LXR linux/fs/btrfs/compression.h

   1/*
   2 * Copyright (C) 2008 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#ifndef __BTRFS_COMPRESSION_
  20#define __BTRFS_COMPRESSION_
  21
  22void btrfs_init_compress(void);
  23void btrfs_exit_compress(void);
  24
  25int btrfs_compress_pages(int type, struct address_space *mapping,
  26                         u64 start, unsigned long len,
  27                         struct page **pages,
  28                         unsigned long nr_dest_pages,
  29                         unsigned long *out_pages,
  30                         unsigned long *total_in,
  31                         unsigned long *total_out,
  32                         unsigned long max_out);
  33int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
  34                     unsigned long start_byte, size_t srclen, size_t destlen);
  35int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
  36                              unsigned long total_out, u64 disk_start,
  37                              struct bio_vec *bvec, int vcnt,
  38                              unsigned long *pg_index,
  39                              unsigned long *pg_offset);
  40
  41int btrfs_submit_compressed_write(struct inode *inode, u64 start,
  42                                  unsigned long len, u64 disk_start,
  43                                  unsigned long compressed_len,
  44                                  struct page **compressed_pages,
  45                                  unsigned long nr_pages);
  46int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
  47                                 int mirror_num, unsigned long bio_flags);
  48void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
  49                                   unsigned long pg_index,
  50                                   unsigned long pg_offset);
  51
  52enum btrfs_compression_type {
  53        BTRFS_COMPRESS_NONE  = 0,
  54        BTRFS_COMPRESS_ZLIB  = 1,
  55        BTRFS_COMPRESS_LZO   = 2,
  56        BTRFS_COMPRESS_TYPES = 2,
  57        BTRFS_COMPRESS_LAST  = 3,
  58};
  59
  60struct btrfs_compress_op {
  61        struct list_head *(*alloc_workspace)(void);
  62
  63        void (*free_workspace)(struct list_head *workspace);
  64
  65        int (*compress_pages)(struct list_head *workspace,
  66                              struct address_space *mapping,
  67                              u64 start, unsigned long len,
  68                              struct page **pages,
  69                              unsigned long nr_dest_pages,
  70                              unsigned long *out_pages,
  71                              unsigned long *total_in,
  72                              unsigned long *total_out,
  73                              unsigned long max_out);
  74
  75        int (*decompress_biovec)(struct list_head *workspace,
  76                                 struct page **pages_in,
  77                                 u64 disk_start,
  78                                 struct bio_vec *bvec,
  79                                 int vcnt,
  80                                 size_t srclen);
  81
  82        int (*decompress)(struct list_head *workspace,
  83                          unsigned char *data_in,
  84                          struct page *dest_page,
  85                          unsigned long start_byte,
  86                          size_t srclen, size_t destlen);
  87};
  88
  89extern const struct btrfs_compress_op btrfs_zlib_compress;
  90extern const struct btrfs_compress_op btrfs_lzo_compress;
  91
  92#endif
  93