samba - Jan 2000 - byte locking bug?

I'm having trouble with file locking in DOS over Samba.  The trouble is
Samba seems to be translating my lock request to a different range.  
Samba server is a linux box running 2.0.5a and clients are win95 or win98.  
The win32 call that I'm making to lock the file is called LockFile.  We
use this regularly, and lock a byte just before the 2GB range.  

We attempt to put a lock on the byte 0x7ffffff0 from one of the clients,
however when we run a UNIX program that reveals where the lock was put on
the file it indicates that the lock was put at 0x3ffffff0.  This same
program works correctly with a number of win95 NFS clients against linux
and other UNIX's NFS servers.

Is this a bug or a feature?  I thought I read something about samba
translating lock requests from DOS due to UNIX using a signed bit for
locking, but I wasn't sure if that was related or not.  What I need is for
UNIX clients and DOS clients to be able to access this file at the same
time using this type of locking.

-- 
Jon Mitchell
Systems Engineer, Subject Wills and Company
jrm@swc.com

You wrote:
| I'm having trouble with file locking in DOS over Samba.  The trouble
is
| Samba seems to be translating my lock request to a different range.  
[...]
| We attempt to put a lock on the byte 0x7ffffff0 from one of the
clients,
| however when we run a UNIX program that reveals where the lock was
put on
| the file it indicates that the lock was put at 0x3ffffff0. 

	Yes, the lock requests are indeed being mapped, to avoid
	the last two bits of a 32-bit quantity.  This avoids
	some disfeatures of a number of Unix OSs.

	It's probably better to lock a byte that's within the file
	than use a lock past the end for an IPC mechanism. There
	was a dicussion the the tchnical list a few days ago about
	reworking the locks, so I'd be cautious about depending on
	anything past the end of the file: the implementation is,
	as always, free to change.

--dave
-- 
David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | and astonish the rest.        -- Mark Twain
Willowdale, Ontario   | //www.oreilly.com/catalog/samba/author.html
Work: (905) 415-2849 Home: (416) 223-8968 Email: davecb@canada.sun.com