samba - Oct 1998 - What's an oplock_break?

I've been seeing these in my logs files ever since I upgraded to 1.9.18p10
and turned on oplock support for users' home directories:

--snip --
1998/10/07 10:05:44 oplock_break: receive_smb timed out after 30 seconds.
1998/10/07 10:05:44 oplock_break failed for file Start Menu/Open Office 
Document.lnk (fnum = 14, dev = 808446, inode = 45cb8).
1998/10/07 10:05:44 oplock_break: client failure in break - shutting down
this smbd.
--snip --

Is this something to be worried about?  What effects does this have on
client-side performance? Note that I have set keepalives = 30 in my
smb.conf file - could that be the cause?

Thanks in advance.


Rob Naccarato           "Civilized men are more discourteous than savages
Sys Admin               because they know they can be impolite without
Sheridan College        having their skulls split, as a general thing."
Oakville, Ont. Canada                      - Robert E. Howard

> -----Original Message-----
> From: samba@samba.anu.edu.au [mailto:samba@samba.anu.edu.au]On Behalf Of
> Rob Naccarato
> Sent: Wednesday, October 07, 1998 6:21 PM
> To: Multiple recipients of list
> Subject: What's an oplock_break?
>
>
>
> I've been seeing these in my logs files ever since I upgraded to
1.9.18p10
> and turned on oplock support for users' home directories:
>
> --snip --
> 1998/10/07 10:05:44 oplock_break: receive_smb timed out after 30 seconds.
> 1998/10/07 10:05:44 oplock_break failed for file Start Menu/Open Office
> Document.lnk (fnum = 14, dev = 808446, inode = 45cb8).
> 1998/10/07 10:05:44 oplock_break: client failure in break - shutting down
> this smbd.
> --snip --
>
Are you sure you are running 1.9.18p10? Notably, this was the problem,
triggered by WinNT 4.0 Workstation bug. Workaround was available somewhen
about 1.9.18p4.

The problem is, sometimes WinNT 4.0 Workstation tries to rename the file,
for which it holds oplock (locking request). SAMBA server tries to first to
notify this workstation, that file is already opened and it should release
the lock. Unfortunately, NT never answers ... SAMBA assumes, the client has
died, and closes connection.

It happens only on NT Workstaion - not on Server. The easy way to reproduce
it was (in Explorer) - New -> New Word Document -> tip something in and
say
"Exit" in Word -> answer "Yes" when asked if you want to
save changes. Word
"hangs". Or, yes, it was Word 97.
> Is this something to be worried about?
Yes. Most probably, you don't run the latest version. Recheck.

 What effects does this have on
> client-side performance?
Well, immediate effect is these nasty delays. After server died, client
normally reconnects and finishes operation. It may have some impact on
mutual locking between several tasks.
 Note that I have set keepalives = 30 in my
> smb.conf file - could that be the cause?
>
No.

/Andrej

I've had same problem with WIN95,NCR Unix and samba p10. I reported this a
few weeks ago to samba-bugs(PR#9517). I must downgrade to 1.9.18p7.

Ivan Kuncl
 
Andrej wrote...

You better send bug report to samba-bugs@samba.anu.edu.au The problem with
WinNT was hit by me at early alpha of 1.9.18; if I remember correctly, all
reports referred to NT as well. You seem to be the first one reporting it
for Win95.

For the time being, turn off oplocks if not absolutely needed.