zfs/module/zfs/zio_compress.c

149 lines
4.0 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/zfs_context.h>
#include <sys/compress.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/zio_compress.h>
/*
* Compression vectors.
*/
zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
{NULL, NULL, 0, "inherit"},
{NULL, NULL, 0, "on"},
{NULL, NULL, 0, "uncompressed"},
{lzjb_compress, lzjb_decompress, 0, "lzjb"},
{NULL, NULL, 0, "empty"},
{gzip_compress, gzip_decompress, 1, "gzip-1"},
{gzip_compress, gzip_decompress, 2, "gzip-2"},
{gzip_compress, gzip_decompress, 3, "gzip-3"},
{gzip_compress, gzip_decompress, 4, "gzip-4"},
{gzip_compress, gzip_decompress, 5, "gzip-5"},
{gzip_compress, gzip_decompress, 6, "gzip-6"},
{gzip_compress, gzip_decompress, 7, "gzip-7"},
{gzip_compress, gzip_decompress, 8, "gzip-8"},
{gzip_compress, gzip_decompress, 9, "gzip-9"},
};
uint8_t
zio_compress_select(uint8_t child, uint8_t parent)
{
ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
if (child == ZIO_COMPRESS_INHERIT)
return (parent);
if (child == ZIO_COMPRESS_ON)
return (ZIO_COMPRESS_ON_VALUE);
return (child);
}
int
zio_compress_data(int cpfunc, void *src, uint64_t srcsize, void **destp,
uint64_t *destsizep, uint64_t *destbufsizep)
{
uint64_t *word, *word_end;
uint64_t ciosize, gapsize, destbufsize;
zio_compress_info_t *ci = &zio_compress_table[cpfunc];
char *dest;
uint_t allzero;
ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);
ASSERT((uint_t)cpfunc == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
/*
* If the data is all zeroes, we don't even need to allocate
* a block for it. We indicate this by setting *destsizep = 0.
*/
allzero = 1;
word = src;
word_end = (uint64_t *)(uintptr_t)((uintptr_t)word + srcsize);
while (word < word_end) {
if (*word++ != 0) {
allzero = 0;
break;
}
}
if (allzero) {
*destp = NULL;
*destsizep = 0;
*destbufsizep = 0;
return (1);
}
if (cpfunc == ZIO_COMPRESS_EMPTY)
return (0);
/* Compress at least 12.5% */
destbufsize = P2ALIGN(srcsize - (srcsize >> 3), SPA_MINBLOCKSIZE);
if (destbufsize == 0)
return (0);
dest = zio_buf_alloc(destbufsize);
ciosize = ci->ci_compress(src, dest, (size_t)srcsize,
(size_t)destbufsize, ci->ci_level);
if (ciosize > destbufsize) {
zio_buf_free(dest, destbufsize);
return (0);
}
/* Cool. We compressed at least as much as we were hoping to. */
/* For security, make sure we don't write random heap crap to disk */
gapsize = P2ROUNDUP(ciosize, SPA_MINBLOCKSIZE) - ciosize;
if (gapsize != 0) {
bzero(dest + ciosize, gapsize);
ciosize += gapsize;
}
ASSERT3U(ciosize, <=, destbufsize);
ASSERT(P2PHASE(ciosize, SPA_MINBLOCKSIZE) == 0);
*destp = dest;
*destsizep = ciosize;
*destbufsizep = destbufsize;
return (1);
}
int
zio_decompress_data(int cpfunc, void *src, uint64_t srcsize,
void *dest, uint64_t destsize)
{
zio_compress_info_t *ci = &zio_compress_table[cpfunc];
ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS);
return (ci->ci_decompress(src, dest, srcsize, destsize, ci->ci_level));
}