kernel/fs/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  * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
  29  */
  30
  31 #include <sys/zfs_context.h>
  32 #include <sys/compress.h>
  33 #include <sys/spa.h>
  34 #include <sys/zfeature.h>
  35 #include <sys/zio.h>
  36 #include <sys/zio_compress.h>
  37
  38 /*
  39  * Compression vectors.
  40  */
  41 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  42         {"inherit",             0,      NULL,           NULL},
  43         {"on",                  0,      NULL,           NULL},
  44         {"uncompressed",        0,      NULL,           NULL},
  45         {"lzjb",                0,      lzjb_compress,  lzjb_decompress},
  46         {"empty",               0,      NULL,           NULL},
  47         {"gzip-1",              1,      gzip_compress,  gzip_decompress},
  48         {"gzip-2",              2,      gzip_compress,  gzip_decompress},
  49         {"gzip-3",              3,      gzip_compress,  gzip_decompress},
  50         {"gzip-4",              4,      gzip_compress,  gzip_decompress},
  51         {"gzip-5",              5,      gzip_compress,  gzip_decompress},
  52         {"gzip-6",              6,      gzip_compress,  gzip_decompress},
  53         {"gzip-7",              7,      gzip_compress,  gzip_decompress},
  54         {"gzip-8",              8,      gzip_compress,  gzip_decompress},
  55         {"gzip-9",              9,      gzip_compress,  gzip_decompress},
  56         {"zle",                 64,     zle_compress,   zle_decompress},
  57         {"lz4",                 0,      lz4_compress,   lz4_decompress}
  58 };
  59
  60 enum zio_compress
  61 zio_compress_select(spa_t *spa, enum zio_compress child,
  62     enum zio_compress parent)
  63 {
  64         enum zio_compress result;
  65
  66         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  67         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  68         ASSERT(parent != ZIO_COMPRESS_INHERIT);
  69
  70         result = child;
  71         if (result == ZIO_COMPRESS_INHERIT)
  72                 result = parent;
  73
  74         if (result == ZIO_COMPRESS_ON) {
  75                 if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
  76                         result = ZIO_COMPRESS_LZ4_ON_VALUE;
  77                 else
  78                         result = ZIO_COMPRESS_LEGACY_ON_VALUE;
  79         }
  80
  81         return (result);
  82 }
  83
  84 /*ARGSUSED*/
  85 static int
  86 zio_compress_zeroed_cb(void *data, size_t len, void *private)
  87 {
  88         uint64_t *end = (uint64_t *)((char *)data + len);
  89         for (uint64_t *word = (uint64_t *)data; word < end; word++)
  90                 if (*word != 0)
  91                         return (1);
  92
  93         return (0);
  94 }
  95
  96 size_t
  97 zio_compress_data(enum zio_compress c, abd_t *src, void *dst, size_t s_len)
  98 {
  99         size_t c_len, d_len;
 100         zio_compress_info_t *ci = &zio_compress_table[c];
 101
 102         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
 103         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
 104
 105         /*
 106          * If the data is all zeroes, we don't even need to allocate
 107          * a block for it.  We indicate this by returning zero size.
 108          */
 109         if (abd_iterate_func(src, 0, s_len, zio_compress_zeroed_cb, NULL) == 0)
 110                 return (0);
 111
 112         if (c == ZIO_COMPRESS_EMPTY)
 113                 return (s_len);
 114
 115         /* Compress at least 12.5% */
 116         d_len = s_len - (s_len >> 3);
 117
 118         /* No compression algorithms can read from ABDs directly */
 119         void *tmp = abd_borrow_buf_copy(src, s_len);
 120         c_len = ci->ci_compress(tmp, dst, s_len, d_len, ci->ci_level);
 121         abd_return_buf(src, tmp, s_len);
 122
 123         if (c_len > d_len)
 124                 return (s_len);
 125
 126         ASSERT3U(c_len, <=, d_len);
 127         return (c_len);
 128 }
 129
 130 int
 131 zio_decompress_data_buf(enum zio_compress c, void *src, void *dst,
 132     size_t s_len, size_t d_len)
 133 {
 134         zio_compress_info_t *ci = &zio_compress_table[c];
 135         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 136                 return (SET_ERROR(EINVAL));
 137
 138         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 139 }
 140
 141 int
 142 zio_decompress_data(enum zio_compress c, abd_t *src, void *dst,
 143     size_t s_len, size_t d_len)
 144 {
 145         void *tmp = abd_borrow_buf_copy(src, s_len);
 146         int ret = zio_decompress_data_buf(c, tmp, dst, s_len, d_len);
 147         abd_return_buf(src, tmp, s_len);
 148
 149         return (ret);
 150 }