nfs4xdr.c

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/*
 *  Server-side XDR for NFSv4
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <[email protected]>
 *  Andy Adamson   <[email protected]>
 *
 *  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/pagemap.h>
#include <linux/sunrpc/svcauth_gss.h>

#include "idmap.h"
#include "acl.h"
#include "xdr4.h"
#include "vfs.h"
#include "state.h"
#include "cache.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 = kmemdup(argp->tmp, nbytes, GFP_KERNEL);
        if (!p)
            return NULL;
    } 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;

    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;

    /*
    * 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;

    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_share_access(struct nfsd4_compoundargs *argp, u32 *share_access, u32 *deleg_want, u32 *deleg_when)
{
    __be32 *p;
    u32 w;

    READ_BUF(4);
    READ32(w);
    *share_access = w & NFS4_SHARE_ACCESS_MASK;
    *deleg_want = w & NFS4_SHARE_WANT_MASK;
    if (deleg_when)
        *deleg_when = w & NFS4_SHARE_WHEN_MASK;

    switch (w & NFS4_SHARE_ACCESS_MASK) {
    case NFS4_SHARE_ACCESS_READ:
    case NFS4_SHARE_ACCESS_WRITE:
    case NFS4_SHARE_ACCESS_BOTH:
        break;
    default:
        return nfserr_bad_xdr;
    }
    w &= ~NFS4_SHARE_ACCESS_MASK;
    if (!w)
        return nfs_ok;
    if (!argp->minorversion)
        return nfserr_bad_xdr;
    switch (w & NFS4_SHARE_WANT_MASK) {
    case NFS4_SHARE_WANT_NO_PREFERENCE:
    case NFS4_SHARE_WANT_READ_DELEG:
    case NFS4_SHARE_WANT_WRITE_DELEG:
    case NFS4_SHARE_WANT_ANY_DELEG:
    case NFS4_SHARE_WANT_NO_DELEG:
    case NFS4_SHARE_WANT_CANCEL:
        break;
    default:
        return nfserr_bad_xdr;
    }
    w &= ~NFS4_SHARE_WANT_MASK;
    if (!w)
        return nfs_ok;

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

static __be32 nfsd4_decode_share_deny(struct nfsd4_compoundargs *argp, u32 *x)
{
    __be32 *p;

    READ_BUF(4);
    READ32(*x);
    /* Note: unlinke access bits, deny bits may be zero. */
    if (*x & ~NFS4_SHARE_DENY_BOTH)
        return nfserr_bad_xdr;
    return nfs_ok;
xdr_error:
    return nfserr_bad_xdr;
}

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

    READ_BUF(4);
    READ32(o->len);

    if (o->len == 0 || o->len > NFS4_OPAQUE_LIMIT)
        return nfserr_bad_xdr;

    READ_BUF(o->len);
    SAVEMEM(o->data, o->len);
    return nfs_ok;
xdr_error:
    return nfserr_bad_xdr;
}

static __be32
nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
{
    DECODE_HEAD;
    u32 dummy;

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

    /* seqid, share_access, share_deny, clientid, ownerlen */
    READ_BUF(4);
    READ32(open->op_seqid);
    /* decode, yet ignore deleg_when until supported */
    status = nfsd4_decode_share_access(argp, &open->op_share_access,
                       &open->op_deleg_want, &dummy);
    if (status)
        goto xdr_error;
    status = nfsd4_decode_share_deny(argp, &open->op_share_deny);
    if (status)
        goto xdr_error;
    READ_BUF(sizeof(clientid_t));
    COPYMEM(&open->op_clientid, sizeof(clientid_t));
    status = nfsd4_decode_opaque(argp, &open->op_owner);
    if (status)
        goto xdr_error;
    READ_BUF(4);
    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(NFS4_VERIFIER_SIZE);
            COPYMEM(open->op_verf.data, NFS4_VERIFIER_SIZE);
            break;
        case NFS4_CREATE_EXCLUSIVE4_1:
            if (argp->minorversion < 1)
                goto xdr_error;
            READ_BUF(NFS4_VERIFIER_SIZE);
            COPYMEM(open->op_verf.data, NFS4_VERIFIER_SIZE);
            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;
    case NFS4_OPEN_CLAIM_FH:
    case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
        if (argp->minorversion < 1)
            goto xdr_error;
        /* void */
        break;
    case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
        if (argp->minorversion < 1)
            goto xdr_error;
        status = nfsd4_decode_stateid(argp, &open->op_delegate_stateid);
        if (status)
            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;
            
    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;
            
    status = nfsd4_decode_stateid(argp, &open_down->od_stateid);
    if (status)
        return status;
    READ_BUF(4);
    READ32(open_down->od_seqid);
    status = nfsd4_decode_share_access(argp, &open_down->od_share_access,
                       &open_down->od_deleg_want, NULL);
    if (status)
        return status;
    status = nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
    if (status)
        return status;
    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(NFS4_VERIFIER_SIZE);
    COPYMEM(setclientid->se_verf.data, NFS4_VERIFIER_SIZE);

    status = nfsd4_decode_opaque(argp, &setclientid->se_name);
    if (status)
        return nfserr_bad_xdr;
    READ_BUF(8);
    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 + NFS4_VERIFIER_SIZE);
    COPYMEM(&scd_c->sc_clientid, 8);
    COPYMEM(&scd_c->sc_confirm, NFS4_VERIFIER_SIZE);

    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);

    status = nfsd4_decode_opaque(argp, &exid->clname);
    if (status)
        return nfserr_bad_xdr;

    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_free_stateid(struct nfsd4_compoundargs *argp,
              struct nfsd4_free_stateid *free_stateid)
{
    DECODE_HEAD;

    READ_BUF(sizeof(stateid_t));
    READ32(free_stateid->fr_stateid.si_generation);
    COPYMEM(&free_stateid->fr_stateid.si_opaque, sizeof(stateid_opaque_t));

    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_test_stateid(struct nfsd4_compoundargs *argp, struct nfsd4_test_stateid *test_stateid)
{
    int i;
    __be32 *p, status;
    struct nfsd4_test_stateid_id *stateid;

    READ_BUF(4);
    test_stateid->ts_num_ids = ntohl(*p++);

    INIT_LIST_HEAD(&test_stateid->ts_stateid_list);

    for (i = 0; i < test_stateid->ts_num_ids; i++) {
        stateid = kmalloc(sizeof(struct nfsd4_test_stateid_id), GFP_KERNEL);
        if (!stateid) {
            status = nfserrno(-ENOMEM);
            goto out;
        }

        defer_free(argp, kfree, stateid);
        INIT_LIST_HEAD(&stateid->ts_id_list);
        list_add_tail(&stateid->ts_id_list, &test_stateid->ts_stateid_list);

        status = nfsd4_decode_stateid(argp, &stateid->ts_id_stateid);
        if (status)
            goto out;
    }

    status = 0;
out:
    return status;
xdr_error:
    dprintk("NFSD: xdr error (%s:%d)\n", __FILE__, __LINE__);
    status = nfserr_bad_xdr;
    goto out;
}

static __be32 nfsd4_decode_destroy_clientid(struct nfsd4_compoundargs *argp, struct nfsd4_destroy_clientid *dc)
{
    DECODE_HEAD;

    READ_BUF(8);
    COPYMEM(&dc->clientid, 8);

    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_free_stateid,
    [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_test_stateid,
    [OP_WANT_DELEGATION]    = (nfsd4_dec)nfsd4_decode_notsupp,
    [OP_DESTROY_CLIENTID]   = (nfsd4_dec)nfsd4_decode_destroy_clientid,
    [OP_RECLAIM_COMPLETE]   = (nfsd4_dec)nfsd4_decode_reclaim_complete,
};

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;
    bool cachethis = false;
    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;
        }
        /*
         * We'll try to cache the result in the DRC if any one
         * op in the compound wants to be cached:
         */
        cachethis |= nfsd4_cache_this_op(op);
    }
    /* Sessions make the DRC unnecessary: */
    if (argp->minorversion)
        cachethis = false;
    argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE;

    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)++ = htonl(n);
}

static void write64(__be32 **p, u64 n)
{
    write32(p, (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.
 */

static void encode_seqid_op_tail(struct nfsd4_compoundres *resp, __be32 *save, __be32 nfserr)
{
    struct nfs4_stateowner *stateowner = resp->cstate.replay_owner;

    if (seqid_mutating_err(ntohl(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);
        nfsd4_purge_closed_stateid(stateowner);
    }
}

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

    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) {
        bool found_esc = false;

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

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

        strlen = end - str;
        if (strlen) {
            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 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)
{
    return nfsd4_encode_components_esc(sep, components, pp, buflen, 0, 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_esc(':', location->hosts, &p, buflen,
                        '[', ']');
    if (status)
        return status;
    status = nfsd4_encode_components('/', location->path, &p, buflen);
    if (status)
        return status;
    *pp = p;
    return 0;
}

/*
 * Encode a path in RFC3530 'pathname4' format
 */
static __be32 nfsd4_encode_path(const struct path *root,
        const struct path *path, __be32 **pp, int *buflen)
{
    struct path cur = {
        .mnt = path->mnt,
        .dentry = path->dentry,
    };
    __be32 *p = *pp;
    struct dentry **components = NULL;
    unsigned int ncomponents = 0;
    __be32 err = nfserr_jukebox;

    dprintk("nfsd4_encode_components(");

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

    *buflen -= 4;
    if (*buflen < 0)
        goto out_free;
    WRITE32(ncomponents);

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

        *buflen -= 4 + (XDR_QUADLEN(len) << 2);
        if (*buflen < 0)
            goto out_free;
        WRITE32(len);
        WRITEMEM(dentry->d_name.name, len);
        dprintk("/%s", dentry->d_name.name);
        dput(dentry);
        ncomponents--;
    }

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

static __be32 nfsd4_encode_fsloc_fsroot(struct svc_rqst *rqstp,
        const struct path *path, __be32 **pp, int *buflen)
{
    struct svc_export *exp_ps;
    __be32 res;

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

/*
 *  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;

    status = nfsd4_encode_fsloc_fsroot(rqstp, &exp->ex_path, &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_file_type(umode_t mode)
{
    switch (mode & S_IFMT) {
    case S_IFIFO:   return NF4FIFO;
    case S_IFCHR:   return NF4CHR;
    case S_IFDIR:   return NF4DIR;
    case S_IFBLK:   return NF4BLK;
    case S_IFLNK:   return NF4LNK;
    case S_IFREG:   return NF4REG;
    case S_IFSOCK:  return NF4SOCK;
    default:    return NF4BAD;
    };
}

static __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_file_type(stat.mode);
        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(0);
    }
    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);
        /* Sorry, we do not yet support RDMA over 4.1: */
        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(resp, save, nfserr);
    return nfserr;
}


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

    if (!nfserr) {
        RESERVE_SPACE(NFS4_VERIFIER_SIZE);
        WRITEMEM(commit->co_verf.data, NFS4_VERIFIER_SIZE);
        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)
{
    struct xdr_netobj *conf = &ld->ld_owner;
    __be32 *p;

    RESERVE_SPACE(32 + XDR_LEN(conf->len));
    WRITE64(ld->ld_start);
    WRITE64(ld->ld_length);
    WRITE32(ld->ld_type);
    if (conf->len) {
        WRITEMEM(&ld->ld_clientid, 8);
        WRITE32(conf->len);
        WRITEMEM(conf->data, conf->len);
        kfree(conf->data);
    }  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(resp, save, nfserr);
    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(resp, save, nfserr);
    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;
    case NFS4_OPEN_DELEGATE_NONE_EXT: /* 4.1 */
        switch (open->op_why_no_deleg) {
        case WND4_CONTENTION:
        case WND4_RESOURCE:
            RESERVE_SPACE(8);
            WRITE32(open->op_why_no_deleg);
            WRITE32(0); /* deleg signaling not supported yet */
            break;
        default:
            RESERVE_SPACE(4);
            WRITE32(open->op_why_no_deleg);
        }
        ADJUST_ARGS();
        break;
    default:
        BUG();
    }
    /* XXX save filehandle here */
out:
    encode_seqid_op_tail(resp, save, nfserr);
    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(resp, save, nfserr);
    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(resp, save, nfserr);
    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)
        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(NFS4_VERIFIER_SIZE);
    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)
        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 + NFS4_VERIFIER_SIZE);
        WRITEMEM(&scd->se_clientid, 8);
        WRITEMEM(&scd->se_confirm, NFS4_VERIFIER_SIZE);
        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);
        WRITEMEM(write->wr_verifier.data, NFS4_VERIFIER_SIZE);
        ADJUST_ARGS();
    }
    return nfserr;
}

static __be32
nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
             struct nfsd4_exchange_id *exid)
{
    __be32 *p;
    char *major_id;
    char *server_scope;
    int major_id_sz;
    int server_scope_sz;
    uint64_t minor_id = 0;

    if (nfserr)
        return nfserr;

    major_id = utsname()->nodename;
    major_id_sz = strlen(major_id);
    server_scope = utsname()->nodename;
    server_scope_sz = strlen(server_scope);

    RESERVE_SPACE(
        8 /* eir_clientid */ +
        4 /* eir_sequenceid */ +
        4 /* eir_flags */ +
        4 /* spr_how (SP4_NONE) */ +
        8 /* so_minor_id */ +
        4 /* so_major_id.len */ +
        (XDR_QUADLEN(major_id_sz) * 4) +
        4 /* eir_server_scope.len */ +
        (XDR_QUADLEN(server_scope_sz) * 4) +
        4 /* eir_server_impl_id.count (0) */);

    WRITEMEM(&exid->clientid, 8);
    WRITE32(exid->seqid);
    WRITE32(exid->flags);

    /* state_protect4_r. Currently only support SP4_NONE */
    BUG_ON(exid->spa_how != SP4_NONE);
    WRITE32(exid->spa_how);

    /* The server_owner struct */
    WRITE64(minor_id);      /* Minor id */
    /* major id */
    WRITE32(major_id_sz);
    WRITEMEM(major_id, major_id_sz);

    /* Server scope */
    WRITE32(server_scope_sz);
    WRITEMEM(server_scope, server_scope_sz);

    /* Implementation id */
    WRITE32(0); /* zero length nfs_impl_id4 array */
    ADJUST_ARGS();
    return 0;
}

static __be32
nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
                struct nfsd4_create_session *sess)
{
    __be32 *p;

    if (nfserr)
        return nfserr;

    RESERVE_SPACE(24);
    WRITEMEM(sess->sessionid.data, NFS4_MAX_SESSIONID_LEN);
    WRITE32(sess->seqid);
    WRITE32(sess->flags);
    ADJUST_ARGS();

    RESERVE_SPACE(28);
    WRITE32(0); /* headerpadsz */
    WRITE32(sess->fore_channel.maxreq_sz);
    WRITE32(sess->fore_channel.maxresp_sz);
    WRITE32(sess->fore_channel.maxresp_cached);
    WRITE32(sess->fore_channel.maxops);
    WRITE32(sess->fore_channel.maxreqs);
    WRITE32(sess->fore_channel.nr_rdma_attrs);
    ADJUST_ARGS();

    if (sess->fore_channel.nr_rdma_attrs) {
        RESERVE_SPACE(4);
        WRITE32(sess->fore_channel.rdma_attrs);
        ADJUST_ARGS();
    }

    RESERVE_SPACE(28);
    WRITE32(0); /* headerpadsz */
    WRITE32(sess->back_channel.maxreq_sz);
    WRITE32(sess->back_channel.maxresp_sz);
    WRITE32(sess->back_channel.maxresp_cached);
    WRITE32(sess->back_channel.maxops);
    WRITE32(sess->back_channel.maxreqs);
    WRITE32(sess->back_channel.nr_rdma_attrs);
    ADJUST_ARGS();

    if (sess->back_channel.nr_rdma_attrs) {
        RESERVE_SPACE(4);
        WRITE32(sess->back_channel.rdma_attrs);
        ADJUST_ARGS();
    }
    return 0;
}

static __be32
nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, __be32 nfserr,
                 struct nfsd4_destroy_session *destroy_session)
{
    return nfserr;
}

static __be32
nfsd4_encode_free_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
              struct nfsd4_free_stateid *free_stateid)
{
    __be32 *p;

    if (nfserr)
        return nfserr;

    RESERVE_SPACE(4);
    *p++ = nfserr;
    ADJUST_ARGS();
    return nfserr;
}

static __be32
nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
              struct nfsd4_sequence *seq)
{
    __be32 *p;

    if (nfserr)
        return nfserr;

    RESERVE_SPACE(NFS4_MAX_SESSIONID_LEN + 20);
    WRITEMEM(seq->sessionid.data, NFS4_MAX_SESSIONID_LEN);
    WRITE32(seq->seqid);
    WRITE32(seq->slotid);
    /* Note slotid's are numbered from zero: */
    WRITE32(seq->maxslots - 1); /* sr_highest_slotid */
    WRITE32(seq->maxslots - 1); /* sr_target_highest_slotid */
    WRITE32(seq->status_flags);

    ADJUST_ARGS();
    resp->cstate.datap = p; /* DRC cache data pointer */
    return 0;
}

static __be32
nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
              struct nfsd4_test_stateid *test_stateid)
{
    struct nfsd4_test_stateid_id *stateid, *next;
    __be32 *p;

    RESERVE_SPACE(4 + (4 * test_stateid->ts_num_ids));
    *p++ = htonl(test_stateid->ts_num_ids);

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

    ADJUST_ARGS();
    return nfserr;
}

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

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

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

    /* NFSv4.1 operations */
    [OP_BACKCHANNEL_CTL]    = (nfsd4_enc)nfsd4_encode_noop,
    [OP_BIND_CONN_TO_SESSION] = (nfsd4_enc)nfsd4_encode_bind_conn_to_session,
    [OP_EXCHANGE_ID]    = (nfsd4_enc)nfsd4_encode_exchange_id,
    [OP_CREATE_SESSION] = (nfsd4_enc)nfsd4_encode_create_session,
    [OP_DESTROY_SESSION]    = (nfsd4_enc)nfsd4_encode_destroy_session,
    [OP_FREE_STATEID]   = (nfsd4_enc)nfsd4_encode_free_stateid,
    [OP_GET_DIR_DELEGATION] = (nfsd4_enc)nfsd4_encode_noop,
    [OP_GETDEVICEINFO]  = (nfsd4_enc)nfsd4_encode_noop,
    [OP_GETDEVICELIST]  = (nfsd4_enc)nfsd4_encode_noop,
    [OP_LAYOUTCOMMIT]   = (nfsd4_enc)nfsd4_encode_noop,
    [OP_LAYOUTGET]      = (nfsd4_enc)nfsd4_encode_noop,
    [OP_LAYOUTRETURN]   = (nfsd4_enc)nfsd4_encode_noop,
    [OP_SECINFO_NO_NAME]    = (nfsd4_enc)nfsd4_encode_secinfo_no_name,
    [OP_SEQUENCE]       = (nfsd4_enc)nfsd4_encode_sequence,
    [OP_SET_SSV]        = (nfsd4_enc)nfsd4_encode_noop,
    [OP_TEST_STATEID]   = (nfsd4_enc)nfsd4_encode_test_stateid,
    [OP_WANT_DELEGATION]    = (nfsd4_enc)nfsd4_encode_noop,
    [OP_DESTROY_CLIENTID]   = (nfsd4_enc)nfsd4_encode_noop,
    [OP_RECLAIM_COMPLETE]   = (nfsd4_enc)nfsd4_encode_noop,
};

/*
 * Calculate the total amount of memory that the compound response has taken
 * after encoding the current operation with pad.
 *
 * pad: if operation is non-idempotent, pad was calculate by op_rsize_bop()
 *      which was specified at nfsd4_operation, else pad is zero.
 *
 * Compare this length to the session se_fmaxresp_sz and se_fmaxresp_cached.
 *
 * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so
 * will be at least a page and will therefore hold the xdr_buf head.
 */
__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 pad)
{
    struct xdr_buf *xb = &resp->rqstp->rq_res;
    struct nfsd4_session *session = NULL;
    struct nfsd4_slot *slot = resp->cstate.slot;
    u32 length, tlen = 0;

    if (!nfsd4_has_session(&resp->cstate))
        return 0;

    session = resp->cstate.session;
    if (session == NULL)
        return 0;

    if (xb->page_len == 0) {
        length = (char *)resp->p - (char *)xb->head[0].iov_base + pad;
    } else {
        if (xb->tail[0].iov_base && xb->tail[0].iov_len > 0)
            tlen = (char *)resp->p - (char *)xb->tail[0].iov_base;

        length = xb->head[0].iov_len + xb->page_len + tlen + pad;
    }
    dprintk("%s length %u, xb->page_len %u tlen %u pad %u\n", __func__,
        length, xb->page_len, tlen, pad);

    if (length > session->se_fchannel.maxresp_sz)
        return nfserr_rep_too_big;

    if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) &&
        length > session->se_fchannel.maxresp_cached)
        return nfserr_rep_too_big_to_cache;

    return 0;
}

void
nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
    __be32 *statp;
    __be32 *p;

    RESERVE_SPACE(8);
    WRITE32(op->opnum);
    statp = p++;    /* to be backfilled at the end */
    ADJUST_ARGS();

    if (op->opnum == OP_ILLEGAL)
        goto status;
    BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
           !nfsd4_enc_ops[op->opnum]);
    op->status = nfsd4_enc_ops[op->opnum](resp, op->status, &op->u);
    /* nfsd4_check_drc_limit guarantees enough room for error status */
    if (!op->status)
        op->status = nfsd4_check_resp_size(resp, 0);
status:
    /*
     * Note: We write the status directly, instead of using WRITE32(),
     * since it is already in network byte order.
     */
    *statp = op->status;
}

/* 
 * Encode the reply stored in the stateowner reply cache 
 * 
 * XDR note: do not encode rp->rp_buflen: the buffer contains the
 * previously sent already encoded operation.
 *
 * called with nfs4_lock_state() held
 */
void
nfsd4_encode_replay(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
    __be32 *p;
    struct nfs4_replay *rp = op->replay;

    BUG_ON(!rp);

    RESERVE_SPACE(8);
    WRITE32(op->opnum);
    *p++ = rp->rp_status;  /* already xdr'ed */
    ADJUST_ARGS();

    RESERVE_SPACE(rp->rp_buflen);
    WRITEMEM(rp->rp_buf, rp->rp_buflen);
    ADJUST_ARGS();
}

int
nfs4svc_encode_voidres(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
        return xdr_ressize_check(rqstp, p);
}

int nfsd4_release_compoundargs(void *rq, __be32 *p, void *resp)
{
    struct svc_rqst *rqstp = rq;
    struct nfsd4_compoundargs *args = rqstp->rq_argp;

    if (args->ops != args->iops) {
        kfree(args->ops);
        args->ops = args->iops;
    }
    kfree(args->tmpp);
    args->tmpp = NULL;
    while (args->to_free) {
        struct tmpbuf *tb = args->to_free;
        args->to_free = tb->next;
        tb->release(tb->buf);
        kfree(tb);
    }
    return 1;
}

int
nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compoundargs *args)
{
    args->p = p;
    args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len;
    args->pagelist = rqstp->rq_arg.pages;
    args->pagelen = rqstp->rq_arg.page_len;
    args->tmpp = NULL;
    args->to_free = NULL;
    args->ops = args->iops;
    args->rqstp = rqstp;

    return !nfsd4_decode_compound(args);
}

int
nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compoundres *resp)
{
    /*
     * All that remains is to write the tag and operation count...
     */
    struct nfsd4_compound_state *cs = &resp->cstate;
    struct kvec *iov;
    p = resp->tagp;
    *p++ = htonl(resp->taglen);
    memcpy(p, resp->tag, resp->taglen);
    p += XDR_QUADLEN(resp->taglen);
    *p++ = htonl(resp->opcnt);

    if (rqstp->rq_res.page_len) 
        iov = &rqstp->rq_res.tail[0];
    else
        iov = &rqstp->rq_res.head[0];
    iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
    BUG_ON(iov->iov_len > PAGE_SIZE);
    if (nfsd4_has_session(cs)) {
        if (cs->status != nfserr_replay_cache) {
            nfsd4_store_cache_entry(resp);
            cs->slot->sl_flags &= ~NFSD4_SLOT_INUSE;
        }
        /* Renew the clientid on success and on replay */
        release_session_client(cs->session);
        nfsd4_put_session(cs->session);
    }
    return 1;
}

/*
 * Local variables:
 *  c-basic-offset: 8
 * End:
 */