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c8b97818 CM |
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 | ||
ff763866 DS |
22 | /* |
23 | * We want to make sure that amount of RAM required to uncompress an extent is | |
24 | * reasonable, so we limit the total size in ram of a compressed extent to | |
25 | * 128k. This is a crucial number because it also controls how easily we can | |
26 | * spread reads across cpus for decompression. | |
27 | * | |
28 | * We also want to make sure the amount of IO required to do a random read is | |
29 | * reasonably small, so we limit the size of a compressed extent to 128k. | |
30 | */ | |
31 | ||
32 | /* Maximum length of compressed data stored on disk */ | |
33 | #define BTRFS_MAX_COMPRESSED (SZ_128K) | |
34 | /* Maximum size of data before compression */ | |
35 | #define BTRFS_MAX_UNCOMPRESSED (SZ_128K) | |
36 | ||
143bede5 | 37 | void btrfs_init_compress(void); |
261507a0 LZ |
38 | void btrfs_exit_compress(void); |
39 | ||
40 | int btrfs_compress_pages(int type, struct address_space *mapping, | |
38c31464 | 41 | u64 start, struct page **pages, |
261507a0 LZ |
42 | unsigned long *out_pages, |
43 | unsigned long *total_in, | |
e5d74902 | 44 | unsigned long *total_out); |
261507a0 LZ |
45 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, |
46 | unsigned long start_byte, size_t srclen, size_t destlen); | |
14a3357b | 47 | int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, |
3a39c18d | 48 | unsigned long total_out, u64 disk_start, |
974b1adc | 49 | struct bio *bio); |
261507a0 | 50 | |
c8b97818 CM |
51 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, |
52 | unsigned long len, u64 disk_start, | |
53 | unsigned long compressed_len, | |
54 | struct page **compressed_pages, | |
55 | unsigned long nr_pages); | |
56 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
57 | int mirror_num, unsigned long bio_flags); | |
ebb8765b AJ |
58 | |
59 | enum btrfs_compression_type { | |
60 | BTRFS_COMPRESS_NONE = 0, | |
61 | BTRFS_COMPRESS_ZLIB = 1, | |
62 | BTRFS_COMPRESS_LZO = 2, | |
63 | BTRFS_COMPRESS_TYPES = 2, | |
64 | BTRFS_COMPRESS_LAST = 3, | |
65 | }; | |
66 | ||
261507a0 LZ |
67 | struct btrfs_compress_op { |
68 | struct list_head *(*alloc_workspace)(void); | |
69 | ||
70 | void (*free_workspace)(struct list_head *workspace); | |
71 | ||
72 | int (*compress_pages)(struct list_head *workspace, | |
73 | struct address_space *mapping, | |
38c31464 | 74 | u64 start, |
261507a0 | 75 | struct page **pages, |
261507a0 LZ |
76 | unsigned long *out_pages, |
77 | unsigned long *total_in, | |
e5d74902 | 78 | unsigned long *total_out); |
261507a0 | 79 | |
974b1adc | 80 | int (*decompress_bio)(struct list_head *workspace, |
261507a0 LZ |
81 | struct page **pages_in, |
82 | u64 disk_start, | |
974b1adc | 83 | struct bio *orig_bio, |
261507a0 LZ |
84 | size_t srclen); |
85 | ||
86 | int (*decompress)(struct list_head *workspace, | |
87 | unsigned char *data_in, | |
88 | struct page *dest_page, | |
89 | unsigned long start_byte, | |
90 | size_t srclen, size_t destlen); | |
91 | }; | |
92 | ||
e8c9f186 DS |
93 | extern const struct btrfs_compress_op btrfs_zlib_compress; |
94 | extern const struct btrfs_compress_op btrfs_lzo_compress; | |
261507a0 | 95 | |
c8b97818 | 96 | #endif |