[dovecot] Re: quota

[Timo Sirainen]

On Tue, 2003-05-06 at 16:50, Sebastian Pachuta wrote:
> second, there is a problem when user exceed their quota

Yes, there's several problems. Biggest one is what to do if we can't
update dovecot-uidlist file.

If we continued normally but without storing the UIDs permanently, then
expunged some messages, logged out and logged in again, the UIDs are
different from last time and that breaks client's cache.

If we just overwrote next-UID field in dovecot-uidlist we'd get new UIDs
next time which is fine, except if client selects the mailbox multiple
times it gets different UIDs for the messages. That probably breaks some
clients (OE I think).

One kludgy solution is to overwrite next-UID field only when messages
are expunged and then force all clients that have selected the mailbox
to log out.

Overwriting next-UID isn't too safe either since readers don't do any
kind of locking for the file, but I'd hope writing 1-10 bytes is usually
atomic? Well, we could use fcntl() locking in out-of-diskspace
conditions but I'm not sure if it's worth it..