root/sys/geom/part/g_part.c
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2002, 2005-2009 Marcel Moolenaar
 * 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 ``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 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/param.h>
#include <sys/bio.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/uuid.h>
#include <geom/geom.h>
#include <geom/geom_ctl.h>
#include <geom/geom_int.h>
#include <geom/part/g_part.h>

#include "g_part_if.h"

static kobj_method_t g_part_null_methods[] = {
        { 0, 0 }
};

static struct g_part_scheme g_part_null_scheme = {
        "(none)",
        g_part_null_methods,
        sizeof(struct g_part_table),
};

TAILQ_HEAD(, g_part_scheme) g_part_schemes =
    TAILQ_HEAD_INITIALIZER(g_part_schemes);

struct g_part_alias_list {
        const char *lexeme;
        enum g_part_alias alias;
} g_part_alias_list[G_PART_ALIAS_COUNT] = {
        { "apple-apfs", G_PART_ALIAS_APPLE_APFS },
        { "apple-boot", G_PART_ALIAS_APPLE_BOOT },
        { "apple-core-storage", G_PART_ALIAS_APPLE_CORE_STORAGE },
        { "apple-hfs", G_PART_ALIAS_APPLE_HFS },
        { "apple-label", G_PART_ALIAS_APPLE_LABEL },
        { "apple-raid", G_PART_ALIAS_APPLE_RAID },
        { "apple-raid-offline", G_PART_ALIAS_APPLE_RAID_OFFLINE },
        { "apple-tv-recovery", G_PART_ALIAS_APPLE_TV_RECOVERY },
        { "apple-ufs", G_PART_ALIAS_APPLE_UFS },
        { "apple-zfs", G_PART_ALIAS_APPLE_ZFS },
        { "bios-boot", G_PART_ALIAS_BIOS_BOOT },
        { "chromeos-firmware", G_PART_ALIAS_CHROMEOS_FIRMWARE },
        { "chromeos-kernel", G_PART_ALIAS_CHROMEOS_KERNEL },
        { "chromeos-reserved", G_PART_ALIAS_CHROMEOS_RESERVED },
        { "chromeos-root", G_PART_ALIAS_CHROMEOS_ROOT },
        { "dragonfly-ccd", G_PART_ALIAS_DFBSD_CCD },
        { "dragonfly-hammer", G_PART_ALIAS_DFBSD_HAMMER },
        { "dragonfly-hammer2", G_PART_ALIAS_DFBSD_HAMMER2 },
        { "dragonfly-label32", G_PART_ALIAS_DFBSD },
        { "dragonfly-label64", G_PART_ALIAS_DFBSD64 },
        { "dragonfly-legacy", G_PART_ALIAS_DFBSD_LEGACY },
        { "dragonfly-swap", G_PART_ALIAS_DFBSD_SWAP },
        { "dragonfly-ufs", G_PART_ALIAS_DFBSD_UFS },
        { "dragonfly-vinum", G_PART_ALIAS_DFBSD_VINUM },
        { "ebr", G_PART_ALIAS_EBR },
        { "efi", G_PART_ALIAS_EFI },
        { "fat16", G_PART_ALIAS_MS_FAT16 },
        { "fat32", G_PART_ALIAS_MS_FAT32 },
        { "fat32lba", G_PART_ALIAS_MS_FAT32LBA },
        { "freebsd", G_PART_ALIAS_FREEBSD },
        { "freebsd-boot", G_PART_ALIAS_FREEBSD_BOOT },
        { "freebsd-nandfs", G_PART_ALIAS_FREEBSD_NANDFS },
        { "freebsd-swap", G_PART_ALIAS_FREEBSD_SWAP },
        { "freebsd-ufs", G_PART_ALIAS_FREEBSD_UFS },
        { "freebsd-vinum", G_PART_ALIAS_FREEBSD_VINUM },
        { "freebsd-zfs", G_PART_ALIAS_FREEBSD_ZFS },
        { "hifive-fsbl", G_PART_ALIAS_HIFIVE_FSBL },
        { "hifive-bbl", G_PART_ALIAS_HIFIVE_BBL },
        { "linux-data", G_PART_ALIAS_LINUX_DATA },
        { "linux-lvm", G_PART_ALIAS_LINUX_LVM },
        { "linux-raid", G_PART_ALIAS_LINUX_RAID },
        { "linux-swap", G_PART_ALIAS_LINUX_SWAP },
        { "mbr", G_PART_ALIAS_MBR },
        { "ms-basic-data", G_PART_ALIAS_MS_BASIC_DATA },
        { "ms-ldm-data", G_PART_ALIAS_MS_LDM_DATA },
        { "ms-ldm-metadata", G_PART_ALIAS_MS_LDM_METADATA },
        { "ms-recovery", G_PART_ALIAS_MS_RECOVERY },
        { "ms-reserved", G_PART_ALIAS_MS_RESERVED },
        { "ms-spaces", G_PART_ALIAS_MS_SPACES },
        { "netbsd-ccd", G_PART_ALIAS_NETBSD_CCD },
        { "netbsd-cgd", G_PART_ALIAS_NETBSD_CGD },
        { "netbsd-ffs", G_PART_ALIAS_NETBSD_FFS },
        { "netbsd-lfs", G_PART_ALIAS_NETBSD_LFS },
        { "netbsd-raid", G_PART_ALIAS_NETBSD_RAID },
        { "netbsd-swap", G_PART_ALIAS_NETBSD_SWAP },
        { "ntfs", G_PART_ALIAS_MS_NTFS },
        { "openbsd-data", G_PART_ALIAS_OPENBSD_DATA },
        { "prep-boot", G_PART_ALIAS_PREP_BOOT },
        { "solaris-boot", G_PART_ALIAS_SOLARIS_BOOT },
        { "solaris-root", G_PART_ALIAS_SOLARIS_ROOT },
        { "solaris-swap", G_PART_ALIAS_SOLARIS_SWAP },
        { "solaris-backup", G_PART_ALIAS_SOLARIS_BACKUP },
        { "solaris-var", G_PART_ALIAS_SOLARIS_VAR },
        { "solaris-home", G_PART_ALIAS_SOLARIS_HOME },
        { "solaris-altsec", G_PART_ALIAS_SOLARIS_ALTSEC },
        { "solaris-reserved", G_PART_ALIAS_SOLARIS_RESERVED },
        { "u-boot-env", G_PART_ALIAS_U_BOOT_ENV },
        { "vmware-reserved", G_PART_ALIAS_VMRESERVED },
        { "vmware-vmfs", G_PART_ALIAS_VMFS },
        { "vmware-vmkdiag", G_PART_ALIAS_VMKDIAG },
        { "vmware-vsanhdr", G_PART_ALIAS_VMVSANHDR },
        { "xbootldr", G_PART_ALIAS_XBOOTLDR },
};

SYSCTL_DECL(_kern_geom);
SYSCTL_NODE(_kern_geom, OID_AUTO, part, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "GEOM_PART stuff");
u_int geom_part_check_integrity = 1;
SYSCTL_UINT(_kern_geom_part, OID_AUTO, check_integrity,
    CTLFLAG_RWTUN, &geom_part_check_integrity, 1,
    "Enable integrity checking");
static u_int auto_resize = 1;
SYSCTL_UINT(_kern_geom_part, OID_AUTO, auto_resize,
    CTLFLAG_RWTUN, &auto_resize, 1,
    "Enable auto resize");
static u_int allow_nesting = 0;
SYSCTL_UINT(_kern_geom_part, OID_AUTO, allow_nesting,
    CTLFLAG_RWTUN, &allow_nesting, 0,
    "Allow additional levels of nesting");
char g_part_separator[MAXPATHLEN] = "";
SYSCTL_STRING(_kern_geom_part, OID_AUTO, separator,
    CTLFLAG_RDTUN, &g_part_separator, sizeof(g_part_separator),
    "Partition name separator");

/*
 * The GEOM partitioning class.
 */
static g_ctl_req_t g_part_ctlreq;
static g_ctl_destroy_geom_t g_part_destroy_geom;
static g_fini_t g_part_fini;
static g_init_t g_part_init;
static g_taste_t g_part_taste;

static g_access_t g_part_access;
static g_dumpconf_t g_part_dumpconf;
static g_orphan_t g_part_orphan;
static g_spoiled_t g_part_spoiled;
static g_start_t g_part_start;
static g_resize_t g_part_resize;
static g_ioctl_t g_part_ioctl;

static struct g_class g_part_class = {
        .name = "PART",
        .version = G_VERSION,
        /* Class methods. */
        .ctlreq = g_part_ctlreq,
        .destroy_geom = g_part_destroy_geom,
        .fini = g_part_fini,
        .init = g_part_init,
        .taste = g_part_taste,
        /* Geom methods. */
        .access = g_part_access,
        .dumpconf = g_part_dumpconf,
        .orphan = g_part_orphan,
        .spoiled = g_part_spoiled,
        .start = g_part_start,
        .resize = g_part_resize,
        .ioctl = g_part_ioctl,
};

DECLARE_GEOM_CLASS(g_part_class, g_part);
MODULE_VERSION(g_part, 0);

/*
 * Support functions.
 */

static void g_part_wither(struct g_geom *, int);

const char *
g_part_alias_name(enum g_part_alias alias)
{
        int i;

        for (i = 0; i < G_PART_ALIAS_COUNT; i++) {
                if (g_part_alias_list[i].alias != alias)
                        continue;
                return (g_part_alias_list[i].lexeme);
        }

        return (NULL);
}

void
g_part_geometry_heads(off_t blocks, u_int sectors, off_t *bestchs,
    u_int *bestheads)
{
        static u_int candidate_heads[] = { 1, 2, 16, 32, 64, 128, 255, 0 };
        off_t chs, cylinders;
        u_int heads;
        int idx;

        *bestchs = 0;
        *bestheads = 0;
        for (idx = 0; candidate_heads[idx] != 0; idx++) {
                heads = candidate_heads[idx];
                cylinders = blocks / heads / sectors;
                if (cylinders < heads || cylinders < sectors)
                        break;
                if (cylinders > 1023)
                        continue;
                chs = cylinders * heads * sectors;
                if (chs > *bestchs || (chs == *bestchs && *bestheads == 1)) {
                        *bestchs = chs;
                        *bestheads = heads;
                }
        }
}

static void
g_part_geometry(struct g_part_table *table, struct g_consumer *cp,
    off_t blocks)
{
        static u_int candidate_sectors[] = { 1, 9, 17, 33, 63, 0 };
        off_t chs, bestchs;
        u_int heads, sectors;
        int idx;

        if (g_getattr("GEOM::fwsectors", cp, &sectors) != 0 || sectors == 0 ||
            g_getattr("GEOM::fwheads", cp, &heads) != 0 || heads == 0) {
                table->gpt_fixgeom = 0;
                table->gpt_heads = 0;
                table->gpt_sectors = 0;
                bestchs = 0;
                for (idx = 0; candidate_sectors[idx] != 0; idx++) {
                        sectors = candidate_sectors[idx];
                        g_part_geometry_heads(blocks, sectors, &chs, &heads);
                        if (chs == 0)
                                continue;
                        /*
                         * Prefer a geometry with sectors > 1, but only if
                         * it doesn't bump down the number of heads to 1.
                         */
                        if (chs > bestchs || (chs == bestchs && heads > 1 &&
                            table->gpt_sectors == 1)) {
                                bestchs = chs;
                                table->gpt_heads = heads;
                                table->gpt_sectors = sectors;
                        }
                }
                /*
                 * If we didn't find a geometry at all, then the disk is
                 * too big. This means we can use the maximum number of
                 * heads and sectors.
                 */
                if (bestchs == 0) {
                        table->gpt_heads = 255;
                        table->gpt_sectors = 63;
                }
        } else {
                table->gpt_fixgeom = 1;
                table->gpt_heads = heads;
                table->gpt_sectors = sectors;
        }
}

static void
g_part_get_physpath_done(struct bio *bp)
{
        struct g_geom *gp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct g_provider *pp;
        struct bio *pbp;

        pbp = bp->bio_parent;
        pp = pbp->bio_to;
        gp = pp->geom;
        table = gp->softc;
        entry = pp->private;

        if (bp->bio_error == 0) {
                char *end;
                size_t len, remainder;
                len = strlcat(bp->bio_data, "/", bp->bio_length);
                if (len < bp->bio_length) {
                        end = bp->bio_data + len;
                        remainder = bp->bio_length - len;
                        G_PART_NAME(table, entry, end, remainder);
                }
        }
        g_std_done(bp);
}

#define DPRINTF(...)    if (bootverbose) {      \
        printf("GEOM_PART: " __VA_ARGS__);      \
}

static int
g_part_check_integrity(struct g_part_table *table, struct g_consumer *cp)
{
        struct g_part_entry *e1, *e2;
        struct g_provider *pp;
        off_t offset;
        int failed;

        failed = 0;
        pp = cp->provider;
        if (table->gpt_last < table->gpt_first) {
                DPRINTF("last LBA is below first LBA: %jd < %jd\n",
                    (intmax_t)table->gpt_last, (intmax_t)table->gpt_first);
                failed++;
        }
        if (table->gpt_last > pp->mediasize / pp->sectorsize - 1) {
                DPRINTF("last LBA extends beyond mediasize: "
                    "%jd > %jd\n", (intmax_t)table->gpt_last,
                    (intmax_t)pp->mediasize / pp->sectorsize - 1);
                failed++;
        }
        LIST_FOREACH(e1, &table->gpt_entry, gpe_entry) {
                if (e1->gpe_deleted || e1->gpe_internal)
                        continue;
                if (e1->gpe_start < table->gpt_first) {
                        DPRINTF("partition %d has start offset below first "
                            "LBA: %jd < %jd\n", e1->gpe_index,
                            (intmax_t)e1->gpe_start,
                            (intmax_t)table->gpt_first);
                        failed++;
                }
                if (e1->gpe_start > table->gpt_last) {
                        DPRINTF("partition %d has start offset beyond last "
                            "LBA: %jd > %jd\n", e1->gpe_index,
                            (intmax_t)e1->gpe_start,
                            (intmax_t)table->gpt_last);
                        failed++;
                }
                if (e1->gpe_end < e1->gpe_start) {
                        DPRINTF("partition %d has end offset below start "
                            "offset: %jd < %jd\n", e1->gpe_index,
                            (intmax_t)e1->gpe_end,
                            (intmax_t)e1->gpe_start);
                        failed++;
                }
                if (e1->gpe_end > table->gpt_last) {
                        DPRINTF("partition %d has end offset beyond last "
                            "LBA: %jd > %jd\n", e1->gpe_index,
                            (intmax_t)e1->gpe_end,
                            (intmax_t)table->gpt_last);
                        failed++;
                }
                if (pp->stripesize > 0) {
                        offset = e1->gpe_start * pp->sectorsize;
                        if (e1->gpe_offset > offset)
                                offset = e1->gpe_offset;
                        if ((offset + pp->stripeoffset) % pp->stripesize) {
                                DPRINTF("partition %d on (%s, %s) is not "
                                    "aligned on %ju bytes\n", e1->gpe_index,
                                    pp->name, table->gpt_scheme->name,
                                    (uintmax_t)pp->stripesize);
                                /* Don't treat this as a critical failure */
                        }
                }
                e2 = e1;
                while ((e2 = LIST_NEXT(e2, gpe_entry)) != NULL) {
                        if (e2->gpe_deleted || e2->gpe_internal)
                                continue;
                        if (e1->gpe_start >= e2->gpe_start &&
                            e1->gpe_start <= e2->gpe_end) {
                                DPRINTF("partition %d has start offset inside "
                                    "partition %d: start[%d] %jd >= start[%d] "
                                    "%jd <= end[%d] %jd\n",
                                    e1->gpe_index, e2->gpe_index,
                                    e2->gpe_index, (intmax_t)e2->gpe_start,
                                    e1->gpe_index, (intmax_t)e1->gpe_start,
                                    e2->gpe_index, (intmax_t)e2->gpe_end);
                                failed++;
                        }
                        if (e1->gpe_end >= e2->gpe_start &&
                            e1->gpe_end <= e2->gpe_end) {
                                DPRINTF("partition %d has end offset inside "
                                    "partition %d: start[%d] %jd >= end[%d] "
                                    "%jd <= end[%d] %jd\n",
                                    e1->gpe_index, e2->gpe_index,
                                    e2->gpe_index, (intmax_t)e2->gpe_start,
                                    e1->gpe_index, (intmax_t)e1->gpe_end,
                                    e2->gpe_index, (intmax_t)e2->gpe_end);
                                failed++;
                        }
                        if (e1->gpe_start < e2->gpe_start &&
                            e1->gpe_end > e2->gpe_end) {
                                DPRINTF("partition %d contains partition %d: "
                                    "start[%d] %jd > start[%d] %jd, end[%d] "
                                    "%jd < end[%d] %jd\n",
                                    e1->gpe_index, e2->gpe_index,
                                    e1->gpe_index, (intmax_t)e1->gpe_start,
                                    e2->gpe_index, (intmax_t)e2->gpe_start,
                                    e2->gpe_index, (intmax_t)e2->gpe_end,
                                    e1->gpe_index, (intmax_t)e1->gpe_end);
                                failed++;
                        }
                }
        }
        if (failed != 0) {
                printf("GEOM_PART: integrity check failed (%s, %s)\n",
                    pp->name, table->gpt_scheme->name);
                if (geom_part_check_integrity != 0)
                        return (EINVAL);
                table->gpt_corrupt = 1;
        }
        return (0);
}
#undef  DPRINTF

struct g_part_entry *
g_part_new_entry(struct g_part_table *table, int index, quad_t start,
    quad_t end)
{
        struct g_part_entry *entry, *last;

        last = NULL;
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_index == index)
                        break;
                if (entry->gpe_index > index) {
                        entry = NULL;
                        break;
                }
                last = entry;
        }
        if (entry == NULL) {
                entry = g_malloc(table->gpt_scheme->gps_entrysz,
                    M_WAITOK | M_ZERO);
                entry->gpe_index = index;
                if (last == NULL)
                        LIST_INSERT_HEAD(&table->gpt_entry, entry, gpe_entry);
                else
                        LIST_INSERT_AFTER(last, entry, gpe_entry);
        } else
                entry->gpe_offset = 0;
        entry->gpe_start = start;
        entry->gpe_end = end;
        return (entry);
}

static void
g_part_new_provider(struct g_geom *gp, struct g_part_table *table,
    struct g_part_entry *entry)
{
        struct g_consumer *cp;
        struct g_provider *pp;
        struct g_geom_alias *gap;
        off_t offset;

        cp = LIST_FIRST(&gp->consumer);
        pp = cp->provider;

        offset = entry->gpe_start * pp->sectorsize;
        if (entry->gpe_offset < offset)
                entry->gpe_offset = offset;

        if (entry->gpe_pp == NULL) {
                entry->gpe_pp = G_PART_NEW_PROVIDER(table, gp, entry, gp->name);
                /*
                 * If our parent provider had any aliases, then copy them to our
                 * provider so when geom DEV tastes things later, they will be
                 * there for it to create the aliases with those name used in
                 * place of the geom's name we use to create the provider. The
                 * kobj interface that generates names makes this awkward.
                 */
                LIST_FOREACH(gap, &pp->aliases, ga_next)
                        G_PART_ADD_ALIAS(table, entry->gpe_pp, entry, gap->ga_alias);
                entry->gpe_pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
                entry->gpe_pp->private = entry;         /* Close the circle. */
        }
        entry->gpe_pp->index = entry->gpe_index - 1;    /* index is 1-based. */
        entry->gpe_pp->mediasize = (entry->gpe_end - entry->gpe_start + 1) *
            pp->sectorsize;
        entry->gpe_pp->mediasize -= entry->gpe_offset - offset;
        entry->gpe_pp->sectorsize = pp->sectorsize;
        entry->gpe_pp->stripesize = pp->stripesize;
        entry->gpe_pp->stripeoffset = pp->stripeoffset + entry->gpe_offset;
        if (pp->stripesize > 0)
                entry->gpe_pp->stripeoffset %= pp->stripesize;
        entry->gpe_pp->flags |= pp->flags & G_PF_ACCEPT_UNMAPPED;
        g_error_provider(entry->gpe_pp, 0);
}

static struct g_geom*
g_part_find_geom(const char *name)
{
        struct g_geom *gp;
        LIST_FOREACH(gp, &g_part_class.geom, geom) {
                if ((gp->flags & G_GEOM_WITHER) == 0 &&
                    strcmp(name, gp->name) == 0)
                        break;
        }
        return (gp);
}

static int
g_part_parm_geom(struct gctl_req *req, const char *name, struct g_geom **v)
{
        struct g_geom *gp;
        const char *gname;

        gname = gctl_get_asciiparam(req, name);
        if (gname == NULL)
                return (ENOATTR);
        if (strncmp(gname, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
                gname += sizeof(_PATH_DEV) - 1;
        gp = g_part_find_geom(gname);
        if (gp == NULL) {
                gctl_error(req, "%d %s '%s'", EINVAL, name, gname);
                return (EINVAL);
        }
        *v = gp;
        return (0);
}

static int
g_part_parm_provider(struct gctl_req *req, const char *name,
    struct g_provider **v)
{
        struct g_provider *pp;
        const char *pname;

        pname = gctl_get_asciiparam(req, name);
        if (pname == NULL)
                return (ENOATTR);
        pp = g_provider_by_name(pname);
        if (pp == NULL) {
                gctl_error(req, "%d %s '%s'", EINVAL, name, pname);
                return (EINVAL);
        }
        *v = pp;
        return (0);
}

static int
g_part_parm_quad(struct gctl_req *req, const char *name, quad_t *v)
{
        const char *p;
        char *x;
        quad_t q;

        p = gctl_get_asciiparam(req, name);
        if (p == NULL)
                return (ENOATTR);
        q = strtoq(p, &x, 0);
        if (*x != '\0' || q < 0) {
                gctl_error(req, "%d %s '%s'", EINVAL, name, p);
                return (EINVAL);
        }
        *v = q;
        return (0);
}

static int
g_part_parm_scheme(struct gctl_req *req, const char *name,
    struct g_part_scheme **v)
{
        struct g_part_scheme *s;
        const char *p;

        p = gctl_get_asciiparam(req, name);
        if (p == NULL)
                return (ENOATTR);
        TAILQ_FOREACH(s, &g_part_schemes, scheme_list) {
                if (s == &g_part_null_scheme)
                        continue;
                if (!strcasecmp(s->name, p))
                        break;
        }
        if (s == NULL) {
                gctl_error(req, "%d %s '%s'", EINVAL, name, p);
                return (EINVAL);
        }
        *v = s;
        return (0);
}

static int
g_part_parm_str(struct gctl_req *req, const char *name, const char **v)
{
        const char *p;

        p = gctl_get_asciiparam(req, name);
        if (p == NULL)
                return (ENOATTR);
        /* An empty label is always valid. */
        if (strcmp(name, "label") != 0 && p[0] == '\0') {
                gctl_error(req, "%d %s '%s'", EINVAL, name, p);
                return (EINVAL);
        }
        *v = p;
        return (0);
}

static int
g_part_parm_intmax(struct gctl_req *req, const char *name, u_int *v)
{
        const intmax_t *p;
        int size;

        p = gctl_get_param(req, name, &size);
        if (p == NULL)
                return (ENOATTR);
        if (size != sizeof(*p) || *p < 0 || *p > INT_MAX) {
                gctl_error(req, "%d %s '%jd'", EINVAL, name, *p);
                return (EINVAL);
        }
        *v = (u_int)*p;
        return (0);
}

static int
g_part_parm_uint32(struct gctl_req *req, const char *name, u_int *v)
{
        const uint32_t *p;
        int size;

        p = gctl_get_param(req, name, &size);
        if (p == NULL)
                return (ENOATTR);
        if (size != sizeof(*p) || *p > INT_MAX) {
                gctl_error(req, "%d %s '%u'", EINVAL, name, (unsigned int)*p);
                return (EINVAL);
        }
        *v = (u_int)*p;
        return (0);
}

static int
g_part_parm_bootcode(struct gctl_req *req, const char *name, const void **v,
    unsigned int *s)
{
        const void *p;
        int size;

        p = gctl_get_param(req, name, &size);
        if (p == NULL)
                return (ENOATTR);
        *v = p;
        *s = size;
        return (0);
}

static int
g_part_probe(struct g_geom *gp, struct g_consumer *cp, int depth)
{
        struct g_part_scheme *iter, *scheme;
        struct g_part_table *table;
        int pri, probe;

        table = gp->softc;
        scheme = (table != NULL) ? table->gpt_scheme : NULL;
        pri = (scheme != NULL) ? G_PART_PROBE(table, cp) : INT_MIN;
        if (pri == 0)
                goto done;
        if (pri > 0) {  /* error */
                scheme = NULL;
                pri = INT_MIN;
        }

        TAILQ_FOREACH(iter, &g_part_schemes, scheme_list) {
                if (iter == &g_part_null_scheme)
                        continue;
                table = (void *)kobj_create((kobj_class_t)iter, M_GEOM,
                    M_WAITOK);
                table->gpt_gp = gp;
                table->gpt_scheme = iter;
                table->gpt_depth = depth;
                probe = G_PART_PROBE(table, cp);
                if (probe <= 0 && probe > pri) {
                        pri = probe;
                        scheme = iter;
                        if (gp->softc != NULL)
                                kobj_delete((kobj_t)gp->softc, M_GEOM);
                        gp->softc = table;
                        if (pri == 0)
                                goto done;
                } else
                        kobj_delete((kobj_t)table, M_GEOM);
        }

done:
        return ((scheme == NULL) ? ENXIO : 0);
}

/*
 * Control request functions.
 */

static int
g_part_ctl_add(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_entry *delent, *last, *entry;
        struct g_part_table *table;
        struct sbuf *sb;
        quad_t end;
        unsigned int index;
        int error;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        pp = LIST_FIRST(&gp->consumer)->provider;
        table = gp->softc;
        end = gpp->gpp_start + gpp->gpp_size - 1;

        if (gpp->gpp_start < table->gpt_first ||
            gpp->gpp_start > table->gpt_last) {
                gctl_error(req, "%d start '%jd'", EINVAL,
                    (intmax_t)gpp->gpp_start);
                return (EINVAL);
        }
        if (end < gpp->gpp_start || end > table->gpt_last) {
                gctl_error(req, "%d size '%jd'", EINVAL,
                    (intmax_t)gpp->gpp_size);
                return (EINVAL);
        }
        if (gpp->gpp_index > table->gpt_entries) {
                gctl_error(req, "%d index '%d'", EINVAL, gpp->gpp_index);
                return (EINVAL);
        }

        delent = last = NULL;
        index = (gpp->gpp_index > 0) ? gpp->gpp_index : 1;
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_deleted) {
                        if (entry->gpe_index == index)
                                delent = entry;
                        continue;
                }
                if (entry->gpe_index == index)
                        index = entry->gpe_index + 1;
                if (entry->gpe_index < index)
                        last = entry;
                if (entry->gpe_internal)
                        continue;
                if (gpp->gpp_start >= entry->gpe_start &&
                    gpp->gpp_start <= entry->gpe_end) {
                        gctl_error(req, "%d start '%jd'", ENOSPC,
                            (intmax_t)gpp->gpp_start);
                        return (ENOSPC);
                }
                if (end >= entry->gpe_start && end <= entry->gpe_end) {
                        gctl_error(req, "%d end '%jd'", ENOSPC, (intmax_t)end);
                        return (ENOSPC);
                }
                if (gpp->gpp_start < entry->gpe_start && end > entry->gpe_end) {
                        gctl_error(req, "%d size '%jd'", ENOSPC,
                            (intmax_t)gpp->gpp_size);
                        return (ENOSPC);
                }
        }
        if (gpp->gpp_index > 0 && index != gpp->gpp_index) {
                gctl_error(req, "%d index '%d'", EEXIST, gpp->gpp_index);
                return (EEXIST);
        }
        if (index > table->gpt_entries) {
                gctl_error(req, "%d index '%d'", ENOSPC, index);
                return (ENOSPC);
        }

        entry = (delent == NULL) ? g_malloc(table->gpt_scheme->gps_entrysz,
            M_WAITOK | M_ZERO) : delent;
        entry->gpe_index = index;
        entry->gpe_start = gpp->gpp_start;
        entry->gpe_end = end;
        error = G_PART_ADD(table, entry, gpp);
        if (error) {
                gctl_error(req, "%d", error);
                if (delent == NULL)
                        g_free(entry);
                return (error);
        }
        if (delent == NULL) {
                if (last == NULL)
                        LIST_INSERT_HEAD(&table->gpt_entry, entry, gpe_entry);
                else
                        LIST_INSERT_AFTER(last, entry, gpe_entry);
                entry->gpe_created = 1;
        } else {
                entry->gpe_deleted = 0;
                entry->gpe_modified = 1;
        }
        g_part_new_provider(gp, table, entry);

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                G_PART_FULLNAME(table, entry, sb, gp->name);
                if (pp->stripesize > 0 && entry->gpe_pp->stripeoffset != 0)
                        sbuf_printf(sb, " added, but partition is not "
                            "aligned on %ju bytes\n", (uintmax_t)pp->stripesize);
                else
                        sbuf_cat(sb, " added\n");
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_bootcode(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_geom *gp;
        struct g_part_table *table;
        struct sbuf *sb;
        int error, sz;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;
        sz = table->gpt_scheme->gps_bootcodesz;
        if (sz == 0) {
                error = ENODEV;
                goto fail;
        }
        if (gpp->gpp_codesize > sz) {
                error = EFBIG;
                goto fail;
        }

        error = G_PART_BOOTCODE(table, gpp);
        if (error)
                goto fail;

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                sbuf_printf(sb, "bootcode written to %s\n", gp->name);
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);

 fail:
        gctl_error(req, "%d", error);
        return (error);
}

static int
g_part_ctl_commit(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_entry *entry, *tmp;
        struct g_part_table *table;
        char *buf;
        int error, i;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;
        if (!table->gpt_opened) {
                gctl_error(req, "%d", EPERM);
                return (EPERM);
        }

        g_topology_unlock();

        cp = LIST_FIRST(&gp->consumer);
        if ((table->gpt_smhead | table->gpt_smtail) != 0) {
                pp = cp->provider;
                buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
                while (table->gpt_smhead != 0) {
                        i = ffs(table->gpt_smhead) - 1;
                        error = g_write_data(cp, i * pp->sectorsize, buf,
                            pp->sectorsize);
                        if (error) {
                                g_free(buf);
                                goto fail;
                        }
                        table->gpt_smhead &= ~(1 << i);
                }
                while (table->gpt_smtail != 0) {
                        i = ffs(table->gpt_smtail) - 1;
                        error = g_write_data(cp, pp->mediasize - (i + 1) *
                            pp->sectorsize, buf, pp->sectorsize);
                        if (error) {
                                g_free(buf);
                                goto fail;
                        }
                        table->gpt_smtail &= ~(1 << i);
                }
                g_free(buf);
        }

        if (table->gpt_scheme == &g_part_null_scheme) {
                g_topology_lock();
                g_access(cp, -1, -1, -1);
                g_part_wither(gp, ENXIO);
                return (0);
        }

        error = G_PART_WRITE(table, cp);
        if (error)
                goto fail;

        LIST_FOREACH_SAFE(entry, &table->gpt_entry, gpe_entry, tmp) {
                if (!entry->gpe_deleted) {
                        /* Notify consumers that provider might be changed. */
                        if (entry->gpe_modified && (
                            entry->gpe_pp->acw + entry->gpe_pp->ace +
                            entry->gpe_pp->acr) == 0)
                                g_media_changed(entry->gpe_pp, M_NOWAIT);
                        entry->gpe_created = 0;
                        entry->gpe_modified = 0;
                        continue;
                }
                LIST_REMOVE(entry, gpe_entry);
                g_free(entry);
        }
        table->gpt_created = 0;
        table->gpt_opened = 0;

        g_topology_lock();
        g_access(cp, -1, -1, -1);
        return (0);

fail:
        g_topology_lock();
        gctl_error(req, "%d", error);
        return (error);
}

static int
g_part_ctl_create(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_scheme *scheme;
        struct g_part_table *null, *table;
        struct sbuf *sb;
        int attr, error;

        pp = gpp->gpp_provider;
        scheme = gpp->gpp_scheme;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, pp->name));
        g_topology_assert();

        /* Check that there isn't already a g_part geom on the provider. */
        gp = g_part_find_geom(pp->name);
        if (gp != NULL) {
                null = gp->softc;
                if (null->gpt_scheme != &g_part_null_scheme) {
                        gctl_error(req, "%d geom '%s'", EEXIST, pp->name);
                        return (EEXIST);
                }
        } else
                null = NULL;

        if ((gpp->gpp_parms & G_PART_PARM_ENTRIES) &&
            (gpp->gpp_entries < scheme->gps_minent ||
             gpp->gpp_entries > scheme->gps_maxent)) {
                gctl_error(req, "%d entries '%d'", EINVAL, gpp->gpp_entries);
                return (EINVAL);
        }

        if (null == NULL)
                gp = g_new_geom(&g_part_class, pp->name);
        gp->softc = kobj_create((kobj_class_t)gpp->gpp_scheme, M_GEOM,
            M_WAITOK);
        table = gp->softc;
        table->gpt_gp = gp;
        table->gpt_scheme = gpp->gpp_scheme;
        table->gpt_entries = (gpp->gpp_parms & G_PART_PARM_ENTRIES) ?
            gpp->gpp_entries : scheme->gps_defent;
        LIST_INIT(&table->gpt_entry);
        if (null == NULL) {
                cp = g_new_consumer(gp);
                cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
                error = g_attach(cp, pp);
                if (error == 0)
                        error = g_access(cp, 1, 1, 1);
                if (error != 0) {
                        g_part_wither(gp, error);
                        gctl_error(req, "%d geom '%s'", error, pp->name);
                        return (error);
                }
                table->gpt_opened = 1;
        } else {
                cp = LIST_FIRST(&gp->consumer);
                table->gpt_opened = null->gpt_opened;
                table->gpt_smhead = null->gpt_smhead;
                table->gpt_smtail = null->gpt_smtail;
        }

        g_topology_unlock();

        /* Make sure the provider has media. */
        if (pp->mediasize == 0 || pp->sectorsize == 0) {
                error = ENODEV;
                goto fail;
        }

        /* Make sure we can nest and if so, determine our depth. */
        error = g_getattr("PART::isleaf", cp, &attr);
        if (!error && attr) {
                error = ENODEV;
                goto fail;
        }
        error = g_getattr("PART::depth", cp, &attr);
        table->gpt_depth = (!error) ? attr + 1 : 0;

        /*
         * Synthesize a disk geometry. Some partitioning schemes
         * depend on it and since some file systems need it even
         * when the partition scheme doesn't, we do it here in
         * scheme-independent code.
         */
        g_part_geometry(table, cp, pp->mediasize / pp->sectorsize);

        error = G_PART_CREATE(table, gpp);
        if (error)
                goto fail;

        g_topology_lock();

        table->gpt_created = 1;
        if (null != NULL)
                kobj_delete((kobj_t)null, M_GEOM);

        /*
         * Support automatic commit by filling in the gpp_geom
         * parameter.
         */
        gpp->gpp_parms |= G_PART_PARM_GEOM;
        gpp->gpp_geom = gp;

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                sbuf_printf(sb, "%s created\n", gp->name);
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);

fail:
        g_topology_lock();
        if (null == NULL) {
                g_access(cp, -1, -1, -1);
                g_part_wither(gp, error);
        } else {
                kobj_delete((kobj_t)gp->softc, M_GEOM);
                gp->softc = null;
        }
        gctl_error(req, "%d provider", error);
        return (error);
}

static int
g_part_ctl_delete(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct sbuf *sb;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;

        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_deleted || entry->gpe_internal)
                        continue;
                if (entry->gpe_index == gpp->gpp_index)
                        break;
        }
        if (entry == NULL) {
                gctl_error(req, "%d index '%d'", ENOENT, gpp->gpp_index);
                return (ENOENT);
        }

        pp = entry->gpe_pp;
        if (pp != NULL) {
                if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) {
                        gctl_error(req, "%d", EBUSY);
                        return (EBUSY);
                }

                pp->private = NULL;
                entry->gpe_pp = NULL;
        }

        if (pp != NULL)
                g_wither_provider(pp, ENXIO);

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                G_PART_FULLNAME(table, entry, sb, gp->name);
                sbuf_cat(sb, " deleted\n");
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }

        if (entry->gpe_created) {
                LIST_REMOVE(entry, gpe_entry);
                g_free(entry);
        } else {
                entry->gpe_modified = 0;
                entry->gpe_deleted = 1;
        }
        return (0);
}

static int
g_part_ctl_destroy(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_entry *entry, *tmp;
        struct g_part_table *null, *table;
        struct sbuf *sb;
        int error;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;
        /* Check for busy providers. */
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_deleted || entry->gpe_internal)
                        continue;
                if (gpp->gpp_force) {
                        pp = entry->gpe_pp;
                        if (pp == NULL)
                                continue;
                        if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
                                continue;
                }
                gctl_error(req, "%d", EBUSY);
                return (EBUSY);
        }

        if (gpp->gpp_force) {
                /* Destroy all providers. */
                LIST_FOREACH_SAFE(entry, &table->gpt_entry, gpe_entry, tmp) {
                        pp = entry->gpe_pp;
                        if (pp != NULL) {
                                pp->private = NULL;
                                g_wither_provider(pp, ENXIO);
                        }
                        LIST_REMOVE(entry, gpe_entry);
                        g_free(entry);
                }
        }

        error = G_PART_DESTROY(table, gpp);
        if (error) {
                gctl_error(req, "%d", error);
                return (error);
        }

        gp->softc = kobj_create((kobj_class_t)&g_part_null_scheme, M_GEOM,
            M_WAITOK);
        null = gp->softc;
        null->gpt_gp = gp;
        null->gpt_scheme = &g_part_null_scheme;
        LIST_INIT(&null->gpt_entry);

        cp = LIST_FIRST(&gp->consumer);
        pp = cp->provider;
        null->gpt_last = pp->mediasize / pp->sectorsize - 1;

        null->gpt_depth = table->gpt_depth;
        null->gpt_opened = table->gpt_opened;
        null->gpt_smhead = table->gpt_smhead;
        null->gpt_smtail = table->gpt_smtail;

        while ((entry = LIST_FIRST(&table->gpt_entry)) != NULL) {
                LIST_REMOVE(entry, gpe_entry);
                g_free(entry);
        }
        kobj_delete((kobj_t)table, M_GEOM);

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                sbuf_printf(sb, "%s destroyed\n", gp->name);
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_modify(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_geom *gp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct sbuf *sb;
        int error;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;

        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_deleted || entry->gpe_internal)
                        continue;
                if (entry->gpe_index == gpp->gpp_index)
                        break;
        }
        if (entry == NULL) {
                gctl_error(req, "%d index '%d'", ENOENT, gpp->gpp_index);
                return (ENOENT);
        }

        error = G_PART_MODIFY(table, entry, gpp);
        if (error) {
                gctl_error(req, "%d", error);
                return (error);
        }

        if (!entry->gpe_created)
                entry->gpe_modified = 1;

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                G_PART_FULLNAME(table, entry, sb, gp->name);
                sbuf_cat(sb, " modified\n");
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_move(struct gctl_req *req, struct g_part_parms *gpp)
{
        gctl_error(req, "%d verb 'move'", ENOSYS);
        return (ENOSYS);
}

static int
g_part_ctl_recover(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_part_table *table;
        struct g_geom *gp;
        struct sbuf *sb;
        int error, recovered;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();
        table = gp->softc;
        error = recovered = 0;

        if (table->gpt_corrupt) {
                error = G_PART_RECOVER(table);
                if (error == 0)
                        error = g_part_check_integrity(table,
                            LIST_FIRST(&gp->consumer));
                if (error) {
                        gctl_error(req, "%d recovering '%s' failed",
                            error, gp->name);
                        return (error);
                }
                recovered = 1;
        }
        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                if (recovered)
                        sbuf_printf(sb, "%s recovered\n", gp->name);
                else
                        sbuf_printf(sb, "%s recovering is not needed\n",
                            gp->name);
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_resize(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_entry *pe, *entry;
        struct g_part_table *table;
        struct sbuf *sb;
        quad_t end;
        int error;
        off_t mediasize;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();
        table = gp->softc;

        /* check gpp_index */
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (entry->gpe_deleted || entry->gpe_internal)
                        continue;
                if (entry->gpe_index == gpp->gpp_index)
                        break;
        }
        if (entry == NULL) {
                gctl_error(req, "%d index '%d'", ENOENT, gpp->gpp_index);
                return (ENOENT);
        }

        /* check gpp_size */
        end = entry->gpe_start + gpp->gpp_size - 1;
        if (gpp->gpp_size < 1 || end > table->gpt_last) {
                gctl_error(req, "%d size '%jd'", EINVAL,
                    (intmax_t)gpp->gpp_size);
                return (EINVAL);
        }

        LIST_FOREACH(pe, &table->gpt_entry, gpe_entry) {
                if (pe->gpe_deleted || pe->gpe_internal || pe == entry)
                        continue;
                if (end >= pe->gpe_start && end <= pe->gpe_end) {
                        gctl_error(req, "%d end '%jd'", ENOSPC,
                            (intmax_t)end);
                        return (ENOSPC);
                }
                if (entry->gpe_start < pe->gpe_start && end > pe->gpe_end) {
                        gctl_error(req, "%d size '%jd'", ENOSPC,
                            (intmax_t)gpp->gpp_size);
                        return (ENOSPC);
                }
        }

        pp = entry->gpe_pp;
        if ((g_debugflags & G_F_FOOTSHOOTING) == 0 &&
            (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)) {
                if (entry->gpe_end - entry->gpe_start + 1 > gpp->gpp_size) {
                        /* Deny shrinking of an opened partition. */
                        gctl_error(req, "%d", EBUSY);
                        return (EBUSY);
                }
        }

        error = G_PART_RESIZE(table, entry, gpp);
        if (error) {
                gctl_error(req, "%d%s", error, error != EBUSY ? "":
                    " resizing will lead to unexpected shrinking"
                    " due to alignment");
                return (error);
        }

        if (!entry->gpe_created)
                entry->gpe_modified = 1;

        /* update mediasize of changed provider */
        mediasize = (entry->gpe_end - entry->gpe_start + 1) *
                pp->sectorsize;
        g_resize_provider(pp, mediasize);

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                G_PART_FULLNAME(table, entry, sb, gp->name);
                sbuf_cat(sb, " resized\n");
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_setunset(struct gctl_req *req, struct g_part_parms *gpp,
    unsigned int set)
{
        struct g_geom *gp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct sbuf *sb;
        int error;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;

        if (gpp->gpp_parms & G_PART_PARM_INDEX) {
                LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                        if (entry->gpe_deleted || entry->gpe_internal)
                                continue;
                        if (entry->gpe_index == gpp->gpp_index)
                                break;
                }
                if (entry == NULL) {
                        gctl_error(req, "%d index '%d'", ENOENT,
                            gpp->gpp_index);
                        return (ENOENT);
                }
        } else
                entry = NULL;

        error = G_PART_SETUNSET(table, entry, gpp->gpp_attrib, set);
        if (error) {
                gctl_error(req, "%d attrib '%s'", error, gpp->gpp_attrib);
                return (error);
        }

        /* Provide feedback if so requested. */
        if (gpp->gpp_parms & G_PART_PARM_OUTPUT) {
                sb = sbuf_new_auto();
                sbuf_printf(sb, "%s %sset on ", gpp->gpp_attrib,
                    (set) ? "" : "un");
                if (entry)
                        G_PART_FULLNAME(table, entry, sb, gp->name);
                else
                        sbuf_cat(sb, gp->name);
                sbuf_cat(sb, "\n");
                sbuf_finish(sb);
                gctl_set_param(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
                sbuf_delete(sb);
        }
        return (0);
}

static int
g_part_ctl_undo(struct gctl_req *req, struct g_part_parms *gpp)
{
        struct g_consumer *cp;
        struct g_provider *pp;
        struct g_geom *gp;
        struct g_part_entry *entry, *tmp;
        struct g_part_table *table;
        int error, reprobe;

        gp = gpp->gpp_geom;
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, gp->name));
        g_topology_assert();

        table = gp->softc;
        if (!table->gpt_opened) {
                gctl_error(req, "%d", EPERM);
                return (EPERM);
        }

        cp = LIST_FIRST(&gp->consumer);
        LIST_FOREACH_SAFE(entry, &table->gpt_entry, gpe_entry, tmp) {
                entry->gpe_modified = 0;
                if (entry->gpe_created) {
                        pp = entry->gpe_pp;
                        if (pp != NULL) {
                                pp->private = NULL;
                                entry->gpe_pp = NULL;
                                g_wither_provider(pp, ENXIO);
                        }
                        entry->gpe_deleted = 1;
                }
                if (entry->gpe_deleted) {
                        LIST_REMOVE(entry, gpe_entry);
                        g_free(entry);
                }
        }

        g_topology_unlock();

        reprobe = (table->gpt_scheme == &g_part_null_scheme ||
            table->gpt_created) ? 1 : 0;

        if (reprobe) {
                LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                        if (entry->gpe_internal)
                                continue;
                        error = EBUSY;
                        goto fail;
                }
                while ((entry = LIST_FIRST(&table->gpt_entry)) != NULL) {
                        LIST_REMOVE(entry, gpe_entry);
                        g_free(entry);
                }
                error = g_part_probe(gp, cp, table->gpt_depth);
                if (error) {
                        g_topology_lock();
                        g_access(cp, -1, -1, -1);
                        g_part_wither(gp, error);
                        return (0);
                }
                table = gp->softc;

                /*
                 * Synthesize a disk geometry. Some partitioning schemes
                 * depend on it and since some file systems need it even
                 * when the partition scheme doesn't, we do it here in
                 * scheme-independent code.
                 */
                pp = cp->provider;
                g_part_geometry(table, cp, pp->mediasize / pp->sectorsize);
        }

        error = G_PART_READ(table, cp);
        if (error)
                goto fail;
        error = g_part_check_integrity(table, cp);
        if (error)
                goto fail;

        g_topology_lock();
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (!entry->gpe_internal)
                        g_part_new_provider(gp, table, entry);
        }

        table->gpt_opened = 0;
        g_access(cp, -1, -1, -1);
        return (0);

fail:
        g_topology_lock();
        gctl_error(req, "%d", error);
        return (error);
}

static void
g_part_wither(struct g_geom *gp, int error)
{
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct g_provider *pp;

        table = gp->softc;
        if (table != NULL) {
                gp->softc = NULL;
                while ((entry = LIST_FIRST(&table->gpt_entry)) != NULL) {
                        LIST_REMOVE(entry, gpe_entry);
                        pp = entry->gpe_pp;
                        entry->gpe_pp = NULL;
                        if (pp != NULL) {
                                pp->private = NULL;
                                g_wither_provider(pp, error);
                        }
                        g_free(entry);
                }
                G_PART_DESTROY(table, NULL);
                kobj_delete((kobj_t)table, M_GEOM);
        }
        g_wither_geom(gp, error);
}

/*
 * Class methods.
 */

static void
g_part_ctlreq(struct gctl_req *req, struct g_class *mp, const char *verb)
{
        struct g_part_parms gpp;
        struct g_part_table *table;
        struct gctl_req_arg *ap;
        enum g_part_ctl ctlreq;
        unsigned int i, mparms, oparms, parm;
        int auto_commit, close_on_error;
        int error, modifies;

        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, verb));
        g_topology_assert();

        ctlreq = G_PART_CTL_NONE;
        modifies = 1;
        mparms = 0;
        oparms = G_PART_PARM_FLAGS | G_PART_PARM_OUTPUT | G_PART_PARM_VERSION;
        switch (*verb) {
        case 'a':
                if (!strcmp(verb, "add")) {
                        ctlreq = G_PART_CTL_ADD;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_SIZE |
                            G_PART_PARM_START | G_PART_PARM_TYPE;
                        oparms |= G_PART_PARM_INDEX | G_PART_PARM_LABEL;
                }
                break;
        case 'b':
                if (!strcmp(verb, "bootcode")) {
                        ctlreq = G_PART_CTL_BOOTCODE;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_BOOTCODE;
                        oparms |= G_PART_PARM_SKIP_DSN;
                }
                break;
        case 'c':
                if (!strcmp(verb, "commit")) {
                        ctlreq = G_PART_CTL_COMMIT;
                        mparms |= G_PART_PARM_GEOM;
                        modifies = 0;
                } else if (!strcmp(verb, "create")) {
                        ctlreq = G_PART_CTL_CREATE;
                        mparms |= G_PART_PARM_PROVIDER | G_PART_PARM_SCHEME;
                        oparms |= G_PART_PARM_ENTRIES;
                }
                break;
        case 'd':
                if (!strcmp(verb, "delete")) {
                        ctlreq = G_PART_CTL_DELETE;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_INDEX;
                } else if (!strcmp(verb, "destroy")) {
                        ctlreq = G_PART_CTL_DESTROY;
                        mparms |= G_PART_PARM_GEOM;
                        oparms |= G_PART_PARM_FORCE;
                }
                break;
        case 'm':
                if (!strcmp(verb, "modify")) {
                        ctlreq = G_PART_CTL_MODIFY;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_INDEX;
                        oparms |= G_PART_PARM_LABEL | G_PART_PARM_TYPE;
                } else if (!strcmp(verb, "move")) {
                        ctlreq = G_PART_CTL_MOVE;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_INDEX;
                }
                break;
        case 'r':
                if (!strcmp(verb, "recover")) {
                        ctlreq = G_PART_CTL_RECOVER;
                        mparms |= G_PART_PARM_GEOM;
                } else if (!strcmp(verb, "resize")) {
                        ctlreq = G_PART_CTL_RESIZE;
                        mparms |= G_PART_PARM_GEOM | G_PART_PARM_INDEX |
                            G_PART_PARM_SIZE;
                }
                break;
        case 's':
                if (!strcmp(verb, "set")) {
                        ctlreq = G_PART_CTL_SET;
                        mparms |= G_PART_PARM_ATTRIB | G_PART_PARM_GEOM;
                        oparms |= G_PART_PARM_INDEX;
                }
                break;
        case 'u':
                if (!strcmp(verb, "undo")) {
                        ctlreq = G_PART_CTL_UNDO;
                        mparms |= G_PART_PARM_GEOM;
                        modifies = 0;
                } else if (!strcmp(verb, "unset")) {
                        ctlreq = G_PART_CTL_UNSET;
                        mparms |= G_PART_PARM_ATTRIB | G_PART_PARM_GEOM;
                        oparms |= G_PART_PARM_INDEX;
                }
                break;
        }
        if (ctlreq == G_PART_CTL_NONE) {
                gctl_error(req, "%d verb '%s'", EINVAL, verb);
                return;
        }

        bzero(&gpp, sizeof(gpp));
        for (i = 0; i < req->narg; i++) {
                ap = &req->arg[i];
                parm = 0;
                switch (ap->name[0]) {
                case 'a':
                        if (!strcmp(ap->name, "arg0")) {
                                parm = mparms &
                                    (G_PART_PARM_GEOM | G_PART_PARM_PROVIDER);
                        }
                        if (!strcmp(ap->name, "attrib"))
                                parm = G_PART_PARM_ATTRIB;
                        break;
                case 'b':
                        if (!strcmp(ap->name, "bootcode"))
                                parm = G_PART_PARM_BOOTCODE;
                        break;
                case 'c':
                        if (!strcmp(ap->name, "class"))
                                continue;
                        break;
                case 'e':
                        if (!strcmp(ap->name, "entries"))
                                parm = G_PART_PARM_ENTRIES;
                        break;
                case 'f':
                        if (!strcmp(ap->name, "flags"))
                                parm = G_PART_PARM_FLAGS;
                        else if (!strcmp(ap->name, "force"))
                                parm = G_PART_PARM_FORCE;
                        break;
                case 'i':
                        if (!strcmp(ap->name, "index"))
                                parm = G_PART_PARM_INDEX;
                        break;
                case 'l':
                        if (!strcmp(ap->name, "label"))
                                parm = G_PART_PARM_LABEL;
                        break;
                case 'o':
                        if (!strcmp(ap->name, "output"))
                                parm = G_PART_PARM_OUTPUT;
                        break;
                case 's':
                        if (!strcmp(ap->name, "scheme"))
                                parm = G_PART_PARM_SCHEME;
                        else if (!strcmp(ap->name, "size"))
                                parm = G_PART_PARM_SIZE;
                        else if (!strcmp(ap->name, "start"))
                                parm = G_PART_PARM_START;
                        else if (!strcmp(ap->name, "skip_dsn"))
                                parm = G_PART_PARM_SKIP_DSN;
                        break;
                case 't':
                        if (!strcmp(ap->name, "type"))
                                parm = G_PART_PARM_TYPE;
                        break;
                case 'v':
                        if (!strcmp(ap->name, "verb"))
                                continue;
                        else if (!strcmp(ap->name, "version"))
                                parm = G_PART_PARM_VERSION;
                        break;
                }
                if ((parm & (mparms | oparms)) == 0) {
                        gctl_error(req, "%d param '%s'", EINVAL, ap->name);
                        return;
                }
                switch (parm) {
                case G_PART_PARM_ATTRIB:
                        error = g_part_parm_str(req, ap->name,
                            &gpp.gpp_attrib);
                        break;
                case G_PART_PARM_BOOTCODE:
                        error = g_part_parm_bootcode(req, ap->name,
                            &gpp.gpp_codeptr, &gpp.gpp_codesize);
                        break;
                case G_PART_PARM_ENTRIES:
                        error = g_part_parm_intmax(req, ap->name,
                            &gpp.gpp_entries);
                        break;
                case G_PART_PARM_FLAGS:
                        error = g_part_parm_str(req, ap->name, &gpp.gpp_flags);
                        break;
                case G_PART_PARM_FORCE:
                        error = g_part_parm_uint32(req, ap->name,
                            &gpp.gpp_force);
                        break;
                case G_PART_PARM_GEOM:
                        error = g_part_parm_geom(req, ap->name, &gpp.gpp_geom);
                        break;
                case G_PART_PARM_INDEX:
                        error = g_part_parm_intmax(req, ap->name,
                            &gpp.gpp_index);
                        break;
                case G_PART_PARM_LABEL:
                        error = g_part_parm_str(req, ap->name, &gpp.gpp_label);
                        break;
                case G_PART_PARM_OUTPUT:
                        error = 0;      /* Write-only parameter */
                        break;
                case G_PART_PARM_PROVIDER:
                        error = g_part_parm_provider(req, ap->name,
                            &gpp.gpp_provider);
                        break;
                case G_PART_PARM_SCHEME:
                        error = g_part_parm_scheme(req, ap->name,
                            &gpp.gpp_scheme);
                        break;
                case G_PART_PARM_SIZE:
                        error = g_part_parm_quad(req, ap->name, &gpp.gpp_size);
                        break;
                case G_PART_PARM_SKIP_DSN:
                        error = g_part_parm_uint32(req, ap->name,
                            &gpp.gpp_skip_dsn);
                        break;
                case G_PART_PARM_START:
                        error = g_part_parm_quad(req, ap->name,
                            &gpp.gpp_start);
                        break;
                case G_PART_PARM_TYPE:
                        error = g_part_parm_str(req, ap->name, &gpp.gpp_type);
                        break;
                case G_PART_PARM_VERSION:
                        error = g_part_parm_uint32(req, ap->name,
                            &gpp.gpp_version);
                        break;
                default:
                        error = EDOOFUS;
                        gctl_error(req, "%d %s", error, ap->name);
                        break;
                }
                if (error != 0) {
                        if (error == ENOATTR) {
                                gctl_error(req, "%d param '%s'", error,
                                    ap->name);
                        }
                        return;
                }
                gpp.gpp_parms |= parm;
        }
        if ((gpp.gpp_parms & mparms) != mparms) {
                parm = mparms - (gpp.gpp_parms & mparms);
                gctl_error(req, "%d param '%x'", ENOATTR, parm);
                return;
        }

        /* Obtain permissions if possible/necessary. */
        close_on_error = 0;
        table = NULL;
        if (modifies && (gpp.gpp_parms & G_PART_PARM_GEOM)) {
                table = gpp.gpp_geom->softc;
                if (table != NULL && table->gpt_corrupt &&
                    ctlreq != G_PART_CTL_DESTROY &&
                    ctlreq != G_PART_CTL_RECOVER &&
                    geom_part_check_integrity) {
                        gctl_error(req, "%d table '%s' is corrupt",
                            EPERM, gpp.gpp_geom->name);
                        return;
                }
                if (table != NULL && !table->gpt_opened) {
                        error = g_access(LIST_FIRST(&gpp.gpp_geom->consumer),
                            1, 1, 1);
                        if (error) {
                                gctl_error(req, "%d geom '%s'", error,
                                    gpp.gpp_geom->name);
                                return;
                        }
                        table->gpt_opened = 1;
                        close_on_error = 1;
                }
        }

        /* Allow the scheme to check or modify the parameters. */
        if (table != NULL) {
                error = G_PART_PRECHECK(table, ctlreq, &gpp);
                if (error) {
                        gctl_error(req, "%d pre-check failed", error);
                        goto out;
                }
        } else
                error = EDOOFUS;        /* Prevent bogus uninit. warning. */

        switch (ctlreq) {
        case G_PART_CTL_NONE:
                panic("%s", __func__);
        case G_PART_CTL_ADD:
                error = g_part_ctl_add(req, &gpp);
                break;
        case G_PART_CTL_BOOTCODE:
                error = g_part_ctl_bootcode(req, &gpp);
                break;
        case G_PART_CTL_COMMIT:
                error = g_part_ctl_commit(req, &gpp);
                break;
        case G_PART_CTL_CREATE:
                error = g_part_ctl_create(req, &gpp);
                break;
        case G_PART_CTL_DELETE:
                error = g_part_ctl_delete(req, &gpp);
                break;
        case G_PART_CTL_DESTROY:
                error = g_part_ctl_destroy(req, &gpp);
                break;
        case G_PART_CTL_MODIFY:
                error = g_part_ctl_modify(req, &gpp);
                break;
        case G_PART_CTL_MOVE:
                error = g_part_ctl_move(req, &gpp);
                break;
        case G_PART_CTL_RECOVER:
                error = g_part_ctl_recover(req, &gpp);
                break;
        case G_PART_CTL_RESIZE:
                error = g_part_ctl_resize(req, &gpp);
                break;
        case G_PART_CTL_SET:
                error = g_part_ctl_setunset(req, &gpp, 1);
                break;
        case G_PART_CTL_UNDO:
                error = g_part_ctl_undo(req, &gpp);
                break;
        case G_PART_CTL_UNSET:
                error = g_part_ctl_setunset(req, &gpp, 0);
                break;
        }

        /* Implement automatic commit. */
        if (!error) {
                auto_commit = (modifies &&
                    (gpp.gpp_parms & G_PART_PARM_FLAGS) &&
                    strchr(gpp.gpp_flags, 'C') != NULL) ? 1 : 0;
                if (auto_commit) {
                        KASSERT(gpp.gpp_parms & G_PART_PARM_GEOM, ("%s",
                            __func__));
                        error = g_part_ctl_commit(req, &gpp);
                }
        }

 out:
        if (error && close_on_error) {
                g_access(LIST_FIRST(&gpp.gpp_geom->consumer), -1, -1, -1);
                table->gpt_opened = 0;
        }
}

static int
g_part_destroy_geom(struct gctl_req *req, struct g_class *mp,
    struct g_geom *gp)
{

        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, gp->name));
        g_topology_assert();

        g_part_wither(gp, EINVAL);
        return (0);
}

static struct g_geom *
g_part_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct root_hold_token *rht;
        int attr, depth;
        int error;

        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, pp->name));
        g_topology_assert();

        /* Skip providers that are already open for writing. */
        if (pp->acw > 0)
                return (NULL);

        /*
         * Create a GEOM with consumer and hook it up to the provider.
         * With that we become part of the topology. Obtain read access
         * to the provider.
         */
        gp = g_new_geom(mp, pp->name);
        cp = g_new_consumer(gp);
        cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
        error = g_attach(cp, pp);
        if (error == 0)
                error = g_access(cp, 1, 0, 0);
        if (error != 0) {
                if (cp->provider)
                        g_detach(cp);
                g_destroy_consumer(cp);
                g_destroy_geom(gp);
                return (NULL);
        }

        rht = root_mount_hold(mp->name);
        g_topology_unlock();

        /*
         * Short-circuit the whole probing galore when there's no
         * media present.
         */
        if (pp->mediasize == 0 || pp->sectorsize == 0) {
                error = ENODEV;
                goto fail;
        }

        /* Make sure we can nest and if so, determine our depth. */
        error = g_getattr("PART::isleaf", cp, &attr);
        if (!error && attr) {
                error = ENODEV;
                goto fail;
        }
        error = g_getattr("PART::depth", cp, &attr);
        depth = (!error) ? attr + 1 : 0;

        error = g_part_probe(gp, cp, depth);
        if (error)
                goto fail;

        table = gp->softc;

        /*
         * Synthesize a disk geometry. Some partitioning schemes
         * depend on it and since some file systems need it even
         * when the partition scheme doesn't, we do it here in
         * scheme-independent code.
         */
        g_part_geometry(table, cp, pp->mediasize / pp->sectorsize);

        error = G_PART_READ(table, cp);
        if (error)
                goto fail;
        error = g_part_check_integrity(table, cp);
        if (error)
                goto fail;

        g_topology_lock();
        LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
                if (!entry->gpe_internal)
                        g_part_new_provider(gp, table, entry);
        }

        root_mount_rel(rht);
        g_access(cp, -1, 0, 0);
        return (gp);

 fail:
        g_topology_lock();
        root_mount_rel(rht);
        g_access(cp, -1, 0, 0);
        g_detach(cp);
        g_destroy_consumer(cp);
        g_destroy_geom(gp);
        return (NULL);
}

/*
 * Geom methods.
 */

static int
g_part_access(struct g_provider *pp, int dr, int dw, int de)
{
        struct g_consumer *cp;

        G_PART_TRACE((G_T_ACCESS, "%s(%s,%d,%d,%d)", __func__, pp->name, dr,
            dw, de));

        cp = LIST_FIRST(&pp->geom->consumer);

        /* We always gain write-exclusive access. */
        return (g_access(cp, dr, dw, dw + de));
}

static void
g_part_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
    struct g_consumer *cp, struct g_provider *pp)
{
        char buf[64];
        struct g_part_entry *entry;
        struct g_part_table *table;

        KASSERT(sb != NULL && gp != NULL, ("%s", __func__));
        table = gp->softc;

        if (indent == NULL) {
                KASSERT(cp == NULL && pp != NULL, ("%s", __func__));
                entry = pp->private;
                if (entry == NULL)
                        return;
                sbuf_printf(sb, " i %u o %ju ty %s", entry->gpe_index,
                    (uintmax_t)entry->gpe_offset,
                    G_PART_TYPE(table, entry, buf, sizeof(buf)));
                /*
                 * libdisk compatibility quirk - the scheme dumps the
                 * slicer name and partition type in a way that is
                 * compatible with libdisk. When libdisk is not used
                 * anymore, this should go away.
                 */
                G_PART_DUMPCONF(table, entry, sb, indent);
        } else if (cp != NULL) {        /* Consumer configuration. */
                KASSERT(pp == NULL, ("%s", __func__));
                /* none */
        } else if (pp != NULL) {        /* Provider configuration. */
                entry = pp->private;
                if (entry == NULL)
                        return;
                sbuf_printf(sb, "%s<start>%ju</start>\n", indent,
                    (uintmax_t)entry->gpe_start);
                sbuf_printf(sb, "%s<end>%ju</end>\n", indent,
                    (uintmax_t)entry->gpe_end);
                sbuf_printf(sb, "%s<index>%u</index>\n", indent,
                    entry->gpe_index);
                sbuf_printf(sb, "%s<type>%s</type>\n", indent,
                    G_PART_TYPE(table, entry, buf, sizeof(buf)));
                sbuf_printf(sb, "%s<offset>%ju</offset>\n", indent,
                    (uintmax_t)entry->gpe_offset);
                sbuf_printf(sb, "%s<length>%ju</length>\n", indent,
                    (uintmax_t)pp->mediasize);
                G_PART_DUMPCONF(table, entry, sb, indent);
        } else {                        /* Geom configuration. */
                sbuf_printf(sb, "%s<scheme>%s</scheme>\n", indent,
                    table->gpt_scheme->name);
                sbuf_printf(sb, "%s<entries>%u</entries>\n", indent,
                    table->gpt_entries);
                sbuf_printf(sb, "%s<first>%ju</first>\n", indent,
                    (uintmax_t)table->gpt_first);
                sbuf_printf(sb, "%s<last>%ju</last>\n", indent,
                    (uintmax_t)table->gpt_last);
                sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n", indent,
                    table->gpt_sectors);
                sbuf_printf(sb, "%s<fwheads>%u</fwheads>\n", indent,
                    table->gpt_heads);
                sbuf_printf(sb, "%s<state>%s</state>\n", indent,
                    table->gpt_corrupt ? "CORRUPT": "OK");
                sbuf_printf(sb, "%s<modified>%s</modified>\n", indent,
                    table->gpt_opened ? "true": "false");
                G_PART_DUMPCONF(table, NULL, sb, indent);
        }
}

/*-
 * This start routine is only called for non-trivial requests, all the
 * trivial ones are handled autonomously by the slice code.
 * For requests we handle here, we must call the g_io_deliver() on the
 * bio, and return non-zero to indicate to the slice code that we did so.
 * This code executes in the "DOWN" I/O path, this means:
 *    * No sleeping.
 *    * Don't grab the topology lock.
 *    * Don't call biowait, g_getattr(), g_setattr() or g_read_data()
 */
static int
g_part_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
{
        struct g_part_table *table;

        table = pp->geom->softc;
        return G_PART_IOCTL(table, pp, cmd, data, fflag, td);
}

static void
g_part_resize(struct g_consumer *cp)
{
        struct g_part_table *table;

        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name));
        g_topology_assert();

        if (auto_resize == 0)
                return;

        table = cp->geom->softc;
        if (table->gpt_opened == 0) {
                if (g_access(cp, 1, 1, 1) != 0)
                        return;
                table->gpt_opened = 1;
        }
        if (G_PART_RESIZE(table, NULL, NULL) == 0)
                printf("GEOM_PART: %s was automatically resized.\n"
                    "  Use `gpart commit %s` to save changes or "
                    "`gpart undo %s` to revert them.\n", cp->geom->name,
                    cp->geom->name, cp->geom->name);
        if (g_part_check_integrity(table, cp) != 0) {
                g_access(cp, -1, -1, -1);
                table->gpt_opened = 0;
                g_part_wither(table->gpt_gp, ENXIO);
        }
}

static void
g_part_orphan(struct g_consumer *cp)
{
        struct g_provider *pp;
        struct g_part_table *table;

        pp = cp->provider;
        KASSERT(pp != NULL, ("%s", __func__));
        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, pp->name));
        g_topology_assert();

        KASSERT(pp->error != 0, ("%s", __func__));
        table = cp->geom->softc;
        if (table != NULL && table->gpt_opened)
                g_access(cp, -1, -1, -1);
        g_part_wither(cp->geom, pp->error);
}

static void
g_part_spoiled(struct g_consumer *cp)
{

        G_PART_TRACE((G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name));
        g_topology_assert();

        cp->flags |= G_CF_ORPHAN;
        g_part_wither(cp->geom, ENXIO);
}

static void
g_part_start(struct bio *bp)
{
        struct bio *bp2;
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_part_entry *entry;
        struct g_part_table *table;
        struct g_kerneldump *gkd;
        struct g_provider *pp;
        void (*done_func)(struct bio *) = g_std_done;
        char buf[64];

        biotrack(bp, __func__);

        pp = bp->bio_to;
        gp = pp->geom;
        table = gp->softc;
        cp = LIST_FIRST(&gp->consumer);

        G_PART_TRACE((G_T_BIO, "%s: cmd=%d, provider=%s", __func__, bp->bio_cmd,
            pp->name));

        entry = pp->private;
        if (entry == NULL) {
                g_io_deliver(bp, ENXIO);
                return;
        }

        switch(bp->bio_cmd) {
        case BIO_DELETE:
        case BIO_READ:
        case BIO_WRITE:
                if (bp->bio_offset >= pp->mediasize) {
                        g_io_deliver(bp, EIO);
                        return;
                }
                bp2 = g_clone_bio(bp);
                if (bp2 == NULL) {
                        g_io_deliver(bp, ENOMEM);
                        return;
                }
                if (bp2->bio_offset + bp2->bio_length > pp->mediasize)
                        bp2->bio_length = pp->mediasize - bp2->bio_offset;
                bp2->bio_done = g_std_done;
                bp2->bio_offset += entry->gpe_offset;
                g_io_request(bp2, cp);
                return;
        case BIO_SPEEDUP:
        case BIO_FLUSH:
                break;
        case BIO_GETATTR:
                if (g_handleattr_int(bp, "GEOM::fwheads", table->gpt_heads))
                        return;
                if (g_handleattr_int(bp, "GEOM::fwsectors", table->gpt_sectors))
                        return;
                /*
                 * allow_nesting overrides "isleaf" to false _unless_ the
                 * provider offset is zero, since otherwise we would recurse.
                 */
                if (g_handleattr_int(bp, "PART::isleaf",
                        table->gpt_isleaf &&
                        (allow_nesting == 0 || entry->gpe_offset == 0)))
                        return;
                if (g_handleattr_int(bp, "PART::depth", table->gpt_depth))
                        return;
                if (g_handleattr_str(bp, "PART::scheme",
                    table->gpt_scheme->name))
                        return;
                if (g_handleattr_str(bp, "PART::type",
                    G_PART_TYPE(table, entry, buf, sizeof(buf))))
                        return;
                if (!strcmp("GEOM::physpath", bp->bio_attribute)) {
                        done_func = g_part_get_physpath_done;
                        break;
                }
                if (!strcmp("GEOM::kerneldump", bp->bio_attribute)) {
                        /*
                         * Check that the partition is suitable for kernel
                         * dumps. Typically only swap partitions should be
                         * used. If the request comes from the nested scheme
                         * we allow dumping there as well.
                         */
                        if ((bp->bio_from == NULL ||
                            bp->bio_from->geom->class != &g_part_class) &&
                            G_PART_DUMPTO(table, entry) == 0) {
                                g_io_deliver(bp, ENODEV);
                                printf("GEOM_PART: Partition '%s' not suitable"
                                    " for kernel dumps (wrong type?)\n",
                                    pp->name);
                                return;
                        }
                        gkd = (struct g_kerneldump *)bp->bio_data;
                        if (gkd->offset >= pp->mediasize) {
                                g_io_deliver(bp, EIO);
                                return;
                        }
                        if (gkd->offset + gkd->length > pp->mediasize)
                                gkd->length = pp->mediasize - gkd->offset;
                        gkd->offset += entry->gpe_offset;
                }
                break;
        default:
                g_io_deliver(bp, EOPNOTSUPP);
                return;
        }

        bp2 = g_clone_bio(bp);
        if (bp2 == NULL) {
                g_io_deliver(bp, ENOMEM);
                return;
        }
        bp2->bio_done = done_func;
        g_io_request(bp2, cp);
}

static void
g_part_init(struct g_class *mp)
{

        TAILQ_INSERT_HEAD(&g_part_schemes, &g_part_null_scheme, scheme_list);
}

static void
g_part_fini(struct g_class *mp)
{

        TAILQ_REMOVE(&g_part_schemes, &g_part_null_scheme, scheme_list);
}

static void
g_part_unload_event(void *arg, int flag)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_provider *pp;
        struct g_part_scheme *scheme;
        struct g_part_table *table;
        uintptr_t *xchg;
        int acc, error;

        if (flag == EV_CANCEL)
                return;

        xchg = arg;
        error = 0;
        scheme = (void *)(*xchg);

        g_topology_assert();

        LIST_FOREACH(gp, &g_part_class.geom, geom) {
                table = gp->softc;
                if (table->gpt_scheme != scheme)
                        continue;

                acc = 0;
                LIST_FOREACH(pp, &gp->provider, provider)
                        acc += pp->acr + pp->acw + pp->ace;
                LIST_FOREACH(cp, &gp->consumer, consumer)
                        acc += cp->acr + cp->acw + cp->ace;

                if (!acc)
                        g_part_wither(gp, ENOSYS);
                else
                        error = EBUSY;
        }

        if (!error)
                TAILQ_REMOVE(&g_part_schemes, scheme, scheme_list);

        *xchg = error;
}

int
g_part_modevent(module_t mod, int type, struct g_part_scheme *scheme)
{
        struct g_part_scheme *iter;
        uintptr_t arg;
        int error;

        error = 0;
        switch (type) {
        case MOD_LOAD:
                TAILQ_FOREACH(iter, &g_part_schemes, scheme_list) {
                        if (scheme == iter) {
                                printf("GEOM_PART: scheme %s is already "
                                    "registered!\n", scheme->name);
                                break;
                        }
                }
                if (iter == NULL) {
                        TAILQ_INSERT_TAIL(&g_part_schemes, scheme,
                            scheme_list);
                        g_retaste(&g_part_class);
                }
                break;
        case MOD_UNLOAD:
                arg = (uintptr_t)scheme;
                error = g_waitfor_event(g_part_unload_event, &arg, M_WAITOK,
                    NULL);
                if (error == 0)
                        error = arg;
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }

        return (error);
}