- Assume that all lower filesystems now support proper locking. Assert

   that they set v->v_vnlock.  This is true for all filesystems in the
   tree.
 - Remove all uses of LK_THISLAYER.  If the lower layer is locked, the
   null layer is locked.  We only use vget() to get a reference now.
   null essentially does no locking.  This fixes LOOKUP_SHARED with
   nullfs.
 - Remove the special LK_DRAIN considerations, I do not believe this is
   needed now as LK_DRAIN doesn't destroy the lower vnode's lock, and
   it's hardly used anymore.
 - Add one well commented hack to prevent the lowervp from going away
   while we're in it's VOP_LOCK routine.  This can only happen if we're
   forcibly unmounted while some callers are waiting in the lock.  In
   this case the lowervp could be recycled after we drop our last ref
   in null_reclaim().  Prevent this with a vhold().

1 files changed, 0 insertions, 2 deletions

diff --git a/sys/fs/nullfs/null.h b/sys/fs/nullfs/null.h
index b6cc7e3..c8fc5de 100644
--- a/sys/fs/nullfs/null.h
+++ b/sys/fs/nullfs/null.h
@@ -47,8 +47,6 @@ struct null_node {
 	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
 	struct vnode	        *null_lowervp;	/* VREFed once */
 	struct vnode		*null_vnode;	/* Back pointer */
-	int			null_pending_locks;
-	int			null_drain_wakeup;
 };
 
 #define	MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))