Re: adding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers
[Posted September 1, 2009 by corbet]
| From: |
| Christoph Hellwig <hch-AT-infradead.org> |
| To: |
| Ulrich Drepper <drepper-AT-redhat.com> |
| Subject: |
| Re: adding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers |
| Date: |
| Fri, 28 Aug 2009 17:08:38 -0400 |
| Cc: |
| Christoph Hellwig <hch-AT-infradead.org>,
Jamie Lokier <jamie-AT-shareable.org>,
linux-fsdevel-AT-vger.kernel.org, linux-kernel-AT-vger.kernel.org,
torvalds-AT-linux-foundation.org |
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
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