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
16 struct address_space;
17 struct page;
18 struct inode;
19 struct btrfs_inode;
20 struct btrfs_ordered_extent;
21 struct 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)
36 static_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
43 struct compressed_bio {
44 /* Number of compressed folios in the array. */
45 unsigned int nr_folios;
46
47 /* The folios with the compressed data on them. */
48 struct folio **compressed_folios;
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
btrfs_compress_type(unsigned int type_level)75 static inline unsigned int btrfs_compress_type(unsigned int type_level)
76 {
77 return (type_level & 0xF);
78 }
79
btrfs_compress_level(unsigned int type_level)80 static inline unsigned int btrfs_compress_level(unsigned int type_level)
81 {
82 return ((type_level & 0xF0) >> 4);
83 }
84
85 /* @range_end must be exclusive. */
btrfs_calc_input_length(u64 range_end,u64 cur)86 static inline u32 btrfs_calc_input_length(u64 range_end, u64 cur)
87 {
88 u64 page_end = round_down(cur, PAGE_SIZE) + PAGE_SIZE;
89
90 return min(range_end, page_end) - cur;
91 }
92
93 int __init btrfs_init_compress(void);
94 void __cold btrfs_exit_compress(void);
95
96 int btrfs_compress_folios(unsigned int type_level, struct address_space *mapping,
97 u64 start, struct folio **folios, unsigned long *out_folios,
98 unsigned long *total_in, unsigned long *total_out);
99 int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
100 unsigned long start_byte, size_t srclen, size_t destlen);
101 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
102 struct compressed_bio *cb, u32 decompressed);
103
104 void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
105 struct folio **compressed_folios,
106 unsigned int nr_folios, blk_opf_t write_flags,
107 bool writeback);
108 void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
109
110 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
111
112 struct folio *btrfs_alloc_compr_folio(void);
113 void btrfs_free_compr_folio(struct folio *folio);
114
115 enum btrfs_compression_type {
116 BTRFS_COMPRESS_NONE = 0,
117 BTRFS_COMPRESS_ZLIB = 1,
118 BTRFS_COMPRESS_LZO = 2,
119 BTRFS_COMPRESS_ZSTD = 3,
120 BTRFS_NR_COMPRESS_TYPES = 4,
121 };
122
123 struct workspace_manager {
124 struct list_head idle_ws;
125 spinlock_t ws_lock;
126 /* Number of free workspaces */
127 int free_ws;
128 /* Total number of allocated workspaces */
129 atomic_t total_ws;
130 /* Waiters for a free workspace */
131 wait_queue_head_t ws_wait;
132 };
133
134 struct list_head *btrfs_get_workspace(int type, unsigned int level);
135 void btrfs_put_workspace(int type, struct list_head *ws);
136
137 struct btrfs_compress_op {
138 struct workspace_manager *workspace_manager;
139 /* Maximum level supported by the compression algorithm */
140 unsigned int max_level;
141 unsigned int default_level;
142 };
143
144 /* The heuristic workspaces are managed via the 0th workspace manager */
145 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
146
147 extern const struct btrfs_compress_op btrfs_heuristic_compress;
148 extern const struct btrfs_compress_op btrfs_zlib_compress;
149 extern const struct btrfs_compress_op btrfs_lzo_compress;
150 extern const struct btrfs_compress_op btrfs_zstd_compress;
151
152 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
153 bool btrfs_compress_is_valid_type(const char *str, size_t len);
154
155 int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
156
157 int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
158 struct folio **in_folio_ret);
159
160 int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
161 u64 start, struct folio **folios, unsigned long *out_folios,
162 unsigned long *total_in, unsigned long *total_out);
163 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
164 int zlib_decompress(struct list_head *ws, const u8 *data_in,
165 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
166 size_t destlen);
167 struct list_head *zlib_alloc_workspace(unsigned int level);
168 void zlib_free_workspace(struct list_head *ws);
169 struct list_head *zlib_get_workspace(unsigned int level);
170
171 int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
172 u64 start, struct folio **folios, unsigned long *out_folios,
173 unsigned long *total_in, unsigned long *total_out);
174 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
175 int lzo_decompress(struct list_head *ws, const u8 *data_in,
176 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
177 size_t destlen);
178 struct list_head *lzo_alloc_workspace(unsigned int level);
179 void lzo_free_workspace(struct list_head *ws);
180
181 int zstd_compress_folios(struct list_head *ws, struct address_space *mapping,
182 u64 start, struct folio **folios, unsigned long *out_folios,
183 unsigned long *total_in, unsigned long *total_out);
184 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
185 int zstd_decompress(struct list_head *ws, const u8 *data_in,
186 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
187 size_t destlen);
188 void zstd_init_workspace_manager(void);
189 void zstd_cleanup_workspace_manager(void);
190 struct list_head *zstd_alloc_workspace(unsigned int level);
191 void zstd_free_workspace(struct list_head *ws);
192 struct list_head *zstd_get_workspace(unsigned int level);
193 void zstd_put_workspace(struct list_head *ws);
194
195 #endif
196