[Exim] Exim 4.30 bug in handling large error files on Linux

Hi all,

I encountered a problem with Exim 4.30's handling of large error files on
Linux. I had Exim generating verbose logging information and managed to
fill exim_mainlog to 2^31 bytes.

At this point write() fails since Exim doesn't appear to open the mainlog
with O_LARGEFILE under Linux (a reasonable assumption). However, very
strange behaviour ensued.

Exim appear to stop receiving and delivering mail. I stopped Exim, moved
the file away and restarted. Email began to be delivered again but after a
period of about 10 minutes messages were being resent (multiple times).

I stopped Exim again, cleared out the retry and wait databases and
restarted. Everything behaved normal after this.

Has anyone else encountered this kind of problem? It seems to me that it
would be a simple bug to recreate (just fill up exim_mainlog).

Thanks,

Gavin