From 314464f422ec3e6917f30826ff358447fc1053cd Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Tue, 8 Jan 2008 04:45:24 +0000
Subject: [PATCH] Lock the vnode interlock while reading v_usecount to update
 si_usecount in a cdev in devfs_reclaim().

MFC after:	3 days
Reviewed by:	jeff (a while ago)
---
 sys/fs/devfs/devfs_vnops.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index 7c753f11fc7..6cae05e717a 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -992,17 +992,20 @@ devfs_reclaim(struct vop_reclaim_args *ap)
 
 	vnode_destroy_vobject(vp);
 
+	VI_LOCK(vp);
 	dev_lock();
 	dev = vp->v_rdev;
 	vp->v_rdev = NULL;
 
 	if (dev == NULL) {
 		dev_unlock();
+		VI_UNLOCK(vp);
 		return (0);
 	}
 
 	dev->si_usecount -= vp->v_usecount;
 	dev_unlock();
+	VI_UNLOCK(vp);
 	dev_rel(dev);
 	return (0);
 }