[PATCH blktests v2] nbd: add a module load and device connect test

[Sun Ke <sunke32@huawei.com>]

This is a regression test for commit 06c4da89c24e
nbd: call genl_unregister_family() first in nbd_cleanup()

Two concurrent processes，one load and unlock nbd module
cyclically, the other one connect and disconnect nbd device cyclically.
Last for 10 seconds.

Signed-off-by: Sun Ke <sunke32@huawei.com>
---
v1->v2: 
1.change install/uninstall to load/unlock
2.use _have_modules instead

 tests/nbd/004     | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/nbd/004.out |  2 ++
 tests/nbd/rc      | 18 ++++++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100755 tests/nbd/004
 create mode 100644 tests/nbd/004.out

diff --git a/tests/nbd/004 b/tests/nbd/004
new file mode 100755
index 0000000..6b2c5ff
--- /dev/null
+++ b/tests/nbd/004
@@ -0,0 +1,52 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2022 Sun Ke
+#
+# Regression test for commit 06c4da89c24e
+# nbd: call genl_unregister_family() first in nbd_cleanup()
+
+. tests/nbd/rc
+
+DESCRIPTION="module load/unlock concurrently with connect/disconnect"
+QUICK=1
+
+requires() {
+	_have_modules
+}
+
+module_load_and_unlock() {
+	while true; do
+		modprobe nbd >/dev/null 2>&1
+		modprobe -r nbd >/dev/null 2>&1
+	done
+}
+
+connect_and_disconnect() {
+	while true; do
+		_netlink_connect >/dev/null 2>&1
+		_netlink_disconnect >/dev/null 2>&1
+	done
+}
+
+test() {
+	echo "Running ${TEST_NAME}"
+
+	_start_nbd_server_netlink
+
+	module_load_and_unlock &
+	pid1=$!
+	connect_and_disconnect &
+	pid2=$!
+
+	sleep 10
+	{
+		kill -9 $pid1
+		wait $pid1
+		kill -9 $pid2
+		wait $pid2
+	} 2>/dev/null
+
+	_stop_nbd_server_netlink
+	echo "Test complete"
+}
+
diff --git a/tests/nbd/004.out b/tests/nbd/004.out
new file mode 100644
index 0000000..05ced0c
--- /dev/null
+++ b/tests/nbd/004.out
@@ -0,0 +1,2 @@
+Running nbd/004
+Test complete
diff --git a/tests/nbd/rc b/tests/nbd/rc
index 118553c..b0e7d91 100644
--- a/tests/nbd/rc
+++ b/tests/nbd/rc
@@ -76,3 +76,21 @@ _stop_nbd_server() {
 	rm -f "${TMPDIR}/nbd.pid"
 	rm -f "${TMPDIR}/export"
 }
+
+_start_nbd_server_netlink() {
+	truncate -s 10G "${TMPDIR}/export"
+	nbd-server 8000 "${TMPDIR}/export" >/dev/null 2>&1
+}
+
+_stop_nbd_server_netlink() {
+	killall -SIGTERM nbd-server
+	rm -f "${TMPDIR}/export"
+}
+
+_netlink_connect() {
+	nbd-client localhost 8000 /dev/nbd0 >> "$FULL" 2>&1
+}
+
+_netlink_disconnect() {
+	nbd-client -d /dev/nbd0 >> "$FULL" 2>&1
+}
-- 
2.13.6