[Sheepdog] [QEMU PATCH] sheepdog: add cache flush support

[Christoph Hellwig]

On Wed, Nov 16, 2011 at 02:07:07PM +0900, MORITA Kazutaka wrote:
> At Tue, 15 Nov 2011 17:06:52 -0500,
> Christoph Hellwig wrote:
> > 
> > This patch implement support for writeback-style cache in the sheepdog
> > protocol.  The SD_OP_FLUSH_VDI command will flush all data for the
> > referenced VDI to stable storage.
> > 
> > XXX: we'll need to figure out if the sheep server actually support this
> > command somehow.
> 
> If we increment SD_PROTO_VER, the sheep daemon should return
> SD_RES_VER_MISMATCH error when opening the VDI.

And then revert to trying the old protocol revision if it fails?  Sounds
like that would be worth a try.