Commit 723977ca authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

selftests: ublk: add generic_01 for verifying sequential IO order 



block layer, ublk and io_uring might re-order IO in the past

- plug

- queue ublk io command via task work

Add one test for verifying if sequential WRITE IO is dispatched in order.

- null target is taken, so we can just observe io order from
`tracepoint:block:block_rq_complete` which represents the dispatch order

- WRITE IO is taken because READ may come from system-wide utility

Cc: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250322093218.431419-2-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ffde32a4

tools/testing/selftests/ublk/Makefile

+3 −1
Original line number Diff line number Diff line
@@ -3,7 +3,9 @@ 
CFLAGS += -O3 -Wl,-no-as-needed -Wall -I $(top_srcdir)

LDLIBS += -lpthread -lm -luring



TEST_PROGS := test_null_01.sh

TEST_PROGS := test_generic_01.sh



TEST_PROGS += test_null_01.sh

TEST_PROGS += test_loop_01.sh

TEST_PROGS += test_loop_02.sh

TEST_PROGS += test_loop_03.sh

tools/testing/selftests/ublk/test_common.sh

+22 −0
Original line number Diff line number Diff line
@@ -3,6 +3,26 @@ 


UBLK_SKIP_CODE=4



_have_program() {

	if command -v "$1" >/dev/null 2>&1; then

		return 0

	fi

	return 1

}



_get_disk_dev_t() {

	local dev_id=$1

	local dev

	local major

	local minor



	dev=/dev/ublkb"${dev_id}"

	major=$(stat -c '%Hr' "$dev")

	minor=$(stat -c '%Lr' "$dev")



	echo $(( (major & 0xfff) << 20 | (minor & 0xfffff) ))

}



_create_backfile() {

	local my_size=$1

	local my_file
@@ -121,6 +141,7 @@ _check_add_dev() 


_cleanup_test() {

	"${UBLK_PROG}" del -a

	rm -f "$UBLK_TMP"

}



_have_feature()
@@ -216,6 +237,7 @@ _ublk_test_top_dir() 
	cd "$(dirname "$0")" && pwd

}



UBLK_TMP=$(mktemp ublk_test_XXXXX)

UBLK_PROG=$(_ublk_test_top_dir)/kublk

UBLK_TEST_QUIET=1

UBLK_TEST_SHOW_RESULT=1

tools/testing/selftests/ublk/test_generic_01.sh

0 → 100755
+44 −0
Original line number Diff line number Diff line 
#!/bin/bash

# SPDX-License-Identifier: GPL-2.0



. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh



TID="generic_01"

ERR_CODE=0



if ! _have_program bpftrace; then

	exit "$UBLK_SKIP_CODE"

fi



_prep_test "null" "sequential io order"



dev_id=$(_add_ublk_dev -t null)

_check_add_dev $TID $?



dev_t=$(_get_disk_dev_t "$dev_id")

bpftrace trace/seq_io.bt "$dev_t" "W" 1 > "$UBLK_TMP" 2>&1 &

btrace_pid=$!

sleep 2



if ! kill -0 "$btrace_pid" > /dev/null 2>&1; then

	_cleanup_test "null"

	exit "$UBLK_SKIP_CODE"

fi



# run fio over this ublk disk

fio --name=write_seq \

    --filename=/dev/ublkb"${dev_id}" \

    --ioengine=libaio --iodepth=16 \

    --rw=write \

    --size=512M \

    --direct=1 \

    --bs=4k > /dev/null 2>&1

ERR_CODE=$?

kill "$btrace_pid"

wait

if grep -q "io_out_of_order" "$UBLK_TMP"; then

	cat "$UBLK_TMP"

	ERR_CODE=255

fi

_cleanup_test "null"

_show_result $TID $ERR_CODE

tools/testing/selftests/ublk/trace/seq_io.bt

0 → 100644
+25 −0
Original line number Diff line number Diff line 
/*

	$1: 	dev_t

	$2: 	RWBS

	$3:     strlen($2)

*/

BEGIN {

	@last_rw[$1, str($2)] = 0;

}

tracepoint:block:block_rq_complete

{

	$dev = $1;

	if ((int64)args.dev == $1 && !strncmp(args.rwbs, str($2), $3)) {

		$last = @last_rw[$dev, str($2)];

		if ((uint64)args.sector != $last) {

			printf("io_out_of_order: exp %llu actual %llu\n",

				args.sector, $last);

		}

		@last_rw[$dev, str($2)] = (args.sector + args.nr_sector);

	}

	@ios = count();

}



END {

	clear(@last_rw);

}