2451 beadm umount should report if there is nothing to unmount

[unleashed.git] / usr / src / lib / libbe / common / be_mount.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) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
 */

/*
 * System includes
 */
#include <assert.h>
#include <errno.h>
#include <libintl.h>
#include <libnvpair.h>
#include <libzfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mntent.h>
#include <sys/mnttab.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfstab.h>
#include <sys/zone.h>
#include <sys/mkdev.h>
#include <unistd.h>

#include <libbe.h>
#include <libbe_priv.h>

#define BE_TMP_MNTPNT           "/tmp/.be.XXXXXX"

typedef struct dir_data {
        char *dir;
        char *ds;
} dir_data_t;

/* Private function prototypes */
static int be_mount_callback(zfs_handle_t *, void *);
static int be_unmount_callback(zfs_handle_t *, void *);
static int be_get_legacy_fs_callback(zfs_handle_t *, void *);
static int fix_mountpoint(zfs_handle_t *);
static int fix_mountpoint_callback(zfs_handle_t *, void *);
static int get_mountpoint_from_vfstab(char *, const char *, char *, size_t,
    boolean_t);
static int loopback_mount_shared_fs(zfs_handle_t *, be_mount_data_t *);
static int loopback_mount_zonepath(const char *, be_mount_data_t *);
static int iter_shared_fs_callback(zfs_handle_t *, void *);
static int zpool_shared_fs_callback(zpool_handle_t *, void *);
static int unmount_shared_fs(be_unmount_data_t *);
static int add_to_fs_list(be_fs_list_data_t *, const char *);
static int be_mount_root(zfs_handle_t *, char *);
static int be_unmount_root(zfs_handle_t *, be_unmount_data_t *);
static int be_mount_zones(zfs_handle_t *, be_mount_data_t *);
static int be_unmount_zones(be_unmount_data_t *);
static int be_mount_one_zone(zfs_handle_t *, be_mount_data_t *, char *, char *,
    char *);
static int be_unmount_one_zone(be_unmount_data_t *, char *, char *, char *);
static int be_get_ds_from_dir_callback(zfs_handle_t *, void *);


/* ******************************************************************** */
/*                      Public Functions                                */
/* ******************************************************************** */

/*
 * Function:    be_mount
 * Description: Mounts a BE and its subordinate datasets at a given mountpoint.
 * Parameters:
 *              be_attrs - pointer to nvlist_t of attributes being passed in.
 *                      The following attributes are used by this function:
 *
 *                      BE_ATTR_ORIG_BE_NAME            *required
 *                      BE_ATTR_MOUNTPOINT              *required
 *                      BE_ATTR_MOUNT_FLAGS             *optional
 * Return:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Public
 */
int
be_mount(nvlist_t *be_attrs)
{
        char            *be_name = NULL;
        char            *mountpoint = NULL;
        uint16_t        flags = 0;
        int             ret = BE_SUCCESS;

        /* Initialize libzfs handle */
        if (!be_zfs_init())
                return (BE_ERR_INIT);

        /* Get original BE name */
        if (nvlist_lookup_string(be_attrs, BE_ATTR_ORIG_BE_NAME, &be_name)
            != 0) {
                be_print_err(gettext("be_mount: failed to lookup "
                    "BE_ATTR_ORIG_BE_NAME attribute\n"));
                return (BE_ERR_INVAL);
        }

        /* Validate original BE name */
        if (!be_valid_be_name(be_name)) {
                be_print_err(gettext("be_mount: invalid BE name %s\n"),
                    be_name);
                return (BE_ERR_INVAL);
        }

        /* Get mountpoint */
        if (nvlist_lookup_string(be_attrs, BE_ATTR_MOUNTPOINT, &mountpoint)
            != 0) {
                be_print_err(gettext("be_mount: failed to lookup "
                    "BE_ATTR_MOUNTPOINT attribute\n"));
                return (BE_ERR_INVAL);
        }

        /* Get flags */
        if (nvlist_lookup_pairs(be_attrs, NV_FLAG_NOENTOK,
            BE_ATTR_MOUNT_FLAGS, DATA_TYPE_UINT16, &flags, NULL) != 0) {
                be_print_err(gettext("be_mount: failed to lookup "
                    "BE_ATTR_MOUNT_FLAGS attribute\n"));
                return (BE_ERR_INVAL);
        }

        ret = _be_mount(be_name, &mountpoint, flags);

        be_zfs_fini();

        return (ret);
}

/*
 * Function:    be_unmount
 * Description: Unmounts a BE and its subordinate datasets.
 * Parameters:
 *              be_attrs - pointer to nvlist_t of attributes being passed in.
 *                      The following attributes are used by this function:
 *
 *                      BE_ATTR_ORIG_BE_NAME            *required
 *                      BE_ATTR_UNMOUNT_FLAGS           *optional
 * Return:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Public
 */
int
be_unmount(nvlist_t *be_attrs)
{
        char            *be_name = NULL;
        char            *be_name_mnt = NULL;
        char            *ds = NULL;
        uint16_t        flags = 0;
        int             ret = BE_SUCCESS;

        /* Initialize libzfs handle */
        if (!be_zfs_init())
                return (BE_ERR_INIT);

        /* Get original BE name */
        if (nvlist_lookup_string(be_attrs, BE_ATTR_ORIG_BE_NAME, &be_name)
            != 0) {
                be_print_err(gettext("be_unmount: failed to lookup "
                    "BE_ATTR_ORIG_BE_NAME attribute\n"));
                return (BE_ERR_INVAL);
        }

        /* Check if we have mountpoint argument instead of BE name */
        if (be_name[0] == '/') {
                if ((ds = be_get_ds_from_dir(be_name)) != NULL) {
                        if ((be_name_mnt = strrchr(ds, '/')) != NULL) {
                                free(be_name);
                                be_name = be_name_mnt + 1;
                        }
                } else {
                        be_print_err(gettext("be_unmount: no datasets mounted "
                            "at '%s'\n"), be_name);
                        return (BE_ERR_INVAL);
                }
        }

        /* Validate original BE name */
        if (!be_valid_be_name(be_name)) {
                be_print_err(gettext("be_unmount: invalid BE name %s\n"),
                    be_name);
                return (BE_ERR_INVAL);
        }

        /* Get unmount flags */
        if (nvlist_lookup_pairs(be_attrs, NV_FLAG_NOENTOK,
            BE_ATTR_UNMOUNT_FLAGS, DATA_TYPE_UINT16, &flags, NULL) != 0) {
                be_print_err(gettext("be_unmount: failed to loookup "
                    "BE_ATTR_UNMOUNT_FLAGS attribute\n"));
                return (BE_ERR_INVAL);
        }

        ret = _be_unmount(be_name, flags);

        be_zfs_fini();

        return (ret);
}

/* ******************************************************************** */
/*                      Semi-Private Functions                          */
/* ******************************************************************** */

/*
 * Function:    _be_mount
 * Description: Mounts a BE.  If the altroot is not provided, this function
 *              will generate a temporary mountpoint to mount the BE at.  It
 *              will return this temporary mountpoint to the caller via the
 *              altroot reference pointer passed in.  This returned value is
 *              allocated on heap storage and is the repsonsibility of the
 *              caller to free.
 * Parameters:
 *              be_name - pointer to name of BE to mount.
 *              altroot - reference pointer to altroot of where to mount BE.
 *              flags - flag indicating special handling for mounting the BE
 * Return:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
_be_mount(char *be_name, char **altroot, int flags)
{
        be_transaction_data_t   bt = { 0 };
        be_mount_data_t md = { 0 };
        zfs_handle_t    *zhp;
        char            obe_root_ds[MAXPATHLEN];
        char            *mp = NULL;
        char            *tmp_altroot = NULL;
        int             ret = BE_SUCCESS, err = 0;
        uuid_t          uu = { 0 };
        boolean_t       gen_tmp_altroot = B_FALSE;

        if (be_name == NULL || altroot == NULL)
                return (BE_ERR_INVAL);

        /* Set be_name as obe_name in bt structure */
        bt.obe_name = be_name;

        /* Find which zpool obe_name lives in */
        if ((err = zpool_iter(g_zfs, be_find_zpool_callback, &bt)) == 0) {
                be_print_err(gettext("be_mount: failed to "
                    "find zpool for BE (%s)\n"), bt.obe_name);
                return (BE_ERR_BE_NOENT);
        } else if (err < 0) {
                be_print_err(gettext("be_mount: zpool_iter failed: %s\n"),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Generate string for obe_name's root dataset */
        be_make_root_ds(bt.obe_zpool, bt.obe_name, obe_root_ds,
            sizeof (obe_root_ds));
        bt.obe_root_ds = obe_root_ds;

        /* Get handle to BE's root dataset */
        if ((zhp = zfs_open(g_zfs, bt.obe_root_ds, ZFS_TYPE_FILESYSTEM)) ==
            NULL) {
                be_print_err(gettext("be_mount: failed to "
                    "open BE root dataset (%s): %s\n"), bt.obe_root_ds,
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Make sure BE's root dataset isn't already mounted somewhere */
        if (zfs_is_mounted(zhp, &mp)) {
                ZFS_CLOSE(zhp);
                be_print_err(gettext("be_mount: %s is already mounted "
                    "at %s\n"), bt.obe_name, mp != NULL ? mp : "");
                free(mp);
                return (BE_ERR_MOUNTED);
        }

        /*
         * Fix this BE's mountpoint if its root dataset isn't set to
         * either 'legacy' or '/'.
         */
        if ((ret = fix_mountpoint(zhp)) != BE_SUCCESS) {
                be_print_err(gettext("be_mount: mountpoint check "
                    "failed for %s\n"), bt.obe_root_ds);
                ZFS_CLOSE(zhp);
                return (ret);
        }

        /*
         * If altroot not provided, create a temporary alternate root
         * to mount on
         */
        if (*altroot == NULL) {
                if ((ret = be_make_tmp_mountpoint(&tmp_altroot))
                    != BE_SUCCESS) {
                        be_print_err(gettext("be_mount: failed to "
                            "make temporary mountpoint\n"));
                        ZFS_CLOSE(zhp);
                        return (ret);
                }
                gen_tmp_altroot = B_TRUE;
        } else {
                tmp_altroot = *altroot;
        }

        /* Mount the BE's root file system */
        if ((ret = be_mount_root(zhp, tmp_altroot)) != BE_SUCCESS) {
                be_print_err(gettext("be_mount: failed to "
                    "mount BE root file system\n"));
                if (gen_tmp_altroot)
                        free(tmp_altroot);
                ZFS_CLOSE(zhp);
                return (ret);
        }

        /* Iterate through BE's children filesystems */
        if ((err = zfs_iter_filesystems(zhp, be_mount_callback,
            tmp_altroot)) != 0) {
                be_print_err(gettext("be_mount: failed to "
                    "mount BE (%s) on %s\n"), bt.obe_name, tmp_altroot);
                if (gen_tmp_altroot)
                        free(tmp_altroot);
                ZFS_CLOSE(zhp);
                return (err);
        }

        md.altroot = tmp_altroot;
        md.shared_fs = flags & BE_MOUNT_FLAG_SHARED_FS;
        md.shared_rw = flags & BE_MOUNT_FLAG_SHARED_RW;

        /*
         * Mount shared file systems if mount flag says so.
         */
        if (md.shared_fs) {
                /*
                 * Mount all ZFS file systems not under the BE's root dataset
                 */
                (void) zpool_iter(g_zfs, zpool_shared_fs_callback, &md);

                /* TODO: Mount all non-ZFS file systems - Not supported yet */
        }

        /*
         * If we're in the global zone and the global zone has a valid uuid,
         * mount all supported non-global zones.
         */
        if (getzoneid() == GLOBAL_ZONEID &&
            !(flags & BE_MOUNT_FLAG_NO_ZONES) &&
            be_get_uuid(bt.obe_root_ds, &uu) == BE_SUCCESS) {
                if ((ret = be_mount_zones(zhp, &md)) != BE_SUCCESS) {
                        (void) _be_unmount(bt.obe_name, 0);
                        if (gen_tmp_altroot)
                                free(tmp_altroot);
                        ZFS_CLOSE(zhp);
                        return (ret);
                }
        }

        ZFS_CLOSE(zhp);

        /*
         * If a NULL altroot was passed in, pass the generated altroot
         * back to the caller in altroot.
         */
        if (gen_tmp_altroot)
                *altroot = tmp_altroot;

        return (BE_SUCCESS);
}

/*
 * Function:    _be_unmount
 * Description: Unmount a BE.
 * Parameters:
 *              be_name - pointer to name of BE to unmount.
 *              flags - flags for unmounting the BE.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
_be_unmount(char *be_name, int flags)
{
        be_transaction_data_t   bt = { 0 };
        be_unmount_data_t       ud = { 0 };
        zfs_handle_t    *zhp;
        uuid_t          uu = { 0 };
        char            obe_root_ds[MAXPATHLEN];
        char            mountpoint[MAXPATHLEN];
        char            *mp = NULL;
        int             ret = BE_SUCCESS;
        int             zret = 0;

        if (be_name == NULL)
                return (BE_ERR_INVAL);

        /* Set be_name as obe_name in bt structure */
        bt.obe_name = be_name;

        /* Find which zpool obe_name lives in */
        if ((zret = zpool_iter(g_zfs, be_find_zpool_callback, &bt)) == 0) {
                be_print_err(gettext("be_unmount: failed to "
                    "find zpool for BE (%s)\n"), bt.obe_name);
                return (BE_ERR_BE_NOENT);
        } else if (zret < 0) {
                be_print_err(gettext("be_unmount: "
                    "zpool_iter failed: %s\n"),
                    libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                return (ret);
        }

        /* Generate string for obe_name's root dataset */
        be_make_root_ds(bt.obe_zpool, bt.obe_name, obe_root_ds,
            sizeof (obe_root_ds));
        bt.obe_root_ds = obe_root_ds;

        /* Get handle to BE's root dataset */
        if ((zhp = zfs_open(g_zfs, bt.obe_root_ds, ZFS_TYPE_FILESYSTEM)) ==
            NULL) {
                be_print_err(gettext("be_unmount: failed to "
                    "open BE root dataset (%s): %s\n"), bt.obe_root_ds,
                    libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                return (ret);
        }

        /* Make sure BE's root dataset is mounted somewhere */
        if (!zfs_is_mounted(zhp, &mp)) {

                be_print_err(gettext("be_unmount: "
                    "(%s) not mounted\n"), bt.obe_name);

                /*
                 * BE is not mounted, fix this BE's mountpoint if its root
                 * dataset isn't set to either 'legacy' or '/'.
                 */
                if ((ret = fix_mountpoint(zhp)) != BE_SUCCESS) {
                        be_print_err(gettext("be_unmount: mountpoint check "
                            "failed for %s\n"), bt.obe_root_ds);
                        ZFS_CLOSE(zhp);
                        return (ret);
                }

                ZFS_CLOSE(zhp);
                return (BE_ERR_NOTMOUNTED);
        }

        /*
         * If we didn't get a mountpoint from the zfs_is_mounted call,
         * try and get it from its property.
         */
        if (mp == NULL) {
                if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
                    sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                        be_print_err(gettext("be_unmount: failed to "
                            "get mountpoint of (%s)\n"), bt.obe_name);
                        ZFS_CLOSE(zhp);
                        return (BE_ERR_ZFS);
                }
        } else {
                (void) strlcpy(mountpoint, mp, sizeof (mountpoint));
                free(mp);
        }

        /* If BE mounted as current root, fail */
        if (strcmp(mountpoint, "/") == 0) {
                be_print_err(gettext("be_unmount: "
                    "cannot unmount currently running BE\n"));
                ZFS_CLOSE(zhp);
                return (BE_ERR_UMOUNT_CURR_BE);
        }

        ud.altroot = mountpoint;
        ud.force = flags & BE_UNMOUNT_FLAG_FORCE;

        /* Unmount all supported non-global zones if we're in the global zone */
        if (getzoneid() == GLOBAL_ZONEID &&
            be_get_uuid(bt.obe_root_ds, &uu) == BE_SUCCESS) {
                if ((ret = be_unmount_zones(&ud)) != BE_SUCCESS) {
                        ZFS_CLOSE(zhp);
                        return (ret);
                }
        }

        /* TODO: Unmount all non-ZFS file systems - Not supported yet */

        /* Unmount all ZFS file systems not under the BE root dataset */
        if ((ret = unmount_shared_fs(&ud)) != BE_SUCCESS) {
                be_print_err(gettext("be_unmount: failed to "
                    "unmount shared file systems\n"));
                ZFS_CLOSE(zhp);
                return (ret);
        }

        /* Unmount all children datasets under the BE's root dataset */
        if ((zret = zfs_iter_filesystems(zhp, be_unmount_callback,
            &ud)) != 0) {
                be_print_err(gettext("be_unmount: failed to "
                    "unmount BE (%s)\n"), bt.obe_name);
                ZFS_CLOSE(zhp);
                return (zret);
        }

        /* Unmount this BE's root filesystem */
        if ((ret = be_unmount_root(zhp, &ud)) != BE_SUCCESS) {
                ZFS_CLOSE(zhp);
                return (ret);
        }

        ZFS_CLOSE(zhp);

        return (BE_SUCCESS);
}

/*
 * Function:    be_mount_zone_root
 * Description: Mounts the zone root dataset for a zone.
 * Parameters:
 *              zfs - zfs_handle_t pointer to zone root dataset
 *              md - be_mount_data_t pointer to data for zone to be mounted
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
be_mount_zone_root(zfs_handle_t *zhp, be_mount_data_t *md)
{
        char    mountpoint[MAXPATHLEN];
        int     err = 0;

        /* Get mountpoint property of dataset */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                be_print_err(gettext("be_mount_zone_root: failed to "
                    "get mountpoint property for %s: %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /*
         * Make sure zone's root dataset is set to 'legacy'.  This is
         * currently a requirement in this implementation of zones
         * support.
         */
        if (strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) != 0) {
                be_print_err(gettext("be_mount_zone_root: "
                    "zone root dataset mountpoint is not 'legacy'\n"));
                return (BE_ERR_ZONE_ROOT_NOT_LEGACY);
        }

        /*
         * Legacy mount the zone root dataset.
         *
         * As a workaround for 6176743, we mount the zone's root with the
         * MS_OVERLAY option in case an alternate BE is mounted, and we're
         * mounting the root for the zone from the current BE here.  When an
         * alternate BE is mounted, it ties up the zone's zoneroot directory
         * for the current BE since the zone's zonepath is loopback mounted
         * from the current BE.
         *
         * TODO: The MS_OVERLAY option needs to be removed when 6176743
         * is fixed.
         */
        if (mount(zfs_get_name(zhp), md->altroot, MS_OVERLAY, MNTTYPE_ZFS,
            NULL, 0, NULL, 0) != 0) {
                err = errno;
                be_print_err(gettext("be_mount_zone_root: failed to "
                    "legacy mount zone root dataset (%s) at %s\n"),
                    zfs_get_name(zhp), md->altroot);
                return (errno_to_be_err(err));
        }

        return (BE_SUCCESS);
}

/*
 * Function:    be_unmount_zone_root
 * Description: Unmounts the zone root dataset for a zone.
 * Parameters:
 *              zhp - zfs_handle_t pointer to zone root dataset
 *              ud - be_unmount_data_t pointer to data for zone to be unmounted
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wise use only)
 */
int
be_unmount_zone_root(zfs_handle_t *zhp, be_unmount_data_t *ud)
{
        char    mountpoint[MAXPATHLEN];

        /* Unmount the dataset */
        if (zfs_unmount(zhp, NULL, ud->force ? MS_FORCE : 0) != 0) {
                be_print_err(gettext("be_unmount_zone_root: failed to "
                    "unmount zone root dataset %s: %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Get the current mountpoint property for the zone root dataset */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                be_print_err(gettext("be_unmount_zone_root: failed to "
                    "get mountpoint property for zone root dataset (%s): %s\n"),
                    zfs_get_name(zhp), libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* If mountpoint not already set to 'legacy', set it to 'legacy' */
        if (strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) != 0) {
                if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                    ZFS_MOUNTPOINT_LEGACY) != 0) {
                        be_print_err(gettext("be_unmount_zone_root: "
                            "failed to set mountpoint of zone root dataset "
                            "%s to 'legacy': %s\n"), zfs_get_name(zhp),
                            libzfs_error_description(g_zfs));
                        return (zfs_err_to_be_err(g_zfs));
                }
        }

        return (BE_SUCCESS);
}

/*
 * Function:    be_get_legacy_fs
 * Description: This function iterates through all non-shared file systems
 *              of a BE and finds the ones with a legacy mountpoint.  For
 *              those file systems, it reads the BE's vfstab to get the
 *              mountpoint.  If found, it adds that file system to the
 *              be_fs_list_data_t passed in.
 *
 *              This function can be used to gather legacy mounted file systems
 *              for both global BEs and non-global zone BEs.  To get data for
 *              a non-global zone BE, the zoneroot_ds and zoneroot parameters
 *              will be specified, otherwise they should be set to NULL.
 * Parameters:
 *              be_name - global BE name from which to get legacy file
 *                      system list.
 *              be_root_ds - root dataset of global BE.
 *              zoneroot_ds - root dataset of zone.
 *              zoneroot - zoneroot path of zone.
 *              fld - be_fs_list_data_t pointer.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
be_get_legacy_fs(char *be_name, char *be_root_ds, char *zoneroot_ds,
    char *zoneroot, be_fs_list_data_t *fld)
{
        zfs_handle_t            *zhp = NULL;
        char                    mountpoint[MAXPATHLEN];
        boolean_t               mounted_here = B_FALSE;
        boolean_t               zone_mounted_here = B_FALSE;
        int                     ret = BE_SUCCESS, err = 0;

        if (be_name == NULL || be_root_ds == NULL || fld == NULL)
                return (BE_ERR_INVAL);

        /* Get handle to BE's root dataset */
        if ((zhp = zfs_open(g_zfs, be_root_ds, ZFS_TYPE_FILESYSTEM))
            == NULL) {
                be_print_err(gettext("be_get_legacy_fs: failed to "
                    "open BE root dataset (%s): %s\n"), be_root_ds,
                    libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                return (ret);
        }

        /* If BE is not already mounted, mount it. */
        if (!zfs_is_mounted(zhp, &fld->altroot)) {
                if ((ret = _be_mount(be_name, &fld->altroot,
                    zoneroot_ds ? BE_MOUNT_FLAG_NULL :
                    BE_MOUNT_FLAG_NO_ZONES)) != BE_SUCCESS) {
                        be_print_err(gettext("be_get_legacy_fs: "
                            "failed to mount BE %s\n"), be_name);
                        goto cleanup;
                }

                mounted_here = B_TRUE;
        } else if (fld->altroot == NULL) {
                be_print_err(gettext("be_get_legacy_fs: failed to "
                    "get altroot of mounted BE %s: %s\n"),
                    be_name, libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                goto cleanup;
        }

        /*
         * If a zone root dataset was passed in, we're wanting to get
         * legacy mounted file systems for that zone, not the global
         * BE.
         */
        if (zoneroot_ds != NULL) {
                be_mount_data_t         zone_md = { 0 };

                /* Close off handle to global BE's root dataset */
                ZFS_CLOSE(zhp);

                /* Get handle to zone's root dataset */
                if ((zhp = zfs_open(g_zfs, zoneroot_ds,
                    ZFS_TYPE_FILESYSTEM)) == NULL) {
                        be_print_err(gettext("be_get_legacy_fs: failed to "
                            "open zone BE root dataset (%s): %s\n"),
                            zoneroot_ds, libzfs_error_description(g_zfs));
                        ret = zfs_err_to_be_err(g_zfs);
                        goto cleanup;
                }

                /* Make sure the zone we're looking for is mounted */
                if (!zfs_is_mounted(zhp, &zone_md.altroot)) {
                        char    zone_altroot[MAXPATHLEN];

                        /* Generate alternate root path for zone */
                        (void) snprintf(zone_altroot, sizeof (zone_altroot),
                            "%s%s", fld->altroot, zoneroot);
                        if ((zone_md.altroot = strdup(zone_altroot)) == NULL) {
                                be_print_err(gettext("be_get_legacy_fs: "
                                    "memory allocation failed\n"));
                                ret = BE_ERR_NOMEM;
                                goto cleanup;
                        }

                        if ((ret = be_mount_zone_root(zhp, &zone_md))
                            != BE_SUCCESS) {
                                be_print_err(gettext("be_get_legacy_fs: "
                                    "failed to mount zone root %s\n"),
                                    zoneroot_ds);
                                free(zone_md.altroot);
                                zone_md.altroot = NULL;
                                goto cleanup;
                        }
                        zone_mounted_here = B_TRUE;
                }

                free(fld->altroot);
                fld->altroot = zone_md.altroot;
        }

        /*
         * If the root dataset is in the vfstab with a mountpoint of "/",
         * add it to the list
         */
        if (get_mountpoint_from_vfstab(fld->altroot, zfs_get_name(zhp),
            mountpoint, sizeof (mountpoint), B_FALSE) == BE_SUCCESS) {
                if (strcmp(mountpoint, "/") == 0) {
                        if (add_to_fs_list(fld, zfs_get_name(zhp))
                            != BE_SUCCESS) {
                                be_print_err(gettext("be_get_legacy_fs: "
                                    "failed to add %s to fs list\n"),
                                    zfs_get_name(zhp));
                                ret = BE_ERR_INVAL;
                                goto cleanup;
                        }
                }
        }

        /* Iterate subordinate file systems looking for legacy mounts */
        if ((ret = zfs_iter_filesystems(zhp, be_get_legacy_fs_callback,
            fld)) != 0) {
                be_print_err(gettext("be_get_legacy_fs: "
                    "failed to iterate  %s to get legacy mounts\n"),
                    zfs_get_name(zhp));
        }

cleanup:
        /* If we mounted the zone BE, unmount it */
        if (zone_mounted_here) {
                be_unmount_data_t       zone_ud = { 0 };

                zone_ud.altroot = fld->altroot;
                zone_ud.force = B_TRUE;
                if ((err = be_unmount_zone_root(zhp, &zone_ud)) != BE_SUCCESS) {
                        be_print_err(gettext("be_get_legacy_fs: "
                            "failed to unmount zone root %s\n"),
                            zoneroot_ds);
                        if (ret == BE_SUCCESS)
                                ret = err;
                }
        }

        /* If we mounted this BE, unmount it */
        if (mounted_here) {
                if ((err = _be_unmount(be_name, 0)) != BE_SUCCESS) {
                        be_print_err(gettext("be_get_legacy_fs: "
                            "failed to unmount %s\n"), be_name);
                        if (ret == BE_SUCCESS)
                                ret = err;
                }
        }

        ZFS_CLOSE(zhp);

        free(fld->altroot);
        fld->altroot = NULL;

        return (ret);
}

/*
 * Function:    be_free_fs_list
 * Description: Function used to free the members of a be_fs_list_data_t
 *                      structure.
 * Parameters:
 *              fld - be_fs_list_data_t pointer to free.
 * Returns:
 *              None
 * Scope:
 *              Semi-private (library wide use only)
 */
void
be_free_fs_list(be_fs_list_data_t *fld)
{
        int     i;

        if (fld == NULL)
                return;

        free(fld->altroot);

        if (fld->fs_list == NULL)
                return;

        for (i = 0; i < fld->fs_num; i++)
                free(fld->fs_list[i]);

        free(fld->fs_list);
}

/*
 * Function:    be_get_ds_from_dir(char *dir)
 * Description: Given a directory path, find the underlying dataset mounted
 *              at that directory path if there is one.   The returned name
 *              is allocated in heap storage, so the caller is responsible
 *              for freeing it.
 * Parameters:
 *              dir - char pointer of directory to find.
 * Returns:
 *              NULL - if directory is not mounted from a dataset.
 *              name of dataset mounted at dir.
 * Scope:
 *              Semi-private (library wide use only)
 */
char *
be_get_ds_from_dir(char *dir)
{
        dir_data_t      dd = { 0 };
        char            resolved_dir[MAXPATHLEN];

        /* Make sure length of dir is within the max length */
        if (dir == NULL || strlen(dir) >= MAXPATHLEN)
                return (NULL);

        /* Resolve dir in case its lofs mounted */
        (void) strlcpy(resolved_dir, dir, sizeof (resolved_dir));
        z_resolve_lofs(resolved_dir, sizeof (resolved_dir));

        dd.dir = resolved_dir;

        (void) zfs_iter_root(g_zfs, be_get_ds_from_dir_callback, &dd);

        return (dd.ds);
}

/*
 * Function:    be_make_tmp_mountpoint
 * Description: This function generates a random temporary mountpoint
 *              and creates that mountpoint directory.  It returns the
 *              mountpoint in heap storage, so the caller is responsible
 *              for freeing it.
 * Parameters:
 *              tmp_mp - reference to pointer of where to store generated
 *                      temporary mountpoint.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
be_make_tmp_mountpoint(char **tmp_mp)
{
        int     err = 0;

        if ((*tmp_mp = (char *)calloc(1, sizeof (BE_TMP_MNTPNT) + 1)) == NULL) {
                be_print_err(gettext("be_make_tmp_mountpoint: "
                    "malloc failed\n"));
                return (BE_ERR_NOMEM);
        }
        (void) strlcpy(*tmp_mp, BE_TMP_MNTPNT, sizeof (BE_TMP_MNTPNT) + 1);
        if (mkdtemp(*tmp_mp) == NULL) {
                err = errno;
                be_print_err(gettext("be_make_tmp_mountpoint: mkdtemp() failed "
                    "for %s: %s\n"), *tmp_mp, strerror(err));
                free(*tmp_mp);
                *tmp_mp = NULL;
                return (errno_to_be_err(err));
        }

        return (BE_SUCCESS);
}

/*
 * Function:    be_mount_pool
 * Description: This function determines if the pool's datase is mounted
 *              and if not it is used to mount the pool's dataset. The
 *              function returns the current mountpoint if we are able
 *              to mount the dataset.
 * Parameters:
 *              zhp - handle to the pool's dataset
 *              tmp_mntpnt - The temporary mountpoint that the pool's
 *                            dataset is mounted on. This is set only
 *                            if the attempt to mount the dataset at it's
 *                            set mountpoint fails, and we've used a
 *                            temporary mount point for this dataset. It
 *                            is expected that the caller will free this
 *                            memory.
 *              orig_mntpnt - The original mountpoint for the pool. If a
 *                            temporary mount point was needed this will
 *                            be used to reset the mountpoint property to
 *                            it's original mountpoint. It is expected that
 *                            the caller will free this memory.
 *              pool_mounted - This flag indicates that the pool was mounted
 *                             in this function.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
be_mount_pool(
        zfs_handle_t *zhp,
        char **tmp_mntpnt,
        char **orig_mntpnt,
        boolean_t *pool_mounted)
{

        char            mountpoint[MAXPATHLEN];
        int             ret = 0;

        *tmp_mntpnt = NULL;
        *orig_mntpnt = NULL;
        *pool_mounted = B_FALSE;

        if (!zfs_is_mounted(zhp, NULL)) {
                if (zfs_mount(zhp, NULL, 0) != 0) {
                        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
                            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                                be_print_err(gettext("be_mount_pool: failed to "
                                    "get mountpoint of (%s): %s\n"),
                                    zfs_get_name(zhp),
                                    libzfs_error_description(g_zfs));
                                return (zfs_err_to_be_err(g_zfs));
                        }
                        if ((*orig_mntpnt = strdup(mountpoint)) == NULL) {
                                be_print_err(gettext("be_mount_pool: memory "
                                    "allocation failed\n"));
                                return (BE_ERR_NOMEM);
                        }
                        /*
                         * attempt to mount on a temp mountpoint
                         */
                        if ((ret = be_make_tmp_mountpoint(tmp_mntpnt))
                            != BE_SUCCESS) {
                                be_print_err(gettext("be_mount_pool: failed "
                                    "to make temporary mountpoint\n"));
                                free(*orig_mntpnt);
                                *orig_mntpnt = NULL;
                                return (ret);
                        }

                        if (zfs_prop_set(zhp,
                            zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                            *tmp_mntpnt) != 0) {
                                be_print_err(gettext("be_mount_pool: failed "
                                    "to set mountpoint of pool dataset %s to "
                                    "%s: %s\n"), zfs_get_name(zhp),
                                    *orig_mntpnt,
                                    libzfs_error_description(g_zfs));
                                free(*tmp_mntpnt);
                                free(*orig_mntpnt);
                                *orig_mntpnt = NULL;
                                *tmp_mntpnt = NULL;
                                return (zfs_err_to_be_err(g_zfs));
                        }

                        if (zfs_mount(zhp, NULL, 0) != 0) {
                                be_print_err(gettext("be_mount_pool: failed "
                                    "to mount dataset %s at %s: %s\n"),
                                    zfs_get_name(zhp), *tmp_mntpnt,
                                    libzfs_error_description(g_zfs));
                                ret = zfs_err_to_be_err(g_zfs);
                                if (zfs_prop_set(zhp,
                                    zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                                    mountpoint) != 0) {
                                        be_print_err(gettext("be_mount_pool: "
                                            "failed to set mountpoint of pool "
                                            "dataset %s to %s: %s\n"),
                                            zfs_get_name(zhp), *tmp_mntpnt,
                                            libzfs_error_description(g_zfs));
                                }
                                free(*tmp_mntpnt);
                                free(*orig_mntpnt);
                                *orig_mntpnt = NULL;
                                *tmp_mntpnt = NULL;
                                return (ret);
                        }
                }
                *pool_mounted = B_TRUE;
        }

        return (BE_SUCCESS);
}

/*
 * Function:    be_unmount_pool
 * Description: This function is used to unmount the pool's dataset if we
 *              mounted it previously using be_mount_pool().
 * Parameters:
 *              zhp - handle to the pool's dataset
 *              tmp_mntpnt - If a temprary mount point was used this will
 *                           be set. Since this was created in be_mount_pool
 *                           we will need to clean it up here.
 *              orig_mntpnt - The original mountpoint for the pool. This is
 *                            used to set the dataset mountpoint property
 *                            back to it's original value in the case where a
 *                            temporary mountpoint was used.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Semi-private (library wide use only)
 */
int
be_unmount_pool(
        zfs_handle_t *zhp,
        char *tmp_mntpnt,
        char *orig_mntpnt)
{
        if (zfs_unmount(zhp, NULL, 0) != 0) {
                be_print_err(gettext("be_unmount_pool: failed to "
                    "unmount pool (%s): %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }
        if (orig_mntpnt != NULL) {
                if (tmp_mntpnt != NULL &&
                    strcmp(orig_mntpnt, tmp_mntpnt) != 0) {
                        (void) rmdir(tmp_mntpnt);
                }
                if (zfs_prop_set(zhp,
                    zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                    orig_mntpnt) != 0) {
                        be_print_err(gettext("be_unmount_pool: failed "
                            "to set the mountpoint for dataset (%s) to "
                            "%s: %s\n"), zfs_get_name(zhp), orig_mntpnt,
                            libzfs_error_description(g_zfs));
                        return (zfs_err_to_be_err(g_zfs));
                }
        }

        return (BE_SUCCESS);
}

/* ******************************************************************** */
/*                      Private Functions                               */
/* ******************************************************************** */

/*
 * Function:    be_mount_callback
 * Description: Callback function used to iterate through all of a BE's
 *              subordinate file systems and to mount them accordingly.
 * Parameters:
 *              zhp - zfs_handle_t pointer to current file system being
 *                      processed.
 *              data - pointer to the altroot of where to mount BE.
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_mount_callback(zfs_handle_t *zhp, void *data)
{
        zprop_source_t  sourcetype;
        const char      *fs_name = zfs_get_name(zhp);
        char            source[ZFS_MAXNAMELEN];
        char            *altroot = data;
        char            zhp_mountpoint[MAXPATHLEN];
        char            mountpoint[MAXPATHLEN];
        int             ret = 0;

        /* Get dataset's mountpoint and source values */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, zhp_mountpoint,
            sizeof (zhp_mountpoint), &sourcetype, source, sizeof (source),
            B_FALSE) != 0) {
                be_print_err(gettext("be_mount_callback: failed to "
                    "get mountpoint and sourcetype for %s\n"),
                    fs_name);
                ZFS_CLOSE(zhp);
                return (BE_ERR_ZFS);
        }

        /*
         * Set this filesystem's 'canmount' property to 'noauto' just incase
         * it's been set 'on'.  We do this so that when we change its
         * mountpoint zfs won't immediately try to mount it.
         */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_CANMOUNT), "noauto")) {
                be_print_err(gettext("be_mount_callback: failed to "
                    "set canmount to 'noauto' (%s)\n"), fs_name);
                ZFS_CLOSE(zhp);
                return (BE_ERR_ZFS);
        }

        /*
         * If the mountpoint is none, there's nothing to do, goto next.
         * If the mountpoint is legacy, legacy mount it with mount(2).
         * If the mountpoint is inherited, its mountpoint should
         * already be set.  If it's not, then explicitly fix-up
         * the mountpoint now by appending its explicitly set
         * mountpoint value to the BE mountpoint.
         */
        if (strcmp(zhp_mountpoint, ZFS_MOUNTPOINT_NONE) == 0) {
                goto next;
        } else if (strcmp(zhp_mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0) {
                /*
                 * If the mountpoint is set to 'legacy', we need to
                 * dig into this BE's vfstab to figure out where to
                 * mount it, and just mount it via mount(2).
                 */
                if (get_mountpoint_from_vfstab(altroot, fs_name,
                    mountpoint, sizeof (mountpoint), B_TRUE) == BE_SUCCESS) {

                        /* Legacy mount the file system */
                        if (mount(fs_name, mountpoint, MS_DATA,
                            MNTTYPE_ZFS, NULL, 0, NULL, 0) != 0) {
                                be_print_err(
                                    gettext("be_mount_callback: "
                                    "failed to mount %s on %s\n"),
                                    fs_name, mountpoint);
                        }
                } else {
                        be_print_err(
                            gettext("be_mount_callback: "
                            "no entry for %s in vfstab, "
                            "skipping ...\n"), fs_name);
                }

                goto next;

        } else if (sourcetype & ZPROP_SRC_INHERITED) {
                /*
                 * If the mountpoint is inherited, its parent should have
                 * already been processed so its current mountpoint value
                 * is what its mountpoint ought to be.
                 */
                (void) strlcpy(mountpoint, zhp_mountpoint, sizeof (mountpoint));
        } else if (sourcetype & ZPROP_SRC_LOCAL) {
                /*
                 * Else process dataset with explicitly set mountpoint.
                 */
                (void) snprintf(mountpoint, sizeof (mountpoint),
                    "%s%s", altroot, zhp_mountpoint);

                /* Set the new mountpoint for the dataset */
                if (zfs_prop_set(zhp,
                    zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                    mountpoint)) {
                        be_print_err(gettext("be_mount_callback: "
                            "failed to set mountpoint for %s to "
                            "%s\n"), fs_name, mountpoint);
                        ZFS_CLOSE(zhp);
                        return (BE_ERR_ZFS);
                }
        } else {
                be_print_err(gettext("be_mount_callback: "
                    "mountpoint sourcetype of %s is %d, skipping ...\n"),
                    fs_name, sourcetype);

                goto next;
        }

        /* Mount this filesystem */
        if (zfs_mount(zhp, NULL, 0) != 0) {
                be_print_err(gettext("be_mount_callback: failed to "
                    "mount dataset %s at %s: %s\n"), fs_name, mountpoint,
                    libzfs_error_description(g_zfs));
                /*
                 * Set this filesystem's 'mountpoint' property back to what
                 * it was
                 */
                if (sourcetype & ZPROP_SRC_LOCAL &&
                    strcmp(zhp_mountpoint, ZFS_MOUNTPOINT_LEGACY) != 0) {
                        (void) zfs_prop_set(zhp,
                            zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                            zhp_mountpoint);
                }

                ZFS_CLOSE(zhp);
                return (BE_ERR_MOUNT);
        }

next:
        /* Iterate through this dataset's children and mount them */
        if ((ret = zfs_iter_filesystems(zhp, be_mount_callback,
            altroot)) != 0) {
                ZFS_CLOSE(zhp);
                return (ret);
        }


        ZFS_CLOSE(zhp);
        return (0);
}

/*
 * Function:    be_unmount_callback
 * Description: Callback function used to iterate through all of a BE's
 *              subordinate file systems and to unmount them.
 * Parameters:
 *              zhp - zfs_handle_t pointer to current file system being
 *                      processed.
 *              data - pointer to the mountpoint of where BE is mounted.
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_unmount_callback(zfs_handle_t *zhp, void *data)
{
        be_unmount_data_t       *ud = data;
        zprop_source_t  sourcetype;
        const char      *fs_name = zfs_get_name(zhp);
        char            source[ZFS_MAXNAMELEN];
        char            mountpoint[MAXPATHLEN];
        char            *zhp_mountpoint;
        int             ret = 0;

        /* Iterate down this dataset's children first */
        if (zfs_iter_filesystems(zhp, be_unmount_callback, ud)) {
                ret = BE_ERR_UMOUNT;
                goto done;
        }

        /* Is dataset even mounted ? */
        if (!zfs_is_mounted(zhp, NULL))
                goto done;

        /* Unmount this file system */
        if (zfs_unmount(zhp, NULL, ud->force ? MS_FORCE : 0) != 0) {
                be_print_err(gettext("be_unmount_callback: "
                    "failed to unmount %s: %s\n"), fs_name,
                    libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                goto done;
        }

        /* Get dataset's current mountpoint and source value */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), &sourcetype, source, sizeof (source),
            B_FALSE) != 0) {
                be_print_err(gettext("be_unmount_callback: "
                    "failed to get mountpoint and sourcetype for %s: %s\n"),
                    fs_name, libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                goto done;
        }

        if (sourcetype & ZPROP_SRC_INHERITED) {
                /*
                 * If the mountpoint is inherited we don't need to
                 * do anything.  When its parent gets processed
                 * its mountpoint will be set accordingly.
                 */
                goto done;
        } else if (sourcetype & ZPROP_SRC_LOCAL) {

                if (strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0) {
                        /*
                         * If the mountpoint is set to 'legacy', its already
                         * been unmounted (from above call to zfs_unmount), and
                         * we don't need to do anything else with it.
                         */
                        goto done;

                } else {
                        /*
                         * Else process dataset with explicitly set mountpoint.
                         */

                        /*
                         * Get this dataset's mountpoint relative to
                         * the BE's mountpoint.
                         */
                        if ((strncmp(mountpoint, ud->altroot,
                            strlen(ud->altroot)) == 0) &&
                            (mountpoint[strlen(ud->altroot)] == '/')) {

                                zhp_mountpoint = mountpoint +
                                    strlen(ud->altroot);

                                /* Set this dataset's mountpoint value */
                                if (zfs_prop_set(zhp,
                                    zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                                    zhp_mountpoint)) {
                                        be_print_err(
                                            gettext("be_unmount_callback: "
                                            "failed to set mountpoint for "
                                            "%s to %s: %s\n"), fs_name,
                                            zhp_mountpoint,
                                            libzfs_error_description(g_zfs));
                                        ret = zfs_err_to_be_err(g_zfs);
                                }
                        } else {
                                be_print_err(
                                    gettext("be_unmount_callback: "
                                    "%s not mounted under BE's altroot %s, "
                                    "skipping ...\n"), fs_name, ud->altroot);
                                /*
                                 * fs_name is mounted but not under the
                                 * root for this BE.
                                 */
                                ret = BE_ERR_INVALMOUNTPOINT;
                        }
                }
        } else {
                be_print_err(gettext("be_unmount_callback: "
                    "mountpoint sourcetype of %s is %d, skipping ...\n"),
                    fs_name, sourcetype);
                ret = BE_ERR_ZFS;
        }

done:
        /* Set this filesystem's 'canmount' property to 'noauto' */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_CANMOUNT), "noauto")) {
                be_print_err(gettext("be_unmount_callback: "
                    "failed to set canmount to 'noauto' (%s)\n"), fs_name);
                if (ret == 0)
                        ret = BE_ERR_ZFS;
        }

        ZFS_CLOSE(zhp);
        return (ret);
}

/*
 * Function:    be_get_legacy_fs_callback
 * Description: The callback function is used to iterate through all
 *              non-shared file systems of a BE, finding ones that have
 *              a legacy mountpoint and an entry in the BE's vfstab.
 *              It adds these file systems to the callback data.
 * Parameters:
 *              zhp - zfs_handle_t pointer to current file system being
 *                      processed.
 *              data - be_fs_list_data_t pointer
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_get_legacy_fs_callback(zfs_handle_t *zhp, void *data)
{
        be_fs_list_data_t       *fld = data;
        const char              *fs_name = zfs_get_name(zhp);
        char                    zhp_mountpoint[MAXPATHLEN];
        char                    mountpoint[MAXPATHLEN];
        int                     ret = 0;

        /* Get this dataset's mountpoint property */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, zhp_mountpoint,
            sizeof (zhp_mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                be_print_err(gettext("be_get_legacy_fs_callback: "
                    "failed to get mountpoint for %s: %s\n"),
                    fs_name, libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                ZFS_CLOSE(zhp);
                return (ret);
        }

        /*
         * If mountpoint is legacy, try to get its mountpoint from this BE's
         * vfstab.  If it exists in the vfstab, add this file system to the
         * callback data.
         */
        if (strcmp(zhp_mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0) {
                if (get_mountpoint_from_vfstab(fld->altroot, fs_name,
                    mountpoint, sizeof (mountpoint), B_FALSE) != BE_SUCCESS) {
                        be_print_err(gettext("be_get_legacy_fs_callback: "
                            "no entry for %s in vfstab, "
                            "skipping ...\n"), fs_name);

                        goto next;
                }

                /* Record file system into the callback data. */
                if (add_to_fs_list(fld, zfs_get_name(zhp)) != BE_SUCCESS) {
                        be_print_err(gettext("be_get_legacy_fs_callback: "
                            "failed to add %s to fs list\n"), mountpoint);
                        ZFS_CLOSE(zhp);
                        return (BE_ERR_NOMEM);
                }
        }

next:
        /* Iterate through this dataset's children file systems */
        if ((ret = zfs_iter_filesystems(zhp, be_get_legacy_fs_callback,
            fld)) != 0) {
                ZFS_CLOSE(zhp);
                return (ret);
        }
        ZFS_CLOSE(zhp);
        return (0);
}

/*
 * Function:    add_to_fs_list
 * Description: Function used to add a file system to the fs_list array in
 *                      a be_fs_list_data_t structure.
 * Parameters:
 *              fld - be_fs_list_data_t pointer
 *              fs - file system to add
 * Returns:
 *              BE_SUCCESS - Success
 *              1 - Failure
 * Scope:
 *              Private
 */
static int
add_to_fs_list(be_fs_list_data_t *fld, const char *fs)
{
        if (fld == NULL || fs == NULL)
                return (1);

        if ((fld->fs_list = (char **)realloc(fld->fs_list,
            sizeof (char *)*(fld->fs_num + 1))) == NULL) {
                be_print_err(gettext("add_to_fs_list: "
                    "memory allocation failed\n"));
                return (1);
        }

        if ((fld->fs_list[fld->fs_num++] = strdup(fs)) == NULL) {
                be_print_err(gettext("add_to_fs_list: "
                    "memory allocation failed\n"));
                return (1);
        }

        return (BE_SUCCESS);
}

/*
 * Function:    zpool_shared_fs_callback
 * Description: Callback function used to iterate through all existing pools
 *              to find and mount all shared filesystems.  This function
 *              processes the pool's "pool data" dataset, then uses
 *              iter_shared_fs_callback to iterate through the pool's
 *              datasets.
 * Parameters:
 *              zlp - zpool_handle_t pointer to the current pool being
 *                      looked at.
 *              data - be_mount_data_t pointer
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
zpool_shared_fs_callback(zpool_handle_t *zlp, void *data)
{
        be_mount_data_t *md = data;
        zfs_handle_t    *zhp = NULL;
        const char      *zpool = zpool_get_name(zlp);
        int             ret = 0;

        /*
         * Get handle to pool's "pool data" dataset
         */
        if ((zhp = zfs_open(g_zfs, zpool, ZFS_TYPE_FILESYSTEM)) == NULL) {
                be_print_err(gettext("zpool_shared_fs: "
                    "failed to open pool dataset %s: %s\n"), zpool,
                    libzfs_error_description(g_zfs));
                ret = zfs_err_to_be_err(g_zfs);
                zpool_close(zlp);
                return (ret);
        }

        /* Process this pool's "pool data" dataset */
        (void) loopback_mount_shared_fs(zhp, md);

        /* Interate through this pool's children */
        (void) zfs_iter_filesystems(zhp, iter_shared_fs_callback, md);

        ZFS_CLOSE(zhp);
        zpool_close(zlp);

        return (0);
}

/*
 * Function:    iter_shared_fs_callback
 * Description: Callback function used to iterate through a pool's datasets
 *              to find and mount all shared filesystems.  It makes sure to
 *              find the BE container dataset of the pool, if it exists, and
 *              does not process and iterate down that path.
 *
 *              Note - This function iterates linearly down the
 *              hierarchical dataset paths and mounts things as it goes
 *              along.  It does not make sure that something deeper down
 *              a dataset path has an interim mountpoint for something
 *              processed earlier.
 *
 * Parameters:
 *              zhp - zfs_handle_t pointer to the current dataset being
 *                      processed.
 *              data - be_mount_data_t pointer
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
iter_shared_fs_callback(zfs_handle_t *zhp, void *data)
{
        be_mount_data_t *md = data;
        const char      *name = zfs_get_name(zhp);
        char            container_ds[MAXPATHLEN];
        char            tmp_name[MAXPATHLEN];
        char            *pool;

        /* Get the pool's name */
        (void) strlcpy(tmp_name, name, sizeof (tmp_name));
        pool = strtok(tmp_name, "/");

        if (pool) {
                /* Get the name of this pool's container dataset */
                be_make_container_ds(pool, container_ds,
                    sizeof (container_ds));

                /*
                 * If what we're processing is this pool's BE container
                 * dataset, skip it.
                 */
                if (strcmp(name, container_ds) == 0) {
                        ZFS_CLOSE(zhp);
                        return (0);
                }
        } else {
                /* Getting the pool name failed, return error */
                be_print_err(gettext("iter_shared_fs_callback: "
                    "failed to get pool name from %s\n"), name);
                ZFS_CLOSE(zhp);
                return (BE_ERR_POOL_NOENT);
        }

        /* Mount this shared filesystem */
        (void) loopback_mount_shared_fs(zhp, md);

        /* Iterate this dataset's children file systems */
        (void) zfs_iter_filesystems(zhp, iter_shared_fs_callback, md);
        ZFS_CLOSE(zhp);

        return (0);
}

/*
 * Function:    loopback_mount_shared_fs
 * Description: This function loopback mounts a file system into the altroot
 *              area of the BE being mounted.  Since these are shared file
 *              systems, they are expected to be already mounted for the
 *              current BE, and this function just loopback mounts them into
 *              the BE mountpoint.  If they are not mounted for the current
 *              live system, they are skipped and not mounted into the BE
 *              we're mounting.
 * Parameters:
 *              zhp - zfs_handle_t pointer to the dataset to loopback mount
 *              md - be_mount_data_t pointer
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
loopback_mount_shared_fs(zfs_handle_t *zhp, be_mount_data_t *md)
{
        char            zhp_mountpoint[MAXPATHLEN];
        char            mountpoint[MAXPATHLEN];
        char            *mp = NULL;
        char            optstr[MAX_MNTOPT_STR];
        int             mflag = MS_OPTIONSTR;
        int             err;

        /*
         * Check if file system is currently mounted and not delegated
         * to a non-global zone (if we're in the global zone)
         */
        if (zfs_is_mounted(zhp, &mp) && (getzoneid() != GLOBAL_ZONEID ||
            !zfs_prop_get_int(zhp, ZFS_PROP_ZONED))) {
                /*
                 * If we didn't get a mountpoint from the zfs_is_mounted call,
                 * get it from the mountpoint property.
                 */
                if (mp == NULL) {
                        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT,
                            zhp_mountpoint, sizeof (zhp_mountpoint), NULL,
                            NULL, 0, B_FALSE) != 0) {
                                be_print_err(
                                    gettext("loopback_mount_shared_fs: "
                                    "failed to get mountpoint property\n"));
                                return (BE_ERR_ZFS);
                        }
                } else {
                        (void) strlcpy(zhp_mountpoint, mp,
                            sizeof (zhp_mountpoint));
                        free(mp);
                }

                (void) snprintf(mountpoint, sizeof (mountpoint), "%s%s",
                    md->altroot, zhp_mountpoint);

                /* Mount it read-only if read-write was not requested */
                if (!md->shared_rw) {
                        mflag |= MS_RDONLY;
                }

                /* Add the "nosub" option to the mount options string */
                (void) strlcpy(optstr, MNTOPT_NOSUB, sizeof (optstr));

                /* Loopback mount this dataset at the altroot */
                if (mount(zhp_mountpoint, mountpoint, mflag, MNTTYPE_LOFS,
                    NULL, 0, optstr, sizeof (optstr)) != 0) {
                        err = errno;
                        be_print_err(gettext("loopback_mount_shared_fs: "
                            "failed to loopback mount %s at %s: %s\n"),
                            zhp_mountpoint, mountpoint, strerror(err));
                        return (BE_ERR_MOUNT);
                }
        }

        return (BE_SUCCESS);
}

/*
 * Function:    loopback_mount_zonepath
 * Description: This function loopback mounts a zonepath into the altroot
 *              area of the BE being mounted.  Since these are shared file
 *              systems, they are expected to be already mounted for the
 *              current BE, and this function just loopback mounts them into
 *              the BE mountpoint.
 * Parameters:
 *              zonepath - pointer to zone path in the current BE
 *              md - be_mount_data_t pointer
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
loopback_mount_zonepath(const char *zonepath, be_mount_data_t *md)
{
        FILE            *fp = (FILE *)NULL;
        struct stat     st;
        char            *p;
        char            *p1;
        char            *parent_dir;
        struct extmnttab        extmtab;
        dev_t           dev = NODEV;
        char            *parentmnt;
        char            alt_parentmnt[MAXPATHLEN];
        struct mnttab   mntref;
        char            altzonepath[MAXPATHLEN];
        char            optstr[MAX_MNTOPT_STR];
        int             mflag = MS_OPTIONSTR;
        int             ret;
        int             err;

        fp = fopen(MNTTAB, "r");
        if (fp == NULL) {
                err = errno;
                be_print_err(gettext("loopback_mount_zonepath: "
                    "failed to open /etc/mnttab\n"));
                return (errno_to_be_err(err));
        }

        /*
         * before attempting the loopback mount of zonepath under altroot,
         * we need to make sure that all intermediate file systems in the
         * zone path are also mounted under altroot
         */

        /* get the parent directory for zonepath */
        p = strrchr(zonepath, '/');
        if (p != NULL && p != zonepath) {
                if ((parent_dir = (char *)calloc(sizeof (char),
                    p - zonepath + 1)) == NULL) {
                        ret = BE_ERR_NOMEM;
                        goto done;
                }
                (void) strlcpy(parent_dir, zonepath, p - zonepath + 1);
                if (stat(parent_dir, &st) < 0) {
                        ret = errno_to_be_err(errno);
                        be_print_err(gettext("loopback_mount_zonepath: "
                            "failed to stat %s"),
                            parent_dir);
                        free(parent_dir);
                        goto done;
                }
                free(parent_dir);

                /*
                 * After the above stat call, st.st_dev contains ID of the
                 * device over which parent dir resides.
                 * Now, search mnttab and find mount point of parent dir device.
                 */

                resetmnttab(fp);
                while (getextmntent(fp, &extmtab, sizeof (extmtab)) == 0) {
                        dev = makedev(extmtab.mnt_major, extmtab.mnt_minor);
                        if (st.st_dev == dev && strcmp(extmtab.mnt_fstype,
                            MNTTYPE_ZFS) == 0) {
                                p1 = strchr(extmtab.mnt_special, '/');
                                if (p1 == NULL || strncmp(p1 + 1,
                                    BE_CONTAINER_DS_NAME, 4) != 0 ||
                                    (*(p1 + 5) != '/' && *(p1 + 5) != '\0')) {
                                        /*
                                         * if parent dir is in a shared file
                                         * system, check whether it is already
                                         * loopback mounted under altroot or
                                         * not.  It would have been mounted
                                         * already under altroot if it is in
                                         * a non-shared filesystem.
                                         */
                                        parentmnt = strdup(extmtab.mnt_mountp);
                                        (void) snprintf(alt_parentmnt,
                                            sizeof (alt_parentmnt), "%s%s",
                                            md->altroot, parentmnt);
                                        mntref.mnt_mountp = alt_parentmnt;
                                        mntref.mnt_special = parentmnt;
                                        mntref.mnt_fstype = MNTTYPE_LOFS;
                                        mntref.mnt_mntopts = NULL;
                                        mntref.mnt_time = NULL;
                                        resetmnttab(fp);
                                        if (getmntany(fp, (struct mnttab *)
                                            &extmtab, &mntref) != 0) {
                                                ret = loopback_mount_zonepath(
                                                    parentmnt, md);
                                                if (ret != BE_SUCCESS) {
                                                        free(parentmnt);
                                                        goto done;
                                                }
                                        }
                                        free(parentmnt);
                                }
                                break;
                        }
                }
        }


        if (!md->shared_rw) {
                mflag |= MS_RDONLY;
        }

        (void) snprintf(altzonepath, sizeof (altzonepath), "%s%s",
            md->altroot, zonepath);

        /* Add the "nosub" option to the mount options string */
        (void) strlcpy(optstr, MNTOPT_NOSUB, sizeof (optstr));

        /* Loopback mount this dataset at the altroot */
        if (mount(zonepath, altzonepath, mflag, MNTTYPE_LOFS,
            NULL, 0, optstr, sizeof (optstr)) != 0) {
                err = errno;
                be_print_err(gettext("loopback_mount_zonepath: "
                    "failed to loopback mount %s at %s: %s\n"),
                    zonepath, altzonepath, strerror(err));
                ret = BE_ERR_MOUNT;
                goto done;
        }
        ret = BE_SUCCESS;

done :
        (void) fclose(fp);
        return (ret);
}

/*
 * Function:    unmount_shared_fs
 * Description: This function iterates through the mnttab and finds all
 *              loopback mount entries that reside within the altroot of
 *              where the BE is mounted, and unmounts it.
 * Parameters:
 *              ud - be_unmount_data_t pointer
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
unmount_shared_fs(be_unmount_data_t *ud)
{
        FILE            *fp = NULL;
        struct mnttab   *table = NULL;
        struct mnttab   ent;
        struct mnttab   *entp = NULL;
        size_t          size = 0;
        int             read_chunk = 32;
        int             i;
        int             altroot_len;
        int             err = 0;

        errno = 0;

        /* Read in the mnttab into a table */
        if ((fp = fopen(MNTTAB, "r")) == NULL) {
                err = errno;
                be_print_err(gettext("unmount_shared_fs: "
                    "failed to open mnttab\n"));
                return (errno_to_be_err(err));
        }

        while (getmntent(fp, &ent) == 0) {
                if (size % read_chunk == 0) {
                        table = (struct mnttab *)realloc(table,
                            (size + read_chunk) * sizeof (ent));
                }
                entp = &table[size++];

                /*
                 * Copy over the current mnttab entry into our table,
                 * copying only the fields that we care about.
                 */
                (void) memset(entp, 0, sizeof (*entp));
                if ((entp->mnt_mountp = strdup(ent.mnt_mountp)) == NULL ||
                    (entp->mnt_fstype = strdup(ent.mnt_fstype)) == NULL) {
                        be_print_err(gettext("unmount_shared_fs: "
                            "memory allocation failed\n"));
                        return (BE_ERR_NOMEM);
                }
        }
        (void) fclose(fp);

        /*
         * Process the mnttab entries in reverse order, looking for
         * loopback mount entries mounted under our altroot.
         */
        altroot_len = strlen(ud->altroot);
        for (i = size; i > 0; i--) {
                entp = &table[i - 1];

                /* If not of type lofs, skip */
                if (strcmp(entp->mnt_fstype, MNTTYPE_LOFS) != 0)
                        continue;

                /* If inside the altroot, unmount it */
                if (strncmp(entp->mnt_mountp, ud->altroot, altroot_len) == 0 &&
                    entp->mnt_mountp[altroot_len] == '/') {
                        if (umount(entp->mnt_mountp) != 0) {
                                err = errno;
                                if (err == EBUSY) {
                                        (void) sleep(1);
                                        err = errno = 0;
                                        if (umount(entp->mnt_mountp) != 0)
                                                err = errno;
                                }
                                if (err != 0) {
                                        be_print_err(gettext(
                                            "unmount_shared_fs: "
                                            "failed to unmount shared file "
                                            "system %s: %s\n"),
                                            entp->mnt_mountp, strerror(err));
                                        return (errno_to_be_err(err));
                                }
                        }
                }
        }

        return (BE_SUCCESS);
}

/*
 * Function:    get_mountpoint_from_vfstab
 * Description: This function digs into the vfstab in the given altroot,
 *              and searches for an entry for the fs passed in.  If found,
 *              it returns the mountpoint of that fs in the mountpoint
 *              buffer passed in.  If the get_alt_mountpoint flag is set,
 *              it returns the mountpoint with the altroot prepended.
 * Parameters:
 *              altroot - pointer to the alternate root location
 *              fs - pointer to the file system name to look for in the
 *                      vfstab in altroot
 *              mountpoint - pointer to buffer of where the mountpoint of
 *                      fs will be returned.
 *              size_mp - size of mountpoint argument
 *              get_alt_mountpoint - flag to indicate whether or not the
 *                      mountpoint should be populated with the altroot
 *                      prepended.
 * Returns:
 *              BE_SUCCESS - Success
 *              1 - Failure
 * Scope:
 *              Private
 */
static int
get_mountpoint_from_vfstab(char *altroot, const char *fs, char *mountpoint,
    size_t size_mp, boolean_t get_alt_mountpoint)
{
        struct vfstab   vp;
        FILE            *fp = NULL;
        char            alt_vfstab[MAXPATHLEN];

        /* Generate path to alternate root vfstab */
        (void) snprintf(alt_vfstab, sizeof (alt_vfstab), "%s/etc/vfstab",
            altroot);

        /* Open alternate root vfstab */
        if ((fp = fopen(alt_vfstab, "r")) == NULL) {
                be_print_err(gettext("get_mountpoint_from_vfstab: "
                    "failed to open vfstab (%s)\n"), alt_vfstab);
                return (1);
        }

        if (getvfsspec(fp, &vp, (char *)fs) == 0) {
                /*
                 * Found entry for fs, grab its mountpoint.
                 * If the flag to prepend the altroot into the mountpoint
                 * is set, prepend it.  Otherwise, just return the mountpoint.
                 */
                if (get_alt_mountpoint) {
                        (void) snprintf(mountpoint, size_mp, "%s%s", altroot,
                            vp.vfs_mountp);
                } else {
                        (void) strlcpy(mountpoint, vp.vfs_mountp, size_mp);
                }
        } else {
                (void) fclose(fp);
                return (1);
        }

        (void) fclose(fp);

        return (BE_SUCCESS);
}

/*
 * Function:    fix_mountpoint_callback
 * Description: This callback function is used to iterate through a BE's
 *              children filesystems to check if its mountpoint is currently
 *              set to be mounted at some specified altroot.  If so, fix it by
 *              removing altroot from the beginning of its mountpoint.
 *
 *              Note - There's no way to tell if a child filesystem's
 *              mountpoint isn't broken, and just happens to begin with
 *              the altroot we're looking for.  In this case, this function
 *              will errantly remove the altroot portion from the beginning
 *              of this filesystem's mountpoint.
 *
 * Parameters:
 *              zhp - zfs_handle_t pointer to filesystem being processed.
 *              data - altroot of where BE is to be mounted.
 * Returns:
 *              0 - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
fix_mountpoint_callback(zfs_handle_t *zhp, void *data)
{
        zprop_source_t  sourcetype;
        char            source[ZFS_MAXNAMELEN];
        char            mountpoint[MAXPATHLEN];
        char            *zhp_mountpoint = NULL;
        char            *altroot = data;
        int             ret = 0;

        /* Get dataset's mountpoint and source values */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), &sourcetype, source, sizeof (source),
            B_FALSE) != 0) {
                be_print_err(gettext("fix_mountpoint_callback: "
                    "failed to get mountpoint and sourcetype for %s\n"),
                    zfs_get_name(zhp));
                ZFS_CLOSE(zhp);
                return (BE_ERR_ZFS);
        }

        /*
         * If the mountpoint is not inherited and the mountpoint is not
         * 'legacy', this file system potentially needs its mountpoint
         * fixed.
         */
        if (!(sourcetype & ZPROP_SRC_INHERITED) &&
            strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) != 0) {

                /*
                 * Check if this file system's current mountpoint is
                 * under the altroot we're fixing it against.
                 */
                if (strncmp(mountpoint, altroot, strlen(altroot)) == 0 &&
                    mountpoint[strlen(altroot)] == '/') {

                        /*
                         * Get this dataset's mountpoint relative to the
                         * altroot.
                         */
                        zhp_mountpoint = mountpoint + strlen(altroot);

                        /* Fix this dataset's mountpoint value */
                        if (zfs_prop_set(zhp,
                            zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                            zhp_mountpoint)) {
                                be_print_err(gettext("fix_mountpoint_callback: "
                                    "failed to set mountpoint for %s to "
                                    "%s: %s\n"), zfs_get_name(zhp),
                                    zhp_mountpoint,
                                    libzfs_error_description(g_zfs));
                                ret = zfs_err_to_be_err(g_zfs);
                                ZFS_CLOSE(zhp);
                                return (ret);
                        }
                }
        }

        /* Iterate through this dataset's children and fix them */
        if ((ret = zfs_iter_filesystems(zhp, fix_mountpoint_callback,
            altroot)) != 0) {
                ZFS_CLOSE(zhp);
                return (ret);
        }


        ZFS_CLOSE(zhp);
        return (0);
}

/*
 * Function:    be_mount_root
 * Description: This function mounts the root dataset of a BE at the
 *              specified altroot.
 * Parameters:
 *              zhp - zfs_handle_t pointer to root dataset of a BE that is
 *              to be mounted at altroot.
 *              altroot - location of where to mount the BE root.
 * Return:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_mount_root(zfs_handle_t *zhp, char *altroot)
{
        char            mountpoint[MAXPATHLEN];

        /* Get mountpoint property of dataset */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                be_print_err(gettext("be_mount_root: failed to "
                    "get mountpoint property for %s: %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /*
         * Set the canmount property for the BE's root dataset to 'noauto' just
         * in case it's been set to 'on'.  We do this so that when we change its
         * mountpoint, zfs won't immediately try to mount it.
         */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_CANMOUNT), "noauto")
            != 0) {
                be_print_err(gettext("be_mount_root: failed to "
                    "set canmount property to 'noauto' (%s): %s\n"),
                    zfs_get_name(zhp), libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Set mountpoint for BE's root filesystem */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_MOUNTPOINT), altroot)
            != 0) {
                be_print_err(gettext("be_mount_root: failed to "
                    "set mountpoint of %s to %s: %s\n"),
                    zfs_get_name(zhp), altroot,
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Mount the BE's root filesystem */
        if (zfs_mount(zhp, NULL, 0) != 0) {
                be_print_err(gettext("be_mount_root: failed to "
                    "mount dataset %s at %s: %s\n"), zfs_get_name(zhp),
                    altroot, libzfs_error_description(g_zfs));
                /*
                 * Set this BE's root filesystem 'mountpoint' property
                 * back to what it was before.
                 */
                (void) zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
                    mountpoint);
                return (zfs_err_to_be_err(g_zfs));
        }

        return (BE_SUCCESS);
}

/*
 * Function:    be_unmount_root
 * Description: This function unmounts the root dataset of a BE, but before
 *              unmounting, it looks at the BE's vfstab to determine
 *              if the root dataset mountpoint should be left as 'legacy'
 *              or '/'.  If the vfstab contains an entry for this root
 *              dataset with a mountpoint of '/', it sets the mountpoint
 *              property to 'legacy'.
 *
 * Parameters:
 *              zhp - zfs_handle_t pointer of the BE root dataset that
 *              is currently mounted.
 *              ud - be_unmount_data_t pointer providing unmount data
 *              for the given BE root dataset.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_unmount_root(zfs_handle_t *zhp, be_unmount_data_t *ud)
{
        char            mountpoint[MAXPATHLEN];
        boolean_t       is_legacy = B_FALSE;

        /* See if this is a legacy mounted root */
        if (get_mountpoint_from_vfstab(ud->altroot, zfs_get_name(zhp),
            mountpoint, sizeof (mountpoint), B_FALSE) == BE_SUCCESS &&
            strcmp(mountpoint, "/") == 0) {
                is_legacy = B_TRUE;
        }

        /* Unmount the dataset */
        if (zfs_unmount(zhp, NULL, ud->force ? MS_FORCE : 0) != 0) {
                be_print_err(gettext("be_unmount_root: failed to "
                    "unmount BE root dataset %s: %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Set canmount property for this BE's root filesystem to noauto */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_CANMOUNT), "noauto")
            != 0) {
                be_print_err(gettext("be_unmount_root: failed to "
                    "set canmount property for %s to 'noauto': %s\n"),
                    zfs_get_name(zhp), libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /*
         * Set mountpoint for BE's root dataset back to '/', or 'legacy'
         * if its a legacy mounted root.
         */
        if (zfs_prop_set(zhp, zfs_prop_to_name(ZFS_PROP_MOUNTPOINT),
            is_legacy ? ZFS_MOUNTPOINT_LEGACY : "/") != 0) {
                be_print_err(gettext("be_unmount_root: failed to "
                    "set mountpoint of %s to %s\n"), zfs_get_name(zhp),
                    is_legacy ? ZFS_MOUNTPOINT_LEGACY : "/");
                return (zfs_err_to_be_err(g_zfs));
        }

        return (BE_SUCCESS);
}

/*
 * Function:    fix_mountpoint
 * Description: This function checks the mountpoint of an unmounted BE to make
 *              sure that it is set to either 'legacy' or '/'.  If it's not,
 *              then we're in a situation where an unmounted BE has some random
 *              mountpoint set for it.  (This could happen if the system was
 *              rebooted while an inactive BE was mounted).  This function
 *              attempts to fix its mountpoints.
 * Parameters:
 *              zhp - zfs_handle_t pointer to root dataset of the BE
 *              whose mountpoint needs to be checked.
 * Return:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
fix_mountpoint(zfs_handle_t *zhp)
{
        be_unmount_data_t       ud = { 0 };
        char    *altroot = NULL;
        char    mountpoint[MAXPATHLEN];
        int     ret = BE_SUCCESS;

        /*
         * Record what this BE's root dataset mountpoint property is currently
         * set to.
         */
        if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                be_print_err(gettext("fix_mountpoint: failed to get "
                    "mountpoint property of (%s): %s\n"), zfs_get_name(zhp),
                    libzfs_error_description(g_zfs));
                return (BE_ERR_ZFS);
        }

        /*
         * If the root dataset mountpoint is set to 'legacy' or '/', we're okay.
         */
        if (strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0 ||
            strcmp(mountpoint, "/") == 0) {
                return (BE_SUCCESS);
        }

        /*
         * Iterate through this BE's children datasets and fix
         * them if they need fixing.
         */
        if (zfs_iter_filesystems(zhp, fix_mountpoint_callback, mountpoint)
            != 0) {
                return (BE_ERR_ZFS);
        }

        /*
         * The process of mounting and unmounting the root file system
         * will fix its mountpoint to correctly be either 'legacy' or '/'
         * since be_unmount_root will do the right thing by looking at
         * its vfstab.
         */

        /* Generate temporary altroot to mount the root file system */
        if ((ret = be_make_tmp_mountpoint(&altroot)) != BE_SUCCESS) {
                be_print_err(gettext("fix_mountpoint: failed to "
                    "make temporary mountpoint\n"));
                return (ret);
        }

        /* Mount and unmount the root. */
        if ((ret = be_mount_root(zhp, altroot)) != BE_SUCCESS) {
                be_print_err(gettext("fix_mountpoint: failed to "
                    "mount BE root file system\n"));
                goto cleanup;
        }
        ud.altroot = altroot;
        if ((ret = be_unmount_root(zhp, &ud)) != BE_SUCCESS) {
                be_print_err(gettext("fix_mountpoint: failed to "
                    "unmount BE root file system\n"));
                goto cleanup;
        }

cleanup:
        free(altroot);

        return (ret);
}

/*
 * Function:    be_mount_zones
 * Description: This function finds all supported non-global zones in the
 *              given global BE and mounts them with respect to where the
 *              global BE is currently mounted.  The global BE datasets
 *              (including its shared datasets) are expected to already
 *              be mounted.
 * Parameters:
 *              be_zhp - zfs_handle_t pointer to the root dataset of the
 *                      global BE.
 *              md - be_mount_data_t pointer to data for global BE.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_mount_zones(zfs_handle_t *be_zhp, be_mount_data_t *md)
{
        zoneBrandList_t *brands = NULL;
        zoneList_t      zlst = NULL;
        char            *zonename = NULL;
        char            *zonepath = NULL;
        char            *zonepath_ds = NULL;
        int             k;
        int             ret = BE_SUCCESS;

        z_set_zone_root(md->altroot);

        if ((brands = be_get_supported_brandlist()) == NULL) {
                be_print_err(gettext("be_mount_zones: "
                    "no supported brands\n"));
                return (BE_SUCCESS);
        }

        zlst = z_get_nonglobal_zone_list_by_brand(brands);
        if (zlst == NULL) {
                z_free_brand_list(brands);
                return (BE_SUCCESS);
        }

        for (k = 0; (zonename = z_zlist_get_zonename(zlst, k)) != NULL; k++) {
                if (z_zlist_get_current_state(zlst, k) ==
                    ZONE_STATE_INSTALLED) {
                        zonepath = z_zlist_get_zonepath(zlst, k);

                        /*
                         * Get the dataset of this zonepath in current BE.
                         * If its not a dataset, skip it.
                         */
                        if ((zonepath_ds = be_get_ds_from_dir(zonepath))
                            == NULL)
                                continue;

                        /*
                         * Check if this zone is supported based on
                         * the dataset of its zonepath
                         */
                        if (!be_zone_supported(zonepath_ds)) {
                                free(zonepath_ds);
                                zonepath_ds = NULL;
                                continue;
                        }

                        /*
                         * if BE's shared file systems are already mounted,
                         * zone path dataset would have already been lofs
                         * mounted under altroot. Otherwise, we need to do
                         * it here.
                         */
                        if (!md->shared_fs) {
                                ret = loopback_mount_zonepath(zonepath, md);
                                if (ret != BE_SUCCESS)
                                        goto done;
                        }


                        /* Mount this zone */
                        ret = be_mount_one_zone(be_zhp, md, zonename,
                            zonepath, zonepath_ds);

                        free(zonepath_ds);
                        zonepath_ds = NULL;

                        if (ret != BE_SUCCESS) {
                                be_print_err(gettext("be_mount_zones: "
                                    "failed to mount zone %s under "
                                    "altroot %s\n"), zonename, md->altroot);
                                goto done;
                        }
                }
        }

done:
        z_free_brand_list(brands);
        z_free_zone_list(zlst);
        /*
         * libinstzones caches mnttab and uses cached version for resolving lofs
         * mounts when we call z_resolve_lofs. It creates the cached version
         * when the first call to z_resolve_lofs happens. So, library's cached
         * mnttab doesn't contain entries for lofs mounts created in the above
         * loop. Because of this, subsequent calls to z_resolve_lofs would fail
         * to resolve these lofs mounts. So, here we destroy library's cached
         * mnttab to force its recreation when the next call to z_resolve_lofs
         * happens.
         */
        z_destroyMountTable();
        return (ret);
}

/*
 * Function:    be_unmount_zones
 * Description: This function finds all supported non-global zones in the
 *              given mounted global BE and unmounts them.
 * Parameters:
 *              ud - unmount_data_t pointer data for the global BE.
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_unmount_zones(be_unmount_data_t *ud)
{
        zoneBrandList_t         *brands = NULL;
        zoneList_t              zlst = NULL;
        char                    *zonename = NULL;
        char                    *zonepath = NULL;
        char                    alt_zonepath[MAXPATHLEN];
        char                    *zonepath_ds = NULL;
        int                     k;
        int                     ret = BE_SUCCESS;

        z_set_zone_root(ud->altroot);

        if ((brands = be_get_supported_brandlist()) == NULL) {
                be_print_err(gettext("be_unmount_zones: "
                    "no supported brands\n"));
                return (BE_SUCCESS);
        }

        zlst = z_get_nonglobal_zone_list_by_brand(brands);
        if (zlst == NULL) {
                z_free_brand_list(brands);
                return (BE_SUCCESS);
        }

        for (k = 0; (zonename = z_zlist_get_zonename(zlst, k)) != NULL; k++) {
                if (z_zlist_get_current_state(zlst, k) ==
                    ZONE_STATE_INSTALLED) {
                        zonepath = z_zlist_get_zonepath(zlst, k);

                        /* Build zone's zonepath wrt the global BE altroot */
                        (void) snprintf(alt_zonepath, sizeof (alt_zonepath),
                            "%s%s", ud->altroot, zonepath);

                        /*
                         * Get the dataset of this zonepath.  If its not
                         * a dataset, skip it.
                         */
                        if ((zonepath_ds = be_get_ds_from_dir(alt_zonepath))
                            == NULL)
                                continue;

                        /*
                         * Check if this zone is supported based on the
                         * dataset of its zonepath.
                         */
                        if (!be_zone_supported(zonepath_ds)) {
                                free(zonepath_ds);
                                zonepath_ds = NULL;
                                continue;
                        }

                        /* Unmount this zone */
                        ret = be_unmount_one_zone(ud, zonename, zonepath,
                            zonepath_ds);

                        free(zonepath_ds);
                        zonepath_ds = NULL;

                        if (ret != BE_SUCCESS) {
                                be_print_err(gettext("be_unmount_zones:"
                                    " failed to unmount zone %s from "
                                    "altroot %s\n"), zonename, ud->altroot);
                                goto done;
                        }
                }
        }

done:
        z_free_brand_list(brands);
        z_free_zone_list(zlst);
        return (ret);
}

/*
 * Function:    be_mount_one_zone
 * Description: This function is called to mount one zone for a given
 *              global BE.
 * Parameters:
 *              be_zhp - zfs_handle_t pointer to the root dataset of the
 *                      global BE
 *              md - be_mount_data_t pointer to data for global BE
 *              zonename - name of zone to mount
 *              zonepath - zonepath of zone to mount
 *              zonepath_ds - dataset for the zonepath
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_mount_one_zone(zfs_handle_t *be_zhp, be_mount_data_t *md, char *zonename,
    char *zonepath, char *zonepath_ds)
{
        be_mount_data_t zone_md = { 0 };
        zfs_handle_t    *zone_zhp = NULL;
        char            zone_altroot[MAXPATHLEN];
        char            zoneroot[MAXPATHLEN];
        char            zoneroot_ds[MAXPATHLEN];
        int             ret = BE_SUCCESS;

        /* Find the active zone root dataset for this zone for this BE */
        if ((ret = be_find_active_zone_root(be_zhp, zonepath_ds, zoneroot_ds,
            sizeof (zoneroot_ds))) == BE_ERR_ZONE_NO_ACTIVE_ROOT) {
                be_print_err(gettext("be_mount_one_zone: did not "
                    "find active zone root for zone %s, skipping ...\n"),
                    zonename);
                return (BE_SUCCESS);
        } else if (ret != BE_SUCCESS) {
                be_print_err(gettext("be_mount_one_zone: failed to "
                    "find active zone root for zone %s\n"), zonename);
                return (ret);
        }

        /* Get handle to active zoneroot dataset */
        if ((zone_zhp = zfs_open(g_zfs, zoneroot_ds, ZFS_TYPE_FILESYSTEM))
            == NULL) {
                be_print_err(gettext("be_mount_one_zone: failed to "
                    "open zone root dataset (%s): %s\n"), zoneroot_ds,
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* Generate string for zone's altroot path */
        be_make_zoneroot(zonepath, zoneroot, sizeof (zoneroot));
        (void) strlcpy(zone_altroot, md->altroot, sizeof (zone_altroot));
        (void) strlcat(zone_altroot, zoneroot, sizeof (zone_altroot));

        /* Build mount_data for the zone */
        zone_md.altroot = zone_altroot;
        zone_md.shared_fs = md->shared_fs;
        zone_md.shared_rw = md->shared_rw;

        /* Mount the zone's root file system */
        if ((ret = be_mount_zone_root(zone_zhp, &zone_md)) != BE_SUCCESS) {
                be_print_err(gettext("be_mount_one_zone: failed to "
                    "mount zone root file system at %s\n"), zone_altroot);
                goto done;
        }

        /* Iterate through zone's children filesystems */
        if ((ret = zfs_iter_filesystems(zone_zhp, be_mount_callback,
            zone_altroot)) != 0) {
                be_print_err(gettext("be_mount_one_zone: failed to "
                    "mount zone subordinate file systems at %s\n"),
                    zone_altroot);
                goto done;
        }

        /* TODO: Mount all shared file systems for this zone */

done:
        ZFS_CLOSE(zone_zhp);
        return (ret);
}

/*
 * Function:    be_unmount_one_zone
 * Description: This function unmount one zone for a give global BE.
 * Parameters:
 *              ud - be_unmount_data_t pointer to data for global BE
 *              zonename - name of zone to unmount
 *              zonepath - zonepath of the zone to unmount
 *              zonepath_ds - dataset for the zonepath
 * Returns:
 *              BE_SUCCESS - Success
 *              be_errno_t - Failure
 * Scope:
 *              Private
 */
static int
be_unmount_one_zone(be_unmount_data_t *ud, char *zonename, char *zonepath,
    char *zonepath_ds)
{
        be_unmount_data_t       zone_ud = { 0 };
        zfs_handle_t    *zone_zhp = NULL;
        char            zone_altroot[MAXPATHLEN];
        char            zoneroot[MAXPATHLEN];
        char            zoneroot_ds[MAXPATHLEN];
        int             ret = BE_SUCCESS;

        /* Generate string for zone's alternate root path */
        be_make_zoneroot(zonepath, zoneroot, sizeof (zoneroot));
        (void) strlcpy(zone_altroot, ud->altroot, sizeof (zone_altroot));
        (void) strlcat(zone_altroot, zoneroot, sizeof (zone_altroot));

        /* Build be_unmount_data for zone */
        zone_ud.altroot = zone_altroot;
        zone_ud.force = ud->force;

        /* Find the mounted zone root dataset for this zone for this BE */
        if ((ret = be_find_mounted_zone_root(zone_altroot, zonepath_ds,
            zoneroot_ds, sizeof (zoneroot_ds))) == BE_ERR_NO_MOUNTED_ZONE) {
                be_print_err(gettext("be_unmount_one_zone: did not "
                    "find any zone root mounted for zone %s\n"), zonename);
                return (BE_SUCCESS);
        } else if (ret != BE_SUCCESS) {
                be_print_err(gettext("be_unmount_one_zone: failed to "
                    "find mounted zone root for zone %s\n"), zonename);
                return (ret);
        }

        /* Get handle to zoneroot dataset mounted for this BE */
        if ((zone_zhp = zfs_open(g_zfs, zoneroot_ds, ZFS_TYPE_FILESYSTEM))
            == NULL) {
                be_print_err(gettext("be_unmount_one_zone: failed to "
                    "open mounted zone root dataset (%s): %s\n"), zoneroot_ds,
                    libzfs_error_description(g_zfs));
                return (zfs_err_to_be_err(g_zfs));
        }

        /* TODO: Unmount all shared file systems for this zone */

        /* Iterate through zone's children filesystems and unmount them */
        if ((ret = zfs_iter_filesystems(zone_zhp, be_unmount_callback,
            &zone_ud)) != 0) {
                be_print_err(gettext("be_unmount_one_zone: failed to "
                    "unmount zone subordinate file systems at %s\n"),
                    zone_altroot);
                goto done;
        }

        /* Unmount the zone's root filesystem */
        if ((ret = be_unmount_zone_root(zone_zhp, &zone_ud)) != BE_SUCCESS) {
                be_print_err(gettext("be_unmount_one_zone: failed to "
                    "unmount zone root file system at %s\n"), zone_altroot);
                goto done;
        }

done:
        ZFS_CLOSE(zone_zhp);
        return (ret);
}

/*
 * Function:    be_get_ds_from_dir_callback
 * Description: This is a callback function used to iterate all datasets
 *              to find the one that is currently mounted at the directory
 *              being searched for.  If matched, the name of the dataset is
 *              returned in heap storage, so the caller is responsible for
 *              freeing it.
 * Parameters:
 *              zhp - zfs_handle_t pointer to current dataset being processed.
 *              data - dir_data_t pointer providing name of directory being
 *                      searched for.
 * Returns:
 *              1 - This dataset is mounted at directory being searched for.
 *              0 - This dataset is not mounted at directory being searched for.
 * Scope:
 *              Private
 */
static int
be_get_ds_from_dir_callback(zfs_handle_t *zhp, void *data)
{
        dir_data_t      *dd = data;
        char            *mp = NULL;
        int             zret = 0;

        if (zfs_get_type(zhp) != ZFS_TYPE_FILESYSTEM) {
                ZFS_CLOSE(zhp);
                return (0);
        }

        if (zfs_is_mounted(zhp, &mp) && mp != NULL &&
            strcmp(mp, dd->dir) == 0) {
                if ((dd->ds = strdup(zfs_get_name(zhp))) == NULL) {
                        be_print_err(gettext("be_get_ds_from_dir_callback: "
                            "memory allocation failed\n"));
                        ZFS_CLOSE(zhp);
                        return (0);
                }
                ZFS_CLOSE(zhp);
                return (1);
        }

        zret = zfs_iter_filesystems(zhp, be_get_ds_from_dir_callback, dd);

        ZFS_CLOSE(zhp);

        return (zret);
}