module/zfs/zio_compress.c

   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/spa.h>
  37 #include <sys/zio.h>
  38 #include <sys/zio_compress.h>
  39
  40 /*
  41  * Compression vectors.
  42  */
  43
  44 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  45         {NULL,                  NULL,                   0,      "inherit"},
  46         {NULL,                  NULL,                   0,      "on"},
  47         {NULL,                  NULL,                   0,      "uncompressed"},
  48         {lzjb_compress,         lzjb_decompress,        0,      "lzjb"},
  49         {NULL,                  NULL,                   0,      "empty"},
  50         {gzip_compress,         gzip_decompress,        1,      "gzip-1"},
  51         {gzip_compress,         gzip_decompress,        2,      "gzip-2"},
  52         {gzip_compress,         gzip_decompress,        3,      "gzip-3"},
  53         {gzip_compress,         gzip_decompress,        4,      "gzip-4"},
  54         {gzip_compress,         gzip_decompress,        5,      "gzip-5"},
  55         {gzip_compress,         gzip_decompress,        6,      "gzip-6"},
  56         {gzip_compress,         gzip_decompress,        7,      "gzip-7"},
  57         {gzip_compress,         gzip_decompress,        8,      "gzip-8"},
  58         {gzip_compress,         gzip_decompress,        9,      "gzip-9"},
  59         {zle_compress,          zle_decompress,         64,     "zle"},
  60         {lz4_compress_zfs,      lz4_decompress_zfs,     0,      "lz4"},
  61 };
  62
  63 enum zio_compress
  64 zio_compress_select(enum zio_compress child, enum zio_compress parent)
  65 {
  66         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  67         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  68         ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
  69
  70         if (child == ZIO_COMPRESS_INHERIT)
  71                 return (parent);
  72
  73         if (child == ZIO_COMPRESS_ON)
  74                 return (ZIO_COMPRESS_ON_VALUE);
  75
  76         return (child);
  77 }
  78
  79 size_t
  80 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
  81 {
  82         uint64_t *word, *word_end;
  83         size_t c_len, d_len;
  84         zio_compress_info_t *ci = &zio_compress_table[c];
  85
  86         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
  87         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
  88
  89         /*
  90          * If the data is all zeroes, we don't even need to allocate
  91          * a block for it.  We indicate this by returning zero size.
  92          */
  93         word_end = (uint64_t *)((char *)src + s_len);
  94         for (word = src; word < word_end; word++)
  95                 if (*word != 0)
  96                         break;
  97
  98         if (word == word_end)
  99                 return (0);
 100
 101         if (c == ZIO_COMPRESS_EMPTY)
 102                 return (s_len);
 103
 104         /* Compress at least 12.5% */
 105         d_len = s_len - (s_len >> 3);
 106         c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
 107
 108         if (c_len > d_len)
 109                 return (s_len);
 110
 111         ASSERT3U(c_len, <=, d_len);
 112         return (c_len);
 113 }
 114
 115 int
 116 zio_decompress_data(enum zio_compress c, void *src, void *dst,
 117     size_t s_len, size_t d_len)
 118 {
 119         zio_compress_info_t *ci = &zio_compress_table[c];
 120
 121         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 122                 return (SET_ERROR(EINVAL));
 123
 124         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 125 }