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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 2007 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     28 
     29 #include <sys/zfs_context.h>
     30 #include <sys/compress.h>
     31 #include <sys/spa.h>
     32 #include <sys/zio.h>
     33 #include <sys/zio_compress.h>
     34 
     35 /*
     36  * Compression vectors.
     37  */
     38 
     39 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
     40 	{NULL,			NULL,			0,	"inherit"},
     41 	{NULL,			NULL,			0,	"on"},
     42 	{NULL,			NULL,			0,	"uncompressed"},
     43 	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
     44 	{NULL,			NULL,			0,	"empty"},
     45 	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
     46 	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
     47 	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
     48 	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
     49 	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
     50 	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
     51 	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
     52 	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
     53 	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
     54 };
     55 
     56 uint8_t
     57 zio_compress_select(uint8_t child, uint8_t parent)
     58 {
     59 	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
     60 	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
     61 	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
     62 
     63 	if (child == ZIO_COMPRESS_INHERIT)
     64 		return (parent);
     65 
     66 	if (child == ZIO_COMPRESS_ON)
     67 		return (ZIO_COMPRESS_ON_VALUE);
     68 
     69 	return (child);
     70 }
     71 
     72 int
     73 zio_compress_data(int cpfunc, void *src, uint64_t srcsize, void **destp,
     74     uint64_t *destsizep, uint64_t *destbufsizep)
     75 {
     76 	uint64_t *word, *word_end;
     77 	uint64_t ciosize, gapsize, destbufsize;
     78 	zio_compress_info_t *ci = &zio_compress_table[cpfunc];
     79 	char *dest;
     80 	uint_t allzero;
     81 
     82 	ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);
     83 	ASSERT((uint_t)cpfunc == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
     84 
     85 	/*
     86 	 * If the data is all zeroes, we don't even need to allocate
     87 	 * a block for it.  We indicate this by setting *destsizep = 0.
     88 	 */
     89 	allzero = 1;
     90 	word = src;
     91 	word_end = (uint64_t *)(uintptr_t)((uintptr_t)word + srcsize);
     92 	while (word < word_end) {
     93 		if (*word++ != 0) {
     94 			allzero = 0;
     95 			break;
     96 		}
     97 	}
     98 	if (allzero) {
     99 		*destp = NULL;
    100 		*destsizep = 0;
    101 		*destbufsizep = 0;
    102 		return (1);
    103 	}
    104 
    105 	if (cpfunc == ZIO_COMPRESS_EMPTY)
    106 		return (0);
    107 
    108 	/* Compress at least 12.5% */
    109 	destbufsize = P2ALIGN(srcsize - (srcsize >> 3), SPA_MINBLOCKSIZE);
    110 	if (destbufsize == 0)
    111 		return (0);
    112 	dest = zio_buf_alloc(destbufsize);
    113 
    114 	ciosize = ci->ci_compress(src, dest, (size_t)srcsize,
    115 	    (size_t)destbufsize, ci->ci_level);
    116 	if (ciosize > destbufsize) {
    117 		zio_buf_free(dest, destbufsize);
    118 		return (0);
    119 	}
    120 
    121 	/* Cool.  We compressed at least as much as we were hoping to. */
    122 
    123 	/* For security, make sure we don't write random heap crap to disk */
    124 	gapsize = P2ROUNDUP(ciosize, SPA_MINBLOCKSIZE) - ciosize;
    125 	if (gapsize != 0) {
    126 		bzero(dest + ciosize, gapsize);
    127 		ciosize += gapsize;
    128 	}
    129 
    130 	ASSERT3U(ciosize, <=, destbufsize);
    131 	ASSERT(P2PHASE(ciosize, SPA_MINBLOCKSIZE) == 0);
    132 	*destp = dest;
    133 	*destsizep = ciosize;
    134 	*destbufsizep = destbufsize;
    135 
    136 	return (1);
    137 }
    138 
    139 int
    140 zio_decompress_data(int cpfunc, void *src, uint64_t srcsize,
    141 	void *dest, uint64_t destsize)
    142 {
    143 	zio_compress_info_t *ci = &zio_compress_table[cpfunc];
    144 
    145 	ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);
    146 
    147 	return (ci->ci_decompress(src, dest, srcsize, destsize, ci->ci_level));
    148 }
    149