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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 "bio.h"
15
16struct address_space;
17struct page;
18struct inode;
19struct btrfs_inode;
20struct btrfs_ordered_extent;
21struct btrfs_bio;
22
23/*
24 * We want to make sure that amount of RAM required to uncompress an extent is
25 * reasonable, so we limit the total size in ram of a compressed extent to
26 * 128k. This is a crucial number because it also controls how easily we can
27 * spread reads across cpus for decompression.
28 *
29 * We also want to make sure the amount of IO required to do a random read is
30 * reasonably small, so we limit the size of a compressed extent to 128k.
31 */
32
33/* Maximum length of compressed data stored on disk */
34#define BTRFS_MAX_COMPRESSED (SZ_128K)
35#define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
36static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
37
38/* Maximum size of data before compression */
39#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
40
41#define BTRFS_ZLIB_DEFAULT_LEVEL 3
42
43struct compressed_bio {
44 /* Number of compressed folios in the array. */
45 unsigned int nr_folios;
46
47 /* The folios with the compressed data on them. */
48 struct folio **compressed_folios;
49
50 /* starting offset in the inode for our pages */
51 u64 start;
52
53 /* Number of bytes in the inode we're working on */
54 unsigned int len;
55
56 /* Number of bytes on disk */
57 unsigned int compressed_len;
58
59 /* The compression algorithm for this bio */
60 u8 compress_type;
61
62 /* Whether this is a write for writeback. */
63 bool writeback;
64
65 union {
66 /* For reads, this is the bio we are copying the data into */
67 struct btrfs_bio *orig_bbio;
68 struct work_struct write_end_work;
69 };
70
71 /* Must be last. */
72 struct btrfs_bio bbio;
73};
74
75static inline unsigned int btrfs_compress_type(unsigned int type_level)
76{
77 return (type_level & 0xF);
78}
79
80static inline unsigned int btrfs_compress_level(unsigned int type_level)
81{
82 return ((type_level & 0xF0) >> 4);
83}
84
85int __init btrfs_init_compress(void);
86void __cold btrfs_exit_compress(void);
87
88int btrfs_compress_folios(unsigned int type_level, struct address_space *mapping,
89 u64 start, struct folio **folios, unsigned long *out_folios,
90 unsigned long *total_in, unsigned long *total_out);
91int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page,
92 unsigned long start_byte, size_t srclen, size_t destlen);
93int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
94 struct compressed_bio *cb, u32 decompressed);
95
96void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
97 struct folio **compressed_folios,
98 unsigned int nr_folios, blk_opf_t write_flags,
99 bool writeback);
100void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
101
102unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
103
104struct folio *btrfs_alloc_compr_folio(void);
105void btrfs_free_compr_folio(struct folio *folio);
106
107enum btrfs_compression_type {
108 BTRFS_COMPRESS_NONE = 0,
109 BTRFS_COMPRESS_ZLIB = 1,
110 BTRFS_COMPRESS_LZO = 2,
111 BTRFS_COMPRESS_ZSTD = 3,
112 BTRFS_NR_COMPRESS_TYPES = 4,
113};
114
115struct workspace_manager {
116 struct list_head idle_ws;
117 spinlock_t ws_lock;
118 /* Number of free workspaces */
119 int free_ws;
120 /* Total number of allocated workspaces */
121 atomic_t total_ws;
122 /* Waiters for a free workspace */
123 wait_queue_head_t ws_wait;
124};
125
126struct list_head *btrfs_get_workspace(int type, unsigned int level);
127void btrfs_put_workspace(int type, struct list_head *ws);
128
129struct btrfs_compress_op {
130 struct workspace_manager *workspace_manager;
131 /* Maximum level supported by the compression algorithm */
132 unsigned int max_level;
133 unsigned int default_level;
134};
135
136/* The heuristic workspaces are managed via the 0th workspace manager */
137#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
138
139extern const struct btrfs_compress_op btrfs_heuristic_compress;
140extern const struct btrfs_compress_op btrfs_zlib_compress;
141extern const struct btrfs_compress_op btrfs_lzo_compress;
142extern const struct btrfs_compress_op btrfs_zstd_compress;
143
144const char* btrfs_compress_type2str(enum btrfs_compression_type type);
145bool btrfs_compress_is_valid_type(const char *str, size_t len);
146
147int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
148
149int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
150 struct folio **in_folio_ret);
151
152int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
153 u64 start, struct folio **folios, unsigned long *out_folios,
154 unsigned long *total_in, unsigned long *total_out);
155int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
156int zlib_decompress(struct list_head *ws, const u8 *data_in,
157 struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
158 size_t destlen);
159struct list_head *zlib_alloc_workspace(unsigned int level);
160void zlib_free_workspace(struct list_head *ws);
161struct list_head *zlib_get_workspace(unsigned int level);
162
163int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
164 u64 start, struct folio **folios, unsigned long *out_folios,
165 unsigned long *total_in, unsigned long *total_out);
166int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
167int lzo_decompress(struct list_head *ws, const u8 *data_in,
168 struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
169 size_t destlen);
170struct list_head *lzo_alloc_workspace(unsigned int level);
171void lzo_free_workspace(struct list_head *ws);
172
173int zstd_compress_folios(struct list_head *ws, struct address_space *mapping,
174 u64 start, struct folio **folios, unsigned long *out_folios,
175 unsigned long *total_in, unsigned long *total_out);
176int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
177int zstd_decompress(struct list_head *ws, const u8 *data_in,
178 struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
179 size_t destlen);
180void zstd_init_workspace_manager(void);
181void zstd_cleanup_workspace_manager(void);
182struct list_head *zstd_alloc_workspace(unsigned int level);
183void zstd_free_workspace(struct list_head *ws);
184struct list_head *zstd_get_workspace(unsigned int level);
185void zstd_put_workspace(struct list_head *ws);
186
187#endif