- struct btree_iter iter;
- struct bkey_i_snapshot *n;
- struct bkey_s_c k;
- unsigned i;
- int ret = 0;
-
- bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots,
- POS_MIN, BTREE_ITER_INTENT);
- k = bch2_btree_iter_peek(&iter);
- ret = bkey_err(k);
- if (ret)
- goto err;
-
- for (i = 0; i < nr_snapids; i++) {
- k = bch2_btree_iter_prev_slot(&iter);
- ret = bkey_err(k);
- if (ret)
- goto err;
-
- if (!k.k || !k.k->p.offset) {
- ret = -ENOSPC;
- goto err;
- }
-
- n = bch2_trans_kmalloc(trans, sizeof(*n));
- ret = PTR_ERR_OR_ZERO(n);
- if (ret)
- goto err;
-
- bkey_snapshot_init(&n->k_i);
- n->k.p = iter.pos;
- n->v.flags = 0;
- n->v.parent = cpu_to_le32(parent);
- n->v.subvol = cpu_to_le32(snapshot_subvols[i]);
- n->v.pad = 0;
- SET_BCH_SNAPSHOT_SUBVOL(&n->v, true);
-
- ret = bch2_trans_update(trans, &iter, &n->k_i, 0) ?:
- bch2_mark_snapshot(trans, bkey_s_c_null, bkey_i_to_s_c(&n->k_i), 0);
- if (ret)
- goto err;
-
- new_snapids[i] = iter.pos.offset;
- }
-
- if (parent) {
- bch2_btree_iter_set_pos(&iter, POS(0, parent));
- k = bch2_btree_iter_peek(&iter);
- ret = bkey_err(k);
- if (ret)
- goto err;
-
- if (k.k->type != KEY_TYPE_snapshot) {
- bch_err(trans->c, "snapshot %u not found", parent);
- ret = -ENOENT;
- goto err;
- }
-
- n = bch2_trans_kmalloc(trans, sizeof(*n));
- ret = PTR_ERR_OR_ZERO(n);
- if (ret)
- goto err;
-
- bkey_reassemble(&n->k_i, k);
-
- if (n->v.children[0] || n->v.children[1]) {
- bch_err(trans->c, "Trying to add child snapshot nodes to parent that already has children");
- ret = -EINVAL;
- goto err;
- }
-
- n->v.children[0] = cpu_to_le32(new_snapids[0]);
- n->v.children[1] = cpu_to_le32(new_snapids[1]);
- SET_BCH_SNAPSHOT_SUBVOL(&n->v, false);
- ret = bch2_trans_update(trans, &iter, &n->k_i, 0);
- if (ret)
- goto err;
- }
-err:
- bch2_trans_iter_exit(trans, &iter);
- return ret;