[Devel] Re: [PATCH] Wake up mandatory locks waiter on chmod

[Trond Myklebust]

On Wed, 2007-09-19 at 14:07 -0400, J. Bruce Fields wrote:
> On Tue, Sep 18, 2007 at 10:36:32AM +0400, Pavel Emelyanov wrote:
> > J. Bruce Fields wrote:
> > > I would also prefer a locking scheme that didn't rely on the BKL.  That
> > > said, except for this race:
> > 
> > I would as well :) But I don't know the locking code good enough to
> > start fixing. Besides, even if I send a patch series that handles this,
> > I don't think that anyone will accept it, due to "this changes too much
> > code", "can you prove you fixed all the places" and so on...
> 
> Several people have expressed interest in a locking scheme for locks.c
> (and probably lockd) that doesn't depend on BKL, so I don't think it
> would be ignored.  But, yes, it would have to be done very carefully;
> there have been at least one or two previous attempts that failed.

Another long-term project might be to convert the current list of locks
into a more scalable structure: something like an rbtree might be more
appropriate for really large numbers of locks.

Cheers
  Trond