Index: vfs_mount.c
===================================================================
--- vfs_mount.c	(revision 185942)
+++ vfs_mount.c	(working copy)
@@ -1200,6 +1200,7 @@
 
 	mtx_assert(&Giant, MA_OWNED);
 
+coverpath:
 	if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
 		mnt_gen_r = mp->mnt_gen;
 		VI_LOCK(coveredvp);
@@ -1240,6 +1241,8 @@
 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
 	error = 0;
 	if (mp->mnt_lockref) {
+		if (coveredvp)
+			VOP_UNLOCK(coveredvp, 0);
 		if ((flags & MNT_FORCE) == 0) {
 			mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_NOINSMNTQ |
 			    MNTK_UNMOUNTF);
@@ -1248,13 +1251,13 @@
 				wakeup(mp);
 			}
 			MNT_IUNLOCK(mp);
-			if (coveredvp)
-				VOP_UNLOCK(coveredvp, 0);
 			return (EBUSY);
 		}
 		mp->mnt_kern_flag |= MNTK_DRAINING;
 		error = msleep(&mp->mnt_lockref, MNT_MTX(mp), PVFS,
 		    "mount drain", 0);
+		if (coveredvp)
+			goto coverpath;
 	}
 	MNT_IUNLOCK(mp);
 	KASSERT(mp->mnt_lockref == 0,