mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race
[linux/fpc-iii.git] / fs / btrfs / compression.h
blob0b185e277df4bc736657468151b041a75633626c
1 /*
2 * Copyright (C) 2008 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #ifndef __BTRFS_COMPRESSION_
20 #define __BTRFS_COMPRESSION_
23 * We want to make sure that amount of RAM required to uncompress an extent is
24 * reasonable, so we limit the total size in ram of a compressed extent to
25 * 128k. This is a crucial number because it also controls how easily we can
26 * spread reads across cpus for decompression.
28 * We also want to make sure the amount of IO required to do a random read is
29 * reasonably small, so we limit the size of a compressed extent to 128k.
32 /* Maximum length of compressed data stored on disk */
33 #define BTRFS_MAX_COMPRESSED (SZ_128K)
34 /* Maximum size of data before compression */
35 #define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
37 struct compressed_bio {
38 /* number of bios pending for this compressed extent */
39 refcount_t pending_bios;
41 /* the pages with the compressed data on them */
42 struct page **compressed_pages;
44 /* inode that owns this data */
45 struct inode *inode;
47 /* starting offset in the inode for our pages */
48 u64 start;
50 /* number of bytes in the inode we're working on */
51 unsigned long len;
53 /* number of bytes on disk */
54 unsigned long compressed_len;
56 /* the compression algorithm for this bio */
57 int compress_type;
59 /* number of compressed pages in the array */
60 unsigned long nr_pages;
62 /* IO errors */
63 int errors;
64 int mirror_num;
66 /* for reads, this is the bio we are copying the data into */
67 struct bio *orig_bio;
70 * the start of a variable length array of checksums only
71 * used by reads
73 u32 sums;
76 void btrfs_init_compress(void);
77 void btrfs_exit_compress(void);
79 int btrfs_compress_pages(int type, struct address_space *mapping,
80 u64 start, struct page **pages,
81 unsigned long *out_pages,
82 unsigned long *total_in,
83 unsigned long *total_out);
84 int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
85 unsigned long start_byte, size_t srclen, size_t destlen);
86 int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
87 unsigned long total_out, u64 disk_start,
88 struct bio *bio);
90 blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
91 unsigned long len, u64 disk_start,
92 unsigned long compressed_len,
93 struct page **compressed_pages,
94 unsigned long nr_pages);
95 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
96 int mirror_num, unsigned long bio_flags);
98 enum btrfs_compression_type {
99 BTRFS_COMPRESS_NONE = 0,
100 BTRFS_COMPRESS_ZLIB = 1,
101 BTRFS_COMPRESS_LZO = 2,
102 BTRFS_COMPRESS_ZSTD = 3,
103 BTRFS_COMPRESS_TYPES = 3,
106 struct btrfs_compress_op {
107 struct list_head *(*alloc_workspace)(void);
109 void (*free_workspace)(struct list_head *workspace);
111 int (*compress_pages)(struct list_head *workspace,
112 struct address_space *mapping,
113 u64 start,
114 struct page **pages,
115 unsigned long *out_pages,
116 unsigned long *total_in,
117 unsigned long *total_out);
119 int (*decompress_bio)(struct list_head *workspace,
120 struct compressed_bio *cb);
122 int (*decompress)(struct list_head *workspace,
123 unsigned char *data_in,
124 struct page *dest_page,
125 unsigned long start_byte,
126 size_t srclen, size_t destlen);
129 extern const struct btrfs_compress_op btrfs_zlib_compress;
130 extern const struct btrfs_compress_op btrfs_lzo_compress;
131 extern const struct btrfs_compress_op btrfs_zstd_compress;
133 const char* btrfs_compress_type2str(enum btrfs_compression_type type);
134 bool btrfs_compress_is_valid_type(const char *str, size_t len);
136 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
138 #endif