diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
new file mode 100644
index 0000000..b9176ee
--- /dev/null
+++ b/fs/ext4/bitmap.c
@@ -0,0 +1,32 @@
+/*
+ *  linux/fs/ext3/bitmap.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+
+#ifdef EXT3FS_DEBUG
+
+static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
+
+unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
+{
+	unsigned int i;
+	unsigned long sum = 0;
+
+	if (!map)
+		return (0);
+	for (i = 0; i < numchars; i++)
+		sum += nibblemap[map->b_data[i] & 0xf] +
+			nibblemap[(map->b_data[i] >> 4) & 0xf];
+	return (sum);
+}
+
+#endif  /*  EXT3FS_DEBUG  */
+