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
28 struct 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 u8 sums[];
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 void __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, unsigned char *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, unsigned long buf_start,
88 unsigned long total_out, u64 disk_start,
89 struct bio *bio);
90
91 blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
92 unsigned long len, u64 disk_start,
93 unsigned long compressed_len,
94 struct page **compressed_pages,
95 unsigned long nr_pages,
96 unsigned int write_flags);
97 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
98 int mirror_num, unsigned long bio_flags);
99
100 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
101
102 enum btrfs_compression_type {
103 BTRFS_COMPRESS_NONE = 0,
104 BTRFS_COMPRESS_ZLIB = 1,
105 BTRFS_COMPRESS_LZO = 2,
106 BTRFS_COMPRESS_ZSTD = 3,
107 BTRFS_COMPRESS_TYPES = 3,
108 };
109
110 struct workspace_manager {
111 const struct btrfs_compress_op *ops;
112 struct list_head idle_ws;
113 spinlock_t ws_lock;
114 /* Number of free workspaces */
115 int free_ws;
116 /* Total number of allocated workspaces */
117 atomic_t total_ws;
118 /* Waiters for a free workspace */
119 wait_queue_head_t ws_wait;
120 };
121
122 void btrfs_init_workspace_manager(struct workspace_manager *wsm,
123 const struct btrfs_compress_op *ops);
124 struct list_head *btrfs_get_workspace(struct workspace_manager *wsm,
125 unsigned int level);
126 void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws);
127 void btrfs_cleanup_workspace_manager(struct workspace_manager *wsm);
128
129 struct btrfs_compress_op {
130 void (*init_workspace_manager)(void);
131
132 void (*cleanup_workspace_manager)(void);
133
134 struct list_head *(*get_workspace)(unsigned int level);
135
136 void (*put_workspace)(struct list_head *ws);
137
138 struct list_head *(*alloc_workspace)(unsigned int level);
139
140 void (*free_workspace)(struct list_head *workspace);
141
142 int (*compress_pages)(struct list_head *workspace,
143 struct address_space *mapping,
144 u64 start,
145 struct page **pages,
146 unsigned long *out_pages,
147 unsigned long *total_in,
148 unsigned long *total_out);
149
150 int (*decompress_bio)(struct list_head *workspace,
151 struct compressed_bio *cb);
152
153 int (*decompress)(struct list_head *workspace,
154 unsigned char *data_in,
155 struct page *dest_page,
156 unsigned long start_byte,
157 size_t srclen, size_t destlen);
158
159 /* Maximum level supported by the compression algorithm */
160 unsigned int max_level;
161 unsigned int default_level;
162 };
163
164 /* The heuristic workspaces are managed via the 0th workspace manager */
165 #define BTRFS_NR_WORKSPACE_MANAGERS (BTRFS_COMPRESS_TYPES + 1)
166
167 extern const struct btrfs_compress_op btrfs_heuristic_compress;
168 extern const struct btrfs_compress_op btrfs_zlib_compress;
169 extern const struct btrfs_compress_op btrfs_lzo_compress;
170 extern const struct btrfs_compress_op btrfs_zstd_compress;
171
172 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
173 bool btrfs_compress_is_valid_type(const char *str, size_t len);
174
175 unsigned int btrfs_compress_set_level(int type, unsigned level);
176
177 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
178
179 #endif
180