[sheepdog] [PATCH v2 1/2] sheep: make 'collie vdi delete' wait for response synchronously

[Christoph Hellwig]

On Wed, Jun 27, 2012 at 11:21:39PM +0800, levin li wrote:
> From: levin li <xingke.lwp at taobao.com>
> 
> VDI deletion work should response to client until all the objects
> have been deleted just as what file system does, this patch makes
> it call req_done to send back a response until deletion_one_done()
> has been called.

I'm a bit worried about the refcount not being an uatomic_t - we 
increment it from the worker thread, and while it can't get decremented
at that time yet we'd at least need a barrier for some historic or
theoretical memory models.

Except for that the changes look good to me.