mv HasMountRefs from mount pkg to vol/util

HasMountRefs is only used internal to K8s and should not be moved out
with the mount package. move it to pkg/volume/util instead.

pkg/volume/util/util.go

@@ -576,3 +576,20 @@ func addContainerVolumes(containers []v1.Container, mounts, devices sets.String)
 		}
 	}
 }
+
+// HasMountRefs checks if the given mountPath has mountRefs.
+// TODO: this is a workaround for the unmount device issue caused by gci mounter.
+// In GCI cluster, if gci mounter is used for mounting, the container started by mounter
+// script will cause additional mounts created in the container. Since these mounts are
+// irrelevant to the original mounts, they should be not considered when checking the
+// mount references. Current solution is to filter out those mount paths that contain
+// the string of original mount path.
+// Plan to work on better approach to solve this issue.
+func HasMountRefs(mountPath string, mountRefs []string) bool {
+	for _, ref := range mountRefs {
+		if !strings.Contains(ref, mountPath) {
+			return true
+		}
+	}
+	return false
+}