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
19struct address_space;
20struct inode;
21struct btrfs_inode;
22struct 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)
37static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
38
39/* Maximum size of data before compression */
40#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
41
42#define BTRFS_ZLIB_DEFAULT_LEVEL 3
43
44struct compressed_bio {
45 /* Number of compressed folios in the array. */
46 unsigned int nr_folios;
47
48 /* The folios with the compressed data on them. */
49 struct folio **compressed_folios;
50
51 /* starting offset in the inode for our pages */
52 u64 start;
53
54 /* Number of bytes in the inode we're working on */
55 unsigned int len;
56
57 /* Number of bytes on disk */
58 unsigned int compressed_len;
59
60 /* The compression algorithm for this bio */
61 u8 compress_type;
62
63 /* Whether this is a write for writeback. */
64 bool writeback;
65
66 /* For reads, this is the bio we are copying the data into. */
67 struct btrfs_bio *orig_bbio;
68
69 /* Must be last. */
70 struct btrfs_bio bbio;
71};
72
73static inline struct btrfs_fs_info *cb_to_fs_info(const struct compressed_bio *cb)
74{
75 return cb->bbio.inode->root->fs_info;
76}
77
78/* @range_end must be exclusive. */
79static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u64 cur)
80{
81 /* @cur must be inside the folio. */
82 ASSERT(folio_pos(folio) <= cur);
83 ASSERT(cur < folio_next_pos(folio));
84 return umin(range_end, folio_next_pos(folio)) - cur;
85}
86
87int btrfs_alloc_compress_wsm(struct btrfs_fs_info *fs_info);
88void btrfs_free_compress_wsm(struct btrfs_fs_info *fs_info);
89
90int __init btrfs_init_compress(void);
91void __cold btrfs_exit_compress(void);
92
93bool btrfs_compress_level_valid(unsigned int type, int level);
94int btrfs_compress_folios(unsigned int type, int level, struct btrfs_inode *inode,
95 u64 start, struct folio **folios, unsigned long *out_folios,
96 unsigned long *total_in, unsigned long *total_out);
97int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
98 unsigned long dest_pgoff, size_t srclen, size_t destlen);
99int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
100 struct compressed_bio *cb, u32 decompressed);
101
102void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
103 struct folio **compressed_folios,
104 unsigned int nr_folios, blk_opf_t write_flags,
105 bool writeback);
106void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
107
108int btrfs_compress_str2level(unsigned int type, const char *str, int *level_ret);
109
110struct folio *btrfs_alloc_compr_folio(struct btrfs_fs_info *fs_info);
111void btrfs_free_compr_folio(struct folio *folio);
112
113struct workspace_manager {
114 struct list_head idle_ws;
115 spinlock_t ws_lock;
116 /* Number of free workspaces */
117 int free_ws;
118 /* Total number of allocated workspaces */
119 atomic_t total_ws;
120 /* Waiters for a free workspace */
121 wait_queue_head_t ws_wait;
122};
123
124struct list_head *btrfs_get_workspace(struct btrfs_fs_info *fs_info, int type, int level);
125void btrfs_put_workspace(struct btrfs_fs_info *fs_info, int type, struct list_head *ws);
126
127struct btrfs_compress_levels {
128 /* Maximum level supported by the compression algorithm */
129 int min_level;
130 int max_level;
131 int default_level;
132};
133
134/* The heuristic workspaces are managed via the 0th workspace manager */
135#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
136
137extern const struct btrfs_compress_levels btrfs_heuristic_compress;
138extern const struct btrfs_compress_levels btrfs_zlib_compress;
139extern const struct btrfs_compress_levels btrfs_lzo_compress;
140extern const struct btrfs_compress_levels btrfs_zstd_compress;
141
142const char* btrfs_compress_type2str(enum btrfs_compression_type type);
143bool btrfs_compress_is_valid_type(const char *str, size_t len);
144
145int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
146
147int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
148 struct folio **in_folio_ret);
149
150int zlib_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
151 u64 start, struct folio **folios, unsigned long *out_folios,
152 unsigned long *total_in, unsigned long *total_out);
153int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
154int zlib_decompress(struct list_head *ws, const u8 *data_in,
155 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
156 size_t destlen);
157struct list_head *zlib_alloc_workspace(struct btrfs_fs_info *fs_info, unsigned int level);
158void zlib_free_workspace(struct list_head *ws);
159struct list_head *zlib_get_workspace(struct btrfs_fs_info *fs_info, unsigned int level);
160
161int lzo_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
162 u64 start, struct folio **folios, unsigned long *out_folios,
163 unsigned long *total_in, unsigned long *total_out);
164int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
165int 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);
168struct list_head *lzo_alloc_workspace(struct btrfs_fs_info *fs_info);
169void lzo_free_workspace(struct list_head *ws);
170
171int zstd_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
172 u64 start, struct folio **folios, unsigned long *out_folios,
173 unsigned long *total_in, unsigned long *total_out);
174int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
175int zstd_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);
178int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info);
179void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info);
180struct list_head *zstd_alloc_workspace(struct btrfs_fs_info *fs_info, int level);
181void zstd_free_workspace(struct list_head *ws);
182struct list_head *zstd_get_workspace(struct btrfs_fs_info *fs_info, int level);
183void zstd_put_workspace(struct btrfs_fs_info *fs_info, struct list_head *ws);
184
185#endif
186

source code of linux/fs/btrfs/compression.h