On Tue, Dec 05, 2023 at 01:48:26AM -0500, tian...@smartx.com wrote:
> From: Tianren Zhang <tian...@smartx.com>
>
> The stop process is not finished until bdrv_flush_all
> is done. Some users (e.g., libvirt) detect the STOP
> event and invokes some lock release logic to revoke
> the disk lock held by current qemu when such event is
> emitted. In such case, if the bdrv_flush_all is after
> the stop event, it's possible that the disk lock is
> released while the qemu is still waiting for I/O.
> Therefore, it's better to have the stop event generated
> after the whole stop process is done, so we can
> guarantee to users that the stop process is finished
> when they get the STOP event.
>
> Change-Id: Ia2f95cd55edfdeb71ee2e04005ac216cfabffa22
Please don't include this in commit messages for patches posted.
QEMU does not use Gerrit and so this is irrelevant to upstream.
> Signed-off-by: Tianren Zhang <tian...@smartx.com>
> ---
> v2: do not call runstate_is_running twice
> ---
> system/cpus.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
Reviewed-by: Daniel P. Berrangé <berra...@redhat.com>
>
> diff --git a/system/cpus.c b/system/cpus.c
> index a444a747f0..49af0f92b5 100644
> --- a/system/cpus.c
> +++ b/system/cpus.c
> @@ -262,21 +262,24 @@ void cpu_interrupt(CPUState *cpu, int mask)
> static int do_vm_stop(RunState state, bool send_stop)
> {
> int ret = 0;
> + bool do_send_stop = false;
>
> if (runstate_is_running()) {
> runstate_set(state);
> cpu_disable_ticks();
> pause_all_vcpus();
> vm_state_notify(0, state);
> - if (send_stop) {
> - qapi_event_send_stop();
> - }
> + do_send_stop = send_stop;
> }
>
> bdrv_drain_all();
> ret = bdrv_flush_all();
> trace_vm_stop_flush_all(ret);
>
> + if (do_send_stop) {
> + qapi_event_send_stop();
> + }
> +
> return ret;
> }
With regards,
Daniel
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