nfs4xdr.c

/*
 *  Server-side XDR for NFSv4
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * TODO: Neil Brown made the following observation:  We currently
 * initially reserve NFSD_BUFSIZE space on the transmit queue and
 * never release any of that until the request is complete.
 * It would be good to calculate a new maximum response size while
 * decoding the COMPOUND, and call svc_reserve with this number
 * at the end of nfs4svc_decode_compoundargs.
 */

#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/utsname.h>
#include <linux/sunrpc/svcauth_gss.h>

#include "idmap.h"
#include "acl.h"
#include "xdr4.h"
#include "vfs.h"


#define NFSDDBG_FACILITY		NFSDDBG_XDR

/*
 * As per referral draft, the fsid for a referral MUST be different from the fsid of the containing
 * directory in order to indicate to the client that a filesystem boundary is present
 * We use a fixed fsid for a referral
 */
#define NFS4_REFERRAL_FSID_MAJOR	0x8000000ULL
#define NFS4_REFERRAL_FSID_MINOR	0x8000000ULL

static __be32
check_filename(char *str, int len, __be32 err)
{
	int i;

	if (len == 0)
		return nfserr_inval;
	if (isdotent(str, len))
		return err;
	for (i = 0; i < len; i++)
		if (str[i] == '/')
			return err;
	return 0;
}

#define DECODE_HEAD				\
	__be32 *p;				\
	__be32 status
#define DECODE_TAIL				\
	status = 0;				\
out:						\
	return status;				\
xdr_error:					\
	dprintk("NFSD: xdr error (%s:%d)\n",	\
			__FILE__, __LINE__);	\
	status = nfserr_bad_xdr;		\
	goto out

#define READ32(x)         (x) = ntohl(*p++)
#define READ64(x)         do {			\
	(x) = (u64)ntohl(*p++) << 32;		\
	(x) |= ntohl(*p++);			\
} while (0)
#define READTIME(x)       do {			\
	p++;					\
	(x) = ntohl(*p++);			\
	p++;					\
} while (0)
#define READMEM(x,nbytes) do {			\
	x = (char *)p;				\
	p += XDR_QUADLEN(nbytes);		\
} while (0)
#define SAVEMEM(x,nbytes) do {			\
	if (!(x = (p==argp->tmp || p == argp->tmpp) ? \
 		savemem(argp, p, nbytes) :	\
 		(char *)p)) {			\
		dprintk("NFSD: xdr error (%s:%d)\n", \
				__FILE__, __LINE__); \
		goto xdr_error;			\
		}				\
	p += XDR_QUADLEN(nbytes);		\
} while (0)
#define COPYMEM(x,nbytes) do {			\
	memcpy((x), p, nbytes);			\
	p += XDR_QUADLEN(nbytes);		\
} while (0)

/* READ_BUF, read_buf(): nbytes must be <= PAGE_SIZE */
#define READ_BUF(nbytes)  do {			\
	if (nbytes <= (u32)((char *)argp->end - (char *)argp->p)) {	\
		p = argp->p;			\
		argp->p += XDR_QUADLEN(nbytes);	\
	} else if (!(p = read_buf(argp, nbytes))) { \
		dprintk("NFSD: xdr error (%s:%d)\n", \
				__FILE__, __LINE__); \
		goto xdr_error;			\
	}					\
} while (0)

static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
{
	/* We want more bytes than seem to be available.
	 * Maybe we need a new page, maybe we have just run out
	 */
	unsigned int avail = (char *)argp->end - (char *)argp->p;
	__be32 *p;
	if (avail + argp->pagelen < nbytes)
		return NULL;
	if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */
		return NULL;
	/* ok, we can do it with the current plus the next page */
	if (nbytes <= sizeof(argp->tmp))
		p = argp->tmp;
	else {
		kfree(argp->tmpp);
		p = argp->tmpp = kmalloc(nbytes, GFP_KERNEL);
		if (!p)
			return NULL;
		
	}
	/*
	 * The following memcpy is safe because read_buf is always
	 * called with nbytes > avail, and the two cases above both
	 * guarantee p points to at least nbytes bytes.
	 */
	memcpy(p, argp->p, avail);
	/* step to next page */
	argp->p = page_address(argp->pagelist[0]);
	argp->pagelist++;
	if (argp->pagelen < PAGE_SIZE) {
		argp->end = argp->p + (argp->pagelen>>2);
		argp->pagelen = 0;
	} else {
		argp->end = argp->p + (PAGE_SIZE>>2);
		argp->pagelen -= PAGE_SIZE;
	}
	memcpy(((char*)p)+avail, argp->p, (nbytes - avail));
	argp->p += XDR_QUADLEN(nbytes - avail);
	return p;
}

static int zero_clientid(clientid_t *clid)
{
	return (clid->cl_boot == 0) && (clid->cl_id == 0);
}

static int
defer_free(struct nfsd4_compoundargs *argp,
		void (*release)(const void *), void *p)
{
	struct tmpbuf *tb;

	tb = kmalloc(sizeof(*tb), GFP_KERNEL);
	if (!tb)
		return -ENOMEM;
	tb->buf = p;
	tb->release = release;
	tb->next = argp->to_free;
	argp->to_free = tb;
	return 0;
}

static char *savemem(struct nfsd4_compoundargs *argp, __be32 *p, int nbytes)
{
	if (p == argp->tmp) {
		p = kmalloc(nbytes, GFP_KERNEL);
		if (!p)
			return NULL;
		memcpy(p, argp->tmp, nbytes);
	} else {
		BUG_ON(p != argp->tmpp);
		argp->tmpp = NULL;
	}
	if (defer_free(argp, kfree, p)) {
		kfree(p);
		return NULL;
	} else
		return (char *)p;
}

static __be32
nfsd4_decode_bitmap(struct nfsd4_compoundargs *argp, u32 *bmval)
{
	u32 bmlen;
	DECODE_HEAD;

	bmval[0] = 0;
	bmval[1] = 0;
	bmval[2] = 0;

	READ_BUF(4);
	READ32(bmlen);
	if (bmlen > 1000)
		goto xdr_error;

	READ_BUF(bmlen << 2);
	if (bmlen > 0)
		READ32(bmval[0]);
	if (bmlen > 1)
		READ32(bmval[1]);
	if (bmlen > 2)
		READ32(bmval[2]);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
		   struct iattr *iattr, struct nfs4_acl **acl)
{
	int expected_len, len = 0;
	u32 dummy32;
	char *buf;
	int host_err;

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

	READ_BUF(4);
	READ32(expected_len);

	if (bmval[0] & FATTR4_WORD0_SIZE) {
		READ_BUF(8);
		len += 8;
		READ64(iattr->ia_size);
		iattr->ia_valid |= ATTR_SIZE;
	}
	if (bmval[0] & FATTR4_WORD0_ACL) {
		int nace;
		struct nfs4_ace *ace;

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

		if (nace > NFS4_ACL_MAX)
			return nfserr_resource;

		*acl = nfs4_acl_new(nace);
		if (*acl == NULL) {
			host_err = -ENOMEM;
			goto out_nfserr;
		}
		defer_free(argp, kfree, *acl);

		(*acl)->naces = nace;
		for (ace = (*acl)->aces; ace < (*acl)->aces + nace; ace++) {
			READ_BUF(16); len += 16;
			READ32(ace->type);
			READ32(ace->flag);
			READ32(ace->access_mask);
			READ32(dummy32);
			READ_BUF(dummy32);
			len += XDR_QUADLEN(dummy32) << 2;
			READMEM(buf, dummy32);
			ace->whotype = nfs4_acl_get_whotype(buf, dummy32);
			status = nfs_ok;
			if (ace->whotype != NFS4_ACL_WHO_NAMED)
				ace->who = 0;
			else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
				status = nfsd_map_name_to_gid(argp->rqstp,
						buf, dummy32, &ace->who);
			else
				status = nfsd_map_name_to_uid(argp->rqstp,
						buf, dummy32, &ace->who);
			if (status)
				return status;
		}
	} else
		*acl = NULL;
	if (bmval[1] & FATTR4_WORD1_MODE) {
		READ_BUF(4);
		len += 4;
		READ32(iattr->ia_mode);
		iattr->ia_mode &= (S_IFMT | S_IALLUGO);
		iattr->ia_valid |= ATTR_MODE;
	}
	if (bmval[1] & FATTR4_WORD1_OWNER) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		READ_BUF(dummy32);
		len += (XDR_QUADLEN(dummy32) << 2);
		READMEM(buf, dummy32);
		if ((status = nfsd_map_name_to_uid(argp->rqstp, buf, dummy32, &iattr->ia_uid)))
			return status;
		iattr->ia_valid |= ATTR_UID;
	}
	if (bmval[1] & FATTR4_WORD1_OWNER_GROUP) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		READ_BUF(dummy32);
		len += (XDR_QUADLEN(dummy32) << 2);
		READMEM(buf, dummy32);
		if ((status = nfsd_map_name_to_gid(argp->rqstp, buf, dummy32, &iattr->ia_gid)))
			return status;
		iattr->ia_valid |= ATTR_GID;
	}
	if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		switch (dummy32) {
		case NFS4_SET_TO_CLIENT_TIME:
			/* We require the high 32 bits of 'seconds' to be 0, and we ignore
			   all 32 bits of 'nseconds'. */
			READ_BUF(12);
			len += 12;
			READ32(dummy32);
			if (dummy32)
				return nfserr_inval;
			READ32(iattr->ia_atime.tv_sec);
			READ32(iattr->ia_atime.tv_nsec);
			if (iattr->ia_atime.tv_nsec >= (u32)1000000000)
				return nfserr_inval;
			iattr->ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
			break;
		case NFS4_SET_TO_SERVER_TIME:
			iattr->ia_valid |= ATTR_ATIME;
			break;
		default:
			goto xdr_error;
		}
	}
	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		switch (dummy32) {
		case NFS4_SET_TO_CLIENT_TIME:
			/* We require the high 32 bits of 'seconds' to be 0, and we ignore
			   all 32 bits of 'nseconds'. */
			READ_BUF(12);
			len += 12;
			READ32(dummy32);
			if (dummy32)
				return nfserr_inval;
			READ32(iattr->ia_mtime.tv_sec);
			READ32(iattr->ia_mtime.tv_nsec);
			if (iattr->ia_mtime.tv_nsec >= (u32)1000000000)
				return nfserr_inval;
			iattr->ia_valid |= (ATTR_MTIME | ATTR_MTIME_SET);
			break;
		case NFS4_SET_TO_SERVER_TIME:
			iattr->ia_valid |= ATTR_MTIME;
			break;
		default:
			goto xdr_error;
		}
	}
	if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
	    || bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
	    || bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2)
		READ_BUF(expected_len - len);
	else if (len != expected_len)
		goto xdr_error;

	DECODE_TAIL;

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

static __be32
nfsd4_decode_stateid(struct nfsd4_compoundargs *argp, stateid_t *sid)
{
	DECODE_HEAD;

	READ_BUF(sizeof(stateid_t));
	READ32(sid->si_generation);
	COPYMEM(&sid->si_opaque, sizeof(stateid_opaque_t));

	DECODE_TAIL;
}

static __be32
nfsd4_decode_access(struct nfsd4_compoundargs *argp, struct nfsd4_access *access)
{
	DECODE_HEAD;

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

	DECODE_TAIL;
}

static __be32 nfsd4_decode_bind_conn_to_session(struct nfsd4_compoundargs *argp, struct nfsd4_bind_conn_to_session *bcts)
{
	DECODE_HEAD;
	u32 dummy;

	READ_BUF(NFS4_MAX_SESSIONID_LEN + 8);
	COPYMEM(bcts->sessionid.data, NFS4_MAX_SESSIONID_LEN);
	READ32(bcts->dir);
	/* XXX: Perhaps Tom Tucker could help us figure out how we
	 * should be using ctsa_use_conn_in_rdma_mode: */
	READ32(dummy);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_close(struct nfsd4_compoundargs *argp, struct nfsd4_close *close)
{
	DECODE_HEAD;

	close->cl_stateowner = NULL;
	READ_BUF(4);
	READ32(close->cl_seqid);
	return nfsd4_decode_stateid(argp, &close->cl_stateid);

	DECODE_TAIL;
}


static __be32
nfsd4_decode_commit(struct nfsd4_compoundargs *argp, struct nfsd4_commit *commit)
{
	DECODE_HEAD;

	READ_BUF(12);
	READ64(commit->co_offset);
	READ32(commit->co_count);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_create(struct nfsd4_compoundargs *argp, struct nfsd4_create *create)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(create->cr_type);
	switch (create->cr_type) {
	case NF4LNK:
		READ_BUF(4);
		READ32(create->cr_linklen);
		READ_BUF(create->cr_linklen);
		SAVEMEM(create->cr_linkname, create->cr_linklen);
		break;
	case NF4BLK:
	case NF4CHR:
		READ_BUF(8);
		READ32(create->cr_specdata1);
		READ32(create->cr_specdata2);
		break;
	case NF4SOCK:
	case NF4FIFO:
	case NF4DIR:
	default:
		break;
	}

	READ_BUF(4);
	READ32(create->cr_namelen);
	READ_BUF(create->cr_namelen);
	SAVEMEM(create->cr_name, create->cr_namelen);
	if ((status = check_filename(create->cr_name, create->cr_namelen, nfserr_inval)))
		return status;

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

	DECODE_TAIL;
}

static inline __be32
nfsd4_decode_delegreturn(struct nfsd4_compoundargs *argp, struct nfsd4_delegreturn *dr)
{
	return nfsd4_decode_stateid(argp, &dr->dr_stateid);
}

static inline __be32
nfsd4_decode_getattr(struct nfsd4_compoundargs *argp, struct nfsd4_getattr *getattr)
{
	return nfsd4_decode_bitmap(argp, getattr->ga_bmval);
}

static __be32
nfsd4_decode_link(struct nfsd4_compoundargs *argp, struct nfsd4_link *link)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(link->li_namelen);
	READ_BUF(link->li_namelen);
	SAVEMEM(link->li_name, link->li_namelen);
	if ((status = check_filename(link->li_name, link->li_namelen, nfserr_inval)))
		return status;

	DECODE_TAIL;
}

static __be32
nfsd4_decode_lock(struct nfsd4_compoundargs *argp, struct nfsd4_lock *lock)
{
	DECODE_HEAD;

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

	if (lock->lk_is_new) {
		READ_BUF(4);
		READ32(lock->lk_new_open_seqid);
		status = nfsd4_decode_stateid(argp, &lock->lk_new_open_stateid);
		if (status)
			return status;
		READ_BUF(8 + sizeof(clientid_t));
		READ32(lock->lk_new_lock_seqid);
		COPYMEM(&lock->lk_new_clientid, sizeof(clientid_t));
		READ32(lock->lk_new_owner.len);
		READ_BUF(lock->lk_new_owner.len);
		READMEM(lock->lk_new_owner.data, lock->lk_new_owner.len);
	} else {
		status = nfsd4_decode_stateid(argp, &lock->lk_old_lock_stateid);
		if (status)
			return status;
		READ_BUF(4);
		READ32(lock->lk_old_lock_seqid);
	}

	DECODE_TAIL;
}

static __be32
nfsd4_decode_lockt(struct nfsd4_compoundargs *argp, struct nfsd4_lockt *lockt)
{
	DECODE_HEAD;
		        
	READ_BUF(32);
	READ32(lockt->lt_type);
	if((lockt->lt_type < NFS4_READ_LT) || (lockt->lt_type > NFS4_WRITEW_LT))
		goto xdr_error;
	READ64(lockt->lt_offset);
	READ64(lockt->lt_length);
	COPYMEM(&lockt->lt_clientid, 8);
	READ32(lockt->lt_owner.len);
	READ_BUF(lockt->lt_owner.len);
	READMEM(lockt->lt_owner.data, lockt->lt_owner.len);

	if (argp->minorversion && !zero_clientid(&lockt->lt_clientid))
		return nfserr_inval;
	DECODE_TAIL;
}

static __be32
nfsd4_decode_locku(struct nfsd4_compoundargs *argp, struct nfsd4_locku *locku)
{
	DECODE_HEAD;

	locku->lu_stateowner = NULL;
	READ_BUF(8);
	READ32(locku->lu_type);
	if ((locku->lu_type < NFS4_READ_LT) || (locku->lu_type > NFS4_WRITEW_LT))
		goto xdr_error;
	READ32(locku->lu_seqid);
	status = nfsd4_decode_stateid(argp, &locku->lu_stateid);
	if (status)
		return status;
	READ_BUF(16);
	READ64(locku->lu_offset);
	READ64(locku->lu_length);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_lookup(struct nfsd4_compoundargs *argp, struct nfsd4_lookup *lookup)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(lookup->lo_len);
	READ_BUF(lookup->lo_len);
	SAVEMEM(lookup->lo_name, lookup->lo_len);
	if ((status = check_filename(lookup->lo_name, lookup->lo_len, nfserr_noent)))
		return status;

	DECODE_TAIL;
}

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

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

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

	/* owner, open_flag */
	READ_BUF(open->op_owner.len + 4);
	SAVEMEM(open->op_owner.data, open->op_owner.len);
	READ32(open->op_create);
	switch (open->op_create) {
	case NFS4_OPEN_NOCREATE:
		break;
	case NFS4_OPEN_CREATE:
		READ_BUF(4);
		READ32(open->op_createmode);
		switch (open->op_createmode) {
		case NFS4_CREATE_UNCHECKED:
		case NFS4_CREATE_GUARDED:
			status = nfsd4_decode_fattr(argp, open->op_bmval,
				&open->op_iattr, &open->op_acl);
			if (status)
				goto out;
			break;
		case NFS4_CREATE_EXCLUSIVE:
			READ_BUF(8);
			COPYMEM(open->op_verf.data, 8);
			break;
		case NFS4_CREATE_EXCLUSIVE4_1:
			if (argp->minorversion < 1)
				goto xdr_error;
			READ_BUF(8);
			COPYMEM(open->op_verf.data, 8);
			status = nfsd4_decode_fattr(argp, open->op_bmval,
				&open->op_iattr, &open->op_acl);
			if (status)
				goto out;
			break;
		default:
			goto xdr_error;
		}
		break;
	default:
		goto xdr_error;
	}

	/* open_claim */
	READ_BUF(4);
	READ32(open->op_claim_type);
	switch (open->op_claim_type) {
	case NFS4_OPEN_CLAIM_NULL:
	case NFS4_OPEN_CLAIM_DELEGATE_PREV:
		READ_BUF(4);
		READ32(open->op_fname.len);
		READ_BUF(open->op_fname.len);
		SAVEMEM(open->op_fname.data, open->op_fname.len);
		if ((status = check_filename(open->op_fname.data, open->op_fname.len, nfserr_inval)))
			return status;
		break;
	case NFS4_OPEN_CLAIM_PREVIOUS:
		READ_BUF(4);
		READ32(open->op_delegate_type);
		break;
	case NFS4_OPEN_CLAIM_DELEGATE_CUR:
		status = nfsd4_decode_stateid(argp, &open->op_delegate_stateid);
		if (status)
			return status;
		READ_BUF(4);
		READ32(open->op_fname.len);
		READ_BUF(open->op_fname.len);
		SAVEMEM(open->op_fname.data, open->op_fname.len);
		if ((status = check_filename(open->op_fname.data, open->op_fname.len, nfserr_inval)))
			return status;
		break;
	default:
		goto xdr_error;
	}

	DECODE_TAIL;
}

static __be32
nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_open_confirm *open_conf)
{
	DECODE_HEAD;
		    
	open_conf->oc_stateowner = NULL;
	status = nfsd4_decode_stateid(argp, &open_conf->oc_req_stateid);
	if (status)
		return status;
	READ_BUF(4);
	READ32(open_conf->oc_seqid);
						        
	DECODE_TAIL;
}

static __be32
nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
{
	DECODE_HEAD;
		    
	open_down->od_stateowner = NULL;
	status = nfsd4_decode_stateid(argp, &open_down->od_stateid);
	if (status)
		return status;
	READ_BUF(12);
	READ32(open_down->od_seqid);
	READ32(open_down->od_share_access);
	READ32(open_down->od_share_deny);
						        
	DECODE_TAIL;
}

static __be32
nfsd4_decode_putfh(struct nfsd4_compoundargs *argp, struct nfsd4_putfh *putfh)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(putfh->pf_fhlen);
	if (putfh->pf_fhlen > NFS4_FHSIZE)
		goto xdr_error;
	READ_BUF(putfh->pf_fhlen);
	SAVEMEM(putfh->pf_fhval, putfh->pf_fhlen);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_read(struct nfsd4_compoundargs *argp, struct nfsd4_read *read)
{
	DECODE_HEAD;

	status = nfsd4_decode_stateid(argp, &read->rd_stateid);
	if (status)
		return status;
	READ_BUF(12);
	READ64(read->rd_offset);
	READ32(read->rd_length);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_readdir(struct nfsd4_compoundargs *argp, struct nfsd4_readdir *readdir)
{
	DECODE_HEAD;

	READ_BUF(24);
	READ64(readdir->rd_cookie);
	COPYMEM(readdir->rd_verf.data, sizeof(readdir->rd_verf.data));
	READ32(readdir->rd_dircount);    /* just in case you needed a useless field... */
	READ32(readdir->rd_maxcount);
	if ((status = nfsd4_decode_bitmap(argp, readdir->rd_bmval)))
		goto out;

	DECODE_TAIL;
}

static __be32
nfsd4_decode_remove(struct nfsd4_compoundargs *argp, struct nfsd4_remove *remove)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(remove->rm_namelen);
	READ_BUF(remove->rm_namelen);
	SAVEMEM(remove->rm_name, remove->rm_namelen);
	if ((status = check_filename(remove->rm_name, remove->rm_namelen, nfserr_noent)))
		return status;

	DECODE_TAIL;
}

static __be32
nfsd4_decode_rename(struct nfsd4_compoundargs *argp, struct nfsd4_rename *rename)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(rename->rn_snamelen);
	READ_BUF(rename->rn_snamelen + 4);
	SAVEMEM(rename->rn_sname, rename->rn_snamelen);
	READ32(rename->rn_tnamelen);
	READ_BUF(rename->rn_tnamelen);
	SAVEMEM(rename->rn_tname, rename->rn_tnamelen);
	if ((status = check_filename(rename->rn_sname, rename->rn_snamelen, nfserr_noent)))
		return status;
	if ((status = check_filename(rename->rn_tname, rename->rn_tnamelen, nfserr_inval)))
		return status;

	DECODE_TAIL;
}

static __be32
nfsd4_decode_renew(struct nfsd4_compoundargs *argp, clientid_t *clientid)
{
	DECODE_HEAD;

	READ_BUF(sizeof(clientid_t));
	COPYMEM(clientid, sizeof(clientid_t));

	DECODE_TAIL;
}

static __be32
nfsd4_decode_secinfo(struct nfsd4_compoundargs *argp,
		     struct nfsd4_secinfo *secinfo)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(secinfo->si_namelen);
	READ_BUF(secinfo->si_namelen);
	SAVEMEM(secinfo->si_name, secinfo->si_namelen);
	status = check_filename(secinfo->si_name, secinfo->si_namelen,
								nfserr_noent);
	if (status)
		return status;
	DECODE_TAIL;
}

static __be32
nfsd4_decode_secinfo_no_name(struct nfsd4_compoundargs *argp,
		     struct nfsd4_secinfo_no_name *sin)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(sin->sin_style);
	DECODE_TAIL;
}

static __be32
nfsd4_decode_setattr(struct nfsd4_compoundargs *argp, struct nfsd4_setattr *setattr)
{
	__be32 status;

	status = nfsd4_decode_stateid(argp, &setattr->sa_stateid);
	if (status)
		return status;
	return nfsd4_decode_fattr(argp, setattr->sa_bmval, &setattr->sa_iattr,
				  &setattr->sa_acl);
}

static __be32
nfsd4_decode_setclientid(struct nfsd4_compoundargs *argp, struct nfsd4_setclientid *setclientid)
{
	DECODE_HEAD;

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

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

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

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

	DECODE_TAIL;
}

static __be32
nfsd4_decode_setclientid_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_setclientid_confirm *scd_c)
{
	DECODE_HEAD;

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

	DECODE_TAIL;
}

/* Also used for NVERIFY */
static __be32
nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify)
{
#if 0
	struct nfsd4_compoundargs save = {
		.p = argp->p,
		.end = argp->end,
		.rqstp = argp->rqstp,
	};
	u32             ve_bmval[2];
	struct iattr    ve_iattr;           /* request */
	struct nfs4_acl *ve_acl;            /* request */
#endif
	DECODE_HEAD;

	if ((status = nfsd4_decode_bitmap(argp, verify->ve_bmval)))
		goto out;

	/* For convenience's sake, we compare raw xdr'd attributes in
	 * nfsd4_proc_verify; however we still decode here just to return
	 * correct error in case of bad xdr. */
#if 0
	status = nfsd4_decode_fattr(ve_bmval, &ve_iattr, &ve_acl);
	if (status == nfserr_inval) {
		status = nfserrno(status);
		goto out;
	}
#endif
	READ_BUF(4);
	READ32(verify->ve_attrlen);
	READ_BUF(verify->ve_attrlen);
	SAVEMEM(verify->ve_attrval, verify->ve_attrlen);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
{
	int avail;
	int v;
	int len;
	DECODE_HEAD;

	status = nfsd4_decode_stateid(argp, &write->wr_stateid);
	if (status)
		return status;
	READ_BUF(16);
	READ64(write->wr_offset);
	READ32(write->wr_stable_how);
	if (write->wr_stable_how > 2)
		goto xdr_error;
	READ32(write->wr_buflen);

	/* Sorry .. no magic macros for this.. *
	 * READ_BUF(write->wr_buflen);
	 * SAVEMEM(write->wr_buf, write->wr_buflen);
	 */
	avail = (char*)argp->end - (char*)argp->p;
	if (avail + argp->pagelen < write->wr_buflen) {
		dprintk("NFSD: xdr error (%s:%d)\n",
				__FILE__, __LINE__);
		goto xdr_error;
	}
	argp->rqstp->rq_vec[0].iov_base = p;
	argp->rqstp->rq_vec[0].iov_len = avail;
	v = 0;
	len = write->wr_buflen;
	while (len > argp->rqstp->rq_vec[v].iov_len) {
		len -= argp->rqstp->rq_vec[v].iov_len;
		v++;
		argp->rqstp->rq_vec[v].iov_base = page_address(argp->pagelist[0]);
		argp->pagelist++;
		if (argp->pagelen >= PAGE_SIZE) {
			argp->rqstp->rq_vec[v].iov_len = PAGE_SIZE;
			argp->pagelen -= PAGE_SIZE;
		} else {
			argp->rqstp->rq_vec[v].iov_len = argp->pagelen;
			argp->pagelen -= len;
		}
	}
	argp->end = (__be32*) (argp->rqstp->rq_vec[v].iov_base + argp->rqstp->rq_vec[v].iov_len);
	argp->p = (__be32*)  (argp->rqstp->rq_vec[v].iov_base + (XDR_QUADLEN(len) << 2));
	argp->rqstp->rq_vec[v].iov_len = len;
	write->wr_vlen = v+1;

	DECODE_TAIL;
}

static __be32
nfsd4_decode_release_lockowner(struct nfsd4_compoundargs *argp, struct nfsd4_release_lockowner *rlockowner)
{
	DECODE_HEAD;

	READ_BUF(12);
	COPYMEM(&rlockowner->rl_clientid, sizeof(clientid_t));
	READ32(rlockowner->rl_owner.len);
	READ_BUF(rlockowner->rl_owner.len);
	READMEM(rlockowner->rl_owner.data, rlockowner->rl_owner.len);

	if (argp->minorversion && !zero_clientid(&rlockowner->rl_clientid))
		return nfserr_inval;
	DECODE_TAIL;
}

static __be32
nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
			 struct nfsd4_exchange_id *exid)
{
	int dummy, tmp;
	DECODE_HEAD;

	READ_BUF(NFS4_VERIFIER_SIZE);
	COPYMEM(exid->verifier.data, NFS4_VERIFIER_SIZE);

	READ_BUF(4);
	READ32(exid->clname.len);

	READ_BUF(exid->clname.len);
	SAVEMEM(exid->clname.data, exid->clname.len);

	READ_BUF(4);
	READ32(exid->flags);

	/* Ignore state_protect4_a */
	READ_BUF(4);
	READ32(exid->spa_how);
	switch (exid->spa_how) {
	case SP4_NONE:
		break;
	case SP4_MACH_CRED:
		/* spo_must_enforce */
		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy * 4);
		p += dummy;

		/* spo_must_allow */
		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy * 4);
		p += dummy;
		break;
	case SP4_SSV:
		/* ssp_ops */
		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy * 4);
		p += dummy;

		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy * 4);
		p += dummy;

		/* ssp_hash_algs<> */
		READ_BUF(4);
		READ32(tmp);
		while (tmp--) {
			READ_BUF(4);
			READ32(dummy);
			READ_BUF(dummy);
			p += XDR_QUADLEN(dummy);
		}

		/* ssp_encr_algs<> */
		READ_BUF(4);
		READ32(tmp);
		while (tmp--) {
			READ_BUF(4);
			READ32(dummy);
			READ_BUF(dummy);
			p += XDR_QUADLEN(dummy);
		}

		/* ssp_window and ssp_num_gss_handles */
		READ_BUF(8);
		READ32(dummy);
		READ32(dummy);
		break;
	default:
		goto xdr_error;
	}

	/* Ignore Implementation ID */
	READ_BUF(4);    /* nfs_impl_id4 array length */
	READ32(dummy);

	if (dummy > 1)
		goto xdr_error;

	if (dummy == 1) {
		/* nii_domain */
		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy);
		p += XDR_QUADLEN(dummy);

		/* nii_name */
		READ_BUF(4);
		READ32(dummy);
		READ_BUF(dummy);
		p += XDR_QUADLEN(dummy);

		/* nii_date */
		READ_BUF(12);
		p += 3;
	}
	DECODE_TAIL;
}

static __be32
nfsd4_decode_create_session(struct nfsd4_compoundargs *argp,
			    struct nfsd4_create_session *sess)
{
	DECODE_HEAD;

	u32 dummy;
	char *machine_name;
	int i;
	int nr_secflavs;

	READ_BUF(16);
	COPYMEM(&sess->clientid, 8);
	READ32(sess->seqid);
	READ32(sess->flags);

	/* Fore channel attrs */
	READ_BUF(28);
	READ32(dummy); /* headerpadsz is always 0 */
	READ32(sess->fore_channel.maxreq_sz);
	READ32(sess->fore_channel.maxresp_sz);
	READ32(sess->fore_channel.maxresp_cached);
	READ32(sess->fore_channel.maxops);
	READ32(sess->fore_channel.maxreqs);
	READ32(sess->fore_channel.nr_rdma_attrs);
	if (sess->fore_channel.nr_rdma_attrs == 1) {
		READ_BUF(4);
		READ32(sess->fore_channel.rdma_attrs);
	} else if (sess->fore_channel.nr_rdma_attrs > 1) {
		dprintk("Too many fore channel attr bitmaps!\n");
		goto xdr_error;
	}

	/* Back channel attrs */
	READ_BUF(28);
	READ32(dummy); /* headerpadsz is always 0 */
	READ32(sess->back_channel.maxreq_sz);
	READ32(sess->back_channel.maxresp_sz);
	READ32(sess->back_channel.maxresp_cached);
	READ32(sess->back_channel.maxops);
	READ32(sess->back_channel.maxreqs);
	READ32(sess->back_channel.nr_rdma_attrs);
	if (sess->back_channel.nr_rdma_attrs == 1) {
		READ_BUF(4);
		READ32(sess->back_channel.rdma_attrs);
	} else if (sess->back_channel.nr_rdma_attrs > 1) {
		dprintk("Too many back channel attr bitmaps!\n");
		goto xdr_error;
	}

	READ_BUF(8);
	READ32(sess->callback_prog);

	/* callback_sec_params4 */
	READ32(nr_secflavs);
	for (i = 0; i < nr_secflavs; ++i) {
		READ_BUF(4);
		READ32(dummy);
		switch (dummy) {
		case RPC_AUTH_NULL:
			/* Nothing to read */
			break;
		case RPC_AUTH_UNIX:
			READ_BUF(8);
			/* stamp */
			READ32(dummy);

			/* machine name */
			READ32(dummy);
			READ_BUF(dummy);
			SAVEMEM(machine_name, dummy);

			/* uid, gid */
			READ_BUF(8);
			READ32(sess->uid);
			READ32(sess->gid);

			/* more gids */
			READ_BUF(4);
			READ32(dummy);
			READ_BUF(dummy * 4);
			break;
		case RPC_AUTH_GSS:
			dprintk("RPC_AUTH_GSS callback secflavor "
				"not supported!\n");
			READ_BUF(8);
			/* gcbp_service */
			READ32(dummy);
			/* gcbp_handle_from_server */
			READ32(dummy);
			READ_BUF(dummy);
			p += XDR_QUADLEN(dummy);
			/* gcbp_handle_from_client */
			READ_BUF(4);
			READ32(dummy);
			READ_BUF(dummy);
			break;
		default:
			dprintk("Illegal callback secflavor\n");
			return nfserr_inval;
		}
	}
	DECODE_TAIL;
}

static __be32
nfsd4_decode_destroy_session(struct nfsd4_compoundargs *argp,
			     struct nfsd4_destroy_session *destroy_session)
{
	DECODE_HEAD;
	READ_BUF(NFS4_MAX_SESSIONID_LEN);
	COPYMEM(destroy_session->sessionid.data, NFS4_MAX_SESSIONID_LEN);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
		      struct nfsd4_sequence *seq)
{
	DECODE_HEAD;

	READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
	COPYMEM(seq->sessionid.data, NFS4_MAX_SESSIONID_LEN);
	READ32(seq->seqid);
	READ32(seq->slotid);
	READ32(seq->maxslots);
	READ32(seq->cachethis);

	DECODE_TAIL;
}

static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp, struct nfsd4_reclaim_complete *rc)
{
	DECODE_HEAD;

	READ_BUF(4);
	READ32(rc->rca_one_fs);

	DECODE_TAIL;
}

static __be32
nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
{
	return nfs_ok;
}

static __be32
nfsd4_decode_notsupp(struct nfsd4_compoundargs *argp, void *p)
{
	return nfserr_notsupp;
}

typedef __be32(*nfsd4_dec)(struct nfsd4_compoundargs *argp, void *);

static nfsd4_dec nfsd4_dec_ops[] = {
	[OP_ACCESS]		= (nfsd4_dec)nfsd4_decode_access,
	[OP_CLOSE]		= (nfsd4_dec)nfsd4_decode_close,
	[OP_COMMIT]		= (nfsd4_dec)nfsd4_decode_commit,
	[OP_CREATE]		= (nfsd4_dec)nfsd4_decode_create,
	[OP_DELEGPURGE]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_DELEGRETURN]	= (nfsd4_dec)nfsd4_decode_delegreturn,
	[OP_GETATTR]		= (nfsd4_dec)nfsd4_decode_getattr,
	[OP_GETFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_LINK]		= (nfsd4_dec)nfsd4_decode_link,
	[OP_LOCK]		= (nfsd4_dec)nfsd4_decode_lock,
	[OP_LOCKT]		= (nfsd4_dec)nfsd4_decode_lockt,
	[OP_LOCKU]		= (nfsd4_dec)nfsd4_decode_locku,
	[OP_LOOKUP]		= (nfsd4_dec)nfsd4_decode_lookup,
	[OP_LOOKUPP]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_NVERIFY]		= (nfsd4_dec)nfsd4_decode_verify,
	[OP_OPEN]		= (nfsd4_dec)nfsd4_decode_open,
	[OP_OPENATTR]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_OPEN_CONFIRM]	= (nfsd4_dec)nfsd4_decode_open_confirm,
	[OP_OPEN_DOWNGRADE]	= (nfsd4_dec)nfsd4_decode_open_downgrade,
	[OP_PUTFH]		= (nfsd4_dec)nfsd4_decode_putfh,
	[OP_PUTPUBFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_PUTROOTFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_READ]		= (nfsd4_dec)nfsd4_decode_read,
	[OP_READDIR]		= (nfsd4_dec)nfsd4_decode_readdir,
	[OP_READLINK]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_REMOVE]		= (nfsd4_dec)nfsd4_decode_remove,
	[OP_RENAME]		= (nfsd4_dec)nfsd4_decode_rename,
	[OP_RENEW]		= (nfsd4_dec)nfsd4_decode_renew,
	[OP_RESTOREFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_SAVEFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_SECINFO]		= (nfsd4_dec)nfsd4_decode_secinfo,
	[OP_SETATTR]		= (nfsd4_dec)nfsd4_decode_setattr,
	[OP_SETCLIENTID]	= (nfsd4_dec)nfsd4_decode_setclientid,
	[OP_SETCLIENTID_CONFIRM] = (nfsd4_dec)nfsd4_decode_setclientid_confirm,
	[OP_VERIFY]		= (nfsd4_dec)nfsd4_decode_verify,
	[OP_WRITE]		= (nfsd4_dec)nfsd4_decode_write,
	[OP_RELEASE_LOCKOWNER]	= (nfsd4_dec)nfsd4_decode_release_lockowner,
};

static nfsd4_dec nfsd41_dec_ops[] = {
	[OP_ACCESS]		= (nfsd4_dec)nfsd4_decode_access,
	[OP_CLOSE]		= (nfsd4_dec)nfsd4_decode_close,
	[OP_COMMIT]		= (nfsd4_dec)nfsd4_decode_commit,
	[OP_CREATE]		= (nfsd4_dec)nfsd4_decode_create,
	[OP_DELEGPURGE]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_DELEGRETURN]	= (nfsd4_dec)nfsd4_decode_delegreturn,
	[OP_GETATTR]		= (nfsd4_dec)nfsd4_decode_getattr,
	[OP_GETFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_LINK]		= (nfsd4_dec)nfsd4_decode_link,
	[OP_LOCK]		= (nfsd4_dec)nfsd4_decode_lock,
	[OP_LOCKT]		= (nfsd4_dec)nfsd4_decode_lockt,
	[OP_LOCKU]		= (nfsd4_dec)nfsd4_decode_locku,
	[OP_LOOKUP]		= (nfsd4_dec)nfsd4_decode_lookup,
	[OP_LOOKUPP]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_NVERIFY]		= (nfsd4_dec)nfsd4_decode_verify,
	[OP_OPEN]		= (nfsd4_dec)nfsd4_decode_open,
	[OP_OPENATTR]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_OPEN_CONFIRM]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_OPEN_DOWNGRADE]	= (nfsd4_dec)nfsd4_decode_open_downgrade,
	[OP_PUTFH]		= (nfsd4_dec)nfsd4_decode_putfh,
	[OP_PUTPUBFH]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_PUTROOTFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_READ]		= (nfsd4_dec)nfsd4_decode_read,
	[OP_READDIR]		= (nfsd4_dec)nfsd4_decode_readdir,
	[OP_READLINK]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_REMOVE]		= (nfsd4_dec)nfsd4_decode_remove,
	[OP_RENAME]		= (nfsd4_dec)nfsd4_decode_rename,
	[OP_RENEW]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_RESTOREFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_SAVEFH]		= (nfsd4_dec)nfsd4_decode_noop,
	[OP_SECINFO]		= (nfsd4_dec)nfsd4_decode_secinfo,
	[OP_SETATTR]		= (nfsd4_dec)nfsd4_decode_setattr,
	[OP_SETCLIENTID]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_SETCLIENTID_CONFIRM]= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_VERIFY]		= (nfsd4_dec)nfsd4_decode_verify,
	[OP_WRITE]		= (nfsd4_dec)nfsd4_decode_write,
	[OP_RELEASE_LOCKOWNER]	= (nfsd4_dec)nfsd4_decode_notsupp,

	/* new operations for NFSv4.1 */
	[OP_BACKCHANNEL_CTL]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_BIND_CONN_TO_SESSION]= (nfsd4_dec)nfsd4_decode_bind_conn_to_session,
	[OP_EXCHANGE_ID]	= (nfsd4_dec)nfsd4_decode_exchange_id,
	[OP_CREATE_SESSION]	= (nfsd4_dec)nfsd4_decode_create_session,
	[OP_DESTROY_SESSION]	= (nfsd4_dec)nfsd4_decode_destroy_session,
	[OP_FREE_STATEID]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_GET_DIR_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_GETDEVICEINFO]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_GETDEVICELIST]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_LAYOUTCOMMIT]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_LAYOUTGET]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_LAYOUTRETURN]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_SECINFO_NO_NAME]	= (nfsd4_dec)nfsd4_decode_secinfo_no_name,
	[OP_SEQUENCE]		= (nfsd4_dec)nfsd4_decode_sequence,
	[OP_SET_SSV]		= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_TEST_STATEID]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_WANT_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_DESTROY_CLIENTID]	= (nfsd4_dec)nfsd4_decode_notsupp,
	[OP_RECLAIM_COMPLETE]	= (nfsd4_dec)nfsd4_decode_reclaim_complete,
};

struct nfsd4_minorversion_ops {
	nfsd4_dec *decoders;
	int nops;
};

static struct nfsd4_minorversion_ops nfsd4_minorversion[] = {
	[0] = { nfsd4_dec_ops, ARRAY_SIZE(nfsd4_dec_ops) },
	[1] = { nfsd41_dec_ops, ARRAY_SIZE(nfsd41_dec_ops) },
};

static __be32
nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
{
	DECODE_HEAD;
	struct nfsd4_op *op;
	struct nfsd4_minorversion_ops *ops;
	int i;

	/*
	 * XXX: According to spec, we should check the tag
	 * for UTF-8 compliance.  I'm postponing this for
	 * now because it seems that some clients do use
	 * binary tags.
	 */
	READ_BUF(4);
	READ32(argp->taglen);
	READ_BUF(argp->taglen + 8);
	SAVEMEM(argp->tag, argp->taglen);
	READ32(argp->minorversion);
	READ32(argp->opcnt);

	if (argp->taglen > NFSD4_MAX_TAGLEN)
		goto xdr_error;
	if (argp->opcnt > 100)
		goto xdr_error;

	if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
		argp->ops = kmalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
		if (!argp->ops) {
			argp->ops = argp->iops;
			dprintk("nfsd: couldn't allocate room for COMPOUND\n");
			goto xdr_error;
		}
	}

	if (argp->minorversion >= ARRAY_SIZE(nfsd4_minorversion))
		argp->opcnt = 0;

	ops = &nfsd4_minorversion[argp->minorversion];
	for (i = 0; i < argp->opcnt; i++) {
		op = &argp->ops[i];
		op->replay = NULL;

		/*
		 * We can't use READ_BUF() here because we need to handle
		 * a missing opcode as an OP_WRITE + 1. So we need to check
		 * to see if we're truly at the end of our buffer or if there
		 * is another page we need to flip to.
		 */

		if (argp->p == argp->end) {
			if (argp->pagelen < 4) {
				/* There isn't an opcode still on the wire */
				op->opnum = OP_WRITE + 1;
				op->status = nfserr_bad_xdr;
				argp->opcnt = i+1;
				break;
			}

			/*
			 * False alarm. We just hit a page boundary, but there
			 * is still data available.  Move pointer across page
			 * boundary.  *snip from READ_BUF*
			 */
			argp->p = page_address(argp->pagelist[0]);
			argp->pagelist++;
			if (argp->pagelen < PAGE_SIZE) {
				argp->end = argp->p + (argp->pagelen>>2);
				argp->pagelen = 0;
			} else {
				argp->end = argp->p + (PAGE_SIZE>>2);
				argp->pagelen -= PAGE_SIZE;
			}
		}
		op->opnum = ntohl(*argp->p++);

		if (op->opnum >= FIRST_NFS4_OP && op->opnum <= LAST_NFS4_OP)
			op->status = ops->decoders[op->opnum](argp, &op->u);
		else {
			op->opnum = OP_ILLEGAL;
			op->status = nfserr_op_illegal;
		}

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

	DECODE_TAIL;
}

#define WRITE32(n)               *p++ = htonl(n)
#define WRITE64(n)               do {				\
	*p++ = htonl((u32)((n) >> 32));				\
	*p++ = htonl((u32)(n));					\
} while (0)
#define WRITEMEM(ptr,nbytes)     do { if (nbytes > 0) {		\
	*(p + XDR_QUADLEN(nbytes) -1) = 0;                      \
	memcpy(p, ptr, nbytes);					\
	p += XDR_QUADLEN(nbytes);				\
}} while (0)

static void write32(__be32 **p, u32 n)
{
	*(*p)++ = n;
}

static void write64(__be32 **p, u64 n)
{
	write32(p, (u32)(n >> 32));
	write32(p, (u32)n);
}

static void write_change(__be32 **p, struct kstat *stat, struct inode *inode)
{
	if (IS_I_VERSION(inode)) {
		write64(p, inode->i_version);
	} else {
		write32(p, stat->ctime.tv_sec);
		write32(p, stat->ctime.tv_nsec);
	}
}

static void write_cinfo(__be32 **p, struct nfsd4_change_info *c)
{
	write32(p, c->atomic);
	if (c->change_supported) {
		write64(p, c->before_change);
		write64(p, c->after_change);
	} else {
		write32(p, c->before_ctime_sec);
		write32(p, c->before_ctime_nsec);
		write32(p, c->after_ctime_sec);
		write32(p, c->after_ctime_nsec);
	}
}

#define RESERVE_SPACE(nbytes)	do {				\
	p = resp->p;						\
	BUG_ON(p + XDR_QUADLEN(nbytes) > resp->end);		\
} while (0)
#define ADJUST_ARGS()		resp->p = p

/*
 * Header routine to setup seqid operation replay cache
 */
#define ENCODE_SEQID_OP_HEAD					\
	__be32 *save;						\
								\
	save = resp->p;

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

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

/* Encode as an array of strings the string given with components
 * separated @sep.
 */
static __be32 nfsd4_encode_components(char sep, char *components,
				   __be32 **pp, int *buflen)
{
	__be32 *p = *pp;
	__be32 *countp = p;
	int strlen, count=0;
	char *str, *end;

	dprintk("nfsd4_encode_components(%s)\n", components);
	if ((*buflen -= 4) < 0)
		return nfserr_resource;
	WRITE32(0); /* We will fill this in with @count later */
	end = str = components;
	while (*end) {
		for (; *end && (*end != sep); end++)
			; /* Point to end of component */
		strlen = end - str;
		if (strlen) {
			if ((*buflen -= ((XDR_QUADLEN(strlen) << 2) + 4)) < 0)
				return nfserr_resource;
			WRITE32(strlen);
			WRITEMEM(str, strlen);
			count++;
		}
		else
			end++;
		str = end;
	}
	*pp = p;
	p = countp;
	WRITE32(count);
	return 0;
}

/*
 * encode a location element of a fs_locations structure
 */
static __be32 nfsd4_encode_fs_location4(struct nfsd4_fs_location *location,
				    __be32 **pp, int *buflen)
{
	__be32 status;
	__be32 *p = *pp;

	status = nfsd4_encode_components(':', location->hosts, &p, buflen);
	if (status)
		return status;
	status = nfsd4_encode_components('/', location->path, &p, buflen);
	if (status)
		return status;
	*pp = p;
	return 0;
}

/*
 * Return the path to an export point in the pseudo filesystem namespace
 * Returned string is safe to use as long as the caller holds a reference
 * to @exp.
 */
static char *nfsd4_path(struct svc_rqst *rqstp, struct svc_export *exp, __be32 *stat)
{
	struct svc_fh tmp_fh;
	char *path = NULL, *rootpath;
	size_t rootlen;

	fh_init(&tmp_fh, NFS4_FHSIZE);
	*stat = exp_pseudoroot(rqstp, &tmp_fh);
	if (*stat)
		return NULL;
	rootpath = tmp_fh.fh_export->ex_pathname;

	path = exp->ex_pathname;

	rootlen = strlen(rootpath);
	if (strncmp(path, rootpath, rootlen)) {
		dprintk("nfsd: fs_locations failed;"
			"%s is not contained in %s\n", path, rootpath);
		*stat = nfserr_notsupp;
		path = NULL;
		goto out;
	}
	path += rootlen;
out:
	fh_put(&tmp_fh);
	return path;
}

/*
 *  encode a fs_locations structure
 */
static __be32 nfsd4_encode_fs_locations(struct svc_rqst *rqstp,
				     struct svc_export *exp,
				     __be32 **pp, int *buflen)
{
	__be32 status;
	int i;
	__be32 *p = *pp;
	struct nfsd4_fs_locations *fslocs = &exp->ex_fslocs;
	char *root = nfsd4_path(rqstp, exp, &status);

	if (status)
		return status;
	status = nfsd4_encode_components('/', root, &p, buflen);
	if (status)
		return status;
	if ((*buflen -= 4) < 0)
		return nfserr_resource;
	WRITE32(fslocs->locations_count);
	for (i=0; i<fslocs->locations_count; i++) {
		status = nfsd4_encode_fs_location4(&fslocs->locations[i],
						   &p, buflen);
		if (status)
			return status;
	}
	*pp = p;
	return 0;
}

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

static __be32
nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
			__be32 **p, int *buflen)
{
	int status;

	if (*buflen < (XDR_QUADLEN(IDMAP_NAMESZ) << 2) + 4)
		return nfserr_resource;
	if (whotype != NFS4_ACL_WHO_NAMED)
		status = nfs4_acl_write_who(whotype, (u8 *)(*p + 1));
	else if (group)
		status = nfsd_map_gid_to_name(rqstp, id, (u8 *)(*p + 1));
	else
		status = nfsd_map_uid_to_name(rqstp, id, (u8 *)(*p + 1));
	if (status < 0)
		return nfserrno(status);
	*p = xdr_encode_opaque(*p, NULL, status);
	*buflen -= (XDR_QUADLEN(status) << 2) + 4;
	BUG_ON(*buflen < 0);
	return 0;
}

static inline __be32
nfsd4_encode_user(struct svc_rqst *rqstp, uid_t uid, __be32 **p, int *buflen)
{
	return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, uid, 0, p, buflen);
}

static inline __be32
nfsd4_encode_group(struct svc_rqst *rqstp, uid_t gid, __be32 **p, int *buflen)
{
	return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, gid, 1, p, buflen);
}

static inline __be32
nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
		__be32 **p, int *buflen)
{
	return nfsd4_encode_name(rqstp, whotype, id, group, p, buflen);
}

#define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
			      FATTR4_WORD0_RDATTR_ERROR)
#define WORD1_ABSENT_FS_ATTRS FATTR4_WORD1_MOUNTED_ON_FILEID

static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *rdattr_err)
{
	/* As per referral draft:  */
	if (*bmval0 & ~WORD0_ABSENT_FS_ATTRS ||
	    *bmval1 & ~WORD1_ABSENT_FS_ATTRS) {
		if (*bmval0 & FATTR4_WORD0_RDATTR_ERROR ||
	            *bmval0 & FATTR4_WORD0_FS_LOCATIONS)
			*rdattr_err = NFSERR_MOVED;
		else
			return nfserr_moved;
	}
	*bmval0 &= WORD0_ABSENT_FS_ATTRS;
	*bmval1 &= WORD1_ABSENT_FS_ATTRS;
	return 0;
}

/*
 * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
 * ourselves.
 *
 * @countp is the buffer size in _words_; upon successful return this becomes
 * replaced with the number of words written.
 */
__be32
nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
		struct dentry *dentry, __be32 *buffer, int *countp, u32 *bmval,
		struct svc_rqst *rqstp, int ignore_crossmnt)
{
	u32 bmval0 = bmval[0];
	u32 bmval1 = bmval[1];
	u32 bmval2 = bmval[2];
	struct kstat stat;
	struct svc_fh tempfh;
	struct kstatfs statfs;
	int buflen = *countp << 2;
	__be32 *attrlenp;
	u32 dummy;
	u64 dummy64;
	u32 rdattr_err = 0;
	__be32 *p = buffer;
	__be32 status;
	int err;
	int aclsupport = 0;
	struct nfs4_acl *acl = NULL;
	struct nfsd4_compoundres *resp = rqstp->rq_resp;
	u32 minorversion = resp->cstate.minorversion;
	struct path path = {
		.mnt	= exp->ex_path.mnt,
		.dentry	= dentry,
	};

	BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
	BUG_ON(bmval0 & ~nfsd_suppattrs0(minorversion));
	BUG_ON(bmval1 & ~nfsd_suppattrs1(minorversion));
	BUG_ON(bmval2 & ~nfsd_suppattrs2(minorversion));

	if (exp->ex_fslocs.migrated) {
		BUG_ON(bmval[2]);
		status = fattr_handle_absent_fs(&bmval0, &bmval1, &rdattr_err);
		if (status)
			goto out;
	}

	err = vfs_getattr(exp->ex_path.mnt, dentry, &stat);
	if (err)
		goto out_nfserr;
	if ((bmval0 & (FATTR4_WORD0_FILES_FREE | FATTR4_WORD0_FILES_TOTAL |
			FATTR4_WORD0_MAXNAME)) ||
	    (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
		       FATTR4_WORD1_SPACE_TOTAL))) {
		err = vfs_statfs(&path, &statfs);
		if (err)
			goto out_nfserr;
	}
	if ((bmval0 & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) && !fhp) {
		fh_init(&tempfh, NFS4_FHSIZE);
		status = fh_compose(&tempfh, exp, dentry, NULL);
		if (status)
			goto out;
		fhp = &tempfh;
	}
	if (bmval0 & (FATTR4_WORD0_ACL | FATTR4_WORD0_ACLSUPPORT
			| FATTR4_WORD0_SUPPORTED_ATTRS)) {
		err = nfsd4_get_nfs4_acl(rqstp, dentry, &acl);
		aclsupport = (err == 0);
		if (bmval0 & FATTR4_WORD0_ACL) {
			if (err == -EOPNOTSUPP)
				bmval0 &= ~FATTR4_WORD0_ACL;
			else if (err == -EINVAL) {
				status = nfserr_attrnotsupp;
				goto out;
			} else if (err != 0)
				goto out_nfserr;
		}
	}

	if (bmval2) {
		if ((buflen -= 16) < 0)
			goto out_resource;
		WRITE32(3);
		WRITE32(bmval0);
		WRITE32(bmval1);
		WRITE32(bmval2);
	} else if (bmval1) {
		if ((buflen -= 12) < 0)
			goto out_resource;
		WRITE32(2);
		WRITE32(bmval0);
		WRITE32(bmval1);
	} else {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE32(1);
		WRITE32(bmval0);
	}
	attrlenp = p++;                /* to be backfilled later */

	if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
		u32 word0 = nfsd_suppattrs0(minorversion);
		u32 word1 = nfsd_suppattrs1(minorversion);
		u32 word2 = nfsd_suppattrs2(minorversion);

		if (!aclsupport)
			word0 &= ~FATTR4_WORD0_ACL;
		if (!word2) {
			if ((buflen -= 12) < 0)
				goto out_resource;
			WRITE32(2);
			WRITE32(word0);
			WRITE32(word1);
		} else {
			if ((buflen -= 16) < 0)
				goto out_resource;
			WRITE32(3);
			WRITE32(word0);
			WRITE32(word1);
			WRITE32(word2);
		}
	}
	if (bmval0 & FATTR4_WORD0_TYPE) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		dummy = nfs4_ftypes[(stat.mode & S_IFMT) >> 12];
		if (dummy == NF4BAD)
			goto out_serverfault;
		WRITE32(dummy);
	}
	if (bmval0 & FATTR4_WORD0_FH_EXPIRE_TYPE) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
			WRITE32(NFS4_FH_PERSISTENT);
		else
			WRITE32(NFS4_FH_PERSISTENT|NFS4_FH_VOL_RENAME);
	}
	if (bmval0 & FATTR4_WORD0_CHANGE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		write_change(&p, &stat, dentry->d_inode);
	}
	if (bmval0 & FATTR4_WORD0_SIZE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64(stat.size);
	}
	if (bmval0 & FATTR4_WORD0_LINK_SUPPORT) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_SYMLINK_SUPPORT) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_NAMED_ATTR) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(0);
	}
	if (bmval0 & FATTR4_WORD0_FSID) {
		if ((buflen -= 16) < 0)
			goto out_resource;
		if (exp->ex_fslocs.migrated) {
			WRITE64(NFS4_REFERRAL_FSID_MAJOR);
			WRITE64(NFS4_REFERRAL_FSID_MINOR);
		} else switch(fsid_source(fhp)) {
		case FSIDSOURCE_FSID:
			WRITE64((u64)exp->ex_fsid);
			WRITE64((u64)0);
			break;
		case FSIDSOURCE_DEV:
			WRITE32(0);
			WRITE32(MAJOR(stat.dev));
			WRITE32(0);
			WRITE32(MINOR(stat.dev));
			break;
		case FSIDSOURCE_UUID:
			WRITEMEM(exp->ex_uuid, 16);
			break;
		}
	}
	if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(0);
	}
	if (bmval0 & FATTR4_WORD0_LEASE_TIME) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(nfsd4_lease);
	}
	if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(rdattr_err);
	}
	if (bmval0 & FATTR4_WORD0_ACL) {
		struct nfs4_ace *ace;

		if (acl == NULL) {
			if ((buflen -= 4) < 0)
				goto out_resource;

			WRITE32(0);
			goto out_acl;
		}
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(acl->naces);

		for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
			if ((buflen -= 4*3) < 0)
				goto out_resource;
			WRITE32(ace->type);
			WRITE32(ace->flag);
			WRITE32(ace->access_mask & NFS4_ACE_MASK_ALL);
			status = nfsd4_encode_aclname(rqstp, ace->whotype,
				ace->who, ace->flag & NFS4_ACE_IDENTIFIER_GROUP,
				&p, &buflen);
			if (status == nfserr_resource)
				goto out_resource;
			if (status)
				goto out;
		}
	}
out_acl:
	if (bmval0 & FATTR4_WORD0_ACLSUPPORT) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(aclsupport ?
			ACL4_SUPPORT_ALLOW_ACL|ACL4_SUPPORT_DENY_ACL : 0);
	}
	if (bmval0 & FATTR4_WORD0_CANSETTIME) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_CHOWN_RESTRICTED) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_FILEHANDLE) {
		buflen -= (XDR_QUADLEN(fhp->fh_handle.fh_size) << 2) + 4;
		if (buflen < 0)
			goto out_resource;
		WRITE32(fhp->fh_handle.fh_size);
		WRITEMEM(&fhp->fh_handle.fh_base, fhp->fh_handle.fh_size);
	}
	if (bmval0 & FATTR4_WORD0_FILEID) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64(stat.ino);
	}
	if (bmval0 & FATTR4_WORD0_FILES_AVAIL) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64((u64) statfs.f_ffree);
	}
	if (bmval0 & FATTR4_WORD0_FILES_FREE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64((u64) statfs.f_ffree);
	}
	if (bmval0 & FATTR4_WORD0_FILES_TOTAL) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64((u64) statfs.f_files);
	}
	if (bmval0 & FATTR4_WORD0_FS_LOCATIONS) {
		status = nfsd4_encode_fs_locations(rqstp, exp, &p, &buflen);
		if (status == nfserr_resource)
			goto out_resource;
		if (status)
			goto out;
	}
	if (bmval0 & FATTR4_WORD0_HOMOGENEOUS) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval0 & FATTR4_WORD0_MAXFILESIZE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64(~(u64)0);
	}
	if (bmval0 & FATTR4_WORD0_MAXLINK) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(255);
	}
	if (bmval0 & FATTR4_WORD0_MAXNAME) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(statfs.f_namelen);
	}
	if (bmval0 & FATTR4_WORD0_MAXREAD) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64((u64) svc_max_payload(rqstp));
	}
	if (bmval0 & FATTR4_WORD0_MAXWRITE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE64((u64) svc_max_payload(rqstp));
	}
	if (bmval1 & FATTR4_WORD1_MODE) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(stat.mode & S_IALLUGO);
	}
	if (bmval1 & FATTR4_WORD1_NO_TRUNC) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(1);
	}
	if (bmval1 & FATTR4_WORD1_NUMLINKS) {
		if ((buflen -= 4) < 0)
			goto out_resource;
		WRITE32(stat.nlink);
	}
	if (bmval1 & FATTR4_WORD1_OWNER) {
		status = nfsd4_encode_user(rqstp, stat.uid, &p, &buflen);
		if (status == nfserr_resource)
			goto out_resource;
		if (status)
			goto out;
	}
	if (bmval1 & FATTR4_WORD1_OWNER_GROUP) {
		status = nfsd4_encode_group(rqstp, stat.gid, &p, &buflen);
		if (status == nfserr_resource)
			goto out_resource;
		if (status)
			goto out;
	}
	if (bmval1 & FATTR4_WORD1_RAWDEV) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		WRITE32((u32) MAJOR(stat.rdev));
		WRITE32((u32) MINOR(stat.rdev));
	}
	if (bmval1 & FATTR4_WORD1_SPACE_AVAIL) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		dummy64 = (u64)statfs.f_bavail * (u64)statfs.f_bsize;
		WRITE64(dummy64);
	}
	if (bmval1 & FATTR4_WORD1_SPACE_FREE) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		dummy64 = (u64)statfs.f_bfree * (u64)statfs.f_bsize;
		WRITE64(dummy64);
	}
	if (bmval1 & FATTR4_WORD1_SPACE_TOTAL) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		dummy64 = (u64)statfs.f_blocks * (u64)statfs.f_bsize;
		WRITE64(dummy64);
	}
	if (bmval1 & FATTR4_WORD1_SPACE_USED) {
		if ((buflen -= 8) < 0)
			goto out_resource;
		dummy64 = (u64)stat.blocks << 9;
		WRITE64(dummy64);
	}
	if (bmval1 & FATTR4_WORD1_TIME_ACCESS) {
		if ((buflen -= 12) < 0)
			goto out_resource;
		WRITE32(0);
		WRITE32(stat.atime.tv_sec);
		WRITE32(stat.atime.tv_nsec);
	}
	if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
		if ((buflen -= 12) < 0)
			goto out_resource;
		WRITE32(0);
		WRITE32(1);
		WRITE32(0);
	}
	if (bmval1 & FATTR4_WORD1_TIME_METADATA) {
		if ((buflen -= 12) < 0)
			goto out_resource;
		WRITE32(0);
		WRITE32(stat.ctime.tv_sec);
		WRITE32(stat.ctime.tv_nsec);
	}
	if (bmval1 & FATTR4_WORD1_TIME_MODIFY) {
		if ((buflen -= 12) < 0)
			goto out_resource;
		WRITE32(0);
		WRITE32(stat.mtime.tv_sec);
		WRITE32(stat.mtime.tv_nsec);
	}
	if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
		if ((buflen -= 8) < 0)
                	goto out_resource;
		/*
		 * Get parent's attributes if not ignoring crossmount
		 * and this is the root of a cross-mounted filesystem.
		 */
		if (ignore_crossmnt == 0 &&
		    dentry == exp->ex_path.mnt->mnt_root) {
			struct path path = exp->ex_path;
			path_get(&path);
			while (follow_up(&path)) {
				if (path.dentry != path.mnt->mnt_root)
					break;
			}
			err = vfs_getattr(path.mnt, path.dentry, &stat);
			path_put(&path);
			if (err)
				goto out_nfserr;
		}
		WRITE64(stat.ino);
	}
	if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
		WRITE32(3);
		WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD0);
		WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD1);
		WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD2);
	}

	*attrlenp = htonl((char *)p - (char *)attrlenp - 4);
	*countp = p - buffer;
	status = nfs_ok;

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

static inline int attributes_need_mount(u32 *bmval)
{
	if (bmval[0] & ~(FATTR4_WORD0_RDATTR_ERROR | FATTR4_WORD0_LEASE_TIME))
		return 1;
	if (bmval[1] & ~FATTR4_WORD1_MOUNTED_ON_FILEID)
		return 1;
	return 0;
}

static __be32
nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
		const char *name, int namlen, __be32 *p, int *buflen)
{
	struct svc_export *exp = cd->rd_fhp->fh_export;
	struct dentry *dentry;
	__be32 nfserr;
	int ignore_crossmnt = 0;

	dentry = lookup_one_len(name, cd->rd_fhp->fh_dentry, namlen);
	if (IS_ERR(dentry))
		return nfserrno(PTR_ERR(dentry));
	if (!dentry->d_inode) {
		/*
		 * nfsd_buffered_readdir drops the i_mutex between
		 * readdir and calling this callback, leaving a window
		 * where this directory entry could have gone away.
		 */
		dput(dentry);
		return nfserr_noent;
	}

	exp_get(exp);
	/*
	 * In the case of a mountpoint, the client may be asking for
	 * attributes that are only properties of the underlying filesystem
	 * as opposed to the cross-mounted file system. In such a case,
	 * we will not follow the cross mount and will fill the attribtutes
	 * directly from the mountpoint dentry.
	 */
	if (nfsd_mountpoint(dentry, exp)) {
		int err;

		if (!(exp->ex_flags & NFSEXP_V4ROOT)
				&& !attributes_need_mount(cd->rd_bmval)) {
			ignore_crossmnt = 1;
			goto out_encode;
		}
		/*
		 * Why the heck aren't we just using nfsd_lookup??
		 * Different "."/".." handling?  Something else?
		 * At least, add a comment here to explain....
		 */
		err = nfsd_cross_mnt(cd->rd_rqstp, &dentry, &exp);
		if (err) {
			nfserr = nfserrno(err);
			goto out_put;
		}
		nfserr = check_nfsd_access(exp, cd->rd_rqstp);
		if (nfserr)
			goto out_put;

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

static __be32 *
nfsd4_encode_rdattr_error(__be32 *p, int buflen, __be32 nfserr)
{
	__be32 *attrlenp;

	if (buflen < 6)
		return NULL;
	*p++ = htonl(2);
	*p++ = htonl(FATTR4_WORD0_RDATTR_ERROR); /* bmval0 */
	*p++ = htonl(0);			 /* bmval1 */

	attrlenp = p++;
	*p++ = nfserr;       /* no htonl */
	*attrlenp = htonl((char *)p - (char *)attrlenp - 4);
	return p;
}

static int
nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
		    loff_t offset, u64 ino, unsigned int d_type)
{
	struct readdir_cd *ccd = ccdv;
	struct nfsd4_readdir *cd = container_of(ccd, struct nfsd4_readdir, common);
	int buflen;
	__be32 *p = cd->buffer;
	__be32 *cookiep;
	__be32 nfserr = nfserr_toosmall;

	/* In nfsv4, "." and ".." never make it onto the wire.. */
	if (name && isdotent(name, namlen)) {
		cd->common.err = nfs_ok;
		return 0;
	}

	if (cd->offset)
		xdr_encode_hyper(cd->offset, (u64) offset);

	buflen = cd->buflen - 4 - XDR_QUADLEN(namlen);
	if (buflen < 0)
		goto fail;

	*p++ = xdr_one;                             /* mark entry present */
	cookiep = p;
	p = xdr_encode_hyper(p, NFS_OFFSET_MAX);    /* offset of next entry */
	p = xdr_encode_array(p, name, namlen);      /* name length & name */

	nfserr = nfsd4_encode_dirent_fattr(cd, name, namlen, p, &buflen);
	switch (nfserr) {
	case nfs_ok:
		p += buflen;
		break;
	case nfserr_resource:
		nfserr = nfserr_toosmall;
		goto fail;
	case nfserr_noent:
		goto skip_entry;
	default:
		/*
		 * If the client requested the RDATTR_ERROR attribute,
		 * we stuff the error code into this attribute
		 * and continue.  If this attribute was not requested,
		 * then in accordance with the spec, we fail the
		 * entire READDIR operation(!)
		 */
		if (!(cd->rd_bmval[0] & FATTR4_WORD0_RDATTR_ERROR))
			goto fail;
		p = nfsd4_encode_rdattr_error(p, buflen, nfserr);
		if (p == NULL) {
			nfserr = nfserr_toosmall;
			goto fail;
		}
	}
	cd->buflen -= (p - cd->buffer);
	cd->buffer = p;
	cd->offset = cookiep;
skip_entry:
	cd->common.err = nfs_ok;
	return 0;
fail:
	cd->common.err = nfserr;
	return -EINVAL;
}

static void
nfsd4_encode_stateid(struct nfsd4_compoundres *resp, stateid_t *sid)
{
	__be32 *p;

	RESERVE_SPACE(sizeof(stateid_t));
	WRITE32(sid->si_generation);
	WRITEMEM(&sid->si_opaque, sizeof(stateid_opaque_t));
	ADJUST_ARGS();
}

static __be32
nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
{
	__be32 *p;

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

static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
{
	__be32 *p;

	if (!nfserr) {
		RESERVE_SPACE(NFS4_MAX_SESSIONID_LEN + 8);
		WRITEMEM(bcts->sessionid.data, NFS4_MAX_SESSIONID_LEN);
		WRITE32(bcts->dir);
		/* XXX: ? */
		WRITE32(0);
		ADJUST_ARGS();
	}
	return nfserr;
}

static __be32
nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_close *close)
{
	ENCODE_SEQID_OP_HEAD;

	if (!nfserr)
		nfsd4_encode_stateid(resp, &close->cl_stateid);

	ENCODE_SEQID_OP_TAIL(close->cl_stateowner);
	return nfserr;
}


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

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

static __be32
nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_create *create)
{
	__be32 *p;

	if (!nfserr) {
		RESERVE_SPACE(32);
		write_cinfo(&p, &create->cr_cinfo);
		WRITE32(2);
		WRITE32(create->cr_bmval[0]);
		WRITE32(create->cr_bmval[1]);
		ADJUST_ARGS();
	}
	return nfserr;
}

static __be32
nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_getattr *getattr)
{
	struct svc_fh *fhp = getattr->ga_fhp;
	int buflen;

	if (nfserr)
		return nfserr;

	buflen = resp->end - resp->p - (COMPOUND_ERR_SLACK_SPACE >> 2);
	nfserr = nfsd4_encode_fattr(fhp, fhp->fh_export, fhp->fh_dentry,
				    resp->p, &buflen, getattr->ga_bmval,
				    resp->rqstp, 0);
	if (!nfserr)
		resp->p += buflen;
	return nfserr;
}

static __be32
nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr, struct svc_fh **fhpp)
{
	struct svc_fh *fhp = *fhpp;
	unsigned int len;
	__be32 *p;

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

/*
* Including all fields other than the name, a LOCK4denied structure requires
*   8(clientid) + 4(namelen) + 8(offset) + 8(length) + 4(type) = 32 bytes.
*/
static void
nfsd4_encode_lock_denied(struct nfsd4_compoundres *resp, struct nfsd4_lock_denied *ld)
{
	__be32 *p;

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

static __be32
nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lock *lock)
{
	ENCODE_SEQID_OP_HEAD;

	if (!nfserr)
		nfsd4_encode_stateid(resp, &lock->lk_resp_stateid);
	else if (nfserr == nfserr_denied)
		nfsd4_encode_lock_denied(resp, &lock->lk_denied);

	ENCODE_SEQID_OP_TAIL(lock->lk_replay_owner);
	return nfserr;
}

static __be32
nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lockt *lockt)
{
	if (nfserr == nfserr_denied)
		nfsd4_encode_lock_denied(resp, &lockt->lt_denied);
	return nfserr;
}

static __be32
nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_locku *locku)
{
	ENCODE_SEQID_OP_HEAD;

	if (!nfserr)
		nfsd4_encode_stateid(resp, &locku->lu_stateid);

	ENCODE_SEQID_OP_TAIL(locku->lu_stateowner);
	return nfserr;
}


static __be32
nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_link *link)
{
	__be32 *p;

	if (!nfserr) {
		RESERVE_SPACE(20);
		write_cinfo(&p, &link->li_cinfo);
		ADJUST_ARGS();
	}
	return nfserr;
}


static __be32
nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open *open)
{
	__be32 *p;
	ENCODE_SEQID_OP_HEAD;

	if (nfserr)
		goto out;

	nfsd4_encode_stateid(resp, &open->op_stateid);
	RESERVE_SPACE(40);
	write_cinfo(&p, &open->op_cinfo);
	WRITE32(open->op_rflags);
	WRITE32(2);
	WRITE32(open->op_bmval[0]);
	WRITE32(open->op_bmval[1]);
	WRITE32(open->op_delegate_type);
	ADJUST_ARGS();

	switch (open->op_delegate_type) {
	case NFS4_OPEN_DELEGATE_NONE:
		break;
	case NFS4_OPEN_DELEGATE_READ:
		nfsd4_encode_stateid(resp, &open->op_delegate_stateid);
		RESERVE_SPACE(20);
		WRITE32(open->op_recall);

		/*
		 * TODO: ACE's in delegations
		 */
		WRITE32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
		WRITE32(0);
		WRITE32(0);
		WRITE32(0);   /* XXX: is NULL principal ok? */
		ADJUST_ARGS();
		break;
	case NFS4_OPEN_DELEGATE_WRITE:
		nfsd4_encode_stateid(resp, &open->op_delegate_stateid);
		RESERVE_SPACE(32);
		WRITE32(0);

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

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

static __be32
nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_confirm *oc)
{
	ENCODE_SEQID_OP_HEAD;

	if (!nfserr)
		nfsd4_encode_stateid(resp, &oc->oc_resp_stateid);

	ENCODE_SEQID_OP_TAIL(oc->oc_stateowner);
	return nfserr;
}

static __be32
nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_downgrade *od)
{
	ENCODE_SEQID_OP_HEAD;

	if (!nfserr)
		nfsd4_encode_stateid(resp, &od->od_stateid);

	ENCODE_SEQID_OP_TAIL(od->od_stateowner);
	return nfserr;
}

static __be32
nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
		  struct nfsd4_read *read)
{
	u32 eof;
	int v, pn;
	unsigned long maxcount; 
	long len;
	__be32 *p;

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

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

	maxcount = svc_max_payload(resp->rqstp);
	if (maxcount > read->rd_length)
		maxcount = read->rd_length;

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

	nfserr = nfsd_read_file(read->rd_rqstp, read->rd_fhp, read->rd_filp,
			read->rd_offset, resp->rqstp->rq_vec, read->rd_vlen,
			&maxcount);

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

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

	/* Use rest of head for padding and remaining ops: */
	resp->xbuf->tail[0].iov_base = p;
	resp->xbuf->tail[0].iov_len = 0;
	if (maxcount&3) {
		RESERVE_SPACE(4);
		WRITE32(0);
		resp->xbuf->tail[0].iov_base += maxcount&3;
		resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
		ADJUST_ARGS();
	}
	return 0;
}

static __be32
nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readlink *readlink)
{
	int maxcount;
	char *page;
	__be32 *p;

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

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

	maxcount = PAGE_SIZE;
	RESERVE_SPACE(4);

	/*
	 * XXX: By default, the ->readlink() VFS op will truncate symlinks
	 * if they would overflow the buffer.  Is this kosher in NFSv4?  If
	 * not, one easy fix is: if ->readlink() precisely fills the buffer,
	 * assume that truncation occurred, and return NFS4ERR_RESOURCE.
	 */
	nfserr = nfsd_readlink(readlink->rl_rqstp, readlink->rl_fhp, page, &maxcount);
	if (nfserr == nfserr_isdir)
		return nfserr_inval;
	if (nfserr)
		return nfserr;

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

	/* Use rest of head for padding and remaining ops: */
	resp->xbuf->tail[0].iov_base = p;
	resp->xbuf->tail[0].iov_len = 0;
	if (maxcount&3) {
		RESERVE_SPACE(4);
		WRITE32(0);
		resp->xbuf->tail[0].iov_base += maxcount&3;
		resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
		ADJUST_ARGS();
	}
	return 0;
}

static __be32
nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readdir *readdir)
{
	int maxcount;
	loff_t offset;
	__be32 *page, *savep, *tailbase;
	__be32 *p;

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

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

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

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

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

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

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

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

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

	/* Use rest of head for padding and remaining ops: */
	resp->xbuf->tail[0].iov_base = tailbase;
	resp->xbuf->tail[0].iov_len = 0;
	resp->p = resp->xbuf->tail[0].iov_base;
	resp->end = resp->p + (PAGE_SIZE - resp->xbuf->head[0].iov_len)/4;

	return 0;
err_no_verf:
	p = savep;
	ADJUST_ARGS();
	return nfserr;
}

static __be32
nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_remove *remove)
{
	__be32 *p;

	if (!nfserr) {
		RESERVE_SPACE(20);
		write_cinfo(&p, &remove->rm_cinfo);
		ADJUST_ARGS();
	}
	return nfserr;
}

static __be32
nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_rename *rename)
{
	__be32 *p;

	if (!nfserr) {
		RESERVE_SPACE(40);
		write_cinfo(&p, &rename->rn_sinfo);
		write_cinfo(&p, &rename->rn_tinfo);
		ADJUST_ARGS();
	}
	return nfserr;
}

static __be32
nfsd4_do_encode_secinfo(struct nfsd4_compoundres *resp,
			 __be32 nfserr,struct svc_export *exp)
{
	int i = 0;
	u32 nflavs;
	struct exp_flavor_info *flavs;
	struct exp_flavor_info def_flavs[2];
	__be32 *p;

	if (nfserr)
		goto out;
	if (exp->ex_nflavors) {
		flavs = exp->ex_flavors;
		nflavs = exp->ex_nflavors;
	} else { /* Handling of some defaults in absence of real secinfo: */
		flavs = def_flavs;
		if (exp->ex_client->flavour->flavour == RPC_AUTH_UNIX) {
			nflavs = 2;
			flavs[0].pseudoflavor = RPC_AUTH_UNIX;
			flavs[1].pseudoflavor = RPC_AUTH_NULL;
		} else if (exp->ex_client->flavour->flavour == RPC_AUTH_GSS) {
			nflavs = 1;
			flavs[0].pseudoflavor
					= svcauth_gss_flavor(exp->ex_client);
		} else {
			nflavs = 1;
			flavs[0].pseudoflavor
					= exp->ex_client->flavour->flavour;
		}
	}

	RESERVE_SPACE(4);
	WRITE32(nflavs);
	ADJUST_ARGS();
	for (i = 0; i < nflavs; i++) {
		u32 flav = flavs[i].pseudoflavor;
		struct gss_api_mech *gm = gss_mech_get_by_pseudoflavor(flav);

		if (gm) {
			RESERVE_SPACE(4);
			WRITE32(RPC_AUTH_GSS);
			ADJUST_ARGS();
			RESERVE_SPACE(4 + gm->gm_oid.len);
			WRITE32(gm->gm_oid.len);
			WRITEMEM(gm->gm_oid.data, gm->gm_oid.len);
			ADJUST_ARGS();
			RESERVE_SPACE(4);
			WRITE32(0); /* qop */
			ADJUST_ARGS();
			RESERVE_SPACE(4);
			WRITE32(gss_pseudoflavor_to_service(gm, flav));
			ADJUST_ARGS();
			gss_mech_put(gm);
		} else {
			RESERVE_SPACE(4);
			WRITE32(flav);
			ADJUST_ARGS();
		}
	}
out:
	if (exp)
		exp_put(exp);
	return nfserr;
}

static __be32
nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
		     struct nfsd4_secinfo *secinfo)
{
	return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->si_exp);
}

static __be32
nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
		     struct nfsd4_secinfo_no_name *secinfo)
{
	return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->sin_exp);
}

/*
 * The SETATTR encode routine is special -- it always encodes a bitmap,
 * regardless of the error status.
 */
static __be32
nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setattr *setattr)
{
	__be32 *p;

	RESERVE_SPACE(12);
	if (nfserr) {
		WRITE32(2);
		WRITE32(0);
		WRITE32(0);
	}
	else {
		WRITE32(2);
		WRITE32(setattr->sa_bmval[0]);
		WRITE32(setattr->sa_bmval[1]);
	}
	ADJUST_ARGS();
	return nfserr;
}

static __be32
nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
{
	__be32 *p;

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

static __be32
nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_write *write)
{
	__be32 *p;

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

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

	if (nfserr)
		return nfserr;

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

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

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

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

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

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

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

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

	if (nfserr)
		return nfserr;

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

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

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

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

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

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

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

	if (nfserr)
		return nfserr;

	RESERVE_SPACE(NFS4_MAX_SESSIONID_LEN + 20);
	WRITEMEM(seq->sessionid.data, NFS4_MAX_SESSIONID_LEN);
	WRITE32(seq->seqid);
	WRITE32(seq->slotid);
	WRITE32(seq->maxslots);
	/* For now: target_maxslots = maxslots */
	WRITE32(seq->maxslots);
	WRITE32(seq->status_flags);

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

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

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

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

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

/*
 * Calculate the total amount of memory that the compound response has taken
 * after encoding the current operation.
 *
 * pad: add on 8 bytes for the next operation's op_code and status so that
 * there is room to cache a failure on the next operation.
 *
 * Compare this length to the session se_fmaxresp_cached.
 *
 * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so
 * will be at least a page and will therefore hold the xdr_buf head.
 */
static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)
{
	int status = 0;
	struct xdr_buf *xb = &resp->rqstp->rq_res;
	struct nfsd4_compoundargs *args = resp->rqstp->rq_argp;
	struct nfsd4_session *session = NULL;
	struct nfsd4_slot *slot = resp->cstate.slot;
	u32 length, tlen = 0, pad = 8;

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

	session = resp->cstate.session;
	if (session == NULL || slot->sl_cachethis == 0)
		return status;

	if (resp->opcnt >= args->opcnt)
		pad = 0; /* this is the last operation */

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

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

	if (length <= session->se_fchannel.maxresp_cached)
		return status;
	else
		return nfserr_rep_too_big_to_cache;
}

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

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

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

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

	BUG_ON(!rp);

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

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

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

void nfsd4_release_compoundargs(struct nfsd4_compoundargs *args)
{
	if (args->ops != args->iops) {
		kfree(args->ops);
		args->ops = args->iops;
	}
	kfree(args->tmpp);
	args->tmpp = NULL;
	while (args->to_free) {
		struct tmpbuf *tb = args->to_free;
		args->to_free = tb->next;
		tb->release(tb->buf);
		kfree(tb);
	}
}

int
nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compoundargs *args)
{
	__be32 status;

	args->p = p;
	args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len;
	args->pagelist = rqstp->rq_arg.pages;
	args->pagelen = rqstp->rq_arg.page_len;
	args->tmpp = NULL;
	args->to_free = NULL;
	args->ops = args->iops;
	args->rqstp = rqstp;

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

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

	if (rqstp->rq_res.page_len) 
		iov = &rqstp->rq_res.tail[0];
	else
		iov = &rqstp->rq_res.head[0];
	iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
	BUG_ON(iov->iov_len > PAGE_SIZE);
	if (nfsd4_has_session(cs)) {
		if (cs->status != nfserr_replay_cache) {
			nfsd4_store_cache_entry(resp);
			dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
			cs->slot->sl_inuse = false;
		}
		/* Renew the clientid on success and on replay */
		release_session_client(cs->session);
		nfsd4_put_session(cs->session);
	}
	return 1;
}

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