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 <linux/mm.h>
11#include <linux/list.h>
12#include <linux/workqueue.h>
13#include <linux/wait.h>
14#include "bio.h"
15
16struct address_space;
17struct page;
18struct inode;
19struct btrfs_inode;
20struct btrfs_ordered_extent;
21struct btrfs_bio;
22
23/*
24 * We want to make sure that amount of RAM required to uncompress an extent is
25 * reasonable, so we limit the total size in ram of a compressed extent to
26 * 128k.  This is a crucial number because it also controls how easily we can
27 * spread reads across cpus for decompression.
28 *
29 * We also want to make sure the amount of IO required to do a random read is
30 * reasonably small, so we limit the size of a compressed extent to 128k.
31 */
32
33/* Maximum length of compressed data stored on disk */
34#define BTRFS_MAX_COMPRESSED		(SZ_128K)
35#define BTRFS_MAX_COMPRESSED_PAGES	(BTRFS_MAX_COMPRESSED / PAGE_SIZE)
36static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
37
38/* Maximum size of data before compression */
39#define BTRFS_MAX_UNCOMPRESSED		(SZ_128K)
40
41#define	BTRFS_ZLIB_DEFAULT_LEVEL		3
42
43struct compressed_bio {
44	/* Number of compressed pages in the array */
45	unsigned int nr_pages;
46
47	/* the pages with the compressed data on them */
48	struct page **compressed_pages;
49
50	/* starting offset in the inode for our pages */
51	u64 start;
52
53	/* Number of bytes in the inode we're working on */
54	unsigned int len;
55
56	/* Number of bytes on disk */
57	unsigned int compressed_len;
58
59	/* The compression algorithm for this bio */
60	u8 compress_type;
61
62	/* Whether this is a write for writeback. */
63	bool writeback;
64
65	union {
66		/* For reads, this is the bio we are copying the data into */
67		struct btrfs_bio *orig_bbio;
68		struct work_struct write_end_work;
69	};
70
71	/* Must be last. */
72	struct btrfs_bio bbio;
73};
74
75static inline unsigned int btrfs_compress_type(unsigned int type_level)
76{
77	return (type_level & 0xF);
78}
79
80static inline unsigned int btrfs_compress_level(unsigned int type_level)
81{
82	return ((type_level & 0xF0) >> 4);
83}
84
85int __init btrfs_init_compress(void);
86void __cold btrfs_exit_compress(void);
87
88int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
89			 u64 start, struct page **pages,
90			 unsigned long *out_pages,
91			 unsigned long *total_in,
92			 unsigned long *total_out);
93int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page,
94		     unsigned long start_byte, size_t srclen, size_t destlen);
95int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
96			      struct compressed_bio *cb, u32 decompressed);
97
98void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
99				  struct page **compressed_pages,
100				  unsigned int nr_pages,
101				  blk_opf_t write_flags,
102				  bool writeback);
103void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
104
105unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
106
107struct page *btrfs_alloc_compr_page(void);
108void btrfs_free_compr_page(struct page *page);
109
110enum btrfs_compression_type {
111	BTRFS_COMPRESS_NONE  = 0,
112	BTRFS_COMPRESS_ZLIB  = 1,
113	BTRFS_COMPRESS_LZO   = 2,
114	BTRFS_COMPRESS_ZSTD  = 3,
115	BTRFS_NR_COMPRESS_TYPES = 4,
116};
117
118struct workspace_manager {
119	struct list_head idle_ws;
120	spinlock_t ws_lock;
121	/* Number of free workspaces */
122	int free_ws;
123	/* Total number of allocated workspaces */
124	atomic_t total_ws;
125	/* Waiters for a free workspace */
126	wait_queue_head_t ws_wait;
127};
128
129struct list_head *btrfs_get_workspace(int type, unsigned int level);
130void btrfs_put_workspace(int type, struct list_head *ws);
131
132struct btrfs_compress_op {
133	struct workspace_manager *workspace_manager;
134	/* Maximum level supported by the compression algorithm */
135	unsigned int max_level;
136	unsigned int default_level;
137};
138
139/* The heuristic workspaces are managed via the 0th workspace manager */
140#define BTRFS_NR_WORKSPACE_MANAGERS	BTRFS_NR_COMPRESS_TYPES
141
142extern const struct btrfs_compress_op btrfs_heuristic_compress;
143extern const struct btrfs_compress_op btrfs_zlib_compress;
144extern const struct btrfs_compress_op btrfs_lzo_compress;
145extern const struct btrfs_compress_op btrfs_zstd_compress;
146
147const char* btrfs_compress_type2str(enum btrfs_compression_type type);
148bool btrfs_compress_is_valid_type(const char *str, size_t len);
149
150int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
151
152int zlib_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);
155int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
156int zlib_decompress(struct list_head *ws, const u8 *data_in,
157		struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
158		size_t destlen);
159struct list_head *zlib_alloc_workspace(unsigned int level);
160void zlib_free_workspace(struct list_head *ws);
161struct list_head *zlib_get_workspace(unsigned int level);
162
163int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
164		u64 start, struct page **pages, unsigned long *out_pages,
165		unsigned long *total_in, unsigned long *total_out);
166int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
167int lzo_decompress(struct list_head *ws, const u8 *data_in,
168		struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
169		size_t destlen);
170struct list_head *lzo_alloc_workspace(unsigned int level);
171void lzo_free_workspace(struct list_head *ws);
172
173int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
174		u64 start, struct page **pages, unsigned long *out_pages,
175		unsigned long *total_in, unsigned long *total_out);
176int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
177int zstd_decompress(struct list_head *ws, const u8 *data_in,
178		struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
179		size_t destlen);
180void zstd_init_workspace_manager(void);
181void zstd_cleanup_workspace_manager(void);
182struct list_head *zstd_alloc_workspace(unsigned int level);
183void zstd_free_workspace(struct list_head *ws);
184struct list_head *zstd_get_workspace(unsigned int level);
185void zstd_put_workspace(struct list_head *ws);
186
187#endif
188