+		}
+		if !isNotMount {
+			mountedVolumes = append(mountedVolumes, volumePath)
+		}
+	}
+	return mountedVolumes, nil
+}
+
 // GetVersionInfo returns information about the version of cAdvisor in use.
 func (kl *Kubelet) GetVersionInfo() (*cadvisorapiv1.VersionInfo, error) {
 	return kl.cadvisor.VersionInfo()