cmd/zpool/zpool_vdev.c

	zpool_vdev.c revision 1195e687f1c03c8d57417b5999578922e20a3554
/*
 * 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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Functions to convert between a list of vdevs and an nvlist representing the
 * configuration.  Each entry in the list can be one of:
 *
 *  Device vdevs
 *      disk=(path=..., devid=...)
 *      file=(path=...)
 *
 *  Group vdevs
 *      raidz[1|2]=(...)
 *      mirror=(...)
 *
 *  Hot spares
 *
 * While the underlying implementation supports it, group vdevs cannot contain
 * other group vdevs.  All userland verification of devices is contained within
 * this file.  If successful, the nvlist returned can be passed directly to the
 * kernel; we've done as much verification as possible in userland.
 *
 * Hot spares are a special case, and passed down as an array of disk vdevs, at
 * the same level as the root of the vdev tree.
 *
 * The only function exported by this file is 'make_root_vdev'.  The
 * function performs several passes:
 *
 *  1. Construct the vdev specification.  Performs syntax validation and
 *         makes sure each device is valid.
 *  2. Check for devices in use.  Using libdiskmgt, makes sure that no
 *         devices are also in use.  Some can be overridden using the 'force'
 *         flag, others cannot.
 *  3. Check for replication errors if the 'force' flag is not specified.
 *         validates that the replication level is consistent across the
 *         entire pool.
 *  4. Call libzfs to label any whole disks with an EFI label.
 */

#include <assert.h>
#include <devid.h>
#include <errno.h>
#include <fcntl.h>
#include <libdiskmgt.h>
#include <libintl.h>
#include <libnvpair.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/efi_partition.h>
#include <sys/stat.h>
#include <sys/vtoc.h>
#include <sys/mntent.h>

#include "zpool_util.h"

#define DISK_ROOT   "/dev/dsk"
#define RDISK_ROOT  "/dev/rdsk"
#define BACKUP_SLICE    "s2"

/*
 * For any given vdev specification, we can have multiple errors.  The
 * vdev_error() function keeps track of whether we have seen an error yet, and
 * prints out a header if its the first error we've seen.
 */
boolean_t error_seen;
boolean_t is_force;

/*PRINTFLIKE1*/
static void
vdev_error(const char *fmt, ...)
{
    va_list ap;

    if (!error_seen) {
        (void) fprintf(stderr, gettext("invalid vdev specification\n"));
        if (!is_force)
            (void) fprintf(stderr, gettext("use '-f' to override "
                "the following errors:\n"));
        else
            (void) fprintf(stderr, gettext("the following errors "
                "must be manually repaired:\n"));
        error_seen = B_TRUE;
    }

    va_start(ap, fmt);
    (void) vfprintf(stderr, fmt, ap);
    va_end(ap);
}

static void
libdiskmgt_error(int error)
{
    /*
     * ENXIO/ENODEV is a valid error message if the device doesn't live in
     * /dev/dsk.  Don't bother printing an error message in this case.
     */
    if (error == ENXIO || error == ENODEV)
        return;

    (void) fprintf(stderr, gettext("warning: device in use checking "
        "failed: %s\n"), strerror(error));
}

/*
 * Validate a device, passing the bulk of the work off to libdiskmgt.
 */
static int
check_slice(const char *path, int force, boolean_t wholedisk, boolean_t isspare)
{
    char *msg;
    int error = 0;
    dm_who_type_t who;

    if (force)
        who = DM_WHO_ZPOOL_FORCE;
    else if (isspare)
        who = DM_WHO_ZPOOL_SPARE;
    else
        who = DM_WHO_ZPOOL;

    if (dm_inuse((char *)path, &msg, who, &error) || error) {
        if (error != 0) {
            libdiskmgt_error(error);
            return (0);
        } else {
            vdev_error("%s", msg);
            free(msg);
            return (-1);
        }
    }

    /*
     * If we're given a whole disk, ignore overlapping slices since we're
     * about to label it anyway.
     */
    error = 0;
    if (!wholedisk && !force &&
        (dm_isoverlapping((char *)path, &msg, &error) || error)) {
        if (error == 0) {
            /* dm_isoverlapping returned -1 */
            vdev_error(gettext("%s overlaps with %s\n"), path, msg);
            free(msg);
            return (-1);
        } else if (error != ENODEV) {
            /* libdiskmgt's devcache only handles physical drives */
            libdiskmgt_error(error);
            return (0);
        }
    }

    return (0);
}


/*
 * Validate a whole disk.  Iterate over all slices on the disk and make sure
 * that none is in use by calling check_slice().
 */
static int
check_disk(const char *name, dm_descriptor_t disk, int force, int isspare)
{
    dm_descriptor_t *drive, *media, *slice;
    int err = 0;
    int i;
    int ret;

    /*
     * Get the drive associated with this disk.  This should never fail,
     * because we already have an alias handle open for the device.
     */
    if ((drive = dm_get_associated_descriptors(disk, DM_DRIVE,
        &err)) == NULL || *drive == NULL) {
        if (err)
            libdiskmgt_error(err);
        return (0);
    }

    if ((media = dm_get_associated_descriptors(*drive, DM_MEDIA,
        &err)) == NULL) {
        dm_free_descriptors(drive);
        if (err)
            libdiskmgt_error(err);
        return (0);
    }

    dm_free_descriptors(drive);

    /*
     * It is possible that the user has specified a removable media drive,
     * and the media is not present.
     */
    if (*media == NULL) {
        dm_free_descriptors(media);
        vdev_error(gettext("'%s' has no media in drive\n"), name);
        return (-1);
    }

    if ((slice = dm_get_associated_descriptors(*media, DM_SLICE,
        &err)) == NULL) {
        dm_free_descriptors(media);
        if (err)
            libdiskmgt_error(err);
        return (0);
    }

    dm_free_descriptors(media);

    ret = 0;

    /*
     * Iterate over all slices and report any errors.  We don't care about
     * overlapping slices because we are using the whole disk.
     */
    for (i = 0; slice[i] != NULL; i++) {
        char *name = dm_get_name(slice[i], &err);

        if (check_slice(name, force, B_TRUE, isspare) != 0)
            ret = -1;

        dm_free_name(name);
    }

    dm_free_descriptors(slice);
    return (ret);
}

/*
 * Validate a device.
 */
static int
check_device(const char *path, boolean_t force, boolean_t isspare)
{
    dm_descriptor_t desc;
    int err;
    char *dev;

    /*
     * For whole disks, libdiskmgt does not include the leading dev path.
     */
    dev = strrchr(path, '/');
    assert(dev != NULL);
    dev++;
    if ((desc = dm_get_descriptor_by_name(DM_ALIAS, dev, &err)) != NULL) {
        err = check_disk(path, desc, force, isspare);
        dm_free_descriptor(desc);
        return (err);
    }

    return (check_slice(path, force, B_FALSE, isspare));
}

/*
 * Check that a file is valid.  All we can do in this case is check that it's
 * not in use by another pool, and not in use by swap.
 */
static int
check_file(const char *file, boolean_t force, boolean_t isspare)
{
    char  *name;
    int fd;
    int ret = 0;
    int err;
    pool_state_t state;
    boolean_t inuse;

    if (dm_inuse_swap(file, &err)) {
        if (err)
            libdiskmgt_error(err);
        else
            vdev_error(gettext("%s is currently used by swap. "
                "Please see swap(1M).\n"), file);
        return (-1);
    }

    if ((fd = open(file, O_RDONLY)) < 0)
        return (0);

    if (zpool_in_use(g_zfs, fd, &state, &name, &inuse) == 0 && inuse) {
        const char *desc;

        switch (state) {
        case POOL_STATE_ACTIVE:
            desc = gettext("active");
            break;

        case POOL_STATE_EXPORTED:
            desc = gettext("exported");
            break;

        case POOL_STATE_POTENTIALLY_ACTIVE:
            desc = gettext("potentially active");
            break;

        default:
            desc = gettext("unknown");
            break;
        }

        /*
         * Allow hot spares to be shared between pools.
         */
        if (state == POOL_STATE_SPARE && isspare)
            return (0);

        if (state == POOL_STATE_ACTIVE ||
            state == POOL_STATE_SPARE || !force) {
            switch (state) {
            case POOL_STATE_SPARE:
                vdev_error(gettext("%s is reserved as a hot "
                    "spare for pool %s\n"), file, name);
                break;
            default:
                vdev_error(gettext("%s is part of %s pool "
                    "'%s'\n"), file, desc, name);
                break;
            }
            ret = -1;
        }

        free(name);
    }

    (void) close(fd);
    return (ret);
}


/*
 * By "whole disk" we mean an entire physical disk (something we can
 * label, toggle the write cache on, etc.) as opposed to the full
 * capacity of a pseudo-device such as lofi or did.  We act as if we
 * are labeling the disk, which should be a pretty good test of whether
 * it's a viable device or not.  Returns B_TRUE if it is and B_FALSE if
 * it isn't.
 */
static boolean_t
is_whole_disk(const char *arg)
{
    struct dk_gpt *label;
    int fd;
    char    path[MAXPATHLEN];

    (void) snprintf(path, sizeof (path), "%s%s%s",
        RDISK_ROOT, strrchr(arg, '/'), BACKUP_SLICE);
    if ((fd = open(path, O_RDWR | O_NDELAY)) < 0)
        return (B_FALSE);
    if (efi_alloc_and_init(fd, EFI_NUMPAR, &label) != 0) {
        (void) close(fd);
        return (B_FALSE);
    }
    efi_free(label);
    (void) close(fd);
    return (B_TRUE);
}

/*
 * Create a leaf vdev.  Determine if this is a file or a device.  If it's a
 * device, fill in the device id to make a complete nvlist.  Valid forms for a
 * leaf vdev are:
 *
 *  /dev/dsk/xxx    Complete disk path
 *  /xxx        Full path to file
 *  xxx     Shorthand for /dev/dsk/xxx
 */
static nvlist_t *
make_leaf_vdev(const char *arg, uint64_t is_log)
{
    char path[MAXPATHLEN];
    struct stat64 statbuf;
    nvlist_t *vdev = NULL;
    char *type = NULL;
    boolean_t wholedisk = B_FALSE;

    /*
     * Determine what type of vdev this is, and put the full path into
     * 'path'.  We detect whether this is a device of file afterwards by
     * checking the st_mode of the file.
     */
    if (arg[0] == '/') {
        /*
         * Complete device or file path.  Exact type is determined by
         * examining the file descriptor afterwards.
         */
        wholedisk = is_whole_disk(arg);
        if (!wholedisk && (stat64(arg, &statbuf) != 0)) {
            (void) fprintf(stderr,
                gettext("cannot open '%s': %s\n"),
                arg, strerror(errno));
            return (NULL);
        }

        (void) strlcpy(path, arg, sizeof (path));
    } else {
        /*
         * This may be a short path for a device, or it could be total
         * gibberish.  Check to see if it's a known device in
         * /dev/dsk/.  As part of this check, see if we've been given a
         * an entire disk (minus the slice number).
         */
        (void) snprintf(path, sizeof (path), "%s/%s", DISK_ROOT,
            arg);
        wholedisk = is_whole_disk(path);
        if (!wholedisk && (stat64(path, &statbuf) != 0)) {
            /*
             * If we got ENOENT, then the user gave us
             * gibberish, so try to direct them with a
             * reasonable error message.  Otherwise,
             * regurgitate strerror() since it's the best we
             * can do.
             */
            if (errno == ENOENT) {
                (void) fprintf(stderr,
                    gettext("cannot open '%s': no such "
                    "device in %s\n"), arg, DISK_ROOT);
                (void) fprintf(stderr,
                    gettext("must be a full path or "
                    "shorthand device name\n"));
                return (NULL);
            } else {
                (void) fprintf(stderr,
                    gettext("cannot open '%s': %s\n"),
                    path, strerror(errno));
                return (NULL);
            }
        }
    }

    /*
     * Determine whether this is a device or a file.
     */
    if (wholedisk || S_ISBLK(statbuf.st_mode)) {
        type = VDEV_TYPE_DISK;
    } else if (S_ISREG(statbuf.st_mode)) {
        type = VDEV_TYPE_FILE;
    } else {
        (void) fprintf(stderr, gettext("cannot use '%s': must be a "
            "block device or regular file\n"), path);
        return (NULL);
    }

    /*
     * Finally, we have the complete device or file, and we know that it is
     * acceptable to use.  Construct the nvlist to describe this vdev.  All
     * vdevs have a 'path' element, and devices also have a 'devid' element.
     */
    verify(nvlist_alloc(&vdev, NV_UNIQUE_NAME, 0) == 0);
    verify(nvlist_add_string(vdev, ZPOOL_CONFIG_PATH, path) == 0);
    verify(nvlist_add_string(vdev, ZPOOL_CONFIG_TYPE, type) == 0);
    verify(nvlist_add_uint64(vdev, ZPOOL_CONFIG_IS_LOG, is_log) == 0);
    if (strcmp(type, VDEV_TYPE_DISK) == 0)
        verify(nvlist_add_uint64(vdev, ZPOOL_CONFIG_WHOLE_DISK,
            (uint64_t)wholedisk) == 0);

    /*
     * For a whole disk, defer getting its devid until after labeling it.
     */
    if (S_ISBLK(statbuf.st_mode) && !wholedisk) {
        /*
         * Get the devid for the device.
         */
        int fd;
        ddi_devid_t devid;
        char *minor = NULL, *devid_str = NULL;

        if ((fd = open(path, O_RDONLY)) < 0) {
            (void) fprintf(stderr, gettext("cannot open '%s': "
                "%s\n"), path, strerror(errno));
            nvlist_free(vdev);
            return (NULL);
        }

        if (devid_get(fd, &devid) == 0) {
            if (devid_get_minor_name(fd, &minor) == 0 &&
                (devid_str = devid_str_encode(devid, minor)) !=
                NULL) {
                verify(nvlist_add_string(vdev,
                    ZPOOL_CONFIG_DEVID, devid_str) == 0);
            }
            if (devid_str != NULL)
                devid_str_free(devid_str);
            if (minor != NULL)
                devid_str_free(minor);
            devid_free(devid);
        }

        (void) close(fd);
    }

    return (vdev);
}

/*
 * Go through and verify the replication level of the pool is consistent.
 * Performs the following checks:
 *
 *  For the new spec, verifies that devices in mirrors and raidz are the
 *  same size.
 *
 *  If the current configuration already has inconsistent replication
 *  levels, ignore any other potential problems in the new spec.
 *
 *  Otherwise, make sure that the current spec (if there is one) and the new
 *  spec have consistent replication levels.
 */
typedef struct replication_level {
    char *zprl_type;
    uint64_t zprl_children;
    uint64_t zprl_parity;
} replication_level_t;

#define ZPOOL_FUZZ  (16 * 1024 * 1024)

/*
 * Given a list of toplevel vdevs, return the current replication level.  If
 * the config is inconsistent, then NULL is returned.  If 'fatal' is set, then
 * an error message will be displayed for each self-inconsistent vdev.
 */
static replication_level_t *
get_replication(nvlist_t *nvroot, boolean_t fatal)
{
    nvlist_t **top;
    uint_t t, toplevels;
    nvlist_t **child;
    uint_t c, children;
    nvlist_t *nv;
    char *type;
    replication_level_t lastrep, rep, *ret;
    boolean_t dontreport;

    ret = safe_malloc(sizeof (replication_level_t));

    verify(nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
        &top, &toplevels) == 0);

    lastrep.zprl_type = NULL;
    for (t = 0; t < toplevels; t++) {
        uint64_t is_log = B_FALSE;

        nv = top[t];

        /*
         * For separate logs we ignore the top level vdev replication
         * constraints.
         */
        (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_LOG, &is_log);
        if (is_log)
            continue;

        verify(nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE,
            &type) == 0);
        if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
            &child, &children) != 0) {
            /*
             * This is a 'file' or 'disk' vdev.
             */
            rep.zprl_type = type;
            rep.zprl_children = 1;
            rep.zprl_parity = 0;
        } else {
            uint64_t vdev_size;

            /*
             * This is a mirror or RAID-Z vdev.  Go through and make
             * sure the contents are all the same (files vs. disks),
             * keeping track of the number of elements in the
             * process.
             *
             * We also check that the size of each vdev (if it can
             * be determined) is the same.
             */
            rep.zprl_type = type;
            rep.zprl_children = 0;

            if (strcmp(type, VDEV_TYPE_RAIDZ) == 0) {
                verify(nvlist_lookup_uint64(nv,
                    ZPOOL_CONFIG_NPARITY,
                    &rep.zprl_parity) == 0);
                assert(rep.zprl_parity != 0);
            } else {
                rep.zprl_parity = 0;
            }

            /*
             * The 'dontreport' variable indicates that we've
             * already reported an error for this spec, so don't
             * bother doing it again.
             */
            type = NULL;
            dontreport = 0;
            vdev_size = -1ULL;
            for (c = 0; c < children; c++) {
                nvlist_t *cnv = child[c];
                char *path;
                struct stat64 statbuf;
                uint64_t size = -1ULL;
                char *childtype;
                int fd, err;

                rep.zprl_children++;

                verify(nvlist_lookup_string(cnv,
                    ZPOOL_CONFIG_TYPE, &childtype) == 0);

                /*
                 * If this is a replacing or spare vdev, then
                 * get the real first child of the vdev.
                 */
                if (strcmp(childtype,
                    VDEV_TYPE_REPLACING) == 0 ||
                    strcmp(childtype, VDEV_TYPE_SPARE) == 0) {
                    nvlist_t **rchild;
                    uint_t rchildren;

                    verify(nvlist_lookup_nvlist_array(cnv,
                        ZPOOL_CONFIG_CHILDREN, &rchild,
                        &rchildren) == 0);
                    assert(rchildren == 2);
                    cnv = rchild[0];

                    verify(nvlist_lookup_string(cnv,
                        ZPOOL_CONFIG_TYPE,
                        &childtype) == 0);
                }

                verify(nvlist_lookup_string(cnv,
                    ZPOOL_CONFIG_PATH, &path) == 0);

                /*
                 * If we have a raidz/mirror that combines disks
                 * with files, report it as an error.
                 */
                if (!dontreport && type != NULL &&
                    strcmp(type, childtype) != 0) {
                    if (ret != NULL)
                        free(ret);
                    ret = NULL;
                    if (fatal)
                        vdev_error(gettext(
                            "mismatched replication "
                            "level: %s contains both "
                            "files and devices\n"),
                            rep.zprl_type);
                    else
                        return (NULL);
                    dontreport = B_TRUE;
                }

                /*
                 * According to stat(2), the value of 'st_size'
                 * is undefined for block devices and character
                 * devices.  But there is no effective way to
                 * determine the real size in userland.
                 *
                 * Instead, we'll take advantage of an
                 * implementation detail of spec_size().  If the
                 * device is currently open, then we (should)
                 * return a valid size.
                 *
                 * If we still don't get a valid size (indicated
                 * by a size of 0 or MAXOFFSET_T), then ignore
                 * this device altogether.
                 */
                if ((fd = open(path, O_RDONLY)) >= 0) {
                    err = fstat64(fd, &statbuf);
                    (void) close(fd);
                } else {
                    err = stat64(path, &statbuf);
                }

                if (err != 0 ||
                    statbuf.st_size == 0 ||
                    statbuf.st_size == MAXOFFSET_T)
                    continue;

                size = statbuf.st_size;

                /*
                 * Also make sure that devices and
                 * slices have a consistent size.  If
                 * they differ by a significant amount
                 * (~16MB) then report an error.
                 */
                if (!dontreport &&
                    (vdev_size != -1ULL &&
                    (labs(size - vdev_size) >
                    ZPOOL_FUZZ))) {
                    if (ret != NULL)
                        free(ret);
                    ret = NULL;
                    if (fatal)
                        vdev_error(gettext(
                            "%s contains devices of "
                            "different sizes\n"),
                            rep.zprl_type);
                    else
                        return (NULL);
                    dontreport = B_TRUE;
                }

                type = childtype;
                vdev_size = size;
            }
        }

        /*
         * At this point, we have the replication of the last toplevel
         * vdev in 'rep'.  Compare it to 'lastrep' to see if its
         * different.
         */
        if (lastrep.zprl_type != NULL) {
            if (strcmp(lastrep.zprl_type, rep.zprl_type) != 0) {
                if (ret != NULL)
                    free(ret);
                ret = NULL;
                if (fatal)
                    vdev_error(gettext(
                        "mismatched replication level: "
                        "both %s and %s vdevs are "
                        "present\n"),
                        lastrep.zprl_type, rep.zprl_type);
                else
                    return (NULL);
            } else if (lastrep.zprl_parity != rep.zprl_parity) {
                if (ret)
                    free(ret);
                ret = NULL;
                if (fatal)
                    vdev_error(gettext(
                        "mismatched replication level: "
                        "both %llu and %llu device parity "
                        "%s vdevs are present\n"),
                        lastrep.zprl_parity,
                        rep.zprl_parity,
                        rep.zprl_type);
                else
                    return (NULL);
            } else if (lastrep.zprl_children != rep.zprl_children) {
                if (ret)
                    free(ret);
                ret = NULL;
                if (fatal)
                    vdev_error(gettext(
                        "mismatched replication level: "
                        "both %llu-way and %llu-way %s "
                        "vdevs are present\n"),
                        lastrep.zprl_children,
                        rep.zprl_children,
                        rep.zprl_type);
                else
                    return (NULL);
            }
        }
        lastrep = rep;
    }

    if (ret != NULL)
        *ret = rep;

    return (ret);
}

/*
 * Check the replication level of the vdev spec against the current pool.  Calls
 * get_replication() to make sure the new spec is self-consistent.  If the pool
 * has a consistent replication level, then we ignore any errors.  Otherwise,
 * report any difference between the two.
 */
static int
check_replication(nvlist_t *config, nvlist_t *newroot)
{
    nvlist_t **child;
    uint_t  children;
    replication_level_t *current = NULL, *new;
    int ret;

    /*
     * If we have a current pool configuration, check to see if it's
     * self-consistent.  If not, simply return success.
     */
    if (config != NULL) {
        nvlist_t *nvroot;

        verify(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
            &nvroot) == 0);
        if ((current = get_replication(nvroot, B_FALSE)) == NULL)
            return (0);
    }
    /*
     * for spares there may be no children, and therefore no
     * replication level to check
     */
    if ((nvlist_lookup_nvlist_array(newroot, ZPOOL_CONFIG_CHILDREN,
        &child, &children) != 0) || (children == 0)) {
        free(current);
        return (0);
    }

    /*
     * If all we have is logs then there's no replication level to check.
     */
    if (num_logs(newroot) == children) {
        free(current);
        return (0);
    }

    /*
     * Get the replication level of the new vdev spec, reporting any
     * inconsistencies found.
     */
    if ((new = get_replication(newroot, B_TRUE)) == NULL) {
        free(current);
        return (-1);
    }

    /*
     * Check to see if the new vdev spec matches the replication level of
     * the current pool.
     */
    ret = 0;
    if (current != NULL) {
        if (strcmp(current->zprl_type, new->zprl_type) != 0) {
            vdev_error(gettext(
                "mismatched replication level: pool uses %s "
                "and new vdev is %s\n"),
                current->zprl_type, new->zprl_type);
            ret = -1;
        } else if (current->zprl_parity != new->zprl_parity) {
            vdev_error(gettext(
                "mismatched replication level: pool uses %llu "
                "device parity and new vdev uses %llu\n"),
                current->zprl_parity, new->zprl_parity);
            ret = -1;
        } else if (current->zprl_children != new->zprl_children) {
            vdev_error(gettext(
                "mismatched replication level: pool uses %llu-way "
                "%s and new vdev uses %llu-way %s\n"),
                current->zprl_children, current->zprl_type,
                new->zprl_children, new->zprl_type);
            ret = -1;
        }
    }

    free(new);
    if (current != NULL)
        free(current);

    return (ret);
}

/*
 * Go through and find any whole disks in the vdev specification, labelling them
 * as appropriate.  When constructing the vdev spec, we were unable to open this
 * device in order to provide a devid.  Now that we have labelled the disk and
 * know that slice 0 is valid, we can construct the devid now.
 *
 * If the disk was already labeled with an EFI label, we will have gotten the
 * devid already (because we were able to open the whole disk).  Otherwise, we
 * need to get the devid after we label the disk.
 */
static int
make_disks(zpool_handle_t *zhp, nvlist_t *nv)
{
    nvlist_t **child;
    uint_t c, children;
    char *type, *path, *diskname;
    char buf[MAXPATHLEN];
    uint64_t wholedisk;
    int fd;
    int ret;
    ddi_devid_t devid;
    char *minor = NULL, *devid_str = NULL;

    verify(nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) == 0);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
        &child, &children) != 0) {

        if (strcmp(type, VDEV_TYPE_DISK) != 0)
            return (0);

        /*
         * We have a disk device.  Get the path to the device
         * and see if it's a whole disk by appending the backup
         * slice and stat()ing the device.
         */
        verify(nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &path) == 0);
        if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
            &wholedisk) != 0 || !wholedisk)
            return (0);

        diskname = strrchr(path, '/');
        assert(diskname != NULL);
        diskname++;
        if (zpool_label_disk(g_zfs, zhp, diskname) == -1)
            return (-1);

        /*
         * Fill in the devid, now that we've labeled the disk.
         */
        (void) snprintf(buf, sizeof (buf), "%ss0", path);
        if ((fd = open(buf, O_RDONLY)) < 0) {
            (void) fprintf(stderr,
                gettext("cannot open '%s': %s\n"),
                buf, strerror(errno));
            return (-1);
        }

        if (devid_get(fd, &devid) == 0) {
            if (devid_get_minor_name(fd, &minor) == 0 &&
                (devid_str = devid_str_encode(devid, minor)) !=
                NULL) {
                verify(nvlist_add_string(nv,
                    ZPOOL_CONFIG_DEVID, devid_str) == 0);
            }
            if (devid_str != NULL)
                devid_str_free(devid_str);
            if (minor != NULL)
                devid_str_free(minor);
            devid_free(devid);
        }

        /*
         * Update the path to refer to the 's0' slice.  The presence of
         * the 'whole_disk' field indicates to the CLI that we should
         * chop off the slice number when displaying the device in
         * future output.
         */
        verify(nvlist_add_string(nv, ZPOOL_CONFIG_PATH, buf) == 0);

        (void) close(fd);

        return (0);
    }

    for (c = 0; c < children; c++)
        if ((ret = make_disks(zhp, child[c])) != 0)
            return (ret);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_SPARES,
        &child, &children) == 0)
        for (c = 0; c < children; c++)
            if ((ret = make_disks(zhp, child[c])) != 0)
                return (ret);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_L2CACHE,
        &child, &children) == 0)
        for (c = 0; c < children; c++)
            if ((ret = make_disks(zhp, child[c])) != 0)
                return (ret);

    return (0);
}

/*
 * Determine if the given path is a hot spare within the given configuration.
 */
static boolean_t
is_spare(nvlist_t *config, const char *path)
{
    int fd;
    pool_state_t state;
    char *name = NULL;
    nvlist_t *label;
    uint64_t guid, spareguid;
    nvlist_t *nvroot;
    nvlist_t **spares;
    uint_t i, nspares;
    boolean_t inuse;

    if ((fd = open(path, O_RDONLY)) < 0)
        return (B_FALSE);

    if (zpool_in_use(g_zfs, fd, &state, &name, &inuse) != 0 ||
        !inuse ||
        state != POOL_STATE_SPARE ||
        zpool_read_label(fd, &label) != 0) {
        free(name);
        (void) close(fd);
        return (B_FALSE);
    }
    free(name);

    (void) close(fd);
    verify(nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) == 0);
    nvlist_free(label);

    verify(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
        &nvroot) == 0);
    if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
        &spares, &nspares) == 0) {
        for (i = 0; i < nspares; i++) {
            verify(nvlist_lookup_uint64(spares[i],
                ZPOOL_CONFIG_GUID, &spareguid) == 0);
            if (spareguid == guid)
                return (B_TRUE);
        }
    }

    return (B_FALSE);
}

/*
 * Go through and find any devices that are in use.  We rely on libdiskmgt for
 * the majority of this task.
 */
static int
check_in_use(nvlist_t *config, nvlist_t *nv, int force, int isreplacing,
    int isspare)
{
    nvlist_t **child;
    uint_t c, children;
    char *type, *path;
    int ret;
    char buf[MAXPATHLEN];
    uint64_t wholedisk;

    verify(nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) == 0);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
        &child, &children) != 0) {

        verify(nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &path) == 0);

        /*
         * As a generic check, we look to see if this is a replace of a
         * hot spare within the same pool.  If so, we allow it
         * regardless of what libdiskmgt or zpool_in_use() says.
         */
        if (isreplacing) {
            if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
                &wholedisk) == 0 && wholedisk)
                (void) snprintf(buf, sizeof (buf), "%ss0",
                    path);
            else
                (void) strlcpy(buf, path, sizeof (buf));
            if (is_spare(config, buf))
                return (0);
        }

        if (strcmp(type, VDEV_TYPE_DISK) == 0)
            ret = check_device(path, force, isspare);

        if (strcmp(type, VDEV_TYPE_FILE) == 0)
            ret = check_file(path, force, isspare);

        return (ret);
    }

    for (c = 0; c < children; c++)
        if ((ret = check_in_use(config, child[c], force,
            isreplacing, B_FALSE)) != 0)
            return (ret);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_SPARES,
        &child, &children) == 0)
        for (c = 0; c < children; c++)
            if ((ret = check_in_use(config, child[c], force,
                isreplacing, B_TRUE)) != 0)
                return (ret);

    if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_L2CACHE,
        &child, &children) == 0)
        for (c = 0; c < children; c++)
            if ((ret = check_in_use(config, child[c], force,
                isreplacing, B_FALSE)) != 0)
                return (ret);

    return (0);
}

static const char *
is_grouping(const char *type, int *mindev, int *maxdev)
{
    if (strncmp(type, "raidz", 5) == 0) {
        const char *p = type + 5;
        char *end;
        long nparity;

        if (*p == '\0') {
            nparity = 1;
        } else if (*p == '0') {
            return (NULL); /* no zero prefixes allowed */
        } else {
            errno = 0;
            nparity = strtol(p, &end, 10);
            if (errno != 0 || nparity < 1 || nparity >= 255 ||
                *end != '\0')
                return (NULL);
        }

        if (mindev != NULL)
            *mindev = nparity + 1;
        if (maxdev != NULL)
            *maxdev = 255;
        return (VDEV_TYPE_RAIDZ);
    }

    if (maxdev != NULL)
        *maxdev = INT_MAX;

    if (strcmp(type, "mirror") == 0) {
        if (mindev != NULL)
            *mindev = 2;
        return (VDEV_TYPE_MIRROR);
    }

    if (strcmp(type, "spare") == 0) {
        if (mindev != NULL)
            *mindev = 1;
        return (VDEV_TYPE_SPARE);
    }

    if (strcmp(type, "log") == 0) {
        if (mindev != NULL)
            *mindev = 1;
        return (VDEV_TYPE_LOG);
    }

    if (strcmp(type, "cache") == 0) {
        if (mindev != NULL)
            *mindev = 1;
        return (VDEV_TYPE_L2CACHE);
    }

    return (NULL);
}

/*
 * Construct a syntactically valid vdev specification,
 * and ensure that all devices and files exist and can be opened.
 * Note: we don't bother freeing anything in the error paths
 * because the program is just going to exit anyway.
 */
nvlist_t *
construct_spec(int argc, char **argv)
{
    nvlist_t *nvroot, *nv, **top, **spares, **l2cache;
    int t, toplevels, mindev, maxdev, nspares, nlogs, nl2cache;
    const char *type;
    uint64_t is_log;
    boolean_t seen_logs;

    top = NULL;
    toplevels = 0;
    spares = NULL;
    l2cache = NULL;
    nspares = 0;
    nlogs = 0;
    nl2cache = 0;
    is_log = B_FALSE;
    seen_logs = B_FALSE;

    while (argc > 0) {
        nv = NULL;

        /*
         * If it's a mirror or raidz, the subsequent arguments are
         * its leaves -- until we encounter the next mirror or raidz.
         */
        if ((type = is_grouping(argv[0], &mindev, &maxdev)) != NULL) {
            nvlist_t **child = NULL;
            int c, children = 0;

            if (strcmp(type, VDEV_TYPE_SPARE) == 0) {
                if (spares != NULL) {
                    (void) fprintf(stderr,
                        gettext("invalid vdev "
                        "specification: 'spare' can be "
                        "specified only once\n"));
                    return (NULL);
                }
                is_log = B_FALSE;
            }

            if (strcmp(type, VDEV_TYPE_LOG) == 0) {
                if (seen_logs) {
                    (void) fprintf(stderr,
                        gettext("invalid vdev "
                        "specification: 'log' can be "
                        "specified only once\n"));
                    return (NULL);
                }
                seen_logs = B_TRUE;
                is_log = B_TRUE;
                argc--;
                argv++;
                /*
                 * A log is not a real grouping device.
                 * We just set is_log and continue.
                 */
                continue;
            }

            if (strcmp(type, VDEV_TYPE_L2CACHE) == 0) {
                if (l2cache != NULL) {
                    (void) fprintf(stderr,
                        gettext("invalid vdev "
                        "specification: 'cache' can be "
                        "specified only once\n"));
                    return (NULL);
                }
                is_log = B_FALSE;
            }

            if (is_log) {
                if (strcmp(type, VDEV_TYPE_MIRROR) != 0) {
                    (void) fprintf(stderr,
                        gettext("invalid vdev "
                        "specification: unsupported 'log' "
                        "device: %s\n"), type);
                    return (NULL);
                }
                nlogs++;
            }

            for (c = 1; c < argc; c++) {
                if (is_grouping(argv[c], NULL, NULL) != NULL)
                    break;
                children++;
                child = realloc(child,
                    children * sizeof (nvlist_t *));
                if (child == NULL)
                    zpool_no_memory();
                if ((nv = make_leaf_vdev(argv[c], B_FALSE))
                    == NULL)
                    return (NULL);
                child[children - 1] = nv;
            }

            if (children < mindev) {
                (void) fprintf(stderr, gettext("invalid vdev "
                    "specification: %s requires at least %d "
                    "devices\n"), argv[0], mindev);
                return (NULL);
            }

            if (children > maxdev) {
                (void) fprintf(stderr, gettext("invalid vdev "
                    "specification: %s supports no more than "
                    "%d devices\n"), argv[0], maxdev);
                return (NULL);
            }

            argc -= c;
            argv += c;

            if (strcmp(type, VDEV_TYPE_SPARE) == 0) {
                spares = child;
                nspares = children;
                continue;
            } else if (strcmp(type, VDEV_TYPE_L2CACHE) == 0) {
                l2cache = child;
                nl2cache = children;
                continue;
            } else {
                verify(nvlist_alloc(&nv, NV_UNIQUE_NAME,
                    0) == 0);
                verify(nvlist_add_string(nv, ZPOOL_CONFIG_TYPE,
                    type) == 0);
                verify(nvlist_add_uint64(nv,
                    ZPOOL_CONFIG_IS_LOG, is_log) == 0);
                if (strcmp(type, VDEV_TYPE_RAIDZ) == 0) {
                    verify(nvlist_add_uint64(nv,
                        ZPOOL_CONFIG_NPARITY,
                        mindev - 1) == 0);
                }
                verify(nvlist_add_nvlist_array(nv,
                    ZPOOL_CONFIG_CHILDREN, child,
                    children) == 0);

                for (c = 0; c < children; c++)
                    nvlist_free(child[c]);
                free(child);
            }
        } else {
            /*
             * We have a device.  Pass off to make_leaf_vdev() to
             * construct the appropriate nvlist describing the vdev.
             */
            if ((nv = make_leaf_vdev(argv[0], is_log)) == NULL)
                return (NULL);
            if (is_log)
                nlogs++;
            argc--;
            argv++;
        }

        toplevels++;
        top = realloc(top, toplevels * sizeof (nvlist_t *));
        if (top == NULL)
            zpool_no_memory();
        top[toplevels - 1] = nv;
    }

    if (toplevels == 0 && nspares == 0 && nl2cache == 0) {
        (void) fprintf(stderr, gettext("invalid vdev "
            "specification: at least one toplevel vdev must be "
            "specified\n"));
        return (NULL);
    }

    if (seen_logs && nlogs == 0) {
        (void) fprintf(stderr, gettext("invalid vdev specification: "
            "log requires at least 1 device\n"));
        return (NULL);
    }

    /*
     * Finally, create nvroot and add all top-level vdevs to it.
     */
    verify(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, 0) == 0);
    verify(nvlist_add_string(nvroot, ZPOOL_CONFIG_TYPE,
        VDEV_TYPE_ROOT) == 0);
    verify(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
        top, toplevels) == 0);
    if (nspares != 0)
        verify(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
            spares, nspares) == 0);
    if (nl2cache != 0)
        verify(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE,
            l2cache, nl2cache) == 0);

    for (t = 0; t < toplevels; t++)
        nvlist_free(top[t]);
    for (t = 0; t < nspares; t++)
        nvlist_free(spares[t]);
    for (t = 0; t < nl2cache; t++)
        nvlist_free(l2cache[t]);
    if (spares)
        free(spares);
    if (l2cache)
        free(l2cache);
    free(top);

    return (nvroot);
}

nvlist_t *
split_mirror_vdev(zpool_handle_t *zhp, char *newname, nvlist_t *props,
    splitflags_t flags, int argc, char **argv)
{
    nvlist_t *newroot = NULL, **child;
    uint_t c, children;

    if (argc > 0) {
        if ((newroot = construct_spec(argc, argv)) == NULL) {
            (void) fprintf(stderr, gettext("Unable to build a "
                "pool from the specified devices\n"));
            return (NULL);
        }

        if (!flags.dryrun && make_disks(zhp, newroot) != 0) {
            nvlist_free(newroot);
            return (NULL);
        }

        /* avoid any tricks in the spec */
        verify(nvlist_lookup_nvlist_array(newroot,
            ZPOOL_CONFIG_CHILDREN, &child, &children) == 0);
        for (c = 0; c < children; c++) {
            char *path;
            const char *type;
            int min, max;

            verify(nvlist_lookup_string(child[c],
                ZPOOL_CONFIG_PATH, &path) == 0);
            if ((type = is_grouping(path, &min, &max)) != NULL) {
                (void) fprintf(stderr, gettext("Cannot use "
                    "'%s' as a device for splitting\n"), type);
                nvlist_free(newroot);
                return (NULL);
            }
        }
    }

    if (zpool_vdev_split(zhp, newname, &newroot, props, flags) != 0) {
        if (newroot != NULL)
            nvlist_free(newroot);
        return (NULL);
    }

    return (newroot);
}

/*
 * Get and validate the contents of the given vdev specification.  This ensures
 * that the nvlist returned is well-formed, that all the devices exist, and that
 * they are not currently in use by any other known consumer.  The 'poolconfig'
 * parameter is the current configuration of the pool when adding devices
 * existing pool, and is used to perform additional checks, such as changing the
 * replication level of the pool.  It can be 'NULL' to indicate that this is a
 * new pool.  The 'force' flag controls whether devices should be forcefully
 * added, even if they appear in use.
 */
nvlist_t *
make_root_vdev(zpool_handle_t *zhp, int force, int check_rep,
    boolean_t isreplacing, boolean_t dryrun, int argc, char **argv)
{
    nvlist_t *newroot;
    nvlist_t *poolconfig = NULL;
    is_force = force;

    /*
     * Construct the vdev specification.  If this is successful, we know
     * that we have a valid specification, and that all devices can be
     * opened.
     */
    if ((newroot = construct_spec(argc, argv)) == NULL)
        return (NULL);

    if (zhp && ((poolconfig = zpool_get_config(zhp, NULL)) == NULL))
        return (NULL);

    /*
     * Validate each device to make sure that its not shared with another
     * subsystem.  We do this even if 'force' is set, because there are some
     * uses (such as a dedicated dump device) that even '-f' cannot
     * override.
     */
    if (check_in_use(poolconfig, newroot, force, isreplacing,
        B_FALSE) != 0) {
        nvlist_free(newroot);
        return (NULL);
    }

    /*
     * Check the replication level of the given vdevs and report any errors
     * found.  We include the existing pool spec, if any, as we need to
     * catch changes against the existing replication level.
     */
    if (check_rep && check_replication(poolconfig, newroot) != 0) {
        nvlist_free(newroot);
        return (NULL);
    }

    /*
     * Run through the vdev specification and label any whole disks found.
     */
    if (!dryrun && make_disks(zhp, newroot) != 0) {
        nvlist_free(newroot);
        return (NULL);
    }

    return (newroot);
}