diff --git a/filesize.go b/filesize.go
new file mode 100644
index 0000000..350b753
--- /dev/null
+++ b/filesize.go
@@ -0,0 +1,25 @@
+package raft
+
+import (
+	"io/fs"
+)
+
+// fileSize returns the file-size of an fs.File.
+func fileSize(file fs.File) (int64, error) {
+
+	if nil == file {
+		return 0, errNilFile
+	}
+
+	var fileinfo fs.FileInfo
+	{
+		var err error
+
+		fileinfo, err = fileInfo(file)
+		if nil != err {
+			return 0, err
+		}
+	}
+
+	return fileinfo.Size(), nil
+}