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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 "messages.h"
18
19struct address_space;
20struct page;
21struct inode;
22struct btrfs_inode;
23struct btrfs_ordered_extent;
24struct btrfs_bio;
25
26/*
27 * We want to make sure that amount of RAM required to uncompress an extent is
28 * reasonable, so we limit the total size in ram of a compressed extent to
29 * 128k. This is a crucial number because it also controls how easily we can
30 * spread reads across cpus for decompression.
31 *
32 * We also want to make sure the amount of IO required to do a random read is
33 * reasonably small, so we limit the size of a compressed extent to 128k.
34 */
35
36/* Maximum length of compressed data stored on disk */
37#define BTRFS_MAX_COMPRESSED (SZ_128K)
38#define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
39static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
40
41/* Maximum size of data before compression */
42#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
43
44#define BTRFS_ZLIB_DEFAULT_LEVEL 3
45
46struct compressed_bio {
47 /* Number of compressed folios in the array. */
48 unsigned int nr_folios;
49
50 /* The folios with the compressed data on them. */
51 struct folio **compressed_folios;
52
53 /* starting offset in the inode for our pages */
54 u64 start;
55
56 /* Number of bytes in the inode we're working on */
57 unsigned int len;
58
59 /* Number of bytes on disk */
60 unsigned int compressed_len;
61
62 /* The compression algorithm for this bio */
63 u8 compress_type;
64
65 /* Whether this is a write for writeback. */
66 bool writeback;
67
68 union {
69 /* For reads, this is the bio we are copying the data into */
70 struct btrfs_bio *orig_bbio;
71 struct work_struct write_end_work;
72 };
73
74 /* Must be last. */
75 struct btrfs_bio bbio;
76};
77
78static inline struct btrfs_fs_info *cb_to_fs_info(const struct compressed_bio *cb)
79{
80 return cb->bbio.fs_info;
81}
82
83/* @range_end must be exclusive. */
84static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u64 cur)
85{
86 /* @cur must be inside the folio. */
87 ASSERT(folio_pos(folio) <= cur);
88 ASSERT(cur < folio_end(folio));
89 return min(range_end, folio_end(folio)) - cur;
90}
91
92int btrfs_alloc_compress_wsm(struct btrfs_fs_info *fs_info);
93void btrfs_free_compress_wsm(struct btrfs_fs_info *fs_info);
94
95int __init btrfs_init_compress(void);
96void __cold btrfs_exit_compress(void);
97
98bool btrfs_compress_level_valid(unsigned int type, int level);
99int btrfs_compress_folios(unsigned int type, int level, struct btrfs_inode *inode,
100 u64 start, struct folio **folios, unsigned long *out_folios,
101 unsigned long *total_in, unsigned long *total_out);
102int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
103 unsigned long start_byte, size_t srclen, size_t destlen);
104int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
105 struct compressed_bio *cb, u32 decompressed);
106
107void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
108 struct folio **compressed_folios,
109 unsigned int nr_folios, blk_opf_t write_flags,
110 bool writeback);
111void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
112
113int btrfs_compress_str2level(unsigned int type, const char *str, int *level_ret);
114
115struct folio *btrfs_alloc_compr_folio(struct btrfs_fs_info *fs_info);
116void btrfs_free_compr_folio(struct folio *folio);
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(struct btrfs_fs_info *fs_info, int type, int level);
130void btrfs_put_workspace(struct btrfs_fs_info *fs_info, int type, struct list_head *ws);
131
132struct btrfs_compress_levels {
133 /* Maximum level supported by the compression algorithm */
134 int min_level;
135 int max_level;
136 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_levels btrfs_heuristic_compress;
143extern const struct btrfs_compress_levels btrfs_zlib_compress;
144extern const struct btrfs_compress_levels btrfs_lzo_compress;
145extern const struct btrfs_compress_levels 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 btrfs_inode *inode, u64 start, u64 end);
151
152int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
153 struct folio **in_folio_ret);
154
155int zlib_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
156 u64 start, struct folio **folios, unsigned long *out_folios,
157 unsigned long *total_in, unsigned long *total_out);
158int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
159int zlib_decompress(struct list_head *ws, const u8 *data_in,
160 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
161 size_t destlen);
162struct list_head *zlib_alloc_workspace(struct btrfs_fs_info *fs_info, unsigned int level);
163void zlib_free_workspace(struct list_head *ws);
164struct list_head *zlib_get_workspace(struct btrfs_fs_info *fs_info, unsigned int level);
165
166int lzo_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
167 u64 start, struct folio **folios, unsigned long *out_folios,
168 unsigned long *total_in, unsigned long *total_out);
169int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
170int lzo_decompress(struct list_head *ws, const u8 *data_in,
171 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
172 size_t destlen);
173struct list_head *lzo_alloc_workspace(struct btrfs_fs_info *fs_info);
174void lzo_free_workspace(struct list_head *ws);
175
176int zstd_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
177 u64 start, struct folio **folios, unsigned long *out_folios,
178 unsigned long *total_in, unsigned long *total_out);
179int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
180int zstd_decompress(struct list_head *ws, const u8 *data_in,
181 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
182 size_t destlen);
183int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info);
184void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info);
185struct list_head *zstd_alloc_workspace(struct btrfs_fs_info *fs_info, int level);
186void zstd_free_workspace(struct list_head *ws);
187struct list_head *zstd_get_workspace(struct btrfs_fs_info *fs_info, int level);
188void zstd_put_workspace(struct btrfs_fs_info *fs_info, struct list_head *ws);
189
190#endif