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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright 2023 Red Hat4 */5 6#ifndef UDS_SPARSE_CACHE_H7#define UDS_SPARSE_CACHE_H8 9#include "geometry.h"10#include "indexer.h"11 12/*13 * The sparse cache is a cache of entire chapter indexes from sparse chapters used for searching14 * for names after all other search paths have failed. It contains only complete chapter indexes;15 * record pages from sparse chapters and single index pages used for resolving hooks are kept in16 * the regular page cache in the volume.17 *18 * The most important property of this cache is the absence of synchronization for read operations.19 * Safe concurrent access to the cache by the zone threads is controlled by the triage queue and20 * the barrier requests it issues to the zone queues. The set of cached chapters does not and must21 * not change between the carefully coordinated calls to uds_update_sparse_cache() from the zone22 * threads. Outside of updates, every zone will get the same result when calling23 * uds_sparse_cache_contains() as every other zone.24 */25 26struct index_zone;27struct sparse_cache;28 29int __must_check uds_make_sparse_cache(const struct index_geometry *geometry,30 unsigned int capacity, unsigned int zone_count,31 struct sparse_cache **cache_ptr);32 33void uds_free_sparse_cache(struct sparse_cache *cache);34 35bool uds_sparse_cache_contains(struct sparse_cache *cache, u64 virtual_chapter,36 unsigned int zone_number);37 38int __must_check uds_update_sparse_cache(struct index_zone *zone, u64 virtual_chapter);39 40void uds_invalidate_sparse_cache(struct sparse_cache *cache);41 42int __must_check uds_search_sparse_cache(struct index_zone *zone,43 const struct uds_record_name *name,44 u64 *virtual_chapter_ptr, u16 *record_page_ptr);45 46#endif /* UDS_SPARSE_CACHE_H */47