LXR linux/fs/btrfs/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
  11struct btrfs_inode;
  12
  13/*
  14 * We want to make sure that amount of RAM required to uncompress an extent is
  15 * reasonable, so we limit the total size in ram of a compressed extent to
  16 * 128k.  This is a crucial number because it also controls how easily we can
  17 * spread reads across cpus for decompression.
  18 *
  19 * We also want to make sure the amount of IO required to do a random read is
  20 * reasonably small, so we limit the size of a compressed extent to 128k.
  21 */
  22
  23/* Maximum length of compressed data stored on disk */
  24#define BTRFS_MAX_COMPRESSED            (SZ_128K)
  25/* Maximum size of data before compression */
  26#define BTRFS_MAX_UNCOMPRESSED          (SZ_128K)
  27
  28#define BTRFS_ZLIB_DEFAULT_LEVEL                3
  29
  30struct compressed_bio {
  31        /* number of bios pending for this compressed extent */
  32        refcount_t pending_bios;
  33
  34        /* Number of compressed pages in the array */
  35        unsigned int nr_pages;
  36
  37        /* the pages with the compressed data on them */
  38        struct page **compressed_pages;
  39
  40        /* inode that owns this data */
  41        struct inode *inode;
  42
  43        /* starting offset in the inode for our pages */
  44        u64 start;
  45
  46        /* Number of bytes in the inode we're working on */
  47        unsigned int len;
  48
  49        /* Number of bytes on disk */
  50        unsigned int compressed_len;
  51
  52        /* The compression algorithm for this bio */
  53        u8 compress_type;
  54
  55        /* IO errors */
  56        u8 errors;
  57        int mirror_num;
  58
  59        /* for reads, this is the bio we are copying the data into */
  60        struct bio *orig_bio;
  61
  62        /*
  63         * the start of a variable length array of checksums only
  64         * used by reads
  65         */
  66        u8 sums[];
  67};
  68
  69static inline unsigned int btrfs_compress_type(unsigned int type_level)
  70{
  71        return (type_level & 0xF);
  72}
  73
  74static inline unsigned int btrfs_compress_level(unsigned int type_level)
  75{
  76        return ((type_level & 0xF0) >> 4);
  77}
  78
  79void __init btrfs_init_compress(void);
  80void __cold btrfs_exit_compress(void);
  81
  82int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
  83                         u64 start, struct page **pages,
  84                         unsigned long *out_pages,
  85                         unsigned long *total_in,
  86                         unsigned long *total_out);
  87int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
  88                     unsigned long start_byte, size_t srclen, size_t destlen);
  89int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
  90                              struct compressed_bio *cb, u32 decompressed);
  91
  92blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
  93                                  unsigned int len, u64 disk_start,
  94                                  unsigned int compressed_len,
  95                                  struct page **compressed_pages,
  96                                  unsigned int nr_pages,
  97                                  unsigned int write_flags,
  98                                  struct cgroup_subsys_state *blkcg_css);
  99blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 100                                 int mirror_num, unsigned long bio_flags);
 101
 102unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
 103
 104enum btrfs_compression_type {
 105        BTRFS_COMPRESS_NONE  = 0,
 106        BTRFS_COMPRESS_ZLIB  = 1,
 107        BTRFS_COMPRESS_LZO   = 2,
 108        BTRFS_COMPRESS_ZSTD  = 3,
 109        BTRFS_NR_COMPRESS_TYPES = 4,
 110};
 111
 112struct workspace_manager {
 113        struct list_head idle_ws;
 114        spinlock_t ws_lock;
 115        /* Number of free workspaces */
 116        int free_ws;
 117        /* Total number of allocated workspaces */
 118        atomic_t total_ws;
 119        /* Waiters for a free workspace */
 120        wait_queue_head_t ws_wait;
 121};
 122
 123struct list_head *btrfs_get_workspace(int type, unsigned int level);
 124void btrfs_put_workspace(int type, struct list_head *ws);
 125
 126struct btrfs_compress_op {
 127        struct workspace_manager *workspace_manager;
 128        /* Maximum level supported by the compression algorithm */
 129        unsigned int max_level;
 130        unsigned int default_level;
 131};
 132
 133/* The heuristic workspaces are managed via the 0th workspace manager */
 134#define BTRFS_NR_WORKSPACE_MANAGERS     BTRFS_NR_COMPRESS_TYPES
 135
 136extern const struct btrfs_compress_op btrfs_heuristic_compress;
 137extern const struct btrfs_compress_op btrfs_zlib_compress;
 138extern const struct btrfs_compress_op btrfs_lzo_compress;
 139extern const struct btrfs_compress_op btrfs_zstd_compress;
 140
 141const char* btrfs_compress_type2str(enum btrfs_compression_type type);
 142bool btrfs_compress_is_valid_type(const char *str, size_t len);
 143
 144int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
 145
 146int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 147                u64 start, struct page **pages, unsigned long *out_pages,
 148                unsigned long *total_in, unsigned long *total_out);
 149int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 150int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 151                struct page *dest_page, unsigned long start_byte, size_t srclen,
 152                size_t destlen);
 153struct list_head *zlib_alloc_workspace(unsigned int level);
 154void zlib_free_workspace(struct list_head *ws);
 155struct list_head *zlib_get_workspace(unsigned int level);
 156
 157int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 158                u64 start, struct page **pages, unsigned long *out_pages,
 159                unsigned long *total_in, unsigned long *total_out);
 160int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 161int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 162                struct page *dest_page, unsigned long start_byte, size_t srclen,
 163                size_t destlen);
 164struct list_head *lzo_alloc_workspace(unsigned int level);
 165void lzo_free_workspace(struct list_head *ws);
 166
 167int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
 168                u64 start, struct page **pages, unsigned long *out_pages,
 169                unsigned long *total_in, unsigned long *total_out);
 170int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 171int zstd_decompress(struct list_head *ws, unsigned char *data_in,
 172                struct page *dest_page, unsigned long start_byte, size_t srclen,
 173                size_t destlen);
 174void zstd_init_workspace_manager(void);
 175void zstd_cleanup_workspace_manager(void);
 176struct list_head *zstd_alloc_workspace(unsigned int level);
 177void zstd_free_workspace(struct list_head *ws);
 178struct list_head *zstd_get_workspace(unsigned int level);
 179void zstd_put_workspace(struct list_head *ws);
 180
 181#endif
 182