[$] Filtering fanotify events with BPF

Linux systems can have large filesystems; trying to keep up with the
stream of

fanotify filesystem-monitoring notifications for them can be a struggle.
Fanotify is one of a few ways to monitor accesses to filesystems provided by the kernel.
Song Liu led a discussion
on how to improve in-kernel filtering of fanotify events to a joint
session of the filesystem and BPF tracks at the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit. He wants to combine the best parts of a few
different approaches to efficiently filter filesystem events.