Merge pull request #67745 from feiskyer/choose-zones

Automatic merge from submit-queue (batch tested with PRs 67745, 67432, 67569, 67825, 67943). If you want to cherry-pick this change to another branch, please follow the instructions here: https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md.

Fix panic when choosing zone or zones for volume

**What this PR does / why we need it**:

Fix panic when choosing zone or zones for volume, so that zoneSlice won't divide by zero now.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

cc @ddebroy @andyzhangx

pkg/volume/util/util_test.go

@@ -647,6 +647,17 @@ func TestChooseZoneForVolume(t *testing.T) {
 			VolumeName: "medium-henley--4",
 			Expected:   "c", // hash("") + 4 == 2 mod 3
 		},
+		// Test for no zones
+		{
+			Zones:      sets.NewString(),
+			VolumeName: "medium-henley--1",
+			Expected:   "",
+		},
+		{
+			Zones:      nil,
+			VolumeName: "medium-henley--2",
+			Expected:   "",
+		},
 	}
 
 	for _, test := range tests {
@@ -992,6 +1003,17 @@ func TestChooseZonesForVolume(t *testing.T) {
 			NumZones:   3,
 			Expected:   sets.NewString("a" /* hash("henley") == 0 + 3 + 6(startingIndex) */, "b", "c"),
 		},
+		// Test for no zones
+		{
+			Zones:      sets.NewString(),
+			VolumeName: "henley-1",
+			Expected:   sets.NewString(),
+		},
+		{
+			Zones:      nil,
+			VolumeName: "henley-2",
+			Expected:   sets.NewString(),
+		},
 	}
 
 	for _, test := range tests {