On 03/30/2017 03:26 AM, Greg Kurz wrote: > If a client tries to flush the same outstanding request several times, only > the first flush completes. Subsequent ones keep waiting for the request > completion in v9fs_flush() and, therefore, leak a PDU. This will cause QEMU > to hang when draining active PDUs the next time the device is reset.
Since this fixes a hang, is it 2.9 material?
>
> Let have each flush request wake up the next one if any. The last waiter
> frees the cancelled PDU.
>
> Signed-off-by: Greg Kurz <gr...@kaod.org>
> ---
> hw/9pfs/9p.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
Reviewed-by: Eric Blake <ebl...@redhat.com>
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 48babce836b6..ef47a0a5ad6f 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -2387,8 +2387,10 @@ static void coroutine_fn v9fs_flush(void *opaque)
> * Wait for pdu to complete.
> */
> qemu_co_queue_wait(&cancel_pdu->complete, NULL);
> - cancel_pdu->cancelled = 0;
> - pdu_free(cancel_pdu);
> + if (!qemu_co_queue_next(&cancel_pdu->complete)) {
> + cancel_pdu->cancelled = 0;
> + pdu_free(cancel_pdu);
> + }
> }
> pdu_complete(pdu, 7);
> }
>
>
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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