Re: [Qemu-devel] [PATCH v2] blockdev: reset werror/rerror on drive_del

[Stefan Hajnoczi <stefanha@redhat.com>]

On Wed, Jun 05, 2013 at 10:33:14AM +0200, Stefan Hajnoczi wrote:
> Paolo Bonzini <pbonzini@redhat.com> suggested the following test case:
> 
> 1. Launch a guest and wait at the GRUB boot menu:
> 
>   qemu-system-x86_64 -enable-kvm -m 1024 \
>    -drive if=none,cache=none,file=test.img,id=foo,werror=stop,rerror=stop
>    -device virtio-blk-pci,drive=foo,id=virtio0,addr=4
> 
> 2. Hot unplug the device:
> 
>   (qemu) drive_del foo
> 
> 3. Select the first boot menu entry
> 
> Without this patch the guest pauses due to ENOMEDIUM.  The guest is
> stuck in a continuous pause loop since the I/O request is retried and
> fails immediately again when the guest is resumed.
> 
> With this patch the error is reported to the guest.
> 
> Note that this scenario actually happens sometimes during libvirt disk
> hot unplug, where device_del is followed by drive_del.  I/O may still be
> submitted to the drive after drive_del if the guest does not process the
> PCI hot unplug notification.
> 
> Reported-by: Dafna Ron <dron@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  blockdev.c      | 4 ++++
>  hmp-commands.hx | 2 ++
>  2 files changed, 6 insertions(+)

Applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan