reftable/stack: fsync "tables.list" during compaction

In 1df18a1 (reftable: honor core.fsync, 2024-01-23), we have added
code to fsync both newly written reftables as well as "tables.list" to
disk. But there are two code paths where "tables.list" is being written:

  - When appending a new table due to a normal ref update.

  - When compacting a range of tables during compaction.

We have only addressed the former code path, but do not yet sync the new
"tables.list" file in the latter. Fix this omission.

Note that we are not yet adding any tests. These tests will be added
once the "reftable" backend has been upstreamed.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

reftable/stack.c

@@ -1018,6 +1018,14 @@ static int stack_compact_range(struct reftable_stack *st, int first, int last,
 		unlink(new_table_path.buf);
 		goto done;
 	}
+
+	err = fsync_component(FSYNC_COMPONENT_REFERENCE, lock_file_fd);
+	if (err < 0) {
+		err = REFTABLE_IO_ERROR;
+		unlink(new_table_path.buf);
+		goto done;
+	}
+
 	err = close(lock_file_fd);
 	lock_file_fd = -1;
 	if (err < 0) {