1 files changed, 16 insertions, 3 deletions

diff --git a/arch/alpha/include/asm/fcntl.h b/arch/alpha/include/asm/fcntl.h
index 25da0017ec87..21b1117a0c61 100644
--- a/arch/alpha/include/asm/fcntl.h
+++ b/arch/alpha/include/asm/fcntl.h
@@ -1,8 +1,6 @@
 #ifndef _ALPHA_FCNTL_H
 #define _ALPHA_FCNTL_H
 
-/* open/fcntl - O_SYNC is only implemented on blocks devices and on files
-   located on an ext2 file system */
 #define O_CREAT          01000  /* not fcntl */
 #define O_TRUNC          02000  /* not fcntl */
 #define O_EXCL           04000  /* not fcntl */
@@ -10,13 +8,28 @@
 
 #define O_NONBLOCK       00004
 #define O_APPEND         00010
-#define O_SYNC          040000
+#define O_DSYNC         040000  /* used to be O_SYNC, see below */
 #define O_DIRECTORY     0100000 /* must be a directory */
 #define O_NOFOLLOW      0200000 /* don't follow links */
 #define O_LARGEFILE     0400000 /* will be set by the kernel on every open */
 #define O_DIRECT        02000000 /* direct disk access - should check with OSF/1 */
 #define O_NOATIME       04000000
 #define O_CLOEXEC       010000000 /* set close_on_exec */
+/*
+ * Before Linux 2.6.32 only O_DSYNC semantics were implemented, but using
+ * the O_SYNC flag.  We continue to use the existing numerical value
+ * for O_DSYNC semantics now, but using the correct symbolic name for it.
+ * This new value is used to request true Posix O_SYNC semantics.  It is
+ * defined in this strange way to make sure applications compiled against
+ * new headers get at least O_DSYNC semantics on older kernels.
+ *
+ * This has the nice side-effect that we can simply test for O_DSYNC
+ * wherever we do not care if O_DSYNC or O_SYNC is used.
+ *
+ * Note: __O_SYNC must never be used directly.
+ */
+#define __O_SYNC        020000000
+#define O_SYNC          (__O_SYNC|O_DSYNC)
 
 #define F_GETLK         7
 #define F_SETLK         8