loader: zfs should support bootonce an nextboot

[FreeBSD/FreeBSD.git] / sys / cddl / boot / zfs / zfsimpl.h

/*-
 * Copyright (c) 2002 McAfee, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Marshall
 * Kirk McKusick and McAfee Research,, the Security Research Division of
 * McAfee, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as
 * part of the DARPA CHATS research program
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright 2013 by Saso Kiselkov. All rights reserved.
 */
/*
 * Copyright (c) 2020 by Delphix. All rights reserved.
 */

#include <sys/queue.h>
#include <sys/list.h>
#include <bootstrap.h>

#ifndef _ZFSIMPL_H_
#define _ZFSIMPL_H_

#define MAXNAMELEN      256

#define _NOTE(s)

/*
 * AVL comparator helpers
 */
#define AVL_ISIGN(a)    (((a) > 0) - ((a) < 0))
#define AVL_CMP(a, b)   (((a) > (b)) - ((a) < (b)))
#define AVL_PCMP(a, b)  \
        (((uintptr_t)(a) > (uintptr_t)(b)) - ((uintptr_t)(a) < (uintptr_t)(b)))

typedef enum { B_FALSE, B_TRUE } boolean_t;

/* CRC64 table */
#define ZFS_CRC64_POLY  0xC96C5795D7870F42ULL   /* ECMA-182, reflected form */

/*
 * Macros for various sorts of alignment and rounding when the alignment
 * is known to be a power of 2.
 */
#define P2ALIGN(x, align)               ((x) & -(align))
#define P2PHASE(x, align)               ((x) & ((align) - 1))
#define P2NPHASE(x, align)              (-(x) & ((align) - 1))
#define P2ROUNDUP(x, align)             (-(-(x) & -(align)))
#define P2END(x, align)                 (-(~(x) & -(align)))
#define P2PHASEUP(x, align, phase)      ((phase) - (((phase) - (x)) & -(align)))
#define P2BOUNDARY(off, len, align)     (((off) ^ ((off) + (len) - 1)) > (align) - 1)

/*
 * General-purpose 32-bit and 64-bit bitfield encodings.
 */
#define BF32_DECODE(x, low, len)        P2PHASE((x) >> (low), 1U << (len))
#define BF64_DECODE(x, low, len)        P2PHASE((x) >> (low), 1ULL << (len))
#define BF32_ENCODE(x, low, len)        (P2PHASE((x), 1U << (len)) << (low))
#define BF64_ENCODE(x, low, len)        (P2PHASE((x), 1ULL << (len)) << (low))

#define BF32_GET(x, low, len)           BF32_DECODE(x, low, len)
#define BF64_GET(x, low, len)           BF64_DECODE(x, low, len)

#define BF32_SET(x, low, len, val)      \
        ((x) ^= BF32_ENCODE((x >> low) ^ (val), low, len))
#define BF64_SET(x, low, len, val)      \
        ((x) ^= BF64_ENCODE((x >> low) ^ (val), low, len))

#define BF32_GET_SB(x, low, len, shift, bias)   \
        ((BF32_GET(x, low, len) + (bias)) << (shift))
#define BF64_GET_SB(x, low, len, shift, bias)   \
        ((BF64_GET(x, low, len) + (bias)) << (shift))

#define BF32_SET_SB(x, low, len, shift, bias, val)      \
        BF32_SET(x, low, len, ((val) >> (shift)) - (bias))
#define BF64_SET_SB(x, low, len, shift, bias, val)      \
        BF64_SET(x, low, len, ((val) >> (shift)) - (bias))

/*
 * Macros to reverse byte order
 */
#define BSWAP_8(x)      ((x) & 0xff)
#define BSWAP_16(x)     ((BSWAP_8(x) << 8) | BSWAP_8((x) >> 8))
#define BSWAP_32(x)     ((BSWAP_16(x) << 16) | BSWAP_16((x) >> 16))
#define BSWAP_64(x)     ((BSWAP_32(x) << 32) | BSWAP_32((x) >> 32))

#define SPA_MINBLOCKSHIFT       9
#define SPA_OLDMAXBLOCKSHIFT    17
#define SPA_MAXBLOCKSHIFT       24
#define SPA_MINBLOCKSIZE        (1ULL << SPA_MINBLOCKSHIFT)
#define SPA_OLDMAXBLOCKSIZE     (1ULL << SPA_OLDMAXBLOCKSHIFT)
#define SPA_MAXBLOCKSIZE        (1ULL << SPA_MAXBLOCKSHIFT)

/*
 * The DVA size encodings for LSIZE and PSIZE support blocks up to 32MB.
 * The ASIZE encoding should be at least 64 times larger (6 more bits)
 * to support up to 4-way RAID-Z mirror mode with worst-case gang block
 * overhead, three DVAs per bp, plus one more bit in case we do anything
 * else that expands the ASIZE.
 */
#define SPA_LSIZEBITS           16      /* LSIZE up to 32M (2^16 * 512) */
#define SPA_PSIZEBITS           16      /* PSIZE up to 32M (2^16 * 512) */
#define SPA_ASIZEBITS           24      /* ASIZE up to 64 times larger  */

/*
 * All SPA data is represented by 128-bit data virtual addresses (DVAs).
 * The members of the dva_t should be considered opaque outside the SPA.
 */
typedef struct dva {
        uint64_t        dva_word[2];
} dva_t;

/*
 * Each block has a 256-bit checksum -- strong enough for cryptographic hashes.
 */
typedef struct zio_cksum {
        uint64_t        zc_word[4];
} zio_cksum_t;

/*
 * Some checksums/hashes need a 256-bit initialization salt. This salt is kept
 * secret and is suitable for use in MAC algorithms as the key.
 */
typedef struct zio_cksum_salt {
        uint8_t         zcs_bytes[32];
} zio_cksum_salt_t;

/*
 * Each block is described by its DVAs, time of birth, checksum, etc.
 * The word-by-word, bit-by-bit layout of the blkptr is as follows:
 *
 *      64      56      48      40      32      24      16      8       0
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 0    |               vdev1           | GRID  |         ASIZE         |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 1    |G|                      offset1                                |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 2    |               vdev2           | GRID  |         ASIZE         |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 3    |G|                      offset2                                |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 4    |               vdev3           | GRID  |         ASIZE         |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 5    |G|                      offset3                                |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 6    |BDX|lvl| type  | cksum |E| comp|    PSIZE      |     LSIZE     |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 7    |                       padding                                 |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 8    |                       padding                                 |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 9    |                       physical birth txg                      |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * a    |                       logical birth txg                       |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * b    |                       fill count                              |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * c    |                       checksum[0]                             |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * d    |                       checksum[1]                             |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * e    |                       checksum[2]                             |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * f    |                       checksum[3]                             |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 *
 * Legend:
 *
 * vdev         virtual device ID
 * offset       offset into virtual device
 * LSIZE        logical size
 * PSIZE        physical size (after compression)
 * ASIZE        allocated size (including RAID-Z parity and gang block headers)
 * GRID         RAID-Z layout information (reserved for future use)
 * cksum        checksum function
 * comp         compression function
 * G            gang block indicator
 * B            byteorder (endianness)
 * D            dedup
 * X            encryption (on version 30, which is not supported)
 * E            blkptr_t contains embedded data (see below)
 * lvl          level of indirection
 * type         DMU object type
 * phys birth   txg of block allocation; zero if same as logical birth txg
 * log. birth   transaction group in which the block was logically born
 * fill count   number of non-zero blocks under this bp
 * checksum[4]  256-bit checksum of the data this bp describes
 */

/*
 * "Embedded" blkptr_t's don't actually point to a block, instead they
 * have a data payload embedded in the blkptr_t itself.  See the comment
 * in blkptr.c for more details.
 *
 * The blkptr_t is laid out as follows:
 *
 *      64      56      48      40      32      24      16      8       0
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 0    |      payload                                                  |
 * 1    |      payload                                                  |
 * 2    |      payload                                                  |
 * 3    |      payload                                                  |
 * 4    |      payload                                                  |
 * 5    |      payload                                                  |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 6    |BDX|lvl| type  | etype |E| comp| PSIZE|              LSIZE     |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * 7    |      payload                                                  |
 * 8    |      payload                                                  |
 * 9    |      payload                                                  |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * a    |                       logical birth txg                       |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 * b    |      payload                                                  |
 * c    |      payload                                                  |
 * d    |      payload                                                  |
 * e    |      payload                                                  |
 * f    |      payload                                                  |
 *      +-------+-------+-------+-------+-------+-------+-------+-------+
 *
 * Legend:
 *
 * payload              contains the embedded data
 * B (byteorder)        byteorder (endianness)
 * D (dedup)            padding (set to zero)
 * X                    encryption (set to zero; see above)
 * E (embedded)         set to one
 * lvl                  indirection level
 * type                 DMU object type
 * etype                how to interpret embedded data (BP_EMBEDDED_TYPE_*)
 * comp                 compression function of payload
 * PSIZE                size of payload after compression, in bytes
 * LSIZE                logical size of payload, in bytes
 *                      note that 25 bits is enough to store the largest
 *                      "normal" BP's LSIZE (2^16 * 2^9) in bytes
 * log. birth           transaction group in which the block was logically born
 *
 * Note that LSIZE and PSIZE are stored in bytes, whereas for non-embedded
 * bp's they are stored in units of SPA_MINBLOCKSHIFT.
 * Generally, the generic BP_GET_*() macros can be used on embedded BP's.
 * The B, D, X, lvl, type, and comp fields are stored the same as with normal
 * BP's so the BP_SET_* macros can be used with them.  etype, PSIZE, LSIZE must
 * be set with the BPE_SET_* macros.  BP_SET_EMBEDDED() should be called before
 * other macros, as they assert that they are only used on BP's of the correct
 * "embedded-ness".
 */

#define BPE_GET_ETYPE(bp)       \
        (ASSERT(BP_IS_EMBEDDED(bp)), \
        BF64_GET((bp)->blk_prop, 40, 8))
#define BPE_SET_ETYPE(bp, t)    do { \
        ASSERT(BP_IS_EMBEDDED(bp)); \
        BF64_SET((bp)->blk_prop, 40, 8, t); \
_NOTE(CONSTCOND) } while (0)

#define BPE_GET_LSIZE(bp)       \
        (ASSERT(BP_IS_EMBEDDED(bp)), \
        BF64_GET_SB((bp)->blk_prop, 0, 25, 0, 1))
#define BPE_SET_LSIZE(bp, x)    do { \
        ASSERT(BP_IS_EMBEDDED(bp)); \
        BF64_SET_SB((bp)->blk_prop, 0, 25, 0, 1, x); \
_NOTE(CONSTCOND) } while (0)

#define BPE_GET_PSIZE(bp)       \
        (ASSERT(BP_IS_EMBEDDED(bp)), \
        BF64_GET_SB((bp)->blk_prop, 25, 7, 0, 1))
#define BPE_SET_PSIZE(bp, x)    do { \
        ASSERT(BP_IS_EMBEDDED(bp)); \
        BF64_SET_SB((bp)->blk_prop, 25, 7, 0, 1, x); \
_NOTE(CONSTCOND) } while (0)

typedef enum bp_embedded_type {
        BP_EMBEDDED_TYPE_DATA,
        BP_EMBEDDED_TYPE_RESERVED, /* Reserved for an unintegrated feature. */
        NUM_BP_EMBEDDED_TYPES = BP_EMBEDDED_TYPE_RESERVED
} bp_embedded_type_t;

#define BPE_NUM_WORDS 14
#define BPE_PAYLOAD_SIZE (BPE_NUM_WORDS * sizeof (uint64_t))
#define BPE_IS_PAYLOADWORD(bp, wp) \
        ((wp) != &(bp)->blk_prop && (wp) != &(bp)->blk_birth)

#define SPA_BLKPTRSHIFT 7               /* blkptr_t is 128 bytes        */
#define SPA_DVAS_PER_BP 3               /* Number of DVAs in a bp       */

typedef struct blkptr {
        dva_t           blk_dva[SPA_DVAS_PER_BP]; /* Data Virtual Addresses */
        uint64_t        blk_prop;       /* size, compression, type, etc     */
        uint64_t        blk_pad[2];     /* Extra space for the future       */
        uint64_t        blk_phys_birth; /* txg when block was allocated     */
        uint64_t        blk_birth;      /* transaction group at birth       */
        uint64_t        blk_fill;       /* fill count                       */
        zio_cksum_t     blk_cksum;      /* 256-bit checksum                 */
} blkptr_t;

/*
 * Macros to get and set fields in a bp or DVA.
 */
#define DVA_GET_ASIZE(dva)      \
        BF64_GET_SB((dva)->dva_word[0], 0, SPA_ASIZEBITS, SPA_MINBLOCKSHIFT, 0)
#define DVA_SET_ASIZE(dva, x)   \
        BF64_SET_SB((dva)->dva_word[0], 0, SPA_ASIZEBITS, \
        SPA_MINBLOCKSHIFT, 0, x)

#define DVA_GET_GRID(dva)       BF64_GET((dva)->dva_word[0], 24, 8)
#define DVA_SET_GRID(dva, x)    BF64_SET((dva)->dva_word[0], 24, 8, x)

#define DVA_GET_VDEV(dva)       BF64_GET((dva)->dva_word[0], 32, 32)
#define DVA_SET_VDEV(dva, x)    BF64_SET((dva)->dva_word[0], 32, 32, x)

#define DVA_GET_OFFSET(dva)     \
        BF64_GET_SB((dva)->dva_word[1], 0, 63, SPA_MINBLOCKSHIFT, 0)
#define DVA_SET_OFFSET(dva, x)  \
        BF64_SET_SB((dva)->dva_word[1], 0, 63, SPA_MINBLOCKSHIFT, 0, x)

#define DVA_GET_GANG(dva)       BF64_GET((dva)->dva_word[1], 63, 1)
#define DVA_SET_GANG(dva, x)    BF64_SET((dva)->dva_word[1], 63, 1, x)

#define BP_GET_LSIZE(bp)        \
        (BP_IS_EMBEDDED(bp) ?   \
        (BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA ? BPE_GET_LSIZE(bp) : 0): \
        BF64_GET_SB((bp)->blk_prop, 0, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1))
#define BP_SET_LSIZE(bp, x)     do { \
        ASSERT(!BP_IS_EMBEDDED(bp)); \
        BF64_SET_SB((bp)->blk_prop, \
            0, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1, x); \
_NOTE(CONSTCOND) } while (0)

#define BP_GET_PSIZE(bp)        \
        BF64_GET_SB((bp)->blk_prop, 16, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1)
#define BP_SET_PSIZE(bp, x)     \
        BF64_SET_SB((bp)->blk_prop, 16, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1, x)

#define BP_GET_COMPRESS(bp)     BF64_GET((bp)->blk_prop, 32, 7)
#define BP_SET_COMPRESS(bp, x)  BF64_SET((bp)->blk_prop, 32, 7, x)

#define BP_GET_CHECKSUM(bp)     BF64_GET((bp)->blk_prop, 40, 8)
#define BP_SET_CHECKSUM(bp, x)  BF64_SET((bp)->blk_prop, 40, 8, x)

#define BP_GET_TYPE(bp)         BF64_GET((bp)->blk_prop, 48, 8)
#define BP_SET_TYPE(bp, x)      BF64_SET((bp)->blk_prop, 48, 8, x)

#define BP_GET_LEVEL(bp)        BF64_GET((bp)->blk_prop, 56, 5)
#define BP_SET_LEVEL(bp, x)     BF64_SET((bp)->blk_prop, 56, 5, x)

#define BP_IS_EMBEDDED(bp)      BF64_GET((bp)->blk_prop, 39, 1)

#define BP_GET_DEDUP(bp)        BF64_GET((bp)->blk_prop, 62, 1)
#define BP_SET_DEDUP(bp, x)     BF64_SET((bp)->blk_prop, 62, 1, x)

#define BP_GET_BYTEORDER(bp)    BF64_GET((bp)->blk_prop, 63, 1)
#define BP_SET_BYTEORDER(bp, x) BF64_SET((bp)->blk_prop, 63, 1, x)

#define BP_PHYSICAL_BIRTH(bp)           \
        ((bp)->blk_phys_birth ? (bp)->blk_phys_birth : (bp)->blk_birth)

#define BP_GET_ASIZE(bp)        \
        (DVA_GET_ASIZE(&(bp)->blk_dva[0]) + DVA_GET_ASIZE(&(bp)->blk_dva[1]) + \
                DVA_GET_ASIZE(&(bp)->blk_dva[2]))

#define BP_GET_UCSIZE(bp) \
        ((BP_GET_LEVEL(bp) > 0 || dmu_ot[BP_GET_TYPE(bp)].ot_metadata) ? \
        BP_GET_PSIZE(bp) : BP_GET_LSIZE(bp));

#define BP_GET_NDVAS(bp)        \
        (!!DVA_GET_ASIZE(&(bp)->blk_dva[0]) + \
        !!DVA_GET_ASIZE(&(bp)->blk_dva[1]) + \
        !!DVA_GET_ASIZE(&(bp)->blk_dva[2]))

#define DVA_EQUAL(dva1, dva2)   \
        ((dva1)->dva_word[1] == (dva2)->dva_word[1] && \
        (dva1)->dva_word[0] == (dva2)->dva_word[0])

#define ZIO_CHECKSUM_EQUAL(zc1, zc2) \
        (0 == (((zc1).zc_word[0] - (zc2).zc_word[0]) | \
        ((zc1).zc_word[1] - (zc2).zc_word[1]) | \
        ((zc1).zc_word[2] - (zc2).zc_word[2]) | \
        ((zc1).zc_word[3] - (zc2).zc_word[3])))


#define DVA_IS_VALID(dva)       (DVA_GET_ASIZE(dva) != 0)

#define ZIO_SET_CHECKSUM(zcp, w0, w1, w2, w3)   \
{                                               \
        (zcp)->zc_word[0] = w0;                 \
        (zcp)->zc_word[1] = w1;                 \
        (zcp)->zc_word[2] = w2;                 \
        (zcp)->zc_word[3] = w3;                 \
}

#define BP_IDENTITY(bp)         (&(bp)->blk_dva[0])
#define BP_IS_GANG(bp)          DVA_GET_GANG(BP_IDENTITY(bp))
#define DVA_IS_EMPTY(dva)       ((dva)->dva_word[0] == 0ULL &&  \
        (dva)->dva_word[1] == 0ULL)
#define BP_IS_HOLE(bp)          DVA_IS_EMPTY(BP_IDENTITY(bp))
#define BP_IS_OLDER(bp, txg)    (!BP_IS_HOLE(bp) && (bp)->blk_birth < (txg))

#define BP_ZERO(bp)                             \
{                                               \
        (bp)->blk_dva[0].dva_word[0] = 0;       \
        (bp)->blk_dva[0].dva_word[1] = 0;       \
        (bp)->blk_dva[1].dva_word[0] = 0;       \
        (bp)->blk_dva[1].dva_word[1] = 0;       \
        (bp)->blk_dva[2].dva_word[0] = 0;       \
        (bp)->blk_dva[2].dva_word[1] = 0;       \
        (bp)->blk_prop = 0;                     \
        (bp)->blk_pad[0] = 0;                   \
        (bp)->blk_pad[1] = 0;                   \
        (bp)->blk_phys_birth = 0;               \
        (bp)->blk_birth = 0;                    \
        (bp)->blk_fill = 0;                     \
        ZIO_SET_CHECKSUM(&(bp)->blk_cksum, 0, 0, 0, 0); \
}

#if BYTE_ORDER == _BIG_ENDIAN
#define ZFS_HOST_BYTEORDER      (0ULL)
#else
#define ZFS_HOST_BYTEORDER      (1ULL)
#endif

#define BP_SHOULD_BYTESWAP(bp)  (BP_GET_BYTEORDER(bp) != ZFS_HOST_BYTEORDER)
#define BPE_NUM_WORDS 14
#define BPE_PAYLOAD_SIZE (BPE_NUM_WORDS * sizeof (uint64_t))
#define BPE_IS_PAYLOADWORD(bp, wp) \
        ((wp) != &(bp)->blk_prop && (wp) != &(bp)->blk_birth)

/*
 * Embedded checksum
 */
#define ZEC_MAGIC       0x210da7ab10c7a11ULL

typedef struct zio_eck {
        uint64_t        zec_magic;      /* for validation, endianness   */
        zio_cksum_t     zec_cksum;      /* 256-bit checksum             */
} zio_eck_t;

/*
 * Gang block headers are self-checksumming and contain an array
 * of block pointers.
 */
#define SPA_GANGBLOCKSIZE       SPA_MINBLOCKSIZE
#define SPA_GBH_NBLKPTRS        ((SPA_GANGBLOCKSIZE - \
        sizeof (zio_eck_t)) / sizeof (blkptr_t))
#define SPA_GBH_FILLER          ((SPA_GANGBLOCKSIZE - \
        sizeof (zio_eck_t) - \
        (SPA_GBH_NBLKPTRS * sizeof (blkptr_t))) /\
        sizeof (uint64_t))

typedef struct zio_gbh {
        blkptr_t                zg_blkptr[SPA_GBH_NBLKPTRS];
        uint64_t                zg_filler[SPA_GBH_FILLER];
        zio_eck_t               zg_tail;
} zio_gbh_phys_t;

#define VDEV_RAIDZ_MAXPARITY    3

#define VDEV_PAD_SIZE           (8 << 10)
/* 2 padding areas (vl_pad1 and vl_be) to skip */
#define VDEV_SKIP_SIZE          VDEV_PAD_SIZE * 2
#define VDEV_PHYS_SIZE          (112 << 10)
#define VDEV_UBERBLOCK_RING     (128 << 10)

/*
 * MMP blocks occupy the last MMP_BLOCKS_PER_LABEL slots in the uberblock
 * ring when MMP is enabled.
 */
#define MMP_BLOCKS_PER_LABEL    1

/* The largest uberblock we support is 8k. */
#define MAX_UBERBLOCK_SHIFT     (13)
#define VDEV_UBERBLOCK_SHIFT(vd)        \
        MIN(MAX((vd)->v_top->v_ashift, UBERBLOCK_SHIFT), MAX_UBERBLOCK_SHIFT)
#define VDEV_UBERBLOCK_COUNT(vd)        \
        (VDEV_UBERBLOCK_RING >> VDEV_UBERBLOCK_SHIFT(vd))
#define VDEV_UBERBLOCK_OFFSET(vd, n)    \
        offsetof(vdev_label_t, vl_uberblock[(n) << VDEV_UBERBLOCK_SHIFT(vd)])
#define VDEV_UBERBLOCK_SIZE(vd)         (1ULL << VDEV_UBERBLOCK_SHIFT(vd))

typedef struct vdev_phys {
        char            vp_nvlist[VDEV_PHYS_SIZE - sizeof (zio_eck_t)];
        zio_eck_t       vp_zbt;
} vdev_phys_t;

typedef enum vbe_vers {
        /* The bootenv file is stored as ascii text in the envblock */
        VB_RAW = 0,

        /*
         * The bootenv file is converted to an nvlist and then packed into the
         * envblock.
         */
        VB_NVLIST = 1
} vbe_vers_t;

typedef struct vdev_boot_envblock {
        uint64_t        vbe_version;
        char            vbe_bootenv[VDEV_PAD_SIZE - sizeof (uint64_t) -
                        sizeof (zio_eck_t)];
        zio_eck_t       vbe_zbt;
} vdev_boot_envblock_t;

CTASSERT(sizeof (vdev_boot_envblock_t) == VDEV_PAD_SIZE);

typedef struct vdev_label {
        char            vl_pad1[VDEV_PAD_SIZE];                 /*  8K  */
        vdev_boot_envblock_t    vl_be;                          /*  8K  */
        vdev_phys_t     vl_vdev_phys;                           /* 112K */
        char            vl_uberblock[VDEV_UBERBLOCK_RING];      /* 128K */
} vdev_label_t;                                                 /* 256K total */

/*
 * vdev_dirty() flags
 */
#define VDD_METASLAB    0x01
#define VDD_DTL         0x02

/*
 * Size and offset of embedded boot loader region on each label.
 * The total size of the first two labels plus the boot area is 4MB.
 */
#define VDEV_BOOT_OFFSET        (2 * sizeof (vdev_label_t))
#define VDEV_BOOT_SIZE          (7ULL << 19)                    /* 3.5M */

/*
 * Size of label regions at the start and end of each leaf device.
 */
#define VDEV_LABEL_START_SIZE   (2 * sizeof (vdev_label_t) + VDEV_BOOT_SIZE)
#define VDEV_LABEL_END_SIZE     (2 * sizeof (vdev_label_t))
#define VDEV_LABELS             4

enum zio_checksum {
        ZIO_CHECKSUM_INHERIT = 0,
        ZIO_CHECKSUM_ON,
        ZIO_CHECKSUM_OFF,
        ZIO_CHECKSUM_LABEL,
        ZIO_CHECKSUM_GANG_HEADER,
        ZIO_CHECKSUM_ZILOG,
        ZIO_CHECKSUM_FLETCHER_2,
        ZIO_CHECKSUM_FLETCHER_4,
        ZIO_CHECKSUM_SHA256,
        ZIO_CHECKSUM_ZILOG2,
        ZIO_CHECKSUM_NOPARITY,
        ZIO_CHECKSUM_SHA512,
        ZIO_CHECKSUM_SKEIN,
        ZIO_CHECKSUM_EDONR,
        ZIO_CHECKSUM_FUNCTIONS
};

#define ZIO_CHECKSUM_ON_VALUE   ZIO_CHECKSUM_FLETCHER_4
#define ZIO_CHECKSUM_DEFAULT    ZIO_CHECKSUM_ON

enum zio_compress {
        ZIO_COMPRESS_INHERIT = 0,
        ZIO_COMPRESS_ON,
        ZIO_COMPRESS_OFF,
        ZIO_COMPRESS_LZJB,
        ZIO_COMPRESS_EMPTY,
        ZIO_COMPRESS_GZIP_1,
        ZIO_COMPRESS_GZIP_2,
        ZIO_COMPRESS_GZIP_3,
        ZIO_COMPRESS_GZIP_4,
        ZIO_COMPRESS_GZIP_5,
        ZIO_COMPRESS_GZIP_6,
        ZIO_COMPRESS_GZIP_7,
        ZIO_COMPRESS_GZIP_8,
        ZIO_COMPRESS_GZIP_9,
        ZIO_COMPRESS_ZLE,
        ZIO_COMPRESS_LZ4,
        ZIO_COMPRESS_FUNCTIONS
};

#define ZIO_COMPRESS_ON_VALUE   ZIO_COMPRESS_LZJB
#define ZIO_COMPRESS_DEFAULT    ZIO_COMPRESS_OFF

/* nvlist pack encoding */
#define NV_ENCODE_NATIVE        0
#define NV_ENCODE_XDR           1

typedef enum {
        DATA_TYPE_UNKNOWN = 0,
        DATA_TYPE_BOOLEAN,
        DATA_TYPE_BYTE,
        DATA_TYPE_INT16,
        DATA_TYPE_UINT16,
        DATA_TYPE_INT32,
        DATA_TYPE_UINT32,
        DATA_TYPE_INT64,
        DATA_TYPE_UINT64,
        DATA_TYPE_STRING,
        DATA_TYPE_BYTE_ARRAY,
        DATA_TYPE_INT16_ARRAY,
        DATA_TYPE_UINT16_ARRAY,
        DATA_TYPE_INT32_ARRAY,
        DATA_TYPE_UINT32_ARRAY,
        DATA_TYPE_INT64_ARRAY,
        DATA_TYPE_UINT64_ARRAY,
        DATA_TYPE_STRING_ARRAY,
        DATA_TYPE_HRTIME,
        DATA_TYPE_NVLIST,
        DATA_TYPE_NVLIST_ARRAY,
        DATA_TYPE_BOOLEAN_VALUE,
        DATA_TYPE_INT8,
        DATA_TYPE_UINT8,
        DATA_TYPE_BOOLEAN_ARRAY,
        DATA_TYPE_INT8_ARRAY,
        DATA_TYPE_UINT8_ARRAY
} data_type_t;

/*
 * On-disk version number.
 */
#define SPA_VERSION_1                   1ULL
#define SPA_VERSION_2                   2ULL
#define SPA_VERSION_3                   3ULL
#define SPA_VERSION_4                   4ULL
#define SPA_VERSION_5                   5ULL
#define SPA_VERSION_6                   6ULL
#define SPA_VERSION_7                   7ULL
#define SPA_VERSION_8                   8ULL
#define SPA_VERSION_9                   9ULL
#define SPA_VERSION_10                  10ULL
#define SPA_VERSION_11                  11ULL
#define SPA_VERSION_12                  12ULL
#define SPA_VERSION_13                  13ULL
#define SPA_VERSION_14                  14ULL
#define SPA_VERSION_15                  15ULL
#define SPA_VERSION_16                  16ULL
#define SPA_VERSION_17                  17ULL
#define SPA_VERSION_18                  18ULL
#define SPA_VERSION_19                  19ULL
#define SPA_VERSION_20                  20ULL
#define SPA_VERSION_21                  21ULL
#define SPA_VERSION_22                  22ULL
#define SPA_VERSION_23                  23ULL
#define SPA_VERSION_24                  24ULL
#define SPA_VERSION_25                  25ULL
#define SPA_VERSION_26                  26ULL
#define SPA_VERSION_27                  27ULL
#define SPA_VERSION_28                  28ULL
#define SPA_VERSION_5000                5000ULL

/*
 * When bumping up SPA_VERSION, make sure GRUB ZFS understands the on-disk
 * format change. Go to usr/src/grub/grub-0.97/stage2/{zfs-include/, fsys_zfs*},
 * and do the appropriate changes.  Also bump the version number in
 * usr/src/grub/capability.
 */
#define SPA_VERSION                     SPA_VERSION_5000
#define SPA_VERSION_STRING              "5000"

/*
 * Symbolic names for the changes that caused a SPA_VERSION switch.
 * Used in the code when checking for presence or absence of a feature.
 * Feel free to define multiple symbolic names for each version if there
 * were multiple changes to on-disk structures during that version.
 *
 * NOTE: When checking the current SPA_VERSION in your code, be sure
 *       to use spa_version() since it reports the version of the
 *       last synced uberblock.  Checking the in-flight version can
 *       be dangerous in some cases.
 */
#define SPA_VERSION_INITIAL             SPA_VERSION_1
#define SPA_VERSION_DITTO_BLOCKS        SPA_VERSION_2
#define SPA_VERSION_SPARES              SPA_VERSION_3
#define SPA_VERSION_RAID6               SPA_VERSION_3
#define SPA_VERSION_BPLIST_ACCOUNT      SPA_VERSION_3
#define SPA_VERSION_RAIDZ_DEFLATE       SPA_VERSION_3
#define SPA_VERSION_DNODE_BYTES         SPA_VERSION_3
#define SPA_VERSION_ZPOOL_HISTORY       SPA_VERSION_4
#define SPA_VERSION_GZIP_COMPRESSION    SPA_VERSION_5
#define SPA_VERSION_BOOTFS              SPA_VERSION_6
#define SPA_VERSION_SLOGS               SPA_VERSION_7
#define SPA_VERSION_DELEGATED_PERMS     SPA_VERSION_8
#define SPA_VERSION_FUID                SPA_VERSION_9
#define SPA_VERSION_REFRESERVATION      SPA_VERSION_9
#define SPA_VERSION_REFQUOTA            SPA_VERSION_9
#define SPA_VERSION_UNIQUE_ACCURATE     SPA_VERSION_9
#define SPA_VERSION_L2CACHE             SPA_VERSION_10
#define SPA_VERSION_NEXT_CLONES         SPA_VERSION_11
#define SPA_VERSION_ORIGIN              SPA_VERSION_11
#define SPA_VERSION_DSL_SCRUB           SPA_VERSION_11
#define SPA_VERSION_SNAP_PROPS          SPA_VERSION_12
#define SPA_VERSION_USED_BREAKDOWN      SPA_VERSION_13
#define SPA_VERSION_PASSTHROUGH_X       SPA_VERSION_14
#define SPA_VERSION_USERSPACE           SPA_VERSION_15
#define SPA_VERSION_STMF_PROP           SPA_VERSION_16
#define SPA_VERSION_RAIDZ3              SPA_VERSION_17
#define SPA_VERSION_USERREFS            SPA_VERSION_18
#define SPA_VERSION_HOLES               SPA_VERSION_19
#define SPA_VERSION_ZLE_COMPRESSION     SPA_VERSION_20
#define SPA_VERSION_DEDUP               SPA_VERSION_21
#define SPA_VERSION_RECVD_PROPS         SPA_VERSION_22
#define SPA_VERSION_SLIM_ZIL            SPA_VERSION_23
#define SPA_VERSION_SA                  SPA_VERSION_24
#define SPA_VERSION_SCAN                SPA_VERSION_25
#define SPA_VERSION_DIR_CLONES          SPA_VERSION_26
#define SPA_VERSION_DEADLISTS           SPA_VERSION_26
#define SPA_VERSION_FAST_SNAP           SPA_VERSION_27
#define SPA_VERSION_MULTI_REPLACE       SPA_VERSION_28
#define SPA_VERSION_BEFORE_FEATURES     SPA_VERSION_28
#define SPA_VERSION_FEATURES            SPA_VERSION_5000

#define SPA_VERSION_IS_SUPPORTED(v) \
        (((v) >= SPA_VERSION_INITIAL && (v) <= SPA_VERSION_BEFORE_FEATURES) || \
        ((v) >= SPA_VERSION_FEATURES && (v) <= SPA_VERSION))

/*
 * The following are configuration names used in the nvlist describing a pool's
 * configuration.
 */
#define ZPOOL_CONFIG_VERSION            "version"
#define ZPOOL_CONFIG_POOL_NAME          "name"
#define ZPOOL_CONFIG_POOL_STATE         "state"
#define ZPOOL_CONFIG_POOL_TXG           "txg"
#define ZPOOL_CONFIG_POOL_GUID          "pool_guid"
#define ZPOOL_CONFIG_CREATE_TXG         "create_txg"
#define ZPOOL_CONFIG_TOP_GUID           "top_guid"
#define ZPOOL_CONFIG_VDEV_TREE          "vdev_tree"
#define ZPOOL_CONFIG_TYPE               "type"
#define ZPOOL_CONFIG_CHILDREN           "children"
#define ZPOOL_CONFIG_ID                 "id"
#define ZPOOL_CONFIG_GUID               "guid"
#define ZPOOL_CONFIG_INDIRECT_OBJECT    "com.delphix:indirect_object"
#define ZPOOL_CONFIG_INDIRECT_BIRTHS    "com.delphix:indirect_births"
#define ZPOOL_CONFIG_PREV_INDIRECT_VDEV "com.delphix:prev_indirect_vdev"
#define ZPOOL_CONFIG_PATH               "path"
#define ZPOOL_CONFIG_DEVID              "devid"
#define ZPOOL_CONFIG_METASLAB_ARRAY     "metaslab_array"
#define ZPOOL_CONFIG_METASLAB_SHIFT     "metaslab_shift"
#define ZPOOL_CONFIG_ASHIFT             "ashift"
#define ZPOOL_CONFIG_ASIZE              "asize"
#define ZPOOL_CONFIG_DTL                "DTL"
#define ZPOOL_CONFIG_STATS              "stats"
#define ZPOOL_CONFIG_WHOLE_DISK         "whole_disk"
#define ZPOOL_CONFIG_ERRCOUNT           "error_count"
#define ZPOOL_CONFIG_NOT_PRESENT        "not_present"
#define ZPOOL_CONFIG_SPARES             "spares"
#define ZPOOL_CONFIG_IS_SPARE           "is_spare"
#define ZPOOL_CONFIG_NPARITY            "nparity"
#define ZPOOL_CONFIG_HOSTID             "hostid"
#define ZPOOL_CONFIG_HOSTNAME           "hostname"
#define ZPOOL_CONFIG_IS_LOG             "is_log"
#define ZPOOL_CONFIG_TIMESTAMP          "timestamp" /* not stored on disk */
#define ZPOOL_CONFIG_FEATURES_FOR_READ  "features_for_read"
#define ZPOOL_CONFIG_VDEV_CHILDREN      "vdev_children"

/*
 * The persistent vdev state is stored as separate values rather than a single
 * 'vdev_state' entry.  This is because a device can be in multiple states, such
 * as offline and degraded.
 */
#define ZPOOL_CONFIG_OFFLINE            "offline"
#define ZPOOL_CONFIG_FAULTED            "faulted"
#define ZPOOL_CONFIG_DEGRADED           "degraded"
#define ZPOOL_CONFIG_REMOVED            "removed"
#define ZPOOL_CONFIG_FRU                "fru"
#define ZPOOL_CONFIG_AUX_STATE          "aux_state"

#define VDEV_TYPE_ROOT                  "root"
#define VDEV_TYPE_MIRROR                "mirror"
#define VDEV_TYPE_REPLACING             "replacing"
#define VDEV_TYPE_RAIDZ                 "raidz"
#define VDEV_TYPE_DISK                  "disk"
#define VDEV_TYPE_FILE                  "file"
#define VDEV_TYPE_MISSING               "missing"
#define VDEV_TYPE_HOLE                  "hole"
#define VDEV_TYPE_SPARE                 "spare"
#define VDEV_TYPE_LOG                   "log"
#define VDEV_TYPE_L2CACHE               "l2cache"
#define VDEV_TYPE_INDIRECT              "indirect"

/*
 * This is needed in userland to report the minimum necessary device size.
 */
#define SPA_MINDEVSIZE          (64ULL << 20)

/*
 * The location of the pool configuration repository, shared between kernel and
 * userland.
 */
#define ZPOOL_CACHE             "/boot/zfs/zpool.cache"

/*
 * vdev states are ordered from least to most healthy.
 * A vdev that's CANT_OPEN or below is considered unusable.
 */
typedef enum vdev_state {
        VDEV_STATE_UNKNOWN = 0, /* Uninitialized vdev                   */
        VDEV_STATE_CLOSED,      /* Not currently open                   */
        VDEV_STATE_OFFLINE,     /* Not allowed to open                  */
        VDEV_STATE_REMOVED,     /* Explicitly removed from system       */
        VDEV_STATE_CANT_OPEN,   /* Tried to open, but failed            */
        VDEV_STATE_FAULTED,     /* External request to fault device     */
        VDEV_STATE_DEGRADED,    /* Replicated vdev with unhealthy kids  */
        VDEV_STATE_HEALTHY      /* Presumed good                        */
} vdev_state_t;

/*
 * vdev aux states.  When a vdev is in the CANT_OPEN state, the aux field
 * of the vdev stats structure uses these constants to distinguish why.
 */
typedef enum vdev_aux {
        VDEV_AUX_NONE,          /* no error                             */
        VDEV_AUX_OPEN_FAILED,   /* ldi_open_*() or vn_open() failed     */
        VDEV_AUX_CORRUPT_DATA,  /* bad label or disk contents           */
        VDEV_AUX_NO_REPLICAS,   /* insufficient number of replicas      */
        VDEV_AUX_BAD_GUID_SUM,  /* vdev guid sum doesn't match          */
        VDEV_AUX_TOO_SMALL,     /* vdev size is too small               */
        VDEV_AUX_BAD_LABEL,     /* the label is OK but invalid          */
        VDEV_AUX_VERSION_NEWER, /* on-disk version is too new           */
        VDEV_AUX_VERSION_OLDER, /* on-disk version is too old           */
        VDEV_AUX_SPARED         /* hot spare used in another pool       */
} vdev_aux_t;

/*
 * pool state.  The following states are written to disk as part of the normal
 * SPA lifecycle: ACTIVE, EXPORTED, DESTROYED, SPARE.  The remaining states are
 * software abstractions used at various levels to communicate pool state.
 */
typedef enum pool_state {
        POOL_STATE_ACTIVE = 0,          /* In active use                */
        POOL_STATE_EXPORTED,            /* Explicitly exported          */
        POOL_STATE_DESTROYED,           /* Explicitly destroyed         */
        POOL_STATE_SPARE,               /* Reserved for hot spare use   */
        POOL_STATE_UNINITIALIZED,       /* Internal spa_t state         */
        POOL_STATE_UNAVAIL,             /* Internal libzfs state        */
        POOL_STATE_POTENTIALLY_ACTIVE   /* Internal libzfs state        */
} pool_state_t;

/*
 * The uberblock version is incremented whenever an incompatible on-disk
 * format change is made to the SPA, DMU, or ZAP.
 *
 * Note: the first two fields should never be moved.  When a storage pool
 * is opened, the uberblock must be read off the disk before the version
 * can be checked.  If the ub_version field is moved, we may not detect
 * version mismatch.  If the ub_magic field is moved, applications that
 * expect the magic number in the first word won't work.
 */
#define UBERBLOCK_MAGIC         0x00bab10c              /* oo-ba-bloc!  */
#define UBERBLOCK_SHIFT         10                      /* up to 1K     */

#define MMP_MAGIC               0xa11cea11              /* all-see-all  */

#define MMP_INTERVAL_VALID_BIT  0x01
#define MMP_SEQ_VALID_BIT       0x02
#define MMP_FAIL_INT_VALID_BIT  0x04

#define MMP_VALID(ubp)          (ubp->ub_magic == UBERBLOCK_MAGIC && \
                                    ubp->ub_mmp_magic == MMP_MAGIC)
#define MMP_INTERVAL_VALID(ubp) (MMP_VALID(ubp) && (ubp->ub_mmp_config & \
                                    MMP_INTERVAL_VALID_BIT))
#define MMP_SEQ_VALID(ubp)      (MMP_VALID(ubp) && (ubp->ub_mmp_config & \
                                    MMP_SEQ_VALID_BIT))
#define MMP_FAIL_INT_VALID(ubp) (MMP_VALID(ubp) && (ubp->ub_mmp_config & \
                                    MMP_FAIL_INT_VALID_BIT))

#define MMP_INTERVAL(ubp)       ((ubp->ub_mmp_config & 0x00000000FFFFFF00) \
                                    >> 8)
#define MMP_SEQ(ubp)            ((ubp->ub_mmp_config & 0x0000FFFF00000000) \
                                    >> 32)
#define MMP_FAIL_INT(ubp)       ((ubp->ub_mmp_config & 0xFFFF000000000000) \
                                    >> 48)

typedef struct uberblock {
        uint64_t        ub_magic;       /* UBERBLOCK_MAGIC              */
        uint64_t        ub_version;     /* SPA_VERSION                  */
        uint64_t        ub_txg;         /* txg of last sync             */
        uint64_t        ub_guid_sum;    /* sum of all vdev guids        */
        uint64_t        ub_timestamp;   /* UTC time of last sync        */
        blkptr_t        ub_rootbp;      /* MOS objset_phys_t            */
        /* highest SPA_VERSION supported by software that wrote this txg */
        uint64_t        ub_software_version;
        /* Maybe missing in uberblocks we read, but always written */
        uint64_t        ub_mmp_magic;
        /*
         * If ub_mmp_delay == 0 and ub_mmp_magic is valid, MMP is off.
         * Otherwise, nanosec since last MMP write.
         */
        uint64_t        ub_mmp_delay;

        /*
         * The ub_mmp_config contains the multihost write interval, multihost
         * fail intervals, sequence number for sub-second granularity, and
         * valid bit mask.  This layout is as follows:
         *
         *   64      56      48      40      32      24      16      8       0
         *   +-------+-------+-------+-------+-------+-------+-------+-------+
         * 0 | Fail Intervals|      Seq      |   Write Interval (ms) | VALID |
         *   +-------+-------+-------+-------+-------+-------+-------+-------+
         *
         * This allows a write_interval of (2^24/1000)s, over 4.5 hours
         *
         * VALID Bits:
         * - 0x01 - Write Interval (ms)
         * - 0x02 - Sequence number exists
         * - 0x04 - Fail Intervals
         * - 0xf8 - Reserved
         */
        uint64_t        ub_mmp_config;

        /*
         * ub_checkpoint_txg indicates two things about the current uberblock:
         *
         * 1] If it is not zero then this uberblock is a checkpoint. If it is
         *    zero, then this uberblock is not a checkpoint.
         *
         * 2] On checkpointed uberblocks, the value of ub_checkpoint_txg is
         *    the ub_txg that the uberblock had at the time we moved it to
         *    the MOS config.
         *
         * The field is set when we checkpoint the uberblock and continues to
         * hold that value even after we've rewound (unlike the ub_txg that
         * is reset to a higher value).
         *
         * Besides checks used to determine whether we are reopening the
         * pool from a checkpointed uberblock [see spa_ld_select_uberblock()],
         * the value of the field is used to determine which ZIL blocks have
         * been allocated according to the ms_sm when we are rewinding to a
         * checkpoint. Specifically, if blk_birth > ub_checkpoint_txg, then
         * the ZIL block is not allocated [see uses of spa_min_claim_txg()].
         */
        uint64_t        ub_checkpoint_txg;
} uberblock_t;

/*
 * Flags.
 */
#define DNODE_MUST_BE_ALLOCATED 1
#define DNODE_MUST_BE_FREE      2

/*
 * Fixed constants.
 */
#define DNODE_SHIFT             9       /* 512 bytes */
#define DN_MIN_INDBLKSHIFT      12      /* 4k */
#define DN_MAX_INDBLKSHIFT      17      /* 128k */
#define DNODE_BLOCK_SHIFT       14      /* 16k */
#define DNODE_CORE_SIZE         64      /* 64 bytes for dnode sans blkptrs */
#define DN_MAX_OBJECT_SHIFT     48      /* 256 trillion (zfs_fid_t limit) */
#define DN_MAX_OFFSET_SHIFT     64      /* 2^64 bytes in a dnode */

/*
 * Derived constants.
 */
#define DNODE_MIN_SIZE          (1 << DNODE_SHIFT)
#define DNODE_MAX_SIZE          (1 << DNODE_BLOCK_SHIFT)
#define DNODE_BLOCK_SIZE        (1 << DNODE_BLOCK_SHIFT)
#define DNODE_MIN_SLOTS         (DNODE_MIN_SIZE >> DNODE_SHIFT)
#define DNODE_MAX_SLOTS         (DNODE_MAX_SIZE >> DNODE_SHIFT)
#define DN_BONUS_SIZE(dnsize)   ((dnsize) - DNODE_CORE_SIZE - \
        (1 << SPA_BLKPTRSHIFT))
#define DN_SLOTS_TO_BONUSLEN(slots)     DN_BONUS_SIZE((slots) << DNODE_SHIFT)
#define DN_OLD_MAX_BONUSLEN             (DN_BONUS_SIZE(DNODE_MIN_SIZE))
#define DN_MAX_NBLKPTR          ((DNODE_MIN_SIZE - DNODE_CORE_SIZE) >> \
        SPA_BLKPTRSHIFT)
#define DN_MAX_OBJECT           (1ULL << DN_MAX_OBJECT_SHIFT)
#define DN_ZERO_BONUSLEN        (DN_BONUS_SIZE(DNODE_MAX_SIZE) + 1)

#define DNODES_PER_BLOCK_SHIFT  (DNODE_BLOCK_SHIFT - DNODE_SHIFT)
#define DNODES_PER_BLOCK        (1ULL << DNODES_PER_BLOCK_SHIFT)
#define DNODES_PER_LEVEL_SHIFT  (DN_MAX_INDBLKSHIFT - SPA_BLKPTRSHIFT)

/* The +2 here is a cheesy way to round up */
#define DN_MAX_LEVELS   (2 + ((DN_MAX_OFFSET_SHIFT - SPA_MINBLOCKSHIFT) / \
        (DN_MIN_INDBLKSHIFT - SPA_BLKPTRSHIFT)))

#define DN_BONUS(dnp)   ((void*)((dnp)->dn_bonus + \
        (((dnp)->dn_nblkptr - 1) * sizeof (blkptr_t))))

#define DN_USED_BYTES(dnp) (((dnp)->dn_flags & DNODE_FLAG_USED_BYTES) ? \
        (dnp)->dn_used : (dnp)->dn_used << SPA_MINBLOCKSHIFT)

#define EPB(blkshift, typeshift)        (1 << (blkshift - typeshift))

/* Is dn_used in bytes?  if not, it's in multiples of SPA_MINBLOCKSIZE */
#define DNODE_FLAG_USED_BYTES           (1<<0)
#define DNODE_FLAG_USERUSED_ACCOUNTED   (1<<1)

/* Does dnode have a SA spill blkptr in bonus? */
#define DNODE_FLAG_SPILL_BLKPTR (1<<2)

typedef struct dnode_phys {
        uint8_t dn_type;                /* dmu_object_type_t */
        uint8_t dn_indblkshift;         /* ln2(indirect block size) */
        uint8_t dn_nlevels;             /* 1=dn_blkptr->data blocks */
        uint8_t dn_nblkptr;             /* length of dn_blkptr */
        uint8_t dn_bonustype;           /* type of data in bonus buffer */
        uint8_t dn_checksum;            /* ZIO_CHECKSUM type */
        uint8_t dn_compress;            /* ZIO_COMPRESS type */
        uint8_t dn_flags;               /* DNODE_FLAG_* */
        uint16_t dn_datablkszsec;       /* data block size in 512b sectors */
        uint16_t dn_bonuslen;           /* length of dn_bonus */
        uint8_t dn_extra_slots;         /* # of subsequent slots consumed */
        uint8_t dn_pad2[3];

        /* accounting is protected by dn_dirty_mtx */
        uint64_t dn_maxblkid;           /* largest allocated block ID */
        uint64_t dn_used;               /* bytes (or sectors) of disk space */

        uint64_t dn_pad3[4];

        /*
         * The tail region is 448 bytes for a 512 byte dnode, and
         * correspondingly larger for larger dnode sizes. The spill
         * block pointer, when present, is always at the end of the tail
         * region. There are three ways this space may be used, using
         * a 512 byte dnode for this diagram:
         *
         * 0       64      128     192     256     320     384     448 (offset)
         * +---------------+---------------+---------------+-------+
         * | dn_blkptr[0]  | dn_blkptr[1]  | dn_blkptr[2]  | /     |
         * +---------------+---------------+---------------+-------+
         * | dn_blkptr[0]  | dn_bonus[0..319]                      |
         * +---------------+-----------------------+---------------+
         * | dn_blkptr[0]  | dn_bonus[0..191]      | dn_spill      |
         * +---------------+-----------------------+---------------+
         */
        union {
                blkptr_t dn_blkptr[1+DN_OLD_MAX_BONUSLEN/sizeof (blkptr_t)];
                struct {
                        blkptr_t __dn_ignore1;
                        uint8_t dn_bonus[DN_OLD_MAX_BONUSLEN];
                };
                struct {
                        blkptr_t __dn_ignore2;
                        uint8_t __dn_ignore3[DN_OLD_MAX_BONUSLEN -
                            sizeof (blkptr_t)];
                        blkptr_t dn_spill;
                };
        };
} dnode_phys_t;

#define DN_SPILL_BLKPTR(dnp)    (blkptr_t *)((char *)(dnp) + \
        (((dnp)->dn_extra_slots + 1) << DNODE_SHIFT) - (1 << SPA_BLKPTRSHIFT))

typedef enum dmu_object_byteswap {
        DMU_BSWAP_UINT8,
        DMU_BSWAP_UINT16,
        DMU_BSWAP_UINT32,
        DMU_BSWAP_UINT64,
        DMU_BSWAP_ZAP,
        DMU_BSWAP_DNODE,
        DMU_BSWAP_OBJSET,
        DMU_BSWAP_ZNODE,
        DMU_BSWAP_OLDACL,
        DMU_BSWAP_ACL,
        /*
         * Allocating a new byteswap type number makes the on-disk format
         * incompatible with any other format that uses the same number.
         *
         * Data can usually be structured to work with one of the
         * DMU_BSWAP_UINT* or DMU_BSWAP_ZAP types.
         */
        DMU_BSWAP_NUMFUNCS
} dmu_object_byteswap_t;

#define DMU_OT_NEWTYPE 0x80
#define DMU_OT_METADATA 0x40
#define DMU_OT_BYTESWAP_MASK 0x3f

/*
 * Defines a uint8_t object type. Object types specify if the data
 * in the object is metadata (boolean) and how to byteswap the data
 * (dmu_object_byteswap_t).
 */
#define DMU_OT(byteswap, metadata) \
        (DMU_OT_NEWTYPE | \
        ((metadata) ? DMU_OT_METADATA : 0) | \
        ((byteswap) & DMU_OT_BYTESWAP_MASK))

typedef enum dmu_object_type {
        DMU_OT_NONE,
        /* general: */
        DMU_OT_OBJECT_DIRECTORY,        /* ZAP */
        DMU_OT_OBJECT_ARRAY,            /* UINT64 */
        DMU_OT_PACKED_NVLIST,           /* UINT8 (XDR by nvlist_pack/unpack) */
        DMU_OT_PACKED_NVLIST_SIZE,      /* UINT64 */
        DMU_OT_BPLIST,                  /* UINT64 */
        DMU_OT_BPLIST_HDR,              /* UINT64 */
        /* spa: */
        DMU_OT_SPACE_MAP_HEADER,        /* UINT64 */
        DMU_OT_SPACE_MAP,               /* UINT64 */
        /* zil: */
        DMU_OT_INTENT_LOG,              /* UINT64 */
        /* dmu: */
        DMU_OT_DNODE,                   /* DNODE */
        DMU_OT_OBJSET,                  /* OBJSET */
        /* dsl: */
        DMU_OT_DSL_DIR,                 /* UINT64 */
        DMU_OT_DSL_DIR_CHILD_MAP,       /* ZAP */
        DMU_OT_DSL_DS_SNAP_MAP,         /* ZAP */
        DMU_OT_DSL_PROPS,               /* ZAP */
        DMU_OT_DSL_DATASET,             /* UINT64 */
        /* zpl: */
        DMU_OT_ZNODE,                   /* ZNODE */
        DMU_OT_OLDACL,                  /* Old ACL */
        DMU_OT_PLAIN_FILE_CONTENTS,     /* UINT8 */
        DMU_OT_DIRECTORY_CONTENTS,      /* ZAP */
        DMU_OT_MASTER_NODE,             /* ZAP */
        DMU_OT_UNLINKED_SET,            /* ZAP */
        /* zvol: */
        DMU_OT_ZVOL,                    /* UINT8 */
        DMU_OT_ZVOL_PROP,               /* ZAP */
        /* other; for testing only! */
        DMU_OT_PLAIN_OTHER,             /* UINT8 */
        DMU_OT_UINT64_OTHER,            /* UINT64 */
        DMU_OT_ZAP_OTHER,               /* ZAP */
        /* new object types: */
        DMU_OT_ERROR_LOG,               /* ZAP */
        DMU_OT_SPA_HISTORY,             /* UINT8 */
        DMU_OT_SPA_HISTORY_OFFSETS,     /* spa_his_phys_t */
        DMU_OT_POOL_PROPS,              /* ZAP */
        DMU_OT_DSL_PERMS,               /* ZAP */
        DMU_OT_ACL,                     /* ACL */
        DMU_OT_SYSACL,                  /* SYSACL */
        DMU_OT_FUID,                    /* FUID table (Packed NVLIST UINT8) */
        DMU_OT_FUID_SIZE,               /* FUID table size UINT64 */
        DMU_OT_NEXT_CLONES,             /* ZAP */
        DMU_OT_SCAN_QUEUE,              /* ZAP */
        DMU_OT_USERGROUP_USED,          /* ZAP */
        DMU_OT_USERGROUP_QUOTA,         /* ZAP */
        DMU_OT_USERREFS,                /* ZAP */
        DMU_OT_DDT_ZAP,                 /* ZAP */
        DMU_OT_DDT_STATS,               /* ZAP */
        DMU_OT_SA,                      /* System attr */
        DMU_OT_SA_MASTER_NODE,          /* ZAP */
        DMU_OT_SA_ATTR_REGISTRATION,    /* ZAP */
        DMU_OT_SA_ATTR_LAYOUTS,         /* ZAP */
        DMU_OT_SCAN_XLATE,              /* ZAP */
        DMU_OT_DEDUP,                   /* fake dedup BP from ddt_bp_create() */
        DMU_OT_NUMTYPES,

        /*
         * Names for valid types declared with DMU_OT().
         */
        DMU_OTN_UINT8_DATA = DMU_OT(DMU_BSWAP_UINT8, B_FALSE),
        DMU_OTN_UINT8_METADATA = DMU_OT(DMU_BSWAP_UINT8, B_TRUE),
        DMU_OTN_UINT16_DATA = DMU_OT(DMU_BSWAP_UINT16, B_FALSE),
        DMU_OTN_UINT16_METADATA = DMU_OT(DMU_BSWAP_UINT16, B_TRUE),
        DMU_OTN_UINT32_DATA = DMU_OT(DMU_BSWAP_UINT32, B_FALSE),
        DMU_OTN_UINT32_METADATA = DMU_OT(DMU_BSWAP_UINT32, B_TRUE),
        DMU_OTN_UINT64_DATA = DMU_OT(DMU_BSWAP_UINT64, B_FALSE),
        DMU_OTN_UINT64_METADATA = DMU_OT(DMU_BSWAP_UINT64, B_TRUE),
        DMU_OTN_ZAP_DATA = DMU_OT(DMU_BSWAP_ZAP, B_FALSE),
        DMU_OTN_ZAP_METADATA = DMU_OT(DMU_BSWAP_ZAP, B_TRUE)
} dmu_object_type_t;

typedef enum dmu_objset_type {
        DMU_OST_NONE,
        DMU_OST_META,
        DMU_OST_ZFS,
        DMU_OST_ZVOL,
        DMU_OST_OTHER,                  /* For testing only! */
        DMU_OST_ANY,                    /* Be careful! */
        DMU_OST_NUMTYPES
} dmu_objset_type_t;

#define ZAP_MAXVALUELEN (1024 * 8)

/*
 * header for all bonus and spill buffers.
 * The header has a fixed portion with a variable number
 * of "lengths" depending on the number of variable sized
 * attribues which are determined by the "layout number"
 */

#define SA_MAGIC        0x2F505A  /* ZFS SA */
typedef struct sa_hdr_phys {
        uint32_t sa_magic;
        uint16_t sa_layout_info;  /* Encoded with hdrsize and layout number */
        uint16_t sa_lengths[1]; /* optional sizes for variable length attrs */
        /* ... Data follows the lengths.  */
} sa_hdr_phys_t;

/*
 * sa_hdr_phys -> sa_layout_info
 *
 * 16      10       0
 * +--------+-------+
 * | hdrsz  |layout |
 * +--------+-------+
 *
 * Bits 0-10 are the layout number
 * Bits 11-16 are the size of the header.
 * The hdrsize is the number * 8
 *
 * For example.
 * hdrsz of 1 ==> 8 byte header
 *          2 ==> 16 byte header
 *
 */

#define SA_HDR_LAYOUT_NUM(hdr) BF32_GET(hdr->sa_layout_info, 0, 10)
#define SA_HDR_SIZE(hdr) BF32_GET_SB(hdr->sa_layout_info, 10, 16, 3, 0)
#define SA_HDR_LAYOUT_INFO_ENCODE(x, num, size) \
{ \
        BF32_SET_SB(x, 10, 6, 3, 0, size); \
        BF32_SET(x, 0, 10, num); \
}

#define SA_MODE_OFFSET          0
#define SA_SIZE_OFFSET          8
#define SA_GEN_OFFSET           16
#define SA_UID_OFFSET           24
#define SA_GID_OFFSET           32
#define SA_PARENT_OFFSET        40
#define SA_SYMLINK_OFFSET       160

#define ZIO_OBJSET_MAC_LEN              32

/*
 * Intent log header - this on disk structure holds fields to manage
 * the log.  All fields are 64 bit to easily handle cross architectures.
 */
typedef struct zil_header {
        uint64_t zh_claim_txg;  /* txg in which log blocks were claimed */
        uint64_t zh_replay_seq; /* highest replayed sequence number */
        blkptr_t zh_log;        /* log chain */
        uint64_t zh_claim_seq;  /* highest claimed sequence number */
        uint64_t zh_pad[5];
} zil_header_t;

#define OBJSET_PHYS_SIZE_V2 2048
#define OBJSET_PHYS_SIZE_V3 4096

typedef struct objset_phys {
        dnode_phys_t os_meta_dnode;
        zil_header_t os_zil_header;
        uint64_t os_type;
        uint64_t os_flags;
        uint8_t os_portable_mac[ZIO_OBJSET_MAC_LEN];
        uint8_t os_local_mac[ZIO_OBJSET_MAC_LEN];
        char os_pad0[OBJSET_PHYS_SIZE_V2 - sizeof (dnode_phys_t)*3 -
                sizeof (zil_header_t) - sizeof (uint64_t)*2 -
                2*ZIO_OBJSET_MAC_LEN];
        dnode_phys_t os_userused_dnode;
        dnode_phys_t os_groupused_dnode;
        dnode_phys_t os_projectused_dnode;
        char os_pad1[OBJSET_PHYS_SIZE_V3 - OBJSET_PHYS_SIZE_V2 -
            sizeof (dnode_phys_t)];
} objset_phys_t;

typedef struct dsl_dir_phys {
        uint64_t dd_creation_time; /* not actually used */
        uint64_t dd_head_dataset_obj;
        uint64_t dd_parent_obj;
        uint64_t dd_clone_parent_obj;
        uint64_t dd_child_dir_zapobj;
        /*
         * how much space our children are accounting for; for leaf
         * datasets, == physical space used by fs + snaps
         */
        uint64_t dd_used_bytes;
        uint64_t dd_compressed_bytes;
        uint64_t dd_uncompressed_bytes;
        /* Administrative quota setting */
        uint64_t dd_quota;
        /* Administrative reservation setting */
        uint64_t dd_reserved;
        uint64_t dd_props_zapobj;
        uint64_t dd_pad[21]; /* pad out to 256 bytes for good measure */
} dsl_dir_phys_t;

typedef struct dsl_dataset_phys {
        uint64_t ds_dir_obj;
        uint64_t ds_prev_snap_obj;
        uint64_t ds_prev_snap_txg;
        uint64_t ds_next_snap_obj;
        uint64_t ds_snapnames_zapobj;   /* zap obj of snaps; ==0 for snaps */
        uint64_t ds_num_children;       /* clone/snap children; ==0 for head */
        uint64_t ds_creation_time;      /* seconds since 1970 */
        uint64_t ds_creation_txg;
        uint64_t ds_deadlist_obj;
        uint64_t ds_used_bytes;
        uint64_t ds_compressed_bytes;
        uint64_t ds_uncompressed_bytes;
        uint64_t ds_unique_bytes;       /* only relevant to snapshots */
        /*
         * The ds_fsid_guid is a 56-bit ID that can change to avoid
         * collisions.  The ds_guid is a 64-bit ID that will never
         * change, so there is a small probability that it will collide.
         */
        uint64_t ds_fsid_guid;
        uint64_t ds_guid;
        uint64_t ds_flags;
        blkptr_t ds_bp;
        uint64_t ds_pad[8]; /* pad out to 320 bytes for good measure */
} dsl_dataset_phys_t;

/*
 * The names of zap entries in the DIRECTORY_OBJECT of the MOS.
 */
#define DMU_POOL_DIRECTORY_OBJECT       1
#define DMU_POOL_CONFIG                 "config"
#define DMU_POOL_FEATURES_FOR_READ      "features_for_read"
#define DMU_POOL_ROOT_DATASET           "root_dataset"
#define DMU_POOL_SYNC_BPLIST            "sync_bplist"
#define DMU_POOL_ERRLOG_SCRUB           "errlog_scrub"
#define DMU_POOL_ERRLOG_LAST            "errlog_last"
#define DMU_POOL_SPARES                 "spares"
#define DMU_POOL_DEFLATE                "deflate"
#define DMU_POOL_HISTORY                "history"
#define DMU_POOL_PROPS                  "pool_props"
#define DMU_POOL_CHECKSUM_SALT          "org.illumos:checksum_salt"
#define DMU_POOL_REMOVING               "com.delphix:removing"
#define DMU_POOL_OBSOLETE_BPOBJ         "com.delphix:obsolete_bpobj"
#define DMU_POOL_CONDENSING_INDIRECT    "com.delphix:condensing_indirect"
#define DMU_POOL_ZPOOL_CHECKPOINT       "com.delphix:zpool_checkpoint"

#define ZAP_MAGIC 0x2F52AB2ABULL

#define FZAP_BLOCK_SHIFT(zap)   ((zap)->zap_block_shift)

#define ZAP_MAXCD               (uint32_t)(-1)
#define ZAP_HASHBITS            28
#define MZAP_ENT_LEN            64
#define MZAP_NAME_LEN           (MZAP_ENT_LEN - 8 - 4 - 2)
#define MZAP_MAX_BLKSZ          SPA_OLD_MAXBLOCKSIZE

typedef struct mzap_ent_phys {
        uint64_t mze_value;
        uint32_t mze_cd;
        uint16_t mze_pad;       /* in case we want to chain them someday */
        char mze_name[MZAP_NAME_LEN];
} mzap_ent_phys_t;

typedef struct mzap_phys {
        uint64_t mz_block_type; /* ZBT_MICRO */
        uint64_t mz_salt;
        uint64_t mz_normflags;
        uint64_t mz_pad[5];
        mzap_ent_phys_t mz_chunk[1];
        /* actually variable size depending on block size */
} mzap_phys_t;

/*
 * The (fat) zap is stored in one object. It is an array of
 * 1<<FZAP_BLOCK_SHIFT byte blocks. The layout looks like one of:
 *
 * ptrtbl fits in first block:
 *      [zap_phys_t zap_ptrtbl_shift < 6] [zap_leaf_t] ...
 *
 * ptrtbl too big for first block:
 *      [zap_phys_t zap_ptrtbl_shift >= 6] [zap_leaf_t] [ptrtbl] ...
 *
 */

#define ZBT_LEAF                ((1ULL << 63) + 0)
#define ZBT_HEADER              ((1ULL << 63) + 1)
#define ZBT_MICRO               ((1ULL << 63) + 3)
/* any other values are ptrtbl blocks */

/*
 * the embedded pointer table takes up half a block:
 * block size / entry size (2^3) / 2
 */
#define ZAP_EMBEDDED_PTRTBL_SHIFT(zap) (FZAP_BLOCK_SHIFT(zap) - 3 - 1)

/*
 * The embedded pointer table starts half-way through the block.  Since
 * the pointer table itself is half the block, it starts at (64-bit)
 * word number (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap)).
 */
#define ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) \
        ((uint64_t *)(zap)->zap_phys) \
        [(idx) + (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap))]

/*
 * TAKE NOTE:
 * If zap_phys_t is modified, zap_byteswap() must be modified.
 */
typedef struct zap_phys {
        uint64_t zap_block_type;        /* ZBT_HEADER */
        uint64_t zap_magic;             /* ZAP_MAGIC */

        struct zap_table_phys {
                uint64_t zt_blk;        /* starting block number */
                uint64_t zt_numblks;    /* number of blocks */
                uint64_t zt_shift;      /* bits to index it */
                uint64_t zt_nextblk;    /* next (larger) copy start block */
                uint64_t zt_blks_copied; /* number source blocks copied */
        } zap_ptrtbl;

        uint64_t zap_freeblk;           /* the next free block */
        uint64_t zap_num_leafs;         /* number of leafs */
        uint64_t zap_num_entries;       /* number of entries */
        uint64_t zap_salt;              /* salt to stir into hash function */
        uint64_t zap_normflags;         /* flags for u8_textprep_str() */
        uint64_t zap_flags;             /* zap_flags_t */
        /*
         * This structure is followed by padding, and then the embedded
         * pointer table.  The embedded pointer table takes up second
         * half of the block.  It is accessed using the
         * ZAP_EMBEDDED_PTRTBL_ENT() macro.
         */
} zap_phys_t;

typedef struct zap_table_phys zap_table_phys_t;

struct spa;
typedef struct fat_zap {
        int zap_block_shift;                    /* block size shift */
        zap_phys_t *zap_phys;
        const struct spa *zap_spa;
        const dnode_phys_t *zap_dnode;
} fat_zap_t;

#define ZAP_LEAF_MAGIC 0x2AB1EAF

/* chunk size = 24 bytes */
#define ZAP_LEAF_CHUNKSIZE 24

/*
 * The amount of space available for chunks is:
 * block size (1<<l->l_bs) - hash entry size (2) * number of hash
 * entries - header space (2*chunksize)
 */
#define ZAP_LEAF_NUMCHUNKS(l) \
        (((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
        ZAP_LEAF_CHUNKSIZE - 2)

/*
 * The amount of space within the chunk available for the array is:
 * chunk size - space for type (1) - space for next pointer (2)
 */
#define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)

#define ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
        (((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)

/*
 * Low water mark:  when there are only this many chunks free, start
 * growing the ptrtbl.  Ideally, this should be larger than a
 * "reasonably-sized" entry.  20 chunks is more than enough for the
 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
 * while still being only around 3% for 16k blocks.
 */
#define ZAP_LEAF_LOW_WATER (20)

/*
 * The leaf hash table has block size / 2^5 (32) number of entries,
 * which should be more than enough for the maximum number of entries,
 * which is less than block size / CHUNKSIZE (24) / minimum number of
 * chunks per entry (3).
 */
#define ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
#define ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))

/*
 * The chunks start immediately after the hash table.  The end of the
 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
 * chunk_t.
 */
#define ZAP_LEAF_CHUNK(l, idx) \
        ((zap_leaf_chunk_t *) \
        ((l)->l_phys->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
#define ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)

typedef enum zap_chunk_type {
        ZAP_CHUNK_FREE = 253,
        ZAP_CHUNK_ENTRY = 252,
        ZAP_CHUNK_ARRAY = 251,
        ZAP_CHUNK_TYPE_MAX = 250
} zap_chunk_type_t;

/*
 * TAKE NOTE:
 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
 */
typedef struct zap_leaf_phys {
        struct zap_leaf_header {
                uint64_t lh_block_type;         /* ZBT_LEAF */
                uint64_t lh_pad1;
                uint64_t lh_prefix;             /* hash prefix of this leaf */
                uint32_t lh_magic;              /* ZAP_LEAF_MAGIC */
                uint16_t lh_nfree;              /* number free chunks */
                uint16_t lh_nentries;           /* number of entries */
                uint16_t lh_prefix_len;         /* num bits used to id this */

/* above is accessable to zap, below is zap_leaf private */

                uint16_t lh_freelist;           /* chunk head of free list */
                uint8_t lh_pad2[12];
        } l_hdr; /* 2 24-byte chunks */

        /*
         * The header is followed by a hash table with
         * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
         * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
         * zap_leaf_chunk structures.  These structures are accessed
         * with the ZAP_LEAF_CHUNK() macro.
         */

        uint16_t l_hash[1];
} zap_leaf_phys_t;

typedef union zap_leaf_chunk {
        struct zap_leaf_entry {
                uint8_t le_type;                /* always ZAP_CHUNK_ENTRY */
                uint8_t le_value_intlen;        /* size of ints */
                uint16_t le_next;               /* next entry in hash chain */
                uint16_t le_name_chunk;         /* first chunk of the name */
                uint16_t le_name_numints;       /* bytes in name, incl null */
                uint16_t le_value_chunk;        /* first chunk of the value */
                uint16_t le_value_numints;      /* value length in ints */
                uint32_t le_cd;                 /* collision differentiator */
                uint64_t le_hash;               /* hash value of the name */
        } l_entry;
        struct zap_leaf_array {
                uint8_t la_type;                /* always ZAP_CHUNK_ARRAY */
                uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
                uint16_t la_next;               /* next blk or CHAIN_END */
        } l_array;
        struct zap_leaf_free {
                uint8_t lf_type;                /* always ZAP_CHUNK_FREE */
                uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
                uint16_t lf_next;       /* next in free list, or CHAIN_END */
        } l_free;
} zap_leaf_chunk_t;

typedef struct zap_leaf {
        int l_bs;                       /* block size shift */
        zap_leaf_phys_t *l_phys;
} zap_leaf_t;

/*
 * Define special zfs pflags
 */
#define ZFS_XATTR       0x1             /* is an extended attribute */
#define ZFS_INHERIT_ACE 0x2             /* ace has inheritable ACEs */
#define ZFS_ACL_TRIVIAL 0x4             /* files ACL is trivial */

#define MASTER_NODE_OBJ 1

/*
 * special attributes for master node.
 */

#define ZFS_FSID                "FSID"
#define ZFS_UNLINKED_SET        "DELETE_QUEUE"
#define ZFS_ROOT_OBJ            "ROOT"
#define ZPL_VERSION_OBJ         "VERSION"
#define ZFS_PROP_BLOCKPERPAGE   "BLOCKPERPAGE"
#define ZFS_PROP_NOGROWBLOCKS   "NOGROWBLOCKS"

#define ZFS_FLAG_BLOCKPERPAGE   0x1
#define ZFS_FLAG_NOGROWBLOCKS   0x2

/*
 * ZPL version - rev'd whenever an incompatible on-disk format change
 * occurs.  Independent of SPA/DMU/ZAP versioning.
 */

#define ZPL_VERSION             1ULL

/*
 * The directory entry has the type (currently unused on Solaris) in the
 * top 4 bits, and the object number in the low 48 bits.  The "middle"
 * 12 bits are unused.
 */
#define ZFS_DIRENT_TYPE(de) BF64_GET(de, 60, 4)
#define ZFS_DIRENT_OBJ(de) BF64_GET(de, 0, 48)
#define ZFS_DIRENT_MAKE(type, obj) (((uint64_t)type << 60) | obj)

typedef struct ace {
        uid_t           a_who;          /* uid or gid */
        uint32_t        a_access_mask;  /* read,write,... */
        uint16_t        a_flags;        /* see below */
        uint16_t        a_type;         /* allow or deny */
} ace_t;

#define ACE_SLOT_CNT    6

typedef struct zfs_znode_acl {
        uint64_t        z_acl_extern_obj;         /* ext acl pieces */
        uint32_t        z_acl_count;              /* Number of ACEs */
        uint16_t        z_acl_version;            /* acl version */
        uint16_t        z_acl_pad;                /* pad */
        ace_t           z_ace_data[ACE_SLOT_CNT]; /* 6 standard ACEs */
} zfs_znode_acl_t;

/*
 * This is the persistent portion of the znode.  It is stored
 * in the "bonus buffer" of the file.  Short symbolic links
 * are also stored in the bonus buffer.
 */
typedef struct znode_phys {
        uint64_t zp_atime[2];           /*  0 - last file access time */
        uint64_t zp_mtime[2];           /* 16 - last file modification time */
        uint64_t zp_ctime[2];           /* 32 - last file change time */
        uint64_t zp_crtime[2];          /* 48 - creation time */
        uint64_t zp_gen;                /* 64 - generation (txg of creation) */
        uint64_t zp_mode;               /* 72 - file mode bits */
        uint64_t zp_size;               /* 80 - size of file */
        uint64_t zp_parent;             /* 88 - directory parent (`..') */
        uint64_t zp_links;              /* 96 - number of links to file */
        uint64_t zp_xattr;              /* 104 - DMU object for xattrs */
        uint64_t zp_rdev;               /* 112 - dev_t for VBLK & VCHR files */
        uint64_t zp_flags;              /* 120 - persistent flags */
        uint64_t zp_uid;                /* 128 - file owner */
        uint64_t zp_gid;                /* 136 - owning group */
        uint64_t zp_pad[4];             /* 144 - future */
        zfs_znode_acl_t zp_acl;         /* 176 - 263 ACL */
        /*
         * Data may pad out any remaining bytes in the znode buffer, eg:
         *
         * |<---------------------- dnode_phys (512) ------------------------>|
         * |<-- dnode (192) --->|<----------- "bonus" buffer (320) ---------->|
         *                      |<---- znode (264) ---->|<---- data (56) ---->|
         *
         * At present, we only use this space to store symbolic links.
         */
} znode_phys_t;

/*
 * In-core vdev representation.
 */
struct vdev;
struct spa;
typedef int vdev_phys_read_t(struct vdev *, void *, off_t, void *, size_t);
typedef int vdev_phys_write_t(struct vdev *, off_t, void *, size_t);
typedef int vdev_read_t(struct vdev *, const blkptr_t *, void *, off_t, size_t);

typedef STAILQ_HEAD(vdev_list, vdev) vdev_list_t;

typedef struct vdev_indirect_mapping_entry_phys {
        /*
         * Decode with DVA_MAPPING_* macros.
         * Contains:
         *   the source offset (low 63 bits)
         *   the one-bit "mark", used for garbage collection (by zdb)
         */
        uint64_t vimep_src;

        /*
         * Note: the DVA's asize is 24 bits, and can thus store ranges
         * up to 8GB.
         */
        dva_t   vimep_dst;
} vdev_indirect_mapping_entry_phys_t;

#define DVA_MAPPING_GET_SRC_OFFSET(vimep)       \
        BF64_GET_SB((vimep)->vimep_src, 0, 63, SPA_MINBLOCKSHIFT, 0)
#define DVA_MAPPING_SET_SRC_OFFSET(vimep, x)    \
        BF64_SET_SB((vimep)->vimep_src, 0, 63, SPA_MINBLOCKSHIFT, 0, x)

typedef struct vdev_indirect_mapping_entry {
        vdev_indirect_mapping_entry_phys_t      vime_mapping;
        uint32_t                                vime_obsolete_count;
        list_node_t                             vime_node;
} vdev_indirect_mapping_entry_t;

/*
 * This is stored in the bonus buffer of the mapping object, see comment of
 * vdev_indirect_config for more details.
 */
typedef struct vdev_indirect_mapping_phys {
        uint64_t        vimp_max_offset;
        uint64_t        vimp_bytes_mapped;
        uint64_t        vimp_num_entries; /* number of v_i_m_entry_phys_t's */

        /*
         * For each entry in the mapping object, this object contains an
         * entry representing the number of bytes of that mapping entry
         * that were no longer in use by the pool at the time this indirect
         * vdev was last condensed.
         */
        uint64_t        vimp_counts_object;
} vdev_indirect_mapping_phys_t;

#define VDEV_INDIRECT_MAPPING_SIZE_V0   (3 * sizeof (uint64_t))

typedef struct vdev_indirect_mapping {
        uint64_t        vim_object;
        boolean_t       vim_havecounts;

        /* vim_entries segment offset currently in memory. */
        uint64_t        vim_entry_offset;
        /* vim_entries segment size. */
        size_t          vim_num_entries;

        /* Needed by dnode_read() */
        const void      *vim_spa;
        dnode_phys_t    *vim_dn;

        /*
         * An ordered array of mapping entries, sorted by source offset.
         * Note that vim_entries is needed during a removal (and contains
         * mappings that have been synced to disk so far) to handle frees
         * from the removing device.
         */
        vdev_indirect_mapping_entry_phys_t *vim_entries;
        objset_phys_t   *vim_objset;
        vdev_indirect_mapping_phys_t    *vim_phys;
} vdev_indirect_mapping_t;

/*
 * On-disk indirect vdev state.
 *
 * An indirect vdev is described exclusively in the MOS config of a pool.
 * The config for an indirect vdev includes several fields, which are
 * accessed in memory by a vdev_indirect_config_t.
 */
typedef struct vdev_indirect_config {
        /*
         * Object (in MOS) which contains the indirect mapping. This object
         * contains an array of vdev_indirect_mapping_entry_phys_t ordered by
         * vimep_src. The bonus buffer for this object is a
         * vdev_indirect_mapping_phys_t. This object is allocated when a vdev
         * removal is initiated.
         *
         * Note that this object can be empty if none of the data on the vdev
         * has been copied yet.
         */
        uint64_t        vic_mapping_object;

        /*
         * Object (in MOS) which contains the birth times for the mapping
         * entries. This object contains an array of
         * vdev_indirect_birth_entry_phys_t sorted by vibe_offset. The bonus
         * buffer for this object is a vdev_indirect_birth_phys_t. This object
         * is allocated when a vdev removal is initiated.
         *
         * Note that this object can be empty if none of the vdev has yet been
         * copied.
         */
        uint64_t        vic_births_object;

/*
 * This is the vdev ID which was removed previous to this vdev, or
 * UINT64_MAX if there are no previously removed vdevs.
 */
        uint64_t        vic_prev_indirect_vdev;
} vdev_indirect_config_t;

typedef struct vdev {
        STAILQ_ENTRY(vdev) v_childlink; /* link in parent's child list */
        STAILQ_ENTRY(vdev) v_alllink;   /* link in global vdev list */
        vdev_list_t     v_children;     /* children of this vdev */
        const char      *v_name;        /* vdev name */
        uint64_t        v_guid;         /* vdev guid */
        uint64_t        v_id;           /* index in parent */
        uint64_t        v_psize;        /* physical device capacity */
        int             v_ashift;       /* offset to block shift */
        int             v_nparity;      /* # parity for raidz */
        struct vdev     *v_top;         /* parent vdev */
        size_t          v_nchildren;    /* # children */
        vdev_state_t    v_state;        /* current state */
        vdev_phys_read_t *v_phys_read;  /* read from raw leaf vdev */
        vdev_phys_write_t *v_phys_write; /* write to raw leaf vdev */
        vdev_read_t     *v_read;        /* read from vdev */
        void            *v_priv;        /* data for read/write function */
        boolean_t       v_islog;
        struct spa      *v_spa;         /* link to spa */
        /*
         * Values stored in the config for an indirect or removing vdev.
         */
        vdev_indirect_config_t vdev_indirect_config;
        vdev_indirect_mapping_t *v_mapping;
} vdev_t;

/*
 * In-core pool representation.
 */
typedef STAILQ_HEAD(spa_list, spa) spa_list_t;

typedef struct spa {
        STAILQ_ENTRY(spa) spa_link;     /* link in global pool list */
        char            *spa_name;      /* pool name */
        uint64_t        spa_guid;       /* pool guid */
        uint64_t        spa_txg;        /* most recent transaction */
        struct uberblock *spa_uberblock;        /* best uberblock so far */
        vdev_t          *spa_root_vdev; /* toplevel vdev container */
        objset_phys_t   *spa_mos;       /* MOS for this pool */
        zio_cksum_salt_t spa_cksum_salt;        /* secret salt for cksum */
        void            *spa_cksum_tmpls[ZIO_CHECKSUM_FUNCTIONS];
        boolean_t       spa_with_log;   /* this pool has log */

        struct uberblock spa_uberblock_master;  /* best uberblock so far */
        objset_phys_t   spa_mos_master;         /* MOS for this pool */
        struct uberblock spa_uberblock_checkpoint; /* checkpoint uberblock */
        objset_phys_t   spa_mos_checkpoint;     /* Checkpoint MOS */
        void            *spa_bootenv;           /* bootenv from pool label */
} spa_t;

/* IO related arguments. */
typedef struct zio {
        spa_t           *io_spa;
        blkptr_t        *io_bp;
        void            *io_data;
        uint64_t        io_size;
        uint64_t        io_offset;

        /* Stuff for the vdev stack */
        vdev_t          *io_vd;
        void            *io_vsd;

        int             io_error;
} zio_t;

static void decode_embedded_bp_compressed(const blkptr_t *, void *);

#endif /* _ZFSIMPL_H_ */