Re: VOP_*LOCK* cleanup proposal

[Juergen Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost>]

On Tue, Jun 22, 2010 at 03:24:33PM +0000, Eduardo Horvath wrote:
> On Tue, 22 Jun 2010, Juergen Hannken-Illjes wrote:
> 
> > The vnode lock operations still carry some arguments and semantics from
> > our old lockmgr(9).  I propose to clean them up as:
> > 
> > 1) VOP_LOCK(vp, flags): Limit the set of allowed flags to LK_EXCLUSIVE,
> >    LK_SHARED and LK_NOWAIT.  LK_INTERLOCK is no longer allowed as it
> >    makes no sense here.
> 
> Have you tested these changes with LFS to make sure you haven't added any 
> new deadlocks or hangs?

No, but I see no new deadlocks here:

- VOP_ISLOCKED() doesn't return LK_EXCLOTHER for a long time so any
  "VOP_ISLOCKED(vp) == LK_EXCLOTHER" already was dead code.

- Replacing this test with "vn_lock(... LK_NOWAIT ...)" cannot add a
  deadlock as it will not block.

- The test in lfs_flush_pchain() is only flagged as I don't understand
  the intention here.

-- 
Juergen Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)