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 #include <sys/zfs_context.h>
  31 #include <sys/compress.h>
  32 #include <sys/spa.h>
  33 #include <sys/zio.h>
  34 #include <sys/zio_compress.h>
  35 
  36 /*
  37  * Compression vectors.
  38  */
  39 
  40 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  41         {NULL,                  NULL,                   0,      "inherit"},
  42         {NULL,                  NULL,                   0,      "on"},
  43         {NULL,                  NULL,                   0,      "uncompressed"},
  44         {lzjb_compress,         lzjb_decompress,        0,      "lzjb"},
  45         {NULL,                  NULL,                   0,      "empty"},
  46         {gzip_compress,         gzip_decompress,        1,      "gzip-1"},
  47         {gzip_compress,         gzip_decompress,        2,      "gzip-2"},
  48         {gzip_compress,         gzip_decompress,        3,      "gzip-3"},
  49         {gzip_compress,         gzip_decompress,        4,      "gzip-4"},
  50         {gzip_compress,         gzip_decompress,        5,      "gzip-5"},
  51         {gzip_compress,         gzip_decompress,        6,      "gzip-6"},
  52         {gzip_compress,         gzip_decompress,        7,      "gzip-7"},
  53         {gzip_compress,         gzip_decompress,        8,      "gzip-8"},
  54         {gzip_compress,         gzip_decompress,        9,      "gzip-9"},
  55         {zle_compress,          zle_decompress,         64,     "zle"},
  56         {lz4_compress,          lz4_decompress,         0,      "lz4"},
  57         {lz4_compress,          lz4_decompress,         1,      "lz4hc"},
  58 };
  59 
  60 enum zio_compress
  61 zio_compress_select(enum zio_compress child, enum zio_compress parent)
  62 {
  63         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  64         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  65         ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
  66 
  67         if (child == ZIO_COMPRESS_INHERIT)
  68                 return (parent);
  69 
  70         if (child == ZIO_COMPRESS_ON)
  71                 return (ZIO_COMPRESS_ON_VALUE);
  72 
  73         return (child);
  74 }
  75 
  76 size_t
  77 zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
  78 {
  79         uint64_t *word, *word_end;
  80         size_t c_len, d_len, r_len;
  81         zio_compress_info_t *ci = &zio_compress_table[c];
  82 
  83         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
  84         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
  85 
  86         /*
  87          * If the data is all zeroes, we don't even need to allocate
  88          * a block for it.  We indicate this by returning zero size.
  89          */
  90         word_end = (uint64_t *)((char *)src + s_len);
  91         for (word = src; word < word_end; word++)
  92                 if (*word != 0)
  93                         break;
  94 
  95         if (word == word_end)
  96                 return (0);
  97 
  98         if (c == ZIO_COMPRESS_EMPTY)
  99                 return (s_len);
 100 
 101         /* Compress at least 12.5% */
 102         d_len = P2ALIGN(s_len - (s_len >> 3), (size_t)SPA_MINBLOCKSIZE);
 103         if (d_len == 0)
 104                 return (s_len);
 105 
 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         /*
 112          * Cool.  We compressed at least as much as we were hoping to.
 113          * For both security and repeatability, pad out the last sector.
 114          */
 115         r_len = P2ROUNDUP(c_len, (size_t)SPA_MINBLOCKSIZE);
 116         if (r_len > c_len) {
 117                 bzero((char *)dst + c_len, r_len - c_len);
 118                 c_len = r_len;
 119         }
 120 
 121         ASSERT3U(c_len, <=, d_len);
 122         ASSERT(P2PHASE(c_len, (size_t)SPA_MINBLOCKSIZE) == 0);
 123 
 124         return (c_len);
 125 }
 126 
 127 int
 128 zio_decompress_data(enum zio_compress c, void *src, void *dst,
 129     size_t s_len, size_t d_len)
 130 {
 131         zio_compress_info_t *ci = &zio_compress_table[c];
 132 
 133         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 134                 return (EINVAL);
 135 
 136         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 137 }