1 files changed, 44 insertions, 0 deletions
diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c
index ce6d661..0ac49ce 100644
--- a/tests/qtest/migration-helpers.c
+++ b/tests/qtest/migration-helpers.c
@@ -18,6 +18,7 @@
 #include "qapi/error.h"
 #include "qapi/qmp/qlist.h"
 #include "qemu/cutils.h"
+#include "qemu/memalign.h"
 
 #include "migration-helpers.h"
 
@@ -473,3 +474,46 @@ 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_TRUNC | O_DIRECT;
+    void *buf;
+    ssize_t ret, len;
+    uint64_t offset;
+
+    fd = open(filename, flags, 0660);
+    if (fd < 0) {
+        unlink(filename);
+        return false;
+    }
+
+    /*
+     * Using 1MB alignment as conservative choice to satisfy any
+     * plausible architecture default page size, and/or filesystem
+     * alignment restrictions.
+     */
+    len = 0x100000;
+    offset = 0x100000;
+
+    buf = qemu_try_memalign(len, len);
+    g_assert(buf);
+
+    ret = pwrite(fd, buf, len, offset);
+    unlink(filename);
+    g_free(buf);
+
+    if (ret < 0) {
+        return false;
+    }
+
+    return true;
+}
+#endif