Re: [Qemu-devel] [Qemu-block] [PATCH for-2.11] throttle-groups: forget timer and schedule next TGM on detach

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Thu, Nov 16, 2017 at 11:21:50AM +0000, Stefan Hajnoczi wrote:
> tg->any_timer_armed[] must be cleared when detaching pending timers from
> the AioContext.  Failure to do so leads to hung I/O because it looks
> like there are still timers pending when in fact they have been removed.
> 
> Other ThrottleGroupMembers might have requests pending too so it's
> necessary to schedule the next TGM so it can set a timer.
> 
> This patch fixes hung I/O when QEMU is launched with drives that are in
> the same throttling group:
> 
>   (guest)$ dd if=/dev/zero of=/dev/vdb oflag=direct bs=512 &
>   (guest)$ dd if=/dev/zero of=/dev/vdc oflag=direct bs=512 &
>   (qemu) stop
>   (qemu) cont
>   ...I/O is stuck...
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  block/throttle-groups.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan

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