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nfs4xdr.c

/*
 *  fs/nfs/nfs4xdr.c
 *
 *  Server-side XDR for NFSv4
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * 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/param.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>
#include <linux/nfsd_idmap.h>
#include <linux/nfs4.h>
#include <linux/nfs4_acl.h>

#define NFSDDBG_FACILITY            NFSDDBG_XDR

static int
check_filename(char *str, int len, int 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;
}

/*
 * START OF "GENERIC" DECODE ROUTINES.
 *   These may look a little ugly since they are imported from a "generic"
 * set of XDR encode/decode routines which are intended to be shared by
 * all of our NFSv4 implementations (OpenBSD, MacOS X...).
 *
 * If the pain of reading these is too great, it should be a straightforward
 * task to translate them into Linux-specific versions which are more
 * consistent with the style used in NFSv2/v3...
 */
#define DECODE_HEAD                       \
      u32 *p;                             \
      int status
#define DECODE_TAIL                       \
      status = 0;                   \
out:                                \
      return status;                      \
xdr_error:                          \
      printk(KERN_NOTICE "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)) {                 \
            printk(KERN_NOTICE "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))) { \
            printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__); \
            goto xdr_error;               \
      }                             \
} while (0)

static u32 *read_buf(struct nfsd4_compoundargs *argp, int nbytes)
{
      /* We want more bytes than seem to be available.
       * Maybe we need a new page, maybe we have just run out
       */
      int avail = (char*)argp->end - (char*)argp->p;
      u32 *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;
            
      }
      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 = p + (argp->pagelen>>2);
            argp->pagelen = 0;
      } else {
            argp->end = 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
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, u32 *p, int nbytes)
{
      void *new = NULL;
      if (p == argp->tmp) {
            new = kmalloc(nbytes, GFP_KERNEL);
            if (!new) return NULL;
            p = new;
            memcpy(p, argp->tmp, nbytes);
      } else {
            if (p != argp->tmpp)
                  BUG();
            argp->tmpp = NULL;
      }
      if (defer_free(argp, kfree, p)) {
            kfree(new);
            return NULL;
      } else
            return (char *)p;
}


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

      bmval[0] = 0;
      bmval[1] = 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]);

      DECODE_TAIL;
}

static int
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;

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

      /*
       * According to spec, unsupported attributes return ERR_NOTSUPP;
       * read-only attributes return ERR_INVAL.
       */
      if ((bmval[0] & ~NFSD_SUPPORTED_ATTRS_WORD0) || (bmval[1] & ~NFSD_SUPPORTED_ATTRS_WORD1))
            return nfserr_attrnotsupp;
      if ((bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0) || (bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1))
            return nfserr_inval;

      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, i;
            struct nfs4_ace ace;

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

            *acl = nfs4_acl_new();
            if (*acl == NULL) {
                  status = -ENOMEM;
                  goto out_nfserr;
            }
            defer_free(argp, (void (*)(const void *))nfs4_acl_free, *acl);

            for (i = 0; i < nace; i++) {
                  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 = 0;
                  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)
                        goto out_nfserr;
                  status = nfs4_acl_add_ace(*acl, ace.type, ace.flag,
                         ace.access_mask, ace.whotype, ace.who);
                  if (status)
                        goto out_nfserr;
            }
      } 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)))
                  goto out_nfserr;
            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)))
                  goto out_nfserr;
            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_METADATA) {
            /* 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_ctime.tv_sec);
            READ32(iattr->ia_ctime.tv_nsec);
            if (iattr->ia_ctime.tv_nsec >= (u32)1000000000)
                  return nfserr_inval;
            iattr->ia_valid |= ATTR_CTIME;
      }
      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 (len != expected_len)
            goto xdr_error;

      DECODE_TAIL;

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

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

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

      DECODE_TAIL;
}

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

      close->cl_stateowner = NULL;
      READ_BUF(4 + sizeof(stateid_t));
      READ32(close->cl_seqid);
      READ32(close->cl_stateid.si_generation);
      COPYMEM(&close->cl_stateid.si_opaque, sizeof(stateid_opaque_t));

      DECODE_TAIL;
}


static int
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 int
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;

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

      DECODE_TAIL;
}

static inline int
nfsd4_decode_delegreturn(struct nfsd4_compoundargs *argp, struct nfsd4_delegreturn *dr)
{
      DECODE_HEAD;

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

      DECODE_TAIL;
}

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

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

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

      if (lock->lk_is_new) {
            READ_BUF(36);
            READ32(lock->lk_new_open_seqid);
            READ32(lock->lk_new_open_stateid.si_generation);

            COPYMEM(&lock->lk_new_open_stateid.si_opaque, sizeof(stateid_opaque_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 {
            READ_BUF(20);
            READ32(lock->lk_old_lock_stateid.si_generation);
            COPYMEM(&lock->lk_old_lock_stateid.si_opaque, sizeof(stateid_opaque_t));
            READ32(lock->lk_old_lock_seqid);
      }

      DECODE_TAIL;
}

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

      locku->lu_stateowner = NULL;
      READ_BUF(24 + sizeof(stateid_t));
      READ32(locku->lu_type);
      if ((locku->lu_type < NFS4_READ_LT) || (locku->lu_type > NFS4_WRITEW_LT))
            goto xdr_error;
      READ32(locku->lu_seqid);
      READ32(locku->lu_stateid.si_generation);
      COPYMEM(&locku->lu_stateid.si_opaque, sizeof(stateid_opaque_t));
      READ64(locku->lu_offset);
      READ64(locku->lu_length);

      DECODE_TAIL;
}

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

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

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

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

      DECODE_TAIL;
}

static int
nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_open_confirm *open_conf)
{
      DECODE_HEAD;
                
      open_conf->oc_stateowner = NULL;
      READ_BUF(4 + sizeof(stateid_t));
      READ32(open_conf->oc_req_stateid.si_generation);
      COPYMEM(&open_conf->oc_req_stateid.si_opaque, sizeof(stateid_opaque_t));
      READ32(open_conf->oc_seqid);
                                            
      DECODE_TAIL;
}

static int
nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
{
      DECODE_HEAD;
                
      open_down->od_stateowner = NULL;
      READ_BUF(12 + sizeof(stateid_t));
      READ32(open_down->od_stateid.si_generation);
      COPYMEM(&open_down->od_stateid.si_opaque, sizeof(stateid_opaque_t));
      READ32(open_down->od_seqid);
      READ32(open_down->od_share_access);
      READ32(open_down->od_share_deny);
                                            
      DECODE_TAIL;
}

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

      READ_BUF(sizeof(stateid_t) + 12);
      READ32(read->rd_stateid.si_generation);
      COPYMEM(&read->rd_stateid.si_opaque, sizeof(stateid_opaque_t));
      READ64(read->rd_offset);
      READ32(read->rd_length);

      DECODE_TAIL;
}

static int
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 int
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 int
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 int
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 int
nfsd4_decode_setattr(struct nfsd4_compoundargs *argp, struct nfsd4_setattr *setattr)
{
      DECODE_HEAD;

      READ_BUF(sizeof(stateid_t));
      READ32(setattr->sa_stateid.si_generation);
      COPYMEM(&setattr->sa_stateid.si_opaque, sizeof(stateid_opaque_t));
      if ((status = nfsd4_decode_fattr(argp, setattr->sa_bmval, &setattr->sa_iattr, &setattr->sa_acl)))
            goto out;

      DECODE_TAIL;
}

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

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

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

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

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

      DECODE_TAIL;
}

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

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

      DECODE_TAIL;
}

/* Also used for NVERIFY */
static int
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 int
nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
{
      int avail;
      int v;
      int len;
      DECODE_HEAD;

      READ_BUF(sizeof(stateid_opaque_t) + 20);
      READ32(write->wr_stateid.si_generation);
      COPYMEM(&write->wr_stateid.si_opaque, sizeof(stateid_opaque_t));
      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) {
            printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__); 
            goto xdr_error;
      }
      write->wr_vec[0].iov_base = p;
      write->wr_vec[0].iov_len = avail;
      v = 0;
      len = write->wr_buflen;
      while (len > write->wr_vec[v].iov_len) {
            len -= write->wr_vec[v].iov_len;
            v++;
            write->wr_vec[v].iov_base = page_address(argp->pagelist[0]);
            argp->pagelist++;
            if (argp->pagelen >= PAGE_SIZE) {
                  write->wr_vec[v].iov_len = PAGE_SIZE;
                  argp->pagelen -= PAGE_SIZE;
            } else {
                  write->wr_vec[v].iov_len = argp->pagelen;
                  argp->pagelen -= len;
            }
      }
      argp->end = (u32*) (write->wr_vec[v].iov_base + write->wr_vec[v].iov_len);
      argp->p = (u32*)  (write->wr_vec[v].iov_base + (XDR_QUADLEN(len) << 2));
      write->wr_vec[v].iov_len = len;
      write->wr_vlen = v+1;

      DECODE_TAIL;
}

static int
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);

      DECODE_TAIL;
}

static int
nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
{
      DECODE_HEAD;
      struct nfsd4_op *op;
      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;
                  printk(KERN_INFO "nfsd: couldn't allocate room for COMPOUND\n");
                  goto xdr_error;
            }
      }

      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 = p + (argp->pagelen>>2);
                        argp->pagelen = 0;
                  } else {
                        argp->end = p + (PAGE_SIZE>>2);
                        argp->pagelen -= PAGE_SIZE;
                  }
            }
            op->opnum = ntohl(*argp->p++);

            switch (op->opnum) {
            case 2: /* Reserved operation */
                  op->opnum = OP_ILLEGAL;
                  if (argp->minorversion == 0)
                        op->status = nfserr_op_illegal;
                  else
                        op->status = nfserr_minor_vers_mismatch;
                  break;
            case OP_ACCESS:
                  op->status = nfsd4_decode_access(argp, &op->u.access);
                  break;
            case OP_CLOSE:
                  op->status = nfsd4_decode_close(argp, &op->u.close);
                  break;
            case OP_COMMIT:
                  op->status = nfsd4_decode_commit(argp, &op->u.commit);
                  break;
            case OP_CREATE:
                  op->status = nfsd4_decode_create(argp, &op->u.create);
                  break;
            case OP_DELEGRETURN:
                  op->status = nfsd4_decode_delegreturn(argp, &op->u.delegreturn);
                  break;
            case OP_GETATTR:
                  op->status = nfsd4_decode_getattr(argp, &op->u.getattr);
                  break;
            case OP_GETFH:
                  op->status = nfs_ok;
                  break;
            case OP_LINK:
                  op->status = nfsd4_decode_link(argp, &op->u.link);
                  break;
            case OP_LOCK:
                  op->status = nfsd4_decode_lock(argp, &op->u.lock);
                  break;
            case OP_LOCKT:
                  op->status = nfsd4_decode_lockt(argp, &op->u.lockt);
                  break;
            case OP_LOCKU:
                  op->status = nfsd4_decode_locku(argp, &op->u.locku);
                  break;
            case OP_LOOKUP:
                  op->status = nfsd4_decode_lookup(argp, &op->u.lookup);
                  break;
            case OP_LOOKUPP:
                  op->status = nfs_ok;
                  break;
            case OP_NVERIFY:
                  op->status = nfsd4_decode_verify(argp, &op->u.nverify);
                  break;
            case OP_OPEN:
                  op->status = nfsd4_decode_open(argp, &op->u.open);
                  break;
            case OP_OPEN_CONFIRM:
                  op->status = nfsd4_decode_open_confirm(argp, &op->u.open_confirm);
                  break;
            case OP_OPEN_DOWNGRADE:
                  op->status = nfsd4_decode_open_downgrade(argp, &op->u.open_downgrade);
                  break;
            case OP_PUTFH:
                  op->status = nfsd4_decode_putfh(argp, &op->u.putfh);
                  break;
            case OP_PUTROOTFH:
                  op->status = nfs_ok;
                  break;
            case OP_READ:
                  op->status = nfsd4_decode_read(argp, &op->u.read);
                  break;
            case OP_READDIR:
                  op->status = nfsd4_decode_readdir(argp, &op->u.readdir);
                  break;
            case OP_READLINK:
                  op->status = nfs_ok;
                  break;
            case OP_REMOVE:
                  op->status = nfsd4_decode_remove(argp, &op->u.remove);
                  break;
            case OP_RENAME:
                  op->status = nfsd4_decode_rename(argp, &op->u.rename);
                  break;
            case OP_RESTOREFH:
                  op->status = nfs_ok;
                  break;
            case OP_RENEW:
                  op->status = nfsd4_decode_renew(argp, &op->u.renew);
                  break;
            case OP_SAVEFH:
                  op->status = nfs_ok;
                  break;
            case OP_SETATTR:
                  op->status = nfsd4_decode_setattr(argp, &op->u.setattr);
                  break;
            case OP_SETCLIENTID:
                  op->status = nfsd4_decode_setclientid(argp, &op->u.setclientid);
                  break;
            case OP_SETCLIENTID_CONFIRM:
                  op->status = nfsd4_decode_setclientid_confirm(argp, &op->u.setclientid_confirm);
                  break;
            case OP_VERIFY:
                  op->status = nfsd4_decode_verify(argp, &op->u.verify);
                  break;
            case OP_WRITE:
                  op->status = nfsd4_decode_write(argp, &op->u.write);
                  break;
            case OP_RELEASE_LOCKOWNER:
                  op->status = nfsd4_decode_release_lockowner(argp, &op->u.release_lockowner);
                  break;
            default:
                  op->opnum = OP_ILLEGAL;
                  op->status = nfserr_op_illegal;
                  break;
            }

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

      DECODE_TAIL;
}
/*
 * END OF "GENERIC" DECODE ROUTINES.
 */

/*
 * START OF "GENERIC" ENCODE ROUTINES.
 *   These may look a little ugly since they are imported from a "generic"
 * set of XDR encode/decode routines which are intended to be shared by
 * all of our NFSv4 implementations (OpenBSD, MacOS X...).
 *
 * If the pain of reading these is too great, it should be a straightforward
 * task to translate them into Linux-specific versions which are more
 * consistent with the style used in NFSv2/v3...
 */
#define ENCODE_HEAD              u32 *p

#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 {                       \
      *(p + XDR_QUADLEN(nbytes) -1) = 0;                      \
      memcpy(p, ptr, nbytes);                         \
      p += XDR_QUADLEN(nbytes);                       \
} while (0)
#define WRITECINFO(c)         do {                    \
      *p++ = htonl(c.atomic);                         \
      *p++ = htonl(c.before_ctime_sec);                     \
      *p++ = htonl(c.before_ctime_nsec);                    \
      *p++ = htonl(c.after_ctime_sec);                      \
      *p++ = htonl(c.after_ctime_nsec);                     \
} while (0)

#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                          \
      u32 *p;                                         \
      u32 *save;                                \
                                                \
      save = resp->p;

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

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


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

static int
nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
                  u32 **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 int
nfsd4_encode_user(struct svc_rqst *rqstp, uid_t uid, u32 **p, int *buflen)
{
      return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, uid, 0, p, buflen);
}

static inline int
nfsd4_encode_group(struct svc_rqst *rqstp, uid_t gid, u32 **p, int *buflen)
{
      return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, gid, 1, p, buflen);
}

static inline int
nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
            u32 **p, int *buflen)
{
      return nfsd4_encode_name(rqstp, whotype, id, group, p, buflen);
}


/*
 * 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.
 */
int
nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
            struct dentry *dentry, u32 *buffer, int *countp, u32 *bmval,
            struct svc_rqst *rqstp)
{
      u32 bmval0 = bmval[0];
      u32 bmval1 = bmval[1];
      struct kstat stat;
      struct svc_fh tempfh;
      struct kstatfs statfs;
      int buflen = *countp << 2;
      u32 *attrlenp;
      u32 dummy;
      u64 dummy64;
      u32 *p = buffer;
      int status;
      int aclsupport = 0;
      struct nfs4_acl *acl = NULL;

      BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
      BUG_ON(bmval0 & ~NFSD_SUPPORTED_ATTRS_WORD0);
      BUG_ON(bmval1 & ~NFSD_SUPPORTED_ATTRS_WORD1);

      status = vfs_getattr(exp->ex_mnt, dentry, &stat);
      if (status)
            goto out_nfserr;
      if ((bmval0 & (FATTR4_WORD0_FILES_FREE | FATTR4_WORD0_FILES_TOTAL)) ||
          (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
                   FATTR4_WORD1_SPACE_TOTAL))) {
            status = vfs_statfs(dentry, &statfs);
            if (status)
                  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)) {
            status = nfsd4_get_nfs4_acl(rqstp, dentry, &acl);
            aclsupport = (status == 0);
            if (bmval0 & FATTR4_WORD0_ACL) {
                  if (status == -EOPNOTSUPP)
                        bmval0 &= ~FATTR4_WORD0_ACL;
                  else if (status == -EINVAL) {
                        status = nfserr_attrnotsupp;
                        goto out;
                  } else if (status != 0)
                        goto out_nfserr;
            }
      }
      if ((buflen -= 16) < 0)
            goto out_resource;

      WRITE32(2);
      WRITE32(bmval0);
      WRITE32(bmval1);
      attrlenp = p++;                /* to be backfilled later */

      if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
            if ((buflen -= 12) < 0)
                  goto out_resource;
            WRITE32(2);
            WRITE32(aclsupport ?
                  NFSD_SUPPORTED_ATTRS_WORD0 :
                  NFSD_SUPPORTED_ATTRS_WORD0 & ~FATTR4_WORD0_ACL);
            WRITE32(NFSD_SUPPORTED_ATTRS_WORD1);
      }
      if (bmval0 & FATTR4_WORD0_TYPE) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            dummy = nfs4_ftypes[(stat.mode & S_IFMT) >> 12];
            if (dummy == NF4BAD)
                  goto out_serverfault;
            WRITE32(dummy);
      }
      if (bmval0 & FATTR4_WORD0_FH_EXPIRE_TYPE) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
                  WRITE32(NFS4_FH_PERSISTENT);
            else
                  WRITE32(NFS4_FH_PERSISTENT|NFS4_FH_VOL_RENAME);
      }
      if (bmval0 & FATTR4_WORD0_CHANGE) {
            /*
             * Note: This _must_ be consistent with the scheme for writing
             * change_info, so any changes made here must be reflected there
             * as well.  (See xdr4.h:set_change_info() and the WRITECINFO()
             * macro above.)
             */
            if ((buflen -= 8) < 0)
                  goto out_resource;
            WRITE32(stat.ctime.tv_sec);
            WRITE32(stat.ctime.tv_nsec);
      }
      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 (is_fsid(fhp, rqstp->rq_reffh)) {
                  WRITE64((u64)exp->ex_fsid);
                  WRITE64((u64)0);
            } else {
                  WRITE32(0);
                  WRITE32(MAJOR(stat.dev));
                  WRITE32(0);
                  WRITE32(MINOR(stat.dev));
            }
      }
      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(NFSD_LEASE_TIME);
      }
      if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(0);
      }
      if (bmval0 & FATTR4_WORD0_ACL) {
            struct nfs4_ace *ace;
            struct list_head *h;

            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);

            list_for_each(h, &acl->ace_head) {
                  ace = list_entry(h, struct nfs4_ace, l_ace);

                  if ((buflen -= 4*3) < 0)
                        goto out_resource;
                  WRITE32(ace->type);
                  WRITE32(ace->flag);
                  WRITE32(ace->access_mask & NFS4_ACE_MASK_ALL);
                  status = nfsd4_encode_aclname(rqstp, ace->whotype,
                        ace->who, ace->flag & NFS4_ACE_IDENTIFIER_GROUP,
                        &p, &buflen);
                  if (status == nfserr_resource)
                        goto out_resource;
                  if (status)
                        goto out;
            }
      }
out_acl:
      if (bmval0 & FATTR4_WORD0_ACLSUPPORT) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(aclsupport ?
                  ACL4_SUPPORT_ALLOW_ACL|ACL4_SUPPORT_DENY_ACL : 0);
      }
      if (bmval0 & FATTR4_WORD0_CANSETTIME) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(1);
      }
      if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(1);
      }
      if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(1);
      }
      if (bmval0 & FATTR4_WORD0_CHOWN_RESTRICTED) {
            if ((buflen -= 4) < 0)
                  goto out_resource;
            WRITE32(1);
      }
      if (bmval0 & FATTR4_WORD0_FILEHANDLE) {
            buflen -= (XDR_QUADLEN(fhp->fh_handle.fh_size) << 2) + 4;
            if (buflen < 0)
                  goto out_resource;
            WRITE32(fhp->fh_handle.fh_size);
            WRITEMEM(&fhp->fh_handle.fh_base, fhp->fh_handle.fh_size);
      }
      if (bmval0 & FATTR4_WORD0_FILEID) {
            if ((buflen -= 8) < 0)
                  goto out_resource;
            WRITE64((u64) 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_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(~(u32) 0);
      }
      if (bmval0 & FATTR4_WORD0_MAXREAD) {
            if ((buflen -= 8) < 0)
                  goto out_resource;
            WRITE64((u64) NFSSVC_MAXBLKSIZE);
      }
      if (bmval0 & FATTR4_WORD0_MAXWRITE) {
            if ((buflen -= 8) < 0)
                  goto out_resource;
            WRITE64((u64) NFSSVC_MAXBLKSIZE);
      }
      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) {
            struct dentry *mnt_pnt, *mnt_root;

            if ((buflen -= 8) < 0)
                  goto out_resource;
            mnt_root = exp->ex_mnt->mnt_root;
            if (mnt_root->d_inode == dentry->d_inode) {
                  mnt_pnt = exp->ex_mnt->mnt_mountpoint;
                  WRITE64((u64) mnt_pnt->d_inode->i_ino);
            } else
                  WRITE64((u64) stat.ino);
      }
      *attrlenp = htonl((char *)p - (char *)attrlenp - 4);
      *countp = p - buffer;
      status = nfs_ok;

out:
      nfs4_acl_free(acl);
      if (fhp == &tempfh)
            fh_put(&tempfh);
      return status;
out_nfserr:
      status = nfserrno(status);
      goto out;
out_resource:
      *countp = 0;
      status = nfserr_resource;
      goto out;
out_serverfault:
      status = nfserr_serverfault;
      goto out;
}

static int
nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
            const char *name, int namlen, u32 *p, int *buflen)
{
      struct svc_export *exp = cd->rd_fhp->fh_export;
      struct dentry *dentry;
      int nfserr;

      dentry = lookup_one_len(name, cd->rd_fhp->fh_dentry, namlen);
      if (IS_ERR(dentry))
            return nfserrno(PTR_ERR(dentry));

      exp_get(exp);
      if (d_mountpoint(dentry)) {
            if (nfsd_cross_mnt(cd->rd_rqstp, &dentry, &exp)) {
            /*
             * -EAGAIN is the only error returned from
             * nfsd_cross_mnt() and it indicates that an
             * up-call has  been initiated to fill in the export
             * options on exp.  When the answer comes back,
             * this call will be retried.
             */
                  nfserr = nfserr_dropit;
                  goto out_put;
            }

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

static u32 *
nfsd4_encode_rdattr_error(u32 *p, int buflen, int nfserr)
{
      u32 *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(struct readdir_cd *ccd, const char *name, int namlen,
                loff_t offset, ino_t ino, unsigned int d_type)
{
      struct nfsd4_readdir *cd = container_of(ccd, struct nfsd4_readdir, common);
      int buflen;
      u32 *p = cd->buffer;
      int 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 */
      cd->offset = p;                             /* remember pointer */
      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_dropit:
            goto fail;
      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->common.err = nfs_ok;
      return 0;
fail:
      cd->common.err = nfserr;
      return -EINVAL;
}

static void
nfsd4_encode_access(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_access *access)
{
      ENCODE_HEAD;

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

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

      if (!nfserr) {
            RESERVE_SPACE(sizeof(stateid_t));
            WRITE32(close->cl_stateid.si_generation);
            WRITEMEM(&close->cl_stateid.si_opaque, sizeof(stateid_opaque_t));
            ADJUST_ARGS();
      }
      ENCODE_SEQID_OP_TAIL(close->cl_stateowner);
}


static void
nfsd4_encode_commit(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_commit *commit)
{
      ENCODE_HEAD;

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

static void
nfsd4_encode_create(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_create *create)
{
      ENCODE_HEAD;

      if (!nfserr) {
            RESERVE_SPACE(32);
            WRITECINFO(create->cr_cinfo);
            WRITE32(2);
            WRITE32(create->cr_bmval[0]);
            WRITE32(create->cr_bmval[1]);
            ADJUST_ARGS();
      }
}

static int
nfsd4_encode_getattr(struct nfsd4_compoundres *resp, int 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);

      if (!nfserr)
            resp->p += buflen;
      return nfserr;
}

static void
nfsd4_encode_getfh(struct nfsd4_compoundres *resp, int nfserr, struct svc_fh *fhp)
{
      unsigned int len;
      ENCODE_HEAD;

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

/*
* 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)
{
      ENCODE_HEAD;

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

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

      if (!nfserr) {
            RESERVE_SPACE(4 + sizeof(stateid_t));
            WRITE32(lock->lk_resp_stateid.si_generation);
            WRITEMEM(&lock->lk_resp_stateid.si_opaque, sizeof(stateid_opaque_t));
            ADJUST_ARGS();
      } else if (nfserr == nfserr_denied)
            nfsd4_encode_lock_denied(resp, &lock->lk_denied);

      ENCODE_SEQID_OP_TAIL(lock->lk_replay_owner);
}

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

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

      if (!nfserr) {
            RESERVE_SPACE(sizeof(stateid_t));
            WRITE32(locku->lu_stateid.si_generation);
            WRITEMEM(&locku->lu_stateid.si_opaque, sizeof(stateid_opaque_t));
            ADJUST_ARGS();
      }
                                
      ENCODE_SEQID_OP_TAIL(locku->lu_stateowner);
}


static void
nfsd4_encode_link(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_link *link)
{
      ENCODE_HEAD;

      if (!nfserr) {
            RESERVE_SPACE(20);
            WRITECINFO(link->li_cinfo);
            ADJUST_ARGS();
      }
}


static void
nfsd4_encode_open(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_open *open)
{
      ENCODE_SEQID_OP_HEAD;

      if (nfserr)
            goto out;

      RESERVE_SPACE(36 + sizeof(stateid_t));
      WRITE32(open->op_stateid.si_generation);
      WRITEMEM(&open->op_stateid.si_opaque, sizeof(stateid_opaque_t));
      WRITECINFO(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:
            RESERVE_SPACE(20 + sizeof(stateid_t));
            WRITEMEM(&open->op_delegate_stateid, sizeof(stateid_t));
            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:
            RESERVE_SPACE(32 + sizeof(stateid_t));
            WRITEMEM(&open->op_delegate_stateid, sizeof(stateid_t));
            WRITE32(0);

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

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

static void
nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_open_confirm *oc)
{
      ENCODE_SEQID_OP_HEAD;
                                
      if (!nfserr) {
            RESERVE_SPACE(sizeof(stateid_t));
            WRITE32(oc->oc_resp_stateid.si_generation);
            WRITEMEM(&oc->oc_resp_stateid.si_opaque, sizeof(stateid_opaque_t));
            ADJUST_ARGS();
      }

      ENCODE_SEQID_OP_TAIL(oc->oc_stateowner);
}

static void
nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_open_downgrade *od)
{
      ENCODE_SEQID_OP_HEAD;
                                
      if (!nfserr) {
            RESERVE_SPACE(sizeof(stateid_t));
            WRITE32(od->od_stateid.si_generation);
            WRITEMEM(&od->od_stateid.si_opaque, sizeof(stateid_opaque_t));
            ADJUST_ARGS();
      }

      ENCODE_SEQID_OP_TAIL(od->od_stateowner);
}

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

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

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

      maxcount = NFSSVC_MAXBLKSIZE;
      if (maxcount > read->rd_length)
            maxcount = read->rd_length;

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

      nfserr = nfsd_read(read->rd_rqstp, read->rd_fhp, read->rd_filp,
                  read->rd_offset, read->rd_iov, read->rd_vlen,
                  &maxcount);

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

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

      /* Use rest of head for padding and remaining ops: */
      resp->rqstp->rq_restailpage = 0;
      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 int
nfsd4_encode_readlink(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_readlink *readlink)
{
      int maxcount;
      char *page;
      ENCODE_HEAD;

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

      svc_take_page(resp->rqstp);
      page = page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);

      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->rqstp->rq_restailpage = 0;
      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 int
nfsd4_encode_readdir(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_readdir *readdir)
{
      int maxcount;
      loff_t offset;
      u32 *page, *savep, *tailbase;
      ENCODE_HEAD;

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

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

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

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

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

      svc_take_page(resp->rqstp);
      page = page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);
      readdir->common.err = 0;
      readdir->buflen = maxcount;
      readdir->buffer = page;
      readdir->offset = NULL;

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

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

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

      /* Use rest of head for padding and remaining ops: */
      resp->rqstp->rq_restailpage = 0;
      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 void
nfsd4_encode_remove(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_remove *remove)
{
      ENCODE_HEAD;

      if (!nfserr) {
            RESERVE_SPACE(20);
            WRITECINFO(remove->rm_cinfo);
            ADJUST_ARGS();
      }
}

static void
nfsd4_encode_rename(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_rename *rename)
{
      ENCODE_HEAD;

      if (!nfserr) {
            RESERVE_SPACE(40);
            WRITECINFO(rename->rn_sinfo);
            WRITECINFO(rename->rn_tinfo);
            ADJUST_ARGS();
      }
}

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

      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();
}

static void
nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_setclientid *scd)
{
      ENCODE_HEAD;

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

static void
nfsd4_encode_write(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_write *write)
{
      ENCODE_HEAD;

      if (!nfserr) {
            RESERVE_SPACE(16);
            WRITE32(write->wr_bytes_written);
            WRITE32(write->wr_how_written);
            WRITEMEM(write->wr_verifier.data, 8);
            ADJUST_ARGS();
      }
}

void
nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
      u32 *statp;
      ENCODE_HEAD;

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

      switch (op->opnum) {
      case OP_ACCESS:
            nfsd4_encode_access(resp, op->status, &op->u.access);
            break;
      case OP_CLOSE:
            nfsd4_encode_close(resp, op->status, &op->u.close);
            break;
      case OP_COMMIT:
            nfsd4_encode_commit(resp, op->status, &op->u.commit);
            break;
      case OP_CREATE:
            nfsd4_encode_create(resp, op->status, &op->u.create);
            break;
      case OP_DELEGRETURN:
            break;
      case OP_GETATTR:
            op->status = nfsd4_encode_getattr(resp, op->status, &op->u.getattr);
            break;
      case OP_GETFH:
            nfsd4_encode_getfh(resp, op->status, op->u.getfh);
            break;
      case OP_LINK:
            nfsd4_encode_link(resp, op->status, &op->u.link);
            break;
      case OP_LOCK:
            nfsd4_encode_lock(resp, op->status, &op->u.lock);
            break;
      case OP_LOCKT:
            nfsd4_encode_lockt(resp, op->status, &op->u.lockt);
            break;
      case OP_LOCKU:
            nfsd4_encode_locku(resp, op->status, &op->u.locku);
            break;
      case OP_LOOKUP:
            break;
      case OP_LOOKUPP:
            break;
      case OP_NVERIFY:
            break;
      case OP_OPEN:
            nfsd4_encode_open(resp, op->status, &op->u.open);
            break;
      case OP_OPEN_CONFIRM:
            nfsd4_encode_open_confirm(resp, op->status, &op->u.open_confirm);
            break;
      case OP_OPEN_DOWNGRADE:
            nfsd4_encode_open_downgrade(resp, op->status, &op->u.open_downgrade);
            break;
      case OP_PUTFH:
            break;
      case OP_PUTROOTFH:
            break;
      case OP_READ:
            op->status = nfsd4_encode_read(resp, op->status, &op->u.read);
            break;
      case OP_READDIR:
            op->status = nfsd4_encode_readdir(resp, op->status, &op->u.readdir);
            break;
      case OP_READLINK:
            op->status = nfsd4_encode_readlink(resp, op->status, &op->u.readlink);
            break;
      case OP_REMOVE:
            nfsd4_encode_remove(resp, op->status, &op->u.remove);
            break;
      case OP_RENAME:
            nfsd4_encode_rename(resp, op->status, &op->u.rename);
            break;
      case OP_RENEW:
            break;
      case OP_RESTOREFH:
            break;
      case OP_SAVEFH:
            break;
      case OP_SETATTR:
            nfsd4_encode_setattr(resp, op->status, &op->u.setattr);
            break;
      case OP_SETCLIENTID:
            nfsd4_encode_setclientid(resp, op->status, &op->u.setclientid);
            break;
      case OP_SETCLIENTID_CONFIRM:
            break;
      case OP_VERIFY:
            break;
      case OP_WRITE:
            nfsd4_encode_write(resp, op->status, &op->u.write);
            break;
      case OP_RELEASE_LOCKOWNER:
            break;
      default:
            break;
      }

      /*
       * 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)
{
      ENCODE_HEAD;
      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();
}

/*
 * END OF "GENERIC" ENCODE ROUTINES.
 */

int
nfs4svc_encode_voidres(struct svc_rqst *rqstp, u32 *p, void *dummy)
{
        return xdr_ressize_check(rqstp, p);
}

void nfsd4_release_compoundargs(struct nfsd4_compoundargs *args)
{
      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);
      }
}

int
nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, u32 *p, struct nfsd4_compoundargs *args)
{
      int status;

      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;

      status = nfsd4_decode_compound(args);
      if (status) {
            nfsd4_release_compoundargs(args);
      }
      return !status;
}

int
nfs4svc_encode_compoundres(struct svc_rqst *rqstp, u32 *p, struct nfsd4_compoundres *resp)
{
      /*
       * All that remains is to write the tag and operation count...
       */
      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);
      return 1;
}

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

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