OPLOCK and locking problems: (Resource deadlock avoided)

[Andrew Bartlett]

On Fri, 2003-03-28 at 07:34, jra at dp.samba.org wrote:
> On Sun, Mar 23, 2003 at 02:23:45PM +1100, Andrew Bartlett wrote:
> > Earlier this week, I had a serious meltdown of Samba HEAD at my site. 
> > (A < 100 concurrent user, domain logon and homedir setup).
> > 
> > All the users share a single mandatory profile, which they think they
> > can write two, but can't.  (due to file permissions).  They think they
> > can due to the use of 'vfs_fake_perms.so'.  In any case, no matter what
> > the client thinks, I'm told this should not happen:
> > 
> > I've attached the first 6 mins on the log, but by the time it got to 11
> > AM I'm told it got impossible to use the system.  As smbds got caught up
> > in waiting for oplocks, I think the clients decided to reconnect.  This
> > created even more load, and by 12PM when I got onto the system, there
> > were way more smbd processes than machines to account for them.
> > 
> > The load at 12PM was 20, and just logging into the system with SSH took
> > *ages*.
> > 
> > Unfortunately I was unable to get an strace or gdb the culprit, as I had
> > to get the system back up and going again.
> > 
> > There is a slight possibility of tdb corruption (I should have removed
> > the locking tdb after the last crash), but no segfaulting processes. 
> > (This has occurred before, but I had blamed that).
> > 
> > By the end of the logfile, we have multiple smbds all sending oplock
> > replies to processes that don't expect them, connections being reset and
> > all hell breaking loose...
> > 
> > Personally, I suspect a tdb bug as the root cause, but our UDP based
> > oplock handling can't get off the hook either.
> 
> Are you running the Solaris kernel scalabel-fcntl patch ? If not,
> that was your problem, not the Samba code.

Nope, RedHat 8, kernel 2.4.18.

Andrew Bartlett

-- 
Andrew Bartlett                                 abartlet at pcug.org.au
Manager, Authentication Subsystems, Samba Team  abartlet at samba.org
Student Network Administrator, Hawker College   abartlet at hawkerc.net
http://samba.org     http://build.samba.org     http://hawkerc.net
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