The way I understand it, it will only affect you if you use data=journal, and even then you only lose the last 30 seconds or so (before dismounting the fs at shutdown). The bug wasn't spotted earlier because almost noone uses data=journal as it slows the system down a lot and provides little gain.

So it is *very* unlikely that you're affected, and even less likely that you have lost anything. Do you often save important files within 30 seconds of shutting down?

It is not a serious worry.