Fix S3 delete for non-empty directory markers (#8740)

* Fix S3 delete for non-empty directory markers

* Address review feedback on directory marker deletes

* Stabilize FUSE concurrent directory operations

test/fuse_integration/framework_test.go

@@ -97,11 +97,26 @@ func NewFuseTestFramework(t *testing.T, config *TestConfig) *FuseTestFramework {
 // freePort asks the OS for a free TCP port.
 func freePort(t *testing.T) int {
 	t.Helper()
-	l, err := net.Listen("tcp", "127.0.0.1:0")
-	require.NoError(t, err)
-	port := l.Addr().(*net.TCPAddr).Port
-	l.Close()
-	return port
+	const (
+		minServicePort = 20000
+		maxServicePort = 55535 // SeaweedFS gRPC service uses httpPort + 10000.
+	)
+
+	portCount := maxServicePort - minServicePort + 1
+	start := minServicePort + int(time.Now().UnixNano()%int64(portCount))
+
+	for attempt := 0; attempt < 512; attempt++ {
+		port := minServicePort + (start-minServicePort+attempt)%portCount
+		l, err := net.Listen("tcp", net.JoinHostPort("127.0.0.1", strconv.Itoa(port)))
+		if err != nil {
+			continue
+		}
+		l.Close()
+		return port
+	}
+
+	t.Fatalf("failed to allocate port <= %d after repeated attempts", maxServicePort)
+	return 0
 }
 
 // Setup starts SeaweedFS cluster and mounts FUSE filesystem

test/s3/normal/s3_integration_test.go

@@ -99,6 +99,10 @@ func TestS3Integration(t *testing.T) {
 		testDeleteObject(t, cluster)
 	})
 
+	t.Run("DeleteDirectoryMarkerWithChildren", func(t *testing.T) {
+		testDeleteDirectoryMarkerWithChildren(t, cluster)
+	})
+
 	t.Run("DeleteBucket", func(t *testing.T) {
 		testDeleteBucket(t, cluster)
 	})
@@ -754,6 +758,47 @@ func testDeleteObject(t *testing.T, cluster *TestCluster) {
 	t.Logf("✓ Deleted object: %s/%s", bucketName, objectKey)
 }
 
+func testDeleteDirectoryMarkerWithChildren(t *testing.T, cluster *TestCluster) {
+	bucketName := createTestBucket(t, cluster, "test-delete-dir-marker-")
+	childKey := "test-content/file1.txt"
+	directoryMarkerKey := "test-content/"
+
+	_, err := cluster.s3Client.PutObject(&s3.PutObjectInput{
+		Bucket: aws.String(bucketName),
+		Key:    aws.String(childKey),
+		Body:   bytes.NewReader([]byte("child")),
+	})
+	require.NoError(t, err)
+
+	_, err = cluster.s3Client.PutObject(&s3.PutObjectInput{
+		Bucket:      aws.String(bucketName),
+		Key:         aws.String(directoryMarkerKey),
+		Body:        bytes.NewReader(nil),
+		ContentType: aws.String("application/octet-stream"),
+	})
+	require.NoError(t, err)
+
+	_, err = cluster.s3Client.DeleteObject(&s3.DeleteObjectInput{
+		Bucket: aws.String(bucketName),
+		Key:    aws.String(directoryMarkerKey),
+	})
+	require.NoError(t, err, "Deleting a directory marker should succeed even when children exist")
+
+	listResp, err := cluster.s3Client.ListObjectsV2(&s3.ListObjectsV2Input{
+		Bucket: aws.String(bucketName),
+		Prefix: aws.String("test-content/"),
+	})
+	require.NoError(t, err)
+
+	foundKeys := make(map[string]bool)
+	for _, obj := range listResp.Contents {
+		foundKeys[aws.StringValue(obj.Key)] = true
+	}
+
+	assert.True(t, foundKeys[childKey], "Child object should remain after deleting the directory marker")
+	assert.False(t, foundKeys[directoryMarkerKey], "Directory marker should no longer be listed after deletion")
+}
+
 func testDeleteBucket(t *testing.T, cluster *TestCluster) {
 	bucketName := "test-delete-bucket-" + randomString(8)