From ebba1b25f9e8f4cf0dc003b348e0e4be388b72f6 Mon Sep 17 00:00:00 2001
From: Alan Cox <alc@FreeBSD.org>
Date: Thu, 1 May 2003 03:10:38 +0000
Subject: [PATCH] Lock accesses to the vm_object's ref_count and
 resident_page_count.

---
 sys/kern/vfs_subr.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index bd02030ebe2..ea958ac591b 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -829,11 +829,15 @@ vcanrecycle(struct vnode *vp, struct mount **vnmpp)
 	/*
 	 * Don't recycle if we still have cached pages.
 	 */
-	if (VOP_GETVOBJECT(vp, &object) == 0 &&
-	     (object->resident_page_count ||
-	      object->ref_count)) {
-		error = EBUSY;
-		goto done;
+	if (VOP_GETVOBJECT(vp, &object) == 0) {
+		VM_OBJECT_LOCK(object);
+		if (object->resident_page_count ||
+		    object->ref_count) {
+			VM_OBJECT_UNLOCK(object);
+			error = EBUSY;
+			goto done;
+		}
+		VM_OBJECT_UNLOCK(object);
 	}
 	if (LIST_FIRST(&vp->v_cache_src)) {
 		/*