Merge branch 'for-6.0/dax' into libnvdimm-fixes

[people/ms/linux.git] / fs / nfsd / nfs4xdr.c

/*
 *  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 <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 "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, u32 len)
{
        struct svcxdr_tmpbuf *tb;

        tb = kmalloc(sizeof(*tb) + len, GFP_KERNEL);
        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, u32 len)
{
        char *p = svcxdr_tmpalloc(argp, 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, u32 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;
}

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)
{
        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;
        }

        /* request sanity: did attrlist4 contain the expected number of words? */
        if (attrlist4_count != xdr_stream_pos(argp->xdr) - starting_pos)
                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_deviceid4(struct nfsd4_compoundargs *argp,
                       struct nfsd4_deviceid *devid)
{
        __be32 *p;

        p = xdr_inline_decode(argp->xdr, NFS4_DEVICEID4_SIZE);
        if (!p)
                return nfserr_bad_xdr;
        memcpy(devid, p, sizeof(*devid));
        return nfs_ok;
}

static __be32
nfsd4_decode_layoutupdate4(struct nfsd4_compoundargs *argp,
                           struct nfsd4_layoutcommit *lcp)
{
        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, &lcp->lc_up_len) < 0)
                return nfserr_bad_xdr;
        if (lcp->lc_up_len > 0) {
                lcp->lc_up_layout = xdr_inline_decode(argp->xdr, lcp->lc_up_len);
                if (!lcp->lc_up_layout)
                        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,
                    struct nfsd4_access *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, struct nfsd4_close *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, struct nfsd4_commit *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;
        return nfs_ok;
}

static __be32
nfsd4_decode_create(struct nfsd4_compoundargs *argp, struct nfsd4_create *create)
{
        __be32 *p, status;

        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);
        if (status)
                return status;

        return nfs_ok;
}

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

static inline __be32
nfsd4_decode_getattr(struct nfsd4_compoundargs *argp, struct nfsd4_getattr *getattr)
{
        return nfsd4_decode_bitmap4(argp, getattr->ga_bmval,
                                    ARRAY_SIZE(getattr->ga_bmval));
}

static __be32
nfsd4_decode_link(struct nfsd4_compoundargs *argp, struct nfsd4_link *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, struct nfsd4_lock *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, struct nfsd4_lockt *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, struct nfsd4_locku *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, struct nfsd4_lookup *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);
                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);
                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_MASK) {
        case NFS4_SHARE_WANT_NO_PREFERENCE:
        case NFS4_SHARE_WANT_READ_DELEG:
        case NFS4_SHARE_WANT_WRITE_DELEG:
        case NFS4_SHARE_WANT_ANY_DELEG:
        case NFS4_SHARE_WANT_NO_DELEG:
        case NFS4_SHARE_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, struct nfsd4_open *open)
{
        __be32 status;
        u32 dummy;

        memset(open->op_bmval, 0, sizeof(open->op_bmval));
        open->op_iattr.ia_valid = 0;
        open->op_openowner = NULL;

        open->op_xdr_error = 0;
        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, struct nfsd4_open_confirm *open_conf)
{
        __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;

        return nfs_ok;
}

static __be32
nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
{
        __be32 status;

        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, struct nfsd4_putfh *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;

        return nfs_ok;
}

static __be32
nfsd4_decode_putpubfh(struct nfsd4_compoundargs *argp, void *p)
{
        if (argp->minorversion == 0)
                return nfs_ok;
        return nfserr_notsupp;
}

static __be32
nfsd4_decode_read(struct nfsd4_compoundargs *argp, struct nfsd4_read *read)
{
        __be32 status;

        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, struct nfsd4_readdir *readdir)
{
        __be32 status;

        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, struct nfsd4_remove *remove)
{
        return nfsd4_decode_component4(argp, &remove->rm_name, &remove->rm_namelen);
}

static __be32
nfsd4_decode_rename(struct nfsd4_compoundargs *argp, struct nfsd4_rename *rename)
{
        __be32 status;

        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, clientid_t *clientid)
{
        return nfsd4_decode_clientid4(argp, clientid);
}

static __be32
nfsd4_decode_secinfo(struct nfsd4_compoundargs *argp,
                     struct nfsd4_secinfo *secinfo)
{
        return nfsd4_decode_component4(argp, &secinfo->si_name, &secinfo->si_namelen);
}

static __be32
nfsd4_decode_setattr(struct nfsd4_compoundargs *argp, struct nfsd4_setattr *setattr)
{
        __be32 status;

        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);
}

static __be32
nfsd4_decode_setclientid(struct nfsd4_compoundargs *argp, struct nfsd4_setclientid *setclientid)
{
        __be32 *p, status;

        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, struct nfsd4_setclientid_confirm *scd_c)
{
        __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, struct nfsd4_verify *verify)
{
        __be32 *p, status;

        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, struct nfsd4_write *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;

        return nfs_ok;
}

static __be32
nfsd4_decode_release_lockowner(struct nfsd4_compoundargs *argp, struct nfsd4_release_lockowner *rlockowner)
{
        __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, struct nfsd4_backchannel_ctl *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, struct nfsd4_bind_conn_to_session *bcts)
{
        u32 use_conn_in_rdma_mode;
        __be32 status;

        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,
                         struct nfsd4_exchange_id *exid)
{
        __be32 status;

        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,
                            struct nfsd4_create_session *sess)
{
        __be32 status;

        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;
        status = nfsd4_decode_cb_sec(argp, &sess->cb_sec);
        if (status)
                return status;

        return nfs_ok;
}

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

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

#ifdef CONFIG_NFSD_PNFS
static __be32
nfsd4_decode_getdeviceinfo(struct nfsd4_compoundargs *argp,
                struct nfsd4_getdeviceinfo *gdev)
{
        __be32 status;

        status = nfsd4_decode_deviceid4(argp, &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,
                          struct nfsd4_layoutcommit *lcp)
{
        __be32 *p, status;

        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_u32(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,
                struct nfsd4_layoutget *lgp)
{
        __be32 status;

        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,
                struct nfsd4_layoutreturn *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,
                                           struct nfsd4_secinfo_no_name *sin)
{
        if (xdr_stream_decode_u32(argp->xdr, &sin->sin_style) < 0)
                return nfserr_bad_xdr;
        return nfs_ok;
}

static __be32
nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
                      struct nfsd4_sequence *seq)
{
        __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++);
        seq->maxslots = be32_to_cpup(p++);
        seq->cachethis = be32_to_cpup(p);

        return nfs_ok;
}

static __be32
nfsd4_decode_test_stateid(struct nfsd4_compoundargs *argp, struct nfsd4_test_stateid *test_stateid)
{
        struct nfsd4_test_stateid_id *stateid;
        __be32 status;
        u32 i;

        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,
                                            struct nfsd4_destroy_clientid *dc)
{
        return nfsd4_decode_clientid4(argp, &dc->clientid);
}

static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp,
                                            struct nfsd4_reclaim_complete *rc)
{
        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,
                       struct nfsd4_fallocate *fallocate)
{
        __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, struct nfsd4_copy *copy)
{
        u32 consecutive, i, count, sync;
        struct nl4_server *ns_dummy;
        __be32 status;

        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(sizeof(struct nl4_server), GFP_KERNEL);
        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,
                         struct nfsd4_copy_notify *cn)
{
        __be32 status;

        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,
                            struct nfsd4_offload_status *os)
{
        return nfsd4_decode_stateid4(argp, &os->stateid);
}

static __be32
nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *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;

        return nfs_ok;
}

static __be32
nfsd4_decode_clone(struct nfsd4_compoundargs *argp, struct nfsd4_clone *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, u32 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,
                      struct nfsd4_getxattr *getxattr)
{
        __be32 status;
        u32 maxcount;

        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 status;
}

static __be32
nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
                      struct nfsd4_setxattr *setxattr)
{
        u32 flags, maxcount, size;
        __be32 status;

        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,
                        struct nfsd4_listxattrs *listxattrs)
{
        u32 maxcount;

        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,
                         struct nfsd4_removexattr *removexattr)
{
        return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
}

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

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

typedef __be32(*nfsd4_dec)(struct nfsd4_compoundargs *argp, void *);

static const nfsd4_dec nfsd4_dec_ops[] = {
        [OP_ACCESS]             = (nfsd4_dec)nfsd4_decode_access,
        [OP_CLOSE]              = (nfsd4_dec)nfsd4_decode_close,
        [OP_COMMIT]             = (nfsd4_dec)nfsd4_decode_commit,
        [OP_CREATE]             = (nfsd4_dec)nfsd4_decode_create,
        [OP_DELEGPURGE]         = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_DELEGRETURN]        = (nfsd4_dec)nfsd4_decode_delegreturn,
        [OP_GETATTR]            = (nfsd4_dec)nfsd4_decode_getattr,
        [OP_GETFH]              = (nfsd4_dec)nfsd4_decode_noop,
        [OP_LINK]               = (nfsd4_dec)nfsd4_decode_link,
        [OP_LOCK]               = (nfsd4_dec)nfsd4_decode_lock,
        [OP_LOCKT]              = (nfsd4_dec)nfsd4_decode_lockt,
        [OP_LOCKU]              = (nfsd4_dec)nfsd4_decode_locku,
        [OP_LOOKUP]             = (nfsd4_dec)nfsd4_decode_lookup,
        [OP_LOOKUPP]            = (nfsd4_dec)nfsd4_decode_noop,
        [OP_NVERIFY]            = (nfsd4_dec)nfsd4_decode_verify,
        [OP_OPEN]               = (nfsd4_dec)nfsd4_decode_open,
        [OP_OPENATTR]           = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_OPEN_CONFIRM]       = (nfsd4_dec)nfsd4_decode_open_confirm,
        [OP_OPEN_DOWNGRADE]     = (nfsd4_dec)nfsd4_decode_open_downgrade,
        [OP_PUTFH]              = (nfsd4_dec)nfsd4_decode_putfh,
        [OP_PUTPUBFH]           = (nfsd4_dec)nfsd4_decode_putpubfh,
        [OP_PUTROOTFH]          = (nfsd4_dec)nfsd4_decode_noop,
        [OP_READ]               = (nfsd4_dec)nfsd4_decode_read,
        [OP_READDIR]            = (nfsd4_dec)nfsd4_decode_readdir,
        [OP_READLINK]           = (nfsd4_dec)nfsd4_decode_noop,
        [OP_REMOVE]             = (nfsd4_dec)nfsd4_decode_remove,
        [OP_RENAME]             = (nfsd4_dec)nfsd4_decode_rename,
        [OP_RENEW]              = (nfsd4_dec)nfsd4_decode_renew,
        [OP_RESTOREFH]          = (nfsd4_dec)nfsd4_decode_noop,
        [OP_SAVEFH]             = (nfsd4_dec)nfsd4_decode_noop,
        [OP_SECINFO]            = (nfsd4_dec)nfsd4_decode_secinfo,
        [OP_SETATTR]            = (nfsd4_dec)nfsd4_decode_setattr,
        [OP_SETCLIENTID]        = (nfsd4_dec)nfsd4_decode_setclientid,
        [OP_SETCLIENTID_CONFIRM] = (nfsd4_dec)nfsd4_decode_setclientid_confirm,
        [OP_VERIFY]             = (nfsd4_dec)nfsd4_decode_verify,
        [OP_WRITE]              = (nfsd4_dec)nfsd4_decode_write,
        [OP_RELEASE_LOCKOWNER]  = (nfsd4_dec)nfsd4_decode_release_lockowner,

        /* new operations for NFSv4.1 */
        [OP_BACKCHANNEL_CTL]    = (nfsd4_dec)nfsd4_decode_backchannel_ctl,
        [OP_BIND_CONN_TO_SESSION]= (nfsd4_dec)nfsd4_decode_bind_conn_to_session,
        [OP_EXCHANGE_ID]        = (nfsd4_dec)nfsd4_decode_exchange_id,
        [OP_CREATE_SESSION]     = (nfsd4_dec)nfsd4_decode_create_session,
        [OP_DESTROY_SESSION]    = (nfsd4_dec)nfsd4_decode_destroy_session,
        [OP_FREE_STATEID]       = (nfsd4_dec)nfsd4_decode_free_stateid,
        [OP_GET_DIR_DELEGATION] = (nfsd4_dec)nfsd4_decode_notsupp,
#ifdef CONFIG_NFSD_PNFS
        [OP_GETDEVICEINFO]      = (nfsd4_dec)nfsd4_decode_getdeviceinfo,
        [OP_GETDEVICELIST]      = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTCOMMIT]       = (nfsd4_dec)nfsd4_decode_layoutcommit,
        [OP_LAYOUTGET]          = (nfsd4_dec)nfsd4_decode_layoutget,
        [OP_LAYOUTRETURN]       = (nfsd4_dec)nfsd4_decode_layoutreturn,
#else
        [OP_GETDEVICEINFO]      = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_GETDEVICELIST]      = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTCOMMIT]       = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTGET]          = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTRETURN]       = (nfsd4_dec)nfsd4_decode_notsupp,
#endif
        [OP_SECINFO_NO_NAME]    = (nfsd4_dec)nfsd4_decode_secinfo_no_name,
        [OP_SEQUENCE]           = (nfsd4_dec)nfsd4_decode_sequence,
        [OP_SET_SSV]            = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_TEST_STATEID]       = (nfsd4_dec)nfsd4_decode_test_stateid,
        [OP_WANT_DELEGATION]    = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_DESTROY_CLIENTID]   = (nfsd4_dec)nfsd4_decode_destroy_clientid,
        [OP_RECLAIM_COMPLETE]   = (nfsd4_dec)nfsd4_decode_reclaim_complete,

        /* new operations for NFSv4.2 */
        [OP_ALLOCATE]           = (nfsd4_dec)nfsd4_decode_fallocate,
        [OP_COPY]               = (nfsd4_dec)nfsd4_decode_copy,
        [OP_COPY_NOTIFY]        = (nfsd4_dec)nfsd4_decode_copy_notify,
        [OP_DEALLOCATE]         = (nfsd4_dec)nfsd4_decode_fallocate,
        [OP_IO_ADVISE]          = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTERROR]        = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_LAYOUTSTATS]        = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_OFFLOAD_CANCEL]     = (nfsd4_dec)nfsd4_decode_offload_status,
        [OP_OFFLOAD_STATUS]     = (nfsd4_dec)nfsd4_decode_offload_status,
        [OP_READ_PLUS]          = (nfsd4_dec)nfsd4_decode_read,
        [OP_SEEK]               = (nfsd4_dec)nfsd4_decode_seek,
        [OP_WRITE_SAME]         = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_CLONE]              = (nfsd4_dec)nfsd4_decode_clone,
        /* RFC 8276 extended atributes operations */
        [OP_GETXATTR]           = (nfsd4_dec)nfsd4_decode_getxattr,
        [OP_SETXATTR]           = (nfsd4_dec)nfsd4_decode_setxattr,
        [OP_LISTXATTRS]         = (nfsd4_dec)nfsd4_decode_listxattrs,
        [OP_REMOVEXATTR]        = (nfsd4_dec)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->opcnt) < 0)
                return false;

        /*
         * NFS4ERR_RESOURCE is a more helpful error than GARBAGE_ARGS
         * here, so we return success at the xdr level so that
         * nfsd4_proc can handle this is an NFS-level error.
         */
        if (argp->opcnt > NFSD_MAX_OPS_PER_COMPOUND)
                return true;

        if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
                argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
                if (!argp->ops) {
                        argp->ops = argp->iops;
                        dprintk("nfsd: couldn't allocate room for COMPOUND\n");
                        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;

                if (xdr_stream_decode_u32(argp->xdr, &op->opnum) < 0)
                        return false;
                if (nfsd4_opnum_in_range(argp, 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;
                }
                op->opdesc = OPDESC(op);
                /*
                 * 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(argp->rqstp, max_reply + readbytes);
        argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE;

        if (readcount > 1 || max_reply > PAGE_SIZE - auth_slack)
                __clear_bit(RQ_SPLICE_OK, &argp->rqstp->rq_flags);

        return true;
}

static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode,
                             struct svc_export *exp)
{
        if (exp->ex_flags & NFSEXP_V4ROOT) {
                *p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time));
                *p++ = 0;
        } else
                p = xdr_encode_hyper(p, nfsd4_change_attribute(stat, inode));
        return p;
}

/*
 * 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 *encode_time_delta(__be32 *p, struct inode *inode)
{
        struct timespec64 ts;
        u32 ns;

        ns = max_t(u32, NSEC_PER_SEC/HZ, inode->i_sb->s_time_gran);
        ts = ns_to_timespec64(ns);

        p = xdr_encode_hyper(p, ts.tv_sec);
        *p++ = cpu_to_be32(ts.tv_nsec);

        return p;
}

static __be32 *encode_cinfo(__be32 *p, struct nfsd4_change_info *c)
{
        *p++ = cpu_to_be32(c->atomic);
        p = xdr_encode_hyper(p, c->before_change);
        p = xdr_encode_hyper(p, c->after_change);
        return p;
}

/* 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;
        int strlen, count=0;
        char *str, *end, *next;

        dprintk("nfsd4_encode_components(%s)\n", components);

        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 */;

                strlen = end - str;
                if (strlen) {
                        p = xdr_reserve_space(xdr, strlen + 4);
                        if (!p)
                                return nfserr_resource;
                        p = xdr_encode_opaque(p, str, strlen);
                        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);
}

/*
 * encode a location element of a fs_locations structure
 */
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 0;
}

/*
 * Encode a path in RFC3530 'pathname4' format
 */
static __be32 nfsd4_encode_path(struct xdr_stream *xdr,
                                const struct path *root,
                                const struct path *path)
{
        struct path cur = *path;
        __be32 *p;
        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;
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                goto out_free;
        *p++ = cpu_to_be32(ncomponents);

        while (ncomponents) {
                struct dentry *dentry = components[ncomponents - 1];
                unsigned int len;

                spin_lock(&dentry->d_lock);
                len = dentry->d_name.len;
                p = xdr_reserve_space(xdr, len + 4);
                if (!p) {
                        spin_unlock(&dentry->d_lock);
                        goto out_free;
                }
                p = xdr_encode_opaque(p, dentry->d_name.name, len);
                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_fsloc_fsroot(struct xdr_stream *xdr,
                        struct svc_rqst *rqstp, const struct path *path)
{
        struct svc_export *exp_ps;
        __be32 res;

        exp_ps = rqst_find_fsidzero_export(rqstp);
        if (IS_ERR(exp_ps))
                return nfserrno(PTR_ERR(exp_ps));
        res = nfsd4_encode_path(xdr, &exp_ps->ex_path, path);
        exp_put(exp_ps);
        return res;
}

/*
 *  encode a fs_locations structure
 */
static __be32 nfsd4_encode_fs_locations(struct xdr_stream *xdr,
                        struct svc_rqst *rqstp, struct svc_export *exp)
{
        __be32 status;
        int i;
        __be32 *p;
        struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;

        status = nfsd4_encode_fsloc_fsroot(xdr, rqstp, &exp->ex_path);
        if (status)
                return status;
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(fslocs->locations_count);
        for (i=0; i<fslocs->locations_count; i++) {
                status = nfsd4_encode_fs_location4(xdr, &fslocs->locations[i]);
                if (status)
                        return status;
        }
        return 0;
}

static u32 nfs4_file_type(umode_t mode)
{
        switch (mode & S_IFMT) {
        case S_IFIFO:   return NF4FIFO;
        case S_IFCHR:   return NF4CHR;
        case S_IFDIR:   return NF4DIR;
        case S_IFBLK:   return NF4BLK;
        case S_IFLNK:   return NF4LNK;
        case S_IFREG:   return NF4REG;
        case S_IFSOCK:  return NF4SOCK;
        default:        return NF4BAD;
        }
}

static inline __be32
nfsd4_encode_aclname(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                     struct nfs4_ace *ace)
{
        if (ace->whotype != NFS4_ACL_WHO_NAMED)
                return nfs4_acl_write_who(xdr, ace->whotype);
        else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                return nfsd4_encode_group(xdr, rqstp, ace->who_gid);
        else
                return nfsd4_encode_user(xdr, rqstp, ace->who_uid);
}

static inline __be32
nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
{
        __be32          *p;
        unsigned long   i = hweight_long(layout_types);

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

        *p++ = cpu_to_be32(i);

        for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
                if (layout_types & (1 << i))
                        *p++ = cpu_to_be32(i);

        return 0;
}

#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,
                            void *context, int len)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, 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, len);
        return 0;
}
#else
static inline __be32
nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
                            void *context, int len)
{ return 0; }
#endif

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 get_parent_attributes(struct svc_export *exp, struct kstat *stat)
{
        struct path path = exp->ex_path;
        int err;

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

static __be32
nfsd4_encode_bitmap(struct xdr_stream *xdr, u32 bmval0, u32 bmval1, u32 bmval2)
{
        __be32 *p;

        if (bmval2) {
                p = xdr_reserve_space(xdr, 16);
                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, 12);
                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, 8);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
                *p++ = cpu_to_be32(bmval0);
        }

        return 0;
out_resource:
        return nfserr_resource;
}

/*
 * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
 * ourselves.
 */
static __be32
nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
                struct svc_export *exp,
                struct dentry *dentry, u32 *bmval,
                struct svc_rqst *rqstp, int ignore_crossmnt)
{
        u32 bmval0 = bmval[0];
        u32 bmval1 = bmval[1];
        u32 bmval2 = bmval[2];
        struct kstat stat;
        struct svc_fh *tempfh = NULL;
        struct kstatfs statfs;
        __be32 *p, *attrlen_p;
        int starting_len = xdr->buf->len;
        int attrlen_offset;
        u32 dummy;
        u64 dummy64;
        u32 rdattr_err = 0;
        __be32 status;
        int err;
        struct nfs4_acl *acl = NULL;
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        void *context = NULL;
        int contextlen;
#endif
        bool contextsupport = false;
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        u32 minorversion = resp->cstate.minorversion;
        struct path path = {
                .mnt    = exp->ex_path.mnt,
                .dentry = dentry,
        };
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

        BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
        BUG_ON(!nfsd_attrs_supported(minorversion, bmval));

        if (exp->ex_fslocs.migrated) {
                status = fattr_handle_absent_fs(&bmval0, &bmval1, &bmval2, &rdattr_err);
                if (status)
                        goto out;
        }

        err = vfs_getattr(&path, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
        if (err)
                goto out_nfserr;
        if (!(stat.result_mask & STATX_BTIME))
                /* underlying FS does not offer btime so we can't share it */
                bmval1 &= ~FATTR4_WORD1_TIME_CREATE;
        if ((bmval0 & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
                        FATTR4_WORD0_FILES_TOTAL | FATTR4_WORD0_MAXNAME)) ||
            (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
                       FATTR4_WORD1_SPACE_TOTAL))) {
                err = vfs_statfs(&path, &statfs);
                if (err)
                        goto out_nfserr;
        }
        if ((bmval0 & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) && !fhp) {
                tempfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
                status = nfserr_jukebox;
                if (!tempfh)
                        goto out;
                fh_init(tempfh, NFS4_FHSIZE);
                status = fh_compose(tempfh, exp, dentry, NULL);
                if (status)
                        goto out;
                fhp = tempfh;
        }
        if (bmval0 & FATTR4_WORD0_ACL) {
                err = nfsd4_get_nfs4_acl(rqstp, dentry, &acl);
                if (err == -EOPNOTSUPP)
                        bmval0 &= ~FATTR4_WORD0_ACL;
                else if (err == -EINVAL) {
                        status = nfserr_attrnotsupp;
                        goto out;
                } else if (err != 0)
                        goto out_nfserr;
        }

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        if ((bmval2 & FATTR4_WORD2_SECURITY_LABEL) ||
             bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
                if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
                        err = security_inode_getsecctx(d_inode(dentry),
                                                &context, &contextlen);
                else
                        err = -EOPNOTSUPP;
                contextsupport = (err == 0);
                if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
                        if (err == -EOPNOTSUPP)
                                bmval2 &= ~FATTR4_WORD2_SECURITY_LABEL;
                        else if (err)
                                goto out_nfserr;
                }
        }
#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */

        status = nfsd4_encode_bitmap(xdr, bmval0, bmval1, bmval2);
        if (status)
                goto out;

        attrlen_offset = xdr->buf->len;
        attrlen_p = xdr_reserve_space(xdr, XDR_UNIT);
        if (!attrlen_p)
                goto out_resource;

        if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
                u32 supp[3];

                memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));

                if (!IS_POSIXACL(dentry->d_inode))
                        supp[0] &= ~FATTR4_WORD0_ACL;
                if (!contextsupport)
                        supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
                if (!supp[2]) {
                        p = xdr_reserve_space(xdr, 12);
                        if (!p)
                                goto out_resource;
                        *p++ = cpu_to_be32(2);
                        *p++ = cpu_to_be32(supp[0]);
                        *p++ = cpu_to_be32(supp[1]);
                } else {
                        p = xdr_reserve_space(xdr, 16);
                        if (!p)
                                goto out_resource;
                        *p++ = cpu_to_be32(3);
                        *p++ = cpu_to_be32(supp[0]);
                        *p++ = cpu_to_be32(supp[1]);
                        *p++ = cpu_to_be32(supp[2]);
                }
        }
        if (bmval0 & FATTR4_WORD0_TYPE) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                dummy = nfs4_file_type(stat.mode);
                if (dummy == NF4BAD) {
                        status = nfserr_serverfault;
                        goto out;
                }
                *p++ = cpu_to_be32(dummy);
        }
        if (bmval0 & FATTR4_WORD0_FH_EXPIRE_TYPE) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
                        *p++ = cpu_to_be32(NFS4_FH_PERSISTENT);
                else
                        *p++ = cpu_to_be32(NFS4_FH_PERSISTENT|
                                                NFS4_FH_VOL_RENAME);
        }
        if (bmval0 & FATTR4_WORD0_CHANGE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = encode_change(p, &stat, d_inode(dentry), exp);
        }
        if (bmval0 & FATTR4_WORD0_SIZE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, stat.size);
        }
        if (bmval0 & FATTR4_WORD0_LINK_SUPPORT) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_SYMLINK_SUPPORT) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_NAMED_ATTR) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(0);
        }
        if (bmval0 & FATTR4_WORD0_FSID) {
                p = xdr_reserve_space(xdr, 16);
                if (!p)
                        goto out_resource;
                if (exp->ex_fslocs.migrated) {
                        p = xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MAJOR);
                        p = xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MINOR);
                } else switch(fsid_source(fhp)) {
                case FSIDSOURCE_FSID:
                        p = xdr_encode_hyper(p, (u64)exp->ex_fsid);
                        p = xdr_encode_hyper(p, (u64)0);
                        break;
                case FSIDSOURCE_DEV:
                        *p++ = cpu_to_be32(0);
                        *p++ = cpu_to_be32(MAJOR(stat.dev));
                        *p++ = cpu_to_be32(0);
                        *p++ = cpu_to_be32(MINOR(stat.dev));
                        break;
                case FSIDSOURCE_UUID:
                        p = xdr_encode_opaque_fixed(p, exp->ex_uuid,
                                                                EX_UUID_LEN);
                        break;
                }
        }
        if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(0);
        }
        if (bmval0 & FATTR4_WORD0_LEASE_TIME) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(nn->nfsd4_lease);
        }
        if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(rdattr_err);
        }
        if (bmval0 & FATTR4_WORD0_ACL) {
                struct nfs4_ace *ace;

                if (acl == NULL) {
                        p = xdr_reserve_space(xdr, 4);
                        if (!p)
                                goto out_resource;

                        *p++ = cpu_to_be32(0);
                        goto out_acl;
                }
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(acl->naces);

                for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
                        p = xdr_reserve_space(xdr, 4*3);
                        if (!p)
                                goto out_resource;
                        *p++ = cpu_to_be32(ace->type);
                        *p++ = cpu_to_be32(ace->flag);
                        *p++ = cpu_to_be32(ace->access_mask &
                                                        NFS4_ACE_MASK_ALL);
                        status = nfsd4_encode_aclname(xdr, rqstp, ace);
                        if (status)
                                goto out;
                }
        }
out_acl:
        if (bmval0 & FATTR4_WORD0_ACLSUPPORT) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(IS_POSIXACL(dentry->d_inode) ?
                        ACL4_SUPPORT_ALLOW_ACL|ACL4_SUPPORT_DENY_ACL : 0);
        }
        if (bmval0 & FATTR4_WORD0_CANSETTIME) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(0);
        }
        if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_CHOWN_RESTRICTED) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_FILEHANDLE) {
                p = xdr_reserve_space(xdr, fhp->fh_handle.fh_size + 4);
                if (!p)
                        goto out_resource;
                p = xdr_encode_opaque(p, &fhp->fh_handle.fh_raw,
                                        fhp->fh_handle.fh_size);
        }
        if (bmval0 & FATTR4_WORD0_FILEID) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, stat.ino);
        }
        if (bmval0 & FATTR4_WORD0_FILES_AVAIL) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (u64) statfs.f_ffree);
        }
        if (bmval0 & FATTR4_WORD0_FILES_FREE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (u64) statfs.f_ffree);
        }
        if (bmval0 & FATTR4_WORD0_FILES_TOTAL) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (u64) statfs.f_files);
        }
        if (bmval0 & FATTR4_WORD0_FS_LOCATIONS) {
                status = nfsd4_encode_fs_locations(xdr, rqstp, exp);
                if (status)
                        goto out;
        }
        if (bmval0 & FATTR4_WORD0_HOMOGENEOUS) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval0 & FATTR4_WORD0_MAXFILESIZE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, exp->ex_path.mnt->mnt_sb->s_maxbytes);
        }
        if (bmval0 & FATTR4_WORD0_MAXLINK) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(255);
        }
        if (bmval0 & FATTR4_WORD0_MAXNAME) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(statfs.f_namelen);
        }
        if (bmval0 & FATTR4_WORD0_MAXREAD) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (u64) svc_max_payload(rqstp));
        }
        if (bmval0 & FATTR4_WORD0_MAXWRITE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (u64) svc_max_payload(rqstp));
        }
        if (bmval1 & FATTR4_WORD1_MODE) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(stat.mode & S_IALLUGO);
        }
        if (bmval1 & FATTR4_WORD1_NO_TRUNC) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(1);
        }
        if (bmval1 & FATTR4_WORD1_NUMLINKS) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(stat.nlink);
        }
        if (bmval1 & FATTR4_WORD1_OWNER) {
                status = nfsd4_encode_user(xdr, rqstp, stat.uid);
                if (status)
                        goto out;
        }
        if (bmval1 & FATTR4_WORD1_OWNER_GROUP) {
                status = nfsd4_encode_group(xdr, rqstp, stat.gid);
                if (status)
                        goto out;
        }
        if (bmval1 & FATTR4_WORD1_RAWDEV) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32((u32) MAJOR(stat.rdev));
                *p++ = cpu_to_be32((u32) MINOR(stat.rdev));
        }
        if (bmval1 & FATTR4_WORD1_SPACE_AVAIL) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                dummy64 = (u64)statfs.f_bavail * (u64)statfs.f_bsize;
                p = xdr_encode_hyper(p, dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_FREE) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                dummy64 = (u64)statfs.f_bfree * (u64)statfs.f_bsize;
                p = xdr_encode_hyper(p, dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_TOTAL) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                dummy64 = (u64)statfs.f_blocks * (u64)statfs.f_bsize;
                p = xdr_encode_hyper(p, dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_USED) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                dummy64 = (u64)stat.blocks << 9;
                p = xdr_encode_hyper(p, dummy64);
        }
        if (bmval1 & FATTR4_WORD1_TIME_ACCESS) {
                p = xdr_reserve_space(xdr, 12);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (s64)stat.atime.tv_sec);
                *p++ = cpu_to_be32(stat.atime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
                p = xdr_reserve_space(xdr, 12);
                if (!p)
                        goto out_resource;
                p = encode_time_delta(p, d_inode(dentry));
        }
        if (bmval1 & FATTR4_WORD1_TIME_METADATA) {
                p = xdr_reserve_space(xdr, 12);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (s64)stat.ctime.tv_sec);
                *p++ = cpu_to_be32(stat.ctime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_TIME_MODIFY) {
                p = xdr_reserve_space(xdr, 12);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (s64)stat.mtime.tv_sec);
                *p++ = cpu_to_be32(stat.mtime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_TIME_CREATE) {
                p = xdr_reserve_space(xdr, 12);
                if (!p)
                        goto out_resource;
                p = xdr_encode_hyper(p, (s64)stat.btime.tv_sec);
                *p++ = cpu_to_be32(stat.btime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
                struct kstat parent_stat;
                u64 ino = stat.ino;

                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        goto out_resource;
                /*
                 * Get parent's attributes if not ignoring crossmount
                 * and this is the root of a cross-mounted filesystem.
                 */
                if (ignore_crossmnt == 0 &&
                    dentry == exp->ex_path.mnt->mnt_root) {
                        err = get_parent_attributes(exp, &parent_stat);
                        if (err)
                                goto out_nfserr;
                        ino = parent_stat.ino;
                }
                p = xdr_encode_hyper(p, ino);
        }
#ifdef CONFIG_NFSD_PNFS
        if (bmval1 & FATTR4_WORD1_FS_LAYOUT_TYPES) {
                status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
                if (status)
                        goto out;
        }

        if (bmval2 & FATTR4_WORD2_LAYOUT_TYPES) {
                status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
                if (status)
                        goto out;
        }

        if (bmval2 & FATTR4_WORD2_LAYOUT_BLKSIZE) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                *p++ = cpu_to_be32(stat.blksize);
        }
#endif /* CONFIG_NFSD_PNFS */
        if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
                u32 supp[3];

                memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));
                supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
                supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
                supp[2] &= NFSD_SUPPATTR_EXCLCREAT_WORD2;

                status = nfsd4_encode_bitmap(xdr, supp[0], supp[1], supp[2]);
                if (status)
                        goto out;
        }

#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
                status = nfsd4_encode_security_label(xdr, rqstp, context,
                                                                contextlen);
                if (status)
                        goto out;
        }
#endif

        if (bmval2 & FATTR4_WORD2_XATTR_SUPPORT) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        goto out_resource;
                err = xattr_supported_namespace(d_inode(dentry),
                                                XATTR_USER_PREFIX);
                *p++ = cpu_to_be32(err == 0);
        }

        *attrlen_p = cpu_to_be32(xdr->buf->len - attrlen_offset - XDR_UNIT);
        status = nfs_ok;

out:
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
        if (context)
                security_release_secctx(context, contextlen);
#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
        kfree(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_fattr(&xdr, fhp, exp, dentry, bmval, rqstp,
                                                        ignore_crossmnt);
        *p = xdr.p;
        return ret;
}

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_dirent_fattr(struct xdr_stream *xdr, 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_positive_unlocked(name, cd->rd_fhp->fh_dentry, namlen);
        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);
                if (nfserr)
                        goto out_put;

        }
out_encode:
        nfserr = nfsd4_encode_fattr(xdr, NULL, exp, dentry, cd->rd_bmval,
                                        cd->rd_rqstp, ignore_crossmnt);
out_put:
        dput(dentry);
        exp_put(exp);
        return nfserr;
}

static __be32 *
nfsd4_encode_rdattr_error(struct xdr_stream *xdr, __be32 nfserr)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return NULL;
        *p++ = htonl(2);
        *p++ = htonl(FATTR4_WORD0_RDATTR_ERROR); /* bmval0 */
        *p++ = htonl(0);                         /* bmval1 */

        *p++ = htonl(4);     /* attribute length */
        *p++ = nfserr;       /* no htonl */
        return p;
}

static int
nfsd4_encode_dirent(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;
        __be64 wire_offset;
        __be32 *p;

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

        if (cd->cookie_offset) {
                wire_offset = cpu_to_be64(offset);
                write_bytes_to_xdr_buf(xdr->buf, cd->cookie_offset,
                                                        &wire_offset, 8);
        }

        p = xdr_reserve_space(xdr, 4);
        if (!p)
                goto fail;
        *p++ = xdr_one;                             /* mark entry present */
        cookie_offset = xdr->buf->len;
        p = xdr_reserve_space(xdr, 3*4 + namlen);
        if (!p)
                goto fail;
        p = xdr_encode_hyper(p, OFFSET_MAX);        /* offset of next entry */
        p = xdr_encode_array(p, name, namlen);      /* name length & name */

        nfserr = nfsd4_encode_dirent_fattr(xdr, 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;
        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;
                p = nfsd4_encode_rdattr_error(xdr, nfserr);
                if (p == NULL) {
                        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_stateid(struct xdr_stream *xdr, stateid_t *sid)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, sizeof(stateid_t));
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(sid->si_generation);
        p = xdr_encode_opaque_fixed(p, &sid->si_opaque,
                                        sizeof(stateid_opaque_t));
        return 0;
}

static __be32
nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 8);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(access->ac_supported);
        *p++ = cpu_to_be32(access->ac_resp_access);
        return 0;
}

static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 8);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_opaque_fixed(p, bcts->sessionid.data,
                                        NFS4_MAX_SESSIONID_LEN);
        *p++ = cpu_to_be32(bcts->dir);
        /* Upshifting from TCP to RDMA is not supported */
        *p++ = cpu_to_be32(0);
        return 0;
}

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

        return nfsd4_encode_stateid(xdr, &close->cl_stateid);
}


static __be32
nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_commit *commit)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_opaque_fixed(p, commit->co_verf.data,
                                                NFS4_VERIFIER_SIZE);
        return 0;
}

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

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return nfserr_resource;
        encode_cinfo(p, &create->cr_cinfo);
        return nfsd4_encode_bitmap(xdr, create->cr_bmval[0],
                        create->cr_bmval[1], create->cr_bmval[2]);
}

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

        return nfsd4_encode_fattr(xdr, fhp, fhp->fh_export, fhp->fh_dentry,
                                    getattr->ga_bmval, resp->rqstp, 0);
}

static __be32
nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr, struct svc_fh **fhpp)
{
        struct xdr_stream *xdr = resp->xdr;
        struct svc_fh *fhp = *fhpp;
        unsigned int len;
        __be32 *p;

        len = fhp->fh_handle.fh_size;
        p = xdr_reserve_space(xdr, len + 4);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_opaque(p, &fhp->fh_handle.fh_raw, len);
        return 0;
}

/*
* Including all fields other than the name, a LOCK4denied structure requires
*   8(clientid) + 4(namelen) + 8(offset) + 8(length) + 4(type) = 32 bytes.
*/
static __be32
nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
{
        struct xdr_netobj *conf = &ld->ld_owner;
        __be32 *p;

again:
        p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));
        if (!p) {
                /*
                 * Don't fail to return the result just because we can't
                 * return the conflicting open:
                 */
                if (conf->len) {
                        kfree(conf->data);
                        conf->len = 0;
                        conf->data = NULL;
                        goto again;
                }
                return nfserr_resource;
        }
        p = xdr_encode_hyper(p, ld->ld_start);
        p = xdr_encode_hyper(p, ld->ld_length);
        *p++ = cpu_to_be32(ld->ld_type);
        if (conf->len) {
                p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8);
                p = xdr_encode_opaque(p, conf->data, conf->len);
                kfree(conf->data);
        }  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */
                p = xdr_encode_hyper(p, (u64)0); /* clientid */
                *p++ = cpu_to_be32(0); /* length of owner name */
        }
        return nfserr_denied;
}

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

        if (!nfserr)
                nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);
        else if (nfserr == nfserr_denied)
                nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);

        return nfserr;
}

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

        if (nfserr == nfserr_denied)
                nfsd4_encode_lock_denied(xdr, &lockt->lt_denied);
        return nfserr;
}

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

        return nfsd4_encode_stateid(xdr, &locku->lu_stateid);
}


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

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return nfserr_resource;
        p = encode_cinfo(p, &link->li_cinfo);
        return 0;
}


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

        nfserr = nfsd4_encode_stateid(xdr, &open->op_stateid);
        if (nfserr)
                return nfserr;
        p = xdr_reserve_space(xdr, 24);
        if (!p)
                return nfserr_resource;
        p = encode_cinfo(p, &open->op_cinfo);
        *p++ = cpu_to_be32(open->op_rflags);

        nfserr = nfsd4_encode_bitmap(xdr, open->op_bmval[0], open->op_bmval[1],
                                        open->op_bmval[2]);
        if (nfserr)
                return nfserr;

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

        *p++ = cpu_to_be32(open->op_delegate_type);
        switch (open->op_delegate_type) {
        case NFS4_OPEN_DELEGATE_NONE:
                break;
        case NFS4_OPEN_DELEGATE_READ:
                nfserr = nfsd4_encode_stateid(xdr, &open->op_delegate_stateid);
                if (nfserr)
                        return nfserr;
                p = xdr_reserve_space(xdr, 20);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(open->op_recall);

                /*
                 * TODO: ACE's in delegations
                 */
                *p++ = cpu_to_be32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);   /* XXX: is NULL principal ok? */
                break;
        case NFS4_OPEN_DELEGATE_WRITE:
                nfserr = nfsd4_encode_stateid(xdr, &open->op_delegate_stateid);
                if (nfserr)
                        return nfserr;
                p = xdr_reserve_space(xdr, 32);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(0);

                /*
                 * TODO: space_limit's in delegations
                 */
                *p++ = cpu_to_be32(NFS4_LIMIT_SIZE);
                *p++ = cpu_to_be32(~(u32)0);
                *p++ = cpu_to_be32(~(u32)0);

                /*
                 * TODO: ACE's in delegations
                 */
                *p++ = cpu_to_be32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);   /* XXX: is NULL principal ok? */
                break;
        case NFS4_OPEN_DELEGATE_NONE_EXT: /* 4.1 */
                switch (open->op_why_no_deleg) {
                case WND4_CONTENTION:
                case WND4_RESOURCE:
                        p = xdr_reserve_space(xdr, 8);
                        if (!p)
                                return nfserr_resource;
                        *p++ = cpu_to_be32(open->op_why_no_deleg);
                        /* deleg signaling not supported yet: */
                        *p++ = cpu_to_be32(0);
                        break;
                default:
                        p = xdr_reserve_space(xdr, 4);
                        if (!p)
                                return nfserr_resource;
                        *p++ = cpu_to_be32(open->op_why_no_deleg);
                }
                break;
        default:
                BUG();
        }
        /* XXX save filehandle here */
        return 0;
}

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

        return nfsd4_encode_stateid(xdr, &oc->oc_resp_stateid);
}

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

        return nfsd4_encode_stateid(xdr, &od->od_stateid);
}

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;

        /* Make sure there will be room for padding if needed */
        if (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;
        status = svc_encode_result_payload(read->rd_rqstp,
                                           buf->head[0].iov_len, maxcount);
        if (status) {
                nfserr = nfserrno(status);
                goto out_err;
        }

        buf->page_len = maxcount;
        buf->len += maxcount;
        xdr->page_ptr += (buf->page_base + maxcount + PAGE_SIZE - 1)
                                                        / PAGE_SIZE;

        /* Use rest of head for padding and remaining ops: */
        buf->tail[0].iov_base = xdr->p;
        buf->tail[0].iov_len = 0;
        xdr->iov = buf->tail;
        if (maxcount&3) {
                int pad = 4 - (maxcount&3);

                *(xdr->p++) = 0;

                buf->tail[0].iov_base += maxcount&3;
                buf->tail[0].iov_len = pad;
                buf->len += pad;
        }

        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 0;

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,
                                 struct file *file, unsigned long maxcount)
{
        struct xdr_stream *xdr = resp->xdr;
        unsigned int starting_len = xdr->buf->len;
        __be32 zero = xdr_zero;
        __be32 nfserr;

        read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, maxcount);
        if (read->rd_vlen < 0)
                return nfserr_resource;

        nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
                            resp->rqstp->rq_vec, read->rd_vlen, &maxcount,
                            &read->rd_eof);
        read->rd_length = maxcount;
        if (nfserr)
                return nfserr;
        if (svc_encode_result_payload(resp->rqstp, starting_len, maxcount))
                return nfserr_io;
        xdr_truncate_encode(xdr, starting_len + xdr_align_size(maxcount));

        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,
                  struct nfsd4_read *read)
{
        bool splice_ok = test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags);
        unsigned long maxcount;
        struct xdr_stream *xdr = resp->xdr;
        struct file *file;
        int starting_len = xdr->buf->len;
        __be32 *p;

        if (nfserr)
                return nfserr;
        file = read->rd_nf->nf_file;

        p = xdr_reserve_space(xdr, 8); /* eof flag and byte count */
        if (!p) {
                WARN_ON_ONCE(splice_ok);
                return nfserr_resource;
        }
        if (resp->xdr->buf->page_len && splice_ok) {
                WARN_ON_ONCE(1);
                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, file, maxcount);
        if (nfserr) {
                xdr_truncate_encode(xdr, starting_len);
                return nfserr;
        }

        p = xdr_encode_bool(p, read->rd_eof);
        *p = cpu_to_be32(read->rd_length);
        return nfs_ok;
}

static __be32
nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readlink *readlink)
{
        __be32 *p, *maxcount_p, zero = xdr_zero;
        struct xdr_stream *xdr = resp->xdr;
        int length_offset = xdr->buf->len;
        int maxcount, status;

        maxcount_p = xdr_reserve_space(xdr, XDR_UNIT);
        if (!maxcount_p)
                return nfserr_resource;
        maxcount = PAGE_SIZE;

        p = xdr_reserve_space(xdr, maxcount);
        if (!p)
                return nfserr_resource;
        /*
         * XXX: By default, vfs_readlink() will truncate symlinks if they
         * would overflow the buffer.  Is this kosher in NFSv4?  If not, one
         * easy fix is: if vfs_readlink() precisely fills the buffer, assume
         * that truncation occurred, and return NFS4ERR_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;
        }
        *maxcount_p = cpu_to_be32(maxcount);
        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_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readdir *readdir)
{
        int maxcount;
        int bytes_left;
        loff_t offset;
        __be64 wire_offset;
        struct xdr_stream *xdr = resp->xdr;
        int starting_len = xdr->buf->len;
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
        if (!p)
                return nfserr_resource;

        /* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
        *p++ = cpu_to_be32(0);
        *p++ = cpu_to_be32(0);
        xdr->buf->head[0].iov_len = (char *)xdr->p -
                                    (char *)xdr->buf->head[0].iov_base;

        /*
         * 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 - 8;
        if (bytes_left < 0) {
                nfserr = nfserr_resource;
                goto err_no_verf;
        }
        maxcount = svc_max_payload(resp->rqstp);
        maxcount = min_t(u32, readdir->rd_maxcount, maxcount);
        /*
         * Note the rfc defines rd_maxcount as the size of the
         * READDIR4resok structure, which includes the verifier above
         * and the 8 bytes encoded at the end of this function:
         */
        if (maxcount < 16) {
                nfserr = nfserr_toosmall;
                goto err_no_verf;
        }
        maxcount = min_t(int, maxcount-16, bytes_left);

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

        readdir->xdr = xdr;
        readdir->rd_maxcount = maxcount;
        readdir->common.err = 0;
        readdir->cookie_offset = 0;

        offset = readdir->rd_cookie;
        nfserr = nfsd_readdir(readdir->rd_rqstp, readdir->rd_fhp,
                              &offset,
                              &readdir->common, nfsd4_encode_dirent);
        if (nfserr == nfs_ok &&
            readdir->common.err == nfserr_toosmall &&
            xdr->buf->len == starting_len + 8) {
                /* nothing encoded; which limit did we hit?: */
                if (maxcount - 16 < bytes_left)
                        /* It was the fault of rd_maxcount: */
                        nfserr = nfserr_toosmall;
                else
                        /* We ran out of buffer space: */
                        nfserr = nfserr_resource;
        }
        if (nfserr)
                goto err_no_verf;

        if (readdir->cookie_offset) {
                wire_offset = cpu_to_be64(offset);
                write_bytes_to_xdr_buf(xdr->buf, readdir->cookie_offset,
                                                        &wire_offset, 8);
        }

        p = xdr_reserve_space(xdr, 8);
        if (!p) {
                WARN_ON_ONCE(1);
                goto err_no_verf;
        }
        *p++ = 0;       /* no more entries */
        *p++ = htonl(readdir->common.err == nfserr_eof);

        return 0;
err_no_verf:
        xdr_truncate_encode(xdr, starting_len);
        return nfserr;
}

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

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return nfserr_resource;
        p = encode_cinfo(p, &remove->rm_cinfo);
        return 0;
}

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

        p = xdr_reserve_space(xdr, 40);
        if (!p)
                return nfserr_resource;
        p = encode_cinfo(p, &rename->rn_sinfo);
        p = encode_cinfo(p, &rename->rn_tinfo);
        return 0;
}

static __be32
nfsd4_do_encode_secinfo(struct xdr_stream *xdr, struct svc_export *exp)
{
        u32 i, nflavs, supported;
        struct exp_flavor_info *flavs;
        struct exp_flavor_info def_flavs[2];
        __be32 *p, *flavorsp;
        static bool report = true;

        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;
                }
        }

        supported = 0;
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        flavorsp = p++;         /* to be backfilled later */

        for (i = 0; i < nflavs; i++) {
                rpc_authflavor_t pf = flavs[i].pseudoflavor;
                struct rpcsec_gss_info info;

                if (rpcauth_get_gssinfo(pf, &info) == 0) {
                        supported++;
                        p = xdr_reserve_space(xdr, 4 + 4 +
                                              XDR_LEN(info.oid.len) + 4 + 4);
                        if (!p)
                                return nfserr_resource;
                        *p++ = cpu_to_be32(RPC_AUTH_GSS);
                        p = xdr_encode_opaque(p,  info.oid.data, info.oid.len);
                        *p++ = cpu_to_be32(info.qop);
                        *p++ = cpu_to_be32(info.service);
                } else if (pf < RPC_AUTH_MAXFLAVOR) {
                        supported++;
                        p = xdr_reserve_space(xdr, 4);
                        if (!p)
                                return nfserr_resource;
                        *p++ = cpu_to_be32(pf);
                } else {
                        if (report)
                                pr_warn("NFS: SECINFO: security flavor %u "
                                        "is not supported\n", pf);
                }
        }

        if (nflavs != supported)
                report = false;
        *flavorsp = htonl(supported);
        return 0;
}

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

        return nfsd4_do_encode_secinfo(xdr, secinfo->si_exp);
}

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

        return nfsd4_do_encode_secinfo(xdr, secinfo->sin_exp);
}

/*
 * The SETATTR encode routine is special -- it always encodes a bitmap,
 * regardless of the error status.
 */
static __be32
nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setattr *setattr)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 16);
        if (!p)
                return nfserr_resource;
        if (nfserr) {
                *p++ = cpu_to_be32(3);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);
        }
        else {
                *p++ = cpu_to_be32(3);
                *p++ = cpu_to_be32(setattr->sa_bmval[0]);
                *p++ = cpu_to_be32(setattr->sa_bmval[1]);
                *p++ = cpu_to_be32(setattr->sa_bmval[2]);
        }
        return nfserr;
}

static __be32
nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        if (!nfserr) {
                p = xdr_reserve_space(xdr, 8 + NFS4_VERIFIER_SIZE);
                if (!p)
                        return nfserr_resource;
                p = xdr_encode_opaque_fixed(p, &scd->se_clientid, 8);
                p = xdr_encode_opaque_fixed(p, &scd->se_confirm,
                                                NFS4_VERIFIER_SIZE);
        }
        else if (nfserr == nfserr_clid_inuse) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(0);
                *p++ = cpu_to_be32(0);
        }
        return nfserr;
}

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

        p = xdr_reserve_space(xdr, 16);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(write->wr_bytes_written);
        *p++ = cpu_to_be32(write->wr_how_written);
        p = xdr_encode_opaque_fixed(p, write->wr_verifier.data,
                                                NFS4_VERIFIER_SIZE);
        return 0;
}

static __be32
nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
                         struct nfsd4_exchange_id *exid)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;
        char *major_id;
        char *server_scope;
        int major_id_sz;
        int server_scope_sz;
        uint64_t minor_id = 0;
        struct nfsd_net *nn = net_generic(SVC_NET(resp->rqstp), nfsd_net_id);

        major_id = nn->nfsd_name;
        major_id_sz = strlen(nn->nfsd_name);
        server_scope = nn->nfsd_name;
        server_scope_sz = strlen(nn->nfsd_name);

        p = xdr_reserve_space(xdr,
                8 /* eir_clientid */ +
                4 /* eir_sequenceid */ +
                4 /* eir_flags */ +
                4 /* spr_how */);
        if (!p)
                return nfserr_resource;

        p = xdr_encode_opaque_fixed(p, &exid->clientid, 8);
        *p++ = cpu_to_be32(exid->seqid);
        *p++ = cpu_to_be32(exid->flags);

        *p++ = cpu_to_be32(exid->spa_how);

        switch (exid->spa_how) {
        case SP4_NONE:
                break;
        case SP4_MACH_CRED:
                /* spo_must_enforce bitmap: */
                nfserr = nfsd4_encode_bitmap(xdr,
                                        exid->spo_must_enforce[0],
                                        exid->spo_must_enforce[1],
                                        exid->spo_must_enforce[2]);
                if (nfserr)
                        return nfserr;
                /* spo_must_allow bitmap: */
                nfserr = nfsd4_encode_bitmap(xdr,
                                        exid->spo_must_allow[0],
                                        exid->spo_must_allow[1],
                                        exid->spo_must_allow[2]);
                if (nfserr)
                        return nfserr;
                break;
        default:
                WARN_ON_ONCE(1);
        }

        p = xdr_reserve_space(xdr,
                8 /* so_minor_id */ +
                4 /* so_major_id.len */ +
                (XDR_QUADLEN(major_id_sz) * 4) +
                4 /* eir_server_scope.len */ +
                (XDR_QUADLEN(server_scope_sz) * 4) +
                4 /* eir_server_impl_id.count (0) */);
        if (!p)
                return nfserr_resource;

        /* The server_owner struct */
        p = xdr_encode_hyper(p, minor_id);      /* Minor id */
        /* major id */
        p = xdr_encode_opaque(p, major_id, major_id_sz);

        /* Server scope */
        p = xdr_encode_opaque(p, server_scope, server_scope_sz);

        /* Implementation id */
        *p++ = cpu_to_be32(0);  /* zero length nfs_impl_id4 array */
        return 0;
}

static __be32
nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
                            struct nfsd4_create_session *sess)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 24);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_opaque_fixed(p, sess->sessionid.data,
                                        NFS4_MAX_SESSIONID_LEN);
        *p++ = cpu_to_be32(sess->seqid);
        *p++ = cpu_to_be32(sess->flags);

        p = xdr_reserve_space(xdr, 28);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(0); /* headerpadsz */
        *p++ = cpu_to_be32(sess->fore_channel.maxreq_sz);
        *p++ = cpu_to_be32(sess->fore_channel.maxresp_sz);
        *p++ = cpu_to_be32(sess->fore_channel.maxresp_cached);
        *p++ = cpu_to_be32(sess->fore_channel.maxops);
        *p++ = cpu_to_be32(sess->fore_channel.maxreqs);
        *p++ = cpu_to_be32(sess->fore_channel.nr_rdma_attrs);

        if (sess->fore_channel.nr_rdma_attrs) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(sess->fore_channel.rdma_attrs);
        }

        p = xdr_reserve_space(xdr, 28);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(0); /* headerpadsz */
        *p++ = cpu_to_be32(sess->back_channel.maxreq_sz);
        *p++ = cpu_to_be32(sess->back_channel.maxresp_sz);
        *p++ = cpu_to_be32(sess->back_channel.maxresp_cached);
        *p++ = cpu_to_be32(sess->back_channel.maxops);
        *p++ = cpu_to_be32(sess->back_channel.maxreqs);
        *p++ = cpu_to_be32(sess->back_channel.nr_rdma_attrs);

        if (sess->back_channel.nr_rdma_attrs) {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(sess->back_channel.rdma_attrs);
        }
        return 0;
}

static __be32
nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
                      struct nfsd4_sequence *seq)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 20);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_opaque_fixed(p, seq->sessionid.data,
                                        NFS4_MAX_SESSIONID_LEN);
        *p++ = cpu_to_be32(seq->seqid);
        *p++ = cpu_to_be32(seq->slotid);
        /* Note slotid's are numbered from zero: */
        *p++ = cpu_to_be32(seq->maxslots - 1); /* sr_highest_slotid */
        *p++ = cpu_to_be32(seq->maxslots - 1); /* sr_target_highest_slotid */
        *p++ = cpu_to_be32(seq->status_flags);

        resp->cstate.data_offset = xdr->buf->len; /* DRC cache data pointer */
        return 0;
}

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

        p = xdr_reserve_space(xdr, 4 + (4 * test_stateid->ts_num_ids));
        if (!p)
                return nfserr_resource;
        *p++ = htonl(test_stateid->ts_num_ids);

        list_for_each_entry_safe(stateid, next, &test_stateid->ts_stateid_list, ts_id_list) {
                *p++ = stateid->ts_id_status;
        }

        return 0;
}

#ifdef CONFIG_NFSD_PNFS
static __be32
nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
                struct nfsd4_getdeviceinfo *gdev)
{
        struct xdr_stream *xdr = resp->xdr;
        const struct nfsd4_layout_ops *ops;
        u32 starting_len = xdr->buf->len, needed_len;
        __be32 *p;

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

        *p++ = cpu_to_be32(gdev->gd_layout_type);

        /* If maxcount is 0 then just update notifications */
        if (gdev->gd_maxcount != 0) {
                ops = nfsd4_layout_ops[gdev->gd_layout_type];
                nfserr = ops->encode_getdeviceinfo(xdr, gdev);
                if (nfserr) {
                        /*
                         * We don't bother to 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 + 4 > gdev->gd_maxcount)
                                goto toosmall;
                        return nfserr;
                }
        }

        if (gdev->gd_notify_types) {
                p = xdr_reserve_space(xdr, 4 + 4);
                if (!p)
                        return nfserr_resource;
                *p++ = cpu_to_be32(1);                  /* bitmap length */
                *p++ = cpu_to_be32(gdev->gd_notify_types);
        } else {
                p = xdr_reserve_space(xdr, 4);
                if (!p)
                        return nfserr_resource;
                *p++ = 0;
        }

        return 0;
toosmall:
        dprintk("%s: maxcount too small\n", __func__);
        needed_len = xdr->buf->len + 4 /* notifications */;
        xdr_truncate_encode(xdr, starting_len);
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(needed_len);
        return nfserr_toosmall;
}

static __be32
nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr,
                struct nfsd4_layoutget *lgp)
{
        struct xdr_stream *xdr = resp->xdr;
        const struct nfsd4_layout_ops *ops;
        __be32 *p;

        p = xdr_reserve_space(xdr, 36 + sizeof(stateid_opaque_t));
        if (!p)
                return nfserr_resource;

        *p++ = cpu_to_be32(1);  /* we always set return-on-close */
        *p++ = cpu_to_be32(lgp->lg_sid.si_generation);
        p = xdr_encode_opaque_fixed(p, &lgp->lg_sid.si_opaque,
                                    sizeof(stateid_opaque_t));

        *p++ = cpu_to_be32(1);  /* we always return a single layout */
        p = xdr_encode_hyper(p, lgp->lg_seg.offset);
        p = xdr_encode_hyper(p, lgp->lg_seg.length);
        *p++ = cpu_to_be32(lgp->lg_seg.iomode);
        *p++ = cpu_to_be32(lgp->lg_layout_type);

        ops = nfsd4_layout_ops[lgp->lg_layout_type];
        return ops->encode_layoutget(xdr, lgp);
}

static __be32
nfsd4_encode_layoutcommit(struct nfsd4_compoundres *resp, __be32 nfserr,
                          struct nfsd4_layoutcommit *lcp)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(lcp->lc_size_chg);
        if (lcp->lc_size_chg) {
                p = xdr_reserve_space(xdr, 8);
                if (!p)
                        return nfserr_resource;
                p = xdr_encode_hyper(p, lcp->lc_newsize);
        }

        return 0;
}

static __be32
nfsd4_encode_layoutreturn(struct nfsd4_compoundres *resp, __be32 nfserr,
                struct nfsd4_layoutreturn *lrp)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;
        *p++ = cpu_to_be32(lrp->lrs_present);
        if (lrp->lrs_present)
                return nfsd4_encode_stateid(xdr, &lrp->lr_sid);
        return 0;
}
#endif /* CONFIG_NFSD_PNFS */

static __be32
nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
                struct nfsd42_write_res *write, bool sync)
{
        __be32 *p;
        p = xdr_reserve_space(resp->xdr, 4);
        if (!p)
                return nfserr_resource;

        if (sync)
                *p++ = cpu_to_be32(0);
        else {
                __be32 nfserr;
                *p++ = cpu_to_be32(1);
                nfserr = nfsd4_encode_stateid(resp->xdr, &write->cb_stateid);
                if (nfserr)
                        return nfserr;
        }
        p = xdr_reserve_space(resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
        if (!p)
                return nfserr_resource;

        p = xdr_encode_hyper(p, write->wr_bytes_written);
        *p++ = cpu_to_be32(write->wr_stable_how);
        p = xdr_encode_opaque_fixed(p, write->wr_verifier.data,
                                    NFS4_VERIFIER_SIZE);
        return nfs_ok;
}

static __be32
nfsd42_encode_nl4_server(struct nfsd4_compoundres *resp, struct nl4_server *ns)
{
        struct xdr_stream *xdr = resp->xdr;
        struct nfs42_netaddr *addr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 4);
        *p++ = cpu_to_be32(ns->nl4_type);

        switch (ns->nl4_type) {
        case NL4_NETADDR:
                addr = &ns->u.nl4_addr;

                /* netid_len, netid, uaddr_len, uaddr (port included
                 * in RPCBIND_MAXUADDRLEN)
                 */
                p = xdr_reserve_space(xdr,
                        4 /* netid len */ +
                        (XDR_QUADLEN(addr->netid_len) * 4) +
                        4 /* uaddr len */ +
                        (XDR_QUADLEN(addr->addr_len) * 4));
                if (!p)
                        return nfserr_resource;

                *p++ = cpu_to_be32(addr->netid_len);
                p = xdr_encode_opaque_fixed(p, addr->netid,
                                            addr->netid_len);
                *p++ = cpu_to_be32(addr->addr_len);
                p = xdr_encode_opaque_fixed(p, addr->addr,
                                        addr->addr_len);
                break;
        default:
                WARN_ON_ONCE(ns->nl4_type != NL4_NETADDR);
                return nfserr_inval;
        }

        return 0;
}

static __be32
nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
                  struct nfsd4_copy *copy)
{
        __be32 *p;

        nfserr = nfsd42_encode_write_res(resp, &copy->cp_res,
                                         nfsd4_copy_is_sync(copy));
        if (nfserr)
                return nfserr;

        p = xdr_reserve_space(resp->xdr, 4 + 4);
        *p++ = xdr_one; /* cr_consecutive */
        *p = nfsd4_copy_is_sync(copy) ? xdr_one : xdr_zero;
        return 0;
}

static __be32
nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
                            struct nfsd4_offload_status *os)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 8 + 4);
        if (!p)
                return nfserr_resource;
        p = xdr_encode_hyper(p, os->count);
        *p++ = cpu_to_be32(0);
        return nfserr;
}

static __be32
nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
                            struct nfsd4_read *read,
                            unsigned long *maxcount, u32 *eof,
                            loff_t *pos)
{
        struct xdr_stream *xdr = resp->xdr;
        struct file *file = read->rd_nf->nf_file;
        int starting_len = xdr->buf->len;
        loff_t hole_pos;
        __be32 nfserr;
        __be32 *p, tmp;
        __be64 tmp64;

        hole_pos = pos ? *pos : vfs_llseek(file, read->rd_offset, SEEK_HOLE);
        if (hole_pos > read->rd_offset)
                *maxcount = min_t(unsigned long, *maxcount, hole_pos - read->rd_offset);
        *maxcount = min_t(unsigned long, *maxcount, (xdr->buf->buflen - xdr->buf->len));

        /* Content type, offset, byte count */
        p = xdr_reserve_space(xdr, 4 + 8 + 4);
        if (!p)
                return nfserr_resource;

        read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, *maxcount);
        if (read->rd_vlen < 0)
                return nfserr_resource;

        nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
                            resp->rqstp->rq_vec, read->rd_vlen, maxcount, eof);
        if (nfserr)
                return nfserr;
        xdr_truncate_encode(xdr, starting_len + 16 + xdr_align_size(*maxcount));

        tmp = htonl(NFS4_CONTENT_DATA);
        write_bytes_to_xdr_buf(xdr->buf, starting_len,      &tmp,   4);
        tmp64 = cpu_to_be64(read->rd_offset);
        write_bytes_to_xdr_buf(xdr->buf, starting_len + 4,  &tmp64, 8);
        tmp = htonl(*maxcount);
        write_bytes_to_xdr_buf(xdr->buf, starting_len + 12, &tmp,   4);

        tmp = xdr_zero;
        write_bytes_to_xdr_buf(xdr->buf, starting_len + 16 + *maxcount, &tmp,
                               xdr_pad_size(*maxcount));
        return nfs_ok;
}

static __be32
nfsd4_encode_read_plus_hole(struct nfsd4_compoundres *resp,
                            struct nfsd4_read *read,
                            unsigned long *maxcount, u32 *eof)
{
        struct file *file = read->rd_nf->nf_file;
        loff_t data_pos = vfs_llseek(file, read->rd_offset, SEEK_DATA);
        loff_t f_size = i_size_read(file_inode(file));
        unsigned long count;
        __be32 *p;

        if (data_pos == -ENXIO)
                data_pos = f_size;
        else if (data_pos <= read->rd_offset || (data_pos < f_size && data_pos % PAGE_SIZE))
                return nfsd4_encode_read_plus_data(resp, read, maxcount, eof, &f_size);
        count = data_pos - read->rd_offset;

        /* Content type, offset, byte count */
        p = xdr_reserve_space(resp->xdr, 4 + 8 + 8);
        if (!p)
                return nfserr_resource;

        *p++ = htonl(NFS4_CONTENT_HOLE);
        p = xdr_encode_hyper(p, read->rd_offset);
        p = xdr_encode_hyper(p, count);

        *eof = (read->rd_offset + count) >= f_size;
        *maxcount = min_t(unsigned long, count, *maxcount);
        return nfs_ok;
}

static __be32
nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
                       struct nfsd4_read *read)
{
        unsigned long maxcount, count;
        struct xdr_stream *xdr = resp->xdr;
        struct file *file;
        int starting_len = xdr->buf->len;
        int last_segment = xdr->buf->len;
        int segments = 0;
        __be32 *p, tmp;
        bool is_data;
        loff_t pos;
        u32 eof;

        if (nfserr)
                return nfserr;
        file = read->rd_nf->nf_file;

        /* eof flag, segment count */
        p = xdr_reserve_space(xdr, 4 + 4);
        if (!p)
                return nfserr_resource;
        xdr_commit_encode(xdr);

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

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

        pos = vfs_llseek(file, read->rd_offset, SEEK_HOLE);
        is_data = pos > read->rd_offset;

        while (count > 0 && !eof) {
                maxcount = count;
                if (is_data)
                        nfserr = nfsd4_encode_read_plus_data(resp, read, &maxcount, &eof,
                                                segments == 0 ? &pos : NULL);
                else
                        nfserr = nfsd4_encode_read_plus_hole(resp, read, &maxcount, &eof);
                if (nfserr)
                        goto out;
                count -= maxcount;
                read->rd_offset += maxcount;
                is_data = !is_data;
                last_segment = xdr->buf->len;
                segments++;
        }

out:
        if (nfserr && segments == 0)
                xdr_truncate_encode(xdr, starting_len);
        else {
                if (nfserr) {
                        xdr_truncate_encode(xdr, last_segment);
                        nfserr = nfs_ok;
                        eof = 0;
                }
                tmp = htonl(eof);
                write_bytes_to_xdr_buf(xdr->buf, starting_len,     &tmp, 4);
                tmp = htonl(segments);
                write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
        }

        return nfserr;
}

static __be32
nfsd4_encode_copy_notify(struct nfsd4_compoundres *resp, __be32 nfserr,
                         struct nfsd4_copy_notify *cn)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        if (nfserr)
                return nfserr;

        /* 8 sec, 4 nsec */
        p = xdr_reserve_space(xdr, 12);
        if (!p)
                return nfserr_resource;

        /* cnr_lease_time */
        p = xdr_encode_hyper(p, cn->cpn_sec);
        *p++ = cpu_to_be32(cn->cpn_nsec);

        /* cnr_stateid */
        nfserr = nfsd4_encode_stateid(xdr, &cn->cpn_cnr_stateid);
        if (nfserr)
                return nfserr;

        /* cnr_src.nl_nsvr */
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                return nfserr_resource;

        *p++ = cpu_to_be32(1);

        nfserr = nfsd42_encode_nl4_server(resp, cn->cpn_src);
        return nfserr;
}

static __be32
nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
                  struct nfsd4_seek *seek)
{
        __be32 *p;

        p = xdr_reserve_space(resp->xdr, 4 + 8);
        *p++ = cpu_to_be32(seek->seek_eof);
        p = xdr_encode_hyper(p, seek->seek_pos);

        return 0;
}

static __be32
nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *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,
                      struct nfsd4_getxattr *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,
                      struct nfsd4_setxattr *setxattr)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return nfserr_resource;

        encode_cinfo(p, &setxattr->setxa_cinfo);

        return 0;
}

/*
 * 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 either the buffer we just got back from vfs_listxattr, or,
         * XDR-encoded, in the return buffer, it's invalid.
         */
        if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
                return nfserr_badcookie;

        if (cookie > (listxattrs->lsxa_maxcount /
                      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
                return nfserr_badcookie;

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

static __be32
nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
                        struct nfsd4_listxattrs *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;
        __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, 12);
        if (!p) {
                status = nfserr_resource;
                goto out;
        }

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

        xdrleft = listxattrs->lsxa_maxcount;

        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);
                if (xdrlen > 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;

        write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &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,
                         struct nfsd4_removexattr *removexattr)
{
        struct xdr_stream *xdr = resp->xdr;
        __be32 *p;

        p = xdr_reserve_space(xdr, 20);
        if (!p)
                return nfserr_resource;

        p = encode_cinfo(p, &removexattr->rmxa_cinfo);
        return 0;
}

typedef __be32(* nfsd4_enc)(struct nfsd4_compoundres *, __be32, void *);

/*
 * 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_enc)nfsd4_encode_access,
        [OP_CLOSE]              = (nfsd4_enc)nfsd4_encode_close,
        [OP_COMMIT]             = (nfsd4_enc)nfsd4_encode_commit,
        [OP_CREATE]             = (nfsd4_enc)nfsd4_encode_create,
        [OP_DELEGPURGE]         = (nfsd4_enc)nfsd4_encode_noop,
        [OP_DELEGRETURN]        = (nfsd4_enc)nfsd4_encode_noop,
        [OP_GETATTR]            = (nfsd4_enc)nfsd4_encode_getattr,
        [OP_GETFH]              = (nfsd4_enc)nfsd4_encode_getfh,
        [OP_LINK]               = (nfsd4_enc)nfsd4_encode_link,
        [OP_LOCK]               = (nfsd4_enc)nfsd4_encode_lock,
        [OP_LOCKT]              = (nfsd4_enc)nfsd4_encode_lockt,
        [OP_LOCKU]              = (nfsd4_enc)nfsd4_encode_locku,
        [OP_LOOKUP]             = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LOOKUPP]            = (nfsd4_enc)nfsd4_encode_noop,
        [OP_NVERIFY]            = (nfsd4_enc)nfsd4_encode_noop,
        [OP_OPEN]               = (nfsd4_enc)nfsd4_encode_open,
        [OP_OPENATTR]           = (nfsd4_enc)nfsd4_encode_noop,
        [OP_OPEN_CONFIRM]       = (nfsd4_enc)nfsd4_encode_open_confirm,
        [OP_OPEN_DOWNGRADE]     = (nfsd4_enc)nfsd4_encode_open_downgrade,
        [OP_PUTFH]              = (nfsd4_enc)nfsd4_encode_noop,
        [OP_PUTPUBFH]           = (nfsd4_enc)nfsd4_encode_noop,
        [OP_PUTROOTFH]          = (nfsd4_enc)nfsd4_encode_noop,
        [OP_READ]               = (nfsd4_enc)nfsd4_encode_read,
        [OP_READDIR]            = (nfsd4_enc)nfsd4_encode_readdir,
        [OP_READLINK]           = (nfsd4_enc)nfsd4_encode_readlink,
        [OP_REMOVE]             = (nfsd4_enc)nfsd4_encode_remove,
        [OP_RENAME]             = (nfsd4_enc)nfsd4_encode_rename,
        [OP_RENEW]              = (nfsd4_enc)nfsd4_encode_noop,
        [OP_RESTOREFH]          = (nfsd4_enc)nfsd4_encode_noop,
        [OP_SAVEFH]             = (nfsd4_enc)nfsd4_encode_noop,
        [OP_SECINFO]            = (nfsd4_enc)nfsd4_encode_secinfo,
        [OP_SETATTR]            = (nfsd4_enc)nfsd4_encode_setattr,
        [OP_SETCLIENTID]        = (nfsd4_enc)nfsd4_encode_setclientid,
        [OP_SETCLIENTID_CONFIRM] = (nfsd4_enc)nfsd4_encode_noop,
        [OP_VERIFY]             = (nfsd4_enc)nfsd4_encode_noop,
        [OP_WRITE]              = (nfsd4_enc)nfsd4_encode_write,
        [OP_RELEASE_LOCKOWNER]  = (nfsd4_enc)nfsd4_encode_noop,

        /* NFSv4.1 operations */
        [OP_BACKCHANNEL_CTL]    = (nfsd4_enc)nfsd4_encode_noop,
        [OP_BIND_CONN_TO_SESSION] = (nfsd4_enc)nfsd4_encode_bind_conn_to_session,
        [OP_EXCHANGE_ID]        = (nfsd4_enc)nfsd4_encode_exchange_id,
        [OP_CREATE_SESSION]     = (nfsd4_enc)nfsd4_encode_create_session,
        [OP_DESTROY_SESSION]    = (nfsd4_enc)nfsd4_encode_noop,
        [OP_FREE_STATEID]       = (nfsd4_enc)nfsd4_encode_noop,
        [OP_GET_DIR_DELEGATION] = (nfsd4_enc)nfsd4_encode_noop,
#ifdef CONFIG_NFSD_PNFS
        [OP_GETDEVICEINFO]      = (nfsd4_enc)nfsd4_encode_getdeviceinfo,
        [OP_GETDEVICELIST]      = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTCOMMIT]       = (nfsd4_enc)nfsd4_encode_layoutcommit,
        [OP_LAYOUTGET]          = (nfsd4_enc)nfsd4_encode_layoutget,
        [OP_LAYOUTRETURN]       = (nfsd4_enc)nfsd4_encode_layoutreturn,
#else
        [OP_GETDEVICEINFO]      = (nfsd4_enc)nfsd4_encode_noop,
        [OP_GETDEVICELIST]      = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTCOMMIT]       = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTGET]          = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTRETURN]       = (nfsd4_enc)nfsd4_encode_noop,
#endif
        [OP_SECINFO_NO_NAME]    = (nfsd4_enc)nfsd4_encode_secinfo_no_name,
        [OP_SEQUENCE]           = (nfsd4_enc)nfsd4_encode_sequence,
        [OP_SET_SSV]            = (nfsd4_enc)nfsd4_encode_noop,
        [OP_TEST_STATEID]       = (nfsd4_enc)nfsd4_encode_test_stateid,
        [OP_WANT_DELEGATION]    = (nfsd4_enc)nfsd4_encode_noop,
        [OP_DESTROY_CLIENTID]   = (nfsd4_enc)nfsd4_encode_noop,
        [OP_RECLAIM_COMPLETE]   = (nfsd4_enc)nfsd4_encode_noop,

        /* NFSv4.2 operations */
        [OP_ALLOCATE]           = (nfsd4_enc)nfsd4_encode_noop,
        [OP_COPY]               = (nfsd4_enc)nfsd4_encode_copy,
        [OP_COPY_NOTIFY]        = (nfsd4_enc)nfsd4_encode_copy_notify,
        [OP_DEALLOCATE]         = (nfsd4_enc)nfsd4_encode_noop,
        [OP_IO_ADVISE]          = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTERROR]        = (nfsd4_enc)nfsd4_encode_noop,
        [OP_LAYOUTSTATS]        = (nfsd4_enc)nfsd4_encode_noop,
        [OP_OFFLOAD_CANCEL]     = (nfsd4_enc)nfsd4_encode_noop,
        [OP_OFFLOAD_STATUS]     = (nfsd4_enc)nfsd4_encode_offload_status,
        [OP_READ_PLUS]          = (nfsd4_enc)nfsd4_encode_read_plus,
        [OP_SEEK]               = (nfsd4_enc)nfsd4_encode_seek,
        [OP_WRITE_SAME]         = (nfsd4_enc)nfsd4_encode_noop,
        [OP_CLONE]              = (nfsd4_enc)nfsd4_encode_noop,

        /* RFC 8276 extended atributes operations */
        [OP_GETXATTR]           = (nfsd4_enc)nfsd4_encode_getxattr,
        [OP_SETXATTR]           = (nfsd4_enc)nfsd4_encode_setxattr,
        [OP_LISTXATTRS]         = (nfsd4_enc)nfsd4_encode_listxattrs,
        [OP_REMOVEXATTR]        = (nfsd4_enc)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;
}

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;
        int post_err_offset;
        nfsd4_enc encoder;
        __be32 *p;

        p = xdr_reserve_space(xdr, 8);
        if (!p) {
                WARN_ON_ONCE(1);
                return;
        }
        *p++ = cpu_to_be32(op->opnum);
        post_err_offset = xdr->buf->len;

        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);
        if (opdesc && opdesc->op_release)
                opdesc->op_release(&op->u);
        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, post_err_offset);
        }
        if (so) {
                int len = xdr->buf->len - post_err_offset;

                so->so_replay.rp_status = op->status;
                so->so_replay.rp_buflen = len;
                read_bytes_from_xdr_buf(xdr->buf, post_err_offset,
                                                so->so_replay.rp_buf, len);
        }
status:
        *p = op->status;
}

/* 
 * Encode the reply stored in the stateowner reply cache 
 * 
 * XDR note: do not encode rp->rp_buflen: the buffer contains the
 * previously sent already encoded operation.
 */
void
nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op)
{
        __be32 *p;
        struct nfs4_replay *rp = op->replay;

        p = xdr_reserve_space(xdr, 8 + rp->rp_buflen);
        if (!p) {
                WARN_ON_ONCE(1);
                return;
        }
        *p++ = cpu_to_be32(op->opnum);
        *p++ = rp->rp_status;  /* already xdr'ed */

        p = xdr_encode_opaque_fixed(p, 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) {
                kfree(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;

        return nfsd4_decode_compound(args);
}

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

        WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
                                 buf->tail[0].iov_len);

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

        *p++ = resp->cstate.status;

        rqstp->rq_next_page = xdr->page_ptr + 1;

        *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;
}