--- fs/nfsserver/nfs_nfsdsocket.c.sav	2012-07-08 20:32:37.000000000 -0400
+++ fs/nfsserver/nfs_nfsdsocket.c	2012-07-08 20:42:03.000000000 -0400
@@ -352,7 +352,7 @@ APPLESTATIC void
 nfsrvd_dorpc(struct nfsrv_descript *nd, int isdgram,
     NFSPROC_T *p)
 {
-	int error = 0, lktype;
+	int error = 0, gotref = 0, lktype;
 	vnode_t vp;
 	mount_t mp = NULL;
 	struct nfsrvfh fh;
@@ -378,6 +378,11 @@ nfsrvd_dorpc(struct nfsrv_descript *nd, 
 				nd->nd_repstat = NFSERR_GARBAGE;
 				goto out;
 			}
+			gotref = 1;
+			NFSLOCKV4ROOTMUTEX();
+			nfsv4_getref(&nfsv4rootfs_lock, NULL,
+			    NFSV4ROOTLOCKMUTEXPTR, NULL);
+			NFSUNLOCKV4ROOTMUTEX();
 			if (nd->nd_procnum == NFSPROC_READ ||
 			    nd->nd_procnum == NFSPROC_READDIR ||
 			    nd->nd_procnum == NFSPROC_READLINK ||
@@ -471,6 +476,11 @@ nfsrvd_dorpc(struct nfsrv_descript *nd, 
 		nd->nd_flag &= ~ND_SAVEREPLY;
 
 out:
+	if (gotref != 0) {
+		NFSLOCKV4ROOTMUTEX();
+		nfsv4_relref(&nfsv4rootfs_lock);
+		NFSUNLOCKV4ROOTMUTEX();
+	}
 	NFSEXITCODE2(0, nd);
 }