Re: [Qemu-devel] [PATCH] qga-win: don't hang if vss hold writes timeout

[Tomoki Sekiyama <tomoki.sekiyama@gmail.com>]

Thanks for your patch.
Which version of Windows have you found the hang?

Regards,
Tomoki

2017-09-22 11:46 GMT+09:00 Chen Hanxiao <chen_han_xiao@126.com>:

> From: Chen Hanxiao <chenhanxiao@gmail.com>
>
> When VM is in a heavy IO, if the command "guest-fsfreeze-freeze"
> is executed, VSS may timeout when trying to hold writes.
>
> Inside guest, Event ID 12298(VSS_ERROR_HOLD_WRITES_TIMEOUT)
> is logged in the Event Viewer.
>
> At that time, if we call AbortBackup, qga may hang forever.
>
> This patch will solve this issues.
>
> Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
> ---
>  qga/vss-win32/requester.cpp | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
> index 301762d..3d9c971 100644
> --- a/qga/vss-win32/requester.cpp
> +++ b/qga/vss-win32/requester.cpp
> @@ -419,6 +419,16 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
>              break;
>          }
>      }
> +
> +    if (wait_status == WAIT_TIMEOUT) {
> +        err_set(errset, E_FAIL,
> +                "timeout when try to receive Frozen event from VSS
> provider");
> +        /* If we are here, VSS had timeout.
> +         * Don't call AbortBackup, just return directly.
> +         */
> +        goto out1;
> +    }
> +
>      if (wait_status != WAIT_OBJECT_0) {
>          err_set(errset, E_FAIL,
>                  "couldn't receive Frozen event from VSS provider");
> @@ -432,6 +442,8 @@ out:
>      if (vss_ctx.pVssbc) {
>          vss_ctx.pVssbc->AbortBackup();
>      }
> +
> +out1:
>      requester_cleanup();
>      CoUninitialize();
>  }
> --
> 2.7.5
>
>