include/zfs/spa.h

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /*
  20  * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
  21  */
  22
  23 #ifndef ZFS_SPA_HEADER
  24 #define ZFS_SPA_HEADER 1
  25
  26
  27 /*
  28  * General-purpose 32-bit and 64-bit bitfield encodings.
  29  */
  30 #define BF32_DECODE(x, low, len)        P2PHASE((x) >> (low), 1U << (len))
  31 #define BF64_DECODE(x, low, len)        P2PHASE((x) >> (low), 1ULL << (len))
  32 #define BF32_ENCODE(x, low, len)        (P2PHASE((x), 1U << (len)) << (low))
  33 #define BF64_ENCODE(x, low, len)        (P2PHASE((x), 1ULL << (len)) << (low))
  34
  35 #define BF32_GET(x, low, len)           BF32_DECODE(x, low, len)
  36 #define BF64_GET(x, low, len)           BF64_DECODE(x, low, len)
  37
  38 #define BF32_SET(x, low, len, val)                                              \
  39         ((x) ^= BF32_ENCODE((x >> low) ^ (val), low, len))
  40 #define BF64_SET(x, low, len, val)                                              \
  41         ((x) ^= BF64_ENCODE((x >> low) ^ (val), low, len))
  42
  43 #define BF32_GET_SB(x, low, len, shift, bias)           \
  44         ((BF32_GET(x, low, len) + (bias)) << (shift))
  45 #define BF64_GET_SB(x, low, len, shift, bias)           \
  46         ((BF64_GET(x, low, len) + (bias)) << (shift))
  47
  48 #define BF32_SET_SB(x, low, len, shift, bias, val)              \
  49         BF32_SET(x, low, len, ((val) >> (shift)) - (bias))
  50 #define BF64_SET_SB(x, low, len, shift, bias, val)              \
  51         BF64_SET(x, low, len, ((val) >> (shift)) - (bias))
  52
  53 /*
  54  * We currently support nine block sizes, from 512 bytes to 128K.
  55  * We could go higher, but the benefits are near-zero and the cost
  56  * of COWing a giant block to modify one byte would become excessive.
  57  */
  58 #define SPA_MINBLOCKSHIFT       9
  59 #define SPA_MAXBLOCKSHIFT       17
  60 #define SPA_MINBLOCKSIZE        (1ULL << SPA_MINBLOCKSHIFT)
  61 #define SPA_MAXBLOCKSIZE        (1ULL << SPA_MAXBLOCKSHIFT)
  62
  63 #define SPA_BLOCKSIZES          (SPA_MAXBLOCKSHIFT - SPA_MINBLOCKSHIFT + 1)
  64
  65 /*
  66  * Size of block to hold the configuration data (a packed nvlist)
  67  */
  68 #define SPA_CONFIG_BLOCKSIZE    (1 << 14)
  69
  70 /*
  71  * The DVA size encodings for LSIZE and PSIZE support blocks up to 32MB.
  72  * The ASIZE encoding should be at least 64 times larger (6 more bits)
  73  * to support up to 4-way RAID-Z mirror mode with worst-case gang block
  74  * overhead, three DVAs per bp, plus one more bit in case we do anything
  75  * else that expands the ASIZE.
  76  */
  77 #define SPA_LSIZEBITS           16      /* LSIZE up to 32M (2^16 * 512) */
  78 #define SPA_PSIZEBITS           16      /* PSIZE up to 32M (2^16 * 512) */
  79 #define SPA_ASIZEBITS           24      /* ASIZE up to 64 times larger  */
  80
  81 /*
  82  * All SPA data is represented by 128-bit data virtual addresses (DVAs).
  83  * The members of the dva_t should be considered opaque outside the SPA.
  84  */
  85 typedef struct dva {
  86         uint64_t        dva_word[2];
  87 } dva_t;
  88
  89 /*
  90  * Each block has a 256-bit checksum -- strong enough for cryptographic hashes.
  91  */
  92 typedef struct zio_cksum {
  93         uint64_t        zc_word[4];
  94 } zio_cksum_t;
  95
  96 /*
  97  * Each block is described by its DVAs, time of birth, checksum, etc.
  98  * The word-by-word, bit-by-bit layout of the blkptr is as follows:
  99  *
 100  *      64      56      48      40      32      24      16      8       0
 101  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 102  * 0    |               vdev1           | GRID  |         ASIZE         |
 103  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 104  * 1    |G|                      offset1                                |
 105  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 106  * 2    |               vdev2           | GRID  |         ASIZE         |
 107  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 108  * 3    |G|                      offset2                                |
 109  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 110  * 4    |               vdev3           | GRID  |         ASIZE         |
 111  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 112  * 5    |G|                      offset3                                |
 113  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 114  * 6    |BDX|lvl| type  | cksum | comp  |         PSIZE |         LSIZE |
 115  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 116  * 7    |                       padding                                 |
 117  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 118  * 8    |                       padding                                 |
 119  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 120  * 9    |                       physical birth txg                      |
 121  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 122  * a    |                       logical birth txg                       |
 123  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 124  * b    |                       fill count                              |
 125  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 126  * c    |                       checksum[0]                             |
 127  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 128  * d    |                       checksum[1]                             |
 129  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 130  * e    |                       checksum[2]                             |
 131  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 132  * f    |                       checksum[3]                             |
 133  *      +-------+-------+-------+-------+-------+-------+-------+-------+
 134  *
 135  * Legend:
 136  *
 137  * vdev         virtual device ID
 138  * offset       offset into virtual device
 139  * LSIZE        logical size
 140  * PSIZE        physical size (after compression)
 141  * ASIZE        allocated size (including RAID-Z parity and gang block headers)
 142  * GRID         RAID-Z layout information (reserved for future use)
 143  * cksum        checksum function
 144  * comp         compression function
 145  * G            gang block indicator
 146  * B            byteorder (endianness)
 147  * D            dedup
 148  * X            unused
 149  * lvl          level of indirection
 150  * type         DMU object type
 151  * phys birth   txg of block allocation; zero if same as logical birth txg
 152  * log. birth   transaction group in which the block was logically born
 153  * fill count   number of non-zero blocks under this bp
 154  * checksum[4]  256-bit checksum of the data this bp describes
 155  */
 156 #define SPA_BLKPTRSHIFT 7               /* blkptr_t is 128 bytes        */
 157 #define SPA_DVAS_PER_BP 3               /* Number of DVAs in a bp       */
 158
 159 typedef struct blkptr {
 160         dva_t           blk_dva[SPA_DVAS_PER_BP]; /* Data Virtual Addresses */
 161         uint64_t        blk_prop;       /* size, compression, type, etc         */
 162         uint64_t        blk_pad[2];     /* Extra space for the future           */
 163         uint64_t        blk_phys_birth; /* txg when block was allocated         */
 164         uint64_t        blk_birth;      /* transaction group at birth           */
 165         uint64_t        blk_fill;       /* fill count                           */
 166         zio_cksum_t     blk_cksum;      /* 256-bit checksum                     */
 167 } blkptr_t;
 168
 169 /*
 170  * Macros to get and set fields in a bp or DVA.
 171  */
 172 #define DVA_GET_ASIZE(dva)                                                                                      \
 173         BF64_GET_SB((dva)->dva_word[0], 0, 24, SPA_MINBLOCKSHIFT, 0)
 174 #define DVA_SET_ASIZE(dva, x)                                                                           \
 175         BF64_SET_SB((dva)->dva_word[0], 0, 24, SPA_MINBLOCKSHIFT, 0, x)
 176
 177 #define DVA_GET_GRID(dva)       BF64_GET((dva)->dva_word[0], 24, 8)
 178 #define DVA_SET_GRID(dva, x)    BF64_SET((dva)->dva_word[0], 24, 8, x)
 179
 180 #define DVA_GET_VDEV(dva)       BF64_GET((dva)->dva_word[0], 32, 32)
 181 #define DVA_SET_VDEV(dva, x)    BF64_SET((dva)->dva_word[0], 32, 32, x)
 182
 183 #define DVA_GET_GANG(dva)       BF64_GET((dva)->dva_word[1], 63, 1)
 184 #define DVA_SET_GANG(dva, x)    BF64_SET((dva)->dva_word[1], 63, 1, x)
 185
 186 #define BP_GET_LSIZE(bp)                                                                                \
 187         BF64_GET_SB((bp)->blk_prop, 0, 16, SPA_MINBLOCKSHIFT, 1)
 188 #define BP_SET_LSIZE(bp, x)                                                                             \
 189         BF64_SET_SB((bp)->blk_prop, 0, 16, SPA_MINBLOCKSHIFT, 1, x)
 190
 191 #define BP_GET_COMPRESS(bp)             BF64_GET((bp)->blk_prop, 32, 8)
 192 #define BP_SET_COMPRESS(bp, x)          BF64_SET((bp)->blk_prop, 32, 8, x)
 193
 194 #define BP_GET_CHECKSUM(bp)             BF64_GET((bp)->blk_prop, 40, 8)
 195 #define BP_SET_CHECKSUM(bp, x)          BF64_SET((bp)->blk_prop, 40, 8, x)
 196
 197 #define BP_GET_TYPE(bp)                 BF64_GET((bp)->blk_prop, 48, 8)
 198 #define BP_SET_TYPE(bp, x)              BF64_SET((bp)->blk_prop, 48, 8, x)
 199
 200 #define BP_GET_LEVEL(bp)                BF64_GET((bp)->blk_prop, 56, 5)
 201 #define BP_SET_LEVEL(bp, x)             BF64_SET((bp)->blk_prop, 56, 5, x)
 202
 203 #define BP_GET_PROP_BIT_61(bp)          BF64_GET((bp)->blk_prop, 61, 1)
 204 #define BP_SET_PROP_BIT_61(bp, x)       BF64_SET((bp)->blk_prop, 61, 1, x)
 205
 206 #define BP_GET_DEDUP(bp)                BF64_GET((bp)->blk_prop, 62, 1)
 207 #define BP_SET_DEDUP(bp, x)             BF64_SET((bp)->blk_prop, 62, 1, x)
 208
 209 #define BP_GET_BYTEORDER(bp)            (0 - BF64_GET((bp)->blk_prop, 63, 1))
 210 #define BP_SET_BYTEORDER(bp, x)         BF64_SET((bp)->blk_prop, 63, 1, x)
 211
 212 #define BP_PHYSICAL_BIRTH(bp)                                                                           \
 213         ((bp)->blk_phys_birth ? (bp)->blk_phys_birth : (bp)->blk_birth)
 214
 215 #define BP_SET_BIRTH(bp, logical, physical)                                                             \
 216         {                                                                                                                                       \
 217                 (bp)->blk_birth = (logical);                                                                    \
 218                 (bp)->blk_phys_birth = ((logical) == (physical) ? 0 : (physical)); \
 219         }
 220
 221 #define BP_GET_ASIZE(bp)                                                                                                \
 222         (DVA_GET_ASIZE(&(bp)->blk_dva[0]) + DVA_GET_ASIZE(&(bp)->blk_dva[1]) + \
 223          DVA_GET_ASIZE(&(bp)->blk_dva[2]))
 224
 225 #define BP_GET_UCSIZE(bp)                                                                                               \
 226         ((BP_GET_LEVEL(bp) > 0 || dmu_ot[BP_GET_TYPE(bp)].ot_metadata) ?        \
 227          BP_GET_PSIZE(bp) : BP_GET_LSIZE(bp));
 228
 229 #define BP_GET_NDVAS(bp)                                                \
 230         (!!DVA_GET_ASIZE(&(bp)->blk_dva[0]) +           \
 231          !!DVA_GET_ASIZE(&(bp)->blk_dva[1]) +           \
 232          !!DVA_GET_ASIZE(&(bp)->blk_dva[2]))
 233
 234 #define BP_COUNT_GANG(bp)                                               \
 235         (DVA_GET_GANG(&(bp)->blk_dva[0]) +                      \
 236          DVA_GET_GANG(&(bp)->blk_dva[1]) +                      \
 237          DVA_GET_GANG(&(bp)->blk_dva[2]))
 238
 239 #define DVA_EQUAL(dva1, dva2)                                           \
 240         ((dva1)->dva_word[1] == (dva2)->dva_word[1] &&  \
 241          (dva1)->dva_word[0] == (dva2)->dva_word[0])
 242
 243 #define BP_EQUAL(bp1, bp2)                                                                      \
 244         (BP_PHYSICAL_BIRTH(bp1) == BP_PHYSICAL_BIRTH(bp2) &&    \
 245          DVA_EQUAL(&(bp1)->blk_dva[0], &(bp2)->blk_dva[0]) &&   \
 246          DVA_EQUAL(&(bp1)->blk_dva[1], &(bp2)->blk_dva[1]) &&   \
 247          DVA_EQUAL(&(bp1)->blk_dva[2], &(bp2)->blk_dva[2]))
 248
 249 #define ZIO_CHECKSUM_EQUAL(zc1, zc2)                            \
 250         (0 == (((zc1).zc_word[0] - (zc2).zc_word[0]) |  \
 251                    ((zc1).zc_word[1] - (zc2).zc_word[1]) |      \
 252                    ((zc1).zc_word[2] - (zc2).zc_word[2]) |      \
 253                    ((zc1).zc_word[3] - (zc2).zc_word[3])))
 254
 255 #define DVA_IS_VALID(dva)       (DVA_GET_ASIZE(dva) != 0)
 256
 257 #define ZIO_SET_CHECKSUM(zcp, w0, w1, w2, w3)   \
 258         {                                                                                       \
 259                 (zcp)->zc_word[0] = w0;                                 \
 260                 (zcp)->zc_word[1] = w1;                                 \
 261                 (zcp)->zc_word[2] = w2;                                 \
 262                 (zcp)->zc_word[3] = w3;                                 \
 263         }
 264
 265 #define BP_IDENTITY(bp)         (&(bp)->blk_dva[0])
 266 #define BP_IS_GANG(bp)          DVA_GET_GANG(BP_IDENTITY(bp))
 267 #define BP_IS_HOLE(bp)          ((bp)->blk_birth == 0)
 268
 269 /* BP_IS_RAIDZ(bp) assumes no block compression */
 270 #define BP_IS_RAIDZ(bp)         (DVA_GET_ASIZE(&(bp)->blk_dva[0]) > \
 271                                                          BP_GET_PSIZE(bp))
 272
 273 #define BP_ZERO(bp)                                                                             \
 274         {                                                                                                       \
 275                 (bp)->blk_dva[0].dva_word[0] = 0;                               \
 276                 (bp)->blk_dva[0].dva_word[1] = 0;                               \
 277                 (bp)->blk_dva[1].dva_word[0] = 0;                               \
 278                 (bp)->blk_dva[1].dva_word[1] = 0;                               \
 279                 (bp)->blk_dva[2].dva_word[0] = 0;                               \
 280                 (bp)->blk_dva[2].dva_word[1] = 0;                               \
 281                 (bp)->blk_prop = 0;                                                             \
 282                 (bp)->blk_pad[0] = 0;                                                   \
 283                 (bp)->blk_pad[1] = 0;                                                   \
 284                 (bp)->blk_phys_birth = 0;                                               \
 285                 (bp)->blk_birth = 0;                                                    \
 286                 (bp)->blk_fill = 0;                                                             \
 287                 ZIO_SET_CHECKSUM(&(bp)->blk_cksum, 0, 0, 0, 0); \
 288         }
 289
 290 #define BP_SPRINTF_LEN  320
 291
 292 #endif  /* ! ZFS_SPA_HEADER */