diff --git a/sys/sys/conf.h b/sys/sys/conf.h
index 214c8815dc64..8c1ee2516f87 100644
--- a/sys/sys/conf.h
+++ b/sys/sys/conf.h
@@ -94,7 +94,6 @@ struct cdev {
 			int __sid_bsize_phys; /* min physical block size */
 			int __sid_bsize_best; /* optimal block size */
 			struct snapdata *__sid_snapdata;
-			int (*__sid_copyonwrite)(struct vnode *, struct buf *);
 		} __si_disk;
 	} __si_u;
 	char		__si_namebuf[SPECNAMELEN + 1];
@@ -105,7 +104,6 @@ struct cdev {
 #define si_bsize_phys	__si_u.__si_disk.__sid_bsize_phys
 #define si_bsize_best	__si_u.__si_disk.__sid_bsize_best
 #define si_snapdata	__si_u.__si_disk.__sid_snapdata
-#define si_copyonwrite	__si_u.__si_disk.__sid_copyonwrite
 
 #ifdef _KERNEL
 
diff --git a/sys/ufs/ffs/ffs_extern.h b/sys/ufs/ffs/ffs_extern.h
index 336a264ff594..5c916e9187c8 100644
--- a/sys/ufs/ffs/ffs_extern.h
+++ b/sys/ufs/ffs/ffs_extern.h
@@ -47,7 +47,6 @@ struct ucred;
 struct vnode;
 struct vop_fsync_args;
 struct vop_reallocblks_args;
-struct vop_copyonwrite_args;
 
 int	ffs_alloc(struct inode *,
 	    ufs2_daddr_t, ufs2_daddr_t, int, struct ucred *, ufs2_daddr_t *);
@@ -62,6 +61,7 @@ ufs2_daddr_t ffs_blkpref_ufs2(struct inode *, ufs_lbn_t, int, ufs2_daddr_t *);
 int	ffs_checkfreefile(struct fs *, struct vnode *, ino_t);
 void	ffs_clrblock(struct fs *, u_char *, ufs1_daddr_t);
 void	ffs_clusteracct	(struct fs *, struct cg *, ufs1_daddr_t, int);
+int	ffs_copyonwrite(struct vnode *, struct buf *);
 vfs_fhtovp_t ffs_fhtovp;
 int	ffs_flushfiles(struct mount *, int, struct thread *);
 void	ffs_fragacct(struct fs *, int, int32_t [], int);
diff --git a/sys/ufs/ffs/ffs_snapshot.c b/sys/ufs/ffs/ffs_snapshot.c
index ac07e4b055db..7206eae570a0 100644
--- a/sys/ufs/ffs/ffs_snapshot.c
+++ b/sys/ufs/ffs/ffs_snapshot.c
@@ -100,7 +100,6 @@ static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
     struct fs *, ufs_lbn_t, int);
 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
     struct fs *, ufs_lbn_t, int);
-static int ffs_copyonwrite(struct vnode *, struct buf *);
 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t);
 
 /*
@@ -561,7 +560,6 @@ loop:
 	if (ip->i_nextsnap.tqe_prev != 0)
 		panic("ffs_snapshot: %d already on list", ip->i_number);
 	TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap);
-	devvp->v_rdev->si_copyonwrite = ffs_copyonwrite;
 	devvp->v_vflag |= VV_COPYONWRITE;
 	VI_UNLOCK(devvp);
 	ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp");
@@ -1451,7 +1449,6 @@ ffs_snapremove(vp)
 		if (TAILQ_FIRST(&sn->sn_head) != 0) {
 			VI_UNLOCK(devvp);
 		} else {
-			devvp->v_rdev->si_copyonwrite = 0;
 			snapblklist = sn->sn_blklist;
 			sn->sn_blklist = 0;
 			sn->sn_listsize = 0;
@@ -1893,7 +1890,6 @@ ffs_snapshot_mount(mp)
 	VOP_UNLOCK(vp, 0, td);
 	VI_LOCK(devvp);
 	ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount");
-	devvp->v_rdev->si_copyonwrite = ffs_copyonwrite;
 	sn->sn_listsize = snaplistsize;
 	sn->sn_blklist = (daddr_t *)snapblklist;
 	devvp->v_vflag |= VV_COPYONWRITE;
@@ -1933,7 +1929,6 @@ ffs_snapshot_unmount(mp)
 	lockdestroy(&sn->sn_lock);
 	free(sn, M_UFSMNT);
 	ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount");
-	devvp->v_rdev->si_copyonwrite = 0;
 	devvp->v_rdev->si_snapdata = NULL;
 	devvp->v_vflag &= ~VV_COPYONWRITE;
 	VI_UNLOCK(devvp);
@@ -1943,7 +1938,7 @@ ffs_snapshot_unmount(mp)
  * Check for need to copy block that is about to be written,
  * copying the block if necessary.
  */
-static int
+int
 ffs_copyonwrite(devvp, bp)
 	struct vnode *devvp;
 	struct buf *bp;
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 757de54ddc64..61fd28b3eac3 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -3433,8 +3433,8 @@ softdep_disk_prewrite(struct vnode *vp, struct buf *bp)
 		buf_start(bp);
 	mp_fixme("This should require the vnode lock.");
 	if ((vp->v_vflag & VV_COPYONWRITE) &&
-	    vp->v_rdev->si_copyonwrite &&
-	    (error = (*vp->v_rdev->si_copyonwrite)(vp, bp)) != 0 &&
+	    vp->v_rdev->si_snapdata != NULL &&
+	    (error = (ffs_copyonwrite)(vp, bp)) != 0 &&
 	    error != EOPNOTSUPP) {
 		bp->b_error = error;
 		bp->b_ioflags |= BIO_ERROR;