Re: [PATCH 10/18] fsinfo: Provide notification overrun handling support [ver #21]

From: Ian Kent
Date: Wed Aug 05 2020 - 16:14:10 EST

On Wed, 2020-08-05 at 09:45 +0200, Miklos Szeredi wrote:
> On Wed, Aug 5, 2020 at 4:46 AM Ian Kent <raven@xxxxxxxxxx> wrote:
> > Coming back to an actual use case.
> >
> > What I said above is one aspect but, since I'm looking at this
> > right
> > now with systemd, and I do have the legacy code to fall back to,
> > the
> > "just reset everything" suggestion does make sense.
> >
> > But I'm struggling to see how I can identify notification buffer
> > overrun in libmount, and overrun is just one possibility for lost
> > notifications, so I like the idea that, as a library user, I can
> > work out that I need to take action based on what I have in the
> > notifications themselves.
> Hmm, what's the other possibility for lost notifications?

In user space that is:

Multi-threaded application races, single threaded applications and
signal processing races, other bugs ...

For example systemd has it's own event handling sub-system and handles
half a dozen or so event types of which the mount changes are one. It's
fairly complex so I find myself wondering if I can trust it and
wondering if there are undiscovered bugs in it. The answer to the
former is probably yes but the answer to the later is also probably

Maybe I just paranoid!