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 struct 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)
25 /* Maximum size of data before compression */
26 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
27
28 #define BTRFS_ZLIB_DEFAULT_LEVEL 3
29
30 struct compressed_bio {
31 /* number of bios pending for this compressed extent */
32 refcount_t pending_bios;
33
34 /* Number of compressed pages in the array */
35 unsigned int nr_pages;
36
37 /* the pages with the compressed data on them */
38 struct page **compressed_pages;
39
40 /* inode that owns this data */
41 struct inode *inode;
42
43 /* starting offset in the inode for our pages */
44 u64 start;
45
46 /* Number of bytes in the inode we're working on */
47 unsigned int len;
48
49 /* Number of bytes on disk */
50 unsigned int compressed_len;
51
52 /* The compression algorithm for this bio */
53 u8 compress_type;
54
55 /* IO errors */
56 u8 errors;
57 int mirror_num;
58
59 /* for reads, this is the bio we are copying the data into */
60 struct bio *orig_bio;
61
62 /*
63 * the start of a variable length array of checksums only
64 * used by reads
65 */
66 u8 sums[];
67 };
68
btrfs_compress_type(unsigned int type_level)69 static inline unsigned int btrfs_compress_type(unsigned int type_level)
70 {
71 return (type_level & 0xF);
72 }
73
btrfs_compress_level(unsigned int type_level)74 static inline unsigned int btrfs_compress_level(unsigned int type_level)
75 {
76 return ((type_level & 0xF0) >> 4);
77 }
78
79 void __init btrfs_init_compress(void);
80 void __cold btrfs_exit_compress(void);
81
82 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
83 u64 start, struct page **pages,
84 unsigned long *out_pages,
85 unsigned long *total_in,
86 unsigned long *total_out);
87 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
88 unsigned long start_byte, size_t srclen, size_t destlen);
89 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
90 struct compressed_bio *cb, u32 decompressed);
91
92 blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
93 unsigned int len, u64 disk_start,
94 unsigned int compressed_len,
95 struct page **compressed_pages,
96 unsigned int nr_pages,
97 unsigned int write_flags,
98 struct cgroup_subsys_state *blkcg_css);
99 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
100 int mirror_num, unsigned long bio_flags);
101
102 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
103
104 enum btrfs_compression_type {
105 BTRFS_COMPRESS_NONE = 0,
106 BTRFS_COMPRESS_ZLIB = 1,
107 BTRFS_COMPRESS_LZO = 2,
108 BTRFS_COMPRESS_ZSTD = 3,
109 BTRFS_NR_COMPRESS_TYPES = 4,
110 };
111
112 struct workspace_manager {
113 struct list_head idle_ws;
114 spinlock_t ws_lock;
115 /* Number of free workspaces */
116 int free_ws;
117 /* Total number of allocated workspaces */
118 atomic_t total_ws;
119 /* Waiters for a free workspace */
120 wait_queue_head_t ws_wait;
121 };
122
123 struct list_head *btrfs_get_workspace(int type, unsigned int level);
124 void btrfs_put_workspace(int type, struct list_head *ws);
125
126 struct btrfs_compress_op {
127 struct workspace_manager *workspace_manager;
128 /* Maximum level supported by the compression algorithm */
129 unsigned int max_level;
130 unsigned int default_level;
131 };
132
133 /* The heuristic workspaces are managed via the 0th workspace manager */
134 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
135
136 extern const struct btrfs_compress_op btrfs_heuristic_compress;
137 extern const struct btrfs_compress_op btrfs_zlib_compress;
138 extern const struct btrfs_compress_op btrfs_lzo_compress;
139 extern const struct btrfs_compress_op btrfs_zstd_compress;
140
141 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
142 bool btrfs_compress_is_valid_type(const char *str, size_t len);
143
144 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
145
146 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
147 u64 start, struct page **pages, unsigned long *out_pages,
148 unsigned long *total_in, unsigned long *total_out);
149 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
150 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
151 struct page *dest_page, unsigned long start_byte, size_t srclen,
152 size_t destlen);
153 struct list_head *zlib_alloc_workspace(unsigned int level);
154 void zlib_free_workspace(struct list_head *ws);
155 struct list_head *zlib_get_workspace(unsigned int level);
156
157 int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
158 u64 start, struct page **pages, unsigned long *out_pages,
159 unsigned long *total_in, unsigned long *total_out);
160 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
161 int lzo_decompress(struct list_head *ws, unsigned char *data_in,
162 struct page *dest_page, unsigned long start_byte, size_t srclen,
163 size_t destlen);
164 struct list_head *lzo_alloc_workspace(unsigned int level);
165 void lzo_free_workspace(struct list_head *ws);
166
167 int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
168 u64 start, struct page **pages, unsigned long *out_pages,
169 unsigned long *total_in, unsigned long *total_out);
170 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
171 int zstd_decompress(struct list_head *ws, unsigned char *data_in,
172 struct page *dest_page, unsigned long start_byte, size_t srclen,
173 size_t destlen);
174 void zstd_init_workspace_manager(void);
175 void zstd_cleanup_workspace_manager(void);
176 struct list_head *zstd_alloc_workspace(unsigned int level);
177 void zstd_free_workspace(struct list_head *ws);
178 struct list_head *zstd_get_workspace(unsigned int level);
179 void zstd_put_workspace(struct list_head *ws);
180
181 #endif
182