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 static inline unsigned int btrfs_compress_type(unsigned int type_level) 68 { 69 return (type_level & 0xF); 70 } 71 72 static inline unsigned int btrfs_compress_level(unsigned int type_level) 73 { 74 return ((type_level & 0xF0) >> 4); 75 } 76 77 void __init btrfs_init_compress(void); 78 void __cold btrfs_exit_compress(void); 79 80 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 81 u64 start, struct page **pages, 82 unsigned long *out_pages, 83 unsigned long *total_in, 84 unsigned long *total_out); 85 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, 86 unsigned long start_byte, size_t srclen, size_t destlen); 87 int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, 88 unsigned long total_out, u64 disk_start, 89 struct bio *bio); 90 91 blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, 92 unsigned long len, u64 disk_start, 93 unsigned long compressed_len, 94 struct page **compressed_pages, 95 unsigned long nr_pages, 96 unsigned int write_flags); 97 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 98 int mirror_num, unsigned long bio_flags); 99 100 unsigned int btrfs_compress_str2level(unsigned int type, const char *str); 101 102 enum btrfs_compression_type { 103 BTRFS_COMPRESS_NONE = 0, 104 BTRFS_COMPRESS_ZLIB = 1, 105 BTRFS_COMPRESS_LZO = 2, 106 BTRFS_COMPRESS_ZSTD = 3, 107 BTRFS_COMPRESS_TYPES = 3, 108 }; 109 110 struct workspace_manager { 111 const struct btrfs_compress_op *ops; 112 struct list_head idle_ws; 113 spinlock_t ws_lock; 114 /* Number of free workspaces */ 115 int free_ws; 116 /* Total number of allocated workspaces */ 117 atomic_t total_ws; 118 /* Waiters for a free workspace */ 119 wait_queue_head_t ws_wait; 120 }; 121 122 void btrfs_init_workspace_manager(struct workspace_manager *wsm, 123 const struct btrfs_compress_op *ops); 124 struct list_head *btrfs_get_workspace(struct workspace_manager *wsm, 125 unsigned int level); 126 void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws); 127 void btrfs_cleanup_workspace_manager(struct workspace_manager *wsm); 128 129 struct btrfs_compress_op { 130 void (*init_workspace_manager)(void); 131 132 void (*cleanup_workspace_manager)(void); 133 134 struct list_head *(*get_workspace)(unsigned int level); 135 136 void (*put_workspace)(struct list_head *ws); 137 138 struct list_head *(*alloc_workspace)(unsigned int level); 139 140 void (*free_workspace)(struct list_head *workspace); 141 142 int (*compress_pages)(struct list_head *workspace, 143 struct address_space *mapping, 144 u64 start, 145 struct page **pages, 146 unsigned long *out_pages, 147 unsigned long *total_in, 148 unsigned long *total_out); 149 150 int (*decompress_bio)(struct list_head *workspace, 151 struct compressed_bio *cb); 152 153 int (*decompress)(struct list_head *workspace, 154 unsigned char *data_in, 155 struct page *dest_page, 156 unsigned long start_byte, 157 size_t srclen, size_t destlen); 158 159 /* 160 * This bounds the level set by the user to be within range of a 161 * particular compression type. It returns the level that will be used 162 * if the level is out of bounds or the default if 0 is passed in. 163 */ 164 unsigned int (*set_level)(unsigned int level); 165 }; 166 167 /* The heuristic workspaces are managed via the 0th workspace manager */ 168 #define BTRFS_NR_WORKSPACE_MANAGERS (BTRFS_COMPRESS_TYPES + 1) 169 170 extern const struct btrfs_compress_op btrfs_heuristic_compress; 171 extern const struct btrfs_compress_op btrfs_zlib_compress; 172 extern const struct btrfs_compress_op btrfs_lzo_compress; 173 extern const struct btrfs_compress_op btrfs_zstd_compress; 174 175 const char* btrfs_compress_type2str(enum btrfs_compression_type type); 176 177 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); 178 179 #endif 180