drop net-snmp dep

[unleashed.git] / kernel / fs / autofs / auto_vfsops.c

/*
 * 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 (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2011 Bayard G. Bell. All rights reserved.
 * Copyright (c) 2017 by Delphix. All rights reserved.
 */

#include <sys/param.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/disp.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/uio.h>
#include <sys/kmem.h>
#include <sys/cred.h>
#include <sys/statvfs.h>
#include <sys/mount.h>
#include <sys/tiuser.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/pathname.h>
#include <rpc/types.h>
#include <rpc/auth.h>
#include <rpc/clnt.h>
#include <sys/fs_subr.h>
#include <sys/fs/autofs.h>
#include <sys/modctl.h>
#include <sys/mntent.h>
#include <sys/policy.h>
#include <sys/zone.h>

static int autofs_init(int, char *);

static major_t autofs_major;
static minor_t autofs_minor;

kmutex_t autofs_minor_lock;
zone_key_t autofs_key;

static mntopts_t auto_mntopts;

/*
 * The AUTOFS system call.
 */
static struct sysent autofssysent = {
        2,
        SE_32RVAL1 | SE_ARGC | SE_NOUNLOAD,
        autofssys
};

static struct modlsys modlsys = {
        &mod_syscallops,
        "AUTOFS syscall",
        &autofssysent
};

#ifdef  _SYSCALL32_IMPL
static struct modlsys  modlsys32 = {
        &mod_syscallops32,
        "AUTOFS syscall (32-bit)",
        &autofssysent
};
#endif  /* _SYSCALL32_IMPL */

static vfsdef_t vfw = {
        VFSDEF_VERSION,
        "autofs",
        autofs_init,
        VSW_HASPROTO|VSW_CANRWRO|VSW_CANREMOUNT|VSW_STATS|VSW_ZMOUNT,
        &auto_mntopts
};

/*
 * Module linkage information for the kernel.
 */
static struct modlfs modlfs = {
        &mod_fsops, "filesystem for autofs", &vfw
};

static struct modlinkage modlinkage = {
        MODREV_1,
        &modlfs,
        &modlsys,
#ifdef  _SYSCALL32_IMPL
        &modlsys32,
#endif
        NULL
};

/*
 * This is the module initialization routine.
 */
int
_init(void)
{
        return (mod_install(&modlinkage));
}

int
_fini(void)
{
        /*
         * Don't allow the autofs module to be unloaded for now.
         */
        return (EBUSY);
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&modlinkage, modinfop));
}

static int autofs_fstype;

/*
 * autofs VFS operations
 */
static int auto_mount(vfs_t *, vnode_t *, struct mounta *, cred_t *);
static int auto_unmount(vfs_t *, int, cred_t *);
static int auto_root(vfs_t *, vnode_t **);
static int auto_statvfs(vfs_t *, struct statvfs64 *);

/*
 * Auto Mount options table
 */

static char *direct_cancel[] = { MNTOPT_INDIRECT, NULL };
static char *indirect_cancel[] = { MNTOPT_DIRECT, NULL };
static char *browse_cancel[] = { MNTOPT_NOBROWSE, NULL };
static char *nobrowse_cancel[] = { MNTOPT_BROWSE, NULL };

static mntopt_t mntopts[] = {
/*
 *      option name             cancel options  default arg     flags
 */
        { MNTOPT_DIRECT,        direct_cancel,  NULL,           0,
                NULL },
        { MNTOPT_INDIRECT,      indirect_cancel, NULL,          0,
                NULL },
        { MNTOPT_IGNORE,        NULL,           NULL,
                MO_DEFAULT|MO_TAG,      NULL },
        { "nest",               NULL,           NULL,           MO_TAG,
                NULL },
        { MNTOPT_BROWSE,        browse_cancel,  NULL,           MO_TAG,
                NULL },
        { MNTOPT_NOBROWSE,      nobrowse_cancel, NULL,          MO_TAG,
                NULL },
        { MNTOPT_RESTRICT,      NULL,           NULL,           MO_TAG,
                NULL },
};

static mntopts_t auto_mntopts = {
        sizeof (mntopts) / sizeof (mntopt_t),
        mntopts
};

/*ARGSUSED*/
static void
autofs_zone_destructor(zoneid_t zoneid, void *arg)
{
        struct autofs_globals *fngp = arg;
        vnode_t *vp;

        if (fngp == NULL)
                return;
        ASSERT(fngp->fng_fnnode_count == 1);
        ASSERT(fngp->fng_unmount_threads == 0);

        if (fngp->fng_autofs_daemon_dh != NULL)
                door_ki_rele(fngp->fng_autofs_daemon_dh);
        /*
         * vn_alloc() initialized the rootnode with a count of 1; we need to
         * make this 0 to placate auto_freefnnode().
         */
        vp = fntovn(fngp->fng_rootfnnodep);
        mutex_enter(&vp->v_lock);
        ASSERT(vp->v_count == 1);
        VN_RELE_LOCKED(vp);
        mutex_exit(&vp->v_lock);
        auto_freefnnode(fngp->fng_rootfnnodep);
        mutex_destroy(&fngp->fng_unmount_threads_lock);
        kmem_free(fngp, sizeof (*fngp));
}

/*
 * rootfnnodep is allocated here.  Its sole purpose is to provide
 * read/write locking for top level fnnodes.  This object is
 * persistent and will not be deallocated until the zone is destroyed.
 *
 * The current zone is implied as the zone of interest, since we will be
 * calling zthread_create() which must be called from the correct zone.
 */
struct autofs_globals *
autofs_zone_init(void)
{
        char rootname[sizeof ("root_fnnode_zone_") + ZONEID_WIDTH];
        struct autofs_globals *fngp;
        zoneid_t zoneid = getzoneid();

        fngp = kmem_zalloc(sizeof (*fngp), KM_SLEEP);
        (void) snprintf(rootname, sizeof (rootname), "root_fnnode_zone_%d",
            zoneid);
        fngp->fng_rootfnnodep = auto_makefnnode(VNON, NULL, rootname, CRED(),
            fngp);
        /*
         * Don't need to hold fng_rootfnnodep as it's never really used for
         * anything.
         */
        fngp->fng_fnnode_count = 1;
        fngp->fng_printed_not_running_msg = 0;
        fngp->fng_zoneid = zoneid;
        mutex_init(&fngp->fng_unmount_threads_lock, NULL, MUTEX_DEFAULT,
            NULL);
        fngp->fng_unmount_threads = 0;

        mutex_init(&fngp->fng_autofs_daemon_lock, NULL, MUTEX_DEFAULT, NULL);

        /*
         * Start the unmounter thread for this zone.
         */
        (void) zthread_create(NULL, 0, auto_do_unmount, fngp, 0, minclsyspri);
        return (fngp);
}

static const struct vfsops auto_vfsops = {
        .vfs_mount = auto_mount,
        .vfs_unmount = auto_unmount,
        .vfs_root = auto_root,
        .vfs_statvfs = auto_statvfs,
};

int
autofs_init(int fstype, char *name)
{
        int error;

        autofs_fstype = fstype;
        ASSERT(autofs_fstype != 0);
        /*
         * Associate VFS ops vector with this fstype
         */
        error = vfs_setfsops(fstype, &auto_vfsops);
        if (error != 0) {
                cmn_err(CE_WARN, "autofs_init: bad fstype");
                return (error);
        }

        mutex_init(&autofs_minor_lock, NULL, MUTEX_DEFAULT, NULL);
        /*
         * Assign unique major number for all autofs mounts
         */
        if ((autofs_major = getudev()) == (major_t)-1) {
                cmn_err(CE_WARN,
                    "autofs: autofs_init: can't get unique device number");
                mutex_destroy(&autofs_minor_lock);
                return (1);
        }

        /*
         * We'd like to be able to provide a constructor here, but we can't
         * since it wants to zthread_create(), something it can't do in a ZSD
         * constructor.
         */
        zone_key_create(&autofs_key, NULL, NULL, autofs_zone_destructor);

        return (0);
}

static char *restropts[] = {
        RESTRICTED_MNTOPTS
};

/*
 * This routine adds those options to the option string `buf' which are
 * forced by secpolicy_fs_mount.  If the automatic "security" options
 * are set, the option string gets them added if they aren't already
 * there.  We search the string with "strstr" and make sure that
 * the string we find is bracketed with <start|",">MNTOPT<","|"\0">
 *
 * This is one half of the option inheritence algorithm which
 * implements the "restrict" option.  The other half is implemented
 * in automountd; it takes its cue from the options we add here.
 */
static int
autofs_restrict_opts(struct vfs *vfsp, char *buf, size_t maxlen, size_t *curlen)
{
        int i;
        char *p;
        size_t len = *curlen - 1;

        /* Unrestricted */
        if (!vfs_optionisset(vfsp, restropts[0], NULL))
                return (0);

        for (i = 0; i < sizeof (restropts)/sizeof (restropts[0]); i++) {
                size_t olen = strlen(restropts[i]);

                /* Add "restrict" always and the others insofar set */
                if ((i == 0 || vfs_optionisset(vfsp, restropts[i], NULL)) &&
                    ((p = strstr(buf, restropts[i])) == NULL ||
                    !((p == buf || p[-1] == ',') &&
                    (p[olen] == '\0' || p[olen] == ',')))) {

                        if (len + olen + 1 > maxlen)
                                return (-1);

                        if (*buf != '\0')
                                buf[len++] = ',';
                        (void) strcpy(&buf[len], restropts[i]);
                        len += olen;
                }
        }
        *curlen = len + 1;
        return (0);
}

/* ARGSUSED */
static int
auto_mount(vfs_t *vfsp, vnode_t *vp, struct mounta *uap, cred_t *cr)
{
        int error;
        size_t len = 0;
        autofs_args args;
        fninfo_t *fnip = NULL;
        vnode_t *rootvp = NULL;
        fnnode_t *rootfnp = NULL;
        char *data = uap->dataptr;
        char datalen = uap->datalen;
        dev_t autofs_dev;
        char strbuff[MAXPATHLEN + 1];
        vnode_t *kkvp;
        struct autofs_globals *fngp;
        zone_t *zone = curproc->p_zone;

        AUTOFS_DPRINT((4, "auto_mount: vfs %p vp %p\n", (void *)vfsp,
            (void *)vp));

        if ((error = secpolicy_fs_mount(cr, vp, vfsp)) != 0)
                return (EPERM);

        if (zone == global_zone) {
                zone_t *mntzone;

                mntzone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
                ASSERT(mntzone != NULL);
                zone_rele(mntzone);
                if (mntzone != zone) {
                        return (EBUSY);
                }
        }

        /*
         * Stop the mount from going any further if the zone is going away.
         */
        if (zone_status_get(zone) >= ZONE_IS_SHUTTING_DOWN)
                return (EBUSY);

        /*
         * We need a lock to serialize this; minor_lock is as good as any.
         */
        mutex_enter(&autofs_minor_lock);
        if ((fngp = zone_getspecific(autofs_key, zone)) == NULL) {
                fngp = autofs_zone_init();
                (void) zone_setspecific(autofs_key, zone, fngp);
        }
        mutex_exit(&autofs_minor_lock);
        ASSERT(fngp != NULL);

        /*
         * Get arguments
         */
        if (uap->flags & MS_SYSSPACE) {
                if (datalen != sizeof (args))
                        return (EINVAL);
                error = kcopy(data, &args, sizeof (args));
        } else {
                if (get_udatamodel() == DATAMODEL_NATIVE) {
                        if (datalen != sizeof (args))
                                return (EINVAL);
                        error = copyin(data, &args, sizeof (args));
                } else {
                        struct autofs_args32 args32;

                        if (datalen != sizeof (args32))
                                return (EINVAL);
                        error = copyin(data, &args32, sizeof (args32));

                        args.addr.maxlen = args32.addr.maxlen;
                        args.addr.len = args32.addr.len;
                        args.addr.buf = (char *)(uintptr_t)args32.addr.buf;
                        args.path = (char *)(uintptr_t)args32.path;
                        args.opts = (char *)(uintptr_t)args32.opts;
                        args.map = (char *)(uintptr_t)args32.map;
                        args.subdir = (char *)(uintptr_t)args32.subdir;
                        args.key = (char *)(uintptr_t)args32.key;
                        args.mount_to = args32.mount_to;
                        args.rpc_to = args32.rpc_to;
                        args.direct = args32.direct;
                }
        }
        if (error)
                return (EFAULT);

        /*
         * For a remount, only update mount information
         * i.e. default mount options, map name, etc.
         */
        if (uap->flags & MS_REMOUNT) {
                fnip = vfstofni(vfsp);
                if (fnip == NULL)
                        return (EINVAL);

                if (args.direct == 1)
                        fnip->fi_flags |= MF_DIRECT;
                else
                        fnip->fi_flags &= ~MF_DIRECT;
                fnip->fi_mount_to = args.mount_to;
                fnip->fi_rpc_to = args.rpc_to;

                /*
                 * Get default options
                 */
                if (uap->flags & MS_SYSSPACE)
                        error = copystr(args.opts, strbuff, sizeof (strbuff),
                            &len);
                else
                        error = copyinstr(args.opts, strbuff, sizeof (strbuff),
                            &len);
                if (error)
                        return (EFAULT);

                if (autofs_restrict_opts(vfsp, strbuff, sizeof (strbuff), &len)
                    != 0) {
                        return (EFAULT);
                }

                kmem_free(fnip->fi_opts, fnip->fi_optslen);
                fnip->fi_opts = kmem_alloc(len, KM_SLEEP);
                fnip->fi_optslen = (int)len;
                bcopy(strbuff, fnip->fi_opts, len);

                /*
                 * Get context/map name
                 */
                if (uap->flags & MS_SYSSPACE)
                        error = copystr(args.map, strbuff, sizeof (strbuff),
                            &len);
                else
                        error = copyinstr(args.map, strbuff, sizeof (strbuff),
                            &len);
                if (error)
                        return (EFAULT);

                kmem_free(fnip->fi_map, fnip->fi_maplen);
                fnip->fi_map = kmem_alloc(len, KM_SLEEP);
                fnip->fi_maplen = (int)len;
                bcopy(strbuff, fnip->fi_map, len);

                return (0);
        }

        /*
         * Allocate fninfo struct and attach it to vfs
         */
        fnip = kmem_zalloc(sizeof (*fnip), KM_SLEEP);
        fnip->fi_mountvfs = vfsp;

        fnip->fi_mount_to = args.mount_to;
        fnip->fi_rpc_to = args.rpc_to;
        fnip->fi_refcnt = 0;
        vfsp->vfs_bsize = AUTOFS_BLOCKSIZE;
        vfsp->vfs_fstype = autofs_fstype;

        /*
         * Assign a unique device id to the mount
         */
        mutex_enter(&autofs_minor_lock);
        do {
                autofs_minor = (autofs_minor + 1) & L_MAXMIN32;
                autofs_dev = makedevice(autofs_major, autofs_minor);
        } while (vfs_devismounted(autofs_dev));
        mutex_exit(&autofs_minor_lock);
        vfsp->vfs_dev = autofs_dev;
        vfs_make_fsid(&vfsp->vfs_fsid, autofs_dev, autofs_fstype);
        vfsp->vfs_data = (void *)fnip;
        vfsp->vfs_bcount = 0;

        /*
         * Get daemon address
         */
        fnip->fi_addr.len = args.addr.len;
        fnip->fi_addr.maxlen = fnip->fi_addr.len;
        fnip->fi_addr.buf = kmem_alloc(args.addr.len, KM_SLEEP);
        if (uap->flags & MS_SYSSPACE)
                error = kcopy(args.addr.buf, fnip->fi_addr.buf, args.addr.len);
        else
                error = copyin(args.addr.buf, fnip->fi_addr.buf, args.addr.len);
        if (error) {
                error = EFAULT;
                goto errout;
        }

        fnip->fi_zoneid = getzoneid();
        /*
         * Get path for mountpoint
         */
        if (uap->flags & MS_SYSSPACE)
                error = copystr(args.path, strbuff, sizeof (strbuff), &len);
        else
                error = copyinstr(args.path, strbuff, sizeof (strbuff), &len);
        if (error) {
                error = EFAULT;
                goto errout;
        }
        fnip->fi_path = kmem_alloc(len, KM_SLEEP);
        fnip->fi_pathlen = (int)len;
        bcopy(strbuff, fnip->fi_path, len);

        /*
         * Get default options
         */
        if (uap->flags & MS_SYSSPACE)
                error = copystr(args.opts, strbuff, sizeof (strbuff), &len);
        else
                error = copyinstr(args.opts, strbuff, sizeof (strbuff), &len);

        if (error != 0 ||
            autofs_restrict_opts(vfsp, strbuff, sizeof (strbuff), &len) != 0) {
                error = EFAULT;
                goto errout;
        }
        fnip->fi_opts = kmem_alloc(len, KM_SLEEP);
        fnip->fi_optslen = (int)len;
        bcopy(strbuff, fnip->fi_opts, len);

        /*
         * Get context/map name
         */
        if (uap->flags & MS_SYSSPACE)
                error = copystr(args.map, strbuff, sizeof (strbuff), &len);
        else
                error = copyinstr(args.map, strbuff, sizeof (strbuff), &len);
        if (error) {
                error = EFAULT;
                goto errout;
        }
        fnip->fi_map = kmem_alloc(len, KM_SLEEP);
        fnip->fi_maplen = (int)len;
        bcopy(strbuff, fnip->fi_map, len);

        /*
         * Get subdirectory within map
         */
        if (uap->flags & MS_SYSSPACE)
                error = copystr(args.subdir, strbuff, sizeof (strbuff), &len);
        else
                error = copyinstr(args.subdir, strbuff, sizeof (strbuff), &len);
        if (error) {
                error = EFAULT;
                goto errout;
        }
        fnip->fi_subdir = kmem_alloc(len, KM_SLEEP);
        fnip->fi_subdirlen = (int)len;
        bcopy(strbuff, fnip->fi_subdir, len);

        /*
         * Get the key
         */
        if (uap->flags & MS_SYSSPACE)
                error = copystr(args.key, strbuff, sizeof (strbuff), &len);
        else
                error = copyinstr(args.key, strbuff, sizeof (strbuff), &len);
        if (error) {
                error = EFAULT;
                goto errout;
        }
        fnip->fi_key = kmem_alloc(len, KM_SLEEP);
        fnip->fi_keylen = (int)len;
        bcopy(strbuff, fnip->fi_key, len);

        /*
         * Is this a direct mount?
         */
        if (args.direct == 1)
                fnip->fi_flags |= MF_DIRECT;

        /*
         * Setup netconfig.
         * Can I pass in knconf as mount argument? what
         * happens when the daemon gets restarted?
         */
        if ((error = lookupname("/dev/ticotsord", UIO_SYSSPACE, FOLLOW,
            NULLVPP, &kkvp)) != 0) {
                cmn_err(CE_WARN, "autofs: lookupname: %d", error);
                goto errout;
        }

        fnip->fi_knconf.knc_rdev = kkvp->v_rdev;
        fnip->fi_knconf.knc_protofmly = NC_LOOPBACK;
        fnip->fi_knconf.knc_semantics = NC_TPI_COTS_ORD;
        VN_RELE(kkvp);

        /*
         * Make the root vnode
         */
        rootfnp = auto_makefnnode(VDIR, vfsp, fnip->fi_path, cr, fngp);
        if (rootfnp == NULL) {
                error = ENOMEM;
                goto errout;
        }
        rootvp = fntovn(rootfnp);

        rootvp->v_flag |= VROOT;
        rootfnp->fn_mode = AUTOFS_MODE;
        rootfnp->fn_parent = rootfnp;
        /* account for ".." entry */
        rootfnp->fn_linkcnt = rootfnp->fn_size = 1;
        fnip->fi_rootvp = rootvp;

        /*
         * Add to list of top level AUTOFS' if it is being mounted by
         * a user level process.
         */
        if (!(uap->flags & MS_SYSSPACE)) {
                rw_enter(&fngp->fng_rootfnnodep->fn_rwlock, RW_WRITER);
                rootfnp->fn_parent = fngp->fng_rootfnnodep;
                rootfnp->fn_next = fngp->fng_rootfnnodep->fn_dirents;
                fngp->fng_rootfnnodep->fn_dirents = rootfnp;
                rw_exit(&fngp->fng_rootfnnodep->fn_rwlock);
        }

        AUTOFS_DPRINT((5, "auto_mount: vfs %p root %p fnip %p return %d\n",
            (void *)vfsp, (void *)rootvp, (void *)fnip, error));

        return (0);

errout:
        ASSERT(fnip != NULL);
        ASSERT((uap->flags & MS_REMOUNT) == 0);

        if (fnip->fi_addr.buf != NULL)
                kmem_free(fnip->fi_addr.buf, fnip->fi_addr.len);
        if (fnip->fi_path != NULL)
                kmem_free(fnip->fi_path, fnip->fi_pathlen);
        if (fnip->fi_opts != NULL)
                kmem_free(fnip->fi_opts, fnip->fi_optslen);
        if (fnip->fi_map != NULL)
                kmem_free(fnip->fi_map, fnip->fi_maplen);
        if (fnip->fi_subdir != NULL)
                kmem_free(fnip->fi_subdir, fnip->fi_subdirlen);
        if (fnip->fi_key != NULL)
                kmem_free(fnip->fi_key, fnip->fi_keylen);
        kmem_free(fnip, sizeof (*fnip));

        AUTOFS_DPRINT((5, "auto_mount: vfs %p root %p fnip %p return %d\n",
            (void *)vfsp, (void *)rootvp, (void *)fnip, error));

        return (error);
}

/* ARGSUSED */
static int
auto_unmount(vfs_t *vfsp, int flag, cred_t *cr)
{
        fninfo_t *fnip;
        vnode_t *rvp;
        fnnode_t *rfnp, *fnp, *pfnp;
        fnnode_t *myrootfnnodep;

        fnip = vfstofni(vfsp);
        AUTOFS_DPRINT((4, "auto_unmount vfsp %p fnip %p\n", (void *)vfsp,
            (void *)fnip));

        if (secpolicy_fs_unmount(cr, vfsp) != 0)
                return (EPERM);
        /*
         * forced unmount is not supported by this file system
         * and thus, ENOTSUP, is being returned.
         */
        if (flag & MS_FORCE)
                return (ENOTSUP);

        ASSERT(vn_vfswlock_held(vfsp->vfs_vnodecovered));
        rvp = fnip->fi_rootvp;
        rfnp = vntofn(rvp);

        if (rvp->v_count > 1 || rfnp->fn_dirents != NULL)
                return (EBUSY);

        /*
         * The root vnode is on the linked list of root fnnodes only if
         * this was not a trigger node. Since we have no way of knowing,
         * if we don't find it, then we assume it was a trigger node.
         */
        myrootfnnodep = rfnp->fn_globals->fng_rootfnnodep;
        pfnp = NULL;
        rw_enter(&myrootfnnodep->fn_rwlock, RW_WRITER);
        fnp = myrootfnnodep->fn_dirents;
        while (fnp != NULL) {
                if (fnp == rfnp) {
                        /*
                         * A check here is made to see if rvp is busy.  If
                         * so, return EBUSY.  Otherwise proceed with
                         * disconnecting it from the list.
                         */
                        if (rvp->v_count > 1 || rfnp->fn_dirents != NULL) {
                                rw_exit(&myrootfnnodep->fn_rwlock);
                                return (EBUSY);
                        }
                        if (pfnp)
                                pfnp->fn_next = fnp->fn_next;
                        else
                                myrootfnnodep->fn_dirents = fnp->fn_next;
                        fnp->fn_next = NULL;
                        break;
                }
                pfnp = fnp;
                fnp = fnp->fn_next;
        }
        rw_exit(&myrootfnnodep->fn_rwlock);

        ASSERT(rvp->v_count == 1);
        ASSERT(rfnp->fn_size == 1);
        ASSERT(rfnp->fn_linkcnt == 1);
        /*
         * The following drops linkcnt to 0, therefore the disconnect is
         * not attempted when auto_inactive() is called by
         * vn_rele(). This is necessary because we have nothing to get
         * disconnected from since we're the root of the filesystem. As a
         * side effect the node is not freed, therefore I should free the
         * node here.
         *
         * XXX - I really need to think of a better way of doing this.
         */
        rfnp->fn_size--;
        rfnp->fn_linkcnt--;

        /*
         * release of last reference causes node
         * to be freed
         */
        VN_RELE(rvp);
        rfnp->fn_parent = NULL;

        auto_freefnnode(rfnp);

        kmem_free(fnip->fi_addr.buf, fnip->fi_addr.len);
        kmem_free(fnip->fi_path, fnip->fi_pathlen);
        kmem_free(fnip->fi_map, fnip->fi_maplen);
        kmem_free(fnip->fi_subdir, fnip->fi_subdirlen);
        kmem_free(fnip->fi_key, fnip->fi_keylen);
        kmem_free(fnip->fi_opts, fnip->fi_optslen);
        kmem_free(fnip, sizeof (*fnip));
        AUTOFS_DPRINT((5, "auto_unmount: return=0\n"));

        return (0);
}


/*
 * find root of autofs
 */
static int
auto_root(vfs_t *vfsp, vnode_t **vpp)
{
        *vpp = (vnode_t *)vfstofni(vfsp)->fi_rootvp;
        VN_HOLD(*vpp);

        AUTOFS_DPRINT((5, "auto_root: vfs %p, *vpp %p\n", (void *)vfsp,
            (void *)*vpp));
        return (0);
}

/*
 * Get file system statistics.
 */
static int
auto_statvfs(vfs_t *vfsp, struct statvfs64 *sbp)
{
        dev32_t d32;

        AUTOFS_DPRINT((4, "auto_statvfs %p\n", (void *)vfsp));

        bzero(sbp, sizeof (*sbp));
        sbp->f_bsize    = vfsp->vfs_bsize;
        sbp->f_frsize   = sbp->f_bsize;
        sbp->f_blocks   = (fsblkcnt64_t)0;
        sbp->f_bfree    = (fsblkcnt64_t)0;
        sbp->f_bavail   = (fsblkcnt64_t)0;
        sbp->f_files    = (fsfilcnt64_t)0;
        sbp->f_ffree    = (fsfilcnt64_t)0;
        sbp->f_favail   = (fsfilcnt64_t)0;
        (void) cmpldev(&d32, vfsp->vfs_dev);
        sbp->f_fsid     = d32;
        (void) strcpy(sbp->f_basetype, vfssw[vfsp->vfs_fstype].vsw_name);
        sbp->f_flag = vf_to_stf(vfsp->vfs_flag);
        sbp->f_namemax = MAXNAMELEN;
        (void) strcpy(sbp->f_fstr, MNTTYPE_AUTOFS);

        return (0);
}