[Linux-cluster] Re: GFS, what's remaining

[Alan Cox]

On Llu, 2005-09-05 at 12:53 -0700, Andrew Morton wrote:
> >  - How are they ref counted
> >  - What are the cleanup semantics
> >  - How do I pass a lock between processes (AF_UNIX sockets wont work now)
> >  - How do I poll on a lock coming free. 
> >  - What are the semantics of lock ownership
> >  - What rules apply for inheritance
> >  - How do I access a lock across threads.
> >  - What is the permission model. 
> >  - How do I attach audit to it
> >  - How do I write SELinux rules for it
> >  - How do I use mount to make namespaces appear in multiple vservers
> > 
> >  and thats for starters...
> 
> Return an fd from create_lockspace().

That only answers about four of the questions. The rest only come out if
create_lockspace behaves like a file system - in other words
create_lockspace is better known as either mkdir or mount.

Its certainly viable to make the lock/unlock functions taken a fd, it's
just not clear why the current lock/unlock functions we have won't do
the job. Being able to extend the functionality to leases later on may
be very powerful indeed and will fit the existing API