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 struct btrfs_inode; 12 13 /* 14 * We want to make sure that amount of RAM required to uncompress an extent is 15 * reasonable, so we limit the total size in ram of a compressed extent to 16 * 128k. This is a crucial number because it also controls how easily we can 17 * spread reads across cpus for decompression. 18 * 19 * We also want to make sure the amount of IO required to do a random read is 20 * reasonably small, so we limit the size of a compressed extent to 128k. 21 */ 22 23 /* Maximum length of compressed data stored on disk */ 24 #define BTRFS_MAX_COMPRESSED (SZ_128K) 25 static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0); 26 27 /* Maximum size of data before compression */ 28 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K) 29 30 #define BTRFS_ZLIB_DEFAULT_LEVEL 3 31 32 struct compressed_bio { 33 /* Number of sectors with unfinished IO (unsubmitted or unfinished) */ 34 refcount_t pending_sectors; 35 36 /* Number of compressed pages in the array */ 37 unsigned int nr_pages; 38 39 /* the pages with the compressed data on them */ 40 struct page **compressed_pages; 41 42 /* inode that owns this data */ 43 struct inode *inode; 44 45 /* starting offset in the inode for our pages */ 46 u64 start; 47 48 /* Number of bytes in the inode we're working on */ 49 unsigned int len; 50 51 /* Number of bytes on disk */ 52 unsigned int compressed_len; 53 54 /* The compression algorithm for this bio */ 55 u8 compress_type; 56 57 /* Whether this is a write for writeback. */ 58 bool writeback; 59 60 /* IO errors */ 61 blk_status_t status; 62 int mirror_num; 63 64 /* for reads, this is the bio we are copying the data into */ 65 struct bio *orig_bio; 66 67 /* 68 * the start of a variable length array of checksums only 69 * used by reads 70 */ 71 u8 sums[]; 72 }; 73 74 static inline unsigned int btrfs_compress_type(unsigned int type_level) 75 { 76 return (type_level & 0xF); 77 } 78 79 static inline unsigned int btrfs_compress_level(unsigned int type_level) 80 { 81 return ((type_level & 0xF0) >> 4); 82 } 83 84 void __init btrfs_init_compress(void); 85 void __cold btrfs_exit_compress(void); 86 87 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 88 u64 start, struct page **pages, 89 unsigned long *out_pages, 90 unsigned long *total_in, 91 unsigned long *total_out); 92 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, 93 unsigned long start_byte, size_t srclen, size_t destlen); 94 int btrfs_decompress_buf2page(const char *buf, u32 buf_len, 95 struct compressed_bio *cb, u32 decompressed); 96 97 blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start, 98 unsigned int len, u64 disk_start, 99 unsigned int compressed_len, 100 struct page **compressed_pages, 101 unsigned int nr_pages, 102 unsigned int write_flags, 103 struct cgroup_subsys_state *blkcg_css, 104 bool writeback); 105 void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 106 int mirror_num); 107 108 unsigned int btrfs_compress_str2level(unsigned int type, const char *str); 109 110 enum btrfs_compression_type { 111 BTRFS_COMPRESS_NONE = 0, 112 BTRFS_COMPRESS_ZLIB = 1, 113 BTRFS_COMPRESS_LZO = 2, 114 BTRFS_COMPRESS_ZSTD = 3, 115 BTRFS_NR_COMPRESS_TYPES = 4, 116 }; 117 118 struct workspace_manager { 119 struct list_head idle_ws; 120 spinlock_t ws_lock; 121 /* Number of free workspaces */ 122 int free_ws; 123 /* Total number of allocated workspaces */ 124 atomic_t total_ws; 125 /* Waiters for a free workspace */ 126 wait_queue_head_t ws_wait; 127 }; 128 129 struct list_head *btrfs_get_workspace(int type, unsigned int level); 130 void btrfs_put_workspace(int type, struct list_head *ws); 131 132 struct btrfs_compress_op { 133 struct workspace_manager *workspace_manager; 134 /* Maximum level supported by the compression algorithm */ 135 unsigned int max_level; 136 unsigned int default_level; 137 }; 138 139 /* The heuristic workspaces are managed via the 0th workspace manager */ 140 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES 141 142 extern const struct btrfs_compress_op btrfs_heuristic_compress; 143 extern const struct btrfs_compress_op btrfs_zlib_compress; 144 extern const struct btrfs_compress_op btrfs_lzo_compress; 145 extern const struct btrfs_compress_op btrfs_zstd_compress; 146 147 const char* btrfs_compress_type2str(enum btrfs_compression_type type); 148 bool btrfs_compress_is_valid_type(const char *str, size_t len); 149 150 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); 151 152 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 153 u64 start, struct page **pages, unsigned long *out_pages, 154 unsigned long *total_in, unsigned long *total_out); 155 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb); 156 int zlib_decompress(struct list_head *ws, unsigned char *data_in, 157 struct page *dest_page, unsigned long start_byte, size_t srclen, 158 size_t destlen); 159 struct list_head *zlib_alloc_workspace(unsigned int level); 160 void zlib_free_workspace(struct list_head *ws); 161 struct list_head *zlib_get_workspace(unsigned int level); 162 163 int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, 164 u64 start, struct page **pages, unsigned long *out_pages, 165 unsigned long *total_in, unsigned long *total_out); 166 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb); 167 int lzo_decompress(struct list_head *ws, unsigned char *data_in, 168 struct page *dest_page, unsigned long start_byte, size_t srclen, 169 size_t destlen); 170 struct list_head *lzo_alloc_workspace(unsigned int level); 171 void lzo_free_workspace(struct list_head *ws); 172 173 int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, 174 u64 start, struct page **pages, unsigned long *out_pages, 175 unsigned long *total_in, unsigned long *total_out); 176 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb); 177 int zstd_decompress(struct list_head *ws, unsigned char *data_in, 178 struct page *dest_page, unsigned long start_byte, size_t srclen, 179 size_t destlen); 180 void zstd_init_workspace_manager(void); 181 void zstd_cleanup_workspace_manager(void); 182 struct list_head *zstd_alloc_workspace(unsigned int level); 183 void zstd_free_workspace(struct list_head *ws); 184 struct list_head *zstd_get_workspace(unsigned int level); 185 void zstd_put_workspace(struct list_head *ws); 186 187 #endif 188