getNestedMountpoints may not group mountpoints correctly

[claudiubelu]

What happened?

getNestedMountpoints [1] relies on sort.Strings to have all the mount points sorted and grouped. For example, the following strings are sorted in this exact order:

/dir/nested, /dir/nested-vol, /dir/nested.vol, /dir/nested/double, /dir/nested2

With the current implementation, getNestedMountpoints, an incorrect set of nested directories would be returned. For example, if we add the nested-vol and nested.vol volume mounts into the TestGetNestedMountpoints/Unsorted Nested Pod test, we would get:

=== RUN   TestGetNestedMountpoints
    nested_volumes_test.go:232: Unsorted Nested Pod: unexpected nested directories created:
        expected: map[nested:{} nested-vol:{} nested.vol:{} nested2:{}]
             got: map[nested:{} nested-vol:{} nested.vol:{} nested/double:{} nested2:{}]
--- FAIL: TestGetNestedMountpoints (0.00s)

This is worse on Windows, where paths usually have backslashes instead (with no test changes):

=== RUN   TestGetNestedMountpoints
    nested_volumes_test.go:230: Unsorted Nested Pod: unexpected nested directories created:
        expected: map[nested:{} nested2:{}]
             got: map[nested:{} nested2:{} nested\double:{}]
--- FAIL: TestGetNestedMountpoints (0.02s)

[1]

kubernetes/pkg/volume/util/nested_volumes.go

Line 33 in 64a38b1

func getNestedMountpoints(name, baseDir string, pod v1.Pod) ([]string, error) {

What did you expect to happen?

getNestedMountpoints should group mount points correctly.

How can we reproduce it (as minimally and precisely as possible)?

git diff pkg/
diff --git a/pkg/volume/util/nested_volumes_test.go b/pkg/volume/util/nested_volumes_test.go
index f4f4add..e73730c 100644
--- a/pkg/volume/util/nested_volumes_test.go
+++ b/pkg/volume/util/nested_volumes_test.go
@@ -89,7 +89,7 @@ func TestGetNestedMountpoints(t *testing.T) {
                {
                        name:     "Unsorted Nested Pod",
                        err:      false,
-                       expected: sets.NewString("nested", "nested2"),
+                       expected: sets.NewString("nested", "nested2", "nested-vol", "nested.vol"),
                        volname:  "vol1",
                        pod: v1.Pod{
                                ObjectMeta: metav1.ObjectMeta{
@@ -106,6 +106,8 @@ func TestGetNestedMountpoints(t *testing.T) {
                                                                {MountPath: "/ignore2", Name: "vol5"},
                                                                {MountPath: "/dir", Name: "vol1"},
                                                                {MountPath: "/dir/nested2", Name: "vol3"},
+                                                               {MountPath: "/dir/nested-vol", Name: "vol6"},
+                                                               {MountPath: "/dir/nested.vol", Name: "vol7"},
                                                        },
                                                },
                                        },

Anything else we need to know?

/kind bug

/sig windows

Kubernetes version

Kubernetes master, Kubernetes v1.25 and older.

Cloud provider

N/A

OS version

N/A

Install tools

Container runtime (CRI) and version (if applicable)

Related plugins (CNI, CSI, ...) and versions (if applicable)

[marosset]

/triage accepted
/milestone v1.26