Minor patches for builds against ancient platforms

[Joseph Tam]

"M. Balridge" <dovecot at r.paypc.com> writes:

> I assume it's a rarely seen issue because few Dovecot users compile the
> software in caves on computers powered by horse-pulled generator
> wheels.

I resemble that remark.

>> Warning: Transaction log file /home/luser/mail/.imap/INBOX/dovecot.index.log
>> was locked for 95 seconds (rotating while syncing)

Timo recently explained to me it's probably caused by slow I/O or
processing.  This explanation is consistent with my observation that
the users who get these messages have jumbo mailboxes.

> imap(luser): Error: fchown(/home/luser/mail/.subscriptions.lock,
> group=501(coregroup)) failed: Operation not permitted (egid=200(users), group
> based on /home/luser/mail - see http://wiki2.dovecot.org/Errors/ChgrpNoPerm)
>
> imap(luser): Error: file_dotlock_open() failed with subscription file
> /home/luser/mail/.subscriptions: Operation not permitted
>
> .subscriptions doesn't exist either as a file or a directory in the named
> directories.
>
> Is there a "filter" against dot-files being opened within the bowels of dovecot?

You can disable dotclock altogether, but I don't think this is what you
meant.  You can use locking method "dotlock_try" rather than "dotlock"
-- the former will ignore quota/permissions problems and plow on.
(It still logs it.)  You could also align luser's mail folder group with
with luser's GID, which is usually what I do.

Maybe locks are created even when files don't exist as there may
be a race condition where another process is creating/deleting it at
the same time.

Joseph Tam <jtam.home at gmail.com>