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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
11/*
12 * We want to make sure that amount of RAM required to uncompress an extent is
13 * reasonable, so we limit the total size in ram of a compressed extent to
14 * 128k. This is a crucial number because it also controls how easily we can
15 * spread reads across cpus for decompression.
16 *
17 * We also want to make sure the amount of IO required to do a random read is
18 * reasonably small, so we limit the size of a compressed extent to 128k.
19 */
20
21/* Maximum length of compressed data stored on disk */
22#define BTRFS_MAX_COMPRESSED (SZ_128K)
23/* Maximum size of data before compression */
24#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
25
26#define BTRFS_ZLIB_DEFAULT_LEVEL 3
27
28struct compressed_bio {
29 /* number of bios pending for this compressed extent */
30 refcount_t pending_bios;
31
32 /* the pages with the compressed data on them */
33 struct page **compressed_pages;
34
35 /* inode that owns this data */
36 struct inode *inode;
37
38 /* starting offset in the inode for our pages */
39 u64 start;
40
41 /* number of bytes in the inode we're working on */
42 unsigned long len;
43
44 /* number of bytes on disk */
45 unsigned long compressed_len;
46
47 /* the compression algorithm for this bio */
48 int compress_type;
49
50 /* number of compressed pages in the array */
51 unsigned long nr_pages;
52
53 /* IO errors */
54 int errors;
55 int mirror_num;
56
57 /* for reads, this is the bio we are copying the data into */
58 struct bio *orig_bio;
59
60 /*
61 * the start of a variable length array of checksums only
62 * used by reads
63 */
64 u32 sums;
65};
66
67void __init btrfs_init_compress(void);
68void __cold btrfs_exit_compress(void);
69
70int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
71 u64 start, struct page **pages,
72 unsigned long *out_pages,
73 unsigned long *total_in,
74 unsigned long *total_out);
75int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
76 unsigned long start_byte, size_t srclen, size_t destlen);
77int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
78 unsigned long total_out, u64 disk_start,
79 struct bio *bio);
80
81blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
82 unsigned long len, u64 disk_start,
83 unsigned long compressed_len,
84 struct page **compressed_pages,
85 unsigned long nr_pages,
86 unsigned int write_flags);
87blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
88 int mirror_num, unsigned long bio_flags);
89
90unsigned btrfs_compress_str2level(const char *str);
91
92enum btrfs_compression_type {
93 BTRFS_COMPRESS_NONE = 0,
94 BTRFS_COMPRESS_ZLIB = 1,
95 BTRFS_COMPRESS_LZO = 2,
96 BTRFS_COMPRESS_ZSTD = 3,
97 BTRFS_COMPRESS_TYPES = 3,
98};
99
100struct btrfs_compress_op {
101 struct list_head *(*alloc_workspace)(void);
102
103 void (*free_workspace)(struct list_head *workspace);
104
105 int (*compress_pages)(struct list_head *workspace,
106 struct address_space *mapping,
107 u64 start,
108 struct page **pages,
109 unsigned long *out_pages,
110 unsigned long *total_in,
111 unsigned long *total_out);
112
113 int (*decompress_bio)(struct list_head *workspace,
114 struct compressed_bio *cb);
115
116 int (*decompress)(struct list_head *workspace,
117 unsigned char *data_in,
118 struct page *dest_page,
119 unsigned long start_byte,
120 size_t srclen, size_t destlen);
121
122 void (*set_level)(struct list_head *ws, unsigned int type);
123};
124
125extern const struct btrfs_compress_op btrfs_zlib_compress;
126extern const struct btrfs_compress_op btrfs_lzo_compress;
127extern const struct btrfs_compress_op btrfs_zstd_compress;
128
129const char* btrfs_compress_type2str(enum btrfs_compression_type type);
130
131int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
132
133#endif