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

On Wed, 2020-08-05 at 09:45 +0200, Miklos Szeredi wrote:

On Wed, Aug 5, 2020 at 4:46 AM Ian Kent [off-list ref] wrote:

quoted

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
yes.

Maybe I just paranoid!
Ian