NFS: Introduce new-style XDR decoding functions for NFSv2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / nfs / nfs3xdr.c

/*
 * linux/fs/nfs/nfs3xdr.c
 *
 * XDR functions to encode/decode NFSv3 RPC arguments and results.
 *
 * Copyright (C) 1996, 1997 Olaf Kirch
 */

#include <linux/param.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
#include <linux/kdev_t.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs3.h>
#include <linux/nfs_fs.h>
#include <linux/nfsacl.h>
#include "internal.h"

#define NFSDBG_FACILITY         NFSDBG_XDR

/* Mapping from NFS error code to "errno" error code. */
#define errno_NFSERR_IO         EIO

/*
 * Declare the space requirements for NFS arguments and replies as
 * number of 32bit-words
 */
#define NFS3_fhandle_sz         (1+16)
#define NFS3_fh_sz              (NFS3_fhandle_sz)       /* shorthand */
#define NFS3_sattr_sz           (15)
#define NFS3_filename_sz        (1+(NFS3_MAXNAMLEN>>2))
#define NFS3_path_sz            (1+(NFS3_MAXPATHLEN>>2))
#define NFS3_fattr_sz           (21)
#define NFS3_cookieverf_sz      (NFS3_COOKIEVERFSIZE>>2)
#define NFS3_wcc_attr_sz                (6)
#define NFS3_pre_op_attr_sz     (1+NFS3_wcc_attr_sz)
#define NFS3_post_op_attr_sz    (1+NFS3_fattr_sz)
#define NFS3_wcc_data_sz                (NFS3_pre_op_attr_sz+NFS3_post_op_attr_sz)
#define NFS3_fsstat_sz          
#define NFS3_fsinfo_sz          
#define NFS3_pathconf_sz                
#define NFS3_entry_sz           (NFS3_filename_sz+3)
#define NFS3_diropargs_sz       (NFS3_fh_sz+NFS3_filename_sz)

#define NFS3_getattrargs_sz     (NFS3_fh_sz)
#define NFS3_setattrargs_sz     (NFS3_fh_sz+NFS3_sattr_sz+3)
#define NFS3_lookupargs_sz      (NFS3_fh_sz+NFS3_filename_sz)
#define NFS3_accessargs_sz      (NFS3_fh_sz+1)
#define NFS3_readlinkargs_sz    (NFS3_fh_sz)
#define NFS3_readargs_sz        (NFS3_fh_sz+3)
#define NFS3_writeargs_sz       (NFS3_fh_sz+5)
#define NFS3_createargs_sz      (NFS3_diropargs_sz+NFS3_sattr_sz)
#define NFS3_mkdirargs_sz       (NFS3_diropargs_sz+NFS3_sattr_sz)
#define NFS3_symlinkargs_sz     (NFS3_diropargs_sz+1+NFS3_sattr_sz)
#define NFS3_mknodargs_sz       (NFS3_diropargs_sz+2+NFS3_sattr_sz)
#define NFS3_removeargs_sz      (NFS3_fh_sz+NFS3_filename_sz)
#define NFS3_renameargs_sz      (NFS3_diropargs_sz+NFS3_diropargs_sz)
#define NFS3_linkargs_sz                (NFS3_fh_sz+NFS3_diropargs_sz)
#define NFS3_readdirargs_sz     (NFS3_fh_sz+NFS3_cookieverf_sz+3)
#define NFS3_readdirplusargs_sz (NFS3_fh_sz+NFS3_cookieverf_sz+4)
#define NFS3_commitargs_sz      (NFS3_fh_sz+3)

#define NFS3_attrstat_sz        (1+NFS3_fattr_sz)
#define NFS3_wccstat_sz         (1+NFS3_wcc_data_sz)
#define NFS3_removeres_sz       (NFS3_wccstat_sz)
#define NFS3_lookupres_sz       (1+NFS3_fh_sz+(2 * NFS3_post_op_attr_sz))
#define NFS3_accessres_sz       (1+NFS3_post_op_attr_sz+1)
#define NFS3_readlinkres_sz     (1+NFS3_post_op_attr_sz+1)
#define NFS3_readres_sz         (1+NFS3_post_op_attr_sz+3)
#define NFS3_writeres_sz        (1+NFS3_wcc_data_sz+4)
#define NFS3_createres_sz       (1+NFS3_fh_sz+NFS3_post_op_attr_sz+NFS3_wcc_data_sz)
#define NFS3_renameres_sz       (1+(2 * NFS3_wcc_data_sz))
#define NFS3_linkres_sz         (1+NFS3_post_op_attr_sz+NFS3_wcc_data_sz)
#define NFS3_readdirres_sz      (1+NFS3_post_op_attr_sz+2)
#define NFS3_fsstatres_sz       (1+NFS3_post_op_attr_sz+13)
#define NFS3_fsinfores_sz       (1+NFS3_post_op_attr_sz+12)
#define NFS3_pathconfres_sz     (1+NFS3_post_op_attr_sz+6)
#define NFS3_commitres_sz       (1+NFS3_wcc_data_sz+2)

#define ACL3_getaclargs_sz      (NFS3_fh_sz+1)
#define ACL3_setaclargs_sz      (NFS3_fh_sz+1+ \
                                XDR_QUADLEN(NFS_ACL_INLINE_BUFSIZE))
#define ACL3_getaclres_sz       (1+NFS3_post_op_attr_sz+1+ \
                                XDR_QUADLEN(NFS_ACL_INLINE_BUFSIZE))
#define ACL3_setaclres_sz       (1+NFS3_post_op_attr_sz)

/*
 * Map file type to S_IFMT bits
 */
static const umode_t nfs_type2fmt[] = {
        [NF3BAD] = 0,
        [NF3REG] = S_IFREG,
        [NF3DIR] = S_IFDIR,
        [NF3BLK] = S_IFBLK,
        [NF3CHR] = S_IFCHR,
        [NF3LNK] = S_IFLNK,
        [NF3SOCK] = S_IFSOCK,
        [NF3FIFO] = S_IFIFO,
};

/*
 * While encoding arguments, set up the reply buffer in advance to
 * receive reply data directly into the page cache.
 */
static void prepare_reply_buffer(struct rpc_rqst *req, struct page **pages,
                                 unsigned int base, unsigned int len,
                                 unsigned int bufsize)
{
        struct rpc_auth *auth = req->rq_cred->cr_auth;
        unsigned int replen;

        replen = RPC_REPHDRSIZE + auth->au_rslack + bufsize;
        xdr_inline_pages(&req->rq_rcv_buf, replen << 2, pages, base, len);
}

/*
 * Handle decode buffer overflows out-of-line.
 */
static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
{
        dprintk("NFS: %s prematurely hit the end of our receive buffer. "
                "Remaining buffer length is %tu words.\n",
                func, xdr->end - xdr->p);
}


/*
 * Common NFS XDR functions as inlines
 */
static inline __be32 *
xdr_decode_fhandle(__be32 *p, struct nfs_fh *fh)
{
        if ((fh->size = ntohl(*p++)) <= NFS3_FHSIZE) {
                memcpy(fh->data, p, fh->size);
                return p + XDR_QUADLEN(fh->size);
        }
        return NULL;
}

static inline __be32 *
xdr_decode_fhandle_stream(struct xdr_stream *xdr, struct nfs_fh *fh)
{
        __be32 *p;
        p = xdr_inline_decode(xdr, 4);
        if (unlikely(!p))
                goto out_overflow;
        fh->size = ntohl(*p++);

        if (fh->size <= NFS3_FHSIZE) {
                p = xdr_inline_decode(xdr, fh->size);
                if (unlikely(!p))
                        goto out_overflow;
                memcpy(fh->data, p, fh->size);
                return p + XDR_QUADLEN(fh->size);
        }
        return NULL;

out_overflow:
        print_overflow_msg(__func__, xdr);
        return ERR_PTR(-EIO);
}

/*
 * Encode/decode time.
 */
static inline __be32 *
xdr_decode_time3(__be32 *p, struct timespec *timep)
{
        timep->tv_sec = ntohl(*p++);
        timep->tv_nsec = ntohl(*p++);
        return p;
}

static __be32 *
xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr)
{
        unsigned int    type, major, minor;
        umode_t         fmode;

        type = ntohl(*p++);
        if (type > NF3FIFO)
                type = NF3NON;
        fmode = nfs_type2fmt[type];
        fattr->mode = (ntohl(*p++) & ~S_IFMT) | fmode;
        fattr->nlink = ntohl(*p++);
        fattr->uid = ntohl(*p++);
        fattr->gid = ntohl(*p++);
        p = xdr_decode_hyper(p, &fattr->size);
        p = xdr_decode_hyper(p, &fattr->du.nfs3.used);

        /* Turn remote device info into Linux-specific dev_t */
        major = ntohl(*p++);
        minor = ntohl(*p++);
        fattr->rdev = MKDEV(major, minor);
        if (MAJOR(fattr->rdev) != major || MINOR(fattr->rdev) != minor)
                fattr->rdev = 0;

        p = xdr_decode_hyper(p, &fattr->fsid.major);
        fattr->fsid.minor = 0;
        p = xdr_decode_hyper(p, &fattr->fileid);
        p = xdr_decode_time3(p, &fattr->atime);
        p = xdr_decode_time3(p, &fattr->mtime);
        p = xdr_decode_time3(p, &fattr->ctime);

        /* Update the mode bits */
        fattr->valid |= NFS_ATTR_FATTR_V3;
        return p;
}

static inline __be32 *
xdr_decode_wcc_attr(__be32 *p, struct nfs_fattr *fattr)
{
        p = xdr_decode_hyper(p, &fattr->pre_size);
        p = xdr_decode_time3(p, &fattr->pre_mtime);
        p = xdr_decode_time3(p, &fattr->pre_ctime);
        fattr->valid |= NFS_ATTR_FATTR_PRESIZE
                | NFS_ATTR_FATTR_PREMTIME
                | NFS_ATTR_FATTR_PRECTIME;
        return p;
}

static inline __be32 *
xdr_decode_post_op_attr(__be32 *p, struct nfs_fattr *fattr)
{
        if (*p++)
                p = xdr_decode_fattr(p, fattr);
        return p;
}

static inline __be32 *
xdr_decode_post_op_attr_stream(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(!p))
                goto out_overflow;
        if (ntohl(*p++)) {
                p = xdr_inline_decode(xdr, 84);
                if (unlikely(!p))
                        goto out_overflow;
                p = xdr_decode_fattr(p, fattr);
        }
        return p;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return ERR_PTR(-EIO);
}

static inline __be32 *
xdr_decode_pre_op_attr(__be32 *p, struct nfs_fattr *fattr)
{
        if (*p++)
                return xdr_decode_wcc_attr(p, fattr);
        return p;
}


static inline __be32 *
xdr_decode_wcc_data(__be32 *p, struct nfs_fattr *fattr)
{
        p = xdr_decode_pre_op_attr(p, fattr);
        return xdr_decode_post_op_attr(p, fattr);
}


/*
 * Encode/decode NFSv3 basic data types
 *
 * Basic NFSv3 data types are defined in section 2.5 of RFC 1813:
 * "NFS Version 3 Protocol Specification".
 *
 * Not all basic data types have their own encoding and decoding
 * functions.  For run-time efficiency, some data types are encoded
 * or decoded inline.
 */

static void encode_uint32(struct xdr_stream *xdr, u32 value)
{
        __be32 *p = xdr_reserve_space(xdr, 4);
        *p = cpu_to_be32(value);
}

static int decode_uint32(struct xdr_stream *xdr, u32 *value)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        *value = be32_to_cpup(p);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int decode_uint64(struct xdr_stream *xdr, u64 *value)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 8);
        if (unlikely(p == NULL))
                goto out_overflow;
        xdr_decode_hyper(p, value);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * fileid3
 *
 *      typedef uint64 fileid3;
 */
static int decode_fileid3(struct xdr_stream *xdr, u64 *fileid)
{
        return decode_uint64(xdr, fileid);
}

/*
 * filename3
 *
 *      typedef string filename3<>;
 */
static void encode_filename3(struct xdr_stream *xdr,
                             const char *name, u32 length)
{
        __be32 *p;

        BUG_ON(length > NFS3_MAXNAMLEN);
        p = xdr_reserve_space(xdr, 4 + length);
        xdr_encode_opaque(p, name, length);
}

static int decode_inline_filename3(struct xdr_stream *xdr,
                                   const char **name, u32 *length)
{
        __be32 *p;
        u32 count;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        count = be32_to_cpup(p);
        if (count > NFS3_MAXNAMLEN)
                goto out_nametoolong;
        p = xdr_inline_decode(xdr, count);
        if (unlikely(p == NULL))
                goto out_overflow;
        *name = (const char *)p;
        *length = count;
        return 0;

out_nametoolong:
        dprintk("NFS: returned filename too long: %u\n", count);
        return -ENAMETOOLONG;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * nfspath3
 *
 *      typedef string nfspath3<>;
 */
static void encode_nfspath3(struct xdr_stream *xdr, struct page **pages,
                            const u32 length)
{
        BUG_ON(length > NFS3_MAXPATHLEN);
        encode_uint32(xdr, length);
        xdr_write_pages(xdr, pages, 0, length);
}

static int decode_nfspath3(struct xdr_stream *xdr)
{
        u32 recvd, count;
        size_t hdrlen;
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        count = be32_to_cpup(p);
        if (unlikely(count >= xdr->buf->page_len || count > NFS3_MAXPATHLEN))
                goto out_nametoolong;
        hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base;
        recvd = xdr->buf->len - hdrlen;
        if (unlikely(count > recvd))
                goto out_cheating;

        xdr_read_pages(xdr, count);
        xdr_terminate_string(xdr->buf, count);
        return 0;

out_nametoolong:
        dprintk("NFS: returned pathname too long: %u\n", count);
        return -ENAMETOOLONG;
out_cheating:
        dprintk("NFS: server cheating in pathname result: "
                "count %u > recvd %u\n", count, recvd);
        return -EIO;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * cookie3
 *
 *      typedef uint64 cookie3
 */
static __be32 *xdr_encode_cookie3(__be32 *p, u64 cookie)
{
        return xdr_encode_hyper(p, cookie);
}

static int decode_cookie3(struct xdr_stream *xdr, u64 *cookie)
{
        return decode_uint64(xdr, cookie);
}

/*
 * cookieverf3
 *
 *      typedef opaque cookieverf3[NFS3_COOKIEVERFSIZE];
 */
static __be32 *xdr_encode_cookieverf3(__be32 *p, const __be32 *verifier)
{
        memcpy(p, verifier, NFS3_COOKIEVERFSIZE);
        return p + XDR_QUADLEN(NFS3_COOKIEVERFSIZE);
}

static int decode_cookieverf3(struct xdr_stream *xdr, __be32 *verifier)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, NFS3_COOKIEVERFSIZE);
        if (unlikely(p == NULL))
                goto out_overflow;
        memcpy(verifier, p, NFS3_COOKIEVERFSIZE);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * createverf3
 *
 *      typedef opaque createverf3[NFS3_CREATEVERFSIZE];
 */
static void encode_createverf3(struct xdr_stream *xdr, const __be32 *verifier)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, NFS3_CREATEVERFSIZE);
        memcpy(p, verifier, NFS3_CREATEVERFSIZE);
}

static int decode_writeverf3(struct xdr_stream *xdr, __be32 *verifier)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, NFS3_WRITEVERFSIZE);
        if (unlikely(p == NULL))
                goto out_overflow;
        memcpy(verifier, p, NFS3_WRITEVERFSIZE);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * size3
 *
 *      typedef uint64 size3;
 */
static __be32 *xdr_decode_size3(__be32 *p, u64 *size)
{
        return xdr_decode_hyper(p, size);
}

/*
 * nfsstat3
 *
 *      enum nfsstat3 {
 *              NFS3_OK = 0,
 *              ...
 *      }
 */
#define NFS3_OK         NFS_OK

static int decode_nfsstat3(struct xdr_stream *xdr, enum nfs_stat *status)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        *status = be32_to_cpup(p);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * ftype3
 *
 *      enum ftype3 {
 *              NF3REG  = 1,
 *              NF3DIR  = 2,
 *              NF3BLK  = 3,
 *              NF3CHR  = 4,
 *              NF3LNK  = 5,
 *              NF3SOCK = 6,
 *              NF3FIFO = 7
 *      };
 */
static void encode_ftype3(struct xdr_stream *xdr, const u32 type)
{
        BUG_ON(type > NF3FIFO);
        encode_uint32(xdr, type);
}

/*
 * specdata3
 *
 *     struct specdata3 {
 *             uint32  specdata1;
 *             uint32  specdata2;
 *     };
 */
static void encode_specdata3(struct xdr_stream *xdr, const dev_t rdev)
{
        __be32 *p;

        p = xdr_reserve_space(xdr, 8);
        *p++ = cpu_to_be32(MAJOR(rdev));
        *p = cpu_to_be32(MINOR(rdev));
}

/*
 * nfs_fh3
 *
 *      struct nfs_fh3 {
 *              opaque       data<NFS3_FHSIZE>;
 *      };
 */
static void encode_nfs_fh3(struct xdr_stream *xdr, const struct nfs_fh *fh)
{
        __be32 *p;

        BUG_ON(fh->size > NFS3_FHSIZE);
        p = xdr_reserve_space(xdr, 4 + fh->size);
        xdr_encode_opaque(p, fh->data, fh->size);
}

static int decode_nfs_fh3(struct xdr_stream *xdr, struct nfs_fh *fh)
{
        u32 length;
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        length = be32_to_cpup(p++);
        if (unlikely(length > NFS3_FHSIZE))
                goto out_toobig;
        p = xdr_inline_decode(xdr, length);
        if (unlikely(p == NULL))
                goto out_overflow;
        fh->size = length;
        memcpy(fh->data, p, length);
        return 0;
out_toobig:
        dprintk("NFS: file handle size (%u) too big\n", length);
        return -E2BIG;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static void zero_nfs_fh3(struct nfs_fh *fh)
{
        memset(fh, 0, sizeof(*fh));
}

/*
 * nfstime3
 *
 *      struct nfstime3 {
 *              uint32  seconds;
 *              uint32  nseconds;
 *      };
 */
static __be32 *xdr_encode_nfstime3(__be32 *p, const struct timespec *timep)
{
        *p++ = cpu_to_be32(timep->tv_sec);
        *p++ = cpu_to_be32(timep->tv_nsec);
        return p;
}

/*
 * sattr3
 *
 *      enum time_how {
 *              DONT_CHANGE             = 0,
 *              SET_TO_SERVER_TIME      = 1,
 *              SET_TO_CLIENT_TIME      = 2
 *      };
 *
 *      union set_mode3 switch (bool set_it) {
 *      case TRUE:
 *              mode3   mode;
 *      default:
 *              void;
 *      };
 *
 *      union set_uid3 switch (bool set_it) {
 *      case TRUE:
 *              uid3    uid;
 *      default:
 *              void;
 *      };
 *
 *      union set_gid3 switch (bool set_it) {
 *      case TRUE:
 *              gid3    gid;
 *      default:
 *              void;
 *      };
 *
 *      union set_size3 switch (bool set_it) {
 *      case TRUE:
 *              size3   size;
 *      default:
 *              void;
 *      };
 *
 *      union set_atime switch (time_how set_it) {
 *      case SET_TO_CLIENT_TIME:
 *              nfstime3        atime;
 *      default:
 *              void;
 *      };
 *
 *      union set_mtime switch (time_how set_it) {
 *      case SET_TO_CLIENT_TIME:
 *              nfstime3  mtime;
 *      default:
 *              void;
 *      };
 *
 *      struct sattr3 {
 *              set_mode3       mode;
 *              set_uid3        uid;
 *              set_gid3        gid;
 *              set_size3       size;
 *              set_atime       atime;
 *              set_mtime       mtime;
 *      };
 */
static void encode_sattr3(struct xdr_stream *xdr, const struct iattr *attr)
{
        u32 nbytes;
        __be32 *p;

        /*
         * In order to make only a single xdr_reserve_space() call,
         * pre-compute the total number of bytes to be reserved.
         * Six boolean values, one for each set_foo field, are always
         * present in the encoded result, so start there.
         */
        nbytes = 6 * 4;
        if (attr->ia_valid & ATTR_MODE)
                nbytes += 4;
        if (attr->ia_valid & ATTR_UID)
                nbytes += 4;
        if (attr->ia_valid & ATTR_GID)
                nbytes += 4;
        if (attr->ia_valid & ATTR_SIZE)
                nbytes += 8;
        if (attr->ia_valid & ATTR_ATIME_SET)
                nbytes += 8;
        if (attr->ia_valid & ATTR_MTIME_SET)
                nbytes += 8;
        p = xdr_reserve_space(xdr, nbytes);

        if (attr->ia_valid & ATTR_MODE) {
                *p++ = xdr_one;
                *p++ = cpu_to_be32(attr->ia_mode & S_IALLUGO);
        } else
                *p++ = xdr_zero;

        if (attr->ia_valid & ATTR_UID) {
                *p++ = xdr_one;
                *p++ = cpu_to_be32(attr->ia_uid);
        } else
                *p++ = xdr_zero;

        if (attr->ia_valid & ATTR_GID) {
                *p++ = xdr_one;
                *p++ = cpu_to_be32(attr->ia_gid);
        } else
                *p++ = xdr_zero;

        if (attr->ia_valid & ATTR_SIZE) {
                *p++ = xdr_one;
                p = xdr_encode_hyper(p, (u64)attr->ia_size);
        } else
                *p++ = xdr_zero;

        if (attr->ia_valid & ATTR_ATIME_SET) {
                *p++ = xdr_two;
                p = xdr_encode_nfstime3(p, &attr->ia_atime);
        } else if (attr->ia_valid & ATTR_ATIME) {
                *p++ = xdr_one;
        } else
                *p++ = xdr_zero;

        if (attr->ia_valid & ATTR_MTIME_SET) {
                *p++ = xdr_two;
                xdr_encode_nfstime3(p, &attr->ia_mtime);
        } else if (attr->ia_valid & ATTR_MTIME) {
                *p = xdr_one;
        } else
                *p = xdr_zero;
}

/*
 * fattr3
 *
 *      struct fattr3 {
 *              ftype3          type;
 *              mode3           mode;
 *              uint32          nlink;
 *              uid3            uid;
 *              gid3            gid;
 *              size3           size;
 *              size3           used;
 *              specdata3       rdev;
 *              uint64          fsid;
 *              fileid3         fileid;
 *              nfstime3        atime;
 *              nfstime3        mtime;
 *              nfstime3        ctime;
 *      };
 */
static int decode_fattr3(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, NFS3_fattr_sz << 2);
        if (unlikely(p == NULL))
                goto out_overflow;
        xdr_decode_fattr(p, fattr);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * post_op_attr
 *
 *      union post_op_attr switch (bool attributes_follow) {
 *      case TRUE:
 *              fattr3  attributes;
 *      case FALSE:
 *              void;
 *      };
 */
static int decode_post_op_attr(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        if (*p != xdr_zero)
                return decode_fattr3(xdr, fattr);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * wcc_attr
 *      struct wcc_attr {
 *              size3           size;
 *              nfstime3        mtime;
 *              nfstime3        ctime;
 *      };
 */
static int decode_wcc_attr(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, NFS3_wcc_attr_sz << 2);
        if (unlikely(p == NULL))
                goto out_overflow;
        xdr_decode_wcc_attr(p, fattr);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * pre_op_attr
 *      union pre_op_attr switch (bool attributes_follow) {
 *      case TRUE:
 *              wcc_attr        attributes;
 *      case FALSE:
 *              void;
 *      };
 *
 * wcc_data
 *
 *      struct wcc_data {
 *              pre_op_attr     before;
 *              post_op_attr    after;
 *      };
 */
static int decode_pre_op_attr(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        if (*p != xdr_zero)
                return decode_wcc_attr(xdr, fattr);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int decode_wcc_data(struct xdr_stream *xdr, struct nfs_fattr *fattr)
{
        int error;

        error = decode_pre_op_attr(xdr, fattr);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(xdr, fattr);
out:
        return error;
}

/*
 * post_op_fh3
 *
 *      union post_op_fh3 switch (bool handle_follows) {
 *      case TRUE:
 *              nfs_fh3  handle;
 *      case FALSE:
 *              void;
 *      };
 */
static int decode_post_op_fh3(struct xdr_stream *xdr, struct nfs_fh *fh)
{
        __be32 *p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        if (*p != xdr_zero)
                return decode_nfs_fh3(xdr, fh);
        zero_nfs_fh3(fh);
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

/*
 * diropargs3
 *
 *      struct diropargs3 {
 *              nfs_fh3         dir;
 *              filename3       name;
 *      };
 */
static void encode_diropargs3(struct xdr_stream *xdr, const struct nfs_fh *fh,
                              const char *name, u32 length)
{
        encode_nfs_fh3(xdr, fh);
        encode_filename3(xdr, name, length);
}


/*
 * NFSv3 XDR encode functions
 *
 * NFSv3 argument types are defined in section 3.3 of RFC 1813:
 * "NFS Version 3 Protocol Specification".
 */

/*
 * 3.3.1  GETATTR3args
 *
 *      struct GETATTR3args {
 *              nfs_fh3  object;
 *      };
 */
static int nfs3_xdr_enc_getattr3args(struct rpc_rqst *req, __be32 *p,
                                     const struct nfs_fh *fh)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, fh);
        return 0;
}

/*
 * 3.3.2  SETATTR3args
 *
 *      union sattrguard3 switch (bool check) {
 *      case TRUE:
 *              nfstime3  obj_ctime;
 *      case FALSE:
 *              void;
 *      };
 *
 *      struct SETATTR3args {
 *              nfs_fh3         object;
 *              sattr3          new_attributes;
 *              sattrguard3     guard;
 *      };
 */
static void encode_sattrguard3(struct xdr_stream *xdr,
                               const struct nfs3_sattrargs *args)
{
        __be32 *p;

        if (args->guard) {
                p = xdr_reserve_space(xdr, 4 + 8);
                *p++ = xdr_one;
                xdr_encode_nfstime3(p, &args->guardtime);
        } else {
                p = xdr_reserve_space(xdr, 4);
                *p = xdr_zero;
        }
}

static int nfs3_xdr_enc_setattr3args(struct rpc_rqst *req, __be32 *p,
                                     const struct nfs3_sattrargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, args->fh);
        encode_sattr3(&xdr, args->sattr);
        encode_sattrguard3(&xdr, args);
        return 0;
}

/*
 * 3.3.3  LOOKUP3args
 *
 *      struct LOOKUP3args {
 *              diropargs3  what;
 *      };
 */
static int nfs3_xdr_enc_lookup3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs3_diropargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fh, args->name, args->len);
        return 0;
}

/*
 * 3.3.4  ACCESS3args
 *
 *      struct ACCESS3args {
 *              nfs_fh3         object;
 *              uint32          access;
 *      };
 */
static void encode_access3args(struct xdr_stream *xdr,
                               const struct nfs3_accessargs *args)
{
        encode_nfs_fh3(xdr, args->fh);
        encode_uint32(xdr, args->access);
}

static int nfs3_xdr_enc_access3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs3_accessargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_access3args(&xdr, args);
        return 0;
}

/*
 * 3.3.5  READLINK3args
 *
 *      struct READLINK3args {
 *              nfs_fh3 symlink;
 *      };
 */
static int nfs3_xdr_enc_readlink3args(struct rpc_rqst *req, __be32 *p,
                                      const struct nfs3_readlinkargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, args->fh);
        prepare_reply_buffer(req, args->pages, args->pgbase,
                                        args->pglen, NFS3_readlinkres_sz);
        return 0;
}

/*
 * 3.3.6  READ3args
 *
 *      struct READ3args {
 *              nfs_fh3         file;
 *              offset3         offset;
 *              count3          count;
 *      };
 */
static void encode_read3args(struct xdr_stream *xdr,
                             const struct nfs_readargs *args)
{
        __be32 *p;

        encode_nfs_fh3(xdr, args->fh);

        p = xdr_reserve_space(xdr, 8 + 4);
        p = xdr_encode_hyper(p, args->offset);
        *p = cpu_to_be32(args->count);
}

static int nfs3_xdr_enc_read3args(struct rpc_rqst *req, __be32 *p,
                                  const struct nfs_readargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_read3args(&xdr, args);
        prepare_reply_buffer(req, args->pages, args->pgbase,
                                        args->count, NFS3_readres_sz);
        req->rq_rcv_buf.flags |= XDRBUF_READ;
        return 0;
}

/*
 * 3.3.7  WRITE3args
 *
 *      enum stable_how {
 *              UNSTABLE  = 0,
 *              DATA_SYNC = 1,
 *              FILE_SYNC = 2
 *      };
 *
 *      struct WRITE3args {
 *              nfs_fh3         file;
 *              offset3         offset;
 *              count3          count;
 *              stable_how      stable;
 *              opaque          data<>;
 *      };
 */
static void encode_write3args(struct xdr_stream *xdr,
                              const struct nfs_writeargs *args)
{
        __be32 *p;

        encode_nfs_fh3(xdr, args->fh);

        p = xdr_reserve_space(xdr, 8 + 4 + 4 + 4);
        p = xdr_encode_hyper(p, args->offset);
        *p++ = cpu_to_be32(args->count);

        BUG_ON(args->stable > NFS_FILE_SYNC);
        *p++ = cpu_to_be32(args->stable);

        *p = cpu_to_be32(args->count);
        xdr_write_pages(xdr, args->pages, args->pgbase, args->count);
}

static int nfs3_xdr_enc_write3args(struct rpc_rqst *req, __be32 *p,
                                   const struct nfs_writeargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_write3args(&xdr, args);
        xdr.buf->flags |= XDRBUF_WRITE;
        return 0;
}

/*
 * 3.3.8  CREATE3args
 *
 *      enum createmode3 {
 *              UNCHECKED = 0,
 *              GUARDED   = 1,
 *              EXCLUSIVE = 2
 *      };
 *
 *      union createhow3 switch (createmode3 mode) {
 *      case UNCHECKED:
 *      case GUARDED:
 *              sattr3       obj_attributes;
 *      case EXCLUSIVE:
 *              createverf3  verf;
 *      };
 *
 *      struct CREATE3args {
 *              diropargs3      where;
 *              createhow3      how;
 *      };
 */
static void encode_createhow3(struct xdr_stream *xdr,
                              const struct nfs3_createargs *args)
{
        encode_uint32(xdr, args->createmode);
        switch (args->createmode) {
        case NFS3_CREATE_UNCHECKED:
        case NFS3_CREATE_GUARDED:
                encode_sattr3(xdr, args->sattr);
                break;
        case NFS3_CREATE_EXCLUSIVE:
                encode_createverf3(xdr, args->verifier);
                break;
        default:
                BUG();
        }
}

static int nfs3_xdr_enc_create3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs3_createargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fh, args->name, args->len);
        encode_createhow3(&xdr, args);
        return 0;
}

/*
 * 3.3.9  MKDIR3args
 *
 *      struct MKDIR3args {
 *              diropargs3      where;
 *              sattr3          attributes;
 *      };
 */
static int nfs3_xdr_enc_mkdir3args(struct rpc_rqst *req, __be32 *p,
                                   const struct nfs3_mkdirargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fh, args->name, args->len);
        encode_sattr3(&xdr, args->sattr);
        return 0;
}

/*
 * 3.3.10  SYMLINK3args
 *
 *      struct symlinkdata3 {
 *              sattr3          symlink_attributes;
 *              nfspath3        symlink_data;
 *      };
 *
 *      struct SYMLINK3args {
 *              diropargs3      where;
 *              symlinkdata3    symlink;
 *      };
 */
static void encode_symlinkdata3(struct xdr_stream *xdr,
                                const struct nfs3_symlinkargs *args)
{
        encode_sattr3(xdr, args->sattr);
        encode_nfspath3(xdr, args->pages, args->pathlen);
}

static int nfs3_xdr_enc_symlink3args(struct rpc_rqst *req, __be32 *p,
                                     const struct nfs3_symlinkargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fromfh, args->fromname, args->fromlen);
        encode_symlinkdata3(&xdr, args);
        return 0;
}

/*
 * 3.3.11  MKNOD3args
 *
 *      struct devicedata3 {
 *              sattr3          dev_attributes;
 *              specdata3       spec;
 *      };
 *
 *      union mknoddata3 switch (ftype3 type) {
 *      case NF3CHR:
 *      case NF3BLK:
 *              devicedata3     device;
 *      case NF3SOCK:
 *      case NF3FIFO:
 *              sattr3          pipe_attributes;
 *      default:
 *              void;
 *      };
 *
 *      struct MKNOD3args {
 *              diropargs3      where;
 *              mknoddata3      what;
 *      };
 */
static void encode_devicedata3(struct xdr_stream *xdr,
                               const struct nfs3_mknodargs *args)
{
        encode_sattr3(xdr, args->sattr);
        encode_specdata3(xdr, args->rdev);
}

static void encode_mknoddata3(struct xdr_stream *xdr,
                              const struct nfs3_mknodargs *args)
{
        encode_ftype3(xdr, args->type);
        switch (args->type) {
        case NF3CHR:
        case NF3BLK:
                encode_devicedata3(xdr, args);
                break;
        case NF3SOCK:
        case NF3FIFO:
                encode_sattr3(xdr, args->sattr);
                break;
        case NF3REG:
        case NF3DIR:
                break;
        default:
                BUG();
        }
}

static int nfs3_xdr_enc_mknod3args(struct rpc_rqst *req, __be32 *p,
                                   const struct nfs3_mknodargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fh, args->name, args->len);
        encode_mknoddata3(&xdr, args);
        return 0;
}

/*
 * 3.3.12  REMOVE3args
 *
 *      struct REMOVE3args {
 *              diropargs3  object;
 *      };
 */
static int nfs3_xdr_enc_remove3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs_removeargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->fh, args->name.name, args->name.len);
        return 0;
}

/*
 * 3.3.14  RENAME3args
 *
 *      struct RENAME3args {
 *              diropargs3      from;
 *              diropargs3      to;
 *      };
 */
static int nfs3_xdr_enc_rename3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs_renameargs *args)
{
        const struct qstr *old = args->old_name;
        const struct qstr *new = args->new_name;
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_diropargs3(&xdr, args->old_dir, old->name, old->len);
        encode_diropargs3(&xdr, args->new_dir, new->name, new->len);
        return 0;
}

/*
 * 3.3.15  LINK3args
 *
 *      struct LINK3args {
 *              nfs_fh3         file;
 *              diropargs3      link;
 *      };
 */
static int nfs3_xdr_enc_link3args(struct rpc_rqst *req, __be32 *p,
                                  const struct nfs3_linkargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, args->fromfh);
        encode_diropargs3(&xdr, args->tofh, args->toname, args->tolen);
        return 0;
}

/*
 * 3.3.16  READDIR3args
 *
 *      struct READDIR3args {
 *              nfs_fh3         dir;
 *              cookie3         cookie;
 *              cookieverf3     cookieverf;
 *              count3          count;
 *      };
 */
static void encode_readdir3args(struct xdr_stream *xdr,
                                const struct nfs3_readdirargs *args)
{
        __be32 *p;

        encode_nfs_fh3(xdr, args->fh);

        p = xdr_reserve_space(xdr, 8 + NFS3_COOKIEVERFSIZE + 4);
        p = xdr_encode_cookie3(p, args->cookie);
        p = xdr_encode_cookieverf3(p, args->verf);
        *p = cpu_to_be32(args->count);
}

static int nfs3_xdr_enc_readdir3args(struct rpc_rqst *req, __be32 *p,
                                     const struct nfs3_readdirargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_readdir3args(&xdr, args);
        prepare_reply_buffer(req, args->pages, 0,
                                args->count, NFS3_readdirres_sz);
        return 0;
}

/*
 * 3.3.17  READDIRPLUS3args
 *
 *      struct READDIRPLUS3args {
 *              nfs_fh3         dir;
 *              cookie3         cookie;
 *              cookieverf3     cookieverf;
 *              count3          dircount;
 *              count3          maxcount;
 *      };
 */
static void encode_readdirplus3args(struct xdr_stream *xdr,
                                    const struct nfs3_readdirargs *args)
{
        __be32 *p;

        encode_nfs_fh3(xdr, args->fh);

        p = xdr_reserve_space(xdr, 8 + NFS3_COOKIEVERFSIZE + 4 + 4);
        p = xdr_encode_cookie3(p, args->cookie);
        p = xdr_encode_cookieverf3(p, args->verf);

        /*
         * readdirplus: need dircount + buffer size.
         * We just make sure we make dircount big enough
         */
        *p++ = cpu_to_be32(args->count >> 3);

        *p = cpu_to_be32(args->count);
}

static int nfs3_xdr_enc_readdirplus3args(struct rpc_rqst *req, __be32 *p,
                                         const struct nfs3_readdirargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_readdirplus3args(&xdr, args);
        prepare_reply_buffer(req, args->pages, 0,
                                args->count, NFS3_readdirres_sz);
        return 0;
}

/*
 * Decode the result of a readdir call.
 * We just check for syntactical correctness.
 */
static int
nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res)
{
        struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
        struct kvec *iov = rcvbuf->head;
        struct page **page;
        size_t hdrlen;
        u32 recvd, pglen;
        int status;

        status = ntohl(*p++);
        /* Decode post_op_attrs */
        p = xdr_decode_post_op_attr(p, res->dir_attr);
        if (status)
                return nfs_stat_to_errno(status);
        /* Decode verifier cookie */
        if (res->verf) {
                res->verf[0] = *p++;
                res->verf[1] = *p++;
        } else {
                p += 2;
        }

        hdrlen = (u8 *) p - (u8 *) iov->iov_base;
        if (iov->iov_len < hdrlen) {
                dprintk("NFS: READDIR reply header overflowed:"
                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                return -errno_NFSERR_IO;
        } else if (iov->iov_len != hdrlen) {
                dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
                xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
        }

        pglen = rcvbuf->page_len;
        recvd = rcvbuf->len - hdrlen;
        if (pglen > recvd)
                pglen = recvd;
        page = rcvbuf->pages;

        return pglen;
}

/*
 * 3.3.21  COMMIT3args
 *
 *      struct COMMIT3args {
 *              nfs_fh3         file;
 *              offset3         offset;
 *              count3          count;
 *      };
 */
static void encode_commit3args(struct xdr_stream *xdr,
                               const struct nfs_writeargs *args)
{
        __be32 *p;

        encode_nfs_fh3(xdr, args->fh);

        p = xdr_reserve_space(xdr, 8 + 4);
        p = xdr_encode_hyper(p, args->offset);
        *p = cpu_to_be32(args->count);
}

static int nfs3_xdr_enc_commit3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs_writeargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_commit3args(&xdr, args);
        return 0;
}

#ifdef CONFIG_NFS_V3_ACL

static int nfs3_xdr_enc_getacl3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs3_getaclargs *args)
{
        struct xdr_stream xdr;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, args->fh);
        encode_uint32(&xdr, args->mask);
        if (args->mask & (NFS_ACL | NFS_DFACL))
                prepare_reply_buffer(req, args->pages, 0,
                                        NFSACL_MAXPAGES << PAGE_SHIFT,
                                        ACL3_getaclres_sz);
        return 0;
}

static int nfs3_xdr_enc_setacl3args(struct rpc_rqst *req, __be32 *p,
                                    const struct nfs3_setaclargs *args)
{
        struct xdr_stream xdr;
        unsigned int base;
        int error;

        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
        encode_nfs_fh3(&xdr, NFS_FH(args->inode));
        encode_uint32(&xdr, args->mask);
        if (args->npages != 0)
                xdr_write_pages(&xdr, args->pages, 0, args->len);

        base = req->rq_slen;
        error = nfsacl_encode(xdr.buf, base, args->inode,
                            (args->mask & NFS_ACL) ?
                            args->acl_access : NULL, 1, 0);
        BUG_ON(error < 0);
        error = nfsacl_encode(xdr.buf, base + error, args->inode,
                            (args->mask & NFS_DFACL) ?
                            args->acl_default : NULL, 1,
                            NFS_ACL_DEFAULT);
        BUG_ON(error < 0);
        return 0;
}

#endif  /* CONFIG_NFS_V3_ACL */

/*
 * NFS XDR decode functions
 */

/*
 * Decode attrstat reply.
 */
static int
nfs3_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
{
        int     status;

        if ((status = ntohl(*p++)))
                return nfs_stat_to_errno(status);
        xdr_decode_fattr(p, fattr);
        return 0;
}

/*
 * 3.3.1  GETATTR3res
 *
 *      struct GETATTR3resok {
 *              fattr3          obj_attributes;
 *      };
 *
 *      union GETATTR3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              GETATTR3resok  resok;
 *      default:
 *              void;
 *      };
 */
static int nfs3_xdr_dec_getattr3res(struct rpc_rqst *req, __be32 *p,
                                    struct nfs_fattr *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_fattr3(&xdr, result);
out:
        return error;
out_default:
        return nfs_stat_to_errno(status);
}

/*
 * Decode status+wcc_data reply
 * SATTR, REMOVE, RMDIR
 */
static int
nfs3_xdr_wccstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
{
        int     status;

        if ((status = ntohl(*p++)))
                status = nfs_stat_to_errno(status);
        xdr_decode_wcc_data(p, fattr);
        return status;
}

/*
 * 3.3.2  SETATTR3res
 *
 *      struct SETATTR3resok {
 *              wcc_data  obj_wcc;
 *      };
 *
 *      struct SETATTR3resfail {
 *              wcc_data  obj_wcc;
 *      };
 *
 *      union SETATTR3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              SETATTR3resok   resok;
 *      default:
 *              SETATTR3resfail resfail;
 *      };
 */
static int nfs3_xdr_dec_setattr3res(struct rpc_rqst *req, __be32 *p,
                                    struct nfs_fattr *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

static int
nfs3_xdr_removeres(struct rpc_rqst *req, __be32 *p, struct nfs_removeres *res)
{
        return nfs3_xdr_wccstat(req, p, res->dir_attr);
}

/*
 * Decode LOOKUP reply
 */
static int
nfs3_xdr_lookupres(struct rpc_rqst *req, __be32 *p, struct nfs3_diropres *res)
{
        int     status;

        if ((status = ntohl(*p++))) {
                status = nfs_stat_to_errno(status);
        } else {
                if (!(p = xdr_decode_fhandle(p, res->fh)))
                        return -errno_NFSERR_IO;
                p = xdr_decode_post_op_attr(p, res->fattr);
        }
        xdr_decode_post_op_attr(p, res->dir_attr);
        return status;
}

/*
 * 3.3.3  LOOKUP3res
 *
 *      struct LOOKUP3resok {
 *              nfs_fh3         object;
 *              post_op_attr    obj_attributes;
 *              post_op_attr    dir_attributes;
 *      };
 *
 *      struct LOOKUP3resfail {
 *              post_op_attr    dir_attributes;
 *      };
 *
 *      union LOOKUP3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              LOOKUP3resok    resok;
 *      default:
 *              LOOKUP3resfail  resfail;
 *      };
 */
static int nfs3_xdr_dec_lookup3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs3_diropres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_nfs_fh3(&xdr, result->fh);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->dir_attr);
out:
        return error;
out_default:
        error = decode_post_op_attr(&xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        return nfs_stat_to_errno(status);
}

/*
 * Decode ACCESS reply
 */
static int
nfs3_xdr_accessres(struct rpc_rqst *req, __be32 *p, struct nfs3_accessres *res)
{
        int     status = ntohl(*p++);

        p = xdr_decode_post_op_attr(p, res->fattr);
        if (status)
                return nfs_stat_to_errno(status);
        res->access = ntohl(*p++);
        return 0;
}

/*
 * 3.3.4  ACCESS3res
 *
 *      struct ACCESS3resok {
 *              post_op_attr    obj_attributes;
 *              uint32          access;
 *      };
 *
 *      struct ACCESS3resfail {
 *              post_op_attr    obj_attributes;
 *      };
 *
 *      union ACCESS3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              ACCESS3resok    resok;
 *      default:
 *              ACCESS3resfail  resfail;
 *      };
 */
static int nfs3_xdr_dec_access3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs3_accessres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_uint32(&xdr, &result->access);
out:
        return error;
out_default:
        return nfs_stat_to_errno(status);
}

/*
 * Decode READLINK reply
 */
static int
nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
{
        struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
        struct kvec *iov = rcvbuf->head;
        size_t hdrlen;
        u32 len, recvd;
        int     status;

        status = ntohl(*p++);
        p = xdr_decode_post_op_attr(p, fattr);

        if (status != 0)
                return nfs_stat_to_errno(status);

        /* Convert length of symlink */
        len = ntohl(*p++);
        if (len >= rcvbuf->page_len) {
                dprintk("nfs: server returned giant symlink!\n");
                return -ENAMETOOLONG;
        }

        hdrlen = (u8 *) p - (u8 *) iov->iov_base;
        if (iov->iov_len < hdrlen) {
                dprintk("NFS: READLINK reply header overflowed:"
                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                return -errno_NFSERR_IO;
        } else if (iov->iov_len != hdrlen) {
                dprintk("NFS: READLINK header is short. "
                        "iovec will be shifted.\n");
                xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
        }
        recvd = req->rq_rcv_buf.len - hdrlen;
        if (recvd < len) {
                dprintk("NFS: server cheating in readlink reply: "
                                "count %u > recvd %u\n", len, recvd);
                return -EIO;
        }

        xdr_terminate_string(rcvbuf, len);
        return 0;
}

/*
 * 3.3.5  READLINK3res
 *
 *      struct READLINK3resok {
 *              post_op_attr    symlink_attributes;
 *              nfspath3        data;
 *      };
 *
 *      struct READLINK3resfail {
 *              post_op_attr    symlink_attributes;
 *      };
 *
 *      union READLINK3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              READLINK3resok  resok;
 *      default:
 *              READLINK3resfail resfail;
 *      };
 */
static int nfs3_xdr_dec_readlink3res(struct rpc_rqst *req, __be32 *p,
                                     struct nfs_fattr *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_nfspath3(&xdr);
out:
        return error;
out_default:
        return nfs_stat_to_errno(status);
}

/*
 * Decode READ reply
 */
static int
nfs3_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
{
        struct kvec *iov = req->rq_rcv_buf.head;
        size_t hdrlen;
        u32 count, ocount, recvd;
        int status;

        status = ntohl(*p++);
        p = xdr_decode_post_op_attr(p, res->fattr);

        if (status != 0)
                return nfs_stat_to_errno(status);

        /* Decode reply count and EOF flag. NFSv3 is somewhat redundant
         * in that it puts the count both in the res struct and in the
         * opaque data count. */
        count    = ntohl(*p++);
        res->eof = ntohl(*p++);
        ocount   = ntohl(*p++);

        if (ocount != count) {
                dprintk("NFS: READ count doesn't match RPC opaque count.\n");
                return -errno_NFSERR_IO;
        }

        hdrlen = (u8 *) p - (u8 *) iov->iov_base;
        if (iov->iov_len < hdrlen) {
                dprintk("NFS: READ reply header overflowed:"
                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                return -errno_NFSERR_IO;
        } else if (iov->iov_len != hdrlen) {
                dprintk("NFS: READ header is short. iovec will be shifted.\n");
                xdr_shift_buf(&req->rq_rcv_buf, iov->iov_len - hdrlen);
        }

        recvd = req->rq_rcv_buf.len - hdrlen;
        if (count > recvd) {
                dprintk("NFS: server cheating in read reply: "
                        "count %u > recvd %u\n", count, recvd);
                count = recvd;
                res->eof = 0;
        }

        if (count < res->count)
                res->count = count;

        return count;
}

/*
 * 3.3.6  READ3res
 *
 *      struct READ3resok {
 *              post_op_attr    file_attributes;
 *              count3          count;
 *              bool            eof;
 *              opaque          data<>;
 *      };
 *
 *      struct READ3resfail {
 *              post_op_attr    file_attributes;
 *      };
 *
 *      union READ3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              READ3resok      resok;
 *      default:
 *              READ3resfail    resfail;
 *      };
 */
static int decode_read3resok(struct xdr_stream *xdr,
                             struct nfs_readres *result)
{
        u32 eof, count, ocount, recvd;
        size_t hdrlen;
        __be32 *p;

        p = xdr_inline_decode(xdr, 4 + 4 + 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        count = be32_to_cpup(p++);
        eof = be32_to_cpup(p++);
        ocount = be32_to_cpup(p++);
        if (unlikely(ocount != count))
                goto out_mismatch;
        hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base;
        recvd = xdr->buf->len - hdrlen;
        if (unlikely(count > recvd))
                goto out_cheating;

out:
        xdr_read_pages(xdr, count);
        result->eof = eof;
        result->count = count;
        return count;
out_mismatch:
        dprintk("NFS: READ count doesn't match length of opaque: "
                "count %u != ocount %u\n", count, ocount);
        return -EIO;
out_cheating:
        dprintk("NFS: server cheating in read result: "
                "count %u > recvd %u\n", count, recvd);
        count = recvd;
        eof = 0;
        goto out;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int nfs3_xdr_dec_read3res(struct rpc_rqst *req, __be32 *p,
                                 struct nfs_readres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_read3resok(&xdr, result);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode WRITE response
 */
static int
nfs3_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
{
        int     status;

        status = ntohl(*p++);
        p = xdr_decode_wcc_data(p, res->fattr);

        if (status != 0)
                return nfs_stat_to_errno(status);

        res->count = ntohl(*p++);
        res->verf->committed = (enum nfs3_stable_how)ntohl(*p++);
        res->verf->verifier[0] = *p++;
        res->verf->verifier[1] = *p++;

        return res->count;
}

/*
 * 3.3.7  WRITE3res
 *
 *      enum stable_how {
 *              UNSTABLE  = 0,
 *              DATA_SYNC = 1,
 *              FILE_SYNC = 2
 *      };
 *
 *      struct WRITE3resok {
 *              wcc_data        file_wcc;
 *              count3          count;
 *              stable_how      committed;
 *              writeverf3      verf;
 *      };
 *
 *      struct WRITE3resfail {
 *              wcc_data        file_wcc;
 *      };
 *
 *      union WRITE3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              WRITE3resok     resok;
 *      default:
 *              WRITE3resfail   resfail;
 *      };
 */
static int decode_write3resok(struct xdr_stream *xdr,
                              struct nfs_writeres *result)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4 + 4 + NFS3_WRITEVERFSIZE);
        if (unlikely(p == NULL))
                goto out_overflow;
        result->count = be32_to_cpup(p++);
        result->verf->committed = be32_to_cpup(p++);
        if (unlikely(result->verf->committed > NFS_FILE_SYNC))
                goto out_badvalue;
        memcpy(result->verf->verifier, p, NFS3_WRITEVERFSIZE);
        return result->count;
out_badvalue:
        dprintk("NFS: bad stable_how value: %u\n", result->verf->committed);
        return -EIO;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int nfs3_xdr_dec_write3res(struct rpc_rqst *req, __be32 *p,
                                  struct nfs_writeres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_write3resok(&xdr, result);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode a CREATE response
 */
static int
nfs3_xdr_createres(struct rpc_rqst *req, __be32 *p, struct nfs3_diropres *res)
{
        int     status;

        status = ntohl(*p++);
        if (status == 0) {
                if (*p++) {
                        if (!(p = xdr_decode_fhandle(p, res->fh)))
                                return -errno_NFSERR_IO;
                        p = xdr_decode_post_op_attr(p, res->fattr);
                } else {
                        memset(res->fh, 0, sizeof(*res->fh));
                        /* Do decode post_op_attr but set it to NULL */
                        p = xdr_decode_post_op_attr(p, res->fattr);
                        res->fattr->valid = 0;
                }
        } else {
                status = nfs_stat_to_errno(status);
        }
        p = xdr_decode_wcc_data(p, res->dir_attr);
        return status;
}

/*
 * 3.3.8  CREATE3res
 *
 *      struct CREATE3resok {
 *              post_op_fh3     obj;
 *              post_op_attr    obj_attributes;
 *              wcc_data        dir_wcc;
 *      };
 *
 *      struct CREATE3resfail {
 *              wcc_data        dir_wcc;
 *      };
 *
 *      union CREATE3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              CREATE3resok    resok;
 *      default:
 *              CREATE3resfail  resfail;
 *      };
 */
static int decode_create3resok(struct xdr_stream *xdr,
                               struct nfs3_diropres *result)
{
        int error;

        error = decode_post_op_fh3(xdr, result->fh);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(xdr, result->fattr);
        if (unlikely(error))
                goto out;
        /* The server isn't required to return a file handle.
         * If it didn't, force the client to perform a LOOKUP
         * to determine the correct file handle and attribute
         * values for the new object. */
        if (result->fh->size == 0)
                result->fattr->valid = 0;
        error = decode_wcc_data(xdr, result->dir_attr);
out:
        return error;
}

static int nfs3_xdr_dec_create3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs3_diropres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_create3resok(&xdr, result);
out:
        return error;
out_default:
        error = decode_wcc_data(&xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        return nfs_stat_to_errno(status);
}

/*
 * 3.3.12  REMOVE3res
 *
 *      struct REMOVE3resok {
 *              wcc_data    dir_wcc;
 *      };
 *
 *      struct REMOVE3resfail {
 *              wcc_data    dir_wcc;
 *      };
 *
 *      union REMOVE3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              REMOVE3resok   resok;
 *      default:
 *              REMOVE3resfail resfail;
 *      };
 */
static int nfs3_xdr_dec_remove3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_removeres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode RENAME reply
 */
static int
nfs3_xdr_renameres(struct rpc_rqst *req, __be32 *p, struct nfs_renameres *res)
{
        int     status;

        if ((status = ntohl(*p++)) != 0)
                status = nfs_stat_to_errno(status);
        p = xdr_decode_wcc_data(p, res->old_fattr);
        p = xdr_decode_wcc_data(p, res->new_fattr);
        return status;
}

/*
 * 3.3.14  RENAME3res
 *
 *      struct RENAME3resok {
 *              wcc_data        fromdir_wcc;
 *              wcc_data        todir_wcc;
 *      };
 *
 *      struct RENAME3resfail {
 *              wcc_data        fromdir_wcc;
 *              wcc_data        todir_wcc;
 *      };
 *
 *      union RENAME3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              RENAME3resok   resok;
 *      default:
 *              RENAME3resfail resfail;
 *      };
 */
static int nfs3_xdr_dec_rename3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_renameres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->old_fattr);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->new_fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode LINK reply
 */
static int
nfs3_xdr_linkres(struct rpc_rqst *req, __be32 *p, struct nfs3_linkres *res)
{
        int     status;

        if ((status = ntohl(*p++)) != 0)
                status = nfs_stat_to_errno(status);
        p = xdr_decode_post_op_attr(p, res->fattr);
        p = xdr_decode_wcc_data(p, res->dir_attr);
        return status;
}

/*
 * 3.3.15  LINK3res
 *
 *      struct LINK3resok {
 *              post_op_attr    file_attributes;
 *              wcc_data        linkdir_wcc;
 *      };
 *
 *      struct LINK3resfail {
 *              post_op_attr    file_attributes;
 *              wcc_data        linkdir_wcc;
 *      };
 *
 *      union LINK3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              LINK3resok      resok;
 *      default:
 *              LINK3resfail    resfail;
 *      };
 */
static int nfs3_xdr_dec_link3res(struct rpc_rqst *req, __be32 *p,
                                 struct nfs3_linkres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/**
 * nfs3_decode_dirent - Decode a single NFSv3 directory entry stored in
 *                      the local page cache
 * @xdr: XDR stream where entry resides
 * @entry: buffer to fill in with entry data
 * @server: nfs_server data for this directory
 * @plus: boolean indicating whether this should be a readdirplus entry
 *
 * Returns the position of the next item in the buffer, or an ERR_PTR.
 *
 * This function is not invoked during READDIR reply decoding, but
 * rather whenever an application invokes the getdents(2) system call
 * on a directory already in our cache.
 *
 * 3.3.16  entry3
 *
 *      struct entry3 {
 *              fileid3         fileid;
 *              filename3       name;
 *              cookie3         cookie;
 *              fhandle3        filehandle;
 *              post_op_attr3   attributes;
 *              entry3          *nextentry;
 *      };
 *
 * 3.3.17  entryplus3
 *      struct entryplus3 {
 *              fileid3         fileid;
 *              filename3       name;
 *              cookie3         cookie;
 *              post_op_attr    name_attributes;
 *              post_op_fh3     name_handle;
 *              entryplus3      *nextentry;
 *      };
 */
__be32 *nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
                           struct nfs_server *server, int plus)
{
        struct nfs_entry old = *entry;
        __be32 *p;
        int error;

        p = xdr_inline_decode(xdr, 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        if (*p == xdr_zero) {
                p = xdr_inline_decode(xdr, 4);
                if (unlikely(p == NULL))
                        goto out_overflow;
                if (*p == xdr_zero)
                        return ERR_PTR(-EAGAIN);
                entry->eof = 1;
                return ERR_PTR(-EBADCOOKIE);
        }

        error = decode_fileid3(xdr, &entry->ino);
        if (unlikely(error))
                return ERR_PTR(error);

        error = decode_inline_filename3(xdr, &entry->name, &entry->len);
        if (unlikely(error))
                return ERR_PTR(error);

        entry->prev_cookie = entry->cookie;
        error = decode_cookie3(xdr, &entry->cookie);
        if (unlikely(error))
                return ERR_PTR(error);

        entry->d_type = DT_UNKNOWN;

        if (plus) {
                entry->fattr->valid = 0;
                error = decode_post_op_attr(xdr, entry->fattr);
                if (unlikely(error))
                        return ERR_PTR(error);
                if (entry->fattr->valid & NFS_ATTR_FATTR_V3)
                        entry->d_type = nfs_umode_to_dtype(entry->fattr->mode);

                /* In fact, a post_op_fh3: */
                p = xdr_inline_decode(xdr, 4);
                if (unlikely(p == NULL))
                        goto out_overflow;
                if (*p != xdr_zero) {
                        error = decode_nfs_fh3(xdr, entry->fh);
                        if (unlikely(error)) {
                                if (error == -E2BIG)
                                        goto out_truncated;
                                return ERR_PTR(error);
                        }
                } else
                        zero_nfs_fh3(entry->fh);
        }

        /* Peek at the next entry to see if we're at EOD */
        p = xdr_inline_peek(xdr, 4 + 4);
        entry->eof = 0;
        if (p != NULL)
                entry->eof = (p[0] == xdr_zero) && (p[1] != xdr_zero);
        return p;

out_overflow:
        print_overflow_msg(__func__, xdr);
        return ERR_PTR(-EAGAIN);
out_truncated:
        dprintk("NFS: directory entry contains invalid file handle\n");
        *entry = old;
        return ERR_PTR(-EAGAIN);
}

/*
 * 3.3.16  READDIR3res
 *
 *      struct dirlist3 {
 *              entry3          *entries;
 *              bool            eof;
 *      };
 *
 *      struct READDIR3resok {
 *              post_op_attr    dir_attributes;
 *              cookieverf3     cookieverf;
 *              dirlist3        reply;
 *      };
 *
 *      struct READDIR3resfail {
 *              post_op_attr    dir_attributes;
 *      };
 *
 *      union READDIR3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              READDIR3resok   resok;
 *      default:
 *              READDIR3resfail resfail;
 *      };
 *
 * Read the directory contents into the page cache, but otherwise
 * don't touch them.  The actual decoding is done by nfs3_decode_entry()
 * during subsequent nfs_readdir() calls.
 */
static int decode_dirlist3(struct xdr_stream *xdr)
{
        u32 recvd, pglen;
        size_t hdrlen;

        pglen = xdr->buf->page_len;
        hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base;
        recvd = xdr->buf->len - hdrlen;
        if (unlikely(pglen > recvd))
                goto out_cheating;
out:
        xdr_read_pages(xdr, pglen);
        return pglen;
out_cheating:
        dprintk("NFS: server cheating in readdir result: "
                "pglen %u > recvd %u\n", pglen, recvd);
        pglen = recvd;
        goto out;
}

static int decode_readdir3resok(struct xdr_stream *xdr,
                                struct nfs3_readdirres *result)
{
        int error;

        error = decode_post_op_attr(xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        /* XXX: do we need to check if result->verf != NULL ? */
        error = decode_cookieverf3(xdr, result->verf);
        if (unlikely(error))
                goto out;
        error = decode_dirlist3(xdr);
out:
        return error;
}

static int nfs3_xdr_dec_readdir3res(struct rpc_rqst *req, __be32 *p,
                                    struct nfs3_readdirres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_readdir3resok(&xdr, result);
out:
        return error;
out_default:
        error = decode_post_op_attr(&xdr, result->dir_attr);
        if (unlikely(error))
                goto out;
        return nfs_stat_to_errno(status);
}

/*
 * Decode FSSTAT reply
 */
static int
nfs3_xdr_fsstatres(struct rpc_rqst *req, __be32 *p, struct nfs_fsstat *res)
{
        int             status;

        status = ntohl(*p++);

        p = xdr_decode_post_op_attr(p, res->fattr);
        if (status != 0)
                return nfs_stat_to_errno(status);

        p = xdr_decode_hyper(p, &res->tbytes);
        p = xdr_decode_hyper(p, &res->fbytes);
        p = xdr_decode_hyper(p, &res->abytes);
        p = xdr_decode_hyper(p, &res->tfiles);
        p = xdr_decode_hyper(p, &res->ffiles);
        p = xdr_decode_hyper(p, &res->afiles);

        /* ignore invarsec */
        return 0;
}

/*
 * 3.3.18  FSSTAT3res
 *
 *      struct FSSTAT3resok {
 *              post_op_attr    obj_attributes;
 *              size3           tbytes;
 *              size3           fbytes;
 *              size3           abytes;
 *              size3           tfiles;
 *              size3           ffiles;
 *              size3           afiles;
 *              uint32          invarsec;
 *      };
 *
 *      struct FSSTAT3resfail {
 *              post_op_attr    obj_attributes;
 *      };
 *
 *      union FSSTAT3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              FSSTAT3resok    resok;
 *      default:
 *              FSSTAT3resfail  resfail;
 *      };
 */
static int decode_fsstat3resok(struct xdr_stream *xdr,
                               struct nfs_fsstat *result)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 8 * 6 + 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        p = xdr_decode_size3(p, &result->tbytes);
        p = xdr_decode_size3(p, &result->fbytes);
        p = xdr_decode_size3(p, &result->abytes);
        p = xdr_decode_size3(p, &result->tfiles);
        p = xdr_decode_size3(p, &result->ffiles);
        xdr_decode_size3(p, &result->afiles);
        /* ignore invarsec */
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int nfs3_xdr_dec_fsstat3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_fsstat *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_fsstat3resok(&xdr, result);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode FSINFO reply
 */
static int
nfs3_xdr_fsinfores(struct rpc_rqst *req, __be32 *p, struct nfs_fsinfo *res)
{
        int             status;

        status = ntohl(*p++);

        p = xdr_decode_post_op_attr(p, res->fattr);
        if (status != 0)
                return nfs_stat_to_errno(status);

        res->rtmax  = ntohl(*p++);
        res->rtpref = ntohl(*p++);
        res->rtmult = ntohl(*p++);
        res->wtmax  = ntohl(*p++);
        res->wtpref = ntohl(*p++);
        res->wtmult = ntohl(*p++);
        res->dtpref = ntohl(*p++);
        p = xdr_decode_hyper(p, &res->maxfilesize);
        p = xdr_decode_time3(p, &res->time_delta);

        /* ignore properties */
        res->lease_time = 0;
        return 0;
}

/*
 * 3.3.19  FSINFO3res
 *
 *      struct FSINFO3resok {
 *              post_op_attr    obj_attributes;
 *              uint32          rtmax;
 *              uint32          rtpref;
 *              uint32          rtmult;
 *              uint32          wtmax;
 *              uint32          wtpref;
 *              uint32          wtmult;
 *              uint32          dtpref;
 *              size3           maxfilesize;
 *              nfstime3        time_delta;
 *              uint32          properties;
 *      };
 *
 *      struct FSINFO3resfail {
 *              post_op_attr    obj_attributes;
 *      };
 *
 *      union FSINFO3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              FSINFO3resok    resok;
 *      default:
 *              FSINFO3resfail  resfail;
 *      };
 */
static int decode_fsinfo3resok(struct xdr_stream *xdr,
                               struct nfs_fsinfo *result)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4 * 7 + 8 + 8 + 4);
        if (unlikely(p == NULL))
                goto out_overflow;
        result->rtmax  = be32_to_cpup(p++);
        result->rtpref = be32_to_cpup(p++);
        result->rtmult = be32_to_cpup(p++);
        result->wtmax  = be32_to_cpup(p++);
        result->wtpref = be32_to_cpup(p++);
        result->wtmult = be32_to_cpup(p++);
        result->dtpref = be32_to_cpup(p++);
        p = xdr_decode_size3(p, &result->maxfilesize);
        xdr_decode_time3(p, &result->time_delta);

        /* ignore properties */
        result->lease_time = 0;
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int nfs3_xdr_dec_fsinfo3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_fsinfo *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_fsinfo3resok(&xdr, result);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode PATHCONF reply
 */
static int
nfs3_xdr_pathconfres(struct rpc_rqst *req, __be32 *p, struct nfs_pathconf *res)
{
        int             status;

        status = ntohl(*p++);

        p = xdr_decode_post_op_attr(p, res->fattr);
        if (status != 0)
                return nfs_stat_to_errno(status);
        res->max_link = ntohl(*p++);
        res->max_namelen = ntohl(*p++);

        /* ignore remaining fields */
        return 0;
}

/*
 * 3.3.20  PATHCONF3res
 *
 *      struct PATHCONF3resok {
 *              post_op_attr    obj_attributes;
 *              uint32          linkmax;
 *              uint32          name_max;
 *              bool            no_trunc;
 *              bool            chown_restricted;
 *              bool            case_insensitive;
 *              bool            case_preserving;
 *      };
 *
 *      struct PATHCONF3resfail {
 *              post_op_attr    obj_attributes;
 *      };
 *
 *      union PATHCONF3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              PATHCONF3resok  resok;
 *      default:
 *              PATHCONF3resfail resfail;
 *      };
 */
static int decode_pathconf3resok(struct xdr_stream *xdr,
                                 struct nfs_pathconf *result)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, 4 * 6);
        if (unlikely(p == NULL))
                goto out_overflow;
        result->max_link = be32_to_cpup(p++);
        result->max_namelen = be32_to_cpup(p);
        /* ignore remaining fields */
        return 0;
out_overflow:
        print_overflow_msg(__func__, xdr);
        return -EIO;
}

static int nfs3_xdr_dec_pathconf3res(struct rpc_rqst *req, __be32 *p,
                                     struct nfs_pathconf *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_post_op_attr(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_pathconf3resok(&xdr, result);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

/*
 * Decode COMMIT reply
 */
static int
nfs3_xdr_commitres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
{
        int             status;

        status = ntohl(*p++);
        p = xdr_decode_wcc_data(p, res->fattr);
        if (status != 0)
                return nfs_stat_to_errno(status);

        res->verf->verifier[0] = *p++;
        res->verf->verifier[1] = *p++;
        return 0;
}

/*
 * 3.3.21  COMMIT3res
 *
 *      struct COMMIT3resok {
 *              wcc_data        file_wcc;
 *              writeverf3      verf;
 *      };
 *
 *      struct COMMIT3resfail {
 *              wcc_data        file_wcc;
 *      };
 *
 *      union COMMIT3res switch (nfsstat3 status) {
 *      case NFS3_OK:
 *              COMMIT3resok    resok;
 *      default:
 *              COMMIT3resfail  resfail;
 *      };
 */
static int nfs3_xdr_dec_commit3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_writeres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        error = decode_wcc_data(&xdr, result->fattr);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_status;
        error = decode_writeverf3(&xdr, result->verf->verifier);
out:
        return error;
out_status:
        return nfs_stat_to_errno(status);
}

#ifdef CONFIG_NFS_V3_ACL
/*
 * Decode GETACL reply
 */
static int
nfs3_xdr_getaclres(struct rpc_rqst *req, __be32 *p,
                   struct nfs3_getaclres *res)
{
        struct xdr_buf *buf = &req->rq_rcv_buf;
        int status = ntohl(*p++);
        struct posix_acl **acl;
        unsigned int *aclcnt;
        int err, base;

        if (status != 0)
                return nfs_stat_to_errno(status);
        p = xdr_decode_post_op_attr(p, res->fattr);
        res->mask = ntohl(*p++);
        if (res->mask & ~(NFS_ACL|NFS_ACLCNT|NFS_DFACL|NFS_DFACLCNT))
                return -EINVAL;
        base = (char *)p - (char *)req->rq_rcv_buf.head->iov_base;

        acl = (res->mask & NFS_ACL) ? &res->acl_access : NULL;
        aclcnt = (res->mask & NFS_ACLCNT) ? &res->acl_access_count : NULL;
        err = nfsacl_decode(buf, base, aclcnt, acl);

        acl = (res->mask & NFS_DFACL) ? &res->acl_default : NULL;
        aclcnt = (res->mask & NFS_DFACLCNT) ? &res->acl_default_count : NULL;
        if (err > 0)
                err = nfsacl_decode(buf, base + err, aclcnt, acl);
        return (err > 0) ? 0 : err;
}

static inline int decode_getacl3resok(struct xdr_stream *xdr,
                                      struct nfs3_getaclres *result)
{
        struct posix_acl **acl;
        unsigned int *aclcnt;
        size_t hdrlen;
        int error;

        error = decode_post_op_attr(xdr, result->fattr);
        if (unlikely(error))
                goto out;
        error = decode_uint32(xdr, &result->mask);
        if (unlikely(error))
                goto out;
        error = -EINVAL;
        if (result->mask & ~(NFS_ACL|NFS_ACLCNT|NFS_DFACL|NFS_DFACLCNT))
                goto out;

        hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base;

        acl = NULL;
        if (result->mask & NFS_ACL)
                acl = &result->acl_access;
        aclcnt = NULL;
        if (result->mask & NFS_ACLCNT)
                aclcnt = &result->acl_access_count;
        error = nfsacl_decode(xdr->buf, hdrlen, aclcnt, acl);
        if (unlikely(error <= 0))
                goto out;

        acl = NULL;
        if (result->mask & NFS_DFACL)
                acl = &result->acl_default;
        aclcnt = NULL;
        if (result->mask & NFS_DFACLCNT)
                aclcnt = &result->acl_default_count;
        error = nfsacl_decode(xdr->buf, hdrlen + error, aclcnt, acl);
        if (unlikely(error <= 0))
                return error;
        error = 0;
out:
        return error;
}

static int nfs3_xdr_dec_getacl3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs3_getaclres *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_getacl3resok(&xdr, result);
out:
        return error;
out_default:
        return nfs_stat_to_errno(status);
}

/*
 * Decode setacl reply.
 */
static int
nfs3_xdr_setaclres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
{
        int status = ntohl(*p++);

        if (status)
                return nfs_stat_to_errno(status);
        xdr_decode_post_op_attr(p, fattr);
        return 0;
}

static int nfs3_xdr_dec_setacl3res(struct rpc_rqst *req, __be32 *p,
                                   struct nfs_fattr *result)
{
        struct xdr_stream xdr;
        enum nfs_stat status;
        int error;

        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
        error = decode_nfsstat3(&xdr, &status);
        if (unlikely(error))
                goto out;
        if (status != NFS3_OK)
                goto out_default;
        error = decode_post_op_attr(&xdr, result);
out:
        return error;
out_default:
        return nfs_stat_to_errno(status);
}

#endif  /* CONFIG_NFS_V3_ACL */

#define PROC(proc, argtype, restype, timer)                             \
[NFS3PROC_##proc] = {                                                   \
        .p_proc      = NFS3PROC_##proc,                                 \
        .p_encode    = (kxdrproc_t)nfs3_xdr_enc_##argtype##3args,       \
        .p_decode    = (kxdrproc_t) nfs3_xdr_##restype,                 \
        .p_arglen    = NFS3_##argtype##args_sz,                         \
        .p_replen    = NFS3_##restype##_sz,                             \
        .p_timer     = timer,                                           \
        .p_statidx   = NFS3PROC_##proc,                                 \
        .p_name      = #proc,                                           \
        }

struct rpc_procinfo     nfs3_procedures[] = {
        PROC(GETATTR,           getattr,        attrstat,       1),
        PROC(SETATTR,           setattr,        wccstat,        0),
        PROC(LOOKUP,            lookup,         lookupres,      2),
        PROC(ACCESS,            access,         accessres,      1),
        PROC(READLINK,          readlink,       readlinkres,    3),
        PROC(READ,              read,           readres,        3),
        PROC(WRITE,             write,          writeres,       4),
        PROC(CREATE,            create,         createres,      0),
        PROC(MKDIR,             mkdir,          createres,      0),
        PROC(SYMLINK,           symlink,        createres,      0),
        PROC(MKNOD,             mknod,          createres,      0),
        PROC(REMOVE,            remove,         removeres,      0),
        PROC(RMDIR,             lookup,         wccstat,        0),
        PROC(RENAME,            rename,         renameres,      0),
        PROC(LINK,              link,           linkres,        0),
        PROC(READDIR,           readdir,        readdirres,     3),
        PROC(READDIRPLUS,       readdirplus,    readdirres,     3),
        PROC(FSSTAT,            getattr,        fsstatres,      0),
        PROC(FSINFO,            getattr,        fsinfores,      0),
        PROC(PATHCONF,          getattr,        pathconfres,    0),
        PROC(COMMIT,            commit,         commitres,      5),
};

struct rpc_version              nfs_version3 = {
        .number                 = 3,
        .nrprocs                = ARRAY_SIZE(nfs3_procedures),
        .procs                  = nfs3_procedures
};

#ifdef CONFIG_NFS_V3_ACL
static struct rpc_procinfo      nfs3_acl_procedures[] = {
        [ACLPROC3_GETACL] = {
                .p_proc = ACLPROC3_GETACL,
                .p_encode = (kxdrproc_t)nfs3_xdr_enc_getacl3args,
                .p_decode = (kxdrproc_t) nfs3_xdr_getaclres,
                .p_arglen = ACL3_getaclargs_sz,
                .p_replen = ACL3_getaclres_sz,
                .p_timer = 1,
                .p_name = "GETACL",
        },
        [ACLPROC3_SETACL] = {
                .p_proc = ACLPROC3_SETACL,
                .p_encode = (kxdrproc_t)nfs3_xdr_enc_setacl3args,
                .p_decode = (kxdrproc_t) nfs3_xdr_setaclres,
                .p_arglen = ACL3_setaclargs_sz,
                .p_replen = ACL3_setaclres_sz,
                .p_timer = 0,
                .p_name = "SETACL",
        },
};

struct rpc_version              nfsacl_version3 = {
        .number                 = 3,
        .nrprocs                = sizeof(nfs3_acl_procedures)/
                                  sizeof(nfs3_acl_procedures[0]),
        .procs                  = nfs3_acl_procedures,
};
#endif  /* CONFIG_NFS_V3_ACL */