linux - fs/btrfs/compression.h

183 lines · 6.4 KiB

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 <linux/pagemap.h>
15	#include "bio.h"
16	#include "fs.h"
17	#include "btrfs_inode.h"
18
19	struct address_space;
20	struct inode;
21	struct btrfs_inode;
22	struct btrfs_ordered_extent;
23
24	/*
25	* We want to make sure that amount of RAM required to uncompress an extent is
26	* reasonable, so we limit the total size in ram of a compressed extent to
27	* 128k. This is a crucial number because it also controls how easily we can
28	* spread reads across cpus for decompression.
29	*
30	* We also want to make sure the amount of IO required to do a random read is
31	* reasonably small, so we limit the size of a compressed extent to 128k.
32	*/
33
34	/* Maximum length of compressed data stored on disk */
35	#define BTRFS_MAX_COMPRESSED (SZ_128K)
36	#define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
37	static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
38
39	/* The max size for a single worker to compress. */
40	#define BTRFS_COMPRESSION_CHUNK_SIZE (SZ_512K)
41
42	/* Maximum size of data before compression */
43	#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
44
45	#define BTRFS_ZLIB_DEFAULT_LEVEL 3
46
47	struct compressed_bio {
48	/* starting offset in the inode for our pages */
49	u64 start;
50
51	/* Number of bytes in the inode we're working on */
52	unsigned int 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	/* For reads, this is the bio we are copying the data into. */
61	struct btrfs_bio *orig_bbio;
62
63	/* Must be last. */
64	struct btrfs_bio bbio;
65	};
66
67	static inline struct btrfs_fs_info cb_to_fs_info(const struct compressed_bio cb)
68	{
69	return cb->bbio.inode->root->fs_info;
70	}
71
72	/* @range_end must be exclusive. */
73	static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u64 cur)
74	{
75	/* @cur must be inside the folio. */
76	ASSERT(folio_pos(folio) <= cur);
77	ASSERT(cur < folio_next_pos(folio));
78	return umin(range_end, folio_next_pos(folio)) - cur;
79	}
80
81	int btrfs_alloc_compress_wsm(struct btrfs_fs_info *fs_info);
82	void btrfs_free_compress_wsm(struct btrfs_fs_info *fs_info);
83
84	int __init btrfs_init_compress(void);
85	void __cold btrfs_exit_compress(void);
86
87	bool btrfs_compress_level_valid(unsigned int type, int level);
88	int btrfs_decompress(int type, const u8 data_in, struct folio dest_folio,
89	unsigned long dest_pgoff, 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	struct compressed_bio btrfs_alloc_compressed_write(struct btrfs_inode inode,
94	u64 start, u64 len);
95	void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
96	struct compressed_bio *cb);
97	void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
98
99	int btrfs_compress_str2level(unsigned int type, const char str, int level_ret);
100
101	struct folio btrfs_alloc_compr_folio(struct btrfs_fs_info fs_info, gfp_t gfp);
102	void btrfs_free_compr_folio(struct folio *folio);
103
104	struct workspace_manager {
105	struct list_head idle_ws;
106	spinlock_t ws_lock;
107	/* Number of free workspaces */
108	int free_ws;
109	/* Total number of allocated workspaces */
110	atomic_t total_ws;
111	/* Waiters for a free workspace */
112	wait_queue_head_t ws_wait;
113	};
114
115	struct list_head btrfs_get_workspace(struct btrfs_fs_info fs_info, int type, int level);
116	void btrfs_put_workspace(struct btrfs_fs_info fs_info, int type, struct list_head ws);
117
118	struct btrfs_compress_levels {
119	/* Maximum level supported by the compression algorithm */
120	int min_level;
121	int max_level;
122	int default_level;
123	};
124
125	/* The heuristic workspaces are managed via the 0th workspace manager */
126	#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
127
128	extern const struct btrfs_compress_levels btrfs_heuristic_compress;
129	extern const struct btrfs_compress_levels btrfs_zlib_compress;
130	extern const struct btrfs_compress_levels btrfs_lzo_compress;
131	extern const struct btrfs_compress_levels btrfs_zstd_compress;
132
133	const char* btrfs_compress_type2str(enum btrfs_compression_type type);
134	bool btrfs_compress_is_valid_type(const char *str, size_t len);
135
136	int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
137
138	int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
139	struct folio **in_folio_ret);
140	struct compressed_bio btrfs_compress_bio(struct btrfs_inode inode,
141	u64 start, u32 len, unsigned int type,
142	int level, blk_opf_t write_flags);
143
144	static inline void cleanup_compressed_bio(struct compressed_bio *cb)
145	{
146	struct bio *bio = &cb->bbio.bio;
147	struct folio_iter fi;
148
149	bio_for_each_folio_all(fi, bio)
150	btrfs_free_compr_folio(fi.folio);
151	bio_put(bio);
152	}
153
154	int zlib_compress_bio(struct list_head ws, struct compressed_bio cb);
155	int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb);
156	int zlib_decompress(struct list_head ws, const u8 data_in,
157	struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
158	size_t destlen);
159	struct list_head zlib_alloc_workspace(struct btrfs_fs_info fs_info, unsigned int level);
160	void zlib_free_workspace(struct list_head *ws);
161	struct list_head zlib_get_workspace(struct btrfs_fs_info fs_info, unsigned int level);
162
163	int lzo_compress_bio(struct list_head ws, struct compressed_bio cb);
164	int lzo_decompress_bio(struct list_head ws, struct compressed_bio cb);
165	int lzo_decompress(struct list_head ws, const u8 data_in,
166	struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
167	size_t destlen);
168	struct list_head lzo_alloc_workspace(struct btrfs_fs_info fs_info);
169	void lzo_free_workspace(struct list_head *ws);
170
171	int zstd_compress_bio(struct list_head ws, struct compressed_bio cb);
172	int zstd_decompress_bio(struct list_head ws, struct compressed_bio cb);
173	int zstd_decompress(struct list_head ws, const u8 data_in,
174	struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
175	size_t destlen);
176	int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info);
177	void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info);
178	struct list_head zstd_alloc_workspace(struct btrfs_fs_info fs_info, int level);
179	void zstd_free_workspace(struct list_head *ws);
180	struct list_head zstd_get_workspace(struct btrfs_fs_info fs_info, int level);
181	void zstd_put_workspace(struct btrfs_fs_info fs_info, struct list_head ws);
182
183	#endif