diff -Naurp postfix-2.9.1/src/postmap/postmap.c postfix-2.9.1.dlucio/src/postmap/postmap.c
--- postfix-2.9.1/src/postmap/postmap.c	2012-03-16 15:37:48.551885684 -0400
+++ postfix-2.9.1.dlucio/src/postmap/postmap.c	2012-03-16 15:43:58.732126366 -0400
@@ -766,8 +766,8 @@ static int postmap_upgrade(const char *m
 
 static NORETURN usage(char *myname)
 {
-    msg_fatal("usage: %s [-Nfinoprsvw] [-c config_dir] [-d key] [-q key] [map_type:]file...",
-	      myname);
+     msg_fatal("usage: %s [-Nfhimnoprsuvw] [-c config_dir] [-d key] [-q key] [map_type:]file...",
+              myname);
 }
 
 MAIL_VERSION_STAMP_DECLARE;
diff -Naurp postfix-2.9.1/src/util/dict_dbm.c postfix-2.9.1.dlucio/src/util/dict_dbm.c
--- postfix-2.9.1/src/util/dict_dbm.c	2012-03-16 15:37:48.554885669 -0400
+++ postfix-2.9.1.dlucio/src/util/dict_dbm.c	2012-03-16 15:40:06.757228849 -0400
@@ -437,6 +437,10 @@ DICT   *dict_dbm_open(const char *path,
 	    msg_fatal("shared-lock database %s for open: %m", dbm_path);
     }
 
+#ifdef HAVE_GDBM
+    msg_fatal("%s: gdbm maps use locking that is incompatible with postfix.  Use a hash map instead.",
+		 path);
+#endif
     /*
      * XXX SunOS 5.x has no const in dbm_open() prototype.
      */