diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/fcntl.h | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/include/asm-generic/fcntl.h b/include/asm-generic/fcntl.h index 495dc8af404..681ddf3e844 100644 --- a/include/asm-generic/fcntl.h +++ b/include/asm-generic/fcntl.h @@ -3,8 +3,6 @@ #include <linux/types.h> -/* open/fcntl - O_SYNC is only implemented on blocks devices and on files - located on an ext2 file system */ #define O_ACCMODE 00000003 #define O_RDONLY 00000000 #define O_WRONLY 00000001 @@ -27,8 +25,8 @@ #ifndef O_NONBLOCK #define O_NONBLOCK 00004000 #endif -#ifndef O_SYNC -#define O_SYNC 00010000 +#ifndef O_DSYNC +#define O_DSYNC 00010000 /* used to be O_SYNC, see below */ #endif #ifndef FASYNC #define FASYNC 00020000 /* fcntl, for BSD compatibility */ @@ -51,6 +49,25 @@ #ifndef O_CLOEXEC #define O_CLOEXEC 02000000 /* set close_on_exec */ #endif + +/* + * 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. + */ +#ifndef O_SYNC +#define __O_SYNC 04000000 +#define O_SYNC (__O_SYNC|O_DSYNC) +#endif + #ifndef O_NDELAY #define O_NDELAY O_NONBLOCK #endif |