Major problems with Samba 1.9.18p1 (HPUX 9.05) with oplocks

Jeremy Allison jallison at
Tue Jan 20 19:38:13 GMT 1998

Panu Outinen wrote:
> Hi there!
> I'm having major problems with the new oplocks feature of Samba 1.9.18p1.
> After running about a day or more Samba processes seem to stop responding
> or programs say that they can't open files that do exist and have been
> opened succesfully before. And after these symptomps come along I've had to
> restart Samba manually. 
> ... lines deleted....
> I've currently disabled the oplock feature by the pressure of the database
> users. So I'm not currently running the smbd processes with oplock with
> higher debug level. So is anyone else out there having similar problems?

We've recently discovered that there is a deadlock condition
in the p1 code with respect to the oplocks that can cause
this behavior under load.

The problem comes when smbd(1) tries to break an oplock
that smbd(2) holds at the same time as smbd(2) tries to
break an oplock that smbd(1) holds.

This can also occur due to a 'ring' of oplock break requests,
but the basic problem is the same. It's fairly rare and
timing dependent, which is why it didn't show up in all the 
large scale testing we did before the 1.9.18 release. 1.9.18p1 fixed
one artifact of the bug but the generic fix is to kill the 

I'm currently coding up a fix for this (and have some
test sites who are willing to test it - although more
would be welcome) and once we have determined we have
a definate fix then we'll release 1.9.18p2.

In the meantime if you run into the problem just setting

oplocks = no

in the [global] section of the smb.conf will fix the
problem (although Samba will be slower).

Sorry for the problem, we're working on getting it
fixed asap.

Jeremy Allison,
Samba Team.

Buying an operating system without source is like buying
a self-assembly Space Shuttle with no instructions.

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