compression.h

  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