/*
 *  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.
 *
 * TODO: Neil Brown made the following observation:  We currently
 * initially reserve NFSD_BUFSIZE space on the transmit queue and
 * never release any of that until the request is complete.
 * It would be good to calculate a new maximum response size while
 * decoding the COMPOUND, and call svc_reserve with this number
 * at the end of nfs4svc_decode_compoundargs.
 */

#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/utsname.h>
#include <linux/sunrpc/svcauth_gss.h>

#include "idmap.h"
#include "acl.h"
#include "xdr4.h"
#include "vfs.h"


#define NFSDDBG_FACILITY                NFSDDBG_XDR

/*
 * 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, __be32 err)
{
        int i;

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

#define DECODE_HEAD                             \
        __be32 *p;                              \
        __be32 status
#define DECODE_TAIL                             \
        status = 0;                             \
out:                                            \
        return status;                          \
xdr_error:                                      \
        dprintk("NFSD: xdr error (%s:%d)\n",    \
                        __FILE__, __LINE__);    \
        status = nfserr_bad_xdr;                \
        goto out

#define READ32(x)         (x) = ntohl(*p++)
#define READ64(x)         do {                  \
        (x) = (u64)ntohl(*p++) << 32;           \
        (x) |= ntohl(*p++);                     \
} while (0)
#define READTIME(x)       do {                  \
        p++;                                    \
        (x) = ntohl(*p++);                      \
        p++;                                    \
} while (0)
#define READMEM(x,nbytes) do {                  \
        x = (char *)p;                          \
        p += XDR_QUADLEN(nbytes);               \
} while (0)
#define SAVEMEM(x,nbytes) do {                  \
        if (!(x = (p==argp->tmp || p == argp->tmpp) ? \
                savemem(argp, p, nbytes) :      \
                (char *)p)) {                   \
                dprintk("NFSD: xdr error (%s:%d)\n", \
                                __FILE__, __LINE__); \
                goto xdr_error;                 \
                }                               \
        p += XDR_QUADLEN(nbytes);               \
} while (0)
#define COPYMEM(x,nbytes) do {                  \
        memcpy((x), p, nbytes);                 \
        p += XDR_QUADLEN(nbytes);               \
} while (0)

/* READ_BUF, read_buf(): nbytes must be <= PAGE_SIZE */
#define READ_BUF(nbytes)  do {                  \
        if (nbytes <= (u32)((char *)argp->end - (char *)argp->p)) {     \
                p = argp->p;                    \
                argp->p += XDR_QUADLEN(nbytes); \
        } else if (!(p = read_buf(argp, nbytes))) { \
                dprintk("NFSD: xdr error (%s:%d)\n", \
                                __FILE__, __LINE__); \
                goto xdr_error;                 \
        }                                       \
} while (0)

static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
{
        /* We want more bytes than seem to be available.
         * Maybe we need a new page, maybe we have just run out
         */
        unsigned int avail = (char *)argp->end - (char *)argp->p;
        __be32 *p;
        if (avail + argp->pagelen < nbytes)
                return NULL;
        if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */
                return NULL;
        /* ok, we can do it with the current plus the next page */
        if (nbytes <= sizeof(argp->tmp))
                p = argp->tmp;
        else {
                kfree(argp->tmpp);
                p = argp->tmpp = kmalloc(nbytes, GFP_KERNEL);
                if (!p)
                        return NULL;
                
        }
        /*
         * The following memcpy is safe because read_buf is always
         * called with nbytes > avail, and the two cases above both
         * guarantee p points to at least nbytes bytes.
         */
        memcpy(p, argp->p, avail);
        /* step to next page */
        argp->p = page_address(argp->pagelist[0]);
        argp->pagelist++;
        if (argp->pagelen < PAGE_SIZE) {
                argp->end = argp->p + (argp->pagelen>>2);
                argp->pagelen = 0;
        } else {
                argp->end = argp->p + (PAGE_SIZE>>2);
                argp->pagelen -= PAGE_SIZE;
        }
        memcpy(((char*)p)+avail, argp->p, (nbytes - avail));
        argp->p += XDR_QUADLEN(nbytes - avail);
        return p;
}

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

static int
defer_free(struct nfsd4_compoundargs *argp,
                void (*release)(const void *), void *p)
{
        struct tmpbuf *tb;

        tb = kmalloc(sizeof(*tb), GFP_KERNEL);
        if (!tb)
                return -ENOMEM;
        tb->buf = p;
        tb->release = release;
        tb->next = argp->to_free;
        argp->to_free = tb;
        return 0;
}

static char *savemem(struct nfsd4_compoundargs *argp, __be32 *p, int nbytes)
{
        if (p == argp->tmp) {
                p = kmalloc(nbytes, GFP_KERNEL);
                if (!p)
                        return NULL;
                memcpy(p, argp->tmp, nbytes);
        } else {
                BUG_ON(p != argp->tmpp);
                argp->tmpp = NULL;
        }
        if (defer_free(argp, kfree, p)) {
                kfree(p);
                return NULL;
        } else
                return (char *)p;
}

static __be32
nfsd4_decode_bitmap(struct nfsd4_compoundargs *argp, u32 *bmval)
{
        u32 bmlen;
        DECODE_HEAD;

        bmval[0] = 0;
        bmval[1] = 0;
        bmval[2] = 0;

        READ_BUF(4);
        READ32(bmlen);
        if (bmlen > 1000)
                goto xdr_error;

        READ_BUF(bmlen << 2);
        if (bmlen > 0)
                READ32(bmval[0]);
        if (bmlen > 1)
                READ32(bmval[1]);
        if (bmlen > 2)
                READ32(bmval[2]);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
                   struct iattr *iattr, struct nfs4_acl **acl)
{
        int expected_len, len = 0;
        u32 dummy32;
        char *buf;
        int host_err;

        DECODE_HEAD;
        iattr->ia_valid = 0;
        if ((status = nfsd4_decode_bitmap(argp, bmval)))
                return status;

        READ_BUF(4);
        READ32(expected_len);

        if (bmval[0] & FATTR4_WORD0_SIZE) {
                READ_BUF(8);
                len += 8;
                READ64(iattr->ia_size);
                iattr->ia_valid |= ATTR_SIZE;
        }
        if (bmval[0] & FATTR4_WORD0_ACL) {
                int nace;
                struct nfs4_ace *ace;

                READ_BUF(4); len += 4;
                READ32(nace);

                if (nace > NFS4_ACL_MAX)
                        return nfserr_resource;

                *acl = nfs4_acl_new(nace);
                if (*acl == NULL) {
                        host_err = -ENOMEM;
                        goto out_nfserr;
                }
                defer_free(argp, kfree, *acl);

                (*acl)->naces = nace;
                for (ace = (*acl)->aces; ace < (*acl)->aces + nace; ace++) {
                        READ_BUF(16); len += 16;
                        READ32(ace->type);
                        READ32(ace->flag);
                        READ32(ace->access_mask);
                        READ32(dummy32);
                        READ_BUF(dummy32);
                        len += XDR_QUADLEN(dummy32) << 2;
                        READMEM(buf, dummy32);
                        ace->whotype = nfs4_acl_get_whotype(buf, dummy32);
                        status = nfs_ok;
                        if (ace->whotype != NFS4_ACL_WHO_NAMED)
                                ace->who = 0;
                        else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                                status = nfsd_map_name_to_gid(argp->rqstp,
                                                buf, dummy32, &ace->who);
                        else
                                status = nfsd_map_name_to_uid(argp->rqstp,
                                                buf, dummy32, &ace->who);
                        if (status)
                                return status;
                }
        } else
                *acl = NULL;
        if (bmval[1] & FATTR4_WORD1_MODE) {
                READ_BUF(4);
                len += 4;
                READ32(iattr->ia_mode);
                iattr->ia_mode &= (S_IFMT | S_IALLUGO);
                iattr->ia_valid |= ATTR_MODE;
        }
        if (bmval[1] & FATTR4_WORD1_OWNER) {
                READ_BUF(4);
                len += 4;
                READ32(dummy32);
                READ_BUF(dummy32);
                len += (XDR_QUADLEN(dummy32) << 2);
                READMEM(buf, dummy32);
                if ((status = nfsd_map_name_to_uid(argp->rqstp, buf, dummy32, &iattr->ia_uid)))
                        return status;
                iattr->ia_valid |= ATTR_UID;
        }
        if (bmval[1] & FATTR4_WORD1_OWNER_GROUP) {
                READ_BUF(4);
                len += 4;
                READ32(dummy32);
                READ_BUF(dummy32);
                len += (XDR_QUADLEN(dummy32) << 2);
                READMEM(buf, dummy32);
                if ((status = nfsd_map_name_to_gid(argp->rqstp, buf, dummy32, &iattr->ia_gid)))
                        return status;
                iattr->ia_valid |= ATTR_GID;
        }
        if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
                READ_BUF(4);
                len += 4;
                READ32(dummy32);
                switch (dummy32) {
                case NFS4_SET_TO_CLIENT_TIME:
                        /* We require the high 32 bits of 'seconds' to be 0, and we ignore
                           all 32 bits of 'nseconds'. */
                        READ_BUF(12);
                        len += 12;
                        READ32(dummy32);
                        if (dummy32)
                                return nfserr_inval;
                        READ32(iattr->ia_atime.tv_sec);
                        READ32(iattr->ia_atime.tv_nsec);
                        if (iattr->ia_atime.tv_nsec >= (u32)1000000000)
                                return nfserr_inval;
                        iattr->ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
                        break;
                case NFS4_SET_TO_SERVER_TIME:
                        iattr->ia_valid |= ATTR_ATIME;
                        break;
                default:
                        goto xdr_error;
                }
        }
        if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
                READ_BUF(4);
                len += 4;
                READ32(dummy32);
                switch (dummy32) {
                case NFS4_SET_TO_CLIENT_TIME:
                        /* We require the high 32 bits of 'seconds' to be 0, and we ignore
                           all 32 bits of 'nseconds'. */
                        READ_BUF(12);
                        len += 12;
                        READ32(dummy32);
                        if (dummy32)
                                return nfserr_inval;
                        READ32(iattr->ia_mtime.tv_sec);
                        READ32(iattr->ia_mtime.tv_nsec);
                        if (iattr->ia_mtime.tv_nsec >= (u32)1000000000)
                                return nfserr_inval;
                        iattr->ia_valid |= (ATTR_MTIME | ATTR_MTIME_SET);
                        break;
                case NFS4_SET_TO_SERVER_TIME:
                        iattr->ia_valid |= ATTR_MTIME;
                        break;
                default:
                        goto xdr_error;
                }
        }
        if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
            || bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
            || bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2)
                READ_BUF(expected_len - len);
        else if (len != expected_len)
                goto xdr_error;

        DECODE_TAIL;

out_nfserr:
        status = nfserrno(host_err);
        goto out;
}

static __be32
nfsd4_decode_stateid(struct nfsd4_compoundargs *argp, stateid_t *sid)
{
        DECODE_HEAD;

        READ_BUF(sizeof(stateid_t));
        READ32(sid->si_generation);
        COPYMEM(&sid->si_opaque, sizeof(stateid_opaque_t));

        DECODE_TAIL;
}

static __be32
nfsd4_decode_access(struct nfsd4_compoundargs *argp, struct nfsd4_access *access)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(access->ac_req_access);

        DECODE_TAIL;
}

static __be32 nfsd4_decode_bind_conn_to_session(struct nfsd4_compoundargs *argp, struct nfsd4_bind_conn_to_session *bcts)
{
        DECODE_HEAD;

        READ_BUF(NFS4_MAX_SESSIONID_LEN + 8);
        COPYMEM(bcts->sessionid.data, NFS4_MAX_SESSIONID_LEN);
        READ32(bcts->dir);
        /* XXX: skipping ctsa_use_conn_in_rdma_mode.  Perhaps Tom Tucker
         * could help us figure out we should be using it. */
        DECODE_TAIL;
}

static __be32
nfsd4_decode_close(struct nfsd4_compoundargs *argp, struct nfsd4_close *close)
{
        DECODE_HEAD;

        close->cl_stateowner = NULL;
        READ_BUF(4);
        READ32(close->cl_seqid);
        return nfsd4_decode_stateid(argp, &close->cl_stateid);

        DECODE_TAIL;
}


static __be32
nfsd4_decode_commit(struct nfsd4_compoundargs *argp, struct nfsd4_commit *commit)
{
        DECODE_HEAD;

        READ_BUF(12);
        READ64(commit->co_offset);
        READ32(commit->co_count);

        DECODE_TAIL;
}

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

        READ_BUF(4);
        READ32(create->cr_type);
        switch (create->cr_type) {
        case NF4LNK:
                READ_BUF(4);
                READ32(create->cr_linklen);
                READ_BUF(create->cr_linklen);
                SAVEMEM(create->cr_linkname, create->cr_linklen);
                break;
        case NF4BLK:
        case NF4CHR:
                READ_BUF(8);
                READ32(create->cr_specdata1);
                READ32(create->cr_specdata2);
                break;
        case NF4SOCK:
        case NF4FIFO:
        case NF4DIR:
        default:
                break;
        }

        READ_BUF(4);
        READ32(create->cr_namelen);
        READ_BUF(create->cr_namelen);
        SAVEMEM(create->cr_name, create->cr_namelen);
        if ((status = check_filename(create->cr_name, create->cr_namelen, nfserr_inval)))
                return status;

        status = nfsd4_decode_fattr(argp, create->cr_bmval, &create->cr_iattr,
                                    &create->cr_acl);
        if (status)
                goto out;

        DECODE_TAIL;
}

static inline __be32
nfsd4_decode_delegreturn(struct nfsd4_compoundargs *argp, struct nfsd4_delegreturn *dr)
{
        return nfsd4_decode_stateid(argp, &dr->dr_stateid);
}

static inline __be32
nfsd4_decode_getattr(struct nfsd4_compoundargs *argp, struct nfsd4_getattr *getattr)
{
        return nfsd4_decode_bitmap(argp, getattr->ga_bmval);
}

static __be32
nfsd4_decode_link(struct nfsd4_compoundargs *argp, struct nfsd4_link *link)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(link->li_namelen);
        READ_BUF(link->li_namelen);
        SAVEMEM(link->li_name, link->li_namelen);
        if ((status = check_filename(link->li_name, link->li_namelen, nfserr_inval)))
                return status;

        DECODE_TAIL;
}

static __be32
nfsd4_decode_lock(struct nfsd4_compoundargs *argp, struct nfsd4_lock *lock)
{
        DECODE_HEAD;

        lock->lk_replay_owner = NULL;
        /*
        * type, reclaim(boolean), offset, length, new_lock_owner(boolean)
        */
        READ_BUF(28);
        READ32(lock->lk_type);
        if ((lock->lk_type < NFS4_READ_LT) || (lock->lk_type > NFS4_WRITEW_LT))
                goto xdr_error;
        READ32(lock->lk_reclaim);
        READ64(lock->lk_offset);
        READ64(lock->lk_length);
        READ32(lock->lk_is_new);

        if (lock->lk_is_new) {
                READ_BUF(4);
                READ32(lock->lk_new_open_seqid);
                status = nfsd4_decode_stateid(argp, &lock->lk_new_open_stateid);
                if (status)
                        return status;
                READ_BUF(8 + sizeof(clientid_t));
                READ32(lock->lk_new_lock_seqid);
                COPYMEM(&lock->lk_new_clientid, sizeof(clientid_t));
                READ32(lock->lk_new_owner.len);
                READ_BUF(lock->lk_new_owner.len);
                READMEM(lock->lk_new_owner.data, lock->lk_new_owner.len);
        } else {
                status = nfsd4_decode_stateid(argp, &lock->lk_old_lock_stateid);
                if (status)
                        return status;
                READ_BUF(4);
                READ32(lock->lk_old_lock_seqid);
        }

        DECODE_TAIL;
}

static __be32
nfsd4_decode_lockt(struct nfsd4_compoundargs *argp, struct nfsd4_lockt *lockt)
{
        DECODE_HEAD;
                        
        READ_BUF(32);
        READ32(lockt->lt_type);
        if((lockt->lt_type < NFS4_READ_LT) || (lockt->lt_type > NFS4_WRITEW_LT))
                goto xdr_error;
        READ64(lockt->lt_offset);
        READ64(lockt->lt_length);
        COPYMEM(&lockt->lt_clientid, 8);
        READ32(lockt->lt_owner.len);
        READ_BUF(lockt->lt_owner.len);
        READMEM(lockt->lt_owner.data, lockt->lt_owner.len);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_locku(struct nfsd4_compoundargs *argp, struct nfsd4_locku *locku)
{
        DECODE_HEAD;

        locku->lu_stateowner = NULL;
        READ_BUF(8);
        READ32(locku->lu_type);
        if ((locku->lu_type < NFS4_READ_LT) || (locku->lu_type > NFS4_WRITEW_LT))
                goto xdr_error;
        READ32(locku->lu_seqid);
        status = nfsd4_decode_stateid(argp, &locku->lu_stateid);
        if (status)
                return status;
        READ_BUF(16);
        READ64(locku->lu_offset);
        READ64(locku->lu_length);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_lookup(struct nfsd4_compoundargs *argp, struct nfsd4_lookup *lookup)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(lookup->lo_len);
        READ_BUF(lookup->lo_len);
        SAVEMEM(lookup->lo_name, lookup->lo_len);
        if ((status = check_filename(lookup->lo_name, lookup->lo_len, nfserr_noent)))
                return status;

        DECODE_TAIL;
}

static __be32
nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
{
        DECODE_HEAD;

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

        /* seqid, share_access, share_deny, clientid, ownerlen */
        READ_BUF(16 + sizeof(clientid_t));
        READ32(open->op_seqid);
        READ32(open->op_share_access);
        READ32(open->op_share_deny);
        COPYMEM(&open->op_clientid, sizeof(clientid_t));
        READ32(open->op_owner.len);

        /* owner, open_flag */
        READ_BUF(open->op_owner.len + 4);
        SAVEMEM(open->op_owner.data, open->op_owner.len);
        READ32(open->op_create);
        switch (open->op_create) {
        case NFS4_OPEN_NOCREATE:
                break;
        case NFS4_OPEN_CREATE:
                READ_BUF(4);
                READ32(open->op_createmode);
                switch (open->op_createmode) {
                case NFS4_CREATE_UNCHECKED:
                case NFS4_CREATE_GUARDED:
                        status = nfsd4_decode_fattr(argp, open->op_bmval,
                                &open->op_iattr, &open->op_acl);
                        if (status)
                                goto out;
                        break;
                case NFS4_CREATE_EXCLUSIVE:
                        READ_BUF(8);
                        COPYMEM(open->op_verf.data, 8);
                        break;
                case NFS4_CREATE_EXCLUSIVE4_1:
                        if (argp->minorversion < 1)
                                goto xdr_error;
                        READ_BUF(8);
                        COPYMEM(open->op_verf.data, 8);
                        status = nfsd4_decode_fattr(argp, open->op_bmval,
                                &open->op_iattr, &open->op_acl);
                        if (status)
                                goto out;
                        break;
                default:
                        goto xdr_error;
                }
                break;
        default:
                goto xdr_error;
        }

        /* open_claim */
        READ_BUF(4);
        READ32(open->op_claim_type);
        switch (open->op_claim_type) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                READ_BUF(4);
                READ32(open->op_fname.len);
                READ_BUF(open->op_fname.len);
                SAVEMEM(open->op_fname.data, open->op_fname.len);
                if ((status = check_filename(open->op_fname.data, open->op_fname.len, nfserr_inval)))
                        return status;
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
                READ_BUF(4);
                READ32(open->op_delegate_type);
                break;
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
                status = nfsd4_decode_stateid(argp, &open->op_delegate_stateid);
                if (status)
                        return status;
                READ_BUF(4);
                READ32(open->op_fname.len);
                READ_BUF(open->op_fname.len);
                SAVEMEM(open->op_fname.data, open->op_fname.len);
                if ((status = check_filename(open->op_fname.data, open->op_fname.len, nfserr_inval)))
                        return status;
                break;
        default:
                goto xdr_error;
        }

        DECODE_TAIL;
}

static __be32
nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_open_confirm *open_conf)
{
        DECODE_HEAD;
                    
        open_conf->oc_stateowner = NULL;
        status = nfsd4_decode_stateid(argp, &open_conf->oc_req_stateid);
        if (status)
                return status;
        READ_BUF(4);
        READ32(open_conf->oc_seqid);
                                                        
        DECODE_TAIL;
}

static __be32
nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
{
        DECODE_HEAD;
                    
        open_down->od_stateowner = NULL;
        status = nfsd4_decode_stateid(argp, &open_down->od_stateid);
        if (status)
                return status;
        READ_BUF(12);
        READ32(open_down->od_seqid);
        READ32(open_down->od_share_access);
        READ32(open_down->od_share_deny);
                                                        
        DECODE_TAIL;
}

static __be32
nfsd4_decode_putfh(struct nfsd4_compoundargs *argp, struct nfsd4_putfh *putfh)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(putfh->pf_fhlen);
        if (putfh->pf_fhlen > NFS4_FHSIZE)
                goto xdr_error;
        READ_BUF(putfh->pf_fhlen);
        SAVEMEM(putfh->pf_fhval, putfh->pf_fhlen);

        DECODE_TAIL;
}

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

        status = nfsd4_decode_stateid(argp, &read->rd_stateid);
        if (status)
                return status;
        READ_BUF(12);
        READ64(read->rd_offset);
        READ32(read->rd_length);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_readdir(struct nfsd4_compoundargs *argp, struct nfsd4_readdir *readdir)
{
        DECODE_HEAD;

        READ_BUF(24);
        READ64(readdir->rd_cookie);
        COPYMEM(readdir->rd_verf.data, sizeof(readdir->rd_verf.data));
        READ32(readdir->rd_dircount);    /* just in case you needed a useless field... */
        READ32(readdir->rd_maxcount);
        if ((status = nfsd4_decode_bitmap(argp, readdir->rd_bmval)))
                goto out;

        DECODE_TAIL;
}

static __be32
nfsd4_decode_remove(struct nfsd4_compoundargs *argp, struct nfsd4_remove *remove)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(remove->rm_namelen);
        READ_BUF(remove->rm_namelen);
        SAVEMEM(remove->rm_name, remove->rm_namelen);
        if ((status = check_filename(remove->rm_name, remove->rm_namelen, nfserr_noent)))
                return status;

        DECODE_TAIL;
}

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

        READ_BUF(4);
        READ32(rename->rn_snamelen);
        READ_BUF(rename->rn_snamelen + 4);
        SAVEMEM(rename->rn_sname, rename->rn_snamelen);
        READ32(rename->rn_tnamelen);
        READ_BUF(rename->rn_tnamelen);
        SAVEMEM(rename->rn_tname, rename->rn_tnamelen);
        if ((status = check_filename(rename->rn_sname, rename->rn_snamelen, nfserr_noent)))
                return status;
        if ((status = check_filename(rename->rn_tname, rename->rn_tnamelen, nfserr_inval)))
                return status;

        DECODE_TAIL;
}

static __be32
nfsd4_decode_renew(struct nfsd4_compoundargs *argp, clientid_t *clientid)
{
        DECODE_HEAD;

        READ_BUF(sizeof(clientid_t));
        COPYMEM(clientid, sizeof(clientid_t));

        DECODE_TAIL;
}

static __be32
nfsd4_decode_secinfo(struct nfsd4_compoundargs *argp,
                     struct nfsd4_secinfo *secinfo)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(secinfo->si_namelen);
        READ_BUF(secinfo->si_namelen);
        SAVEMEM(secinfo->si_name, secinfo->si_namelen);
        status = check_filename(secinfo->si_name, secinfo->si_namelen,
                                                                nfserr_noent);
        if (status)
                return status;
        DECODE_TAIL;
}

static __be32
nfsd4_decode_secinfo_no_name(struct nfsd4_compoundargs *argp,
                     struct nfsd4_secinfo_no_name *sin)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(sin->sin_style);
        DECODE_TAIL;
}

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

        status = nfsd4_decode_stateid(argp, &setattr->sa_stateid);
        if (status)
                return status;
        return nfsd4_decode_fattr(argp, setattr->sa_bmval, &setattr->sa_iattr,
                                  &setattr->sa_acl);
}

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

        READ_BUF(12);
        COPYMEM(setclientid->se_verf.data, 8);
        READ32(setclientid->se_namelen);

        READ_BUF(setclientid->se_namelen + 8);
        SAVEMEM(setclientid->se_name, setclientid->se_namelen);
        READ32(setclientid->se_callback_prog);
        READ32(setclientid->se_callback_netid_len);

        READ_BUF(setclientid->se_callback_netid_len + 4);
        SAVEMEM(setclientid->se_callback_netid_val, setclientid->se_callback_netid_len);
        READ32(setclientid->se_callback_addr_len);

        READ_BUF(setclientid->se_callback_addr_len + 4);
        SAVEMEM(setclientid->se_callback_addr_val, setclientid->se_callback_addr_len);
        READ32(setclientid->se_callback_ident);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_setclientid_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_setclientid_confirm *scd_c)
{
        DECODE_HEAD;

        READ_BUF(8 + sizeof(nfs4_verifier));
        COPYMEM(&scd_c->sc_clientid, 8);
        COPYMEM(&scd_c->sc_confirm, sizeof(nfs4_verifier));

        DECODE_TAIL;
}

/* Also used for NVERIFY */
static __be32
nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify)
{
#if 0
        struct nfsd4_compoundargs save = {
                .p = argp->p,
                .end = argp->end,
                .rqstp = argp->rqstp,
        };
        u32             ve_bmval[2];
        struct iattr    ve_iattr;           /* request */
        struct nfs4_acl *ve_acl;            /* request */
#endif
        DECODE_HEAD;

        if ((status = nfsd4_decode_bitmap(argp, verify->ve_bmval)))
                goto out;

        /* For convenience's sake, we compare raw xdr'd attributes in
         * nfsd4_proc_verify; however we still decode here just to return
         * correct error in case of bad xdr. */
#if 0
        status = nfsd4_decode_fattr(ve_bmval, &ve_iattr, &ve_acl);
        if (status == nfserr_inval) {
                status = nfserrno(status);
                goto out;
        }
#endif
        READ_BUF(4);
        READ32(verify->ve_attrlen);
        READ_BUF(verify->ve_attrlen);
        SAVEMEM(verify->ve_attrval, verify->ve_attrlen);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
{
        int avail;
        int v;
        int len;
        DECODE_HEAD;

        status = nfsd4_decode_stateid(argp, &write->wr_stateid);
        if (status)
                return status;
        READ_BUF(16);
        READ64(write->wr_offset);
        READ32(write->wr_stable_how);
        if (write->wr_stable_how > 2)
                goto xdr_error;
        READ32(write->wr_buflen);

        /* Sorry .. no magic macros for this.. *
         * READ_BUF(write->wr_buflen);
         * SAVEMEM(write->wr_buf, write->wr_buflen);
         */
        avail = (char*)argp->end - (char*)argp->p;
        if (avail + argp->pagelen < write->wr_buflen) {
                dprintk("NFSD: xdr error (%s:%d)\n",
                                __FILE__, __LINE__);
                goto xdr_error;
        }
        argp->rqstp->rq_vec[0].iov_base = p;
        argp->rqstp->rq_vec[0].iov_len = avail;
        v = 0;
        len = write->wr_buflen;
        while (len > argp->rqstp->rq_vec[v].iov_len) {
                len -= argp->rqstp->rq_vec[v].iov_len;
                v++;
                argp->rqstp->rq_vec[v].iov_base = page_address(argp->pagelist[0]);
                argp->pagelist++;
                if (argp->pagelen >= PAGE_SIZE) {
                        argp->rqstp->rq_vec[v].iov_len = PAGE_SIZE;
                        argp->pagelen -= PAGE_SIZE;
                } else {
                        argp->rqstp->rq_vec[v].iov_len = argp->pagelen;
                        argp->pagelen -= len;
                }

        }
        argp->end = (__be32*) (argp->rqstp->rq_vec[v].iov_base + argp->rqstp->rq_vec[v].iov_len);
        argp->p = (__be32*)  (argp->rqstp->rq_vec[v].iov_base + (XDR_QUADLEN(len) << 2));
        argp->rqstp->rq_vec[v].iov_len = len;
        write->wr_vlen = v+1;

        DECODE_TAIL;
}

static __be32
nfsd4_decode_release_lockowner(struct nfsd4_compoundargs *argp, struct nfsd4_release_lockowner *rlockowner)
{
        DECODE_HEAD;

        READ_BUF(12);
        COPYMEM(&rlockowner->rl_clientid, sizeof(clientid_t));
        READ32(rlockowner->rl_owner.len);
        READ_BUF(rlockowner->rl_owner.len);
        READMEM(rlockowner->rl_owner.data, rlockowner->rl_owner.len);

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

static __be32
nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
                         struct nfsd4_exchange_id *exid)
{
        int dummy, tmp;
        DECODE_HEAD;

        READ_BUF(NFS4_VERIFIER_SIZE);
        COPYMEM(exid->verifier.data, NFS4_VERIFIER_SIZE);

        READ_BUF(4);
        READ32(exid->clname.len);

        READ_BUF(exid->clname.len);
        SAVEMEM(exid->clname.data, exid->clname.len);

        READ_BUF(4);
        READ32(exid->flags);

        /* Ignore state_protect4_a */
        READ_BUF(4);
        READ32(exid->spa_how);
        switch (exid->spa_how) {
        case SP4_NONE:
                break;
        case SP4_MACH_CRED:
                /* spo_must_enforce */
                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy * 4);
                p += dummy;

                /* spo_must_allow */
                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy * 4);
                p += dummy;
                break;
        case SP4_SSV:
                /* ssp_ops */
                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy * 4);
                p += dummy;

                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy * 4);
                p += dummy;

                /* ssp_hash_algs<> */
                READ_BUF(4);
                READ32(tmp);
                while (tmp--) {
                        READ_BUF(4);
                        READ32(dummy);
                        READ_BUF(dummy);
                        p += XDR_QUADLEN(dummy);
                }

                /* ssp_encr_algs<> */
                READ_BUF(4);
                READ32(tmp);
                while (tmp--) {
                        READ_BUF(4);
                        READ32(dummy);
                        READ_BUF(dummy);
                        p += XDR_QUADLEN(dummy);
                }

                /* ssp_window and ssp_num_gss_handles */
                READ_BUF(8);
                READ32(dummy);
                READ32(dummy);
                break;
        default:
                goto xdr_error;
        }

        /* Ignore Implementation ID */
        READ_BUF(4);    /* nfs_impl_id4 array length */
        READ32(dummy);

        if (dummy > 1)
                goto xdr_error;

        if (dummy == 1) {
                /* nii_domain */
                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy);
                p += XDR_QUADLEN(dummy);

                /* nii_name */
                READ_BUF(4);
                READ32(dummy);
                READ_BUF(dummy);
                p += XDR_QUADLEN(dummy);

                /* nii_date */
                READ_BUF(12);
                p += 3;
        }
        DECODE_TAIL;
}

static __be32
nfsd4_decode_create_session(struct nfsd4_compoundargs *argp,
                            struct nfsd4_create_session *sess)
{
        DECODE_HEAD;

        u32 dummy;
        char *machine_name;
        int i;
        int nr_secflavs;

        READ_BUF(16);
        COPYMEM(&sess->clientid, 8);
        READ32(sess->seqid);
        READ32(sess->flags);

        /* Fore channel attrs */
        READ_BUF(28);
        READ32(dummy); /* headerpadsz is always 0 */
        READ32(sess->fore_channel.maxreq_sz);
        READ32(sess->fore_channel.maxresp_sz);
        READ32(sess->fore_channel.maxresp_cached);
        READ32(sess->fore_channel.maxops);
        READ32(sess->fore_channel.maxreqs);
        READ32(sess->fore_channel.nr_rdma_attrs);
        if (sess->fore_channel.nr_rdma_attrs == 1) {
                READ_BUF(4);
                READ32(sess->fore_channel.rdma_attrs);
        } else if (sess->fore_channel.nr_rdma_attrs > 1) {
                dprintk("Too many fore channel attr bitmaps!\n");
                goto xdr_error;
        }

        /* Back channel attrs */
        READ_BUF(28);
        READ32(dummy); /* headerpadsz is always 0 */
        READ32(sess->back_channel.maxreq_sz);
        READ32(sess->back_channel.maxresp_sz);
        READ32(sess->back_channel.maxresp_cached);
        READ32(sess->back_channel.maxops);
        READ32(sess->back_channel.maxreqs);
        READ32(sess->back_channel.nr_rdma_attrs);
        if (sess->back_channel.nr_rdma_attrs == 1) {
                READ_BUF(4);
                READ32(sess->back_channel.rdma_attrs);
        } else if (sess->back_channel.nr_rdma_attrs > 1) {
                dprintk("Too many back channel attr bitmaps!\n");
                goto xdr_error;
        }

        READ_BUF(8);
        READ32(sess->callback_prog);

        /* callback_sec_params4 */
        READ32(nr_secflavs);
        for (i = 0; i < nr_secflavs; ++i) {
                READ_BUF(4);
                READ32(dummy);
                switch (dummy) {
                case RPC_AUTH_NULL:
                        /* Nothing to read */
                        break;
                case RPC_AUTH_UNIX:
                        READ_BUF(8);
                        /* stamp */
                        READ32(dummy);

                        /* machine name */
                        READ32(dummy);
                        READ_BUF(dummy);
                        SAVEMEM(machine_name, dummy);

                        /* uid, gid */
                        READ_BUF(8);
                        READ32(sess->uid);
                        READ32(sess->gid);

                        /* more gids */
                        READ_BUF(4);
                        READ32(dummy);
                        READ_BUF(dummy * 4);
                        break;
                case RPC_AUTH_GSS:
                        dprintk("RPC_AUTH_GSS callback secflavor "
                                "not supported!\n");
                        READ_BUF(8);
                        /* gcbp_service */
                        READ32(dummy);
                        /* gcbp_handle_from_server */
                        READ32(dummy);
                        READ_BUF(dummy);
                        p += XDR_QUADLEN(dummy);
                        /* gcbp_handle_from_client */
                        READ_BUF(4);
                        READ32(dummy);
                        READ_BUF(dummy);
                        break;
                default:
                        dprintk("Illegal callback secflavor\n");
                        return nfserr_inval;
                }
        }
        DECODE_TAIL;
}

static __be32
nfsd4_decode_destroy_session(struct nfsd4_compoundargs *argp,
                             struct nfsd4_destroy_session *destroy_session)
{
        DECODE_HEAD;
        READ_BUF(NFS4_MAX_SESSIONID_LEN);
        COPYMEM(destroy_session->sessionid.data, NFS4_MAX_SESSIONID_LEN);

        DECODE_TAIL;
}

static __be32
nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
                      struct nfsd4_sequence *seq)
{
        DECODE_HEAD;

        READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
        COPYMEM(seq->sessionid.data, NFS4_MAX_SESSIONID_LEN);
        READ32(seq->seqid);
        READ32(seq->slotid);
        READ32(seq->maxslots);
        READ32(seq->cachethis);

        DECODE_TAIL;
}

static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp, struct nfsd4_reclaim_complete *rc)
{
        DECODE_HEAD;

        READ_BUF(4);
        READ32(rc->rca_one_fs);

        DECODE_TAIL;
}

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 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_noop,
        [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,
};

static nfsd4_dec nfsd41_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_notsupp,
        [OP_OPEN_DOWNGRADE]     = (nfsd4_dec)nfsd4_decode_open_downgrade,
        [OP_PUTFH]              = (nfsd4_dec)nfsd4_decode_putfh,
        [OP_PUTPUBFH]           = (nfsd4_dec)nfsd4_decode_notsupp,
        [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_notsupp,
        [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_notsupp,
        [OP_SETCLIENTID_CONFIRM]= (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_VERIFY]             = (nfsd4_dec)nfsd4_decode_verify,
        [OP_WRITE]              = (nfsd4_dec)nfsd4_decode_write,
        [OP_RELEASE_LOCKOWNER]  = (nfsd4_dec)nfsd4_decode_notsupp,

        /* new operations for NFSv4.1 */
        [OP_BACKCHANNEL_CTL]    = (nfsd4_dec)nfsd4_decode_notsupp,
        [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_notsupp,
        [OP_GET_DIR_DELEGATION] = (nfsd4_dec)nfsd4_decode_notsupp,
        [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,
        [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_notsupp,
        [OP_WANT_DELEGATION]    = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_DESTROY_CLIENTID]   = (nfsd4_dec)nfsd4_decode_notsupp,
        [OP_RECLAIM_COMPLETE]   = (nfsd4_dec)nfsd4_decode_reclaim_complete,
};

struct nfsd4_minorversion_ops {
        nfsd4_dec *decoders;
        int nops;
};

static struct nfsd4_minorversion_ops nfsd4_minorversion[] = {
        [0] = { nfsd4_dec_ops, ARRAY_SIZE(nfsd4_dec_ops) },
        [1] = { nfsd41_dec_ops, ARRAY_SIZE(nfsd41_dec_ops) },
};

static __be32
nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
{
        DECODE_HEAD;
        struct nfsd4_op *op;
        struct nfsd4_minorversion_ops *ops;
        int i;

        /*
         * XXX: According to spec, we should check the tag
         * for UTF-8 compliance.  I'm postponing this for
         * now because it seems that some clients do use
         * binary tags.
         */
        READ_BUF(4);
        READ32(argp->taglen);
        READ_BUF(argp->taglen + 8);
        SAVEMEM(argp->tag, argp->taglen);
        READ32(argp->minorversion);
        READ32(argp->opcnt);

        if (argp->taglen > NFSD4_MAX_TAGLEN)
                goto xdr_error;
        if (argp->opcnt > 100)
                goto xdr_error;

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

        if (argp->minorversion >= ARRAY_SIZE(nfsd4_minorversion))
                argp->opcnt = 0;

        ops = &nfsd4_minorversion[argp->minorversion];
        for (i = 0; i < argp->opcnt; i++) {
                op = &argp->ops[i];
                op->replay = NULL;

                /*
                 * We can't use READ_BUF() here because we need to handle
                 * a missing opcode as an OP_WRITE + 1. So we need to check
                 * to see if we're truly at the end of our buffer or if there
                 * is another page we need to flip to.
                 */

                if (argp->p == argp->end) {
                        if (argp->pagelen < 4) {
                                /* There isn't an opcode still on the wire */
                                op->opnum = OP_WRITE + 1;
                                op->status = nfserr_bad_xdr;
                                argp->opcnt = i+1;
                                break;
                        }

                        /*
                         * False alarm. We just hit a page boundary, but there
                         * is still data available.  Move pointer across page
                         * boundary.  *snip from READ_BUF*
                         */
                        argp->p = page_address(argp->pagelist[0]);
                        argp->pagelist++;
                        if (argp->pagelen < PAGE_SIZE) {
                                argp->end = argp->p + (argp->pagelen>>2);
                                argp->pagelen = 0;
                        } else {
                                argp->end = argp->p + (PAGE_SIZE>>2);
                                argp->pagelen -= PAGE_SIZE;
                        }
                }
                op->opnum = ntohl(*argp->p++);

                if (op->opnum >= FIRST_NFS4_OP && op->opnum <= LAST_NFS4_OP)
                        op->status = ops->decoders[op->opnum](argp, &op->u);
                else {
                        op->opnum = OP_ILLEGAL;
                        op->status = nfserr_op_illegal;
                }

                if (op->status) {
                        argp->opcnt = i+1;
                        break;
                }
        }

        DECODE_TAIL;
}

#define WRITE32(n)               *p++ = htonl(n)
#define WRITE64(n)               do {                           \
        *p++ = htonl((u32)((n) >> 32));                         \
        *p++ = htonl((u32)(n));                                 \
} while (0)
#define WRITEMEM(ptr,nbytes)     do { if (nbytes > 0) {         \
        *(p + XDR_QUADLEN(nbytes) -1) = 0;                      \
        memcpy(p, ptr, nbytes);                                 \
        p += XDR_QUADLEN(nbytes);                               \
}} while (0)

static void write32(__be32 **p, u32 n)
{
        *(*p)++ = n;
}

static void write64(__be32 **p, u64 n)
{
        write32(p, (u32)(n >> 32));
        write32(p, (u32)n);
}

static void write_change(__be32 **p, struct kstat *stat, struct inode *inode)
{
        if (IS_I_VERSION(inode)) {
                write64(p, inode->i_version);
        } else {
                write32(p, stat->ctime.tv_sec);
                write32(p, stat->ctime.tv_nsec);
        }
}

static void write_cinfo(__be32 **p, struct nfsd4_change_info *c)
{
        write32(p, c->atomic);
        if (c->change_supported) {
                write64(p, c->before_change);
                write64(p, c->after_change);
        } else {
                write32(p, c->before_ctime_sec);
                write32(p, c->before_ctime_nsec);
                write32(p, c->after_ctime_sec);
                write32(p, c->after_ctime_nsec);
        }
}

#define RESERVE_SPACE(nbytes)   do {                            \
        p = resp->p;                                            \
        BUG_ON(p + XDR_QUADLEN(nbytes) > resp->end);            \
} while (0)
#define ADJUST_ARGS()           resp->p = p

/*
 * Header routine to setup seqid operation replay cache
 */
#define ENCODE_SEQID_OP_HEAD                                    \
        __be32 *save;                                           \
                                                                \
        save = resp->p;

/*
 * Routine for encoding the result of a "seqid-mutating" NFSv4 operation.  This
 * is where sequence id's are incremented, and the replay cache is filled.
 * Note that we increment sequence id's here, at the last moment, so we're sure
 * we know whether the error to be returned is a sequence id mutating error.
 */

#define ENCODE_SEQID_OP_TAIL(stateowner) do {                   \
        if (seqid_mutating_err(nfserr) && stateowner) {         \
                stateowner->so_seqid++;                         \
                stateowner->so_replay.rp_status = nfserr;       \
                stateowner->so_replay.rp_buflen =               \
                          (((char *)(resp)->p - (char *)save)); \
                memcpy(stateowner->so_replay.rp_buf, save,      \
                        stateowner->so_replay.rp_buflen);       \
        } } while (0);

/* Encode as an array of strings the string given with components
 * separated @sep.
 */
static __be32 nfsd4_encode_components(char sep, char *components,
                                   __be32 **pp, int *buflen)
{
        __be32 *p = *pp;
        __be32 *countp = p;
        int strlen, count=0;
        char *str, *end;

        dprintk("nfsd4_encode_components(%s)\n", components);
        if ((*buflen -= 4) < 0)
                return nfserr_resource;
        WRITE32(0); /* We will fill this in with @count later */
        end = str = components;
        while (*end) {
                for (; *end && (*end != sep); end++)
                        ; /* Point to end of component */
                strlen = end - str;
                if (strlen) {
                        if ((*buflen -= ((XDR_QUADLEN(strlen) << 2) + 4)) < 0)
                                return nfserr_resource;
                        WRITE32(strlen);
                        WRITEMEM(str, strlen);
                        count++;
                }
                else
                        end++;
                str = end;
        }
        *pp = p;
        p = countp;
        WRITE32(count);
        return 0;
}

/*
 * encode a location element of a fs_locations structure
 */
static __be32 nfsd4_encode_fs_location4(struct nfsd4_fs_location *location,
                                    __be32 **pp, int *buflen)
{
        __be32 status;
        __be32 *p = *pp;

        status = nfsd4_encode_components(':', location->hosts, &p, buflen);
        if (status)
                return status;
        status = nfsd4_encode_components('/', location->path, &p, buflen);
        if (status)
                return status;
        *pp = p;
        return 0;
}

/*
 * Return the path to an export point in the pseudo filesystem namespace
 * Returned string is safe to use as long as the caller holds a reference
 * to @exp.
 */
static char *nfsd4_path(struct svc_rqst *rqstp, struct svc_export *exp, __be32 *stat)
{
        struct svc_fh tmp_fh;
        char *path = NULL, *rootpath;
        size_t rootlen;

        fh_init(&tmp_fh, NFS4_FHSIZE);
        *stat = exp_pseudoroot(rqstp, &tmp_fh);
        if (*stat)
                return NULL;
        rootpath = tmp_fh.fh_export->ex_pathname;

        path = exp->ex_pathname;

        rootlen = strlen(rootpath);
        if (strncmp(path, rootpath, rootlen)) {
                dprintk("nfsd: fs_locations failed;"
                        "%s is not contained in %s\n", path, rootpath);
                *stat = nfserr_notsupp;
                path = NULL;
                goto out;
        }
        path += rootlen;
out:
        fh_put(&tmp_fh);
        return path;
}

/*
 *  encode a fs_locations structure
 */
static __be32 nfsd4_encode_fs_locations(struct svc_rqst *rqstp,
                                     struct svc_export *exp,
                                     __be32 **pp, int *buflen)
{
        __be32 status;
        int i;
        __be32 *p = *pp;
        struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;
        char *root = nfsd4_path(rqstp, exp, &status);

        if (status)
                return status;
        status = nfsd4_encode_components('/', root, &p, buflen);
        if (status)
                return status;
        if ((*buflen -= 4) < 0)
                return nfserr_resource;
        WRITE32(fslocs->locations_count);
        for (i=0; i<fslocs->locations_count; i++) {
                status = nfsd4_encode_fs_location4(&fslocs->locations[i],
                                                   &p, buflen);
                if (status)
                        return status;
        }
        *pp = p;
        return 0;
}

static u32 nfs4_ftypes[16] = {
        NF4BAD,  NF4FIFO, NF4CHR, NF4BAD,
        NF4DIR,  NF4BAD,  NF4BLK, NF4BAD,
        NF4REG,  NF4BAD,  NF4LNK, NF4BAD,
        NF4SOCK, NF4BAD,  NF4LNK, NF4BAD,
};

static __be32
nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
                        __be32 **p, int *buflen)
{
        int status;

        if (*buflen < (XDR_QUADLEN(IDMAP_NAMESZ) << 2) + 4)
                return nfserr_resource;
        if (whotype != NFS4_ACL_WHO_NAMED)
                status = nfs4_acl_write_who(whotype, (u8 *)(*p + 1));
        else if (group)
                status = nfsd_map_gid_to_name(rqstp, id, (u8 *)(*p + 1));
        else
                status = nfsd_map_uid_to_name(rqstp, id, (u8 *)(*p + 1));
        if (status < 0)
                return nfserrno(status);
        *p = xdr_encode_opaque(*p, NULL, status);
        *buflen -= (XDR_QUADLEN(status) << 2) + 4;
        BUG_ON(*buflen < 0);
        return 0;
}

static inline __be32
nfsd4_encode_user(struct svc_rqst *rqstp, uid_t uid, __be32 **p, int *buflen)
{
        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, uid, 0, p, buflen);
}

static inline __be32
nfsd4_encode_group(struct svc_rqst *rqstp, uid_t gid, __be32 **p, int *buflen)
{
        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, gid, 1, p, buflen);
}

static inline __be32
nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
                __be32 **p, int *buflen)
{
        return nfsd4_encode_name(rqstp, whotype, id, group, p, buflen);
}

#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

static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, 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;
        return 0;
}

/*
 * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
 * ourselves.
 *
 * @countp is the buffer size in _words_; upon successful return this becomes
 * replaced with the number of words written.
 */
__be32
nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
                struct dentry *dentry, __be32 *buffer, int *countp, 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;
        struct kstatfs statfs;
        int buflen = *countp << 2;
        __be32 *attrlenp;
        u32 dummy;
        u64 dummy64;
        u32 rdattr_err = 0;
        __be32 *p = buffer;
        __be32 status;
        int err;
        int aclsupport = 0;
        struct nfs4_acl *acl = NULL;
        struct nfsd4_compoundres *resp = rqstp->rq_resp;
        u32 minorversion = resp->cstate.minorversion;
        struct path path = {
                .mnt    = exp->ex_path.mnt,
                .dentry = dentry,
        };

        BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
        BUG_ON(bmval0 & ~nfsd_suppattrs0(minorversion));
        BUG_ON(bmval1 & ~nfsd_suppattrs1(minorversion));
        BUG_ON(bmval2 & ~nfsd_suppattrs2(minorversion));

        if (exp->ex_fslocs.migrated) {
                BUG_ON(bmval[2]);
                status = fattr_handle_absent_fs(&bmval0, &bmval1, &rdattr_err);
                if (status)
                        goto out;
        }

        err = vfs_getattr(exp->ex_path.mnt, dentry, &stat);
        if (err)
                goto out_nfserr;
        if ((bmval0 & (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) {
                fh_init(&tempfh, NFS4_FHSIZE);
                status = fh_compose(&tempfh, exp, dentry, NULL);
                if (status)
                        goto out;
                fhp = &tempfh;
        }
        if (bmval0 & (FATTR4_WORD0_ACL | FATTR4_WORD0_ACLSUPPORT
                        | FATTR4_WORD0_SUPPORTED_ATTRS)) {
                err = nfsd4_get_nfs4_acl(rqstp, dentry, &acl);
                aclsupport = (err == 0);
                if (bmval0 & FATTR4_WORD0_ACL) {
                        if (err == -EOPNOTSUPP)
                                bmval0 &= ~FATTR4_WORD0_ACL;
                        else if (err == -EINVAL) {
                                status = nfserr_attrnotsupp;
                                goto out;
                        } else if (err != 0)
                                goto out_nfserr;
                }
        }

        if (bmval2) {
                if ((buflen -= 16) < 0)
                        goto out_resource;
                WRITE32(3);
                WRITE32(bmval0);
                WRITE32(bmval1);
                WRITE32(bmval2);
        } else if (bmval1) {
                if ((buflen -= 12) < 0)
                        goto out_resource;
                WRITE32(2);
                WRITE32(bmval0);
                WRITE32(bmval1);
        } else {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE32(1);
                WRITE32(bmval0);
        }
        attrlenp = p++;                /* to be backfilled later */

        if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
                u32 word0 = nfsd_suppattrs0(minorversion);
                u32 word1 = nfsd_suppattrs1(minorversion);
                u32 word2 = nfsd_suppattrs2(minorversion);

                if (!aclsupport)
                        word0 &= ~FATTR4_WORD0_ACL;
                if (!word2) {
                        if ((buflen -= 12) < 0)
                                goto out_resource;
                        WRITE32(2);
                        WRITE32(word0);
                        WRITE32(word1);
                } else {
                        if ((buflen -= 16) < 0)
                                goto out_resource;
                        WRITE32(3);
                        WRITE32(word0);
                        WRITE32(word1);
                        WRITE32(word2);
                }
        }
        if (bmval0 & FATTR4_WORD0_TYPE) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                dummy = nfs4_ftypes[(stat.mode & S_IFMT) >> 12];
                if (dummy == NF4BAD)
                        goto out_serverfault;
                WRITE32(dummy);
        }
        if (bmval0 & FATTR4_WORD0_FH_EXPIRE_TYPE) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
                        WRITE32(NFS4_FH_PERSISTENT);
                else
                        WRITE32(NFS4_FH_PERSISTENT|NFS4_FH_VOL_RENAME);
        }
        if (bmval0 & FATTR4_WORD0_CHANGE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                write_change(&p, &stat, dentry->d_inode);
        }
        if (bmval0 & FATTR4_WORD0_SIZE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64(stat.size);
        }
        if (bmval0 & FATTR4_WORD0_LINK_SUPPORT) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_SYMLINK_SUPPORT) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_NAMED_ATTR) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(0);
        }
        if (bmval0 & FATTR4_WORD0_FSID) {
                if ((buflen -= 16) < 0)
                        goto out_resource;
                if (exp->ex_fslocs.migrated) {
                        WRITE64(NFS4_REFERRAL_FSID_MAJOR);
                        WRITE64(NFS4_REFERRAL_FSID_MINOR);
                } else switch(fsid_source(fhp)) {
                case FSIDSOURCE_FSID:
                        WRITE64((u64)exp->ex_fsid);
                        WRITE64((u64)0);
                        break;
                case FSIDSOURCE_DEV:
                        WRITE32(0);
                        WRITE32(MAJOR(stat.dev));
                        WRITE32(0);
                        WRITE32(MINOR(stat.dev));
                        break;
                case FSIDSOURCE_UUID:
                        WRITEMEM(exp->ex_uuid, 16);
                        break;
                }
        }
        if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(0);
        }
        if (bmval0 & FATTR4_WORD0_LEASE_TIME) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(nfsd4_lease);
        }
        if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(rdattr_err);
        }
        if (bmval0 & FATTR4_WORD0_ACL) {
                struct nfs4_ace *ace;

                if (acl == NULL) {
                        if ((buflen -= 4) < 0)
                                goto out_resource;

                        WRITE32(0);
                        goto out_acl;
                }
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(acl->naces);

                for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
                        if ((buflen -= 4*3) < 0)
                                goto out_resource;
                        WRITE32(ace->type);
                        WRITE32(ace->flag);
                        WRITE32(ace->access_mask & NFS4_ACE_MASK_ALL);
                        status = nfsd4_encode_aclname(rqstp, ace->whotype,
                                ace->who, ace->flag & NFS4_ACE_IDENTIFIER_GROUP,
                                &p, &buflen);
                        if (status == nfserr_resource)
                                goto out_resource;
                        if (status)
                                goto out;
                }
        }
out_acl:
        if (bmval0 & FATTR4_WORD0_ACLSUPPORT) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(aclsupport ?
                        ACL4_SUPPORT_ALLOW_ACL|ACL4_SUPPORT_DENY_ACL : 0);
        }
        if (bmval0 & FATTR4_WORD0_CANSETTIME) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
                if ((buflen -= 4) < 0)
                        goto out_resource;

                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_CHOWN_RESTRICTED) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_FILEHANDLE) {
                buflen -= (XDR_QUADLEN(fhp->fh_handle.fh_size) << 2) + 4;
                if (buflen < 0)
                        goto out_resource;
                WRITE32(fhp->fh_handle.fh_size);
                WRITEMEM(&fhp->fh_handle.fh_base, fhp->fh_handle.fh_size);
        }
        if (bmval0 & FATTR4_WORD0_FILEID) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64(stat.ino);
        }
        if (bmval0 & FATTR4_WORD0_FILES_AVAIL) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64((u64) statfs.f_ffree);
        }
        if (bmval0 & FATTR4_WORD0_FILES_FREE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64((u64) statfs.f_ffree);
        }
        if (bmval0 & FATTR4_WORD0_FILES_TOTAL) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64((u64) statfs.f_files);
        }
        if (bmval0 & FATTR4_WORD0_FS_LOCATIONS) {
                status = nfsd4_encode_fs_locations(rqstp, exp, &p, &buflen);
                if (status == nfserr_resource)
                        goto out_resource;
                if (status)
                        goto out;
        }
        if (bmval0 & FATTR4_WORD0_HOMOGENEOUS) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval0 & FATTR4_WORD0_MAXFILESIZE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64(~(u64)0);
        }
        if (bmval0 & FATTR4_WORD0_MAXLINK) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(255);
        }
        if (bmval0 & FATTR4_WORD0_MAXNAME) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(statfs.f_namelen);
        }
        if (bmval0 & FATTR4_WORD0_MAXREAD) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64((u64) svc_max_payload(rqstp));
        }
        if (bmval0 & FATTR4_WORD0_MAXWRITE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE64((u64) svc_max_payload(rqstp));
        }
        if (bmval1 & FATTR4_WORD1_MODE) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(stat.mode & S_IALLUGO);
        }
        if (bmval1 & FATTR4_WORD1_NO_TRUNC) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(1);
        }
        if (bmval1 & FATTR4_WORD1_NUMLINKS) {
                if ((buflen -= 4) < 0)
                        goto out_resource;
                WRITE32(stat.nlink);
        }
        if (bmval1 & FATTR4_WORD1_OWNER) {
                status = nfsd4_encode_user(rqstp, stat.uid, &p, &buflen);
                if (status == nfserr_resource)
                        goto out_resource;
                if (status)
                        goto out;
        }
        if (bmval1 & FATTR4_WORD1_OWNER_GROUP) {
                status = nfsd4_encode_group(rqstp, stat.gid, &p, &buflen);
                if (status == nfserr_resource)
                        goto out_resource;
                if (status)
                        goto out;
        }
        if (bmval1 & FATTR4_WORD1_RAWDEV) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                WRITE32((u32) MAJOR(stat.rdev));
                WRITE32((u32) MINOR(stat.rdev));
        }
        if (bmval1 & FATTR4_WORD1_SPACE_AVAIL) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                dummy64 = (u64)statfs.f_bavail * (u64)statfs.f_bsize;
                WRITE64(dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_FREE) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                dummy64 = (u64)statfs.f_bfree * (u64)statfs.f_bsize;
                WRITE64(dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_TOTAL) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                dummy64 = (u64)statfs.f_blocks * (u64)statfs.f_bsize;
                WRITE64(dummy64);
        }
        if (bmval1 & FATTR4_WORD1_SPACE_USED) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                dummy64 = (u64)stat.blocks << 9;
                WRITE64(dummy64);
        }
        if (bmval1 & FATTR4_WORD1_TIME_ACCESS) {
                if ((buflen -= 12) < 0)
                        goto out_resource;
                WRITE32(0);
                WRITE32(stat.atime.tv_sec);
                WRITE32(stat.atime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
                if ((buflen -= 12) < 0)
                        goto out_resource;
                WRITE32(0);
                WRITE32(1);
                WRITE32(0);
        }
        if (bmval1 & FATTR4_WORD1_TIME_METADATA) {
                if ((buflen -= 12) < 0)
                        goto out_resource;
                WRITE32(0);
                WRITE32(stat.ctime.tv_sec);
                WRITE32(stat.ctime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_TIME_MODIFY) {
                if ((buflen -= 12) < 0)
                        goto out_resource;
                WRITE32(0);
                WRITE32(stat.mtime.tv_sec);
                WRITE32(stat.mtime.tv_nsec);
        }
        if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
                if ((buflen -= 8) < 0)
                        goto out_resource;
                /*
                 * Get parent's attributes if not ignoring crossmount
                 * and this is the root of a cross-mounted filesystem.
                 */
                if (ignore_crossmnt == 0 &&
                    dentry == exp->ex_path.mnt->mnt_root) {
                        struct path path = exp->ex_path;
                        path_get(&path);
                        while (follow_up(&path)) {
                                if (path.dentry != path.mnt->mnt_root)
                                        break;
                        }
                        err = vfs_getattr(path.mnt, path.dentry, &stat);
                        path_put(&path);
                        if (err)
                                goto out_nfserr;
                }
                WRITE64(stat.ino);
        }
        if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
                WRITE32(3);
                WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD0);
                WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD1);
                WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD2);
        }

        *attrlenp = htonl((char *)p - (char *)attrlenp - 4);
        *countp = p - buffer;
        status = nfs_ok;

out:
        kfree(acl);
        if (fhp == &tempfh)
                fh_put(&tempfh);
        return status;
out_nfserr:
        status = nfserrno(err);
        goto out;
out_resource:
        *countp = 0;
        status = nfserr_resource;
        goto out;
out_serverfault:
        status = nfserr_serverfault;
        goto out;
}

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

static __be32
nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
                const char *name, int namlen, __be32 *p, int *buflen)
{
        struct svc_export *exp = cd->rd_fhp->fh_export;
        struct dentry *dentry;
        __be32 nfserr;
        int ignore_crossmnt = 0;

        dentry = lookup_one_len(name, cd->rd_fhp->fh_dentry, namlen);
        if (IS_ERR(dentry))
                return nfserrno(PTR_ERR(dentry));
        if (!dentry->d_inode) {
                /*
                 * nfsd_buffered_readdir drops the i_mutex between
                 * readdir and calling this callback, leaving a window
                 * where this directory entry could have gone away.
                 */
                dput(dentry);
                return nfserr_noent;
        }

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

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

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

static __be32 *
nfsd4_encode_rdattr_error(__be32 *p, int buflen, __be32 nfserr)
{
        __be32 *attrlenp;

        if (buflen < 6)
                return NULL;
        *p++ = htonl(2);
        *p++ = htonl(FATTR4_WORD0_RDATTR_ERROR); /* bmval0 */
        *p++ = htonl(0);                         /* bmval1 */

        attrlenp = p++;
        *p++ = nfserr;       /* no htonl */
        *attrlenp = htonl((char *)p - (char *)attrlenp - 4);
        return p;
}

static int
nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
                    loff_t offset, u64 ino, unsigned int d_type)
{
        struct readdir_cd *ccd = ccdv;
        struct nfsd4_readdir *cd = container_of(ccd, struct nfsd4_readdir, common);
        int buflen;
        __be32 *p = cd->buffer;
        __be32 *cookiep;
        __be32 nfserr = nfserr_toosmall;

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

        if (cd->offset)
                xdr_encode_hyper(cd->offset, (u64) offset);

        buflen = cd->buflen - 4 - XDR_QUADLEN(namlen);
        if (buflen < 0)
                goto fail;

        *p++ = xdr_one;                             /* mark entry present */
        cookiep = p;
        p = xdr_encode_hyper(p, NFS_OFFSET_MAX);    /* offset of next entry */
        p = xdr_encode_array(p, name, namlen);      /* name length & name */

        nfserr = nfsd4_encode_dirent_fattr(cd, name, namlen, p, &buflen);
        switch (nfserr) {
        case nfs_ok:
                p += buflen;
                break;
        case nfserr_resource:
                nfserr = nfserr_toosmall;
                goto fail;
        case nfserr_noent:
                goto skip_entry;
        default:
                /*
                 * If the client requested the RDATTR_ERROR attribute,
                 * we stuff the error code into this attribute
                 * and continue.  If this attribute was not requested,
                 * then in accordance with the spec, we fail the
                 * entire READDIR operation(!)
                 */
                if (!(cd->rd_bmval[0] & FATTR4_WORD0_RDATTR_ERROR))
                        goto fail;
                p = nfsd4_encode_rdattr_error(p, buflen, nfserr);
                if (p == NULL) {
                        nfserr = nfserr_toosmall;
                        goto fail;
                }
        }
        cd->buflen -= (p - cd->buffer);
        cd->buffer = p;
        cd->offset = cookiep;
skip_entry:
        cd->common.err = nfs_ok;
        return 0;
fail:
        cd->common.err = nfserr;
        return -EINVAL;
}

static void
nfsd4_encode_stateid(struct nfsd4_compoundres *resp, stateid_t *sid)
{
        __be32 *p;

        RESERVE_SPACE(sizeof(stateid_t));
        WRITE32(sid->si_generation);
        WRITEMEM(&sid->si_opaque, sizeof(stateid_opaque_t));
        ADJUST_ARGS();
}

static __be32
nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(8);
                WRITE32(access->ac_supported);
                WRITE32(access->ac_resp_access);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(NFS4_MAX_SESSIONID_LEN + 8);
                WRITEMEM(bcts->sessionid.data, NFS4_MAX_SESSIONID_LEN);
                WRITE32(bcts->dir);
                /* XXX: ? */
                WRITE32(0);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32
nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_close *close)
{
        ENCODE_SEQID_OP_HEAD;

        if (!nfserr)
                nfsd4_encode_stateid(resp, &close->cl_stateid);

        ENCODE_SEQID_OP_TAIL(close->cl_stateowner);
        return nfserr;
}


static __be32
nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_commit *commit)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(8);
                WRITEMEM(commit->co_verf.data, 8);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32
nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_create *create)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(32);
                write_cinfo(&p, &create->cr_cinfo);
                WRITE32(2);
                WRITE32(create->cr_bmval[0]);
                WRITE32(create->cr_bmval[1]);
                ADJUST_ARGS();
        }
        return nfserr;
}

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

        if (nfserr)
                return nfserr;

        buflen = resp->end - resp->p - (COMPOUND_ERR_SLACK_SPACE >> 2);
        nfserr = nfsd4_encode_fattr(fhp, fhp->fh_export, fhp->fh_dentry,
                                    resp->p, &buflen, getattr->ga_bmval,
                                    resp->rqstp, 0);
        if (!nfserr)
                resp->p += buflen;
        return nfserr;
}

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

        if (!nfserr) {
                len = fhp->fh_handle.fh_size;
                RESERVE_SPACE(len + 4);
                WRITE32(len);
                WRITEMEM(&fhp->fh_handle.fh_base, len);
                ADJUST_ARGS();
        }
        return nfserr;
}

/*
* Including all fields other than the name, a LOCK4denied structure requires
*   8(clientid) + 4(namelen) + 8(offset) + 8(length) + 4(type) = 32 bytes.
*/
static void
nfsd4_encode_lock_denied(struct nfsd4_compoundres *resp, struct nfsd4_lock_denied *ld)
{
        __be32 *p;

        RESERVE_SPACE(32 + XDR_LEN(ld->ld_sop ? ld->ld_sop->so_owner.len : 0));
        WRITE64(ld->ld_start);
        WRITE64(ld->ld_length);
        WRITE32(ld->ld_type);
        if (ld->ld_sop) {
                WRITEMEM(&ld->ld_clientid, 8);
                WRITE32(ld->ld_sop->so_owner.len);
                WRITEMEM(ld->ld_sop->so_owner.data, ld->ld_sop->so_owner.len);
                kref_put(&ld->ld_sop->so_ref, nfs4_free_stateowner);
        }  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */
                WRITE64((u64)0); /* clientid */
                WRITE32(0); /* length of owner name */
        }
        ADJUST_ARGS();
}

static __be32
nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lock *lock)
{
        ENCODE_SEQID_OP_HEAD;

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

        ENCODE_SEQID_OP_TAIL(lock->lk_replay_owner);
        return nfserr;
}

static __be32
nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lockt *lockt)
{
        if (nfserr == nfserr_denied)
                nfsd4_encode_lock_denied(resp, &lockt->lt_denied);
        return nfserr;
}

static __be32
nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_locku *locku)
{
        ENCODE_SEQID_OP_HEAD;

        if (!nfserr)
                nfsd4_encode_stateid(resp, &locku->lu_stateid);

        ENCODE_SEQID_OP_TAIL(locku->lu_stateowner);
        return nfserr;
}


static __be32
nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_link *link)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(20);
                write_cinfo(&p, &link->li_cinfo);
                ADJUST_ARGS();
        }
        return nfserr;
}


static __be32
nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open *open)
{
        __be32 *p;
        ENCODE_SEQID_OP_HEAD;

        if (nfserr)
                goto out;

        nfsd4_encode_stateid(resp, &open->op_stateid);
        RESERVE_SPACE(40);
        write_cinfo(&p, &open->op_cinfo);
        WRITE32(open->op_rflags);
        WRITE32(2);
        WRITE32(open->op_bmval[0]);
        WRITE32(open->op_bmval[1]);
        WRITE32(open->op_delegate_type);
        ADJUST_ARGS();

        switch (open->op_delegate_type) {
        case NFS4_OPEN_DELEGATE_NONE:
                break;
        case NFS4_OPEN_DELEGATE_READ:
                nfsd4_encode_stateid(resp, &open->op_delegate_stateid);
                RESERVE_SPACE(20);
                WRITE32(open->op_recall);

                /*
                 * TODO: ACE's in delegations
                 */
                WRITE32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
                WRITE32(0);
                WRITE32(0);
                WRITE32(0);   /* XXX: is NULL principal ok? */
                ADJUST_ARGS();
                break;
        case NFS4_OPEN_DELEGATE_WRITE:
                nfsd4_encode_stateid(resp, &open->op_delegate_stateid);
                RESERVE_SPACE(32);
                WRITE32(0);

                /*
                 * TODO: space_limit's in delegations
                 */
                WRITE32(NFS4_LIMIT_SIZE);
                WRITE32(~(u32)0);
                WRITE32(~(u32)0);

                /*
                 * TODO: ACE's in delegations
                 */
                WRITE32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
                WRITE32(0);
                WRITE32(0);
                WRITE32(0);   /* XXX: is NULL principal ok? */
                ADJUST_ARGS();
                break;
        default:
                BUG();
        }
        /* XXX save filehandle here */
out:
        ENCODE_SEQID_OP_TAIL(open->op_stateowner);
        return nfserr;
}

static __be32
nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_confirm *oc)
{
        ENCODE_SEQID_OP_HEAD;

        if (!nfserr)
                nfsd4_encode_stateid(resp, &oc->oc_resp_stateid);

        ENCODE_SEQID_OP_TAIL(oc->oc_stateowner);
        return nfserr;
}

static __be32
nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_downgrade *od)
{
        ENCODE_SEQID_OP_HEAD;

        if (!nfserr)
                nfsd4_encode_stateid(resp, &od->od_stateid);

        ENCODE_SEQID_OP_TAIL(od->od_stateowner);
        return nfserr;
}

static __be32
nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
                  struct nfsd4_read *read)
{
        u32 eof;
        int v, pn;
        unsigned long maxcount; 
        long len;
        __be32 *p;

        if (nfserr)
                return nfserr;
        if (resp->xbuf->page_len)
                return nfserr_resource;

        RESERVE_SPACE(8); /* eof flag and byte count */

        maxcount = svc_max_payload(resp->rqstp);
        if (maxcount > read->rd_length)
                maxcount = read->rd_length;

        len = maxcount;
        v = 0;
        while (len > 0) {
                pn = resp->rqstp->rq_resused++;
                resp->rqstp->rq_vec[v].iov_base =
                        page_address(resp->rqstp->rq_respages[pn]);
                resp->rqstp->rq_vec[v].iov_len =
                        len < PAGE_SIZE ? len : PAGE_SIZE;
                v++;
                len -= PAGE_SIZE;
        }
        read->rd_vlen = v;

        nfserr = nfsd_read_file(read->rd_rqstp, read->rd_fhp, read->rd_filp,
                        read->rd_offset, resp->rqstp->rq_vec, read->rd_vlen,
                        &maxcount);

        if (nfserr == nfserr_symlink)
                nfserr = nfserr_inval;
        if (nfserr)
                return nfserr;
        eof = (read->rd_offset + maxcount >=
               read->rd_fhp->fh_dentry->d_inode->i_size);

        WRITE32(eof);
        WRITE32(maxcount);
        ADJUST_ARGS();
        resp->xbuf->head[0].iov_len = (char*)p
                                        - (char*)resp->xbuf->head[0].iov_base;
        resp->xbuf->page_len = maxcount;

        /* Use rest of head for padding and remaining ops: */
        resp->xbuf->tail[0].iov_base = p;
        resp->xbuf->tail[0].iov_len = 0;
        if (maxcount&3) {
                RESERVE_SPACE(4);
                WRITE32(0);
                resp->xbuf->tail[0].iov_base += maxcount&3;
                resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
                ADJUST_ARGS();
        }
        return 0;
}

static __be32
nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readlink *readlink)
{
        int maxcount;
        char *page;
        __be32 *p;

        if (nfserr)
                return nfserr;
        if (resp->xbuf->page_len)
                return nfserr_resource;

        page = page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused++]);

        maxcount = PAGE_SIZE;
        RESERVE_SPACE(4);

        /*
         * XXX: By default, the ->readlink() VFS op will truncate symlinks
         * if they would overflow the buffer.  Is this kosher in NFSv4?  If
         * not, one easy fix is: if ->readlink() precisely fills the buffer,
         * assume that truncation occurred, and return NFS4ERR_RESOURCE.
         */
        nfserr = nfsd_readlink(readlink->rl_rqstp, readlink->rl_fhp, page, &maxcount);
        if (nfserr == nfserr_isdir)
                return nfserr_inval;
        if (nfserr)
                return nfserr;

        WRITE32(maxcount);
        ADJUST_ARGS();
        resp->xbuf->head[0].iov_len = (char*)p
                                - (char*)resp->xbuf->head[0].iov_base;
        resp->xbuf->page_len = maxcount;

        /* Use rest of head for padding and remaining ops: */
        resp->xbuf->tail[0].iov_base = p;
        resp->xbuf->tail[0].iov_len = 0;
        if (maxcount&3) {
                RESERVE_SPACE(4);
                WRITE32(0);
                resp->xbuf->tail[0].iov_base += maxcount&3;
                resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
                ADJUST_ARGS();
        }
        return 0;
}

static __be32
nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readdir *readdir)
{
        int maxcount;
        loff_t offset;
        __be32 *page, *savep, *tailbase;
        __be32 *p;

        if (nfserr)
                return nfserr;
        if (resp->xbuf->page_len)
                return nfserr_resource;

        RESERVE_SPACE(8);  /* verifier */
        savep = p;

        /* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
        WRITE32(0);
        WRITE32(0);
        ADJUST_ARGS();
        resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base;
        tailbase = p;

        maxcount = PAGE_SIZE;
        if (maxcount > readdir->rd_maxcount)
                maxcount = readdir->rd_maxcount;

        /*
         * Convert from bytes to words, account for the two words already
         * written, make sure to leave two words at the end for the next
         * pointer and eof field.
         */
        maxcount = (maxcount >> 2) - 4;
        if (maxcount < 0) {
                nfserr =  nfserr_toosmall;
                goto err_no_verf;
        }

        page = page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused++]);
        readdir->common.err = 0;
        readdir->buflen = maxcount;
        readdir->buffer = page;
        readdir->offset = NULL;

        offset = readdir->rd_cookie;
        nfserr = nfsd_readdir(readdir->rd_rqstp, readdir->rd_fhp,
                              &offset,
                              &readdir->common, nfsd4_encode_dirent);
        if (nfserr == nfs_ok &&
            readdir->common.err == nfserr_toosmall &&
            readdir->buffer == page) 
                nfserr = nfserr_toosmall;
        if (nfserr == nfserr_symlink)
                nfserr = nfserr_notdir;
        if (nfserr)
                goto err_no_verf;

        if (readdir->offset)
                xdr_encode_hyper(readdir->offset, offset);

        p = readdir->buffer;
        *p++ = 0;       /* no more entries */
        *p++ = htonl(readdir->common.err == nfserr_eof);
        resp->xbuf->page_len = ((char*)p) - (char*)page_address(
                resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);

        /* Use rest of head for padding and remaining ops: */
        resp->xbuf->tail[0].iov_base = tailbase;
        resp->xbuf->tail[0].iov_len = 0;
        resp->p = resp->xbuf->tail[0].iov_base;
        resp->end = resp->p + (PAGE_SIZE - resp->xbuf->head[0].iov_len)/4;

        return 0;
err_no_verf:
        p = savep;
        ADJUST_ARGS();
        return nfserr;
}

static __be32
nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_remove *remove)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(20);
                write_cinfo(&p, &remove->rm_cinfo);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32
nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_rename *rename)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(40);
                write_cinfo(&p, &rename->rn_sinfo);
                write_cinfo(&p, &rename->rn_tinfo);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32
nfsd4_do_encode_secinfo(struct nfsd4_compoundres *resp,
                         __be32 nfserr,struct svc_export *exp)
{
        int i = 0;
        u32 nflavs;
        struct exp_flavor_info *flavs;
        struct exp_flavor_info def_flavs[2];
        __be32 *p;

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

        RESERVE_SPACE(4);
        WRITE32(nflavs);
        ADJUST_ARGS();
        for (i = 0; i < nflavs; i++) {
                u32 flav = flavs[i].pseudoflavor;
                struct gss_api_mech *gm = gss_mech_get_by_pseudoflavor(flav);

                if (gm) {
                        RESERVE_SPACE(4);
                        WRITE32(RPC_AUTH_GSS);
                        ADJUST_ARGS();
                        RESERVE_SPACE(4 + gm->gm_oid.len);
                        WRITE32(gm->gm_oid.len);
                        WRITEMEM(gm->gm_oid.data, gm->gm_oid.len);
                        ADJUST_ARGS();
                        RESERVE_SPACE(4);
                        WRITE32(0); /* qop */
                        ADJUST_ARGS();
                        RESERVE_SPACE(4);
                        WRITE32(gss_pseudoflavor_to_service(gm, flav));
                        ADJUST_ARGS();
                        gss_mech_put(gm);
                } else {
                        RESERVE_SPACE(4);
                        WRITE32(flav);
                        ADJUST_ARGS();
                }
        }
out:
        if (exp)
                exp_put(exp);
        return nfserr;
}

static __be32
nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
                     struct nfsd4_secinfo *secinfo)
{
        return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->si_exp);
}

static __be32
nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
                     struct nfsd4_secinfo_no_name *secinfo)
{
        return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->sin_exp);
}

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

        RESERVE_SPACE(12);
        if (nfserr) {
                WRITE32(2);
                WRITE32(0);
                WRITE32(0);
        }
        else {
                WRITE32(2);
                WRITE32(setattr->sa_bmval[0]);
                WRITE32(setattr->sa_bmval[1]);
        }
        ADJUST_ARGS();
        return nfserr;
}

static __be32
nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(8 + sizeof(nfs4_verifier));
                WRITEMEM(&scd->se_clientid, 8);
                WRITEMEM(&scd->se_confirm, sizeof(nfs4_verifier));
                ADJUST_ARGS();
        }
        else if (nfserr == nfserr_clid_inuse) {
                RESERVE_SPACE(8);
                WRITE32(0);
                WRITE32(0);
                ADJUST_ARGS();
        }
        return nfserr;
}

static __be32
nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_write *write)
{
        __be32 *p;

        if (!nfserr) {
                RESERVE_SPACE(16);
                WRITE32(write->wr_bytes_written);
                WRITE32(write->wr_how_written);