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Re: [Qemu-devel] [PATCH] qga-win: don't hang if vss hold writes timeout
From: |
Chen Hanxiao |
Subject: |
Re: [Qemu-devel] [PATCH] qga-win: don't hang if vss hold writes timeout |
Date: |
Sat, 23 Sep 2017 11:11:13 +0800 (CST) |
在 2017-09-23 05:12:20,"Tomoki Sekiyama" <address@hidden> 写道:
>
> Thanks for your patch.
> Which version of Windows have you found the hang?
>
>
I tested on win08, win 08 r2 and win2012.
QGA versions:
Use the latest qga-win from
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-qemu-ga/qemu-ga-win-7.4.5-1/
and stable branch from
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/virtio-win-0.1.126-2/virtio-win-0.1.126.iso
All of them have the same behavior.
How to reproduce:
Copy a big file in guest (from d: to c:), then do fsfreeze when IO is in
progress.
At this time, we had a very chance to see that qga hang for a long time.
Libvirt will not recieve a reply.
qemu-ga service even don't answer `net stop` command.
Regards,
- Chen
> Regards,
> Tomoki
>
>
> 2017-09-22 11:46 GMT+09:00 Chen Hanxiao <address@hidden>:
>
> From: Chen Hanxiao <address@hidden>
>
>
>
> 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 <address@hidden>
>
> ---
>
> 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();
>
> }