diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index 47cb86b08..3e04793cf 100644
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -656,9 +656,16 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 		uint64_t end = (off + len) >> shift;
 		uint64_t i;
 
-		ASSERT(dn->dn_datablkshift != 0);
 		ASSERT(dn->dn_indblkshift != 0);
 
+		/*
+		 * dnode_reallocate() can result in an object with indirect
+		 * blocks having an odd data block size.  In this case,
+		 * just check the single block.
+		 */
+		if (dn->dn_datablkshift == 0)
+			start = end = 0;
+
 		zio = zio_root(tx->tx_pool->dp_spa,
 		    NULL, NULL, ZIO_FLAG_CANFAIL);
 		for (i = start; i <= end; i++) {