Hi!
01.02.2021 15:07, Peng Liang wrote:
Hi,
I encountered the problem months ago too. Could we move the creation of
the block job (block_job_create) before appending the new bs to
mirror_top_bs (bdrv_append) as I wrote in [*]? I found that after
bdrv_append, qemu will use mirror_top_bs to do write. And when writing,
qemu will use bs->opaque, which maybe NULL.
[*]
http://patchwork.ozlabs.org/project/qemu-devel/patch/20200826131910.1879079-1-liangpen...@huawei.com/
In this patch you create job over original bs, when jobs are normally created over
job-filter bs. I don't know is it wrong, but it at least requires some research,
and probably the code that removes the filter should be adjusted somehow. Also,
you make bs->opaque be non-zero. But still, job is not fully initialized, and
some another problem may occur. So, do we create job prior to filter insertion or
after it, parallel io requests to bs should not interrupt mirror_start_job(). So I
think Michael's patch is closer to real problem to fix.
--
Best regards,
Vladimir
