diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index df315dcdd35d153dee83b8f2cf5dc202cbd59213..1856d5ecd80954bfae9db50de91130fbba02ce10 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -91,7 +91,14 @@ static int is_multimedia_file(const unsigned char *s, const char *sub)
 	size_t slen = strlen(s);
 	size_t sublen = strlen(sub);
 
-	if (sublen > slen)
+	/*
+	 * filename format of multimedia file should be defined as:
+	 * "filename + '.' + extension".
+	 */
+	if (slen < sublen + 2)
+		return 0;
+
+	if (s[slen - sublen - 1] != '.')
 		return 0;
 
 	return !strncasecmp(s + slen - sublen, sub, sublen);