Re: Does mandatory locking need to be set when the file is locked?

[Mike Fedyk <mfedyk@matchmail.com>]

On Tue, Dec 16, 2003 at 04:48:49PM -0500, Trond Myklebust wrote:
> P? ty , 16/12/2003 klokka 15:33, skreiv Mike Fedyk:
> > Another problem, is that with standard network filesystems (read NFS < 4)
> > the suggestive locks aren't propagated unless you use lock files!
> 
> Huh? If by 'suggestive' locks you mean advisory locks, then the above is
> pure FUD.
> 

I stand corrected.

> The Linux NFS implementation has been stateful ever since 2.2.0, when
> Olaf added full support for POSIX byte-range locks for v2 and v3 over
> the standard NLM protocol.
> Nobody has yet used it in order to implement support for BSD locks, but
> that is at least partly because it would break with the "standard"
> behaviour that BSD locks and POSIX locks should not see each other
> (remember those "sendmail" bugs a couple of years ago?).

Oh, the joys of netatalk using flock, and samba using fcntl... :(

> All NFSv4 adds of value when it comes to locking is support for
> mandatory locking, and a faster, more robust protocol than NLM ever was.
> Otherwise the combination NFSv3 w/ NLM has been keeping most people's
> mailboxes safe for several years now...

I'm very happy to hear this.

Thanks