md/004: add unmap write zeroes tests

The MD linear and RAID0 drivers in the Linux kernel now support the
unmap write zeroes operation. Test block device unmap write zeroes sysfs
interface with these two stacked devices. The sysfs parameters should
inherit from the underlying SCSI device. We can disable write zeroes
support by setting /sys/block/md<X>/queue/write_zeroes_unmap_max_bytes
to zero.

Signed-off-by: Zhang Yi <[email protected]>
[Shin'ichiro: noted kernel commit, fixed rc reference and mdadm check]
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>

Author: zhangyi089

tests/md/004

@@ -0,0 +1,98 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2025 Huawei.
+#
+# Test block device unmap write zeroes sysfs interface with MD devices. This is
+# the regression test for the kernel commit f0bd03832f5c ("md: init
+# queue_limits->max_hw_wzeroes_unmap_sectors parameter").
+
+. tests/md/rc
+. common/scsi_debug
+
+DESCRIPTION="test unmap write zeroes sysfs interface with MD devices"
+QUICK=1
+
+requires() {
+	_have_scsi_debug
+	_have_driver linear
+	_have_driver raid0
+}
+
+setup_test_device() {
+	local dev_0 dev_1 dpath
+	local raid_level=$1
+	local scsi_debug_params=(
+		num_tgts=1
+		add_host=2
+		per_host_store=true
+		"${@:2}"
+	)
+
+	if ! _configure_scsi_debug "${scsi_debug_params[@]}"; then
+		return 1
+	fi
+
+	if [[ ! -f /sys/block/${SCSI_DEBUG_DEVICES[0]}/queue/write_zeroes_unmap_max_hw_bytes ]]; then
+		_exit_scsi_debug
+		return $TO_SKIP
+	fi
+
+	dev_0="/dev/${SCSI_DEBUG_DEVICES[0]}"
+	dev_1="/dev/${SCSI_DEBUG_DEVICES[1]}"
+	mdadm --create /dev/md/blktests_md --level="$raid_level" --raid-devices=2 \
+		--force --run "${dev_0}" "${dev_1}" 2> /dev/null 1>&2
+
+	dpath=$(_real_dev /dev/md/blktests_md)
+	echo "${dpath##*/}"
+}
+
+cleanup_test_device() {
+	mdadm --stop /dev/md/blktests_md 2> /dev/null 1>&2
+	_exit_scsi_debug
+}
+
+test() {
+	echo "Running ${TEST_NAME}"
+
+	local dname
+
+	for raid_level in linear raid0; do
+		# disable WRITE SAME with unmap
+		dname=$(setup_test_device $raid_level lbprz=0)
+		ret=$?
+		if ((ret)); then
+			if ((ret == TO_SKIP)); then
+				SKIP_REASONS+=("kernel does not support unmap write zeroes sysfs interface")
+			fi
+			return 1
+		fi
+
+		umap_hw_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_unmap_max_hw_bytes")"
+		umap_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_unmap_max_bytes")"
+		if [[ $umap_hw_bytes -ne 0 || $umap_bytes -ne 0 ]]; then
+			echo "$raid_level: Test disable WRITE SAME with unmap failed."
+		fi
+		cleanup_test_device
+
+		# enable WRITE SAME with unmap
+		if ! dname=$(setup_test_device $raid_level lbprz=1 lbpws=1); then
+			return 1
+		fi
+
+		zero_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_max_bytes")"
+		umap_hw_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_unmap_max_hw_bytes")"
+		umap_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_unmap_max_bytes")"
+		if [[ $umap_hw_bytes -ne $zero_bytes || $umap_bytes -ne $zero_bytes ]]; then
+			echo "$raid_level: Test enable WRITE SAME with unmap failed."
+		fi
+
+		echo 0 > "/sys/block/$dname/queue/write_zeroes_unmap_max_bytes"
+		umap_bytes="$(cat "/sys/block/$dname/queue/write_zeroes_unmap_max_bytes")"
+		if [[ $umap_bytes -ne 0 ]]; then
+			echo "$raid_level: Test manually disable WRITE SAME with unmap failed."
+		fi
+		cleanup_test_device
+	done
+
+	echo "Test complete"
+}

tests/md/004.out

@@ -0,0 +1,2 @@
+Running md/004
+Test complete