fs/nfs/nfs2xdr.c

   1 /*
   2  * linux/fs/nfs/nfs2xdr.c
   3  *
   4  * XDR functions to encode/decode NFS RPC arguments and results.
   5  *
   6  * Copyright (C) 1992, 1993, 1994  Rick Sladkey
   7  * Copyright (C) 1996 Olaf Kirch
   8  * 04 Aug 1998  Ion Badulescu <ionut@cs.columbia.edu>
   9  *              FIFO's need special handling in NFSv2
  10  */
  11
  12 #include <linux/param.h>
  13 #include <linux/time.h>
  14 #include <linux/mm.h>
  15 #include <linux/slab.h>
  16 #include <linux/errno.h>
  17 #include <linux/string.h>
  18 #include <linux/in.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/sunrpc/clnt.h>
  22 #include <linux/nfs.h>
  23 #include <linux/nfs2.h>
  24 #include <linux/nfs_fs.h>
  25 #include "internal.h"
  26
  27 #define NFSDBG_FACILITY         NFSDBG_XDR
  28
  29 /* Mapping from NFS error code to "errno" error code. */
  30 #define errno_NFSERR_IO         EIO
  31
  32 /*
  33  * Declare the space requirements for NFS arguments and replies as
  34  * number of 32bit-words
  35  */
  36 #define NFS_fhandle_sz          (8)
  37 #define NFS_sattr_sz            (8)
  38 #define NFS_filename_sz         (1+(NFS2_MAXNAMLEN>>2))
  39 #define NFS_path_sz             (1+(NFS2_MAXPATHLEN>>2))
  40 #define NFS_fattr_sz            (17)
  41 #define NFS_info_sz             (5)
  42 #define NFS_entry_sz            (NFS_filename_sz+3)
  43
  44 #define NFS_diropargs_sz        (NFS_fhandle_sz+NFS_filename_sz)
  45 #define NFS_removeargs_sz       (NFS_fhandle_sz+NFS_filename_sz)
  46 #define NFS_sattrargs_sz        (NFS_fhandle_sz+NFS_sattr_sz)
  47 #define NFS_readlinkargs_sz     (NFS_fhandle_sz)
  48 #define NFS_readargs_sz         (NFS_fhandle_sz+3)
  49 #define NFS_writeargs_sz        (NFS_fhandle_sz+4)
  50 #define NFS_createargs_sz       (NFS_diropargs_sz+NFS_sattr_sz)
  51 #define NFS_renameargs_sz       (NFS_diropargs_sz+NFS_diropargs_sz)
  52 #define NFS_linkargs_sz         (NFS_fhandle_sz+NFS_diropargs_sz)
  53 #define NFS_symlinkargs_sz      (NFS_diropargs_sz+1+NFS_sattr_sz)
  54 #define NFS_readdirargs_sz      (NFS_fhandle_sz+2)
  55
  56 #define NFS_attrstat_sz         (1+NFS_fattr_sz)
  57 #define NFS_diropres_sz         (1+NFS_fhandle_sz+NFS_fattr_sz)
  58 #define NFS_readlinkres_sz      (2)
  59 #define NFS_readres_sz          (1+NFS_fattr_sz+1)
  60 #define NFS_writeres_sz         (NFS_attrstat_sz)
  61 #define NFS_stat_sz             (1)
  62 #define NFS_readdirres_sz       (1)
  63 #define NFS_statfsres_sz        (1+NFS_info_sz)
  64
  65 /*
  66  * Common NFS XDR functions as inlines
  67  */
  68 static inline __be32 *
  69 xdr_encode_fhandle(__be32 *p, const struct nfs_fh *fhandle)
  70 {
  71         memcpy(p, fhandle->data, NFS2_FHSIZE);
  72         return p + XDR_QUADLEN(NFS2_FHSIZE);
  73 }
  74
  75 static inline __be32 *
  76 xdr_decode_fhandle(__be32 *p, struct nfs_fh *fhandle)
  77 {
  78         /* NFSv2 handles have a fixed length */
  79         fhandle->size = NFS2_FHSIZE;
  80         memcpy(fhandle->data, p, NFS2_FHSIZE);
  81         return p + XDR_QUADLEN(NFS2_FHSIZE);
  82 }
  83
  84 static inline __be32*
  85 xdr_encode_time(__be32 *p, struct timespec *timep)
  86 {
  87         *p++ = htonl(timep->tv_sec);
  88         /* Convert nanoseconds into microseconds */
  89         *p++ = htonl(timep->tv_nsec ? timep->tv_nsec / 1000 : 0);
  90         return p;
  91 }
  92
  93 static inline __be32*
  94 xdr_encode_current_server_time(__be32 *p, struct timespec *timep)
  95 {
  96         /*
  97          * Passing the invalid value useconds=1000000 is a
  98          * Sun convention for "set to current server time".
  99          * It's needed to make permissions checks for the
 100          * "touch" program across v2 mounts to Solaris and
 101          * Irix boxes work correctly. See description of
 102          * sattr in section 6.1 of "NFS Illustrated" by
 103          * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
 104          */
 105         *p++ = htonl(timep->tv_sec);
 106         *p++ = htonl(1000000);
 107         return p;
 108 }
 109
 110 static inline __be32*
 111 xdr_decode_time(__be32 *p, struct timespec *timep)
 112 {
 113         timep->tv_sec = ntohl(*p++);
 114         /* Convert microseconds into nanoseconds */
 115         timep->tv_nsec = ntohl(*p++) * 1000;
 116         return p;
 117 }
 118
 119 static __be32 *
 120 xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr)
 121 {
 122         u32 rdev, type;
 123         type = ntohl(*p++);
 124         fattr->mode = ntohl(*p++);
 125         fattr->nlink = ntohl(*p++);
 126         fattr->uid = ntohl(*p++);
 127         fattr->gid = ntohl(*p++);
 128         fattr->size = ntohl(*p++);
 129         fattr->du.nfs2.blocksize = ntohl(*p++);
 130         rdev = ntohl(*p++);
 131         fattr->du.nfs2.blocks = ntohl(*p++);
 132         fattr->fsid.major = ntohl(*p++);
 133         fattr->fsid.minor = 0;
 134         fattr->fileid = ntohl(*p++);
 135         p = xdr_decode_time(p, &fattr->atime);
 136         p = xdr_decode_time(p, &fattr->mtime);
 137         p = xdr_decode_time(p, &fattr->ctime);
 138         fattr->valid |= NFS_ATTR_FATTR_V2;
 139         fattr->rdev = new_decode_dev(rdev);
 140         if (type == NFCHR && rdev == NFS2_FIFO_DEV) {
 141                 fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
 142                 fattr->rdev = 0;
 143         }
 144         return p;
 145 }
 146
 147 static inline __be32 *
 148 xdr_encode_sattr(__be32 *p, struct iattr *attr)
 149 {
 150         const __be32 not_set = __constant_htonl(0xFFFFFFFF);
 151
 152         *p++ = (attr->ia_valid & ATTR_MODE) ? htonl(attr->ia_mode) : not_set;
 153         *p++ = (attr->ia_valid & ATTR_UID) ? htonl(attr->ia_uid) : not_set;
 154         *p++ = (attr->ia_valid & ATTR_GID) ? htonl(attr->ia_gid) : not_set;
 155         *p++ = (attr->ia_valid & ATTR_SIZE) ? htonl(attr->ia_size) : not_set;
 156
 157         if (attr->ia_valid & ATTR_ATIME_SET) {
 158                 p = xdr_encode_time(p, &attr->ia_atime);
 159         } else if (attr->ia_valid & ATTR_ATIME) {
 160                 p = xdr_encode_current_server_time(p, &attr->ia_atime);
 161         } else {
 162                 *p++ = not_set;
 163                 *p++ = not_set;
 164         }
 165
 166         if (attr->ia_valid & ATTR_MTIME_SET) {
 167                 p = xdr_encode_time(p, &attr->ia_mtime);
 168         } else if (attr->ia_valid & ATTR_MTIME) {
 169                 p = xdr_encode_current_server_time(p, &attr->ia_mtime);
 170         } else {
 171                 *p++ = not_set;
 172                 *p++ = not_set;
 173         }
 174         return p;
 175 }
 176
 177 /*
 178  * NFS encode functions
 179  */
 180 /*
 181  * Encode file handle argument
 182  * GETATTR, READLINK, STATFS
 183  */
 184 static int
 185 nfs_xdr_fhandle(struct rpc_rqst *req, __be32 *p, struct nfs_fh *fh)
 186 {
 187         p = xdr_encode_fhandle(p, fh);
 188         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 189         return 0;
 190 }
 191
 192 /*
 193  * Encode SETATTR arguments
 194  */
 195 static int
 196 nfs_xdr_sattrargs(struct rpc_rqst *req, __be32 *p, struct nfs_sattrargs *args)
 197 {
 198         p = xdr_encode_fhandle(p, args->fh);
 199         p = xdr_encode_sattr(p, args->sattr);
 200         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 201         return 0;
 202 }
 203
 204 /*
 205  * Encode directory ops argument
 206  * LOOKUP, RMDIR
 207  */
 208 static int
 209 nfs_xdr_diropargs(struct rpc_rqst *req, __be32 *p, struct nfs_diropargs *args)
 210 {
 211         p = xdr_encode_fhandle(p, args->fh);
 212         p = xdr_encode_array(p, args->name, args->len);
 213         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 214         return 0;
 215 }
 216
 217 /*
 218  * Encode REMOVE argument
 219  */
 220 static int
 221 nfs_xdr_removeargs(struct rpc_rqst *req, __be32 *p, const struct nfs_removeargs *args)
 222 {
 223         p = xdr_encode_fhandle(p, args->fh);
 224         p = xdr_encode_array(p, args->name.name, args->name.len);
 225         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 226         return 0;
 227 }
 228
 229 /*
 230  * Arguments to a READ call. Since we read data directly into the page
 231  * cache, we also set up the reply iovec here so that iov[1] points
 232  * exactly to the page we want to fetch.
 233  */
 234 static int
 235 nfs_xdr_readargs(struct rpc_rqst *req, __be32 *p, struct nfs_readargs *args)
 236 {
 237         struct rpc_auth *auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
 238         unsigned int replen;
 239         u32 offset = (u32)args->offset;
 240         u32 count = args->count;
 241
 242         p = xdr_encode_fhandle(p, args->fh);
 243         *p++ = htonl(offset);
 244         *p++ = htonl(count);
 245         *p++ = htonl(count);
 246         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 247
 248         /* Inline the page array */
 249         replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readres_sz) << 2;
 250         xdr_inline_pages(&req->rq_rcv_buf, replen,
 251                          args->pages, args->pgbase, count);
 252         req->rq_rcv_buf.flags |= XDRBUF_READ;
 253         return 0;
 254 }
 255
 256 /*
 257  * Decode READ reply
 258  */
 259 static int
 260 nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
 261 {
 262         struct kvec *iov = req->rq_rcv_buf.head;
 263         size_t hdrlen;
 264         u32 count, recvd;
 265         int status;
 266
 267         if ((status = ntohl(*p++)))
 268                 return nfs_stat_to_errno(status);
 269         p = xdr_decode_fattr(p, res->fattr);
 270
 271         count = ntohl(*p++);
 272         res->eof = 0;
 273         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
 274         if (iov->iov_len < hdrlen) {
 275                 dprintk("NFS: READ reply header overflowed:"
 276                                 "length %Zu > %Zu\n", hdrlen, iov->iov_len);
 277                 return -errno_NFSERR_IO;
 278         } else if (iov->iov_len != hdrlen) {
 279                 dprintk("NFS: READ header is short. iovec will be shifted.\n");
 280                 xdr_shift_buf(&req->rq_rcv_buf, iov->iov_len - hdrlen);
 281         }
 282
 283         recvd = req->rq_rcv_buf.len - hdrlen;
 284         if (count > recvd) {
 285                 dprintk("NFS: server cheating in read reply: "
 286                         "count %u > recvd %u\n", count, recvd);
 287                 count = recvd;
 288         }
 289
 290         dprintk("RPC:      readres OK count %u\n", count);
 291         if (count < res->count)
 292                 res->count = count;
 293
 294         return count;
 295 }
 296
 297
 298 /*
 299  * Write arguments. Splice the buffer to be written into the iovec.
 300  */
 301 static int
 302 nfs_xdr_writeargs(struct rpc_rqst *req, __be32 *p, struct nfs_writeargs *args)
 303 {
 304         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 305         u32 offset = (u32)args->offset;
 306         u32 count = args->count;
 307
 308         p = xdr_encode_fhandle(p, args->fh);
 309         *p++ = htonl(offset);
 310         *p++ = htonl(offset);
 311         *p++ = htonl(count);
 312         *p++ = htonl(count);
 313         sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
 314
 315         /* Copy the page array */
 316         xdr_encode_pages(sndbuf, args->pages, args->pgbase, count);
 317         sndbuf->flags |= XDRBUF_WRITE;
 318         return 0;
 319 }
 320
 321 /*
 322  * Encode create arguments
 323  * CREATE, MKDIR
 324  */
 325 static int
 326 nfs_xdr_createargs(struct rpc_rqst *req, __be32 *p, struct nfs_createargs *args)
 327 {
 328         p = xdr_encode_fhandle(p, args->fh);
 329         p = xdr_encode_array(p, args->name, args->len);
 330         p = xdr_encode_sattr(p, args->sattr);
 331         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 332         return 0;
 333 }
 334
 335 /*
 336  * Encode RENAME arguments
 337  */
 338 static int
 339 nfs_xdr_renameargs(struct rpc_rqst *req, __be32 *p, struct nfs_renameargs *args)
 340 {
 341         p = xdr_encode_fhandle(p, args->fromfh);
 342         p = xdr_encode_array(p, args->fromname, args->fromlen);
 343         p = xdr_encode_fhandle(p, args->tofh);
 344         p = xdr_encode_array(p, args->toname, args->tolen);
 345         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 346         return 0;
 347 }
 348
 349 /*
 350  * Encode LINK arguments
 351  */
 352 static int
 353 nfs_xdr_linkargs(struct rpc_rqst *req, __be32 *p, struct nfs_linkargs *args)
 354 {
 355         p = xdr_encode_fhandle(p, args->fromfh);
 356         p = xdr_encode_fhandle(p, args->tofh);
 357         p = xdr_encode_array(p, args->toname, args->tolen);
 358         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 359         return 0;
 360 }
 361
 362 /*
 363  * Encode SYMLINK arguments
 364  */
 365 static int
 366 nfs_xdr_symlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_symlinkargs *args)
 367 {
 368         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 369         size_t pad;
 370
 371         p = xdr_encode_fhandle(p, args->fromfh);
 372         p = xdr_encode_array(p, args->fromname, args->fromlen);
 373         *p++ = htonl(args->pathlen);
 374         sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
 375
 376         xdr_encode_pages(sndbuf, args->pages, 0, args->pathlen);
 377
 378         /*
 379          * xdr_encode_pages may have added a few bytes to ensure the
 380          * pathname ends on a 4-byte boundary.  Start encoding the
 381          * attributes after the pad bytes.
 382          */
 383         pad = sndbuf->tail->iov_len;
 384         if (pad > 0)
 385                 p++;
 386         p = xdr_encode_sattr(p, args->sattr);
 387         sndbuf->len += xdr_adjust_iovec(sndbuf->tail, p) - pad;
 388         return 0;
 389 }
 390
 391 /*
 392  * Encode arguments to readdir call
 393  */
 394 static int
 395 nfs_xdr_readdirargs(struct rpc_rqst *req, __be32 *p, struct nfs_readdirargs *args)
 396 {
 397         struct rpc_task *task = req->rq_task;
 398         struct rpc_auth *auth = task->tk_msg.rpc_cred->cr_auth;
 399         unsigned int replen;
 400         u32 count = args->count;
 401
 402         p = xdr_encode_fhandle(p, args->fh);
 403         *p++ = htonl(args->cookie);
 404         *p++ = htonl(count); /* see above */
 405         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 406
 407         /* Inline the page array */
 408         replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readdirres_sz) << 2;
 409         xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, 0, count);
 410         return 0;
 411 }
 412
 413 /*
 414  * Decode the result of a readdir call.
 415  * We're not really decoding anymore, we just leave the buffer untouched
 416  * and only check that it is syntactically correct.
 417  * The real decoding happens in nfs_decode_entry below, called directly
 418  * from nfs_readdir for each entry.
 419  */
 420 static int
 421 nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
 422 {
 423         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 424         struct kvec *iov = rcvbuf->head;
 425         struct page **page;
 426         size_t hdrlen;
 427         unsigned int pglen, recvd;
 428         u32 len;
 429         int status, nr = 0;
 430         __be32 *end, *entry, *kaddr;
 431
 432         if ((status = ntohl(*p++)))
 433                 return nfs_stat_to_errno(status);
 434
 435         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
 436         if (iov->iov_len < hdrlen) {
 437                 dprintk("NFS: READDIR reply header overflowed:"
 438                                 "length %Zu > %Zu\n", hdrlen, iov->iov_len);
 439                 return -errno_NFSERR_IO;
 440         } else if (iov->iov_len != hdrlen) {
 441                 dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
 442                 xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
 443         }
 444
 445         pglen = rcvbuf->page_len;
 446         recvd = rcvbuf->len - hdrlen;
 447         if (pglen > recvd)
 448                 pglen = recvd;
 449         page = rcvbuf->pages;
 450         kaddr = p = kmap_atomic(*page, KM_USER0);
 451         end = (__be32 *)((char *)p + pglen);
 452         entry = p;
 453
 454         /* Make sure the packet actually has a value_follows and EOF entry */
 455         if ((entry + 1) > end)
 456                 goto short_pkt;
 457
 458         for (; *p++; nr++) {
 459                 if (p + 2 > end)
 460                         goto short_pkt;
 461                 p++; /* fileid */
 462                 len = ntohl(*p++);
 463                 p += XDR_QUADLEN(len) + 1;      /* name plus cookie */
 464                 if (len > NFS2_MAXNAMLEN) {
 465                         dprintk("NFS: giant filename in readdir (len 0x%x)!\n",
 466                                                 len);
 467                         goto err_unmap;
 468                 }
 469                 if (p + 2 > end)
 470                         goto short_pkt;
 471                 entry = p;
 472         }
 473
 474         /*
 475          * Apparently some server sends responses that are a valid size, but
 476          * contain no entries, and have value_follows==0 and EOF==0. For
 477          * those, just set the EOF marker.
 478          */
 479         if (!nr && entry[1] == 0) {
 480                 dprintk("NFS: readdir reply truncated!\n");
 481                 entry[1] = 1;
 482         }
 483  out:
 484         kunmap_atomic(kaddr, KM_USER0);
 485         return nr;
 486  short_pkt:
 487         /*
 488          * When we get a short packet there are 2 possibilities. We can
 489          * return an error, or fix up the response to look like a valid
 490          * response and return what we have so far. If there are no
 491          * entries and the packet was short, then return -EIO. If there
 492          * are valid entries in the response, return them and pretend that
 493          * the call was successful, but incomplete. The caller can retry the
 494          * readdir starting at the last cookie.
 495          */
 496         entry[0] = entry[1] = 0;
 497         if (!nr)
 498                 nr = -errno_NFSERR_IO;
 499         goto out;
 500 err_unmap:
 501         nr = -errno_NFSERR_IO;
 502         goto out;
 503 }
 504
 505 __be32 *
 506 nfs_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus)
 507 {
 508         if (!*p++) {
 509                 if (!*p)
 510                         return ERR_PTR(-EAGAIN);
 511                 entry->eof = 1;
 512                 return ERR_PTR(-EBADCOOKIE);
 513         }
 514
 515         entry->ino        = ntohl(*p++);
 516         entry->len        = ntohl(*p++);
 517         entry->name       = (const char *) p;
 518         p                += XDR_QUADLEN(entry->len);
 519         entry->prev_cookie        = entry->cookie;
 520         entry->cookie     = ntohl(*p++);
 521         entry->eof        = !p[0] && p[1];
 522
 523         return p;
 524 }
 525
 526 /*
 527  * NFS XDR decode functions
 528  */
 529 /*
 530  * Decode simple status reply
 531  */
 532 static int
 533 nfs_xdr_stat(struct rpc_rqst *req, __be32 *p, void *dummy)
 534 {
 535         int     status;
 536
 537         if ((status = ntohl(*p++)) != 0)
 538                 status = nfs_stat_to_errno(status);
 539         return status;
 540 }
 541
 542 /*
 543  * Decode attrstat reply
 544  * GETATTR, SETATTR, WRITE
 545  */
 546 static int
 547 nfs_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
 548 {
 549         int     status;
 550
 551         if ((status = ntohl(*p++)))
 552                 return nfs_stat_to_errno(status);
 553         xdr_decode_fattr(p, fattr);
 554         return 0;
 555 }
 556
 557 /*
 558  * Decode diropres reply
 559  * LOOKUP, CREATE, MKDIR
 560  */
 561 static int
 562 nfs_xdr_diropres(struct rpc_rqst *req, __be32 *p, struct nfs_diropok *res)
 563 {
 564         int     status;
 565
 566         if ((status = ntohl(*p++)))
 567                 return nfs_stat_to_errno(status);
 568         p = xdr_decode_fhandle(p, res->fh);
 569         xdr_decode_fattr(p, res->fattr);
 570         return 0;
 571 }
 572
 573 /*
 574  * Encode READLINK args
 575  */
 576 static int
 577 nfs_xdr_readlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_readlinkargs *args)
 578 {
 579         struct rpc_auth *auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
 580         unsigned int replen;
 581
 582         p = xdr_encode_fhandle(p, args->fh);
 583         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 584
 585         /* Inline the page array */
 586         replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readlinkres_sz) << 2;
 587         xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, args->pgbase, args->pglen);
 588         return 0;
 589 }
 590
 591 /*
 592  * Decode READLINK reply
 593  */
 594 static int
 595 nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
 596 {
 597         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 598         struct kvec *iov = rcvbuf->head;
 599         size_t hdrlen;
 600         u32 len, recvd;
 601         char    *kaddr;
 602         int     status;
 603
 604         if ((status = ntohl(*p++)))
 605                 return nfs_stat_to_errno(status);
 606         /* Convert length of symlink */
 607         len = ntohl(*p++);
 608         if (len >= rcvbuf->page_len) {
 609                 dprintk("nfs: server returned giant symlink!\n");
 610                 return -ENAMETOOLONG;
 611         }
 612         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
 613         if (iov->iov_len < hdrlen) {
 614                 dprintk("NFS: READLINK reply header overflowed:"
 615                                 "length %Zu > %Zu\n", hdrlen, iov->iov_len);
 616                 return -errno_NFSERR_IO;
 617         } else if (iov->iov_len != hdrlen) {
 618                 dprintk("NFS: READLINK header is short. iovec will be shifted.\n");
 619                 xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
 620         }
 621         recvd = req->rq_rcv_buf.len - hdrlen;
 622         if (recvd < len) {
 623                 dprintk("NFS: server cheating in readlink reply: "
 624                                 "count %u > recvd %u\n", len, recvd);
 625                 return -EIO;
 626         }
 627
 628         /* NULL terminate the string we got */
 629         kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
 630         kaddr[len+rcvbuf->page_base] = '\0';
 631         kunmap_atomic(kaddr, KM_USER0);
 632         return 0;
 633 }
 634
 635 /*
 636  * Decode WRITE reply
 637  */
 638 static int
 639 nfs_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
 640 {
 641         res->verf->committed = NFS_FILE_SYNC;
 642         return nfs_xdr_attrstat(req, p, res->fattr);
 643 }
 644
 645 /*
 646  * Decode STATFS reply
 647  */
 648 static int
 649 nfs_xdr_statfsres(struct rpc_rqst *req, __be32 *p, struct nfs2_fsstat *res)
 650 {
 651         int     status;
 652
 653         if ((status = ntohl(*p++)))
 654                 return nfs_stat_to_errno(status);
 655
 656         res->tsize  = ntohl(*p++);
 657         res->bsize  = ntohl(*p++);
 658         res->blocks = ntohl(*p++);
 659         res->bfree  = ntohl(*p++);
 660         res->bavail = ntohl(*p++);
 661         return 0;
 662 }
 663
 664 /*
 665  * We need to translate between nfs status return values and
 666  * the local errno values which may not be the same.
 667  */
 668 static struct {
 669         int stat;
 670         int errno;
 671 } nfs_errtbl[] = {
 672         { NFS_OK,               0               },
 673         { NFSERR_PERM,          -EPERM          },
 674         { NFSERR_NOENT,         -ENOENT         },
 675         { NFSERR_IO,            -errno_NFSERR_IO},
 676         { NFSERR_NXIO,          -ENXIO          },
 677 /*      { NFSERR_EAGAIN,        -EAGAIN         }, */
 678         { NFSERR_ACCES,         -EACCES         },
 679         { NFSERR_EXIST,         -EEXIST         },
 680         { NFSERR_XDEV,          -EXDEV          },
 681         { NFSERR_NODEV,         -ENODEV         },
 682         { NFSERR_NOTDIR,        -ENOTDIR        },
 683         { NFSERR_ISDIR,         -EISDIR         },
 684         { NFSERR_INVAL,         -EINVAL         },
 685         { NFSERR_FBIG,          -EFBIG          },
 686         { NFSERR_NOSPC,         -ENOSPC         },
 687         { NFSERR_ROFS,          -EROFS          },
 688         { NFSERR_MLINK,         -EMLINK         },
 689         { NFSERR_NAMETOOLONG,   -ENAMETOOLONG   },
 690         { NFSERR_NOTEMPTY,      -ENOTEMPTY      },
 691         { NFSERR_DQUOT,         -EDQUOT         },
 692         { NFSERR_STALE,         -ESTALE         },
 693         { NFSERR_REMOTE,        -EREMOTE        },
 694 #ifdef EWFLUSH
 695         { NFSERR_WFLUSH,        -EWFLUSH        },
 696 #endif
 697         { NFSERR_BADHANDLE,     -EBADHANDLE     },
 698         { NFSERR_NOT_SYNC,      -ENOTSYNC       },
 699         { NFSERR_BAD_COOKIE,    -EBADCOOKIE     },
 700         { NFSERR_NOTSUPP,       -ENOTSUPP       },
 701         { NFSERR_TOOSMALL,      -ETOOSMALL      },
 702         { NFSERR_SERVERFAULT,   -ESERVERFAULT   },
 703         { NFSERR_BADTYPE,       -EBADTYPE       },
 704         { NFSERR_JUKEBOX,       -EJUKEBOX       },
 705         { -1,                   -EIO            }
 706 };
 707
 708 /*
 709  * Convert an NFS error code to a local one.
 710  * This one is used jointly by NFSv2 and NFSv3.
 711  */
 712 int
 713 nfs_stat_to_errno(int stat)
 714 {
 715         int i;
 716
 717         for (i = 0; nfs_errtbl[i].stat != -1; i++) {
 718                 if (nfs_errtbl[i].stat == stat)
 719                         return nfs_errtbl[i].errno;
 720         }
 721         dprintk("nfs_stat_to_errno: bad nfs status return value: %d\n", stat);
 722         return nfs_errtbl[i].errno;
 723 }
 724
 725 #define PROC(proc, argtype, restype, timer)                             \
 726 [NFSPROC_##proc] = {                                                    \
 727         .p_proc     =  NFSPROC_##proc,                                  \
 728         .p_encode   =  (kxdrproc_t) nfs_xdr_##argtype,                  \
 729         .p_decode   =  (kxdrproc_t) nfs_xdr_##restype,                  \
 730         .p_arglen   =  NFS_##argtype##_sz,                              \
 731         .p_replen   =  NFS_##restype##_sz,                              \
 732         .p_timer    =  timer,                                           \
 733         .p_statidx  =  NFSPROC_##proc,                                  \
 734         .p_name     =  #proc,                                           \
 735         }
 736 struct rpc_procinfo     nfs_procedures[] = {
 737     PROC(GETATTR,       fhandle,        attrstat, 1),
 738     PROC(SETATTR,       sattrargs,      attrstat, 0),
 739     PROC(LOOKUP,        diropargs,      diropres, 2),
 740     PROC(READLINK,      readlinkargs,   readlinkres, 3),
 741     PROC(READ,          readargs,       readres, 3),
 742     PROC(WRITE,         writeargs,      writeres, 4),
 743     PROC(CREATE,        createargs,     diropres, 0),
 744     PROC(REMOVE,        removeargs,     stat, 0),
 745     PROC(RENAME,        renameargs,     stat, 0),
 746     PROC(LINK,          linkargs,       stat, 0),
 747     PROC(SYMLINK,       symlinkargs,    stat, 0),
 748     PROC(MKDIR,         createargs,     diropres, 0),
 749     PROC(RMDIR,         diropargs,      stat, 0),
 750     PROC(READDIR,       readdirargs,    readdirres, 3),
 751     PROC(STATFS,        fhandle,        statfsres, 0),
 752 };
 753
 754 struct rpc_version              nfs_version2 = {
 755         .number                 = 2,
 756         .nrprocs                = ARRAY_SIZE(nfs_procedures),
 757         .procs                  = nfs_procedures
 758 };