[PATCH v4 29/34] tests/qtest/migration: Add tests for file migration with direct-io

[Fabiano Rosas <farosas@suse.de>]

The tests are only allowed to run in systems that know and in
filesystems which support O_DIRECT.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 tests/qtest/migration-helpers.c | 39 ++++++++++++++++++++++++++++++
 tests/qtest/migration-helpers.h |  1 +
 tests/qtest/migration-test.c    | 42 +++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c
index e451dbdbed..4ae43db1ca 100644
--- a/tests/qtest/migration-helpers.c
+++ b/tests/qtest/migration-helpers.c
@@ -323,3 +323,42 @@ void migration_test_add(const char *path, void (*fn)(void))
     qtest_add_data_func_full(path, test, migration_test_wrapper,
                              migration_test_destroy);
 }
+
+#ifdef O_DIRECT
+/*
+ * Probe for O_DIRECT support on the filesystem. Since this is used
+ * for tests, be conservative, if anything fails, assume it's
+ * unsupported.
+ */
+bool probe_o_direct_support(const char *tmpfs)
+{
+    g_autofree char *filename = g_strdup_printf("%s/probe-o-direct", tmpfs);
+    int fd, flags = O_CREAT | O_RDWR | O_DIRECT;
+    void *buf;
+    ssize_t ret, len;
+    uint64_t offset;
+
+    fd = open(filename, flags, 0660);
+    if (fd < 0) {
+        unlink(filename);
+        return false;
+    }
+
+    /*
+     * Assuming 4k should be enough to satisfy O_DIRECT alignment
+     * requirements. The migration code uses 1M to be conservative.
+     */
+    len = 0x100000;
+    offset = 0x100000;
+
+    buf = g_malloc0(len);
+    ret = pwrite(fd, buf, len, offset);
+    unlink(filename);
+
+    if (ret < 0) {
+        return false;
+    }
+
+    return true;
+}
+#endif
diff --git a/tests/qtest/migration-helpers.h b/tests/qtest/migration-helpers.h
index 3bf7ded1b9..d4d641899a 100644
--- a/tests/qtest/migration-helpers.h
+++ b/tests/qtest/migration-helpers.h
@@ -52,5 +52,6 @@ char *find_common_machine_version(const char *mtype, const char *var1,
                                   const char *var2);
 char *resolve_machine_version(const char *alias, const char *var1,
                               const char *var2);
+bool probe_o_direct_support(const char *tmpfs);
 void migration_test_add(const char *path, void (*fn)(void));
 #endif /* MIGRATION_HELPERS_H */
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index cb9f16f78e..0931ba18df 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -2287,6 +2287,43 @@ static void test_multifd_file_fixed_ram(void)
     test_file_common(&args, true);
 }
 
+#ifdef O_DIRECT
+static void *migrate_fixed_ram_dio_start(QTestState *from,
+                                                 QTestState *to)
+{
+    migrate_fixed_ram_start(from, to);
+    migrate_set_parameter_bool(from, "direct-io", true);
+    migrate_set_parameter_bool(to, "direct-io", true);
+
+    return NULL;
+}
+
+static void *migrate_multifd_fixed_ram_dio_start(QTestState *from,
+                                                 QTestState *to)
+{
+    migrate_multifd_fixed_ram_start(from, to);
+    return migrate_fixed_ram_dio_start(from, to);
+}
+
+static void test_multifd_file_fixed_ram_dio(void)
+{
+    g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
+                                           FILE_TEST_FILENAME);
+    MigrateCommon args = {
+        .connect_uri = uri,
+        .listen_uri = "defer",
+        .start_hook = migrate_multifd_fixed_ram_dio_start,
+    };
+
+    if (!probe_o_direct_support(tmpfs)) {
+        g_test_skip("Filesystem does not support O_DIRECT");
+        return;
+    }
+
+    test_file_common(&args, true);
+}
+
+#endif /* O_DIRECT */
 
 static void test_precopy_tcp_plain(void)
 {
@@ -3634,6 +3671,11 @@ int main(int argc, char **argv)
                        test_multifd_fd_fixed_ram);
 #endif
 
+#ifdef O_DIRECT
+    migration_test_add("/migration/multifd/file/fixed-ram/dio",
+                       test_multifd_file_fixed_ram_dio);
+#endif
+
 #ifdef CONFIG_GNUTLS
     migration_test_add("/migration/precopy/unix/tls/psk",
                        test_precopy_unix_tls_psk);
-- 
2.35.3