Index: sys/kern/vfs_mount.c
===================================================================
--- sys/kern/vfs_mount.c
+++ sys/kern/vfs_mount.c
@@ -1703,6 +1703,7 @@
 		vdrop(coveredvp);
 	}
 	vn_finished_write(mp);
+	vfs_rel(mp);
 }
 
 /*
@@ -2127,7 +2128,7 @@
 
 	vfs_op_enter(mp);
 
-	vn_start_write(NULL, &mp, V_WAIT | V_MNTREF);
+	vn_start_write(NULL, &mp, V_WAIT);
 	MNT_ILOCK(mp);
 	if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 ||
 	    (mp->mnt_flag & MNT_UPDATE) != 0 ||
@@ -2200,6 +2201,7 @@
 	vfs_deallocate_syncvnode(mp);
 	error = VFS_UNMOUNT(mp, flags);
 	vn_finished_write(mp);
+	vfs_rel(mp);
 	/*
 	 * If we failed to flush the dirty blocks for this mount point,
 	 * undo all the cdir/rdir and rootvnode changes we made above.
Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c
+++ sys/kern/vfs_vnops.c
@@ -1904,9 +1904,6 @@
 	struct mount *mp;
 	int error;
 
-	KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
-	    ("V_MNTREF requires mp"));
-
 	error = 0;
 	/*
 	 * If a vnode is provided, get and return the mount point that
@@ -1930,7 +1927,7 @@
 	 * refcount for the provided mountpoint too, in order to
 	 * emulate a vfs_ref().
 	 */
-	if (vp == NULL && (flags & V_MNTREF) == 0)
+	if (vp == NULL)
 		vfs_ref(mp);
 
 	return (vn_start_write_refed(mp, flags, false));
@@ -1949,9 +1946,6 @@
 	struct mount *mp;
 	int error;
 
-	KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
-	    ("V_MNTREF requires mp"));
-
  retry:
 	if (vp != NULL) {
 		if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
@@ -1976,7 +1970,7 @@
 	 * emulate a vfs_ref().
 	 */
 	MNT_ILOCK(mp);
-	if (vp == NULL && (flags & V_MNTREF) == 0)
+	if (vp == NULL)
 		MNT_REF(mp);
 	if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
 		mp->mnt_secondary_writes++;
Index: sys/sys/vnode.h
===================================================================
--- sys/sys/vnode.h
+++ sys/sys/vnode.h
@@ -431,7 +431,6 @@
 #define	V_WAIT		0x0001	/* vn_start_write: sleep for suspend */
 #define	V_NOWAIT	0x0002	/* vn_start_write: don't sleep for suspend */
 #define	V_XSLEEP	0x0004	/* vn_start_write: just return after sleep */
-#define	V_MNTREF	0x0010	/* vn_start_write: mp is already ref-ed */
 
 #define	VR_START_WRITE	0x0001	/* vfs_write_resume: start write atomically */
 #define	VR_NO_SUSPCLR	0x0002	/* vfs_write_resume: do not clear suspension */
Index: sys/ufs/ufs/ufs_vfsops.c
===================================================================
--- sys/ufs/ufs/ufs_vfsops.c
+++ sys/ufs/ufs/ufs_vfsops.c
@@ -121,11 +121,12 @@
 		vfs_ref(mp);
 		KASSERT(*mp_busy,
 		    ("%s called without busied mount", __func__));
-		vn_start_write(NULL, &mp, V_WAIT | V_MNTREF);
+		vn_start_write(NULL, &mp, V_WAIT);
 		vfs_unbusy(mp);
 		*mp_busy = false;
 		error = quotaoff(td, mp, type);
 		vn_finished_write(mp);
+		vfs_rel(mp);
 		break;
 
 	case Q_SETQUOTA32: