diff --git a/libext2/ext2_init.c b/libext2/ext2_init.c
index 2f29cb8..35703fe 100644
--- a/libext2/ext2_init.c
+++ b/libext2/ext2_init.c
@@ -5,9 +5,23 @@
  */
 
 #include "libext2.h"
+#include "ext2.h"
+#include "ext2_utils.h"
+
+static int is_ext2(device_io_t *device)
+{
+	struct ext2_super_block super;
+	ext2_get_super(device, &super);
+	if (super.s_magic == EXT2_SUPER_MAGIC)
+		return 1;
+	return 0;
+}
 
 int ext2_init(device_io_t *device, filesystem_io_t *fs)
 {
+	if (!is_ext2(device))
+		return -1;
+
 	fs->mount = ext2_mount;
 	fs->open = ext2_open;
 	fs->read = ext2_read;