Subject: possible locking errors with imap-2000

From: Bernd Wagener <[email-masked]>
Date: Fri, 17 Nov 2000 11:36:37 +0100

Hello Mark!

I found a problem with imap-2000, perhaps with locking.
My environnement:
Linux - Server with newest sendmail and imap-2000.
Mailbox format is mbx and tmail is the local delivery agent.
I'm sure to have the newest tmail compiled with the c-lient library
from imap-2000.
The fact:
I started the system with the new imap and tmail and all was fine - but
only for 20 minutes, then the load of the mailserver was growing to very
high
values. I looked after it and found a lot of processes hanging in
disk-wait, both imapd and
tmail. I the log-file I found error-messages.
I decided to go back to the 4.7 version of imap.
Here are some lines from the log with error-messages:

/var/log/mail :
Oct 26 14:28:08 mailsrvd imapd[9404]: imap service init from
134.106.138.38
Oct 26 14:28:08 mailsrvd imapd[9404]: Authenticated user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:28:11 mailsrvd imapd[9407]: imap service init from
134.106.138.38
Oct 26 14:28:11 mailsrvd imapd[9407]: Authenticated user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:28:12 mailsrvd imapd[9409]: imap service init from
134.106.138.38
Oct 26 14:28:12 mailsrvd imapd[9409]: Authenticated user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:28:13 mailsrvd imapd[9411]: imap service init from
134.106.138.38
Oct 26 14:28:13 mailsrvd imapd[9411]: Authenticated user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38] 
Oct 26 14:29:22 mailsrvd imapd[9480]: imap service init from
134.106.138.38
Oct 26 14:29:22 mailsrvd imapd[9480]: Authenticated user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:29:43 mailsrvd imapd[9480]: Mailbox lock file /tmp/.815.ed0033
open failure: No
such file or directory
Oct 26 14:29:43 mailsrvd imapd[9480]: Logout user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:29:43 mailsrvd imapd[9409]: Mailbox lock file /tmp/.815.ed0033
open failure: No
such file or directory
Oct 26 14:29:43 mailsrvd imapd[9411]: Mailbox lock file /tmp/.815.ed0033
open failure: No
such file or directory
Oct 26 14:29:43 mailsrvd imapd[9407]: Mailbox lock file /tmp/.815.ed0033
open failure: No
such file or directory
Oct 26 14:29:43 mailsrvd imapd[9404]: Mailbox lock file /tmp/.815.ed0033
open failure: No
such file or directory
Oct 26 14:32:59 mailsrvd imapd[9407]: Logout user=7524420
host=cipfb818.hrz.uni-oldenburg.de [134.106.138.38]
Oct 26 14:33:09 mailsrvd imapd[9770]: imap service init from
134.106.63.71
Oct 26 14:33:09 mailsrvd imapd[9770]: Authenticated user=7104130
host=hrzsic10.hrz.uni-oldenburg.de [134.106.63.71]
Oct 26 14:33:49 mailsrvd tmail[9802]: delivering to 7104130+INBOX
Oct 26 14:33:49 mailsrvd tmail[9802]: Verifying safe delivery to
/folder/student/7104130/INBOX by UID 55605
Oct 26 14:33:49 mailsrvd tmail[9802]: mbx appending to #driver.mbx/INBOX
(file /folder/student/7104130/INBOX)
Oct 26 14:34:09 mailsrvd tmail[9813]: delivering to 7217870+INBOX
Oct 26 14:34:09 mailsrvd tmail[9813]: Verifying safe delivery to
/folder/student/7217870/INBOX by UID 32434
Oct 26 14:34:09 mailsrvd tmail[9813]: mbx appending to #driver.mbx/INBOX
(file /folder/student/7217870/INBOX)
Oct 26 14:34:09 mailsrvd tmail[9813]: delivered to
/folder/student/7217870/INBOX
Oct 26 14:34:09 mailsrvd tmail[9813]: Verifying safe delivery to
/folder/student/7217870/INBOX by UID 32434
Oct 26 14:34:09 mailsrvd tmail[9813]: all recipients delivered
Oct 26 14:34:21 mailsrvd tmail[9802]: Mailbox lock file /tmp/.815.dd8004
open failure: No
such file or directory
Oct 26 14:34:21 mailsrvd tmail[9802]: Unable to lock append mailbox
Oct 26 14:34:21 mailsrvd imapd[9770]: Mailbox lock file /tmp/.815.dd8004
open failure: No
such file or directory
Oct 26 14:34:21 mailsrvd tmail[9802]: message delivery failed to
/folder/student/7104130/INBOX Oct 26 14:51:29 mailsrvd tmail[10655]:
delivering to 6582030+INBOX
Oct 26 14:51:29 mailsrvd tmail[10655]: Verifying safe delivery to
/folder/student/6582030/INBOX by UID 32105
Oct 26 14:51:29 mailsrvd tmail[10655]: mbx appending to
#driver.mbx/INBOX (file /folder/student/6582030/INBOX)
Oct 26 14:51:29 mailsrvd tmail[10655]: Mailbox lock file
/tmp/.815.a98025 open failure: No such file or directory
Oct 26 14:51:29 mailsrvd tmail[10655]: Unable to lock append mailbox
Oct 26 14:51:29 mailsrvd tmail[10655]: message delivery failed to
/folder/student/6582030/INBOX
Oct 26 14:51:29 mailsrvd tmail[10655]: error in delivery

I found: imapd only erros, tmail only errors and some imapd and tmail
errors at the same time.

Any ideas?

Regards
Bernd
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From: Mark Crispin <[email-masked]>
Date: Fri, 17 Nov 2000 10:11:56 -0800 (PST)

On Fri, 17 Nov 2000 11:36:37 +0100, Bernd Wagener wrote:
> Mailbox lock file /tmp/.815.ed0033 open failure: No such file or directory

That's not "locking"; the routine is doing locking, but the failure is
something more basic: it couldn't open() the lock file on /tmp and the error
returned was ENOENT.

It looks as if, somehow, the /tmp directory became inaccessible.  What sort of
filesystem has /tmp on your system?

> I decided to go back to the 4.7 version of imap.

I doubt that that will make any difference at all, since the locking code is
identical between the 4.7 and 2000.  Going back to 4.7 will, however,
reintroduce bugs including security bugs on your system.

---

From: Bernd Wagener <[email-masked]>
Date: Mon, 20 Nov 2000 13:36:03 +0100

The filesystem /tmp is ext2. I send you only the lines of the log-file
with error-messages, during the same time a lot of mails are sent and
delivered 
successfully.

> reintroduce bugs including security bugs on your system.

Back with version 4.7 this error was not to see anymore.

Bernd

---

From: Mark Crispin <[email-masked]>
Date: Mon, 20 Nov 2000 09:35:38 -0800 (PST)

> with error-messages, during the same time a lot of mails are sent and

That indicates that the problem -- whatever it was -- was due to some external
condition and not c-client.  The error message means that c-client got an
ENOENT error in its attempt to create a zero-length file in /tmp.

Perhaps the filesystem holding /tmp filled up, but that would have caused a
different error than ENOENT.  You should probably check with the Linux
developers to find out what conditions could cause a create on /tmp to return
ENOENT.

> Back with version 4.7 this error was not to see anymore.

That is probably coincidental.  Nobody else has reported this problem.  There
must be something special on your system that caused it.