boot/zfs/zfsimpl.c

	zfsimpl.c revision 199767f8919635c4928607450d9e0abb932109ce
/*-
 * Copyright (c) 2007 Doug Rabson
 * All rights reserved.
 *
 * 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.
 */

#include <sys/cdefs.h>

/*
 *  Stand-alone ZFS file reader.
 */

#include <sys/stat.h>
#include <sys/stdint.h>

#include "zfsimpl.h"
#include "zfssubr.c"


struct zfsmount {
    const spa_t *spa;
    objset_phys_t   objset;
    uint64_t    rootobj;
};

/*
 * List of all vdevs, chained through v_alllink.
 */
static vdev_list_t zfs_vdevs;

 /*
 * List of ZFS features supported for read
 */
static const char *features_for_read[] = {
    "org.illumos:lz4_compress",
    "com.delphix:hole_birth",
    "com.delphix:extensible_dataset",
    "com.delphix:embedded_data",
    "org.open-zfs:large_blocks",
    "org.illumos:sha512",
    NULL
};

/*
 * List of all pools, chained through spa_link.
 */
static spa_list_t zfs_pools;

static uint64_t zfs_crc64_table[256];
static const dnode_phys_t *dnode_cache_obj = 0;
static uint64_t dnode_cache_bn;
static char *dnode_cache_buf;
static char *zap_scratch;
static char *zfs_temp_buf, *zfs_temp_end, *zfs_temp_ptr;

#define TEMP_SIZE   (1024 * 1024)

static int zio_read(const spa_t *spa, const blkptr_t *bp, void *buf);
static int zfs_get_root(const spa_t *spa, uint64_t *objid);
static int zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result);

static void
zfs_init(void)
{
    STAILQ_INIT(&zfs_vdevs);
    STAILQ_INIT(&zfs_pools);

    zfs_temp_buf = malloc(TEMP_SIZE);
    zfs_temp_end = zfs_temp_buf + TEMP_SIZE;
    zfs_temp_ptr = zfs_temp_buf;
    dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
    zap_scratch = malloc(SPA_MAXBLOCKSIZE);

    zfs_init_crc();
}

static void *
zfs_alloc(size_t size)
{
    char *ptr;

    if (zfs_temp_ptr + size > zfs_temp_end) {
        printf("ZFS: out of temporary buffer space\n");
        for (;;) ;
    }
    ptr = zfs_temp_ptr;
    zfs_temp_ptr += size;

    return (ptr);
}

static void
zfs_free(void *ptr, size_t size)
{

    zfs_temp_ptr -= size;
    if (zfs_temp_ptr != ptr) {
        printf("ZFS: zfs_alloc()/zfs_free() mismatch\n");
        for (;;) ;
    }
}

static int
xdr_int(const unsigned char **xdr, int *ip)
{
    *ip = ((*xdr)[0] << 24)
        | ((*xdr)[1] << 16)
        | ((*xdr)[2] << 8)
        | ((*xdr)[3] << 0);
    (*xdr) += 4;
    return (0);
}

static int
xdr_u_int(const unsigned char **xdr, u_int *ip)
{
    *ip = ((*xdr)[0] << 24)
        | ((*xdr)[1] << 16)
        | ((*xdr)[2] << 8)
        | ((*xdr)[3] << 0);
    (*xdr) += 4;
    return (0);
}

static int
xdr_uint64_t(const unsigned char **xdr, uint64_t *lp)
{
    u_int hi, lo;

    xdr_u_int(xdr, &hi);
    xdr_u_int(xdr, &lo);
    *lp = (((uint64_t) hi) << 32) | lo;
    return (0);
}

static int
nvlist_find(const unsigned char *nvlist, const char *name, int type,
        int* elementsp, void *valuep)
{
    const unsigned char *p, *pair;
    int junk;
    int encoded_size, decoded_size;

    p = nvlist;
    xdr_int(&p, &junk);
    xdr_int(&p, &junk);

    pair = p;
    xdr_int(&p, &encoded_size);
    xdr_int(&p, &decoded_size);
    while (encoded_size && decoded_size) {
        int namelen, pairtype, elements;
        const char *pairname;

        xdr_int(&p, &namelen);
        pairname = (const char*) p;
        p += roundup(namelen, 4);
        xdr_int(&p, &pairtype);

        if (!memcmp(name, pairname, namelen) && type == pairtype) {
            xdr_int(&p, &elements);
            if (elementsp)
                *elementsp = elements;
            if (type == DATA_TYPE_UINT64) {
                xdr_uint64_t(&p, (uint64_t *) valuep);
                return (0);
            } else if (type == DATA_TYPE_STRING) {
                int len;
                xdr_int(&p, &len);
                (*(const char**) valuep) = (const char*) p;
                return (0);
            } else if (type == DATA_TYPE_NVLIST
                   || type == DATA_TYPE_NVLIST_ARRAY) {
                (*(const unsigned char**) valuep) =
                     (const unsigned char*) p;
                return (0);
            } else {
                return (EIO);
            }
        } else {
            /*
             * Not the pair we are looking for, skip to the next one.
             */
            p = pair + encoded_size;
        }

        pair = p;
        xdr_int(&p, &encoded_size);
        xdr_int(&p, &decoded_size);
    }

    return (EIO);
}

static int
nvlist_check_features_for_read(const unsigned char *nvlist)
{
    const unsigned char *p, *pair;
    int junk;
    int encoded_size, decoded_size;
    int rc;

    rc = 0;

    p = nvlist;
    xdr_int(&p, &junk);
    xdr_int(&p, &junk);

    pair = p;
    xdr_int(&p, &encoded_size);
    xdr_int(&p, &decoded_size);
    while (encoded_size && decoded_size) {
        int namelen, pairtype;
        const char *pairname;
        int i, found;

        found = 0;

        xdr_int(&p, &namelen);
        pairname = (const char*) p;
        p += roundup(namelen, 4);
        xdr_int(&p, &pairtype);

        for (i = 0; features_for_read[i] != NULL; i++) {
            if (!memcmp(pairname, features_for_read[i], namelen)) {
                found = 1;
                break;
            }
        }

        if (!found) {
            printf("ZFS: unsupported feature: %s\n", pairname);
            rc = EIO;
        }

        p = pair + encoded_size;

        pair = p;
        xdr_int(&p, &encoded_size);
        xdr_int(&p, &decoded_size);
    }

    return (rc);
}

/*
 * Return the next nvlist in an nvlist array.
 */
static const unsigned char *
nvlist_next(const unsigned char *nvlist)
{
    const unsigned char *p, *pair;
    int junk;
    int encoded_size, decoded_size;

    p = nvlist;
    xdr_int(&p, &junk);
    xdr_int(&p, &junk);

    pair = p;
    xdr_int(&p, &encoded_size);
    xdr_int(&p, &decoded_size);
    while (encoded_size && decoded_size) {
        p = pair + encoded_size;

        pair = p;
        xdr_int(&p, &encoded_size);
        xdr_int(&p, &decoded_size);
    }

    return p;
}

#ifdef TEST

static const unsigned char *
nvlist_print(const unsigned char *nvlist, unsigned int indent)
{
    static const char* typenames[] = {
        "DATA_TYPE_UNKNOWN",
        "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"
    };

    unsigned int i, j;
    const unsigned char *p, *pair;
    int junk;
    int encoded_size, decoded_size;

    p = nvlist;
    xdr_int(&p, &junk);
    xdr_int(&p, &junk);

    pair = p;
    xdr_int(&p, &encoded_size);
    xdr_int(&p, &decoded_size);
    while (encoded_size && decoded_size) {
        int namelen, pairtype, elements;
        const char *pairname;

        xdr_int(&p, &namelen);
        pairname = (const char*) p;
        p += roundup(namelen, 4);
        xdr_int(&p, &pairtype);

        for (i = 0; i < indent; i++)
            printf(" ");
        printf("%s %s", typenames[pairtype], pairname);

        xdr_int(&p, &elements);
        switch (pairtype) {
        case DATA_TYPE_UINT64: {
            uint64_t val;
            xdr_uint64_t(&p, &val);
            printf(" = 0x%jx\n", (uintmax_t)val);
            break;
        }

        case DATA_TYPE_STRING: {
            int len;
            xdr_int(&p, &len);
            printf(" = \"%s\"\n", p);
            break;
        }

        case DATA_TYPE_NVLIST:
            printf("\n");
            nvlist_print(p, indent + 1);
            break;

        case DATA_TYPE_NVLIST_ARRAY:
            for (j = 0; j < elements; j++) {
                printf("[%d]\n", j);
                p = nvlist_print(p, indent + 1);
                if (j != elements - 1) {
                    for (i = 0; i < indent; i++)
                        printf(" ");
                    printf("%s %s", typenames[pairtype], pairname);
                }
            }
            break;

        default:
            printf("\n");
        }

        p = pair + encoded_size;

        pair = p;
        xdr_int(&p, &encoded_size);
        xdr_int(&p, &decoded_size);
    }

    return p;
}

#endif

static int
vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
    off_t offset, size_t size)
{
    size_t psize;
    int rc;

    if (!vdev->v_phys_read)
        return (EIO);

    if (bp) {
        psize = BP_GET_PSIZE(bp);
    } else {
        psize = size;
    }

    /*printf("ZFS: reading %d bytes at 0x%jx to %p\n", psize, (uintmax_t)offset, buf);*/
    rc = vdev->v_phys_read(vdev, vdev->v_read_priv, offset, buf, psize);
    if (rc)
        return (rc);
    if (bp && zio_checksum_verify(bp, buf))
        return (EIO);

    return (0);
}

static int
vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
    off_t offset, size_t bytes)
{

    return (vdev_read_phys(vdev, bp, buf,
        offset + VDEV_LABEL_START_SIZE, bytes));
}


static int
vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
    off_t offset, size_t bytes)
{
    vdev_t *kid;
    int rc;

    rc = EIO;
    STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
        if (kid->v_state != VDEV_STATE_HEALTHY)
            continue;
        rc = kid->v_read(kid, bp, buf, offset, bytes);
        if (!rc)
            return (0);
    }

    return (rc);
}

static int
vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
    off_t offset, size_t bytes)
{
    vdev_t *kid;

    /*
     * Here we should have two kids:
     * First one which is the one we are replacing and we can trust
     * only this one to have valid data, but it might not be present.
     * Second one is that one we are replacing with. It is most likely
     * healthy, but we can't trust it has needed data, so we won't use it.
     */
    kid = STAILQ_FIRST(&vdev->v_children);
    if (kid == NULL)
        return (EIO);
    if (kid->v_state != VDEV_STATE_HEALTHY)
        return (EIO);
    return (kid->v_read(kid, bp, buf, offset, bytes));
}

static vdev_t *
vdev_find(uint64_t guid)
{
    vdev_t *vdev;

    STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
        if (vdev->v_guid == guid)
            return (vdev);

    return (0);
}

static vdev_t *
vdev_create(uint64_t guid, vdev_read_t *vdev_read)
{
    vdev_t *vdev;

    vdev = malloc(sizeof(vdev_t));
    memset(vdev, 0, sizeof(vdev_t));
    STAILQ_INIT(&vdev->v_children);
    vdev->v_guid = guid;
    vdev->v_state = VDEV_STATE_OFFLINE;
    vdev->v_read = vdev_read;
    vdev->v_phys_read = 0;
    vdev->v_read_priv = 0;
    STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);

    return (vdev);
}

static int
vdev_init_from_nvlist(const unsigned char *nvlist, vdev_t *pvdev,
    vdev_t **vdevp, int is_newer)
{
    int rc;
    uint64_t guid, id, ashift, nparity;
    const char *type;
    const char *path;
    vdev_t *vdev, *kid;
    const unsigned char *kids;
    int nkids, i, is_new;
    uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;

    if (nvlist_find(nvlist, ZPOOL_CONFIG_GUID,
            DATA_TYPE_UINT64, 0, &guid)
        || nvlist_find(nvlist, ZPOOL_CONFIG_ID,
               DATA_TYPE_UINT64, 0, &id)
        || nvlist_find(nvlist, ZPOOL_CONFIG_TYPE,
               DATA_TYPE_STRING, 0, &type)) {
        printf("ZFS: can't find vdev details\n");
        return (ENOENT);
    }

    if (strcmp(type, VDEV_TYPE_MIRROR)
        && strcmp(type, VDEV_TYPE_DISK)
#ifdef ZFS_TEST
        && strcmp(type, VDEV_TYPE_FILE)
#endif
        && strcmp(type, VDEV_TYPE_RAIDZ)
        && strcmp(type, VDEV_TYPE_REPLACING)) {
        printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
        return (EIO);
    }

    is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;

    nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, 0,
            &is_offline);
    nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, 0,
            &is_removed);
    nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, 0,
            &is_faulted);
    nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64, 0,
            &is_degraded);
    nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64, 0,
            &isnt_present);

    vdev = vdev_find(guid);
    if (!vdev) {
        is_new = 1;

        if (!strcmp(type, VDEV_TYPE_MIRROR))
            vdev = vdev_create(guid, vdev_mirror_read);
        else if (!strcmp(type, VDEV_TYPE_RAIDZ))
            vdev = vdev_create(guid, vdev_raidz_read);
        else if (!strcmp(type, VDEV_TYPE_REPLACING))
            vdev = vdev_create(guid, vdev_replacing_read);
        else
            vdev = vdev_create(guid, vdev_disk_read);

        vdev->v_id = id;
        vdev->v_top = pvdev != NULL ? pvdev : vdev;
        if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
            DATA_TYPE_UINT64, 0, &ashift) == 0)
            vdev->v_ashift = ashift;
        else
            vdev->v_ashift = 0;
        if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
            DATA_TYPE_UINT64, 0, &nparity) == 0)
            vdev->v_nparity = nparity;
        else
            vdev->v_nparity = 0;
        if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
                DATA_TYPE_STRING, 0, &path) == 0) {
            if (strncmp(path, "/dev/dsk/", 9) == 0)
                path += 9;
            vdev->v_name = strdup(path);
            if (nvlist_find(nvlist, ZPOOL_CONFIG_PHYS_PATH,
                DATA_TYPE_STRING, 0, &path) == 0)
                vdev->v_phys_path = strdup(path);
            else
                vdev->v_phys_path = NULL;
            if (nvlist_find(nvlist, ZPOOL_CONFIG_DEVID,
                DATA_TYPE_STRING, 0, &path) == 0)
                vdev->v_devid = strdup(path);
            else
                vdev->v_devid = NULL;
        } else {
            if (!strcmp(type, "raidz")) {
                if (vdev->v_nparity == 1)
                    vdev->v_name = "raidz1";
                else if (vdev->v_nparity == 2)
                    vdev->v_name = "raidz2";
                else if (vdev->v_nparity == 3)
                    vdev->v_name = "raidz3";
                else {
                    printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
                    return (EIO);
                }
            } else {
                vdev->v_name = strdup(type);
            }
        }
    } else {
        is_new = 0;
    }

    if (is_new || is_newer) {
        /*
         * This is either new vdev or we've already seen this vdev,
         * but from an older vdev label, so let's refresh its state
         * from the newer label.
         */
        if (is_offline)
            vdev->v_state = VDEV_STATE_OFFLINE;
        else if (is_removed)
            vdev->v_state = VDEV_STATE_REMOVED;
        else if (is_faulted)
            vdev->v_state = VDEV_STATE_FAULTED;
        else if (is_degraded)
            vdev->v_state = VDEV_STATE_DEGRADED;
        else if (isnt_present)
            vdev->v_state = VDEV_STATE_CANT_OPEN;
    }

    rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN,
             DATA_TYPE_NVLIST_ARRAY, &nkids, &kids);
    /*
     * Its ok if we don't have any kids.
     */
    if (rc == 0) {
        vdev->v_nchildren = nkids;
        for (i = 0; i < nkids; i++) {
            rc = vdev_init_from_nvlist(kids, vdev, &kid, is_newer);
            if (rc)
                return (rc);
            if (is_new)
                STAILQ_INSERT_TAIL(&vdev->v_children, kid,
                           v_childlink);
            kids = nvlist_next(kids);
        }
    } else {
        vdev->v_nchildren = 0;
    }

    if (vdevp)
        *vdevp = vdev;
    return (0);
}

static void
vdev_set_state(vdev_t *vdev)
{
    vdev_t *kid;
    int good_kids;
    int bad_kids;

    /*
     * A mirror or raidz is healthy if all its kids are healthy. A
     * mirror is degraded if any of its kids is healthy; a raidz
     * is degraded if at most nparity kids are offline.
     */
    if (STAILQ_FIRST(&vdev->v_children)) {
        good_kids = 0;
        bad_kids = 0;
        STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
            if (kid->v_state == VDEV_STATE_HEALTHY)
                good_kids++;
            else
                bad_kids++;
        }
        if (bad_kids == 0) {
            vdev->v_state = VDEV_STATE_HEALTHY;
        } else {
            if (vdev->v_read == vdev_mirror_read) {
                if (good_kids) {
                    vdev->v_state = VDEV_STATE_DEGRADED;
                } else {
                    vdev->v_state = VDEV_STATE_OFFLINE;
                }
            } else if (vdev->v_read == vdev_raidz_read) {
                if (bad_kids > vdev->v_nparity) {
                    vdev->v_state = VDEV_STATE_OFFLINE;
                } else {
                    vdev->v_state = VDEV_STATE_DEGRADED;
                }
            }
        }
    }
}

static spa_t *
spa_find_by_guid(uint64_t guid)
{
    spa_t *spa;

    STAILQ_FOREACH(spa, &zfs_pools, spa_link)
        if (spa->spa_guid == guid)
            return (spa);

    return (0);
}

static spa_t *
spa_find_by_name(const char *name)
{
    spa_t *spa;

    STAILQ_FOREACH(spa, &zfs_pools, spa_link)
        if (!strcmp(spa->spa_name, name))
            return (spa);

    return (0);
}

spa_t *
spa_get_primary(void)
{
    return (STAILQ_FIRST(&zfs_pools));
}

vdev_t *
spa_get_primary_vdev(const spa_t *spa)
{
    vdev_t *vdev;
    vdev_t *kid;

    if (spa == NULL)
        spa = spa_get_primary();
    if (spa == NULL)
        return (NULL);
    vdev = STAILQ_FIRST(&spa->spa_vdevs);
    if (vdev == NULL)
        return (NULL);
    for (kid = STAILQ_FIRST(&vdev->v_children); kid != NULL;
         kid = STAILQ_FIRST(&vdev->v_children))
        vdev = kid;
    return (vdev);
}

static spa_t *
spa_create(uint64_t guid)
{
    spa_t *spa;

    spa = malloc(sizeof(spa_t));
    memset(spa, 0, sizeof(spa_t));
    STAILQ_INIT(&spa->spa_vdevs);
    spa->spa_guid = guid;
    STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);

    return (spa);
}

static const char *
state_name(vdev_state_t state)
{
    static const char* names[] = {
        "UNKNOWN",
        "CLOSED",
        "OFFLINE",
        "REMOVED",
        "CANT_OPEN",
        "FAULTED",
        "DEGRADED",
        "ONLINE"
    };
    return names[state];
}

static int
pager_printf(const char *fmt, ...)
{
    char line[80];
    va_list args;

    va_start(args, fmt);
    vsnprintf(line, sizeof (line), fmt, args);
    va_end(args);
    return (pager_output(line));
}

#define STATUS_FORMAT   "        %s %s\n"

static int
print_state(int indent, const char *name, vdev_state_t state)
{
    int i;
    char buf[512];

    buf[0] = 0;
    for (i = 0; i < indent; i++)
        strcat(buf, "  ");
    strcat(buf, name);
    return (pager_printf(STATUS_FORMAT, buf, state_name(state)));
}

static int
vdev_status(vdev_t *vdev, int indent)
{
    vdev_t *kid;
    int ret;
    ret = print_state(indent, vdev->v_name, vdev->v_state);
    if (ret != 0)
        return (ret);

    STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
        ret = vdev_status(kid, indent + 1);
        if (ret != 0)
            return (ret);
    }
    return (ret);
}

static int
spa_status(spa_t *spa)
{
    static char bootfs[ZFS_MAXNAMELEN];
    uint64_t rootid;
    vdev_t *vdev;
    int good_kids, bad_kids, degraded_kids, ret;
    vdev_state_t state;

    ret = pager_printf("  pool: %s\n", spa->spa_name);
    if (ret != 0)
        return (ret);

    if (zfs_get_root(spa, &rootid) == 0 &&
        zfs_rlookup(spa, rootid, bootfs) == 0) {
        if (bootfs[0] == '\0')
            ret = pager_printf("bootfs: %s\n", spa->spa_name);
        else
            ret = pager_printf("bootfs: %s/%s\n", spa->spa_name,
                bootfs);
        if (ret != 0)
            return (ret);
    }
    ret = pager_printf("config:\n\n");
    if (ret != 0)
        return (ret);
    ret = pager_printf(STATUS_FORMAT, "NAME", "STATE");
    if (ret != 0)
        return (ret);

    good_kids = 0;
    degraded_kids = 0;
    bad_kids = 0;
    STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
        if (vdev->v_state == VDEV_STATE_HEALTHY)
            good_kids++;
        else if (vdev->v_state == VDEV_STATE_DEGRADED)
            degraded_kids++;
        else
            bad_kids++;
    }

    state = VDEV_STATE_CLOSED;
    if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
        state = VDEV_STATE_HEALTHY;
    else if ((good_kids + degraded_kids) > 0)
        state = VDEV_STATE_DEGRADED;

    ret = print_state(0, spa->spa_name, state);
    if (ret != 0)
        return (ret);
    STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
        ret = vdev_status(vdev, 1);
        if (ret != 0)
            return (ret);
    }
    return (ret);
}

int
spa_all_status(void)
{
    spa_t *spa;
    int first = 1, ret = 0;

    STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
        if (!first) {
            ret = pager_printf("\n");
            if (ret != 0)
                return (ret);
        }
        first = 0;
        ret = spa_status(spa);
        if (ret != 0)
            return (ret);
    }
    return (ret);
}

static int
vdev_probe(vdev_phys_read_t *phys_read, void *read_priv, spa_t **spap)
{
    vdev_t vtmp;
    vdev_phys_t *vdev_label = (vdev_phys_t *) zap_scratch;
    spa_t *spa;
    vdev_t *vdev, *top_vdev, *pool_vdev;
    off_t off;
    blkptr_t bp;
    const unsigned char *nvlist;
    uint64_t val;
    uint64_t guid;
    uint64_t pool_txg, pool_guid;
    uint64_t is_log;
    const char *pool_name;
    const unsigned char *vdevs;
    const unsigned char *features;
    int i, rc, is_newer;
    char *upbuf;
    const struct uberblock *up;

    /*
     * Load the vdev label and figure out which
     * uberblock is most current.
     */
    memset(&vtmp, 0, sizeof(vtmp));
    vtmp.v_phys_read = phys_read;
    vtmp.v_read_priv = read_priv;
    off = offsetof(vdev_label_t, vl_vdev_phys);
    BP_ZERO(&bp);
    BP_SET_LSIZE(&bp, sizeof(vdev_phys_t));
    BP_SET_PSIZE(&bp, sizeof(vdev_phys_t));
    BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
    BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
    DVA_SET_OFFSET(BP_IDENTITY(&bp), off);
    ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
    if (vdev_read_phys(&vtmp, &bp, vdev_label, off, 0))
        return (EIO);

    if (vdev_label->vp_nvlist[0] != NV_ENCODE_XDR) {
        return (EIO);
    }

    nvlist = (const unsigned char *) vdev_label->vp_nvlist + 4;

    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_VERSION,
            DATA_TYPE_UINT64, 0, &val)) {
        return (EIO);
    }

    if (!SPA_VERSION_IS_SUPPORTED(val)) {
        printf("ZFS: unsupported ZFS version %u (should be %u)\n",
            (unsigned) val, (unsigned) SPA_VERSION);
        return (EIO);
    }

    /* Check ZFS features for read */
    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_FEATURES_FOR_READ,
            DATA_TYPE_NVLIST, 0, &features) == 0
        && nvlist_check_features_for_read(features) != 0)
        return (EIO);

    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_POOL_STATE,
            DATA_TYPE_UINT64, 0, &val)) {
        return (EIO);
    }

    if (val == POOL_STATE_DESTROYED) {
        /* We don't boot only from destroyed pools. */
        return (EIO);
    }

    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_POOL_TXG,
            DATA_TYPE_UINT64, 0, &pool_txg)
        || nvlist_find(nvlist,
               ZPOOL_CONFIG_POOL_GUID,
               DATA_TYPE_UINT64, 0, &pool_guid)
        || nvlist_find(nvlist,
               ZPOOL_CONFIG_POOL_NAME,
               DATA_TYPE_STRING, 0, &pool_name)) {
        /*
         * Cache and spare devices end up here - just ignore
         * them.
         */
        /*printf("ZFS: can't find pool details\n");*/
        return (EIO);
    }

    is_log = 0;
    (void) nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64, 0,
        &is_log);
    if (is_log)
        return (EIO);

    /*
     * Create the pool if this is the first time we've seen it.
     */
    spa = spa_find_by_guid(pool_guid);
    if (!spa) {
        spa = spa_create(pool_guid);
        spa->spa_name = strdup(pool_name);
    }
    if (pool_txg > spa->spa_txg) {
        spa->spa_txg = pool_txg;
        is_newer = 1;
    } else
        is_newer = 0;

    /*
     * Get the vdev tree and create our in-core copy of it.
     * If we already have a vdev with this guid, this must
     * be some kind of alias (overlapping slices, dangerously dedicated
     * disks etc).
     */
    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_GUID,
            DATA_TYPE_UINT64, 0, &guid)) {
        return (EIO);
    }
    vdev = vdev_find(guid);
    if (vdev && vdev->v_phys_read)  /* Has this vdev already been inited? */
        return (EIO);

    if (nvlist_find(nvlist,
            ZPOOL_CONFIG_VDEV_TREE,
            DATA_TYPE_NVLIST, 0, &vdevs)) {
        return (EIO);
    }

    rc = vdev_init_from_nvlist(vdevs, NULL, &top_vdev, is_newer);
    if (rc)
        return (rc);

    /*
     * Add the toplevel vdev to the pool if its not already there.
     */
    STAILQ_FOREACH(pool_vdev, &spa->spa_vdevs, v_childlink)
        if (top_vdev == pool_vdev)
            break;
    if (!pool_vdev && top_vdev)
        STAILQ_INSERT_TAIL(&spa->spa_vdevs, top_vdev, v_childlink);

    /*
     * We should already have created an incomplete vdev for this
     * vdev. Find it and initialise it with our read proc.
     */
    vdev = vdev_find(guid);
    if (vdev) {
        vdev->v_phys_read = phys_read;
        vdev->v_read_priv = read_priv;
        vdev->v_state = VDEV_STATE_HEALTHY;
    } else {
        printf("ZFS: inconsistent nvlist contents\n");
        return (EIO);
    }

    /*
     * Re-evaluate top-level vdev state.
     */
    vdev_set_state(top_vdev);

    /*
     * Ok, we are happy with the pool so far. Lets find
     * the best uberblock and then we can actually access
     * the contents of the pool.
     */
    upbuf = zfs_alloc(VDEV_UBERBLOCK_SIZE(vdev));
    up = (const struct uberblock *)upbuf;
    for (i = 0;
         i < VDEV_UBERBLOCK_COUNT(vdev);
         i++) {
        off = VDEV_UBERBLOCK_OFFSET(vdev, i);
        BP_ZERO(&bp);
        DVA_SET_OFFSET(&bp.blk_dva[0], off);
        BP_SET_LSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
        BP_SET_PSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
        BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
        BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
        ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);

        if (vdev_read_phys(vdev, &bp, upbuf, off, 0))
            continue;

        if (up->ub_magic != UBERBLOCK_MAGIC)
            continue;
        if (up->ub_txg < spa->spa_txg)
            continue;
        if (up->ub_txg > spa->spa_uberblock.ub_txg) {
            spa->spa_uberblock = *up;
        } else if (up->ub_txg == spa->spa_uberblock.ub_txg) {
            if (up->ub_timestamp > spa->spa_uberblock.ub_timestamp)
                spa->spa_uberblock = *up;
        }
    }
    zfs_free(upbuf, VDEV_UBERBLOCK_SIZE(vdev));

    if (spap)
        *spap = spa;
    return (0);
}

static int
ilog2(int n)
{
    int v;

    for (v = 0; v < 32; v++)
        if (n == (1 << v))
            return v;
    return -1;
}

static int
zio_read_gang(const spa_t *spa, const blkptr_t *bp, void *buf)
{
    blkptr_t gbh_bp;
    zio_gbh_phys_t zio_gb;
    char *pbuf;
    int i;

    /* Artificial BP for gang block header. */
    gbh_bp = *bp;
    BP_SET_PSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
    BP_SET_LSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
    BP_SET_CHECKSUM(&gbh_bp, ZIO_CHECKSUM_GANG_HEADER);
    BP_SET_COMPRESS(&gbh_bp, ZIO_COMPRESS_OFF);
    for (i = 0; i < SPA_DVAS_PER_BP; i++)
        DVA_SET_GANG(&gbh_bp.blk_dva[i], 0);

    /* Read gang header block using the artificial BP. */
    if (zio_read(spa, &gbh_bp, &zio_gb))
        return (EIO);

    pbuf = buf;
    for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
        blkptr_t *gbp = &zio_gb.zg_blkptr[i];

        if (BP_IS_HOLE(gbp))
            continue;
        if (zio_read(spa, gbp, pbuf))
            return (EIO);
        pbuf += BP_GET_PSIZE(gbp);
    }

    if (zio_checksum_verify(bp, buf))
        return (EIO);
    return (0);
}

static int
zio_read(const spa_t *spa, const blkptr_t *bp, void *buf)
{
    int cpfunc = BP_GET_COMPRESS(bp);
    uint64_t align, size;
    void *pbuf;
    int i, error;

    /*
     * Process data embedded in block pointer
     */
    if (BP_IS_EMBEDDED(bp)) {
        ASSERT(BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);

        size = BPE_GET_PSIZE(bp);
        ASSERT(size <= BPE_PAYLOAD_SIZE);

        if (cpfunc != ZIO_COMPRESS_OFF)
            pbuf = zfs_alloc(size);
        else
            pbuf = buf;

        decode_embedded_bp_compressed(bp, pbuf);
        error = 0;

        if (cpfunc != ZIO_COMPRESS_OFF) {
            error = zio_decompress_data(cpfunc, pbuf,
                size, buf, BP_GET_LSIZE(bp));
            zfs_free(pbuf, size);
        }
        if (error != 0)
            printf("ZFS: i/o error - unable to decompress block pointer data, error %d\n",
                error);
        return (error);
    }

    error = EIO;

    for (i = 0; i < SPA_DVAS_PER_BP; i++) {
        const dva_t *dva = &bp->blk_dva[i];
        vdev_t *vdev;
        int vdevid;
        off_t offset;

        if (!dva->dva_word[0] && !dva->dva_word[1])
            continue;

        vdevid = DVA_GET_VDEV(dva);
        offset = DVA_GET_OFFSET(dva);
        STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
            if (vdev->v_id == vdevid)
                break;
        }
        if (!vdev || !vdev->v_read)
            continue;

        size = BP_GET_PSIZE(bp);
        if (vdev->v_read == vdev_raidz_read) {
            align = 1ULL << vdev->v_top->v_ashift;
            if (P2PHASE(size, align) != 0)
                size = P2ROUNDUP(size, align);
        }
        if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
            pbuf = zfs_alloc(size);
        else
            pbuf = buf;

        if (DVA_GET_GANG(dva))
            error = zio_read_gang(spa, bp, pbuf);
        else
            error = vdev->v_read(vdev, bp, pbuf, offset, size);
        if (error == 0) {
            if (cpfunc != ZIO_COMPRESS_OFF)
                error = zio_decompress_data(cpfunc, pbuf,
                    BP_GET_PSIZE(bp), buf, BP_GET_LSIZE(bp));
            else if (size != BP_GET_PSIZE(bp))
                bcopy(pbuf, buf, BP_GET_PSIZE(bp));
        }
        if (buf != pbuf)
            zfs_free(pbuf, size);
        if (error == 0)
            break;
    }
    if (error != 0)
        printf("ZFS: i/o error - all block copies unavailable\n");
    return (error);
}

static int
dnode_read(const spa_t *spa, const dnode_phys_t *dnode, off_t offset, void *buf, size_t buflen)
{
    int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
    int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
    int nlevels = dnode->dn_nlevels;
    int i, rc;

    if (bsize > SPA_MAXBLOCKSIZE) {
        printf("ZFS: I/O error - blocks larger than %llu are not "
            "supported\n", SPA_MAXBLOCKSIZE);
        return (EIO);
    }

    /*
     * Note: bsize may not be a power of two here so we need to do an
     * actual divide rather than a bitshift.
     */
    while (buflen > 0) {
        uint64_t bn = offset / bsize;
        int boff = offset % bsize;
        int ibn;
        const blkptr_t *indbp;
        blkptr_t bp;

        if (bn > dnode->dn_maxblkid) {
            printf("warning: zfs bug: bn %llx > dn_maxblkid %llx\n",
                (unsigned long long)bn,
                (unsigned long long)dnode->dn_maxblkid);
            /*
             * zfs bug, will not return error
             * return (EIO);
             */
        }

        if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
            goto cached;

        indbp = dnode->dn_blkptr;
        for (i = 0; i < nlevels; i++) {
            /*
             * Copy the bp from the indirect array so that
             * we can re-use the scratch buffer for multi-level
             * objects.
             */
            ibn = bn >> ((nlevels - i - 1) * ibshift);
            ibn &= ((1 << ibshift) - 1);
            bp = indbp[ibn];
            if (BP_IS_HOLE(&bp)) {
                memset(dnode_cache_buf, 0, bsize);
                break;
            }
            rc = zio_read(spa, &bp, dnode_cache_buf);
            if (rc)
                return (rc);
            indbp = (const blkptr_t *) dnode_cache_buf;
        }
        dnode_cache_obj = dnode;
        dnode_cache_bn = bn;
    cached:

        /*
         * The buffer contains our data block. Copy what we
         * need from it and loop.
         */
        i = bsize - boff;
        if (i > buflen) i = buflen;
        memcpy(buf, &dnode_cache_buf[boff], i);
        buf = ((char*) buf) + i;
        offset += i;
        buflen -= i;
    }

    return (0);
}

/*
 * Lookup a value in a microzap directory. Assumes that the zap
 * scratch buffer contains the directory contents.
 */
static int
mzap_lookup(const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
    const mzap_phys_t *mz;
    const mzap_ent_phys_t *mze;
    size_t size;
    int chunks, i;

    /*
     * Microzap objects use exactly one block. Read the whole
     * thing.
     */
    size = dnode->dn_datablkszsec * 512;

    mz = (const mzap_phys_t *) zap_scratch;
    chunks = size / MZAP_ENT_LEN - 1;

    for (i = 0; i < chunks; i++) {
        mze = &mz->mz_chunk[i];
        if (!strcmp(mze->mze_name, name)) {
            *value = mze->mze_value;
            return (0);
        }
    }

    return (ENOENT);
}

/*
 * Compare a name with a zap leaf entry. Return non-zero if the name
 * matches.
 */
static int
fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, const char *name)
{
    size_t namelen;
    const zap_leaf_chunk_t *nc;
    const char *p;

    namelen = zc->l_entry.le_name_numints;

    nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
    p = name;
    while (namelen > 0) {
        size_t len;
        len = namelen;
        if (len > ZAP_LEAF_ARRAY_BYTES)
            len = ZAP_LEAF_ARRAY_BYTES;
        if (memcmp(p, nc->l_array.la_array, len))
            return (0);
        p += len;
        namelen -= len;
        nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
    }

    return 1;
}

/*
 * Extract a uint64_t value from a zap leaf entry.
 */
static uint64_t
fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
{
    const zap_leaf_chunk_t *vc;
    int i;
    uint64_t value;
    const uint8_t *p;

    vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
    for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
        value = (value << 8) | p[i];
    }

    return value;
}

/*
 * Lookup a value in a fatzap directory. Assumes that the zap scratch
 * buffer contains the directory header.
 */
static int
fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
    int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
    zap_phys_t zh = *(zap_phys_t *) zap_scratch;
    fat_zap_t z;
    uint64_t *ptrtbl;
    uint64_t hash;
    int rc;

    if (zh.zap_magic != ZAP_MAGIC)
        return (EIO);

    z.zap_block_shift = ilog2(bsize);
    z.zap_phys = (zap_phys_t *) zap_scratch;

    /*
     * Figure out where the pointer table is and read it in if necessary.
     */
    if (zh.zap_ptrtbl.zt_blk) {
        rc = dnode_read(spa, dnode, zh.zap_ptrtbl.zt_blk * bsize,
                   zap_scratch, bsize);
        if (rc)
            return (rc);
        ptrtbl = (uint64_t *) zap_scratch;
    } else {
        ptrtbl = &ZAP_EMBEDDED_PTRTBL_ENT(&z, 0);
    }

    hash = zap_hash(zh.zap_salt, name);

    zap_leaf_t zl;
    zl.l_bs = z.zap_block_shift;

    off_t off = ptrtbl[hash >> (64 - zh.zap_ptrtbl.zt_shift)] << zl.l_bs;
    zap_leaf_chunk_t *zc;

    rc = dnode_read(spa, dnode, off, zap_scratch, bsize);
    if (rc)
        return (rc);

    zl.l_phys = (zap_leaf_phys_t *) zap_scratch;

    /*
     * Make sure this chunk matches our hash.
     */
    if (zl.l_phys->l_hdr.lh_prefix_len > 0
        && zl.l_phys->l_hdr.lh_prefix
        != hash >> (64 - zl.l_phys->l_hdr.lh_prefix_len))
        return (ENOENT);

    /*
     * Hash within the chunk to find our entry.
     */
    int shift = (64 - ZAP_LEAF_HASH_SHIFT(&zl) - zl.l_phys->l_hdr.lh_prefix_len);
    int h = (hash >> shift) & ((1 << ZAP_LEAF_HASH_SHIFT(&zl)) - 1);
    h = zl.l_phys->l_hash[h];
    if (h == 0xffff)
        return (ENOENT);
    zc = &ZAP_LEAF_CHUNK(&zl, h);
    while (zc->l_entry.le_hash != hash) {
        if (zc->l_entry.le_next == 0xffff) {
            zc = 0;
            break;
        }
        zc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_next);
    }
    if (fzap_name_equal(&zl, zc, name)) {
        if (zc->l_entry.le_value_intlen * zc->l_entry.le_value_numints > 8)
            return (E2BIG);
        *value = fzap_leaf_value(&zl, zc);
        return (0);
    }

    return (ENOENT);
}

/*
 * Lookup a name in a zap object and return its value as a uint64_t.
 */
static int
zap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
    int rc;
    uint64_t zap_type;
    size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;

    rc = dnode_read(spa, dnode, 0, zap_scratch, size);
    if (rc)
        return (rc);

    zap_type = *(uint64_t *) zap_scratch;
    if (zap_type == ZBT_MICRO)
        return mzap_lookup(dnode, name, value);
    else if (zap_type == ZBT_HEADER)
        return fzap_lookup(spa, dnode, name, value);
    printf("ZFS: invalid zap_type=%d\n", (int)zap_type);
    return (EIO);
}

/*
 * List a microzap directory. Assumes that the zap scratch buffer contains
 * the directory contents.
 */
static int
mzap_list(const dnode_phys_t *dnode, int (*callback)(const char *, uint64_t))
{
    const mzap_phys_t *mz;
    const mzap_ent_phys_t *mze;
    size_t size;
    int chunks, i, rc;

    /*
     * Microzap objects use exactly one block. Read the whole
     * thing.
     */
    size = dnode->dn_datablkszsec * 512;
    mz = (const mzap_phys_t *) zap_scratch;
    chunks = size / MZAP_ENT_LEN - 1;

    for (i = 0; i < chunks; i++) {
        mze = &mz->mz_chunk[i];
        if (mze->mze_name[0]) {
            rc = callback(mze->mze_name, mze->mze_value);
            if (rc != 0)
                return (rc);
        }
    }

    return (0);
}

/*
 * List a fatzap directory. Assumes that the zap scratch buffer contains
 * the directory header.
 */
static int
fzap_list(const spa_t *spa, const dnode_phys_t *dnode, int (*callback)(const char *, uint64_t))
{
    int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
    zap_phys_t zh = *(zap_phys_t *) zap_scratch;
    fat_zap_t z;
    int i, j, rc;

    if (zh.zap_magic != ZAP_MAGIC)
        return (EIO);

    z.zap_block_shift = ilog2(bsize);
    z.zap_phys = (zap_phys_t *) zap_scratch;

    /*
     * This assumes that the leaf blocks start at block 1. The
     * documentation isn't exactly clear on this.
     */
    zap_leaf_t zl;
    zl.l_bs = z.zap_block_shift;
    for (i = 0; i < zh.zap_num_leafs; i++) {
        off_t off = (i + 1) << zl.l_bs;
        char name[256], *p;
        uint64_t value;

        if (dnode_read(spa, dnode, off, zap_scratch, bsize))
            return (EIO);

        zl.l_phys = (zap_leaf_phys_t *) zap_scratch;

        for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
            zap_leaf_chunk_t *zc, *nc;
            int namelen;

            zc = &ZAP_LEAF_CHUNK(&zl, j);
            if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
                continue;
            namelen = zc->l_entry.le_name_numints;
            if (namelen > sizeof(name))
                namelen = sizeof(name);

            /*
             * Paste the name back together.
             */
            nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
            p = name;
            while (namelen > 0) {
                int len;
                len = namelen;
                if (len > ZAP_LEAF_ARRAY_BYTES)
                    len = ZAP_LEAF_ARRAY_BYTES;
                memcpy(p, nc->l_array.la_array, len);
                p += len;
                namelen -= len;
                nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
            }

            /*
             * Assume the first eight bytes of the value are
             * a uint64_t.
             */
            value = fzap_leaf_value(&zl, zc);

            //printf("%s 0x%jx\n", name, (uintmax_t)value);
            rc = callback((const char *)name, value);
            if (rc != 0)
                return (rc);
        }
    }

    return (0);
}

static int zfs_printf(const char *name, uint64_t value __unused)
{

    printf("%s\n", name);

    return (0);
}

/*
 * List a zap directory.
 */
static int
zap_list(const spa_t *spa, const dnode_phys_t *dnode)
{
    uint64_t zap_type;
    size_t size = dnode->dn_datablkszsec * 512;

    if (dnode_read(spa, dnode, 0, zap_scratch, size))
        return (EIO);

    zap_type = *(uint64_t *) zap_scratch;
    if (zap_type == ZBT_MICRO)
        return mzap_list(dnode, zfs_printf);
    else
        return fzap_list(spa, dnode, zfs_printf);
}

static int
objset_get_dnode(const spa_t *spa, const objset_phys_t *os, uint64_t objnum, dnode_phys_t *dnode)
{
    off_t offset;

    offset = objnum * sizeof(dnode_phys_t);
    return dnode_read(spa, &os->os_meta_dnode, offset,
        dnode, sizeof(dnode_phys_t));
}

static int
mzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
{
    const mzap_phys_t *mz;
    const mzap_ent_phys_t *mze;
    size_t size;
    int chunks, i;

    /*
     * Microzap objects use exactly one block. Read the whole
     * thing.
     */
    size = dnode->dn_datablkszsec * 512;

    mz = (const mzap_phys_t *) zap_scratch;
    chunks = size / MZAP_ENT_LEN - 1;

    for (i = 0; i < chunks; i++) {
        mze = &mz->mz_chunk[i];
        if (value == mze->mze_value) {
            strcpy(name, mze->mze_name);
            return (0);
        }
    }

    return (ENOENT);
}

static void
fzap_name_copy(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, char *name)
{
    size_t namelen;
    const zap_leaf_chunk_t *nc;
    char *p;

    namelen = zc->l_entry.le_name_numints;

    nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
    p = name;
    while (namelen > 0) {
        size_t len;
        len = namelen;
        if (len > ZAP_LEAF_ARRAY_BYTES)
            len = ZAP_LEAF_ARRAY_BYTES;
        memcpy(p, nc->l_array.la_array, len);
        p += len;
        namelen -= len;
        nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
    }

    *p = '\0';
}

static int
fzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
{
    int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
    zap_phys_t zh = *(zap_phys_t *) zap_scratch;
    fat_zap_t z;
    int i, j;

    if (zh.zap_magic != ZAP_MAGIC)
        return (EIO);

    z.zap_block_shift = ilog2(bsize);
    z.zap_phys = (zap_phys_t *) zap_scratch;

    /*
     * This assumes that the leaf blocks start at block 1. The
     * documentation isn't exactly clear on this.
     */
    zap_leaf_t zl;
    zl.l_bs = z.zap_block_shift;
    for (i = 0; i < zh.zap_num_leafs; i++) {
        off_t off = (i + 1) << zl.l_bs;

        if (dnode_read(spa, dnode, off, zap_scratch, bsize))
            return (EIO);

        zl.l_phys = (zap_leaf_phys_t *) zap_scratch;

        for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
            zap_leaf_chunk_t *zc;

            zc = &ZAP_LEAF_CHUNK(&zl, j);
            if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
                continue;
            if (zc->l_entry.le_value_intlen != 8 ||
                zc->l_entry.le_value_numints != 1)
                continue;

            if (fzap_leaf_value(&zl, zc) == value) {
                fzap_name_copy(&zl, zc, name);
                return (0);
            }
        }
    }

    return (ENOENT);
}

static int
zap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
{
    int rc;
    uint64_t zap_type;
    size_t size = dnode->dn_datablkszsec * 512;

    rc = dnode_read(spa, dnode, 0, zap_scratch, size);
    if (rc)
        return (rc);

    zap_type = *(uint64_t *) zap_scratch;
    if (zap_type == ZBT_MICRO)
        return mzap_rlookup(spa, dnode, name, value);
    else
        return fzap_rlookup(spa, dnode, name, value);
}

static int
zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
{
    char name[256];
    char component[256];
    uint64_t dir_obj, parent_obj, child_dir_zapobj;
    dnode_phys_t child_dir_zap, dataset, dir, parent;
    dsl_dir_phys_t *dd;
    dsl_dataset_phys_t *ds;
    char *p;
    int len;

    p = &name[sizeof(name) - 1];
    *p = '\0';

    if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
        printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
        return (EIO);
    }
    ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
    dir_obj = ds->ds_dir_obj;

    for (;;) {
        if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir) != 0)
            return (EIO);
        dd = (dsl_dir_phys_t *)&dir.dn_bonus;

        /* Actual loop condition. */
        parent_obj  = dd->dd_parent_obj;
        if (parent_obj == 0)
            break;

        if (objset_get_dnode(spa, &spa->spa_mos, parent_obj, &parent) != 0)
            return (EIO);
        dd = (dsl_dir_phys_t *)&parent.dn_bonus;
        child_dir_zapobj = dd->dd_child_dir_zapobj;
        if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
            return (EIO);
        if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
            return (EIO);

        len = strlen(component);
        p -= len;
        memcpy(p, component, len);
        --p;
        *p = '/';

        /* Actual loop iteration. */
        dir_obj = parent_obj;
    }

    if (*p != '\0')
        ++p;
    strcpy(result, p);

    return (0);
}

static int
zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
{
    char element[256];
    uint64_t dir_obj, child_dir_zapobj;
    dnode_phys_t child_dir_zap, dir;
    dsl_dir_phys_t *dd;
    const char *p, *q;

    if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir))
        return (EIO);
    if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, &dir_obj))
        return (EIO);

    p = name;
    for (;;) {
        if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir))
            return (EIO);
        dd = (dsl_dir_phys_t *)&dir.dn_bonus;

        while (*p == '/')
            p++;
        /* Actual loop condition #1. */
        if (*p == '\0')
            break;

        q = strchr(p, '/');
        if (q) {
            memcpy(element, p, q - p);
            element[q - p] = '\0';
            p = q + 1;
        } else {
            strcpy(element, p);
            p += strlen(p);
        }

        child_dir_zapobj = dd->dd_child_dir_zapobj;
        if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
            return (EIO);

        /* Actual loop condition #2. */
        if (zap_lookup(spa, &child_dir_zap, element, &dir_obj) != 0)
            return (ENOENT);
    }

    *objnum = dd->dd_head_dataset_obj;
    return (0);
}

#pragma GCC diagnostic ignored "-Wstrict-aliasing"
static int
zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
{
    uint64_t dir_obj, child_dir_zapobj;
    dnode_phys_t child_dir_zap, dir, dataset;
    dsl_dataset_phys_t *ds;
    dsl_dir_phys_t *dd;

    if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
        printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
        return (EIO);
    }
    ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
    dir_obj = ds->ds_dir_obj;

    if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir)) {
        printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
        return (EIO);
    }
    dd = (dsl_dir_phys_t *)&dir.dn_bonus;

    child_dir_zapobj = dd->dd_child_dir_zapobj;
    if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0) {
        printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
        return (EIO);
    }

    return (zap_list(spa, &child_dir_zap) != 0);
}

int
zfs_callback_dataset(const spa_t *spa, uint64_t objnum, int (*callback)(const char *, uint64_t))
{
    uint64_t dir_obj, child_dir_zapobj, zap_type;
    dnode_phys_t child_dir_zap, dir, dataset;
    dsl_dataset_phys_t *ds;
    dsl_dir_phys_t *dd;
    int err;

    err = objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset);
    if (err != 0) {
        printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
        return (err);
    }
    ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
    dir_obj = ds->ds_dir_obj;

    err = objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir);
    if (err != 0) {
        printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
        return (err);
    }
    dd = (dsl_dir_phys_t *)&dir.dn_bonus;

    child_dir_zapobj = dd->dd_child_dir_zapobj;
    err = objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap);
    if (err != 0) {
        printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
        return (err);
    }

    err = dnode_read(spa, &child_dir_zap, 0, zap_scratch, child_dir_zap.dn_datablkszsec * 512);
    if (err != 0)
        return (err);

    zap_type = *(uint64_t *) zap_scratch;
    if (zap_type == ZBT_MICRO)
        return mzap_list(&child_dir_zap, callback);
    else
        return fzap_list(spa, &child_dir_zap, callback);
}

/*
 * Find the object set given the object number of its dataset object
 * and return its details in *objset
 */
static int
zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
{
    dnode_phys_t dataset;
    dsl_dataset_phys_t *ds;

    if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
        printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
        return (EIO);
    }

    ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
    if (zio_read(spa, &ds->ds_bp, objset)) {
        printf("ZFS: can't read object set for dataset %ju\n",
            (uintmax_t)objnum);
        return (EIO);
    }

    return (0);
}

/*
 * Find the object set pointed to by the BOOTFS property or the root
 * dataset if there is none and return its details in *objset
 */
static int
zfs_get_root(const spa_t *spa, uint64_t *objid)
{
    dnode_phys_t dir, propdir;
    uint64_t props, bootfs, root;

    *objid = 0;

    /*
     * Start with the MOS directory object.
     */
    if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir)) {
        printf("ZFS: can't read MOS object directory\n");
        return (EIO);
    }

    /*
     * Lookup the pool_props and see if we can find a bootfs.
     */
    if (zap_lookup(spa, &dir, DMU_POOL_PROPS, &props) == 0
         && objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0
         && zap_lookup(spa, &propdir, "bootfs", &bootfs) == 0
         && bootfs != 0)
    {
        *objid = bootfs;
        return (0);
    }
    /*
     * Lookup the root dataset directory
     */
    if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, &root)
        || objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
        printf("ZFS: can't find root dsl_dir\n");
        return (EIO);
    }

    /*
     * Use the information from the dataset directory's bonus buffer
     * to find the dataset object and from that the object set itself.
     */
    dsl_dir_phys_t *dd = (dsl_dir_phys_t *) &dir.dn_bonus;
    *objid = dd->dd_head_dataset_obj;
    return (0);
}

static int
zfs_mount(const spa_t *spa, uint64_t rootobj, struct zfsmount *mnt)
{

    mnt->spa = spa;

    /*
     * Find the root object set if not explicitly provided
     */
    if (rootobj == 0 && zfs_get_root(spa, &rootobj)) {
        printf("ZFS: can't find root filesystem\n");
        return (EIO);
    }

    if (zfs_mount_dataset(spa, rootobj, &mnt->objset)) {
        printf("ZFS: can't open root filesystem\n");
        return (EIO);
    }

    mnt->rootobj = rootobj;

    return (0);
}

/*
 * callback function for feature name checks.
 */
static int
check_feature(const char *name, uint64_t value)
{
    int i;

    if (value == 0)
        return (0);
    if (name[0] == '\0')
        return (0);

    for (i = 0; features_for_read[i] != NULL; i++) {
        if (strcmp(name, features_for_read[i]) == 0)
            return (0);
    }
    printf("ZFS: unsupported feature: %s\n", name);
    return (EIO);
}

/*
 * Checks whether the MOS features that are active are supported.
 */
static int
check_mos_features(const spa_t *spa)
{
    dnode_phys_t dir;
    uint64_t objnum, zap_type;
    size_t size;
    int rc;

    if ((rc = objset_get_dnode(spa, &spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
        &dir)) != 0)
        return (rc);
    if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ, &objnum)) != 0)
        return (rc);

    if ((rc = objset_get_dnode(spa, &spa->spa_mos, objnum, &dir)) != 0)
        return (rc);

    if (dir.dn_type != DMU_OTN_ZAP_METADATA)
        return (EIO);

    size = dir.dn_datablkszsec * 512;
    if (dnode_read(spa, &dir, 0, zap_scratch, size))
        return (EIO);

    zap_type = *(uint64_t *) zap_scratch;
    if (zap_type == ZBT_MICRO)
        rc = mzap_list(&dir, check_feature);
    else
        rc = fzap_list(spa, &dir, check_feature);

    return (rc);
}

static int
zfs_spa_init(spa_t *spa)
{
    int rc;

    if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
        printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
        return (EIO);
    }
    if (spa->spa_mos.os_type != DMU_OST_META) {
        printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
        return (EIO);
    }

    rc = check_mos_features(spa);
    if (rc != 0) {
        printf("ZFS: pool %s is not supported\n", spa->spa_name);
    }

    return (rc);
}

static int
zfs_dnode_stat(const spa_t *spa, dnode_phys_t *dn, struct stat *sb)
{

    if (dn->dn_bonustype != DMU_OT_SA) {
        znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;

        sb->st_mode = zp->zp_mode;
        sb->st_uid = zp->zp_uid;
        sb->st_gid = zp->zp_gid;
        sb->st_size = zp->zp_size;
    } else {
        sa_hdr_phys_t *sahdrp;
        int hdrsize;
        size_t size = 0;
        void *buf = NULL;

        if (dn->dn_bonuslen != 0)
            sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
        else {
            if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
                blkptr_t *bp = &dn->dn_spill;
                int error;

                size = BP_GET_LSIZE(bp);
                buf = zfs_alloc(size);
                error = zio_read(spa, bp, buf);
                if (error != 0) {
                    zfs_free(buf, size);
                    return (error);
                }
                sahdrp = buf;
            } else {
                return (EIO);
            }
        }
        hdrsize = SA_HDR_SIZE(sahdrp);
        sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
            SA_MODE_OFFSET);
        sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
            SA_UID_OFFSET);
        sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
            SA_GID_OFFSET);
        sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
            SA_SIZE_OFFSET);
        if (buf != NULL)
            zfs_free(buf, size);
    }

    return (0);
}

/*
 * Lookup a file and return its dnode.
 */
static int
zfs_lookup(const struct zfsmount *mnt, const char *upath, dnode_phys_t *dnode)
{
    int rc;
    uint64_t objnum, rootnum, parentnum;
    const spa_t *spa;
    dnode_phys_t dn;
    const char *p, *q;
    char element[256];
    char path[1024];
    int symlinks_followed = 0;
    struct stat sb;

    spa = mnt->spa;
    if (mnt->objset.os_type != DMU_OST_ZFS) {
        printf("ZFS: unexpected object set type %ju\n",
            (uintmax_t)mnt->objset.os_type);
        return (EIO);
    }

    /*
     * Get the root directory dnode.
     */
    rc = objset_get_dnode(spa, &mnt->objset, MASTER_NODE_OBJ, &dn);
    if (rc)
        return (rc);

    rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, &rootnum);
    if (rc)
        return (rc);

    rc = objset_get_dnode(spa, &mnt->objset, rootnum, &dn);
    if (rc)
        return (rc);

    objnum = rootnum;
    p = upath;
    while (p && *p) {
        while (*p == '/')
            p++;
        if (!*p)
            break;
        q = strchr(p, '/');
        if (q) {
            memcpy(element, p, q - p);
            element[q - p] = 0;
            p = q;
        } else {
            strcpy(element, p);
            p = 0;
        }

        rc = zfs_dnode_stat(spa, &dn, &sb);
        if (rc)
            return (rc);
        if (!S_ISDIR(sb.st_mode))
            return (ENOTDIR);

        parentnum = objnum;
        rc = zap_lookup(spa, &dn, element, &objnum);
        if (rc)
            return (rc);
        objnum = ZFS_DIRENT_OBJ(objnum);

        rc = objset_get_dnode(spa, &mnt->objset, objnum, &dn);
        if (rc)
            return (rc);

        /*
         * Check for symlink.
         */
        rc = zfs_dnode_stat(spa, &dn, &sb);
        if (rc)
            return (rc);
        if (S_ISLNK(sb.st_mode)) {
            if (symlinks_followed > 10)
                return (EMLINK);
            symlinks_followed++;

            /*
             * Read the link value and copy the tail of our
             * current path onto the end.
             */
            if (p)
                strcpy(&path[sb.st_size], p);
            else
                path[sb.st_size] = 0;
            /*
             * Second test is purely to silence bogus compiler
             * warning about accessing past the end of dn_bonus.
             */
            if (sb.st_size + sizeof(znode_phys_t) <=
                dn.dn_bonuslen && sizeof(znode_phys_t) <=
                sizeof(dn.dn_bonus)) {
                memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
                    sb.st_size);
            } else {
                rc = dnode_read(spa, &dn, 0, path, sb.st_size);
                if (rc)
                    return (rc);
            }

            /*
             * Restart with the new path, starting either at
             * the root or at the parent depending whether or
             * not the link is relative.
             */
            p = path;
            if (*p == '/')
                objnum = rootnum;
            else
                objnum = parentnum;
            objset_get_dnode(spa, &mnt->objset, objnum, &dn);
        }
    }

    *dnode = dn;
    return (0);
}