1 files changed, 38 insertions, 104 deletions

diff --git a/libbcachefs/btree_update_leaf.c b/libbcachefs/btree_update_leaf.c
index bf7b1199..b42b83c5 100644
--- a/libbcachefs/btree_update_leaf.c
+++ b/libbcachefs/btree_update_leaf.c
@@ -1311,130 +1311,64 @@ static int need_whiteout_for_snapshot(struct btree_trans *trans,
 	return ret;
 }
 
-static int get_snapshot_overwrites(struct btree_trans *trans,
-				   enum btree_id btree,
-				   struct bpos pos,
-				   snapshot_id_list *overwrites)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	snapshot_id_list overwrites2;
-	u32 *i;
-	int ret = 0;
-
-	darray_init(overwrites);
-	darray_init(&overwrites2);
-
-	for_each_btree_key_norestart(trans, iter, btree,
-				     SPOS(pos.inode, pos.offset, 0),
-				     BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
-		if (bpos_ge(k.k->p, pos))
-			break;
-
-		if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, pos.snapshot)) {
-			ret = snapshot_list_add(c, &overwrites2, k.k->p.snapshot);
-			if (ret)
-				break;
-		}
-	}
-	bch2_trans_iter_exit(trans, &iter);
-
-	if (ret)
-		goto err;
-
-	darray_for_each(overwrites2, i)
-		if (!snapshot_list_has_ancestor(c, &overwrites2, *i)) {
-			ret = snapshot_list_add(c, overwrites, *i);
-			if (ret)
-				goto err;
-		}
-
-	*overwrites = overwrites2;
-out:
-	darray_exit(&overwrites2);
-	return ret;
-err:
-	darray_exit(overwrites);
-	goto out;
-}
-
 int __bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
-				   enum btree_id btree,
+				   enum btree_id id,
 				   struct bpos old_pos,
 				   struct bpos new_pos)
 {
 	struct bch_fs *c = trans->c;
-	snapshot_id_list old_overwrites, new_overwrites, updates;
-	bool began_transaction = false;
-	u32 *i;
+	struct btree_iter old_iter, new_iter;
+	struct bkey_s_c old_k, new_k;
+	snapshot_id_list s;
+	struct bkey_i *update;
 	int ret;
 
 	if (!bch2_snapshot_has_children(c, old_pos.snapshot))
 		return 0;
 
-	darray_init(&old_overwrites);
-	darray_init(&new_overwrites);
-	darray_init(&updates);
+	darray_init(&s);
 
-	ret =   get_snapshot_overwrites(trans, btree, old_pos, &old_overwrites) ?:
-		get_snapshot_overwrites(trans, btree, new_pos, &new_overwrites);
-	if (ret)
-		goto err;
-
-	darray_for_each(old_overwrites, i)
-		if (!snapshot_list_has_ancestor(c, &new_overwrites, *i)) {
-			ret = darray_push(&updates, *i);
-			if (ret)
-				goto err;
-		}
-
-	if (updates.nr > 4) {
-		bch2_trans_begin(trans);
-		began_transaction = true;
-	}
-
-	darray_for_each(updates, i) {
-		struct btree_iter iter;
-		struct bkey_i *update;
+	bch2_trans_iter_init(trans, &old_iter, id, old_pos,
+			     BTREE_ITER_NOT_EXTENTS|
+			     BTREE_ITER_ALL_SNAPSHOTS);
+	while ((old_k = bch2_btree_iter_prev(&old_iter)).k &&
+	       !(ret = bkey_err(old_k)) &&
+	       bkey_eq(old_pos, old_k.k->p)) {
+		struct bpos whiteout_pos =
+			SPOS(new_pos.inode, new_pos.offset, old_k.k->p.snapshot);;
+
+		if (!bch2_snapshot_is_ancestor(c, old_k.k->p.snapshot, old_pos.snapshot) ||
+		    snapshot_list_has_ancestor(c, &s, old_k.k->p.snapshot))
+			continue;
 
-		bch2_trans_iter_init(trans, &iter, btree,
-				     SPOS(new_pos.inode, new_pos.offset, *i),
-				     BTREE_ITER_NOT_EXTENTS|
-				     BTREE_ITER_INTENT);
-		update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
-		ret = PTR_ERR_OR_ZERO(update);
+		new_k = bch2_bkey_get_iter(trans, &new_iter, id, whiteout_pos,
+					   BTREE_ITER_NOT_EXTENTS|
+					   BTREE_ITER_INTENT);
+		ret = bkey_err(new_k);
 		if (ret)
 			break;
 
-		bkey_init(&update->k);
-		update->k.p		= iter.pos;
-		update->k.type		= KEY_TYPE_whiteout;
-
-		ret   = bch2_btree_iter_traverse(&iter) ?:
-			bch2_trans_update(trans, &iter, update,
-					  BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
-			(began_transaction && trans->nr_updates > 4
-			 ? bch2_trans_commit(trans, NULL, NULL, BTREE_INSERT_NOFAIL) : 0);
+		if (new_k.k->type == KEY_TYPE_deleted) {
+			update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
+			ret = PTR_ERR_OR_ZERO(update);
+			if (ret)
+				break;
 
-		bch2_trans_iter_exit(trans, &iter);
+			bkey_init(&update->k);
+			update->k.p		= whiteout_pos;
+			update->k.type		= KEY_TYPE_whiteout;
 
-		if (ret)
-			goto err;
-	}
+			ret = bch2_trans_update(trans, &new_iter, update,
+						BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		}
+		bch2_trans_iter_exit(trans, &new_iter);
 
-	if (began_transaction && trans->nr_updates) {
-		ret = bch2_trans_commit(trans, NULL, NULL, BTREE_INSERT_NOFAIL);
+		ret = snapshot_list_add(c, &s, old_k.k->p.snapshot);
 		if (ret)
-			goto err;
+			break;
 	}
-
-	if (began_transaction)
-		ret = -BCH_ERR_transaction_restart_nested;
-err:
-	darray_exit(&updates);
-	darray_exit(&new_overwrites);
-	darray_exit(&old_overwrites);
+	bch2_trans_iter_exit(trans, &old_iter);
+	darray_exit(&s);
 
 	return ret;
 }