1 files changed, 3 insertions, 1 deletions
diff --git a/file.c b/file.c
index 0310f235ca..2659ef7f6a 100644
--- a/file.c
+++ b/file.c
@@ -138,8 +138,10 @@ file_path_convert(VALUE name)
     if (rb_default_internal_encoding() != NULL
 	    && rb_usascii_encoding() != fname_encoding
 	    && rb_ascii8bit_encoding() != fname_encoding
-	    && (fs_encoding = rb_filesystem_encoding()) != fname_encoding) {
+	    && (fs_encoding = rb_filesystem_encoding()) != fname_encoding
+	    && !rb_enc_str_asciionly_p(name)) {
 	/* Don't call rb_filesystem_encoding() before US-ASCII and ASCII-8BIT */
+	/* fs_encoding should be ascii compatible */
 	name = rb_str_conv_enc(name, fname_encoding, fs_encoding);
     }
 #endif