[pve-devel] applied: [PATCH v2 qemu-server] fix #4099: disable io_uring for virtual disks on CIFS storages

[Thomas Lamprecht]

On 27/10/2022 09:13, Fiona Ebner wrote:
> Since kernel 5.15, there is an issue with io_uring when used in
> combination with CIFS [0]. Unfortunately, the kernel developers did
> not suggest any way to resolve the issue and didn't comment on my
> proposed one. So for now, just disable io_uring when the storage is
> CIFS, like is done for other storage types that had problematic
> interactions.
> 
> It is rather easy to reproduce when writing large amounts of data
> within the VM. I used
> dd if=/dev/urandom of=file bs=1M count=1000
> to reproduce it consistently, but your mileage may vary.
> 
> Some forum reports about users running into the issue [1][2][3].
> 
> [0]: https://www.spinics.net/lists/linux-cifs/msg26734.html
> [1]: https://forum.proxmox.com/threads/109848/
> [2]: https://forum.proxmox.com/threads/110464/
> [3]: https://forum.proxmox.com/threads/111382/
> 
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
> 
> Changes from v1:
>     * Add 'fix #4099'-prefix to commit title.
> 
>  PVE/QemuServer.pm | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
>

really unfortunate indeed though, a kernel fix would be nicer,
but there's only so much time we can spent waiting on progress
there, so ...

applied, thanks!