On Sat, Jul 07, 2007 at 05:27:21PM +0300, Antti Kantee
wrote:
> On Sat Jul 07 2007 at 16:59:09 +0300, Antti Kantee
wrote:
> > With what you're suggesting, sounds easier that we
simply don't drain the
> > lock at all. Reference counting of vnodes,
VXLOCK, taking an exclusive
> > lock in vclean() etc. should take care of the
effects of LK_DRAIN?
> >
> > I still don't like it, though, but I think it's
the best of the bad
> > options we have.
>
> Yup, that appears pretty good per simple testing:
>
> Index: vfs_subr.c
>
============================================================
=======
> RCS file: /cvsroot/src/sys/kern/vfs_subr.c,v
> retrieving revision 1.288
> diff -p -u -r1.288 vfs_subr.c
> --- vfs_subr.c 5 Jun 2007 12:31:31 -0000 1.288
> +++ vfs_subr.c 7 Jul 2007 14:27:01 -0000
>  -1522,12 +1522,11 vclean(struct vnode *vp,
int flags, stru
>
> /*
> * Even if the count is zero, the VOP_INACTIVE
routine may still
> - * have the object locked while it cleans it out. The
VOP_LOCK
> - * ensures that the VOP_INACTIVE routine is done with
its work.
> - * For active vnodes, it ensures that no other
activity can
> + * have the object locked while it cleans it out.
For
> + * active vnodes, it ensures that no other activity
can
> * occur while the underlying object is being cleaned
out.
> */
> - VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK);
> + VOP_LOCK(vp, LK_EXCLUSIVE | LK_INTERLOCK);
>
> /*
> * Clean out any cached data associated with the
vnode.
Ok. How much testing did you do? I like this idea the best,
now.
> -1649,6 +1648,7 vclean(struct vnode *vp,
int flags, stru
> */
> vp->v_op = dead_vnodeop_p;
> vp->v_tag = VT_NON;
> + vp->v_vnlock = NULL;
> simple_lock(&vp->v_interlock);
> VN_KNOTE(vp, NOTE_REVOKE); /* FreeBSD has this in
vn_pollgone() */
> vp->v_flag &= ~(VXLOCK|VLOCKSWORK);
Do we really need this?
Take care,
Bill
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