dovecot - Apr 2009 - overnight clients causing lockfiles to be converted to root-owned messages on debian lenny

Greetings all,

After running for more than a year without issue on debian lenny while
it was in the testing- we're now experiencing problems under
Lenny/Stable.

Dovecot now converts some sort of lockfile into messages, and they're
owned by root.  The result is a mess; clients can't read their
mailboxes with the root-owned files, and when the file is changed to
be owned by them, many mail clients don't like the zero-length message
(Outlook being one major client with this "problem".)

This happens to users who leave their email clients open overnight.  I
haven't found a cronjob that could be responsible for this.

Further details- 64 bit machine, we use maildir, /var/spool/mail is on
an xfs volume, and we run postfix, procmail, and spamassassin.
Dovecot version is 1.0.15; the machine is fully up-to-date with Debian
Stable (Lenny.)

Sample log entry of the aftermath; please pardon the sanitizing (host/username):

Apr 22 00:08:34 host dovecot: IMAP(user): Fixed a duplicate:
1240289413.9181_0.host:2,S.lock -> 1240373314.P6717Q0M159857.host
Apr 22 00:08:34 host dovecot: IMAP(user): Fixed a duplicate:
1240356531.15928_0.host:2,S.lock -> 1240373314.P9995Q3.host
Apr 22 00:08:34 host dovecot: IMAP(user):
open(/var/spool/mail/user/Maildir/cur/1240373314.P6717Q0M159857.host:2,)
failed: Permission denied

Brett

On Wed, 2009-04-22 at 15:23 -0400, Brett Dikeman wrote:
> Apr 22 00:08:34 host dovecot: IMAP(user): Fixed a duplicate:
> 1240289413.9181_0.host:2,S.lock -> 1240373314.P6717Q0M159857.host
Something's very wrong if .lock files are created to Maildir mail files.
It looks as if the Maildir is somehow being used as a mbox or something
else is very weird. Try to figure out what is creating those .lock
files..

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On Wed, Apr 22, 2009 at 3:38 PM, Timo Sirainen <tss at iki.fi>
wrote:
> On Wed, 2009-04-22 at 15:23 -0400, Brett Dikeman wrote:
>> Apr 22 00:08:34 host dovecot: IMAP(user): Fixed a duplicate:
>> 1240289413.9181_0.host:2,S.lock -> 1240373314.P6717Q0M159857.host
>
> Something's very wrong if .lock files are created to Maildir mail
files.
> It looks as if the Maildir is somehow being used as a mbox or something
> else is very weird. Try to figure out what is creating those .lock
> files..
The only things we have that touch mail on that system are dovecot and
procmail.  We don't export /var/spool/mail, and this is a pretty
minimal debian system install.  Ie, no funky desktop indexing programs
or the like.

The users affected have no immediate commonalities- no common clients,
most are IMAP but 1-2 are POP, some were logged out after timeout
while others logged out properly, etc.

The lock files are one possible problem, but it is a HUGE problem that
Dovecot is converting them into root-owned zero-length emails!

Brett