xref: /openbmc/linux/fs/nfsd/nfs4proc.c (revision 7e70570647827345352cf6c17461c9fa166f570a)

/*
 *  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);

		/*
		 * Following rfc 3530 14.2.16, use the returned bitmask
		 * to indicate which attributes we used to store the
		 * verifier:
		 */
		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);
	fh_dup2(current_fh, &resfh);

	/* set reply cache */
	fh_copy_shallow(&open->op_stateowner->so_replay.rp_openfh,
			&resfh.fh_handle);
	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 */
	fh_copy_shallow(&open->op_stateowner->so_replay.rp_openfh,
			&current_fh->fh_handle);

	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 void
copy_clientid(clientid_t *clid, struct nfsd4_session *session)
{
	struct nfsd4_sessionid *sid =
			(struct nfsd4_sessionid *)session->se_sessionid.data;

	clid->cl_boot = sid->clientid.cl_boot;
	clid->cl_id = sid->clientid.cl_id;
}

static __be32
nfsd4_open(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
	   struct nfsd4_open *open)
{
	__be32 status;
	struct nfsd4_compoundres *resp;

	dprintk("NFSD: nfsd4_open filename %.*s op_stateowner %p\n",
		(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;

	if (nfsd4_has_session(cstate))
		copy_clientid(&open->op_clientid, cstate->session);

	nfs4_lock_state();

	/* check seqid for replay. set nfs4_owner */
	resp = rqstp->rq_resp;
	status = nfsd4_process_open1(&resp->cstate, open);
	if (status == nfserr_replay_me) {
		struct nfs4_replay *rp = &open->op_stateowner->so_replay;
		fh_put(&cstate->current_fh);
		fh_copy_shallow(&cstate->current_fh.fh_handle,
				&rp->rp_openfh);
		status = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_NOP);
		if (status)
			dprintk("nfsd4_open: replay failed"
				" restoring previous filehandle\n");
		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 (locks_in_grace() && open->op_claim_type != NFS4_OPEN_CLAIM_PREVIOUS)
		goto out;
	status = nfserr_no_grace;
	if (!locks_in_grace() && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
		goto out;

	switch (open->op_claim_type) {
		case NFS4_OPEN_CLAIM_DELEGATE_CUR:
		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\n",
				open->op_claim_type);
			status = nfserr_notsupp;
			goto out;
		default:
			dprintk("NFSD: Invalid OPEN claim type %d\n",
				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_suppattrs0(cstate->minorversion);
	getattr->ga_bmval[1] &= nfsd_suppattrs1(cstate->minorversion);
	getattr->ga_bmval[2] &= nfsd_suppattrs2(cstate->minorversion);

	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, &read->rd_stateid,
						 RD_STATE, &read->rd_filp))) {
		dprintk("NFSD: nfsd4_read: couldn't process stateid!\n");
		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_suppattrs0(cstate->minorversion);
	readdir->rd_bmval[1] &= nfsd_suppattrs1(cstate->minorversion);
	readdir->rd_bmval[2] &= nfsd_suppattrs2(cstate->minorversion);

	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 (locks_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 (locks_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,
			&setattr->sa_stateid, WR_STATE, NULL);
		nfs4_unlock_state();
		if (status) {
			dprintk("NFSD: nfsd4_setattr: couldn't process stateid!\n");
			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;
	unsigned long cnt;

	/* 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, stateid, WR_STATE, &filp);
	if (filp)
		get_file(filp);
	nfs4_unlock_state();

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

	cnt = 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,
			     &cnt, &write->wr_how_written);
	if (filp)
		fput(filp);

	write->wr_bytes_written = cnt;

	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_suppattrs0(cstate->minorversion))
	    || (verify->ve_bmval[1] & ~nfsd_suppattrs1(cstate->minorversion))
	    || (verify->ve_bmval[2] & ~nfsd_suppattrs2(cstate->minorversion)))
		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;

	/* skip bitmap */
	p = buf + 1 + ntohl(buf[0]);
	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]++;
}

typedef __be32(*nfsd4op_func)(struct svc_rqst *, struct nfsd4_compound_state *,
			      void *);
enum nfsd4_op_flags {
	ALLOWED_WITHOUT_FH = 1 << 0,	/* No current filehandle required */
	ALLOWED_ON_ABSENT_FS = 2 << 0,	/* ops processed on absent fs */
	ALLOWED_AS_FIRST_OP = 3 << 0,	/* ops reqired first in compound */
};

struct nfsd4_operation {
	nfsd4op_func op_func;
	u32 op_flags;
	char *op_name;
};

static struct nfsd4_operation nfsd4_ops[];

static const char *nfsd4_op_name(unsigned opnum);

/*
 * This is a replay of a compound for which no cache entry pages
 * were used. Encode the sequence operation, and if cachethis is FALSE
 * encode the uncache rep error on the next operation.
 */
static __be32
nfsd4_enc_uncached_replay(struct nfsd4_compoundargs *args,
			 struct nfsd4_compoundres *resp)
{
	struct nfsd4_op *op;

	dprintk("--> %s resp->opcnt %d ce_cachethis %u \n", __func__,
		resp->opcnt, resp->cstate.slot->sl_cache_entry.ce_cachethis);

	/* Encode the replayed sequence operation */
	BUG_ON(resp->opcnt != 1);
	op = &args->ops[resp->opcnt - 1];
	nfsd4_encode_operation(resp, op);

	/*return nfserr_retry_uncached_rep in next operation. */
	if (resp->cstate.slot->sl_cache_entry.ce_cachethis == 0) {
		op = &args->ops[resp->opcnt++];
		op->status = nfserr_retry_uncached_rep;
		nfsd4_encode_operation(resp, op);
	}
	return op->status;
}

/*
 * Enforce NFSv4.1 COMPOUND ordering rules.
 *
 * TODO:
 * - enforce NFS4ERR_NOT_ONLY_OP,
 * - DESTROY_SESSION MUST be the final operation in the COMPOUND request.
 */
static bool nfs41_op_ordering_ok(struct nfsd4_compoundargs *args)
{
	if (args->minorversion && args->opcnt > 0) {
		struct nfsd4_op *op = &args->ops[0];
		return (op->status == nfserr_op_illegal) ||
		       (nfsd4_ops[op->opnum].op_flags & ALLOWED_AS_FIRST_OP);
	}
	return true;
}

/*
 * 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 = &resp->cstate;
	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;
	resp->cstate.minorversion = args->minorversion;
	resp->cstate.replay_owner = NULL;
	fh_init(&resp->cstate.current_fh, NFS4_FHSIZE);
	fh_init(&resp->cstate.save_fh, NFS4_FHSIZE);
	/* Use the deferral mechanism only for NFSv4.0 compounds */
	rqstp->rq_usedeferral = (args->minorversion == 0);

	/*
	 * According to RFC3010, this takes precedence over all other errors.
	 */
	status = nfserr_minor_vers_mismatch;
	if (args->minorversion > nfsd_supported_minorversion)
		goto out;

	if (!nfs41_op_ordering_ok(args)) {
		op = &args->ops[0];
		op->status = nfserr_sequence_pos;
		goto encode_op;
	}

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

		dprintk("nfsv4 compound op #%d/%d: %d (%s)\n",
			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:
		/* Only from SEQUENCE or CREATE_SESSION */
		if (resp->cstate.status == nfserr_replay_cache) {
			dprintk("%s NFS4.1 replay from cache\n", __func__);
			if (nfsd4_not_cached(resp))
				status = nfsd4_enc_uncached_replay(args, resp);
			else
				status = op->status;
			goto out;
		}
		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;
		}

		dprintk("nfsv4 compound op %p opcnt %d #%d: %d: status %d\n",
			args->ops, args->opcnt, resp->opcnt, op->opnum,
			be32_to_cpu(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);
	}
	if (!rqstp->rq_usedeferral && status == nfserr_dropit) {
		dprintk("%s Dropit - send NFS4ERR_DELAY\n", __func__);
		status = nfserr_jukebox;
	}

	resp->cstate.status = status;
	fh_put(&resp->cstate.current_fh);
	fh_put(&resp->cstate.save_fh);
	BUG_ON(resp->cstate.replay_owner);
out:
	nfsd4_release_compoundargs(args);
	/* Reset deferral mechanism for RPC deferrals */
	rqstp->rq_usedeferral = 1;
	dprintk("nfsv4 compound returned %d\n", ntohl(status));
	return status;
}

static struct nfsd4_operation nfsd4_ops[] = {
	[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] = {
		.op_func = (nfsd4op_func)nfsd4_putrootfh,
		.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",
	},

	/* NFSv4.1 operations */
	[OP_EXCHANGE_ID] = {
		.op_func = (nfsd4op_func)nfsd4_exchange_id,
		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
		.op_name = "OP_EXCHANGE_ID",
	},
	[OP_CREATE_SESSION] = {
		.op_func = (nfsd4op_func)nfsd4_create_session,
		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
		.op_name = "OP_CREATE_SESSION",
	},
	[OP_DESTROY_SESSION] = {
		.op_func = (nfsd4op_func)nfsd4_destroy_session,
		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
		.op_name = "OP_DESTROY_SESSION",
	},
	[OP_SEQUENCE] = {
		.op_func = (nfsd4op_func)nfsd4_sequence,
		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
		.op_name = "OP_SEQUENCE",
	},
};

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:
 */