hammer does cache_lock

[Damian Lubosch <dl@xxxxxxxx>]

Hello!

I am using Hammer since it came out in the 2.0 release in a "prepare for
production" system.
I have a setup with the postfix mailserver, dovecot and dspam. The
user's mail-directories /home/mail/* are on my hammer-home-partition
(/home size ~ 150GB) At the moment about 70GB are used.

I prepared the subdirectory for the mail service using the master-slave pfs.

#hammer pfs-status /home/mail  gives:
/home/mail      PFS #3 {
    sync-beg-tid=0x0000000000000001
    sync-end-tid=0x000000034a1bea60
    shared-uuid=9c8aed31-59b9-11dd-abcc-0102b31f83bf
    unique-uuid=9c8aed7c-59b9-11dd-abcc-0102b31f83bf
    label=""
    operating as a MASTER
}

the home itself reports:
hammer pfs-status /home
/home   PFS #0 {
    sync-beg-tid=0x0000000000000000
    sync-end-tid=0x000000034a1bea60
    shared-uuid=dcc842aa-59b6-11dd-abcc-0102b31f83bf
    unique-uuid=dcc842aa-59b6-11dd-abcc-0102b31f83bf
    label="home"
    operating as a MASTER
}

(there is also a webroot in /home with PFS#1)

Ok, the problem is now, that (for the second  time) some files are
blocked, I get following messages in my logs:
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7b9d3c8 "group"
[diagnostic] cache_lock: blocked on 0xd7b9d3c8 "group"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"
[diagnostic] cache_lock: blocked on 0xd7cce058 "dovecot.index.log"

The email-account containing this file isn't usable anymore when this
file is locked. When I try to access e.g. the group file (from dspam) my
console freezes.

I prepared the /home/mail dir to be in master-slave-mode to be able
later to synchronize the emails in realtime with an upcoming backup
server. Is this setup undoable to a "normal" hammer directory?

Is it possible to release the lock? What could cause it? I think the
dovecot.index.log-file is appended quite often with every incoming email.

I let do the cronjob "15 2 * * * /sbin/hammer -c /var/run/home -t 300
reblock /home >/dev/null 2>&1" every night.

I rebuilt the (release)dfly kernel on September 3rd, as I read that
Matthew commited some bugfixes to the official release a few weeks ago.

So far only a reboot helped to release the lock.

Thanks for any help.
Damian