[PATCH] knfsd: Avoid excess stack usage in svc_tcp_recvfrom

[mirror_ubuntu-artful-kernel.git] / fs / nfsd / nfs3xdr.c

/*
 * linux/fs/nfsd/nfs3xdr.c
 *
 * XDR support for nfsd/protocol version 3.
 *
 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
 *
 * 2003-08-09 Jamie Lokier: Use htonl() for nanoseconds, not htons()!
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/nfs3.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/mm.h>
#include <linux/vfs.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/xdr3.h>

#define NFSDDBG_FACILITY		NFSDDBG_XDR

#ifdef NFSD_OPTIMIZE_SPACE
# define inline
#endif


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

/*
 * XDR functions for basic NFS types
 */
static inline u32 *
encode_time3(u32 *p, struct timespec *time)
{
	*p++ = htonl((u32) time->tv_sec); *p++ = htonl(time->tv_nsec);
	return p;
}

static inline u32 *
decode_time3(u32 *p, struct timespec *time)
{
	time->tv_sec = ntohl(*p++);
	time->tv_nsec = ntohl(*p++);
	return p;
}

static inline u32 *
decode_fh(u32 *p, struct svc_fh *fhp)
{
	unsigned int size;
	fh_init(fhp, NFS3_FHSIZE);
	size = ntohl(*p++);
	if (size > NFS3_FHSIZE)
		return NULL;

	memcpy(&fhp->fh_handle.fh_base, p, size);
	fhp->fh_handle.fh_size = size;
	return p + XDR_QUADLEN(size);
}

/* Helper function for NFSv3 ACL code */
u32 *nfs3svc_decode_fh(u32 *p, struct svc_fh *fhp)
{
	return decode_fh(p, fhp);
}

static inline u32 *
encode_fh(u32 *p, struct svc_fh *fhp)
{
	unsigned int size = fhp->fh_handle.fh_size;
	*p++ = htonl(size);
	if (size) p[XDR_QUADLEN(size)-1]=0;
	memcpy(p, &fhp->fh_handle.fh_base, size);
	return p + XDR_QUADLEN(size);
}

/*
 * Decode a file name and make sure that the path contains
 * no slashes or null bytes.
 */
static inline u32 *
decode_filename(u32 *p, char **namp, int *lenp)
{
	char		*name;
	int		i;

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

	return p;
}

static inline u32 *
decode_sattr3(u32 *p, struct iattr *iap)
{
	u32	tmp;

	iap->ia_valid = 0;

	if (*p++) {
		iap->ia_valid |= ATTR_MODE;
		iap->ia_mode = ntohl(*p++);
	}
	if (*p++) {
		iap->ia_valid |= ATTR_UID;
		iap->ia_uid = ntohl(*p++);
	}
	if (*p++) {
		iap->ia_valid |= ATTR_GID;
		iap->ia_gid = ntohl(*p++);
	}
	if (*p++) {
		u64	newsize;

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

static inline u32 *
encode_fattr3(struct svc_rqst *rqstp, u32 *p, struct svc_fh *fhp,
	      struct kstat *stat)
{
	struct dentry	*dentry = fhp->fh_dentry;
	struct timespec time;

	*p++ = htonl(nfs3_ftypes[(stat->mode & S_IFMT) >> 12]);
	*p++ = htonl((u32) stat->mode);
	*p++ = htonl((u32) stat->nlink);
	*p++ = htonl((u32) nfsd_ruid(rqstp, stat->uid));
	*p++ = htonl((u32) nfsd_rgid(rqstp, stat->gid));
	if (S_ISLNK(stat->mode) && stat->size > NFS3_MAXPATHLEN) {
		p = xdr_encode_hyper(p, (u64) NFS3_MAXPATHLEN);
	} else {
		p = xdr_encode_hyper(p, (u64) stat->size);
	}
	p = xdr_encode_hyper(p, ((u64)stat->blocks) << 9);
	*p++ = htonl((u32) MAJOR(stat->rdev));
	*p++ = htonl((u32) MINOR(stat->rdev));
	if (is_fsid(fhp, rqstp->rq_reffh))
		p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
	else
		p = xdr_encode_hyper(p, (u64) huge_encode_dev(stat->dev));
	p = xdr_encode_hyper(p, (u64) stat->ino);
	p = encode_time3(p, &stat->atime);
	lease_get_mtime(dentry->d_inode, &time); 
	p = encode_time3(p, &time);
	p = encode_time3(p, &stat->ctime);

	return p;
}

static inline u32 *
encode_saved_post_attr(struct svc_rqst *rqstp, u32 *p, struct svc_fh *fhp)
{
	struct inode	*inode = fhp->fh_dentry->d_inode;

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

	*p++ = htonl(nfs3_ftypes[(fhp->fh_post_mode & S_IFMT) >> 12]);
	*p++ = htonl((u32) fhp->fh_post_mode);
	*p++ = htonl((u32) fhp->fh_post_nlink);
	*p++ = htonl((u32) nfsd_ruid(rqstp, fhp->fh_post_uid));
	*p++ = htonl((u32) nfsd_rgid(rqstp, fhp->fh_post_gid));
	if (S_ISLNK(fhp->fh_post_mode) && fhp->fh_post_size > NFS3_MAXPATHLEN) {
		p = xdr_encode_hyper(p, (u64) NFS3_MAXPATHLEN);
	} else {
		p = xdr_encode_hyper(p, (u64) fhp->fh_post_size);
	}
	p = xdr_encode_hyper(p, ((u64)fhp->fh_post_blocks) << 9);
	*p++ = fhp->fh_post_rdev[0];
	*p++ = fhp->fh_post_rdev[1];
	if (is_fsid(fhp, rqstp->rq_reffh))
		p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
	else
		p = xdr_encode_hyper(p, (u64)huge_encode_dev(inode->i_sb->s_dev));
	p = xdr_encode_hyper(p, (u64) inode->i_ino);
	p = encode_time3(p, &fhp->fh_post_atime);
	p = encode_time3(p, &fhp->fh_post_mtime);
	p = encode_time3(p, &fhp->fh_post_ctime);

	return p;
}

/*
 * Encode post-operation attributes.
 * The inode may be NULL if the call failed because of a stale file
 * handle. In this case, no attributes are returned.
 */
static u32 *
encode_post_op_attr(struct svc_rqst *rqstp, u32 *p, struct svc_fh *fhp)
{
	struct dentry *dentry = fhp->fh_dentry;
	if (dentry && dentry->d_inode != NULL) {
	        int err;
		struct kstat stat;

		err = vfs_getattr(fhp->fh_export->ex_mnt, dentry, &stat);
		if (!err) {
			*p++ = xdr_one;		/* attributes follow */
			return encode_fattr3(rqstp, p, fhp, &stat);
		}
	}
	*p++ = xdr_zero;
	return p;
}

/* Helper for NFSv3 ACLs */
u32 *
nfs3svc_encode_post_op_attr(struct svc_rqst *rqstp, u32 *p, struct svc_fh *fhp)
{
	return encode_post_op_attr(rqstp, p, fhp);
}

/*
 * Enocde weak cache consistency data
 */
static u32 *
encode_wcc_data(struct svc_rqst *rqstp, u32 *p, struct svc_fh *fhp)
{
	struct dentry	*dentry = fhp->fh_dentry;

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


/*
 * XDR decode functions
 */
int
nfs3svc_decode_fhandle(struct svc_rqst *rqstp, u32 *p, struct nfsd_fhandle *args)
{
	if (!(p = decode_fh(p, &args->fh)))
		return 0;
	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_sattrargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_sattrargs *args)
{
	if (!(p = decode_fh(p, &args->fh))
	 || !(p = decode_sattr3(p, &args->attrs)))
		return 0;

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

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_diropargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_diropargs *args)
{
	if (!(p = decode_fh(p, &args->fh))
	 || !(p = decode_filename(p, &args->name, &args->len)))
		return 0;

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_accessargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_accessargs *args)
{
	if (!(p = decode_fh(p, &args->fh)))
		return 0;
	args->access = ntohl(*p++);

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_readargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readargs *args)
{
	unsigned int len;
	int v,pn;

	if (!(p = decode_fh(p, &args->fh))
	 || !(p = xdr_decode_hyper(p, &args->offset)))
		return 0;

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

	if (len > NFSSVC_MAXBLKSIZE)
		len = NFSSVC_MAXBLKSIZE;

	/* set up the kvec */
	v=0;
	while (len > 0) {
		pn = rqstp->rq_resused++;
		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_respages[pn]);
		rqstp->rq_vec[v].iov_len = len < PAGE_SIZE? len : PAGE_SIZE;
		len -= rqstp->rq_vec[v].iov_len;
		v++;
	}
	args->vlen = v;
	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_writeargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_writeargs *args)
{
	unsigned int len, v, hdr;

	if (!(p = decode_fh(p, &args->fh))
	 || !(p = xdr_decode_hyper(p, &args->offset)))
		return 0;

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

	hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;
	if (rqstp->rq_arg.len < hdr ||
	    rqstp->rq_arg.len - hdr < len)
		return 0;

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

	if (len > NFSSVC_MAXBLKSIZE)
		len = NFSSVC_MAXBLKSIZE;
	v=  0;
	while (len > rqstp->rq_vec[v].iov_len) {
		len -= rqstp->rq_vec[v].iov_len;
		v++;
		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);
		rqstp->rq_vec[v].iov_len = PAGE_SIZE;
	}
	rqstp->rq_vec[v].iov_len = len;
	args->vlen = v+1;

	return args->count == args->len && rqstp->rq_vec[0].iov_len > 0;
}

int
nfs3svc_decode_createargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_createargs *args)
{
	if (!(p = decode_fh(p, &args->fh))
	 || !(p = decode_filename(p, &args->name, &args->len)))
		return 0;

	switch (args->createmode = ntohl(*p++)) {
	case NFS3_CREATE_UNCHECKED:
	case NFS3_CREATE_GUARDED:
		if (!(p = decode_sattr3(p, &args->attrs)))
			return 0;
		break;
	case NFS3_CREATE_EXCLUSIVE:
		args->verf = p;
		p += 2;
		break;
	default:
		return 0;
	}

	return xdr_argsize_check(rqstp, p);
}
int
nfs3svc_decode_mkdirargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_createargs *args)
{
	if (!(p = decode_fh(p, &args->fh))
	 || !(p = decode_filename(p, &args->name, &args->len))
	 || !(p = decode_sattr3(p, &args->attrs)))
		return 0;

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_symlinkargs *args)
{
	unsigned int len;
	int avail;
	char *old, *new;
	struct kvec *vec;

	if (!(p = decode_fh(p, &args->ffh))
	 || !(p = decode_filename(p, &args->fname, &args->flen))
	 || !(p = decode_sattr3(p, &args->attrs))
		)
		return 0;
	/* now decode the pathname, which might be larger than the first page.
	 * As we have to check for nul's anyway, we copy it into a new page
	 * This page appears in the rq_res.pages list, but as pages_len is always
	 * 0, it won't get in the way
	 */
	len = ntohl(*p++);
	if (len == 0 || len > NFS3_MAXPATHLEN || len >= PAGE_SIZE)
		return 0;
	args->tname = new =
		page_address(rqstp->rq_respages[rqstp->rq_resused++]);
	args->tlen = len;
	/* first copy and check from the first page */
	old = (char*)p;
	vec = &rqstp->rq_arg.head[0];
	avail = vec->iov_len - (old - (char*)vec->iov_base);
	while (len && avail && *old) {
		*new++ = *old++;
		len--;
		avail--;
	}
	/* now copy next page if there is one */
	if (len && !avail && rqstp->rq_arg.page_len) {
		avail = rqstp->rq_arg.page_len;
		if (avail > PAGE_SIZE) avail = PAGE_SIZE;
		old = page_address(rqstp->rq_arg.pages[0]);
	}
	while (len && avail && *old) {
		*new++ = *old++;
		len--;
		avail--;
	}
	*new = '\0';
	if (len)
		return 0;

	return 1;
}

int
nfs3svc_decode_mknodargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_mknodargs *args)
{
	if (!(p = decode_fh(p, &args->fh))
	 || !(p = decode_filename(p, &args->name, &args->len)))
		return 0;

	args->ftype = ntohl(*p++);

	if (args->ftype == NF3BLK  || args->ftype == NF3CHR
	 || args->ftype == NF3SOCK || args->ftype == NF3FIFO) {
		if (!(p = decode_sattr3(p, &args->attrs)))
			return 0;
	}

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

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_renameargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_renameargs *args)
{
	if (!(p = decode_fh(p, &args->ffh))
	 || !(p = decode_filename(p, &args->fname, &args->flen))
	 || !(p = decode_fh(p, &args->tfh))
	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
		return 0;

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_readlinkargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readlinkargs *args)
{
	if (!(p = decode_fh(p, &args->fh)))
		return 0;
	args->buffer =
		page_address(rqstp->rq_respages[rqstp->rq_resused++]);

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_linkargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_linkargs *args)
{
	if (!(p = decode_fh(p, &args->ffh))
	 || !(p = decode_fh(p, &args->tfh))
	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
		return 0;

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readdirargs *args)
{
	if (!(p = decode_fh(p, &args->fh)))
		return 0;
	p = xdr_decode_hyper(p, &args->cookie);
	args->verf   = p; p += 2;
	args->dircount = ~0;
	args->count  = ntohl(*p++);

	if (args->count > PAGE_SIZE)
		args->count = PAGE_SIZE;

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

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_readdirplusargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readdirargs *args)
{
	int len, pn;

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

	len = (args->count > NFSSVC_MAXBLKSIZE) ? NFSSVC_MAXBLKSIZE :
						  args->count;
	args->count = len;

	while (len > 0) {
		pn = rqstp->rq_resused++;
		if (!args->buffer)
			args->buffer = page_address(rqstp->rq_respages[pn]);
		len -= PAGE_SIZE;
	}

	return xdr_argsize_check(rqstp, p);
}

int
nfs3svc_decode_commitargs(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_commitargs *args)
{
	if (!(p = decode_fh(p, &args->fh)))
		return 0;
	p = xdr_decode_hyper(p, &args->offset);
	args->count = ntohl(*p++);

	return xdr_argsize_check(rqstp, p);
}

/*
 * XDR encode functions
 */
/*
 * There must be an encoding function for void results so svc_process
 * will work properly.
 */
int
nfs3svc_encode_voidres(struct svc_rqst *rqstp, u32 *p, void *dummy)
{
	return xdr_ressize_check(rqstp, p);
}

/* GETATTR */
int
nfs3svc_encode_attrstat(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_attrstat *resp)
{
	if (resp->status == 0)
		p = encode_fattr3(rqstp, p, &resp->fh, &resp->stat);
	return xdr_ressize_check(rqstp, p);
}

/* SETATTR, REMOVE, RMDIR */
int
nfs3svc_encode_wccstat(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_attrstat *resp)
{
	p = encode_wcc_data(rqstp, p, &resp->fh);
	return xdr_ressize_check(rqstp, p);
}

/* LOOKUP */
int
nfs3svc_encode_diropres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_diropres *resp)
{
	if (resp->status == 0) {
		p = encode_fh(p, &resp->fh);
		p = encode_post_op_attr(rqstp, p, &resp->fh);
	}
	p = encode_post_op_attr(rqstp, p, &resp->dirfh);
	return xdr_ressize_check(rqstp, p);
}

/* ACCESS */
int
nfs3svc_encode_accessres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_accessres *resp)
{
	p = encode_post_op_attr(rqstp, p, &resp->fh);
	if (resp->status == 0)
		*p++ = htonl(resp->access);
	return xdr_ressize_check(rqstp, p);
}

/* READLINK */
int
nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readlinkres *resp)
{
	p = encode_post_op_attr(rqstp, p, &resp->fh);
	if (resp->status == 0) {
		*p++ = htonl(resp->len);
		xdr_ressize_check(rqstp, p);
		rqstp->rq_res.page_len = resp->len;
		if (resp->len & 3) {
			/* need to pad the tail */
			rqstp->rq_res.tail[0].iov_base = p;
			*p = 0;
			rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
		}
		return 1;
	} else
		return xdr_ressize_check(rqstp, p);
}

/* READ */
int
nfs3svc_encode_readres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readres *resp)
{
	p = encode_post_op_attr(rqstp, p, &resp->fh);
	if (resp->status == 0) {
		*p++ = htonl(resp->count);
		*p++ = htonl(resp->eof);
		*p++ = htonl(resp->count);	/* xdr opaque count */
		xdr_ressize_check(rqstp, p);
		/* now update rqstp->rq_res to reflect data aswell */
		rqstp->rq_res.page_len = resp->count;
		if (resp->count & 3) {
			/* need to pad the tail */
			rqstp->rq_res.tail[0].iov_base = p;
			*p = 0;
			rqstp->rq_res.tail[0].iov_len = 4 - (resp->count & 3);
		}
		return 1;
	} else
		return xdr_ressize_check(rqstp, p);
}

/* WRITE */
int
nfs3svc_encode_writeres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_writeres *resp)
{
	p = encode_wcc_data(rqstp, p, &resp->fh);
	if (resp->status == 0) {
		*p++ = htonl(resp->count);
		*p++ = htonl(resp->committed);
		*p++ = htonl(nfssvc_boot.tv_sec);
		*p++ = htonl(nfssvc_boot.tv_usec);
	}
	return xdr_ressize_check(rqstp, p);
}

/* CREATE, MKDIR, SYMLINK, MKNOD */
int
nfs3svc_encode_createres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_diropres *resp)
{
	if (resp->status == 0) {
		*p++ = xdr_one;
		p = encode_fh(p, &resp->fh);
		p = encode_post_op_attr(rqstp, p, &resp->fh);
	}
	p = encode_wcc_data(rqstp, p, &resp->dirfh);
	return xdr_ressize_check(rqstp, p);
}

/* RENAME */
int
nfs3svc_encode_renameres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_renameres *resp)
{
	p = encode_wcc_data(rqstp, p, &resp->ffh);
	p = encode_wcc_data(rqstp, p, &resp->tfh);
	return xdr_ressize_check(rqstp, p);
}

/* LINK */
int
nfs3svc_encode_linkres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_linkres *resp)
{
	p = encode_post_op_attr(rqstp, p, &resp->fh);
	p = encode_wcc_data(rqstp, p, &resp->tfh);
	return xdr_ressize_check(rqstp, p);
}

/* READDIR */
int
nfs3svc_encode_readdirres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_readdirres *resp)
{
	p = encode_post_op_attr(rqstp, p, &resp->fh);

	if (resp->status == 0) {
		/* stupid readdir cookie */
		memcpy(p, resp->verf, 8); p += 2;
		xdr_ressize_check(rqstp, p);
		if (rqstp->rq_res.head[0].iov_len + (2<<2) > PAGE_SIZE)
			return 1; /*No room for trailer */
		rqstp->rq_res.page_len = (resp->count) << 2;

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

static inline u32 *
encode_entry_baggage(struct nfsd3_readdirres *cd, u32 *p, const char *name,
	     int namlen, ino_t ino)
{
	*p++ = xdr_one;				 /* mark entry present */
	p    = xdr_encode_hyper(p, ino);	 /* file id */
	p    = xdr_encode_array(p, name, namlen);/* name length & name */

	cd->offset = p;				/* remember pointer */
	p = xdr_encode_hyper(p, NFS_OFFSET_MAX);/* offset of next entry */

	return p;
}

static inline u32 *
encode_entryplus_baggage(struct nfsd3_readdirres *cd, u32 *p,
		struct svc_fh *fhp)
{
		p = encode_post_op_attr(cd->rqstp, p, fhp);
		*p++ = xdr_one;			/* yes, a file handle follows */
		p = encode_fh(p, fhp);
		fh_put(fhp);
		return p;
}

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

	dparent = cd->fh.fh_dentry;
	exp  = cd->fh.fh_export;

	fh_init(fhp, NFS3_FHSIZE);
	if (isdotent(name, namlen)) {
		if (namlen == 2) {
			dchild = dget_parent(dparent);
			if (dchild == dparent) {
				/* filesystem root - cannot return filehandle for ".." */
				dput(dchild);
				return 1;
			}
		} else
			dchild = dget(dparent);
	} else
		dchild = lookup_one_len(name, dparent, namlen);
	if (IS_ERR(dchild))
		return 1;
	if (d_mountpoint(dchild) ||
	    fh_compose(fhp, exp, dchild, &cd->fh) != 0 ||
	    !dchild->d_inode)
		rv = 1;
	dput(dchild);
	return rv;
}

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

#define NFS3_ENTRY_BAGGAGE	(2 + 1 + 2 + 1)
#define NFS3_ENTRYPLUS_BAGGAGE	(1 + 21 + 1 + (NFS3_FHSIZE >> 2))
static int
encode_entry(struct readdir_cd *ccd, const char *name,
	     int namlen, off_t offset, ino_t ino, unsigned int d_type, int plus)
{
	struct nfsd3_readdirres *cd = container_of(ccd, struct nfsd3_readdirres,
		       					common);
	u32		*p = cd->buffer;
	caddr_t		curr_page_addr = NULL;
	int		pn;		/* current page number */
	int		slen;		/* string (name) length */
	int		elen;		/* estimated entry length in words */
	int		num_entry_words = 0;	/* actual number of words */

	if (cd->offset) {
		u64 offset64 = offset;

		if (unlikely(cd->offset1)) {
			/* we ended up with offset on a page boundary */
			*cd->offset = htonl(offset64 >> 32);
			*cd->offset1 = htonl(offset64 & 0xffffffff);
			cd->offset1 = NULL;
		} else {
			xdr_encode_hyper(cd->offset, (u64) offset);
		}
	}

	/*
	dprintk("encode_entry(%.*s @%ld%s)\n",
		namlen, name, (long) offset, plus? " plus" : "");
	 */

	/* truncate filename if too long */
	if (namlen > NFS3_MAXNAMLEN)
		namlen = NFS3_MAXNAMLEN;

	slen = XDR_QUADLEN(namlen);
	elen = slen + NFS3_ENTRY_BAGGAGE
		+ (plus? NFS3_ENTRYPLUS_BAGGAGE : 0);

	if (cd->buflen < elen) {
		cd->common.err = nfserr_toosmall;
		return -EINVAL;
	}

	/* determine which page in rq_respages[] we are currently filling */
	for (pn=1; pn < cd->rqstp->rq_resused; pn++) {
		curr_page_addr = page_address(cd->rqstp->rq_respages[pn]);

		if (((caddr_t)cd->buffer >= curr_page_addr) &&
		    ((caddr_t)cd->buffer <  curr_page_addr + PAGE_SIZE))
			break;
	}

	if ((caddr_t)(cd->buffer + elen) < (curr_page_addr + PAGE_SIZE)) {
		/* encode entry in current page */

		p = encode_entry_baggage(cd, p, name, namlen, ino);

		/* throw in readdirplus baggage */
		if (plus) {
			struct svc_fh	fh;

			if (compose_entry_fh(cd, &fh, name, namlen) > 0) {
				*p++ = 0;
				*p++ = 0;
			} else
				p = encode_entryplus_baggage(cd, p, &fh);
		}
		num_entry_words = p - cd->buffer;
	} else if (cd->rqstp->rq_respages[pn+1] != NULL) {
		/* temporarily encode entry into next page, then move back to
		 * current and next page in rq_respages[] */
		u32 *p1, *tmp;
		int len1, len2;

		/* grab next page for temporary storage of entry */
		p1 = tmp = page_address(cd->rqstp->rq_respages[pn+1]);

		p1 = encode_entry_baggage(cd, p1, name, namlen, ino);

		/* throw in readdirplus baggage */
		if (plus) {
			struct svc_fh	fh;

			if (compose_entry_fh(cd, &fh, name, namlen) > 0) {
				/* zero out the filehandle */
				*p1++ = 0;
				*p1++ = 0;
			} else
				p1 = encode_entryplus_baggage(cd, p1, &fh);
		}

		/* determine entry word length and lengths to go in pages */
		num_entry_words = p1 - tmp;
		len1 = curr_page_addr + PAGE_SIZE - (caddr_t)cd->buffer;
		if ((num_entry_words << 2) < len1) {
			/* the actual number of words in the entry is less
			 * than elen and can still fit in the current page
			 */
			memmove(p, tmp, num_entry_words << 2);
			p += num_entry_words;

			/* update offset */
			cd->offset = cd->buffer + (cd->offset - tmp);
		} else {
			unsigned int offset_r = (cd->offset - tmp) << 2;

			/* update pointer to offset location.
			 * This is a 64bit quantity, so we need to
			 * deal with 3 cases:
			 *  -	entirely in first page
			 *  -	entirely in second page
			 *  -	4 bytes in each page
			 */
			if (offset_r + 8 <= len1) {
				cd->offset = p + (cd->offset - tmp);
			} else if (offset_r >= len1) {
				cd->offset -= len1 >> 2;
			} else {
				/* sitting on the fence */
				BUG_ON(offset_r != len1 - 4);
				cd->offset = p + (cd->offset - tmp);
				cd->offset1 = tmp;
			}

			len2 = (num_entry_words << 2) - len1;

			/* move from temp page to current and next pages */
			memmove(p, tmp, len1);
			memmove(tmp, (caddr_t)tmp+len1, len2);

			p = tmp + (len2 >> 2);
		}
	}
	else {
		cd->common.err = nfserr_toosmall;
		return -EINVAL;
	}

	cd->buflen -= num_entry_words;
	cd->buffer = p;
	cd->common.err = nfs_ok;
	return 0;

}

int
nfs3svc_encode_entry(struct readdir_cd *cd, const char *name,
		     int namlen, loff_t offset, ino_t ino, unsigned int d_type)
{
	return encode_entry(cd, name, namlen, offset, ino, d_type, 0);
}

int
nfs3svc_encode_entry_plus(struct readdir_cd *cd, const char *name,
			  int namlen, loff_t offset, ino_t ino, unsigned int d_type)
{
	return encode_entry(cd, name, namlen, offset, ino, d_type, 1);
}

/* FSSTAT */
int
nfs3svc_encode_fsstatres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_fsstatres *resp)
{
	struct kstatfs	*s = &resp->stats;
	u64		bs = s->f_bsize;

	*p++ = xdr_zero;	/* no post_op_attr */

	if (resp->status == 0) {
		p = xdr_encode_hyper(p, bs * s->f_blocks);	/* total bytes */
		p = xdr_encode_hyper(p, bs * s->f_bfree);	/* free bytes */
		p = xdr_encode_hyper(p, bs * s->f_bavail);	/* user available bytes */
		p = xdr_encode_hyper(p, s->f_files);	/* total inodes */
		p = xdr_encode_hyper(p, s->f_ffree);	/* free inodes */
		p = xdr_encode_hyper(p, s->f_ffree);	/* user available inodes */
		*p++ = htonl(resp->invarsec);	/* mean unchanged time */
	}
	return xdr_ressize_check(rqstp, p);
}

/* FSINFO */
int
nfs3svc_encode_fsinfores(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_fsinfores *resp)
{
	*p++ = xdr_zero;	/* no post_op_attr */

	if (resp->status == 0) {
		*p++ = htonl(resp->f_rtmax);
		*p++ = htonl(resp->f_rtpref);
		*p++ = htonl(resp->f_rtmult);
		*p++ = htonl(resp->f_wtmax);
		*p++ = htonl(resp->f_wtpref);
		*p++ = htonl(resp->f_wtmult);
		*p++ = htonl(resp->f_dtpref);
		p = xdr_encode_hyper(p, resp->f_maxfilesize);
		*p++ = xdr_one;
		*p++ = xdr_zero;
		*p++ = htonl(resp->f_properties);
	}

	return xdr_ressize_check(rqstp, p);
}

/* PATHCONF */
int
nfs3svc_encode_pathconfres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_pathconfres *resp)
{
	*p++ = xdr_zero;	/* no post_op_attr */

	if (resp->status == 0) {
		*p++ = htonl(resp->p_link_max);
		*p++ = htonl(resp->p_name_max);
		*p++ = htonl(resp->p_no_trunc);
		*p++ = htonl(resp->p_chown_restricted);
		*p++ = htonl(resp->p_case_insensitive);
		*p++ = htonl(resp->p_case_preserving);
	}

	return xdr_ressize_check(rqstp, p);
}

/* COMMIT */
int
nfs3svc_encode_commitres(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_commitres *resp)
{
	p = encode_wcc_data(rqstp, p, &resp->fh);
	/* Write verifier */
	if (resp->status == 0) {
		*p++ = htonl(nfssvc_boot.tv_sec);
		*p++ = htonl(nfssvc_boot.tv_usec);
	}
	return xdr_ressize_check(rqstp, p);
}

/*
 * XDR release functions
 */
int
nfs3svc_release_fhandle(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_attrstat *resp)
{
	fh_put(&resp->fh);
	return 1;
}

int
nfs3svc_release_fhandle2(struct svc_rqst *rqstp, u32 *p,
					struct nfsd3_fhandle_pair *resp)
{
	fh_put(&resp->fh1);
	fh_put(&resp->fh2);
	return 1;
}