20  * open chapter space. Records are assigned to zones based on their record name. Within each zone,
22  * record is stored in a hash table to help determine if a new record duplicates an existing one.
23  * If new metadata for an existing name arrives, the record is altered in place. The array of
24  * records is 1-based so that record number 0 can be used to indicate an unused hash slot.
28  * indexed by record number instead of by record name. The number of hash slots will always be a
33  * each zone are interleaved to attempt to preserve temporal locality and assigned to record pages.
34  * Empty or deleted records are replaced by copies of a valid record so that the record pages only
35  * contain valid records. The chapter then constructs a delta index which maps each record name to
36  * the record page on which that record can be found, which is split into index pages. These
42  * zones. In addition, depending on the distribution of record names, a new zone may have more
79 	result = vdo_allocate_cache_aligned(records_size(open_chapter), "record pages",  in uds_make_open_chapter()
102 	struct uds_volume_record *record;  in probe_chapter_slots()  local
113 		 * record and should terminate the search.  in probe_chapter_slots()
119 		 * If the name of the record referenced by the slot matches and has not been  in probe_chapter_slots()
122 		record = &open_chapter->records[record_number];  in probe_chapter_slots()
123 		if ((memcmp(&record->name, name, UDS_RECORD_NAME_SIZE) == 0) &&  in probe_chapter_slots()
152 /* Add a record to the open chapter zone and return the remaining space. */
159 	struct uds_volume_record *record;  in uds_put_open_chapter()  local
172 	record = &open_chapter->records[record_number];  in uds_put_open_chapter()
173 	record->name = *name;  in uds_put_open_chapter()
174 	record->data = *metadata;  in uds_put_open_chapter()
202 /* Map each record name to its record page number in the delta chapter index. */
219 	 * The record pages should not have any empty space, so find a record with which to fill  in fill_delta_chapter_index()
221 	 * last record in any filled zone is guaranteed to not have been deleted, so use one of  in fill_delta_chapter_index()
237 		struct uds_volume_record *record = &collated_records[records];  in fill_delta_chapter_index()  local
240 		/* The record arrays in the zones are 1-based. */  in fill_delta_chapter_index()
245 		/* Use the fill record in place of an unused record. */  in fill_delta_chapter_index()
248 			*record = *fill_record;  in fill_delta_chapter_index()
252 		*record = open_chapter->records[record_index];  in fill_delta_chapter_index()
253 		result = uds_put_open_chapter_index_record(index, &record->name,  in fill_delta_chapter_index()
296 	struct uds_volume_record *record;  in uds_save_open_chapter()  local
333 			record = &open_chapter->records[record_index];  in uds_save_open_chapter()
334 			result = uds_write_to_buffered_writer(writer, (u8 *) record,  in uds_save_open_chapter()
335 							      sizeof(*record));  in uds_save_open_chapter()
361 	struct uds_volume_record record;  in load_version20()  local
381 		result = uds_read_from_buffered_reader(reader, (u8 *) &record,  in load_version20()
382 						       sizeof(record));  in load_version20()
388 							 &record.name);  in load_version20()
395 			remaining = uds_put_open_chapter(open_chapter, &record.name,  in load_version20()
396 							 &record.data);  in load_version20()