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Date: Mon, 14 Mar 2011 18:16:27 +0100
From: Christoph Hellwig <hch@lst.de>
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Subject: [Qemu-devel] Re: Write cache enable from guest at runtime
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, Christoph Hellwig <hch@lst.de>, Prerna Saxena <prerna@linux.vnet.ibm.com>

On Mon, Mar 14, 2011 at 05:07:57PM +0000, Stefan Hajnoczi wrote:
> Hi Christoph,
> I have written up thoughts on write cache enable, including a
> workaround to change O_SYNC on a file without kernel changes:
> 
> http://wiki.qemu.org/Features/WriteCacheEnable
> 
> Guest ability to control write cache enable is useful and I'd like to
> see it in QEMU soon.  Any thoughts about what I've posted?  Care to
> submit your patches?

I have patches using Prerna's close and reopen method almost ready for posting.
Still fighting a bit with the new virtio code to wire it up.

Unlike your variant I actually added a generic change config request type,
which allows to re-use it for other runtime controllable features later.