/*
 *  Server-side XDR for NFSv4
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/file.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/utsname.h>
#include <linux/pagemap.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/addr.h>
#include <linux/xattr.h>
#include <linux/vmalloc.h>
#include <linux/nfsacl.h>

#include <uapi/linux/xattr.h>

#include "idmap.h"
#include "acl.h"
#include "xdr4.h"
#include "vfs.h"
#include "state.h"
#include "cache.h"
#include "netns.h"
#include "pnfs.h"
#include "filecache.h"
#include "nfs4xdr_gen.h"

#include "trace.h"

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
#include <linux/security.h>
#endif


#define NFSDDBG_FACILITY                NFSDDBG_XDR

const u32 nfsd_suppattrs[3][3] = {
        {NFSD4_SUPPORTED_ATTRS_WORD0,
         NFSD4_SUPPORTED_ATTRS_WORD1,
         NFSD4_SUPPORTED_ATTRS_WORD2},

        {NFSD4_1_SUPPORTED_ATTRS_WORD0,
         NFSD4_1_SUPPORTED_ATTRS_WORD1,
         NFSD4_1_SUPPORTED_ATTRS_WORD2},

        {NFSD4_1_SUPPORTED_ATTRS_WORD0,
         NFSD4_1_SUPPORTED_ATTRS_WORD1,
         NFSD4_2_SUPPORTED_ATTRS_WORD2},
};

/*
 * As per referral draft, the fsid for a referral MUST be different from the fsid of the containing
 * directory in order to indicate to the client that a filesystem boundary is present
 * We use a fixed fsid for a referral
 */
#define NFS4_REFERRAL_FSID_MAJOR        0x8000000ULL
#define NFS4_REFERRAL_FSID_MINOR        0x8000000ULL

static __be32
check_filename(char *str, int len)
{
        int i;

        if (len == 0)
                return nfserr_inval;
        if (len > NFS4_MAXNAMLEN)
                return nfserr_nametoolong;
        if (isdotent(str, len))
                return nfserr_badname;
        for (i = 0; i < len; i++)
                if (str[i] == '/')
                        return nfserr_badname;
        return 0;
}

static int zero_clientid(clientid_t *clid)
{
        return (clid->cl_boot == 0) && (clid->cl_id == 0);
}

/**
 * svcxdr_tmpalloc - allocate memory to be freed after compound processing
 * @argp: NFSv4 compound argument structure
 * @len: length of buffer to allocate
 *
 * Allocates a buffer of size @len to be freed when processing the compound
 * operation described in @argp finishes.
 */
static void *
svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, size_t len)
{
        struct svcxdr_tmpbuf *tb;

        tb = kmalloc_flex(*tb, buf, len);
        if (!tb)
                return NULL;
        tb->next = argp->to_free;
        argp->to_free = tb;
        return tb->buf;
}

/*
 * For xdr strings that need to be passed to other kernel api's
 * as null-terminated strings.
 *
 * Note null-terminating in place usually isn't safe since the
 * buffer might end on a page boundary.
 */
static char *
svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, size_t len)
{
        char *p = svcxdr_tmpalloc(argp, size_add(len, 1));

        if (!p)
                return NULL;
        memcpy(p, buf, len);
        p[len] = '\0';
        return p;
}

static void *
svcxdr_savemem(struct nfsd4_compoundargs *argp, __be32 *p, size_t len)
{
        __be32 *tmp;

        /*
         * The location of the decoded data item is stable,
         * so @p is OK to use. This is the common case.
         */
        if (p != argp->xdr->scratch.iov_base)
                return p;

        tmp = svcxdr_tmpalloc(argp, len);
        if (!tmp)
                return NULL;
        memcpy(tmp, p, len);
        return tmp;
}

/*
 * NFSv4 basic data type decoders
 */

/*
 * This helper handles variable-length opaques which belong to protocol
 * elements that this implementation does not support.
 */
static __be32
nfsd4_decode_ignored_string(struct nfsd4_compoundargs *argp, u32 maxlen)
{
        u32 len;

        if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
                return nfserr_bad_xdr;
        if (maxlen && len > maxlen)
                return nfserr_bad_xdr;
        if (!xdr_inline_decode(argp->xdr, len))
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_netobj *o)
{
        __be32 *p;
        u32 len;

        if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
                return nfserr_bad_xdr;
        if (len == 0 || len > NFS4_OPAQUE_LIMIT)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, len);
        if (!p)
                return nfserr_bad_xdr;
        o->data = svcxdr_savemem(argp, p, len);
        if (!o->data)
                return nfserr_jukebox;
        o->len = len;

        return nfs_ok;
}

static __be32
nfsd4_decode_component4(struct nfsd4_compoundargs *argp, char **namp, u32 *lenp)
{
        __be32 *p, status;

        if (xdr_stream_decode_u32(argp->xdr, lenp) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, *lenp);
        if (!p)
                return nfserr_bad_xdr;
        status = check_filename((char *)p, *lenp);
        if (status)
                return status;
        *namp = svcxdr_savemem(argp, p, *lenp);
        if (!*namp)
                return nfserr_jukebox;

        return nfs_ok;
}

static __be32
nfsd4_decode_nfstime4(struct nfsd4_compoundargs *argp, struct timespec64 *tv)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, XDR_UNIT * 3);
        if (!p)
                return nfserr_bad_xdr;
        p = xdr_decode_hyper(p, &tv->tv_sec);
        tv->tv_nsec = be32_to_cpup(p++);
        if (tv->tv_nsec >= (u32)1000000000)
                return nfserr_inval;
        return nfs_ok;
}

static __be32
nfsd4_decode_verifier4(struct nfsd4_compoundargs *argp, nfs4_verifier *verf)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, NFS4_VERIFIER_SIZE);
        if (!p)
                return nfserr_bad_xdr;
        memcpy(verf->data, p, sizeof(verf->data));
        return nfs_ok;
}

/**
 * nfsd4_decode_bitmap4 - Decode an NFSv4 bitmap4
 * @argp: NFSv4 compound argument structure
 * @bmval: pointer to an array of u32's to decode into
 * @bmlen: size of the @bmval array
 *
 * The server needs to return nfs_ok rather than nfserr_bad_xdr when
 * encountering bitmaps containing bits it does not recognize. This
 * includes bits in bitmap words past WORDn, where WORDn is the last
 * bitmap WORD the implementation currently supports. Thus we are
 * careful here to simply ignore bits in bitmap words that this
 * implementation has yet to support explicitly.
 *
 * Return values:
 *   %nfs_ok: @bmval populated successfully
 *   %nfserr_bad_xdr: the encoded bitmap was invalid
 */
static __be32
nfsd4_decode_bitmap4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen)
{
        ssize_t status;

        status = xdr_stream_decode_uint32_array(argp->xdr, bmval, bmlen);
        return status == -EBADMSG ? nfserr_bad_xdr : nfs_ok;
}

static __be32
nfsd4_decode_nfsace4(struct nfsd4_compoundargs *argp, struct nfs4_ace *ace)
{
        __be32 *p, status;
        u32 length;

        if (xdr_stream_decode_u32(argp->xdr, &ace->type) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &ace->flag) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &ace->access_mask) < 0)
                return nfserr_bad_xdr;

        if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, length);
        if (!p)
                return nfserr_bad_xdr;
        ace->whotype = nfs4_acl_get_whotype((char *)p, length);
        if (ace->whotype != NFS4_ACL_WHO_NAMED)
                status = nfs_ok;
        else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                status = nfsd_map_name_to_gid(argp->rqstp,
                                (char *)p, length, &ace->who_gid);
        else
                status = nfsd_map_name_to_uid(argp->rqstp,
                                (char *)p, length, &ace->who_uid);

        return status;
}

/* A counted array of nfsace4's */
static noinline __be32
nfsd4_decode_acl(struct nfsd4_compoundargs *argp, struct nfs4_acl **acl)
{
        struct nfs4_ace *ace;
        __be32 status;
        u32 count;

        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;

        if (count > xdr_stream_remaining(argp->xdr) / 20)
                /*
                 * Even with 4-byte names there wouldn't be
                 * space for that many aces; something fishy is
                 * going on:
                 */
                return nfserr_fbig;

        *acl = svcxdr_tmpalloc(argp, nfs4_acl_bytes(count));
        if (*acl == NULL)
                return nfserr_jukebox;

        (*acl)->naces = count;
        for (ace = (*acl)->aces; ace < (*acl)->aces + count; ace++) {
                status = nfsd4_decode_nfsace4(argp, ace);
                if (status)
                        return status;
        }

        return nfs_ok;
}

static noinline __be32
nfsd4_decode_security_label(struct nfsd4_compoundargs *argp,
                            struct xdr_netobj *label)
{
        u32 lfs, pi, length;
        __be32 *p;

        if (xdr_stream_decode_u32(argp->xdr, &lfs) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &pi) < 0)
                return nfserr_bad_xdr;

        if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
                return nfserr_bad_xdr;
        if (length > NFS4_MAXLABELLEN)
                return nfserr_badlabel;
        p = xdr_inline_decode(argp->xdr, length);
        if (!p)
                return nfserr_bad_xdr;
        label->len = length;
        label->data = svcxdr_dupstr(argp, p, length);
        if (!label->data)
                return nfserr_jukebox;

        return nfs_ok;
}

#ifdef CONFIG_NFSD_V4_POSIX_ACLS

static short nfsd4_posixacetag4_to_tag(posixacetag4 tag)
{
        switch (tag) {
        case POSIXACE4_TAG_USER_OBJ:    return ACL_USER_OBJ;
        case POSIXACE4_TAG_GROUP_OBJ:   return ACL_GROUP_OBJ;
        case POSIXACE4_TAG_USER:        return ACL_USER;
        case POSIXACE4_TAG_GROUP:       return ACL_GROUP;
        case POSIXACE4_TAG_MASK:        return ACL_MASK;
        case POSIXACE4_TAG_OTHER:       return ACL_OTHER;
        }
        return ACL_OTHER;
}

static __be32
nfsd4_decode_posixace4(struct nfsd4_compoundargs *argp,
                       struct posix_acl_entry *ace)
{
        posixaceperm4 perm;
        __be32 *p, status;
        posixacetag4 tag;
        u32 len;

        if (!xdrgen_decode_posixacetag4(argp->xdr, &tag))
                return nfserr_bad_xdr;
        ace->e_tag = nfsd4_posixacetag4_to_tag(tag);

        if (!xdrgen_decode_posixaceperm4(argp->xdr, &perm))
                return nfserr_bad_xdr;
        if (perm & ~S_IRWXO)
                return nfserr_bad_xdr;
        ace->e_perm = perm;

        if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, len);
        if (!p)
                return nfserr_bad_xdr;
        switch (tag) {
        case POSIXACE4_TAG_USER:
                if (len > 0)
                        status = nfsd_map_name_to_uid(argp->rqstp,
                                        (char *)p, len, &ace->e_uid);
                else
                        status = nfserr_bad_xdr;
                break;
        case POSIXACE4_TAG_GROUP:
                if (len > 0)
                        status = nfsd_map_name_to_gid(argp->rqstp,
                                        (char *)p, len, &ace->e_gid);
                else
                        status = nfserr_bad_xdr;
                break;
        default:
                status = nfs_ok;
        }

        return status;
}

static noinline __be32
nfsd4_decode_posixacl(struct nfsd4_compoundargs *argp, struct posix_acl **acl)
{
        struct posix_acl_entry *ace;
        __be32 status;
        u32 count;

        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;

        *acl = posix_acl_alloc(count, GFP_KERNEL);
        if (*acl == NULL)
                return nfserr_resource;

        (*acl)->a_count = count;
        for (ace = (*acl)->a_entries; ace < (*acl)->a_entries + count; ace++) {
                status = nfsd4_decode_posixace4(argp, ace);
                if (status) {
                        posix_acl_release(*acl);
                        *acl = NULL;
                        return status;
                }
        }

        /*
         * posix_acl_valid() requires the ACEs to be sorted.
         * If they are already sorted, sort_pacl_range() will return
         * after one pass through the ACEs, since it implements bubble sort.
         * Note that a count == 0 is used to delete a POSIX ACL and a count
         * of 1 or 2 will always be found invalid by posix_acl_valid().
         */
        if (count >= 3)
                sort_pacl_range(*acl, 0, count - 1);

        return nfs_ok;
}

#endif /* CONFIG_NFSD_V4_POSIX_ACLS */

static __be32
nfsd4_decode_fattr4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen,
                    struct iattr *iattr, struct nfs4_acl **acl,
                    struct xdr_netobj *label, int *umask,
                    struct posix_acl **dpaclp, struct posix_acl **paclp)
{
        unsigned int starting_pos;
        u32 attrlist4_count;
        __be32 *p, status;

        iattr->ia_valid = 0;
        status = nfsd4_decode_bitmap4(argp, bmval, bmlen);
        if (status)
                return nfserr_bad_xdr;

        if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
            || bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
            || bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2) {
                if (nfsd_attrs_supported(argp->minorversion, bmval))
                        return nfserr_inval;
                return nfserr_attrnotsupp;
        }

        if (xdr_stream_decode_u32(argp->xdr, &attrlist4_count) < 0)
                return nfserr_bad_xdr;
        starting_pos = xdr_stream_pos(argp->xdr);

        if (bmval[0] & FATTR4_WORD0_SIZE) {
                u64 size;

                if (xdr_stream_decode_u64(argp->xdr, &size) < 0)
                        return nfserr_bad_xdr;
                iattr->ia_size = size;
                iattr->ia_valid |= ATTR_SIZE;
        }
        if (bmval[0] & FATTR4_WORD0_ACL) {
                status = nfsd4_decode_acl(argp, acl);
                if (status)
                        return status;
        } else
                *acl = NULL;
        if (bmval[1] & FATTR4_WORD1_MODE) {
                u32 mode;

                if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
                        return nfserr_bad_xdr;
                iattr->ia_mode = mode;
                iattr->ia_mode &= (S_IFMT | S_IALLUGO);
                iattr->ia_valid |= ATTR_MODE;
        }
        if (bmval[1] & FATTR4_WORD1_OWNER) {
                u32 length;

                if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
                        return nfserr_bad_xdr;
                p = xdr_inline_decode(argp->xdr, length);
                if (!p)
                        return nfserr_bad_xdr;
                status = nfsd_map_name_to_uid(argp->rqstp, (char *)p, length,
                                              &iattr->ia_uid);
                if (status)
                        return status;
                iattr->ia_valid |= ATTR_UID;
        }
        if (bmval[1] & FATTR4_WORD1_OWNER_GROUP) {
                u32 length;

                if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
                        return nfserr_bad_xdr;
                p = xdr_inline_decode(argp->xdr, length);
                if (!p)
                        return nfserr_bad_xdr;
                status = nfsd_map_name_to_gid(argp->rqstp, (char *)p, length,
                                              &iattr->ia_gid);
                if (status)
                        return status;
                iattr->ia_valid |= ATTR_GID;
        }
        if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
                u32 set_it;

                if (xdr_stream_decode_u32(argp->xdr, &set_it) < 0)
                        return nfserr_bad_xdr;
                switch (set_it) {
                case NFS4_SET_TO_CLIENT_TIME:
                        status = nfsd4_decode_nfstime4(argp, &iattr->ia_atime);
                        if (status)
                                return status;
                        iattr->ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
                        break;
                case NFS4_SET_TO_SERVER_TIME:
                        iattr->ia_valid |= ATTR_ATIME;
                        break;
                default:
                        return nfserr_bad_xdr;
                }
        }
        if (bmval[1] & FATTR4_WORD1_TIME_CREATE) {
                struct timespec64 ts;

                /* No Linux filesystem supports setting this attribute. */
                bmval[1] &= ~FATTR4_WORD1_TIME_CREATE;
                status = nfsd4_decode_nfstime4(argp, &ts);
                if (status)
                        return status;
        }
        if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
                u32 set_it;

                if (xdr_stream_decode_u32(argp->xdr, &set_it) < 0)
                        return nfserr_bad_xdr;
                switch (set_it) {
                case NFS4_SET_TO_CLIENT_TIME:
                        status = nfsd4_decode_nfstime4(argp, &iattr->ia_mtime);
                        if (status)
                                return status;
                        iattr->ia_valid |= (ATTR_MTIME | ATTR_MTIME_SET);
                        break;
                case NFS4_SET_TO_SERVER_TIME:
                        iattr->ia_valid |= ATTR_MTIME;
                        break;
                default:
                        return nfserr_bad_xdr;
                }
        }
        label->len = 0;
        if (IS_ENABLED(CONFIG_NFSD_V4_SECURITY_LABEL) &&
            bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
                status = nfsd4_decode_security_label(argp, label);
                if (status)
                        return status;
        }
        if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
                u32 mode, mask;

                if (!umask)
                        return nfserr_bad_xdr;
                if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
                        return nfserr_bad_xdr;
                iattr->ia_mode = mode & (S_IFMT | S_IALLUGO);
                if (xdr_stream_decode_u32(argp->xdr, &mask) < 0)
                        return nfserr_bad_xdr;
                *umask = mask & S_IRWXUGO;
                iattr->ia_valid |= ATTR_MODE;
        }
        if (bmval[2] & FATTR4_WORD2_TIME_DELEG_ACCESS) {
                fattr4_time_deleg_access access;

                if (!xdrgen_decode_fattr4_time_deleg_access(argp->xdr, &access))
                        return nfserr_bad_xdr;
                iattr->ia_atime.tv_sec = access.seconds;
                iattr->ia_atime.tv_nsec = access.nseconds;
                iattr->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET | ATTR_DELEG;
        }
        if (bmval[2] & FATTR4_WORD2_TIME_DELEG_MODIFY) {
                fattr4_time_deleg_modify modify;

                if (!xdrgen_decode_fattr4_time_deleg_modify(argp->xdr, &modify))
                        return nfserr_bad_xdr;
                iattr->ia_mtime.tv_sec = modify.seconds;
                iattr->ia_mtime.tv_nsec = modify.nseconds;
                iattr->ia_ctime.tv_sec = modify.seconds;
                iattr->ia_ctime.tv_nsec = modify.nseconds;
                iattr->ia_valid |= ATTR_CTIME | ATTR_CTIME_SET |
                                   ATTR_MTIME | ATTR_MTIME_SET | ATTR_DELEG;
        }

        *dpaclp = NULL;
        *paclp = NULL;
#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        if (bmval[2] & FATTR4_WORD2_POSIX_DEFAULT_ACL) {
                struct posix_acl *dpacl;

                status = nfsd4_decode_posixacl(argp, &dpacl);
                if (status)
                        return status;
                *dpaclp = dpacl;
        }
        if (bmval[2] & FATTR4_WORD2_POSIX_ACCESS_ACL) {
                struct posix_acl *pacl;

                status = nfsd4_decode_posixacl(argp, &pacl);
                if (status) {
                        posix_acl_release(*dpaclp);
                        *dpaclp = NULL;
                        return status;
                }
                *paclp = pacl;
        }
#endif /* CONFIG_NFSD_V4_POSIX_ACLS */

        /* request sanity: did attrlist4 contain the expected number of words? */
        if (attrlist4_count != xdr_stream_pos(argp->xdr) - starting_pos) {
#ifdef CONFIG_NFSD_V4_POSIX_ACLS
                posix_acl_release(*dpaclp);
                posix_acl_release(*paclp);
                *dpaclp = NULL;
                *paclp = NULL;
#endif
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_stateid4(struct nfsd4_compoundargs *argp, stateid_t *sid)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, NFS4_STATEID_SIZE);
        if (!p)
                return nfserr_bad_xdr;
        sid->si_generation = be32_to_cpup(p++);
        memcpy(&sid->si_opaque, p, sizeof(sid->si_opaque));
        return nfs_ok;
}

static __be32
nfsd4_decode_clientid4(struct nfsd4_compoundargs *argp, clientid_t *clientid)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, sizeof(__be64));
        if (!p)
                return nfserr_bad_xdr;
        memcpy(clientid, p, sizeof(*clientid));
        return nfs_ok;
}

static __be32
nfsd4_decode_state_owner4(struct nfsd4_compoundargs *argp,
                          clientid_t *clientid, struct xdr_netobj *owner)
{
        __be32 status;

        status = nfsd4_decode_clientid4(argp, clientid);
        if (status)
                return status;
        return nfsd4_decode_opaque(argp, owner);
}

#ifdef CONFIG_NFSD_PNFS

static __be32
nfsd4_decode_layoutupdate4(struct nfsd4_compoundargs *argp,
                           struct nfsd4_layoutcommit *lcp)
{
        u32 len;

        if (xdr_stream_decode_u32(argp->xdr, &lcp->lc_layout_type) < 0)
                return nfserr_bad_xdr;
        if (lcp->lc_layout_type < LAYOUT_NFSV4_1_FILES)
                return nfserr_bad_xdr;
        if (lcp->lc_layout_type >= LAYOUT_TYPE_MAX)
                return nfserr_bad_xdr;

        if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
                return nfserr_bad_xdr;
        if (!xdr_stream_subsegment(argp->xdr, &lcp->lc_up_layout, len))
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_layoutreturn4(struct nfsd4_compoundargs *argp,
                           struct nfsd4_layoutreturn *lrp)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_return_type) < 0)
                return nfserr_bad_xdr;
        switch (lrp->lr_return_type) {
        case RETURN_FILE:
                if (xdr_stream_decode_u64(argp->xdr, &lrp->lr_seg.offset) < 0)
                        return nfserr_bad_xdr;
                if (xdr_stream_decode_u64(argp->xdr, &lrp->lr_seg.length) < 0)
                        return nfserr_bad_xdr;
                status = nfsd4_decode_stateid4(argp, &lrp->lr_sid);
                if (status)
                        return status;
                if (xdr_stream_decode_u32(argp->xdr, &lrp->lrf_body_len) < 0)
                        return nfserr_bad_xdr;
                if (lrp->lrf_body_len > 0) {
                        lrp->lrf_body = xdr_inline_decode(argp->xdr, lrp->lrf_body_len);
                        if (!lrp->lrf_body)
                                return nfserr_bad_xdr;
                }
                break;
        case RETURN_FSID:
        case RETURN_ALL:
                lrp->lr_seg.offset = 0;
                lrp->lr_seg.length = NFS4_MAX_UINT64;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

#endif /* CONFIG_NFSD_PNFS */

static __be32
nfsd4_decode_sessionid4(struct nfsd4_compoundargs *argp,
                        struct nfs4_sessionid *sessionid)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, NFS4_MAX_SESSIONID_LEN);
        if (!p)
                return nfserr_bad_xdr;
        memcpy(sessionid->data, p, sizeof(sessionid->data));
        return nfs_ok;
}

/* Defined in Appendix A of RFC 5531 */
static __be32
nfsd4_decode_authsys_parms(struct nfsd4_compoundargs *argp,
                           struct nfsd4_cb_sec *cbs)
{
        u32 stamp, gidcount, uid, gid;
        __be32 *p, status;

        if (xdr_stream_decode_u32(argp->xdr, &stamp) < 0)
                return nfserr_bad_xdr;
        /* machine name */
        status = nfsd4_decode_ignored_string(argp, 255);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &uid) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &gid) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &gidcount) < 0)
                return nfserr_bad_xdr;
        if (gidcount > 16)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, gidcount << 2);
        if (!p)
                return nfserr_bad_xdr;
        if (cbs->flavor == (u32)(-1)) {
                struct user_namespace *userns = nfsd_user_namespace(argp->rqstp);

                kuid_t kuid = make_kuid(userns, uid);
                kgid_t kgid = make_kgid(userns, gid);
                if (uid_valid(kuid) && gid_valid(kgid)) {
                        cbs->uid = kuid;
                        cbs->gid = kgid;
                        cbs->flavor = RPC_AUTH_UNIX;
                } else {
                        dprintk("RPC_AUTH_UNIX with invalid uid or gid, ignoring!\n");
                }
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_gss_cb_handles4(struct nfsd4_compoundargs *argp,
                             struct nfsd4_cb_sec *cbs)
{
        __be32 status;
        u32 service;

        dprintk("RPC_AUTH_GSS callback secflavor not supported!\n");

        if (xdr_stream_decode_u32(argp->xdr, &service) < 0)
                return nfserr_bad_xdr;
        if (service < RPC_GSS_SVC_NONE || service > RPC_GSS_SVC_PRIVACY)
                return nfserr_bad_xdr;
        /* gcbp_handle_from_server */
        status = nfsd4_decode_ignored_string(argp, 0);
        if (status)
                return status;
        /* gcbp_handle_from_client */
        status = nfsd4_decode_ignored_string(argp, 0);
        if (status)
                return status;

        return nfs_ok;
}

/* a counted array of callback_sec_parms4 items */
static __be32
nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_cb_sec *cbs)
{
        u32 i, secflavor, nr_secflavs;
        __be32 status;

        /* callback_sec_params4 */
        if (xdr_stream_decode_u32(argp->xdr, &nr_secflavs) < 0)
                return nfserr_bad_xdr;
        if (nr_secflavs)
                cbs->flavor = (u32)(-1);
        else
                /* Is this legal? Be generous, take it to mean AUTH_NONE: */
                cbs->flavor = 0;

        for (i = 0; i < nr_secflavs; ++i) {
                if (xdr_stream_decode_u32(argp->xdr, &secflavor) < 0)
                        return nfserr_bad_xdr;
                switch (secflavor) {
                case RPC_AUTH_NULL:
                        /* void */
                        if (cbs->flavor == (u32)(-1))
                                cbs->flavor = RPC_AUTH_NULL;
                        break;
                case RPC_AUTH_UNIX:
                        status = nfsd4_decode_authsys_parms(argp, cbs);
                        if (status)
                                return status;
                        break;
                case RPC_AUTH_GSS:
                        status = nfsd4_decode_gss_cb_handles4(argp, cbs);
                        if (status)
                                return status;
                        break;
                default:
                        return nfserr_inval;
                }
        }

        return nfs_ok;
}


/*
 * NFSv4 operation argument decoders
 */

static __be32
nfsd4_decode_access(struct nfsd4_compoundargs *argp,
                    union nfsd4_op_u *u)
{
        struct nfsd4_access *access = &u->access;
        if (xdr_stream_decode_u32(argp->xdr, &access->ac_req_access) < 0)
                return nfserr_bad_xdr;
        return nfs_ok;
}

static __be32
nfsd4_decode_close(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_close *close = &u->close;
        if (xdr_stream_decode_u32(argp->xdr, &close->cl_seqid) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_stateid4(argp, &close->cl_stateid);
}


static __be32
nfsd4_decode_commit(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_commit *commit = &u->commit;
        if (xdr_stream_decode_u64(argp->xdr, &commit->co_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &commit->co_count) < 0)
                return nfserr_bad_xdr;
        memset(&commit->co_verf, 0, sizeof(commit->co_verf));
        return nfs_ok;
}

static __be32
nfsd4_decode_create(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_create *create = &u->create;
        __be32 *p, status;

        memset(create, 0, sizeof(*create));
        if (xdr_stream_decode_u32(argp->xdr, &create->cr_type) < 0)
                return nfserr_bad_xdr;
        switch (create->cr_type) {
        case NF4LNK:
                if (xdr_stream_decode_u32(argp->xdr, &create->cr_datalen) < 0)
                        return nfserr_bad_xdr;
                p = xdr_inline_decode(argp->xdr, create->cr_datalen);
                if (!p)
                        return nfserr_bad_xdr;
                create->cr_data = svcxdr_dupstr(argp, p, create->cr_datalen);
                if (!create->cr_data)
                        return nfserr_jukebox;
                break;
        case NF4BLK:
        case NF4CHR:
                if (xdr_stream_decode_u32(argp->xdr, &create->cr_specdata1) < 0)
                        return nfserr_bad_xdr;
                if (xdr_stream_decode_u32(argp->xdr, &create->cr_specdata2) < 0)
                        return nfserr_bad_xdr;
                break;
        case NF4SOCK:
        case NF4FIFO:
        case NF4DIR:
        default:
                break;
        }
        status = nfsd4_decode_component4(argp, &create->cr_name,
                                         &create->cr_namelen);
        if (status)
                return status;
        status = nfsd4_decode_fattr4(argp, create->cr_bmval,
                                    ARRAY_SIZE(create->cr_bmval),
                                    &create->cr_iattr, &create->cr_acl,
                                    &create->cr_label, &create->cr_umask,
                                    &create->cr_dpacl, &create->cr_pacl);
        if (status)
                return status;

        return nfs_ok;
}

static inline __be32
nfsd4_decode_delegreturn(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_delegreturn *dr = &u->delegreturn;
        return nfsd4_decode_stateid4(argp, &dr->dr_stateid);
}

static inline __be32
nfsd4_decode_getattr(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_getattr *getattr = &u->getattr;
        memset(getattr, 0, sizeof(*getattr));
        return nfsd4_decode_bitmap4(argp, getattr->ga_bmval,
                                    ARRAY_SIZE(getattr->ga_bmval));
}

static __be32
nfsd4_decode_link(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_link *link = &u->link;
        memset(link, 0, sizeof(*link));
        return nfsd4_decode_component4(argp, &link->li_name, &link->li_namelen);
}

static __be32
nfsd4_decode_open_to_lock_owner4(struct nfsd4_compoundargs *argp,
                                 struct nfsd4_lock *lock)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &lock->lk_new_open_seqid) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_stateid4(argp, &lock->lk_new_open_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &lock->lk_new_lock_seqid) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_state_owner4(argp, &lock->lk_new_clientid,
                                         &lock->lk_new_owner);
}

static __be32
nfsd4_decode_exist_lock_owner4(struct nfsd4_compoundargs *argp,
                               struct nfsd4_lock *lock)
{
        __be32 status;

        status = nfsd4_decode_stateid4(argp, &lock->lk_old_lock_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &lock->lk_old_lock_seqid) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_locker4(struct nfsd4_compoundargs *argp, struct nfsd4_lock *lock)
{
        if (xdr_stream_decode_bool(argp->xdr, &lock->lk_is_new) < 0)
                return nfserr_bad_xdr;
        if (lock->lk_is_new)
                return nfsd4_decode_open_to_lock_owner4(argp, lock);
        return nfsd4_decode_exist_lock_owner4(argp, lock);
}

static __be32
nfsd4_decode_lock(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_lock *lock = &u->lock;
        memset(lock, 0, sizeof(*lock));
        if (xdr_stream_decode_u32(argp->xdr, &lock->lk_type) < 0)
                return nfserr_bad_xdr;
        if ((lock->lk_type < NFS4_READ_LT) || (lock->lk_type > NFS4_WRITEW_LT))
                return nfserr_bad_xdr;
        if (xdr_stream_decode_bool(argp->xdr, &lock->lk_reclaim) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lock->lk_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lock->lk_length) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_locker4(argp, lock);
}

static __be32
nfsd4_decode_lockt(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_lockt *lockt = &u->lockt;
        memset(lockt, 0, sizeof(*lockt));
        if (xdr_stream_decode_u32(argp->xdr, &lockt->lt_type) < 0)
                return nfserr_bad_xdr;
        if ((lockt->lt_type < NFS4_READ_LT) || (lockt->lt_type > NFS4_WRITEW_LT))
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lockt->lt_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lockt->lt_length) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_state_owner4(argp, &lockt->lt_clientid,
                                         &lockt->lt_owner);
}

static __be32
nfsd4_decode_locku(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_locku *locku = &u->locku;
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &locku->lu_type) < 0)
                return nfserr_bad_xdr;
        if ((locku->lu_type < NFS4_READ_LT) || (locku->lu_type > NFS4_WRITEW_LT))
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &locku->lu_seqid) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_stateid4(argp, &locku->lu_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &locku->lu_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &locku->lu_length) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_lookup(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_lookup *lookup = &u->lookup;
        return nfsd4_decode_component4(argp, &lookup->lo_name, &lookup->lo_len);
}

static __be32
nfsd4_decode_createhow4(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &open->op_createmode) < 0)
                return nfserr_bad_xdr;
        switch (open->op_createmode) {
        case NFS4_CREATE_UNCHECKED:
        case NFS4_CREATE_GUARDED:
                status = nfsd4_decode_fattr4(argp, open->op_bmval,
                                             ARRAY_SIZE(open->op_bmval),
                                             &open->op_iattr, &open->op_acl,
                                             &open->op_label, &open->op_umask,
                                             &open->op_dpacl, &open->op_pacl);
                if (status)
                        return status;
                break;
        case NFS4_CREATE_EXCLUSIVE:
                status = nfsd4_decode_verifier4(argp, &open->op_verf);
                if (status)
                        return status;
                break;
        case NFS4_CREATE_EXCLUSIVE4_1:
                if (argp->minorversion < 1)
                        return nfserr_bad_xdr;
                status = nfsd4_decode_verifier4(argp, &open->op_verf);
                if (status)
                        return status;
                status = nfsd4_decode_fattr4(argp, open->op_bmval,
                                             ARRAY_SIZE(open->op_bmval),
                                             &open->op_iattr, &open->op_acl,
                                             &open->op_label, &open->op_umask,
                                             &open->op_dpacl, &open->op_pacl);
                if (status)
                        return status;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_openflag4(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &open->op_create) < 0)
                return nfserr_bad_xdr;
        switch (open->op_create) {
        case NFS4_OPEN_NOCREATE:
                break;
        case NFS4_OPEN_CREATE:
                status = nfsd4_decode_createhow4(argp, open);
                if (status)
                        return status;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32 nfsd4_decode_share_access(struct nfsd4_compoundargs *argp, u32 *share_access, u32 *deleg_want, u32 *deleg_when)
{
        u32 w;

        if (xdr_stream_decode_u32(argp->xdr, &w) < 0)
                return nfserr_bad_xdr;
        *share_access = w & NFS4_SHARE_ACCESS_MASK;
        *deleg_want = w & NFS4_SHARE_WANT_MASK;
        if (deleg_when)
                *deleg_when = w & NFS4_SHARE_WHEN_MASK;

        switch (w & NFS4_SHARE_ACCESS_MASK) {
        case NFS4_SHARE_ACCESS_READ:
        case NFS4_SHARE_ACCESS_WRITE:
        case NFS4_SHARE_ACCESS_BOTH:
                break;
        default:
                return nfserr_bad_xdr;
        }
        w &= ~NFS4_SHARE_ACCESS_MASK;
        if (!w)
                return nfs_ok;
        if (!argp->minorversion)
                return nfserr_bad_xdr;
        switch (w & NFS4_SHARE_WANT_TYPE_MASK) {
        case OPEN4_SHARE_ACCESS_WANT_NO_PREFERENCE:
        case OPEN4_SHARE_ACCESS_WANT_READ_DELEG:
        case OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG:
        case OPEN4_SHARE_ACCESS_WANT_ANY_DELEG:
        case OPEN4_SHARE_ACCESS_WANT_NO_DELEG:
        case OPEN4_SHARE_ACCESS_WANT_CANCEL:
                break;
        default:
                return nfserr_bad_xdr;
        }
        w &= ~NFS4_SHARE_WANT_MASK;
        if (!w)
                return nfs_ok;

        if (!deleg_when)        /* open_downgrade */
                return nfserr_inval;
        switch (w) {
        case NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL:
        case NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED:
        case (NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL |
              NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED):
                return nfs_ok;
        }
        return nfserr_bad_xdr;
}

static __be32 nfsd4_decode_share_deny(struct nfsd4_compoundargs *argp, u32 *x)
{
        if (xdr_stream_decode_u32(argp->xdr, x) < 0)
                return nfserr_bad_xdr;
        /* Note: unlike access bits, deny bits may be zero. */
        if (*x & ~NFS4_SHARE_DENY_BOTH)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_open_claim4(struct nfsd4_compoundargs *argp,
                         struct nfsd4_open *open)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &open->op_claim_type) < 0)
                return nfserr_bad_xdr;
        switch (open->op_claim_type) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                status = nfsd4_decode_component4(argp, &open->op_fname,
                                                 &open->op_fnamelen);
                if (status)
                        return status;
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
                if (xdr_stream_decode_u32(argp->xdr, &open->op_delegate_type) < 0)
                        return nfserr_bad_xdr;
                break;
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
                status = nfsd4_decode_stateid4(argp, &open->op_delegate_stateid);
                if (status)
                        return status;
                status = nfsd4_decode_component4(argp, &open->op_fname,
                                                 &open->op_fnamelen);
                if (status)
                        return status;
                break;
        case NFS4_OPEN_CLAIM_FH:
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                if (argp->minorversion < 1)
                        return nfserr_bad_xdr;
                /* void */
                break;
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                if (argp->minorversion < 1)
                        return nfserr_bad_xdr;
                status = nfsd4_decode_stateid4(argp, &open->op_delegate_stateid);
                if (status)
                        return status;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_open(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_open *open = &u->open;
        __be32 status;
        u32 dummy;

        memset(open, 0, sizeof(*open));

        if (xdr_stream_decode_u32(argp->xdr, &open->op_seqid) < 0)
                return nfserr_bad_xdr;
        /* deleg_want is ignored */
        status = nfsd4_decode_share_access(argp, &open->op_share_access,
                                           &open->op_deleg_want, &dummy);
        if (status)
                return status;
        status = nfsd4_decode_share_deny(argp, &open->op_share_deny);
        if (status)
                return status;
        status = nfsd4_decode_state_owner4(argp, &open->op_clientid,
                                           &open->op_owner);
        if (status)
                return status;
        status = nfsd4_decode_openflag4(argp, open);
        if (status)
                return status;
        return nfsd4_decode_open_claim4(argp, open);
}

static __be32
nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp,
                          union nfsd4_op_u *u)
{
        struct nfsd4_open_confirm *open_conf = &u->open_confirm;
        __be32 status;

        if (argp->minorversion >= 1)
                return nfserr_notsupp;

        status = nfsd4_decode_stateid4(argp, &open_conf->oc_req_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &open_conf->oc_seqid) < 0)
                return nfserr_bad_xdr;

        memset(&open_conf->oc_resp_stateid, 0,
               sizeof(open_conf->oc_resp_stateid));
        return nfs_ok;
}

static __be32
nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp,
                            union nfsd4_op_u *u)
{
        struct nfsd4_open_downgrade *open_down = &u->open_downgrade;
        __be32 status;

        memset(open_down, 0, sizeof(*open_down));
        status = nfsd4_decode_stateid4(argp, &open_down->od_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &open_down->od_seqid) < 0)
                return nfserr_bad_xdr;
        /* deleg_want is ignored */
        status = nfsd4_decode_share_access(argp, &open_down->od_share_access,
                                           &open_down->od_deleg_want, NULL);
        if (status)
                return status;
        return nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
}

static __be32
nfsd4_decode_putfh(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_putfh *putfh = &u->putfh;
        __be32 *p;

        if (xdr_stream_decode_u32(argp->xdr, &putfh->pf_fhlen) < 0)
                return nfserr_bad_xdr;
        if (putfh->pf_fhlen > NFS4_FHSIZE)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, putfh->pf_fhlen);
        if (!p)
                return nfserr_bad_xdr;
        putfh->pf_fhval = svcxdr_savemem(argp, p, putfh->pf_fhlen);
        if (!putfh->pf_fhval)
                return nfserr_jukebox;

        putfh->no_verify = false;
        return nfs_ok;
}

static __be32
nfsd4_decode_read(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_read *read = &u->read;
        __be32 status;

        memset(read, 0, sizeof(*read));
        status = nfsd4_decode_stateid4(argp, &read->rd_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &read->rd_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &read->rd_length) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_readdir(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_readdir *readdir = &u->readdir;
        __be32 status;

        memset(readdir, 0, sizeof(*readdir));
        if (xdr_stream_decode_u64(argp->xdr, &readdir->rd_cookie) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_verifier4(argp, &readdir->rd_verf);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &readdir->rd_dircount) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &readdir->rd_maxcount) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_uint32_array(argp->xdr, readdir->rd_bmval,
                                           ARRAY_SIZE(readdir->rd_bmval)) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_remove(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_remove *remove = &u->remove;
        memset(&remove->rm_cinfo, 0, sizeof(remove->rm_cinfo));
        return nfsd4_decode_component4(argp, &remove->rm_name, &remove->rm_namelen);
}

static __be32
nfsd4_decode_rename(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_rename *rename = &u->rename;
        __be32 status;

        memset(rename, 0, sizeof(*rename));
        status = nfsd4_decode_component4(argp, &rename->rn_sname, &rename->rn_snamelen);
        if (status)
                return status;
        return nfsd4_decode_component4(argp, &rename->rn_tname, &rename->rn_tnamelen);
}

static __be32
nfsd4_decode_renew(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        clientid_t *clientid = &u->renew;
        return nfsd4_decode_clientid4(argp, clientid);
}

static __be32
nfsd4_decode_secinfo(struct nfsd4_compoundargs *argp,
                     union nfsd4_op_u *u)
{
        struct nfsd4_secinfo *secinfo = &u->secinfo;
        secinfo->si_exp = NULL;
        return nfsd4_decode_component4(argp, &secinfo->si_name, &secinfo->si_namelen);
}

static __be32
nfsd4_decode_setattr(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_setattr *setattr = &u->setattr;
        __be32 status;

        memset(setattr, 0, sizeof(*setattr));
        status = nfsd4_decode_stateid4(argp, &setattr->sa_stateid);
        if (status)
                return status;
        return nfsd4_decode_fattr4(argp, setattr->sa_bmval,
                                   ARRAY_SIZE(setattr->sa_bmval),
                                   &setattr->sa_iattr, &setattr->sa_acl,
                                   &setattr->sa_label, NULL, &setattr->sa_dpacl,
                                   &setattr->sa_pacl);
}

static __be32
nfsd4_decode_setclientid(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_setclientid *setclientid = &u->setclientid;
        __be32 *p, status;

        memset(setclientid, 0, sizeof(*setclientid));

        if (argp->minorversion >= 1)
                return nfserr_notsupp;

        status = nfsd4_decode_verifier4(argp, &setclientid->se_verf);
        if (status)
                return status;
        status = nfsd4_decode_opaque(argp, &setclientid->se_name);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_prog) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_netid_len) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, setclientid->se_callback_netid_len);
        if (!p)
                return nfserr_bad_xdr;
        setclientid->se_callback_netid_val = svcxdr_savemem(argp, p,
                                                setclientid->se_callback_netid_len);
        if (!setclientid->se_callback_netid_val)
                return nfserr_jukebox;

        if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_addr_len) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, setclientid->se_callback_addr_len);
        if (!p)
                return nfserr_bad_xdr;
        setclientid->se_callback_addr_val = svcxdr_savemem(argp, p,
                                                setclientid->se_callback_addr_len);
        if (!setclientid->se_callback_addr_val)
                return nfserr_jukebox;
        if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_ident) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_setclientid_confirm(struct nfsd4_compoundargs *argp,
                                 union nfsd4_op_u *u)
{
        struct nfsd4_setclientid_confirm *scd_c = &u->setclientid_confirm;
        __be32 status;

        if (argp->minorversion >= 1)
                return nfserr_notsupp;

        status = nfsd4_decode_clientid4(argp, &scd_c->sc_clientid);
        if (status)
                return status;
        return nfsd4_decode_verifier4(argp, &scd_c->sc_confirm);
}

/* Also used for NVERIFY */
static __be32
nfsd4_decode_verify(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_verify *verify = &u->verify;
        __be32 *p, status;

        memset(verify, 0, sizeof(*verify));

        status = nfsd4_decode_bitmap4(argp, verify->ve_bmval,
                                      ARRAY_SIZE(verify->ve_bmval));
        if (status)
                return status;

        /* For convenience's sake, we compare raw xdr'd attributes in
         * nfsd4_proc_verify */

        if (xdr_stream_decode_u32(argp->xdr, &verify->ve_attrlen) < 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, verify->ve_attrlen);
        if (!p)
                return nfserr_bad_xdr;
        verify->ve_attrval = svcxdr_savemem(argp, p, verify->ve_attrlen);
        if (!verify->ve_attrval)
                return nfserr_jukebox;

        return nfs_ok;
}

static __be32
nfsd4_decode_write(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_write *write = &u->write;
        __be32 status;

        status = nfsd4_decode_stateid4(argp, &write->wr_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &write->wr_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &write->wr_stable_how) < 0)
                return nfserr_bad_xdr;
        if (write->wr_stable_how > NFS_FILE_SYNC)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &write->wr_buflen) < 0)
                return nfserr_bad_xdr;
        if (!xdr_stream_subsegment(argp->xdr, &write->wr_payload, write->wr_buflen))
                return nfserr_bad_xdr;

        write->wr_bytes_written = 0;
        write->wr_how_written = 0;
        memset(&write->wr_verifier, 0, sizeof(write->wr_verifier));
        return nfs_ok;
}

static __be32
nfsd4_decode_release_lockowner(struct nfsd4_compoundargs *argp,
                               union nfsd4_op_u *u)
{
        struct nfsd4_release_lockowner *rlockowner = &u->release_lockowner;
        __be32 status;

        if (argp->minorversion >= 1)
                return nfserr_notsupp;

        status = nfsd4_decode_state_owner4(argp, &rlockowner->rl_clientid,
                                           &rlockowner->rl_owner);
        if (status)
                return status;

        if (argp->minorversion && !zero_clientid(&rlockowner->rl_clientid))
                return nfserr_inval;

        return nfs_ok;
}

static __be32 nfsd4_decode_backchannel_ctl(struct nfsd4_compoundargs *argp,
                                           union nfsd4_op_u *u)
{
        struct nfsd4_backchannel_ctl *bc = &u->backchannel_ctl;
        memset(bc, 0, sizeof(*bc));
        if (xdr_stream_decode_u32(argp->xdr, &bc->bc_cb_program) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_cb_sec(argp, &bc->bc_cb_sec);
}

static __be32 nfsd4_decode_bind_conn_to_session(struct nfsd4_compoundargs *argp,
                                                union nfsd4_op_u *u)
{
        struct nfsd4_bind_conn_to_session *bcts = &u->bind_conn_to_session;
        u32 use_conn_in_rdma_mode;
        __be32 status;

        memset(bcts, 0, sizeof(*bcts));
        status = nfsd4_decode_sessionid4(argp, &bcts->sessionid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &bcts->dir) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &use_conn_in_rdma_mode) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_state_protect_ops(struct nfsd4_compoundargs *argp,
                               struct nfsd4_exchange_id *exid)
{
        __be32 status;

        status = nfsd4_decode_bitmap4(argp, exid->spo_must_enforce,
                                      ARRAY_SIZE(exid->spo_must_enforce));
        if (status)
                return nfserr_bad_xdr;
        status = nfsd4_decode_bitmap4(argp, exid->spo_must_allow,
                                      ARRAY_SIZE(exid->spo_must_allow));
        if (status)
                return nfserr_bad_xdr;

        return nfs_ok;
}

/*
 * This implementation currently does not support SP4_SSV.
 * This decoder simply skips over these arguments.
 */
static noinline __be32
nfsd4_decode_ssv_sp_parms(struct nfsd4_compoundargs *argp,
                          struct nfsd4_exchange_id *exid)
{
        u32 count, window, num_gss_handles;
        __be32 status;

        /* ssp_ops */
        status = nfsd4_decode_state_protect_ops(argp, exid);
        if (status)
                return status;

        /* ssp_hash_algs<> */
        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;
        while (count--) {
                status = nfsd4_decode_ignored_string(argp, 0);
                if (status)
                        return status;
        }

        /* ssp_encr_algs<> */
        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;
        while (count--) {
                status = nfsd4_decode_ignored_string(argp, 0);
                if (status)
                        return status;
        }

        if (xdr_stream_decode_u32(argp->xdr, &window) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &num_gss_handles) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_state_protect4_a(struct nfsd4_compoundargs *argp,
                              struct nfsd4_exchange_id *exid)
{
        __be32 status;

        if (xdr_stream_decode_u32(argp->xdr, &exid->spa_how) < 0)
                return nfserr_bad_xdr;
        switch (exid->spa_how) {
        case SP4_NONE:
                break;
        case SP4_MACH_CRED:
                status = nfsd4_decode_state_protect_ops(argp, exid);
                if (status)
                        return status;
                break;
        case SP4_SSV:
                status = nfsd4_decode_ssv_sp_parms(argp, exid);
                if (status)
                        return status;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_nfs_impl_id4(struct nfsd4_compoundargs *argp,
                          struct nfsd4_exchange_id *exid)
{
        __be32 status;
        u32 count;

        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;
        switch (count) {
        case 0:
                break;
        case 1:
                /* Note that RFC 8881 places no length limit on
                 * nii_domain, but this implementation permits no
                 * more than NFS4_OPAQUE_LIMIT bytes */
                status = nfsd4_decode_opaque(argp, &exid->nii_domain);
                if (status)
                        return status;
                /* Note that RFC 8881 places no length limit on
                 * nii_name, but this implementation permits no
                 * more than NFS4_OPAQUE_LIMIT bytes */
                status = nfsd4_decode_opaque(argp, &exid->nii_name);
                if (status)
                        return status;
                status = nfsd4_decode_nfstime4(argp, &exid->nii_time);
                if (status)
                        return status;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
                         union nfsd4_op_u *u)
{
        struct nfsd4_exchange_id *exid = &u->exchange_id;
        __be32 status;

        memset(exid, 0, sizeof(*exid));
        status = nfsd4_decode_verifier4(argp, &exid->verifier);
        if (status)
                return status;
        status = nfsd4_decode_opaque(argp, &exid->clname);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &exid->flags) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_state_protect4_a(argp, exid);
        if (status)
                return status;
        return nfsd4_decode_nfs_impl_id4(argp, exid);
}

static __be32
nfsd4_decode_channel_attrs4(struct nfsd4_compoundargs *argp,
                            struct nfsd4_channel_attrs *ca)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, XDR_UNIT * 7);
        if (!p)
                return nfserr_bad_xdr;

        /* headerpadsz is ignored */
        p++;
        ca->maxreq_sz = be32_to_cpup(p++);
        ca->maxresp_sz = be32_to_cpup(p++);
        ca->maxresp_cached = be32_to_cpup(p++);
        ca->maxops = be32_to_cpup(p++);
        ca->maxreqs = be32_to_cpup(p++);
        ca->nr_rdma_attrs = be32_to_cpup(p);
        switch (ca->nr_rdma_attrs) {
        case 0:
                break;
        case 1:
                if (xdr_stream_decode_u32(argp->xdr, &ca->rdma_attrs) < 0)
                        return nfserr_bad_xdr;
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_create_session(struct nfsd4_compoundargs *argp,
                            union nfsd4_op_u *u)
{
        struct nfsd4_create_session *sess = &u->create_session;
        __be32 status;

        memset(sess, 0, sizeof(*sess));
        status = nfsd4_decode_clientid4(argp, &sess->clientid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &sess->seqid) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &sess->flags) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_channel_attrs4(argp, &sess->fore_channel);
        if (status)
                return status;
        status = nfsd4_decode_channel_attrs4(argp, &sess->back_channel);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &sess->callback_prog) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_cb_sec(argp, &sess->cb_sec);
}

static __be32
nfsd4_decode_destroy_session(struct nfsd4_compoundargs *argp,
                             union nfsd4_op_u *u)
{
        struct nfsd4_destroy_session *destroy_session = &u->destroy_session;
        return nfsd4_decode_sessionid4(argp, &destroy_session->sessionid);
}

static __be32
nfsd4_decode_free_stateid(struct nfsd4_compoundargs *argp,
                          union nfsd4_op_u *u)
{
        struct nfsd4_free_stateid *free_stateid = &u->free_stateid;
        return nfsd4_decode_stateid4(argp, &free_stateid->fr_stateid);
}

static __be32
nfsd4_decode_get_dir_delegation(struct nfsd4_compoundargs *argp,
                union nfsd4_op_u *u)
{
        struct nfsd4_get_dir_delegation *gdd = &u->get_dir_delegation;
        __be32 status;

        memset(gdd, 0, sizeof(*gdd));

        if (xdr_stream_decode_bool(argp->xdr, &gdd->gdda_signal_deleg_avail) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_bitmap4(argp, gdd->gdda_notification_types,
                                      ARRAY_SIZE(gdd->gdda_notification_types));
        if (status)
                return status;
        status = nfsd4_decode_nfstime4(argp, &gdd->gdda_child_attr_delay);
        if (status)
                return status;
        status = nfsd4_decode_nfstime4(argp, &gdd->gdda_dir_attr_delay);
        if (status)
                return status;
        status = nfsd4_decode_bitmap4(argp, gdd->gdda_child_attributes,
                                        ARRAY_SIZE(gdd->gdda_child_attributes));
        if (status)
                return status;
        return nfsd4_decode_bitmap4(argp, gdd->gdda_dir_attributes,
                                        ARRAY_SIZE(gdd->gdda_dir_attributes));
}

#ifdef CONFIG_NFSD_PNFS
static __be32
nfsd4_decode_getdeviceinfo(struct nfsd4_compoundargs *argp,
                union nfsd4_op_u *u)
{
        struct nfsd4_getdeviceinfo *gdev = &u->getdeviceinfo;
        __be32 status;

        memset(gdev, 0, sizeof(*gdev));
        status = nfsd4_decode_deviceid4(argp->xdr, &gdev->gd_devid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &gdev->gd_layout_type) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &gdev->gd_maxcount) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_uint32_array(argp->xdr,
                                           &gdev->gd_notify_types, 1) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_layoutcommit(struct nfsd4_compoundargs *argp,
                          union nfsd4_op_u *u)
{
        struct nfsd4_layoutcommit *lcp = &u->layoutcommit;
        __be32 *p, status;

        memset(lcp, 0, sizeof(*lcp));
        if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_seg.offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_seg.length) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_bool(argp->xdr, &lcp->lc_reclaim) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_stateid4(argp, &lcp->lc_sid);
        if (status)
                return status;
        if (xdr_stream_decode_bool(argp->xdr, &lcp->lc_newoffset) < 0)
                return nfserr_bad_xdr;
        if (lcp->lc_newoffset) {
                if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_last_wr) < 0)
                        return nfserr_bad_xdr;
        } else
                lcp->lc_last_wr = 0;
        p = xdr_inline_decode(argp->xdr, XDR_UNIT);
        if (!p)
                return nfserr_bad_xdr;
        if (xdr_item_is_present(p)) {
                status = nfsd4_decode_nfstime4(argp, &lcp->lc_mtime);
                if (status)
                        return status;
        } else {
                lcp->lc_mtime.tv_nsec = UTIME_NOW;
        }
        return nfsd4_decode_layoutupdate4(argp, lcp);
}

static __be32
nfsd4_decode_layoutget(struct nfsd4_compoundargs *argp,
                union nfsd4_op_u *u)
{
        struct nfsd4_layoutget *lgp = &u->layoutget;
        __be32 status;

        memset(lgp, 0, sizeof(*lgp));
        if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_signal) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_layout_type) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_seg.iomode) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_seg.offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_seg.length) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_minlength) < 0)
                return nfserr_bad_xdr;
        status = nfsd4_decode_stateid4(argp, &lgp->lg_sid);
        if (status)
                return status;
        if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_maxcount) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32
nfsd4_decode_layoutreturn(struct nfsd4_compoundargs *argp,
                union nfsd4_op_u *u)
{
        struct nfsd4_layoutreturn *lrp = &u->layoutreturn;
        memset(lrp, 0, sizeof(*lrp));
        if (xdr_stream_decode_bool(argp->xdr, &lrp->lr_reclaim) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_layout_type) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_seg.iomode) < 0)
                return nfserr_bad_xdr;
        return nfsd4_decode_layoutreturn4(argp, lrp);
}
#endif /* CONFIG_NFSD_PNFS */

static __be32 nfsd4_decode_secinfo_no_name(struct nfsd4_compoundargs *argp,
                                           union nfsd4_op_u *u)
{
        struct nfsd4_secinfo_no_name *sin = &u->secinfo_no_name;
        if (xdr_stream_decode_u32(argp->xdr, &sin->sin_style) < 0)
                return nfserr_bad_xdr;

        sin->sin_exp = NULL;
        return nfs_ok;
}

static __be32
nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
                      union nfsd4_op_u *u)
{
        struct nfsd4_sequence *seq = &u->sequence;
        __be32 *p, status;

        status = nfsd4_decode_sessionid4(argp, &seq->sessionid);
        if (status)
                return status;
        p = xdr_inline_decode(argp->xdr, XDR_UNIT * 4);
        if (!p)
                return nfserr_bad_xdr;
        seq->seqid = be32_to_cpup(p++);
        seq->slotid = be32_to_cpup(p++);
        /* sa_highest_slotid counts from 0 but maxslots  counts from 1 ... */
        seq->maxslots = be32_to_cpup(p++) + 1;
        seq->cachethis = be32_to_cpup(p);

        seq->status_flags = 0;
        return nfs_ok;
}

static __be32
nfsd4_decode_test_stateid(struct nfsd4_compoundargs *argp,
                          union nfsd4_op_u *u)
{
        struct nfsd4_test_stateid *test_stateid = &u->test_stateid;
        struct nfsd4_test_stateid_id *stateid;
        __be32 status;
        u32 i;

        memset(test_stateid, 0, sizeof(*test_stateid));
        if (xdr_stream_decode_u32(argp->xdr, &test_stateid->ts_num_ids) < 0)
                return nfserr_bad_xdr;

        INIT_LIST_HEAD(&test_stateid->ts_stateid_list);
        for (i = 0; i < test_stateid->ts_num_ids; i++) {
                stateid = svcxdr_tmpalloc(argp, sizeof(*stateid));
                if (!stateid)
                        return nfserr_jukebox;
                INIT_LIST_HEAD(&stateid->ts_id_list);
                list_add_tail(&stateid->ts_id_list, &test_stateid->ts_stateid_list);
                status = nfsd4_decode_stateid4(argp, &stateid->ts_id_stateid);
                if (status)
                        return status;
        }

        return nfs_ok;
}

static __be32 nfsd4_decode_destroy_clientid(struct nfsd4_compoundargs *argp,
                                            union nfsd4_op_u *u)
{
        struct nfsd4_destroy_clientid *dc = &u->destroy_clientid;
        return nfsd4_decode_clientid4(argp, &dc->clientid);
}

static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp,
                                            union nfsd4_op_u *u)
{
        struct nfsd4_reclaim_complete *rc = &u->reclaim_complete;
        if (xdr_stream_decode_bool(argp->xdr, &rc->rca_one_fs) < 0)
                return nfserr_bad_xdr;
        return nfs_ok;
}

static __be32
nfsd4_decode_fallocate(struct nfsd4_compoundargs *argp,
                       union nfsd4_op_u *u)
{
        struct nfsd4_fallocate *fallocate = &u->allocate;
        __be32 status;

        status = nfsd4_decode_stateid4(argp, &fallocate->falloc_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &fallocate->falloc_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &fallocate->falloc_length) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

static __be32 nfsd4_decode_nl4_server(struct nfsd4_compoundargs *argp,
                                      struct nl4_server *ns)
{
        struct nfs42_netaddr *naddr;
        __be32 *p;

        if (xdr_stream_decode_u32(argp->xdr, &ns->nl4_type) < 0)
                return nfserr_bad_xdr;

        /* currently support for 1 inter-server source server */
        switch (ns->nl4_type) {
        case NL4_NETADDR:
                naddr = &ns->u.nl4_addr;

                if (xdr_stream_decode_u32(argp->xdr, &naddr->netid_len) < 0)
                        return nfserr_bad_xdr;
                if (naddr->netid_len > RPCBIND_MAXNETIDLEN)
                        return nfserr_bad_xdr;

                p = xdr_inline_decode(argp->xdr, naddr->netid_len);
                if (!p)
                        return nfserr_bad_xdr;
                memcpy(naddr->netid, p, naddr->netid_len);

                if (xdr_stream_decode_u32(argp->xdr, &naddr->addr_len) < 0)
                        return nfserr_bad_xdr;
                if (naddr->addr_len > RPCBIND_MAXUADDRLEN)
                        return nfserr_bad_xdr;

                p = xdr_inline_decode(argp->xdr, naddr->addr_len);
                if (!p)
                        return nfserr_bad_xdr;
                memcpy(naddr->addr, p, naddr->addr_len);
                break;
        default:
                return nfserr_bad_xdr;
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_copy(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_copy *copy = &u->copy;
        u32 consecutive, i, count, sync;
        struct nl4_server *ns_dummy;
        __be32 status;

        memset(copy, 0, sizeof(*copy));
        status = nfsd4_decode_stateid4(argp, &copy->cp_src_stateid);
        if (status)
                return status;
        status = nfsd4_decode_stateid4(argp, &copy->cp_dst_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &copy->cp_src_pos) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &copy->cp_dst_pos) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &copy->cp_count) < 0)
                return nfserr_bad_xdr;
        /* ca_consecutive: we always do consecutive copies */
        if (xdr_stream_decode_u32(argp->xdr, &consecutive) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_bool(argp->xdr, &sync) < 0)
                return nfserr_bad_xdr;
        nfsd4_copy_set_sync(copy, sync);

        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;
        copy->cp_src = svcxdr_tmpalloc(argp, sizeof(*copy->cp_src));
        if (copy->cp_src == NULL)
                return nfserr_jukebox;
        if (count == 0) { /* intra-server copy */
                __set_bit(NFSD4_COPY_F_INTRA, &copy->cp_flags);
                return nfs_ok;
        }

        /* decode all the supplied server addresses but use only the first */
        status = nfsd4_decode_nl4_server(argp, copy->cp_src);
        if (status)
                return status;

        ns_dummy = kmalloc_obj(struct nl4_server);
        if (ns_dummy == NULL)
                return nfserr_jukebox;
        for (i = 0; i < count - 1; i++) {
                status = nfsd4_decode_nl4_server(argp, ns_dummy);
                if (status) {
                        kfree(ns_dummy);
                        return status;
                }
        }
        kfree(ns_dummy);

        return nfs_ok;
}

static __be32
nfsd4_decode_copy_notify(struct nfsd4_compoundargs *argp,
                         union nfsd4_op_u *u)
{
        struct nfsd4_copy_notify *cn = &u->copy_notify;
        __be32 status;

        memset(cn, 0, sizeof(*cn));
        cn->cpn_src = svcxdr_tmpalloc(argp, sizeof(*cn->cpn_src));
        if (cn->cpn_src == NULL)
                return nfserr_jukebox;
        cn->cpn_dst = svcxdr_tmpalloc(argp, sizeof(*cn->cpn_dst));
        if (cn->cpn_dst == NULL)
                return nfserr_jukebox;

        status = nfsd4_decode_stateid4(argp, &cn->cpn_src_stateid);
        if (status)
                return status;
        return nfsd4_decode_nl4_server(argp, cn->cpn_dst);
}

static __be32
nfsd4_decode_offload_status(struct nfsd4_compoundargs *argp,
                            union nfsd4_op_u *u)
{
        struct nfsd4_offload_status *os = &u->offload_status;
        os->count = 0;
        os->status = 0;
        return nfsd4_decode_stateid4(argp, &os->stateid);
}

static __be32
nfsd4_decode_seek(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_seek *seek = &u->seek;
        __be32 status;

        status = nfsd4_decode_stateid4(argp, &seek->seek_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &seek->seek_offset) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u32(argp->xdr, &seek->seek_whence) < 0)
                return nfserr_bad_xdr;

        seek->seek_eof = 0;
        seek->seek_pos = 0;
        return nfs_ok;
}

static __be32
nfsd4_decode_clone(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u)
{
        struct nfsd4_clone *clone = &u->clone;
        __be32 status;

        status = nfsd4_decode_stateid4(argp, &clone->cl_src_stateid);
        if (status)
                return status;
        status = nfsd4_decode_stateid4(argp, &clone->cl_dst_stateid);
        if (status)
                return status;
        if (xdr_stream_decode_u64(argp->xdr, &clone->cl_src_pos) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &clone->cl_dst_pos) < 0)
                return nfserr_bad_xdr;
        if (xdr_stream_decode_u64(argp->xdr, &clone->cl_count) < 0)
                return nfserr_bad_xdr;

        return nfs_ok;
}

/*
 * XDR data that is more than PAGE_SIZE in size is normally part of a
 * read or write. However, the size of extended attributes is limited
 * by the maximum request size, and then further limited by the underlying
 * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
 * is 64k). Since there is no kvec- or page-based interface to xattrs,
 * and we're not dealing with contiguous pages, we need to do some copying.
 */

/*
 * Decode data into buffer.
 */
static __be32
nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct xdr_buf *xdr,
                       char **bufp, size_t buflen)
{
        struct page **pages = xdr->pages;
        struct kvec *head = xdr->head;
        char *tmp, *dp;
        u32 len;

        if (buflen <= head->iov_len) {
                /*
                 * We're in luck, the head has enough space. Just return
                 * the head, no need for copying.
                 */
                *bufp = head->iov_base;
                return 0;
        }

        tmp = svcxdr_tmpalloc(argp, buflen);
        if (tmp == NULL)
                return nfserr_jukebox;

        dp = tmp;
        memcpy(dp, head->iov_base, head->iov_len);
        buflen -= head->iov_len;
        dp += head->iov_len;

        while (buflen > 0) {
                len = min_t(u32, buflen, PAGE_SIZE);
                memcpy(dp, page_address(*pages), len);

                buflen -= len;
                dp += len;
                pages++;
        }

        *bufp = tmp;
        return 0;
}

/*
 * Get a user extended attribute name from the XDR buffer.
 * It will not have the "user." prefix, so prepend it.
 * Lastly, check for nul characters in the name.
 */
static __be32
nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
{
        char *name, *sp, *dp;
        u32 namelen, cnt;
        __be32 *p;

        if (xdr_stream_decode_u32(argp->xdr, &namelen) < 0)
                return nfserr_bad_xdr;
        if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
                return nfserr_nametoolong;
        if (namelen == 0)
                return nfserr_bad_xdr;
        p = xdr_inline_decode(argp->xdr, namelen);
        if (!p)
                return nfserr_bad_xdr;
        name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
        if (!name)
                return nfserr_jukebox;
        memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);

        /*
         * Copy the extended attribute name over while checking for 0
         * characters.
         */
        sp = (char *)p;
        dp = name + XATTR_USER_PREFIX_LEN;
        cnt = namelen;

        while (cnt-- > 0) {
                if (*sp == '\0')
                        return nfserr_bad_xdr;
                *dp++ = *sp++;
        }
        *dp = '\0';

        *namep = name;

        return nfs_ok;
}

/*
 * A GETXATTR op request comes without a length specifier. We just set the
 * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
 * channel reply size. nfsd_getxattr will probe the length of the xattr,
 * check it against getxa_len, and allocate + return the value.
 */
static __be32
nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
                      union nfsd4_op_u *u)
{
        struct nfsd4_getxattr *getxattr = &u->getxattr;
        __be32 status;
        u32 maxcount;

        memset(getxattr, 0, sizeof(*getxattr));
        status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
        if (status)
                return status;

        maxcount = svc_max_payload(argp->rqstp);
        maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);

        getxattr->getxa_len = maxcount;
        return nfs_ok;
}

static __be32
nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
                      union nfsd4_op_u *u)
{
        struct nfsd4_setxattr *setxattr = &u->setxattr;
        u32 flags, maxcount, size;
        __be32 status;

        memset(setxattr, 0, sizeof(*setxattr));

        if (xdr_stream_decode_u32(argp->xdr, &flags) < 0)
                return nfserr_bad_xdr;

        if (flags > SETXATTR4_REPLACE)
                return nfserr_inval;
        setxattr->setxa_flags = flags;

        status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
        if (status)
                return status;

        maxcount = svc_max_payload(argp->rqstp);
        maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);

        if (xdr_stream_decode_u32(argp->xdr, &size) < 0)
                return nfserr_bad_xdr;
        if (size > maxcount)
                return nfserr_xattr2big;

        setxattr->setxa_len = size;
        if (size > 0) {
                struct xdr_buf payload;

                if (!xdr_stream_subsegment(argp->xdr, &payload, size))
                        return nfserr_bad_xdr;
                status = nfsd4_vbuf_from_vector(argp, &payload,
                                                &setxattr->setxa_buf, size);
        }

        return nfs_ok;
}

static __be32
nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
                        union nfsd4_op_u *u)
{
        struct nfsd4_listxattrs *listxattrs = &u->listxattrs;
        u32 maxcount;

        memset(listxattrs, 0, sizeof(*listxattrs));

        if (xdr_stream_decode_u64(argp->xdr, &listxattrs->lsxa_cookie) < 0)
                return nfserr_bad_xdr;

        /*
         * If the cookie  is too large to have even one user.x attribute
         * plus trailing '\0' left in a maximum size buffer, it's invalid.
         */
        if (listxattrs->lsxa_cookie >=
            (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
                return nfserr_badcookie;

        if (xdr_stream_decode_u32(argp->xdr, &maxcount) < 0)
                return nfserr_bad_xdr;
        if (maxcount < 8)
                /* Always need at least 2 words (length and one character) */
                return nfserr_inval;

        maxcount = min(maxcount, svc_max_payload(argp->rqstp));
        listxattrs->lsxa_maxcount = maxcount;

        return nfs_ok;
}

static __be32
nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
                         union nfsd4_op_u *u)
{
        struct nfsd4_removexattr *removexattr = &u->removexattr;
        memset(removexattr, 0, sizeof(*removexattr));
        return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
}

static __be32
nfsd4_decode_noop(struct nfsd4_compoundargs *argp, union nfsd4_op_u *p)
{
        return nfs_ok;
}

static __be32
nfsd4_decode_notsupp(struct nfsd4_compoundargs *argp, union nfsd4_op_u *p)
{
        return nfserr_notsupp;
}

typedef __be32(*nfsd4_dec)(struct nfsd4_compoundargs *argp, union nfsd4_op_u *u);

static const nfsd4_dec nfsd4_dec_ops[] = {
        [OP_ACCESS]             = nfsd4_decode_access,
        [OP_CLOSE]              = nfsd4_decode_close,
        [OP_COMMIT]             = nfsd4_decode_commit,
        [OP_CREATE]             = nfsd4_decode_create,
        [OP_DELEGPURGE]         = nfsd4_decode_notsupp,
        [OP_DELEGRETURN]        = nfsd4_decode_delegreturn,
        [OP_GETATTR]            = nfsd4_decode_getattr,
        [OP_GETFH]              = nfsd4_decode_noop,
        [OP_LINK]               = nfsd4_decode_link,
        [OP_LOCK]               = nfsd4_decode_lock,
        [OP_LOCKT]              = nfsd4_decode_lockt,
        [OP_LOCKU]              = nfsd4_decode_locku,
        [OP_LOOKUP]             = nfsd4_decode_lookup,
        [OP_LOOKUPP]            = nfsd4_decode_noop,
        [OP_NVERIFY]            = nfsd4_decode_verify,
        [OP_OPEN]               = nfsd4_decode_open,
        [OP_OPENATTR]           = nfsd4_decode_notsupp,
        [OP_OPEN_CONFIRM]       = nfsd4_decode_open_confirm,
        [OP_OPEN_DOWNGRADE]     = nfsd4_decode_open_downgrade,
        [OP_PUTFH]              = nfsd4_decode_putfh,
        [OP_PUTPUBFH]           = nfsd4_decode_noop,
        [OP_PUTROOTFH]          = nfsd4_decode_noop,
        [OP_READ]               = nfsd4_decode_read,
        [OP_READDIR]            = nfsd4_decode_readdir,
        [OP_READLINK]           = nfsd4_decode_noop,
        [OP_REMOVE]             = nfsd4_decode_remove,
        [OP_RENAME]             = nfsd4_decode_rename,
        [OP_RENEW]              = nfsd4_decode_renew,
        [OP_RESTOREFH]          = nfsd4_decode_noop,
        [OP_SAVEFH]             = nfsd4_decode_noop,
        [OP_SECINFO]            = nfsd4_decode_secinfo,
        [OP_SETATTR]            = nfsd4_decode_setattr,
        [OP_SETCLIENTID]        = nfsd4_decode_setclientid,
        [OP_SETCLIENTID_CONFIRM] = nfsd4_decode_setclientid_confirm,
        [OP_VERIFY]             = nfsd4_decode_verify,
        [OP_WRITE]              = nfsd4_decode_write,
        [OP_RELEASE_LOCKOWNER]  = nfsd4_decode_release_lockowner,

        /* new operations for NFSv4.1 */
        [OP_BACKCHANNEL_CTL]    = nfsd4_decode_backchannel_ctl,
        [OP_BIND_CONN_TO_SESSION] = nfsd4_decode_bind_conn_to_session,
        [OP_EXCHANGE_ID]        = nfsd4_decode_exchange_id,
        [OP_CREATE_SESSION]     = nfsd4_decode_create_session,
        [OP_DESTROY_SESSION]    = nfsd4_decode_destroy_session,
        [OP_FREE_STATEID]       = nfsd4_decode_free_stateid,
        [OP_GET_DIR_DELEGATION] = nfsd4_decode_get_dir_delegation,
#ifdef CONFIG_NFSD_PNFS
        [OP_GETDEVICEINFO]      = nfsd4_decode_getdeviceinfo,
        [OP_GETDEVICELIST]      = nfsd4_decode_notsupp,
        [OP_LAYOUTCOMMIT]       = nfsd4_decode_layoutcommit,
        [OP_LAYOUTGET]          = nfsd4_decode_layoutget,
        [OP_LAYOUTRETURN]       = nfsd4_decode_layoutreturn,
#else
        [OP_GETDEVICEINFO]      = nfsd4_decode_notsupp,
        [OP_GETDEVICELIST]      = nfsd4_decode_notsupp,
        [OP_LAYOUTCOMMIT]       = nfsd4_decode_notsupp,
        [OP_LAYOUTGET]          = nfsd4_decode_notsupp,
        [OP_LAYOUTRETURN]       = nfsd4_decode_notsupp,
#endif
        [OP_SECINFO_NO_NAME]    = nfsd4_decode_secinfo_no_name,
        [OP_SEQUENCE]           = nfsd4_decode_sequence,
        [OP_SET_SSV]            = nfsd4_decode_notsupp,
        [OP_TEST_STATEID]       = nfsd4_decode_test_stateid,
        [OP_WANT_DELEGATION]    = nfsd4_decode_notsupp,
        [OP_DESTROY_CLIENTID]   = nfsd4_decode_destroy_clientid,
        [OP_RECLAIM_COMPLETE]   = nfsd4_decode_reclaim_complete,

        /* new operations for NFSv4.2 */
        [OP_ALLOCATE]           = nfsd4_decode_fallocate,
        [OP_COPY]               = nfsd4_decode_copy,
        [OP_COPY_NOTIFY]        = nfsd4_decode_copy_notify,
        [OP_DEALLOCATE]         = nfsd4_decode_fallocate,
        [OP_IO_ADVISE]          = nfsd4_decode_notsupp,
        [OP_LAYOUTERROR]        = nfsd4_decode_notsupp,
        [OP_LAYOUTSTATS]        = nfsd4_decode_notsupp,
        [OP_OFFLOAD_CANCEL]     = nfsd4_decode_offload_status,
        [OP_OFFLOAD_STATUS]     = nfsd4_decode_offload_status,
        [OP_READ_PLUS]          = nfsd4_decode_read,
        [OP_SEEK]               = nfsd4_decode_seek,
        [OP_WRITE_SAME]         = nfsd4_decode_notsupp,
        [OP_CLONE]              = nfsd4_decode_clone,
        /* RFC 8276 extended atributes operations */
        [OP_GETXATTR]           = nfsd4_decode_getxattr,
        [OP_SETXATTR]           = nfsd4_decode_setxattr,
        [OP_LISTXATTRS]         = nfsd4_decode_listxattrs,
        [OP_REMOVEXATTR]        = nfsd4_decode_removexattr,
};

static inline bool
nfsd4_opnum_in_range(struct nfsd4_compoundargs *argp, struct nfsd4_op *op)
{
        if (op->opnum < FIRST_NFS4_OP)
                return false;
        else if (argp->minorversion == 0 && op->opnum > LAST_NFS40_OP)
                return false;
        else if (argp->minorversion == 1 && op->opnum > LAST_NFS41_OP)
                return false;
        else if (argp->minorversion == 2 && op->opnum > LAST_NFS42_OP)
                return false;
        return true;
}

static bool
nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
{
        struct nfsd4_op *op;
        bool cachethis = false;
        int auth_slack= argp->rqstp->rq_auth_slack;
        int max_reply = auth_slack + 8; /* opcnt, status */
        int readcount = 0;
        int readbytes = 0;
        __be32 *p;
        int i;

        if (xdr_stream_decode_u32(argp->xdr, &argp->taglen) < 0)
                return false;
        max_reply += XDR_UNIT;
        argp->tag = NULL;
        if (unlikely(argp->taglen)) {
                if (argp->taglen > NFSD4_MAX_TAGLEN)
                        return false;
                p = xdr_inline_decode(argp->xdr, argp->taglen);
                if (!p)
                        return false;
                argp->tag = svcxdr_savemem(argp, p, argp->taglen);
                if (!argp->tag)
                        return false;
                max_reply += xdr_align_size(argp->taglen);
        }

        if (xdr_stream_decode_u32(argp->xdr, &argp->minorversion) < 0)
                return false;
        if (xdr_stream_decode_u32(argp->xdr, &argp->client_opcnt) < 0)
                return false;
        argp->opcnt = min_t(u32, argp->client_opcnt,
                            NFSD_MAX_OPS_PER_COMPOUND);

        if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
                argp->ops = vcalloc(argp->opcnt, sizeof(*argp->ops));
                if (!argp->ops) {
                        argp->ops = argp->iops;
                        return false;
                }
        }

        if (argp->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
                argp->opcnt = 0;

        for (i = 0; i < argp->opcnt; i++) {
                op = &argp->ops[i];
                op->replay = NULL;
                op->opdesc = NULL;

                if (xdr_stream_decode_u32(argp->xdr, &op->opnum) < 0)
                        return false;
                if (nfsd4_opnum_in_range(argp, op)) {
                        op->opdesc = OPDESC(op);
                        op->status = nfsd4_dec_ops[op->opnum](argp, &op->u);
                        if (op->status != nfs_ok)
                                trace_nfsd_compound_decode_err(argp->rqstp,
                                                               argp->opcnt, i,
                                                               op->opnum,
                                                               op->status);
                } else {
                        op->opnum = OP_ILLEGAL;
                        op->status = nfserr_op_illegal;
                }

                /*
                 * We'll try to cache the result in the DRC if any one
                 * op in the compound wants to be cached:
                 */
                cachethis |= nfsd4_cache_this_op(op);

                if (op->opnum == OP_READ || op->opnum == OP_READ_PLUS) {
                        readcount++;
                        readbytes += nfsd4_max_reply(argp->rqstp, op);
                } else
                        max_reply += nfsd4_max_reply(argp->rqstp, op);
                /*
                 * OP_LOCK and OP_LOCKT may return a conflicting lock.
                 * (Special case because it will just skip encoding this
                 * if it runs out of xdr buffer space, and it is the only
                 * operation that behaves this way.)
                 */
                if (op->opnum == OP_LOCK || op->opnum == OP_LOCKT)
                        max_reply += NFS4_OPAQUE_LIMIT;

                if (op->status) {
                        argp->opcnt = i+1;
                        break;
                }
        }
        /* Sessions make the DRC unnecessary: */
        if (argp->minorversion)
                cachethis = false;
        svc_reserve_auth(argp->rqstp, max_reply + readbytes);
        argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE;

        argp->splice_ok = nfsd_read_splice_ok(argp->rqstp);
        if (readcount > 1 || max_reply > PAGE_SIZE - auth_slack)
                argp->splice_ok = false;

        return true;
}

static __be32 nfsd4_encode_nfs_fh4(struct xdr_stream *xdr,
                                   struct knfsd_fh *fh_handle)
{
        return nfsd4_encode_opaque(xdr, fh_handle->fh_raw, fh_handle->fh_size);
}

/* This is a frequently-encoded type; open-coded for speed */
static __be32 nfsd4_encode_nfstime4(struct xdr_stream *xdr,
                                    const struct timespec64 *tv)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 3);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_hyper(p, tv->tv_sec);
        *p = cpu_to_be32(tv->tv_nsec);
        return nfs_ok;
}

static __be32 nfsd4_encode_specdata4(struct xdr_stream *xdr,
                                     unsigned int major, unsigned int minor)
{
        __be32 status;

        status = nfsd4_encode_uint32_t(xdr, major);
        if (status != nfs_ok)
                return status;
        return nfsd4_encode_uint32_t(xdr, minor);
}

static __be32
nfsd4_encode_change_info4(struct xdr_stream *xdr, const struct nfsd4_change_info *c)
{
        __be32 status;

        status = nfsd4_encode_bool(xdr, c->atomic);
        if (status != nfs_ok)
                return status;
        status = nfsd4_encode_changeid4(xdr, c->before_change);
        if (status != nfs_ok)
                return status;
        return nfsd4_encode_changeid4(xdr, c->after_change);
}

static __be32 nfsd4_encode_netaddr4(struct xdr_stream *xdr,
                                    const struct nfs42_netaddr *addr)
{
        __be32 status;

        /* na_r_netid */
        status = nfsd4_encode_opaque(xdr, addr->netid, addr->netid_len);
        if (status != nfs_ok)
                return status;
        /* na_r_addr */
        return nfsd4_encode_opaque(xdr, addr->addr, addr->addr_len);
}

/* Encode as an array of strings the string given with components
 * separated @sep, escaped with esc_enter and esc_exit.
 */
static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
                                          char *components, char esc_enter,
                                          char esc_exit)
{
        __be32 *p;
        __be32 pathlen;
        int pathlen_offset;
        char *str, *end, *next;
        int count = 0;

        pathlen_offset = xdr->buf->len;
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        p++; /* We will fill this in with @count later */

        end = str = components;
        while (*end) {
                bool found_esc = false;

                /* try to parse as esc_start, ..., esc_end, sep */
                if (*str == esc_enter) {
                        for (; *end && (*end != esc_exit); end++)
                                /* find esc_exit or end of string */;
                        next = end + 1;
                        if (*end && (!*next || *next == sep)) {
                                str++;
                                found_esc = true;
                        }
                }

                if (!found_esc)
                        for (; *end && (*end != sep); end++)
                                /* find sep or end of string */;

                if (end > str) {
                        if (xdr_stream_encode_opaque(xdr, str, end - str) < 0)
                                return nfserr_resource;
                        count++;
                } else
                        end++;
                if (found_esc)
                        end = next;

                str = end;
        }
        pathlen = htonl(count);
        write_bytes_to_xdr_buf(xdr->buf, pathlen_offset, &pathlen, 4);
        return 0;
}

/* Encode as an array of strings the string given with components
 * separated @sep.
 */
static __be32 nfsd4_encode_components(struct xdr_stream *xdr, char sep,
                                      char *components)
{
        return nfsd4_encode_components_esc(xdr, sep, components, 0, 0);
}

static __be32 nfsd4_encode_fs_location4(struct xdr_stream *xdr,
                                        struct nfsd4_fs_location *location)
{
        __be32 status;

        status = nfsd4_encode_components_esc(xdr, ':', location->hosts,
                                                '[', ']');
        if (status)
                return status;
        status = nfsd4_encode_components(xdr, '/', location->path);
        if (status)
                return status;
        return nfs_ok;
}

static __be32 nfsd4_encode_pathname4(struct xdr_stream *xdr,
                                     const struct path *root,
                                     const struct path *path)
{
        struct path cur = *path;
        struct dentry **components = NULL;
        unsigned int ncomponents = 0;
        __be32 err = nfserr_jukebox;

        dprintk("nfsd4_encode_components(");

        path_get(&cur);
        /* First walk the path up to the nfsd root, and store the
         * dentries/path components in an array.
         */
        for (;;) {
                if (path_equal(&cur, root))
                        break;
                if (cur.dentry == cur.mnt->mnt_root) {
                        if (follow_up(&cur))
                                continue;
                        goto out_free;
                }
                if ((ncomponents & 15) == 0) {
                        struct dentry **new;
                        new = krealloc(components,
                                        sizeof(*new) * (ncomponents + 16),
                                        GFP_KERNEL);
                        if (!new)
                                goto out_free;
                        components = new;
                }
                components[ncomponents++] = cur.dentry;
                cur.dentry = dget_parent(cur.dentry);
        }

        err = nfserr_resource;
        if (xdr_stream_encode_u32(xdr, ncomponents) != XDR_UNIT)
                goto out_free;
        while (ncomponents) {
                struct dentry *dentry = components[ncomponents - 1];

                spin_lock(&dentry->d_lock);
                if (xdr_stream_encode_opaque(xdr, dentry->d_name.name,
                                             dentry->d_name.len) < 0) {
                        spin_unlock(&dentry->d_lock);
                        goto out_free;
                }
                dprintk("/%pd", dentry);
                spin_unlock(&dentry->d_lock);
                dput(dentry);
                ncomponents--;
        }

        err = 0;
out_free:
        dprintk(")\n");
        while (ncomponents)
                dput(components[--ncomponents]);
        kfree(components);
        path_put(&cur);
        return err;
}

static __be32 nfsd4_encode_fs_locations4(struct xdr_stream *xdr,
                                         struct svc_rqst *rqstp,
                                         struct svc_export *exp)
{
        struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;
        struct svc_export *exp_ps;
        unsigned int i;
        __be32 status;

        /* fs_root */
        exp_ps = rqst_find_fsidzero_export(rqstp);
        if (IS_ERR(exp_ps))
                return nfserrno(PTR_ERR(exp_ps));
        status = nfsd4_encode_pathname4(xdr, &exp_ps->ex_path, &exp->ex_path);
        exp_put(exp_ps);
        if (status != nfs_ok)
                return status;

        /* locations<> */
        if (xdr_stream_encode_u32(xdr, fslocs->locations_count) != XDR_UNIT)
                return nfserr_resource;
        for (i = 0; i < fslocs->locations_count; i++) {
                status = nfsd4_encode_fs_location4(xdr, &fslocs->locations[i]);
                if (status != nfs_ok)
                        return status;
        }

        return nfs_ok;
}

static __be32 nfsd4_encode_nfsace4(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                                   struct nfs4_ace *ace)
{
        __be32 status;

        /* type */
        status = nfsd4_encode_acetype4(xdr, ace->type);
        if (status != nfs_ok)
                return nfserr_resource;
        /* flag */
        status = nfsd4_encode_aceflag4(xdr, ace->flag);
        if (status != nfs_ok)
                return nfserr_resource;
        /* access mask */
        status = nfsd4_encode_acemask4(xdr, ace->access_mask & NFS4_ACE_MASK_ALL);
        if (status != nfs_ok)
                return nfserr_resource;
        /* who */
        if (ace->whotype != NFS4_ACL_WHO_NAMED)
                return nfs4_acl_write_who(xdr, ace->whotype);
        if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                return nfsd4_encode_group(xdr, rqstp, ace->who_gid);
        return nfsd4_encode_user(xdr, rqstp, ace->who_uid);
}

#define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
                              FATTR4_WORD0_RDATTR_ERROR)
#define WORD1_ABSENT_FS_ATTRS FATTR4_WORD1_MOUNTED_ON_FILEID
#define WORD2_ABSENT_FS_ATTRS 0

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
static inline __be32
nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                            const struct lsm_context *context)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
        if (!p)
                return nfserr_resource;

        /*
         * For now we use a 0 here to indicate the null translation; in
         * the future we may place a call to translation code here.
         */
        *p++ = cpu_to_be32(0); /* lfs */
        *p++ = cpu_to_be32(0); /* pi */
        p = xdr_encode_opaque(p, context->context, context->len);
        return 0;
}
#else
static inline __be32
nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                            struct lsm_context *context)
{ return 0; }
#endif

#ifdef CONFIG_NFSD_V4_POSIX_ACLS

static int nfsd4_posix_tagtotype(short tag)
{
        switch (tag) {
        case ACL_USER_OBJ:      return POSIXACE4_TAG_USER_OBJ;
        case ACL_GROUP_OBJ:     return POSIXACE4_TAG_GROUP_OBJ;
        case ACL_USER:          return POSIXACE4_TAG_USER;
        case ACL_GROUP:         return POSIXACE4_TAG_GROUP;
        case ACL_MASK:          return POSIXACE4_TAG_MASK;
        case ACL_OTHER:         return POSIXACE4_TAG_OTHER;
        default:                return -EINVAL;
        }
}

static __be32
nfsd4_encode_posixace4(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                       struct posix_acl_entry *acep)
{
        __be32 status;
        int type;

        type = nfsd4_posix_tagtotype(acep->e_tag);
        if (type < 0)
                return nfserr_resource;
        if (!xdrgen_encode_posixacetag4(xdr, type))
                return nfserr_resource;
        if (!xdrgen_encode_posixaceperm4(xdr, acep->e_perm))
                return nfserr_resource;

        /* who */
        switch (acep->e_tag) {
        case ACL_USER_OBJ:
        case ACL_GROUP_OBJ:
        case ACL_MASK:
        case ACL_OTHER:
                if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                        return nfserr_resource;
                break;
        case ACL_USER:
                status = nfsd4_encode_user(xdr, rqstp, acep->e_uid);
                if (status != nfs_ok)
                        return status;
                break;
        case ACL_GROUP:
                status = nfsd4_encode_group(xdr, rqstp, acep->e_gid);
                if (status != nfs_ok)
                        return status;
                break;
        default:
                return nfserr_resource;
        }
        return nfs_ok;
}

static __be32
nfsd4_encode_posixacl(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                      struct posix_acl *acl)
{
        __be32 status;
        int i;

        if (!acl) {
                if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                        return nfserr_resource;
                return nfs_ok;
        }

        if (acl->a_count > NFS_ACL_MAX_ENTRIES)
                return nfserr_resource;
        if (xdr_stream_encode_u32(xdr, acl->a_count) != XDR_UNIT)
                return nfserr_resource;
        for (i = 0; i < acl->a_count; i++) {
                status = nfsd4_encode_posixace4(xdr, rqstp, &acl->a_entries[i]);
                if (status != nfs_ok)
                        return status;
        }

        return nfs_ok;
}

#endif /* CONFIG_NFSD_V4_POSIX_ACL */

static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *bmval2, u32 *rdattr_err)
{
        /* As per referral draft:  */
        if (*bmval0 & ~WORD0_ABSENT_FS_ATTRS ||
            *bmval1 & ~WORD1_ABSENT_FS_ATTRS) {
                if (*bmval0 & FATTR4_WORD0_RDATTR_ERROR ||
                    *bmval0 & FATTR4_WORD0_FS_LOCATIONS)
                        *rdattr_err = NFSERR_MOVED;
                else
                        return nfserr_moved;
        }
        *bmval0 &= WORD0_ABSENT_FS_ATTRS;
        *bmval1 &= WORD1_ABSENT_FS_ATTRS;
        *bmval2 &= WORD2_ABSENT_FS_ATTRS;
        return 0;
}


static int nfsd4_get_mounted_on_ino(struct svc_export *exp, u64 *pino)
{
        struct path path = exp->ex_path;
        struct kstat stat;
        int err;

        path_get(&path);
        while (follow_up(&path)) {
                if (path.dentry != path.mnt->mnt_root)
                        break;
        }
        err = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT);
        path_put(&path);
        if (!err)
                *pino = stat.ino;
        return err;
}

static __be32
nfsd4_encode_bitmap4(struct xdr_stream *xdr, u32 bmval0, u32 bmval1, u32 bmval2)
{
        __be32 *p;

        if (bmval2) {
                p = xdr_reserve_space(xdr, XDR_UNIT * 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(3);
                *p++ = cpu_to_be32(bmval0);
                *p++ = cpu_to_be32(bmval1);
                *p++ = cpu_to_be32(bmval2);
        } else if (bmval1) {
                p = xdr_reserve_space(xdr, XDR_UNIT * 3);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(2);
                *p++ = cpu_to_be32(bmval0);
                *p++ = cpu_to_be32(bmval1);
        } else {
                p = xdr_reserve_space(xdr, XDR_UNIT * 2);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
                *p++ = cpu_to_be32(bmval0);
        }

        return nfs_ok;
out_resource:
        return nfserr_resource;
}

struct nfsd4_fattr_args {
        struct svc_rqst         *rqstp;
        struct svc_fh           *fhp;
        struct svc_export       *exp;
        struct dentry           *dentry;
        struct kstat            stat;
        struct kstatfs          statfs;
        struct nfs4_acl         *acl;
        u64                     change_attr;
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        struct lsm_context      context;
#endif
#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        struct posix_acl        *dpacl;
        struct posix_acl        *pacl;
#endif
        u32                     rdattr_err;
        bool                    contextsupport;
        bool                    ignore_crossmnt;
};

typedef __be32(*nfsd4_enc_attr)(struct xdr_stream *xdr,
                                const struct nfsd4_fattr_args *args);

static __be32 nfsd4_encode_fattr4__inval(struct xdr_stream *xdr,
                                         const struct nfsd4_fattr_args *args)
{
        return nfserr_inval;
}

static __be32 nfsd4_encode_fattr4__noop(struct xdr_stream *xdr,
                                        const struct nfsd4_fattr_args *args)
{
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4__true(struct xdr_stream *xdr,
                                        const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_bool(xdr, true);
}

static __be32 nfsd4_encode_fattr4__false(struct xdr_stream *xdr,
                                         const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_bool(xdr, false);
}

static __be32 nfsd4_encode_fattr4_supported_attrs(struct xdr_stream *xdr,
                                                  const struct nfsd4_fattr_args *args)
{
        struct nfsd4_compoundres *resp = args->rqstp->rq_resp;
        u32 minorversion = resp->cstate.minorversion;
        u32 supp[3];

        memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));
        if (!IS_POSIXACL(d_inode(args->dentry)))
                supp[0] &= ~FATTR4_WORD0_ACL;
        if (!args->contextsupport)
                supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;

        return nfsd4_encode_bitmap4(xdr, supp[0], supp[1], supp[2]);
}

static __be32 nfsd4_encode_fattr4_type(struct xdr_stream *xdr,
                                       const struct nfsd4_fattr_args *args)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT);
        if (!p)
                return nfserr_resource;

        switch (args->stat.mode & S_IFMT) {
        case S_IFIFO:
                *p = cpu_to_be32(NF4FIFO);
                break;
        case S_IFCHR:
                *p = cpu_to_be32(NF4CHR);
                break;
        case S_IFDIR:
                *p = cpu_to_be32(NF4DIR);
                break;
        case S_IFBLK:
                *p = cpu_to_be32(NF4BLK);
                break;
        case S_IFLNK:
                *p = cpu_to_be32(NF4LNK);
                break;
        case S_IFREG:
                *p = cpu_to_be32(NF4REG);
                break;
        case S_IFSOCK:
                *p = cpu_to_be32(NF4SOCK);
                break;
        default:
                return nfserr_serverfault;
        }

        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_fh_expire_type(struct xdr_stream *xdr,
                                                 const struct nfsd4_fattr_args *args)
{
        u32 mask;

        mask = NFS4_FH_PERSISTENT;
        if (!(args->exp->ex_flags & NFSEXP_NOSUBTREECHECK))
                mask |= NFS4_FH_VOL_RENAME;
        return nfsd4_encode_uint32_t(xdr, mask);
}

static __be32 nfsd4_encode_fattr4_change(struct xdr_stream *xdr,
                                         const struct nfsd4_fattr_args *args)
{
        const struct svc_export *exp = args->exp;

        if (unlikely(exp->ex_flags & NFSEXP_V4ROOT)) {
                u32 flush_time = convert_to_wallclock(exp->cd->flush_time);

                if (xdr_stream_encode_u32(xdr, flush_time) != XDR_UNIT)
                        return nfserr_resource;
                if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                        return nfserr_resource;
                return nfs_ok;
        }
        return nfsd4_encode_changeid4(xdr, args->change_attr);
}

static __be32 nfsd4_encode_fattr4_size(struct xdr_stream *xdr,
                                       const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, args->stat.size);
}

static __be32 nfsd4_encode_fattr4_fsid(struct xdr_stream *xdr,
                                       const struct nfsd4_fattr_args *args)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 2 + XDR_UNIT * 2);
        if (!p)
                return nfserr_resource;

        if (unlikely(args->exp->ex_fslocs.migrated)) {
                p = xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MAJOR);
                xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MINOR);
                return nfs_ok;
        }
        switch (fsid_source(args->fhp)) {
        case FSIDSOURCE_FSID:
                p = xdr_encode_hyper(p, (u64)args->exp->ex_fsid);
                xdr_encode_hyper(p, (u64)0);
                break;
        case FSIDSOURCE_DEV:
                *p++ = xdr_zero;
                *p++ = cpu_to_be32(MAJOR(args->stat.dev));
                *p++ = xdr_zero;
                *p   = cpu_to_be32(MINOR(args->stat.dev));
                break;
        case FSIDSOURCE_UUID:
                xdr_encode_opaque_fixed(p, args->exp->ex_uuid, EX_UUID_LEN);
                break;
        }

        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_lease_time(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        struct nfsd_net *nn = net_generic(SVC_NET(args->rqstp), nfsd_net_id);

        return nfsd4_encode_nfs_lease4(xdr, nn->nfsd4_lease);
}

static __be32 nfsd4_encode_fattr4_rdattr_error(struct xdr_stream *xdr,
                                               const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint32_t(xdr, args->rdattr_err);
}

static __be32 nfsd4_encode_fattr4_aclsupport(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        u32 mask;

        mask = 0;
        if (IS_POSIXACL(d_inode(args->dentry)))
                mask = ACL4_SUPPORT_ALLOW_ACL | ACL4_SUPPORT_DENY_ACL;
        return nfsd4_encode_uint32_t(xdr, mask);
}

static __be32 nfsd4_encode_fattr4_acl(struct xdr_stream *xdr,
                                      const struct nfsd4_fattr_args *args)
{
        struct nfs4_acl *acl = args->acl;
        struct nfs4_ace *ace;
        __be32 status;

        /* nfsace4<> */
        if (!acl) {
                if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                        return nfserr_resource;
        } else {
                if (xdr_stream_encode_u32(xdr, acl->naces) != XDR_UNIT)
                        return nfserr_resource;
                for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
                        status = nfsd4_encode_nfsace4(xdr, args->rqstp, ace);
                        if (status != nfs_ok)
                                return status;
                }
        }
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_filehandle(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_nfs_fh4(xdr, &args->fhp->fh_handle);
}

static __be32 nfsd4_encode_fattr4_fileid(struct xdr_stream *xdr,
                                         const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, args->stat.ino);
}

static __be32 nfsd4_encode_fattr4_files_avail(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, args->statfs.f_ffree);
}

static __be32 nfsd4_encode_fattr4_files_free(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, args->statfs.f_ffree);
}

static __be32 nfsd4_encode_fattr4_files_total(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, args->statfs.f_files);
}

static __be32 nfsd4_encode_fattr4_fs_locations(struct xdr_stream *xdr,
                                               const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_fs_locations4(xdr, args->rqstp, args->exp);
}

static __be32 nfsd4_encode_fattr4_maxfilesize(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        struct super_block *sb = args->exp->ex_path.mnt->mnt_sb;

        return nfsd4_encode_uint64_t(xdr, sb->s_maxbytes);
}

static __be32 nfsd4_encode_fattr4_maxlink(struct xdr_stream *xdr,
                                          const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint32_t(xdr, 255);
}

static __be32 nfsd4_encode_fattr4_maxname(struct xdr_stream *xdr,
                                          const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint32_t(xdr, args->statfs.f_namelen);
}

static __be32 nfsd4_encode_fattr4_maxread(struct xdr_stream *xdr,
                                          const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, svc_max_payload(args->rqstp));
}

static __be32 nfsd4_encode_fattr4_maxwrite(struct xdr_stream *xdr,
                                           const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, svc_max_payload(args->rqstp));
}

static __be32 nfsd4_encode_fattr4_mode(struct xdr_stream *xdr,
                                       const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_mode4(xdr, args->stat.mode & S_IALLUGO);
}

static __be32 nfsd4_encode_fattr4_numlinks(struct xdr_stream *xdr,
                                           const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint32_t(xdr, args->stat.nlink);
}

static __be32 nfsd4_encode_fattr4_owner(struct xdr_stream *xdr,
                                        const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_user(xdr, args->rqstp, args->stat.uid);
}

static __be32 nfsd4_encode_fattr4_owner_group(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_group(xdr, args->rqstp, args->stat.gid);
}

static __be32 nfsd4_encode_fattr4_rawdev(struct xdr_stream *xdr,
                                         const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_specdata4(xdr, MAJOR(args->stat.rdev),
                                      MINOR(args->stat.rdev));
}

static __be32 nfsd4_encode_fattr4_space_avail(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        u64 avail = (u64)args->statfs.f_bavail * (u64)args->statfs.f_bsize;

        return nfsd4_encode_uint64_t(xdr, avail);
}

static __be32 nfsd4_encode_fattr4_space_free(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        u64 free = (u64)args->statfs.f_bfree * (u64)args->statfs.f_bsize;

        return nfsd4_encode_uint64_t(xdr, free);
}

static __be32 nfsd4_encode_fattr4_space_total(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        u64 total = (u64)args->statfs.f_blocks * (u64)args->statfs.f_bsize;

        return nfsd4_encode_uint64_t(xdr, total);
}

static __be32 nfsd4_encode_fattr4_space_used(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint64_t(xdr, (u64)args->stat.blocks << 9);
}

static __be32 nfsd4_encode_fattr4_time_access(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_nfstime4(xdr, &args->stat.atime);
}

static __be32 nfsd4_encode_fattr4_time_create(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_nfstime4(xdr, &args->stat.btime);
}

/*
 * ctime (in NFSv4, time_metadata) is not writeable, and the client
 * doesn't really care what resolution could theoretically be stored by
 * the filesystem.
 *
 * The client cares how close together changes can be while still
 * guaranteeing ctime changes.  For most filesystems (which have
 * timestamps with nanosecond fields) that is limited by the resolution
 * of the time returned from current_time() (which I'm assuming to be
 * 1/HZ).
 */
static __be32 nfsd4_encode_fattr4_time_delta(struct xdr_stream *xdr,
                                             const struct nfsd4_fattr_args *args)
{
        const struct inode *inode = d_inode(args->dentry);
        u32 ns = max_t(u32, NSEC_PER_SEC/HZ, inode->i_sb->s_time_gran);
        struct timespec64 ts = ns_to_timespec64(ns);

        return nfsd4_encode_nfstime4(xdr, &ts);
}

static __be32 nfsd4_encode_fattr4_time_metadata(struct xdr_stream *xdr,
                                                const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_nfstime4(xdr, &args->stat.ctime);
}

static __be32 nfsd4_encode_fattr4_time_modify(struct xdr_stream *xdr,
                                              const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_nfstime4(xdr, &args->stat.mtime);
}

static __be32 nfsd4_encode_fattr4_mounted_on_fileid(struct xdr_stream *xdr,
                                                    const struct nfsd4_fattr_args *args)
{
        u64 ino;
        int err;

        if (!args->ignore_crossmnt &&
            args->dentry == args->exp->ex_path.mnt->mnt_root) {
                err = nfsd4_get_mounted_on_ino(args->exp, &ino);
                if (err)
                        return nfserrno(err);
        } else
                ino = args->stat.ino;

        return nfsd4_encode_uint64_t(xdr, ino);
}

#ifdef CONFIG_NFSD_PNFS

static __be32 nfsd4_encode_fattr4_fs_layout_types(struct xdr_stream *xdr,
                                                  const struct nfsd4_fattr_args *args)
{
        unsigned long mask = args->exp->ex_layout_types;
        int i;

        /* Hamming weight of @mask is the number of layout types to return */
        if (xdr_stream_encode_u32(xdr, hweight_long(mask)) != XDR_UNIT)
                return nfserr_resource;
        for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
                if (mask & BIT(i)) {
                        /* layouttype4 */
                        if (xdr_stream_encode_u32(xdr, i) != XDR_UNIT)
                                return nfserr_resource;
                }
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_layout_types(struct xdr_stream *xdr,
                                               const struct nfsd4_fattr_args *args)
{
        unsigned long mask = args->exp->ex_layout_types;
        int i;

        /* Hamming weight of @mask is the number of layout types to return */
        if (xdr_stream_encode_u32(xdr, hweight_long(mask)) != XDR_UNIT)
                return nfserr_resource;
        for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
                if (mask & BIT(i)) {
                        /* layouttype4 */
                        if (xdr_stream_encode_u32(xdr, i) != XDR_UNIT)
                                return nfserr_resource;
                }
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_layout_blksize(struct xdr_stream *xdr,
                                                 const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_uint32_t(xdr, args->stat.blksize);
}

#endif

static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr,
                                                     const struct nfsd4_fattr_args *args)
{
        struct nfsd4_compoundres *resp = args->rqstp->rq_resp;
        u32 supp[3];

        memcpy(supp, nfsd_suppattrs[resp->cstate.minorversion], sizeof(supp));
        if (!IS_POSIXACL(d_inode(args->dentry)))
                supp[0] &= ~FATTR4_WORD0_ACL;
        if (!args->contextsupport)
                supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;

        supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
        supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
        supp[2] &= NFSD_SUPPATTR_EXCLCREAT_WORD2;

        return nfsd4_encode_bitmap4(xdr, supp[0], supp[1], supp[2]);
}

/*
 * Copied from generic_remap_checks/generic_remap_file_range_prep.
 *
 * These generic functions use the file system's s_blocksize, but
 * individual file systems aren't required to use
 * generic_remap_file_range_prep. Until there is a mechanism for
 * determining a particular file system's (or file's) clone block
 * size, this is the best NFSD can do.
 */
static __be32 nfsd4_encode_fattr4_clone_blksize(struct xdr_stream *xdr,
                                                const struct nfsd4_fattr_args *args)
{
        struct inode *inode = d_inode(args->dentry);

        return nfsd4_encode_uint32_t(xdr, inode->i_sb->s_blocksize);
}

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
static __be32 nfsd4_encode_fattr4_sec_label(struct xdr_stream *xdr,
                                            const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_security_label(xdr, args->rqstp, &args->context);
}
#endif

static __be32 nfsd4_encode_fattr4_xattr_support(struct xdr_stream *xdr,
                                                const struct nfsd4_fattr_args *args)
{
        int err = xattr_supports_user_prefix(d_inode(args->dentry));

        return nfsd4_encode_bool(xdr, err == 0);
}

#define NFSD_OA_SHARE_ACCESS    (BIT(OPEN_ARGS_SHARE_ACCESS_READ)       | \
                                 BIT(OPEN_ARGS_SHARE_ACCESS_WRITE)      | \
                                 BIT(OPEN_ARGS_SHARE_ACCESS_BOTH))

#define NFSD_OA_SHARE_DENY      (BIT(OPEN_ARGS_SHARE_DENY_NONE)         | \
                                 BIT(OPEN_ARGS_SHARE_DENY_READ)         | \
                                 BIT(OPEN_ARGS_SHARE_DENY_WRITE)        | \
                                 BIT(OPEN_ARGS_SHARE_DENY_BOTH))

#define NFSD_OA_SHARE_ACCESS_WANT       (BIT(OPEN_ARGS_SHARE_ACCESS_WANT_ANY_DELEG)             | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_NO_DELEG)              | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_CANCEL)                | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS)      | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_OPEN_XOR_DELEGATION))

#define NFSD_OA_OPEN_CLAIM      (BIT(OPEN_ARGS_OPEN_CLAIM_NULL)         | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_PREVIOUS)     | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_DELEGATE_CUR) | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_DELEGATE_PREV)| \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_FH)           | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_DELEG_CUR_FH) | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_DELEG_PREV_FH))

#define NFSD_OA_CREATE_MODE     (BIT(OPEN_ARGS_CREATEMODE_UNCHECKED4)   | \
                                 BIT(OPEN_ARGS_CREATE_MODE_GUARDED)     | \
                                 BIT(OPEN_ARGS_CREATEMODE_EXCLUSIVE4)   | \
                                 BIT(OPEN_ARGS_CREATE_MODE_EXCLUSIVE4_1))

static uint32_t oa_share_access = NFSD_OA_SHARE_ACCESS;
static uint32_t oa_share_deny = NFSD_OA_SHARE_DENY;
static uint32_t oa_share_access_want = NFSD_OA_SHARE_ACCESS_WANT;
static uint32_t oa_open_claim = NFSD_OA_OPEN_CLAIM;
static uint32_t oa_create_mode = NFSD_OA_CREATE_MODE;

static const struct open_arguments4 nfsd_open_arguments = {
        .oa_share_access = { .count = 1, .element = &oa_share_access },
        .oa_share_deny = { .count = 1, .element = &oa_share_deny },
        .oa_share_access_want = { .count = 1, .element = &oa_share_access_want },
        .oa_open_claim = { .count = 1, .element = &oa_open_claim },
        .oa_create_mode = { .count = 1, .element = &oa_create_mode },
};

static __be32 nfsd4_encode_fattr4_open_arguments(struct xdr_stream *xdr,
                                                 const struct nfsd4_fattr_args *args)
{
        if (!xdrgen_encode_fattr4_open_arguments(xdr, &nfsd_open_arguments))
                return nfserr_resource;
        return nfs_ok;
}

#ifdef CONFIG_NFSD_V4_POSIX_ACLS

static __be32 nfsd4_encode_fattr4_acl_trueform(struct xdr_stream *xdr,
                                               const struct nfsd4_fattr_args *args)
{
        aclmodel4 trueform = ACL_MODEL_NONE;

        if (IS_POSIXACL(d_inode(args->dentry)))
                trueform = ACL_MODEL_POSIX_DRAFT;
        if (!xdrgen_encode_aclmodel4(xdr, trueform))
                return nfserr_resource;
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_acl_trueform_scope(struct xdr_stream *xdr,
                                                     const struct nfsd4_fattr_args *args)
{
        if (!xdrgen_encode_aclscope4(xdr, ACL_SCOPE_FILE_SYSTEM))
                return nfserr_resource;
        return nfs_ok;
}

static __be32 nfsd4_encode_fattr4_posix_default_acl(struct xdr_stream *xdr,
                                                    const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_posixacl(xdr, args->rqstp, args->dpacl);
}

static __be32 nfsd4_encode_fattr4_posix_access_acl(struct xdr_stream *xdr,
                                                   const struct nfsd4_fattr_args *args)
{
        return nfsd4_encode_posixacl(xdr, args->rqstp, args->pacl);
}

#endif /* CONFIG_NFSD_V4_POSIX_ACLS */

static const nfsd4_enc_attr nfsd4_enc_fattr4_encode_ops[] = {
        [FATTR4_SUPPORTED_ATTRS]        = nfsd4_encode_fattr4_supported_attrs,
        [FATTR4_TYPE]                   = nfsd4_encode_fattr4_type,
        [FATTR4_FH_EXPIRE_TYPE]         = nfsd4_encode_fattr4_fh_expire_type,
        [FATTR4_CHANGE]                 = nfsd4_encode_fattr4_change,
        [FATTR4_SIZE]                   = nfsd4_encode_fattr4_size,
        [FATTR4_LINK_SUPPORT]           = nfsd4_encode_fattr4__true,
        [FATTR4_SYMLINK_SUPPORT]        = nfsd4_encode_fattr4__true,
        [FATTR4_NAMED_ATTR]             = nfsd4_encode_fattr4__false,
        [FATTR4_FSID]                   = nfsd4_encode_fattr4_fsid,
        [FATTR4_UNIQUE_HANDLES]         = nfsd4_encode_fattr4__true,
        [FATTR4_LEASE_TIME]             = nfsd4_encode_fattr4_lease_time,
        [FATTR4_RDATTR_ERROR]           = nfsd4_encode_fattr4_rdattr_error,
        [FATTR4_ACL]                    = nfsd4_encode_fattr4_acl,
        [FATTR4_ACLSUPPORT]             = nfsd4_encode_fattr4_aclsupport,
        [FATTR4_ARCHIVE]                = nfsd4_encode_fattr4__noop,
        [FATTR4_CANSETTIME]             = nfsd4_encode_fattr4__true,
        [FATTR4_CASE_INSENSITIVE]       = nfsd4_encode_fattr4__false,
        [FATTR4_CASE_PRESERVING]        = nfsd4_encode_fattr4__true,
        [FATTR4_CHOWN_RESTRICTED]       = nfsd4_encode_fattr4__true,
        [FATTR4_FILEHANDLE]             = nfsd4_encode_fattr4_filehandle,
        [FATTR4_FILEID]                 = nfsd4_encode_fattr4_fileid,
        [FATTR4_FILES_AVAIL]            = nfsd4_encode_fattr4_files_avail,
        [FATTR4_FILES_FREE]             = nfsd4_encode_fattr4_files_free,
        [FATTR4_FILES_TOTAL]            = nfsd4_encode_fattr4_files_total,
        [FATTR4_FS_LOCATIONS]           = nfsd4_encode_fattr4_fs_locations,
        [FATTR4_HIDDEN]                 = nfsd4_encode_fattr4__noop,
        [FATTR4_HOMOGENEOUS]            = nfsd4_encode_fattr4__true,
        [FATTR4_MAXFILESIZE]            = nfsd4_encode_fattr4_maxfilesize,
        [FATTR4_MAXLINK]                = nfsd4_encode_fattr4_maxlink,
        [FATTR4_MAXNAME]                = nfsd4_encode_fattr4_maxname,
        [FATTR4_MAXREAD]                = nfsd4_encode_fattr4_maxread,
        [FATTR4_MAXWRITE]               = nfsd4_encode_fattr4_maxwrite,
        [FATTR4_MIMETYPE]               = nfsd4_encode_fattr4__noop,
        [FATTR4_MODE]                   = nfsd4_encode_fattr4_mode,
        [FATTR4_NO_TRUNC]               = nfsd4_encode_fattr4__true,
        [FATTR4_NUMLINKS]               = nfsd4_encode_fattr4_numlinks,
        [FATTR4_OWNER]                  = nfsd4_encode_fattr4_owner,
        [FATTR4_OWNER_GROUP]            = nfsd4_encode_fattr4_owner_group,
        [FATTR4_QUOTA_AVAIL_HARD]       = nfsd4_encode_fattr4__noop,
        [FATTR4_QUOTA_AVAIL_SOFT]       = nfsd4_encode_fattr4__noop,
        [FATTR4_QUOTA_USED]             = nfsd4_encode_fattr4__noop,
        [FATTR4_RAWDEV]                 = nfsd4_encode_fattr4_rawdev,
        [FATTR4_SPACE_AVAIL]            = nfsd4_encode_fattr4_space_avail,
        [FATTR4_SPACE_FREE]             = nfsd4_encode_fattr4_space_free,
        [FATTR4_SPACE_TOTAL]            = nfsd4_encode_fattr4_space_total,
        [FATTR4_SPACE_USED]             = nfsd4_encode_fattr4_space_used,
        [FATTR4_SYSTEM]                 = nfsd4_encode_fattr4__noop,
        [FATTR4_TIME_ACCESS]            = nfsd4_encode_fattr4_time_access,
        [FATTR4_TIME_ACCESS_SET]        = nfsd4_encode_fattr4__noop,
        [FATTR4_TIME_BACKUP]            = nfsd4_encode_fattr4__noop,
        [FATTR4_TIME_CREATE]            = nfsd4_encode_fattr4_time_create,
        [FATTR4_TIME_DELTA]             = nfsd4_encode_fattr4_time_delta,
        [FATTR4_TIME_METADATA]          = nfsd4_encode_fattr4_time_metadata,
        [FATTR4_TIME_MODIFY]            = nfsd4_encode_fattr4_time_modify,
        [FATTR4_TIME_MODIFY_SET]        = nfsd4_encode_fattr4__noop,
        [FATTR4_MOUNTED_ON_FILEID]      = nfsd4_encode_fattr4_mounted_on_fileid,
        [FATTR4_DIR_NOTIF_DELAY]        = nfsd4_encode_fattr4__noop,
        [FATTR4_DIRENT_NOTIF_DELAY]     = nfsd4_encode_fattr4__noop,
        [FATTR4_DACL]                   = nfsd4_encode_fattr4__noop,
        [FATTR4_SACL]                   = nfsd4_encode_fattr4__noop,
        [FATTR4_CHANGE_POLICY]          = nfsd4_encode_fattr4__noop,
        [FATTR4_FS_STATUS]              = nfsd4_encode_fattr4__noop,

#ifdef CONFIG_NFSD_PNFS
        [FATTR4_FS_LAYOUT_TYPES]        = nfsd4_encode_fattr4_fs_layout_types,
        [FATTR4_LAYOUT_HINT]            = nfsd4_encode_fattr4__noop,
        [FATTR4_LAYOUT_TYPES]           = nfsd4_encode_fattr4_layout_types,
        [FATTR4_LAYOUT_BLKSIZE]         = nfsd4_encode_fattr4_layout_blksize,
        [FATTR4_LAYOUT_ALIGNMENT]       = nfsd4_encode_fattr4__noop,
#else
        [FATTR4_FS_LAYOUT_TYPES]        = nfsd4_encode_fattr4__noop,
        [FATTR4_LAYOUT_HINT]            = nfsd4_encode_fattr4__noop,
        [FATTR4_LAYOUT_TYPES]           = nfsd4_encode_fattr4__noop,
        [FATTR4_LAYOUT_BLKSIZE]         = nfsd4_encode_fattr4__noop,
        [FATTR4_LAYOUT_ALIGNMENT]       = nfsd4_encode_fattr4__noop,
#endif

        [FATTR4_FS_LOCATIONS_INFO]      = nfsd4_encode_fattr4__noop,
        [FATTR4_MDSTHRESHOLD]           = nfsd4_encode_fattr4__noop,
        [FATTR4_RETENTION_GET]          = nfsd4_encode_fattr4__noop,
        [FATTR4_RETENTION_SET]          = nfsd4_encode_fattr4__noop,
        [FATTR4_RETENTEVT_GET]          = nfsd4_encode_fattr4__noop,
        [FATTR4_RETENTEVT_SET]          = nfsd4_encode_fattr4__noop,
        [FATTR4_RETENTION_HOLD]         = nfsd4_encode_fattr4__noop,
        [FATTR4_MODE_SET_MASKED]        = nfsd4_encode_fattr4__noop,
        [FATTR4_SUPPATTR_EXCLCREAT]     = nfsd4_encode_fattr4_suppattr_exclcreat,
        [FATTR4_FS_CHARSET_CAP]         = nfsd4_encode_fattr4__noop,
        [FATTR4_CLONE_BLKSIZE]          = nfsd4_encode_fattr4_clone_blksize,
        [FATTR4_SPACE_FREED]            = nfsd4_encode_fattr4__noop,
        [FATTR4_CHANGE_ATTR_TYPE]       = nfsd4_encode_fattr4__noop,

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        [FATTR4_SEC_LABEL]              = nfsd4_encode_fattr4_sec_label,
#else
        [FATTR4_SEC_LABEL]              = nfsd4_encode_fattr4__noop,
#endif

        [FATTR4_MODE_UMASK]             = nfsd4_encode_fattr4__noop,
        [FATTR4_XATTR_SUPPORT]          = nfsd4_encode_fattr4_xattr_support,
        [FATTR4_TIME_DELEG_ACCESS]      = nfsd4_encode_fattr4__inval,
        [FATTR4_TIME_DELEG_MODIFY]      = nfsd4_encode_fattr4__inval,
        [FATTR4_OPEN_ARGUMENTS]         = nfsd4_encode_fattr4_open_arguments,

        /* Reserved */
        [87]                            = nfsd4_encode_fattr4__inval,
        [88]                            = nfsd4_encode_fattr4__inval,

#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        [FATTR4_ACL_TRUEFORM]           = nfsd4_encode_fattr4_acl_trueform,
        [FATTR4_ACL_TRUEFORM_SCOPE]     = nfsd4_encode_fattr4_acl_trueform_scope,
        [FATTR4_POSIX_DEFAULT_ACL]      = nfsd4_encode_fattr4_posix_default_acl,
        [FATTR4_POSIX_ACCESS_ACL]       = nfsd4_encode_fattr4_posix_access_acl,
#else
        [FATTR4_ACL_TRUEFORM]           = nfsd4_encode_fattr4__noop,
        [FATTR4_ACL_TRUEFORM_SCOPE]     = nfsd4_encode_fattr4__noop,
        [FATTR4_POSIX_DEFAULT_ACL]      = nfsd4_encode_fattr4__noop,
        [FATTR4_POSIX_ACCESS_ACL]       = nfsd4_encode_fattr4__noop,
#endif
};

/*
 * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
 * ourselves.
 */
static __be32
nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                    struct svc_fh *fhp, struct svc_export *exp,
                    struct dentry *dentry, const u32 *bmval,
                    int ignore_crossmnt)
{
        DECLARE_BITMAP(attr_bitmap, ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops));
        struct nfs4_delegation *dp = NULL;
        struct nfsd4_fattr_args args;
        struct svc_fh *tempfh = NULL;
        int starting_len = xdr->buf->len;
        unsigned int attrlen_offset;
        __be32 attrlen, status;
        u32 attrmask[3];
        int err;
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        u32 minorversion = resp->cstate.minorversion;
        struct path path = {
                .mnt    = exp->ex_path.mnt,
                .dentry = dentry,
        };
        unsigned long bit;

        WARN_ON_ONCE(bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1);
        WARN_ON_ONCE(!nfsd_attrs_supported(minorversion, bmval));

        args.rqstp = rqstp;
        args.exp = exp;
        args.dentry = dentry;
        args.ignore_crossmnt = (ignore_crossmnt != 0);
        args.acl = NULL;
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        args.context.context = NULL;
#endif
#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        args.dpacl = NULL;
        args.pacl = NULL;
#endif

        /*
         * Make a local copy of the attribute bitmap that can be modified.
         */
        attrmask[0] = bmval[0];
        attrmask[1] = bmval[1];
        attrmask[2] = bmval[2];

        args.rdattr_err = 0;
        if (exp->ex_fslocs.migrated) {
                status = fattr_handle_absent_fs(&attrmask[0], &attrmask[1],
                                                &attrmask[2], &args.rdattr_err);
                if (status)
                        goto out;
        }
        if ((attrmask[0] & (FATTR4_WORD0_CHANGE |
                            FATTR4_WORD0_SIZE)) ||
            (attrmask[1] & (FATTR4_WORD1_TIME_ACCESS |
                            FATTR4_WORD1_TIME_MODIFY |
                            FATTR4_WORD1_TIME_METADATA))) {
                status = nfsd4_deleg_getattr_conflict(rqstp, dentry, &dp);
                if (status)
                        goto out;
        }

        err = vfs_getattr(&path, &args.stat,
                          STATX_BASIC_STATS | STATX_BTIME | STATX_CHANGE_COOKIE,
                          AT_STATX_SYNC_AS_STAT);
        if (dp) {
                struct nfs4_cb_fattr *ncf = &dp->dl_cb_fattr;

                if (ncf->ncf_file_modified) {
                        ++ncf->ncf_initial_cinfo;
                        args.stat.size = ncf->ncf_cur_fsize;
                        if (!timespec64_is_epoch(&ncf->ncf_cb_mtime))
                                args.stat.mtime = ncf->ncf_cb_mtime;
                }
                args.change_attr = ncf->ncf_initial_cinfo;

                if (!timespec64_is_epoch(&ncf->ncf_cb_atime))
                        args.stat.atime = ncf->ncf_cb_atime;

                nfs4_put_stid(&dp->dl_stid);
        } else {
                args.change_attr = nfsd4_change_attribute(&args.stat);
        }

        if (err)
                goto out_nfserr;

        if (!(args.stat.result_mask & STATX_BTIME))
                /* underlying FS does not offer btime so we can't share it */
                attrmask[1] &= ~FATTR4_WORD1_TIME_CREATE;
        if ((attrmask[0] & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
                        FATTR4_WORD0_FILES_TOTAL | FATTR4_WORD0_MAXNAME)) ||
            (attrmask[1] & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
                       FATTR4_WORD1_SPACE_TOTAL))) {
                err = vfs_statfs(&path, &args.statfs);
                if (err)
                        goto out_nfserr;
        }
        if ((attrmask[0] & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) &&
            !fhp) {
                tempfh = kmalloc_obj(struct svc_fh);
                status = nfserr_jukebox;
                if (!tempfh)
                        goto out;
                fh_init(tempfh, NFS4_FHSIZE);
                status = fh_compose(tempfh, exp, dentry, NULL);
                if (status)
                        goto out;
                args.fhp = tempfh;
        } else
                args.fhp = fhp;

        if (attrmask[0] & FATTR4_WORD0_ACL) {
                err = nfsd4_get_nfs4_acl(rqstp, dentry, &args.acl);
                if (err == -EOPNOTSUPP)
                        attrmask[0] &= ~FATTR4_WORD0_ACL;
                else if (err == -EINVAL) {
                        status = nfserr_attrnotsupp;
                        goto out;
                } else if (err != 0)
                        goto out_nfserr;
        }

        args.contextsupport = false;

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        if ((attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) ||
             attrmask[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
                if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
                        err = security_inode_getsecctx(d_inode(dentry),
                                                &args.context);
                else
                        err = -EOPNOTSUPP;
                args.contextsupport = (err == 0);
                if (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL) {
                        if (err == -EOPNOTSUPP)
                                attrmask[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
                        else if (err)
                                goto out_nfserr;
                }
        }
#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */

#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        if (attrmask[2] & FATTR4_WORD2_POSIX_DEFAULT_ACL) {
                struct inode *inode = d_inode(dentry);
                struct posix_acl *dpacl;

                if (S_ISDIR(inode->i_mode)) {
                        dpacl = get_inode_acl(inode, ACL_TYPE_DEFAULT);
                        if (IS_ERR(dpacl)) {
                                switch (PTR_ERR(dpacl)) {
                                case -EOPNOTSUPP:
                                        attrmask[2] &= ~FATTR4_WORD2_POSIX_DEFAULT_ACL;
                                        break;
                                case -EINVAL:
                                        status = nfserr_attrnotsupp;
                                        goto out;
                                default:
                                        err = PTR_ERR(dpacl);
                                        goto out_nfserr;
                                }
                        } else {
                                args.dpacl = dpacl;
                        }
                }
        }
        if (attrmask[2] & FATTR4_WORD2_POSIX_ACCESS_ACL) {
                struct inode *inode = d_inode(dentry);
                struct posix_acl *pacl;

                pacl = get_inode_acl(inode, ACL_TYPE_ACCESS);
                if (!pacl)
                        pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
                if (IS_ERR(pacl)) {
                        switch (PTR_ERR(pacl)) {
                        case -EOPNOTSUPP:
                                attrmask[2] &= ~FATTR4_WORD2_POSIX_ACCESS_ACL;
                                break;
                        case -EINVAL:
                                status = nfserr_attrnotsupp;
                                goto out;
                        default:
                                err = PTR_ERR(pacl);
                                goto out_nfserr;
                        }
                } else {
                        args.pacl = pacl;
                }
        }
#endif /* CONFIG_NFSD_V4_POSIX_ACLS */

        /* attrmask */
        status = nfsd4_encode_bitmap4(xdr, attrmask[0], attrmask[1],
                                      attrmask[2]);
        if (status)
                goto out;

        /* attr_vals */
        attrlen_offset = xdr->buf->len;
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT)))
                goto out_resource;
        bitmap_from_arr32(attr_bitmap, attrmask,
                          ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops));
        for_each_set_bit(bit, attr_bitmap,
                         ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops)) {
                status = nfsd4_enc_fattr4_encode_ops[bit](xdr, &args);
                if (status != nfs_ok)
                        goto out;
        }
        attrlen = cpu_to_be32(xdr->buf->len - attrlen_offset - XDR_UNIT);
        write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, XDR_UNIT);
        status = nfs_ok;

out:
#ifdef CONFIG_NFSD_V4_POSIX_ACLS
        if (args.dpacl)
                posix_acl_release(args.dpacl);
        if (args.pacl)
                posix_acl_release(args.pacl);
#endif /* CONFIG_NFSD_V4_POSIX_ACLS */
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        if (args.context.context)
                security_release_secctx(&args.context);
#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
        kfree(args.acl);
        if (tempfh) {
                fh_put(tempfh);
                kfree(tempfh);
        }
        if (status)
                xdr_truncate_encode(xdr, starting_len);
        return status;
out_nfserr:
        status = nfserrno(err);
        goto out;
out_resource:
        status = nfserr_resource;
        goto out;
}

static void svcxdr_init_encode_from_buffer(struct xdr_stream *xdr,
                                struct xdr_buf *buf, __be32 *p, int bytes)
{
        xdr->scratch.iov_len = 0;
        memset(buf, 0, sizeof(struct xdr_buf));
        buf->head[0].iov_base = p;
        buf->head[0].iov_len = 0;
        buf->len = 0;
        xdr->buf = buf;
        xdr->iov = buf->head;
        xdr->p = p;
        xdr->end = (void *)p + bytes;
        buf->buflen = bytes;
}

__be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
                        struct svc_fh *fhp, struct svc_export *exp,
                        struct dentry *dentry, u32 *bmval,
                        struct svc_rqst *rqstp, int ignore_crossmnt)
{
        struct xdr_buf dummy;
        struct xdr_stream xdr;
        __be32 ret;

        svcxdr_init_encode_from_buffer(&xdr, &dummy, *p, words << 2);
        ret = nfsd4_encode_fattr4(rqstp, &xdr, fhp, exp, dentry, bmval,
                                  ignore_crossmnt);
        *p = xdr.p;
        return ret;
}

/*
 * The buffer space for this field was reserved during a previous
 * call to nfsd4_encode_entry4().
 */
static void nfsd4_encode_entry4_nfs_cookie4(const struct nfsd4_readdir *readdir,
                                            u64 offset)
{
        __be64 cookie = cpu_to_be64(offset);
        struct xdr_stream *xdr = readdir->xdr;

        if (!readdir->cookie_offset)
                return;
        write_bytes_to_xdr_buf(xdr->buf, readdir->cookie_offset, &cookie,
                               sizeof(cookie));
}

static inline int attributes_need_mount(u32 *bmval)
{
        if (bmval[0] & ~(FATTR4_WORD0_RDATTR_ERROR | FATTR4_WORD0_LEASE_TIME))
                return 1;
        if (bmval[1] & ~FATTR4_WORD1_MOUNTED_ON_FILEID)
                return 1;
        return 0;
}

static __be32
nfsd4_encode_entry4_fattr(struct nfsd4_readdir *cd, const char *name,
                          int namlen)
{
        struct svc_export *exp = cd->rd_fhp->fh_export;
        struct dentry *dentry;
        __be32 nfserr;
        int ignore_crossmnt = 0;

        dentry = lookup_one_positive_unlocked(&nop_mnt_idmap,
                                              &QSTR_LEN(name, namlen),
                                              cd->rd_fhp->fh_dentry);
        if (IS_ERR(dentry))
                return nfserrno(PTR_ERR(dentry));

        exp_get(exp);
        /*
         * In the case of a mountpoint, the client may be asking for
         * attributes that are only properties of the underlying filesystem
         * as opposed to the cross-mounted file system. In such a case,
         * we will not follow the cross mount and will fill the attribtutes
         * directly from the mountpoint dentry.
         */
        if (nfsd_mountpoint(dentry, exp)) {
                int err;

                if (!(exp->ex_flags & NFSEXP_V4ROOT)
                                && !attributes_need_mount(cd->rd_bmval)) {
                        ignore_crossmnt = 1;
                        goto out_encode;
                }
                /*
                 * Why the heck aren't we just using nfsd_lookup??
                 * Different "."/".." handling?  Something else?
                 * At least, add a comment here to explain....
                 */
                err = nfsd_cross_mnt(cd->rd_rqstp, &dentry, &exp);
                if (err) {
                        nfserr = nfserrno(err);
                        goto out_put;
                }
                nfserr = check_nfsd_access(exp, cd->rd_rqstp, false);
                if (nfserr)
                        goto out_put;

        }
out_encode:
        nfserr = nfsd4_encode_fattr4(cd->rd_rqstp, cd->xdr, NULL, exp, dentry,
                                     cd->rd_bmval, ignore_crossmnt);
out_put:
        dput(dentry);
        exp_put(exp);
        return nfserr;
}

static __be32
nfsd4_encode_entry4_rdattr_error(struct xdr_stream *xdr, __be32 nfserr)
{
        __be32 status;

        /* attrmask */
        status = nfsd4_encode_bitmap4(xdr, FATTR4_WORD0_RDATTR_ERROR, 0, 0);
        if (status != nfs_ok)
                return status;
        /* attr_vals */
        if (xdr_stream_encode_u32(xdr, XDR_UNIT) != XDR_UNIT)
                return nfserr_resource;
        /* rdattr_error */
        if (xdr_stream_encode_be32(xdr, nfserr) != XDR_UNIT)
                return nfserr_resource;
        return nfs_ok;
}

static int
nfsd4_encode_entry4(void *ccdv, const char *name, int namlen,
                    loff_t offset, u64 ino, unsigned int d_type)
{
        struct readdir_cd *ccd = ccdv;
        struct nfsd4_readdir *cd = container_of(ccd, struct nfsd4_readdir, common);
        struct xdr_stream *xdr = cd->xdr;
        int start_offset = xdr->buf->len;
        int cookie_offset;
        u32 name_and_cookie;
        int entry_bytes;
        __be32 nfserr = nfserr_toosmall;

        /* In nfsv4, "." and ".." never make it onto the wire.. */
        if (name && isdotent(name, namlen)) {
                cd->common.err = nfs_ok;
                return 0;
        }

        /* Encode the previous entry's cookie value */
        nfsd4_encode_entry4_nfs_cookie4(cd, offset);

        if (xdr_stream_encode_item_present(xdr) != XDR_UNIT)
                goto fail;

        /* Reserve send buffer space for this entry's cookie value. */
        cookie_offset = xdr->buf->len;
        if (nfsd4_encode_nfs_cookie4(xdr, OFFSET_MAX) != nfs_ok)
                goto fail;
        if (nfsd4_encode_component4(xdr, name, namlen) != nfs_ok)
                goto fail;
        nfserr = nfsd4_encode_entry4_fattr(cd, name, namlen);
        switch (nfserr) {
        case nfs_ok:
                break;
        case nfserr_resource:
                nfserr = nfserr_toosmall;
                goto fail;
        case nfserr_noent:
                xdr_truncate_encode(xdr, start_offset);
                goto skip_entry;
        case nfserr_jukebox:
                /*
                 * The pseudoroot should only display dentries that lead to
                 * exports. If we get EJUKEBOX here, then we can't tell whether
                 * this entry should be included. Just fail the whole READDIR
                 * with NFS4ERR_DELAY in that case, and hope that the situation
                 * will resolve itself by the client's next attempt.
                 */
                if (cd->rd_fhp->fh_export->ex_flags & NFSEXP_V4ROOT)
                        goto fail;
                fallthrough;
        default:
                /*
                 * If the client requested the RDATTR_ERROR attribute,
                 * we stuff the error code into this attribute
                 * and continue.  If this attribute was not requested,
                 * then in accordance with the spec, we fail the
                 * entire READDIR operation(!)
                 */
                if (!(cd->rd_bmval[0] & FATTR4_WORD0_RDATTR_ERROR))
                        goto fail;
                if (nfsd4_encode_entry4_rdattr_error(xdr, nfserr)) {
                        nfserr = nfserr_toosmall;
                        goto fail;
                }
        }
        nfserr = nfserr_toosmall;
        entry_bytes = xdr->buf->len - start_offset;
        if (entry_bytes > cd->rd_maxcount)
                goto fail;
        cd->rd_maxcount -= entry_bytes;
        /*
         * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and
         * notes that it could be zero. If it is zero, then the server
         * should enforce only the rd_maxcount value.
         */
        if (cd->rd_dircount) {
                name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8;
                if (name_and_cookie > cd->rd_dircount && cd->cookie_offset)
                        goto fail;
                cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie);
                if (!cd->rd_dircount)
                        cd->rd_maxcount = 0;
        }

        cd->cookie_offset = cookie_offset;
skip_entry:
        cd->common.err = nfs_ok;
        return 0;
fail:
        xdr_truncate_encode(xdr, start_offset);
        cd->common.err = nfserr;
        return -EINVAL;
}

static __be32
nfsd4_encode_verifier4(struct xdr_stream *xdr, const nfs4_verifier *verf)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
        if (!p)
                return nfserr_resource;
        memcpy(p, verf->data, sizeof(verf->data));
        return nfs_ok;
}

static __be32
nfsd4_encode_clientid4(struct xdr_stream *xdr, const clientid_t *clientid)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, sizeof(__be64));
        if (!p)
                return nfserr_resource;
        memcpy(p, clientid, sizeof(*clientid));
        return nfs_ok;
}

/* This is a frequently-encoded item; open-coded for speed */
static __be32
nfsd4_encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(sid->si_generation);
        memcpy(p, &sid->si_opaque, sizeof(sid->si_opaque));
        return nfs_ok;
}

static __be32
nfsd4_encode_sessionid4(struct xdr_stream *xdr,
                        const struct nfs4_sessionid *sessionid)
{
        return nfsd4_encode_opaque_fixed(xdr, sessionid->data,
                                         NFS4_MAX_SESSIONID_LEN);
}

static __be32
nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr,
                    union nfsd4_op_u *u)
{
        struct nfsd4_access *access = &u->access;
        struct xdr_stream *xdr = resp->xdr;
        __be32 status;

        /* supported */
        status = nfsd4_encode_uint32_t(xdr, access->ac_supported);
        if (status != nfs_ok)
                return status;
        /* access */
        return nfsd4_encode_uint32_t(xdr, access->ac_resp_access);
}

static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr,
                                                union nfsd4_op_u *u)
{
        struct nfsd4_bind_conn_to_session *bcts = &u->bind_conn_to_session;
        struct xdr_stream *xdr = resp->xdr;

        /* bctsr_sessid */
        nfserr = nfsd4_encode_sessionid4(xdr, &bcts->sessionid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* bctsr_dir */
        if (xdr_stream_encode_u32(xdr, bcts->dir) != XDR_UNIT)
                return nfserr_resource;
        /* bctsr_use_conn_in_rdma_mode */
        return nfsd4_encode_bool(xdr, false);
}

static __be32
nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr,
                   union nfsd4_op_u *u)
{
        struct nfsd4_close *close = &u->close;
        struct xdr_stream *xdr = resp->xdr;

        /* open_stateid */
        return nfsd4_encode_stateid4(xdr, &close->cl_stateid);
}


static __be32
nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr,
                    union nfsd4_op_u *u)
{
        struct nfsd4_commit *commit = &u->commit;

        return nfsd4_encode_verifier4(resp->xdr, &commit->co_verf);
}

static __be32
nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr,
                    union nfsd4_op_u *u)
{
        struct nfsd4_create *create = &u->create;
        struct xdr_stream *xdr = resp->xdr;

        /* cinfo */
        nfserr = nfsd4_encode_change_info4(xdr, &create->cr_cinfo);
        if (nfserr)
                return nfserr;
        /* attrset */
        return nfsd4_encode_bitmap4(xdr, create->cr_bmval[0],
                                    create->cr_bmval[1], create->cr_bmval[2]);
}

static __be32
nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr,
                     union nfsd4_op_u *u)
{
        struct nfsd4_getattr *getattr = &u->getattr;
        struct svc_fh *fhp = getattr->ga_fhp;
        struct xdr_stream *xdr = resp->xdr;

        /* obj_attributes */
        return nfsd4_encode_fattr4(resp->rqstp, xdr, fhp, fhp->fh_export,
                                   fhp->fh_dentry, getattr->ga_bmval, 0);
}

static __be32
nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr,
                   union nfsd4_op_u *u)
{
        struct xdr_stream *xdr = resp->xdr;
        struct svc_fh *fhp = u->getfh;

        /* object */
        return nfsd4_encode_nfs_fh4(xdr, &fhp->fh_handle);
}

static __be32
nfsd4_encode_lock_owner4(struct xdr_stream *xdr, const clientid_t *clientid,
                         const struct xdr_netobj *owner)
{
        __be32 status;

        /* clientid */
        status = nfsd4_encode_clientid4(xdr, clientid);
        if (status != nfs_ok)
                return status;
        /* owner */
        return nfsd4_encode_opaque(xdr, owner->data, owner->len);
}

static __be32
nfsd4_encode_lock4denied(struct xdr_stream *xdr,
                         const struct nfsd4_lock_denied *ld)
{
        __be32 status;

        /* offset */
        status = nfsd4_encode_offset4(xdr, ld->ld_start);
        if (status != nfs_ok)
                return status;
        /* length */
        status = nfsd4_encode_length4(xdr, ld->ld_length);
        if (status != nfs_ok)
                return status;
        /* locktype */
        if (xdr_stream_encode_u32(xdr, ld->ld_type) != XDR_UNIT)
                return nfserr_resource;
        /* owner */
        return nfsd4_encode_lock_owner4(xdr, &ld->ld_clientid,
                                        &ld->ld_owner);
}

static __be32
nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_lock *lock = &u->lock;
        struct xdr_stream *xdr = resp->xdr;
        __be32 status;

        switch (nfserr) {
        case nfs_ok:
                /* resok4 */
                status = nfsd4_encode_stateid4(xdr, &lock->lk_resp_stateid);
                break;
        case nfserr_denied:
                /* denied */
                status = nfsd4_encode_lock4denied(xdr, &lock->lk_denied);
                break;
        default:
                return nfserr;
        }
        return status != nfs_ok ? status : nfserr;
}

static __be32
nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr,
                   union nfsd4_op_u *u)
{
        struct nfsd4_lockt *lockt = &u->lockt;
        struct xdr_stream *xdr = resp->xdr;
        __be32 status;

        if (nfserr == nfserr_denied) {
                /* denied */
                status = nfsd4_encode_lock4denied(xdr, &lockt->lt_denied);
                if (status != nfs_ok)
                        return status;
        }
        return nfserr;
}

static __be32
nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr,
                   union nfsd4_op_u *u)
{
        struct nfsd4_locku *locku = &u->locku;
        struct xdr_stream *xdr = resp->xdr;

        /* lock_stateid */
        return nfsd4_encode_stateid4(xdr, &locku->lu_stateid);
}


static __be32
nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_link *link = &u->link;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_change_info4(xdr, &link->li_cinfo);
}

/*
 * This implementation does not yet support returning an ACE in an
 * OPEN that offers a delegation.
 */
static __be32
nfsd4_encode_open_nfsace4(struct xdr_stream *xdr)
{
        __be32 status;

        /* type */
        status = nfsd4_encode_acetype4(xdr, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
        if (status != nfs_ok)
                return nfserr_resource;
        /* flag */
        status = nfsd4_encode_aceflag4(xdr, 0);
        if (status != nfs_ok)
                return nfserr_resource;
        /* access mask */
        status = nfsd4_encode_acemask4(xdr, 0);
        if (status != nfs_ok)
                return nfserr_resource;
        /* who - empty for now */
        if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                return nfserr_resource;
        return nfs_ok;
}

static __be32
nfsd4_encode_open_read_delegation4(struct xdr_stream *xdr, struct nfsd4_open *open)
{
        __be32 status;

        /* stateid */
        status = nfsd4_encode_stateid4(xdr, &open->op_delegate_stateid);
        if (status != nfs_ok)
                return status;
        /* recall */
        status = nfsd4_encode_bool(xdr, open->op_recall);
        if (status != nfs_ok)
                return status;
        /* permissions */
        return nfsd4_encode_open_nfsace4(xdr);
}

static __be32
nfsd4_encode_nfs_space_limit4(struct xdr_stream *xdr, u64 filesize)
{
        /* limitby */
        if (xdr_stream_encode_u32(xdr, NFS4_LIMIT_SIZE) != XDR_UNIT)
                return nfserr_resource;
        /* filesize */
        return nfsd4_encode_uint64_t(xdr, filesize);
}

static __be32
nfsd4_encode_open_write_delegation4(struct xdr_stream *xdr,
                                    struct nfsd4_open *open)
{
        __be32 status;

        /* stateid */
        status = nfsd4_encode_stateid4(xdr, &open->op_delegate_stateid);
        if (status != nfs_ok)
                return status;
        /* recall */
        status = nfsd4_encode_bool(xdr, open->op_recall);
        if (status != nfs_ok)
                return status;
        /* space_limit */
        status = nfsd4_encode_nfs_space_limit4(xdr, 0);
        if (status != nfs_ok)
                return status;
        return nfsd4_encode_open_nfsace4(xdr);
}

static __be32
nfsd4_encode_open_none_delegation4(struct xdr_stream *xdr,
                                   struct nfsd4_open *open)
{
        __be32 status = nfs_ok;

        /* ond_why */
        if (xdr_stream_encode_u32(xdr, open->op_why_no_deleg) != XDR_UNIT)
                return nfserr_resource;
        switch (open->op_why_no_deleg) {
        case WND4_CONTENTION:
                /* ond_server_will_push_deleg */
                status = nfsd4_encode_bool(xdr, false);
                break;
        case WND4_RESOURCE:
                /* ond_server_will_signal_avail */
                status = nfsd4_encode_bool(xdr, false);
        }
        return status;
}

static __be32
nfsd4_encode_open_delegation4(struct xdr_stream *xdr, struct nfsd4_open *open)
{
        __be32 status;

        /* delegation_type */
        if (xdr_stream_encode_u32(xdr, open->op_delegate_type) != XDR_UNIT)
                return nfserr_resource;
        switch (open->op_delegate_type) {
        case OPEN_DELEGATE_NONE:
                status = nfs_ok;
                break;
        case OPEN_DELEGATE_READ:
        case OPEN_DELEGATE_READ_ATTRS_DELEG:
                /* read */
                status = nfsd4_encode_open_read_delegation4(xdr, open);
                break;
        case OPEN_DELEGATE_WRITE:
        case OPEN_DELEGATE_WRITE_ATTRS_DELEG:
                /* write */
                status = nfsd4_encode_open_write_delegation4(xdr, open);
                break;
        case OPEN_DELEGATE_NONE_EXT:
                /* od_whynone */
                status = nfsd4_encode_open_none_delegation4(xdr, open);
                break;
        default:
                status = nfserr_serverfault;
        }

        return status;
}

static __be32
nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_open *open = &u->open;
        struct xdr_stream *xdr = resp->xdr;

        /* stateid */
        nfserr = nfsd4_encode_stateid4(xdr, &open->op_stateid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* cinfo */
        nfserr = nfsd4_encode_change_info4(xdr, &open->op_cinfo);
        if (nfserr != nfs_ok)
                return nfserr;
        /* rflags */
        nfserr = nfsd4_encode_uint32_t(xdr, open->op_rflags);
        if (nfserr != nfs_ok)
                return nfserr;
        /* attrset */
        nfserr = nfsd4_encode_bitmap4(xdr, open->op_bmval[0],
                                      open->op_bmval[1], open->op_bmval[2]);
        if (nfserr != nfs_ok)
                return nfserr;
        /* delegation */
        return nfsd4_encode_open_delegation4(xdr, open);
}

static __be32
nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr,
                          union nfsd4_op_u *u)
{
        struct nfsd4_open_confirm *oc = &u->open_confirm;
        struct xdr_stream *xdr = resp->xdr;

        /* open_stateid */
        return nfsd4_encode_stateid4(xdr, &oc->oc_resp_stateid);
}

static __be32
nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr,
                            union nfsd4_op_u *u)
{
        struct nfsd4_open_downgrade *od = &u->open_downgrade;
        struct xdr_stream *xdr = resp->xdr;

        /* open_stateid */
        return nfsd4_encode_stateid4(xdr, &od->od_stateid);
}

/*
 * The operation of this function assumes that this is the only
 * READ operation in the COMPOUND. If there are multiple READs,
 * we use nfsd4_encode_readv().
 */
static __be32 nfsd4_encode_splice_read(
                                struct nfsd4_compoundres *resp,
                                struct nfsd4_read *read,
                                struct file *file, unsigned long maxcount)
{
        struct xdr_stream *xdr = resp->xdr;
        struct xdr_buf *buf = xdr->buf;
        int status, space_left;
        __be32 nfserr;

        /*
         * Splice read doesn't work if encoding has already wandered
         * into the XDR buf's page array.
         */
        if (unlikely(xdr->buf->page_len)) {
                WARN_ON_ONCE(1);
                return nfserr_serverfault;
        }

        /*
         * Make sure there is room at the end of buf->head for
         * svcxdr_encode_opaque_pages() to create a tail buffer
         * to XDR-pad the payload.
         */
        if (xdr->iov != xdr->buf->head || xdr->end - xdr->p < 1)
                return nfserr_resource;

        nfserr = nfsd_splice_read(read->rd_rqstp, read->rd_fhp,
                                  file, read->rd_offset, &maxcount,
                                  &read->rd_eof);
        read->rd_length = maxcount;
        if (nfserr)
                goto out_err;
        svcxdr_encode_opaque_pages(read->rd_rqstp, xdr, buf->pages,
                                   buf->page_base, maxcount);
        status = svc_encode_result_payload(read->rd_rqstp,
                                           buf->head[0].iov_len, maxcount);
        if (status) {
                nfserr = nfserrno(status);
                goto out_err;
        }

        /*
         * Prepare to encode subsequent operations.
         *
         * xdr_truncate_encode() is not safe to use after a successful
         * splice read has been done, so the following stream
         * manipulations are open-coded.
         */
        space_left = min_t(int, (void *)xdr->end - (void *)xdr->p,
                                buf->buflen - buf->len);
        buf->buflen = buf->len + space_left;
        xdr->end = (__be32 *)((void *)xdr->end + space_left);

        return nfs_ok;

out_err:
        /*
         * nfsd_splice_actor may have already messed with the
         * page length; reset it so as not to confuse
         * xdr_truncate_encode in our caller.
         */
        buf->page_len = 0;
        return nfserr;
}

static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
                                 struct nfsd4_read *read,
                                 unsigned long maxcount)
{
        struct xdr_stream *xdr = resp->xdr;
        unsigned int base = xdr->buf->page_len & ~PAGE_MASK;
        unsigned int starting_len = xdr->buf->len;
        __be32 zero = xdr_zero;
        __be32 nfserr;

        nfserr = nfsd_iter_read(resp->rqstp, read->rd_fhp, read->rd_nf,
                                read->rd_offset, &maxcount, base,
                                &read->rd_eof);
        read->rd_length = maxcount;
        if (nfserr)
                return nfserr;

        /*
         * svcxdr_encode_opaque_pages() is not used here because
         * we don't want to encode subsequent results in this
         * COMPOUND into the xdr->buf's tail, but rather those
         * results should follow the NFS READ payload in the
         * buf's pages.
         */
        if (xdr_reserve_space_vec(xdr, maxcount) < 0)
                return nfserr_resource;

        /*
         * Mark the buffer location of the NFS READ payload so that
         * direct placement-capable transports send only the
         * payload bytes out-of-band.
         */
        if (svc_encode_result_payload(resp->rqstp, starting_len, maxcount))
                return nfserr_io;

        write_bytes_to_xdr_buf(xdr->buf, starting_len + maxcount, &zero,
                               xdr_pad_size(maxcount));
        return nfs_ok;
}

static __be32
nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_compoundargs *argp = resp->rqstp->rq_argp;
        struct nfsd4_read *read = &u->read;
        struct xdr_stream *xdr = resp->xdr;
        bool splice_ok = argp->splice_ok;
        unsigned int eof_offset;
        unsigned long maxcount;
        __be32 wire_data[2];
        struct file *file;

        if (nfserr)
                return nfserr;

        eof_offset = xdr->buf->len;
        file = read->rd_nf->nf_file;

        /* Reserve space for the eof flag and byte count */
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT * 2))) {
                WARN_ON_ONCE(splice_ok);
                return nfserr_resource;
        }
        xdr_commit_encode(xdr);

        maxcount = min_t(unsigned long, read->rd_length,
                         (xdr->buf->buflen - xdr->buf->len));

        if (file->f_op->splice_read && splice_ok)
                nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
        else
                nfserr = nfsd4_encode_readv(resp, read, maxcount);
        if (nfserr) {
                xdr_truncate_encode(xdr, eof_offset);
                return nfserr;
        }

        wire_data[0] = read->rd_eof ? xdr_one : xdr_zero;
        wire_data[1] = cpu_to_be32(read->rd_length);
        write_bytes_to_xdr_buf(xdr->buf, eof_offset, &wire_data, XDR_UNIT * 2);
        return nfs_ok;
}

static __be32
nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr,
                      union nfsd4_op_u *u)
{
        struct nfsd4_readlink *readlink = &u->readlink;
        __be32 *p, wire_count, zero = xdr_zero;
        struct xdr_stream *xdr = resp->xdr;
        unsigned int length_offset;
        int maxcount, status;

        /* linktext4.count */
        length_offset = xdr->buf->len;
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT)))
                return nfserr_resource;

        /* linktext4.data */
        maxcount = PAGE_SIZE;
        p = xdr_reserve_space(xdr, maxcount);
        if (!p)
                return nfserr_resource;
        nfserr = nfsd_readlink(readlink->rl_rqstp, readlink->rl_fhp,
                                                (char *)p, &maxcount);
        if (nfserr == nfserr_isdir)
                nfserr = nfserr_inval;
        if (nfserr)
                goto out_err;
        status = svc_encode_result_payload(readlink->rl_rqstp, length_offset,
                                           maxcount);
        if (status) {
                nfserr = nfserrno(status);
                goto out_err;
        }

        wire_count = cpu_to_be32(maxcount);
        write_bytes_to_xdr_buf(xdr->buf, length_offset, &wire_count, XDR_UNIT);
        xdr_truncate_encode(xdr, length_offset + 4 + xdr_align_size(maxcount));
        write_bytes_to_xdr_buf(xdr->buf, length_offset + 4 + maxcount, &zero,
                               xdr_pad_size(maxcount));
        return nfs_ok;

out_err:
        xdr_truncate_encode(xdr, length_offset);
        return nfserr;
}

static __be32 nfsd4_encode_dirlist4(struct xdr_stream *xdr,
                                    struct nfsd4_readdir *readdir,
                                    u32 max_payload)
{
        int bytes_left, maxcount, starting_len = xdr->buf->len;
        loff_t offset;
        __be32 status;

        /*
         * Number of bytes left for directory entries allowing for the
         * final 8 bytes of the readdir and a following failed op.
         */
        bytes_left = xdr->buf->buflen - xdr->buf->len -
                COMPOUND_ERR_SLACK_SPACE - XDR_UNIT * 2;
        if (bytes_left < 0)
                return nfserr_resource;
        maxcount = min_t(u32, readdir->rd_maxcount, max_payload);

        /*
         * The RFC defines rd_maxcount as the size of the
         * READDIR4resok structure, which includes the verifier
         * and the 8 bytes encoded at the end of this function.
         */
        if (maxcount < XDR_UNIT * 4)
                return nfserr_toosmall;
        maxcount = min_t(int, maxcount - XDR_UNIT * 4, bytes_left);

        /* RFC 3530 14.2.24 allows us to ignore dircount when it's 0 */
        if (!readdir->rd_dircount)
                readdir->rd_dircount = max_payload;

        /* *entries */
        readdir->xdr = xdr;
        readdir->rd_maxcount = maxcount;
        readdir->common.err = 0;
        readdir->cookie_offset = 0;
        offset = readdir->rd_cookie;
        status = nfsd_readdir(readdir->rd_rqstp, readdir->rd_fhp, &offset,
                              &readdir->common, nfsd4_encode_entry4);
        if (status)
                return status;
        if (readdir->common.err == nfserr_toosmall &&
            xdr->buf->len == starting_len) {
                /* No entries were encoded. Which limit did we hit? */
                if (maxcount - XDR_UNIT * 4 < bytes_left)
                        /* It was the fault of rd_maxcount */
                        return nfserr_toosmall;
                /* We ran out of buffer space */
                return nfserr_resource;
        }
        /* Encode the final entry's cookie value */
        nfsd4_encode_entry4_nfs_cookie4(readdir, offset);
        /* No entries follow */
        if (xdr_stream_encode_item_absent(xdr) != XDR_UNIT)
                return nfserr_resource;

        /* eof */
        return nfsd4_encode_bool(xdr, readdir->common.err == nfserr_eof);
}

static __be32
nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr,
                     union nfsd4_op_u *u)
{
        struct nfsd4_readdir *readdir = &u->readdir;
        struct xdr_stream *xdr = resp->xdr;
        int starting_len = xdr->buf->len;

        /* cookieverf */
        nfserr = nfsd4_encode_verifier4(xdr, &readdir->rd_verf);
        if (nfserr != nfs_ok)
                return nfserr;

        /* reply */
        nfserr = nfsd4_encode_dirlist4(xdr, readdir, svc_max_payload(resp->rqstp));
        if (nfserr != nfs_ok)
                xdr_truncate_encode(xdr, starting_len);
        return nfserr;
}

static __be32
nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr,
                    union nfsd4_op_u *u)
{
        struct nfsd4_remove *remove = &u->remove;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_change_info4(xdr, &remove->rm_cinfo);
}

static __be32
nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr,
                    union nfsd4_op_u *u)
{
        struct nfsd4_rename *rename = &u->rename;
        struct xdr_stream *xdr = resp->xdr;

        nfserr = nfsd4_encode_change_info4(xdr, &rename->rn_sinfo);
        if (nfserr)
                return nfserr;
        return nfsd4_encode_change_info4(xdr, &rename->rn_tinfo);
}

static __be32
nfsd4_encode_rpcsec_gss_info(struct xdr_stream *xdr,
                             struct rpcsec_gss_info *info)
{
        __be32 status;

        /* oid */
        if (xdr_stream_encode_opaque(xdr, info->oid.data, info->oid.len) < 0)
                return nfserr_resource;
        /* qop */
        status = nfsd4_encode_qop4(xdr, info->qop);
        if (status != nfs_ok)
                return status;
        /* service */
        if (xdr_stream_encode_u32(xdr, info->service) != XDR_UNIT)
                return nfserr_resource;

        return nfs_ok;
}

static __be32
nfsd4_encode_secinfo4(struct xdr_stream *xdr, rpc_authflavor_t pf,
                      u32 *supported)
{
        struct rpcsec_gss_info info;
        __be32 status;

        if (rpcauth_get_gssinfo(pf, &info) == 0) {
                (*supported)++;

                /* flavor */
                status = nfsd4_encode_uint32_t(xdr, RPC_AUTH_GSS);
                if (status != nfs_ok)
                        return status;
                /* flavor_info */
                status = nfsd4_encode_rpcsec_gss_info(xdr, &info);
                if (status != nfs_ok)
                        return status;
        } else if (pf < RPC_AUTH_MAXFLAVOR) {
                (*supported)++;

                /* flavor */
                status = nfsd4_encode_uint32_t(xdr, pf);
                if (status != nfs_ok)
                        return status;
        }
        return nfs_ok;
}

static __be32
nfsd4_encode_SECINFO4resok(struct xdr_stream *xdr, struct svc_export *exp)
{
        u32 i, nflavs, supported;
        struct exp_flavor_info *flavs;
        struct exp_flavor_info def_flavs[2];
        unsigned int count_offset;
        __be32 status, wire_count;

        if (exp->ex_nflavors) {
                flavs = exp->ex_flavors;
                nflavs = exp->ex_nflavors;
        } else { /* Handling of some defaults in absence of real secinfo: */
                flavs = def_flavs;
                if (exp->ex_client->flavour->flavour == RPC_AUTH_UNIX) {
                        nflavs = 2;
                        flavs[0].pseudoflavor = RPC_AUTH_UNIX;
                        flavs[1].pseudoflavor = RPC_AUTH_NULL;
                } else if (exp->ex_client->flavour->flavour == RPC_AUTH_GSS) {
                        nflavs = 1;
                        flavs[0].pseudoflavor
                                        = svcauth_gss_flavor(exp->ex_client);
                } else {
                        nflavs = 1;
                        flavs[0].pseudoflavor
                                        = exp->ex_client->flavour->flavour;
                }
        }

        count_offset = xdr->buf->len;
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT)))
                return nfserr_resource;

        for (i = 0, supported = 0; i < nflavs; i++) {
                status = nfsd4_encode_secinfo4(xdr, flavs[i].pseudoflavor,
                                               &supported);
                if (status != nfs_ok)
                        return status;
        }

        wire_count = cpu_to_be32(supported);
        write_bytes_to_xdr_buf(xdr->buf, count_offset, &wire_count,
                               XDR_UNIT);
        return 0;
}

static __be32
nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
                     union nfsd4_op_u *u)
{
        struct nfsd4_secinfo *secinfo = &u->secinfo;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_SECINFO4resok(xdr, secinfo->si_exp);
}

static __be32
nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
                     union nfsd4_op_u *u)
{
        struct nfsd4_secinfo_no_name *secinfo = &u->secinfo_no_name;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_SECINFO4resok(xdr, secinfo->sin_exp);
}

static __be32
nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr,
                     union nfsd4_op_u *u)
{
        struct nfsd4_setattr *setattr = &u->setattr;
        __be32 status;

        switch (nfserr) {
        case nfs_ok:
                /* attrsset */
                status = nfsd4_encode_bitmap4(resp->xdr, setattr->sa_bmval[0],
                                              setattr->sa_bmval[1],
                                              setattr->sa_bmval[2]);
                break;
        default:
                /* attrsset */
                status = nfsd4_encode_bitmap4(resp->xdr, 0, 0, 0);
        }
        return status != nfs_ok ? status : nfserr;
}

static __be32
nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr,
                         union nfsd4_op_u *u)
{
        struct nfsd4_setclientid *scd = &u->setclientid;
        struct xdr_stream *xdr = resp->xdr;

        if (!nfserr) {
                nfserr = nfsd4_encode_clientid4(xdr, &scd->se_clientid);
                if (nfserr != nfs_ok)
                        goto out;
                nfserr = nfsd4_encode_verifier4(xdr, &scd->se_confirm);
        } else if (nfserr == nfserr_clid_inuse) {
                /* empty network id */
                if (xdr_stream_encode_u32(xdr, 0) < 0) {
                        nfserr = nfserr_resource;
                        goto out;
                }
                /* empty universal address */
                if (xdr_stream_encode_u32(xdr, 0) < 0) {
                        nfserr = nfserr_resource;
                        goto out;
                }
        }
out:
        return nfserr;
}

static __be32
nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr,
                   union nfsd4_op_u *u)
{
        struct nfsd4_write *write = &u->write;
        struct xdr_stream *xdr = resp->xdr;

        /* count */
        nfserr = nfsd4_encode_count4(xdr, write->wr_bytes_written);
        if (nfserr)
                return nfserr;
        /* committed */
        if (xdr_stream_encode_u32(xdr, write->wr_how_written) != XDR_UNIT)
                return nfserr_resource;
        /* writeverf */
        return nfsd4_encode_verifier4(xdr, &write->wr_verifier);
}

static __be32
nfsd4_encode_state_protect_ops4(struct xdr_stream *xdr,
                                struct nfsd4_exchange_id *exid)
{
        __be32 status;

        /* spo_must_enforce */
        status = nfsd4_encode_bitmap4(xdr, exid->spo_must_enforce[0],
                                      exid->spo_must_enforce[1],
                                      exid->spo_must_enforce[2]);
        if (status != nfs_ok)
                return status;
        /* spo_must_allow */
        return nfsd4_encode_bitmap4(xdr, exid->spo_must_allow[0],
                                    exid->spo_must_allow[1],
                                    exid->spo_must_allow[2]);
}

static __be32
nfsd4_encode_state_protect4_r(struct xdr_stream *xdr, struct nfsd4_exchange_id *exid)
{
        __be32 status;

        if (xdr_stream_encode_u32(xdr, exid->spa_how) != XDR_UNIT)
                return nfserr_resource;
        switch (exid->spa_how) {
        case SP4_NONE:
                status = nfs_ok;
                break;
        case SP4_MACH_CRED:
                /* spr_mach_ops */
                status = nfsd4_encode_state_protect_ops4(xdr, exid);
                break;
        default:
                status = nfserr_serverfault;
        }
        return status;
}

static __be32
nfsd4_encode_server_owner4(struct xdr_stream *xdr, struct svc_rqst *rqstp)
{
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
        __be32 status;

        /* so_minor_id */
        status = nfsd4_encode_uint64_t(xdr, 0);
        if (status != nfs_ok)
                return status;
        /* so_major_id */
        return nfsd4_encode_opaque(xdr, nn->nfsd_name, strlen(nn->nfsd_name));
}

static __be32
nfsd4_encode_nfs_impl_id4(struct xdr_stream *xdr, struct nfsd4_exchange_id *exid)
{
        __be32 status;

        /* nii_domain */
        status = nfsd4_encode_opaque(xdr, exid->nii_domain.data,
                                     exid->nii_domain.len);
        if (status != nfs_ok)
                return status;
        /* nii_name */
        status = nfsd4_encode_opaque(xdr, exid->nii_name.data,
                                     exid->nii_name.len);
        if (status != nfs_ok)
                return status;
        /* nii_time */
        return nfsd4_encode_nfstime4(xdr, &exid->nii_time);
}

static __be32
nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
                         union nfsd4_op_u *u)
{
        struct nfsd_net *nn = net_generic(SVC_NET(resp->rqstp), nfsd_net_id);
        struct nfsd4_exchange_id *exid = &u->exchange_id;
        struct xdr_stream *xdr = resp->xdr;

        /* eir_clientid */
        nfserr = nfsd4_encode_clientid4(xdr, &exid->clientid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_sequenceid */
        nfserr = nfsd4_encode_sequenceid4(xdr, exid->seqid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_flags */
        nfserr = nfsd4_encode_uint32_t(xdr, exid->flags);
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_state_protect */
        nfserr = nfsd4_encode_state_protect4_r(xdr, exid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_server_owner */
        nfserr = nfsd4_encode_server_owner4(xdr, resp->rqstp);
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_server_scope */
        nfserr = nfsd4_encode_opaque(xdr, nn->nfsd_name,
                                     strlen(nn->nfsd_name));
        if (nfserr != nfs_ok)
                return nfserr;
        /* eir_server_impl_id<1> */
        if (xdr_stream_encode_u32(xdr, 1) != XDR_UNIT)
                return nfserr_resource;
        nfserr = nfsd4_encode_nfs_impl_id4(xdr, exid);
        if (nfserr != nfs_ok)
                return nfserr;

        return nfs_ok;
}

static __be32
nfsd4_encode_channel_attrs4(struct xdr_stream *xdr,
                            const struct nfsd4_channel_attrs *attrs)
{
        __be32 status;

        /* ca_headerpadsize */
        status = nfsd4_encode_count4(xdr, 0);
        if (status != nfs_ok)
                return status;
        /* ca_maxrequestsize */
        status = nfsd4_encode_count4(xdr, attrs->maxreq_sz);
        if (status != nfs_ok)
                return status;
        /* ca_maxresponsesize */
        status = nfsd4_encode_count4(xdr, attrs->maxresp_sz);
        if (status != nfs_ok)
                return status;
        /* ca_maxresponsesize_cached */
        status = nfsd4_encode_count4(xdr, attrs->maxresp_cached);
        if (status != nfs_ok)
                return status;
        /* ca_maxoperations */
        status = nfsd4_encode_count4(xdr, attrs->maxops);
        if (status != nfs_ok)
                return status;
        /* ca_maxrequests */
        status = nfsd4_encode_count4(xdr, attrs->maxreqs);
        if (status != nfs_ok)
                return status;
        /* ca_rdma_ird<1> */
        if (xdr_stream_encode_u32(xdr, attrs->nr_rdma_attrs) != XDR_UNIT)
                return nfserr_resource;
        if (attrs->nr_rdma_attrs)
                return nfsd4_encode_uint32_t(xdr, attrs->rdma_attrs);
        return nfs_ok;
}

static __be32
nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
                            union nfsd4_op_u *u)
{
        struct nfsd4_create_session *sess = &u->create_session;
        struct xdr_stream *xdr = resp->xdr;

        /* csr_sessionid */
        nfserr = nfsd4_encode_sessionid4(xdr, &sess->sessionid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* csr_sequence */
        nfserr = nfsd4_encode_sequenceid4(xdr, sess->seqid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* csr_flags */
        nfserr = nfsd4_encode_uint32_t(xdr, sess->flags);
        if (nfserr != nfs_ok)
                return nfserr;
        /* csr_fore_chan_attrs */
        nfserr = nfsd4_encode_channel_attrs4(xdr, &sess->fore_channel);
        if (nfserr != nfs_ok)
                return nfserr;
        /* csr_back_chan_attrs */
        return nfsd4_encode_channel_attrs4(xdr, &sess->back_channel);
}

static __be32
nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
                      union nfsd4_op_u *u)
{
        struct nfsd4_sequence *seq = &u->sequence;
        struct xdr_stream *xdr = resp->xdr;

        /* sr_sessionid */
        nfserr = nfsd4_encode_sessionid4(xdr, &seq->sessionid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* sr_sequenceid */
        nfserr = nfsd4_encode_sequenceid4(xdr, seq->seqid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* sr_slotid */
        nfserr = nfsd4_encode_slotid4(xdr, seq->slotid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* Note slotid's are numbered from zero: */
        /* sr_highest_slotid */
        nfserr = nfsd4_encode_slotid4(xdr, seq->maxslots_response - 1);
        if (nfserr != nfs_ok)
                return nfserr;
        /* sr_target_highest_slotid */
        nfserr = nfsd4_encode_slotid4(xdr, seq->target_maxslots - 1);
        if (nfserr != nfs_ok)
                return nfserr;
        /* sr_status_flags */
        nfserr = nfsd4_encode_uint32_t(xdr, seq->status_flags);
        if (nfserr != nfs_ok)
                return nfserr;

        resp->cstate.data_offset = xdr->buf->len; /* DRC cache data pointer */
        return nfs_ok;
}

static __be32
nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
                          union nfsd4_op_u *u)
{
        struct nfsd4_test_stateid *test_stateid = &u->test_stateid;
        struct nfsd4_test_stateid_id *stateid, *next;
        struct xdr_stream *xdr = resp->xdr;

        /* tsr_status_codes<> */
        if (xdr_stream_encode_u32(xdr, test_stateid->ts_num_ids) != XDR_UNIT)
                return nfserr_resource;
        list_for_each_entry_safe(stateid, next,
                                 &test_stateid->ts_stateid_list, ts_id_list) {
                if (xdr_stream_encode_be32(xdr, stateid->ts_id_status) != XDR_UNIT)
                        return nfserr_resource;
        }
        return nfs_ok;
}

static __be32
nfsd4_encode_get_dir_delegation(struct nfsd4_compoundres *resp, __be32 nfserr,
                                union nfsd4_op_u *u)
{
        struct nfsd4_get_dir_delegation *gdd = &u->get_dir_delegation;
        struct xdr_stream *xdr = resp->xdr;
        __be32 status = nfserr_resource;

        switch(gdd->gddrnf_status) {
        case GDD4_OK:
                if (xdr_stream_encode_u32(xdr, GDD4_OK) != XDR_UNIT)
                        break;
                status = nfsd4_encode_verifier4(xdr, &gdd->gddr_cookieverf);
                if (status)
                        break;
                status = nfsd4_encode_stateid4(xdr, &gdd->gddr_stateid);
                if (status)
                        break;
                status = nfsd4_encode_bitmap4(xdr, gdd->gddr_notification[0], 0, 0);
                if (status)
                        break;
                status = nfsd4_encode_bitmap4(xdr, gdd->gddr_child_attributes[0],
                                                   gdd->gddr_child_attributes[1],
                                                   gdd->gddr_child_attributes[2]);
                if (status)
                        break;
                status = nfsd4_encode_bitmap4(xdr, gdd->gddr_dir_attributes[0],
                                                   gdd->gddr_dir_attributes[1],
                                                   gdd->gddr_dir_attributes[2]);
                break;
        default:
                pr_warn("nfsd: bad gddrnf_status (%u)\n", gdd->gddrnf_status);
                gdd->gddrnf_will_signal_deleg_avail = 0;
                fallthrough;
        case GDD4_UNAVAIL:
                if (xdr_stream_encode_u32(xdr, GDD4_UNAVAIL) != XDR_UNIT)
                        break;
                status = nfsd4_encode_bool(xdr, gdd->gddrnf_will_signal_deleg_avail);
                break;
        }
        return status;
}

#ifdef CONFIG_NFSD_PNFS
static __be32
nfsd4_encode_device_addr4(struct xdr_stream *xdr,
                          const struct nfsd4_getdeviceinfo *gdev)
{
        u32 needed_len, starting_len = xdr->buf->len;
        const struct nfsd4_layout_ops *ops;
        __be32 status;

        /* da_layout_type */
        if (xdr_stream_encode_u32(xdr, gdev->gd_layout_type) != XDR_UNIT)
                return nfserr_resource;
        /* da_addr_body */
        ops = nfsd4_layout_ops[gdev->gd_layout_type];
        status = ops->encode_getdeviceinfo(xdr, gdev);
        if (status != nfs_ok) {
                /*
                 * Don't burden the layout drivers with enforcing
                 * gd_maxcount. Just tell the client to come back
                 * with a bigger buffer if it's not enough.
                 */
                if (xdr->buf->len + XDR_UNIT > gdev->gd_maxcount)
                        goto toosmall;
                return status;
        }

        return nfs_ok;

toosmall:
        needed_len = xdr->buf->len + XDR_UNIT;  /* notifications */
        xdr_truncate_encode(xdr, starting_len);

        status = nfsd4_encode_count4(xdr, needed_len);
        if (status != nfs_ok)
                return status;
        return nfserr_toosmall;
}

static __be32
nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
                union nfsd4_op_u *u)
{
        struct nfsd4_getdeviceinfo *gdev = &u->getdeviceinfo;
        struct xdr_stream *xdr = resp->xdr;

        /* gdir_device_addr */
        nfserr = nfsd4_encode_device_addr4(xdr, gdev);
        if (nfserr)
                return nfserr;
        /* gdir_notification */
        return nfsd4_encode_bitmap4(xdr, gdev->gd_notify_types, 0, 0);
}

static __be32
nfsd4_encode_layout4(struct xdr_stream *xdr, const struct nfsd4_layoutget *lgp)
{
        const struct nfsd4_layout_ops *ops = nfsd4_layout_ops[lgp->lg_layout_type];
        __be32 status;

        /* lo_offset */
        status = nfsd4_encode_offset4(xdr, lgp->lg_seg.offset);
        if (status != nfs_ok)
                return status;
        /* lo_length */
        status = nfsd4_encode_length4(xdr, lgp->lg_seg.length);
        if (status != nfs_ok)
                return status;
        /* lo_iomode */
        if (xdr_stream_encode_u32(xdr, lgp->lg_seg.iomode) != XDR_UNIT)
                return nfserr_resource;
        /* lo_content */
        if (xdr_stream_encode_u32(xdr, lgp->lg_layout_type) != XDR_UNIT)
                return nfserr_resource;
        return ops->encode_layoutget(xdr, lgp);
}

static __be32
nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr,
                union nfsd4_op_u *u)
{
        struct nfsd4_layoutget *lgp = &u->layoutget;
        struct xdr_stream *xdr = resp->xdr;

        /* logr_return_on_close */
        nfserr = nfsd4_encode_bool(xdr, true);
        if (nfserr != nfs_ok)
                return nfserr;
        /* logr_stateid */
        nfserr = nfsd4_encode_stateid4(xdr, &lgp->lg_sid);
        if (nfserr != nfs_ok)
                return nfserr;
        /* logr_layout<> */
        if (xdr_stream_encode_u32(xdr, 1) != XDR_UNIT)
                return nfserr_resource;
        return nfsd4_encode_layout4(xdr, lgp);
}

static __be32
nfsd4_encode_layoutcommit(struct nfsd4_compoundres *resp, __be32 nfserr,
                          union nfsd4_op_u *u)
{
        struct nfsd4_layoutcommit *lcp = &u->layoutcommit;
        struct xdr_stream *xdr = resp->xdr;

        /* ns_sizechanged */
        nfserr = nfsd4_encode_bool(xdr, lcp->lc_size_chg);
        if (nfserr != nfs_ok)
                return nfserr;
        if (lcp->lc_size_chg)
                /* ns_size */
                return nfsd4_encode_length4(xdr, lcp->lc_newsize);
        return nfs_ok;
}

static __be32
nfsd4_encode_layoutreturn(struct nfsd4_compoundres *resp, __be32 nfserr,
                union nfsd4_op_u *u)
{
        struct nfsd4_layoutreturn *lrp = &u->layoutreturn;
        struct xdr_stream *xdr = resp->xdr;

        /* lrs_present */
        nfserr = nfsd4_encode_bool(xdr, lrp->lrs_present);
        if (nfserr != nfs_ok)
                return nfserr;
        if (lrp->lrs_present)
                /* lrs_stateid */
                return nfsd4_encode_stateid4(xdr, &lrp->lr_sid);
        return nfs_ok;
}
#endif /* CONFIG_NFSD_PNFS */

static __be32
nfsd4_encode_write_response4(struct xdr_stream *xdr,
                             const struct nfsd4_copy *copy)
{
        const struct nfsd42_write_res *write = &copy->cp_res;
        u32 count = nfsd4_copy_is_sync(copy) ? 0 : 1;
        __be32 status;

        /* wr_callback_id<1> */
        if (xdr_stream_encode_u32(xdr, count) != XDR_UNIT)
                return nfserr_resource;
        if (count) {
                status = nfsd4_encode_stateid4(xdr, &write->cb_stateid);
                if (status != nfs_ok)
                        return status;
        }

        /* wr_count */
        status = nfsd4_encode_length4(xdr, write->wr_bytes_written);
        if (status != nfs_ok)
                return status;
        /* wr_committed */
        if (xdr_stream_encode_u32(xdr, write->wr_stable_how) != XDR_UNIT)
                return nfserr_resource;
        /* wr_writeverf */
        return nfsd4_encode_verifier4(xdr, &write->wr_verifier);
}

static __be32 nfsd4_encode_copy_requirements4(struct xdr_stream *xdr,
                                              const struct nfsd4_copy *copy)
{
        __be32 status;

        /* cr_consecutive */
        status = nfsd4_encode_bool(xdr, true);
        if (status != nfs_ok)
                return status;
        /* cr_synchronous */
        return nfsd4_encode_bool(xdr, nfsd4_copy_is_sync(copy));
}

static __be32
nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_copy *copy = &u->copy;

        nfserr = nfsd4_encode_write_response4(resp->xdr, copy);
        if (nfserr != nfs_ok)
                return nfserr;
        return nfsd4_encode_copy_requirements4(resp->xdr, copy);
}

static __be32
nfsd4_encode_netloc4(struct xdr_stream *xdr, const struct nl4_server *ns)
{
        __be32 status;

        if (xdr_stream_encode_u32(xdr, ns->nl4_type) != XDR_UNIT)
                return nfserr_resource;
        switch (ns->nl4_type) {
        case NL4_NETADDR:
                /* nl_addr */
                status = nfsd4_encode_netaddr4(xdr, &ns->u.nl4_addr);
                break;
        default:
                status = nfserr_serverfault;
        }
        return status;
}

static __be32
nfsd4_encode_copy_notify(struct nfsd4_compoundres *resp, __be32 nfserr,
                         union nfsd4_op_u *u)
{
        struct nfsd4_copy_notify *cn = &u->copy_notify;
        struct xdr_stream *xdr = resp->xdr;

        /* cnr_lease_time */
        nfserr = nfsd4_encode_nfstime4(xdr, &cn->cpn_lease_time);
        if (nfserr)
                return nfserr;
        /* cnr_stateid */
        nfserr = nfsd4_encode_stateid4(xdr, &cn->cpn_cnr_stateid);
        if (nfserr)
                return nfserr;
        /* cnr_source_server<> */
        if (xdr_stream_encode_u32(xdr, 1) != XDR_UNIT)
                return nfserr_resource;
        return nfsd4_encode_netloc4(xdr, cn->cpn_src);
}

static __be32
nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
                            union nfsd4_op_u *u)
{
        struct nfsd4_offload_status *os = &u->offload_status;
        struct xdr_stream *xdr = resp->xdr;

        /* osr_count */
        nfserr = nfsd4_encode_length4(xdr, os->count);
        if (nfserr != nfs_ok)
                return nfserr;
        /* osr_complete<1> */
        if (os->completed) {
                if (xdr_stream_encode_u32(xdr, 1) != XDR_UNIT)
                        return nfserr_resource;
                if (xdr_stream_encode_be32(xdr, os->status) != XDR_UNIT)
                        return nfserr_resource;
        } else if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
                return nfserr_resource;
        return nfs_ok;
}

static __be32
nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
                            struct nfsd4_read *read)
{
        struct nfsd4_compoundargs *argp = resp->rqstp->rq_argp;
        struct file *file = read->rd_nf->nf_file;
        struct xdr_stream *xdr = resp->xdr;
        bool splice_ok = argp->splice_ok;
        unsigned int offset_offset;
        __be32 nfserr, wire_count;
        unsigned long maxcount;
        __be64 wire_offset;

        if (xdr_stream_encode_u32(xdr, NFS4_CONTENT_DATA) != XDR_UNIT)
                return nfserr_io;

        offset_offset = xdr->buf->len;

        /* Reserve space for the byte offset and count */
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT * 3)))
                return nfserr_io;
        xdr_commit_encode(xdr);

        maxcount = min_t(unsigned long, read->rd_length,
                         (xdr->buf->buflen - xdr->buf->len));

        if (file->f_op->splice_read && splice_ok)
                nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
        else
                nfserr = nfsd4_encode_readv(resp, read, maxcount);
        if (nfserr)
                return nfserr;

        wire_offset = cpu_to_be64(read->rd_offset);
        write_bytes_to_xdr_buf(xdr->buf, offset_offset, &wire_offset,
                               XDR_UNIT * 2);
        wire_count = cpu_to_be32(read->rd_length);
        write_bytes_to_xdr_buf(xdr->buf, offset_offset + XDR_UNIT * 2,
                               &wire_count, XDR_UNIT);
        return nfs_ok;
}

static __be32
nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
                       union nfsd4_op_u *u)
{
        struct nfsd4_read *read = &u->read;
        struct file *file = read->rd_nf->nf_file;
        struct xdr_stream *xdr = resp->xdr;
        unsigned int eof_offset;
        __be32 wire_data[2];
        u32 segments = 0;

        if (nfserr)
                return nfserr;

        eof_offset = xdr->buf->len;

        /* Reserve space for the eof flag and segment count */
        if (unlikely(!xdr_reserve_space(xdr, XDR_UNIT * 2)))
                return nfserr_io;
        xdr_commit_encode(xdr);

        read->rd_eof = read->rd_offset >= i_size_read(file_inode(file));
        if (read->rd_eof)
                goto out;

        nfserr = nfsd4_encode_read_plus_data(resp, read);
        if (nfserr) {
                xdr_truncate_encode(xdr, eof_offset);
                return nfserr;
        }

        segments++;

out:
        wire_data[0] = read->rd_eof ? xdr_one : xdr_zero;
        wire_data[1] = cpu_to_be32(segments);
        write_bytes_to_xdr_buf(xdr->buf, eof_offset, &wire_data, XDR_UNIT * 2);
        return nfserr;
}

static __be32
nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *u)
{
        struct nfsd4_seek *seek = &u->seek;
        struct xdr_stream *xdr = resp->xdr;

        /* sr_eof */
        nfserr = nfsd4_encode_bool(xdr, seek->seek_eof);
        if (nfserr != nfs_ok)
                return nfserr;
        /* sr_offset */
        return nfsd4_encode_offset4(xdr, seek->seek_pos);
}

static __be32
nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr,
                  union nfsd4_op_u *p)
{
        return nfserr;
}

/*
 * Encode kmalloc-ed buffer in to XDR stream.
 */
static __be32
nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
{
        u32 cplen;
        __be32 *p;

        cplen = min_t(unsigned long, buflen,
                      ((void *)xdr->end - (void *)xdr->p));
        p = xdr_reserve_space(xdr, cplen);
        if (!p)
                return nfserr_resource;

        memcpy(p, buf, cplen);
        buf += cplen;
        buflen -= cplen;

        while (buflen) {
                cplen = min_t(u32, buflen, PAGE_SIZE);
                p = xdr_reserve_space(xdr, cplen);
                if (!p)
                        return nfserr_resource;

                memcpy(p, buf, cplen);

                if (cplen < PAGE_SIZE) {
                        /*
                         * We're done, with a length that wasn't page
                         * aligned, so possibly not word aligned. Pad
                         * any trailing bytes with 0.
                         */
                        xdr_encode_opaque_fixed(p, NULL, cplen);
                        break;
                }

                buflen -= PAGE_SIZE;
                buf += PAGE_SIZE;
        }

        return 0;
}

static __be32
nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
                      union nfsd4_op_u *u)
{
        struct nfsd4_getxattr *getxattr = &u->getxattr;
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p, err;

        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;

        *p = cpu_to_be32(getxattr->getxa_len);

        if (getxattr->getxa_len == 0)
                return 0;

        err = nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
                                    getxattr->getxa_len);

        kvfree(getxattr->getxa_buf);

        return err;
}

static __be32
nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
                      union nfsd4_op_u *u)
{
        struct nfsd4_setxattr *setxattr = &u->setxattr;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_change_info4(xdr, &setxattr->setxa_cinfo);
}

/*
 * See if there are cookie values that can be rejected outright.
 */
static __be32
nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
                                u32 *offsetp)
{
        u64 cookie = listxattrs->lsxa_cookie;

        /*
         * If the cookie is larger than the maximum number we can fit
         * in the buffer we just got back from vfs_listxattr, it's invalid.
         */
        if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
                return nfserr_badcookie;

        *offsetp = (u32)cookie;
        return 0;
}

static __be32
nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
                        union nfsd4_op_u *u)
{
        struct nfsd4_listxattrs *listxattrs = &u->listxattrs;
        struct xdr_stream *xdr = resp->xdr;
        u32 cookie_offset, count_offset, eof;
        u32 left, xdrleft, slen, count;
        u32 xdrlen, offset;
        u64 cookie;
        char *sp;
        __be32 status, tmp;
        __be64 wire_cookie;
        __be32 *p;
        u32 nuser;

        eof = 1;

        status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
        if (status)
                goto out;

        /*
         * Reserve space for the cookie and the name array count. Record
         * the offsets to save them later.
         */
        cookie_offset = xdr->buf->len;
        count_offset = cookie_offset + 8;
        p = xdr_reserve_space(xdr, XDR_UNIT * 3);
        if (!p) {
                status = nfserr_resource;
                goto out;
        }

        count = 0;
        left = listxattrs->lsxa_len;
        sp = listxattrs->lsxa_buf;
        nuser = 0;

        /* Bytes left is maxcount - 8 (cookie) - 4 (array count) */
        xdrleft = listxattrs->lsxa_maxcount - XDR_UNIT * 3;

        while (left > 0 && xdrleft > 0) {
                slen = strlen(sp);

                /*
                 * Check if this is a "user." attribute, skip it if not.
                 */
                if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
                        goto contloop;

                slen -= XATTR_USER_PREFIX_LEN;
                xdrlen = 4 + ((slen + 3) & ~3);
                /* Check if both entry and eof can fit in the XDR buffer */
                if (xdrlen + XDR_UNIT > xdrleft) {
                        if (count == 0) {
                                /*
                                 * Can't even fit the first attribute name.
                                 */
                                status = nfserr_toosmall;
                                goto out;
                        }
                        eof = 0;
                        goto wreof;
                }

                left -= XATTR_USER_PREFIX_LEN;
                sp += XATTR_USER_PREFIX_LEN;
                if (nuser++ < offset)
                        goto contloop;


                p = xdr_reserve_space(xdr, xdrlen);
                if (!p) {
                        status = nfserr_resource;
                        goto out;
                }

                xdr_encode_opaque(p, sp, slen);

                xdrleft -= xdrlen;
                count++;
contloop:
                sp += slen + 1;
                left -= slen + 1;
        }

        /*
         * If there were user attributes to copy, but we didn't copy
         * any, the offset was too large (e.g. the cookie was invalid).
         */
        if (nuser > 0 && count == 0) {
                status = nfserr_badcookie;
                goto out;
        }

wreof:
        p = xdr_reserve_space(xdr, 4);
        if (!p) {
                status = nfserr_resource;
                goto out;
        }
        *p = cpu_to_be32(eof);

        cookie = offset + count;

        wire_cookie = cpu_to_be64(cookie);
        write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &wire_cookie, 8);
        tmp = cpu_to_be32(count);
        write_bytes_to_xdr_buf(xdr->buf, count_offset, &tmp, 4);
out:
        if (listxattrs->lsxa_len)
                kvfree(listxattrs->lsxa_buf);
        return status;
}

static __be32
nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
                         union nfsd4_op_u *u)
{
        struct nfsd4_removexattr *removexattr = &u->removexattr;
        struct xdr_stream *xdr = resp->xdr;

        return nfsd4_encode_change_info4(xdr, &removexattr->rmxa_cinfo);
}

typedef __be32(*nfsd4_enc)(struct nfsd4_compoundres *, __be32, union nfsd4_op_u *u);

/*
 * Note: nfsd4_enc_ops vector is shared for v4.0 and v4.1
 * since we don't need to filter out obsolete ops as this is
 * done in the decoding phase.
 */
static const nfsd4_enc nfsd4_enc_ops[] = {
        [OP_ACCESS]             = nfsd4_encode_access,
        [OP_CLOSE]              = nfsd4_encode_close,
        [OP_COMMIT]             = nfsd4_encode_commit,
        [OP_CREATE]             = nfsd4_encode_create,
        [OP_DELEGPURGE]         = nfsd4_encode_noop,
        [OP_DELEGRETURN]        = nfsd4_encode_noop,
        [OP_GETATTR]            = nfsd4_encode_getattr,
        [OP_GETFH]              = nfsd4_encode_getfh,
        [OP_LINK]               = nfsd4_encode_link,
        [OP_LOCK]               = nfsd4_encode_lock,
        [OP_LOCKT]              = nfsd4_encode_lockt,
        [OP_LOCKU]              = nfsd4_encode_locku,
        [OP_LOOKUP]             = nfsd4_encode_noop,
        [OP_LOOKUPP]            = nfsd4_encode_noop,
        [OP_NVERIFY]            = nfsd4_encode_noop,
        [OP_OPEN]               = nfsd4_encode_open,
        [OP_OPENATTR]           = nfsd4_encode_noop,
        [OP_OPEN_CONFIRM]       = nfsd4_encode_open_confirm,
        [OP_OPEN_DOWNGRADE]     = nfsd4_encode_open_downgrade,
        [OP_PUTFH]              = nfsd4_encode_noop,
        [OP_PUTPUBFH]           = nfsd4_encode_noop,
        [OP_PUTROOTFH]          = nfsd4_encode_noop,
        [OP_READ]               = nfsd4_encode_read,
        [OP_READDIR]            = nfsd4_encode_readdir,
        [OP_READLINK]           = nfsd4_encode_readlink,
        [OP_REMOVE]             = nfsd4_encode_remove,
        [OP_RENAME]             = nfsd4_encode_rename,
        [OP_RENEW]              = nfsd4_encode_noop,
        [OP_RESTOREFH]          = nfsd4_encode_noop,
        [OP_SAVEFH]             = nfsd4_encode_noop,
        [OP_SECINFO]            = nfsd4_encode_secinfo,
        [OP_SETATTR]            = nfsd4_encode_setattr,
        [OP_SETCLIENTID]        = nfsd4_encode_setclientid,
        [OP_SETCLIENTID_CONFIRM] = nfsd4_encode_noop,
        [OP_VERIFY]             = nfsd4_encode_noop,
        [OP_WRITE]              = nfsd4_encode_write,
        [OP_RELEASE_LOCKOWNER]  = nfsd4_encode_noop,

        /* NFSv4.1 operations */
        [OP_BACKCHANNEL_CTL]    = nfsd4_encode_noop,
        [OP_BIND_CONN_TO_SESSION] = nfsd4_encode_bind_conn_to_session,
        [OP_EXCHANGE_ID]        = nfsd4_encode_exchange_id,
        [OP_CREATE_SESSION]     = nfsd4_encode_create_session,
        [OP_DESTROY_SESSION]    = nfsd4_encode_noop,
        [OP_FREE_STATEID]       = nfsd4_encode_noop,
        [OP_GET_DIR_DELEGATION] = nfsd4_encode_get_dir_delegation,
#ifdef CONFIG_NFSD_PNFS
        [OP_GETDEVICEINFO]      = nfsd4_encode_getdeviceinfo,
        [OP_GETDEVICELIST]      = nfsd4_encode_noop,
        [OP_LAYOUTCOMMIT]       = nfsd4_encode_layoutcommit,
        [OP_LAYOUTGET]          = nfsd4_encode_layoutget,
        [OP_LAYOUTRETURN]       = nfsd4_encode_layoutreturn,
#else
        [OP_GETDEVICEINFO]      = nfsd4_encode_noop,
        [OP_GETDEVICELIST]      = nfsd4_encode_noop,
        [OP_LAYOUTCOMMIT]       = nfsd4_encode_noop,
        [OP_LAYOUTGET]          = nfsd4_encode_noop,
        [OP_LAYOUTRETURN]       = nfsd4_encode_noop,
#endif
        [OP_SECINFO_NO_NAME]    = nfsd4_encode_secinfo_no_name,
        [OP_SEQUENCE]           = nfsd4_encode_sequence,
        [OP_SET_SSV]            = nfsd4_encode_noop,
        [OP_TEST_STATEID]       = nfsd4_encode_test_stateid,
        [OP_WANT_DELEGATION]    = nfsd4_encode_noop,
        [OP_DESTROY_CLIENTID]   = nfsd4_encode_noop,
        [OP_RECLAIM_COMPLETE]   = nfsd4_encode_noop,

        /* NFSv4.2 operations */
        [OP_ALLOCATE]           = nfsd4_encode_noop,
        [OP_COPY]               = nfsd4_encode_copy,
        [OP_COPY_NOTIFY]        = nfsd4_encode_copy_notify,
        [OP_DEALLOCATE]         = nfsd4_encode_noop,
        [OP_IO_ADVISE]          = nfsd4_encode_noop,
        [OP_LAYOUTERROR]        = nfsd4_encode_noop,
        [OP_LAYOUTSTATS]        = nfsd4_encode_noop,
        [OP_OFFLOAD_CANCEL]     = nfsd4_encode_noop,
        [OP_OFFLOAD_STATUS]     = nfsd4_encode_offload_status,
        [OP_READ_PLUS]          = nfsd4_encode_read_plus,
        [OP_SEEK]               = nfsd4_encode_seek,
        [OP_WRITE_SAME]         = nfsd4_encode_noop,
        [OP_CLONE]              = nfsd4_encode_noop,

        /* RFC 8276 extended atributes operations */
        [OP_GETXATTR]           = nfsd4_encode_getxattr,
        [OP_SETXATTR]           = nfsd4_encode_setxattr,
        [OP_LISTXATTRS]         = nfsd4_encode_listxattrs,
        [OP_REMOVEXATTR]        = nfsd4_encode_removexattr,
};

/*
 * Calculate whether we still have space to encode repsize bytes.
 * There are two considerations:
 *     - For NFS versions >=4.1, the size of the reply must stay within
 *       session limits
 *     - For all NFS versions, we must stay within limited preallocated
 *       buffer space.
 *
 * This is called before the operation is processed, so can only provide
 * an upper estimate.  For some nonidempotent operations (such as
 * getattr), it's not necessarily a problem if that estimate is wrong,
 * as we can fail it after processing without significant side effects.
 */
__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
{
        struct xdr_buf *buf = &resp->rqstp->rq_res;
        struct nfsd4_slot *slot = resp->cstate.slot;

        if (buf->len + respsize <= buf->buflen)
                return nfs_ok;
        if (!nfsd4_has_session(&resp->cstate))
                return nfserr_resource;
        if (slot->sl_flags & NFSD4_SLOT_CACHETHIS) {
                WARN_ON_ONCE(1);
                return nfserr_rep_too_big_to_cache;
        }
        return nfserr_rep_too_big;
}

static __be32 nfsd4_map_status(__be32 status, u32 minor)
{
        switch (status) {
        case nfs_ok:
                break;
        case nfserr_wrong_type:
                /* RFC 8881 - 15.1.2.9 */
                if (minor == 0)
                        status = nfserr_inval;
                break;
        case nfserr_symlink_not_dir:
                status = nfserr_symlink;
                break;
        }
        return status;
}

void
nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
        struct xdr_stream *xdr = resp->xdr;
        struct nfs4_stateowner *so = resp->cstate.replay_owner;
        struct svc_rqst *rqstp = resp->rqstp;
        const struct nfsd4_operation *opdesc = op->opdesc;
        unsigned int op_status_offset;
        nfsd4_enc encoder;

        if (xdr_stream_encode_u32(xdr, op->opnum) != XDR_UNIT)
                goto release;
        op_status_offset = xdr->buf->len;
        if (!xdr_reserve_space(xdr, XDR_UNIT))
                goto release;

        if (op->opnum == OP_ILLEGAL)
                goto status;
        if (op->status && opdesc &&
                        !(opdesc->op_flags & OP_NONTRIVIAL_ERROR_ENCODE))
                goto status;
        BUG_ON(op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
               !nfsd4_enc_ops[op->opnum]);
        encoder = nfsd4_enc_ops[op->opnum];
        op->status = encoder(resp, op->status, &op->u);
        if (op->status)
                trace_nfsd_compound_encode_err(rqstp, op->opnum, op->status);
        xdr_commit_encode(xdr);

        /* nfsd4_check_resp_size guarantees enough room for error status */
        if (!op->status) {
                int space_needed = 0;
                if (!nfsd4_last_compound_op(rqstp))
                        space_needed = COMPOUND_ERR_SLACK_SPACE;
                op->status = nfsd4_check_resp_size(resp, space_needed);
        }
        if (op->status == nfserr_resource && nfsd4_has_session(&resp->cstate)) {
                struct nfsd4_slot *slot = resp->cstate.slot;

                if (slot->sl_flags & NFSD4_SLOT_CACHETHIS)
                        op->status = nfserr_rep_too_big_to_cache;
                else
                        op->status = nfserr_rep_too_big;
        }
        if (op->status == nfserr_resource ||
            op->status == nfserr_rep_too_big ||
            op->status == nfserr_rep_too_big_to_cache) {
                /*
                 * The operation may have already been encoded or
                 * partially encoded.  No op returns anything additional
                 * in the case of one of these three errors, so we can
                 * just truncate back to after the status.  But it's a
                 * bug if we had to do this on a non-idempotent op:
                 */
                warn_on_nonidempotent_op(op);
                xdr_truncate_encode(xdr, op_status_offset + XDR_UNIT);
        } else if (so) {
                int len = xdr->buf->len - (op_status_offset + XDR_UNIT);

                so->so_replay.rp_status = op->status;
                if (len <= NFSD4_REPLAY_ISIZE) {
                        so->so_replay.rp_buflen = len;
                        read_bytes_from_xdr_buf(xdr->buf,
                                                op_status_offset + XDR_UNIT,
                                                so->so_replay.rp_buf, len);
                } else {
                        so->so_replay.rp_buflen = 0;
                }
        }
status:
        op->status = nfsd4_map_status(op->status,
                                      resp->cstate.minorversion);
        write_bytes_to_xdr_buf(xdr->buf, op_status_offset,
                               &op->status, XDR_UNIT);
release:
        if (opdesc && opdesc->op_release)
                opdesc->op_release(&op->u);

        /*
         * Account for pages consumed while encoding this operation.
         * The xdr_stream primitives don't manage rq_next_page.
         */
        rqstp->rq_next_page = xdr->page_ptr + 1;
}

/**
 * nfsd4_encode_replay - encode a result stored in the stateowner reply cache
 * @xdr: send buffer's XDR stream
 * @op: operation being replayed
 *
 * @op->replay->rp_buf contains the previously-sent already-encoded result.
 */
void nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op)
{
        struct nfs4_replay *rp = op->replay;

        trace_nfsd_stateowner_replay(op->opnum, rp);

        if (xdr_stream_encode_u32(xdr, op->opnum) != XDR_UNIT)
                return;
        if (xdr_stream_encode_be32(xdr, rp->rp_status) != XDR_UNIT)
                return;
        xdr_stream_encode_opaque_fixed(xdr, rp->rp_buf, rp->rp_buflen);
}

void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
{
        struct nfsd4_compoundargs *args = rqstp->rq_argp;

        if (args->ops != args->iops) {
                vfree(args->ops);
                args->ops = args->iops;
        }
        while (args->to_free) {
                struct svcxdr_tmpbuf *tb = args->to_free;
                args->to_free = tb->next;
                kfree(tb);
        }
}

bool
nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd4_compoundargs *args = rqstp->rq_argp;

        /* svcxdr_tmp_alloc */
        args->to_free = NULL;

        args->xdr = xdr;
        args->ops = args->iops;
        args->rqstp = rqstp;

        /*
         * NFSv4 operation decoders can invoke svc cache lookups
         * that trigger svc_defer() when RQ_USEDEFERRAL is set,
         * setting RQ_DROPME. This creates two problems:
         *
         * 1. Non-idempotency: Compounds make it too hard to avoid
         *    problems if a request is deferred and replayed.
         *
         * 2. Session slot leakage (NFSv4.1+): If RQ_DROPME is set
         *    during decode but SEQUENCE executes successfully, the
         *    session slot will be marked INUSE. The request is then
         *    dropped before encoding, so the slot is never released,
         *    rendering it permanently unusable by the client.
         */
        clear_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);

        return nfsd4_decode_compound(args);
}

bool
nfs4svc_encode_compoundres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        __be32 *p;

        /*
         * Send buffer space for the following items is reserved
         * at the top of nfsd4_proc_compound().
         */
        p = resp->statusp;

        *p++ = resp->cstate.status;
        *p++ = htonl(resp->taglen);
        memcpy(p, resp->tag, resp->taglen);
        p += XDR_QUADLEN(resp->taglen);
        *p++ = htonl(resp->opcnt);

        nfsd4_sequence_done(resp);
        return true;
}