1 files changed, 8 insertions, 64 deletions

diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index a38c2b24e..05424d875 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -552,65 +552,6 @@ ddt_get_pool_dedup_ratio(spa_t *spa)
 	return (dds_total.dds_ref_dsize * 100 / dds_total.dds_dsize);
 }
 
-int
-ddt_ditto_copies_needed(ddt_t *ddt, ddt_entry_t *dde, ddt_phys_t *ddp_willref)
-{
-	spa_t *spa = ddt->ddt_spa;
-	uint64_t total_refcnt = 0;
-	uint64_t ditto = spa->spa_dedup_ditto;
-	int total_copies = 0;
-	int desired_copies = 0;
-	int copies_needed = 0;
-
-	for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
-		ddt_phys_t *ddp = &dde->dde_phys[p];
-		zio_t *zio = dde->dde_lead_zio[p];
-		uint64_t refcnt = ddp->ddp_refcnt;	/* committed refs */
-		if (zio != NULL)
-			refcnt += zio->io_parent_count;	/* pending refs */
-		if (ddp == ddp_willref)
-			refcnt++;			/* caller's ref */
-		if (refcnt != 0) {
-			total_refcnt += refcnt;
-			total_copies += p;
-		}
-	}
-
-	if (ditto == 0 || ditto > UINT32_MAX)
-		ditto = UINT32_MAX;
-
-	if (total_refcnt >= 1)
-		desired_copies++;
-	if (total_refcnt >= ditto)
-		desired_copies++;
-	if (total_refcnt >= ditto * ditto)
-		desired_copies++;
-
-	copies_needed = MAX(desired_copies, total_copies) - total_copies;
-
-	/* encrypted blocks store their IV in DVA[2] */
-	if (DDK_GET_CRYPT(&dde->dde_key))
-		copies_needed = MIN(copies_needed, SPA_DVAS_PER_BP - 1);
-
-	return (copies_needed);
-}
-
-int
-ddt_ditto_copies_present(ddt_entry_t *dde)
-{
-	ddt_phys_t *ddp = &dde->dde_phys[DDT_PHYS_DITTO];
-	dva_t *dva = ddp->ddp_dva;
-	int copies = 0 - DVA_GET_GANG(dva);
-
-	for (int d = 0; d < DDE_GET_NDVAS(dde); d++, dva++)
-		if (DVA_IS_VALID(dva))
-			copies++;
-
-	ASSERT(copies >= 0 && copies < SPA_DVAS_PER_BP);
-
-	return (copies);
-}
-
 size_t
 ddt_compress(void *src, uchar_t *dst, size_t s_len, size_t d_len)
 {
@@ -1088,8 +1029,11 @@ ddt_sync_entry(ddt_t *ddt, ddt_entry_t *dde, dmu_tx_t *tx, uint64_t txg)
 			continue;
 		}
 		if (p == DDT_PHYS_DITTO) {
-			if (ddt_ditto_copies_needed(ddt, dde, NULL) == 0)
-				ddt_phys_free(ddt, ddk, ddp, txg);
+			/*
+			 * Note, we no longer create DDT-DITTO blocks, but we
+			 * don't want to leak any written by older software.
+			 */
+			ddt_phys_free(ddt, ddk, ddp, txg);
 			continue;
 		}
 		if (ddp->ddp_refcnt == 0)
@@ -1097,9 +1041,9 @@ ddt_sync_entry(ddt_t *ddt, ddt_entry_t *dde, dmu_tx_t *tx, uint64_t txg)
 		total_refcnt += ddp->ddp_refcnt;
 	}
 
-	if (dde->dde_phys[DDT_PHYS_DITTO].ddp_phys_birth != 0)
-		nclass = DDT_CLASS_DITTO;
-	else if (total_refcnt > 1)
+	/* We do not create new DDT-DITTO blocks. */
+	ASSERT0(dde->dde_phys[DDT_PHYS_DITTO].ddp_phys_birth);
+	if (total_refcnt > 1)
 		nclass = DDT_CLASS_DUPLICATE;
 	else
 		nclass = DDT_CLASS_UNIQUE;