fusefs: run the io tests with direct io, too

Now the io tests are run in all cache modes.  The fusefs test suite can now
get adequate coverage without changing the value of
vfs.fusefs.data_cache_mode, which is only needed for legacy file systems
now.

Sponsored by:	The FreeBSD Foundation

tests/sys/fs/fusefs/io.cc

@@ -51,6 +51,28 @@ extern "C" {
 
 using namespace testing;
 
+enum cache_mode {
+	Uncached,
+	Writethrough,
+	Writeback,
+	WritebackAsync
+};
+
+const char *cache_mode_to_s(enum cache_mode cm) {
+	switch (cm) {
+	case Uncached:
+		return "Uncached";
+	case Writethrough:
+		return "Writethrough";
+	case Writeback:
+		return "Writeback";
+	case WritebackAsync:
+		return "WritebackAsync";
+	default:
+		return "Unknown";
+	}
+}
+
 const char FULLPATH[] = "mountpoint/some_file.txt";
 const char RELPATH[] = "some_file.txt";
 const uint64_t ino = 42;
@@ -76,13 +98,15 @@ static void compare(const void *tbuf, const void *controlbuf, off_t baseofs,
 	}
 }
 
-class Io: public FuseTest,
+typedef tuple<bool, uint32_t, cache_mode> IoParam;
-	  public WithParamInterface<tuple<bool, uint32_t, bool, bool>> {
+
+class Io: public FuseTest, public WithParamInterface<IoParam> {
 public:
 int m_backing_fd, m_control_fd, m_test_fd;
 off_t m_filesize;
+bool m_direct_io;
 
-Io(): m_backing_fd(-1), m_control_fd(-1) {};
+Io(): m_backing_fd(-1), m_control_fd(-1), m_direct_io(false) {};
 
 void SetUp()
 {
@@ -98,16 +122,35 @@ void SetUp()
 	if (get<0>(GetParam()))
 		m_init_flags |= FUSE_ASYNC_READ;
 	m_maxwrite = get<1>(GetParam());
-	if (get<2>(GetParam()))
+	switch (get<2>(GetParam())) {
-		m_init_flags |= FUSE_WRITEBACK_CACHE;
+		case Uncached:
-	m_async = get<3>(GetParam());
+			m_direct_io = true;
+			break;
+		case WritebackAsync:
+			m_async = true;
+			/* FALLTHROUGH */
+		case Writeback:
+			m_init_flags |= FUSE_WRITEBACK_CACHE;
+			/* FALLTHROUGH */
+		case Writethrough:
+			break;
+		default:
+			FAIL() << "Unknown cache mode";
+	}
 
 	FuseTest::SetUp();
 	if (IsSkipped())
 		return;
 
+	if (verbosity > 0) {
+		printf("Test Parameters: init_flags=%#x maxwrite=%#x "
+		    "%sasync cache=%s\n",
+		    m_init_flags, m_maxwrite, m_async? "" : "no",
+		    cache_mode_to_s(get<2>(GetParam())));
+	}
+
 	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
-	expect_open(ino, 0, 1);
+	expect_open(ino, m_direct_io ? FOPEN_DIRECT_IO : 0, 1);
 	EXPECT_CALL(*m_mock, process(
 		ResultOf([=](auto in) {
 			return (in.header.opcode == FUSE_WRITE &&
@@ -488,11 +531,13 @@ TEST_P(Io, resize_a_valid_buffer_while_extending)
 INSTANTIATE_TEST_CASE_P(Io, Io,
 	Combine(Bool(),					/* async read */
 		Values(0x1000, 0x10000, 0x20000),	/* m_maxwrite */
-		Bool(),					/* writeback cache */
+		Values(Uncached, Writethrough, Writeback, WritebackAsync)
-		Bool()));				/* m_async */
+	)
+);
 
 INSTANTIATE_TEST_CASE_P(Io, IoCacheable,
 	Combine(Bool(),					/* async read */
 		Values(0x1000, 0x10000, 0x20000),	/* m_maxwrite */
-		Bool(),					/* writeback cache */
+		Values(Writethrough, Writeback, WritebackAsync)
-		Bool()));				/* m_async */
+	)
+);