diskio / filesystem related deadlock on SMP 6.0-STABLE machine.

[Niki Denev]

Hello,

I'm experiencing some problems with a 6.0-STABLE machine,
cvsupped and rebuilt yesterday.
I'm not sure that the problem is related to this last update, because
this machine is not very loaded currently.

The machine is with dual opteron mb from Supermicro,
with two Opteron 244s and 4GB of DDR 400 ECC Registered memory,
integrated Adaptec U320 SCSI controller (forced to U160 mode),
and four Seagate 36G 10K rpm scsi drives.

The kernel config is generic SMP with enabled QUOTA support,
accounting_enable=YES in rc.conf
and the root fs is a software Raid-10 running two striped mirrors
using geom_mirror and geom_stripe with the help of a little /boot partition
for loading the kernel and the required modules.

Kernel conf, dmesg and loader.conf are available here :

http://www.totalterror.net/freebsd/srv/

Yesterday i was able to deadlock the machine two times, doing
exactly the same thing :
I was doing rsync from another machine to this one. I was syncing
one rather big imap(Maildir) folder, about 270K msgs(files),
and at the same time i was syncing this folder contents via the bincimap
imap server on a remote machine running Kmail.
Then i run a "du -sh" on the folder in question.....and all my shells to it
 stopped working... 
I was able to ping the machine and connect to listening ports, 
but without getting banners from the daemons. 
There was also zero HDD activity at this time.
Unfortunately i forgot to enter the debuger and get a trace...(but, will it
 show something meaningfull or just the keyboard interrupt handler?)

After reseting the machine booted and rebuilt it's secondary components on 
the both mirrors ( maybe this is normal? it seems it's happeing everytime the 
machine is uncleanly restarted)

This is a big problem for me because this machine will soon 
enter in production, and should be able to serve imap to a dozen of clients.
I know that 270K msg in single imap folder is stupid,
but our old imap server running FreeBSD 5.4-STABLE(quite old STABLE)
on AMD 1800+ with 2G of ram and 80G IDE disk has no problems with it,
except being very slow of course

I hope this info is enough, if not i will gladly provide more.

Any suggestions are welcome,
Thanks.

--niki