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 "bio.h"
11
12 struct btrfs_inode;
13 struct btrfs_ordered_extent;
14
15 /*
16 * We want to make sure that amount of RAM required to uncompress an extent is
17 * reasonable, so we limit the total size in ram of a compressed extent to
18 * 128k. This is a crucial number because it also controls how easily we can
19 * spread reads across cpus for decompression.
20 *
21 * We also want to make sure the amount of IO required to do a random read is
22 * reasonably small, so we limit the size of a compressed extent to 128k.
23 */
24
25 /* Maximum length of compressed data stored on disk */
26 #define BTRFS_MAX_COMPRESSED (SZ_128K)
27 #define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
28 static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
29
30 /* Maximum size of data before compression */
31 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
32
33 #define BTRFS_ZLIB_DEFAULT_LEVEL 3
34
35 struct compressed_bio {
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 /* starting offset in the inode for our pages */
43 u64 start;
44
45 /* Number of bytes in the inode we're working on */
46 unsigned int len;
47
48 /* Number of bytes on disk */
49 unsigned int compressed_len;
50
51 /* The compression algorithm for this bio */
52 u8 compress_type;
53
54 /* Whether this is a write for writeback. */
55 bool writeback;
56
57 union {
58 /* For reads, this is the bio we are copying the data into */
59 struct btrfs_bio *orig_bbio;
60 struct work_struct write_end_work;
61 };
62
63 /* Must be last. */
64 struct btrfs_bio bbio;
65 };
66
btrfs_compress_type(unsigned int type_level)67 static inline unsigned int btrfs_compress_type(unsigned int type_level)
68 {
69 return (type_level & 0xF);
70 }
71
btrfs_compress_level(unsigned int type_level)72 static inline unsigned int btrfs_compress_level(unsigned int type_level)
73 {
74 return ((type_level & 0xF0) >> 4);
75 }
76
77 int __init btrfs_init_compress(void);
78 void __cold btrfs_exit_compress(void);
79
80 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
81 u64 start, struct page **pages,
82 unsigned long *out_pages,
83 unsigned long *total_in,
84 unsigned long *total_out);
85 int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page,
86 unsigned long start_byte, size_t srclen, size_t destlen);
87 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
88 struct compressed_bio *cb, u32 decompressed);
89
90 void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
91 struct page **compressed_pages,
92 unsigned int nr_pages,
93 blk_opf_t write_flags,
94 bool writeback);
95 void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
96
97 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
98
99 enum btrfs_compression_type {
100 BTRFS_COMPRESS_NONE = 0,
101 BTRFS_COMPRESS_ZLIB = 1,
102 BTRFS_COMPRESS_LZO = 2,
103 BTRFS_COMPRESS_ZSTD = 3,
104 BTRFS_NR_COMPRESS_TYPES = 4,
105 };
106
107 struct workspace_manager {
108 struct list_head idle_ws;
109 spinlock_t ws_lock;
110 /* Number of free workspaces */
111 int free_ws;
112 /* Total number of allocated workspaces */
113 atomic_t total_ws;
114 /* Waiters for a free workspace */
115 wait_queue_head_t ws_wait;
116 };
117
118 struct list_head *btrfs_get_workspace(int type, unsigned int level);
119 void btrfs_put_workspace(int type, struct list_head *ws);
120
121 struct btrfs_compress_op {
122 struct workspace_manager *workspace_manager;
123 /* Maximum level supported by the compression algorithm */
124 unsigned int max_level;
125 unsigned int default_level;
126 };
127
128 /* The heuristic workspaces are managed via the 0th workspace manager */
129 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
130
131 extern const struct btrfs_compress_op btrfs_heuristic_compress;
132 extern const struct btrfs_compress_op btrfs_zlib_compress;
133 extern const struct btrfs_compress_op btrfs_lzo_compress;
134 extern const struct btrfs_compress_op btrfs_zstd_compress;
135
136 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
137 bool btrfs_compress_is_valid_type(const char *str, size_t len);
138
139 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
140
141 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
142 u64 start, struct page **pages, unsigned long *out_pages,
143 unsigned long *total_in, unsigned long *total_out);
144 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
145 int zlib_decompress(struct list_head *ws, const u8 *data_in,
146 struct page *dest_page, unsigned long start_byte, size_t srclen,
147 size_t destlen);
148 struct list_head *zlib_alloc_workspace(unsigned int level);
149 void zlib_free_workspace(struct list_head *ws);
150 struct list_head *zlib_get_workspace(unsigned int level);
151
152 int lzo_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);
155 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
156 int lzo_decompress(struct list_head *ws, const u8 *data_in,
157 struct page *dest_page, unsigned long start_byte, size_t srclen,
158 size_t destlen);
159 struct list_head *lzo_alloc_workspace(unsigned int level);
160 void lzo_free_workspace(struct list_head *ws);
161
162 int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
163 u64 start, struct page **pages, unsigned long *out_pages,
164 unsigned long *total_in, unsigned long *total_out);
165 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
166 int zstd_decompress(struct list_head *ws, const u8 *data_in,
167 struct page *dest_page, unsigned long start_byte, size_t srclen,
168 size_t destlen);
169 void zstd_init_workspace_manager(void);
170 void zstd_cleanup_workspace_manager(void);
171 struct list_head *zstd_alloc_workspace(unsigned int level);
172 void zstd_free_workspace(struct list_head *ws);
173 struct list_head *zstd_get_workspace(unsigned int level);
174 void zstd_put_workspace(struct list_head *ws);
175
176 #endif
177