43  * The buffered writer allows efficient I/O by buffering writes and committing page-sized segments
273 /* Create a buffered writer for an index region starting at offset. */
279 	struct buffered_writer *writer;  in uds_make_buffered_writer()  local
285 	result = vdo_allocate(1, struct buffered_writer, "buffered writer", &writer);  in uds_make_buffered_writer()
291 	*writer = (struct buffered_writer) {  in uds_make_buffered_writer()
303 	*writer_ptr = writer;  in uds_make_buffered_writer()
307 static size_t get_remaining_write_space(struct buffered_writer *writer)  in get_remaining_write_space()  argument
309 	return writer->start + UDS_BLOCK_SIZE - writer->end;  in get_remaining_write_space()
312 static int __must_check prepare_next_buffer(struct buffered_writer *writer)  in prepare_next_buffer()  argument
317 	if (writer->block_number >= writer->limit) {  in prepare_next_buffer()
318 		writer->error = UDS_OUT_OF_RANGE;  in prepare_next_buffer()
322 	data = dm_bufio_new(writer->client, writer->block_number, &buffer);  in prepare_next_buffer()
324 		writer->error = -PTR_ERR(data);  in prepare_next_buffer()
325 		return writer->error;  in prepare_next_buffer()
328 	writer->buffer = buffer;  in prepare_next_buffer()
329 	writer->start = data;  in prepare_next_buffer()
330 	writer->end = data;  in prepare_next_buffer()
334 static int flush_previous_buffer(struct buffered_writer *writer)  in flush_previous_buffer()  argument
338 	if (writer->buffer == NULL)  in flush_previous_buffer()
339 		return writer->error;  in flush_previous_buffer()
341 	if (writer->error == UDS_SUCCESS) {  in flush_previous_buffer()
342 		available = get_remaining_write_space(writer);  in flush_previous_buffer()
345 			memset(writer->end, 0, available);  in flush_previous_buffer()
347 		dm_bufio_mark_buffer_dirty(writer->buffer);  in flush_previous_buffer()
350 	dm_bufio_release(writer->buffer);  in flush_previous_buffer()
351 	writer->buffer = NULL;  in flush_previous_buffer()
352 	writer->start = NULL;  in flush_previous_buffer()
353 	writer->end = NULL;  in flush_previous_buffer()
354 	writer->block_number++;  in flush_previous_buffer()
355 	return writer->error;  in flush_previous_buffer()
358 void uds_free_buffered_writer(struct buffered_writer *writer)  in uds_free_buffered_writer()  argument
362 	if (writer == NULL)  in uds_free_buffered_writer()
365 	flush_previous_buffer(writer);  in uds_free_buffered_writer()
366 	result = -dm_bufio_write_dirty_buffers(writer->client);  in uds_free_buffered_writer()
370 	dm_bufio_client_destroy(writer->client);  in uds_free_buffered_writer()
371 	uds_put_io_factory(writer->factory);  in uds_free_buffered_writer()
372 	vdo_free(writer);  in uds_free_buffered_writer()
379 int uds_write_to_buffered_writer(struct buffered_writer *writer, const u8 *data,  in uds_write_to_buffered_writer()  argument
382 	int result = writer->error;  in uds_write_to_buffered_writer()
386 		if (writer->buffer == NULL) {  in uds_write_to_buffered_writer()
387 			result = prepare_next_buffer(writer);  in uds_write_to_buffered_writer()
391 		chunk_size = min(length, get_remaining_write_space(writer));  in uds_write_to_buffered_writer()
393 			memset(writer->end, 0, chunk_size);  in uds_write_to_buffered_writer()
395 			memcpy(writer->end, data, chunk_size);  in uds_write_to_buffered_writer()
400 		writer->end += chunk_size;  in uds_write_to_buffered_writer()
402 		if (get_remaining_write_space(writer) == 0)  in uds_write_to_buffered_writer()
403 			result = uds_flush_buffered_writer(writer);  in uds_write_to_buffered_writer()
409 int uds_flush_buffered_writer(struct buffered_writer *writer)  in uds_flush_buffered_writer()  argument
411 	if (writer->error != UDS_SUCCESS)  in uds_flush_buffered_writer()
412 		return writer->error;  in uds_flush_buffered_writer()
414 	return flush_previous_buffer(writer);  in uds_flush_buffered_writer()