Steps to reproduce:

Check that cache is not configured. Empty list.

1. lctl pcc list /mnt/lustre

#

Try to delete any cache

1. lctl pcc del /mnt/lustre /mnt/pccro/

1. echo $?

0

Try for any word

1. lctl pcc del /mnt/lustre abc

1. echo $?

0

This is not critical, but it is good to have proper return codes for scripting or control that this is expected.