fs/nfsd/nfs4xdr.c - linux - Git at Google

 /*
  *  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.
  */

 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/namei.h>
 #include <linux/statfs.h>
 #include <linux/utsname.h>
 #include <linux/pagemap.h>
 #include <linux/sunrpc/svcauth_gss.h>
 #include <linux/sunrpc/addr.h>
 #include <linux/xattr.h>
 #include <uapi/linux/xattr.h>

 #include "idmap.h"
 #include "acl.h"
 #include "xdr4.h"
 #include "vfs.h"
 #include "state.h"
 #include "cache.h"
 #include "netns.h"
 #include "pnfs.h"
 #include "filecache.h"

 #include "trace.h"

 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 #include <linux/security.h>
 #endif


 #define NFSDDBG_FACILITY		NFSDDBG_XDR

 const u32 nfsd_suppattrs[3][3] = {
 	{NFSD4_SUPPORTED_ATTRS_WORD0,
 	 NFSD4_SUPPORTED_ATTRS_WORD1,
 	 NFSD4_SUPPORTED_ATTRS_WORD2},

 	{NFSD4_1_SUPPORTED_ATTRS_WORD0,
 	 NFSD4_1_SUPPORTED_ATTRS_WORD1,
 	 NFSD4_1_SUPPORTED_ATTRS_WORD2},

 	{NFSD4_1_SUPPORTED_ATTRS_WORD0,
 	 NFSD4_1_SUPPORTED_ATTRS_WORD1,
 	 NFSD4_2_SUPPORTED_ATTRS_WORD2},
 };

 /*
  * 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)
 {
 	int i;

 	if (len == 0)
 		return nfserr_inval;
 	if (len > NFS4_MAXNAMLEN)
 		return nfserr_nametoolong;
 	if (isdotent(str, len))
 		return nfserr_badname;
 	for (i = 0; i < len; i++)
 		if (str[i] == '/')
 			return nfserr_badname;
 	return 0;
 }

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

 /**
  * svcxdr_tmpalloc - allocate memory to be freed after compound processing
  * @argp: NFSv4 compound argument structure
  * @len: length of buffer to allocate
  *
  * Allocates a buffer of size @len to be freed when processing the compound
  * operation described in @argp finishes.
  */
 static void *
 svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, u32 len)
 {
 	struct svcxdr_tmpbuf *tb;

 	tb = kmalloc(sizeof(*tb) + len, GFP_KERNEL);
 	if (!tb)
 		return NULL;
 	tb->next = argp->to_free;
 	argp->to_free = tb;
 	return tb->buf;
 }

 /*
  * For xdr strings that need to be passed to other kernel api's
  * as null-terminated strings.
  *
  * Note null-terminating in place usually isn't safe since the
  * buffer might end on a page boundary.
  */
 static char *
 svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len)
 {
 	char *p = svcxdr_tmpalloc(argp, len + 1);

 	if (!p)
 		return NULL;
 	memcpy(p, buf, len);
 	p[len] = '\0';
 	return p;
 }

 static void *
 svcxdr_savemem(struct nfsd4_compoundargs *argp, __be32 *p, u32 len)
 {
 	__be32 *tmp;

 	/*
 	 * The location of the decoded data item is stable,
 	 * so @p is OK to use. This is the common case.
 	 */
 	if (p != argp->xdr->scratch.iov_base)
 		return p;

 	tmp = svcxdr_tmpalloc(argp, len);
 	if (!tmp)
 		return NULL;
 	memcpy(tmp, p, len);
 	return tmp;
 }

 /*
  * NFSv4 basic data type decoders
  */

 /*
  * This helper handles variable-length opaques which belong to protocol
  * elements that this implementation does not support.
  */
 static __be32
 nfsd4_decode_ignored_string(struct nfsd4_compoundargs *argp, u32 maxlen)
 {
 	u32 len;

 	if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
 		return nfserr_bad_xdr;
 	if (maxlen && len > maxlen)
 		return nfserr_bad_xdr;
 	if (!xdr_inline_decode(argp->xdr, len))
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_netobj *o)
 {
 	__be32 *p;
 	u32 len;

 	if (xdr_stream_decode_u32(argp->xdr, &len) < 0)
 		return nfserr_bad_xdr;
 	if (len == 0 || len > NFS4_OPAQUE_LIMIT)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, len);
 	if (!p)
 		return nfserr_bad_xdr;
 	o->data = svcxdr_savemem(argp, p, len);
 	if (!o->data)
 		return nfserr_jukebox;
 	o->len = len;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_component4(struct nfsd4_compoundargs *argp, char **namp, u32 *lenp)
 {
 	__be32 *p, status;

 	if (xdr_stream_decode_u32(argp->xdr, lenp) < 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, *lenp);
 	if (!p)
 		return nfserr_bad_xdr;
 	status = check_filename((char *)p, *lenp);
 	if (status)
 		return status;
 	*namp = svcxdr_savemem(argp, p, *lenp);
 	if (!*namp)
 		return nfserr_jukebox;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_nfstime4(struct nfsd4_compoundargs *argp, struct timespec64 *tv)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, XDR_UNIT * 3);
 	if (!p)
 		return nfserr_bad_xdr;
 	p = xdr_decode_hyper(p, &tv->tv_sec);
 	tv->tv_nsec = be32_to_cpup(p++);
 	if (tv->tv_nsec >= (u32)1000000000)
 		return nfserr_inval;
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_verifier4(struct nfsd4_compoundargs *argp, nfs4_verifier *verf)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, NFS4_VERIFIER_SIZE);
 	if (!p)
 		return nfserr_bad_xdr;
 	memcpy(verf->data, p, sizeof(verf->data));
 	return nfs_ok;
 }

 /**
  * nfsd4_decode_bitmap4 - Decode an NFSv4 bitmap4
  * @argp: NFSv4 compound argument structure
  * @bmval: pointer to an array of u32's to decode into
  * @bmlen: size of the @bmval array
  *
  * The server needs to return nfs_ok rather than nfserr_bad_xdr when
  * encountering bitmaps containing bits it does not recognize. This
  * includes bits in bitmap words past WORDn, where WORDn is the last
  * bitmap WORD the implementation currently supports. Thus we are
  * careful here to simply ignore bits in bitmap words that this
  * implementation has yet to support explicitly.
  *
  * Return values:
  *   %nfs_ok: @bmval populated successfully
  *   %nfserr_bad_xdr: the encoded bitmap was invalid
  */
 static __be32
 nfsd4_decode_bitmap4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen)
 {
 	u32 i, count;
 	__be32 *p;

 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;
 	/* request sanity */
 	if (count > 1000)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, count << 2);
 	if (!p)
 		return nfserr_bad_xdr;
 	for (i = 0; i < bmlen; i++)
 		bmval[i] = (i < count) ? be32_to_cpup(p++) : 0;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_nfsace4(struct nfsd4_compoundargs *argp, struct nfs4_ace *ace)
 {
 	__be32 *p, status;
 	u32 length;

 	if (xdr_stream_decode_u32(argp->xdr, &ace->type) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &ace->flag) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &ace->access_mask) < 0)
 		return nfserr_bad_xdr;

 	if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, length);
 	if (!p)
 		return nfserr_bad_xdr;
 	ace->whotype = nfs4_acl_get_whotype((char *)p, length);
 	if (ace->whotype != NFS4_ACL_WHO_NAMED)
 		status = nfs_ok;
 	else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
 		status = nfsd_map_name_to_gid(argp->rqstp,
 				(char *)p, length, &ace->who_gid);
 	else
 		status = nfsd_map_name_to_uid(argp->rqstp,
 				(char *)p, length, &ace->who_uid);

 	return status;
 }

 /* A counted array of nfsace4's */
 static noinline __be32
 nfsd4_decode_acl(struct nfsd4_compoundargs *argp, struct nfs4_acl **acl)
 {
 	struct nfs4_ace *ace;
 	__be32 status;
 	u32 count;

 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;

 	if (count > xdr_stream_remaining(argp->xdr) / 20)
 		/*
 		 * Even with 4-byte names there wouldn't be
 		 * space for that many aces; something fishy is
 		 * going on:
 		 */
 		return nfserr_fbig;

 	*acl = svcxdr_tmpalloc(argp, nfs4_acl_bytes(count));
 	if (*acl == NULL)
 		return nfserr_jukebox;

 	(*acl)->naces = count;
 	for (ace = (*acl)->aces; ace < (*acl)->aces + count; ace++) {
 		status = nfsd4_decode_nfsace4(argp, ace);
 		if (status)
 			return status;
 	}

 	return nfs_ok;
 }

 static noinline __be32
 nfsd4_decode_security_label(struct nfsd4_compoundargs *argp,
 			    struct xdr_netobj *label)
 {
 	u32 lfs, pi, length;
 	__be32 *p;

 	if (xdr_stream_decode_u32(argp->xdr, &lfs) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &pi) < 0)
 		return nfserr_bad_xdr;

 	if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
 		return nfserr_bad_xdr;
 	if (length > NFS4_MAXLABELLEN)
 		return nfserr_badlabel;
 	p = xdr_inline_decode(argp->xdr, length);
 	if (!p)
 		return nfserr_bad_xdr;
 	label->len = length;
 	label->data = svcxdr_dupstr(argp, p, length);
 	if (!label->data)
 		return nfserr_jukebox;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_fattr4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen,
 		    struct iattr *iattr, struct nfs4_acl **acl,
 		    struct xdr_netobj *label, int *umask)
 {
 	unsigned int starting_pos;
 	u32 attrlist4_count;
 	__be32 *p, status;

 	iattr->ia_valid = 0;
 	status = nfsd4_decode_bitmap4(argp, bmval, bmlen);
 	if (status)
 		return nfserr_bad_xdr;

 	if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
 	    || bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
 	    || bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2) {
 		if (nfsd_attrs_supported(argp->minorversion, bmval))
 			return nfserr_inval;
 		return nfserr_attrnotsupp;
 	}

 	if (xdr_stream_decode_u32(argp->xdr, &attrlist4_count) < 0)
 		return nfserr_bad_xdr;
 	starting_pos = xdr_stream_pos(argp->xdr);

 	if (bmval[0] & FATTR4_WORD0_SIZE) {
 		u64 size;

 		if (xdr_stream_decode_u64(argp->xdr, &size) < 0)
 			return nfserr_bad_xdr;
 		iattr->ia_size = size;
 		iattr->ia_valid |= ATTR_SIZE;
 	}
 	if (bmval[0] & FATTR4_WORD0_ACL) {
 		status = nfsd4_decode_acl(argp, acl);
 		if (status)
 			return status;
 	} else
 		*acl = NULL;
 	if (bmval[1] & FATTR4_WORD1_MODE) {
 		u32 mode;

 		if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
 			return nfserr_bad_xdr;
 		iattr->ia_mode = mode;
 		iattr->ia_mode &= (S_IFMT | S_IALLUGO);
 		iattr->ia_valid |= ATTR_MODE;
 	}
 	if (bmval[1] & FATTR4_WORD1_OWNER) {
 		u32 length;

 		if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
 			return nfserr_bad_xdr;
 		p = xdr_inline_decode(argp->xdr, length);
 		if (!p)
 			return nfserr_bad_xdr;
 		status = nfsd_map_name_to_uid(argp->rqstp, (char *)p, length,
 					      &iattr->ia_uid);
 		if (status)
 			return status;
 		iattr->ia_valid |= ATTR_UID;
 	}
 	if (bmval[1] & FATTR4_WORD1_OWNER_GROUP) {
 		u32 length;

 		if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
 			return nfserr_bad_xdr;
 		p = xdr_inline_decode(argp->xdr, length);
 		if (!p)
 			return nfserr_bad_xdr;
 		status = nfsd_map_name_to_gid(argp->rqstp, (char *)p, length,
 					      &iattr->ia_gid);
 		if (status)
 			return status;
 		iattr->ia_valid |= ATTR_GID;
 	}
 	if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
 		u32 set_it;

 		if (xdr_stream_decode_u32(argp->xdr, &set_it) < 0)
 			return nfserr_bad_xdr;
 		switch (set_it) {
 		case NFS4_SET_TO_CLIENT_TIME:
 			status = nfsd4_decode_nfstime4(argp, &iattr->ia_atime);
 			if (status)
 				return status;
 			iattr->ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
 			break;
 		case NFS4_SET_TO_SERVER_TIME:
 			iattr->ia_valid |= ATTR_ATIME;
 			break;
 		default:
 			return nfserr_bad_xdr;
 		}
 	}
 	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
 		u32 set_it;

 		if (xdr_stream_decode_u32(argp->xdr, &set_it) < 0)
 			return nfserr_bad_xdr;
 		switch (set_it) {
 		case NFS4_SET_TO_CLIENT_TIME:
 			status = nfsd4_decode_nfstime4(argp, &iattr->ia_mtime);
 			if (status)
 				return status;
 			iattr->ia_valid |= (ATTR_MTIME | ATTR_MTIME_SET);
 			break;
 		case NFS4_SET_TO_SERVER_TIME:
 			iattr->ia_valid |= ATTR_MTIME;
 			break;
 		default:
 			return nfserr_bad_xdr;
 		}
 	}
 	label->len = 0;
 	if (IS_ENABLED(CONFIG_NFSD_V4_SECURITY_LABEL) &&
 	    bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 		status = nfsd4_decode_security_label(argp, label);
 		if (status)
 			return status;
 	}
 	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 		u32 mode, mask;

 		if (!umask)
 			return nfserr_bad_xdr;
 		if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
 			return nfserr_bad_xdr;
 		iattr->ia_mode = mode & (S_IFMT | S_IALLUGO);
 		if (xdr_stream_decode_u32(argp->xdr, &mask) < 0)
 			return nfserr_bad_xdr;
 		*umask = mask & S_IRWXUGO;
 		iattr->ia_valid |= ATTR_MODE;
 	}

 	/* request sanity: did attrlist4 contain the expected number of words? */
 	if (attrlist4_count != xdr_stream_pos(argp->xdr) - starting_pos)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_stateid4(struct nfsd4_compoundargs *argp, stateid_t *sid)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, NFS4_STATEID_SIZE);
 	if (!p)
 		return nfserr_bad_xdr;
 	sid->si_generation = be32_to_cpup(p++);
 	memcpy(&sid->si_opaque, p, sizeof(sid->si_opaque));
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_clientid4(struct nfsd4_compoundargs *argp, clientid_t *clientid)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, sizeof(__be64));
 	if (!p)
 		return nfserr_bad_xdr;
 	memcpy(clientid, p, sizeof(*clientid));
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_state_owner4(struct nfsd4_compoundargs *argp,
 			  clientid_t *clientid, struct xdr_netobj *owner)
 {
 	__be32 status;

 	status = nfsd4_decode_clientid4(argp, clientid);
 	if (status)
 		return status;
 	return nfsd4_decode_opaque(argp, owner);
 }

 #ifdef CONFIG_NFSD_PNFS
 static __be32
 nfsd4_decode_deviceid4(struct nfsd4_compoundargs *argp,
 		       struct nfsd4_deviceid *devid)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, NFS4_DEVICEID4_SIZE);
 	if (!p)
 		return nfserr_bad_xdr;
 	memcpy(devid, p, sizeof(*devid));
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_layoutupdate4(struct nfsd4_compoundargs *argp,
 			   struct nfsd4_layoutcommit *lcp)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &lcp->lc_layout_type) < 0)
 		return nfserr_bad_xdr;
 	if (lcp->lc_layout_type < LAYOUT_NFSV4_1_FILES)
 		return nfserr_bad_xdr;
 	if (lcp->lc_layout_type >= LAYOUT_TYPE_MAX)
 		return nfserr_bad_xdr;

 	if (xdr_stream_decode_u32(argp->xdr, &lcp->lc_up_len) < 0)
 		return nfserr_bad_xdr;
 	if (lcp->lc_up_len > 0) {
 		lcp->lc_up_layout = xdr_inline_decode(argp->xdr, lcp->lc_up_len);
 		if (!lcp->lc_up_layout)
 			return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_layoutreturn4(struct nfsd4_compoundargs *argp,
 			   struct nfsd4_layoutreturn *lrp)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_return_type) < 0)
 		return nfserr_bad_xdr;
 	switch (lrp->lr_return_type) {
 	case RETURN_FILE:
 		if (xdr_stream_decode_u64(argp->xdr, &lrp->lr_seg.offset) < 0)
 			return nfserr_bad_xdr;
 		if (xdr_stream_decode_u64(argp->xdr, &lrp->lr_seg.length) < 0)
 			return nfserr_bad_xdr;
 		status = nfsd4_decode_stateid4(argp, &lrp->lr_sid);
 		if (status)
 			return status;
 		if (xdr_stream_decode_u32(argp->xdr, &lrp->lrf_body_len) < 0)
 			return nfserr_bad_xdr;
 		if (lrp->lrf_body_len > 0) {
 			lrp->lrf_body = xdr_inline_decode(argp->xdr, lrp->lrf_body_len);
 			if (!lrp->lrf_body)
 				return nfserr_bad_xdr;
 		}
 		break;
 	case RETURN_FSID:
 	case RETURN_ALL:
 		lrp->lr_seg.offset = 0;
 		lrp->lr_seg.length = NFS4_MAX_UINT64;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 #endif /* CONFIG_NFSD_PNFS */

 static __be32
 nfsd4_decode_sessionid4(struct nfsd4_compoundargs *argp,
 			struct nfs4_sessionid *sessionid)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, NFS4_MAX_SESSIONID_LEN);
 	if (!p)
 		return nfserr_bad_xdr;
 	memcpy(sessionid->data, p, sizeof(sessionid->data));
 	return nfs_ok;
 }

 /* Defined in Appendix A of RFC 5531 */
 static __be32
 nfsd4_decode_authsys_parms(struct nfsd4_compoundargs *argp,
 			   struct nfsd4_cb_sec *cbs)
 {
 	u32 stamp, gidcount, uid, gid;
 	__be32 *p, status;

 	if (xdr_stream_decode_u32(argp->xdr, &stamp) < 0)
 		return nfserr_bad_xdr;
 	/* machine name */
 	status = nfsd4_decode_ignored_string(argp, 255);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &uid) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &gid) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &gidcount) < 0)
 		return nfserr_bad_xdr;
 	if (gidcount > 16)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, gidcount << 2);
 	if (!p)
 		return nfserr_bad_xdr;
 	if (cbs->flavor == (u32)(-1)) {
 		struct user_namespace *userns = nfsd_user_namespace(argp->rqstp);

 		kuid_t kuid = make_kuid(userns, uid);
 		kgid_t kgid = make_kgid(userns, gid);
 		if (uid_valid(kuid) && gid_valid(kgid)) {
 			cbs->uid = kuid;
 			cbs->gid = kgid;
 			cbs->flavor = RPC_AUTH_UNIX;
 		} else {
 			dprintk("RPC_AUTH_UNIX with invalid uid or gid, ignoring!\n");
 		}
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_gss_cb_handles4(struct nfsd4_compoundargs *argp,
 			     struct nfsd4_cb_sec *cbs)
 {
 	__be32 status;
 	u32 service;

 	dprintk("RPC_AUTH_GSS callback secflavor not supported!\n");

 	if (xdr_stream_decode_u32(argp->xdr, &service) < 0)
 		return nfserr_bad_xdr;
 	if (service < RPC_GSS_SVC_NONE || service > RPC_GSS_SVC_PRIVACY)
 		return nfserr_bad_xdr;
 	/* gcbp_handle_from_server */
 	status = nfsd4_decode_ignored_string(argp, 0);
 	if (status)
 		return status;
 	/* gcbp_handle_from_client */
 	status = nfsd4_decode_ignored_string(argp, 0);
 	if (status)
 		return status;

 	return nfs_ok;
 }

 /* a counted array of callback_sec_parms4 items */
 static __be32
 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_cb_sec *cbs)
 {
 	u32 i, secflavor, nr_secflavs;
 	__be32 status;

 	/* callback_sec_params4 */
 	if (xdr_stream_decode_u32(argp->xdr, &nr_secflavs) < 0)
 		return nfserr_bad_xdr;
 	if (nr_secflavs)
 		cbs->flavor = (u32)(-1);
 	else
 		/* Is this legal? Be generous, take it to mean AUTH_NONE: */
 		cbs->flavor = 0;

 	for (i = 0; i < nr_secflavs; ++i) {
 		if (xdr_stream_decode_u32(argp->xdr, &secflavor) < 0)
 			return nfserr_bad_xdr;
 		switch (secflavor) {
 		case RPC_AUTH_NULL:
 			/* void */
 			if (cbs->flavor == (u32)(-1))
 				cbs->flavor = RPC_AUTH_NULL;
 			break;
 		case RPC_AUTH_UNIX:
 			status = nfsd4_decode_authsys_parms(argp, cbs);
 			if (status)
 				return status;
 			break;
 		case RPC_AUTH_GSS:
 			status = nfsd4_decode_gss_cb_handles4(argp, cbs);
 			if (status)
 				return status;
 			break;
 		default:
 			return nfserr_inval;
 		}
 	}

 	return nfs_ok;
 }


 /*
  * NFSv4 operation argument decoders
  */

 static __be32
 nfsd4_decode_access(struct nfsd4_compoundargs *argp,
 		    struct nfsd4_access *access)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &access->ac_req_access) < 0)
 		return nfserr_bad_xdr;
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_close(struct nfsd4_compoundargs *argp, struct nfsd4_close *close)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &close->cl_seqid) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_stateid4(argp, &close->cl_stateid);
 }


 static __be32
 nfsd4_decode_commit(struct nfsd4_compoundargs *argp, struct nfsd4_commit *commit)
 {
 	if (xdr_stream_decode_u64(argp->xdr, &commit->co_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &commit->co_count) < 0)
 		return nfserr_bad_xdr;
 	return nfs_ok;
 }

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

 	if (xdr_stream_decode_u32(argp->xdr, &create->cr_type) < 0)
 		return nfserr_bad_xdr;
 	switch (create->cr_type) {
 	case NF4LNK:
 		if (xdr_stream_decode_u32(argp->xdr, &create->cr_datalen) < 0)
 			return nfserr_bad_xdr;
 		p = xdr_inline_decode(argp->xdr, create->cr_datalen);
 		if (!p)
 			return nfserr_bad_xdr;
 		create->cr_data = svcxdr_dupstr(argp, p, create->cr_datalen);
 		if (!create->cr_data)
 			return nfserr_jukebox;
 		break;
 	case NF4BLK:
 	case NF4CHR:
 		if (xdr_stream_decode_u32(argp->xdr, &create->cr_specdata1) < 0)
 			return nfserr_bad_xdr;
 		if (xdr_stream_decode_u32(argp->xdr, &create->cr_specdata2) < 0)
 			return nfserr_bad_xdr;
 		break;
 	case NF4SOCK:
 	case NF4FIFO:
 	case NF4DIR:
 	default:
 		break;
 	}
 	status = nfsd4_decode_component4(argp, &create->cr_name,
 					 &create->cr_namelen);
 	if (status)
 		return status;
 	status = nfsd4_decode_fattr4(argp, create->cr_bmval,
 				    ARRAY_SIZE(create->cr_bmval),
 				    &create->cr_iattr, &create->cr_acl,
 				    &create->cr_label, &create->cr_umask);
 	if (status)
 		return status;

 	return nfs_ok;
 }

 static inline __be32
 nfsd4_decode_delegreturn(struct nfsd4_compoundargs *argp, struct nfsd4_delegreturn *dr)
 {
 	return nfsd4_decode_stateid4(argp, &dr->dr_stateid);
 }

 static inline __be32
 nfsd4_decode_getattr(struct nfsd4_compoundargs *argp, struct nfsd4_getattr *getattr)
 {
 	return nfsd4_decode_bitmap4(argp, getattr->ga_bmval,
 				    ARRAY_SIZE(getattr->ga_bmval));
 }

 static __be32
 nfsd4_decode_link(struct nfsd4_compoundargs *argp, struct nfsd4_link *link)
 {
 	return nfsd4_decode_component4(argp, &link->li_name, &link->li_namelen);
 }

 static __be32
 nfsd4_decode_open_to_lock_owner4(struct nfsd4_compoundargs *argp,
 				 struct nfsd4_lock *lock)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &lock->lk_new_open_seqid) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_stateid4(argp, &lock->lk_new_open_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &lock->lk_new_lock_seqid) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_state_owner4(argp, &lock->lk_new_clientid,
 					 &lock->lk_new_owner);
 }

 static __be32
 nfsd4_decode_exist_lock_owner4(struct nfsd4_compoundargs *argp,
 			       struct nfsd4_lock *lock)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &lock->lk_old_lock_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &lock->lk_old_lock_seqid) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_locker4(struct nfsd4_compoundargs *argp, struct nfsd4_lock *lock)
 {
 	if (xdr_stream_decode_bool(argp->xdr, &lock->lk_is_new) < 0)
 		return nfserr_bad_xdr;
 	if (lock->lk_is_new)
 		return nfsd4_decode_open_to_lock_owner4(argp, lock);
 	return nfsd4_decode_exist_lock_owner4(argp, lock);
 }

 static __be32
 nfsd4_decode_lock(struct nfsd4_compoundargs *argp, struct nfsd4_lock *lock)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &lock->lk_type) < 0)
 		return nfserr_bad_xdr;
 	if ((lock->lk_type < NFS4_READ_LT) || (lock->lk_type > NFS4_WRITEW_LT))
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_bool(argp->xdr, &lock->lk_reclaim) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lock->lk_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lock->lk_length) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_locker4(argp, lock);
 }

 static __be32
 nfsd4_decode_lockt(struct nfsd4_compoundargs *argp, struct nfsd4_lockt *lockt)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &lockt->lt_type) < 0)
 		return nfserr_bad_xdr;
 	if ((lockt->lt_type < NFS4_READ_LT) || (lockt->lt_type > NFS4_WRITEW_LT))
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lockt->lt_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lockt->lt_length) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_state_owner4(argp, &lockt->lt_clientid,
 					 &lockt->lt_owner);
 }

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

 	if (xdr_stream_decode_u32(argp->xdr, &locku->lu_type) < 0)
 		return nfserr_bad_xdr;
 	if ((locku->lu_type < NFS4_READ_LT) || (locku->lu_type > NFS4_WRITEW_LT))
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &locku->lu_seqid) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_stateid4(argp, &locku->lu_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &locku->lu_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &locku->lu_length) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_lookup(struct nfsd4_compoundargs *argp, struct nfsd4_lookup *lookup)
 {
 	return nfsd4_decode_component4(argp, &lookup->lo_name, &lookup->lo_len);
 }

 static __be32
 nfsd4_decode_createhow4(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &open->op_createmode) < 0)
 		return nfserr_bad_xdr;
 	switch (open->op_createmode) {
 	case NFS4_CREATE_UNCHECKED:
 	case NFS4_CREATE_GUARDED:
 		status = nfsd4_decode_fattr4(argp, open->op_bmval,
 					     ARRAY_SIZE(open->op_bmval),
 					     &open->op_iattr, &open->op_acl,
 					     &open->op_label, &open->op_umask);
 		if (status)
 			return status;
 		break;
 	case NFS4_CREATE_EXCLUSIVE:
 		status = nfsd4_decode_verifier4(argp, &open->op_verf);
 		if (status)
 			return status;
 		break;
 	case NFS4_CREATE_EXCLUSIVE4_1:
 		if (argp->minorversion < 1)
 			return nfserr_bad_xdr;
 		status = nfsd4_decode_verifier4(argp, &open->op_verf);
 		if (status)
 			return status;
 		status = nfsd4_decode_fattr4(argp, open->op_bmval,
 					     ARRAY_SIZE(open->op_bmval),
 					     &open->op_iattr, &open->op_acl,
 					     &open->op_label, &open->op_umask);
 		if (status)
 			return status;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_openflag4(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &open->op_create) < 0)
 		return nfserr_bad_xdr;
 	switch (open->op_create) {
 	case NFS4_OPEN_NOCREATE:
 		break;
 	case NFS4_OPEN_CREATE:
 		status = nfsd4_decode_createhow4(argp, open);
 		if (status)
 			return status;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32 nfsd4_decode_share_access(struct nfsd4_compoundargs *argp, u32 *share_access, u32 *deleg_want, u32 *deleg_when)
 {
 	u32 w;

 	if (xdr_stream_decode_u32(argp->xdr, &w) < 0)
 		return nfserr_bad_xdr;
 	*share_access = w & NFS4_SHARE_ACCESS_MASK;
 	*deleg_want = w & NFS4_SHARE_WANT_MASK;
 	if (deleg_when)
 		*deleg_when = w & NFS4_SHARE_WHEN_MASK;

 	switch (w & NFS4_SHARE_ACCESS_MASK) {
 	case NFS4_SHARE_ACCESS_READ:
 	case NFS4_SHARE_ACCESS_WRITE:
 	case NFS4_SHARE_ACCESS_BOTH:
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}
 	w &= ~NFS4_SHARE_ACCESS_MASK;
 	if (!w)
 		return nfs_ok;
 	if (!argp->minorversion)
 		return nfserr_bad_xdr;
 	switch (w & NFS4_SHARE_WANT_MASK) {
 	case NFS4_SHARE_WANT_NO_PREFERENCE:
 	case NFS4_SHARE_WANT_READ_DELEG:
 	case NFS4_SHARE_WANT_WRITE_DELEG:
 	case NFS4_SHARE_WANT_ANY_DELEG:
 	case NFS4_SHARE_WANT_NO_DELEG:
 	case NFS4_SHARE_WANT_CANCEL:
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}
 	w &= ~NFS4_SHARE_WANT_MASK;
 	if (!w)
 		return nfs_ok;

 	if (!deleg_when)	/* open_downgrade */
 		return nfserr_inval;
 	switch (w) {
 	case NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL:
 	case NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED:
 	case (NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL |
 	      NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED):
 		return nfs_ok;
 	}
 	return nfserr_bad_xdr;
 }

 static __be32 nfsd4_decode_share_deny(struct nfsd4_compoundargs *argp, u32 *x)
 {
 	if (xdr_stream_decode_u32(argp->xdr, x) < 0)
 		return nfserr_bad_xdr;
 	/* Note: unlike access bits, deny bits may be zero. */
 	if (*x & ~NFS4_SHARE_DENY_BOTH)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_open_claim4(struct nfsd4_compoundargs *argp,
 			 struct nfsd4_open *open)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &open->op_claim_type) < 0)
 		return nfserr_bad_xdr;
 	switch (open->op_claim_type) {
 	case NFS4_OPEN_CLAIM_NULL:
 	case NFS4_OPEN_CLAIM_DELEGATE_PREV:
 		status = nfsd4_decode_component4(argp, &open->op_fname,
 						 &open->op_fnamelen);
 		if (status)
 			return status;
 		break;
 	case NFS4_OPEN_CLAIM_PREVIOUS:
 		if (xdr_stream_decode_u32(argp->xdr, &open->op_delegate_type) < 0)
 			return nfserr_bad_xdr;
 		break;
 	case NFS4_OPEN_CLAIM_DELEGATE_CUR:
 		status = nfsd4_decode_stateid4(argp, &open->op_delegate_stateid);
 		if (status)
 			return status;
 		status = nfsd4_decode_component4(argp, &open->op_fname,
 						 &open->op_fnamelen);
 		if (status)
 			return status;
 		break;
 	case NFS4_OPEN_CLAIM_FH:
 	case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
 		if (argp->minorversion < 1)
 			return nfserr_bad_xdr;
 		/* void */
 		break;
 	case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
 		if (argp->minorversion < 1)
 			return nfserr_bad_xdr;
 		status = nfsd4_decode_stateid4(argp, &open->op_delegate_stateid);
 		if (status)
 			return status;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 {
 	__be32 status;
 	u32 dummy;

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

 	open->op_xdr_error = 0;
 	if (xdr_stream_decode_u32(argp->xdr, &open->op_seqid) < 0)
 		return nfserr_bad_xdr;
 	/* deleg_want is ignored */
 	status = nfsd4_decode_share_access(argp, &open->op_share_access,
 					   &open->op_deleg_want, &dummy);
 	if (status)
 		return status;
 	status = nfsd4_decode_share_deny(argp, &open->op_share_deny);
 	if (status)
 		return status;
 	status = nfsd4_decode_state_owner4(argp, &open->op_clientid,
 					   &open->op_owner);
 	if (status)
 		return status;
 	status = nfsd4_decode_openflag4(argp, open);
 	if (status)
 		return status;
 	return nfsd4_decode_open_claim4(argp, open);
 }

 static __be32
 nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_open_confirm *open_conf)
 {
 	__be32 status;

 	if (argp->minorversion >= 1)
 		return nfserr_notsupp;

 	status = nfsd4_decode_stateid4(argp, &open_conf->oc_req_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &open_conf->oc_seqid) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &open_down->od_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &open_down->od_seqid) < 0)
 		return nfserr_bad_xdr;
 	/* deleg_want is ignored */
 	status = nfsd4_decode_share_access(argp, &open_down->od_share_access,
 					   &open_down->od_deleg_want, NULL);
 	if (status)
 		return status;
 	return nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
 }

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

 	if (xdr_stream_decode_u32(argp->xdr, &putfh->pf_fhlen) < 0)
 		return nfserr_bad_xdr;
 	if (putfh->pf_fhlen > NFS4_FHSIZE)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, putfh->pf_fhlen);
 	if (!p)
 		return nfserr_bad_xdr;
 	putfh->pf_fhval = svcxdr_savemem(argp, p, putfh->pf_fhlen);
 	if (!putfh->pf_fhval)
 		return nfserr_jukebox;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_putpubfh(struct nfsd4_compoundargs *argp, void *p)
 {
 	if (argp->minorversion == 0)
 		return nfs_ok;
 	return nfserr_notsupp;
 }

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

 	status = nfsd4_decode_stateid4(argp, &read->rd_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &read->rd_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &read->rd_length) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

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

 	if (xdr_stream_decode_u64(argp->xdr, &readdir->rd_cookie) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_verifier4(argp, &readdir->rd_verf);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &readdir->rd_dircount) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &readdir->rd_maxcount) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_uint32_array(argp->xdr, readdir->rd_bmval,
 					   ARRAY_SIZE(readdir->rd_bmval)) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_remove(struct nfsd4_compoundargs *argp, struct nfsd4_remove *remove)
 {
 	return nfsd4_decode_component4(argp, &remove->rm_name, &remove->rm_namelen);
 }

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

 	status = nfsd4_decode_component4(argp, &rename->rn_sname, &rename->rn_snamelen);
 	if (status)
 		return status;
 	return nfsd4_decode_component4(argp, &rename->rn_tname, &rename->rn_tnamelen);
 }

 static __be32
 nfsd4_decode_renew(struct nfsd4_compoundargs *argp, clientid_t *clientid)
 {
 	return nfsd4_decode_clientid4(argp, clientid);
 }

 static __be32
 nfsd4_decode_secinfo(struct nfsd4_compoundargs *argp,
 		     struct nfsd4_secinfo *secinfo)
 {
 	return nfsd4_decode_component4(argp, &secinfo->si_name, &secinfo->si_namelen);
 }

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

 	status = nfsd4_decode_stateid4(argp, &setattr->sa_stateid);
 	if (status)
 		return status;
 	return nfsd4_decode_fattr4(argp, setattr->sa_bmval,
 				   ARRAY_SIZE(setattr->sa_bmval),
 				   &setattr->sa_iattr, &setattr->sa_acl,
 				   &setattr->sa_label, NULL);
 }

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

 	if (argp->minorversion >= 1)
 		return nfserr_notsupp;

 	status = nfsd4_decode_verifier4(argp, &setclientid->se_verf);
 	if (status)
 		return status;
 	status = nfsd4_decode_opaque(argp, &setclientid->se_name);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_prog) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_netid_len) < 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, setclientid->se_callback_netid_len);
 	if (!p)
 		return nfserr_bad_xdr;
 	setclientid->se_callback_netid_val = svcxdr_savemem(argp, p,
 						setclientid->se_callback_netid_len);
 	if (!setclientid->se_callback_netid_val)
 		return nfserr_jukebox;

 	if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_addr_len) < 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, setclientid->se_callback_addr_len);
 	if (!p)
 		return nfserr_bad_xdr;
 	setclientid->se_callback_addr_val = svcxdr_savemem(argp, p,
 						setclientid->se_callback_addr_len);
 	if (!setclientid->se_callback_addr_val)
 		return nfserr_jukebox;
 	if (xdr_stream_decode_u32(argp->xdr, &setclientid->se_callback_ident) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

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

 	if (argp->minorversion >= 1)
 		return nfserr_notsupp;

 	status = nfsd4_decode_clientid4(argp, &scd_c->sc_clientid);
 	if (status)
 		return status;
 	return nfsd4_decode_verifier4(argp, &scd_c->sc_confirm);
 }

 /* Also used for NVERIFY */
 static __be32
 nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify)
 {
 	__be32 *p, status;

 	status = nfsd4_decode_bitmap4(argp, verify->ve_bmval,
 				      ARRAY_SIZE(verify->ve_bmval));
 	if (status)
 		return status;

 	/* For convenience's sake, we compare raw xdr'd attributes in
 	 * nfsd4_proc_verify */

 	if (xdr_stream_decode_u32(argp->xdr, &verify->ve_attrlen) < 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, verify->ve_attrlen);
 	if (!p)
 		return nfserr_bad_xdr;
 	verify->ve_attrval = svcxdr_savemem(argp, p, verify->ve_attrlen);
 	if (!verify->ve_attrval)
 		return nfserr_jukebox;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &write->wr_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &write->wr_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &write->wr_stable_how) < 0)
 		return nfserr_bad_xdr;
 	if (write->wr_stable_how > NFS_FILE_SYNC)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &write->wr_buflen) < 0)
 		return nfserr_bad_xdr;
 	if (!xdr_stream_subsegment(argp->xdr, &write->wr_payload, write->wr_buflen))
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

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

 	if (argp->minorversion >= 1)
 		return nfserr_notsupp;

 	status = nfsd4_decode_state_owner4(argp, &rlockowner->rl_clientid,
 					   &rlockowner->rl_owner);
 	if (status)
 		return status;

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

 	return nfs_ok;
 }

 static __be32 nfsd4_decode_backchannel_ctl(struct nfsd4_compoundargs *argp, struct nfsd4_backchannel_ctl *bc)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &bc->bc_cb_program) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_cb_sec(argp, &bc->bc_cb_sec);
 }

 static __be32 nfsd4_decode_bind_conn_to_session(struct nfsd4_compoundargs *argp, struct nfsd4_bind_conn_to_session *bcts)
 {
 	u32 use_conn_in_rdma_mode;
 	__be32 status;

 	status = nfsd4_decode_sessionid4(argp, &bcts->sessionid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &bcts->dir) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &use_conn_in_rdma_mode) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_state_protect_ops(struct nfsd4_compoundargs *argp,
 			       struct nfsd4_exchange_id *exid)
 {
 	__be32 status;

 	status = nfsd4_decode_bitmap4(argp, exid->spo_must_enforce,
 				      ARRAY_SIZE(exid->spo_must_enforce));
 	if (status)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_bitmap4(argp, exid->spo_must_allow,
 				      ARRAY_SIZE(exid->spo_must_allow));
 	if (status)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 /*
  * This implementation currently does not support SP4_SSV.
  * This decoder simply skips over these arguments.
  */
 static noinline __be32
 nfsd4_decode_ssv_sp_parms(struct nfsd4_compoundargs *argp,
 			  struct nfsd4_exchange_id *exid)
 {
 	u32 count, window, num_gss_handles;
 	__be32 status;

 	/* ssp_ops */
 	status = nfsd4_decode_state_protect_ops(argp, exid);
 	if (status)
 		return status;

 	/* ssp_hash_algs<> */
 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;
 	while (count--) {
 		status = nfsd4_decode_ignored_string(argp, 0);
 		if (status)
 			return status;
 	}

 	/* ssp_encr_algs<> */
 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;
 	while (count--) {
 		status = nfsd4_decode_ignored_string(argp, 0);
 		if (status)
 			return status;
 	}

 	if (xdr_stream_decode_u32(argp->xdr, &window) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &num_gss_handles) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_state_protect4_a(struct nfsd4_compoundargs *argp,
 			      struct nfsd4_exchange_id *exid)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &exid->spa_how) < 0)
 		return nfserr_bad_xdr;
 	switch (exid->spa_how) {
 	case SP4_NONE:
 		break;
 	case SP4_MACH_CRED:
 		status = nfsd4_decode_state_protect_ops(argp, exid);
 		if (status)
 			return status;
 		break;
 	case SP4_SSV:
 		status = nfsd4_decode_ssv_sp_parms(argp, exid);
 		if (status)
 			return status;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_nfs_impl_id4(struct nfsd4_compoundargs *argp,
 			  struct nfsd4_exchange_id *exid)
 {
 	__be32 status;
 	u32 count;

 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;
 	switch (count) {
 	case 0:
 		break;
 	case 1:
 		/* Note that RFC 8881 places no length limit on
 		 * nii_domain, but this implementation permits no
 		 * more than NFS4_OPAQUE_LIMIT bytes */
 		status = nfsd4_decode_opaque(argp, &exid->nii_domain);
 		if (status)
 			return status;
 		/* Note that RFC 8881 places no length limit on
 		 * nii_name, but this implementation permits no
 		 * more than NFS4_OPAQUE_LIMIT bytes */
 		status = nfsd4_decode_opaque(argp, &exid->nii_name);
 		if (status)
 			return status;
 		status = nfsd4_decode_nfstime4(argp, &exid->nii_time);
 		if (status)
 			return status;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
 			 struct nfsd4_exchange_id *exid)
 {
 	__be32 status;

 	status = nfsd4_decode_verifier4(argp, &exid->verifier);
 	if (status)
 		return status;
 	status = nfsd4_decode_opaque(argp, &exid->clname);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &exid->flags) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_state_protect4_a(argp, exid);
 	if (status)
 		return status;
 	return nfsd4_decode_nfs_impl_id4(argp, exid);
 }

 static __be32
 nfsd4_decode_channel_attrs4(struct nfsd4_compoundargs *argp,
 			    struct nfsd4_channel_attrs *ca)
 {
 	__be32 *p;

 	p = xdr_inline_decode(argp->xdr, XDR_UNIT * 7);
 	if (!p)
 		return nfserr_bad_xdr;

 	/* headerpadsz is ignored */
 	p++;
 	ca->maxreq_sz = be32_to_cpup(p++);
 	ca->maxresp_sz = be32_to_cpup(p++);
 	ca->maxresp_cached = be32_to_cpup(p++);
 	ca->maxops = be32_to_cpup(p++);
 	ca->maxreqs = be32_to_cpup(p++);
 	ca->nr_rdma_attrs = be32_to_cpup(p);
 	switch (ca->nr_rdma_attrs) {
 	case 0:
 		break;
 	case 1:
 		if (xdr_stream_decode_u32(argp->xdr, &ca->rdma_attrs) < 0)
 			return nfserr_bad_xdr;
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

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

 	status = nfsd4_decode_clientid4(argp, &sess->clientid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &sess->seqid) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &sess->flags) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_channel_attrs4(argp, &sess->fore_channel);
 	if (status)
 		return status;
 	status = nfsd4_decode_channel_attrs4(argp, &sess->back_channel);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &sess->callback_prog) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_cb_sec(argp, &sess->cb_sec);
 	if (status)
 		return status;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_destroy_session(struct nfsd4_compoundargs *argp,
 			     struct nfsd4_destroy_session *destroy_session)
 {
 	return nfsd4_decode_sessionid4(argp, &destroy_session->sessionid);
 }

 static __be32
 nfsd4_decode_free_stateid(struct nfsd4_compoundargs *argp,
 			  struct nfsd4_free_stateid *free_stateid)
 {
 	return nfsd4_decode_stateid4(argp, &free_stateid->fr_stateid);
 }

 #ifdef CONFIG_NFSD_PNFS
 static __be32
 nfsd4_decode_getdeviceinfo(struct nfsd4_compoundargs *argp,
 		struct nfsd4_getdeviceinfo *gdev)
 {
 	__be32 status;

 	status = nfsd4_decode_deviceid4(argp, &gdev->gd_devid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &gdev->gd_layout_type) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &gdev->gd_maxcount) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_uint32_array(argp->xdr,
 					   &gdev->gd_notify_types, 1) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_layoutcommit(struct nfsd4_compoundargs *argp,
 			  struct nfsd4_layoutcommit *lcp)
 {
 	__be32 *p, status;

 	if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_seg.offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_seg.length) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_bool(argp->xdr, &lcp->lc_reclaim) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_stateid4(argp, &lcp->lc_sid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &lcp->lc_newoffset) < 0)
 		return nfserr_bad_xdr;
 	if (lcp->lc_newoffset) {
 		if (xdr_stream_decode_u64(argp->xdr, &lcp->lc_last_wr) < 0)
 			return nfserr_bad_xdr;
 	} else
 		lcp->lc_last_wr = 0;
 	p = xdr_inline_decode(argp->xdr, XDR_UNIT);
 	if (!p)
 		return nfserr_bad_xdr;
 	if (xdr_item_is_present(p)) {
 		status = nfsd4_decode_nfstime4(argp, &lcp->lc_mtime);
 		if (status)
 			return status;
 	} else {
 		lcp->lc_mtime.tv_nsec = UTIME_NOW;
 	}
 	return nfsd4_decode_layoutupdate4(argp, lcp);
 }

 static __be32
 nfsd4_decode_layoutget(struct nfsd4_compoundargs *argp,
 		struct nfsd4_layoutget *lgp)
 {
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_signal) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_layout_type) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_seg.iomode) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_seg.offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_seg.length) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &lgp->lg_minlength) < 0)
 		return nfserr_bad_xdr;
 	status = nfsd4_decode_stateid4(argp, &lgp->lg_sid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u32(argp->xdr, &lgp->lg_maxcount) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_layoutreturn(struct nfsd4_compoundargs *argp,
 		struct nfsd4_layoutreturn *lrp)
 {
 	if (xdr_stream_decode_bool(argp->xdr, &lrp->lr_reclaim) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_layout_type) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &lrp->lr_seg.iomode) < 0)
 		return nfserr_bad_xdr;
 	return nfsd4_decode_layoutreturn4(argp, lrp);
 }
 #endif /* CONFIG_NFSD_PNFS */

 static __be32 nfsd4_decode_secinfo_no_name(struct nfsd4_compoundargs *argp,
 					   struct nfsd4_secinfo_no_name *sin)
 {
 	if (xdr_stream_decode_u32(argp->xdr, &sin->sin_style) < 0)
 		return nfserr_bad_xdr;
 	return nfs_ok;
 }

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

 	status = nfsd4_decode_sessionid4(argp, &seq->sessionid);
 	if (status)
 		return status;
 	p = xdr_inline_decode(argp->xdr, XDR_UNIT * 4);
 	if (!p)
 		return nfserr_bad_xdr;
 	seq->seqid = be32_to_cpup(p++);
 	seq->slotid = be32_to_cpup(p++);
 	seq->maxslots = be32_to_cpup(p++);
 	seq->cachethis = be32_to_cpup(p);

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_test_stateid(struct nfsd4_compoundargs *argp, struct nfsd4_test_stateid *test_stateid)
 {
 	struct nfsd4_test_stateid_id *stateid;
 	__be32 status;
 	u32 i;

 	if (xdr_stream_decode_u32(argp->xdr, &test_stateid->ts_num_ids) < 0)
 		return nfserr_bad_xdr;

 	INIT_LIST_HEAD(&test_stateid->ts_stateid_list);
 	for (i = 0; i < test_stateid->ts_num_ids; i++) {
 		stateid = svcxdr_tmpalloc(argp, sizeof(*stateid));
 		if (!stateid)
 			return nfserrno(-ENOMEM);	/* XXX: not jukebox? */
 		INIT_LIST_HEAD(&stateid->ts_id_list);
 		list_add_tail(&stateid->ts_id_list, &test_stateid->ts_stateid_list);
 		status = nfsd4_decode_stateid4(argp, &stateid->ts_id_stateid);
 		if (status)
 			return status;
 	}

 	return nfs_ok;
 }

 static __be32 nfsd4_decode_destroy_clientid(struct nfsd4_compoundargs *argp,
 					    struct nfsd4_destroy_clientid *dc)
 {
 	return nfsd4_decode_clientid4(argp, &dc->clientid);
 }

 static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp,
 					    struct nfsd4_reclaim_complete *rc)
 {
 	if (xdr_stream_decode_bool(argp->xdr, &rc->rca_one_fs) < 0)
 		return nfserr_bad_xdr;
 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_fallocate(struct nfsd4_compoundargs *argp,
 		       struct nfsd4_fallocate *fallocate)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &fallocate->falloc_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &fallocate->falloc_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &fallocate->falloc_length) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32 nfsd4_decode_nl4_server(struct nfsd4_compoundargs *argp,
 				      struct nl4_server *ns)
 {
 	struct nfs42_netaddr *naddr;
 	__be32 *p;

 	if (xdr_stream_decode_u32(argp->xdr, &ns->nl4_type) < 0)
 		return nfserr_bad_xdr;

 	/* currently support for 1 inter-server source server */
 	switch (ns->nl4_type) {
 	case NL4_NETADDR:
 		naddr = &ns->u.nl4_addr;

 		if (xdr_stream_decode_u32(argp->xdr, &naddr->netid_len) < 0)
 			return nfserr_bad_xdr;
 		if (naddr->netid_len > RPCBIND_MAXNETIDLEN)
 			return nfserr_bad_xdr;

 		p = xdr_inline_decode(argp->xdr, naddr->netid_len);
 		if (!p)
 			return nfserr_bad_xdr;
 		memcpy(naddr->netid, p, naddr->netid_len);

 		if (xdr_stream_decode_u32(argp->xdr, &naddr->addr_len) < 0)
 			return nfserr_bad_xdr;
 		if (naddr->addr_len > RPCBIND_MAXUADDRLEN)
 			return nfserr_bad_xdr;

 		p = xdr_inline_decode(argp->xdr, naddr->addr_len);
 		if (!p)
 			return nfserr_bad_xdr;
 		memcpy(naddr->addr, p, naddr->addr_len);
 		break;
 	default:
 		return nfserr_bad_xdr;
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_copy(struct nfsd4_compoundargs *argp, struct nfsd4_copy *copy)
 {
 	struct nl4_server *ns_dummy;
 	u32 consecutive, i, count;
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &copy->cp_src_stateid);
 	if (status)
 		return status;
 	status = nfsd4_decode_stateid4(argp, &copy->cp_dst_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &copy->cp_src_pos) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &copy->cp_dst_pos) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &copy->cp_count) < 0)
 		return nfserr_bad_xdr;
 	/* ca_consecutive: we always do consecutive copies */
 	if (xdr_stream_decode_u32(argp->xdr, &consecutive) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &copy->cp_synchronous) < 0)
 		return nfserr_bad_xdr;

 	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
 		return nfserr_bad_xdr;
 	copy->cp_intra = false;
 	if (count == 0) { /* intra-server copy */
 		copy->cp_intra = true;
 		return nfs_ok;
 	}

 	/* decode all the supplied server addresses but use only the first */
 	status = nfsd4_decode_nl4_server(argp, &copy->cp_src);
 	if (status)
 		return status;

 	ns_dummy = kmalloc(sizeof(struct nl4_server), GFP_KERNEL);
 	if (ns_dummy == NULL)
 		return nfserrno(-ENOMEM);	/* XXX: jukebox? */
 	for (i = 0; i < count - 1; i++) {
 		status = nfsd4_decode_nl4_server(argp, ns_dummy);
 		if (status) {
 			kfree(ns_dummy);
 			return status;
 		}
 	}
 	kfree(ns_dummy);

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_copy_notify(struct nfsd4_compoundargs *argp,
 			 struct nfsd4_copy_notify *cn)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &cn->cpn_src_stateid);
 	if (status)
 		return status;
 	return nfsd4_decode_nl4_server(argp, &cn->cpn_dst);
 }

 static __be32
 nfsd4_decode_offload_status(struct nfsd4_compoundargs *argp,
 			    struct nfsd4_offload_status *os)
 {
 	return nfsd4_decode_stateid4(argp, &os->stateid);
 }

 static __be32
 nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &seek->seek_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &seek->seek_offset) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u32(argp->xdr, &seek->seek_whence) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_clone(struct nfsd4_compoundargs *argp, struct nfsd4_clone *clone)
 {
 	__be32 status;

 	status = nfsd4_decode_stateid4(argp, &clone->cl_src_stateid);
 	if (status)
 		return status;
 	status = nfsd4_decode_stateid4(argp, &clone->cl_dst_stateid);
 	if (status)
 		return status;
 	if (xdr_stream_decode_u64(argp->xdr, &clone->cl_src_pos) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &clone->cl_dst_pos) < 0)
 		return nfserr_bad_xdr;
 	if (xdr_stream_decode_u64(argp->xdr, &clone->cl_count) < 0)
 		return nfserr_bad_xdr;

 	return nfs_ok;
 }

 /*
  * XDR data that is more than PAGE_SIZE in size is normally part of a
  * read or write. However, the size of extended attributes is limited
  * by the maximum request size, and then further limited by the underlying
  * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
  * is 64k). Since there is no kvec- or page-based interface to xattrs,
  * and we're not dealing with contiguous pages, we need to do some copying.
  */

 /*
  * Decode data into buffer.
  */
 static __be32
 nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct xdr_buf *xdr,
 		       char **bufp, u32 buflen)
 {
 	struct page **pages = xdr->pages;
 	struct kvec *head = xdr->head;
 	char *tmp, *dp;
 	u32 len;

 	if (buflen <= head->iov_len) {
 		/*
 		 * We're in luck, the head has enough space. Just return
 		 * the head, no need for copying.
 		 */
 		*bufp = head->iov_base;
 		return 0;
 	}

 	tmp = svcxdr_tmpalloc(argp, buflen);
 	if (tmp == NULL)
 		return nfserr_jukebox;

 	dp = tmp;
 	memcpy(dp, head->iov_base, head->iov_len);
 	buflen -= head->iov_len;
 	dp += head->iov_len;

 	while (buflen > 0) {
 		len = min_t(u32, buflen, PAGE_SIZE);
 		memcpy(dp, page_address(*pages), len);

 		buflen -= len;
 		dp += len;
 		pages++;
 	}

 	*bufp = tmp;
 	return 0;
 }

 /*
  * Get a user extended attribute name from the XDR buffer.
  * It will not have the "user." prefix, so prepend it.
  * Lastly, check for nul characters in the name.
  */
 static __be32
 nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
 {
 	char *name, *sp, *dp;
 	u32 namelen, cnt;
 	__be32 *p;

 	if (xdr_stream_decode_u32(argp->xdr, &namelen) < 0)
 		return nfserr_bad_xdr;
 	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
 		return nfserr_nametoolong;
 	if (namelen == 0)
 		return nfserr_bad_xdr;
 	p = xdr_inline_decode(argp->xdr, namelen);
 	if (!p)
 		return nfserr_bad_xdr;
 	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
 	if (!name)
 		return nfserr_jukebox;
 	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);

 	/*
 	 * Copy the extended attribute name over while checking for 0
 	 * characters.
 	 */
 	sp = (char *)p;
 	dp = name + XATTR_USER_PREFIX_LEN;
 	cnt = namelen;

 	while (cnt-- > 0) {
 		if (*sp == '\0')
 			return nfserr_bad_xdr;
 		*dp++ = *sp++;
 	}
 	*dp = '\0';

 	*namep = name;

 	return nfs_ok;
 }

 /*
  * A GETXATTR op request comes without a length specifier. We just set the
  * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
  * channel reply size. nfsd_getxattr will probe the length of the xattr,
  * check it against getxa_len, and allocate + return the value.
  */
 static __be32
 nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
 		      struct nfsd4_getxattr *getxattr)
 {
 	__be32 status;
 	u32 maxcount;

 	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
 	if (status)
 		return status;

 	maxcount = svc_max_payload(argp->rqstp);
 	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);

 	getxattr->getxa_len = maxcount;

 	return status;
 }

 static __be32
 nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
 		      struct nfsd4_setxattr *setxattr)
 {
 	u32 flags, maxcount, size;
 	__be32 status;

 	if (xdr_stream_decode_u32(argp->xdr, &flags) < 0)
 		return nfserr_bad_xdr;

 	if (flags > SETXATTR4_REPLACE)
 		return nfserr_inval;
 	setxattr->setxa_flags = flags;

 	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
 	if (status)
 		return status;

 	maxcount = svc_max_payload(argp->rqstp);
 	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);

 	if (xdr_stream_decode_u32(argp->xdr, &size) < 0)
 		return nfserr_bad_xdr;
 	if (size > maxcount)
 		return nfserr_xattr2big;

 	setxattr->setxa_len = size;
 	if (size > 0) {
 		struct xdr_buf payload;

 		if (!xdr_stream_subsegment(argp->xdr, &payload, size))
 			return nfserr_bad_xdr;
 		status = nfsd4_vbuf_from_vector(argp, &payload,
 						&setxattr->setxa_buf, size);
 	}

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
 			struct nfsd4_listxattrs *listxattrs)
 {
 	u32 maxcount;

 	if (xdr_stream_decode_u64(argp->xdr, &listxattrs->lsxa_cookie) < 0)
 		return nfserr_bad_xdr;

 	/*
 	 * If the cookie  is too large to have even one user.x attribute
 	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
 	 */
 	if (listxattrs->lsxa_cookie >=
 	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
 		return nfserr_badcookie;

 	if (xdr_stream_decode_u32(argp->xdr, &maxcount) < 0)
 		return nfserr_bad_xdr;
 	if (maxcount < 8)
 		/* Always need at least 2 words (length and one character) */
 		return nfserr_inval;

 	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
 	listxattrs->lsxa_maxcount = maxcount;

 	return nfs_ok;
 }

 static __be32
 nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
 			 struct nfsd4_removexattr *removexattr)
 {
 	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
 }

 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 const 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_putpubfh,
 	[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,

 	/* new operations for NFSv4.1 */
 	[OP_BACKCHANNEL_CTL]	= (nfsd4_dec)nfsd4_decode_backchannel_ctl,
 	[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_free_stateid,
 	[OP_GET_DIR_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
 #ifdef CONFIG_NFSD_PNFS
 	[OP_GETDEVICEINFO]	= (nfsd4_dec)nfsd4_decode_getdeviceinfo,
 	[OP_GETDEVICELIST]	= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_LAYOUTCOMMIT]	= (nfsd4_dec)nfsd4_decode_layoutcommit,
 	[OP_LAYOUTGET]		= (nfsd4_dec)nfsd4_decode_layoutget,
 	[OP_LAYOUTRETURN]	= (nfsd4_dec)nfsd4_decode_layoutreturn,
 #else
 	[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,
 #endif
 	[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_test_stateid,
 	[OP_WANT_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_DESTROY_CLIENTID]	= (nfsd4_dec)nfsd4_decode_destroy_clientid,
 	[OP_RECLAIM_COMPLETE]	= (nfsd4_dec)nfsd4_decode_reclaim_complete,

 	/* new operations for NFSv4.2 */
 	[OP_ALLOCATE]		= (nfsd4_dec)nfsd4_decode_fallocate,
 	[OP_COPY]		= (nfsd4_dec)nfsd4_decode_copy,
 	[OP_COPY_NOTIFY]	= (nfsd4_dec)nfsd4_decode_copy_notify,
 	[OP_DEALLOCATE]		= (nfsd4_dec)nfsd4_decode_fallocate,
 	[OP_IO_ADVISE]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_LAYOUTERROR]	= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_LAYOUTSTATS]	= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_OFFLOAD_CANCEL]	= (nfsd4_dec)nfsd4_decode_offload_status,
 	[OP_OFFLOAD_STATUS]	= (nfsd4_dec)nfsd4_decode_offload_status,
 	[OP_READ_PLUS]		= (nfsd4_dec)nfsd4_decode_read,
 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
 	/* RFC 8276 extended atributes operations */
 	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
 	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
 	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
 	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
 };

 static inline bool
 nfsd4_opnum_in_range(struct nfsd4_compoundargs *argp, struct nfsd4_op *op)
 {
 	if (op->opnum < FIRST_NFS4_OP)
 		return false;
 	else if (argp->minorversion == 0 && op->opnum > LAST_NFS40_OP)
 		return false;
 	else if (argp->minorversion == 1 && op->opnum > LAST_NFS41_OP)
 		return false;
 	else if (argp->minorversion == 2 && op->opnum > LAST_NFS42_OP)
 		return false;
 	return true;
 }

 static int
 nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
 {
 	struct nfsd4_op *op;
 	bool cachethis = false;
 	int auth_slack= argp->rqstp->rq_auth_slack;
 	int max_reply = auth_slack + 8; /* opcnt, status */
 	int readcount = 0;
 	int readbytes = 0;
 	__be32 *p;
 	int i;

 	if (xdr_stream_decode_u32(argp->xdr, &argp->taglen) < 0)
 		return 0;
 	max_reply += XDR_UNIT;
 	argp->tag = NULL;
 	if (unlikely(argp->taglen)) {
 		if (argp->taglen > NFSD4_MAX_TAGLEN)
 			return 0;
 		p = xdr_inline_decode(argp->xdr, argp->taglen);
 		if (!p)
 			return 0;
 		argp->tag = svcxdr_savemem(argp, p, argp->taglen);
 		if (!argp->tag)
 			return 0;
 		max_reply += xdr_align_size(argp->taglen);
 	}

 	if (xdr_stream_decode_u32(argp->xdr, &argp->minorversion) < 0)
 		return 0;
 	if (xdr_stream_decode_u32(argp->xdr, &argp->client_opcnt) < 0)
 		return 0;

 	argp->opcnt = min_t(u32, argp->client_opcnt,
 			    NFSD_MAX_OPS_PER_COMPOUND);

 	if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
 		argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
 		if (!argp->ops) {
 			argp->ops = argp->iops;
 			dprintk("nfsd: couldn't allocate room for COMPOUND\n");
 			return 0;
 		}
 	}

 	if (argp->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
 		argp->opcnt = 0;

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

 		if (xdr_stream_decode_u32(argp->xdr, &op->opnum) < 0)
 			return 0;
 		if (nfsd4_opnum_in_range(argp, op)) {
 			op->status = nfsd4_dec_ops[op->opnum](argp, &op->u);
 			if (op->status != nfs_ok)
 				trace_nfsd_compound_decode_err(argp->rqstp,
 							       argp->opcnt, i,
 							       op->opnum,
 							       op->status);
 		} else {
 			op->opnum = OP_ILLEGAL;
 			op->status = nfserr_op_illegal;
 		}
 		op->opdesc = OPDESC(op);
 		/*
 		 * We'll try to cache the result in the DRC if any one
 		 * op in the compound wants to be cached:
 		 */
 		cachethis |= nfsd4_cache_this_op(op);

 		if (op->opnum == OP_READ || op->opnum == OP_READ_PLUS) {
 			readcount++;
 			readbytes += nfsd4_max_reply(argp->rqstp, op);
 		} else
 			max_reply += nfsd4_max_reply(argp->rqstp, op);
 		/*
 		 * OP_LOCK and OP_LOCKT may return a conflicting lock.
 		 * (Special case because it will just skip encoding this
 		 * if it runs out of xdr buffer space, and it is the only
 		 * operation that behaves this way.)
 		 */
 		if (op->opnum == OP_LOCK || op->opnum == OP_LOCKT)
 			max_reply += NFS4_OPAQUE_LIMIT;

 		if (op->status) {
 			argp->opcnt = i+1;
 			break;
 		}
 	}
 	/* Sessions make the DRC unnecessary: */
 	if (argp->minorversion)
 		cachethis = false;
 	svc_reserve(argp->rqstp, max_reply + readbytes);
 	argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE;

 	if (readcount > 1 || max_reply > PAGE_SIZE - auth_slack)
 		clear_bit(RQ_SPLICE_OK, &argp->rqstp->rq_flags);

 	return 1;
 }

 static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode,
 			     struct svc_export *exp)
 {
 	if (exp->ex_flags & NFSEXP_V4ROOT) {
 		*p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time));
 		*p++ = 0;
 	} else
 		p = xdr_encode_hyper(p, nfsd4_change_attribute(stat, inode));
 	return p;
 }

 /*
  * ctime (in NFSv4, time_metadata) is not writeable, and the client
  * doesn't really care what resolution could theoretically be stored by
  * the filesystem.
  *
  * The client cares how close together changes can be while still
  * guaranteeing ctime changes.  For most filesystems (which have
  * timestamps with nanosecond fields) that is limited by the resolution
  * of the time returned from current_time() (which I'm assuming to be
  * 1/HZ).
  */
 static __be32 *encode_time_delta(__be32 *p, struct inode *inode)
 {
 	struct timespec64 ts;
 	u32 ns;

 	ns = max_t(u32, NSEC_PER_SEC/HZ, inode->i_sb->s_time_gran);
 	ts = ns_to_timespec64(ns);

 	p = xdr_encode_hyper(p, ts.tv_sec);
 	*p++ = cpu_to_be32(ts.tv_nsec);

 	return p;
 }

 static __be32 *encode_cinfo(__be32 *p, struct nfsd4_change_info *c)
 {
 	*p++ = cpu_to_be32(c->atomic);
 	p = xdr_encode_hyper(p, c->before_change);
 	p = xdr_encode_hyper(p, c->after_change);
 	return p;
 }

 /* Encode as an array of strings the string given with components
  * separated @sep, escaped with esc_enter and esc_exit.
  */
 static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
 					  char *components, char esc_enter,
 					  char esc_exit)
 {
 	__be32 *p;
 	__be32 pathlen;
 	int pathlen_offset;
 	int strlen, count=0;
 	char *str, *end, *next;

 	dprintk("nfsd4_encode_components(%s)\n", components);

 	pathlen_offset = xdr->buf->len;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	p++; /* We will fill this in with @count later */

 	end = str = components;
 	while (*end) {
 		bool found_esc = false;

 		/* try to parse as esc_start, ..., esc_end, sep */
 		if (*str == esc_enter) {
 			for (; *end && (*end != esc_exit); end++)
 				/* find esc_exit or end of string */;
 			next = end + 1;
 			if (*end && (!*next || *next == sep)) {
 				str++;
 				found_esc = true;
 			}
 		}

 		if (!found_esc)
 			for (; *end && (*end != sep); end++)
 				/* find sep or end of string */;

 		strlen = end - str;
 		if (strlen) {
 			p = xdr_reserve_space(xdr, strlen + 4);
 			if (!p)
 				return nfserr_resource;
 			p = xdr_encode_opaque(p, str, strlen);
 			count++;
 		}
 		else
 			end++;
 		if (found_esc)
 			end = next;

 		str = end;
 	}
 	pathlen = htonl(count);
 	write_bytes_to_xdr_buf(xdr->buf, pathlen_offset, &pathlen, 4);
 	return 0;
 }

 /* Encode as an array of strings the string given with components
  * separated @sep.
  */
 static __be32 nfsd4_encode_components(struct xdr_stream *xdr, char sep,
 				      char *components)
 {
 	return nfsd4_encode_components_esc(xdr, sep, components, 0, 0);
 }

 /*
  * encode a location element of a fs_locations structure
  */
 static __be32 nfsd4_encode_fs_location4(struct xdr_stream *xdr,
 					struct nfsd4_fs_location *location)
 {
 	__be32 status;

 	status = nfsd4_encode_components_esc(xdr, ':', location->hosts,
 						'[', ']');
 	if (status)
 		return status;
 	status = nfsd4_encode_components(xdr, '/', location->path);
 	if (status)
 		return status;
 	return 0;
 }

 /*
  * Encode a path in RFC3530 'pathname4' format
  */
 static __be32 nfsd4_encode_path(struct xdr_stream *xdr,
 				const struct path *root,
 				const struct path *path)
 {
 	struct path cur = *path;
 	__be32 *p;
 	struct dentry **components = NULL;
 	unsigned int ncomponents = 0;
 	__be32 err = nfserr_jukebox;

 	dprintk("nfsd4_encode_components(");

 	path_get(&cur);
 	/* First walk the path up to the nfsd root, and store the
 	 * dentries/path components in an array.
 	 */
 	for (;;) {
 		if (path_equal(&cur, root))
 			break;
 		if (cur.dentry == cur.mnt->mnt_root) {
 			if (follow_up(&cur))
 				continue;
 			goto out_free;
 		}
 		if ((ncomponents & 15) == 0) {
 			struct dentry **new;
 			new = krealloc(components,
 					sizeof(*new) * (ncomponents + 16),
 					GFP_KERNEL);
 			if (!new)
 				goto out_free;
 			components = new;
 		}
 		components[ncomponents++] = cur.dentry;
 		cur.dentry = dget_parent(cur.dentry);
 	}
 	err = nfserr_resource;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		goto out_free;
 	*p++ = cpu_to_be32(ncomponents);

 	while (ncomponents) {
 		struct dentry *dentry = components[ncomponents - 1];
 		unsigned int len;

 		spin_lock(&dentry->d_lock);
 		len = dentry->d_name.len;
 		p = xdr_reserve_space(xdr, len + 4);
 		if (!p) {
 			spin_unlock(&dentry->d_lock);
 			goto out_free;
 		}
 		p = xdr_encode_opaque(p, dentry->d_name.name, len);
 		dprintk("/%pd", dentry);
 		spin_unlock(&dentry->d_lock);
 		dput(dentry);
 		ncomponents--;
 	}

 	err = 0;
 out_free:
 	dprintk(")\n");
 	while (ncomponents)
 		dput(components[--ncomponents]);
 	kfree(components);
 	path_put(&cur);
 	return err;
 }

 static __be32 nfsd4_encode_fsloc_fsroot(struct xdr_stream *xdr,
 			struct svc_rqst *rqstp, const struct path *path)
 {
 	struct svc_export *exp_ps;
 	__be32 res;

 	exp_ps = rqst_find_fsidzero_export(rqstp);
 	if (IS_ERR(exp_ps))
 		return nfserrno(PTR_ERR(exp_ps));
 	res = nfsd4_encode_path(xdr, &exp_ps->ex_path, path);
 	exp_put(exp_ps);
 	return res;
 }

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

 	status = nfsd4_encode_fsloc_fsroot(xdr, rqstp, &exp->ex_path);
 	if (status)
 		return status;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(fslocs->locations_count);
 	for (i=0; i<fslocs->locations_count; i++) {
 		status = nfsd4_encode_fs_location4(xdr, &fslocs->locations[i]);
 		if (status)
 			return status;
 	}
 	return 0;
 }

 static u32 nfs4_file_type(umode_t mode)
 {
 	switch (mode & S_IFMT) {
 	case S_IFIFO:	return NF4FIFO;
 	case S_IFCHR:	return NF4CHR;
 	case S_IFDIR:	return NF4DIR;
 	case S_IFBLK:	return NF4BLK;
 	case S_IFLNK:	return NF4LNK;
 	case S_IFREG:	return NF4REG;
 	case S_IFSOCK:	return NF4SOCK;
 	default:	return NF4BAD;
 	}
 }

 static inline __be32
 nfsd4_encode_aclname(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 		     struct nfs4_ace *ace)
 {
 	if (ace->whotype != NFS4_ACL_WHO_NAMED)
 		return nfs4_acl_write_who(xdr, ace->whotype);
 	else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
 		return nfsd4_encode_group(xdr, rqstp, ace->who_gid);
 	else
 		return nfsd4_encode_user(xdr, rqstp, ace->who_uid);
 }

 static inline __be32
 nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
 {
 	__be32		*p;
 	unsigned long	i = hweight_long(layout_types);

 	p = xdr_reserve_space(xdr, 4 + 4 * i);
 	if (!p)
 		return nfserr_resource;

 	*p++ = cpu_to_be32(i);

 	for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
 		if (layout_types & (1 << i))
 			*p++ = cpu_to_be32(i);

 	return 0;
 }

 #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
 #define WORD2_ABSENT_FS_ATTRS 0

 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 			    void *context, int len)
 {
 	__be32 *p;

 	p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
 	if (!p)
 		return nfserr_resource;

 	/*
 	 * For now we use a 0 here to indicate the null translation; in
 	 * the future we may place a call to translation code here.
 	 */
 	*p++ = cpu_to_be32(0); /* lfs */
 	*p++ = cpu_to_be32(0); /* pi */
 	p = xdr_encode_opaque(p, context, len);
 	return 0;
 }
 #else
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 			    void *context, int len)
 { return 0; }
 #endif

 static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *bmval2, 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;
 	*bmval2 &= WORD2_ABSENT_FS_ATTRS;
 	return 0;
 }


 static int get_parent_attributes(struct svc_export *exp, struct kstat *stat)
 {
 	struct path path = exp->ex_path;
 	int err;

 	path_get(&path);
 	while (follow_up(&path)) {
 		if (path.dentry != path.mnt->mnt_root)
 			break;
 	}
 	err = vfs_getattr(&path, stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
 	path_put(&path);
 	return err;
 }

 static __be32
 nfsd4_encode_bitmap(struct xdr_stream *xdr, u32 bmval0, u32 bmval1, u32 bmval2)
 {
 	__be32 *p;

 	if (bmval2) {
 		p = xdr_reserve_space(xdr, 16);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(3);
 		*p++ = cpu_to_be32(bmval0);
 		*p++ = cpu_to_be32(bmval1);
 		*p++ = cpu_to_be32(bmval2);
 	} else if (bmval1) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(2);
 		*p++ = cpu_to_be32(bmval0);
 		*p++ = cpu_to_be32(bmval1);
 	} else {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 		*p++ = cpu_to_be32(bmval0);
 	}

 	return 0;
 out_resource:
 	return nfserr_resource;
 }

 /*
  * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
  * ourselves.
  */
 static __be32
 nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 		struct svc_export *exp,
 		struct dentry *dentry, 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 = NULL;
 	struct kstatfs statfs;
 	__be32 *p;
 	int starting_len = xdr->buf->len;
 	int attrlen_offset;
 	__be32 attrlen;
 	u32 dummy;
 	u64 dummy64;
 	u32 rdattr_err = 0;
 	__be32 status;
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	void *context = NULL;
 	int contextlen;
 #endif
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	u32 minorversion = resp->cstate.minorversion;
 	struct path path = {
 		.mnt	= exp->ex_path.mnt,
 		.dentry	= dentry,
 	};
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

 	BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
 	BUG_ON(!nfsd_attrs_supported(minorversion, bmval));

 	if (exp->ex_fslocs.migrated) {
 		status = fattr_handle_absent_fs(&bmval0, &bmval1, &bmval2, &rdattr_err);
 		if (status)
 			goto out;
 	}

 	err = vfs_getattr(&path, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
 	if (err)
 		goto out_nfserr;
 	if ((bmval0 & (FATTR4_WORD0_FILES_AVAIL | 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) {
 		tempfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
 		status = nfserr_jukebox;
 		if (!tempfh)
 			goto out;
 		fh_init(tempfh, NFS4_FHSIZE);
 		status = fh_compose(tempfh, exp, dentry, NULL);
 		if (status)
 			goto out;
 		fhp = tempfh;
 	}
 	if (bmval0 & FATTR4_WORD0_ACL) {
 		err = nfsd4_get_nfs4_acl(rqstp, dentry, &acl);
 		if (err == -EOPNOTSUPP)
 			bmval0 &= ~FATTR4_WORD0_ACL;
 		else if (err == -EINVAL) {
 			status = nfserr_attrnotsupp;
 			goto out;
 		} else if (err != 0)
 			goto out_nfserr;
 	}

 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if ((bmval2 & FATTR4_WORD2_SECURITY_LABEL) ||
 	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
 			err = security_inode_getsecctx(d_inode(dentry),
 						&context, &contextlen);
 		else
 			err = -EOPNOTSUPP;
 		contextsupport = (err == 0);
 		if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
 			if (err == -EOPNOTSUPP)
 				bmval2 &= ~FATTR4_WORD2_SECURITY_LABEL;
 			else if (err)
 				goto out_nfserr;
 		}
 	}
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */

 	status = nfsd4_encode_bitmap(xdr, bmval0, bmval1, bmval2);
 	if (status)
 		goto out;

 	attrlen_offset = xdr->buf->len;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		goto out_resource;
 	p++;                /* to be backfilled later */

 	if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		u32 supp[3];

 		memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));

 		if (!IS_POSIXACL(dentry->d_inode))
 			supp[0] &= ~FATTR4_WORD0_ACL;
 		if (!contextsupport)
 			supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
 		if (!supp[2]) {
 			p = xdr_reserve_space(xdr, 12);
 			if (!p)
 				goto out_resource;
 			*p++ = cpu_to_be32(2);
 			*p++ = cpu_to_be32(supp[0]);
 			*p++ = cpu_to_be32(supp[1]);
 		} else {
 			p = xdr_reserve_space(xdr, 16);
 			if (!p)
 				goto out_resource;
 			*p++ = cpu_to_be32(3);
 			*p++ = cpu_to_be32(supp[0]);
 			*p++ = cpu_to_be32(supp[1]);
 			*p++ = cpu_to_be32(supp[2]);
 		}
 	}
 	if (bmval0 & FATTR4_WORD0_TYPE) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		dummy = nfs4_file_type(stat.mode);
 		if (dummy == NF4BAD) {
 			status = nfserr_serverfault;
 			goto out;
 		}
 		*p++ = cpu_to_be32(dummy);
 	}
 	if (bmval0 & FATTR4_WORD0_FH_EXPIRE_TYPE) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
 			*p++ = cpu_to_be32(NFS4_FH_PERSISTENT);
 		else
 			*p++ = cpu_to_be32(NFS4_FH_PERSISTENT|
 						NFS4_FH_VOL_RENAME);
 	}
 	if (bmval0 & FATTR4_WORD0_CHANGE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = encode_change(p, &stat, d_inode(dentry), exp);
 	}
 	if (bmval0 & FATTR4_WORD0_SIZE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, stat.size);
 	}
 	if (bmval0 & FATTR4_WORD0_LINK_SUPPORT) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_SYMLINK_SUPPORT) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_NAMED_ATTR) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(0);
 	}
 	if (bmval0 & FATTR4_WORD0_FSID) {
 		p = xdr_reserve_space(xdr, 16);
 		if (!p)
 			goto out_resource;
 		if (exp->ex_fslocs.migrated) {
 			p = xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MAJOR);
 			p = xdr_encode_hyper(p, NFS4_REFERRAL_FSID_MINOR);
 		} else switch(fsid_source(fhp)) {
 		case FSIDSOURCE_FSID:
 			p = xdr_encode_hyper(p, (u64)exp->ex_fsid);
 			p = xdr_encode_hyper(p, (u64)0);
 			break;
 		case FSIDSOURCE_DEV:
 			*p++ = cpu_to_be32(0);
 			*p++ = cpu_to_be32(MAJOR(stat.dev));
 			*p++ = cpu_to_be32(0);
 			*p++ = cpu_to_be32(MINOR(stat.dev));
 			break;
 		case FSIDSOURCE_UUID:
 			p = xdr_encode_opaque_fixed(p, exp->ex_uuid,
 								EX_UUID_LEN);
 			break;
 		}
 	}
 	if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(0);
 	}
 	if (bmval0 & FATTR4_WORD0_LEASE_TIME) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(nn->nfsd4_lease);
 	}
 	if (bmval0 & FATTR4_WORD0_RDATTR_ERROR) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(rdattr_err);
 	}
 	if (bmval0 & FATTR4_WORD0_ACL) {
 		struct nfs4_ace *ace;

 		if (acl == NULL) {
 			p = xdr_reserve_space(xdr, 4);
 			if (!p)
 				goto out_resource;

 			*p++ = cpu_to_be32(0);
 			goto out_acl;
 		}
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(acl->naces);

 		for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
 			p = xdr_reserve_space(xdr, 4*3);
 			if (!p)
 				goto out_resource;
 			*p++ = cpu_to_be32(ace->type);
 			*p++ = cpu_to_be32(ace->flag);
 			*p++ = cpu_to_be32(ace->access_mask &
 							NFS4_ACE_MASK_ALL);
 			status = nfsd4_encode_aclname(xdr, rqstp, ace);
 			if (status)
 				goto out;
 		}
 	}
 out_acl:
 	if (bmval0 & FATTR4_WORD0_ACLSUPPORT) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(IS_POSIXACL(dentry->d_inode) ?
 			ACL4_SUPPORT_ALLOW_ACL|ACL4_SUPPORT_DENY_ACL : 0);
 	}
 	if (bmval0 & FATTR4_WORD0_CANSETTIME) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(0);
 	}
 	if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_CHOWN_RESTRICTED) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_FILEHANDLE) {
 		p = xdr_reserve_space(xdr, fhp->fh_handle.fh_size + 4);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_opaque(p, &fhp->fh_handle.fh_base,
 					fhp->fh_handle.fh_size);
 	}
 	if (bmval0 & FATTR4_WORD0_FILEID) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, stat.ino);
 	}
 	if (bmval0 & FATTR4_WORD0_FILES_AVAIL) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (u64) statfs.f_ffree);
 	}
 	if (bmval0 & FATTR4_WORD0_FILES_FREE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (u64) statfs.f_ffree);
 	}
 	if (bmval0 & FATTR4_WORD0_FILES_TOTAL) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (u64) statfs.f_files);
 	}
 	if (bmval0 & FATTR4_WORD0_FS_LOCATIONS) {
 		status = nfsd4_encode_fs_locations(xdr, rqstp, exp);
 		if (status)
 			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_HOMOGENEOUS) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval0 & FATTR4_WORD0_MAXFILESIZE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, exp->ex_path.mnt->mnt_sb->s_maxbytes);
 	}
 	if (bmval0 & FATTR4_WORD0_MAXLINK) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(255);
 	}
 	if (bmval0 & FATTR4_WORD0_MAXNAME) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(statfs.f_namelen);
 	}
 	if (bmval0 & FATTR4_WORD0_MAXREAD) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (u64) svc_max_payload(rqstp));
 	}
 	if (bmval0 & FATTR4_WORD0_MAXWRITE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (u64) svc_max_payload(rqstp));
 	}
 	if (bmval1 & FATTR4_WORD1_MODE) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(stat.mode & S_IALLUGO);
 	}
 	if (bmval1 & FATTR4_WORD1_NO_TRUNC) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(1);
 	}
 	if (bmval1 & FATTR4_WORD1_NUMLINKS) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(stat.nlink);
 	}
 	if (bmval1 & FATTR4_WORD1_OWNER) {
 		status = nfsd4_encode_user(xdr, rqstp, stat.uid);
 		if (status)
 			goto out;
 	}
 	if (bmval1 & FATTR4_WORD1_OWNER_GROUP) {
 		status = nfsd4_encode_group(xdr, rqstp, stat.gid);
 		if (status)
 			goto out;
 	}
 	if (bmval1 & FATTR4_WORD1_RAWDEV) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32((u32) MAJOR(stat.rdev));
 		*p++ = cpu_to_be32((u32) MINOR(stat.rdev));
 	}
 	if (bmval1 & FATTR4_WORD1_SPACE_AVAIL) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		dummy64 = (u64)statfs.f_bavail * (u64)statfs.f_bsize;
 		p = xdr_encode_hyper(p, dummy64);
 	}
 	if (bmval1 & FATTR4_WORD1_SPACE_FREE) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		dummy64 = (u64)statfs.f_bfree * (u64)statfs.f_bsize;
 		p = xdr_encode_hyper(p, dummy64);
 	}
 	if (bmval1 & FATTR4_WORD1_SPACE_TOTAL) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		dummy64 = (u64)statfs.f_blocks * (u64)statfs.f_bsize;
 		p = xdr_encode_hyper(p, dummy64);
 	}
 	if (bmval1 & FATTR4_WORD1_SPACE_USED) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			goto out_resource;
 		dummy64 = (u64)stat.blocks << 9;
 		p = xdr_encode_hyper(p, dummy64);
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_ACCESS) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (s64)stat.atime.tv_sec);
 		*p++ = cpu_to_be32(stat.atime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
 			goto out_resource;
 		p = encode_time_delta(p, d_inode(dentry));
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_METADATA) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (s64)stat.ctime.tv_sec);
 		*p++ = cpu_to_be32(stat.ctime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_MODIFY) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
 			goto out_resource;
 		p = xdr_encode_hyper(p, (s64)stat.mtime.tv_sec);
 		*p++ = cpu_to_be32(stat.mtime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
 		struct kstat parent_stat;
 		u64 ino = stat.ino;

 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
                 	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) {
 			err = get_parent_attributes(exp, &parent_stat);
 			if (err)
 				goto out_nfserr;
 			ino = parent_stat.ino;
 		}
 		p = xdr_encode_hyper(p, ino);
 	}
 #ifdef CONFIG_NFSD_PNFS
 	if (bmval1 & FATTR4_WORD1_FS_LAYOUT_TYPES) {
 		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
 		if (status)
 			goto out;
 	}

 	if (bmval2 & FATTR4_WORD2_LAYOUT_TYPES) {
 		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
 		if (status)
 			goto out;
 	}

 	if (bmval2 & FATTR4_WORD2_LAYOUT_BLKSIZE) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		*p++ = cpu_to_be32(stat.blksize);
 	}
 #endif /* CONFIG_NFSD_PNFS */
 	if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
 		u32 supp[3];

 		memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));
 		supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
 		supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
 		supp[2] &= NFSD_SUPPATTR_EXCLCREAT_WORD2;

 		status = nfsd4_encode_bitmap(xdr, supp[0], supp[1], supp[2]);
 		if (status)
 			goto out;
 	}

 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
 		status = nfsd4_encode_security_label(xdr, rqstp, context,
 								contextlen);
 		if (status)
 			goto out;
 	}
 #endif

 	if (bmval2 & FATTR4_WORD2_XATTR_SUPPORT) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
 		err = xattr_supported_namespace(d_inode(dentry),
 						XATTR_USER_PREFIX);
 		*p++ = cpu_to_be32(err == 0);
 	}

 	attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
 	write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
 	status = nfs_ok;

 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (context)
 		security_release_secctx(context, contextlen);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
 		fh_put(tempfh);
 		kfree(tempfh);
 	}
 	if (status)
 		xdr_truncate_encode(xdr, starting_len);
 	return status;
 out_nfserr:
 	status = nfserrno(err);
 	goto out;
 out_resource:
 	status = nfserr_resource;
 	goto out;
 }

 static void svcxdr_init_encode_from_buffer(struct xdr_stream *xdr,
 				struct xdr_buf *buf, __be32 *p, int bytes)
 {
 	xdr->scratch.iov_len = 0;
 	memset(buf, 0, sizeof(struct xdr_buf));
 	buf->head[0].iov_base = p;
 	buf->head[0].iov_len = 0;
 	buf->len = 0;
 	xdr->buf = buf;
 	xdr->iov = buf->head;
 	xdr->p = p;
 	xdr->end = (void *)p + bytes;
 	buf->buflen = bytes;
 }

 __be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
 			struct svc_fh *fhp, struct svc_export *exp,
 			struct dentry *dentry, u32 *bmval,
 			struct svc_rqst *rqstp, int ignore_crossmnt)
 {
 	struct xdr_buf dummy;
 	struct xdr_stream xdr;
 	__be32 ret;

 	svcxdr_init_encode_from_buffer(&xdr, &dummy, *p, words << 2);
 	ret = nfsd4_encode_fattr(&xdr, fhp, exp, dentry, bmval, rqstp,
 							ignore_crossmnt);
 	*p = xdr.p;
 	return ret;
 }

 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 xdr_stream *xdr, struct nfsd4_readdir *cd,
 			const char *name, int namlen)
 {
 	struct svc_export *exp = cd->rd_fhp->fh_export;
 	struct dentry *dentry;
 	__be32 nfserr;
 	int ignore_crossmnt = 0;

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

 	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(xdr, NULL, exp, dentry, cd->rd_bmval,
 					cd->rd_rqstp, ignore_crossmnt);
 out_put:
 	dput(dentry);
 	exp_put(exp);
 	return nfserr;
 }

 static __be32 *
 nfsd4_encode_rdattr_error(struct xdr_stream *xdr, __be32 nfserr)
 {
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return NULL;
 	*p++ = htonl(2);
 	*p++ = htonl(FATTR4_WORD0_RDATTR_ERROR); /* bmval0 */
 	*p++ = htonl(0);			 /* bmval1 */

 	*p++ = htonl(4);     /* attribute length */
 	*p++ = nfserr;       /* no htonl */
 	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);
 	struct xdr_stream *xdr = cd->xdr;
 	int start_offset = xdr->buf->len;
 	int cookie_offset;
 	u32 name_and_cookie;
 	int entry_bytes;
 	__be32 nfserr = nfserr_toosmall;
 	__be64 wire_offset;
 	__be32 *p;

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

 	if (cd->cookie_offset) {
 		wire_offset = cpu_to_be64(offset);
 		write_bytes_to_xdr_buf(xdr->buf, cd->cookie_offset,
 							&wire_offset, 8);
 	}

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		goto fail;
 	*p++ = xdr_one;                             /* mark entry present */
 	cookie_offset = xdr->buf->len;
 	p = xdr_reserve_space(xdr, 3*4 + namlen);
 	if (!p)
 		goto fail;
 	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(xdr, cd, name, namlen);
 	switch (nfserr) {
 	case nfs_ok:
 		break;
 	case nfserr_resource:
 		nfserr = nfserr_toosmall;
 		goto fail;
 	case nfserr_noent:
 		xdr_truncate_encode(xdr, start_offset);
 		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(xdr, nfserr);
 		if (p == NULL) {
 			nfserr = nfserr_toosmall;
 			goto fail;
 		}
 	}
 	nfserr = nfserr_toosmall;
 	entry_bytes = xdr->buf->len - start_offset;
 	if (entry_bytes > cd->rd_maxcount)
 		goto fail;
 	cd->rd_maxcount -= entry_bytes;
 	/*
 	 * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and
 	 * notes that it could be zero. If it is zero, then the server
 	 * should enforce only the rd_maxcount value.
 	 */
 	if (cd->rd_dircount) {
 		name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8;
 		if (name_and_cookie > cd->rd_dircount && cd->cookie_offset)
 			goto fail;
 		cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie);
 		if (!cd->rd_dircount)
 			cd->rd_maxcount = 0;
 	}

 	cd->cookie_offset = cookie_offset;
 skip_entry:
 	cd->common.err = nfs_ok;
 	return 0;
 fail:
 	xdr_truncate_encode(xdr, start_offset);
 	cd->common.err = nfserr;
 	return -EINVAL;
 }

 static __be32
 nfsd4_encode_stateid(struct xdr_stream *xdr, stateid_t *sid)
 {
 	__be32 *p;

 	p = xdr_reserve_space(xdr, sizeof(stateid_t));
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(sid->si_generation);
 	p = xdr_encode_opaque_fixed(p, &sid->si_opaque,
 					sizeof(stateid_opaque_t));
 	return 0;
 }

 static __be32
 nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 8);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(access->ac_supported);
 	*p++ = cpu_to_be32(access->ac_resp_access);
 	return 0;
 }

 static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 8);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_opaque_fixed(p, bcts->sessionid.data,
 					NFS4_MAX_SESSIONID_LEN);
 	*p++ = cpu_to_be32(bcts->dir);
 	/* Upshifting from TCP to RDMA is not supported */
 	*p++ = cpu_to_be32(0);
 	return 0;
 }

 static __be32
 nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_close *close)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_encode_stateid(xdr, &close->cl_stateid);
 }


 static __be32
 nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_commit *commit)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_opaque_fixed(p, commit->co_verf.data,
 						NFS4_VERIFIER_SIZE);
 	return 0;
 }

 static __be32
 nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_create *create)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return nfserr_resource;
 	encode_cinfo(p, &create->cr_cinfo);
 	return nfsd4_encode_bitmap(xdr, create->cr_bmval[0],
 			create->cr_bmval[1], create->cr_bmval[2]);
 }

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

 	return nfsd4_encode_fattr(xdr, fhp, fhp->fh_export, fhp->fh_dentry,
 				    getattr->ga_bmval, resp->rqstp, 0);
 }

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

 	len = fhp->fh_handle.fh_size;
 	p = xdr_reserve_space(xdr, len + 4);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_opaque(p, &fhp->fh_handle.fh_base, len);
 	return 0;
 }

 /*
 * Including all fields other than the name, a LOCK4denied structure requires
 *   8(clientid) + 4(namelen) + 8(offset) + 8(length) + 4(type) = 32 bytes.
 */
 static __be32
 nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
 {
 	struct xdr_netobj *conf = &ld->ld_owner;
 	__be32 *p;

 again:
 	p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));
 	if (!p) {
 		/*
 		 * Don't fail to return the result just because we can't
 		 * return the conflicting open:
 		 */
 		if (conf->len) {
 			kfree(conf->data);
 			conf->len = 0;
 			conf->data = NULL;
 			goto again;
 		}
 		return nfserr_resource;
 	}
 	p = xdr_encode_hyper(p, ld->ld_start);
 	p = xdr_encode_hyper(p, ld->ld_length);
 	*p++ = cpu_to_be32(ld->ld_type);
 	if (conf->len) {
 		p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8);
 		p = xdr_encode_opaque(p, conf->data, conf->len);
 		kfree(conf->data);
 	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */
 		p = xdr_encode_hyper(p, (u64)0); /* clientid */
 		*p++ = cpu_to_be32(0); /* length of owner name */
 	}
 	return nfserr_denied;
 }

 static __be32
 nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lock *lock)
 {
 	struct xdr_stream *xdr = resp->xdr;

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

 	return nfserr;
 }

 static __be32
 nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lockt *lockt)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	if (nfserr == nfserr_denied)
 		nfsd4_encode_lock_denied(xdr, &lockt->lt_denied);
 	return nfserr;
 }

 static __be32
 nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_locku *locku)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_encode_stateid(xdr, &locku->lu_stateid);
 }


 static __be32
 nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_link *link)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return nfserr_resource;
 	p = encode_cinfo(p, &link->li_cinfo);
 	return 0;
 }


 static __be32
 nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open *open)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	nfserr = nfsd4_encode_stateid(xdr, &open->op_stateid);
 	if (nfserr)
 		return nfserr;
 	p = xdr_reserve_space(xdr, 24);
 	if (!p)
 		return nfserr_resource;
 	p = encode_cinfo(p, &open->op_cinfo);
 	*p++ = cpu_to_be32(open->op_rflags);

 	nfserr = nfsd4_encode_bitmap(xdr, open->op_bmval[0], open->op_bmval[1],
 					open->op_bmval[2]);
 	if (nfserr)
 		return nfserr;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;

 	*p++ = cpu_to_be32(open->op_delegate_type);
 	switch (open->op_delegate_type) {
 	case NFS4_OPEN_DELEGATE_NONE:
 		break;
 	case NFS4_OPEN_DELEGATE_READ:
 		nfserr = nfsd4_encode_stateid(xdr, &open->op_delegate_stateid);
 		if (nfserr)
 			return nfserr;
 		p = xdr_reserve_space(xdr, 20);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(open->op_recall);

 		/*
 		 * TODO: ACE's in delegations
 		 */
 		*p++ = cpu_to_be32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);   /* XXX: is NULL principal ok? */
 		break;
 	case NFS4_OPEN_DELEGATE_WRITE:
 		nfserr = nfsd4_encode_stateid(xdr, &open->op_delegate_stateid);
 		if (nfserr)
 			return nfserr;
 		p = xdr_reserve_space(xdr, 32);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(0);

 		/*
 		 * TODO: space_limit's in delegations
 		 */
 		*p++ = cpu_to_be32(NFS4_LIMIT_SIZE);
 		*p++ = cpu_to_be32(~(u32)0);
 		*p++ = cpu_to_be32(~(u32)0);

 		/*
 		 * TODO: ACE's in delegations
 		 */
 		*p++ = cpu_to_be32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);   /* XXX: is NULL principal ok? */
 		break;
 	case NFS4_OPEN_DELEGATE_NONE_EXT: /* 4.1 */
 		switch (open->op_why_no_deleg) {
 		case WND4_CONTENTION:
 		case WND4_RESOURCE:
 			p = xdr_reserve_space(xdr, 8);
 			if (!p)
 				return nfserr_resource;
 			*p++ = cpu_to_be32(open->op_why_no_deleg);
 			/* deleg signaling not supported yet: */
 			*p++ = cpu_to_be32(0);
 			break;
 		default:
 			p = xdr_reserve_space(xdr, 4);
 			if (!p)
 				return nfserr_resource;
 			*p++ = cpu_to_be32(open->op_why_no_deleg);
 		}
 		break;
 	default:
 		BUG();
 	}
 	/* XXX save filehandle here */
 	return 0;
 }

 static __be32
 nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_confirm *oc)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_encode_stateid(xdr, &oc->oc_resp_stateid);
 }

 static __be32
 nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_downgrade *od)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_encode_stateid(xdr, &od->od_stateid);
 }

 static __be32 nfsd4_encode_splice_read(
 				struct nfsd4_compoundres *resp,
 				struct nfsd4_read *read,
 				struct file *file, unsigned long maxcount)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	struct xdr_buf *buf = xdr->buf;
 	int status, space_left;
 	u32 eof;
 	__be32 nfserr;
 	__be32 *p = xdr->p - 2;

 	/* Make sure there will be room for padding if needed */
 	if (xdr->end - xdr->p < 1)
 		return nfserr_resource;

 	nfserr = nfsd_splice_read(read->rd_rqstp, read->rd_fhp,
 				  file, read->rd_offset, &maxcount, &eof);
 	read->rd_length = maxcount;
 	if (nfserr)
 		goto out_err;
 	status = svc_encode_result_payload(read->rd_rqstp,
 					   buf->head[0].iov_len, maxcount);
 	if (status) {
 		nfserr = nfserrno(status);
 		goto out_err;
 	}

 	*(p++) = htonl(eof);
 	*(p++) = htonl(maxcount);

 	buf->page_len = maxcount;
 	buf->len += maxcount;
 	xdr->page_ptr += (buf->page_base + maxcount + PAGE_SIZE - 1)
 							/ PAGE_SIZE;

 	/* Use rest of head for padding and remaining ops: */
 	buf->tail[0].iov_base = xdr->p;
 	buf->tail[0].iov_len = 0;
 	xdr->iov = buf->tail;
 	if (maxcount&3) {
 		int pad = 4 - (maxcount&3);

 		*(xdr->p++) = 0;

 		buf->tail[0].iov_base += maxcount&3;
 		buf->tail[0].iov_len = pad;
 		buf->len += pad;
 	}

 	space_left = min_t(int, (void *)xdr->end - (void *)xdr->p,
 				buf->buflen - buf->len);
 	buf->buflen = buf->len + space_left;
 	xdr->end = (__be32 *)((void *)xdr->end + space_left);

 	return 0;

 out_err:
 	/*
 	 * nfsd_splice_actor may have already messed with the
 	 * page length; reset it so as not to confuse
 	 * xdr_truncate_encode in our caller.
 	 */
 	buf->page_len = 0;
 	return nfserr;
 }

 static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 				 struct nfsd4_read *read,
 				 struct file *file, unsigned long maxcount)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	u32 eof;
 	int starting_len = xdr->buf->len - 8;
 	__be32 nfserr;
 	__be32 tmp;
 	int pad;

 	read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, maxcount);
 	if (read->rd_vlen < 0)
 		return nfserr_resource;

 	nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
 			    resp->rqstp->rq_vec, read->rd_vlen, &maxcount,
 			    &eof);
 	read->rd_length = maxcount;
 	if (nfserr)
 		return nfserr;
 	if (svc_encode_result_payload(resp->rqstp, starting_len + 8, maxcount))
 		return nfserr_io;
 	xdr_truncate_encode(xdr, starting_len + 8 + xdr_align_size(maxcount));

 	tmp = htonl(eof);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);
 	tmp = htonl(maxcount);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);

 	tmp = xdr_zero;
 	pad = (maxcount&3) ? 4 - (maxcount&3) : 0;
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 8 + maxcount,
 								&tmp, pad);
 	return 0;

 }

 static __be32
 nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 		  struct nfsd4_read *read)
 {
 	unsigned long maxcount;
 	struct xdr_stream *xdr = resp->xdr;
 	struct file *file;
 	int starting_len = xdr->buf->len;
 	__be32 *p;

 	if (nfserr)
 		return nfserr;
 	file = read->rd_nf->nf_file;

 	p = xdr_reserve_space(xdr, 8); /* eof flag and byte count */
 	if (!p) {
 		WARN_ON_ONCE(test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags));
 		return nfserr_resource;
 	}
 	if (resp->xdr->buf->page_len &&
 	    test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags)) {
 		WARN_ON_ONCE(1);
 		return nfserr_serverfault;
 	}
 	xdr_commit_encode(xdr);

 	maxcount = min_t(unsigned long, read->rd_length,
 			 (xdr->buf->buflen - xdr->buf->len));

 	if (file->f_op->splice_read &&
 	    test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags))
 		nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
 	else
 		nfserr = nfsd4_encode_readv(resp, read, file, maxcount);

 	if (nfserr)
 		xdr_truncate_encode(xdr, starting_len);

 	return nfserr;
 }

 static __be32
 nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readlink *readlink)
 {
 	int maxcount;
 	__be32 wire_count;
 	int zero = 0;
 	struct xdr_stream *xdr = resp->xdr;
 	int length_offset = xdr->buf->len;
 	int status;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	maxcount = PAGE_SIZE;

 	p = xdr_reserve_space(xdr, maxcount);
 	if (!p)
 		return nfserr_resource;
 	/*
 	 * XXX: By default, vfs_readlink() will truncate symlinks if they
 	 * would overflow the buffer.  Is this kosher in NFSv4?  If not, one
 	 * easy fix is: if vfs_readlink() precisely fills the buffer, assume
 	 * that truncation occurred, and return NFS4ERR_RESOURCE.
 	 */
 	nfserr = nfsd_readlink(readlink->rl_rqstp, readlink->rl_fhp,
 						(char *)p, &maxcount);
 	if (nfserr == nfserr_isdir)
 		nfserr = nfserr_inval;
 	if (nfserr)
 		goto out_err;
 	status = svc_encode_result_payload(readlink->rl_rqstp, length_offset,
 					   maxcount);
 	if (status) {
 		nfserr = nfserrno(status);
 		goto out_err;
 	}

 	wire_count = htonl(maxcount);
 	write_bytes_to_xdr_buf(xdr->buf, length_offset, &wire_count, 4);
 	xdr_truncate_encode(xdr, length_offset + 4 + ALIGN(maxcount, 4));
 	if (maxcount & 3)
 		write_bytes_to_xdr_buf(xdr->buf, length_offset + 4 + maxcount,
 						&zero, 4 - (maxcount&3));
 	return 0;

 out_err:
 	xdr_truncate_encode(xdr, length_offset);
 	return nfserr;
 }

 static __be32
 nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readdir *readdir)
 {
 	int maxcount;
 	int bytes_left;
 	loff_t offset;
 	__be64 wire_offset;
 	struct xdr_stream *xdr = resp->xdr;
 	int starting_len = xdr->buf->len;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
 	if (!p)
 		return nfserr_resource;

 	/* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
 	*p++ = cpu_to_be32(0);
 	*p++ = cpu_to_be32(0);
 	xdr->buf->head[0].iov_len = (char *)xdr->p -
 				    (char *)xdr->buf->head[0].iov_base;

 	/*
 	 * Number of bytes left for directory entries allowing for the
 	 * final 8 bytes of the readdir and a following failed op:
 	 */
 	bytes_left = xdr->buf->buflen - xdr->buf->len
 			- COMPOUND_ERR_SLACK_SPACE - 8;
 	if (bytes_left < 0) {
 		nfserr = nfserr_resource;
 		goto err_no_verf;
 	}
 	maxcount = svc_max_payload(resp->rqstp);
 	maxcount = min_t(u32, readdir->rd_maxcount, maxcount);
 	/*
 	 * Note the rfc defines rd_maxcount as the size of the
 	 * READDIR4resok structure, which includes the verifier above
 	 * and the 8 bytes encoded at the end of this function:
 	 */
 	if (maxcount < 16) {
 		nfserr = nfserr_toosmall;
 		goto err_no_verf;
 	}
 	maxcount = min_t(int, maxcount-16, bytes_left);

 	/* RFC 3530 14.2.24 allows us to ignore dircount when it's 0: */
 	if (!readdir->rd_dircount)
 		readdir->rd_dircount = svc_max_payload(resp->rqstp);

 	readdir->xdr = xdr;
 	readdir->rd_maxcount = maxcount;
 	readdir->common.err = 0;
 	readdir->cookie_offset = 0;

 	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 &&
 	    xdr->buf->len == starting_len + 8) {
 		/* nothing encoded; which limit did we hit?: */
 		if (maxcount - 16 < bytes_left)
 			/* It was the fault of rd_maxcount: */
 			nfserr = nfserr_toosmall;
 		else
 			/* We ran out of buffer space: */
 			nfserr = nfserr_resource;
 	}
 	if (nfserr)
 		goto err_no_verf;

 	if (readdir->cookie_offset) {
 		wire_offset = cpu_to_be64(offset);
 		write_bytes_to_xdr_buf(xdr->buf, readdir->cookie_offset,
 							&wire_offset, 8);
 	}

 	p = xdr_reserve_space(xdr, 8);
 	if (!p) {
 		WARN_ON_ONCE(1);
 		goto err_no_verf;
 	}
 	*p++ = 0;	/* no more entries */
 	*p++ = htonl(readdir->common.err == nfserr_eof);

 	return 0;
 err_no_verf:
 	xdr_truncate_encode(xdr, starting_len);
 	return nfserr;
 }

 static __be32
 nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_remove *remove)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return nfserr_resource;
 	p = encode_cinfo(p, &remove->rm_cinfo);
 	return 0;
 }

 static __be32
 nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_rename *rename)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 40);
 	if (!p)
 		return nfserr_resource;
 	p = encode_cinfo(p, &rename->rn_sinfo);
 	p = encode_cinfo(p, &rename->rn_tinfo);
 	return 0;
 }

 static __be32
 nfsd4_do_encode_secinfo(struct xdr_stream *xdr, struct svc_export *exp)
 {
 	u32 i, nflavs, supported;
 	struct exp_flavor_info *flavs;
 	struct exp_flavor_info def_flavs[2];
 	__be32 *p, *flavorsp;
 	static bool report = true;

 	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;
 		}
 	}

 	supported = 0;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	flavorsp = p++;		/* to be backfilled later */

 	for (i = 0; i < nflavs; i++) {
 		rpc_authflavor_t pf = flavs[i].pseudoflavor;
 		struct rpcsec_gss_info info;

 		if (rpcauth_get_gssinfo(pf, &info) == 0) {
 			supported++;
 			p = xdr_reserve_space(xdr, 4 + 4 +
 					      XDR_LEN(info.oid.len) + 4 + 4);
 			if (!p)
 				return nfserr_resource;
 			*p++ = cpu_to_be32(RPC_AUTH_GSS);
 			p = xdr_encode_opaque(p,  info.oid.data, info.oid.len);
 			*p++ = cpu_to_be32(info.qop);
 			*p++ = cpu_to_be32(info.service);
 		} else if (pf < RPC_AUTH_MAXFLAVOR) {
 			supported++;
 			p = xdr_reserve_space(xdr, 4);
 			if (!p)
 				return nfserr_resource;
 			*p++ = cpu_to_be32(pf);
 		} else {
 			if (report)
 				pr_warn("NFS: SECINFO: security flavor %u "
 					"is not supported\n", pf);
 		}
 	}

 	if (nflavs != supported)
 		report = false;
 	*flavorsp = htonl(supported);
 	return 0;
 }

 static __be32
 nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
 		     struct nfsd4_secinfo *secinfo)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_do_encode_secinfo(xdr, secinfo->si_exp);
 }

 static __be32
 nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
 		     struct nfsd4_secinfo_no_name *secinfo)
 {
 	struct xdr_stream *xdr = resp->xdr;

 	return nfsd4_do_encode_secinfo(xdr, 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)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 16);
 	if (!p)
 		return nfserr_resource;
 	if (nfserr) {
 		*p++ = cpu_to_be32(3);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);
 	}
 	else {
 		*p++ = cpu_to_be32(3);
 		*p++ = cpu_to_be32(setattr->sa_bmval[0]);
 		*p++ = cpu_to_be32(setattr->sa_bmval[1]);
 		*p++ = cpu_to_be32(setattr->sa_bmval[2]);
 	}
 	return nfserr;
 }

 static __be32
 nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	if (!nfserr) {
 		p = xdr_reserve_space(xdr, 8 + NFS4_VERIFIER_SIZE);
 		if (!p)
 			return nfserr_resource;
 		p = xdr_encode_opaque_fixed(p, &scd->se_clientid, 8);
 		p = xdr_encode_opaque_fixed(p, &scd->se_confirm,
 						NFS4_VERIFIER_SIZE);
 	}
 	else if (nfserr == nfserr_clid_inuse) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(0);
 		*p++ = cpu_to_be32(0);
 	}
 	return nfserr;
 }

 static __be32
 nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_write *write)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 16);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(write->wr_bytes_written);
 	*p++ = cpu_to_be32(write->wr_how_written);
 	p = xdr_encode_opaque_fixed(p, write->wr_verifier.data,
 						NFS4_VERIFIER_SIZE);
 	return 0;
 }

 static __be32
 nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_exchange_id *exid)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 	char *major_id;
 	char *server_scope;
 	int major_id_sz;
 	int server_scope_sz;
 	uint64_t minor_id = 0;
 	struct nfsd_net *nn = net_generic(SVC_NET(resp->rqstp), nfsd_net_id);

 	major_id = nn->nfsd_name;
 	major_id_sz = strlen(nn->nfsd_name);
 	server_scope = nn->nfsd_name;
 	server_scope_sz = strlen(nn->nfsd_name);

 	p = xdr_reserve_space(xdr,
 		8 /* eir_clientid */ +
 		4 /* eir_sequenceid */ +
 		4 /* eir_flags */ +
 		4 /* spr_how */);
 	if (!p)
 		return nfserr_resource;

 	p = xdr_encode_opaque_fixed(p, &exid->clientid, 8);
 	*p++ = cpu_to_be32(exid->seqid);
 	*p++ = cpu_to_be32(exid->flags);

 	*p++ = cpu_to_be32(exid->spa_how);

 	switch (exid->spa_how) {
 	case SP4_NONE:
 		break;
 	case SP4_MACH_CRED:
 		/* spo_must_enforce bitmap: */
 		nfserr = nfsd4_encode_bitmap(xdr,
 					exid->spo_must_enforce[0],
 					exid->spo_must_enforce[1],
 					exid->spo_must_enforce[2]);
 		if (nfserr)
 			return nfserr;
 		/* spo_must_allow bitmap: */
 		nfserr = nfsd4_encode_bitmap(xdr,
 					exid->spo_must_allow[0],
 					exid->spo_must_allow[1],
 					exid->spo_must_allow[2]);
 		if (nfserr)
 			return nfserr;
 		break;
 	default:
 		WARN_ON_ONCE(1);
 	}

 	p = xdr_reserve_space(xdr,
 		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) */);
 	if (!p)
 		return nfserr_resource;

 	/* The server_owner struct */
 	p = xdr_encode_hyper(p, minor_id);      /* Minor id */
 	/* major id */
 	p = xdr_encode_opaque(p, major_id, major_id_sz);

 	/* Server scope */
 	p = xdr_encode_opaque(p, server_scope, server_scope_sz);

 	/* Implementation id */
 	*p++ = cpu_to_be32(0);	/* zero length nfs_impl_id4 array */
 	return 0;
 }

 static __be32
 nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
 			    struct nfsd4_create_session *sess)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 24);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_opaque_fixed(p, sess->sessionid.data,
 					NFS4_MAX_SESSIONID_LEN);
 	*p++ = cpu_to_be32(sess->seqid);
 	*p++ = cpu_to_be32(sess->flags);

 	p = xdr_reserve_space(xdr, 28);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(0); /* headerpadsz */
 	*p++ = cpu_to_be32(sess->fore_channel.maxreq_sz);
 	*p++ = cpu_to_be32(sess->fore_channel.maxresp_sz);
 	*p++ = cpu_to_be32(sess->fore_channel.maxresp_cached);
 	*p++ = cpu_to_be32(sess->fore_channel.maxops);
 	*p++ = cpu_to_be32(sess->fore_channel.maxreqs);
 	*p++ = cpu_to_be32(sess->fore_channel.nr_rdma_attrs);

 	if (sess->fore_channel.nr_rdma_attrs) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(sess->fore_channel.rdma_attrs);
 	}

 	p = xdr_reserve_space(xdr, 28);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(0); /* headerpadsz */
 	*p++ = cpu_to_be32(sess->back_channel.maxreq_sz);
 	*p++ = cpu_to_be32(sess->back_channel.maxresp_sz);
 	*p++ = cpu_to_be32(sess->back_channel.maxresp_cached);
 	*p++ = cpu_to_be32(sess->back_channel.maxops);
 	*p++ = cpu_to_be32(sess->back_channel.maxreqs);
 	*p++ = cpu_to_be32(sess->back_channel.nr_rdma_attrs);

 	if (sess->back_channel.nr_rdma_attrs) {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(sess->back_channel.rdma_attrs);
 	}
 	return 0;
 }

 static __be32
 nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_sequence *seq)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 20);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_opaque_fixed(p, seq->sessionid.data,
 					NFS4_MAX_SESSIONID_LEN);
 	*p++ = cpu_to_be32(seq->seqid);
 	*p++ = cpu_to_be32(seq->slotid);
 	/* Note slotid's are numbered from zero: */
 	*p++ = cpu_to_be32(seq->maxslots - 1); /* sr_highest_slotid */
 	*p++ = cpu_to_be32(seq->maxslots - 1); /* sr_target_highest_slotid */
 	*p++ = cpu_to_be32(seq->status_flags);

 	resp->cstate.data_offset = xdr->buf->len; /* DRC cache data pointer */
 	return 0;
 }

 static __be32
 nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
 			  struct nfsd4_test_stateid *test_stateid)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	struct nfsd4_test_stateid_id *stateid, *next;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4 + (4 * test_stateid->ts_num_ids));
 	if (!p)
 		return nfserr_resource;
 	*p++ = htonl(test_stateid->ts_num_ids);

 	list_for_each_entry_safe(stateid, next, &test_stateid->ts_stateid_list, ts_id_list) {
 		*p++ = stateid->ts_id_status;
 	}

 	return 0;
 }

 #ifdef CONFIG_NFSD_PNFS
 static __be32
 nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_getdeviceinfo *gdev)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	const struct nfsd4_layout_ops *ops;
 	u32 starting_len = xdr->buf->len, needed_len;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;

 	*p++ = cpu_to_be32(gdev->gd_layout_type);

 	/* If maxcount is 0 then just update notifications */
 	if (gdev->gd_maxcount != 0) {
 		ops = nfsd4_layout_ops[gdev->gd_layout_type];
 		nfserr = ops->encode_getdeviceinfo(xdr, gdev);
 		if (nfserr) {
 			/*
 			 * We don't bother to burden the layout drivers with
 			 * enforcing gd_maxcount, just tell the client to
 			 * come back with a bigger buffer if it's not enough.
 			 */
 			if (xdr->buf->len + 4 > gdev->gd_maxcount)
 				goto toosmall;
 			return nfserr;
 		}
 	}

 	if (gdev->gd_notify_types) {
 		p = xdr_reserve_space(xdr, 4 + 4);
 		if (!p)
 			return nfserr_resource;
 		*p++ = cpu_to_be32(1);			/* bitmap length */
 		*p++ = cpu_to_be32(gdev->gd_notify_types);
 	} else {
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			return nfserr_resource;
 		*p++ = 0;
 	}

 	return 0;
 toosmall:
 	dprintk("%s: maxcount too small\n", __func__);
 	needed_len = xdr->buf->len + 4 /* notifications */;
 	xdr_truncate_encode(xdr, starting_len);
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(needed_len);
 	return nfserr_toosmall;
 }

 static __be32
 nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_layoutget *lgp)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	const struct nfsd4_layout_ops *ops;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 36 + sizeof(stateid_opaque_t));
 	if (!p)
 		return nfserr_resource;

 	*p++ = cpu_to_be32(1);	/* we always set return-on-close */
 	*p++ = cpu_to_be32(lgp->lg_sid.si_generation);
 	p = xdr_encode_opaque_fixed(p, &lgp->lg_sid.si_opaque,
 				    sizeof(stateid_opaque_t));

 	*p++ = cpu_to_be32(1);	/* we always return a single layout */
 	p = xdr_encode_hyper(p, lgp->lg_seg.offset);
 	p = xdr_encode_hyper(p, lgp->lg_seg.length);
 	*p++ = cpu_to_be32(lgp->lg_seg.iomode);
 	*p++ = cpu_to_be32(lgp->lg_layout_type);

 	ops = nfsd4_layout_ops[lgp->lg_layout_type];
 	return ops->encode_layoutget(xdr, lgp);
 }

 static __be32
 nfsd4_encode_layoutcommit(struct nfsd4_compoundres *resp, __be32 nfserr,
 			  struct nfsd4_layoutcommit *lcp)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(lcp->lc_size_chg);
 	if (lcp->lc_size_chg) {
 		p = xdr_reserve_space(xdr, 8);
 		if (!p)
 			return nfserr_resource;
 		p = xdr_encode_hyper(p, lcp->lc_newsize);
 	}

 	return 0;
 }

 static __be32
 nfsd4_encode_layoutreturn(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_layoutreturn *lrp)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;
 	*p++ = cpu_to_be32(lrp->lrs_present);
 	if (lrp->lrs_present)
 		return nfsd4_encode_stateid(xdr, &lrp->lr_sid);
 	return 0;
 }
 #endif /* CONFIG_NFSD_PNFS */

 static __be32
 nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
 		struct nfsd42_write_res *write, bool sync)
 {
 	__be32 *p;
 	p = xdr_reserve_space(resp->xdr, 4);
 	if (!p)
 		return nfserr_resource;

 	if (sync)
 		*p++ = cpu_to_be32(0);
 	else {
 		__be32 nfserr;
 		*p++ = cpu_to_be32(1);
 		nfserr = nfsd4_encode_stateid(resp->xdr, &write->cb_stateid);
 		if (nfserr)
 			return nfserr;
 	}
 	p = xdr_reserve_space(resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
 	if (!p)
 		return nfserr_resource;

 	p = xdr_encode_hyper(p, write->wr_bytes_written);
 	*p++ = cpu_to_be32(write->wr_stable_how);
 	p = xdr_encode_opaque_fixed(p, write->wr_verifier.data,
 				    NFS4_VERIFIER_SIZE);
 	return nfs_ok;
 }

 static __be32
 nfsd42_encode_nl4_server(struct nfsd4_compoundres *resp, struct nl4_server *ns)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	struct nfs42_netaddr *addr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 4);
 	*p++ = cpu_to_be32(ns->nl4_type);

 	switch (ns->nl4_type) {
 	case NL4_NETADDR:
 		addr = &ns->u.nl4_addr;

 		/* netid_len, netid, uaddr_len, uaddr (port included
 		 * in RPCBIND_MAXUADDRLEN)
 		 */
 		p = xdr_reserve_space(xdr,
 			4 /* netid len */ +
 			(XDR_QUADLEN(addr->netid_len) * 4) +
 			4 /* uaddr len */ +
 			(XDR_QUADLEN(addr->addr_len) * 4));
 		if (!p)
 			return nfserr_resource;

 		*p++ = cpu_to_be32(addr->netid_len);
 		p = xdr_encode_opaque_fixed(p, addr->netid,
 					    addr->netid_len);
 		*p++ = cpu_to_be32(addr->addr_len);
 		p = xdr_encode_opaque_fixed(p, addr->addr,
 					addr->addr_len);
 		break;
 	default:
 		WARN_ON_ONCE(ns->nl4_type != NL4_NETADDR);
 		return nfserr_inval;
 	}

 	return 0;
 }

 static __be32
 nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
 		  struct nfsd4_copy *copy)
 {
 	__be32 *p;

 	nfserr = nfsd42_encode_write_res(resp, &copy->cp_res,
 					 !!copy->cp_synchronous);
 	if (nfserr)
 		return nfserr;

 	p = xdr_reserve_space(resp->xdr, 4 + 4);
 	*p++ = xdr_one; /* cr_consecutive */
 	*p++ = cpu_to_be32(copy->cp_synchronous);
 	return 0;
 }

 static __be32
 nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
 			    struct nfsd4_offload_status *os)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 8 + 4);
 	if (!p)
 		return nfserr_resource;
 	p = xdr_encode_hyper(p, os->count);
 	*p++ = cpu_to_be32(0);
 	return nfserr;
 }

 static __be32
 nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
 			    struct nfsd4_read *read,
 			    unsigned long *maxcount, u32 *eof,
 			    loff_t *pos)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	struct file *file = read->rd_nf->nf_file;
 	int starting_len = xdr->buf->len;
 	loff_t hole_pos;
 	__be32 nfserr;
 	__be32 *p, tmp;
 	__be64 tmp64;

 	hole_pos = pos ? *pos : vfs_llseek(file, read->rd_offset, SEEK_HOLE);
 	if (hole_pos > read->rd_offset)
 		*maxcount = min_t(unsigned long, *maxcount, hole_pos - read->rd_offset);
 	*maxcount = min_t(unsigned long, *maxcount, (xdr->buf->buflen - xdr->buf->len));

 	/* Content type, offset, byte count */
 	p = xdr_reserve_space(xdr, 4 + 8 + 4);
 	if (!p)
 		return nfserr_resource;

 	read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, *maxcount);
 	if (read->rd_vlen < 0)
 		return nfserr_resource;

 	nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
 			    resp->rqstp->rq_vec, read->rd_vlen, maxcount, eof);
 	if (nfserr)
 		return nfserr;
 	xdr_truncate_encode(xdr, starting_len + 16 + xdr_align_size(*maxcount));

 	tmp = htonl(NFS4_CONTENT_DATA);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len,      &tmp,   4);
 	tmp64 = cpu_to_be64(read->rd_offset);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 4,  &tmp64, 8);
 	tmp = htonl(*maxcount);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 12, &tmp,   4);

 	tmp = xdr_zero;
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 16 + *maxcount, &tmp,
 			       xdr_pad_size(*maxcount));
 	return nfs_ok;
 }

 static __be32
 nfsd4_encode_read_plus_hole(struct nfsd4_compoundres *resp,
 			    struct nfsd4_read *read,
 			    unsigned long *maxcount, u32 *eof)
 {
 	struct file *file = read->rd_nf->nf_file;
 	loff_t data_pos = vfs_llseek(file, read->rd_offset, SEEK_DATA);
 	loff_t f_size = i_size_read(file_inode(file));
 	unsigned long count;
 	__be32 *p;

 	if (data_pos == -ENXIO)
 		data_pos = f_size;
 	else if (data_pos <= read->rd_offset || (data_pos < f_size && data_pos % PAGE_SIZE))
 		return nfsd4_encode_read_plus_data(resp, read, maxcount, eof, &f_size);
 	count = data_pos - read->rd_offset;

 	/* Content type, offset, byte count */
 	p = xdr_reserve_space(resp->xdr, 4 + 8 + 8);
 	if (!p)
 		return nfserr_resource;

 	*p++ = htonl(NFS4_CONTENT_HOLE);
 	 p   = xdr_encode_hyper(p, read->rd_offset);
 	 p   = xdr_encode_hyper(p, count);

 	*eof = (read->rd_offset + count) >= f_size;
 	*maxcount = min_t(unsigned long, count, *maxcount);
 	return nfs_ok;
 }

 static __be32
 nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
 		       struct nfsd4_read *read)
 {
 	unsigned long maxcount, count;
 	struct xdr_stream *xdr = resp->xdr;
 	struct file *file;
 	int starting_len = xdr->buf->len;
 	int last_segment = xdr->buf->len;
 	int segments = 0;
 	__be32 *p, tmp;
 	bool is_data;
 	loff_t pos;
 	u32 eof;

 	if (nfserr)
 		return nfserr;
 	file = read->rd_nf->nf_file;

 	/* eof flag, segment count */
 	p = xdr_reserve_space(xdr, 4 + 4);
 	if (!p)
 		return nfserr_resource;
 	xdr_commit_encode(xdr);

 	maxcount = min_t(unsigned long, read->rd_length,
 			 (xdr->buf->buflen - xdr->buf->len));
 	count    = maxcount;

 	eof = read->rd_offset >= i_size_read(file_inode(file));
 	if (eof)
 		goto out;

 	pos = vfs_llseek(file, read->rd_offset, SEEK_HOLE);
 	is_data = pos > read->rd_offset;

 	while (count > 0 && !eof) {
 		maxcount = count;
 		if (is_data)
 			nfserr = nfsd4_encode_read_plus_data(resp, read, &maxcount, &eof,
 						segments == 0 ? &pos : NULL);
 		else
 			nfserr = nfsd4_encode_read_plus_hole(resp, read, &maxcount, &eof);
 		if (nfserr)
 			goto out;
 		count -= maxcount;
 		read->rd_offset += maxcount;
 		is_data = !is_data;
 		last_segment = xdr->buf->len;
 		segments++;
 	}

 out:
 	if (nfserr && segments == 0)
 		xdr_truncate_encode(xdr, starting_len);
 	else {
 		if (nfserr) {
 			xdr_truncate_encode(xdr, last_segment);
 			nfserr = nfs_ok;
 			eof = 0;
 		}
 		tmp = htonl(eof);
 		write_bytes_to_xdr_buf(xdr->buf, starting_len,     &tmp, 4);
 		tmp = htonl(segments);
 		write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
 	}

 	return nfserr;
 }

 static __be32
 nfsd4_encode_copy_notify(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_copy_notify *cn)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	if (nfserr)
 		return nfserr;

 	/* 8 sec, 4 nsec */
 	p = xdr_reserve_space(xdr, 12);
 	if (!p)
 		return nfserr_resource;

 	/* cnr_lease_time */
 	p = xdr_encode_hyper(p, cn->cpn_sec);
 	*p++ = cpu_to_be32(cn->cpn_nsec);

 	/* cnr_stateid */
 	nfserr = nfsd4_encode_stateid(xdr, &cn->cpn_cnr_stateid);
 	if (nfserr)
 		return nfserr;

 	/* cnr_src.nl_nsvr */
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;

 	*p++ = cpu_to_be32(1);

 	return nfsd42_encode_nl4_server(resp, &cn->cpn_src);
 }

 static __be32
 nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
 		  struct nfsd4_seek *seek)
 {
 	__be32 *p;

 	p = xdr_reserve_space(resp->xdr, 4 + 8);
 	*p++ = cpu_to_be32(seek->seek_eof);
 	p = xdr_encode_hyper(p, seek->seek_pos);

 	return 0;
 }

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

 /*
  * Encode kmalloc-ed buffer in to XDR stream.
  */
 static __be32
 nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
 {
 	u32 cplen;
 	__be32 *p;

 	cplen = min_t(unsigned long, buflen,
 		      ((void *)xdr->end - (void *)xdr->p));
 	p = xdr_reserve_space(xdr, cplen);
 	if (!p)
 		return nfserr_resource;

 	memcpy(p, buf, cplen);
 	buf += cplen;
 	buflen -= cplen;

 	while (buflen) {
 		cplen = min_t(u32, buflen, PAGE_SIZE);
 		p = xdr_reserve_space(xdr, cplen);
 		if (!p)
 			return nfserr_resource;

 		memcpy(p, buf, cplen);

 		if (cplen < PAGE_SIZE) {
 			/*
 			 * We're done, with a length that wasn't page
 			 * aligned, so possibly not word aligned. Pad
 			 * any trailing bytes with 0.
 			 */
 			xdr_encode_opaque_fixed(p, NULL, cplen);
 			break;
 		}

 		buflen -= PAGE_SIZE;
 		buf += PAGE_SIZE;
 	}

 	return 0;
 }

 static __be32
 nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_getxattr *getxattr)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p, err;

 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
 		return nfserr_resource;

 	*p = cpu_to_be32(getxattr->getxa_len);

 	if (getxattr->getxa_len == 0)
 		return 0;

 	err = nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
 				    getxattr->getxa_len);

 	kvfree(getxattr->getxa_buf);

 	return err;
 }

 static __be32
 nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_setxattr *setxattr)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return nfserr_resource;

 	encode_cinfo(p, &setxattr->setxa_cinfo);

 	return 0;
 }

 /*
  * See if there are cookie values that can be rejected outright.
  */
 static __be32
 nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
 				u32 *offsetp)
 {
 	u64 cookie = listxattrs->lsxa_cookie;

 	/*
 	 * If the cookie is larger than the maximum number we can fit
 	 * in either the buffer we just got back from vfs_listxattr, or,
 	 * XDR-encoded, in the return buffer, it's invalid.
 	 */
 	if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
 		return nfserr_badcookie;

 	if (cookie > (listxattrs->lsxa_maxcount /
 		      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
 		return nfserr_badcookie;

 	*offsetp = (u32)cookie;
 	return 0;
 }

 static __be32
 nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
 			struct nfsd4_listxattrs *listxattrs)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	u32 cookie_offset, count_offset, eof;
 	u32 left, xdrleft, slen, count;
 	u32 xdrlen, offset;
 	u64 cookie;
 	char *sp;
 	__be32 status, tmp;
 	__be32 *p;
 	u32 nuser;

 	eof = 1;

 	status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
 	if (status)
 		goto out;

 	/*
 	 * Reserve space for the cookie and the name array count. Record
 	 * the offsets to save them later.
 	 */
 	cookie_offset = xdr->buf->len;
 	count_offset = cookie_offset + 8;
 	p = xdr_reserve_space(xdr, 12);
 	if (!p) {
 		status = nfserr_resource;
 		goto out;
 	}

 	count = 0;
 	left = listxattrs->lsxa_len;
 	sp = listxattrs->lsxa_buf;
 	nuser = 0;

 	xdrleft = listxattrs->lsxa_maxcount;

 	while (left > 0 && xdrleft > 0) {
 		slen = strlen(sp);

 		/*
 		 * Check if this is a "user." attribute, skip it if not.
 		 */
 		if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
 			goto contloop;

 		slen -= XATTR_USER_PREFIX_LEN;
 		xdrlen = 4 + ((slen + 3) & ~3);
 		if (xdrlen > xdrleft) {
 			if (count == 0) {
 				/*
 				 * Can't even fit the first attribute name.
 				 */
 				status = nfserr_toosmall;
 				goto out;
 			}
 			eof = 0;
 			goto wreof;
 		}

 		left -= XATTR_USER_PREFIX_LEN;
 		sp += XATTR_USER_PREFIX_LEN;
 		if (nuser++ < offset)
 			goto contloop;


 		p = xdr_reserve_space(xdr, xdrlen);
 		if (!p) {
 			status = nfserr_resource;
 			goto out;
 		}

 		xdr_encode_opaque(p, sp, slen);

 		xdrleft -= xdrlen;
 		count++;
 contloop:
 		sp += slen + 1;
 		left -= slen + 1;
 	}

 	/*
 	 * If there were user attributes to copy, but we didn't copy
 	 * any, the offset was too large (e.g. the cookie was invalid).
 	 */
 	if (nuser > 0 && count == 0) {
 		status = nfserr_badcookie;
 		goto out;
 	}

 wreof:
 	p = xdr_reserve_space(xdr, 4);
 	if (!p) {
 		status = nfserr_resource;
 		goto out;
 	}
 	*p = cpu_to_be32(eof);

 	cookie = offset + count;

 	write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &cookie, 8);
 	tmp = cpu_to_be32(count);
 	write_bytes_to_xdr_buf(xdr->buf, count_offset, &tmp, 4);
 out:
 	if (listxattrs->lsxa_len)
 		kvfree(listxattrs->lsxa_buf);
 	return status;
 }

 static __be32
 nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_removexattr *removexattr)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 20);
 	if (!p)
 		return nfserr_resource;

 	p = encode_cinfo(p, &removexattr->rmxa_cinfo);
 	return 0;
 }

 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 const 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_noop,
 	[OP_FREE_STATEID]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_GET_DIR_DELEGATION]	= (nfsd4_enc)nfsd4_encode_noop,
 #ifdef CONFIG_NFSD_PNFS
 	[OP_GETDEVICEINFO]	= (nfsd4_enc)nfsd4_encode_getdeviceinfo,
 	[OP_GETDEVICELIST]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_LAYOUTCOMMIT]	= (nfsd4_enc)nfsd4_encode_layoutcommit,
 	[OP_LAYOUTGET]		= (nfsd4_enc)nfsd4_encode_layoutget,
 	[OP_LAYOUTRETURN]	= (nfsd4_enc)nfsd4_encode_layoutreturn,
 #else
 	[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,
 #endif
 	[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_test_stateid,
 	[OP_WANT_DELEGATION]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_DESTROY_CLIENTID]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_RECLAIM_COMPLETE]	= (nfsd4_enc)nfsd4_encode_noop,

 	/* NFSv4.2 operations */
 	[OP_ALLOCATE]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_COPY]		= (nfsd4_enc)nfsd4_encode_copy,
 	[OP_COPY_NOTIFY]	= (nfsd4_enc)nfsd4_encode_copy_notify,
 	[OP_DEALLOCATE]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_IO_ADVISE]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_LAYOUTERROR]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_LAYOUTSTATS]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_OFFLOAD_CANCEL]	= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_OFFLOAD_STATUS]	= (nfsd4_enc)nfsd4_encode_offload_status,
 	[OP_READ_PLUS]		= (nfsd4_enc)nfsd4_encode_read_plus,
 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,

 	/* RFC 8276 extended atributes operations */
 	[OP_GETXATTR]		= (nfsd4_enc)nfsd4_encode_getxattr,
 	[OP_SETXATTR]		= (nfsd4_enc)nfsd4_encode_setxattr,
 	[OP_LISTXATTRS]		= (nfsd4_enc)nfsd4_encode_listxattrs,
 	[OP_REMOVEXATTR]	= (nfsd4_enc)nfsd4_encode_removexattr,
 };

 /*
  * Calculate whether we still have space to encode repsize bytes.
  * There are two considerations:
  *     - For NFS versions >=4.1, the size of the reply must stay within
  *       session limits
  *     - For all NFS versions, we must stay within limited preallocated
  *       buffer space.
  *
  * This is called before the operation is processed, so can only provide
  * an upper estimate.  For some nonidempotent operations (such as
  * getattr), it's not necessarily a problem if that estimate is wrong,
  * as we can fail it after processing without significant side effects.
  */
 __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
 {
 	struct xdr_buf *buf = &resp->rqstp->rq_res;
 	struct nfsd4_slot *slot = resp->cstate.slot;

 	if (buf->len + respsize <= buf->buflen)
 		return nfs_ok;
 	if (!nfsd4_has_session(&resp->cstate))
 		return nfserr_resource;
 	if (slot->sl_flags & NFSD4_SLOT_CACHETHIS) {
 		WARN_ON_ONCE(1);
 		return nfserr_rep_too_big_to_cache;
 	}
 	return nfserr_rep_too_big;
 }

 void
 nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
 {
 	struct xdr_stream *xdr = resp->xdr;
 	struct nfs4_stateowner *so = resp->cstate.replay_owner;
 	struct svc_rqst *rqstp = resp->rqstp;
 	const struct nfsd4_operation *opdesc = op->opdesc;
 	int post_err_offset;
 	nfsd4_enc encoder;
 	__be32 *p;

 	p = xdr_reserve_space(xdr, 8);
 	if (!p) {
 		WARN_ON_ONCE(1);
 		return;
 	}
 	*p++ = cpu_to_be32(op->opnum);
 	post_err_offset = xdr->buf->len;

 	if (op->opnum == OP_ILLEGAL)
 		goto status;
 	if (op->status && opdesc &&
 			!(opdesc->op_flags & OP_NONTRIVIAL_ERROR_ENCODE))
 		goto status;
 	BUG_ON(op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
 	       !nfsd4_enc_ops[op->opnum]);
 	encoder = nfsd4_enc_ops[op->opnum];
 	op->status = encoder(resp, op->status, &op->u);
 	if (op->status)
 		trace_nfsd_compound_encode_err(rqstp, op->opnum, op->status);
 	if (opdesc && opdesc->op_release)
 		opdesc->op_release(&op->u);
 	xdr_commit_encode(xdr);

 	/* nfsd4_check_resp_size guarantees enough room for error status */
 	if (!op->status) {
 		int space_needed = 0;
 		if (!nfsd4_last_compound_op(rqstp))
 			space_needed = COMPOUND_ERR_SLACK_SPACE;
 		op->status = nfsd4_check_resp_size(resp, space_needed);
 	}
 	if (op->status == nfserr_resource && nfsd4_has_session(&resp->cstate)) {
 		struct nfsd4_slot *slot = resp->cstate.slot;

 		if (slot->sl_flags & NFSD4_SLOT_CACHETHIS)
 			op->status = nfserr_rep_too_big_to_cache;
 		else
 			op->status = nfserr_rep_too_big;
 	}
 	if (op->status == nfserr_resource ||
 	    op->status == nfserr_rep_too_big ||
 	    op->status == nfserr_rep_too_big_to_cache) {
 		/*
 		 * The operation may have already been encoded or
 		 * partially encoded.  No op returns anything additional
 		 * in the case of one of these three errors, so we can
 		 * just truncate back to after the status.  But it's a
 		 * bug if we had to do this on a non-idempotent op:
 		 */
 		warn_on_nonidempotent_op(op);
 		xdr_truncate_encode(xdr, post_err_offset);
 	}
 	if (so) {
 		int len = xdr->buf->len - post_err_offset;

 		so->so_replay.rp_status = op->status;
 		so->so_replay.rp_buflen = len;
 		read_bytes_from_xdr_buf(xdr->buf, post_err_offset,
 						so->so_replay.rp_buf, len);
 	}
 status:
 	/* Note that op->status is already in network byte order: */
 	write_bytes_to_xdr_buf(xdr->buf, post_err_offset - 4, &op->status, 4);
 }

 /*
  * 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.
  */
 void
 nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op)
 {
 	__be32 *p;
 	struct nfs4_replay *rp = op->replay;

 	p = xdr_reserve_space(xdr, 8 + rp->rp_buflen);
 	if (!p) {
 		WARN_ON_ONCE(1);
 		return;
 	}
 	*p++ = cpu_to_be32(op->opnum);
 	*p++ = rp->rp_status;  /* already xdr'ed */

 	p = xdr_encode_opaque_fixed(p, rp->rp_buf, rp->rp_buflen);
 }

 void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
 {
 	struct nfsd4_compoundargs *args = rqstp->rq_argp;

 	if (args->ops != args->iops) {
 		kfree(args->ops);
 		args->ops = args->iops;
 	}
 	while (args->to_free) {
 		struct svcxdr_tmpbuf *tb = args->to_free;
 		args->to_free = tb->next;
 		kfree(tb);
 	}
 }

 int
 nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd4_compoundargs *args = rqstp->rq_argp;

 	/* svcxdr_tmp_alloc */
 	args->to_free = NULL;

 	args->xdr = &rqstp->rq_arg_stream;
 	args->ops = args->iops;
 	args->rqstp = rqstp;

 	return nfsd4_decode_compound(args);
 }

 int
 nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	struct xdr_buf *buf = resp->xdr->buf;

 	WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
 				 buf->tail[0].iov_len);

 	*p = resp->cstate.status;

 	rqstp->rq_next_page = resp->xdr->page_ptr + 1;

 	p = resp->tagp;
 	*p++ = htonl(resp->taglen);
 	memcpy(p, resp->tag, resp->taglen);
 	p += XDR_QUADLEN(resp->taglen);
 	*p++ = htonl(resp->opcnt);

 	nfsd4_sequence_done(resp);
 	return 1;
 }