diff --git a/fs/fs_fcntl.c b/fs/fs_fcntl.c
index ff53b0f205a..b4d09570568 100644
--- a/fs/fs_fcntl.c
+++ b/fs/fs_fcntl.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_fcntl.c
  *
- *   Copyright (C) 2009, 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -49,6 +49,13 @@
 
 #include "fs_internal.h"
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define ACCESS_MODES   (O_RDONLY | O_WRONLY | O_RDWR)
+#define CREATION_MODES (O_CREAT | O_EXCL | O_APPEND | O_TRUNC)
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -143,7 +150,11 @@ static inline int file_vfcntl(int fildes, int cmd, va_list ap)
          */
 
         {
-          this_file->f_oflags = va_arg(ap, int);
+          int oflags = va_arg(ap, int);
+
+          oflags              &= ~(ACCESS_MODES | CREATION_MODES);
+          this_file->f_oflags &=  (ACCESS_MODES | CREATION_MODES);
+          this_file->f_oflags |=  oflags;
         }
         break;
 
diff --git a/include/fcntl.h b/include/fcntl.h
index 382c5be16b9..0d423a5d064 100644
--- a/include/fcntl.h
+++ b/include/fcntl.h
@@ -79,6 +79,13 @@
 
 #define _O_MAXBIT   8
 
+/* Synonyms historically used as F_SETFL flags (BSD).  Also FASYNC. */
+
+#define FNDELAY     O_NONBLOCK
+#define FNONBLOCK   O_NONBLOCK
+#define FAPPEND     O_APPEND
+#define FSYNC       O_SYNC
+
 /* fcntl() commands */
 
 #define F_DUPFD     0  /* Duplicate a file descriptor */