[linux-block.git] / fs / btrfs / compression.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 */

#ifndef BTRFS_COMPRESSION_H
#define BTRFS_COMPRESSION_H

#include <linux/sizes.h>

/*
 * We want to make sure that amount of RAM required to uncompress an extent is
 * reasonable, so we limit the total size in ram of a compressed extent to
 * 128k.  This is a crucial number because it also controls how easily we can
 * spread reads across cpus for decompression.
 *
 * We also want to make sure the amount of IO required to do a random read is
 * reasonably small, so we limit the size of a compressed extent to 128k.
 */

/* Maximum length of compressed data stored on disk */
#define BTRFS_MAX_COMPRESSED		(SZ_128K)
/* Maximum size of data before compression */
#define BTRFS_MAX_UNCOMPRESSED		(SZ_128K)

#define	BTRFS_ZLIB_DEFAULT_LEVEL		3

struct compressed_bio {
	/* number of bios pending for this compressed extent */
	refcount_t pending_bios;

	/* the pages with the compressed data on them */
	struct page **compressed_pages;

	/* inode that owns this data */
	struct inode *inode;

	/* starting offset in the inode for our pages */
	u64 start;

	/* number of bytes in the inode we're working on */
	unsigned long len;

	/* number of bytes on disk */
	unsigned long compressed_len;

	/* the compression algorithm for this bio */
	int compress_type;

	/* number of compressed pages in the array */
	unsigned long nr_pages;

	/* IO errors */
	int errors;
	int mirror_num;

	/* for reads, this is the bio we are copying the data into */
	struct bio *orig_bio;

	/*
	 * the start of a variable length array of checksums only
	 * used by reads
	 */
	u32 sums;
};

void __init btrfs_init_compress(void);
void __cold btrfs_exit_compress(void);

int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
			 u64 start, struct page **pages,
			 unsigned long *out_pages,
			 unsigned long *total_in,
			 unsigned long *total_out);
int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
		     unsigned long start_byte, size_t srclen, size_t destlen);
int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
			      unsigned long total_out, u64 disk_start,
			      struct bio *bio);

blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
				  unsigned long len, u64 disk_start,
				  unsigned long compressed_len,
				  struct page **compressed_pages,
				  unsigned long nr_pages,
				  unsigned int write_flags);
blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
				 int mirror_num, unsigned long bio_flags);

unsigned btrfs_compress_str2level(const char *str);

enum btrfs_compression_type {
	BTRFS_COMPRESS_NONE  = 0,
	BTRFS_COMPRESS_ZLIB  = 1,
	BTRFS_COMPRESS_LZO   = 2,
	BTRFS_COMPRESS_ZSTD  = 3,
	BTRFS_COMPRESS_TYPES = 3,
};

struct btrfs_compress_op {
	struct list_head *(*alloc_workspace)(void);

	void (*free_workspace)(struct list_head *workspace);

	int (*compress_pages)(struct list_head *workspace,
			      struct address_space *mapping,
			      u64 start,
			      struct page **pages,
			      unsigned long *out_pages,
			      unsigned long *total_in,
			      unsigned long *total_out);

	int (*decompress_bio)(struct list_head *workspace,
				struct compressed_bio *cb);

	int (*decompress)(struct list_head *workspace,
			  unsigned char *data_in,
			  struct page *dest_page,
			  unsigned long start_byte,
			  size_t srclen, size_t destlen);

	void (*set_level)(struct list_head *ws, unsigned int type);
};

extern const struct btrfs_compress_op btrfs_zlib_compress;
extern const struct btrfs_compress_op btrfs_lzo_compress;
extern const struct btrfs_compress_op btrfs_zstd_compress;

const char* btrfs_compress_type2str(enum btrfs_compression_type type);

int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);

#endif
Commit	Line	Data
	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
	11	/*
	12	* We want to make sure that amount of RAM required to uncompress an extent is
	13	* reasonable, so we limit the total size in ram of a compressed extent to
	14	* 128k. This is a crucial number because it also controls how easily we can
	15	* spread reads across cpus for decompression.
	16	*
	17	* We also want to make sure the amount of IO required to do a random read is
	18	* reasonably small, so we limit the size of a compressed extent to 128k.
	19	*/
	20
	21	/* Maximum length of compressed data stored on disk */
	22	#define BTRFS_MAX_COMPRESSED (SZ_128K)
	23	/* Maximum size of data before compression */
	24	#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
	25
	26	#define BTRFS_ZLIB_DEFAULT_LEVEL 3
	27
	28	struct compressed_bio {
	29	/* number of bios pending for this compressed extent */
	30	refcount_t pending_bios;
	31
	32	/* the pages with the compressed data on them */
	33	struct page **compressed_pages;
	34
	35	/* inode that owns this data */
	36	struct inode *inode;
	37
	38	/* starting offset in the inode for our pages */
	39	u64 start;
	40
	41	/* number of bytes in the inode we're working on */
	42	unsigned long len;
	43
	44	/* number of bytes on disk */
	45	unsigned long compressed_len;
	46
	47	/* the compression algorithm for this bio */
	48	int compress_type;
	49
	50	/* number of compressed pages in the array */
	51	unsigned long nr_pages;
	52
	53	/* IO errors */
	54	int errors;
	55	int mirror_num;
	56
	57	/* for reads, this is the bio we are copying the data into */
	58	struct bio *orig_bio;
	59
	60	/*
	61	* the start of a variable length array of checksums only
	62	* used by reads
	63	*/
	64	u32 sums;
	65	};
	66
	67	void __init btrfs_init_compress(void);
	68	void __cold btrfs_exit_compress(void);
	69
	70	int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
	71	u64 start, struct page **pages,
	72	unsigned long *out_pages,
	73	unsigned long *total_in,
	74	unsigned long *total_out);
	75	int btrfs_decompress(int type, unsigned char data_in, struct page dest_page,
	76	unsigned long start_byte, size_t srclen, size_t destlen);
	77	int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
	78	unsigned long total_out, u64 disk_start,
	79	struct bio *bio);
	80
	81	blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
	82	unsigned long len, u64 disk_start,
	83	unsigned long compressed_len,
	84	struct page **compressed_pages,
	85	unsigned long nr_pages,
	86	unsigned int write_flags);
	87	blk_status_t btrfs_submit_compressed_read(struct inode inode, struct bio bio,
	88	int mirror_num, unsigned long bio_flags);
	89
	90	unsigned btrfs_compress_str2level(const char *str);
	91
	92	enum btrfs_compression_type {
	93	BTRFS_COMPRESS_NONE = 0,
	94	BTRFS_COMPRESS_ZLIB = 1,
	95	BTRFS_COMPRESS_LZO = 2,
	96	BTRFS_COMPRESS_ZSTD = 3,
	97	BTRFS_COMPRESS_TYPES = 3,
	98	};
	99
	100	struct btrfs_compress_op {
	101	struct list_head (alloc_workspace)(void);
	102
	103	void (free_workspace)(struct list_head workspace);
	104
	105	int (compress_pages)(struct list_head workspace,
	106	struct address_space *mapping,
	107	u64 start,
	108	struct page **pages,
	109	unsigned long *out_pages,
	110	unsigned long *total_in,
	111	unsigned long *total_out);
	112
	113	int (decompress_bio)(struct list_head workspace,
	114	struct compressed_bio *cb);
	115
	116	int (decompress)(struct list_head workspace,
	117	unsigned char *data_in,
	118	struct page *dest_page,
	119	unsigned long start_byte,
	120	size_t srclen, size_t destlen);
	121
	122	void (set_level)(struct list_head ws, unsigned int type);
	123	};
	124
	125	extern const struct btrfs_compress_op btrfs_zlib_compress;
	126	extern const struct btrfs_compress_op btrfs_lzo_compress;
	127	extern const struct btrfs_compress_op btrfs_zstd_compress;
	128
	129	const char* btrfs_compress_type2str(enum btrfs_compression_type type);
	130
	131	int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
	132
	133	#endif