/*

   * XDR support for nfsd/protocol version 3.
   *
   * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   *
   * 2003-08-09 Jamie Lokier: Use htonl() for nanoseconds, not htons()!
   */

  #include <linux/namei.h>

  #include "xdr3.h"

  #include "auth.h"

  
  #define NFSDDBG_FACILITY		NFSDDBG_XDR

  
  /*
   * Mapping of S_IF* types to NFS file types
   */
  static u32	nfs3_ftypes[] = {
  	NF3NON,  NF3FIFO, NF3CHR, NF3BAD,
  	NF3DIR,  NF3BAD,  NF3BLK, NF3BAD,
  	NF3REG,  NF3BAD,  NF3LNK, NF3BAD,
  	NF3SOCK, NF3BAD,  NF3LNK, NF3BAD,
  };
  
  /*
   * XDR functions for basic NFS types
   */

  static __be32 *

  encode_time3(__be32 *p, struct timespec *time)

  {
  	*p++ = htonl((u32) time->tv_sec); *p++ = htonl(time->tv_nsec);
  	return p;
  }

  static __be32 *

  decode_time3(__be32 *p, struct timespec *time)

  {
  	time->tv_sec = ntohl(*p++);
  	time->tv_nsec = ntohl(*p++);
  	return p;
  }

  static __be32 *

  decode_fh(__be32 *p, struct svc_fh *fhp)

  {
  	unsigned int size;
  	fh_init(fhp, NFS3_FHSIZE);
  	size = ntohl(*p++);
  	if (size > NFS3_FHSIZE)
  		return NULL;
  
  	memcpy(&fhp->fh_handle.fh_base, p, size);
  	fhp->fh_handle.fh_size = size;
  	return p + XDR_QUADLEN(size);
  }

  /* Helper function for NFSv3 ACL code */

  __be32 *nfs3svc_decode_fh(__be32 *p, struct svc_fh *fhp)

  {
  	return decode_fh(p, fhp);
  }

  static __be32 *

  encode_fh(__be32 *p, struct svc_fh *fhp)

  {
  	unsigned int size = fhp->fh_handle.fh_size;
  	*p++ = htonl(size);
  	if (size) p[XDR_QUADLEN(size)-1]=0;
  	memcpy(p, &fhp->fh_handle.fh_base, size);
  	return p + XDR_QUADLEN(size);
  }
  
  /*
   * Decode a file name and make sure that the path contains
   * no slashes or null bytes.
   */

  static __be32 *

  decode_filename(__be32 *p, char **namp, unsigned int *lenp)

  {
  	char		*name;

  	unsigned int	i;

  
  	if ((p = xdr_decode_string_inplace(p, namp, lenp, NFS3_MAXNAMLEN)) != NULL) {
  		for (i = 0, name = *namp; i < *lenp; i++, name++) {
  			if (*name == '\0' || *name == '/')
  				return NULL;
  		}
  	}
  
  	return p;
  }

  static __be32 *

  decode_sattr3(__be32 *p, struct iattr *iap)

  {
  	u32	tmp;
  
  	iap->ia_valid = 0;
  
  	if (*p++) {
  		iap->ia_valid |= ATTR_MODE;
  		iap->ia_mode = ntohl(*p++);
  	}
  	if (*p++) {
  		iap->ia_valid |= ATTR_UID;
  		iap->ia_uid = ntohl(*p++);
  	}
  	if (*p++) {
  		iap->ia_valid |= ATTR_GID;
  		iap->ia_gid = ntohl(*p++);
  	}
  	if (*p++) {
  		u64	newsize;
  
  		iap->ia_valid |= ATTR_SIZE;
  		p = xdr_decode_hyper(p, &newsize);
  		if (newsize <= NFS_OFFSET_MAX)
  			iap->ia_size = newsize;
  		else
  			iap->ia_size = NFS_OFFSET_MAX;
  	}
  	if ((tmp = ntohl(*p++)) == 1) {	/* set to server time */
  		iap->ia_valid |= ATTR_ATIME;
  	} else if (tmp == 2) {		/* set to client time */
  		iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
  		iap->ia_atime.tv_sec = ntohl(*p++);
  		iap->ia_atime.tv_nsec = ntohl(*p++);
  	}
  	if ((tmp = ntohl(*p++)) == 1) {	/* set to server time */
  		iap->ia_valid |= ATTR_MTIME;
  	} else if (tmp == 2) {		/* set to client time */
  		iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
  		iap->ia_mtime.tv_sec = ntohl(*p++);
  		iap->ia_mtime.tv_nsec = ntohl(*p++);
  	}
  	return p;
  }

  static __be32 *encode_fsid(__be32 *p, struct svc_fh *fhp)
  {
  	u64 f;
  	switch(fsid_source(fhp)) {
  	default:
  	case FSIDSOURCE_DEV:
  		p = xdr_encode_hyper(p, (u64)huge_encode_dev
  				     (fhp->fh_dentry->d_inode->i_sb->s_dev));
  		break;
  	case FSIDSOURCE_FSID:
  		p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
  		break;
  	case FSIDSOURCE_UUID:
  		f = ((u64*)fhp->fh_export->ex_uuid)[0];
  		f ^= ((u64*)fhp->fh_export->ex_uuid)[1];
  		p = xdr_encode_hyper(p, f);
  		break;
  	}
  	return p;
  }

  static __be32 *

  encode_fattr3(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,

  	      struct kstat *stat)

  {

  	*p++ = htonl(nfs3_ftypes[(stat->mode & S_IFMT) >> 12]);
  	*p++ = htonl((u32) stat->mode);
  	*p++ = htonl((u32) stat->nlink);
  	*p++ = htonl((u32) nfsd_ruid(rqstp, stat->uid));
  	*p++ = htonl((u32) nfsd_rgid(rqstp, stat->gid));
  	if (S_ISLNK(stat->mode) && stat->size > NFS3_MAXPATHLEN) {

  		p = xdr_encode_hyper(p, (u64) NFS3_MAXPATHLEN);
  	} else {

  		p = xdr_encode_hyper(p, (u64) stat->size);

  	}

  	p = xdr_encode_hyper(p, ((u64)stat->blocks) << 9);
  	*p++ = htonl((u32) MAJOR(stat->rdev));
  	*p++ = htonl((u32) MINOR(stat->rdev));

  	p = encode_fsid(p, fhp);

  	p = xdr_encode_hyper(p, stat->ino);

  	p = encode_time3(p, &stat->atime);

  	p = encode_time3(p, &stat->mtime);

  	p = encode_time3(p, &stat->ctime);

  
  	return p;
  }

  static __be32 *

  encode_saved_post_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)

  {

  	/* Attributes to follow */
  	*p++ = xdr_one;

  	return encode_fattr3(rqstp, p, fhp, &fhp->fh_post_attr);

  }
  
  /*
   * Encode post-operation attributes.
   * The inode may be NULL if the call failed because of a stale file
   * handle. In this case, no attributes are returned.
   */

  static __be32 *
  encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)

  {
  	struct dentry *dentry = fhp->fh_dentry;

  	if (dentry && dentry->d_inode) {

  	        int err;
  		struct kstat stat;

  		err = vfs_getattr(fhp->fh_export->ex_path.mnt, dentry, &stat);

  		if (!err) {
  			*p++ = xdr_one;		/* attributes follow */

  			lease_get_mtime(dentry->d_inode, &stat.mtime);

  			return encode_fattr3(rqstp, p, fhp, &stat);
  		}

  	}
  	*p++ = xdr_zero;
  	return p;
  }

  /* Helper for NFSv3 ACLs */

  __be32 *
  nfs3svc_encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)

  {
  	return encode_post_op_attr(rqstp, p, fhp);
  }

  /*
   * Enocde weak cache consistency data
   */

  static __be32 *
  encode_wcc_data(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)

  {
  	struct dentry	*dentry = fhp->fh_dentry;
  
  	if (dentry && dentry->d_inode && fhp->fh_post_saved) {
  		if (fhp->fh_pre_saved) {
  			*p++ = xdr_one;
  			p = xdr_encode_hyper(p, (u64) fhp->fh_pre_size);
  			p = encode_time3(p, &fhp->fh_pre_mtime);
  			p = encode_time3(p, &fhp->fh_pre_ctime);
  		} else {
  			*p++ = xdr_zero;
  		}
  		return encode_saved_post_attr(rqstp, p, fhp);
  	}
  	/* no pre- or post-attrs */
  	*p++ = xdr_zero;
  	return encode_post_op_attr(rqstp, p, fhp);
  }

  /*
   * Fill in the post_op attr for the wcc data
   */
  void fill_post_wcc(struct svc_fh *fhp)
  {
  	int err;
  
  	if (fhp->fh_post_saved)
  		printk("nfsd: inode locked twice during operation.
  ");

  	err = vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry,

  			&fhp->fh_post_attr);

  	fhp->fh_post_change = fhp->fh_dentry->d_inode->i_version;

  	if (err) {

  		fhp->fh_post_saved = 0;

  		/* Grab the ctime anyway - set_change_info might use it */
  		fhp->fh_post_attr.ctime = fhp->fh_dentry->d_inode->i_ctime;
  	} else

  		fhp->fh_post_saved = 1;
  }

  
  /*
   * XDR decode functions
   */
  int

  nfs3svc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p, struct nfsd_fhandle *args)

  {
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_sattrargs *args)
  {

  	if (!(p = decode_fh(p, &args->fh)))

  		return 0;

  	p = decode_sattr3(p, &args->attrs);

  
  	if ((args->check_guard = ntohl(*p++)) != 0) { 
  		struct timespec time; 
  		p = decode_time3(p, &time);
  		args->guardtime = time.tv_sec;
  	}
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_diropargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh))
  	 || !(p = decode_filename(p, &args->name, &args->len)))
  		return 0;
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_accessargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_accessargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;
  	args->access = ntohl(*p++);
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_readargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readargs *args)
  {
  	unsigned int len;
  	int v,pn;

  	u32 max_blocksize = svc_max_payload(rqstp);

  	if (!(p = decode_fh(p, &args->fh)))

  		return 0;

  	p = xdr_decode_hyper(p, &args->offset);

  
  	len = args->count = ntohl(*p++);

  	if (len > max_blocksize)
  		len = max_blocksize;

  
  	/* set up the kvec */
  	v=0;
  	while (len > 0) {

  		pn = rqstp->rq_resused++;

  		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_respages[pn]);
  		rqstp->rq_vec[v].iov_len = len < PAGE_SIZE? len : PAGE_SIZE;
  		len -= rqstp->rq_vec[v].iov_len;

  		v++;
  	}
  	args->vlen = v;
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_writeargs *args)
  {

  	unsigned int len, v, hdr, dlen;

  	u32 max_blocksize = svc_max_payload(rqstp);

  	if (!(p = decode_fh(p, &args->fh)))

  		return 0;

  	p = xdr_decode_hyper(p, &args->offset);

  
  	args->count = ntohl(*p++);
  	args->stable = ntohl(*p++);
  	len = args->len = ntohl(*p++);

  	/*
  	 * The count must equal the amount of data passed.
  	 */
  	if (args->count != args->len)
  		return 0;

  	/*
  	 * Check to make sure that we got the right number of
  	 * bytes.

  	 */

  	hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;

  	dlen = rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len
  		- hdr;

  	/*
  	 * Round the length of the data which was specified up to
  	 * the next multiple of XDR units and then compare that
  	 * against the length which was actually received.

  	 * Note that when RPCSEC/GSS (for example) is used, the
  	 * data buffer can be padded so dlen might be larger
  	 * than required.  It must never be smaller.

  	 */

  	if (dlen < XDR_QUADLEN(len)*4)

  		return 0;

  	if (args->count > max_blocksize) {
  		args->count = max_blocksize;
  		len = args->len = max_blocksize;
  	}

  	rqstp->rq_vec[0].iov_base = (void*)p;
  	rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len - hdr;

  	v = 0;

  	while (len > rqstp->rq_vec[v].iov_len) {
  		len -= rqstp->rq_vec[v].iov_len;

  		v++;

  		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);
  		rqstp->rq_vec[v].iov_len = PAGE_SIZE;

  	}

  	rqstp->rq_vec[v].iov_len = len;

  	args->vlen = v + 1;
  	return 1;

  }
  
  int

  nfs3svc_decode_createargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_createargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh))
  	 || !(p = decode_filename(p, &args->name, &args->len)))
  		return 0;
  
  	switch (args->createmode = ntohl(*p++)) {
  	case NFS3_CREATE_UNCHECKED:
  	case NFS3_CREATE_GUARDED:

  		p = decode_sattr3(p, &args->attrs);

  		break;
  	case NFS3_CREATE_EXCLUSIVE:
  		args->verf = p;
  		p += 2;
  		break;
  	default:
  		return 0;
  	}
  
  	return xdr_argsize_check(rqstp, p);
  }
  int

  nfs3svc_decode_mkdirargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_createargs *args)
  {

  	if (!(p = decode_fh(p, &args->fh)) ||
  	    !(p = decode_filename(p, &args->name, &args->len)))

  		return 0;

  	p = decode_sattr3(p, &args->attrs);

  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_symlinkargs *args)
  {

  	unsigned int len, avail;

  	char *old, *new;
  	struct kvec *vec;

  	if (!(p = decode_fh(p, &args->ffh)) ||
  	    !(p = decode_filename(p, &args->fname, &args->flen))

  		)
  		return 0;

  	p = decode_sattr3(p, &args->attrs);

  	/* now decode the pathname, which might be larger than the first page.
  	 * As we have to check for nul's anyway, we copy it into a new page
  	 * This page appears in the rq_res.pages list, but as pages_len is always
  	 * 0, it won't get in the way
  	 */

  	len = ntohl(*p++);
  	if (len == 0 || len > NFS3_MAXPATHLEN || len >= PAGE_SIZE)
  		return 0;

  	args->tname = new =
  		page_address(rqstp->rq_respages[rqstp->rq_resused++]);

  	args->tlen = len;
  	/* first copy and check from the first page */
  	old = (char*)p;
  	vec = &rqstp->rq_arg.head[0];
  	avail = vec->iov_len - (old - (char*)vec->iov_base);
  	while (len && avail && *old) {
  		*new++ = *old++;
  		len--;
  		avail--;
  	}
  	/* now copy next page if there is one */
  	if (len && !avail && rqstp->rq_arg.page_len) {
  		avail = rqstp->rq_arg.page_len;

  		if (avail > PAGE_SIZE)
  			avail = PAGE_SIZE;

  		old = page_address(rqstp->rq_arg.pages[0]);
  	}
  	while (len && avail && *old) {
  		*new++ = *old++;
  		len--;
  		avail--;
  	}
  	*new = '\0';
  	if (len)
  		return 0;
  
  	return 1;
  }
  
  int

  nfs3svc_decode_mknodargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_mknodargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh))
  	 || !(p = decode_filename(p, &args->name, &args->len)))
  		return 0;
  
  	args->ftype = ntohl(*p++);
  
  	if (args->ftype == NF3BLK  || args->ftype == NF3CHR

  	 || args->ftype == NF3SOCK || args->ftype == NF3FIFO)
  		p = decode_sattr3(p, &args->attrs);

  
  	if (args->ftype == NF3BLK || args->ftype == NF3CHR) {
  		args->major = ntohl(*p++);
  		args->minor = ntohl(*p++);
  	}
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_renameargs *args)
  {
  	if (!(p = decode_fh(p, &args->ffh))
  	 || !(p = decode_filename(p, &args->fname, &args->flen))
  	 || !(p = decode_fh(p, &args->tfh))
  	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
  		return 0;
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readlinkargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;

  	args->buffer =
  		page_address(rqstp->rq_respages[rqstp->rq_resused++]);

  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_linkargs *args)
  {
  	if (!(p = decode_fh(p, &args->ffh))
  	 || !(p = decode_fh(p, &args->tfh))
  	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
  		return 0;
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readdirargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;
  	p = xdr_decode_hyper(p, &args->cookie);
  	args->verf   = p; p += 2;
  	args->dircount = ~0;
  	args->count  = ntohl(*p++);
  
  	if (args->count > PAGE_SIZE)
  		args->count = PAGE_SIZE;

  	args->buffer =
  		page_address(rqstp->rq_respages[rqstp->rq_resused++]);

  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_readdirplusargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readdirargs *args)
  {
  	int len, pn;

  	u32 max_blocksize = svc_max_payload(rqstp);

  
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;
  	p = xdr_decode_hyper(p, &args->cookie);
  	args->verf     = p; p += 2;
  	args->dircount = ntohl(*p++);
  	args->count    = ntohl(*p++);

  	len = (args->count > max_blocksize) ? max_blocksize :

  						  args->count;
  	args->count = len;
  
  	while (len > 0) {

  		pn = rqstp->rq_resused++;

  		if (!args->buffer)
  			args->buffer = page_address(rqstp->rq_respages[pn]);
  		len -= PAGE_SIZE;
  	}
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  int

  nfs3svc_decode_commitargs(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_commitargs *args)
  {
  	if (!(p = decode_fh(p, &args->fh)))
  		return 0;
  	p = xdr_decode_hyper(p, &args->offset);
  	args->count = ntohl(*p++);
  
  	return xdr_argsize_check(rqstp, p);
  }
  
  /*
   * XDR encode functions
   */
  /*
   * There must be an encoding function for void results so svc_process
   * will work properly.
   */
  int

  nfs3svc_encode_voidres(struct svc_rqst *rqstp, __be32 *p, void *dummy)

  {
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* GETATTR */
  int

  nfs3svc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_attrstat *resp)
  {

  	if (resp->status == 0) {
  		lease_get_mtime(resp->fh.fh_dentry->d_inode,
  				&resp->stat.mtime);

  		p = encode_fattr3(rqstp, p, &resp->fh, &resp->stat);

  	}

  	return xdr_ressize_check(rqstp, p);
  }
  
  /* SETATTR, REMOVE, RMDIR */
  int

  nfs3svc_encode_wccstat(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_attrstat *resp)
  {
  	p = encode_wcc_data(rqstp, p, &resp->fh);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* LOOKUP */
  int

  nfs3svc_encode_diropres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_diropres *resp)
  {
  	if (resp->status == 0) {
  		p = encode_fh(p, &resp->fh);
  		p = encode_post_op_attr(rqstp, p, &resp->fh);
  	}
  	p = encode_post_op_attr(rqstp, p, &resp->dirfh);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* ACCESS */
  int

  nfs3svc_encode_accessres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_accessres *resp)
  {
  	p = encode_post_op_attr(rqstp, p, &resp->fh);
  	if (resp->status == 0)
  		*p++ = htonl(resp->access);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* READLINK */
  int

  nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readlinkres *resp)
  {
  	p = encode_post_op_attr(rqstp, p, &resp->fh);
  	if (resp->status == 0) {
  		*p++ = htonl(resp->len);
  		xdr_ressize_check(rqstp, p);
  		rqstp->rq_res.page_len = resp->len;
  		if (resp->len & 3) {
  			/* need to pad the tail */

  			rqstp->rq_res.tail[0].iov_base = p;
  			*p = 0;
  			rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
  		}
  		return 1;
  	} else
  		return xdr_ressize_check(rqstp, p);
  }
  
  /* READ */
  int

  nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readres *resp)
  {
  	p = encode_post_op_attr(rqstp, p, &resp->fh);
  	if (resp->status == 0) {
  		*p++ = htonl(resp->count);
  		*p++ = htonl(resp->eof);
  		*p++ = htonl(resp->count);	/* xdr opaque count */
  		xdr_ressize_check(rqstp, p);

  		/* now update rqstp->rq_res to reflect data as well */

  		rqstp->rq_res.page_len = resp->count;
  		if (resp->count & 3) {
  			/* need to pad the tail */

  			rqstp->rq_res.tail[0].iov_base = p;
  			*p = 0;
  			rqstp->rq_res.tail[0].iov_len = 4 - (resp->count & 3);
  		}
  		return 1;
  	} else
  		return xdr_ressize_check(rqstp, p);
  }
  
  /* WRITE */
  int

  nfs3svc_encode_writeres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_writeres *resp)
  {
  	p = encode_wcc_data(rqstp, p, &resp->fh);
  	if (resp->status == 0) {
  		*p++ = htonl(resp->count);
  		*p++ = htonl(resp->committed);
  		*p++ = htonl(nfssvc_boot.tv_sec);
  		*p++ = htonl(nfssvc_boot.tv_usec);
  	}
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* CREATE, MKDIR, SYMLINK, MKNOD */
  int

  nfs3svc_encode_createres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_diropres *resp)
  {
  	if (resp->status == 0) {
  		*p++ = xdr_one;
  		p = encode_fh(p, &resp->fh);
  		p = encode_post_op_attr(rqstp, p, &resp->fh);
  	}
  	p = encode_wcc_data(rqstp, p, &resp->dirfh);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* RENAME */
  int

  nfs3svc_encode_renameres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_renameres *resp)
  {
  	p = encode_wcc_data(rqstp, p, &resp->ffh);
  	p = encode_wcc_data(rqstp, p, &resp->tfh);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* LINK */
  int

  nfs3svc_encode_linkres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_linkres *resp)
  {
  	p = encode_post_op_attr(rqstp, p, &resp->fh);
  	p = encode_wcc_data(rqstp, p, &resp->tfh);
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* READDIR */
  int

  nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_readdirres *resp)
  {
  	p = encode_post_op_attr(rqstp, p, &resp->fh);
  
  	if (resp->status == 0) {
  		/* stupid readdir cookie */
  		memcpy(p, resp->verf, 8); p += 2;
  		xdr_ressize_check(rqstp, p);
  		if (rqstp->rq_res.head[0].iov_len + (2<<2) > PAGE_SIZE)
  			return 1; /*No room for trailer */
  		rqstp->rq_res.page_len = (resp->count) << 2;
  
  		/* add the 'tail' to the end of the 'head' page - page 0. */

  		rqstp->rq_res.tail[0].iov_base = p;
  		*p++ = 0;		/* no more entries */
  		*p++ = htonl(resp->common.err == nfserr_eof);
  		rqstp->rq_res.tail[0].iov_len = 2<<2;
  		return 1;
  	} else
  		return xdr_ressize_check(rqstp, p);
  }

  static __be32 *

  encode_entry_baggage(struct nfsd3_readdirres *cd, __be32 *p, const char *name,

  	     int namlen, u64 ino)

  {
  	*p++ = xdr_one;				 /* mark entry present */
  	p    = xdr_encode_hyper(p, ino);	 /* file id */
  	p    = xdr_encode_array(p, name, namlen);/* name length & name */
  
  	cd->offset = p;				/* remember pointer */
  	p = xdr_encode_hyper(p, NFS_OFFSET_MAX);/* offset of next entry */
  
  	return p;
  }

  static int
  compose_entry_fh(struct nfsd3_readdirres *cd, struct svc_fh *fhp,
  		const char *name, int namlen)
  {
  	struct svc_export	*exp;
  	struct dentry		*dparent, *dchild;
  	int rv = 0;
  
  	dparent = cd->fh.fh_dentry;
  	exp  = cd->fh.fh_export;

  	if (isdotent(name, namlen)) {
  		if (namlen == 2) {
  			dchild = dget_parent(dparent);
  			if (dchild == dparent) {
  				/* filesystem root - cannot return filehandle for ".." */
  				dput(dchild);

  				return -ENOENT;

  			}
  		} else
  			dchild = dget(dparent);
  	} else
  		dchild = lookup_one_len(name, dparent, namlen);
  	if (IS_ERR(dchild))

  		return -ENOENT;
  	rv = -ENOENT;
  	if (d_mountpoint(dchild))
  		goto out;
  	rv = fh_compose(fhp, exp, dchild, &cd->fh);
  	if (rv)
  		goto out;
  	if (!dchild->d_inode)
  		goto out;
  	rv = 0;
  out:

  	dput(dchild);
  	return rv;
  }

  static __be32 *encode_entryplus_baggage(struct nfsd3_readdirres *cd, __be32 *p, const char *name, int namlen)

  {
  	struct svc_fh	fh;
  	int err;

  	fh_init(&fh, NFS3_FHSIZE);

  	err = compose_entry_fh(cd, &fh, name, namlen);
  	if (err) {
  		*p++ = 0;
  		*p++ = 0;

  		goto out;

  	}
  	p = encode_post_op_attr(cd->rqstp, p, &fh);
  	*p++ = xdr_one;			/* yes, a file handle follows */
  	p = encode_fh(p, &fh);

  out:

  	fh_put(&fh);
  	return p;
  }

  /*
   * Encode a directory entry. This one works for both normal readdir
   * and readdirplus.
   * The normal readdir reply requires 2 (fileid) + 1 (stringlen)
   * + string + 2 (cookie) + 1 (next) words, i.e. 6 + strlen.
   * 
   * The readdirplus baggage is 1+21 words for post_op_attr, plus the
   * file handle.
   */
  
  #define NFS3_ENTRY_BAGGAGE	(2 + 1 + 2 + 1)
  #define NFS3_ENTRYPLUS_BAGGAGE	(1 + 21 + 1 + (NFS3_FHSIZE >> 2))
  static int

  encode_entry(struct readdir_cd *ccd, const char *name, int namlen,

  	     loff_t offset, u64 ino, unsigned int d_type, int plus)

  {
  	struct nfsd3_readdirres *cd = container_of(ccd, struct nfsd3_readdirres,
  		       					common);

  	__be32		*p = cd->buffer;

  	caddr_t		curr_page_addr = NULL;
  	int		pn;		/* current page number */
  	int		slen;		/* string (name) length */
  	int		elen;		/* estimated entry length in words */
  	int		num_entry_words = 0;	/* actual number of words */
  
  	if (cd->offset) {
  		u64 offset64 = offset;
  
  		if (unlikely(cd->offset1)) {
  			/* we ended up with offset on a page boundary */
  			*cd->offset = htonl(offset64 >> 32);
  			*cd->offset1 = htonl(offset64 & 0xffffffff);
  			cd->offset1 = NULL;
  		} else {

  			xdr_encode_hyper(cd->offset, offset64);

  		}
  	}
  
  	/*
  	dprintk("encode_entry(%.*s @%ld%s)
  ",
  		namlen, name, (long) offset, plus? " plus" : "");
  	 */
  
  	/* truncate filename if too long */
  	if (namlen > NFS3_MAXNAMLEN)
  		namlen = NFS3_MAXNAMLEN;
  
  	slen = XDR_QUADLEN(namlen);
  	elen = slen + NFS3_ENTRY_BAGGAGE
  		+ (plus? NFS3_ENTRYPLUS_BAGGAGE : 0);
  
  	if (cd->buflen < elen) {
  		cd->common.err = nfserr_toosmall;
  		return -EINVAL;
  	}
  
  	/* determine which page in rq_respages[] we are currently filling */
  	for (pn=1; pn < cd->rqstp->rq_resused; pn++) {
  		curr_page_addr = page_address(cd->rqstp->rq_respages[pn]);
  
  		if (((caddr_t)cd->buffer >= curr_page_addr) &&
  		    ((caddr_t)cd->buffer <  curr_page_addr + PAGE_SIZE))
  			break;
  	}
  
  	if ((caddr_t)(cd->buffer + elen) < (curr_page_addr + PAGE_SIZE)) {
  		/* encode entry in current page */
  
  		p = encode_entry_baggage(cd, p, name, namlen, ino);

  		if (plus)
  			p = encode_entryplus_baggage(cd, p, name, namlen);

  		num_entry_words = p - cd->buffer;
  	} else if (cd->rqstp->rq_respages[pn+1] != NULL) {
  		/* temporarily encode entry into next page, then move back to
  		 * current and next page in rq_respages[] */

  		__be32 *p1, *tmp;

  		int len1, len2;
  
  		/* grab next page for temporary storage of entry */
  		p1 = tmp = page_address(cd->rqstp->rq_respages[pn+1]);
  
  		p1 = encode_entry_baggage(cd, p1, name, namlen, ino);

  		if (plus)

  			p1 = encode_entryplus_baggage(cd, p1, name, namlen);

  
  		/* determine entry word length and lengths to go in pages */
  		num_entry_words = p1 - tmp;
  		len1 = curr_page_addr + PAGE_SIZE - (caddr_t)cd->buffer;
  		if ((num_entry_words << 2) < len1) {
  			/* the actual number of words in the entry is less
  			 * than elen and can still fit in the current page
  			 */
  			memmove(p, tmp, num_entry_words << 2);
  			p += num_entry_words;
  
  			/* update offset */
  			cd->offset = cd->buffer + (cd->offset - tmp);
  		} else {
  			unsigned int offset_r = (cd->offset - tmp) << 2;
  
  			/* update pointer to offset location.
  			 * This is a 64bit quantity, so we need to
  			 * deal with 3 cases:
  			 *  -	entirely in first page
  			 *  -	entirely in second page
  			 *  -	4 bytes in each page
  			 */
  			if (offset_r + 8 <= len1) {
  				cd->offset = p + (cd->offset - tmp);
  			} else if (offset_r >= len1) {
  				cd->offset -= len1 >> 2;
  			} else {
  				/* sitting on the fence */
  				BUG_ON(offset_r != len1 - 4);
  				cd->offset = p + (cd->offset - tmp);
  				cd->offset1 = tmp;
  			}
  
  			len2 = (num_entry_words << 2) - len1;
  
  			/* move from temp page to current and next pages */
  			memmove(p, tmp, len1);
  			memmove(tmp, (caddr_t)tmp+len1, len2);
  
  			p = tmp + (len2 >> 2);
  		}
  	}
  	else {
  		cd->common.err = nfserr_toosmall;
  		return -EINVAL;
  	}
  
  	cd->buflen -= num_entry_words;
  	cd->buffer = p;
  	cd->common.err = nfs_ok;
  	return 0;
  
  }
  
  int

  nfs3svc_encode_entry(void *cd, const char *name,
  		     int namlen, loff_t offset, u64 ino, unsigned int d_type)

  {
  	return encode_entry(cd, name, namlen, offset, ino, d_type, 0);
  }
  
  int

  nfs3svc_encode_entry_plus(void *cd, const char *name,
  			  int namlen, loff_t offset, u64 ino,
  			  unsigned int d_type)

  {
  	return encode_entry(cd, name, namlen, offset, ino, d_type, 1);
  }
  
  /* FSSTAT */
  int

  nfs3svc_encode_fsstatres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_fsstatres *resp)
  {
  	struct kstatfs	*s = &resp->stats;
  	u64		bs = s->f_bsize;
  
  	*p++ = xdr_zero;	/* no post_op_attr */
  
  	if (resp->status == 0) {
  		p = xdr_encode_hyper(p, bs * s->f_blocks);	/* total bytes */
  		p = xdr_encode_hyper(p, bs * s->f_bfree);	/* free bytes */
  		p = xdr_encode_hyper(p, bs * s->f_bavail);	/* user available bytes */
  		p = xdr_encode_hyper(p, s->f_files);	/* total inodes */
  		p = xdr_encode_hyper(p, s->f_ffree);	/* free inodes */
  		p = xdr_encode_hyper(p, s->f_ffree);	/* user available inodes */
  		*p++ = htonl(resp->invarsec);	/* mean unchanged time */
  	}
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* FSINFO */
  int

  nfs3svc_encode_fsinfores(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_fsinfores *resp)
  {
  	*p++ = xdr_zero;	/* no post_op_attr */
  
  	if (resp->status == 0) {
  		*p++ = htonl(resp->f_rtmax);
  		*p++ = htonl(resp->f_rtpref);
  		*p++ = htonl(resp->f_rtmult);
  		*p++ = htonl(resp->f_wtmax);
  		*p++ = htonl(resp->f_wtpref);
  		*p++ = htonl(resp->f_wtmult);
  		*p++ = htonl(resp->f_dtpref);
  		p = xdr_encode_hyper(p, resp->f_maxfilesize);
  		*p++ = xdr_one;
  		*p++ = xdr_zero;
  		*p++ = htonl(resp->f_properties);
  	}
  
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* PATHCONF */
  int

  nfs3svc_encode_pathconfres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_pathconfres *resp)
  {
  	*p++ = xdr_zero;	/* no post_op_attr */
  
  	if (resp->status == 0) {
  		*p++ = htonl(resp->p_link_max);
  		*p++ = htonl(resp->p_name_max);
  		*p++ = htonl(resp->p_no_trunc);
  		*p++ = htonl(resp->p_chown_restricted);
  		*p++ = htonl(resp->p_case_insensitive);
  		*p++ = htonl(resp->p_case_preserving);
  	}
  
  	return xdr_ressize_check(rqstp, p);
  }
  
  /* COMMIT */
  int

  nfs3svc_encode_commitres(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_commitres *resp)
  {
  	p = encode_wcc_data(rqstp, p, &resp->fh);
  	/* Write verifier */
  	if (resp->status == 0) {
  		*p++ = htonl(nfssvc_boot.tv_sec);
  		*p++ = htonl(nfssvc_boot.tv_usec);
  	}
  	return xdr_ressize_check(rqstp, p);
  }
  
  /*
   * XDR release functions
   */
  int

  nfs3svc_release_fhandle(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_attrstat *resp)
  {
  	fh_put(&resp->fh);
  	return 1;
  }
  
  int

  nfs3svc_release_fhandle2(struct svc_rqst *rqstp, __be32 *p,

  					struct nfsd3_fhandle_pair *resp)
  {
  	fh_put(&resp->fh1);
  	fh_put(&resp->fh2);
  	return 1;
  }