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 #include <linux/mm.h> 11 #include <linux/list.h> 12 #include <linux/workqueue.h> 13 #include <linux/wait.h> 14 #include "bio.h" 15 16 struct address_space; 17 struct page; 18 struct inode; 19 struct btrfs_inode; 20 struct btrfs_ordered_extent; 21 struct btrfs_bio; 22 23 /* 24 * We want to make sure that amount of RAM required to uncompress an extent is 25 * reasonable, so we limit the total size in ram of a compressed extent to 26 * 128k. This is a crucial number because it also controls how easily we can 27 * spread reads across cpus for decompression. 28 * 29 * We also want to make sure the amount of IO required to do a random read is 30 * reasonably small, so we limit the size of a compressed extent to 128k. 31 */ 32 33 /* Maximum length of compressed data stored on disk */ 34 #define BTRFS_MAX_COMPRESSED (SZ_128K) 35 #define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE) 36 static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0); 37 38 /* Maximum size of data before compression */ 39 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K) 40 41 #define BTRFS_ZLIB_DEFAULT_LEVEL 3 42 43 struct compressed_bio { 44 /* Number of compressed pages in the array */ 45 unsigned int nr_pages; 46 47 /* the pages with the compressed data on them */ 48 struct page **compressed_pages; 49 50 /* starting offset in the inode for our pages */ 51 u64 start; 52 53 /* Number of bytes in the inode we're working on */ 54 unsigned int len; 55 56 /* Number of bytes on disk */ 57 unsigned int compressed_len; 58 59 /* The compression algorithm for this bio */ 60 u8 compress_type; 61 62 /* Whether this is a write for writeback. */ 63 bool writeback; 64 65 union { 66 /* For reads, this is the bio we are copying the data into */ 67 struct btrfs_bio *orig_bbio; 68 struct work_struct write_end_work; 69 }; 70 71 /* Must be last. */ 72 struct btrfs_bio bbio; 73 }; 74 75 static inline unsigned int btrfs_compress_type(unsigned int type_level) 76 { 77 return (type_level & 0xF); 78 } 79 80 static inline unsigned int btrfs_compress_level(unsigned int type_level) 81 { 82 return ((type_level & 0xF0) >> 4); 83 } 84 85 int __init btrfs_init_compress(void); 86 void __cold btrfs_exit_compress(void); 87 88 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 89 u64 start, struct page **pages, 90 unsigned long *out_pages, 91 unsigned long *total_in, 92 unsigned long *total_out); 93 int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page, 94 unsigned long start_byte, size_t srclen, size_t destlen); 95 int btrfs_decompress_buf2page(const char *buf, u32 buf_len, 96 struct compressed_bio *cb, u32 decompressed); 97 98 void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered, 99 struct page **compressed_pages, 100 unsigned int nr_pages, 101 blk_opf_t write_flags, 102 bool writeback); 103 void btrfs_submit_compressed_read(struct btrfs_bio *bbio); 104 105 unsigned int btrfs_compress_str2level(unsigned int type, const char *str); 106 107 struct page *btrfs_alloc_compr_page(void); 108 void btrfs_free_compr_page(struct page *page); 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, const u8 *data_in, 157 struct page *dest_page, unsigned long dest_pgoff, 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, const u8 *data_in, 168 struct page *dest_page, unsigned long dest_pgoff, 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, const u8 *data_in, 178 struct page *dest_page, unsigned long dest_pgoff, 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