Commit 60cf8637 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

selftests/ublk: add test for async partition scan 



Add test_generic_15.sh to verify that async partition scan prevents
IO hang when reading partition tables.

The test creates ublk devices with fault_inject target and very large
delay (60s) to simulate blocked partition table reads, then kills the
daemon to verify proper state transitions without hanging:

1. Without recovery support:
   - Create device with fault_inject and 60s delay
   - Kill daemon while partition scan may be blocked
   - Verify device transitions to DEAD state

2. With recovery support (-r 1):
   - Create device with fault_inject, 60s delay, and recovery
   - Kill daemon while partition scan may be blocked
   - Verify device transitions to QUIESCED state

Before the async partition scan fix, killing the daemon during
partition scan would cause deadlock as partition scan held ub->mutex
while waiting for IO. With the async fix, partition scan happens in
a work function and flush_work() ensures proper synchronization.

Add _add_ublk_dev_no_settle() helper function to skip udevadm settle,
which would otherwise hang waiting for partition scan events to
complete when partition table read is delayed.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7fc4da6a

tools/testing/selftests/ublk/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ TEST_PROGS += test_generic_11.sh 
TEST_PROGS += test_generic_12.sh

TEST_PROGS += test_generic_13.sh

TEST_PROGS += test_generic_14.sh

TEST_PROGS += test_generic_15.sh



TEST_PROGS += test_null_01.sh

TEST_PROGS += test_null_02.sh

tools/testing/selftests/ublk/test_common.sh

+12 −4
Original line number Diff line number Diff line
@@ -178,8 +178,9 @@ _have_feature() 
_create_ublk_dev() {

	local dev_id;

	local cmd=$1

	local settle=$2



	shift 1

	shift 2



	if [ ! -c /dev/ublk-control ]; then

		return ${UBLK_SKIP_CODE}
@@ -194,7 +195,10 @@ _create_ublk_dev() { 
		echo "fail to add ublk dev $*"

		return 255

	fi



	if [ "$settle" = "yes" ]; then

		udevadm settle

	fi



	if [[ "$dev_id" =~ ^[0-9]+$ ]]; then

		echo "${dev_id}"
@@ -204,14 +208,18 @@ _create_ublk_dev() { 
}



_add_ublk_dev() {

	_create_ublk_dev "add" "$@"

	_create_ublk_dev "add" "yes" "$@"

}



_add_ublk_dev_no_settle() {

	_create_ublk_dev "add" "no" "$@"

}



_recover_ublk_dev() {

	local dev_id

	local state



	dev_id=$(_create_ublk_dev "recover" "$@")

	dev_id=$(_create_ublk_dev "recover" "yes" "$@")

	for ((j=0;j<20;j++)); do

		state=$(_get_ublk_dev_state "${dev_id}")

		[ "$state" == "LIVE" ] && break

tools/testing/selftests/ublk/test_generic_15.sh

0 → 100755
+68 −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_15"

ERR_CODE=0



_test_partition_scan_no_hang()

{

	local recovery_flag=$1

	local expected_state=$2

	local dev_id

	local state

	local daemon_pid

	local start_time

	local elapsed



	# Create ublk device with fault_inject target and very large delay

	# to simulate hang during partition table read

	# --delay_us 60000000 = 60 seconds delay

	# Use _add_ublk_dev_no_settle to avoid udevadm settle hang waiting

	# for partition scan events to complete

	if [ "$recovery_flag" = "yes" ]; then

		echo "Testing partition scan with recovery support..."

		dev_id=$(_add_ublk_dev_no_settle -t fault_inject -q 1 -d 1 --delay_us 60000000 -r 1)

	else

		echo "Testing partition scan without recovery..."

		dev_id=$(_add_ublk_dev_no_settle -t fault_inject -q 1 -d 1 --delay_us 60000000)

	fi



	_check_add_dev "$TID" $?



	# The add command should return quickly because partition scan is async.

	# Now sleep briefly to let the async partition scan work start and hit

	# the delay in the fault_inject handler.

	sleep 1



	# Kill the ublk daemon while partition scan is potentially blocked

	# And check state transitions properly

	start_time=${SECONDS}

	daemon_pid=$(_get_ublk_daemon_pid "${dev_id}")

	state=$(__ublk_kill_daemon "${dev_id}" "${expected_state}")

	elapsed=$((SECONDS - start_time))



	# Verify the device transitioned to expected state

	if [ "$state" != "${expected_state}" ]; then

		echo "FAIL: Device state is $state, expected ${expected_state}"

		ERR_CODE=255

		${UBLK_PROG} del -n "${dev_id}" > /dev/null 2>&1

		return

	fi

	echo "PASS: Device transitioned to ${expected_state} in ${elapsed}s without hanging"



	# Clean up the device

	${UBLK_PROG} del -n "${dev_id}" > /dev/null 2>&1

}



_prep_test "partition_scan" "verify async partition scan prevents IO hang"



# Test 1: Without recovery support - should transition to DEAD

_test_partition_scan_no_hang "no" "DEAD"



# Test 2: With recovery support - should transition to QUIESCED

_test_partition_scan_no_hang "yes" "QUIESCED"



_cleanup_test "partition_scan"

_show_result $TID $ERR_CODE