Do not resize file system on a read-only mount

pkg/volume/util/operationexecutor/operation_generator.go

@@ -544,6 +544,7 @@ func (og *operationGenerator) resizeFileSystem(volumeToMount VolumeToMount, devi
 		glog.V(6).Infof("Resizing is not enabled for this volume %s", volumeToMount.VolumeName)
 		return nil
 	}
+
 	mounter := og.volumePluginMgr.Host.GetMounter(pluginName)
 	// Get expander, if possible
 	expandableVolumePlugin, _ :=
@@ -565,6 +566,13 @@ func (og *operationGenerator) resizeFileSystem(volumeToMount VolumeToMount, devi
 			// File system resize was requested, proceed
 			glog.V(4).Infof(volumeToMount.GenerateMsgDetailed("MountVolume.resizeFileSystem entering", fmt.Sprintf("DevicePath %q", volumeToMount.DevicePath)))
 
+			if volumeToMount.VolumeSpec.ReadOnly {
+				simpleMsg, detailedMsg := volumeToMount.GenerateMsg("MountVolume.resizeFileSystem failed", "requested read-only file system")
+				glog.Warningf(detailedMsg)
+				og.recorder.Eventf(volumeToMount.Pod, v1.EventTypeWarning, kevents.FileSystemResizeFailed, simpleMsg)
+				return nil
+			}
+
 			diskFormatter := &mount.SafeFormatAndMount{
 				Interface: mounter,
 				Exec:      og.volumePluginMgr.Host.GetExec(expandableVolumePlugin.GetPluginName()),