+static int insert_test_overlapping_extent(struct bch_fs *c, u64 inum, u64 start, u32 len, u32 snapid)
+{
+ struct bkey_i_cookie k;
+ int ret;
+
+ bkey_cookie_init(&k.k_i);
+ k.k_i.k.p.inode = inum;
+ k.k_i.k.p.offset = start + len;
+ k.k_i.k.p.snapshot = snapid;
+ k.k_i.k.size = len;
+
+ ret = bch2_trans_do(c, NULL, NULL, 0,
+ bch2_btree_insert_nonextent(trans, BTREE_ID_extents, &k.k_i,
+ BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE));
+ bch_err_fn(c, ret);
+ return ret;
+}
+
+static int test_extent_create_overlapping(struct bch_fs *c, u64 inum)
+{
+ return insert_test_overlapping_extent(c, inum, 0, 16, U32_MAX - 2) ?: /* overwrite entire */
+ insert_test_overlapping_extent(c, inum, 2, 8, U32_MAX - 2) ?:
+ insert_test_overlapping_extent(c, inum, 4, 4, U32_MAX) ?:
+ insert_test_overlapping_extent(c, inum, 32, 8, U32_MAX - 2) ?: /* overwrite front/back */
+ insert_test_overlapping_extent(c, inum, 36, 8, U32_MAX) ?:
+ insert_test_overlapping_extent(c, inum, 60, 8, U32_MAX - 2) ?:
+ insert_test_overlapping_extent(c, inum, 64, 8, U32_MAX);
+}
+
+/* snapshot unit tests */
+
+/* Test skipping over keys in unrelated snapshots: */
+static int test_snapshot_filter(struct bch_fs *c, u32 snapid_lo, u32 snapid_hi)
+{
+ struct btree_trans *trans;
+ struct btree_iter iter;
+ struct bkey_s_c k;
+ struct bkey_i_cookie cookie;
+ int ret;
+
+ bkey_cookie_init(&cookie.k_i);
+ cookie.k.p.snapshot = snapid_hi;
+ ret = bch2_btree_insert(c, BTREE_ID_xattrs, &cookie.k_i, NULL, 0);
+ if (ret)
+ return ret;
+
+ trans = bch2_trans_get(c);
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_xattrs,
+ SPOS(0, 0, snapid_lo), 0);
+ lockrestart_do(trans, bkey_err(k = bch2_btree_iter_peek_upto(&iter, POS(0, U64_MAX))));
+
+ BUG_ON(k.k->p.snapshot != U32_MAX);
+
+ bch2_trans_iter_exit(trans, &iter);
+ bch2_trans_put(trans);
+ return ret;
+}
+
+static int test_snapshots(struct bch_fs *c, u64 nr)
+{
+ struct bkey_i_cookie cookie;
+ u32 snapids[2];
+ u32 snapid_subvols[2] = { 1, 1 };
+ int ret;
+
+ bkey_cookie_init(&cookie.k_i);
+ cookie.k.p.snapshot = U32_MAX;
+ ret = bch2_btree_insert(c, BTREE_ID_xattrs, &cookie.k_i, NULL, 0);
+ if (ret)
+ return ret;
+
+ ret = bch2_trans_do(c, NULL, NULL, 0,
+ bch2_snapshot_node_create(trans, U32_MAX,
+ snapids,
+ snapid_subvols,
+ 2));
+ if (ret)
+ return ret;
+
+ if (snapids[0] > snapids[1])
+ swap(snapids[0], snapids[1]);
+
+ ret = test_snapshot_filter(c, snapids[0], snapids[1]);
+ bch_err_msg(c, ret, "from test_snapshot_filter");
+ return ret;
+}
+