PI test on filesystem

[MorningWeicheng]

Because io_uring_cmd can only run on character devices, I used the libaio and io_uring engines to test PI (Protection Information) on a filesystem. I found that libaio cannot use parameters such as pi_act, while io_uring supports commands like:
fio -filename=/mnt/f1 -iodepth=128 -rw=write -bs=128k -numjobs=1 -name=128k_seq_WR_1job_QD128 -ioengine=io_uring -direct=0 -runtime=600s -time_based=1 -ramp_time=60 -group_reporting -pi_act=1 -pi_chk=GUARD,APPTAG,REFTAG -md_per_io_size=0 -buffer_compress_chunk=4k -buffer_compress_percentage=0 -thread=1
However, the actual PRINFO value in DW12 was still b'1000' .
So how can I perform file I/O operations with custom PI parameters?

[vincentkfu]

PI support is only available for block devices and not files.

[MorningWeicheng]

I still have a question:
Fio.readthedocs shows that PI-related parameters (e.g., pi_act/pi_chk) only work with the io_uring_cmd/xnvme engines. Does the io_uring engine support PI, or will it do so in the future, if not, why?
Thx~

[vincentkfu]

With kernel 6.17 and later the io_uring ioengine supports protection information with NVMe block devices.
We should update the documentation to reflect this.
There are some recent efforts to support PI on XFS: https://lore.kernel.org/linux-block/20260128161517.666412-1-hch@lst.de/T/#m5a5f8205998afccc8a57589abe85222a467fc915