Re: [Qemu-devel] [PATCH v3 06/12] nbd-server: Clear "can_read" when "device io" blocker is set

[Fam Zheng <famz@redhat.com>]

On Mon, 05/18 20:35, Max Reitz wrote:
> On 15.05.2015 08:04, Fam Zheng wrote:
> >So that NBD export cannot submit IO during bdrv_drain_all().
> >
> >Signed-off-by: Fam Zheng <famz@redhat.com>
> >---
> >  nbd.c | 18 ++++++++++++++++++
> >  1 file changed, 18 insertions(+)
> 
> But can_read is not cleared until nbd_update_can_read() is called, which is
> only in nbd_request_get(), nbd_request_put(), and nbd_co_receive_request(),
> which are all called from nbd_trip() - so the one request which clears
> can_read will most probably be itself processed.
> 
> Maybe we should call nbd_update_can_read() in nbd_op_blocker_changed(), for
> all clients of the export? Or just once somewhere at the beginning of
> processing a request, and if io_blocked is set, just yield...

I think you're right. I'll fix that.

Fam