xref: /illumos-gate/usr/src/uts/common/fs/zfs/zio_compress.c (revision 8e268185036f404515ce8bc575423ac390136e3f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 /*
27  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
28  */
29 
30 /*
31  * Copyright (c) 2013 by Delphix. All rights reserved.
32  */
33 
34 #include <sys/zfs_context.h>
35 #include <sys/compress.h>
36 #include <sys/spa.h>
37 #include <sys/zio.h>
38 #include <sys/zio_compress.h>
39 
40 /*
41  * Compression vectors.
42  */
43 
44 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
45 	{NULL,			NULL,			0,	"inherit"},
46 	{NULL,			NULL,			0,	"on"},
47 	{NULL,			NULL,			0,	"uncompressed"},
48 	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
49 	{NULL,			NULL,			0,	"empty"},
50 	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
51 	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
52 	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
53 	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
54 	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
55 	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
56 	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
57 	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
58 	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
59 	{zle_compress,		zle_decompress,		64,	"zle"},
60 	{lz4_compress,		lz4_decompress,		0,	"lz4"},
61 };
62 
63 enum zio_compress
64 zio_compress_select(enum zio_compress child, enum zio_compress parent)
65 {
66 	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
67 	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
68 	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
69 
70 	if (child == ZIO_COMPRESS_INHERIT)
71 		return (parent);
72 
73 	if (child == ZIO_COMPRESS_ON)
74 		return (ZIO_COMPRESS_ON_VALUE);
75 
76 	return (child);
77 }
78 
79 size_t
80 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
81 {
82 	uint64_t *word, *word_end;
83 	size_t c_len, d_len, r_len;
84 	zio_compress_info_t *ci = &zio_compress_table[c];
85 
86 	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
87 	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
88 
89 	/*
90 	 * If the data is all zeroes, we don't even need to allocate
91 	 * a block for it.  We indicate this by returning zero size.
92 	 */
93 	word_end = (uint64_t *)((char *)src + s_len);
94 	for (word = src; word < word_end; word++)
95 		if (*word != 0)
96 			break;
97 
98 	if (word == word_end)
99 		return (0);
100 
101 	if (c == ZIO_COMPRESS_EMPTY)
102 		return (s_len);
103 
104 	/* Compress at least 12.5% */
105 	d_len = P2ALIGN(s_len - (s_len >> 3), (size_t)SPA_MINBLOCKSIZE);
106 	if (d_len == 0)
107 		return (s_len);
108 
109 	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
110 
111 	if (c_len > d_len)
112 		return (s_len);
113 
114 	/*
115 	 * Cool.  We compressed at least as much as we were hoping to.
116 	 * For both security and repeatability, pad out the last sector.
117 	 */
118 	r_len = P2ROUNDUP(c_len, (size_t)SPA_MINBLOCKSIZE);
119 	if (r_len > c_len) {
120 		bzero((char *)dst + c_len, r_len - c_len);
121 		c_len = r_len;
122 	}
123 
124 	ASSERT3U(c_len, <=, d_len);
125 	ASSERT(P2PHASE(c_len, (size_t)SPA_MINBLOCKSIZE) == 0);
126 
127 	return (c_len);
128 }
129 
130 int
131 zio_decompress_data(enum zio_compress c, void *src, void *dst,
132     size_t s_len, size_t d_len)
133 {
134 	zio_compress_info_t *ci = &zio_compress_table[c];
135 
136 	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
137 		return (SET_ERROR(EINVAL));
138 
139 	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
140 }
141