[$] Filtering fanotify events with BPF

Linux systems can have large filesystems; trying to keep up with thestream offanotify 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 discussionon how to improve in-kernel filtering of fanotify events to a jointsession 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 fewdifferent approaches to efficiently filter filesystem events.