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 https://opensource.org/licenses/CDDL-1.0.
  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, 2018 by Delphix. All rights reserved.
  32  * Copyright (c) 2019, Klara Inc.
  33  * Copyright (c) 2019, Allan Jude
  34  */
  35
  36 #include <sys/zfs_context.h>
  37 #include <sys/spa.h>
  38 #include <sys/zfeature.h>
  39 #include <sys/zio.h>
  40 #include <sys/zio_compress.h>
  41 #include <sys/zstd/zstd.h>
  42
  43 /*
  44  * If nonzero, every 1/X decompression attempts will fail, simulating
  45  * an undetected memory error.
  46  */
  47 static unsigned long zio_decompress_fail_fraction = 0;
  48
  49 /*
  50  * Compression vectors.
  51  */
  52 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  53         {"inherit",     0,      NULL,           NULL, NULL},
  54         {"on",          0,      NULL,           NULL, NULL},
  55         {"uncompressed", 0,     NULL,           NULL, NULL},
  56         {"lzjb",        0,      lzjb_compress,  lzjb_decompress, NULL},
  57         {"empty",       0,      NULL,           NULL, NULL},
  58         {"gzip-1",      1,      gzip_compress,  gzip_decompress, NULL},
  59         {"gzip-2",      2,      gzip_compress,  gzip_decompress, NULL},
  60         {"gzip-3",      3,      gzip_compress,  gzip_decompress, NULL},
  61         {"gzip-4",      4,      gzip_compress,  gzip_decompress, NULL},
  62         {"gzip-5",      5,      gzip_compress,  gzip_decompress, NULL},
  63         {"gzip-6",      6,      gzip_compress,  gzip_decompress, NULL},
  64         {"gzip-7",      7,      gzip_compress,  gzip_decompress, NULL},
  65         {"gzip-8",      8,      gzip_compress,  gzip_decompress, NULL},
  66         {"gzip-9",      9,      gzip_compress,  gzip_decompress, NULL},
  67         {"zle",         64,     zle_compress,   zle_decompress, NULL},
  68         {"lz4",         0,      lz4_compress_zfs, lz4_decompress_zfs, NULL},
  69         {"zstd",        ZIO_ZSTD_LEVEL_DEFAULT, zfs_zstd_compress_wrap,
  70             zfs_zstd_decompress, zfs_zstd_decompress_level},
  71 };
  72
  73 uint8_t
  74 zio_complevel_select(spa_t *spa, enum zio_compress compress, uint8_t child,
  75     uint8_t parent)
  76 {
  77         (void) spa;
  78         uint8_t result;
  79
  80         if (!ZIO_COMPRESS_HASLEVEL(compress))
  81                 return (0);
  82
  83         result = child;
  84         if (result == ZIO_COMPLEVEL_INHERIT)
  85                 result = parent;
  86
  87         return (result);
  88 }
  89
  90 enum zio_compress
  91 zio_compress_select(spa_t *spa, enum zio_compress child,
  92     enum zio_compress parent)
  93 {
  94         enum zio_compress result;
  95
  96         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  97         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  98         ASSERT(parent != ZIO_COMPRESS_INHERIT);
  99
 100         result = child;
 101         if (result == ZIO_COMPRESS_INHERIT)
 102                 result = parent;
 103
 104         if (result == ZIO_COMPRESS_ON) {
 105                 if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
 106                         result = ZIO_COMPRESS_LZ4_ON_VALUE;
 107                 else
 108                         result = ZIO_COMPRESS_LEGACY_ON_VALUE;
 109         }
 110
 111         return (result);
 112 }
 113
 114 static int
 115 zio_compress_zeroed_cb(void *data, size_t len, void *private)
 116 {
 117         (void) private;
 118
 119         uint64_t *end = (uint64_t *)((char *)data + len);
 120         for (uint64_t *word = (uint64_t *)data; word < end; word++)
 121                 if (*word != 0)
 122                         return (1);
 123
 124         return (0);
 125 }
 126
 127 size_t
 128 zio_compress_data(enum zio_compress c, abd_t *src, void **dst, size_t s_len,
 129     uint8_t level)
 130 {
 131         size_t c_len, d_len;
 132         uint8_t complevel;
 133         zio_compress_info_t *ci = &zio_compress_table[c];
 134
 135         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
 136         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
 137
 138         /*
 139          * If the data is all zeroes, we don't even need to allocate
 140          * a block for it.  We indicate this by returning zero size.
 141          */
 142         if (abd_iterate_func(src, 0, s_len, zio_compress_zeroed_cb, NULL) == 0)
 143                 return (0);
 144
 145         if (c == ZIO_COMPRESS_EMPTY)
 146                 return (s_len);
 147
 148         /* Compress at least 12.5% */
 149         d_len = s_len - (s_len >> 3);
 150
 151         complevel = ci->ci_level;
 152
 153         if (c == ZIO_COMPRESS_ZSTD) {
 154                 /* If we don't know the level, we can't compress it */
 155                 if (level == ZIO_COMPLEVEL_INHERIT)
 156                         return (s_len);
 157
 158                 if (level == ZIO_COMPLEVEL_DEFAULT)
 159                         complevel = ZIO_ZSTD_LEVEL_DEFAULT;
 160                 else
 161                         complevel = level;
 162
 163                 ASSERT3U(complevel, !=, ZIO_COMPLEVEL_INHERIT);
 164         }
 165
 166         if (*dst == NULL)
 167                 *dst = zio_buf_alloc(s_len);
 168
 169         /* No compression algorithms can read from ABDs directly */
 170         void *tmp = abd_borrow_buf_copy(src, s_len);
 171         c_len = ci->ci_compress(tmp, *dst, s_len, d_len, complevel);
 172         abd_return_buf(src, tmp, s_len);
 173
 174         if (c_len > d_len)
 175                 return (s_len);
 176
 177         ASSERT3U(c_len, <=, d_len);
 178         return (c_len);
 179 }
 180
 181 int
 182 zio_decompress_data_buf(enum zio_compress c, void *src, void *dst,
 183     size_t s_len, size_t d_len, uint8_t *level)
 184 {
 185         zio_compress_info_t *ci = &zio_compress_table[c];
 186         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 187                 return (SET_ERROR(EINVAL));
 188
 189         if (ci->ci_decompress_level != NULL && level != NULL)
 190                 return (ci->ci_decompress_level(src, dst, s_len, d_len, level));
 191
 192         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 193 }
 194
 195 int
 196 zio_decompress_data(enum zio_compress c, abd_t *src, void *dst,
 197     size_t s_len, size_t d_len, uint8_t *level)
 198 {
 199         void *tmp = abd_borrow_buf_copy(src, s_len);
 200         int ret = zio_decompress_data_buf(c, tmp, dst, s_len, d_len, level);
 201         abd_return_buf(src, tmp, s_len);
 202
 203         /*
 204          * Decompression shouldn't fail, because we've already verified
 205          * the checksum.  However, for extra protection (e.g. against bitflips
 206          * in non-ECC RAM), we handle this error (and test it).
 207          */
 208         if (zio_decompress_fail_fraction != 0 &&
 209             random_in_range(zio_decompress_fail_fraction) == 0)
 210                 ret = SET_ERROR(EINVAL);
 211
 212         return (ret);
 213 }
 214
 215 int
 216 zio_compress_to_feature(enum zio_compress comp)
 217 {
 218         switch (comp) {
 219         case ZIO_COMPRESS_ZSTD:
 220                 return (SPA_FEATURE_ZSTD_COMPRESS);
 221         default:
 222                 break;
 223         }
 224         return (SPA_FEATURE_NONE);
 225 }