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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/blk_types.h>
10#include <linux/sizes.h>
11
12struct btrfs_inode;
13
14/*
15 * We want to make sure that amount of RAM required to uncompress an extent is
16 * reasonable, so we limit the total size in ram of a compressed extent to
17 * 128k. This is a crucial number because it also controls how easily we can
18 * spread reads across cpus for decompression.
19 *
20 * We also want to make sure the amount of IO required to do a random read is
21 * reasonably small, so we limit the size of a compressed extent to 128k.
22 */
23
24/* Maximum length of compressed data stored on disk */
25#define BTRFS_MAX_COMPRESSED (SZ_128K)
26static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
27
28/* Maximum size of data before compression */
29#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
30
31#define BTRFS_ZLIB_DEFAULT_LEVEL 3
32
33struct compressed_bio {
34 /* Number of outstanding bios */
35 refcount_t pending_ios;
36
37 /* Number of compressed pages in the array */
38 unsigned int nr_pages;
39
40 /* the pages with the compressed data on them */
41 struct page **compressed_pages;
42
43 /* inode that owns this data */
44 struct inode *inode;
45
46 /* starting offset in the inode for our pages */
47 u64 start;
48
49 /* Number of bytes in the inode we're working on */
50 unsigned int len;
51
52 /* Number of bytes on disk */
53 unsigned int compressed_len;
54
55 /* The compression algorithm for this bio */
56 u8 compress_type;
57
58 /* Whether this is a write for writeback. */
59 bool writeback;
60
61 /* IO errors */
62 blk_status_t status;
63
64 union {
65 /* For reads, this is the bio we are copying the data into */
66 struct bio *orig_bio;
67 struct work_struct write_end_work;
68 };
69};
70
71static inline unsigned int btrfs_compress_type(unsigned int type_level)
72{
73 return (type_level & 0xF);
74}
75
76static inline unsigned int btrfs_compress_level(unsigned int type_level)
77{
78 return ((type_level & 0xF0) >> 4);
79}
80
81int __init btrfs_init_compress(void);
82void __cold btrfs_exit_compress(void);
83
84int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
85 u64 start, struct page **pages,
86 unsigned long *out_pages,
87 unsigned long *total_in,
88 unsigned long *total_out);
89int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page,
90 unsigned long start_byte, size_t srclen, size_t destlen);
91int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
92 struct compressed_bio *cb, u32 decompressed);
93
94blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
95 unsigned int len, u64 disk_start,
96 unsigned int compressed_len,
97 struct page **compressed_pages,
98 unsigned int nr_pages,
99 blk_opf_t write_flags,
100 struct cgroup_subsys_state *blkcg_css,
101 bool writeback);
102void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
103 int mirror_num);
104
105unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
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 zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
150 u64 start, struct page **pages, unsigned long *out_pages,
151 unsigned long *total_in, unsigned long *total_out);
152int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
153int zlib_decompress(struct list_head *ws, const u8 *data_in,
154 struct page *dest_page, unsigned long start_byte, size_t srclen,
155 size_t destlen);
156struct list_head *zlib_alloc_workspace(unsigned int level);
157void zlib_free_workspace(struct list_head *ws);
158struct list_head *zlib_get_workspace(unsigned int level);
159
160int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
161 u64 start, struct page **pages, unsigned long *out_pages,
162 unsigned long *total_in, unsigned long *total_out);
163int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
164int lzo_decompress(struct list_head *ws, const u8 *data_in,
165 struct page *dest_page, unsigned long start_byte, size_t srclen,
166 size_t destlen);
167struct list_head *lzo_alloc_workspace(unsigned int level);
168void lzo_free_workspace(struct list_head *ws);
169
170int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
171 u64 start, struct page **pages, unsigned long *out_pages,
172 unsigned long *total_in, unsigned long *total_out);
173int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
174int zstd_decompress(struct list_head *ws, const u8 *data_in,
175 struct page *dest_page, unsigned long start_byte, size_t srclen,
176 size_t destlen);
177void zstd_init_workspace_manager(void);
178void zstd_cleanup_workspace_manager(void);
179struct list_head *zstd_alloc_workspace(unsigned int level);
180void zstd_free_workspace(struct list_head *ws);
181struct list_head *zstd_get_workspace(unsigned int level);
182void zstd_put_workspace(struct list_head *ws);
183
184#endif