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/kstat.h>
37#include <sys/spa.h>
38#include <sys/zio.h>
39#include <sys/zio_compress.h>
40
41typedef struct zcomp_stats {
42	kstat_named_t zcompstat_attempts;
43	kstat_named_t zcompstat_empty;
44	kstat_named_t zcompstat_skipped_minblocksize;
45	kstat_named_t zcompstat_skipped_insufficient_gain;
46} zcomp_stats_t;
47
48static zcomp_stats_t zcomp_stats = {
49	{ "attempts",			KSTAT_DATA_UINT64 },
50	{ "empty",			KSTAT_DATA_UINT64 },
51	{ "skipped_minblocksize",	KSTAT_DATA_UINT64 },
52	{ "skipped_insufficient_gain",	KSTAT_DATA_UINT64 }
53};
54
55#define	ZCOMPSTAT_INCR(stat, val) \
56	atomic_add_64(&zcomp_stats.stat.value.ui64, (val));
57
58#define	ZCOMPSTAT_BUMP(stat)		ZCOMPSTAT_INCR(stat, 1);
59
60kstat_t		*zcomp_ksp;
61
62/*
63 * Compression vectors.
64 */
65
66zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
67	{NULL,			NULL,			0,	"inherit"},
68	{NULL,			NULL,			0,	"on"},
69	{NULL,			NULL,			0,	"uncompressed"},
70	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
71	{NULL,			NULL,			0,	"empty"},
72	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
73	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
74	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
75	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
76	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
77	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
78	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
79	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
80	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
81	{zle_compress,		zle_decompress,		64,	"zle"},
82	{lz4_compress,		lz4_decompress,		0,	"lz4"},
83};
84
85enum zio_compress
86zio_compress_select(enum zio_compress child, enum zio_compress parent)
87{
88	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
89	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
90	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
91
92	if (child == ZIO_COMPRESS_INHERIT)
93		return (parent);
94
95	if (child == ZIO_COMPRESS_ON)
96		return (ZIO_COMPRESS_ON_VALUE);
97
98	return (child);
99}
100
101size_t
102zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len,
103    size_t minblocksize)
104{
105	uint64_t *word, *word_end;
106	size_t c_len, d_len, r_len;
107	zio_compress_info_t *ci = &zio_compress_table[c];
108
109	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
110	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
111
112	ZCOMPSTAT_BUMP(zcompstat_attempts);
113
114	/*
115	 * If the data is all zeroes, we don't even need to allocate
116	 * a block for it.  We indicate this by returning zero size.
117	 */
118	word_end = (uint64_t *)((char *)src + s_len);
119	for (word = src; word < word_end; word++)
120		if (*word != 0)
121			break;
122
123	if (word == word_end) {
124		ZCOMPSTAT_BUMP(zcompstat_empty);
125 		return (0);
126	}
127
128	if (c == ZIO_COMPRESS_EMPTY)
129		return (s_len);
130
131	/* Compress at least 12.5% */
132	d_len = P2ALIGN(s_len - (s_len >> 3), minblocksize);
133	if (d_len == 0) {
134		ZCOMPSTAT_BUMP(zcompstat_skipped_minblocksize);
135		return (s_len);
136	}
137
138	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
139
140	if (c_len > d_len) {
141		ZCOMPSTAT_BUMP(zcompstat_skipped_insufficient_gain);
142		return (s_len);
143	}
144
145	/*
146	 * Cool.  We compressed at least as much as we were hoping to.
147	 * For both security and repeatability, pad out the last sector.
148	 */
149	r_len = P2ROUNDUP(c_len, minblocksize);
150	if (r_len > c_len) {
151		bzero((char *)dst + c_len, r_len - c_len);
152		c_len = r_len;
153	}
154
155	ASSERT3U(c_len, <=, d_len);
156	ASSERT(P2PHASE(c_len, minblocksize) == 0);
157
158	return (c_len);
159}
160
161int
162zio_decompress_data(enum zio_compress c, void *src, void *dst,
163    size_t s_len, size_t d_len)
164{
165	zio_compress_info_t *ci = &zio_compress_table[c];
166
167	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
168		return (SET_ERROR(EINVAL));
169
170	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
171}
172
173void
174zio_compress_init(void)
175{
176
177	zcomp_ksp = kstat_create("zfs", 0, "zcompstats", "misc",
178	    KSTAT_TYPE_NAMED, sizeof (zcomp_stats) / sizeof (kstat_named_t),
179	    KSTAT_FLAG_VIRTUAL);
180
181	if (zcomp_ksp != NULL) {
182		zcomp_ksp->ks_data = &zcomp_stats;
183		kstat_install(zcomp_ksp);
184	}
185}
186
187void
188zio_compress_fini(void)
189{
190	if (zcomp_ksp != NULL) {
191		kstat_delete(zcomp_ksp);
192		zcomp_ksp = NULL;
193	}
194}
195