Re: [Gnu-arch-users] [BUG] FEATURE PLANS: revlib locking

[Andrew Suffield]

On Sat, May 29, 2004 at 08:55:28AM -0400, Aaron Bentley wrote:
> Andrew Suffield wrote:
> >NFS locking is somewhere between insanely complicated and completely
> >stupid. There are many approaches, all of which suck. fcntl() is the
> >only halfway reliable one, and if the server doesn't support it, it'll
> >just fail to lock. Lots of NFS servers don't support it.
> 
> >SMB locking is incompatible with everything else on the planet. Just
> >don't go there.
> 
> Thanks, Andrew.  Given that people want to be able to access revlibs 
> over NFS (Hi Miles!), I think it would make sense to have an 
> invented-here locking mechanism that would definitely work on NFS, and 
> maybe even SMB.

Not gonna happen. There does not exist a method by which you can
reliably acquire a lock without prior knowledge of the system or
arbitrarily restricting the set of supported systems.

People have been bashing their heads against this for the better part
of 20 years, and there just isn't a good answer. NFS and SMB suck
goats.

Now, if you just wanted linux-to-linux with the 2.4-or-later kernel
nfs server and client, fcntl() would just work without any apparent
trouble. But if you want to support almost any other combinations of
anything then you're screwed.

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
 : :' :  http://www.debian.org/ |
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