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
  22 void btrfs_init_compress(void);
  23 void btrfs_exit_compress(void);
  24
  25 int 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);
  33 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
  34                      unsigned long start_byte, size_t srclen, size_t destlen);
  35 int 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
  41 int 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);
  46 int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
  47                                  int mirror_num, unsigned long bio_flags);
  48 void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
  49                                    unsigned long pg_index,
  50                                    unsigned long pg_offset);
  51
  52 enum 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
  60 struct 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
  89 extern const struct btrfs_compress_op btrfs_zlib_compress;
  90 extern const struct btrfs_compress_op btrfs_lzo_compress;
  91
  92 #endif