Re: [Qemu-devel] [PATCH] monitor: postpone monitor_qmp_cleanup_queues

[Markus Armbruster]

Stefan Hajnoczi <address@hidden> writes:

> On Fri, Jun 08, 2018 at 12:42:35PM +0800, Peter Xu wrote:
>> On Thu, Jun 07, 2018 at 01:53:01PM +0200, Markus Armbruster wrote:
>> > Peter Xu <address@hidden> writes:
>> > 
>> > > Previously we cleanup the queues when we got CLOSED event.  It was used
>> > 
>> > we clean up
>> > 
>> > > to make sure we won't leftover replies/events of a old client to a new
>> > 
>> > we won't send leftover replies/events of an old client
>> > 
>> > > client.  Now this patch postpones that until OPENED.
>> > 
>> > What if OPENED never comes?
>> 
>> Then we clean that up until destruction of the monitor.  IMHO it's
>> fine, but I'm not sure whether that's an overall acceptable approach.
>
> I think this patch fixes the problem at the wrong level.  Marc-André's
> fix seemed like a cleaner solution.

Is it the right solution?

I proposed another one:

[...]
>> > Here's what I think we should do on such EOF:
>> > 
>> > 1. Shut down input
>> > 
>> >    Stop reading input.  If input has its own file descriptor (as opposed
>> >    to a read/write fd shared with output), close it.
>> > 
>> > 2. Flush output
>> > 
>> >    Continue to write output until the queue becomes empty or we run into
>> >    an error (such as EPIPE, telling us the output's consumer went away).
>> >    Works exactly as before, except we proceed to step 3 when the queue

exactly as before EOF

>> >    becomes empty.
>> > 
>> > 3. Shut down output
>> > 
>> >    Close the output file descriptor.