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Date: Fri, 28 Aug 2009 17:08:38 -0400
From: Christoph Hellwig <hch@infradead.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>, Jamie Lokier <jamie@shareable.org>,
       linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
       torvalds@linux-foundation.org
Subject: Re: adding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers
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References: <20090824023422.GA775@infradead.org> <20090827143459.GB31453@shareable.org> <20090827171044.GA5427@infradead.org> <4A96C14C.8040105@redhat.com> <20090828154647.GA15808@infradead.org> <4A98008B.6050503@redhat.com> <20090828161745.GA8755@infradead.org> <4A9806D9.5050409@redhat.com> <20090828164106.GA9951@infradead.org> <4A984337.7080009@redhat.com>
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On Fri, Aug 28, 2009 at 01:51:03PM -0700, Ulrich Drepper wrote:
> No, that's not a good idea.  This would mean a program compiled with  
> newer headers is using O_SYNC which isn't known to old kernels and  
> ignored.  Such programs will then not even get the current O_DSYNC 
> benefits.

Ok, let's agree on how to proceed:


once 2.6.31 is out we will do the following

 - do a global s/O_SYNC/O_DSYNC/g over the whole kernel tree
 - add a this to include/asm-generic/fcntl.h and in modified form
   to arch headers not using it:

#ifndef O_FULLSYNC
#define O_FULLSYNC	02000000
#endif

#ifndef O_RSYNC
#define O_RSYNC		04000000
#endif

#define O_SYNC	(O_FULLSYNC|O_DSYNC)

 - during the normal merge window I will add a real implementation for
   for O_FULLSYNC and O_RSYNC

P.S. better naming suggestions for O_FULLSYNC welcome