Comment # 31 on bug 1169774 from Jiri Slaby

In upstream as:
commit 14ff6286309e2853aed50083c9a83328423fdd8c
Author: Jan Kara <jack@suse.cz>
Date:   Wed May 20 15:31:19 2020 +0200

    jbd2: avoid leaking transaction credits when unreserving handle