DOSFS_ToDosFCBFormat: fail if extension longer than 3 characters.

files/dos_fs.c

diff --git a/files/dos_fs.c b/files/dos_fs.c
index 4ba1c23..a77b2b9 100644
--- a/files/dos_fs.c
+++ b/files/dos_fs.c
@@ -240,7 +240,12 @@
         }
     }
     buffer[11] = '\0';
-    return TRUE;
+
+    /* at most 3 character of the extension are processed
+     * is something behind this ? 
+     */
+    if (*p == '*') p++; /* skip wildcard */
+    return IS_END_OF_NAME(*p);
 }