Re: [PATCH, RFC] virtio_blk: add cache flush command

Christoph Hellwig
2009-05-18T12:04:01Z

On Mon, May 11, 2009 at 01:29:06PM -0500, Anthony Liguori wrote:
> >It don't think we realistically can.
>
> Maybe two fds? One open in O_SYNC and one not. Is such a thing sane?

O_SYNC and O_DIRECT currently behave exactly in the same way. In none
of the filesystem I've looked at there is an explicit cache flush,
but all send down a barrier which gives you an implicit cache flush
with the way barriers are implemented.