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