Index: head/sys/geom/concat/g_concat.c
===================================================================
--- head/sys/geom/concat/g_concat.c
+++ head/sys/geom/concat/g_concat.c
@@ -279,8 +279,11 @@
 	g_destroy_bio(bp);
 }
 
+/*
+ * Called for both BIO_FLUSH and BIO_SPEEDUP. Just pass the call down
+ */
 static void
-g_concat_flush(struct g_concat_softc *sc, struct bio *bp)
+g_concat_passdown(struct g_concat_softc *sc, struct bio *bp)
 {
 	struct bio_queue_head queue;
 	struct g_consumer *cp;
@@ -340,8 +343,9 @@
 	case BIO_WRITE:
 	case BIO_DELETE:
 		break;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
-		g_concat_flush(sc, bp);
+		g_concat_passdown(sc, bp);
 		return;
 	case BIO_GETATTR:
 		if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
Index: head/sys/geom/eli/g_eli.c
===================================================================
--- head/sys/geom/eli/g_eli.c
+++ head/sys/geom/eli/g_eli.c
@@ -429,6 +429,7 @@
 	case BIO_GETATTR:
 	case BIO_FLUSH:
 	case BIO_ZONE:
+	case BIO_SPEEDUP:
 		break;
 	case BIO_DELETE:
 		/*
@@ -468,6 +469,7 @@
 	case BIO_GETATTR:
 	case BIO_FLUSH:
 	case BIO_DELETE:
+	case BIO_SPEEDUP:
 	case BIO_ZONE:
 		if (bp->bio_cmd == BIO_GETATTR)
 			cbp->bio_done = g_eli_getattr_done;
Index: head/sys/geom/gate/g_gate.c
===================================================================
--- head/sys/geom/gate/g_gate.c
+++ head/sys/geom/gate/g_gate.c
@@ -285,6 +285,7 @@
 	case BIO_DELETE:
 	case BIO_WRITE:
 	case BIO_FLUSH:
+	case BIO_SPEEDUP:
 		/* XXX: Hack to allow read-only mounts. */
 		if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0) {
 			g_io_deliver(pbp, EPERM);
@@ -871,6 +872,7 @@
 		case BIO_READ:
 		case BIO_DELETE:
 		case BIO_FLUSH:
+		case BIO_SPEEDUP:
 			break;
 		case BIO_WRITE:
 			error = copyout(bp->bio_data, ggio->gctl_data,
@@ -935,6 +937,7 @@
 				case BIO_DELETE:
 				case BIO_WRITE:
 				case BIO_FLUSH:
+				case BIO_SPEEDUP:
 					break;
 				}
 			}
Index: head/sys/geom/geom_disk.c
===================================================================
--- head/sys/geom/geom_disk.c
+++ head/sys/geom/geom_disk.c
@@ -560,6 +560,17 @@
 		devstat_start_transaction_bio(dp->d_devstat, bp2);
 		dp->d_strategy(bp2);
 		break;
+	case BIO_SPEEDUP:
+		bp2 = g_clone_bio(bp);
+		if (bp2 == NULL) {
+			g_io_deliver(bp, ENOMEM);
+			return;
+		}
+		bp2->bio_done = g_disk_done;
+		bp2->bio_caller1 = sc;
+		bp2->bio_disk = dp;
+		dp->d_strategy(bp2);
+		break;
 	default:
 		error = EOPNOTSUPP;
 		break;
Index: head/sys/geom/geom_io.c
===================================================================
--- head/sys/geom/geom_io.c
+++ head/sys/geom/geom_io.c
@@ -407,6 +407,7 @@
 		break;
 	case BIO_WRITE:
 	case BIO_DELETE:
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		if (cp->acw == 0)
 			return (EPERM);
Index: head/sys/geom/geom_slice.c
===================================================================
--- head/sys/geom/geom_slice.c
+++ head/sys/geom/geom_slice.c
@@ -312,6 +312,7 @@
 			/* now, pass it on downwards... */
 		}
 		/* FALLTHROUGH */
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		bp2 = g_clone_bio(bp);
 		if (bp2 == NULL) {
Index: head/sys/geom/journal/g_journal.c
===================================================================
--- head/sys/geom/journal/g_journal.c
+++ head/sys/geom/journal/g_journal.c
@@ -746,6 +746,7 @@
 			return;
 		}
 		/* FALLTHROUGH */
+	case BIO_SPEEDUP:
 	case BIO_DELETE:
 	default:
 		g_io_deliver(bp, EOPNOTSUPP);
Index: head/sys/geom/linux_lvm/g_linux_lvm.c
===================================================================
--- head/sys/geom/linux_lvm/g_linux_lvm.c
+++ head/sys/geom/linux_lvm/g_linux_lvm.c
@@ -215,6 +215,10 @@
 	/* XXX BIO_GETATTR allowed? */
 		break;
 	default:
+		/*
+		 * BIO_SPEEDUP and BIO_FLUSH should pass through to all sg
+		 * elements, but aren't.
+		 */
 		g_io_deliver(bp, EOPNOTSUPP);
 		return;
 	}
Index: head/sys/geom/mirror/g_mirror.c
===================================================================
--- head/sys/geom/mirror/g_mirror.c
+++ head/sys/geom/mirror/g_mirror.c
@@ -925,7 +925,8 @@
     struct g_mirror_disk *disk, struct bio *bp)
 {
 
-	if (bp->bio_cmd == BIO_FLUSH && bp->bio_error == EOPNOTSUPP)
+	if ((bp->bio_cmd == BIO_FLUSH || bp->bio_cmd == BIO_SPEEDUP) &&
+	    bp->bio_error == EOPNOTSUPP)
 		return;
 
 	if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
@@ -988,6 +989,10 @@
 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_flush,
 		    bp->bio_error);
 		break;
+	case BIO_SPEEDUP:
+		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_speedup,
+		    bp->bio_error);
+		break;
 	}
 
 	pbp->bio_inbed++;
@@ -1018,6 +1023,7 @@
 		case BIO_DELETE:
 		case BIO_WRITE:
 		case BIO_FLUSH:
+		case BIO_SPEEDUP:
 			pbp->bio_inbed--;
 			pbp->bio_children--;
 			break;
@@ -1043,6 +1049,7 @@
 	case BIO_DELETE:
 	case BIO_WRITE:
 	case BIO_FLUSH:
+	case BIO_SPEEDUP:
 		if (pbp->bio_children == 0) {
 			/*
 			 * All requests failed.
@@ -1149,6 +1156,7 @@
 	case BIO_READ:
 	case BIO_WRITE:
 	case BIO_DELETE:
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		break;
 	case BIO_GETATTR:
@@ -1783,6 +1791,7 @@
 		 */
 		TAILQ_INSERT_TAIL(&sc->sc_inflight, bp, bio_queue);
 		return;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		TAILQ_INIT(&queue);
 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
Index: head/sys/geom/nop/g_nop.h
===================================================================
--- head/sys/geom/nop/g_nop.h
+++ head/sys/geom/nop/g_nop.h
@@ -71,6 +71,7 @@
 	uintmax_t		 sc_cmd0s;
 	uintmax_t		 sc_cmd1s;
 	uintmax_t		 sc_cmd2s;
+	uintmax_t		 sc_speedups;
 	uintmax_t		 sc_readbytes;
 	uintmax_t		 sc_wrotebytes;
 	char			*sc_physpath;
Index: head/sys/geom/nop/g_nop.c
===================================================================
--- head/sys/geom/nop/g_nop.c
+++ head/sys/geom/nop/g_nop.c
@@ -255,6 +255,9 @@
 	case BIO_FLUSH:
 		sc->sc_flushes++;
 		break;
+	case BIO_SPEEDUP:
+		sc->sc_speedups++;
+		break;
 	case BIO_CMD0:
 		sc->sc_cmd0s++;
 		break;
@@ -438,6 +441,7 @@
 	sc->sc_deletes = 0;
 	sc->sc_getattrs = 0;
 	sc->sc_flushes = 0;
+	sc->sc_speedups = 0;
 	sc->sc_cmd0s = 0;
 	sc->sc_cmd1s = 0;
 	sc->sc_cmd2s = 0;
@@ -908,6 +912,7 @@
 		sc->sc_deletes = 0;
 		sc->sc_getattrs = 0;
 		sc->sc_flushes = 0;
+		sc->sc_speedups = 0;
 		sc->sc_cmd0s = 0;
 		sc->sc_cmd1s = 0;
 		sc->sc_cmd2s = 0;
@@ -978,6 +983,7 @@
 	sbuf_printf(sb, "%s<Deletes>%ju</Deletes>\n", indent, sc->sc_deletes);
 	sbuf_printf(sb, "%s<Getattrs>%ju</Getattrs>\n", indent, sc->sc_getattrs);
 	sbuf_printf(sb, "%s<Flushes>%ju</Flushes>\n", indent, sc->sc_flushes);
+	sbuf_printf(sb, "%s<Speedups>%ju</Speedups>\n", indent, sc->sc_speedups);
 	sbuf_printf(sb, "%s<Cmd0s>%ju</Cmd0s>\n", indent, sc->sc_cmd0s);
 	sbuf_printf(sb, "%s<Cmd1s>%ju</Cmd1s>\n", indent, sc->sc_cmd1s);
 	sbuf_printf(sb, "%s<Cmd2s>%ju</Cmd2s>\n", indent, sc->sc_cmd2s);
Index: head/sys/geom/part/g_part.c
===================================================================
--- head/sys/geom/part/g_part.c
+++ head/sys/geom/part/g_part.c
@@ -2272,6 +2272,7 @@
 		bp2->bio_offset += entry->gpe_offset;
 		g_io_request(bp2, cp);
 		return;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		break;
 	case BIO_GETATTR:
Index: head/sys/geom/raid/g_raid.c
===================================================================
--- head/sys/geom/raid/g_raid.c
+++ head/sys/geom/raid/g_raid.c
@@ -1111,6 +1111,7 @@
 	case BIO_WRITE:
 	case BIO_DELETE:
 	case BIO_FLUSH:
+	case BIO_SPEEDUP:
 		break;
 	case BIO_GETATTR:
 		if (!strcmp(bp->bio_attribute, "GEOM::candelete"))
Index: head/sys/geom/raid/tr_concat.c
===================================================================
--- head/sys/geom/raid/tr_concat.c
+++ head/sys/geom/raid/tr_concat.c
@@ -224,7 +224,7 @@
 		g_raid_iodone(bp, EIO);
 		return;
 	}
-	if (bp->bio_cmd == BIO_FLUSH) {
+	if (bp->bio_cmd == BIO_FLUSH || bp->bio_cmd == BIO_SPEEDUP) {
 		g_raid_tr_flush_common(tr, bp);
 		return;
 	}
Index: head/sys/geom/raid/tr_raid0.c
===================================================================
--- head/sys/geom/raid/tr_raid0.c
+++ head/sys/geom/raid/tr_raid0.c
@@ -204,7 +204,7 @@
 		g_raid_iodone(bp, EIO);
 		return;
 	}
-	if (bp->bio_cmd == BIO_FLUSH) {
+	if (bp->bio_cmd == BIO_FLUSH || bp->bio_cmd == BIO_SPEEDUP) {
 		g_raid_tr_flush_common(tr, bp);
 		return;
 	}
Index: head/sys/geom/raid/tr_raid1.c
===================================================================
--- head/sys/geom/raid/tr_raid1.c
+++ head/sys/geom/raid/tr_raid1.c
@@ -641,6 +641,7 @@
 	case BIO_DELETE:
 		g_raid_tr_iostart_raid1_write(tr, bp);
 		break;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		g_raid_tr_flush_common(tr, bp);
 		break;
Index: head/sys/geom/raid/tr_raid1e.c
===================================================================
--- head/sys/geom/raid/tr_raid1e.c
+++ head/sys/geom/raid/tr_raid1e.c
@@ -869,6 +869,7 @@
 	case BIO_DELETE:
 		g_raid_tr_iostart_raid1e_write(tr, bp);
 		break;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		g_raid_tr_flush_common(tr, bp);
 		break;
Index: head/sys/geom/raid/tr_raid5.c
===================================================================
--- head/sys/geom/raid/tr_raid5.c
+++ head/sys/geom/raid/tr_raid5.c
@@ -357,6 +357,7 @@
 	case BIO_WRITE:
 	case BIO_DELETE:
 	case BIO_FLUSH:
+	case BIO_SPEEDUP:
 		g_raid_iodone(bp, ENODEV);
 		break;
 	default:
Index: head/sys/geom/raid3/g_raid3.c
===================================================================
--- head/sys/geom/raid3/g_raid3.c
+++ head/sys/geom/raid3/g_raid3.c
@@ -1446,6 +1446,7 @@
 	case BIO_WRITE:
 	case BIO_DELETE:
 		break;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
 		g_raid3_flush(sc, bp);
 		return;
Index: head/sys/geom/shsec/g_shsec.c
===================================================================
--- head/sys/geom/shsec/g_shsec.c
+++ head/sys/geom/shsec/g_shsec.c
@@ -316,6 +316,7 @@
 	case BIO_READ:
 	case BIO_WRITE:
 	case BIO_FLUSH:
+	case BIO_SPEEDUP:
 		/*
 		 * Only those requests are supported.
 		 */
Index: head/sys/geom/stripe/g_stripe.c
===================================================================
--- head/sys/geom/stripe/g_stripe.c
+++ head/sys/geom/stripe/g_stripe.c
@@ -535,7 +535,7 @@
 }
 
 static void
-g_stripe_flush(struct g_stripe_softc *sc, struct bio *bp)
+g_stripe_pushdown(struct g_stripe_softc *sc, struct bio *bp)
 {
 	struct bio_queue_head queue;
 	struct g_consumer *cp;
@@ -594,8 +594,9 @@
 	case BIO_WRITE:
 	case BIO_DELETE:
 		break;
+	case BIO_SPEEDUP:
 	case BIO_FLUSH:
-		g_stripe_flush(sc, bp);
+		g_stripe_pushdown(sc, bp);
 		return;
 	case BIO_GETATTR:
 		/* To which provider it should be delivered? */