Re: [PATCH] AFS: Implement file locking

David Howells
2007-05-26T23:55:49Z

J. Bruce Fields <bfields@fieldses.org> wrote:

> > + if (!afs_lock_manager) {
> > + afs_lock_manager = create_singlethread_workqueue("kafs_lockd");
> > + if (!afs_lock_manager)
> > + return -ENOMEM;
> > + }
> > + return 0;
>
> Doesn't this need some locking?

Oops. Yes. It used to be inside the lock_kernel() section, but has since
escaped.

> Do you allow upgrades and downgrades? (Just curious.)

AFS does not, as far as I know. Upgrades are dangerous anyway as you can get
deadlock quite easily.

> > + /* if we've already got a readlock on the server and no waiting
> > + * writelocks, then we might be able to instantly grant another
>
> Is that comment correct? (You don't really test for "waiting
> writelocks", do you?)

Locally, yes. 'if (list_empty(&vnode->pending_locks))' covers it quite
handily. I can't do anything about checking the server.

David