// SPDX-License-Identifier: GPL-2.0
/*
 * 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/namei.h>
#include <linux/sunrpc/svc_xprt.h>
#include "xdr3.h"
#include "auth.h"
#include "netns.h"
#include "vfs.h"

/*
 * Force construction of an empty post-op attr
 */
static const struct svc_fh nfs3svc_null_fh = {
        .fh_no_wcc      = true,
};

/*
 * time_delta. {1, 0} means the server is accurate only
 * to the nearest second.
 */
static const struct timespec64 nfs3svc_time_delta = {
        .tv_sec         = 1,
        .tv_nsec        = 0,
};

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


/*
 * Basic NFSv3 data types (RFC 1813 Sections 2.5 and 2.6)
 */

static __be32 *
encode_nfstime3(__be32 *p, const struct timespec64 *time)
{
        *p++ = cpu_to_be32((u32)time->tv_sec);
        *p++ = cpu_to_be32(time->tv_nsec);

        return p;
}

static bool
svcxdr_decode_nfstime3(struct xdr_stream *xdr, struct timespec64 *timep)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, XDR_UNIT * 2);
        if (!p)
                return false;
        timep->tv_sec = be32_to_cpup(p++);
        timep->tv_nsec = be32_to_cpup(p);

        return true;
}

/**
 * svcxdr_decode_nfs_fh3 - Decode an NFSv3 file handle
 * @xdr: XDR stream positioned at an undecoded NFSv3 FH
 * @fhp: OUT: filled-in server file handle
 *
 * Return values:
 *  %false: The encoded file handle was not valid
 *  %true: @fhp has been initialized
 */
bool
svcxdr_decode_nfs_fh3(struct xdr_stream *xdr, struct svc_fh *fhp)
{
        __be32 *p;
        u32 size;

        if (xdr_stream_decode_u32(xdr, &size) < 0)
                return false;
        if (size == 0 || size > NFS3_FHSIZE)
                return false;
        p = xdr_inline_decode(xdr, size);
        if (!p)
                return false;
        fh_init(fhp, NFS3_FHSIZE);
        fhp->fh_handle.fh_size = size;
        memcpy(&fhp->fh_handle.fh_raw, p, size);

        return true;
}

/**
 * svcxdr_encode_nfsstat3 - Encode an NFSv3 status code
 * @xdr: XDR stream
 * @status: status value to encode
 *
 * Return values:
 *   %false: Send buffer space was exhausted
 *   %true: Success
 */
bool
svcxdr_encode_nfsstat3(struct xdr_stream *xdr, __be32 status)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, sizeof(status));
        if (!p)
                return false;
        *p = status;

        return true;
}

static bool
svcxdr_encode_nfs_fh3(struct xdr_stream *xdr, const struct svc_fh *fhp)
{
        u32 size = fhp->fh_handle.fh_size;
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT + size);
        if (!p)
                return false;
        *p++ = cpu_to_be32(size);
        if (size)
                p[XDR_QUADLEN(size) - 1] = 0;
        memcpy(p, &fhp->fh_handle.fh_raw, size);

        return true;
}

static bool
svcxdr_encode_post_op_fh3(struct xdr_stream *xdr, const struct svc_fh *fhp)
{
        if (xdr_stream_encode_item_present(xdr) < 0)
                return false;
        if (!svcxdr_encode_nfs_fh3(xdr, fhp))
                return false;

        return true;
}

static bool
svcxdr_encode_cookieverf3(struct xdr_stream *xdr, const __be32 *verf)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS3_COOKIEVERFSIZE);
        if (!p)
                return false;
        memcpy(p, verf, NFS3_COOKIEVERFSIZE);

        return true;
}

static bool
svcxdr_encode_writeverf3(struct xdr_stream *xdr, const __be32 *verf)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS3_WRITEVERFSIZE);
        if (!p)
                return false;
        memcpy(p, verf, NFS3_WRITEVERFSIZE);

        return true;
}

static bool
svcxdr_decode_filename3(struct xdr_stream *xdr, char **name, unsigned int *len)
{
        u32 size, i;
        __be32 *p;
        char *c;

        if (xdr_stream_decode_u32(xdr, &size) < 0)
                return false;
        if (size == 0 || size > NFS3_MAXNAMLEN)
                return false;
        p = xdr_inline_decode(xdr, size);
        if (!p)
                return false;

        *len = size;
        *name = (char *)p;
        for (i = 0, c = *name; i < size; i++, c++) {
                if (*c == '\0' || *c == '/')
                        return false;
        }

        return true;
}

static bool
svcxdr_decode_diropargs3(struct xdr_stream *xdr, struct svc_fh *fhp,
                         char **name, unsigned int *len)
{
        return svcxdr_decode_nfs_fh3(xdr, fhp) &&
                svcxdr_decode_filename3(xdr, name, len);
}

static bool
svcxdr_decode_sattr3(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                     struct iattr *iap)
{
        u32 set_it;

        iap->ia_valid = 0;

        if (xdr_stream_decode_bool(xdr, &set_it) < 0)
                return false;
        if (set_it) {
                u32 mode;

                if (xdr_stream_decode_u32(xdr, &mode) < 0)
                        return false;
                iap->ia_valid |= ATTR_MODE;
                iap->ia_mode = mode;
        }
        if (xdr_stream_decode_bool(xdr, &set_it) < 0)
                return false;
        if (set_it) {
                u32 uid;

                if (xdr_stream_decode_u32(xdr, &uid) < 0)
                        return false;
                iap->ia_uid = make_kuid(nfsd_user_namespace(rqstp), uid);
                if (uid_valid(iap->ia_uid))
                        iap->ia_valid |= ATTR_UID;
        }
        if (xdr_stream_decode_bool(xdr, &set_it) < 0)
                return false;
        if (set_it) {
                u32 gid;

                if (xdr_stream_decode_u32(xdr, &gid) < 0)
                        return false;
                iap->ia_gid = make_kgid(nfsd_user_namespace(rqstp), gid);
                if (gid_valid(iap->ia_gid))
                        iap->ia_valid |= ATTR_GID;
        }
        if (xdr_stream_decode_bool(xdr, &set_it) < 0)
                return false;
        if (set_it) {
                u64 newsize;

                if (xdr_stream_decode_u64(xdr, &newsize) < 0)
                        return false;
                iap->ia_valid |= ATTR_SIZE;
                iap->ia_size = newsize;
        }
        if (xdr_stream_decode_u32(xdr, &set_it) < 0)
                return false;
        switch (set_it) {
        case DONT_CHANGE:
                break;
        case SET_TO_SERVER_TIME:
                iap->ia_valid |= ATTR_ATIME;
                break;
        case SET_TO_CLIENT_TIME:
                if (!svcxdr_decode_nfstime3(xdr, &iap->ia_atime))
                        return false;
                iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
                break;
        default:
                return false;
        }
        if (xdr_stream_decode_u32(xdr, &set_it) < 0)
                return false;
        switch (set_it) {
        case DONT_CHANGE:
                break;
        case SET_TO_SERVER_TIME:
                iap->ia_valid |= ATTR_MTIME;
                break;
        case SET_TO_CLIENT_TIME:
                if (!svcxdr_decode_nfstime3(xdr, &iap->ia_mtime))
                        return false;
                iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
                break;
        default:
                return false;
        }

        return true;
}

static bool
svcxdr_decode_sattrguard3(struct xdr_stream *xdr, struct nfsd3_sattrargs *args)
{
        __be32 *p;
        u32 check;

        if (xdr_stream_decode_bool(xdr, &check) < 0)
                return false;
        if (check) {
                p = xdr_inline_decode(xdr, XDR_UNIT * 2);
                if (!p)
                        return false;
                args->check_guard = 1;
                args->guardtime = be32_to_cpup(p);
        } else
                args->check_guard = 0;

        return true;
}

static bool
svcxdr_decode_specdata3(struct xdr_stream *xdr, struct nfsd3_mknodargs *args)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, XDR_UNIT * 2);
        if (!p)
                return false;
        args->major = be32_to_cpup(p++);
        args->minor = be32_to_cpup(p);

        return true;
}

static bool
svcxdr_decode_devicedata3(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                          struct nfsd3_mknodargs *args)
{
        return svcxdr_decode_sattr3(rqstp, xdr, &args->attrs) &&
                svcxdr_decode_specdata3(xdr, args);
}

static bool
svcxdr_encode_fattr3(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                     const struct svc_fh *fhp, const struct kstat *stat)
{
        struct user_namespace *userns = nfsd_user_namespace(rqstp);
        __be32 *p;
        u64 fsid;

        p = xdr_reserve_space(xdr, XDR_UNIT * 21);
        if (!p)
                return false;

        *p++ = cpu_to_be32(nfs3_ftypes[(stat->mode & S_IFMT) >> 12]);
        *p++ = cpu_to_be32((u32)(stat->mode & S_IALLUGO));
        *p++ = cpu_to_be32((u32)stat->nlink);
        *p++ = cpu_to_be32((u32)from_kuid_munged(userns, stat->uid));
        *p++ = cpu_to_be32((u32)from_kgid_munged(userns, 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);

        /* used */
        p = xdr_encode_hyper(p, ((u64)stat->blocks) << 9);

        /* rdev */
        *p++ = cpu_to_be32((u32)MAJOR(stat->rdev));
        *p++ = cpu_to_be32((u32)MINOR(stat->rdev));

        switch(fsid_source(fhp)) {
        case FSIDSOURCE_FSID:
                fsid = (u64)fhp->fh_export->ex_fsid;
                break;
        case FSIDSOURCE_UUID:
                fsid = ((u64 *)fhp->fh_export->ex_uuid)[0];
                fsid ^= ((u64 *)fhp->fh_export->ex_uuid)[1];
                break;
        default:
                fsid = (u64)huge_encode_dev(fhp->fh_dentry->d_sb->s_dev);
        }
        p = xdr_encode_hyper(p, fsid);

        /* fileid */
        p = xdr_encode_hyper(p, stat->ino);

        p = encode_nfstime3(p, &stat->atime);
        p = encode_nfstime3(p, &stat->mtime);
        encode_nfstime3(p, &stat->ctime);

        return true;
}

static bool
svcxdr_encode_wcc_attr(struct xdr_stream *xdr, const struct svc_fh *fhp)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 6);
        if (!p)
                return false;
        p = xdr_encode_hyper(p, (u64)fhp->fh_pre_size);
        p = encode_nfstime3(p, &fhp->fh_pre_mtime);
        encode_nfstime3(p, &fhp->fh_pre_ctime);

        return true;
}

static bool
svcxdr_encode_pre_op_attr(struct xdr_stream *xdr, const struct svc_fh *fhp)
{
        if (!fhp->fh_pre_saved) {
                if (xdr_stream_encode_item_absent(xdr) < 0)
                        return false;
                return true;
        }

        if (xdr_stream_encode_item_present(xdr) < 0)
                return false;
        return svcxdr_encode_wcc_attr(xdr, fhp);
}

/**
 * svcxdr_encode_post_op_attr - Encode NFSv3 post-op attributes
 * @rqstp: Context of a completed RPC transaction
 * @xdr: XDR stream
 * @fhp: File handle to encode
 *
 * Return values:
 *   %false: Send buffer space was exhausted
 *   %true: Success
 */
bool
svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                           const struct svc_fh *fhp)
{
        struct dentry *dentry = fhp->fh_dentry;
        struct kstat stat;

        /*
         * The inode may be NULL if the call failed because of a
         * stale file handle. In this case, no attributes are
         * returned.
         */
        if (fhp->fh_no_wcc || !dentry || !d_really_is_positive(dentry))
                goto no_post_op_attrs;
        if (fh_getattr(fhp, &stat) != nfs_ok)
                goto no_post_op_attrs;

        if (xdr_stream_encode_item_present(xdr) < 0)
                return false;
        lease_get_mtime(d_inode(dentry), &stat.mtime);
        if (!svcxdr_encode_fattr3(rqstp, xdr, fhp, &stat))
                return false;

        return true;

no_post_op_attrs:
        return xdr_stream_encode_item_absent(xdr) > 0;
}

/*
 * Encode weak cache consistency data
 */
static bool
svcxdr_encode_wcc_data(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                       const struct svc_fh *fhp)
{
        struct dentry *dentry = fhp->fh_dentry;

        if (!dentry || !d_really_is_positive(dentry) || !fhp->fh_post_saved)
                goto neither;

        /* before */
        if (!svcxdr_encode_pre_op_attr(xdr, fhp))
                return false;

        /* after */
        if (xdr_stream_encode_item_present(xdr) < 0)
                return false;
        if (!svcxdr_encode_fattr3(rqstp, xdr, fhp, &fhp->fh_post_attr))
                return false;

        return true;

neither:
        if (xdr_stream_encode_item_absent(xdr) < 0)
                return false;
        if (!svcxdr_encode_post_op_attr(rqstp, xdr, fhp))
                return false;

        return true;
}

/*
 * XDR decode functions
 */

bool
nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd_fhandle *args = rqstp->rq_argp;

        return svcxdr_decode_nfs_fh3(xdr, &args->fh);
}

bool
nfs3svc_decode_sattrargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_sattrargs *args = rqstp->rq_argp;

        return svcxdr_decode_nfs_fh3(xdr, &args->fh) &&
                svcxdr_decode_sattr3(rqstp, xdr, &args->attrs) &&
                svcxdr_decode_sattrguard3(xdr, args);
}

bool
nfs3svc_decode_diropargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_diropargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs3(xdr, &args->fh, &args->name, &args->len);
}

bool
nfs3svc_decode_accessargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_accessargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u32(xdr, &args->access) < 0)
                return false;

        return true;
}

bool
nfs3svc_decode_readargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u64(xdr, &args->offset) < 0)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return false;

        return true;
}

bool
nfs3svc_decode_writeargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_writeargs *args = rqstp->rq_argp;
        u32 max_blocksize = svc_max_payload(rqstp);

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u64(xdr, &args->offset) < 0)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->stable) < 0)
                return false;

        /* opaque data */
        if (xdr_stream_decode_u32(xdr, &args->len) < 0)
                return false;

        /* request sanity */
        if (args->count != args->len)
                return false;
        if (args->count > max_blocksize) {
                args->count = max_blocksize;
                args->len = max_blocksize;
        }
        if (!xdr_stream_subsegment(xdr, &args->payload, args->count))
                return false;

        return true;
}

bool
nfs3svc_decode_createargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_createargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_diropargs3(xdr, &args->fh, &args->name, &args->len))
                return false;
        if (xdr_stream_decode_u32(xdr, &args->createmode) < 0)
                return false;
        switch (args->createmode) {
        case NFS3_CREATE_UNCHECKED:
        case NFS3_CREATE_GUARDED:
                return svcxdr_decode_sattr3(rqstp, xdr, &args->attrs);
        case NFS3_CREATE_EXCLUSIVE:
                args->verf = xdr_inline_decode(xdr, NFS3_CREATEVERFSIZE);
                if (!args->verf)
                        return false;
                break;
        default:
                return false;
        }
        return true;
}

bool
nfs3svc_decode_mkdirargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_createargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs3(xdr, &args->fh,
                                        &args->name, &args->len) &&
                svcxdr_decode_sattr3(rqstp, xdr, &args->attrs);
}

bool
nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_symlinkargs *args = rqstp->rq_argp;
        struct kvec *head = rqstp->rq_arg.head;
        struct kvec *tail = rqstp->rq_arg.tail;
        size_t remaining;

        if (!svcxdr_decode_diropargs3(xdr, &args->ffh, &args->fname, &args->flen))
                return false;
        if (!svcxdr_decode_sattr3(rqstp, xdr, &args->attrs))
                return false;
        if (xdr_stream_decode_u32(xdr, &args->tlen) < 0)
                return false;

        /* request sanity */
        remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
        remaining -= xdr_stream_pos(xdr);
        if (remaining < xdr_align_size(args->tlen))
                return false;

        args->first.iov_base = xdr->p;
        args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);

        return true;
}

bool
nfs3svc_decode_mknodargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_mknodargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_diropargs3(xdr, &args->fh, &args->name, &args->len))
                return false;
        if (xdr_stream_decode_u32(xdr, &args->ftype) < 0)
                return false;
        switch (args->ftype) {
        case NF3CHR:
        case NF3BLK:
                return svcxdr_decode_devicedata3(rqstp, xdr, args);
        case NF3SOCK:
        case NF3FIFO:
                return svcxdr_decode_sattr3(rqstp, xdr, &args->attrs);
        case NF3REG:
        case NF3DIR:
        case NF3LNK:
                /* Valid XDR but illegal file types */
                break;
        default:
                return false;
        }

        return true;
}

bool
nfs3svc_decode_renameargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_renameargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs3(xdr, &args->ffh,
                                        &args->fname, &args->flen) &&
                svcxdr_decode_diropargs3(xdr, &args->tfh,
                                         &args->tname, &args->tlen);
}

bool
nfs3svc_decode_linkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_linkargs *args = rqstp->rq_argp;

        return svcxdr_decode_nfs_fh3(xdr, &args->ffh) &&
                svcxdr_decode_diropargs3(xdr, &args->tfh,
                                         &args->tname, &args->tlen);
}

bool
nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readdirargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u64(xdr, &args->cookie) < 0)
                return false;
        args->verf = xdr_inline_decode(xdr, NFS3_COOKIEVERFSIZE);
        if (!args->verf)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return false;

        return true;
}

bool
nfs3svc_decode_readdirplusargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readdirargs *args = rqstp->rq_argp;
        u32 dircount;

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u64(xdr, &args->cookie) < 0)
                return false;
        args->verf = xdr_inline_decode(xdr, NFS3_COOKIEVERFSIZE);
        if (!args->verf)
                return false;
        /* dircount is ignored */
        if (xdr_stream_decode_u32(xdr, &dircount) < 0)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return false;

        return true;
}

bool
nfs3svc_decode_commitargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_commitargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
                return false;
        if (xdr_stream_decode_u64(xdr, &args->offset) < 0)
                return false;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return false;

        return true;
}

/*
 * XDR encode functions
 */

/* GETATTR */
bool
nfs3svc_encode_getattrres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_attrstat *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                lease_get_mtime(d_inode(resp->fh.fh_dentry), &resp->stat.mtime);
                if (!svcxdr_encode_fattr3(rqstp, xdr, &resp->fh, &resp->stat))
                        return false;
                break;
        }

        return true;
}

/* SETATTR, REMOVE, RMDIR */
bool
nfs3svc_encode_wccstat(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_attrstat *resp = rqstp->rq_resp;

        return svcxdr_encode_nfsstat3(xdr, resp->status) &&
                svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh);
}

/* LOOKUP */
bool
nfs3svc_encode_lookupres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_diropres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_nfs_fh3(xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
                        return false;
        }

        return true;
}

/* ACCESS */
bool
nfs3svc_encode_accessres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_accessres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->access) < 0)
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

/* READLINK */
bool
nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readlinkres *resp = rqstp->rq_resp;
        struct kvec *head = rqstp->rq_res.head;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->len) < 0)
                        return false;
                xdr_write_pages(xdr, resp->pages, 0, resp->len);
                if (svc_encode_result_payload(rqstp, head->iov_len, resp->len) < 0)
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

/* READ */
bool
nfs3svc_encode_readres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readres *resp = rqstp->rq_resp;
        struct kvec *head = rqstp->rq_res.head;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->count) < 0)
                        return false;
                if (xdr_stream_encode_bool(xdr, resp->eof) < 0)
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->count) < 0)
                        return false;
                xdr_write_pages(xdr, resp->pages, rqstp->rq_res.page_base,
                                resp->count);
                if (svc_encode_result_payload(rqstp, head->iov_len, resp->count) < 0)
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

/* WRITE */
bool
nfs3svc_encode_writeres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_writeres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh))
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->count) < 0)
                        return false;
                if (xdr_stream_encode_u32(xdr, resp->committed) < 0)
                        return false;
                if (!svcxdr_encode_writeverf3(xdr, resp->verf))
                        return false;
                break;
        default:
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

/* CREATE, MKDIR, SYMLINK, MKNOD */
bool
nfs3svc_encode_createres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_diropres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_fh3(xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->dirfh))
                        return false;
                break;
        default:
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->dirfh))
                        return false;
        }

        return true;
}

/* RENAME */
bool
nfs3svc_encode_renameres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_renameres *resp = rqstp->rq_resp;

        return svcxdr_encode_nfsstat3(xdr, resp->status) &&
                svcxdr_encode_wcc_data(rqstp, xdr, &resp->ffh) &&
                svcxdr_encode_wcc_data(rqstp, xdr, &resp->tfh);
}

/* LINK */
bool
nfs3svc_encode_linkres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_linkres *resp = rqstp->rq_resp;

        return svcxdr_encode_nfsstat3(xdr, resp->status) &&
                svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh) &&
                svcxdr_encode_wcc_data(rqstp, xdr, &resp->tfh);
}

/* READDIR */
bool
nfs3svc_encode_readdirres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_readdirres *resp = rqstp->rq_resp;
        struct xdr_buf *dirlist = &resp->dirlist;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_cookieverf3(xdr, resp->verf))
                        return false;
                xdr_write_pages(xdr, dirlist->pages, 0, dirlist->len);
                /* no more entries */
                if (xdr_stream_encode_item_absent(xdr) < 0)
                        return false;
                if (xdr_stream_encode_bool(xdr, resp->common.err == nfserr_eof) < 0)
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

static __be32
compose_entry_fh(struct nfsd3_readdirres *cd, struct svc_fh *fhp,
                 const char *name, int namlen, u64 ino)
{
        struct svc_export       *exp;
        struct dentry           *dparent, *dchild;
        __be32 rv = nfserr_noent;

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

        if (isdotent(name, namlen)) {

                if (namlen == 2) {
                        dchild = dget_parent(dparent);
                        /*
                         * Don't return filehandle for ".." if we're at
                         * the filesystem or export root:
                         */
                        if (dchild == dparent)
                                goto out;
                        if (dparent == exp->ex_path.dentry)
                                goto out;
                } else
                        dchild = dget(dparent);
        } else
                dchild = lookup_positive_unlocked(name, dparent, namlen);
        if (IS_ERR(dchild))
                return rv;
        if (d_mountpoint(dchild))
                goto out;
        if (dchild->d_inode->i_ino != ino)
                goto out;
        rv = fh_compose(fhp, exp, dchild, &cd->fh);
out:
        dput(dchild);
        return rv;
}

/**
 * nfs3svc_encode_cookie3 - Encode a directory offset cookie
 * @resp: readdir result context
 * @offset: offset cookie to encode
 *
 * The buffer space for the offset cookie has already been reserved
 * by svcxdr_encode_entry3_common().
 */
void nfs3svc_encode_cookie3(struct nfsd3_readdirres *resp, u64 offset)
{
        __be64 cookie = cpu_to_be64(offset);

        if (!resp->cookie_offset)
                return;
        write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie,
                               sizeof(cookie));
        resp->cookie_offset = 0;
}

static bool
svcxdr_encode_entry3_common(struct nfsd3_readdirres *resp, const char *name,
                            int namlen, loff_t offset, u64 ino)
{
        struct xdr_buf *dirlist = &resp->dirlist;
        struct xdr_stream *xdr = &resp->xdr;

        if (xdr_stream_encode_item_present(xdr) < 0)
                return false;
        /* fileid */
        if (xdr_stream_encode_u64(xdr, ino) < 0)
                return false;
        /* name */
        if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS3_MAXNAMLEN)) < 0)
                return false;
        /* cookie */
        resp->cookie_offset = dirlist->len;
        if (xdr_stream_encode_u64(xdr, OFFSET_MAX) < 0)
                return false;

        return true;
}

/**
 * nfs3svc_encode_entry3 - encode one NFSv3 READDIR entry
 * @data: directory context
 * @name: name of the object to be encoded
 * @namlen: length of that name, in bytes
 * @offset: the offset of the previous entry
 * @ino: the fileid of this entry
 * @d_type: unused
 *
 * Return values:
 *   %0: Entry was successfully encoded.
 *   %-EINVAL: An encoding problem occured, secondary status code in resp->common.err
 *
 * On exit, the following fields are updated:
 *   - resp->xdr
 *   - resp->common.err
 *   - resp->cookie_offset
 */
int nfs3svc_encode_entry3(void *data, const char *name, int namlen,
                          loff_t offset, u64 ino, unsigned int d_type)
{
        struct readdir_cd *ccd = data;
        struct nfsd3_readdirres *resp = container_of(ccd,
                                                     struct nfsd3_readdirres,
                                                     common);
        unsigned int starting_length = resp->dirlist.len;

        /* The offset cookie for the previous entry */
        nfs3svc_encode_cookie3(resp, offset);

        if (!svcxdr_encode_entry3_common(resp, name, namlen, offset, ino))
                goto out_toosmall;

        xdr_commit_encode(&resp->xdr);
        resp->common.err = nfs_ok;
        return 0;

out_toosmall:
        resp->cookie_offset = 0;
        resp->common.err = nfserr_toosmall;
        resp->dirlist.len = starting_length;
        return -EINVAL;
}

static bool
svcxdr_encode_entry3_plus(struct nfsd3_readdirres *resp, const char *name,
                          int namlen, u64 ino)
{
        struct xdr_stream *xdr = &resp->xdr;
        struct svc_fh *fhp = &resp->scratch;
        bool result;

        result = false;
        fh_init(fhp, NFS3_FHSIZE);
        if (compose_entry_fh(resp, fhp, name, namlen, ino) != nfs_ok)
                goto out_noattrs;

        if (!svcxdr_encode_post_op_attr(resp->rqstp, xdr, fhp))
                goto out;
        if (!svcxdr_encode_post_op_fh3(xdr, fhp))
                goto out;
        result = true;

out:
        fh_put(fhp);
        return result;

out_noattrs:
        if (xdr_stream_encode_item_absent(xdr) < 0)
                return false;
        if (xdr_stream_encode_item_absent(xdr) < 0)
                return false;
        return true;
}

/**
 * nfs3svc_encode_entryplus3 - encode one NFSv3 READDIRPLUS entry
 * @data: directory context
 * @name: name of the object to be encoded
 * @namlen: length of that name, in bytes
 * @offset: the offset of the previous entry
 * @ino: the fileid of this entry
 * @d_type: unused
 *
 * Return values:
 *   %0: Entry was successfully encoded.
 *   %-EINVAL: An encoding problem occured, secondary status code in resp->common.err
 *
 * On exit, the following fields are updated:
 *   - resp->xdr
 *   - resp->common.err
 *   - resp->cookie_offset
 */
int nfs3svc_encode_entryplus3(void *data, const char *name, int namlen,
                              loff_t offset, u64 ino, unsigned int d_type)
{
        struct readdir_cd *ccd = data;
        struct nfsd3_readdirres *resp = container_of(ccd,
                                                     struct nfsd3_readdirres,
                                                     common);
        unsigned int starting_length = resp->dirlist.len;

        /* The offset cookie for the previous entry */
        nfs3svc_encode_cookie3(resp, offset);

        if (!svcxdr_encode_entry3_common(resp, name, namlen, offset, ino))
                goto out_toosmall;
        if (!svcxdr_encode_entry3_plus(resp, name, namlen, ino))
                goto out_toosmall;

        xdr_commit_encode(&resp->xdr);
        resp->common.err = nfs_ok;
        return 0;

out_toosmall:
        resp->cookie_offset = 0;
        resp->common.err = nfserr_toosmall;
        resp->dirlist.len = starting_length;
        return -EINVAL;
}

static bool
svcxdr_encode_fsstat3resok(struct xdr_stream *xdr,
                           const struct nfsd3_fsstatres *resp)
{
        const struct kstatfs *s = &resp->stats;
        u64 bs = s->f_bsize;
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 13);
        if (!p)
                return false;
        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 = cpu_to_be32(resp->invarsec);               /* mean unchanged time */

        return true;
}

/* FSSTAT */
bool
nfs3svc_encode_fsstatres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_fsstatres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
                if (!svcxdr_encode_fsstat3resok(xdr, resp))
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
        }

        return true;
}

static bool
svcxdr_encode_fsinfo3resok(struct xdr_stream *xdr,
                           const struct nfsd3_fsinfores *resp)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 12);
        if (!p)
                return false;
        *p++ = cpu_to_be32(resp->f_rtmax);
        *p++ = cpu_to_be32(resp->f_rtpref);
        *p++ = cpu_to_be32(resp->f_rtmult);
        *p++ = cpu_to_be32(resp->f_wtmax);
        *p++ = cpu_to_be32(resp->f_wtpref);
        *p++ = cpu_to_be32(resp->f_wtmult);
        *p++ = cpu_to_be32(resp->f_dtpref);
        p = xdr_encode_hyper(p, resp->f_maxfilesize);
        p = encode_nfstime3(p, &nfs3svc_time_delta);
        *p = cpu_to_be32(resp->f_properties);

        return true;
}

/* FSINFO */
bool
nfs3svc_encode_fsinfores(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_fsinfores *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
                if (!svcxdr_encode_fsinfo3resok(xdr, resp))
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
        }

        return true;
}

static bool
svcxdr_encode_pathconf3resok(struct xdr_stream *xdr,
                             const struct nfsd3_pathconfres *resp)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, XDR_UNIT * 6);
        if (!p)
                return false;
        *p++ = cpu_to_be32(resp->p_link_max);
        *p++ = cpu_to_be32(resp->p_name_max);
        p = xdr_encode_bool(p, resp->p_no_trunc);
        p = xdr_encode_bool(p, resp->p_chown_restricted);
        p = xdr_encode_bool(p, resp->p_case_insensitive);
        xdr_encode_bool(p, resp->p_case_preserving);

        return true;
}

/* PATHCONF */
bool
nfs3svc_encode_pathconfres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_pathconfres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
                if (!svcxdr_encode_pathconf3resok(xdr, resp))
                        return false;
                break;
        default:
                if (!svcxdr_encode_post_op_attr(rqstp, xdr, &nfs3svc_null_fh))
                        return false;
        }

        return true;
}

/* COMMIT */
bool
nfs3svc_encode_commitres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
        struct nfsd3_commitres *resp = rqstp->rq_resp;

        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return false;
        switch (resp->status) {
        case nfs_ok:
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh))
                        return false;
                if (!svcxdr_encode_writeverf3(xdr, resp->verf))
                        return false;
                break;
        default:
                if (!svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh))
                        return false;
        }

        return true;
}

/*
 * XDR release functions
 */
void
nfs3svc_release_fhandle(struct svc_rqst *rqstp)
{
        struct nfsd3_attrstat *resp = rqstp->rq_resp;

        fh_put(&resp->fh);
}

void
nfs3svc_release_fhandle2(struct svc_rqst *rqstp)
{
        struct nfsd3_fhandle_pair *resp = rqstp->rq_resp;

        fh_put(&resp->fh1);
        fh_put(&resp->fh2);
}