[PATCH 1/2] blktests: add cgroup2 infrastructure

[Josef Bacik <josef@toxicpanda.com>]

In order to test io.latency and other cgroup related things we need some
supporting helpers to setup and tear down cgroup2.  This adds support
for checking that we can even configure cgroup2 things, set them up if
need be, and then add the cleanup stuff to the main cleanup function so
everything is always in a clean state.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 check     |  2 ++
 common/rc | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/check b/check
index ebd87c097e25..1c9dbc518fa1 100755
--- a/check
+++ b/check
@@ -294,6 +294,8 @@ _cleanup() {
 		done
 		unset RESTORE_CPUS_ONLINE
 	fi
+
+	_cleanup_cgroup2
 }
 
 _call_test() {
diff --git a/common/rc b/common/rc
index 8a892bcd5fde..a785f2329687 100644
--- a/common/rc
+++ b/common/rc
@@ -202,3 +202,51 @@ _test_dev_in_hotplug_slot() {
 _filter_xfs_io_error() {
 	sed -e 's/^\(.*\)64\(: .*$\)/\1\2/'
 }
+
+_cgroup2_base_dir()
+{
+	grep cgroup2 /proc/mounts | awk '{ print $2 }'
+}
+
+_cleanup_cgroup2()
+{
+	_dir=$(_cgroup2_base_dir)/blktests
+	[ -d "${_dir}" ] || return
+
+	for i in $(find ${_dir} -type d | tac)
+	do
+		rmdir $i
+	done
+}
+
+_have_cgroup2()
+{
+	if ! grep -q 'cgroup2' /proc/mounts; then
+		SKIP_REASON="This test requires cgroup2"
+		return 1
+	fi
+	return 0
+}
+
+_have_cgroup2_controller_file()
+{
+	_have_cgroup2 || return 1
+
+	_controller=$1
+	_file=$2
+	_dir=$(_cgroup2_base_dir)
+
+	if ! grep -q ${_controller} ${_dir}/cgroup.controllers; then
+		SKIP_REASON="No support for ${_controller} cgroup controller"
+		return 1
+	fi
+
+	mkdir ${_dir}/blktests
+	echo "+${_controller}" > ${_dir}/cgroup.subtree_control
+	if [ ! -f ${_dir}/blktests/${_file} ]; then
+		_cleanup_cgroup2
+		SKIP_REASON="Cgroup file ${_file} doesn't exist"
+		return 1
+	fi
+	return 0
+}
-- 
2.14.3