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Diffstat (limited to 'module/zfs/zio_compress.c')
| -rw-r--r-- | module/zfs/zio_compress.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/module/zfs/zio_compress.c b/module/zfs/zio_compress.c new file mode 100644 index 000000000..c563be4eb --- /dev/null +++ b/module/zfs/zio_compress.c @@ -0,0 +1,148 @@ +/* + * 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. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#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)); +} |