xref: /openbmc/linux/fs/btrfs/compression.h (revision e6e8c6c2)
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 
70 static inline unsigned int btrfs_compress_type(unsigned int type_level)
71 {
72 	return (type_level & 0xF);
73 }
74 
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