aboutsummaryrefslogtreecommitdiffstats
path: root/module/zfs/zio_compress.c
blob: 5864d5c8a1a99df57908c42c18ddfa28add3c470 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
 */

#include <sys/zfs_context.h>
#include <sys/compress.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/zio_compress.h>

/*
 * Compression vectors.
 */

zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
	{NULL,			NULL,			0,	"inherit"},
	{NULL,			NULL,			0,	"on"},
	{NULL,			NULL,			0,	"uncompressed"},
	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
	{NULL,			NULL,			0,	"empty"},
	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
	{zle_compress,		zle_decompress,		64,	"zle"},
	{lz4_compress_zfs,	lz4_decompress_zfs,	0,	"lz4"},
};

enum zio_compress
zio_compress_select(enum zio_compress child, enum zio_compress parent)
{
	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);

	if (child == ZIO_COMPRESS_INHERIT)
		return (parent);

	if (child == ZIO_COMPRESS_ON)
		return (ZIO_COMPRESS_ON_VALUE);

	return (child);
}

size_t
zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
{
	uint64_t *word, *word_end;
	size_t c_len, d_len, r_len;
	zio_compress_info_t *ci = &zio_compress_table[c];

	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);

	/*
	 * If the data is all zeroes, we don't even need to allocate
	 * a block for it.  We indicate this by returning zero size.
	 */
	word_end = (uint64_t *)((char *)src + s_len);
	for (word = src; word < word_end; word++)
		if (*word != 0)
			break;

	if (word == word_end)
		return (0);

	if (c == ZIO_COMPRESS_EMPTY)
		return (s_len);

	/* Compress at least 12.5% */
	d_len = P2ALIGN(s_len - (s_len >> 3), (size_t)SPA_MINBLOCKSIZE);
	if (d_len == 0)
		return (s_len);

	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);

	if (c_len > d_len)
		return (s_len);

	/*
	 * Cool.  We compressed at least as much as we were hoping to.
	 * For both security and repeatability, pad out the last sector.
	 */
	r_len = P2ROUNDUP(c_len, (size_t)SPA_MINBLOCKSIZE);
	if (r_len > c_len) {
		bzero((char *)dst + c_len, r_len - c_len);
		c_len = r_len;
	}

	ASSERT3U(c_len, <=, d_len);
	ASSERT(P2PHASE(c_len, (size_t)SPA_MINBLOCKSIZE) == 0);

	return (c_len);
}

int
zio_decompress_data(enum zio_compress c, void *src, void *dst,
    size_t s_len, size_t d_len)
{
	zio_compress_info_t *ci = &zio_compress_table[c];

	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
		return (EINVAL);

	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
}