On Mon, Sep 18, 2023 at 2:40 PM Jan Kara <jack@xxxxxxx> wrote: > Is there any problem with using fanotify for you? Turns out fanotify is unusable for me, unfortunately. I have been using inotify to get notifications of cgroup events, but the cgroup filesystem appears to be unsupported by fanotify: all attempts to use fanotify_mark() on cgroup event files fail with ENODEV. I think that comes from fanotify_test_fsid(). Filesystems without a fsid work just fine with inotify, but fail with fanotify. Since fanotify lacks important features, is it really a good idea to feature-freeze inotify? (By the way, what was not documented is that fanotify_init() can only be used by unprivileged processes if the FAN_REPORT_FID flag was specified. I had to read the kernel sources to figure that out - I have no idea why this limitation exists - the code comment in the kernel source doesn't explain it.)
