1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright 2023 Red Hat
4 */
5
6#ifndef UDS_VOLUME_H
7#define UDS_VOLUME_H
8
9#include <linux/atomic.h>
10#include <linux/cache.h>
11#include <linux/dm-bufio.h>
12#include <linux/limits.h>
13
14#include "permassert.h"
15#include "thread-utils.h"
16
17#include "chapter-index.h"
18#include "config.h"
19#include "geometry.h"
20#include "indexer.h"
21#include "index-layout.h"
22#include "index-page-map.h"
23#include "radix-sort.h"
24#include "sparse-cache.h"
25
26/*
27 * The volume manages deduplication records on permanent storage. The term "volume" can also refer
28 * to the region of permanent storage where the records (and the chapters containing them) are
29 * stored. The volume handles all I/O to this region by reading, caching, and writing chapter pages
30 * as necessary.
31 */
32
33enum index_lookup_mode {
34	/* Always do lookups in all chapters normally */
35	LOOKUP_NORMAL,
36	/* Only do a subset of lookups needed when rebuilding an index */
37	LOOKUP_FOR_REBUILD,
38};
39
40struct queued_read {
41	bool invalid;
42	bool reserved;
43	u32 physical_page;
44	struct uds_request *first_request;
45	struct uds_request *last_request;
46};
47
48struct __aligned(L1_CACHE_BYTES) search_pending_counter {
49	u64 atomic_value;
50};
51
52struct cached_page {
53	/* Whether this page is currently being read asynchronously */
54	bool read_pending;
55	/* The physical page stored in this cache entry */
56	u32 physical_page;
57	/* The value of the volume clock when this page was last used */
58	s64 last_used;
59	/* The cached page buffer */
60	struct dm_buffer *buffer;
61	/* The chapter index page, meaningless for record pages */
62	struct delta_index_page index_page;
63};
64
65struct page_cache {
66	/* The number of zones */
67	unsigned int zone_count;
68	/* The number of volume pages that can be cached */
69	u32 indexable_pages;
70	/* The maximum number of simultaneously cached pages */
71	u16 cache_slots;
72	/* An index for each physical page noting where it is in the cache */
73	u16 *index;
74	/* The array of cached pages */
75	struct cached_page *cache;
76	/* A counter for each zone tracking if a search is occurring there */
77	struct search_pending_counter *search_pending_counters;
78	/* The read queue entries as a circular array */
79	struct queued_read *read_queue;
80
81	/* All entries above this point are constant after initialization. */
82
83	/*
84	 * These values are all indexes into the array of read queue entries. New entries in the
85	 * read queue are enqueued at read_queue_last. To dequeue entries, a reader thread gets the
86	 * lock and then claims the entry pointed to by read_queue_next_read and increments that
87	 * value. After the read is completed, the reader thread calls release_read_queue_entry(),
88	 * which increments read_queue_first until it points to a pending read, or is equal to
89	 * read_queue_next_read. This means that if multiple reads are outstanding,
90	 * read_queue_first might not advance until the last of the reads finishes.
91	 */
92	u16 read_queue_first;
93	u16 read_queue_next_read;
94	u16 read_queue_last;
95
96	atomic64_t clock;
97};
98
99struct volume {
100	struct index_geometry *geometry;
101	struct dm_bufio_client *client;
102	u64 nonce;
103	size_t cache_size;
104
105	/* A single page worth of records, for sorting */
106	const struct uds_volume_record **record_pointers;
107	/* Sorter for sorting records within each page */
108	struct radix_sorter *radix_sorter;
109
110	struct sparse_cache *sparse_cache;
111	struct page_cache page_cache;
112	struct index_page_map *index_page_map;
113
114	struct mutex read_threads_mutex;
115	struct cond_var read_threads_cond;
116	struct cond_var read_threads_read_done_cond;
117	struct thread **reader_threads;
118	unsigned int read_thread_count;
119	bool read_threads_exiting;
120
121	enum index_lookup_mode lookup_mode;
122	unsigned int reserved_buffers;
123};
124
125int __must_check uds_make_volume(const struct uds_configuration *config,
126				 struct index_layout *layout,
127				 struct volume **new_volume);
128
129void uds_free_volume(struct volume *volume);
130
131int __must_check uds_replace_volume_storage(struct volume *volume,
132					    struct index_layout *layout,
133					    struct block_device *bdev);
134
135int __must_check uds_find_volume_chapter_boundaries(struct volume *volume,
136						    u64 *lowest_vcn, u64 *highest_vcn,
137						    bool *is_empty);
138
139int __must_check uds_search_volume_page_cache(struct volume *volume,
140					      struct uds_request *request,
141					      bool *found);
142
143int __must_check uds_search_volume_page_cache_for_rebuild(struct volume *volume,
144							  const struct uds_record_name *name,
145							  u64 virtual_chapter,
146							  bool *found);
147
148int __must_check uds_search_cached_record_page(struct volume *volume,
149					       struct uds_request *request, u32 chapter,
150					       u16 record_page_number, bool *found);
151
152void uds_forget_chapter(struct volume *volume, u64 chapter);
153
154int __must_check uds_write_chapter(struct volume *volume,
155				   struct open_chapter_index *chapter_index,
156				   const struct uds_volume_record records[]);
157
158void uds_prefetch_volume_chapter(const struct volume *volume, u32 chapter);
159
160int __must_check uds_read_chapter_index_from_volume(const struct volume *volume,
161						    u64 virtual_chapter,
162						    struct dm_buffer *volume_buffers[],
163						    struct delta_index_page index_pages[]);
164
165int __must_check uds_get_volume_record_page(struct volume *volume, u32 chapter,
166					    u32 page_number, u8 **data_ptr);
167
168int __must_check uds_get_volume_index_page(struct volume *volume, u32 chapter,
169					   u32 page_number,
170					   struct delta_index_page **page_ptr);
171
172#endif /* UDS_VOLUME_H */
173