Re: CVS commit: src

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

"J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost> wrote:
> > I have not had time to follow your VFS changes, but can you explain why
> > did you remove VOP_LOCK/VOP_UNLOCK in tmpfs_reclaim()?  It was added to
> > prevent from the racy access of tn_links.
> 
> Hopefully a vnode lock is needed to access tn_links -- otherwise the
> VOP_LOCK/UNLOCK in tmpfs_reclaim() didn't protect it ...

Yes, tn_links is modified with the vnode lock held.  Unlocked access in
VOP_RECLAIM() racing with the release of the last last reference, used to
cause crashes due to premature reclamation attempts.  Given that VOP_LOCK()
acquires the vnode node, can you explain why this "didn't protect it"?

> As this commit prevents other threads from obtaining a lock while
> VOP_RECLAIM() is running the protection should be the same as before.

You mean VOP_RECLAIM() is now called with the vnode lock held?  Can you
please add an assert in tmpfs_reclaim() which demonstrates that?

Thanks.

-- 
Mindaugas