/*
 *  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_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 nfserrno(-ENOMEM);       /* XXX: not 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)
{
        struct nl4_server *ns_dummy;
        u32 consecutive, i, count;
        __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_u32(argp->xdr, &copy->cp_synchronous) < 0)
                return nfserr_bad_xdr;

        if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
                return nfserr_bad_xdr;
        copy->cp_intra = false;
        if (count == 0) { /* intra-server copy */
                copy->cp_intra = true;
                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 nfserrno(-ENOMEM);       /* XXX: 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;

        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;
        int starting_len = xdr->buf->len;
        int attrlen_offset;
        __be32 attrlen;
        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;
        p = xdr_reserve_space(xdr, 4);
        if (!p)
                goto out_resource;
        p++;                /* to be backfilled later */

        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);