use the same pattern for in-memory and on-disk queues

openzfs · Aug 29, 2019 · 5bd8f78 · 5bd8f78
1 parent cb1d2b9
commit 5bd8f78
Showing 1 changed file with 23 additions and 5 deletions.
diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
@@ -2193,17 +2193,35 @@ dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
 	ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
 	ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
 
+	/*
+	 * Handle the in-memory scan queue.
+	 */
 	ds1_queued = scan_ds_queue_contains(scn, ds1->ds_object, &mintxg1);
 	ds2_queued = scan_ds_queue_contains(scn, ds2->ds_object, &mintxg2);
-	if (ds1_queued)
+
+	/* Sanity checking. */
+	if (ds1_queued) {
+		ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+		ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
+	}
+	if (ds2_queued) {
+		ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+		ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
+	}
+
+	if (ds1_queued && ds2_queued) {
+		/* Nothing to do if both are queued (or both are not queued). */
+	} else if (ds1_queued) {
 		scan_ds_queue_remove(scn, ds1->ds_object);
-	if (ds2_queued)
-		scan_ds_queue_remove(scn, ds2->ds_object);
-	if (ds1_queued)
 		scan_ds_queue_insert(scn, ds2->ds_object, mintxg1);
-	if (ds2_queued)
+	} else if (ds2_queued) {
+		scan_ds_queue_remove(scn, ds2->ds_object);
 		scan_ds_queue_insert(scn, ds1->ds_object, mintxg2);
+	}
 
+	/*
+	 * Handle the on-disk scan queue.
+	 */
 	ds1_queued = zap_lookup_int_key(dp->dp_meta_objset,
 	    scn->scn_phys.scn_queue_obj, ds1->ds_object, &mintxg1) == 0;
 	ds2_queued = zap_lookup_int_key(dp->dp_meta_objset,