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, 2016 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 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  45         {"inherit",             0,      NULL,           NULL},
  46         {"on",                  0,      NULL,           NULL},
  47         {"uncompressed",        0,      NULL,           NULL},
  48         {"lzjb",                0,      lzjb_compress,  lzjb_decompress},
  49         {"empty",               0,      NULL,           NULL},
  50         {"gzip-1",              1,      gzip_compress,  gzip_decompress},
  51         {"gzip-2",              2,      gzip_compress,  gzip_decompress},
  52         {"gzip-3",              3,      gzip_compress,  gzip_decompress},
  53         {"gzip-4",              4,      gzip_compress,  gzip_decompress},
  54         {"gzip-5",              5,      gzip_compress,  gzip_decompress},
  55         {"gzip-6",              6,      gzip_compress,  gzip_decompress},
  56         {"gzip-7",              7,      gzip_compress,  gzip_decompress},
  57         {"gzip-8",              8,      gzip_compress,  gzip_decompress},
  58         {"gzip-9",              9,      gzip_compress,  gzip_decompress},
  59         {"zle",                 64,     zle_compress,   zle_decompress},
  60         {"lz4",                 0,      lz4_compress_zfs, lz4_decompress_zfs}
  61 };
  62
  63 enum zio_compress
  64 zio_compress_select(spa_t *spa, enum zio_compress child,
  65     enum zio_compress parent)
  66 {
  67         enum zio_compress result;
  68
  69         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  70         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  71         ASSERT(parent != ZIO_COMPRESS_INHERIT);
  72
  73         result = child;
  74         if (result == ZIO_COMPRESS_INHERIT)
  75                 result = parent;
  76
  77         if (result == ZIO_COMPRESS_ON) {
  78                 if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
  79                         result = ZIO_COMPRESS_LZ4_ON_VALUE;
  80                 else
  81                         result = ZIO_COMPRESS_LEGACY_ON_VALUE;
  82         }
  83
  84         return (result);
  85 }
  86
  87 /*ARGSUSED*/
  88 static int
  89 zio_compress_zeroed_cb(void *data, size_t len, void *private)
  90 {
  91         uint64_t *end = (uint64_t *)((char *)data + len);
  92         for (uint64_t *word = (uint64_t *)data; word < end; word++)
  93                 if (*word != 0)
  94                         return (1);
  95
  96         return (0);
  97 }
  98
  99 size_t
 100 zio_compress_data(enum zio_compress c, abd_t *src, void *dst, size_t s_len)
 101 {
 102         size_t c_len, d_len;
 103         zio_compress_info_t *ci = &zio_compress_table[c];
 104
 105         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
 106         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
 107
 108         /*
 109          * If the data is all zeroes, we don't even need to allocate
 110          * a block for it.  We indicate this by returning zero size.
 111          */
 112         if (abd_iterate_func(src, 0, s_len, zio_compress_zeroed_cb, NULL) == 0)
 113                 return (0);
 114
 115         if (c == ZIO_COMPRESS_EMPTY)
 116                 return (s_len);
 117
 118         /* Compress at least 12.5% */
 119         d_len = s_len - (s_len >> 3);
 120
 121         /* No compression algorithms can read from ABDs directly */
 122         void *tmp = abd_borrow_buf_copy(src, s_len);
 123         c_len = ci->ci_compress(tmp, dst, s_len, d_len, ci->ci_level);
 124         abd_return_buf(src, tmp, s_len);
 125
 126         if (c_len > d_len)
 127                 return (s_len);
 128
 129         ASSERT3U(c_len, <=, d_len);
 130         return (c_len);
 131 }
 132
 133 int
 134 zio_decompress_data_buf(enum zio_compress c, void *src, void *dst,
 135     size_t s_len, size_t d_len)
 136 {
 137         zio_compress_info_t *ci = &zio_compress_table[c];
 138         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 139                 return (SET_ERROR(EINVAL));
 140
 141         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 142 }
 143
 144 int
 145 zio_decompress_data(enum zio_compress c, abd_t *src, void *dst,
 146     size_t s_len, size_t d_len)
 147 {
 148         void *tmp = abd_borrow_buf_copy(src, s_len);
 149         int ret = zio_decompress_data_buf(c, tmp, dst, s_len, d_len);
 150         abd_return_buf(src, tmp, s_len);
 151
 152         return (ret);
 153 }