From d354520ebc31948c1edfd55e0502c18ec8a986d3 Mon Sep 17 00:00:00 2001
From: Takanori Watanabe <takawata@FreeBSD.org>
Date: Sat, 2 Oct 2004 17:17:04 +0000
Subject: [PATCH] Fix a problem when you try to mount  a directory on another
 directory belongs to the same filesystem. In this problem, getcwd(3) will
 fail.

I found the problem two years ago and I have forgotten to merge.

http://docs.FreeBSD.org/cgi/mid.cgi?200202251435.XAA91094
---
 sys/fs/unionfs/union_vnops.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/fs/unionfs/union_vnops.c b/sys/fs/unionfs/union_vnops.c
index c8240e9973a..89673dff2cb 100644
--- a/sys/fs/unionfs/union_vnops.c
+++ b/sys/fs/unionfs/union_vnops.c
@@ -972,6 +972,8 @@ union_getattr(ap)
 		union_newsize(ap->a_vp, VNOVAL, vap->va_size);
 	}
 
+	ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
+
 	if ((vap != ap->a_vap) && (vap->va_type == VDIR))
 		ap->a_vap->va_nlink += vap->va_nlink;
 	return (0);