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      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 #include <sys/zfs_context.h>
     28 #include <sys/compress.h>
     29 #include <sys/spa.h>
     30 #include <sys/zio.h>
     31 #include <sys/zio_compress.h>
     32 
     33 /*
     34  * Compression vectors.
     35  */
     36 
     37 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
     38 	{NULL,			NULL,			0,	"inherit"},
     39 	{NULL,			NULL,			0,	"on"},
     40 	{NULL,			NULL,			0,	"uncompressed"},
     41 	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
     42 	{NULL,			NULL,			0,	"empty"},
     43 	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
     44 	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
     45 	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
     46 	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
     47 	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
     48 	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
     49 	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
     50 	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
     51 	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
     52 	{zle_compress,		zle_decompress,		64,	"zle"},
     53 };
     54 
     55 enum zio_compress
     56 zio_compress_select(enum zio_compress child, enum zio_compress parent)
     57 {
     58 	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
     59 	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
     60 	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
     61 
     62 	if (child == ZIO_COMPRESS_INHERIT)
     63 		return (parent);
     64 
     65 	if (child == ZIO_COMPRESS_ON)
     66 		return (ZIO_COMPRESS_ON_VALUE);
     67 
     68 	return (child);
     69 }
     70 
     71 size_t
     72 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
     73 {
     74 	uint64_t *word, *word_end;
     75 	size_t c_len, d_len, r_len;
     76 	zio_compress_info_t *ci = &zio_compress_table[c];
     77 
     78 	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
     79 	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
     80 
     81 	/*
     82 	 * If the data is all zeroes, we don't even need to allocate
     83 	 * a block for it.  We indicate this by returning zero size.
     84 	 */
     85 	word_end = (uint64_t *)((char *)src + s_len);
     86 	for (word = src; word < word_end; word++)
     87 		if (*word != 0)
     88 			break;
     89 
     90 	if (word == word_end)
     91 		return (0);
     92 
     93 	if (c == ZIO_COMPRESS_EMPTY)
     94 		return (s_len);
     95 
     96 	/* Compress at least 12.5% */
     97 	d_len = P2ALIGN(s_len - (s_len >> 3), (size_t)SPA_MINBLOCKSIZE);
     98 	if (d_len == 0)
     99 		return (s_len);
    100 
    101 	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
    102 
    103 	if (c_len > d_len)
    104 		return (s_len);
    105 
    106 	/*
    107 	 * Cool.  We compressed at least as much as we were hoping to.
    108 	 * For both security and repeatability, pad out the last sector.
    109 	 */
    110 	r_len = P2ROUNDUP(c_len, (size_t)SPA_MINBLOCKSIZE);
    111 	if (r_len > c_len) {
    112 		bzero((char *)dst + c_len, r_len - c_len);
    113 		c_len = r_len;
    114 	}
    115 
    116 	ASSERT3U(c_len, <=, d_len);
    117 	ASSERT(P2PHASE(c_len, (size_t)SPA_MINBLOCKSIZE) == 0);
    118 
    119 	return (c_len);
    120 }
    121 
    122 int
    123 zio_decompress_data(enum zio_compress c, void *src, void *dst,
    124     size_t s_len, size_t d_len)
    125 {
    126 	zio_compress_info_t *ci = &zio_compress_table[c];
    127 
    128 	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
    129 		return (EINVAL);
    130 
    131 	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
    132 }
    133