Add test case from Stephen Zhang [1].

[1] https://lore.kernel.org/linux-bcache/CANubcdX7eNbH_bo4-f94DUbdiEbt04Vxy1MPyhm+CZyXB01FuQ@mail.gmail.com/

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 tests/bcache/002     | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/bcache/002.out |  2 ++
 2 files changed, 65 insertions(+)

diff --git a/tests/bcache/002 b/tests/bcache/002
new file mode 100644
index 000000000000..04892667ad1b
--- /dev/null
+++ b/tests/bcache/002
@@ -0,0 +1,63 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026 Daniel Wagner, SUSE Labs
+#
+# Test based on Stephen Zhang <starzhangzsd@gmail.com> test case
+# https://lore.kernel.org/linux-bcache/CANubcdX7eNbH_bo4-f94DUbdiEbt04Vxy1MPyhm+CZyXB01FuQ@mail.gmail.com/#t
+#
+# Test bcache for bio leaks in clone
+
+. tests/bcache/rc
+
+DESCRIPTION="test bcache for bio leaks in clone"
+
+requires() {
+	_bcache_requires
+	_have_fio
+	_have_program iostat
+}
+
+test_device_array() {
+	echo "Running ${TEST_NAME}"
+
+	if [[ ${#TEST_DEV_ARRAY[@]} -lt 2 ]]; then
+		SKIP_REASONS+=("requires at least 2 devices")
+		return 1
+	fi
+
+	_setup_bcache "${TEST_DEV_ARRAY[@]}"
+
+	local bcache_nodes bcache_dev bdev_name fio_pid
+
+	mapfile -t bcache_nodes < <(_create_bcache \
+				--cache "${TEST_DEV_ARRAY[0]##*/}" \
+				--bdev "${TEST_DEV_ARRAY[1]##*/}" \
+				--writeback)
+
+	bcache_dev="${bcache_nodes[0]}"
+	bdev_name="$(basename "${bcache_dev}")"
+	echo 1 > /sys/block/"${bdev_name}"/bcache/detach
+
+	state="$(cat /sys/block/"${bdev_name}"/bcache/state)"
+	echo "Device state: ${state}"
+
+	_run_fio_rand_io --filename="${bcache_dev}" --time_base \
+			--runtime=30 >> "$FULL" 2>&1 &
+	fio_pid=$!
+
+	sleep 5
+
+	local stats_line util
+	stats_line=$(iostat -x 1 2 "${bdev_name}" | grep -w "${bdev_name}" | tail -n 1)
+	util="$(echo "${stats_line}" | awk '{print $NF}')"
+
+	if (( $(echo "${util} > 1.0" | bc -l) )); then
+		echo "ERROR: Accounting leak detected!"
+	fi
+
+	{ pkill -f "fio.*${bcache_dev}"; wait "${fio_pid}"; } &> /dev/null
+
+	_remove_bcache --bcache "${bcache_nodes[@]}" \
+			--cache "${TEST_DEV_ARRAY[0]##*/}" \
+			--bdev "${TEST_DEV_ARRAY[1]##*/}"
+}
diff --git a/tests/bcache/002.out b/tests/bcache/002.out
new file mode 100644
index 000000000000..529c1a90b135
--- /dev/null
+++ b/tests/bcache/002.out
@@ -0,0 +1,2 @@
+Running bcache/002
+Device state: no cache

-- 
2.52.0