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Diffstat (limited to 'fs/btrfs/compression.h')
| -rw-r--r-- | fs/btrfs/compression.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h new file mode 100644 index 000000000..03bb9d143 --- /dev/null +++ b/fs/btrfs/compression.h @@ -0,0 +1,176 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2008 Oracle. All rights reserved. + */ + +#ifndef BTRFS_COMPRESSION_H +#define BTRFS_COMPRESSION_H + +#include <linux/sizes.h> +#include "bio.h" + +struct btrfs_inode; +struct btrfs_ordered_extent; + +/* + * We want to make sure that amount of RAM required to uncompress an extent is + * reasonable, so we limit the total size in ram of a compressed extent to + * 128k. This is a crucial number because it also controls how easily we can + * spread reads across cpus for decompression. + * + * We also want to make sure the amount of IO required to do a random read is + * reasonably small, so we limit the size of a compressed extent to 128k. + */ + +/* Maximum length of compressed data stored on disk */ +#define BTRFS_MAX_COMPRESSED (SZ_128K) +#define BTRFS_MAX_COMPRESSED_PAGES (BTRFS_MAX_COMPRESSED / PAGE_SIZE) +static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0); + +/* Maximum size of data before compression */ +#define BTRFS_MAX_UNCOMPRESSED (SZ_128K) + +#define BTRFS_ZLIB_DEFAULT_LEVEL 3 + +struct compressed_bio { + /* Number of compressed pages in the array */ + unsigned int nr_pages; + + /* the pages with the compressed data on them */ + struct page **compressed_pages; + + /* starting offset in the inode for our pages */ + u64 start; + + /* Number of bytes in the inode we're working on */ + unsigned int len; + + /* Number of bytes on disk */ + unsigned int compressed_len; + + /* The compression algorithm for this bio */ + u8 compress_type; + + /* Whether this is a write for writeback. */ + bool writeback; + + union { + /* For reads, this is the bio we are copying the data into */ + struct btrfs_bio *orig_bbio; + struct work_struct write_end_work; + }; + + /* Must be last. */ + struct btrfs_bio bbio; +}; + +static inline unsigned int btrfs_compress_type(unsigned int type_level) +{ + return (type_level & 0xF); +} + +static inline unsigned int btrfs_compress_level(unsigned int type_level) +{ + return ((type_level & 0xF0) >> 4); +} + +int __init btrfs_init_compress(void); +void __cold btrfs_exit_compress(void); + +int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, + u64 start, struct page **pages, + unsigned long *out_pages, + unsigned long *total_in, + unsigned long *total_out); +int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page, + unsigned long start_byte, size_t srclen, size_t destlen); +int btrfs_decompress_buf2page(const char *buf, u32 buf_len, + struct compressed_bio *cb, u32 decompressed); + +void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered, + struct page **compressed_pages, + unsigned int nr_pages, + blk_opf_t write_flags, + bool writeback); +void btrfs_submit_compressed_read(struct btrfs_bio *bbio); + +unsigned int btrfs_compress_str2level(unsigned int type, const char *str); + +enum btrfs_compression_type { + BTRFS_COMPRESS_NONE = 0, + BTRFS_COMPRESS_ZLIB = 1, + BTRFS_COMPRESS_LZO = 2, + BTRFS_COMPRESS_ZSTD = 3, + BTRFS_NR_COMPRESS_TYPES = 4, +}; + +struct workspace_manager { + struct list_head idle_ws; + spinlock_t ws_lock; + /* Number of free workspaces */ + int free_ws; + /* Total number of allocated workspaces */ + atomic_t total_ws; + /* Waiters for a free workspace */ + wait_queue_head_t ws_wait; +}; + +struct list_head *btrfs_get_workspace(int type, unsigned int level); +void btrfs_put_workspace(int type, struct list_head *ws); + +struct btrfs_compress_op { + struct workspace_manager *workspace_manager; + /* Maximum level supported by the compression algorithm */ + unsigned int max_level; + unsigned int default_level; +}; + +/* The heuristic workspaces are managed via the 0th workspace manager */ +#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES + +extern const struct btrfs_compress_op btrfs_heuristic_compress; +extern const struct btrfs_compress_op btrfs_zlib_compress; +extern const struct btrfs_compress_op btrfs_lzo_compress; +extern const struct btrfs_compress_op btrfs_zstd_compress; + +const char* btrfs_compress_type2str(enum btrfs_compression_type type); +bool btrfs_compress_is_valid_type(const char *str, size_t len); + +int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); + +int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, + u64 start, struct page **pages, unsigned long *out_pages, + unsigned long *total_in, unsigned long *total_out); +int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb); +int zlib_decompress(struct list_head *ws, const u8 *data_in, + struct page *dest_page, unsigned long start_byte, size_t srclen, + size_t destlen); +struct list_head *zlib_alloc_workspace(unsigned int level); +void zlib_free_workspace(struct list_head *ws); +struct list_head *zlib_get_workspace(unsigned int level); + +int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, + u64 start, struct page **pages, unsigned long *out_pages, + unsigned long *total_in, unsigned long *total_out); +int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb); +int lzo_decompress(struct list_head *ws, const u8 *data_in, + struct page *dest_page, unsigned long start_byte, size_t srclen, + size_t destlen); +struct list_head *lzo_alloc_workspace(unsigned int level); +void lzo_free_workspace(struct list_head *ws); + +int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, + u64 start, struct page **pages, unsigned long *out_pages, + unsigned long *total_in, unsigned long *total_out); +int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb); +int zstd_decompress(struct list_head *ws, const u8 *data_in, + struct page *dest_page, unsigned long start_byte, size_t srclen, + size_t destlen); +void zstd_init_workspace_manager(void); +void zstd_cleanup_workspace_manager(void); +struct list_head *zstd_alloc_workspace(unsigned int level); +void zstd_free_workspace(struct list_head *ws); +struct list_head *zstd_get_workspace(unsigned int level); +void zstd_put_workspace(struct list_head *ws); + +#endif |