[libvirt] [PATCH] Fix synchronous reading of stream data

[Dave Allan]

On Wed, Sep 21, 2011 at 02:54:38PM +0100, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
> 
> commit 984840a2c292402926ad100aeea33f8859ff31a9 removed the
> notification of waiting calls when VIR_NET_CONTINUE messages
> arrive. This was to fix the case of a virStreamAbort() call
> being prematurely notified of completion.
> 
> The problem is that sometimes there are dummy calls from a
> virStreamRecv() call waiting that *do* need to be notified.
> 
> These dummy calls should have a status VIR_NET_CONTINUE. So
> re-add the notification upon VIR_NET_CONTINUE, but only if
> the waiter also has a status of VIR_NET_CONTINUE.

No regressions with my console script with that patch applied, so ACK
in that regard.  I have not reviewed it otherwise.

Dave

> * src/rpc/virnetclient.c: Notify waiting call if stream data
>   arrives
> * src/rpc/virnetclientstream.c:  Mark dummy stream read packet
>   with status VIR_NET_CONTINUE
> ---
>  src/rpc/virnetclient.c       |   10 ++++++++++
>  src/rpc/virnetclientstream.c |    1 +
>  2 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
> index 055361d..b2c528a 100644
> --- a/src/rpc/virnetclient.c
> +++ b/src/rpc/virnetclient.c
> @@ -627,6 +627,15 @@ static int virNetClientCallDispatchStream(virNetClientPtr client)
>      case VIR_NET_CONTINUE: {
>          if (virNetClientStreamQueuePacket(st, &client->msg) < 0)
>              return -1;
> +
> +        if (thecall && thecall->expectReply) {
> +            if (thecall->msg->header.status == VIR_NET_CONTINUE) {
> +                VIR_DEBUG("Got a synchronous confirm");
> +                thecall->mode = VIR_NET_CLIENT_MODE_COMPLETE;
> +            } else {
> +                VIR_DEBUG("Not completing call with status %d", thecall->msg->header.status);
> +            }
> +        }
>          return 0;
>      }
>  
> @@ -1189,6 +1198,7 @@ int virNetClientSend(virNetClientPtr client,
>      int ret = -1;
>  
>      if (expectReply &&
> +        (msg->bufferLength != 0) &&
>          (msg->header.status == VIR_NET_CONTINUE)) {
>          virNetError(VIR_ERR_INTERNAL_ERROR, "%s",
>                      _("Attempt to send an asynchronous message with a synchronous reply"));
> diff --git a/src/rpc/virnetclientstream.c b/src/rpc/virnetclientstream.c
> index 2cc84d4..4cd0295 100644
> --- a/src/rpc/virnetclientstream.c
> +++ b/src/rpc/virnetclientstream.c
> @@ -400,6 +400,7 @@ int virNetClientStreamRecvPacket(virNetClientStreamPtr st,
>          msg->header.type = VIR_NET_STREAM;
>          msg->header.serial = st->serial;
>          msg->header.proc = st->proc;
> +        msg->header.status = VIR_NET_CONTINUE;
>  
>          VIR_DEBUG("Dummy packet to wait for stream data");
>          virMutexUnlock(&st->lock);
> -- 
> 1.7.6.2
>