xref: /openbmc/linux/fs/nfs/nfs2xdr.c (revision a17c2153)
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/errno.h>
16 #include <linux/string.h>
17 #include <linux/in.h>
18 #include <linux/pagemap.h>
19 #include <linux/proc_fs.h>
20 #include <linux/sunrpc/clnt.h>
21 #include <linux/nfs.h>
22 #include <linux/nfs2.h>
23 #include <linux/nfs_fs.h>
24 #include "internal.h"
25 
26 #define NFSDBG_FACILITY		NFSDBG_XDR
27 
28 /* Mapping from NFS error code to "errno" error code. */
29 #define errno_NFSERR_IO		EIO
30 
31 /*
32  * Declare the space requirements for NFS arguments and replies as
33  * number of 32bit-words
34  */
35 #define NFS_fhandle_sz		(8)
36 #define NFS_sattr_sz		(8)
37 #define NFS_filename_sz		(1+(NFS2_MAXNAMLEN>>2))
38 #define NFS_path_sz		(1+(NFS2_MAXPATHLEN>>2))
39 #define NFS_fattr_sz		(17)
40 #define NFS_info_sz		(5)
41 #define NFS_entry_sz		(NFS_filename_sz+3)
42 
43 #define NFS_diropargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
44 #define NFS_removeargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
45 #define NFS_sattrargs_sz	(NFS_fhandle_sz+NFS_sattr_sz)
46 #define NFS_readlinkargs_sz	(NFS_fhandle_sz)
47 #define NFS_readargs_sz		(NFS_fhandle_sz+3)
48 #define NFS_writeargs_sz	(NFS_fhandle_sz+4)
49 #define NFS_createargs_sz	(NFS_diropargs_sz+NFS_sattr_sz)
50 #define NFS_renameargs_sz	(NFS_diropargs_sz+NFS_diropargs_sz)
51 #define NFS_linkargs_sz		(NFS_fhandle_sz+NFS_diropargs_sz)
52 #define NFS_symlinkargs_sz	(NFS_diropargs_sz+1+NFS_sattr_sz)
53 #define NFS_readdirargs_sz	(NFS_fhandle_sz+2)
54 
55 #define NFS_attrstat_sz		(1+NFS_fattr_sz)
56 #define NFS_diropres_sz		(1+NFS_fhandle_sz+NFS_fattr_sz)
57 #define NFS_readlinkres_sz	(2)
58 #define NFS_readres_sz		(1+NFS_fattr_sz+1)
59 #define NFS_writeres_sz         (NFS_attrstat_sz)
60 #define NFS_stat_sz		(1)
61 #define NFS_readdirres_sz	(1)
62 #define NFS_statfsres_sz	(1+NFS_info_sz)
63 
64 /*
65  * Common NFS XDR functions as inlines
66  */
67 static inline __be32 *
68 xdr_encode_fhandle(__be32 *p, const struct nfs_fh *fhandle)
69 {
70 	memcpy(p, fhandle->data, NFS2_FHSIZE);
71 	return p + XDR_QUADLEN(NFS2_FHSIZE);
72 }
73 
74 static inline __be32 *
75 xdr_decode_fhandle(__be32 *p, struct nfs_fh *fhandle)
76 {
77 	/* NFSv2 handles have a fixed length */
78 	fhandle->size = NFS2_FHSIZE;
79 	memcpy(fhandle->data, p, NFS2_FHSIZE);
80 	return p + XDR_QUADLEN(NFS2_FHSIZE);
81 }
82 
83 static inline __be32*
84 xdr_encode_time(__be32 *p, struct timespec *timep)
85 {
86 	*p++ = htonl(timep->tv_sec);
87 	/* Convert nanoseconds into microseconds */
88 	*p++ = htonl(timep->tv_nsec ? timep->tv_nsec / 1000 : 0);
89 	return p;
90 }
91 
92 static inline __be32*
93 xdr_encode_current_server_time(__be32 *p, struct timespec *timep)
94 {
95 	/*
96 	 * Passing the invalid value useconds=1000000 is a
97 	 * Sun convention for "set to current server time".
98 	 * It's needed to make permissions checks for the
99 	 * "touch" program across v2 mounts to Solaris and
100 	 * Irix boxes work correctly. See description of
101 	 * sattr in section 6.1 of "NFS Illustrated" by
102 	 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
103 	 */
104 	*p++ = htonl(timep->tv_sec);
105 	*p++ = htonl(1000000);
106 	return p;
107 }
108 
109 static inline __be32*
110 xdr_decode_time(__be32 *p, struct timespec *timep)
111 {
112 	timep->tv_sec = ntohl(*p++);
113 	/* Convert microseconds into nanoseconds */
114 	timep->tv_nsec = ntohl(*p++) * 1000;
115 	return p;
116 }
117 
118 static __be32 *
119 xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr)
120 {
121 	u32 rdev, type;
122 	type = ntohl(*p++);
123 	fattr->mode = ntohl(*p++);
124 	fattr->nlink = ntohl(*p++);
125 	fattr->uid = ntohl(*p++);
126 	fattr->gid = ntohl(*p++);
127 	fattr->size = ntohl(*p++);
128 	fattr->du.nfs2.blocksize = ntohl(*p++);
129 	rdev = ntohl(*p++);
130 	fattr->du.nfs2.blocks = ntohl(*p++);
131 	fattr->fsid.major = ntohl(*p++);
132 	fattr->fsid.minor = 0;
133 	fattr->fileid = ntohl(*p++);
134 	p = xdr_decode_time(p, &fattr->atime);
135 	p = xdr_decode_time(p, &fattr->mtime);
136 	p = xdr_decode_time(p, &fattr->ctime);
137 	fattr->valid |= NFS_ATTR_FATTR_V2;
138 	fattr->rdev = new_decode_dev(rdev);
139 	if (type == NFCHR && rdev == NFS2_FIFO_DEV) {
140 		fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
141 		fattr->rdev = 0;
142 	}
143 	return p;
144 }
145 
146 static inline __be32 *
147 xdr_encode_sattr(__be32 *p, struct iattr *attr)
148 {
149 	const __be32 not_set = __constant_htonl(0xFFFFFFFF);
150 
151 	*p++ = (attr->ia_valid & ATTR_MODE) ? htonl(attr->ia_mode) : not_set;
152 	*p++ = (attr->ia_valid & ATTR_UID) ? htonl(attr->ia_uid) : not_set;
153 	*p++ = (attr->ia_valid & ATTR_GID) ? htonl(attr->ia_gid) : not_set;
154 	*p++ = (attr->ia_valid & ATTR_SIZE) ? htonl(attr->ia_size) : not_set;
155 
156 	if (attr->ia_valid & ATTR_ATIME_SET) {
157 		p = xdr_encode_time(p, &attr->ia_atime);
158 	} else if (attr->ia_valid & ATTR_ATIME) {
159 		p = xdr_encode_current_server_time(p, &attr->ia_atime);
160 	} else {
161 		*p++ = not_set;
162 		*p++ = not_set;
163 	}
164 
165 	if (attr->ia_valid & ATTR_MTIME_SET) {
166 		p = xdr_encode_time(p, &attr->ia_mtime);
167 	} else if (attr->ia_valid & ATTR_MTIME) {
168 		p = xdr_encode_current_server_time(p, &attr->ia_mtime);
169 	} else {
170 		*p++ = not_set;
171 		*p++ = not_set;
172 	}
173   	return p;
174 }
175 
176 /*
177  * NFS encode functions
178  */
179 /*
180  * Encode file handle argument
181  * GETATTR, READLINK, STATFS
182  */
183 static int
184 nfs_xdr_fhandle(struct rpc_rqst *req, __be32 *p, struct nfs_fh *fh)
185 {
186 	p = xdr_encode_fhandle(p, fh);
187 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
188 	return 0;
189 }
190 
191 /*
192  * Encode SETATTR arguments
193  */
194 static int
195 nfs_xdr_sattrargs(struct rpc_rqst *req, __be32 *p, struct nfs_sattrargs *args)
196 {
197 	p = xdr_encode_fhandle(p, args->fh);
198 	p = xdr_encode_sattr(p, args->sattr);
199 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
200 	return 0;
201 }
202 
203 /*
204  * Encode directory ops argument
205  * LOOKUP, RMDIR
206  */
207 static int
208 nfs_xdr_diropargs(struct rpc_rqst *req, __be32 *p, struct nfs_diropargs *args)
209 {
210 	p = xdr_encode_fhandle(p, args->fh);
211 	p = xdr_encode_array(p, args->name, args->len);
212 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
213 	return 0;
214 }
215 
216 /*
217  * Encode REMOVE argument
218  */
219 static int
220 nfs_xdr_removeargs(struct rpc_rqst *req, __be32 *p, const struct nfs_removeargs *args)
221 {
222 	p = xdr_encode_fhandle(p, args->fh);
223 	p = xdr_encode_array(p, args->name.name, args->name.len);
224 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
225 	return 0;
226 }
227 
228 /*
229  * Arguments to a READ call. Since we read data directly into the page
230  * cache, we also set up the reply iovec here so that iov[1] points
231  * exactly to the page we want to fetch.
232  */
233 static int
234 nfs_xdr_readargs(struct rpc_rqst *req, __be32 *p, struct nfs_readargs *args)
235 {
236 	struct rpc_auth	*auth = req->rq_cred->cr_auth;
237 	unsigned int replen;
238 	u32 offset = (u32)args->offset;
239 	u32 count = args->count;
240 
241 	p = xdr_encode_fhandle(p, args->fh);
242 	*p++ = htonl(offset);
243 	*p++ = htonl(count);
244 	*p++ = htonl(count);
245 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
246 
247 	/* Inline the page array */
248 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readres_sz) << 2;
249 	xdr_inline_pages(&req->rq_rcv_buf, replen,
250 			 args->pages, args->pgbase, count);
251 	req->rq_rcv_buf.flags |= XDRBUF_READ;
252 	return 0;
253 }
254 
255 /*
256  * Decode READ reply
257  */
258 static int
259 nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
260 {
261 	struct kvec *iov = req->rq_rcv_buf.head;
262 	size_t hdrlen;
263 	u32 count, recvd;
264 	int status;
265 
266 	if ((status = ntohl(*p++)))
267 		return nfs_stat_to_errno(status);
268 	p = xdr_decode_fattr(p, res->fattr);
269 
270 	count = ntohl(*p++);
271 	res->eof = 0;
272 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
273 	if (iov->iov_len < hdrlen) {
274 		dprintk("NFS: READ reply header overflowed:"
275 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
276 		return -errno_NFSERR_IO;
277 	} else if (iov->iov_len != hdrlen) {
278 		dprintk("NFS: READ header is short. iovec will be shifted.\n");
279 		xdr_shift_buf(&req->rq_rcv_buf, iov->iov_len - hdrlen);
280 	}
281 
282 	recvd = req->rq_rcv_buf.len - hdrlen;
283 	if (count > recvd) {
284 		dprintk("NFS: server cheating in read reply: "
285 			"count %u > recvd %u\n", count, recvd);
286 		count = recvd;
287 	}
288 
289 	dprintk("RPC:      readres OK count %u\n", count);
290 	if (count < res->count)
291 		res->count = count;
292 
293 	return count;
294 }
295 
296 
297 /*
298  * Write arguments. Splice the buffer to be written into the iovec.
299  */
300 static int
301 nfs_xdr_writeargs(struct rpc_rqst *req, __be32 *p, struct nfs_writeargs *args)
302 {
303 	struct xdr_buf *sndbuf = &req->rq_snd_buf;
304 	u32 offset = (u32)args->offset;
305 	u32 count = args->count;
306 
307 	p = xdr_encode_fhandle(p, args->fh);
308 	*p++ = htonl(offset);
309 	*p++ = htonl(offset);
310 	*p++ = htonl(count);
311 	*p++ = htonl(count);
312 	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
313 
314 	/* Copy the page array */
315 	xdr_encode_pages(sndbuf, args->pages, args->pgbase, count);
316 	sndbuf->flags |= XDRBUF_WRITE;
317 	return 0;
318 }
319 
320 /*
321  * Encode create arguments
322  * CREATE, MKDIR
323  */
324 static int
325 nfs_xdr_createargs(struct rpc_rqst *req, __be32 *p, struct nfs_createargs *args)
326 {
327 	p = xdr_encode_fhandle(p, args->fh);
328 	p = xdr_encode_array(p, args->name, args->len);
329 	p = xdr_encode_sattr(p, args->sattr);
330 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
331 	return 0;
332 }
333 
334 /*
335  * Encode RENAME arguments
336  */
337 static int
338 nfs_xdr_renameargs(struct rpc_rqst *req, __be32 *p, struct nfs_renameargs *args)
339 {
340 	p = xdr_encode_fhandle(p, args->fromfh);
341 	p = xdr_encode_array(p, args->fromname, args->fromlen);
342 	p = xdr_encode_fhandle(p, args->tofh);
343 	p = xdr_encode_array(p, args->toname, args->tolen);
344 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
345 	return 0;
346 }
347 
348 /*
349  * Encode LINK arguments
350  */
351 static int
352 nfs_xdr_linkargs(struct rpc_rqst *req, __be32 *p, struct nfs_linkargs *args)
353 {
354 	p = xdr_encode_fhandle(p, args->fromfh);
355 	p = xdr_encode_fhandle(p, args->tofh);
356 	p = xdr_encode_array(p, args->toname, args->tolen);
357 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
358 	return 0;
359 }
360 
361 /*
362  * Encode SYMLINK arguments
363  */
364 static int
365 nfs_xdr_symlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_symlinkargs *args)
366 {
367 	struct xdr_buf *sndbuf = &req->rq_snd_buf;
368 	size_t pad;
369 
370 	p = xdr_encode_fhandle(p, args->fromfh);
371 	p = xdr_encode_array(p, args->fromname, args->fromlen);
372 	*p++ = htonl(args->pathlen);
373 	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
374 
375 	xdr_encode_pages(sndbuf, args->pages, 0, args->pathlen);
376 
377 	/*
378 	 * xdr_encode_pages may have added a few bytes to ensure the
379 	 * pathname ends on a 4-byte boundary.  Start encoding the
380 	 * attributes after the pad bytes.
381 	 */
382 	pad = sndbuf->tail->iov_len;
383 	if (pad > 0)
384 		p++;
385 	p = xdr_encode_sattr(p, args->sattr);
386 	sndbuf->len += xdr_adjust_iovec(sndbuf->tail, p) - pad;
387 	return 0;
388 }
389 
390 /*
391  * Encode arguments to readdir call
392  */
393 static int
394 nfs_xdr_readdirargs(struct rpc_rqst *req, __be32 *p, struct nfs_readdirargs *args)
395 {
396 	struct rpc_auth	*auth = req->rq_cred->cr_auth;
397 	unsigned int replen;
398 	u32 count = args->count;
399 
400 	p = xdr_encode_fhandle(p, args->fh);
401 	*p++ = htonl(args->cookie);
402 	*p++ = htonl(count); /* see above */
403 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
404 
405 	/* Inline the page array */
406 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readdirres_sz) << 2;
407 	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, 0, count);
408 	return 0;
409 }
410 
411 /*
412  * Decode the result of a readdir call.
413  * We're not really decoding anymore, we just leave the buffer untouched
414  * and only check that it is syntactically correct.
415  * The real decoding happens in nfs_decode_entry below, called directly
416  * from nfs_readdir for each entry.
417  */
418 static int
419 nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
420 {
421 	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
422 	struct kvec *iov = rcvbuf->head;
423 	struct page **page;
424 	size_t hdrlen;
425 	unsigned int pglen, recvd;
426 	u32 len;
427 	int status, nr = 0;
428 	__be32 *end, *entry, *kaddr;
429 
430 	if ((status = ntohl(*p++)))
431 		return nfs_stat_to_errno(status);
432 
433 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
434 	if (iov->iov_len < hdrlen) {
435 		dprintk("NFS: READDIR reply header overflowed:"
436 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
437 		return -errno_NFSERR_IO;
438 	} else if (iov->iov_len != hdrlen) {
439 		dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
440 		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
441 	}
442 
443 	pglen = rcvbuf->page_len;
444 	recvd = rcvbuf->len - hdrlen;
445 	if (pglen > recvd)
446 		pglen = recvd;
447 	page = rcvbuf->pages;
448 	kaddr = p = kmap_atomic(*page, KM_USER0);
449 	end = (__be32 *)((char *)p + pglen);
450 	entry = p;
451 
452 	/* Make sure the packet actually has a value_follows and EOF entry */
453 	if ((entry + 1) > end)
454 		goto short_pkt;
455 
456 	for (; *p++; nr++) {
457 		if (p + 2 > end)
458 			goto short_pkt;
459 		p++; /* fileid */
460 		len = ntohl(*p++);
461 		p += XDR_QUADLEN(len) + 1;	/* name plus cookie */
462 		if (len > NFS2_MAXNAMLEN) {
463 			dprintk("NFS: giant filename in readdir (len 0x%x)!\n",
464 						len);
465 			goto err_unmap;
466 		}
467 		if (p + 2 > end)
468 			goto short_pkt;
469 		entry = p;
470 	}
471 
472 	/*
473 	 * Apparently some server sends responses that are a valid size, but
474 	 * contain no entries, and have value_follows==0 and EOF==0. For
475 	 * those, just set the EOF marker.
476 	 */
477 	if (!nr && entry[1] == 0) {
478 		dprintk("NFS: readdir reply truncated!\n");
479 		entry[1] = 1;
480 	}
481  out:
482 	kunmap_atomic(kaddr, KM_USER0);
483 	return nr;
484  short_pkt:
485 	/*
486 	 * When we get a short packet there are 2 possibilities. We can
487 	 * return an error, or fix up the response to look like a valid
488 	 * response and return what we have so far. If there are no
489 	 * entries and the packet was short, then return -EIO. If there
490 	 * are valid entries in the response, return them and pretend that
491 	 * the call was successful, but incomplete. The caller can retry the
492 	 * readdir starting at the last cookie.
493 	 */
494 	entry[0] = entry[1] = 0;
495 	if (!nr)
496 		nr = -errno_NFSERR_IO;
497 	goto out;
498 err_unmap:
499 	nr = -errno_NFSERR_IO;
500 	goto out;
501 }
502 
503 __be32 *
504 nfs_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus)
505 {
506 	if (!*p++) {
507 		if (!*p)
508 			return ERR_PTR(-EAGAIN);
509 		entry->eof = 1;
510 		return ERR_PTR(-EBADCOOKIE);
511 	}
512 
513 	entry->ino	  = ntohl(*p++);
514 	entry->len	  = ntohl(*p++);
515 	entry->name	  = (const char *) p;
516 	p		 += XDR_QUADLEN(entry->len);
517 	entry->prev_cookie	  = entry->cookie;
518 	entry->cookie	  = ntohl(*p++);
519 	entry->eof	  = !p[0] && p[1];
520 
521 	return p;
522 }
523 
524 /*
525  * NFS XDR decode functions
526  */
527 /*
528  * Decode simple status reply
529  */
530 static int
531 nfs_xdr_stat(struct rpc_rqst *req, __be32 *p, void *dummy)
532 {
533 	int	status;
534 
535 	if ((status = ntohl(*p++)) != 0)
536 		status = nfs_stat_to_errno(status);
537 	return status;
538 }
539 
540 /*
541  * Decode attrstat reply
542  * GETATTR, SETATTR, WRITE
543  */
544 static int
545 nfs_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
546 {
547 	int	status;
548 
549 	if ((status = ntohl(*p++)))
550 		return nfs_stat_to_errno(status);
551 	xdr_decode_fattr(p, fattr);
552 	return 0;
553 }
554 
555 /*
556  * Decode diropres reply
557  * LOOKUP, CREATE, MKDIR
558  */
559 static int
560 nfs_xdr_diropres(struct rpc_rqst *req, __be32 *p, struct nfs_diropok *res)
561 {
562 	int	status;
563 
564 	if ((status = ntohl(*p++)))
565 		return nfs_stat_to_errno(status);
566 	p = xdr_decode_fhandle(p, res->fh);
567 	xdr_decode_fattr(p, res->fattr);
568 	return 0;
569 }
570 
571 /*
572  * Encode READLINK args
573  */
574 static int
575 nfs_xdr_readlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_readlinkargs *args)
576 {
577 	struct rpc_auth	*auth = req->rq_cred->cr_auth;
578 	unsigned int replen;
579 
580 	p = xdr_encode_fhandle(p, args->fh);
581 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
582 
583 	/* Inline the page array */
584 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readlinkres_sz) << 2;
585 	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, args->pgbase, args->pglen);
586 	return 0;
587 }
588 
589 /*
590  * Decode READLINK reply
591  */
592 static int
593 nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
594 {
595 	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
596 	struct kvec *iov = rcvbuf->head;
597 	size_t hdrlen;
598 	u32 len, recvd;
599 	char	*kaddr;
600 	int	status;
601 
602 	if ((status = ntohl(*p++)))
603 		return nfs_stat_to_errno(status);
604 	/* Convert length of symlink */
605 	len = ntohl(*p++);
606 	if (len >= rcvbuf->page_len) {
607 		dprintk("nfs: server returned giant symlink!\n");
608 		return -ENAMETOOLONG;
609 	}
610 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
611 	if (iov->iov_len < hdrlen) {
612 		dprintk("NFS: READLINK reply header overflowed:"
613 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
614 		return -errno_NFSERR_IO;
615 	} else if (iov->iov_len != hdrlen) {
616 		dprintk("NFS: READLINK header is short. iovec will be shifted.\n");
617 		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
618 	}
619 	recvd = req->rq_rcv_buf.len - hdrlen;
620 	if (recvd < len) {
621 		dprintk("NFS: server cheating in readlink reply: "
622 				"count %u > recvd %u\n", len, recvd);
623 		return -EIO;
624 	}
625 
626 	/* NULL terminate the string we got */
627 	kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
628 	kaddr[len+rcvbuf->page_base] = '\0';
629 	kunmap_atomic(kaddr, KM_USER0);
630 	return 0;
631 }
632 
633 /*
634  * Decode WRITE reply
635  */
636 static int
637 nfs_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
638 {
639 	res->verf->committed = NFS_FILE_SYNC;
640 	return nfs_xdr_attrstat(req, p, res->fattr);
641 }
642 
643 /*
644  * Decode STATFS reply
645  */
646 static int
647 nfs_xdr_statfsres(struct rpc_rqst *req, __be32 *p, struct nfs2_fsstat *res)
648 {
649 	int	status;
650 
651 	if ((status = ntohl(*p++)))
652 		return nfs_stat_to_errno(status);
653 
654 	res->tsize  = ntohl(*p++);
655 	res->bsize  = ntohl(*p++);
656 	res->blocks = ntohl(*p++);
657 	res->bfree  = ntohl(*p++);
658 	res->bavail = ntohl(*p++);
659 	return 0;
660 }
661 
662 /*
663  * We need to translate between nfs status return values and
664  * the local errno values which may not be the same.
665  */
666 static struct {
667 	int stat;
668 	int errno;
669 } nfs_errtbl[] = {
670 	{ NFS_OK,		0		},
671 	{ NFSERR_PERM,		-EPERM		},
672 	{ NFSERR_NOENT,		-ENOENT		},
673 	{ NFSERR_IO,		-errno_NFSERR_IO},
674 	{ NFSERR_NXIO,		-ENXIO		},
675 /*	{ NFSERR_EAGAIN,	-EAGAIN		}, */
676 	{ NFSERR_ACCES,		-EACCES		},
677 	{ NFSERR_EXIST,		-EEXIST		},
678 	{ NFSERR_XDEV,		-EXDEV		},
679 	{ NFSERR_NODEV,		-ENODEV		},
680 	{ NFSERR_NOTDIR,	-ENOTDIR	},
681 	{ NFSERR_ISDIR,		-EISDIR		},
682 	{ NFSERR_INVAL,		-EINVAL		},
683 	{ NFSERR_FBIG,		-EFBIG		},
684 	{ NFSERR_NOSPC,		-ENOSPC		},
685 	{ NFSERR_ROFS,		-EROFS		},
686 	{ NFSERR_MLINK,		-EMLINK		},
687 	{ NFSERR_NAMETOOLONG,	-ENAMETOOLONG	},
688 	{ NFSERR_NOTEMPTY,	-ENOTEMPTY	},
689 	{ NFSERR_DQUOT,		-EDQUOT		},
690 	{ NFSERR_STALE,		-ESTALE		},
691 	{ NFSERR_REMOTE,	-EREMOTE	},
692 #ifdef EWFLUSH
693 	{ NFSERR_WFLUSH,	-EWFLUSH	},
694 #endif
695 	{ NFSERR_BADHANDLE,	-EBADHANDLE	},
696 	{ NFSERR_NOT_SYNC,	-ENOTSYNC	},
697 	{ NFSERR_BAD_COOKIE,	-EBADCOOKIE	},
698 	{ NFSERR_NOTSUPP,	-ENOTSUPP	},
699 	{ NFSERR_TOOSMALL,	-ETOOSMALL	},
700 	{ NFSERR_SERVERFAULT,	-EREMOTEIO	},
701 	{ NFSERR_BADTYPE,	-EBADTYPE	},
702 	{ NFSERR_JUKEBOX,	-EJUKEBOX	},
703 	{ -1,			-EIO		}
704 };
705 
706 /*
707  * Convert an NFS error code to a local one.
708  * This one is used jointly by NFSv2 and NFSv3.
709  */
710 int
711 nfs_stat_to_errno(int stat)
712 {
713 	int i;
714 
715 	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
716 		if (nfs_errtbl[i].stat == stat)
717 			return nfs_errtbl[i].errno;
718 	}
719 	dprintk("nfs_stat_to_errno: bad nfs status return value: %d\n", stat);
720 	return nfs_errtbl[i].errno;
721 }
722 
723 #define PROC(proc, argtype, restype, timer)				\
724 [NFSPROC_##proc] = {							\
725 	.p_proc	    =  NFSPROC_##proc,					\
726 	.p_encode   =  (kxdrproc_t) nfs_xdr_##argtype,			\
727 	.p_decode   =  (kxdrproc_t) nfs_xdr_##restype,			\
728 	.p_arglen   =  NFS_##argtype##_sz,				\
729 	.p_replen   =  NFS_##restype##_sz,				\
730 	.p_timer    =  timer,						\
731 	.p_statidx  =  NFSPROC_##proc,					\
732 	.p_name     =  #proc,						\
733 	}
734 struct rpc_procinfo	nfs_procedures[] = {
735     PROC(GETATTR,	fhandle,	attrstat, 1),
736     PROC(SETATTR,	sattrargs,	attrstat, 0),
737     PROC(LOOKUP,	diropargs,	diropres, 2),
738     PROC(READLINK,	readlinkargs,	readlinkres, 3),
739     PROC(READ,		readargs,	readres, 3),
740     PROC(WRITE,		writeargs,	writeres, 4),
741     PROC(CREATE,	createargs,	diropres, 0),
742     PROC(REMOVE,	removeargs,	stat, 0),
743     PROC(RENAME,	renameargs,	stat, 0),
744     PROC(LINK,		linkargs,	stat, 0),
745     PROC(SYMLINK,	symlinkargs,	stat, 0),
746     PROC(MKDIR,		createargs,	diropres, 0),
747     PROC(RMDIR,		diropargs,	stat, 0),
748     PROC(READDIR,	readdirargs,	readdirres, 3),
749     PROC(STATFS,	fhandle,	statfsres, 0),
750 };
751 
752 struct rpc_version		nfs_version2 = {
753 	.number			= 2,
754 	.nrprocs		= ARRAY_SIZE(nfs_procedures),
755 	.procs			= nfs_procedures
756 };
757