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)
  25static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
  26
  27/* Maximum size of data before compression */
  28#define BTRFS_MAX_UNCOMPRESSED          (SZ_128K)
  29
  30#define BTRFS_ZLIB_DEFAULT_LEVEL                3
  31
  32struct compressed_bio {
  33        /* Number of sectors with unfinished IO (unsubmitted or unfinished) */
  34        refcount_t pending_sectors;
  35
  36        /* Number of compressed pages in the array */
  37        unsigned int nr_pages;
  38
  39        /* the pages with the compressed data on them */
  40        struct page **compressed_pages;
  41
  42        /* inode that owns this data */
  43        struct inode *inode;
  44
  45        /* starting offset in the inode for our pages */
  46        u64 start;
  47
  48        /* Number of bytes in the inode we're working on */
  49        unsigned int len;
  50
  51        /* Number of bytes on disk */
  52        unsigned int compressed_len;
  53
  54        /* The compression algorithm for this bio */
  55        u8 compress_type;
  56
  57        /* Whether this is a write for writeback. */
  58        bool writeback;
  59
  60        /* IO errors */
  61        blk_status_t status;
  62        int mirror_num;
  63
  64        /* for reads, this is the bio we are copying the data into */
  65        struct bio *orig_bio;
  66
  67        /*
  68         * the start of a variable length array of checksums only
  69         * used by reads
  70         */
  71        u8 sums[];
  72};
  73
  74static inline unsigned int btrfs_compress_type(unsigned int type_level)
  75{
  76        return (type_level & 0xF);
  77}
  78
  79static inline unsigned int btrfs_compress_level(unsigned int type_level)
  80{
  81        return ((type_level & 0xF0) >> 4);
  82}
  83
  84void __init btrfs_init_compress(void);
  85void __cold btrfs_exit_compress(void);
  86
  87int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
  88                         u64 start, struct page **pages,
  89                         unsigned long *out_pages,
  90                         unsigned long *total_in,
  91                         unsigned long *total_out);
  92int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
  93                     unsigned long start_byte, size_t srclen, size_t destlen);
  94int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
  95                              struct compressed_bio *cb, u32 decompressed);
  96
  97blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
  98                                  unsigned int len, u64 disk_start,
  99                                  unsigned int compressed_len,
 100                                  struct page **compressed_pages,
 101                                  unsigned int nr_pages,
 102                                  unsigned int write_flags,
 103                                  struct cgroup_subsys_state *blkcg_css,
 104                                  bool writeback);
 105void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 106                                  int mirror_num);
 107
 108unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
 109
 110enum btrfs_compression_type {
 111        BTRFS_COMPRESS_NONE  = 0,
 112        BTRFS_COMPRESS_ZLIB  = 1,
 113        BTRFS_COMPRESS_LZO   = 2,
 114        BTRFS_COMPRESS_ZSTD  = 3,
 115        BTRFS_NR_COMPRESS_TYPES = 4,
 116};
 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(int type, unsigned int level);
 130void btrfs_put_workspace(int type, struct list_head *ws);
 131
 132struct btrfs_compress_op {
 133        struct workspace_manager *workspace_manager;
 134        /* Maximum level supported by the compression algorithm */
 135        unsigned int max_level;
 136        unsigned 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_op btrfs_heuristic_compress;
 143extern const struct btrfs_compress_op btrfs_zlib_compress;
 144extern const struct btrfs_compress_op btrfs_lzo_compress;
 145extern const struct btrfs_compress_op 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 inode *inode, u64 start, u64 end);
 151
 152int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 153                u64 start, struct page **pages, unsigned long *out_pages,
 154                unsigned long *total_in, unsigned long *total_out);
 155int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 156int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 157                struct page *dest_page, unsigned long start_byte, size_t srclen,
 158                size_t destlen);
 159struct list_head *zlib_alloc_workspace(unsigned int level);
 160void zlib_free_workspace(struct list_head *ws);
 161struct list_head *zlib_get_workspace(unsigned int level);
 162
 163int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 164                u64 start, struct page **pages, unsigned long *out_pages,
 165                unsigned long *total_in, unsigned long *total_out);
 166int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 167int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 168                struct page *dest_page, unsigned long start_byte, size_t srclen,
 169                size_t destlen);
 170struct list_head *lzo_alloc_workspace(unsigned int level);
 171void lzo_free_workspace(struct list_head *ws);
 172
 173int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
 174                u64 start, struct page **pages, unsigned long *out_pages,
 175                unsigned long *total_in, unsigned long *total_out);
 176int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 177int zstd_decompress(struct list_head *ws, unsigned char *data_in,
 178                struct page *dest_page, unsigned long start_byte, size_t srclen,
 179                size_t destlen);
 180void zstd_init_workspace_manager(void);
 181void zstd_cleanup_workspace_manager(void);
 182struct list_head *zstd_alloc_workspace(unsigned int level);
 183void zstd_free_workspace(struct list_head *ws);
 184struct list_head *zstd_get_workspace(unsigned int level);
 185void zstd_put_workspace(struct list_head *ws);
 186
 187#endif
 188