[pve-devel] applied: Re: [PATCH v2 qemu] io_uring: resubmit when result is -EAGAIN

Thomas Lamprecht t.lamprecht at proxmox.com
Thu Jul 29 17:59:01 CEST 2021

On 29/07/2021 11:50, Fabian Ebner wrote:
> Linux SCSI can throw spurious -EAGAIN in some corner cases in its
> completion path, which will end up being the result in the completed
> io_uring request.
> Resubmitting such requests should allow block jobs to complete, even
> if such spurious errors are encountered.
> Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
> ---
> Changes from v1:
>     * make it a patch for pve-qemu instead of the qemu submodule
>     * use v2 of the patch with a comment by Stefan Hajnoczi
>  ...uring-resubmit-when-result-is-EAGAIN.patch | 49 +++++++++++++++++++
>  debian/patches/series                         |  1 +
>  2 files changed, 50 insertions(+)
>  create mode 100644 debian/patches/extra/0002-block-io_uring-resubmit-when-result-is-EAGAIN.patch

applied, thanks!

For others regarding bump: while this is def. correct it actually increases the
likelihood of a kernel crash with old (<< pve-kernel-5.11.22-3-pve 5.11.22-6)
kernels. As now it was either a crash or a block job error, this patch basically
converts the block job errors into crashes on bad old kernel and into avoiding
a block job error on the OK behavior of resubmitting on EAGAIN on new kernels.
Those that saw neither crash nor block job errors won't notice a difference
either way.

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