xref: /titanic_51/usr/src/uts/common/fs/zfs/zio_compress.c (revision b819cea2f73f98c5662230cc9affc8cc84f77fcf)
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/zfeature.h>
38 #include <sys/zio.h>
39 #include <sys/zio_compress.h>
40 
41 /*
42  * Compression vectors.
43  */
44 
45 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
46 	{NULL,			NULL,			0,	"inherit"},
47 	{NULL,			NULL,			0,	"on"},
48 	{NULL,			NULL,			0,	"uncompressed"},
49 	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
50 	{NULL,			NULL,			0,	"empty"},
51 	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
52 	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
53 	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
54 	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
55 	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
56 	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
57 	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
58 	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
59 	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
60 	{zle_compress,		zle_decompress,		64,	"zle"},
61 	{lz4_compress,		lz4_decompress,		0,	"lz4"},
62 };
63 
64 enum zio_compress
65 zio_compress_select(spa_t *spa, enum zio_compress child,
66     enum zio_compress parent)
67 {
68 	enum zio_compress result;
69 
70 	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
71 	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
72 	ASSERT(parent != ZIO_COMPRESS_INHERIT);
73 
74 	result = child;
75 	if (result == ZIO_COMPRESS_INHERIT)
76 		result = parent;
77 
78 	if (result == ZIO_COMPRESS_ON) {
79 		if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
80 			result = ZIO_COMPRESS_LZ4_ON_VALUE;
81 		else
82 			result = ZIO_COMPRESS_LEGACY_ON_VALUE;
83 	}
84 
85 	return (result);
86 }
87 
88 size_t
89 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
90 {
91 	uint64_t *word, *word_end;
92 	size_t c_len, d_len;
93 	zio_compress_info_t *ci = &zio_compress_table[c];
94 
95 	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
96 	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
97 
98 	/*
99 	 * If the data is all zeroes, we don't even need to allocate
100 	 * a block for it.  We indicate this by returning zero size.
101 	 */
102 	word_end = (uint64_t *)((char *)src + s_len);
103 	for (word = src; word < word_end; word++)
104 		if (*word != 0)
105 			break;
106 
107 	if (word == word_end)
108 		return (0);
109 
110 	if (c == ZIO_COMPRESS_EMPTY)
111 		return (s_len);
112 
113 	/* Compress at least 12.5% */
114 	d_len = s_len - (s_len >> 3);
115 	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
116 
117 	if (c_len > d_len)
118 		return (s_len);
119 
120 	ASSERT3U(c_len, <=, d_len);
121 	return (c_len);
122 }
123 
124 int
125 zio_decompress_data(enum zio_compress c, void *src, void *dst,
126     size_t s_len, size_t d_len)
127 {
128 	zio_compress_info_t *ci = &zio_compress_table[c];
129 
130 	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
131 		return (SET_ERROR(EINVAL));
132 
133 	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
134 }
135