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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
11struct btrfs_inode;
12
13/*
14 * We want to make sure that amount of RAM required to uncompress an extent is
15 * reasonable, so we limit the total size in ram of a compressed extent to
16 * 128k. This is a crucial number because it also controls how easily we can
17 * spread reads across cpus for decompression.
18 *
19 * We also want to make sure the amount of IO required to do a random read is
20 * reasonably small, so we limit the size of a compressed extent to 128k.
21 */
22
23/* Maximum length of compressed data stored on disk */
24#define BTRFS_MAX_COMPRESSED (SZ_128K)
25static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
26
27/* Maximum size of data before compression */
28#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
29
30#define BTRFS_ZLIB_DEFAULT_LEVEL 3
31
32struct compressed_bio {
33 /* Number of sectors with unfinished IO (unsubmitted or unfinished) */
34 refcount_t pending_sectors;
35
36 /* Number of compressed pages in the array */
37 unsigned int nr_pages;
38
39 /* the pages with the compressed data on them */
40 struct page **compressed_pages;
41
42 /* inode that owns this data */
43 struct inode *inode;
44
45 /* starting offset in the inode for our pages */
46 u64 start;
47
48 /* Number of bytes in the inode we're working on */
49 unsigned int len;
50
51 /* Number of bytes on disk */
52 unsigned int compressed_len;
53
54 /* The compression algorithm for this bio */
55 u8 compress_type;
56
57 /* Whether this is a write for writeback. */
58 bool writeback;
59
60 /* IO errors */
61 blk_status_t status;
62 int mirror_num;
63
64 /* for reads, this is the bio we are copying the data into */
65 struct bio *orig_bio;
66
67 /*
68 * the start of a variable length array of checksums only
69 * used by reads
70 */
71 u8 sums[];
72};
73
74static inline unsigned int btrfs_compress_type(unsigned int type_level)
75{
76 return (type_level & 0xF);
77}
78
79static inline unsigned int btrfs_compress_level(unsigned int type_level)
80{
81 return ((type_level & 0xF0) >> 4);
82}
83
84void __init btrfs_init_compress(void);
85void __cold btrfs_exit_compress(void);
86
87int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
88 u64 start, struct page **pages,
89 unsigned long *out_pages,
90 unsigned long *total_in,
91 unsigned long *total_out);
92int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
93 unsigned long start_byte, size_t srclen, size_t destlen);
94int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
95 struct compressed_bio *cb, u32 decompressed);
96
97blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
98 unsigned int len, u64 disk_start,
99 unsigned int compressed_len,
100 struct page **compressed_pages,
101 unsigned int nr_pages,
102 unsigned int write_flags,
103 struct cgroup_subsys_state *blkcg_css,
104 bool writeback);
105blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
106 int mirror_num, unsigned long bio_flags);
107
108unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
109
110enum btrfs_compression_type {
111 BTRFS_COMPRESS_NONE = 0,
112 BTRFS_COMPRESS_ZLIB = 1,
113 BTRFS_COMPRESS_LZO = 2,
114 BTRFS_COMPRESS_ZSTD = 3,
115 BTRFS_NR_COMPRESS_TYPES = 4,
116};
117
118struct workspace_manager {
119 struct list_head idle_ws;
120 spinlock_t ws_lock;
121 /* Number of free workspaces */
122 int free_ws;
123 /* Total number of allocated workspaces */
124 atomic_t total_ws;
125 /* Waiters for a free workspace */
126 wait_queue_head_t ws_wait;
127};
128
129struct list_head *btrfs_get_workspace(int type, unsigned int level);
130void btrfs_put_workspace(int type, struct list_head *ws);
131
132struct btrfs_compress_op {
133 struct workspace_manager *workspace_manager;
134 /* Maximum level supported by the compression algorithm */
135 unsigned int max_level;
136 unsigned int default_level;
137};
138
139/* The heuristic workspaces are managed via the 0th workspace manager */
140#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
141
142extern const struct btrfs_compress_op btrfs_heuristic_compress;
143extern const struct btrfs_compress_op btrfs_zlib_compress;
144extern const struct btrfs_compress_op btrfs_lzo_compress;
145extern const struct btrfs_compress_op btrfs_zstd_compress;
146
147const char* btrfs_compress_type2str(enum btrfs_compression_type type);
148bool btrfs_compress_is_valid_type(const char *str, size_t len);
149
150int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
151
152int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
153 u64 start, struct page **pages, unsigned long *out_pages,
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, unsigned char *data_in,
157 struct page *dest_page, unsigned long start_byte, 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_pages(struct list_head *ws, struct address_space *mapping,
164 u64 start, struct page **pages, unsigned long *out_pages,
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, unsigned char *data_in,
168 struct page *dest_page, unsigned long start_byte, 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_pages(struct list_head *ws, struct address_space *mapping,
174 u64 start, struct page **pages, unsigned long *out_pages,
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, unsigned char *data_in,
178 struct page *dest_page, unsigned long start_byte, 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