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 11 /* 12 * We want to make sure that amount of RAM required to uncompress an extent is 13 * reasonable, so we limit the total size in ram of a compressed extent to 14 * 128k. This is a crucial number because it also controls how easily we can 15 * spread reads across cpus for decompression. 16 * 17 * We also want to make sure the amount of IO required to do a random read is 18 * reasonably small, so we limit the size of a compressed extent to 128k. 19 */ 20 21 /* Maximum length of compressed data stored on disk */ 22 #define BTRFS_MAX_COMPRESSED (SZ_128K) 23 /* Maximum size of data before compression */ 24 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K) 25 26 #define BTRFS_ZLIB_DEFAULT_LEVEL 3 27 28 struct compressed_bio { 29 /* number of bios pending for this compressed extent */ 30 refcount_t pending_bios; 31 32 /* the pages with the compressed data on them */ 33 struct page **compressed_pages; 34 35 /* inode that owns this data */ 36 struct inode *inode; 37 38 /* starting offset in the inode for our pages */ 39 u64 start; 40 41 /* number of bytes in the inode we're working on */ 42 unsigned long len; 43 44 /* number of bytes on disk */ 45 unsigned long compressed_len; 46 47 /* the compression algorithm for this bio */ 48 int compress_type; 49 50 /* number of compressed pages in the array */ 51 unsigned long nr_pages; 52 53 /* IO errors */ 54 int errors; 55 int mirror_num; 56 57 /* for reads, this is the bio we are copying the data into */ 58 struct bio *orig_bio; 59 60 /* 61 * the start of a variable length array of checksums only 62 * used by reads 63 */ 64 u32 sums; 65 }; 66 67 void __init btrfs_init_compress(void); 68 void __cold btrfs_exit_compress(void); 69 70 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 71 u64 start, struct page **pages, 72 unsigned long *out_pages, 73 unsigned long *total_in, 74 unsigned long *total_out); 75 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, 76 unsigned long start_byte, size_t srclen, size_t destlen); 77 int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, 78 unsigned long total_out, u64 disk_start, 79 struct bio *bio); 80 81 blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, 82 unsigned long len, u64 disk_start, 83 unsigned long compressed_len, 84 struct page **compressed_pages, 85 unsigned long nr_pages, 86 unsigned int write_flags); 87 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 88 int mirror_num, unsigned long bio_flags); 89 90 unsigned btrfs_compress_str2level(const char *str); 91 92 enum btrfs_compression_type { 93 BTRFS_COMPRESS_NONE = 0, 94 BTRFS_COMPRESS_ZLIB = 1, 95 BTRFS_COMPRESS_LZO = 2, 96 BTRFS_COMPRESS_ZSTD = 3, 97 BTRFS_COMPRESS_TYPES = 3, 98 }; 99 100 struct btrfs_compress_op { 101 struct list_head *(*alloc_workspace)(void); 102 103 void (*free_workspace)(struct list_head *workspace); 104 105 int (*compress_pages)(struct list_head *workspace, 106 struct address_space *mapping, 107 u64 start, 108 struct page **pages, 109 unsigned long *out_pages, 110 unsigned long *total_in, 111 unsigned long *total_out); 112 113 int (*decompress_bio)(struct list_head *workspace, 114 struct compressed_bio *cb); 115 116 int (*decompress)(struct list_head *workspace, 117 unsigned char *data_in, 118 struct page *dest_page, 119 unsigned long start_byte, 120 size_t srclen, size_t destlen); 121 122 void (*set_level)(struct list_head *ws, unsigned int type); 123 }; 124 125 extern const struct btrfs_compress_op btrfs_zlib_compress; 126 extern const struct btrfs_compress_op btrfs_lzo_compress; 127 extern const struct btrfs_compress_op btrfs_zstd_compress; 128 129 const char* btrfs_compress_type2str(enum btrfs_compression_type type); 130 131 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); 132 133 #endif 134