/*
 * 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2013 by Delphix. All rights reserved.
 * Copyright 2020 Tintri by DDN, Inc. All rights reserved.
 * Copyright 2019-2024 RackTop Systems, Inc.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/resource.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/sid.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/errno.h>
#include <sys/unistd.h>
#include <sys/sdt.h>
#include <sys/fs/zfs.h>
#include <sys/mode.h>
#include <sys/policy.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_fuid.h>
#include <sys/zfs_acl.h>
#include <sys/zfs_dir.h>
#include <sys/zfs_vfsops.h>
#include <sys/dmu.h>
#include <sys/dnode.h>
#include <sys/zap.h>
#include <sys/sa.h>
#include "fs/fs_subr.h"
#include <acl/acl_common.h>

#define ALLOW   ACE_ACCESS_ALLOWED_ACE_TYPE
#define DENY    ACE_ACCESS_DENIED_ACE_TYPE
#define MAX_ACE_TYPE    ACE_SYSTEM_ALARM_CALLBACK_OBJECT_ACE_TYPE
#define MIN_ACE_TYPE    ALLOW

#define OWNING_GROUP            (ACE_GROUP|ACE_IDENTIFIER_GROUP)
#define EVERYONE_ALLOW_MASK (ACE_READ_ACL|ACE_READ_ATTRIBUTES | \
    ACE_READ_NAMED_ATTRS|ACE_SYNCHRONIZE)
#define EVERYONE_DENY_MASK (ACE_WRITE_ACL|ACE_WRITE_OWNER | \
    ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)
#define OWNER_ALLOW_MASK (ACE_WRITE_ACL | ACE_WRITE_OWNER | \
    ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)

#define ZFS_CHECKED_MASKS (ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_DATA| \
    ACE_READ_NAMED_ATTRS|ACE_WRITE_DATA|ACE_WRITE_ATTRIBUTES| \
    ACE_WRITE_NAMED_ATTRS|ACE_APPEND_DATA|ACE_EXECUTE|ACE_WRITE_OWNER| \
    ACE_WRITE_ACL|ACE_DELETE|ACE_DELETE_CHILD|ACE_SYNCHRONIZE)

#define WRITE_MASK_DATA (ACE_WRITE_DATA|ACE_APPEND_DATA|ACE_WRITE_NAMED_ATTRS)
#define WRITE_MASK_ATTRS (ACE_WRITE_ACL|ACE_WRITE_OWNER|ACE_WRITE_ATTRIBUTES| \
    ACE_DELETE|ACE_DELETE_CHILD)
#define WRITE_MASK (WRITE_MASK_DATA|WRITE_MASK_ATTRS)

#define OGE_CLEAR       (ACE_READ_DATA|ACE_LIST_DIRECTORY|ACE_WRITE_DATA| \
    ACE_ADD_FILE|ACE_APPEND_DATA|ACE_ADD_SUBDIRECTORY|ACE_EXECUTE)

#define OKAY_MASK_BITS (ACE_READ_DATA|ACE_LIST_DIRECTORY|ACE_WRITE_DATA| \
    ACE_ADD_FILE|ACE_APPEND_DATA|ACE_ADD_SUBDIRECTORY|ACE_EXECUTE)

#define ALL_INHERIT     (ACE_FILE_INHERIT_ACE|ACE_DIRECTORY_INHERIT_ACE | \
    ACE_NO_PROPAGATE_INHERIT_ACE|ACE_INHERIT_ONLY_ACE|ACE_INHERITED_ACE)

#define RESTRICTED_CLEAR        (ACE_WRITE_ACL|ACE_WRITE_OWNER)

#define V4_ACL_WIDE_FLAGS (ZFS_ACL_AUTO_INHERIT|ZFS_ACL_DEFAULTED|\
    ZFS_ACL_PROTECTED)

#define ZFS_ACL_WIDE_FLAGS (V4_ACL_WIDE_FLAGS|ZFS_ACL_TRIVIAL|ZFS_INHERIT_ACE|\
    ZFS_ACL_OBJ_ACE)

#define ALL_MODE_EXECS (S_IXUSR | S_IXGRP | S_IXOTH)

typedef struct zfs_acl_iter {
        zfs_acl_t       *zai_aclp;      /* The ACL we're iterating */
        zfs_acl_node_t  *zai_curr_node; /* current node iterator is in */
        void            *zai_next_ace;  /* pointer to next ACE */
        int             zai_ace_idx;    /* ace iterator positioned on */
} zfs_acl_iter_t;

static uint16_t
zfs_ace_v0_get_type(void *acep)
{
        return (((zfs_oldace_t *)acep)->z_type);
}

static uint16_t
zfs_ace_v0_get_flags(void *acep)
{
        return (((zfs_oldace_t *)acep)->z_flags);
}

static uint32_t
zfs_ace_v0_get_mask(void *acep)
{
        return (((zfs_oldace_t *)acep)->z_access_mask);
}

static uint64_t
zfs_ace_v0_get_who(void *acep)
{
        return (((zfs_oldace_t *)acep)->z_fuid);
}

static void
zfs_ace_v0_set_type(void *acep, uint16_t type)
{
        ((zfs_oldace_t *)acep)->z_type = type;
}

static void
zfs_ace_v0_set_flags(void *acep, uint16_t flags)
{
        ((zfs_oldace_t *)acep)->z_flags = flags;
}

static void
zfs_ace_v0_set_mask(void *acep, uint32_t mask)
{
        ((zfs_oldace_t *)acep)->z_access_mask = mask;
}

static void
zfs_ace_v0_set_who(void *acep, uint64_t who)
{
        ((zfs_oldace_t *)acep)->z_fuid = who;
}

/*ARGSUSED*/
static size_t
zfs_ace_v0_size(void *acep)
{
        return (sizeof (zfs_oldace_t));
}

static size_t
zfs_ace_v0_abstract_size(void)
{
        return (sizeof (zfs_oldace_t));
}

static int
zfs_ace_v0_mask_off(void)
{
        return (offsetof(zfs_oldace_t, z_access_mask));
}

/*ARGSUSED*/
static int
zfs_ace_v0_data(void *acep, void **datap)
{
        *datap = NULL;
        return (0);
}

static acl_ops_t zfs_acl_v0_ops = {
        zfs_ace_v0_get_mask,
        zfs_ace_v0_set_mask,
        zfs_ace_v0_get_flags,
        zfs_ace_v0_set_flags,
        zfs_ace_v0_get_type,
        zfs_ace_v0_set_type,
        zfs_ace_v0_get_who,
        zfs_ace_v0_set_who,
        zfs_ace_v0_size,
        zfs_ace_v0_abstract_size,
        zfs_ace_v0_mask_off,
        zfs_ace_v0_data
};

static uint16_t
zfs_ace_fuid_get_type(void *acep)
{
        return (((zfs_ace_hdr_t *)acep)->z_type);
}

static uint16_t
zfs_ace_fuid_get_flags(void *acep)
{
        return (((zfs_ace_hdr_t *)acep)->z_flags);
}

static uint32_t
zfs_ace_fuid_get_mask(void *acep)
{
        return (((zfs_ace_hdr_t *)acep)->z_access_mask);
}

static uint64_t
zfs_ace_fuid_get_who(void *args)
{
        uint16_t entry_type;
        zfs_ace_t *acep = args;

        entry_type = acep->z_hdr.z_flags & ACE_TYPE_FLAGS;

        if (entry_type == ACE_OWNER || entry_type == OWNING_GROUP ||
            entry_type == ACE_EVERYONE)
                return (-1);
        return (((zfs_ace_t *)acep)->z_fuid);
}

static void
zfs_ace_fuid_set_type(void *acep, uint16_t type)
{
        ((zfs_ace_hdr_t *)acep)->z_type = type;
}

static void
zfs_ace_fuid_set_flags(void *acep, uint16_t flags)
{
        ((zfs_ace_hdr_t *)acep)->z_flags = flags;
}

static void
zfs_ace_fuid_set_mask(void *acep, uint32_t mask)
{
        ((zfs_ace_hdr_t *)acep)->z_access_mask = mask;
}

static void
zfs_ace_fuid_set_who(void *arg, uint64_t who)
{
        zfs_ace_t *acep = arg;

        uint16_t entry_type = acep->z_hdr.z_flags & ACE_TYPE_FLAGS;

        if (entry_type == ACE_OWNER || entry_type == OWNING_GROUP ||
            entry_type == ACE_EVERYONE)
                return;
        acep->z_fuid = who;
}

static size_t
zfs_ace_fuid_size(void *acep)
{
        zfs_ace_hdr_t *zacep = acep;
        uint16_t entry_type;

        switch (zacep->z_type) {
        case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
        case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                return (sizeof (zfs_object_ace_t));
        case ALLOW:
        case DENY:
                entry_type =
                    (((zfs_ace_hdr_t *)acep)->z_flags & ACE_TYPE_FLAGS);
                if (entry_type == ACE_OWNER ||
                    entry_type == OWNING_GROUP ||
                    entry_type == ACE_EVERYONE)
                        return (sizeof (zfs_ace_hdr_t));
                /*FALLTHROUGH*/
        default:
                return (sizeof (zfs_ace_t));
        }
}

static size_t
zfs_ace_fuid_abstract_size(void)
{
        return (sizeof (zfs_ace_hdr_t));
}

static int
zfs_ace_fuid_mask_off(void)
{
        return (offsetof(zfs_ace_hdr_t, z_access_mask));
}

static int
zfs_ace_fuid_data(void *acep, void **datap)
{
        zfs_ace_t *zacep = acep;
        zfs_object_ace_t *zobjp;

        switch (zacep->z_hdr.z_type) {
        case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
        case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                zobjp = acep;
                *datap = (caddr_t)zobjp + sizeof (zfs_ace_t);
                return (sizeof (zfs_object_ace_t) - sizeof (zfs_ace_t));
        default:
                *datap = NULL;
                return (0);
        }
}

static acl_ops_t zfs_acl_fuid_ops = {
        zfs_ace_fuid_get_mask,
        zfs_ace_fuid_set_mask,
        zfs_ace_fuid_get_flags,
        zfs_ace_fuid_set_flags,
        zfs_ace_fuid_get_type,
        zfs_ace_fuid_set_type,
        zfs_ace_fuid_get_who,
        zfs_ace_fuid_set_who,
        zfs_ace_fuid_size,
        zfs_ace_fuid_abstract_size,
        zfs_ace_fuid_mask_off,
        zfs_ace_fuid_data
};

/*
 * The following three functions are provided for compatibility with
 * older ZPL version in order to determine if the file use to have
 * an external ACL and what version of ACL previously existed on the
 * file.  Would really be nice to not need this, sigh.
 */
uint64_t
zfs_external_acl(znode_t *zp)
{
        zfs_acl_phys_t acl_phys;
        int error;

        if (zp->z_is_sa)
                return (0);

        /*
         * Need to deal with a potential
         * race where zfs_sa_upgrade could cause
         * z_isa_sa to change.
         *
         * If the lookup fails then the state of z_is_sa should have
         * changed.
         */

        if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_ZNODE_ACL(zp->z_zfsvfs),
            &acl_phys, sizeof (acl_phys))) == 0)
                return (acl_phys.z_acl_extern_obj);
        else {
                /*
                 * after upgrade the SA_ZPL_ZNODE_ACL should have been
                 * removed
                 */
                VERIFY(zp->z_is_sa && error == ENOENT);
                return (0);
        }
}

/*
 * Determine size of ACL in bytes
 *
 * This is more complicated than it should be since we have to deal
 * with old external ACLs.
 */
static int
zfs_acl_znode_info(znode_t *zp, int *aclsize, int *aclcount,
    zfs_acl_phys_t *aclphys)
{
        zfsvfs_t *zfsvfs = zp->z_zfsvfs;
        uint64_t acl_count;
        int size;
        int error;

        ASSERT(RW_ISWRITER(&zp->z_acl_lock));
        if (zp->z_is_sa) {
                if ((error = sa_size(zp->z_sa_hdl, SA_ZPL_DACL_ACES(zfsvfs),
                    &size)) != 0)
                        return (error);
                *aclsize = size;
                if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_DACL_COUNT(zfsvfs),
                    &acl_count, sizeof (acl_count))) != 0)
                        return (error);
                *aclcount = acl_count;
        } else {
                if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_ZNODE_ACL(zfsvfs),
                    aclphys, sizeof (*aclphys))) != 0)
                        return (error);

                if (aclphys->z_acl_version == ZFS_ACL_VERSION_INITIAL) {
                        *aclsize = ZFS_ACL_SIZE(aclphys->z_acl_size);
                        *aclcount = aclphys->z_acl_size;
                } else {
                        *aclsize = aclphys->z_acl_size;
                        *aclcount = aclphys->z_acl_count;
                }
        }
        return (0);
}

int
zfs_znode_acl_version(znode_t *zp)
{
        zfs_acl_phys_t acl_phys;

        if (zp->z_is_sa)
                return (ZFS_ACL_VERSION_FUID);
        else {
                int error;

                /*
                 * Need to deal with a potential
                 * race where zfs_sa_upgrade could cause
                 * z_isa_sa to change.
                 *
                 * If the lookup fails then the state of z_is_sa should have
                 * changed.
                 */
                if ((error = sa_lookup(zp->z_sa_hdl,
                    SA_ZPL_ZNODE_ACL(zp->z_zfsvfs),
                    &acl_phys, sizeof (acl_phys))) == 0)
                        return (acl_phys.z_acl_version);
                else {
                        /*
                         * After upgrade SA_ZPL_ZNODE_ACL should have
                         * been removed.
                         */
                        VERIFY(zp->z_is_sa && error == ENOENT);
                        return (ZFS_ACL_VERSION_FUID);
                }
        }
}

static int
zfs_acl_version(int version)
{
        if (version < ZPL_VERSION_FUID)
                return (ZFS_ACL_VERSION_INITIAL);
        else
                return (ZFS_ACL_VERSION_FUID);
}

static int
zfs_acl_version_zp(znode_t *zp)
{
        return (zfs_acl_version(zp->z_zfsvfs->z_version));
}

zfs_acl_t *
zfs_acl_alloc(int vers)
{
        zfs_acl_t *aclp;

        aclp = kmem_zalloc(sizeof (zfs_acl_t), KM_SLEEP);
        list_create(&aclp->z_acl, sizeof (zfs_acl_node_t),
            offsetof(zfs_acl_node_t, z_next));
        aclp->z_version = vers;
        if (vers == ZFS_ACL_VERSION_FUID)
                aclp->z_ops = zfs_acl_fuid_ops;
        else
                aclp->z_ops = zfs_acl_v0_ops;
        return (aclp);
}

zfs_acl_node_t *
zfs_acl_node_alloc(size_t bytes)
{
        zfs_acl_node_t *aclnode;

        aclnode = kmem_zalloc(sizeof (zfs_acl_node_t), KM_SLEEP);
        if (bytes) {
                aclnode->z_acldata = kmem_alloc(bytes, KM_SLEEP);
                aclnode->z_allocdata = aclnode->z_acldata;
                aclnode->z_allocsize = bytes;
                aclnode->z_size = bytes;
        }

        return (aclnode);
}

static void
zfs_acl_node_free(zfs_acl_node_t *aclnode)
{
        if (aclnode->z_allocsize)
                kmem_free(aclnode->z_allocdata, aclnode->z_allocsize);
        kmem_free(aclnode, sizeof (zfs_acl_node_t));
}

static void
zfs_acl_release_nodes(zfs_acl_t *aclp)
{
        zfs_acl_node_t *aclnode;

        while (aclnode = list_head(&aclp->z_acl)) {
                list_remove(&aclp->z_acl, aclnode);
                zfs_acl_node_free(aclnode);
        }
        aclp->z_acl_count = 0;
        aclp->z_acl_bytes = 0;
}

void
zfs_acl_free(zfs_acl_t *aclp)
{
        zfs_acl_release_nodes(aclp);
        list_destroy(&aclp->z_acl);
        kmem_free(aclp, sizeof (zfs_acl_t));
}

static boolean_t
zfs_acl_valid_ace_type(uint_t type, uint_t flags)
{
        uint16_t entry_type;

        switch (type) {
        case ALLOW:
        case DENY:
        case ACE_SYSTEM_AUDIT_ACE_TYPE:
        case ACE_SYSTEM_ALARM_ACE_TYPE:
                entry_type = flags & ACE_TYPE_FLAGS;
                return (entry_type == ACE_OWNER ||
                    entry_type == OWNING_GROUP ||
                    entry_type == ACE_EVERYONE || entry_type == 0 ||
                    entry_type == ACE_IDENTIFIER_GROUP);
        default:
                if (type >= MIN_ACE_TYPE && type <= MAX_ACE_TYPE)
                        return (B_TRUE);
        }
        return (B_FALSE);
}

static boolean_t
zfs_ace_valid(vtype_t obj_type, zfs_acl_t *aclp, uint16_t type, uint16_t iflags)
{
        /*
         * first check type of entry
         */

        if (!zfs_acl_valid_ace_type(type, iflags))
                return (B_FALSE);

        switch (type) {
        case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
        case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
        case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                if (aclp->z_version < ZFS_ACL_VERSION_FUID)
                        return (B_FALSE);
                aclp->z_hints |= ZFS_ACL_OBJ_ACE;
        }

        /*
         * next check inheritance level flags
         */

        if (obj_type == VDIR &&
            (iflags & (ACE_FILE_INHERIT_ACE|ACE_DIRECTORY_INHERIT_ACE)))
                aclp->z_hints |= ZFS_INHERIT_ACE;

        if (iflags & (ACE_INHERIT_ONLY_ACE|ACE_NO_PROPAGATE_INHERIT_ACE)) {
                if ((iflags & (ACE_FILE_INHERIT_ACE|
                    ACE_DIRECTORY_INHERIT_ACE)) == 0) {
                        return (B_FALSE);
                }
        }

        return (B_TRUE);
}

/*
 * We want this iterator to be usable by multiple threads in parallel.
 * Caller now passes iterator state as 1st arg.
 */
static void *
zfs_acl_next_ace(zfs_acl_iter_t *zaip, void *start, uint64_t *who,
    uint32_t *access_mask, uint16_t *iflags, uint16_t *type)
{
        zfs_acl_t *aclp = zaip->zai_aclp;
        zfs_acl_node_t *aclnode;

        ASSERT(aclp);

        if (start == NULL) {
                aclnode = list_head(&aclp->z_acl);
                if (aclnode == NULL)
                        return (NULL);

                zaip->zai_curr_node = aclnode;
                zaip->zai_next_ace = aclnode->z_acldata;
                zaip->zai_ace_idx = 0;
        }

        aclnode = zaip->zai_curr_node;

        if (aclnode == NULL)
                return (NULL);

        if (zaip->zai_ace_idx >= aclnode->z_ace_count) {
        next_node:
                aclnode = list_next(&aclp->z_acl, aclnode);
                if (aclnode == NULL)
                        return (NULL);
                zaip->zai_curr_node = aclnode;
                zaip->zai_ace_idx = 0;
                zaip->zai_next_ace = aclnode->z_acldata;
        }

        if (zaip->zai_ace_idx < aclnode->z_ace_count) {
                void *acep = zaip->zai_next_ace;
                size_t ace_size;

                /*
                 * Make sure we don't overstep our bounds
                 */
                ace_size = aclp->z_ops.ace_size(acep);

                if (((caddr_t)acep + ace_size) >
                    ((caddr_t)aclnode->z_acldata + aclnode->z_size)) {
                        DTRACE_PROBE3(acl__size__error, zfs_acl_t *, aclp,
                            zfs_acl_node_t *, aclnode, zfs_ace_hdr_t *, acep);
                        goto next_node;
                }

                *iflags = aclp->z_ops.ace_flags_get(acep);
                *type = aclp->z_ops.ace_type_get(acep);
                *access_mask = aclp->z_ops.ace_mask_get(acep);
                *who = aclp->z_ops.ace_who_get(acep);

                zaip->zai_next_ace = (caddr_t)acep + ace_size;
                zaip->zai_ace_idx++;

                return ((void *)acep);
        }
        return (NULL);
}

/*ARGSUSED*/
static uint64_t
zfs_ace_walk(void *datap, uint64_t cookie, int aclcnt,
    uint16_t *flags, uint16_t *type, uint32_t *mask)
{
        zfs_acl_iter_t *zaip = datap;
        zfs_ace_hdr_t *acep = (zfs_ace_hdr_t *)(uintptr_t)cookie;
        uint64_t who;

        acep = zfs_acl_next_ace(zaip, acep, &who, mask,
            flags, type);
        return ((uint64_t)(uintptr_t)acep);
}

/*
 * Copy ACE to internal ZFS format.
 * While processing the ACL each ACE will be validated for correctness.
 * ACE FUIDs will be created later.
 */
int
zfs_copy_ace_2_fuid(zfsvfs_t *zfsvfs, vtype_t obj_type, zfs_acl_t *aclp,
    void *datap, zfs_ace_t *z_acl, uint64_t aclcnt, size_t *size,
    zfs_fuid_info_t **fuidp, cred_t *cr)
{
        int i;
        uint16_t entry_type;
        zfs_ace_t *aceptr = z_acl;
        ace_t *acep = datap;
        zfs_object_ace_t *zobjacep;
        ace_object_t *aceobjp;

        for (i = 0; i != aclcnt; i++) {
                aceptr->z_hdr.z_access_mask = acep->a_access_mask;
                aceptr->z_hdr.z_flags = acep->a_flags;
                aceptr->z_hdr.z_type = acep->a_type;
                entry_type = aceptr->z_hdr.z_flags & ACE_TYPE_FLAGS;
                if (entry_type != ACE_OWNER && entry_type != OWNING_GROUP &&
                    entry_type != ACE_EVERYONE) {
                        aceptr->z_fuid = zfs_fuid_create(zfsvfs, acep->a_who,
                            cr, (entry_type == 0) ?
                            ZFS_ACE_USER : ZFS_ACE_GROUP, fuidp);
                }

                /*
                 * Make sure ACE is valid
                 */
                if (zfs_ace_valid(obj_type, aclp, aceptr->z_hdr.z_type,
                    aceptr->z_hdr.z_flags) != B_TRUE)
                        return (SET_ERROR(EINVAL));

                switch (acep->a_type) {
                case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
                case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
                case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
                case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                        zobjacep = (zfs_object_ace_t *)aceptr;
                        aceobjp = (ace_object_t *)acep;

                        bcopy(aceobjp->a_obj_type, zobjacep->z_object_type,
                            sizeof (aceobjp->a_obj_type));
                        bcopy(aceobjp->a_inherit_obj_type,
                            zobjacep->z_inherit_type,
                            sizeof (aceobjp->a_inherit_obj_type));
                        acep = (ace_t *)((caddr_t)acep + sizeof (ace_object_t));
                        break;
                default:
                        acep = (ace_t *)((caddr_t)acep + sizeof (ace_t));
                }

                aceptr = (zfs_ace_t *)((caddr_t)aceptr +
                    aclp->z_ops.ace_size(aceptr));
        }

        *size = (caddr_t)aceptr - (caddr_t)z_acl;

        return (0);
}

/*
 * Copy ZFS ACEs to fixed size ace_t layout
 */
static void
zfs_copy_fuid_2_ace(zfsvfs_t *zfsvfs, zfs_acl_t *aclp, cred_t *cr,
    void *datap, int filter)
{
        uint64_t who;
        uint32_t access_mask;
        uint16_t iflags, type;
        zfs_ace_hdr_t *zacep = NULL;
        ace_t *acep = datap;
        ace_object_t *objacep;
        zfs_object_ace_t *zobjacep;
        size_t ace_size;
        uint16_t entry_type;
        zfs_acl_iter_t  zai = {0};

        zai.zai_aclp = aclp;
        while (zacep = zfs_acl_next_ace(&zai, zacep,
            &who, &access_mask, &iflags, &type)) {

                switch (type) {
                case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
                case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
                case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
                case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                        if (filter) {
                                continue;
                        }
                        zobjacep = (zfs_object_ace_t *)zacep;
                        objacep = (ace_object_t *)acep;
                        bcopy(zobjacep->z_object_type,
                            objacep->a_obj_type,
                            sizeof (zobjacep->z_object_type));
                        bcopy(zobjacep->z_inherit_type,
                            objacep->a_inherit_obj_type,
                            sizeof (zobjacep->z_inherit_type));
                        ace_size = sizeof (ace_object_t);
                        break;
                default:
                        ace_size = sizeof (ace_t);
                        break;
                }

                entry_type = (iflags & ACE_TYPE_FLAGS);
                if ((entry_type != ACE_OWNER &&
                    entry_type != OWNING_GROUP &&
                    entry_type != ACE_EVERYONE)) {
                        acep->a_who = zfs_fuid_map_id(zfsvfs, who,
                            cr, (entry_type & ACE_IDENTIFIER_GROUP) ?
                            ZFS_ACE_GROUP : ZFS_ACE_USER);
                } else {
                        acep->a_who = (uid_t)(int64_t)who;
                }
                acep->a_access_mask = access_mask;
                acep->a_flags = iflags;
                acep->a_type = type;
                acep = (ace_t *)((caddr_t)acep + ace_size);
        }
}

static int
zfs_copy_ace_2_oldace(vtype_t obj_type, zfs_acl_t *aclp, ace_t *acep,
    zfs_oldace_t *z_acl, int aclcnt, size_t *size)
{
        int i;
        zfs_oldace_t *aceptr = z_acl;

        for (i = 0; i != aclcnt; i++, aceptr++) {
                aceptr->z_access_mask = acep[i].a_access_mask;
                aceptr->z_type = acep[i].a_type;
                aceptr->z_flags = acep[i].a_flags;
                aceptr->z_fuid = acep[i].a_who;
                /*
                 * Make sure ACE is valid
                 */
                if (zfs_ace_valid(obj_type, aclp, aceptr->z_type,
                    aceptr->z_flags) != B_TRUE)
                        return (SET_ERROR(EINVAL));
        }
        *size = (caddr_t)aceptr - (caddr_t)z_acl;
        return (0);
}

/*
 * convert old ACL format to new
 */
void
zfs_acl_xform(znode_t *zp, zfs_acl_t *aclp, cred_t *cr)
{
        zfs_oldace_t *oldaclp;
        int i;
        uint16_t type, iflags;
        uint32_t access_mask;
        uint64_t who;
        void *cookie = NULL;
        zfs_acl_node_t *newaclnode;
        zfs_acl_iter_t  zai = {0};

        ASSERT(aclp->z_version == ZFS_ACL_VERSION_INITIAL);
        /*
         * First create the ACE in a contiguous piece of memory
         * for zfs_copy_ace_2_fuid().
         *
         * We only convert an ACL once, so this won't happen
         * everytime.
         */
        oldaclp = kmem_alloc(sizeof (zfs_oldace_t) * aclp->z_acl_count,
            KM_SLEEP);
        i = 0;

        zai.zai_aclp = aclp;
        while (cookie = zfs_acl_next_ace(&zai, cookie, &who,
            &access_mask, &iflags, &type)) {
                oldaclp[i].z_flags = iflags;
                oldaclp[i].z_type = type;
                oldaclp[i].z_fuid = who;
                oldaclp[i++].z_access_mask = access_mask;
        }

        newaclnode = zfs_acl_node_alloc(aclp->z_acl_count *
            sizeof (zfs_object_ace_t));
        aclp->z_ops = zfs_acl_fuid_ops;
        VERIFY(zfs_copy_ace_2_fuid(zp->z_zfsvfs, ZTOV(zp)->v_type, aclp,
            oldaclp, newaclnode->z_acldata, aclp->z_acl_count,
            &newaclnode->z_size, NULL, cr) == 0);
        newaclnode->z_ace_count = aclp->z_acl_count;
        aclp->z_version = ZFS_ACL_VERSION;
        kmem_free(oldaclp, aclp->z_acl_count * sizeof (zfs_oldace_t));

        /*
         * Release all previous ACL nodes
         */

        zfs_acl_release_nodes(aclp);

        list_insert_head(&aclp->z_acl, newaclnode);

        aclp->z_acl_bytes = newaclnode->z_size;
        aclp->z_acl_count = newaclnode->z_ace_count;

}

/*
 * Convert unix access mask to v4 access mask
 */
static uint32_t
zfs_unix_to_v4(uint32_t access_mask)
{
        uint32_t new_mask = 0;

        if (access_mask & S_IXOTH)
                new_mask |= ACE_EXECUTE;
        if (access_mask & S_IWOTH)
                new_mask |= ACE_WRITE_DATA;
        if (access_mask & S_IROTH)
                new_mask |= ACE_READ_DATA;
        return (new_mask);
}

static void
zfs_set_ace(zfs_acl_t *aclp, void *acep, uint32_t access_mask,
    uint16_t access_type, uint64_t fuid, uint16_t entry_type)
{
        uint16_t type = entry_type & ACE_TYPE_FLAGS;

        aclp->z_ops.ace_mask_set(acep, access_mask);
        aclp->z_ops.ace_type_set(acep, access_type);
        aclp->z_ops.ace_flags_set(acep, entry_type);
        if ((type != ACE_OWNER && type != OWNING_GROUP &&
            type != ACE_EVERYONE))
                aclp->z_ops.ace_who_set(acep, fuid);
}

/*
 * Determine mode of file based on ACL.
 */
uint64_t
zfs_mode_compute(uint64_t fmode, zfs_acl_t *aclp,
    uint64_t *pflags, uint64_t fuid, uint64_t fgid)
{
        int             entry_type;
        mode_t          mode;
        mode_t          seen = 0;
        zfs_ace_hdr_t   *acep = NULL;
        uint64_t        who;
        uint16_t        iflags, type;
        uint32_t        access_mask;
        boolean_t       an_exec_denied = B_FALSE;
        zfs_acl_iter_t  zai = {0};

        mode = (fmode & (S_IFMT | S_ISUID | S_ISGID | S_ISVTX));

        zai.zai_aclp = aclp;
        while (acep = zfs_acl_next_ace(&zai, acep, &who,
            &access_mask, &iflags, &type)) {

                if (!zfs_acl_valid_ace_type(type, iflags))
                        continue;

                entry_type = (iflags & ACE_TYPE_FLAGS);

                /*
                 * Skip over any inherit_only ACEs
                 */
                if (iflags & ACE_INHERIT_ONLY_ACE)
                        continue;

                if (entry_type == ACE_OWNER || (entry_type == 0 &&
                    who == fuid)) {
                        if ((access_mask & ACE_READ_DATA) &&
                            (!(seen & S_IRUSR))) {
                                seen |= S_IRUSR;
                                if (type == ALLOW) {
                                        mode |= S_IRUSR;
                                }
                        }
                        if ((access_mask & ACE_WRITE_DATA) &&
                            (!(seen & S_IWUSR))) {
                                seen |= S_IWUSR;
                                if (type == ALLOW) {
                                        mode |= S_IWUSR;
                                }
                        }
                        if ((access_mask & ACE_EXECUTE) &&
                            (!(seen & S_IXUSR))) {
                                seen |= S_IXUSR;
                                if (type == ALLOW) {
                                        mode |= S_IXUSR;
                                }
                        }
                } else if (entry_type == OWNING_GROUP ||
                    (entry_type == ACE_IDENTIFIER_GROUP && who == fgid)) {
                        if ((access_mask & ACE_READ_DATA) &&
                            (!(seen & S_IRGRP))) {
                                seen |= S_IRGRP;
                                if (type == ALLOW) {
                                        mode |= S_IRGRP;
                                }
                        }
                        if ((access_mask & ACE_WRITE_DATA) &&
                            (!(seen & S_IWGRP))) {
                                seen |= S_IWGRP;
                                if (type == ALLOW) {
                                        mode |= S_IWGRP;
                                }
                        }
                        if ((access_mask & ACE_EXECUTE) &&
                            (!(seen & S_IXGRP))) {
                                seen |= S_IXGRP;
                                if (type == ALLOW) {
                                        mode |= S_IXGRP;
                                }
                        }
                } else if (entry_type == ACE_EVERYONE) {
                        if ((access_mask & ACE_READ_DATA)) {
                                if (!(seen & S_IRUSR)) {
                                        seen |= S_IRUSR;
                                        if (type == ALLOW) {
                                                mode |= S_IRUSR;
                                        }
                                }
                                if (!(seen & S_IRGRP)) {
                                        seen |= S_IRGRP;
                                        if (type == ALLOW) {
                                                mode |= S_IRGRP;
                                        }
                                }
                                if (!(seen & S_IROTH)) {
                                        seen |= S_IROTH;
                                        if (type == ALLOW) {
                                                mode |= S_IROTH;
                                        }
                                }
                        }
                        if ((access_mask & ACE_WRITE_DATA)) {
                                if (!(seen & S_IWUSR)) {
                                        seen |= S_IWUSR;
                                        if (type == ALLOW) {
                                                mode |= S_IWUSR;
                                        }
                                }
                                if (!(seen & S_IWGRP)) {
                                        seen |= S_IWGRP;
                                        if (type == ALLOW) {
                                                mode |= S_IWGRP;
                                        }
                                }
                                if (!(seen & S_IWOTH)) {
                                        seen |= S_IWOTH;
                                        if (type == ALLOW) {
                                                mode |= S_IWOTH;
                                        }
                                }
                        }
                        if ((access_mask & ACE_EXECUTE)) {
                                if (!(seen & S_IXUSR)) {
                                        seen |= S_IXUSR;
                                        if (type == ALLOW) {
                                                mode |= S_IXUSR;
                                        }
                                }
                                if (!(seen & S_IXGRP)) {
                                        seen |= S_IXGRP;
                                        if (type == ALLOW) {
                                                mode |= S_IXGRP;
                                        }
                                }
                                if (!(seen & S_IXOTH)) {
                                        seen |= S_IXOTH;
                                        if (type == ALLOW) {
                                                mode |= S_IXOTH;
                                        }
                                }
                        }
                } else {
                        /*
                         * Only care if this IDENTIFIER_GROUP or
                         * USER ACE denies execute access to someone,
                         * mode is not affected
                         */
                        if ((access_mask & ACE_EXECUTE) && type == DENY)
                                an_exec_denied = B_TRUE;
                }
        }

        /*
         * Failure to allow is effectively a deny, so execute permission
         * is denied if it was never mentioned or if we explicitly
         * weren't allowed it.
         */
        if (!an_exec_denied &&
            ((seen & ALL_MODE_EXECS) != ALL_MODE_EXECS ||
            (mode & ALL_MODE_EXECS) != ALL_MODE_EXECS))
                an_exec_denied = B_TRUE;

        if (an_exec_denied)
                *pflags &= ~ZFS_NO_EXECS_DENIED;
        else
                *pflags |= ZFS_NO_EXECS_DENIED;

        return (mode);
}

/*
 * Read an external acl object.  If the intent is to modify, always
 * create a new acl and leave any cached acl in place.
 */
int
zfs_acl_node_read(struct znode *zp, boolean_t have_lock, zfs_acl_t **aclpp,
    boolean_t will_modify)
{
        zfs_acl_t       *aclp;
        int             aclsize;
        int             acl_count;
        zfs_acl_node_t  *aclnode;
        zfs_acl_phys_t  znode_acl;
        int             version;
        int             error;
        boolean_t       drop_lock = B_FALSE;

        ASSERT(RW_ISWRITER(&zp->z_acl_lock));

        if (zp->z_acl_cached && !will_modify) {
                *aclpp = zp->z_acl_cached;
                return (0);
        }

        /*
         * close race where znode could be upgrade while trying to
         * read the znode attributes.
         *
         * But this could only happen if the file isn't already an SA
         * znode
         */
        if (!zp->z_is_sa && !have_lock) {
                mutex_enter(&zp->z_lock);
                drop_lock = B_TRUE;
        }
        version = zfs_znode_acl_version(zp);

        if ((error = zfs_acl_znode_info(zp, &aclsize,
            &acl_count, &znode_acl)) != 0) {
                goto done;
        }

        aclp = zfs_acl_alloc(version);

        aclp->z_acl_count = acl_count;
        aclp->z_acl_bytes = aclsize;

        aclnode = zfs_acl_node_alloc(aclsize);
        aclnode->z_ace_count = aclp->z_acl_count;
        aclnode->z_size = aclsize;

        if (!zp->z_is_sa) {
                if (znode_acl.z_acl_extern_obj) {
                        error = dmu_read(zp->z_zfsvfs->z_os,
                            znode_acl.z_acl_extern_obj, 0, aclnode->z_size,
                            aclnode->z_acldata, DMU_READ_PREFETCH);
                } else {
                        bcopy(znode_acl.z_ace_data, aclnode->z_acldata,
                            aclnode->z_size);
                }
        } else {
                error = sa_lookup(zp->z_sa_hdl, SA_ZPL_DACL_ACES(zp->z_zfsvfs),
                    aclnode->z_acldata, aclnode->z_size);
        }

        if (error != 0) {
                zfs_acl_free(aclp);
                zfs_acl_node_free(aclnode);
                /* convert checksum errors into IO errors */
                if (error == ECKSUM)
                        error = SET_ERROR(EIO);
                goto done;
        }

        list_insert_head(&aclp->z_acl, aclnode);

        *aclpp = aclp;
        if (!will_modify)
                zp->z_acl_cached = aclp;
done:
        if (drop_lock)
                mutex_exit(&zp->z_lock);
        return (error);
}

/*ARGSUSED*/
void
zfs_acl_data_locator(void **dataptr, uint32_t *length, uint32_t buflen,
    boolean_t start, void *userdata)
{
        zfs_acl_locator_cb_t *cb = (zfs_acl_locator_cb_t *)userdata;

        if (start) {
                cb->cb_acl_node = list_head(&cb->cb_aclp->z_acl);
        } else {
                cb->cb_acl_node = list_next(&cb->cb_aclp->z_acl,
                    cb->cb_acl_node);
        }
        *dataptr = cb->cb_acl_node->z_acldata;
        *length = cb->cb_acl_node->z_size;
}

int
zfs_acl_chown_setattr(znode_t *zp)
{
        int error;
        zfs_acl_t *aclp;

        ASSERT(MUTEX_HELD(&zp->z_lock));
        ASSERT(RW_ISWRITER(&zp->z_acl_lock));

        if ((error = zfs_acl_node_read(zp, B_TRUE, &aclp, B_FALSE)) == 0)
                zp->z_mode = zfs_mode_compute(zp->z_mode, aclp,
                    &zp->z_pflags, zp->z_uid, zp->z_gid);
        return (error);
}

/*
 * common code for setting ACLs.
 *
 * This function is called from zfs_mode_update, zfs_perm_init, and zfs_setacl.
 * zfs_setacl passes a non-NULL inherit pointer (ihp) to indicate that it's
 * already checked the acl and knows whether to inherit.
 */
int
zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr, dmu_tx_t *tx)
{
        int                     error;
        zfsvfs_t                *zfsvfs = zp->z_zfsvfs;
        dmu_object_type_t       otype;
        zfs_acl_locator_cb_t    locate = { 0 };
        uint64_t                mode;
        sa_bulk_attr_t          bulk[5];
        uint64_t                ctime[2];
        int                     count = 0;
        zfs_acl_phys_t          acl_phys;
        zfs_acl_iter_t          zai = {0};

        /*
         * One might be tempted to add here:
         * ASSERT(RW_ISWRITER(&zp->z_acl_lock));
         * and most callers have that lock, but zfs_mknode
         * calls without the lock when making a new node,
         * which is OK because it's not visible yet.
         */

        mode = zp->z_mode;

        mode = zfs_mode_compute(mode, aclp, &zp->z_pflags,
            zp->z_uid, zp->z_gid);

        zp->z_mode = mode;
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MODE(zfsvfs), NULL,
            &mode, sizeof (mode));
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
            &zp->z_pflags, sizeof (zp->z_pflags));
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
            &ctime, sizeof (ctime));

        if (zp->z_acl_cached) {
                zfs_acl_free(zp->z_acl_cached);
                zp->z_acl_cached = NULL;
        }

        /*
         * Upgrade needed?
         */
        if (!zfsvfs->z_use_fuids) {
                otype = DMU_OT_OLDACL;
        } else {
                if ((aclp->z_version == ZFS_ACL_VERSION_INITIAL) &&
                    (zfsvfs->z_version >= ZPL_VERSION_FUID))
                        zfs_acl_xform(zp, aclp, cr);
                ASSERT(aclp->z_version >= ZFS_ACL_VERSION_FUID);
                otype = DMU_OT_ACL;
        }

        /*
         * Arrgh, we have to handle old on disk format
         * as well as newer (preferred) SA format.
         */

        if (zp->z_is_sa) { /* the easy case, just update the ACL attribute */
                locate.cb_aclp = aclp;
                SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_DACL_ACES(zfsvfs),
                    zfs_acl_data_locator, &locate, aclp->z_acl_bytes);
                SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_DACL_COUNT(zfsvfs),
                    NULL, &aclp->z_acl_count, sizeof (uint64_t));
        } else { /* Painful legacy way */
                zfs_acl_node_t *aclnode;
                uint64_t off = 0;
                uint64_t aoid;

                if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_ZNODE_ACL(zfsvfs),
                    &acl_phys, sizeof (acl_phys))) != 0)
                        return (error);

                aoid = acl_phys.z_acl_extern_obj;

                if (aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                        /*
                         * If ACL was previously external and we are now
                         * converting to new ACL format then release old
                         * ACL object and create a new one.
                         */
                        if (aoid &&
                            aclp->z_version != acl_phys.z_acl_version) {
                                error = dmu_object_free(zfsvfs->z_os, aoid, tx);
                                if (error)
                                        return (error);
                                aoid = 0;
                        }
                        if (aoid == 0) {
                                aoid = dmu_object_alloc(zfsvfs->z_os,
                                    otype, aclp->z_acl_bytes,
                                    otype == DMU_OT_ACL ?
                                    DMU_OT_SYSACL : DMU_OT_NONE,
                                    otype == DMU_OT_ACL ?
                                    DN_OLD_MAX_BONUSLEN : 0, tx);
                        } else {
                                (void) dmu_object_set_blocksize(zfsvfs->z_os,
                                    aoid, aclp->z_acl_bytes, 0, tx);
                        }
                        acl_phys.z_acl_extern_obj = aoid;
                        for (aclnode = list_head(&aclp->z_acl); aclnode;
                            aclnode = list_next(&aclp->z_acl, aclnode)) {
                                if (aclnode->z_ace_count == 0)
                                        continue;
                                dmu_write(zfsvfs->z_os, aoid, off,
                                    aclnode->z_size, aclnode->z_acldata, tx);
                                off += aclnode->z_size;
                        }
                } else {
                        void *start = acl_phys.z_ace_data;
                        /*
                         * Migrating back embedded?
                         */
                        if (acl_phys.z_acl_extern_obj) {
                                error = dmu_object_free(zfsvfs->z_os,
                                    acl_phys.z_acl_extern_obj, tx);
                                if (error)
                                        return (error);
                                acl_phys.z_acl_extern_obj = 0;
                        }

                        for (aclnode = list_head(&aclp->z_acl); aclnode;
                            aclnode = list_next(&aclp->z_acl, aclnode)) {
                                if (aclnode->z_ace_count == 0)
                                        continue;
                                bcopy(aclnode->z_acldata, start,
                                    aclnode->z_size);
                                start = (caddr_t)start + aclnode->z_size;
                        }
                }
                /*
                 * If Old version then swap count/bytes to match old
                 * layout of znode_acl_phys_t.
                 */
                if (aclp->z_version == ZFS_ACL_VERSION_INITIAL) {
                        acl_phys.z_acl_size = aclp->z_acl_count;
                        acl_phys.z_acl_count = aclp->z_acl_bytes;
                } else {
                        acl_phys.z_acl_size = aclp->z_acl_bytes;
                        acl_phys.z_acl_count = aclp->z_acl_count;
                }
                acl_phys.z_acl_version = aclp->z_version;

                SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_ZNODE_ACL(zfsvfs), NULL,
                    &acl_phys, sizeof (acl_phys));
        }

        /*
         * Replace ACL wide bits, but first clear them.
         */
        zp->z_pflags &= ~ZFS_ACL_WIDE_FLAGS;

        zp->z_pflags |= aclp->z_hints;

        zai.zai_aclp = aclp;
        if (ace_trivial_common(&zai, 0, zfs_ace_walk) == 0)
                zp->z_pflags |= ZFS_ACL_TRIVIAL;

        zfs_tstamp_update_setup(zp, STATE_CHANGED, NULL, ctime, B_TRUE);
        return (sa_bulk_update(zp->z_sa_hdl, bulk, count, tx));
}

static void
zfs_acl_chmod(vtype_t vtype, uint64_t mode, boolean_t split, boolean_t trim,
    zfs_acl_t *aclp)
{
        void            *acep = NULL;
        uint64_t        who;
        int             new_count, new_bytes;
        int             ace_size;
        int             entry_type;
        uint16_t        iflags, type;
        uint32_t        access_mask;
        zfs_acl_node_t  *newnode;
        size_t          abstract_size = aclp->z_ops.ace_abstract_size();
        void            *zacep;
        boolean_t       isdir;
        trivial_acl_t   masks;
        zfs_acl_iter_t  zai = {0};

        new_count = new_bytes = 0;

        isdir = (vtype == VDIR);

        acl_trivial_access_masks((mode_t)mode, isdir, &masks);

        newnode = zfs_acl_node_alloc((abstract_size * 6) + aclp->z_acl_bytes);

        zacep = newnode->z_acldata;
        if (masks.allow0) {
                zfs_set_ace(aclp, zacep, masks.allow0, ALLOW, -1, ACE_OWNER);
                zacep = (void *)((uintptr_t)zacep + abstract_size);
                new_count++;
                new_bytes += abstract_size;
        }
        if (masks.deny1) {
                zfs_set_ace(aclp, zacep, masks.deny1, DENY, -1, ACE_OWNER);
                zacep = (void *)((uintptr_t)zacep + abstract_size);
                new_count++;
                new_bytes += abstract_size;
        }
        if (masks.deny2) {
                zfs_set_ace(aclp, zacep, masks.deny2, DENY, -1, OWNING_GROUP);
                zacep = (void *)((uintptr_t)zacep + abstract_size);
                new_count++;
                new_bytes += abstract_size;
        }

        zai.zai_aclp = aclp;
        while (acep = zfs_acl_next_ace(&zai, acep, &who, &access_mask,
            &iflags, &type)) {
                entry_type = (iflags & ACE_TYPE_FLAGS);
                /*
                 * ACEs used to represent the file mode may be divided
                 * into an equivalent pair of inherit-only and regular
                 * ACEs, if they are inheritable.
                 * Skip regular ACEs, which are replaced by the new mode.
                 */
                if (split && (entry_type == ACE_OWNER ||
                    entry_type == OWNING_GROUP ||
                    entry_type == ACE_EVERYONE)) {
                        if (!isdir || !(iflags &
                            (ACE_FILE_INHERIT_ACE|ACE_DIRECTORY_INHERIT_ACE)))
                                continue;
                        /*
                         * We preserve owner@, group@, or @everyone
                         * permissions, if they are inheritable, by
                         * copying them to inherit_only ACEs. This
                         * prevents inheritable permissions from being
                         * altered along with the file mode.
                         */
                        iflags |= ACE_INHERIT_ONLY_ACE;
                }

                /*
                 * If this ACL has any inheritable ACEs, mark that in
                 * the hints (which are later masked into the pflags)
                 * so create knows to do inheritance.
                 */
                if (isdir && (iflags &
                    (ACE_FILE_INHERIT_ACE|ACE_DIRECTORY_INHERIT_ACE)))
                        aclp->z_hints |= ZFS_INHERIT_ACE;

                if ((type != ALLOW && type != DENY) ||
                    (iflags & ACE_INHERIT_ONLY_ACE)) {
                        switch (type) {
                        case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
                        case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
                        case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
                        case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                                aclp->z_hints |= ZFS_ACL_OBJ_ACE;
                                break;
                        }
                } else {
                        /*
                         * Limit permissions granted by ACEs to be no greater
                         * than permissions of the requested group mode.
                         * Applies when the "aclmode" property is set to
                         * "groupmask".
                         */
                        if ((type == ALLOW) && trim)
                                access_mask &= masks.group;
                }
                zfs_set_ace(aclp, zacep, access_mask, type, who, iflags);
                ace_size = aclp->z_ops.ace_size(acep);
                zacep = (void *)((uintptr_t)zacep + ace_size);
                new_count++;
                new_bytes += ace_size;
        }
        zfs_set_ace(aclp, zacep, masks.owner, ALLOW, -1, ACE_OWNER);
        zacep = (void *)((uintptr_t)zacep + abstract_size);
        zfs_set_ace(aclp, zacep, masks.group, ALLOW, -1, OWNING_GROUP);
        zacep = (void *)((uintptr_t)zacep + abstract_size);
        zfs_set_ace(aclp, zacep, masks.everyone, ALLOW, -1, ACE_EVERYONE);

        new_count += 3;
        new_bytes += abstract_size * 3;
        zfs_acl_release_nodes(aclp);
        aclp->z_acl_count = new_count;
        aclp->z_acl_bytes = new_bytes;
        newnode->z_ace_count = new_count;
        newnode->z_size = new_bytes;
        list_insert_tail(&aclp->z_acl, newnode);
}

int
zfs_acl_chmod_setattr(znode_t *zp, zfs_acl_t **aclp, uint64_t mode)
{
        int error = 0;

        rw_enter(&zp->z_acl_lock, RW_WRITER);
        mutex_enter(&zp->z_lock);
        if (zp->z_zfsvfs->z_acl_mode == ZFS_ACL_DISCARD)
                *aclp = zfs_acl_alloc(zfs_acl_version_zp(zp));
        else
                error = zfs_acl_node_read(zp, B_TRUE, aclp, B_TRUE);

        if (error == 0) {
                (*aclp)->z_hints = zp->z_pflags & V4_ACL_WIDE_FLAGS;
                zfs_acl_chmod(ZTOV(zp)->v_type, mode, B_TRUE,
                    (zp->z_zfsvfs->z_acl_mode == ZFS_ACL_GROUPMASK), *aclp);
        }
        mutex_exit(&zp->z_lock);
        rw_exit(&zp->z_acl_lock);

        return (error);
}

/*
 * Should ACE be inherited?
 */
static int
zfs_ace_can_use(vtype_t vtype, uint16_t acep_flags)
{
        int     iflags = (acep_flags & 0xf);

        if ((vtype == VDIR) && (iflags & ACE_DIRECTORY_INHERIT_ACE))
                return (1);
        else if (iflags & ACE_FILE_INHERIT_ACE)
                return (!((vtype == VDIR) &&
                    (iflags & ACE_NO_PROPAGATE_INHERIT_ACE)));
        return (0);
}

/*
 * inherit inheritable ACEs from parent
 */
static zfs_acl_t *
zfs_acl_inherit(zfsvfs_t *zfsvfs, vtype_t vtype, zfs_acl_t *paclp,
    uint64_t mode, boolean_t *need_chmod)
{
        void            *pacep = NULL;
        void            *acep;
        zfs_acl_node_t  *aclnode;
        zfs_acl_t       *aclp = NULL;
        uint64_t        who;
        uint32_t        access_mask;
        uint16_t        iflags, newflags, type;
        size_t          ace_size;
        void            *data1, *data2;
        size_t          data1sz, data2sz;
        uint_t          aclinherit;
        boolean_t       isdir = (vtype == VDIR);
        boolean_t       isreg = (vtype == VREG);
        zfs_acl_iter_t  zai = {0};

        *need_chmod = B_TRUE;

        aclp = zfs_acl_alloc(paclp->z_version);
        aclinherit = zfsvfs->z_acl_inherit;
        if (aclinherit == ZFS_ACL_DISCARD || vtype == VLNK)
                return (aclp);

        zai.zai_aclp = paclp;
        while (pacep = zfs_acl_next_ace(&zai, pacep, &who,
            &access_mask, &iflags, &type)) {

                /*
                 * don't inherit bogus ACEs
                 */
                if (!zfs_acl_valid_ace_type(type, iflags))
                        continue;

                /*
                 * Check if ACE is inheritable by this vnode
                 */
                if ((aclinherit == ZFS_ACL_NOALLOW && type == ALLOW) ||
                    !zfs_ace_can_use(vtype, iflags))
                        continue;

                /*
                 * If owner@, group@, or everyone@ inheritable
                 * then zfs_acl_chmod() isn't needed.
                 */
                if ((aclinherit == ZFS_ACL_PASSTHROUGH ||
                    aclinherit == ZFS_ACL_PASSTHROUGH_X) &&
                    ((iflags & (ACE_OWNER|ACE_EVERYONE)) ||
                    ((iflags & OWNING_GROUP) == OWNING_GROUP)) &&
                    (isreg || (isdir && (iflags & ACE_DIRECTORY_INHERIT_ACE))))
                        *need_chmod = B_FALSE;

                /*
                 * Strip inherited execute permission from file if
                 * not in mode
                 */
                if (aclinherit == ZFS_ACL_PASSTHROUGH_X && type == ALLOW &&
                    !isdir && ((mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)) {
                        access_mask &= ~ACE_EXECUTE;
                }

                /*
                 * Strip write_acl and write_owner from permissions
                 * when inheriting an ACE
                 */
                if (aclinherit == ZFS_ACL_RESTRICTED && type == ALLOW) {
                        access_mask &= ~RESTRICTED_CLEAR;
                }

                ace_size = aclp->z_ops.ace_size(pacep);
                aclnode = zfs_acl_node_alloc(ace_size);
                list_insert_tail(&aclp->z_acl, aclnode);
                acep = aclnode->z_acldata;

                zfs_set_ace(aclp, acep, access_mask, type,
                    who, iflags|ACE_INHERITED_ACE);

                /*
                 * Copy special opaque data if any
                 */
                if ((data1sz = paclp->z_ops.ace_data(pacep, &data1)) != 0) {
                        VERIFY((data2sz = aclp->z_ops.ace_data(acep,
                            &data2)) == data1sz);
                        bcopy(data1, data2, data2sz);
                }

                aclp->z_acl_count++;
                aclnode->z_ace_count++;
                aclp->z_acl_bytes += aclnode->z_size;
                newflags = aclp->z_ops.ace_flags_get(acep);

                /*
                 * If ACE is not to be inherited further, or if the vnode is
                 * not a directory, remove all inheritance flags
                 */
                if (!isdir || (iflags & ACE_NO_PROPAGATE_INHERIT_ACE)) {
                        newflags &= ~ALL_INHERIT;
                        aclp->z_ops.ace_flags_set(acep,
                            newflags|ACE_INHERITED_ACE);
                        continue;
                }

                /*
                 * This directory has an inheritable ACE
                 */
                aclp->z_hints |= ZFS_INHERIT_ACE;

                /*
                 * If only FILE_INHERIT is set then turn on
                 * inherit_only
                 */
                if ((iflags & (ACE_FILE_INHERIT_ACE |
                    ACE_DIRECTORY_INHERIT_ACE)) == ACE_FILE_INHERIT_ACE) {
                        newflags |= ACE_INHERIT_ONLY_ACE;
                        aclp->z_ops.ace_flags_set(acep,
                            newflags|ACE_INHERITED_ACE);
                } else {
                        newflags &= ~ACE_INHERIT_ONLY_ACE;
                        aclp->z_ops.ace_flags_set(acep,
                            newflags|ACE_INHERITED_ACE);
                }
        }

        return (aclp);
}

/*
 * Create file system object initial permissions
 * including inheritable ACEs.
 * Also, create FUIDs for owner and group.
 */
int
zfs_acl_ids_create(znode_t *dzp, int flag, vattr_t *vap, cred_t *cr,
    vsecattr_t *vsecp, zfs_acl_ids_t *acl_ids)
{
        int             error;
        zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
        zfs_acl_t       *paclp;
        gid_t           gid;
        boolean_t       need_chmod = B_TRUE;
        boolean_t       trim = B_FALSE;
        boolean_t       inherited = B_FALSE;

        bzero(acl_ids, sizeof (zfs_acl_ids_t));
        acl_ids->z_mode = MAKEIMODE(vap->va_type, vap->va_mode);

        if (vsecp)
                if ((error = zfs_vsec_2_aclp(zfsvfs, vap->va_type, vsecp, cr,
                    &acl_ids->z_fuidp, &acl_ids->z_aclp)) != 0)
                        return (error);
        /*
         * Determine uid and gid.
         */
        if ((flag & IS_ROOT_NODE) || zfsvfs->z_replay ||
            ((flag & IS_XATTR) && (vap->va_type == VDIR))) {
                acl_ids->z_fuid = zfs_fuid_create(zfsvfs,
                    (uint64_t)vap->va_uid, cr,
                    ZFS_OWNER, &acl_ids->z_fuidp);
                acl_ids->z_fgid = zfs_fuid_create(zfsvfs,
                    (uint64_t)vap->va_gid, cr,
                    ZFS_GROUP, &acl_ids->z_fuidp);
                gid = vap->va_gid;
        } else {
                acl_ids->z_fuid = zfs_fuid_create_cred(zfsvfs, ZFS_OWNER,
                    cr, &acl_ids->z_fuidp);
                acl_ids->z_fgid = 0;
                if (vap->va_mask & AT_GID)  {
                        acl_ids->z_fgid = zfs_fuid_create(zfsvfs,
                            (uint64_t)vap->va_gid,
                            cr, ZFS_GROUP, &acl_ids->z_fuidp);
                        gid = vap->va_gid;
                        if (acl_ids->z_fgid != dzp->z_gid &&
                            !groupmember(vap->va_gid, cr) &&
                            secpolicy_vnode_create_gid(cr) != 0)
                                acl_ids->z_fgid = 0;
                }
                if (acl_ids->z_fgid == 0) {
                        if (dzp->z_mode & S_ISGID) {
                                char            *domain;
                                uint32_t        rid;

                                acl_ids->z_fgid = dzp->z_gid;
                                gid = zfs_fuid_map_id(zfsvfs, acl_ids->z_fgid,
                                    cr, ZFS_GROUP);

                                if (zfsvfs->z_use_fuids &&
                                    IS_EPHEMERAL(acl_ids->z_fgid)) {
                                        domain = zfs_fuid_idx_domain(
                                            &zfsvfs->z_fuid_idx,
                                            FUID_INDEX(acl_ids->z_fgid));
                                        rid = FUID_RID(acl_ids->z_fgid);
                                        zfs_fuid_node_add(&acl_ids->z_fuidp,
                                            domain, rid,
                                            FUID_INDEX(acl_ids->z_fgid),
                                            acl_ids->z_fgid, ZFS_GROUP);
                                }
                        } else {
                                acl_ids->z_fgid = zfs_fuid_create_cred(zfsvfs,
                                    ZFS_GROUP, cr, &acl_ids->z_fuidp);
                                gid = crgetgid(cr);
                        }
                }
        }

        /*
         * If we're creating a directory, and the parent directory has the
         * set-GID bit set, set in on the new directory.
         * Otherwise, if the user is neither privileged nor a member of the
         * file's new group, clear the file's set-GID bit.
         */

        if (!(flag & IS_ROOT_NODE) && (dzp->z_mode & S_ISGID) &&
            (vap->va_type == VDIR)) {
                acl_ids->z_mode |= S_ISGID;
        } else {
                if ((acl_ids->z_mode & S_ISGID) &&
                    secpolicy_vnode_setids_setgids(cr, gid) != 0)
                        acl_ids->z_mode &= ~S_ISGID;
        }

        if (acl_ids->z_aclp == NULL) {
                rw_enter(&dzp->z_acl_lock, RW_WRITER);
                mutex_enter(&dzp->z_lock);
                if (!(flag & IS_ROOT_NODE) &&
                    (dzp->z_pflags & ZFS_INHERIT_ACE) &&
                    !(dzp->z_pflags & ZFS_XATTR)) {
                        VERIFY(0 == zfs_acl_node_read(dzp, B_TRUE,
                            &paclp, B_FALSE));
                        acl_ids->z_aclp = zfs_acl_inherit(zfsvfs,
                            vap->va_type, paclp, acl_ids->z_mode, &need_chmod);
                        inherited = B_TRUE;
                } else {
                        acl_ids->z_aclp =
                            zfs_acl_alloc(zfs_acl_version_zp(dzp));
                        acl_ids->z_aclp->z_hints |= ZFS_ACL_TRIVIAL;
                }
                mutex_exit(&dzp->z_lock);
                rw_exit(&dzp->z_acl_lock);

                if (need_chmod) {
                        if (vap->va_type == VDIR)
                                acl_ids->z_aclp->z_hints |=
                                    ZFS_ACL_AUTO_INHERIT;

                        if (zfsvfs->z_acl_mode == ZFS_ACL_GROUPMASK &&
                            zfsvfs->z_acl_inherit != ZFS_ACL_PASSTHROUGH &&
                            zfsvfs->z_acl_inherit != ZFS_ACL_PASSTHROUGH_X)
                                trim = B_TRUE;
                        zfs_acl_chmod(vap->va_type, acl_ids->z_mode, B_FALSE,
                            trim, acl_ids->z_aclp);
                }
        }

        if (inherited || vsecp) {
                zfs_acl_iter_t  zai = {0};

                acl_ids->z_mode = zfs_mode_compute(acl_ids->z_mode,
                    acl_ids->z_aclp, &acl_ids->z_aclp->z_hints,
                    acl_ids->z_fuid, acl_ids->z_fgid);

                zai.zai_aclp = acl_ids->z_aclp;
                if (ace_trivial_common(&zai, 0, zfs_ace_walk) == 0)
                        acl_ids->z_aclp->z_hints |= ZFS_ACL_TRIVIAL;
        }

        return (0);
}

/*
 * Free ACL and fuid_infop, but not the acl_ids structure
 */
void
zfs_acl_ids_free(zfs_acl_ids_t *acl_ids)
{
        if (acl_ids->z_aclp)
                zfs_acl_free(acl_ids->z_aclp);
        if (acl_ids->z_fuidp)
                zfs_fuid_info_free(acl_ids->z_fuidp);
        acl_ids->z_aclp = NULL;
        acl_ids->z_fuidp = NULL;
}

boolean_t
zfs_acl_ids_overquota(zfsvfs_t *zv, zfs_acl_ids_t *acl_ids, uint64_t projid)
{
        return (zfs_id_overquota(zv, DMU_USERUSED_OBJECT, acl_ids->z_fuid) ||
            zfs_id_overquota(zv, DMU_GROUPUSED_OBJECT, acl_ids->z_fgid) ||
            (projid != ZFS_DEFAULT_PROJID && projid != ZFS_INVALID_PROJID &&
            zfs_id_overquota(zv, DMU_PROJECTUSED_OBJECT, projid)));
}

/*
 * Retrieve a file's ACL
 */
int
zfs_getacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
{
        zfs_acl_t       *aclp;
        ulong_t         mask;
        int             error;
        int             count = 0;
        int             largeace = 0;

        mask = vsecp->vsa_mask & (VSA_ACE | VSA_ACECNT |
            VSA_ACE_ACLFLAGS | VSA_ACE_ALLTYPES);

        if (mask == 0)
                return (SET_ERROR(ENOSYS));

        if (error = zfs_zaccess(zp, ACE_READ_ACL, 0, skipaclchk, cr))
                return (error);

        /*
         * This may be frequently called, so when possible
         * try to avoid entering z_acl_lock as writer.
         */
        rw_enter(&zp->z_acl_lock, RW_READER);
        aclp = zp->z_acl_cached;
        if (aclp == NULL) {
                /*
                 * OK, need WRITER to load the ACL.  Note:
                 * zfs_acl_node_read() re-checks zp->z_acl_cached
                 * and just returns if it's set.
                 */
                rw_exit(&zp->z_acl_lock);
                rw_enter(&zp->z_acl_lock, RW_WRITER);

                error = zfs_acl_node_read(zp, B_FALSE, &aclp, B_FALSE);
                if (error != 0) {
                        rw_exit(&zp->z_acl_lock);
                        return (error);
                }
                rw_downgrade(&zp->z_acl_lock);  /* now RW_READER */
                ASSERT(zp->z_acl_cached);
        }

        /*
         * Scan ACL to determine number of ACEs
         */
        if ((zp->z_pflags & ZFS_ACL_OBJ_ACE) && !(mask & VSA_ACE_ALLTYPES)) {
                void *zacep = NULL;
                uint64_t who;
                uint32_t access_mask;
                uint16_t type, iflags;
                zfs_acl_iter_t  zai = {0};

                zai.zai_aclp = aclp;
                while (zacep = zfs_acl_next_ace(&zai, zacep,
                    &who, &access_mask, &iflags, &type)) {
                        switch (type) {
                        case ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE:
                        case ACE_ACCESS_DENIED_OBJECT_ACE_TYPE:
                        case ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE:
                        case ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE:
                                largeace++;
                                continue;
                        default:
                                count++;
                        }
                }
                vsecp->vsa_aclcnt = count;
        } else
                count = (int)aclp->z_acl_count;

        if (mask & VSA_ACECNT) {
                vsecp->vsa_aclcnt = count;
        }

        if (mask & VSA_ACE) {
                size_t aclsz;

                aclsz = count * sizeof (ace_t) +
                    sizeof (ace_object_t) * largeace;

                vsecp->vsa_aclentp = kmem_alloc(aclsz, KM_SLEEP);
                vsecp->vsa_aclentsz = aclsz;

                if (aclp->z_version == ZFS_ACL_VERSION_FUID)
                        zfs_copy_fuid_2_ace(zp->z_zfsvfs, aclp, cr,
                            vsecp->vsa_aclentp, !(mask & VSA_ACE_ALLTYPES));
                else {
                        zfs_acl_node_t *aclnode;
                        void *start = vsecp->vsa_aclentp;

                        for (aclnode = list_head(&aclp->z_acl); aclnode;
                            aclnode = list_next(&aclp->z_acl, aclnode)) {
                                bcopy(aclnode->z_acldata, start,
                                    aclnode->z_size);
                                start = (caddr_t)start + aclnode->z_size;
                        }
                        ASSERT((caddr_t)start - (caddr_t)vsecp->vsa_aclentp ==
                            aclp->z_acl_bytes);
                }
        }
        if (mask & VSA_ACE_ACLFLAGS) {
                vsecp->vsa_aclflags = 0;
                if (zp->z_pflags & ZFS_ACL_DEFAULTED)
                        vsecp->vsa_aclflags |= ACL_DEFAULTED;
                if (zp->z_pflags & ZFS_ACL_PROTECTED)
                        vsecp->vsa_aclflags |= ACL_PROTECTED;
                if (zp->z_pflags & ZFS_ACL_AUTO_INHERIT)
                        vsecp->vsa_aclflags |= ACL_AUTO_INHERIT;
        }

        rw_exit(&zp->z_acl_lock);

        return (0);
}

int
zfs_vsec_2_aclp(zfsvfs_t *zfsvfs, vtype_t obj_type,
    vsecattr_t *vsecp, cred_t *cr, zfs_fuid_info_t **fuidp, zfs_acl_t **zaclp)
{
        zfs_acl_t *aclp;
        zfs_acl_node_t *aclnode;
        int aclcnt = vsecp->vsa_aclcnt;
        int error;

        if (vsecp->vsa_aclcnt > MAX_ACL_ENTRIES || vsecp->vsa_aclcnt <= 0)
                return (SET_ERROR(EINVAL));

        aclp = zfs_acl_alloc(zfs_acl_version(zfsvfs->z_version));

        aclp->z_hints = 0;
        aclnode = zfs_acl_node_alloc(aclcnt * sizeof (zfs_object_ace_t));
        if (aclp->z_version == ZFS_ACL_VERSION_INITIAL) {
                if ((error = zfs_copy_ace_2_oldace(obj_type, aclp,
                    (ace_t *)vsecp->vsa_aclentp, aclnode->z_acldata,
                    aclcnt, &aclnode->z_size)) != 0) {
                        zfs_acl_free(aclp);
                        zfs_acl_node_free(aclnode);
                        return (error);
                }
        } else {
                if ((error = zfs_copy_ace_2_fuid(zfsvfs, obj_type, aclp,
                    vsecp->vsa_aclentp, aclnode->z_acldata, aclcnt,
                    &aclnode->z_size, fuidp, cr)) != 0) {
                        zfs_acl_free(aclp);
                        zfs_acl_node_free(aclnode);
                        return (error);
                }
        }
        aclp->z_acl_bytes = aclnode->z_size;
        aclnode->z_ace_count = aclcnt;
        aclp->z_acl_count = aclcnt;
        list_insert_head(&aclp->z_acl, aclnode);

        /*
         * If flags are being set then add them to z_hints
         */
        if (vsecp->vsa_mask & VSA_ACE_ACLFLAGS) {
                if (vsecp->vsa_aclflags & ACL_PROTECTED)
                        aclp->z_hints |= ZFS_ACL_PROTECTED;
                if (vsecp->vsa_aclflags & ACL_DEFAULTED)
                        aclp->z_hints |= ZFS_ACL_DEFAULTED;
                if (vsecp->vsa_aclflags & ACL_AUTO_INHERIT)
                        aclp->z_hints |= ZFS_ACL_AUTO_INHERIT;
        }

        *zaclp = aclp;

        return (0);
}

/*
 * Set a file's ACL
 */
int
zfs_setacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
{
        zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
        zilog_t         *zilog = zfsvfs->z_log;
        ulong_t         mask = vsecp->vsa_mask & (VSA_ACE | VSA_ACECNT);
        dmu_tx_t        *tx;
        int             error;
        zfs_acl_t       *aclp;
        zfs_fuid_info_t *fuidp = NULL;
        boolean_t       fuid_dirtied;
        uint64_t        acl_obj;

        if (mask == 0)
                return (SET_ERROR(ENOSYS));

        if (zp->z_pflags & ZFS_IMMUTABLE)
                return (SET_ERROR(EPERM));

        if (error = zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr))
                return (error);

        error = zfs_vsec_2_aclp(zfsvfs, ZTOV(zp)->v_type, vsecp, cr, &fuidp,
            &aclp);
        if (error)
                return (error);

        /*
         * If ACL wide flags aren't being set then preserve any
         * existing flags.
         */
        if (!(vsecp->vsa_mask & VSA_ACE_ACLFLAGS)) {
                aclp->z_hints |=
                    (zp->z_pflags & V4_ACL_WIDE_FLAGS);
        }
top:
        rw_enter(&zp->z_acl_lock, RW_WRITER);
        mutex_enter(&zp->z_lock);

        tx = dmu_tx_create(zfsvfs->z_os);

        dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);

        fuid_dirtied = zfsvfs->z_fuid_dirty;
        if (fuid_dirtied)
                zfs_fuid_txhold(zfsvfs, tx);

        /*
         * If old version and ACL won't fit in bonus and we aren't
         * upgrading then take out necessary DMU holds
         */

        if ((acl_obj = zfs_external_acl(zp)) != 0) {
                if (zfsvfs->z_version >= ZPL_VERSION_FUID &&
                    zfs_znode_acl_version(zp) <= ZFS_ACL_VERSION_INITIAL) {
                        dmu_tx_hold_free(tx, acl_obj, 0,
                            DMU_OBJECT_END);
                        dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
                            aclp->z_acl_bytes);
                } else {
                        dmu_tx_hold_write(tx, acl_obj, 0, aclp->z_acl_bytes);
                }
        } else if (!zp->z_is_sa && aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, aclp->z_acl_bytes);
        }

        zfs_sa_upgrade_txholds(tx, zp);
        error = dmu_tx_assign(tx, TXG_NOWAIT);
        if (error) {
                rw_exit(&zp->z_acl_lock);
                mutex_exit(&zp->z_lock);

                if (error == ERESTART) {
                        dmu_tx_wait(tx);
                        dmu_tx_abort(tx);
                        goto top;
                }
                dmu_tx_abort(tx);
                zfs_acl_free(aclp);
                return (error);
        }

        error = zfs_aclset_common(zp, aclp, cr, tx);
        ASSERT(error == 0);
        ASSERT(zp->z_acl_cached == NULL);
        zp->z_acl_cached = aclp;

        if (fuid_dirtied)
                zfs_fuid_sync(zfsvfs, tx);

        zfs_log_acl(zilog, tx, zp, vsecp, fuidp);

        if (fuidp)
                zfs_fuid_info_free(fuidp);
        dmu_tx_commit(tx);
        mutex_exit(&zp->z_lock);
        rw_exit(&zp->z_acl_lock);

        return (error);
}

/*
 * Check accesses of interest (AoI) against attributes of the dataset
 * such as read-only.  Returns zero if no AoI conflict with dataset
 * attributes, otherwise an appropriate errno is returned.
 */
static int
zfs_zaccess_dataset_check(znode_t *zp, uint32_t v4_mode)
{
        if ((v4_mode & WRITE_MASK) &&
            (zp->z_zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) &&
            (!IS_DEVVP(ZTOV(zp)) ||
            (IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS)))) {
                return (SET_ERROR(EROFS));
        }

        /*
         * Intentionally allow ZFS_READONLY through here.
         * See zfs_zaccess_common().
         */
        if ((v4_mode & WRITE_MASK_DATA) &&
            (zp->z_pflags & ZFS_IMMUTABLE)) {
                return (SET_ERROR(EPERM));
        }

        if ((v4_mode & (ACE_DELETE | ACE_DELETE_CHILD)) &&
            (zp->z_pflags & ZFS_NOUNLINK)) {
                return (SET_ERROR(EPERM));
        }

        if (((v4_mode & (ACE_READ_DATA|ACE_EXECUTE)) &&
            (zp->z_pflags & ZFS_AV_QUARANTINED))) {
                return (SET_ERROR(EACCES));
        }

        return (0);
}

/*
 * The primary usage of this function is to loop through all of the
 * ACEs in the znode, determining what accesses of interest (AoI) to
 * the caller are allowed or denied.  The AoI are expressed as bits in
 * the working_mode parameter.  As each ACE is processed, bits covered
 * by that ACE are removed from the working_mode.  This removal
 * facilitates two things.  The first is that when the working mode is
 * empty (= 0), we know we've looked at all the AoI. The second is
 * that the ACE interpretation rules don't allow a later ACE to undo
 * something granted or denied by an earlier ACE.  Removing the
 * discovered access or denial enforces this rule.  At the end of
 * processing the ACEs, all AoI that were found to be denied are
 * placed into the working_mode, giving the caller a mask of denied
 * accesses.  Returns:
 *      0               if all AoI granted
 *      EACCES          if the denied mask is non-zero
 *      other error     if abnormal failure (e.g., IO error)
 *
 * A secondary usage of the function is to determine if any of the
 * AoI are granted.  If an ACE grants any access in
 * the working_mode, we immediately short circuit out of the function.
 * This mode is chosen by setting anyaccess to B_TRUE.  The
 * working_mode is not a denied access mask upon exit if the function
 * is used in this manner.
 */
static int
zfs_zaccess_aces_check(znode_t *zp, uint32_t *working_mode,
    boolean_t anyaccess, cred_t *cr)
{
        zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
        zfs_acl_t       *aclp;
        int             error;
        uint64_t        who;            /* FUID from the ACE */
        uint16_t        type, iflags;
        uint16_t        entry_type;
        uint32_t        access_mask;
        uint32_t        deny_mask = 0;
        zfs_ace_hdr_t   *acep = NULL;
        boolean_t       checkit;        /* ACE ID matches */
        zfs_acl_iter_t  zai = {0};

        /*
         * This can be a HOT code path, so when possible
         * try to avoid entering z_acl_lock as writer.
         */
        rw_enter(&zp->z_acl_lock, RW_READER);
        aclp = zp->z_acl_cached;
        if (aclp == NULL) {
                /*
                 * OK, need WRITER to load the ACL.  Note:
                 * zfs_acl_node_read() re-checks zp->z_acl_cached
                 * and just returns if it's set.
                 */
                rw_exit(&zp->z_acl_lock);
                rw_enter(&zp->z_acl_lock, RW_WRITER);

                error = zfs_acl_node_read(zp, B_FALSE, &aclp, B_FALSE);
                if (error != 0) {
                        rw_exit(&zp->z_acl_lock);
                        return (error);
                }
                rw_downgrade(&zp->z_acl_lock);  /* now RW_READER */
                ASSERT(zp->z_acl_cached);
        }

        zai.zai_aclp = aclp;
        while (acep = zfs_acl_next_ace(&zai, acep, &who, &access_mask,
            &iflags, &type)) {
                uint32_t mask_matched;

                if (!zfs_acl_valid_ace_type(type, iflags))
                        continue;

                if (ZTOV(zp)->v_type == VDIR && (iflags & ACE_INHERIT_ONLY_ACE))
                        continue;

                /* Skip ACE if it does not affect any AoI */
                mask_matched = (access_mask & *working_mode);
                if (!mask_matched)
                        continue;

                entry_type = (iflags & ACE_TYPE_FLAGS);

                checkit = B_FALSE;

                switch (entry_type) {
                case ACE_OWNER:
                        who = zp->z_uid;
                        /*FALLTHROUGH*/
                case 0: /* USER Entry */
                        checkit = zfs_user_in_cred(zfsvfs, who, cr);
                        break;
                case OWNING_GROUP:
                        who = zp->z_gid;
                        /*FALLTHROUGH*/
                case ACE_IDENTIFIER_GROUP:
                        checkit = zfs_groupmember(zfsvfs, who, cr);
                        break;
                case ACE_EVERYONE:
                        checkit = B_TRUE;
                        break;

                default:
                        /*
                         * The zfs_acl_valid_ace_type check above
                         * should make this case impossible.
                         */
                        rw_exit(&zp->z_acl_lock);
                        return (SET_ERROR(EIO));
                }

                if (checkit) {
                        if (type == DENY) {
                                DTRACE_PROBE3(zfs__ace__denies,
                                    znode_t *, zp,
                                    zfs_ace_hdr_t *, acep,
                                    uint32_t, mask_matched);
                                deny_mask |= mask_matched;
                        } else {
                                DTRACE_PROBE3(zfs__ace__allows,
                                    znode_t *, zp,
                                    zfs_ace_hdr_t *, acep,
                                    uint32_t, mask_matched);
                                if (anyaccess) {
                                        rw_exit(&zp->z_acl_lock);
                                        return (0);
                                }
                        }
                        *working_mode &= ~mask_matched;
                }

                /* Are we done? */
                if (*working_mode == 0)
                        break;
        }

        rw_exit(&zp->z_acl_lock);

        /* Put the found 'denies' back on the working mode */
        if (deny_mask) {
                *working_mode |= deny_mask;
                return (SET_ERROR(EACCES));
        } else if (*working_mode) {
                return (-1);
        }

        return (0);
}

/*
 * Return true if any access whatsoever granted, we don't actually
 * care what access is granted.
 */
boolean_t
zfs_has_access(znode_t *zp, cred_t *cr)
{
        uint32_t have = ACE_ALL_PERMS;

        if (zfs_zaccess_aces_check(zp, &have, B_TRUE, cr) != 0) {
                uid_t owner;

                owner = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_uid, cr, ZFS_OWNER);
                return (secpolicy_vnode_any_access(cr, ZTOV(zp), owner) == 0);
        }
        return (B_TRUE);
}

static int
zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
    boolean_t *check_privs, boolean_t skipaclchk, cred_t *cr)
{
        zfsvfs_t *zfsvfs = zp->z_zfsvfs;
        int err;

        *working_mode = v4_mode;
        *check_privs = B_TRUE;

        /*
         * Short circuit empty requests
         */
        if (v4_mode == 0 || zfsvfs->z_replay) {
                *working_mode = 0;
                return (0);
        }

        if ((err = zfs_zaccess_dataset_check(zp, v4_mode)) != 0) {
                *check_privs = B_FALSE;
                return (err);
        }

        /*
         * The caller requested that the ACL check be skipped.  This
         * would only happen if the caller checked VOP_ACCESS() with a
         * 32 bit ACE mask and already had the appropriate permissions.
         */
        if (skipaclchk) {
                *working_mode = 0;
                return (0);
        }

        /*
         * Note: ZFS_READONLY represents the "DOS R/O" attribute.
         * When that flag is set, we should behave as if write access
         * were not granted by anything in the ACL.  In particular:
         * We _must_ allow writes after opening the file r/w, then
         * setting the DOS R/O attribute, and writing some more.
         * (Similar to how you can write after fchmod(fd, 0444).)
         *
         * Therefore ZFS_READONLY is ignored in the dataset check
         * above, and checked here as if part of the ACL check.
         * Also note: DOS R/O is ignored for directories.
         */
        if ((v4_mode & WRITE_MASK_DATA) &&
            (ZTOV(zp)->v_type != VDIR) &&
            (zp->z_pflags & ZFS_READONLY)) {
                return (SET_ERROR(EPERM));
        }

        return (zfs_zaccess_aces_check(zp, working_mode, B_FALSE, cr));
}

static int
zfs_zaccess_append(znode_t *zp, uint32_t *working_mode, boolean_t *check_privs,
    cred_t *cr)
{
        if (*working_mode != ACE_WRITE_DATA)
                return (SET_ERROR(EACCES));

        return (zfs_zaccess_common(zp, ACE_APPEND_DATA, working_mode,
            check_privs, B_FALSE, cr));
}

int
zfs_fastaccesschk_execute(znode_t *zdp, cred_t *cr, boolean_t skipaclchk)
{
        boolean_t owner = B_FALSE;
        boolean_t groupmbr = B_FALSE;
        boolean_t is_attr;
        uid_t uid = crgetuid(cr);
        int error;

        if (zdp->z_pflags & ZFS_AV_QUARANTINED)
                return (SET_ERROR(EACCES));

        is_attr = ((zdp->z_pflags & ZFS_XATTR) &&
            (ZTOV(zdp)->v_type == VDIR));
        if (is_attr)
                goto slow;


        rw_enter(&zdp->z_acl_lock, RW_READER);

        if (zdp->z_pflags & ZFS_NO_EXECS_DENIED) {
                rw_exit(&zdp->z_acl_lock);
                return (0);
        }

        if (FUID_INDEX(zdp->z_uid) != 0 || FUID_INDEX(zdp->z_gid) != 0) {
                rw_exit(&zdp->z_acl_lock);
                goto slow;
        }

        if (uid == zdp->z_uid) {
                owner = B_TRUE;
                if (zdp->z_mode & S_IXUSR) {
                        rw_exit(&zdp->z_acl_lock);
                        return (0);
                } else {
                        rw_exit(&zdp->z_acl_lock);
                        goto slow;
                }
        }
        if (groupmember(zdp->z_gid, cr)) {
                groupmbr = B_TRUE;
                if (zdp->z_mode & S_IXGRP) {
                        rw_exit(&zdp->z_acl_lock);
                        return (0);
                } else {
                        rw_exit(&zdp->z_acl_lock);
                        goto slow;
                }
        }
        if (!owner && !groupmbr) {
                if (zdp->z_mode & S_IXOTH) {
                        rw_exit(&zdp->z_acl_lock);
                        return (0);
                }
        }

        rw_exit(&zdp->z_acl_lock);

slow:
        DTRACE_PROBE(zfs__fastpath__execute__access__miss);
        ZFS_ENTER(zdp->z_zfsvfs);
        error = zfs_zaccess(zdp, ACE_EXECUTE, 0, skipaclchk, cr);
        ZFS_EXIT(zdp->z_zfsvfs);
        return (error);
}

/*
 * Determine whether Access should be granted/denied.
 *
 * The least priv subsystem is always consulted as a basic privilege
 * can define any form of access.
 *
 * Note that this function is called VERY frequently, and therefore
 * has some careful optimizations of what it does.  In particular,
 * a few places avoid calling zfs_fuid_map_id() when possible.
 */
int
zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr)
{
        uint32_t        working_mode;
        int             error;
        int             is_attr;
        boolean_t       check_privs;
        znode_t         *xzp;
        znode_t         *check_zp = zp;
        mode_t          needed_bits;
        uid_t           owner;

        is_attr = ((zp->z_pflags & ZFS_XATTR) && (ZTOV(zp)->v_type == VDIR));

        /*
         * If attribute then validate against base file
         */
        if (is_attr) {
                uint64_t        parent;

                if ((error = sa_lookup(zp->z_sa_hdl,
                    SA_ZPL_PARENT(zp->z_zfsvfs), &parent,
                    sizeof (parent))) != 0)
                        return (error);

                if ((error = zfs_zget(zp->z_zfsvfs,
                    parent, &xzp)) != 0)        {
                        return (error);
                }

                check_zp = xzp;

                /*
                 * fixup mode to map to xattr perms
                 */

                if (mode & (ACE_WRITE_DATA|ACE_APPEND_DATA)) {
                        mode &= ~(ACE_WRITE_DATA|ACE_APPEND_DATA);
                        mode |= ACE_WRITE_NAMED_ATTRS;
                }

                if (mode & (ACE_READ_DATA|ACE_EXECUTE)) {
                        mode &= ~(ACE_READ_DATA|ACE_EXECUTE);
                        mode |= ACE_READ_NAMED_ATTRS;
                }
        }

        /*
         * Map the bits required to the standard vnode flags VREAD|VWRITE|VEXEC
         * in needed_bits.  Map the bits mapped by working_mode (currently
         * missing) in missing_bits.
         * Call secpolicy_vnode_access2() with (needed_bits & ~checkmode),
         * needed_bits.
         */
        needed_bits = 0;

        working_mode = mode;

        /*
         * If we were not concerned with performance here, we could
         * just always get the file owner immediately as follows:
         *   owner = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_uid, cr, ZFS_OWNER);
         * However, that can cause a kidmap call (idmap up-call) in this
         * very hot code path so this tries to avoid that when possible.
         * For example, instead of (owner == crgetuid(cr))
         * this uses zfs_fuid_is_cruser() just below.
         *
         * Also note: With skipaclchk = TRUE, we're working with an
         * open handle so we know we're allowed to read ACL or attrs.
         * This can affect needed_bits below.
         */
        if ((working_mode & (ACE_READ_ACL|ACE_READ_ATTRIBUTES)) &&
            (skipaclchk || zfs_fuid_is_cruser(zp->z_zfsvfs, zp->z_uid, cr))) {
                working_mode &= ~(ACE_READ_ACL|ACE_READ_ATTRIBUTES);
        }

        if (working_mode & (ACE_READ_DATA|ACE_READ_NAMED_ATTRS|
            ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_SYNCHRONIZE))
                needed_bits |= VREAD;
        if (working_mode & (ACE_WRITE_DATA|ACE_WRITE_NAMED_ATTRS|
            ACE_APPEND_DATA|ACE_WRITE_ATTRIBUTES|ACE_SYNCHRONIZE))
                needed_bits |= VWRITE;
        if (working_mode & ACE_EXECUTE)
                needed_bits |= VEXEC;

        if ((error = zfs_zaccess_common(check_zp, mode, &working_mode,
            &check_privs, skipaclchk, cr)) == 0) {
                uid_t root_owned;

                if (is_attr)
                        VN_RELE(ZTOV(xzp));

                /*
                 * The call to secpolicy_vnode_access2() below normally
                 * wants the file owner UID in its third argument.
                 * Getting that UID here requires a kidmap call that
                 * we'd rather avoid due to its potential expense.
                 * The file owner UID is unused in that function when
                 * the last two arguments (curmode,wantmode) are equal,
                 * and otherwise is used only to test if the file is
                 * owned by root (UID == zero).  It does not actually
                 * use the UID value other than that, so we can pass
                 * anything other than zero when not owned by root.
                 * The local "root_owned" is the UID value we pass.
                 *
                 * If secpolicy_vnode_access2() changes to need the
                 * real owner UID here, this will need work.
                 */
                if (zp->z_uid == FUID_ENCODE(0, 0))
                        root_owned = 0; /* yes, owned by root */
                else
                        root_owned = (uid_t)-1;

                return (secpolicy_vnode_access2(cr, ZTOV(zp), root_owned,
                    needed_bits, needed_bits));
        }

        if (error && !check_privs) {
                if (is_attr)
                        VN_RELE(ZTOV(xzp));
                return (error);
        }

        if (error && (flags & V_APPEND)) {
                error = zfs_zaccess_append(zp, &working_mode, &check_privs, cr);
        }

        /*
         * The remaining code in this function is reached less frequently,
         * so it's OK to go ahead and get the real owner etc.
         */
        owner = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_uid, cr, ZFS_OWNER);

        if (error && check_privs) {
                mode_t          checkmode = 0;

                /*
                 * First check for implicit owner permission on
                 * read_acl/read_attributes
                 */

                error = 0;
                ASSERT(working_mode != 0);

                if ((working_mode & (ACE_READ_ACL|ACE_READ_ATTRIBUTES) &&
                    owner == crgetuid(cr)))
                        working_mode &= ~(ACE_READ_ACL|ACE_READ_ATTRIBUTES);

                if (working_mode & (ACE_READ_DATA|ACE_READ_NAMED_ATTRS|
                    ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_SYNCHRONIZE))
                        checkmode |= VREAD;
                if (working_mode & (ACE_WRITE_DATA|ACE_WRITE_NAMED_ATTRS|
                    ACE_APPEND_DATA|ACE_WRITE_ATTRIBUTES|ACE_SYNCHRONIZE))
                        checkmode |= VWRITE;
                if (working_mode & ACE_EXECUTE)
                        checkmode |= VEXEC;

                error = secpolicy_vnode_access2(cr, ZTOV(check_zp), owner,
                    needed_bits & ~checkmode, needed_bits);

                if (error == 0 && (working_mode & ACE_WRITE_OWNER))
                        error = secpolicy_vnode_chown(cr, owner);
                if (error == 0 && (working_mode & ACE_WRITE_ACL))
                        error = secpolicy_vnode_setdac3(cr, owner,
                            zp->z_zfsvfs->z_acl_implicit);

                if (error == 0 && (working_mode &
                    (ACE_DELETE|ACE_DELETE_CHILD)))
                        error = secpolicy_vnode_remove(cr);

                if (error == 0 && (working_mode & ACE_SYNCHRONIZE)) {
                        error = secpolicy_vnode_chown(cr, owner);
                }
                if (error == 0) {
                        /*
                         * See if any bits other than those already checked
                         * for are still present.  If so then return EACCES
                         */
                        if (working_mode & ~(ZFS_CHECKED_MASKS)) {
                                error = SET_ERROR(EACCES);
                        }
                }
        } else if (error == 0) {
                error = secpolicy_vnode_access2(cr, ZTOV(zp), owner,
                    needed_bits, needed_bits);
        }


        if (is_attr)
                VN_RELE(ZTOV(xzp));

        return (error);
}

/*
 * Translate traditional unix VREAD/VWRITE/VEXEC mode into
 * native ACL format and call zfs_zaccess()
 */
int
zfs_zaccess_rwx(znode_t *zp, mode_t mode, int flags, cred_t *cr)
{
        return (zfs_zaccess(zp, zfs_unix_to_v4(mode >> 6), flags, B_FALSE, cr));
}

/*
 * Access function for secpolicy_vnode_setattr
 */
int
zfs_zaccess_unix(znode_t *zp, mode_t mode, cred_t *cr)
{
        int v4_mode = zfs_unix_to_v4(mode >> 6);

        return (zfs_zaccess(zp, v4_mode, 0, B_FALSE, cr));
}

/* See zfs_zaccess_delete() */
int zfs_write_implies_delete_child = 1;

/*
 * Determine whether delete access should be granted.
 *
 * The following chart outlines how we handle delete permissions which is
 * how recent versions of windows (Windows 2008) handles it.  The efficiency
 * comes from not having to check the parent ACL where the object itself grants
 * delete:
 *
 *      -------------------------------------------------------
 *      |   Parent Dir  |      Target Object Permissions      |
 *      |  permissions  |                                     |
 *      -------------------------------------------------------
 *      |               | ACL Allows | ACL Denies| Delete     |
 *      |               |  Delete    |  Delete   | unspecified|
 *      -------------------------------------------------------
 *      | ACL Allows    | Permit     | Deny *    | Permit     |
 *      | DELETE_CHILD  |            |           |            |
 *      -------------------------------------------------------
 *      | ACL Denies    | Permit     | Deny      | Deny       |
 *      | DELETE_CHILD  |            |           |            |
 *      -------------------------------------------------------
 *      | ACL specifies |            |           |            |
 *      | only allow    | Permit     | Deny *    | Permit     |
 *      | write and     |            |           |            |
 *      | execute       |            |           |            |
 *      -------------------------------------------------------
 *      | ACL denies    |            |           |            |
 *      | write and     | Permit     | Deny      | Deny       |
 *      | execute       |            |           |            |
 *      -------------------------------------------------------
 *         ^
 *         |
 *         Re. execute permission on the directory:  if that's missing,
 *         the vnode lookup of the target will fail before we get here.
 *
 * Re [*] in the table above:  NFSv4 would normally Permit delete for
 * these two cells of the matrix.
 * See acl.h for notes on which ACE_... flags should be checked for which
 * operations.  Specifically, the NFSv4 committee recommendation is in
 * conflict with the Windows interpretation of DENY ACEs, where DENY ACEs
 * should take precedence ahead of ALLOW ACEs.
 *
 * This implementation always consults the target object's ACL first.
 * If a DENY ACE is present on the target object that specifies ACE_DELETE,
 * delete access is denied.  If an ALLOW ACE with ACE_DELETE is present on
 * the target object, access is allowed.  If and only if no entries with
 * ACE_DELETE are present in the object's ACL, check the container's ACL
 * for entries with ACE_DELETE_CHILD.
 *
 * A summary of the logic implemented from the table above is as follows:
 *
 * First check for DENY ACEs that apply.
 * If either target or container has a deny, EACCES.
 *
 * Delete access can then be summarized as follows:
 * 1: The object to be deleted grants ACE_DELETE, or
 * 2: The containing directory grants ACE_DELETE_CHILD.
 * In a Windows system, that would be the end of the story.
 * In this system, (2) has some complications...
 * 2a: "sticky" bit on a directory adds restrictions, and
 * 2b: existing ACEs from previous versions of ZFS may
 * not carry ACE_DELETE_CHILD where they should, so we
 * also allow delete when ACE_WRITE_DATA is granted.
 *
 * Note: 2b is technically a work-around for a prior bug,
 * which hopefully can go away some day.  For those who
 * no longer need the work around, and for testing, this
 * work-around is made conditional via the tunable:
 * zfs_write_implies_delete_child
 */
int
zfs_zaccess_delete(znode_t *dzp, znode_t *zp, cred_t *cr)
{
        uint32_t wanted_dirperms;
        uint32_t dzp_working_mode = 0;
        uint32_t zp_working_mode = 0;
        int dzp_error, zp_error;
        boolean_t dzpcheck_privs;
        boolean_t zpcheck_privs;

        if (zp->z_pflags & (ZFS_IMMUTABLE | ZFS_NOUNLINK))
                return (SET_ERROR(EPERM));

        /*
         * Case 1:
         * If target object grants ACE_DELETE then we are done.  This is
         * indicated by a return value of 0.  For this case we don't worry
         * about the sticky bit because sticky only applies to the parent
         * directory and this is the child access result.
         *
         * If we encounter a DENY ACE here, we're also done (EACCES).
         * Note that if we hit a DENY ACE here (on the target) it should
         * take precedence over a DENY ACE on the container, so that when
         * we have more complete auditing support we will be able to
         * report an access failure against the specific target.
         * (This is part of why we're checking the target first.)
         */
        zp_error = zfs_zaccess_common(zp, ACE_DELETE, &zp_working_mode,
            &zpcheck_privs, B_FALSE, cr);
        if (zp_error == EACCES) {
                /* We hit a DENY ACE. */
                if (!zpcheck_privs)
                        return (SET_ERROR(zp_error));
                return (secpolicy_vnode_remove(cr));

        }
        if (zp_error == 0)
                return (0);

        /*
         * Case 2:
         * If the containing directory grants ACE_DELETE_CHILD,
         * or we're in backward compatibility mode and the
         * containing directory has ACE_WRITE_DATA, allow.
         * Case 2b is handled with wanted_dirperms.
         */
        wanted_dirperms = ACE_DELETE_CHILD;
        if (zfs_write_implies_delete_child)
                wanted_dirperms |= ACE_WRITE_DATA;
        dzp_error = zfs_zaccess_common(dzp, wanted_dirperms,
            &dzp_working_mode, &dzpcheck_privs, B_FALSE, cr);
        if (dzp_error == EACCES) {
                /* We hit a DENY ACE. */
                if (!dzpcheck_privs)
                        return (SET_ERROR(dzp_error));
                return (secpolicy_vnode_remove(cr));
        }

        /*
         * Cases 2a, 2b (continued)
         *
         * Note: dzp_working_mode now contains any permissions
         * that were NOT granted.  Therefore, if any of the
         * wanted_dirperms WERE granted, we will have:
         *   dzp_working_mode != wanted_dirperms
         * We're really asking if ANY of those permissions
         * were granted, and if so, grant delete access.
         */
        if (dzp_working_mode != wanted_dirperms)
                dzp_error = 0;

        /*
         * dzp_error is 0 if the container granted us permissions to "modify".
         * If we do not have permission via one or more ACEs, our current
         * privileges may still permit us to modify the container.
         *
         * dzpcheck_privs is false when i.e. the FS is read-only.
         * Otherwise, do privilege checks for the container.
         */
        if (dzp_error != 0 && dzpcheck_privs) {
                uid_t owner;

                /*
                 * The secpolicy call needs the requested access and
                 * the current access mode of the container, but it
                 * only knows about Unix-style modes (VEXEC, VWRITE),
                 * so this must condense the fine-grained ACE bits into
                 * Unix modes.
                 *
                 * The VEXEC flag is easy, because we know that has
                 * always been checked before we get here (during the
                 * lookup of the target vnode).  The container has not
                 * granted us permissions to "modify", so we do not set
                 * the VWRITE flag in the current access mode.
                 */
                owner = zfs_fuid_map_id(dzp->z_zfsvfs, dzp->z_uid, cr,
                    ZFS_OWNER);
                dzp_error = secpolicy_vnode_access2(cr, ZTOV(dzp),
                    owner, VEXEC, VWRITE|VEXEC);
        }
        if (dzp_error != 0) {
                /*
                 * Note: We may have dzp_error = -1 here (from
                 * zfs_zacess_common).  Don't return that.
                 */
                return (SET_ERROR(EACCES));
        }

        /*
         * At this point, we know that the directory permissions allow
         * us to modify, but we still need to check for the additional
         * restrictions that apply when the "sticky bit" is set.
         *
         * Yes, zfs_sticky_remove_access() also checks this bit, but
         * checking it here and skipping the call below is nice when
         * you're watching all of this with dtrace.
         */
        if ((dzp->z_mode & S_ISVTX) == 0)
                return (0);

        /*
         * zfs_sticky_remove_access will succeed if:
         * 1. The sticky bit is absent.
         * 2. We pass the sticky bit restrictions.
         * 3. We have privileges that always allow file removal.
         */
        return (zfs_sticky_remove_access(dzp, zp, cr));
}

int
zfs_zaccess_rename(znode_t *sdzp, znode_t *szp, znode_t *tdzp,
    znode_t *tzp, cred_t *cr)
{
        int add_perm;
        int error;

        if (szp->z_pflags & ZFS_AV_QUARANTINED)
                return (SET_ERROR(EACCES));

        add_perm = (ZTOV(szp)->v_type == VDIR) ?
            ACE_ADD_SUBDIRECTORY : ACE_ADD_FILE;

        /*
         * Rename permissions are combination of delete permission +
         * add file/subdir permission.
         */

        /*
         * first make sure we do the delete portion.
         *
         * If that succeeds then check for add_file/add_subdir permissions
         */

        if (error = zfs_zaccess_delete(sdzp, szp, cr))
                return (error);

        /*
         * If we have a tzp, see if we can delete it?
         */
        if (tzp) {
                if (error = zfs_zaccess_delete(tdzp, tzp, cr))
                        return (error);
        }

        /*
         * Now check for add permissions
         */
        error = zfs_zaccess(tdzp, add_perm, 0, B_FALSE, cr);

        return (error);
}