Comment # 78 on bug 1063638 from Frederic Crozat

(In reply to Ludwig Nussel from comment #76)
> The background timer does not know if the time is a convenient one for the
> user.
> How about for example running those btrfs tasks directly after installing
> updates, as part of what the desktop applet shows? That's something desktop
> users are expected to do regularly anyways and installing updates also
> degrades system performance.

I'm not so sure it would work:

right now, the quota bug (which is the most visible bug) is happening in btrfs
transaction. This means it causes ANY IO write to the same btrfs partition to
be blocked. If you happen to have /home in that, it will cause freeze of most
applications trying to write on the system (in my case, gnome-shell, or
evolution or irc client). Having a notification that balance is in effect will
not be helpful at all for that case, because either you will not see it or even
if you see it, the system will still be in a "frozen" state, with no possible
action on it

> In addition there could be eg some passive notification that tells the user
> that some cleanup tasks need to be done, in case the system detects the need
> for that. Firefox does something like that for example.

If we get to a point where the quota bug doesn't block any more btrfs
transaction, balancing shouldn't be a problem anymore (I hope). But it could
still be sensible to have a passive notification "system optimization in
progress" with some way to pause it, if needed.