What's an oplock_break?

Andrej Borsenkow borsenkow.msk at sni.de
Wed Oct 7 15:41:34 GMT 1998

> -----Original Message-----
> From: samba at samba.anu.edu.au [mailto:samba at 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?



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