Mandatory Lock Support

Andy Bakun (
Wed, 10 Sep 1997 14:09:16 -0500

This appears in Documentation/ for 2.0.30:

> File locking is a system designed to prevent that several processes
> write to the same file at the same time, causing data
> corruption. Mandatory file locking is more secure than the usual
> algorithm and is used by some Unix System 5 style database
> applications. For details, read Documentation/mandatory.txt. To use
> this option safely you must have newer NFS daemons, new samba, new
> netatalk, new mars-nwe and other file servers. At the time of
> writing none of these are available. So it's safest to say N here
> unless you really know that you need this feature.

and Documentation/mandatory.txt:

> Mandatory File Locking For The Linux Operating System
> Andy Walker <>
> 15 April 1996
(the rest of the file gives nice usage and background info)

I think I've been reading these words since at least 1.2.something. When
was the time of this writing, 4/96? What is "newer"? Did mandatory
locking ever hit the mainstream and were "newer" file servers produced?
I'm using RedHat 4.2, which was built AFTER I first read this, so I'm
confident (altho not completely sure) that I have "newer" versions of the
above mentioned servers, although, no comparsion date for "newer" is
mentioned. Also, this is the first time I compiled a kernel on this
machine, installed the source from the redhat package, and
CONFIG_LOCK_MANDATORY defaulted to yes.