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 static_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
32 struct compressed_bio {
33 /* Number of outstanding bios */
34 refcount_t pending_ios;
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
63 union {
64 /* For reads, this is the bio we are copying the data into */
65 struct bio *orig_bio;
66 struct work_struct write_end_work;
67 };
68 };
69
btrfs_compress_type(unsigned int type_level)70 static inline unsigned int btrfs_compress_type(unsigned int type_level)
71 {
72 return (type_level & 0xF);
73 }
74
btrfs_compress_level(unsigned int type_level)75 static inline unsigned int btrfs_compress_level(unsigned int type_level)
76 {
77 return ((type_level & 0xF0) >> 4);
78 }
79
80 void __init btrfs_init_compress(void);
81 void __cold btrfs_exit_compress(void);
82
83 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
84 u64 start, struct page **pages,
85 unsigned long *out_pages,
86 unsigned long *total_in,
87 unsigned long *total_out);
88 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
89 unsigned long start_byte, size_t srclen, size_t destlen);
90 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
91 struct compressed_bio *cb, u32 decompressed);
92
93 blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
94 unsigned int len, u64 disk_start,
95 unsigned int compressed_len,
96 struct page **compressed_pages,
97 unsigned int nr_pages,
98 blk_opf_t write_flags,
99 struct cgroup_subsys_state *blkcg_css,
100 bool writeback);
101 void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
102 int mirror_num);
103
104 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
105
106 enum btrfs_compression_type {
107 BTRFS_COMPRESS_NONE = 0,
108 BTRFS_COMPRESS_ZLIB = 1,
109 BTRFS_COMPRESS_LZO = 2,
110 BTRFS_COMPRESS_ZSTD = 3,
111 BTRFS_NR_COMPRESS_TYPES = 4,
112 };
113
114 struct workspace_manager {
115 struct list_head idle_ws;
116 spinlock_t ws_lock;
117 /* Number of free workspaces */
118 int free_ws;
119 /* Total number of allocated workspaces */
120 atomic_t total_ws;
121 /* Waiters for a free workspace */
122 wait_queue_head_t ws_wait;
123 };
124
125 struct list_head *btrfs_get_workspace(int type, unsigned int level);
126 void btrfs_put_workspace(int type, struct list_head *ws);
127
128 struct btrfs_compress_op {
129 struct workspace_manager *workspace_manager;
130 /* Maximum level supported by the compression algorithm */
131 unsigned int max_level;
132 unsigned int default_level;
133 };
134
135 /* The heuristic workspaces are managed via the 0th workspace manager */
136 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
137
138 extern const struct btrfs_compress_op btrfs_heuristic_compress;
139 extern const struct btrfs_compress_op btrfs_zlib_compress;
140 extern const struct btrfs_compress_op btrfs_lzo_compress;
141 extern const struct btrfs_compress_op btrfs_zstd_compress;
142
143 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
144 bool btrfs_compress_is_valid_type(const char *str, size_t len);
145
146 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
147
148 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
149 u64 start, struct page **pages, unsigned long *out_pages,
150 unsigned long *total_in, unsigned long *total_out);
151 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
152 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
153 struct page *dest_page, unsigned long start_byte, size_t srclen,
154 size_t destlen);
155 struct list_head *zlib_alloc_workspace(unsigned int level);
156 void zlib_free_workspace(struct list_head *ws);
157 struct list_head *zlib_get_workspace(unsigned int level);
158
159 int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
160 u64 start, struct page **pages, unsigned long *out_pages,
161 unsigned long *total_in, unsigned long *total_out);
162 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
163 int lzo_decompress(struct list_head *ws, unsigned char *data_in,
164 struct page *dest_page, unsigned long start_byte, size_t srclen,
165 size_t destlen);
166 struct list_head *lzo_alloc_workspace(unsigned int level);
167 void lzo_free_workspace(struct list_head *ws);
168
169 int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
170 u64 start, struct page **pages, unsigned long *out_pages,
171 unsigned long *total_in, unsigned long *total_out);
172 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
173 int zstd_decompress(struct list_head *ws, unsigned char *data_in,
174 struct page *dest_page, unsigned long start_byte, size_t srclen,
175 size_t destlen);
176 void zstd_init_workspace_manager(void);
177 void zstd_cleanup_workspace_manager(void);
178 struct list_head *zstd_alloc_workspace(unsigned int level);
179 void zstd_free_workspace(struct list_head *ws);
180 struct list_head *zstd_get_workspace(unsigned int level);
181 void zstd_put_workspace(struct list_head *ws);
182
183 #endif
184