summaryrefslogtreecommitdiffstats
path: root/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_compress.c
blob: c563be4eb9557086bbde5238a25cd50def097f22 (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
137
138
139
140
141
142
143
144
145
146
147
148
/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#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"},
};

uint8_t
zio_compress_select(uint8_t child, uint8_t 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);
}

int
zio_compress_data(int cpfunc, void *src, uint64_t srcsize, void **destp,
    uint64_t *destsizep, uint64_t *destbufsizep)
{
	uint64_t *word, *word_end;
	uint64_t ciosize, gapsize, destbufsize;
	zio_compress_info_t *ci = &zio_compress_table[cpfunc];
	char *dest;
	uint_t allzero;

	ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);
	ASSERT((uint_t)cpfunc == 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 setting *destsizep = 0.
	 */
	allzero = 1;
	word = src;
	word_end = (uint64_t *)(uintptr_t)((uintptr_t)word + srcsize);
	while (word < word_end) {
		if (*word++ != 0) {
			allzero = 0;
			break;
		}
	}
	if (allzero) {
		*destp = NULL;
		*destsizep = 0;
		*destbufsizep = 0;
		return (1);
	}

	if (cpfunc == ZIO_COMPRESS_EMPTY)
		return (0);

	/* Compress at least 12.5% */
	destbufsize = P2ALIGN(srcsize - (srcsize >> 3), SPA_MINBLOCKSIZE);
	if (destbufsize == 0)
		return (0);
	dest = zio_buf_alloc(destbufsize);

	ciosize = ci->ci_compress(src, dest, (size_t)srcsize,
	    (size_t)destbufsize, ci->ci_level);
	if (ciosize > destbufsize) {
		zio_buf_free(dest, destbufsize);
		return (0);
	}

	/* Cool.  We compressed at least as much as we were hoping to. */

	/* For security, make sure we don't write random heap crap to disk */
	gapsize = P2ROUNDUP(ciosize, SPA_MINBLOCKSIZE) - ciosize;
	if (gapsize != 0) {
		bzero(dest + ciosize, gapsize);
		ciosize += gapsize;
	}

	ASSERT3U(ciosize, <=, destbufsize);
	ASSERT(P2PHASE(ciosize, SPA_MINBLOCKSIZE) == 0);
	*destp = dest;
	*destsizep = ciosize;
	*destbufsizep = destbufsize;

	return (1);
}

int
zio_decompress_data(int cpfunc, void *src, uint64_t srcsize,
	void *dest, uint64_t destsize)
{
	zio_compress_info_t *ci = &zio_compress_table[cpfunc];

	ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);

	return (ci->ci_decompress(src, dest, srcsize, destsize, ci->ci_level));
}
OpenPOWER on IntegriCloud