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 u8 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 struct cgroup_subsys_state *blkcg_css); 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 int btrfs_compress_str2level(unsigned int type, 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_NR_COMPRESS_TYPES = 4, 109 }; 110 111 struct workspace_manager { 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 struct list_head *btrfs_get_workspace(int type, unsigned int level); 123 void btrfs_put_workspace(int type, struct list_head *ws); 124 125 struct btrfs_compress_op { 126 struct workspace_manager *workspace_manager; 127 /* Maximum level supported by the compression algorithm */ 128 unsigned int max_level; 129 unsigned int default_level; 130 }; 131 132 /* The heuristic workspaces are managed via the 0th workspace manager */ 133 #define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES 134 135 extern const struct btrfs_compress_op btrfs_heuristic_compress; 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 const char* btrfs_compress_type2str(enum btrfs_compression_type type); 141 bool btrfs_compress_is_valid_type(const char *str, size_t len); 142 143 unsigned int btrfs_compress_set_level(int type, unsigned level); 144 145 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); 146 147 #endif 148