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 /* 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 37 #define BTRFS_ZLIB_DEFAULT_LEVEL 3 38 39 struct compressed_bio { 40 /* number of bios pending for this compressed extent */ 41 refcount_t pending_bios; 42 43 /* the pages with the compressed data on them */ 44 struct page **compressed_pages; 45 46 /* inode that owns this data */ 47 struct inode *inode; 48 49 /* starting offset in the inode for our pages */ 50 u64 start; 51 52 /* number of bytes in the inode we're working on */ 53 unsigned long len; 54 55 /* number of bytes on disk */ 56 unsigned long compressed_len; 57 58 /* the compression algorithm for this bio */ 59 int compress_type; 60 61 /* number of compressed pages in the array */ 62 unsigned long nr_pages; 63 64 /* IO errors */ 65 int errors; 66 int mirror_num; 67 68 /* for reads, this is the bio we are copying the data into */ 69 struct bio *orig_bio; 70 71 /* 72 * the start of a variable length array of checksums only 73 * used by reads 74 */ 75 u32 sums; 76 }; 77 78 void btrfs_init_compress(void); 79 void btrfs_exit_compress(void); 80 81 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 82 u64 start, struct page **pages, 83 unsigned long *out_pages, 84 unsigned long *total_in, 85 unsigned long *total_out); 86 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, 87 unsigned long start_byte, size_t srclen, size_t destlen); 88 int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, 89 unsigned long total_out, u64 disk_start, 90 struct bio *bio); 91 92 blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, 93 unsigned long len, u64 disk_start, 94 unsigned long compressed_len, 95 struct page **compressed_pages, 96 unsigned long nr_pages, 97 unsigned int write_flags); 98 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 99 int mirror_num, unsigned long bio_flags); 100 101 unsigned btrfs_compress_str2level(const char *str); 102 103 enum btrfs_compression_type { 104 BTRFS_COMPRESS_NONE = 0, 105 BTRFS_COMPRESS_ZLIB = 1, 106 BTRFS_COMPRESS_LZO = 2, 107 BTRFS_COMPRESS_ZSTD = 3, 108 BTRFS_COMPRESS_TYPES = 3, 109 }; 110 111 struct btrfs_compress_op { 112 struct list_head *(*alloc_workspace)(void); 113 114 void (*free_workspace)(struct list_head *workspace); 115 116 int (*compress_pages)(struct list_head *workspace, 117 struct address_space *mapping, 118 u64 start, 119 struct page **pages, 120 unsigned long *out_pages, 121 unsigned long *total_in, 122 unsigned long *total_out); 123 124 int (*decompress_bio)(struct list_head *workspace, 125 struct compressed_bio *cb); 126 127 int (*decompress)(struct list_head *workspace, 128 unsigned char *data_in, 129 struct page *dest_page, 130 unsigned long start_byte, 131 size_t srclen, size_t destlen); 132 133 void (*set_level)(struct list_head *ws, unsigned int type); 134 }; 135 136 extern const struct btrfs_compress_op btrfs_zlib_compress; 137 extern const struct btrfs_compress_op btrfs_lzo_compress; 138 extern const struct btrfs_compress_op btrfs_zstd_compress; 139 140 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); 141 142 #endif 143