Re: [PATCH] io_uring: retry in case of short read on block device

[Ming Lei <ming.lei@redhat.com>]

On Sat, Aug 21, 2021 at 11:07:51PM +0800, Ming Lei wrote:
> In case of buffered reading from block device, when short read happens,
> we should retry to read more, otherwise the IO will be completed
> partially, for example, the following fio expects to read 2MB, but it
> can only read 1M or less bytes:
> 
>     fio --name=onessd --filename=/dev/nvme0n1 --filesize=2M \
> 	--rw=randread --bs=2M --direct=0 --overwrite=0 --numjobs=1 \
> 	--iodepth=1 --time_based=0 --runtime=2 --ioengine=io_uring \
> 	--registerfiles --fixedbufs --gtod_reduce=1 --group_reporting
> 
> Fix the issue by allowing short read retry for block device, which sets
> FMODE_BUF_RASYNC really.
> 
> Fixes: 9a173346bd9e ("io_uring: fix short read retries for non-reg files")
> Cc: Pavel Begunkov <asml.silence@gmail.com>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>

Hello Jens and Pavel,

Any comments on this fix?


Thanks, 
Ming