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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2008 Oracle. All rights reserved.
4 */
5
6#ifndef BTRFS_COMPRESSION_H
7#define BTRFS_COMPRESSION_H
8
9#include <linux/sizes.h>
10#include <linux/mm.h>
11#include <linux/list.h>
12#include <linux/workqueue.h>
13#include <linux/wait.h>
14#include <linux/pagemap.h>
15#include "bio.h"
16#include "messages.h"
17
18struct address_space;
19struct page;
20struct inode;
21struct btrfs_inode;
22struct btrfs_ordered_extent;
23struct btrfs_bio;
24
25/*
26 * We want to make sure that amount of RAM required to uncompress an extent is
27 * reasonable, so we limit the total size in ram of a compressed extent to
28 * 128k. This is a crucial number because it also controls how easily we can
29 * spread reads across cpus for decompression.
30 *
31 * We also want to make sure the amount of IO required to do a random read is
32 * reasonably small, so we limit the size of a compressed extent to 128k.
33 */
34
35/* Maximum length of compressed data stored on disk */
36#define BTRFS_MAX_COMPRESSED (SZ_128K)
37#define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
38static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
39
40/* Maximum size of data before compression */
41#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
42
43#define BTRFS_ZLIB_DEFAULT_LEVEL 3
44
45struct compressed_bio {
46 /* Number of compressed folios in the array. */
47 unsigned int nr_folios;
48
49 /* The folios with the compressed data on them. */
50 struct folio **compressed_folios;
51
52 /* starting offset in the inode for our pages */
53 u64 start;
54
55 /* Number of bytes in the inode we're working on */
56 unsigned int len;
57
58 /* Number of bytes on disk */
59 unsigned int compressed_len;
60
61 /* The compression algorithm for this bio */
62 u8 compress_type;
63
64 /* Whether this is a write for writeback. */
65 bool writeback;
66
67 union {
68 /* For reads, this is the bio we are copying the data into */
69 struct btrfs_bio *orig_bbio;
70 struct work_struct write_end_work;
71 };
72
73 /* Must be last. */
74 struct btrfs_bio bbio;
75};
76
77/* @range_end must be exclusive. */
78static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u64 cur)
79{
80 const u64 folio_end = folio_pos(folio) + folio_size(folio);
81
82 /* @cur must be inside the folio. */
83 ASSERT(folio_pos(folio) <= cur);
84 ASSERT(cur < folio_end);
85 return min(range_end, folio_end) - cur;
86}
87
88int __init btrfs_init_compress(void);
89void __cold btrfs_exit_compress(void);
90
91bool btrfs_compress_level_valid(unsigned int type, int level);
92int btrfs_compress_folios(unsigned int type, int level, struct address_space *mapping,
93 u64 start, struct folio **folios, unsigned long *out_folios,
94 unsigned long *total_in, unsigned long *total_out);
95int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
96 unsigned long start_byte, size_t srclen, size_t destlen);
97int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
98 struct compressed_bio *cb, u32 decompressed);
99
100void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
101 struct folio **compressed_folios,
102 unsigned int nr_folios, blk_opf_t write_flags,
103 bool writeback);
104void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
105
106int btrfs_compress_str2level(unsigned int type, const char *str);
107
108struct folio *btrfs_alloc_compr_folio(void);
109void btrfs_free_compr_folio(struct folio *folio);
110
111enum btrfs_compression_type {
112 BTRFS_COMPRESS_NONE = 0,
113 BTRFS_COMPRESS_ZLIB = 1,
114 BTRFS_COMPRESS_LZO = 2,
115 BTRFS_COMPRESS_ZSTD = 3,
116 BTRFS_NR_COMPRESS_TYPES = 4,
117};
118
119struct workspace_manager {
120 struct list_head idle_ws;
121 spinlock_t ws_lock;
122 /* Number of free workspaces */
123 int free_ws;
124 /* Total number of allocated workspaces */
125 atomic_t total_ws;
126 /* Waiters for a free workspace */
127 wait_queue_head_t ws_wait;
128};
129
130struct list_head *btrfs_get_workspace(int type, int level);
131void btrfs_put_workspace(int type, struct list_head *ws);
132
133struct btrfs_compress_op {
134 struct workspace_manager *workspace_manager;
135 /* Maximum level supported by the compression algorithm */
136 int min_level;
137 int max_level;
138 int default_level;
139};
140
141/* The heuristic workspaces are managed via the 0th workspace manager */
142#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
143
144extern const struct btrfs_compress_op btrfs_heuristic_compress;
145extern const struct btrfs_compress_op btrfs_zlib_compress;
146extern const struct btrfs_compress_op btrfs_lzo_compress;
147extern const struct btrfs_compress_op btrfs_zstd_compress;
148
149const char* btrfs_compress_type2str(enum btrfs_compression_type type);
150bool btrfs_compress_is_valid_type(const char *str, size_t len);
151
152int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
153
154int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
155 struct folio **in_folio_ret);
156
157int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
158 u64 start, struct folio **folios, unsigned long *out_folios,
159 unsigned long *total_in, unsigned long *total_out);
160int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
161int zlib_decompress(struct list_head *ws, const u8 *data_in,
162 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
163 size_t destlen);
164struct list_head *zlib_alloc_workspace(unsigned int level);
165void zlib_free_workspace(struct list_head *ws);
166struct list_head *zlib_get_workspace(unsigned int level);
167
168int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
169 u64 start, struct folio **folios, unsigned long *out_folios,
170 unsigned long *total_in, unsigned long *total_out);
171int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
172int lzo_decompress(struct list_head *ws, const u8 *data_in,
173 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
174 size_t destlen);
175struct list_head *lzo_alloc_workspace(void);
176void lzo_free_workspace(struct list_head *ws);
177
178int zstd_compress_folios(struct list_head *ws, struct address_space *mapping,
179 u64 start, struct folio **folios, unsigned long *out_folios,
180 unsigned long *total_in, unsigned long *total_out);
181int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
182int zstd_decompress(struct list_head *ws, const u8 *data_in,
183 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
184 size_t destlen);
185void zstd_init_workspace_manager(void);
186void zstd_cleanup_workspace_manager(void);
187struct list_head *zstd_alloc_workspace(int level);
188void zstd_free_workspace(struct list_head *ws);
189struct list_head *zstd_get_workspace(int level);
190void zstd_put_workspace(struct list_head *ws);
191
192#endif