SAMBA & ISAM Databases

Christopher R. Hertel crh at
Wed Sep 15 18:10:50 GMT 2004

On Wed, Sep 15, 2004 at 10:21:55AM -0700, Richard Sharpe wrote:
> On Wed, 15 Sep 2004, Christopher R. Hertel wrote:
> Hmmm, there are several issues here, I think.

This is CIFS we're talking about.  :)

> Firstly, was the file being accessed from UNIX and attempting to use fcntl
> or etc advisory locking? Also, were these being mapped to CIFS byte-range
> locks via smbfs/cifsvfs?

According to Mr. Bartlett, smbfs doesn't do proper locking.  That's what
was being used.  Ouch.

> Secondly, it seems that there is need for a standard around the correct
> interaction between CIFS and UNIX locks.
> Steve French and I discussed this briefly at CIFS2004 but we have not
> taken it much further.

Perhaps as part of the Unix extensions?

> I do think that it will be worth writing an RFC on this topic. There has
> been some work by HP, but I do not think it addresses all the issues.

We have a site now running that might work for writing such a document.

> The issues that must be addressed include how do CIFS byte-range and
> share-mode locks interact with UNIX advisory locks and UNIX/NFS read and
> write operations as well as how do UNIX advisory locks interact with CIFS
> byte-range and share-mode locks as well as read and write operations etc.
> A helpful way to look at this, ISTM, is to separate locking out from IO
> operations.
> The spec should also point out those areas in which you can lose. Ie, if a
> Windows user has a lock on a file, and a UNIX app does not bother to use
> advisory locking before accessing the file, you can lose.

Sounds like you could hammer out a draft...  :)

Chris -)-----

"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team --     -)-----   Christopher R. Hertel
jCIFS Team --   -)-----   ubiqx development, uninq.
ubiqx Team --     -)-----   crh at
OnLineBook --    -)-----   crh at

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