/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright 2023 Red Hat */ #ifndef UDS_SPARSE_CACHE_H #define UDS_SPARSE_CACHE_H #include "geometry.h" #include "indexer.h" /* * The sparse cache is a cache of entire chapter indexes from sparse chapters used for searching * for names after all other search paths have failed. It contains only complete chapter indexes; * record pages from sparse chapters and single index pages used for resolving hooks are kept in * the regular page cache in the volume. * * The most important property of this cache is the absence of synchronization for read operations. * Safe concurrent access to the cache by the zone threads is controlled by the triage queue and * the barrier requests it issues to the zone queues. The set of cached chapters does not and must * not change between the carefully coordinated calls to uds_update_sparse_cache() from the zone * threads. Outside of updates, every zone will get the same result when calling * uds_sparse_cache_contains() as every other zone. */ struct index_zone; struct sparse_cache; int __must_check uds_make_sparse_cache(const struct index_geometry *geometry, unsigned int capacity, unsigned int zone_count, struct sparse_cache **cache_ptr); void uds_free_sparse_cache(struct sparse_cache *cache); bool uds_sparse_cache_contains(struct sparse_cache *cache, u64 virtual_chapter, unsigned int zone_number); int __must_check uds_update_sparse_cache(struct index_zone *zone, u64 virtual_chapter); void uds_invalidate_sparse_cache(struct sparse_cache *cache); int __must_check uds_search_sparse_cache(struct index_zone *zone, const struct uds_record_name *name, u64 *virtual_chapter_ptr, u16 *record_page_ptr); #endif /* UDS_SPARSE_CACHE_H */