Don't report deletion of attached volume as warning

It is part of normal cluster operation. When a pod and PVC are deleted at
the same time (e.g. because of the whole namespace was deleted), PV
controller may try to delete a volume that is still detached.

"Warning" is too strong here, it is going to heal relatively quickly.

Author: jsafrane

staging/src/k8s.io/cloud-provider/volume/errors/errors.go

@@ -65,3 +65,13 @@ func NewDanglingError(msg string, node k8stypes.NodeName, devicePath string) err
 		DevicePath:  devicePath,
 	}
 }
+
+// IsDanglingError returns true if an error is DanglingAttachError
+func IsDanglingError(err error) bool {
+	switch err.(type) {
+	case *DanglingAttachError:
+		return true
+	default:
+		return false
+	}
+}

staging/src/k8s.io/legacy-cloud-providers/aws/aws.go

@@ -2578,6 +2578,10 @@ func (c *Cloud) DeleteDisk(volumeName KubernetesVolumeID) (bool, error) {
 			klog.V(2).Infof("Volume %s not found when deleting it, assuming it's deleted", awsDisk.awsID)
 			return false, nil
 		}
+		if volerr.IsDanglingError(err) {
+			// The volume is still attached somewhere
+			return false, volerr.NewDeletedVolumeInUseError(err.Error())
+		}
 		klog.Error(err)
 	}
 
@@ -2598,7 +2602,7 @@ func (c *Cloud) checkIfAvailable(disk *awsDisk, opName string, instance string)
 	}
 
 	volumeState := aws.StringValue(info.State)
-	opError := fmt.Sprintf("Error %s EBS volume %q", opName, disk.awsID)
+	opError := fmt.Sprintf("error %s EBS volume %q", opName, disk.awsID)
 	if len(instance) != 0 {
 		opError = fmt.Sprintf("%q to instance %q", opError, instance)
 	}