Re: OpenAFS 1.8.7 on Linux systems running Crowdstrike falcon-sensor

The bad news is, override_creds isn't going to fix this, because
current->fs isn't part of the creds. It's still going to be null (h/t jhutz)
The less bad news is, I think this will only affect closing a deleted file.
Other operations should not trigger cache I/O after a flush. (exit_files,
which occurs before exit_fs, called flush and fput, but fput these days
doesn't do the work immediately, it punts it to task_work). So if we punt
the unlink of a sillyrenamed file to a kthread, we should be able to avoid
this problem.

But we may have other issues.
If crowdstrike is validating dentry_open against current->fs->root, it
might deny cache I/O done on behalf of a chroot'd (or namespaced) process.
We can't solve that without punting ALL cache I/O to a kthread.