Re: [Qemu-devel] [PATCH] Flush pending AIO on reboot and shutdown.

[Anthony Liguori <anthony@codemonkey.ws>]

Gleb Natapov wrote:
> If there is outstanding IDE IO when BIOS starts execution then IDE
> commands sent by BIOS will interfere with it and will leave IDE
> subsystem in unpredictable state. This can happen when system reboots
> unexpectedly without waiting for IO completion. Flushing IO before exit
> prevents data lose.
>
> Signed-off-by: Gleb Natapov <gleb@qumranet.com>
> ---
>
>  vl.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/vl.c b/vl.c
> index e42ae64..afa2a3a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -7553,6 +7553,7 @@ static int main_loop(void)
>              if (reset_requested) {
>                  reset_requested = 0;
>                  qemu_system_reset();
> +                qemu_aio_flush();
>   

Perhaps the aio block layer should do qemu_register_reset() with a 
handler that does a flush.

Regards,

Anthony Liguori

>                  ret = EXCP_INTERRUPT;
>              }
>              if (powerdown_requested) {
> @@ -9178,6 +9179,7 @@ int main(int argc, char **argv)
>      }
>  
>      main_loop();
> +    qemu_aio_flush();
>      quit_timers();
>  
>  #if !defined(_WIN32)
>
>
>
>