diff --git a/minato/filesystems/osfs.py b/minato/filesystems/osfs.py
index 2af7040..45b6e14 100644
--- a/minato/filesystems/osfs.py
+++ b/minato/filesystems/osfs.py
@@ -28,7 +28,7 @@ def delete(self) -> None:
         remove_file_or_directory(self._path)
 
     def get_version(self) -> str | None:
-        return None
+        return str(self._path.stat().st_mtime_ns)
 
     @overload
     def open_file(
diff --git a/minato/minato.py b/minato/minato.py
index 8d647c3..42d5221 100644
--- a/minato/minato.py
+++ b/minato/minato.py
@@ -161,7 +161,7 @@ def cached_path(
 
         if is_local(url_or_filename):
             url_or_filename = extract_path(url_or_filename)
-            if not extract and not is_archive_file(url_or_filename):
+            if not (extract and is_archive_file(url_or_filename)):
                 local_path = Path(url_or_filename)
                 if not local_path.exists():
                     raise FileNotFoundError(local_path)