On Tue, Mar 3, 2020 at 10:26 AM Miklos Szeredi [off-list ref] wrote:

On Tue, Mar 3, 2020 at 10:13 AM David Howells [off-list ref] wrote:

quoted

Miklos Szeredi [off-list ref] wrote:

quoted

I'm doing a patch.   Let's see how it fares in the face of all these
preconceptions.

Don't forget the efficiency criterion.  One reason for going with fsinfo(2) is
that scanning /proc/mounts when there are a lot of mounts in the system is
slow (not to mention the global lock that is held during the read).

BTW, I do feel that there's room for improvement in userspace code as
well.  Even quite big mount table could be scanned for *changes* very
efficiently.  l.e. cache previous contents of /proc/self/mountinfo and
compare with new contents, line-by-line.  Only need to parse the
changed/added/removed lines.

Also it would be pretty easy to throttle the number of updates so
systemd et al. wouldn't hog the system with unnecessary processing.

Thanks,
Miklos