[libvirt] [PATCH] Ensure stream is aborted when exiting console

[Dave Allan]

On Tue, Aug 16, 2011 at 04:26:03PM -0700, Daniel P. Berrange wrote:
> On Tue, Aug 16, 2011 at 02:52:07PM -0400, Dave Allan wrote:
> > On Tue, Aug 16, 2011 at 11:15:04AM -0700, Daniel P. Berrange wrote:
> > > On Mon, Aug 15, 2011 at 02:19:27PM -0400, Dave Allan wrote:
> > > > On Mon, Aug 15, 2011 at 10:12:54AM -0700, Daniel P. Berrange wrote:
> > > > > From: "Daniel P. Berrange" <berrange at redhat.com>
> > > > > 
> > > > > After running 'virsh console' in interactive mode, there was a
> > > > > missing call to virStreamAbort, which meant the server kept the
> > > > > stream resources open
> > > > 
> > > > The combination of this patch and the other stream related patch makes
> > > > the problem I was seeing of garbled console following multiple console
> > > > connect/disconnects go away, but another problem remains in this area.
> > > > After connecting to the console in interactive virsh and
> > > > disconnecting, I often see all subsequent commands fail:
> > > > 
> > > > virsh # dominfo foo
> > > > error: failed to get domain 'foo'
> > > > error: An error occurred, but the cause is unknown
> > > > 
> > > > virsh # dominfo foo
> > > > error: failed to get domain 'foo'
> > > > error: no call waiting for reply with prog 536903814 vers 1 serial 300
> > > > 
> > > > virsh # define bar.xml
> > > > error: Failed to define domain from bar.xml
> > > > error: no call waiting for reply with prog 536903814 vers 1 serial 301
> > > > 
> > > > Closing and reopening the interactive virsh session makes the problem
> > > > go away.
> > > > 
> > > > Powering down the guest while the console is connected has made the
> > > > problem 100% reproducible in the 4 or 5 tries I've given it.
> > > 
> > > Yeah this is a regression. We were accidentally sending back two
> > > stream abort RPC packets in some scenarios (with race condition).
> > > 
> > > I've posted a patch to fix it
> > 
> > It does indeed fix the failure on domain shutdown, but there is still
> > a problem related to high volumes of console output.  If I get on the
> > console and execute:
> > 
> > while true ; do echo -n "The quick brown fox jumped over the lazy
> > dogs.  The quick brown fox jumped over the lazy dogs.  "; done
> > 
> > and exit the console while the output is spraying, I still see a
> > failure:
> > 
> >  the lazy dogs.  The quick brown fox jumped over the lazy dogs.  The
> >  quick brown fox jumped over t
> > virsh # console foo
> > error: failed to get domain 'foo'
> > error: An error occurred, but the cause is unknown
> > 
> > virsh # console foo
> > error: failed to get domain 'foo'
> > error: An error occurred, but the cause is unknown
> > 
> > virsh # console foo
> > error: failed to get domain 'foo'
> > error: no call waiting for reply with prog 536903814 vers 1 serial 6
> > 
> > virsh # 
> > 
> > 
> > BTW, I noticed this first when exiting the console while boot messages
> > were being output; I'm not *trying* to break it, and many thanks for
> > looking into all this.  :)
> 
> This time i found a bug that pre-dated my RPC refactoring :-)
> 
> Sent 2 more patches....

Ok, that makes everything work much better, with one smaller problem
remaining: if there is output flowing to the console at the time that
I connect, I usually don't see it until I've sent input to the
console, at which point it starts flowing.  Often on the first
connection to the console output will start flowing immediately, but
subsequent connections within a single virsh session will not show
output until input is sent.  Occasionaly output will start after 10 or
15 seconds, but at other times I've let it sit over a minute with no
output.  Sending input always resumes the output.

Dave