compression.h revision 1c3dc173
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
11struct 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
30struct 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
69static inline unsigned int btrfs_compress_type(unsigned int type_level)
70{
71	return (type_level & 0xF);
72}
73
74static inline unsigned int btrfs_compress_level(unsigned int type_level)
75{
76	return ((type_level & 0xF0) >> 4);
77}
78
79void __init btrfs_init_compress(void);
80void __cold btrfs_exit_compress(void);
81
82int 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);
87int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
88		     unsigned long start_byte, size_t srclen, size_t destlen);
89int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
90			      struct compressed_bio *cb, u32 decompressed);
91
92blk_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);
99blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
100				 int mirror_num, unsigned long bio_flags);
101
102unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
103
104enum 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
112struct 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
123struct list_head *btrfs_get_workspace(int type, unsigned int level);
124void btrfs_put_workspace(int type, struct list_head *ws);
125
126struct 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
136extern const struct btrfs_compress_op btrfs_heuristic_compress;
137extern const struct btrfs_compress_op btrfs_zlib_compress;
138extern const struct btrfs_compress_op btrfs_lzo_compress;
139extern const struct btrfs_compress_op btrfs_zstd_compress;
140
141const char* btrfs_compress_type2str(enum btrfs_compression_type type);
142bool btrfs_compress_is_valid_type(const char *str, size_t len);
143
144int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
145
146int 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);
149int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
150int 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);
153struct list_head *zlib_alloc_workspace(unsigned int level);
154void zlib_free_workspace(struct list_head *ws);
155struct list_head *zlib_get_workspace(unsigned int level);
156
157int 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);
160int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
161int 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);
164struct list_head *lzo_alloc_workspace(unsigned int level);
165void lzo_free_workspace(struct list_head *ws);
166
167int 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);
170int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
171int 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);
174void zstd_init_workspace_manager(void);
175void zstd_cleanup_workspace_manager(void);
176struct list_head *zstd_alloc_workspace(unsigned int level);
177void zstd_free_workspace(struct list_head *ws);
178struct list_head *zstd_get_workspace(unsigned int level);
179void zstd_put_workspace(struct list_head *ws);
180
181#endif
182