/*
   *  fs/nfsd/nfs4proc.c
   *
   *  Server-side procedures for NFSv4.
   *
   *  Copyright (c) 2002 The Regents of the University of Michigan.
   *  All rights reserved.
   *
   *  Kendrick Smith <kmsmith@umich.edu>
   *  Andy Adamson   <andros@umich.edu>
   *
   *  Redistribution and use in source and binary forms, with or without
   *  modification, are permitted provided that the following conditions
   *  are met:
   *
   *  1. Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   *  2. Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   *  3. Neither the name of the University nor the names of its
   *     contributors may be used to endorse or promote products derived
   *     from this software without specific prior written permission.
   *
   *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
   *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
   *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   */
  
  #include <linux/param.h>
  #include <linux/major.h>
  #include <linux/slab.h>

  #include <linux/file.h>

  
  #include <linux/sunrpc/svc.h>
  #include <linux/nfsd/nfsd.h>
  #include <linux/nfsd/cache.h>
  #include <linux/nfs4.h>
  #include <linux/nfsd/state.h>
  #include <linux/nfsd/xdr4.h>
  #include <linux/nfs4_acl.h>

  #include <linux/sunrpc/gss_api.h>

  
  #define NFSDDBG_FACILITY		NFSDDBG_PROC
  
  static inline void
  fh_dup2(struct svc_fh *dst, struct svc_fh *src)
  {
  	fh_put(dst);
  	dget(src->fh_dentry);
  	if (src->fh_export)
  		cache_get(&src->fh_export->h);
  	*dst = *src;
  }

  static __be32

  do_open_permission(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open, int accmode)

  {

  	__be32 status;

  
  	if (open->op_truncate &&
  		!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
  		return nfserr_inval;

  	if (open->op_share_access & NFS4_SHARE_ACCESS_READ)

  		accmode |= NFSD_MAY_READ;

  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)

  		accmode |= (NFSD_MAY_WRITE | NFSD_MAY_TRUNC);

  	if (open->op_share_deny & NFS4_SHARE_DENY_WRITE)

  		accmode |= NFSD_MAY_WRITE;

  
  	status = fh_verify(rqstp, current_fh, S_IFREG, accmode);
  
  	return status;
  }

  static __be32

  do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
  {
  	struct svc_fh resfh;

  	__be32 status;

  	int created = 0;

  
  	fh_init(&resfh, NFS4_FHSIZE);
  	open->op_truncate = 0;
  
  	if (open->op_create) {
  		/*
  		 * Note: create modes (UNCHECKED,GUARDED...) are the same
  		 * in NFSv4 as in v3.
  		 */
  		status = nfsd_create_v3(rqstp, current_fh, open->op_fname.data,
  					open->op_fname.len, &open->op_iattr,
  					&resfh, open->op_createmode,

  					(u32 *)open->op_verf.data,
  					&open->op_truncate, &created);
  
  		/* If we ever decide to use different attrs to store the
  		 * verifier in nfsd_create_v3, then we'll need to change this
  		 */
  		if (open->op_createmode == NFS4_CREATE_EXCLUSIVE && status == 0)
  			open->op_bmval[1] |= (FATTR4_WORD1_TIME_ACCESS |
  						FATTR4_WORD1_TIME_MODIFY);

  	} else {

  		status = nfsd_lookup(rqstp, current_fh,
  				     open->op_fname.data, open->op_fname.len, &resfh);
  		fh_unlock(current_fh);
  	}

  	if (status)
  		goto out;

  	set_change_info(&open->op_cinfo, current_fh);

  	/* set reply cache */
  	fh_dup2(current_fh, &resfh);
  	open->op_stateowner->so_replay.rp_openfh_len = resfh.fh_handle.fh_size;
  	memcpy(open->op_stateowner->so_replay.rp_openfh,
  			&resfh.fh_handle.fh_base, resfh.fh_handle.fh_size);

  	if (!created)

  		status = do_open_permission(rqstp, current_fh, open,
  					    NFSD_MAY_NOP);

  out:

  	fh_put(&resfh);
  	return status;
  }

  static __be32

  do_open_fhandle(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
  {

  	__be32 status;

  
  	/* Only reclaims from previously confirmed clients are valid */
  	if ((status = nfs4_check_open_reclaim(&open->op_clientid)))
  		return status;
  
  	/* We don't know the target directory, and therefore can not
  	* set the change info
  	*/
  
  	memset(&open->op_cinfo, 0, sizeof(struct nfsd4_change_info));
  
  	/* set replay cache */
  	open->op_stateowner->so_replay.rp_openfh_len = current_fh->fh_handle.fh_size;
  	memcpy(open->op_stateowner->so_replay.rp_openfh,
  		&current_fh->fh_handle.fh_base,
  		current_fh->fh_handle.fh_size);
  
  	open->op_truncate = (open->op_iattr.ia_valid & ATTR_SIZE) &&
  		(open->op_iattr.ia_size == 0);

  	status = do_open_permission(rqstp, current_fh, open,
  				    NFSD_MAY_OWNER_OVERRIDE);

  
  	return status;
  }

  static __be32

  nfsd4_open(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,

  	   struct nfsd4_open *open)

  {

  	__be32 status;

  	dprintk("NFSD: nfsd4_open filename %.*s op_stateowner %p
  ",
  		(int)open->op_fname.len, open->op_fname.data,
  		open->op_stateowner);

  	/* This check required by spec. */
  	if (open->op_create && open->op_claim_type != NFS4_OPEN_CLAIM_NULL)
  		return nfserr_inval;
  
  	nfs4_lock_state();
  
  	/* check seqid for replay. set nfs4_owner */
  	status = nfsd4_process_open1(open);

  	if (status == nfserr_replay_me) {

  		struct nfs4_replay *rp = &open->op_stateowner->so_replay;

  		fh_put(&cstate->current_fh);
  		cstate->current_fh.fh_handle.fh_size = rp->rp_openfh_len;
  		memcpy(&cstate->current_fh.fh_handle.fh_base, rp->rp_openfh,

  				rp->rp_openfh_len);

  		status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);

  		if (status)
  			dprintk("nfsd4_open: replay failed"
  				" restoring previous filehandle
  ");
  		else

  			status = nfserr_replay_me;

  	}
  	if (status)
  		goto out;

  
  	/* Openowner is now set, so sequence id will get bumped.  Now we need
  	 * these checks before we do any creates: */

  	status = nfserr_grace;

  	if (nfs4_in_grace() && open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)

  		goto out;
  	status = nfserr_no_grace;

  	if (!nfs4_in_grace() && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)

  		goto out;

  	switch (open->op_claim_type) {

  		case NFS4_OPEN_CLAIM_DELEGATE_CUR:
  			status = nfserr_inval;
  			if (open->op_create)
  				goto out;
  			/* fall through */

  		case NFS4_OPEN_CLAIM_NULL:
  			/*
  			 * (1) set CURRENT_FH to the file being opened,
  			 * creating it if necessary, (2) set open->op_cinfo,
  			 * (3) set open->op_truncate if the file is to be
  			 * truncated after opening, (4) do permission checking.
  			 */

  			status = do_open_lookup(rqstp, &cstate->current_fh,
  						open);

  			if (status)
  				goto out;
  			break;
  		case NFS4_OPEN_CLAIM_PREVIOUS:

  			open->op_stateowner->so_confirmed = 1;

  			/*
  			 * The CURRENT_FH is already set to the file being
  			 * opened.  (1) set open->op_cinfo, (2) set
  			 * open->op_truncate if the file is to be truncated
  			 * after opening, (3) do permission checking.
  			*/

  			status = do_open_fhandle(rqstp, &cstate->current_fh,
  						 open);

  			if (status)
  				goto out;
  			break;

               	case NFS4_OPEN_CLAIM_DELEGATE_PREV:

  			open->op_stateowner->so_confirmed = 1;

  			dprintk("NFSD: unsupported OPEN claim type %d
  ",

  				open->op_claim_type);
  			status = nfserr_notsupp;
  			goto out;
  		default:

  			dprintk("NFSD: Invalid OPEN claim type %d
  ",

  				open->op_claim_type);
  			status = nfserr_inval;
  			goto out;
  	}
  	/*
  	 * nfsd4_process_open2() does the actual opening of the file.  If
  	 * successful, it (1) truncates the file if open->op_truncate was
  	 * set, (2) sets open->op_stateid, (3) sets open->op_delegation.
  	 */

  	status = nfsd4_process_open2(rqstp, &cstate->current_fh, open);

  out:

  	if (open->op_stateowner) {

  		nfs4_get_stateowner(open->op_stateowner);

  		cstate->replay_owner = open->op_stateowner;

  	}

  	nfs4_unlock_state();
  	return status;
  }
  
  /*
   * filehandle-manipulating ops.
   */

  static __be32

  nfsd4_getfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	    struct svc_fh **getfh)

  {

  	if (!cstate->current_fh.fh_dentry)

  		return nfserr_nofilehandle;

  	*getfh = &cstate->current_fh;

  	return nfs_ok;
  }

  static __be32

  nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	    struct nfsd4_putfh *putfh)

  {

  	fh_put(&cstate->current_fh);
  	cstate->current_fh.fh_handle.fh_size = putfh->pf_fhlen;
  	memcpy(&cstate->current_fh.fh_handle.fh_base, putfh->pf_fhval,
  	       putfh->pf_fhlen);

  	return fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);

  }

  static __be32

  nfsd4_putrootfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  		void *arg)

  {

  	__be32 status;

  	fh_put(&cstate->current_fh);

  	status = exp_pseudoroot(rqstp, &cstate->current_fh);

  	return status;
  }

  static __be32

  nfsd4_restorefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  		void *arg)

  {

  	if (!cstate->save_fh.fh_dentry)

  		return nfserr_restorefh;

  	fh_dup2(&cstate->current_fh, &cstate->save_fh);

  	return nfs_ok;
  }

  static __be32

  nfsd4_savefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     void *arg)

  {

  	if (!cstate->current_fh.fh_dentry)

  		return nfserr_nofilehandle;

  	fh_dup2(&cstate->save_fh, &cstate->current_fh);

  	return nfs_ok;
  }
  
  /*
   * misc nfsv4 ops
   */

  static __be32

  nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_access *access)

  {
  	if (access->ac_req_access & ~NFS3_ACCESS_FULL)
  		return nfserr_inval;
  
  	access->ac_resp_access = access->ac_req_access;

  	return nfsd_access(rqstp, &cstate->current_fh, &access->ac_resp_access,
  			   &access->ac_supported);

  }

  static __be32

  nfsd4_commit(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_commit *commit)

  {

  	__be32 status;

  
  	u32 *p = (u32 *)commit->co_verf.data;
  	*p++ = nfssvc_boot.tv_sec;
  	*p++ = nfssvc_boot.tv_usec;

  	status = nfsd_commit(rqstp, &cstate->current_fh, commit->co_offset,
  			     commit->co_count);

  	if (status == nfserr_symlink)
  		status = nfserr_inval;
  	return status;
  }

  static __be32

  nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_create *create)

  {
  	struct svc_fh resfh;

  	__be32 status;

  	dev_t rdev;
  
  	fh_init(&resfh, NFS4_FHSIZE);

  	status = fh_verify(rqstp, &cstate->current_fh, S_IFDIR,
  			   NFSD_MAY_CREATE);

  	if (status == nfserr_symlink)
  		status = nfserr_notdir;
  	if (status)
  		return status;
  
  	switch (create->cr_type) {
  	case NF4LNK:
  		/* ugh! we have to null-terminate the linktext, or
  		 * vfs_symlink() will choke.  it is always safe to
  		 * null-terminate by brute force, since at worst we
  		 * will overwrite the first byte of the create namelen
  		 * in the XDR buffer, which has already been extracted
  		 * during XDR decode.
  		 */
  		create->cr_linkname[create->cr_linklen] = 0;

  		status = nfsd_symlink(rqstp, &cstate->current_fh,
  				      create->cr_name, create->cr_namelen,
  				      create->cr_linkname, create->cr_linklen,
  				      &resfh, &create->cr_iattr);

  		break;
  
  	case NF4BLK:
  		rdev = MKDEV(create->cr_specdata1, create->cr_specdata2);
  		if (MAJOR(rdev) != create->cr_specdata1 ||
  		    MINOR(rdev) != create->cr_specdata2)
  			return nfserr_inval;

  		status = nfsd_create(rqstp, &cstate->current_fh,
  				     create->cr_name, create->cr_namelen,
  				     &create->cr_iattr, S_IFBLK, rdev, &resfh);

  		break;
  
  	case NF4CHR:
  		rdev = MKDEV(create->cr_specdata1, create->cr_specdata2);
  		if (MAJOR(rdev) != create->cr_specdata1 ||
  		    MINOR(rdev) != create->cr_specdata2)
  			return nfserr_inval;

  		status = nfsd_create(rqstp, &cstate->current_fh,
  				     create->cr_name, create->cr_namelen,
  				     &create->cr_iattr,S_IFCHR, rdev, &resfh);

  		break;
  
  	case NF4SOCK:

  		status = nfsd_create(rqstp, &cstate->current_fh,
  				     create->cr_name, create->cr_namelen,
  				     &create->cr_iattr, S_IFSOCK, 0, &resfh);

  		break;
  
  	case NF4FIFO:

  		status = nfsd_create(rqstp, &cstate->current_fh,
  				     create->cr_name, create->cr_namelen,
  				     &create->cr_iattr, S_IFIFO, 0, &resfh);

  		break;
  
  	case NF4DIR:
  		create->cr_iattr.ia_valid &= ~ATTR_SIZE;

  		status = nfsd_create(rqstp, &cstate->current_fh,
  				     create->cr_name, create->cr_namelen,
  				     &create->cr_iattr, S_IFDIR, 0, &resfh);

  		break;
  
  	default:
  		status = nfserr_badtype;
  	}
  
  	if (!status) {

  		fh_unlock(&cstate->current_fh);
  		set_change_info(&create->cr_cinfo, &cstate->current_fh);
  		fh_dup2(&cstate->current_fh, &resfh);

  	}
  
  	fh_put(&resfh);
  	return status;
  }

  static __be32

  nfsd4_getattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      struct nfsd4_getattr *getattr)

  {

  	__be32 status;

  	status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);

  	if (status)
  		return status;
  
  	if (getattr->ga_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
  		return nfserr_inval;
  
  	getattr->ga_bmval[0] &= NFSD_SUPPORTED_ATTRS_WORD0;
  	getattr->ga_bmval[1] &= NFSD_SUPPORTED_ATTRS_WORD1;

  	getattr->ga_fhp = &cstate->current_fh;

  	return nfs_ok;
  }

  static __be32

  nfsd4_link(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	   struct nfsd4_link *link)

  {

  	__be32 status = nfserr_nofilehandle;

  	if (!cstate->save_fh.fh_dentry)

  		return status;

  	status = nfsd_link(rqstp, &cstate->current_fh,
  			   link->li_name, link->li_namelen, &cstate->save_fh);

  	if (!status)

  		set_change_info(&link->li_cinfo, &cstate->current_fh);

  	return status;
  }

  static __be32

  nfsd4_lookupp(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      void *arg)

  {
  	struct svc_fh tmp_fh;

  	__be32 ret;

  
  	fh_init(&tmp_fh, NFS4_FHSIZE);

  	ret = exp_pseudoroot(rqstp, &tmp_fh);
  	if (ret)

  		return ret;

  	if (tmp_fh.fh_dentry == cstate->current_fh.fh_dentry) {

  		fh_put(&tmp_fh);
  		return nfserr_noent;
  	}
  	fh_put(&tmp_fh);

  	return nfsd_lookup(rqstp, &cstate->current_fh,
  			   "..", 2, &cstate->current_fh);

  }

  static __be32

  nfsd4_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_lookup *lookup)

  {

  	return nfsd_lookup(rqstp, &cstate->current_fh,
  			   lookup->lo_name, lookup->lo_len,
  			   &cstate->current_fh);

  }

  static __be32

  nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	   struct nfsd4_read *read)

  {

  	__be32 status;

  
  	/* no need to check permission - this will be done in nfsd_read() */

  	read->rd_filp = NULL;

  	if (read->rd_offset >= OFFSET_MAX)
  		return nfserr_inval;
  
  	nfs4_lock_state();
  	/* check stateid */

  	if ((status = nfs4_preprocess_stateid_op(&cstate->current_fh,
  				&read->rd_stateid,

  				CHECK_FH | RD_STATE, &read->rd_filp))) {

  		dprintk("NFSD: nfsd4_read: couldn't process stateid!
  ");
  		goto out;
  	}

  	if (read->rd_filp)
  		get_file(read->rd_filp);

  	status = nfs_ok;
  out:
  	nfs4_unlock_state();
  	read->rd_rqstp = rqstp;

  	read->rd_fhp = &cstate->current_fh;

  	return status;
  }

  static __be32

  nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      struct nfsd4_readdir *readdir)

  {
  	u64 cookie = readdir->rd_cookie;
  	static const nfs4_verifier zeroverf;
  
  	/* no need to check permission - this will be done in nfsd_readdir() */
  
  	if (readdir->rd_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
  		return nfserr_inval;
  
  	readdir->rd_bmval[0] &= NFSD_SUPPORTED_ATTRS_WORD0;
  	readdir->rd_bmval[1] &= NFSD_SUPPORTED_ATTRS_WORD1;
  
  	if ((cookie > ~(u32)0) || (cookie == 1) || (cookie == 2) ||
  	    (cookie == 0 && memcmp(readdir->rd_verf.data, zeroverf.data, NFS4_VERIFIER_SIZE)))
  		return nfserr_bad_cookie;
  
  	readdir->rd_rqstp = rqstp;

  	readdir->rd_fhp = &cstate->current_fh;

  	return nfs_ok;
  }

  static __be32

  nfsd4_readlink(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	       struct nfsd4_readlink *readlink)

  {
  	readlink->rl_rqstp = rqstp;

  	readlink->rl_fhp = &cstate->current_fh;

  	return nfs_ok;
  }

  static __be32

  nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_remove *remove)

  {

  	__be32 status;

  	if (nfs4_in_grace())
  		return nfserr_grace;

  	status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
  			     remove->rm_name, remove->rm_namelen);

  	if (status == nfserr_symlink)
  		return nfserr_notdir;
  	if (!status) {

  		fh_unlock(&cstate->current_fh);
  		set_change_info(&remove->rm_cinfo, &cstate->current_fh);

  	}
  	return status;
  }

  static __be32

  nfsd4_rename(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_rename *rename)

  {

  	__be32 status = nfserr_nofilehandle;

  	if (!cstate->save_fh.fh_dentry)

  		return status;

  	if (nfs4_in_grace() && !(cstate->save_fh.fh_export->ex_flags

  					& NFSEXP_NOSUBTREECHECK))
  		return nfserr_grace;

  	status = nfsd_rename(rqstp, &cstate->save_fh, rename->rn_sname,
  			     rename->rn_snamelen, &cstate->current_fh,

  			     rename->rn_tname, rename->rn_tnamelen);
  
  	/* the underlying filesystem returns different error's than required
  	 * by NFSv4. both save_fh and current_fh have been verified.. */
  	if (status == nfserr_isdir)
  		status = nfserr_exist;
  	else if ((status == nfserr_notdir) &&

                    (S_ISDIR(cstate->save_fh.fh_dentry->d_inode->i_mode) &&
                     S_ISDIR(cstate->current_fh.fh_dentry->d_inode->i_mode)))

  		status = nfserr_exist;
  	else if (status == nfserr_symlink)
  		status = nfserr_notdir;
  
  	if (!status) {

  		set_change_info(&rename->rn_sinfo, &cstate->current_fh);
  		set_change_info(&rename->rn_tinfo, &cstate->save_fh);

  	}
  	return status;
  }

  static __be32

  nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      struct nfsd4_secinfo *secinfo)
  {
  	struct svc_fh resfh;
  	struct svc_export *exp;
  	struct dentry *dentry;
  	__be32 err;
  
  	fh_init(&resfh, NFS4_FHSIZE);
  	err = nfsd_lookup_dentry(rqstp, &cstate->current_fh,
  				    secinfo->si_name, secinfo->si_namelen,
  				    &exp, &dentry);
  	if (err)
  		return err;
  	if (dentry->d_inode == NULL) {
  		exp_put(exp);
  		err = nfserr_noent;
  	} else
  		secinfo->si_exp = exp;
  	dput(dentry);
  	return err;
  }
  
  static __be32

  nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      struct nfsd4_setattr *setattr)

  {

  	__be32 status = nfs_ok;

  	if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
  		nfs4_lock_state();

  		status = nfs4_preprocess_stateid_op(&cstate->current_fh,

  			&setattr->sa_stateid, CHECK_FH | WR_STATE, NULL);

  		nfs4_unlock_state();

  		if (status) {

  			dprintk("NFSD: nfsd4_setattr: couldn't process stateid!
  ");

  			return status;
  		}

  	}

  	status = mnt_want_write(cstate->current_fh.fh_export->ex_path.mnt);
  	if (status)
  		return status;

  	status = nfs_ok;
  	if (setattr->sa_acl != NULL)

  		status = nfsd4_set_nfs4_acl(rqstp, &cstate->current_fh,
  					    setattr->sa_acl);

  	if (status)

  		goto out;

  	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,

  				0, (time_t)0);

  out:
  	mnt_drop_write(cstate->current_fh.fh_export->ex_path.mnt);

  	return status;
  }

  static __be32

  nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	    struct nfsd4_write *write)

  {
  	stateid_t *stateid = &write->wr_stateid;
  	struct file *filp = NULL;
  	u32 *p;

  	__be32 status = nfs_ok;

  
  	/* no need to check permission - this will be done in nfsd_write() */
  
  	if (write->wr_offset >= OFFSET_MAX)
  		return nfserr_inval;
  
  	nfs4_lock_state();

  	status = nfs4_preprocess_stateid_op(&cstate->current_fh, stateid,

  					CHECK_FH | WR_STATE, &filp);

  	if (filp)
  		get_file(filp);

  	nfs4_unlock_state();

  	if (status) {
  		dprintk("NFSD: nfsd4_write: couldn't process stateid!
  ");
  		return status;
  	}

  	write->wr_bytes_written = write->wr_buflen;
  	write->wr_how_written = write->wr_stable_how;
  	p = (u32 *)write->wr_verifier.data;
  	*p++ = nfssvc_boot.tv_sec;
  	*p++ = nfssvc_boot.tv_usec;

  	status =  nfsd_write(rqstp, &cstate->current_fh, filp,
  			     write->wr_offset, rqstp->rq_vec, write->wr_vlen,
  			     write->wr_buflen, &write->wr_how_written);

  	if (filp)
  		fput(filp);

  
  	if (status == nfserr_symlink)
  		status = nfserr_inval;
  	return status;

  }
  
  /* This routine never returns NFS_OK!  If there are no other errors, it
   * will return NFSERR_SAME or NFSERR_NOT_SAME depending on whether the
   * attributes matched.  VERIFY is implemented by mapping NFSERR_SAME
   * to NFS_OK after the call; NVERIFY by mapping NFSERR_NOT_SAME to NFS_OK.
   */

  static __be32

  _nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,

  	     struct nfsd4_verify *verify)

  {

  	__be32 *buf, *p;

  	int count;

  	__be32 status;

  	status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);

  	if (status)
  		return status;
  
  	if ((verify->ve_bmval[0] & ~NFSD_SUPPORTED_ATTRS_WORD0)
  	    || (verify->ve_bmval[1] & ~NFSD_SUPPORTED_ATTRS_WORD1))
  		return nfserr_attrnotsupp;
  	if ((verify->ve_bmval[0] & FATTR4_WORD0_RDATTR_ERROR)
  	    || (verify->ve_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1))
  		return nfserr_inval;
  	if (verify->ve_attrlen & 3)
  		return nfserr_inval;
  
  	/* count in words:
  	 *   bitmap_len(1) + bitmap(2) + attr_len(1) = 4
  	 */
  	count = 4 + (verify->ve_attrlen >> 2);
  	buf = kmalloc(count << 2, GFP_KERNEL);
  	if (!buf)
  		return nfserr_resource;

  	status = nfsd4_encode_fattr(&cstate->current_fh,
  				    cstate->current_fh.fh_export,
  				    cstate->current_fh.fh_dentry, buf,

  				    &count, verify->ve_bmval,

  				    rqstp, 0);

  
  	/* this means that nfsd4_encode_fattr() ran out of space */
  	if (status == nfserr_resource && count == 0)
  		status = nfserr_not_same;
  	if (status)
  		goto out_kfree;
  
  	p = buf + 3;
  	status = nfserr_not_same;
  	if (ntohl(*p++) != verify->ve_attrlen)
  		goto out_kfree;
  	if (!memcmp(p, verify->ve_attrval, verify->ve_attrlen))
  		status = nfserr_same;
  
  out_kfree:
  	kfree(buf);
  	return status;
  }

  static __be32
  nfsd4_nverify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	      struct nfsd4_verify *verify)
  {
  	__be32 status;
  
  	status = _nfsd4_verify(rqstp, cstate, verify);
  	return status == nfserr_not_same ? nfs_ok : status;
  }
  
  static __be32
  nfsd4_verify(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  	     struct nfsd4_verify *verify)
  {
  	__be32 status;
  
  	status = _nfsd4_verify(rqstp, cstate, verify);
  	return status == nfserr_same ? nfs_ok : status;
  }

  /*
   * NULL call.
   */

  static __be32

  nfsd4_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
  {
  	return nfs_ok;
  }

  static inline void nfsd4_increment_op_stats(u32 opnum)
  {
  	if (opnum >= FIRST_NFS4_OP && opnum <= LAST_NFS4_OP)
  		nfsdstats.nfs4_opcount[opnum]++;
  }

  static void cstate_free(struct nfsd4_compound_state *cstate)
  {
  	if (cstate == NULL)
  		return;
  	fh_put(&cstate->current_fh);
  	fh_put(&cstate->save_fh);

  	BUG_ON(cstate->replay_owner);

  	kfree(cstate);
  }
  
  static struct nfsd4_compound_state *cstate_alloc(void)
  {
  	struct nfsd4_compound_state *cstate;
  
  	cstate = kmalloc(sizeof(struct nfsd4_compound_state), GFP_KERNEL);
  	if (cstate == NULL)
  		return NULL;
  	fh_init(&cstate->current_fh, NFS4_FHSIZE);
  	fh_init(&cstate->save_fh, NFS4_FHSIZE);

  	cstate->replay_owner = NULL;

  	return cstate;
  }

  typedef __be32(*nfsd4op_func)(struct svc_rqst *, struct nfsd4_compound_state *,
  			      void *);
  
  struct nfsd4_operation {
  	nfsd4op_func op_func;
  	u32 op_flags;

  /* Most ops require a valid current filehandle; a few don't: */
  #define ALLOWED_WITHOUT_FH 1

  /* GETATTR and ops not listed as returning NFS4ERR_MOVED: */

  #define ALLOWED_ON_ABSENT_FS 2

  	char *op_name;

  };
  
  static struct nfsd4_operation nfsd4_ops[];

  static const char *nfsd4_op_name(unsigned opnum);

  /*
   * COMPOUND call.
   */

  static __be32

  nfsd4_proc_compound(struct svc_rqst *rqstp,
  		    struct nfsd4_compoundargs *args,
  		    struct nfsd4_compoundres *resp)
  {
  	struct nfsd4_op	*op;

  	struct nfsd4_operation *opdesc;

  	struct nfsd4_compound_state *cstate = NULL;

  	int		slack_bytes;

  	__be32		status;

  	resp->xbuf = &rqstp->rq_res;
  	resp->p = rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len;
  	resp->tagp = resp->p;
  	/* reserve space for: taglen, tag, and opcnt */
  	resp->p += 2 + XDR_QUADLEN(args->taglen);
  	resp->end = rqstp->rq_res.head[0].iov_base + PAGE_SIZE;
  	resp->taglen = args->taglen;
  	resp->tag = args->tag;
  	resp->opcnt = 0;
  	resp->rqstp = rqstp;
  
  	/*
  	 * According to RFC3010, this takes precedence over all other errors.
  	 */
  	status = nfserr_minor_vers_mismatch;
  	if (args->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
  		goto out;

  	status = nfserr_resource;
  	cstate = cstate_alloc();
  	if (cstate == NULL)
  		goto out;

  	status = nfs_ok;
  	while (!status && resp->opcnt < args->opcnt) {
  		op = &args->ops[resp->opcnt++];

  		dprintk("nfsv4 compound op #%d/%d: %d (%s)
  ",
  			resp->opcnt, args->opcnt, op->opnum,
  			nfsd4_op_name(op->opnum));

  		/*
  		 * The XDR decode routines may have pre-set op->status;
  		 * for example, if there is a miscellaneous XDR error
  		 * it will be set to nfserr_bad_xdr.
  		 */
  		if (op->status)
  			goto encode_op;
  
  		/* We must be able to encode a successful response to
  		 * this operation, with enough room left over to encode a
  		 * failed response to the next operation.  If we don't
  		 * have enough room, fail with ERR_RESOURCE.
  		 */

  		slack_bytes = (char *)resp->end - (char *)resp->p;
  		if (slack_bytes < COMPOUND_SLACK_SPACE
  				+ COMPOUND_ERR_SLACK_SPACE) {
  			BUG_ON(slack_bytes < COMPOUND_ERR_SLACK_SPACE);

  			op->status = nfserr_resource;
  			goto encode_op;
  		}

  		opdesc = &nfsd4_ops[op->opnum];

  		if (!cstate->current_fh.fh_dentry) {

  			if (!(opdesc->op_flags & ALLOWED_WITHOUT_FH)) {

  				op->status = nfserr_nofilehandle;
  				goto encode_op;
  			}

  		} else if (cstate->current_fh.fh_export->ex_fslocs.migrated &&
  			  !(opdesc->op_flags & ALLOWED_ON_ABSENT_FS)) {

  			op->status = nfserr_moved;

  			goto encode_op;
  		}

  
  		if (opdesc->op_func)
  			op->status = opdesc->op_func(rqstp, cstate, &op->u);
  		else

  			BUG_ON(op->status == nfs_ok);

  
  encode_op:

  		if (op->status == nfserr_replay_me) {

  			op->replay = &cstate->replay_owner->so_replay;

  			nfsd4_encode_replay(resp, op);
  			status = op->status = op->replay->rp_status;
  		} else {
  			nfsd4_encode_operation(resp, op);
  			status = op->status;
  		}

  		if (cstate->replay_owner) {
  			nfs4_put_stateowner(cstate->replay_owner);
  			cstate->replay_owner = NULL;

  		}

  		/* XXX Ugh, we need to get rid of this kind of special case: */
  		if (op->opnum == OP_READ && op->u.read.rd_filp)
  			fput(op->u.read.rd_filp);

  
  		nfsd4_increment_op_stats(op->opnum);

  	}

  	cstate_free(cstate);

  out:
  	nfsd4_release_compoundargs(args);

  	dprintk("nfsv4 compound returned %d
  ", ntohl(status));

  	return status;
  }

  static struct nfsd4_operation nfsd4_ops[OP_RELEASE_LOCKOWNER+1] = {
  	[OP_ACCESS] = {
  		.op_func = (nfsd4op_func)nfsd4_access,

  		.op_name = "OP_ACCESS",

  	},
  	[OP_CLOSE] = {
  		.op_func = (nfsd4op_func)nfsd4_close,

  		.op_name = "OP_CLOSE",

  	},
  	[OP_COMMIT] = {
  		.op_func = (nfsd4op_func)nfsd4_commit,

  		.op_name = "OP_COMMIT",

  	},
  	[OP_CREATE] = {
  		.op_func = (nfsd4op_func)nfsd4_create,

  		.op_name = "OP_CREATE",

  	},
  	[OP_DELEGRETURN] = {
  		.op_func = (nfsd4op_func)nfsd4_delegreturn,

  		.op_name = "OP_DELEGRETURN",

  	},
  	[OP_GETATTR] = {
  		.op_func = (nfsd4op_func)nfsd4_getattr,

  		.op_flags = ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_GETATTR",

  	},
  	[OP_GETFH] = {
  		.op_func = (nfsd4op_func)nfsd4_getfh,

  		.op_name = "OP_GETFH",

  	},
  	[OP_LINK] = {
  		.op_func = (nfsd4op_func)nfsd4_link,

  		.op_name = "OP_LINK",

  	},
  	[OP_LOCK] = {
  		.op_func = (nfsd4op_func)nfsd4_lock,

  		.op_name = "OP_LOCK",

  	},
  	[OP_LOCKT] = {
  		.op_func = (nfsd4op_func)nfsd4_lockt,

  		.op_name = "OP_LOCKT",

  	},
  	[OP_LOCKU] = {
  		.op_func = (nfsd4op_func)nfsd4_locku,

  		.op_name = "OP_LOCKU",

  	},
  	[OP_LOOKUP] = {
  		.op_func = (nfsd4op_func)nfsd4_lookup,

  		.op_name = "OP_LOOKUP",

  	},
  	[OP_LOOKUPP] = {
  		.op_func = (nfsd4op_func)nfsd4_lookupp,

  		.op_name = "OP_LOOKUPP",

  	},
  	[OP_NVERIFY] = {
  		.op_func = (nfsd4op_func)nfsd4_nverify,

  		.op_name = "OP_NVERIFY",

  	},
  	[OP_OPEN] = {
  		.op_func = (nfsd4op_func)nfsd4_open,

  		.op_name = "OP_OPEN",

  	},
  	[OP_OPEN_CONFIRM] = {
  		.op_func = (nfsd4op_func)nfsd4_open_confirm,

  		.op_name = "OP_OPEN_CONFIRM",

  	},
  	[OP_OPEN_DOWNGRADE] = {
  		.op_func = (nfsd4op_func)nfsd4_open_downgrade,

  		.op_name = "OP_OPEN_DOWNGRADE",

  	},
  	[OP_PUTFH] = {
  		.op_func = (nfsd4op_func)nfsd4_putfh,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_PUTFH",

  	},

  	[OP_PUTPUBFH] = {

  		/* unsupported, just for future reference: */

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_PUTPUBFH",

  	},

  	[OP_PUTROOTFH] = {
  		.op_func = (nfsd4op_func)nfsd4_putrootfh,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_PUTROOTFH",

  	},
  	[OP_READ] = {
  		.op_func = (nfsd4op_func)nfsd4_read,

  		.op_name = "OP_READ",

  	},
  	[OP_READDIR] = {
  		.op_func = (nfsd4op_func)nfsd4_readdir,

  		.op_name = "OP_READDIR",

  	},
  	[OP_READLINK] = {
  		.op_func = (nfsd4op_func)nfsd4_readlink,

  		.op_name = "OP_READLINK",

  	},
  	[OP_REMOVE] = {
  		.op_func = (nfsd4op_func)nfsd4_remove,

  		.op_name = "OP_REMOVE",

  	},
  	[OP_RENAME] = {

  		.op_name = "OP_RENAME",

  		.op_func = (nfsd4op_func)nfsd4_rename,
  	},
  	[OP_RENEW] = {
  		.op_func = (nfsd4op_func)nfsd4_renew,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_RENEW",

  	},
  	[OP_RESTOREFH] = {
  		.op_func = (nfsd4op_func)nfsd4_restorefh,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_RESTOREFH",

  	},
  	[OP_SAVEFH] = {
  		.op_func = (nfsd4op_func)nfsd4_savefh,

  		.op_name = "OP_SAVEFH",

  	},

  	[OP_SECINFO] = {
  		.op_func = (nfsd4op_func)nfsd4_secinfo,

  		.op_name = "OP_SECINFO",

  	},

  	[OP_SETATTR] = {
  		.op_func = (nfsd4op_func)nfsd4_setattr,

  		.op_name = "OP_SETATTR",

  	},
  	[OP_SETCLIENTID] = {
  		.op_func = (nfsd4op_func)nfsd4_setclientid,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_SETCLIENTID",

  	},
  	[OP_SETCLIENTID_CONFIRM] = {
  		.op_func = (nfsd4op_func)nfsd4_setclientid_confirm,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_SETCLIENTID_CONFIRM",

  	},
  	[OP_VERIFY] = {
  		.op_func = (nfsd4op_func)nfsd4_verify,

  		.op_name = "OP_VERIFY",

  	},
  	[OP_WRITE] = {
  		.op_func = (nfsd4op_func)nfsd4_write,

  		.op_name = "OP_WRITE",

  	},
  	[OP_RELEASE_LOCKOWNER] = {
  		.op_func = (nfsd4op_func)nfsd4_release_lockowner,

  		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,

  		.op_name = "OP_RELEASE_LOCKOWNER",

  	},
  };

  static const char *nfsd4_op_name(unsigned opnum)

  {
  	if (opnum < ARRAY_SIZE(nfsd4_ops))
  		return nfsd4_ops[opnum].op_name;
  	return "unknown_operation";
  }

  #define nfs4svc_decode_voidargs		NULL
  #define nfs4svc_release_void		NULL
  #define nfsd4_voidres			nfsd4_voidargs
  #define nfs4svc_release_compound	NULL
  struct nfsd4_voidargs { int dummy; };
  
  #define PROC(name, argt, rest, relt, cache, respsize)	\
   { (svc_procfunc) nfsd4_proc_##name,		\
     (kxdrproc_t) nfs4svc_decode_##argt##args,	\
     (kxdrproc_t) nfs4svc_encode_##rest##res,	\
     (kxdrproc_t) nfs4svc_release_##relt,		\
     sizeof(struct nfsd4_##argt##args),		\
     sizeof(struct nfsd4_##rest##res),		\
     0,						\
     cache,					\
     respsize,					\
   }
  
  /*
   * TODO: At the present time, the NFSv4 server does not do XID caching
   * of requests.  Implementing XID caching would not be a serious problem,
   * although it would require a mild change in interfaces since one
   * doesn't know whether an NFSv4 request is idempotent until after the
   * XDR decode.  However, XID caching totally confuses pynfs (Peter
   * Astrand's regression testsuite for NFSv4 servers), which reuses
   * XID's liberally, so I've left it unimplemented until pynfs generates
   * better XID's.
   */
  static struct svc_procedure		nfsd_procedures4[2] = {
    PROC(null,	 void,		void,		void,	  RC_NOCACHE, 1),

    PROC(compound, compound,	compound,	compound, RC_NOCACHE, NFSD_BUFSIZE/4)

  };
  
  struct svc_version	nfsd_version4 = {
  		.vs_vers	= 4,
  		.vs_nproc	= 2,
  		.vs_proc	= nfsd_procedures4,
  		.vs_dispatch	= nfsd_dispatch,
  		.vs_xdrsize	= NFS4_SVC_XDRSIZE,
  };
  
  /*
   * Local variables:
   *  c-basic-offset: 8
   * End:
   */