Index: vfs_syscalls.c
===================================================================
RCS file: /data/fbsd-cvs/ncvs/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.151.2.18
diff -u -r1.151.2.18 vfs_syscalls.c
--- vfs_syscalls.c	4 Apr 2003 20:35:58 -0000	1.151.2.18
+++ vfs_syscalls.c	22 Nov 2003 23:02:29 -0000
@@ -754,6 +754,11 @@
 	count = 0;
 	simple_lock(&mountlist_slock);
 	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
+		if (p->p_prison != NULL &&
+		    p->p_fd->fd_jdir->v_mount == mp) {
+			nmp = TAILQ_NEXT(mp, mnt_list);
+			continue;
+		}
 		if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock, p)) {
 			nmp = TAILQ_NEXT(mp, mnt_list);
 			continue;