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 #include <linux/mm.h>
  11 #include <linux/list.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/wait.h>
  14 #include "bio.h"
  15
  16 struct address_space;
  17 struct page;
  18 struct inode;
  19 struct btrfs_inode;
  20 struct btrfs_ordered_extent;
  21 struct btrfs_bio;
  22
  23 /*
  24  * We want to make sure that amount of RAM required to uncompress an extent is
  25  * reasonable, so we limit the total size in ram of a compressed extent to
  26  * 128k.  This is a crucial number because it also controls how easily we can
  27  * spread reads across cpus for decompression.
  28  *
  29  * We also want to make sure the amount of IO required to do a random read is
  30  * reasonably small, so we limit the size of a compressed extent to 128k.
  31  */
  32
  33 /* Maximum length of compressed data stored on disk */
  34 #define BTRFS_MAX_COMPRESSED            (SZ_128K)
  35 #define BTRFS_MAX_COMPRESSED_PAGES      (BTRFS_MAX_COMPRESSED / PAGE_SIZE)
  36 static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
  37
  38 /* Maximum size of data before compression */
  39 #define BTRFS_MAX_UNCOMPRESSED          (SZ_128K)
  40
  41 #define BTRFS_ZLIB_DEFAULT_LEVEL                3
  42
  43 struct compressed_bio {
  44         /* Number of compressed folios in the array. */
  45         unsigned int nr_folios;
  46
  47         /* The folios with the compressed data on them. */
  48         struct folio **compressed_folios;
  49
  50         /* starting offset in the inode for our pages */
  51         u64 start;
  52
  53         /* Number of bytes in the inode we're working on */
  54         unsigned int len;
  55
  56         /* Number of bytes on disk */
  57         unsigned int compressed_len;
  58
  59         /* The compression algorithm for this bio */
  60         u8 compress_type;
  61
  62         /* Whether this is a write for writeback. */
  63         bool writeback;
  64
  65         union {
  66                 /* For reads, this is the bio we are copying the data into */
  67                 struct btrfs_bio *orig_bbio;
  68                 struct work_struct write_end_work;
  69         };
  70
  71         /* Must be last. */
  72         struct btrfs_bio bbio;
  73 };
  74
  75 static inline unsigned int btrfs_compress_type(unsigned int type_level)
  76 {
  77         return (type_level & 0xF);
  78 }
  79
  80 static inline unsigned int btrfs_compress_level(unsigned int type_level)
  81 {
  82         return ((type_level & 0xF0) >> 4);
  83 }
  84
  85 /* @range_end must be exclusive. */
  86 static inline u32 btrfs_calc_input_length(u64 range_end, u64 cur)
  87 {
  88         u64 page_end = round_down(cur, PAGE_SIZE) + PAGE_SIZE;
  89
  90         return min(range_end, page_end) - cur;
  91 }
  92
  93 int __init btrfs_init_compress(void);
  94 void __cold btrfs_exit_compress(void);
  95
  96 int btrfs_compress_folios(unsigned int type_level, struct address_space *mapping,
  97                           u64 start, struct folio **folios, unsigned long *out_folios,
  98                          unsigned long *total_in, unsigned long *total_out);
  99 int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
 100                      unsigned long start_byte, size_t srclen, size_t destlen);
 101 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
 102                               struct compressed_bio *cb, u32 decompressed);
 103
 104 void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
 105                                    struct folio **compressed_folios,
 106                                    unsigned int nr_folios, blk_opf_t write_flags,
 107                                    bool writeback);
 108 void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
 109
 110 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
 111
 112 struct folio *btrfs_alloc_compr_folio(void);
 113 void btrfs_free_compr_folio(struct folio *folio);
 114
 115 enum btrfs_compression_type {
 116         BTRFS_COMPRESS_NONE  = 0,
 117         BTRFS_COMPRESS_ZLIB  = 1,
 118         BTRFS_COMPRESS_LZO   = 2,
 119         BTRFS_COMPRESS_ZSTD  = 3,
 120         BTRFS_NR_COMPRESS_TYPES = 4,
 121 };
 122
 123 struct workspace_manager {
 124         struct list_head idle_ws;
 125         spinlock_t ws_lock;
 126         /* Number of free workspaces */
 127         int free_ws;
 128         /* Total number of allocated workspaces */
 129         atomic_t total_ws;
 130         /* Waiters for a free workspace */
 131         wait_queue_head_t ws_wait;
 132 };
 133
 134 struct list_head *btrfs_get_workspace(int type, unsigned int level);
 135 void btrfs_put_workspace(int type, struct list_head *ws);
 136
 137 struct btrfs_compress_op {
 138         struct workspace_manager *workspace_manager;
 139         /* Maximum level supported by the compression algorithm */
 140         unsigned int max_level;
 141         unsigned int default_level;
 142 };
 143
 144 /* The heuristic workspaces are managed via the 0th workspace manager */
 145 #define BTRFS_NR_WORKSPACE_MANAGERS     BTRFS_NR_COMPRESS_TYPES
 146
 147 extern const struct btrfs_compress_op btrfs_heuristic_compress;
 148 extern const struct btrfs_compress_op btrfs_zlib_compress;
 149 extern const struct btrfs_compress_op btrfs_lzo_compress;
 150 extern const struct btrfs_compress_op btrfs_zstd_compress;
 151
 152 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
 153 bool btrfs_compress_is_valid_type(const char *str, size_t len);
 154
 155 int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end);
 156
 157 int btrfs_compress_filemap_get_folio(struct address_space *mapping, u64 start,
 158                                      struct folio **in_folio_ret);
 159
 160 int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
 161                          u64 start, struct folio **folios, unsigned long *out_folios,
 162                 unsigned long *total_in, unsigned long *total_out);
 163 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 164 int zlib_decompress(struct list_head *ws, const u8 *data_in,
 165                 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
 166                 size_t destlen);
 167 struct list_head *zlib_alloc_workspace(unsigned int level);
 168 void zlib_free_workspace(struct list_head *ws);
 169 struct list_head *zlib_get_workspace(unsigned int level);
 170
 171 int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
 172                         u64 start, struct folio **folios, unsigned long *out_folios,
 173                 unsigned long *total_in, unsigned long *total_out);
 174 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 175 int lzo_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);
 178 struct list_head *lzo_alloc_workspace(void);
 179 void lzo_free_workspace(struct list_head *ws);
 180
 181 int zstd_compress_folios(struct list_head *ws, struct address_space *mapping,
 182                          u64 start, struct folio **folios, unsigned long *out_folios,
 183                 unsigned long *total_in, unsigned long *total_out);
 184 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 185 int zstd_decompress(struct list_head *ws, const u8 *data_in,
 186                 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
 187                 size_t destlen);
 188 void zstd_init_workspace_manager(void);
 189 void zstd_cleanup_workspace_manager(void);
 190 struct list_head *zstd_alloc_workspace(unsigned int level);
 191 void zstd_free_workspace(struct list_head *ws);
 192 struct list_head *zstd_get_workspace(unsigned int level);
 193 void zstd_put_workspace(struct list_head *ws);
 194
 195 #endif