On Sep 10, 2009 22:25 +0200, Christoph Hellwig wrote: > +/* > + * 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. Doesn't it make sense that applications that actually know what they are doing may want to start using __O_SYNC directly at some point in the future? It makes sense to code the kernel to handle both of these flags appropriately (i.e. if __O_SYNC is set, but O_DSYNC is not then treat this as the proper "O_SYNC"). > Index: linux-2.6/arch/alpha/include/asm/fcntl.h > =================================================================== > --- linux-2.6.orig/arch/alpha/include/asm/fcntl.h 2009-09-10 16:31:47.720004025 -0300 > +++ linux-2.6/arch/alpha/include/asm/fcntl.h 2009-09-10 16:33:55.087294444 -0300 > #define O_CLOEXEC 010000000 /* set close_on_exec */ > +#define __O_SYNC 010000000 These two flags have the same value... Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
