From 9534a4a47238751d26b9766b4f4121b229bb6ec1 Mon Sep 17 00:00:00 2001
From: kib <kib@FreeBSD.org>
Date: Tue, 24 Feb 2015 01:46:43 +0000
Subject: MFC r278523: In mountd, silence a race with the parallel unmount.

---
 sys/kern/vfs_mount.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

(limited to 'sys/kern/vfs_mount.c')

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index b2b4969..09fa7ed 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -888,12 +888,18 @@ vfs_domount_update(
 
 	ASSERT_VOP_ELOCKED(vp, __func__);
 	KASSERT((fsflags & MNT_UPDATE) != 0, ("MNT_UPDATE should be here"));
+	mp = vp->v_mount;
 
 	if ((vp->v_vflag & VV_ROOT) == 0) {
+		if (vfs_copyopt(*optlist, "export", &export, sizeof(export))
+		    == 0)
+			error = EXDEV;
+		else
+			error = EINVAL;
 		vput(vp);
-		return (EINVAL);
+		return (error);
 	}
-	mp = vp->v_mount;
+
 	/*
 	 * We only allow the filesystem to be reloaded if it
 	 * is currently mounted read-only.
-- 
cgit v1.1