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/zfeature.h>
  38 #include <sys/zio.h>
  39 #include <sys/zio_compress.h>
  40
  41 /*
  42  * Compression vectors.
  43  */
  44
  45 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  46         {NULL,                  NULL,                   0,      "inherit"},
  47         {NULL,                  NULL,                   0,      "on"},
  48         {NULL,                  NULL,                   0,      "uncompressed"},
  49         {lzjb_compress,         lzjb_decompress,        0,      "lzjb"},
  50         {NULL,                  NULL,                   0,      "empty"},
  51         {gzip_compress,         gzip_decompress,        1,      "gzip-1"},
  52         {gzip_compress,         gzip_decompress,        2,      "gzip-2"},
  53         {gzip_compress,         gzip_decompress,        3,      "gzip-3"},
  54         {gzip_compress,         gzip_decompress,        4,      "gzip-4"},
  55         {gzip_compress,         gzip_decompress,        5,      "gzip-5"},
  56         {gzip_compress,         gzip_decompress,        6,      "gzip-6"},
  57         {gzip_compress,         gzip_decompress,        7,      "gzip-7"},
  58         {gzip_compress,         gzip_decompress,        8,      "gzip-8"},
  59         {gzip_compress,         gzip_decompress,        9,      "gzip-9"},
  60         {zle_compress,          zle_decompress,         64,     "zle"},
  61         {lz4_compress_zfs,      lz4_decompress_zfs,     0,      "lz4"},
  62 };
  63
  64 enum zio_compress
  65 zio_compress_select(spa_t *spa, enum zio_compress child,
  66     enum zio_compress parent)
  67 {
  68         enum zio_compress result;
  69
  70         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  71         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  72         ASSERT(parent != ZIO_COMPRESS_INHERIT);
  73
  74         result = child;
  75         if (result == ZIO_COMPRESS_INHERIT)
  76                 result = parent;
  77
  78         if (result == ZIO_COMPRESS_ON) {
  79                 if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
  80                         result = ZIO_COMPRESS_LZ4_ON_VALUE;
  81                 else
  82                         result = ZIO_COMPRESS_LEGACY_ON_VALUE;
  83         }
  84
  85         return (result);
  86 }
  87
  88 size_t
  89 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
  90 {
  91         uint64_t *word, *word_end;
  92         size_t c_len, d_len;
  93         zio_compress_info_t *ci = &zio_compress_table[c];
  94
  95         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
  96         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
  97
  98         /*
  99          * If the data is all zeroes, we don't even need to allocate
 100          * a block for it.  We indicate this by returning zero size.
 101          */
 102         word_end = (uint64_t *)((char *)src + s_len);
 103         for (word = src; word < word_end; word++)
 104                 if (*word != 0)
 105                         break;
 106
 107         if (word == word_end)
 108                 return (0);
 109
 110         if (c == ZIO_COMPRESS_EMPTY)
 111                 return (s_len);
 112
 113         /* Compress at least 12.5% */
 114         d_len = s_len - (s_len >> 3);
 115         c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
 116
 117         if (c_len > d_len)
 118                 return (s_len);
 119
 120         ASSERT3U(c_len, <=, d_len);
 121         return (c_len);
 122 }
 123
 124 int
 125 zio_decompress_data(enum zio_compress c, void *src, void *dst,
 126     size_t s_len, size_t d_len)
 127 {
 128         zio_compress_info_t *ci = &zio_compress_table[c];
 129
 130         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 131                 return (SET_ERROR(EINVAL));
 132
 133         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 134 }