[LTP] [PATCH] controllers/cpuacct: Fix deleting directories errors

[Dai Shili]

To remove a directory hierarchy on a normal file system you can use rm command to
remove all files from each subdirectory and then remove the parent directories.
But a cgroup which doesn't have any children and is associated only with zombie processes
is considered empty and can not be removed by rm.
The following errors will be reported.

cpuacct 1 TINFO: removing created directories
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cgroup.procs': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpu.cfs_period_us': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpu.stat': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpuacct.usage_percpu_sys': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpu.shares': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpuacct.usage_percpu': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpuacct.stat': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/cpuacct.usage': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/subgroup_1/cgroup.procs': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/subgroup_1/cpu.cfs_period_us': Operation not permitted
rm: cannot remove '/sys/fs/cgroup/cpu,cpuacct/ltp_cpuacct/subgroup_1/cpu.stat': Operation not permitted
...

It's recommended to use rmdir command.

[1] http://blog.tinola.com/?e=21
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/cgroup-v2.rst#n237

Reviewed-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Signed-off-by: Dai Shili <daisl.fnst@fujitsu.com>
---
 testcases/kernel/controllers/cpuacct/cpuacct.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/controllers/cpuacct/cpuacct.sh b/testcases/kernel/controllers/cpuacct/cpuacct.sh
index 99258c2..f526d0f 100755
--- a/testcases/kernel/controllers/cpuacct/cpuacct.sh
+++ b/testcases/kernel/controllers/cpuacct/cpuacct.sh
@@ -122,7 +122,10 @@ cleanup()
 
 	if [ "$testpath" ]; then
 		tst_res TINFO "removing created directories"
-		rm -rf $testpath
+		if [ -d "$testpath/subgroup_1" ]; then
+			rmdir $testpath/subgroup_*
+		fi
+			rmdir $testpath
 	fi
 
 	if [ "$mounted" -ne 1 ]; then
-- 
1.8.3.1