148 lines
4.2 KiB
C
148 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_COMPRESSION_H
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#define BTRFS_COMPRESSION_H
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#include <linux/sizes.h>
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struct btrfs_inode;
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/*
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* We want to make sure that amount of RAM required to uncompress an extent is
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* reasonable, so we limit the total size in ram of a compressed extent to
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* 128k. This is a crucial number because it also controls how easily we can
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* spread reads across cpus for decompression.
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*
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* We also want to make sure the amount of IO required to do a random read is
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* reasonably small, so we limit the size of a compressed extent to 128k.
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*/
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/* Maximum length of compressed data stored on disk */
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#define BTRFS_MAX_COMPRESSED (SZ_128K)
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/* Maximum size of data before compression */
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#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
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#define BTRFS_ZLIB_DEFAULT_LEVEL 3
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struct compressed_bio {
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/* number of bios pending for this compressed extent */
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refcount_t pending_bios;
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/* the pages with the compressed data on them */
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struct page **compressed_pages;
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/* inode that owns this data */
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struct inode *inode;
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/* starting offset in the inode for our pages */
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u64 start;
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/* number of bytes in the inode we're working on */
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unsigned long len;
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/* number of bytes on disk */
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unsigned long compressed_len;
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/* the compression algorithm for this bio */
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int compress_type;
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/* number of compressed pages in the array */
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unsigned long nr_pages;
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/* IO errors */
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int errors;
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int mirror_num;
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/* for reads, this is the bio we are copying the data into */
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struct bio *orig_bio;
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/*
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* the start of a variable length array of checksums only
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* used by reads
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*/
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u8 sums[];
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};
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static inline unsigned int btrfs_compress_type(unsigned int type_level)
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{
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return (type_level & 0xF);
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}
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static inline unsigned int btrfs_compress_level(unsigned int type_level)
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{
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return ((type_level & 0xF0) >> 4);
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}
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void __init btrfs_init_compress(void);
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void __cold btrfs_exit_compress(void);
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int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
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u64 start, struct page **pages,
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unsigned long *out_pages,
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unsigned long *total_in,
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unsigned long *total_out);
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int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
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unsigned long start_byte, size_t srclen, size_t destlen);
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int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
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unsigned long total_out, u64 disk_start,
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struct bio *bio);
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blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
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unsigned long len, u64 disk_start,
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unsigned long compressed_len,
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struct page **compressed_pages,
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unsigned long nr_pages,
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unsigned int write_flags,
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struct cgroup_subsys_state *blkcg_css);
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blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
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int mirror_num, unsigned long bio_flags);
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unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
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enum btrfs_compression_type {
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BTRFS_COMPRESS_NONE = 0,
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BTRFS_COMPRESS_ZLIB = 1,
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BTRFS_COMPRESS_LZO = 2,
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BTRFS_COMPRESS_ZSTD = 3,
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BTRFS_NR_COMPRESS_TYPES = 4,
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};
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struct workspace_manager {
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struct list_head idle_ws;
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spinlock_t ws_lock;
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/* Number of free workspaces */
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int free_ws;
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/* Total number of allocated workspaces */
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atomic_t total_ws;
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/* Waiters for a free workspace */
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wait_queue_head_t ws_wait;
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};
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struct list_head *btrfs_get_workspace(int type, unsigned int level);
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void btrfs_put_workspace(int type, struct list_head *ws);
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struct btrfs_compress_op {
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struct workspace_manager *workspace_manager;
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/* Maximum level supported by the compression algorithm */
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unsigned int max_level;
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unsigned int default_level;
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};
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/* The heuristic workspaces are managed via the 0th workspace manager */
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#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
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extern const struct btrfs_compress_op btrfs_heuristic_compress;
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extern const struct btrfs_compress_op btrfs_zlib_compress;
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extern const struct btrfs_compress_op btrfs_lzo_compress;
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extern const struct btrfs_compress_op btrfs_zstd_compress;
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const char* btrfs_compress_type2str(enum btrfs_compression_type type);
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bool btrfs_compress_is_valid_type(const char *str, size_t len);
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int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
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#endif
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