--- a/usr/src/uts/common/fs/zfs/dmu_objset.c	Tue Feb 20 17:28:27 2007 -0800
+++ b/usr/src/uts/common/fs/zfs/dmu_objset.c	Tue Feb 20 22:55:55 2007 -0800
@@ -744,6 +744,7 @@
 	zio_t *zio;
 	list_t *list;
 	dbuf_dirty_record_t *dr;
+	int zio_flags;
 
 	dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
 
@@ -758,6 +759,9 @@
 	zb.zb_object = 0;
 	zb.zb_level = -1;
 	zb.zb_blkid = 0;
+	zio_flags = ZIO_FLAG_MUSTSUCCEED;
+	if (dmu_ot[DMU_OT_OBJSET].ot_metadata || zb.zb_level != 0)
+		zio_flags |= ZIO_FLAG_METADATA;
 	if (BP_IS_OLDER(os->os_rootbp, tx->tx_txg))
 		dsl_dataset_block_kill(os->os_dsl_dataset,
 		    os->os_rootbp, pio, tx);
@@ -765,7 +769,7 @@
 	    os->os_md_compress,
 	    dmu_get_replication_level(os->os_spa, &zb, DMU_OT_OBJSET),
 	    tx->tx_txg, os->os_rootbp, os->os_phys_buf, ready, killer, os,
-	    ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
+	    ZIO_PRIORITY_ASYNC_WRITE, zio_flags, &zb);
 
 	/*
 	 * Sync meta-dnode - the parent IO for the sync is the root block