xref: /openbmc/linux/fs/nfs/nfs2xdr.c (revision 7211ec63)
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 static int nfs_stat_to_errno(enum nfs_stat);
65 
66 /*
67  * While encoding arguments, set up the reply buffer in advance to
68  * receive reply data directly into the page cache.
69  */
70 static void prepare_reply_buffer(struct rpc_rqst *req, struct page **pages,
71 				 unsigned int base, unsigned int len,
72 				 unsigned int bufsize)
73 {
74 	struct rpc_auth	*auth = req->rq_cred->cr_auth;
75 	unsigned int replen;
76 
77 	replen = RPC_REPHDRSIZE + auth->au_rslack + bufsize;
78 	xdr_inline_pages(&req->rq_rcv_buf, replen << 2, pages, base, len);
79 }
80 
81 /*
82  * Handle decode buffer overflows out-of-line.
83  */
84 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
85 {
86 	dprintk("NFS: %s prematurely hit the end of our receive buffer. "
87 		"Remaining buffer length is %tu words.\n",
88 		func, xdr->end - xdr->p);
89 }
90 
91 
92 /*
93  * Encode/decode NFSv2 basic data types
94  *
95  * Basic NFSv2 data types are defined in section 2.3 of RFC 1094:
96  * "NFS: Network File System Protocol Specification".
97  *
98  * Not all basic data types have their own encoding and decoding
99  * functions.  For run-time efficiency, some data types are encoded
100  * or decoded inline.
101  */
102 
103 /*
104  *	typedef opaque	nfsdata<>;
105  */
106 static int decode_nfsdata(struct xdr_stream *xdr, struct nfs_pgio_res *result)
107 {
108 	u32 recvd, count;
109 	__be32 *p;
110 
111 	p = xdr_inline_decode(xdr, 4);
112 	if (unlikely(p == NULL))
113 		goto out_overflow;
114 	count = be32_to_cpup(p);
115 	recvd = xdr_read_pages(xdr, count);
116 	if (unlikely(count > recvd))
117 		goto out_cheating;
118 out:
119 	result->eof = 0;	/* NFSv2 does not pass EOF flag on the wire. */
120 	result->count = count;
121 	return count;
122 out_cheating:
123 	dprintk("NFS: server cheating in read result: "
124 		"count %u > recvd %u\n", count, recvd);
125 	count = recvd;
126 	goto out;
127 out_overflow:
128 	print_overflow_msg(__func__, xdr);
129 	return -EIO;
130 }
131 
132 /*
133  *	enum stat {
134  *		NFS_OK = 0,
135  *		NFSERR_PERM = 1,
136  *		NFSERR_NOENT = 2,
137  *		NFSERR_IO = 5,
138  *		NFSERR_NXIO = 6,
139  *		NFSERR_ACCES = 13,
140  *		NFSERR_EXIST = 17,
141  *		NFSERR_NODEV = 19,
142  *		NFSERR_NOTDIR = 20,
143  *		NFSERR_ISDIR = 21,
144  *		NFSERR_FBIG = 27,
145  *		NFSERR_NOSPC = 28,
146  *		NFSERR_ROFS = 30,
147  *		NFSERR_NAMETOOLONG = 63,
148  *		NFSERR_NOTEMPTY = 66,
149  *		NFSERR_DQUOT = 69,
150  *		NFSERR_STALE = 70,
151  *		NFSERR_WFLUSH = 99
152  *	};
153  */
154 static int decode_stat(struct xdr_stream *xdr, enum nfs_stat *status)
155 {
156 	__be32 *p;
157 
158 	p = xdr_inline_decode(xdr, 4);
159 	if (unlikely(p == NULL))
160 		goto out_overflow;
161 	*status = be32_to_cpup(p);
162 	return 0;
163 out_overflow:
164 	print_overflow_msg(__func__, xdr);
165 	return -EIO;
166 }
167 
168 /*
169  * 2.3.2.  ftype
170  *
171  *	enum ftype {
172  *		NFNON = 0,
173  *		NFREG = 1,
174  *		NFDIR = 2,
175  *		NFBLK = 3,
176  *		NFCHR = 4,
177  *		NFLNK = 5
178  *	};
179  *
180  */
181 static __be32 *xdr_decode_ftype(__be32 *p, u32 *type)
182 {
183 	*type = be32_to_cpup(p++);
184 	if (unlikely(*type > NF2FIFO))
185 		*type = NFBAD;
186 	return p;
187 }
188 
189 /*
190  * 2.3.3.  fhandle
191  *
192  *	typedef opaque fhandle[FHSIZE];
193  */
194 static void encode_fhandle(struct xdr_stream *xdr, const struct nfs_fh *fh)
195 {
196 	__be32 *p;
197 
198 	p = xdr_reserve_space(xdr, NFS2_FHSIZE);
199 	memcpy(p, fh->data, NFS2_FHSIZE);
200 }
201 
202 static int decode_fhandle(struct xdr_stream *xdr, struct nfs_fh *fh)
203 {
204 	__be32 *p;
205 
206 	p = xdr_inline_decode(xdr, NFS2_FHSIZE);
207 	if (unlikely(p == NULL))
208 		goto out_overflow;
209 	fh->size = NFS2_FHSIZE;
210 	memcpy(fh->data, p, NFS2_FHSIZE);
211 	return 0;
212 out_overflow:
213 	print_overflow_msg(__func__, xdr);
214 	return -EIO;
215 }
216 
217 /*
218  * 2.3.4.  timeval
219  *
220  *	struct timeval {
221  *		unsigned int seconds;
222  *		unsigned int useconds;
223  *	};
224  */
225 static __be32 *xdr_encode_time(__be32 *p, const struct timespec *timep)
226 {
227 	*p++ = cpu_to_be32(timep->tv_sec);
228 	if (timep->tv_nsec != 0)
229 		*p++ = cpu_to_be32(timep->tv_nsec / NSEC_PER_USEC);
230 	else
231 		*p++ = cpu_to_be32(0);
232 	return p;
233 }
234 
235 /*
236  * Passing the invalid value useconds=1000000 is a Sun convention for
237  * "set to current server time".  It's needed to make permissions checks
238  * for the "touch" program across v2 mounts to Solaris and Irix servers
239  * work correctly.  See description of sattr in section 6.1 of "NFS
240  * Illustrated" by Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5.
241  */
242 static __be32 *xdr_encode_current_server_time(__be32 *p,
243 					      const struct timespec *timep)
244 {
245 	*p++ = cpu_to_be32(timep->tv_sec);
246 	*p++ = cpu_to_be32(1000000);
247 	return p;
248 }
249 
250 static __be32 *xdr_decode_time(__be32 *p, struct timespec *timep)
251 {
252 	timep->tv_sec = be32_to_cpup(p++);
253 	timep->tv_nsec = be32_to_cpup(p++) * NSEC_PER_USEC;
254 	return p;
255 }
256 
257 /*
258  * 2.3.5.  fattr
259  *
260  *	struct fattr {
261  *		ftype		type;
262  *		unsigned int	mode;
263  *		unsigned int	nlink;
264  *		unsigned int	uid;
265  *		unsigned int	gid;
266  *		unsigned int	size;
267  *		unsigned int	blocksize;
268  *		unsigned int	rdev;
269  *		unsigned int	blocks;
270  *		unsigned int	fsid;
271  *		unsigned int	fileid;
272  *		timeval		atime;
273  *		timeval		mtime;
274  *		timeval		ctime;
275  *	};
276  *
277  */
278 static int decode_fattr(struct xdr_stream *xdr, struct nfs_fattr *fattr)
279 {
280 	u32 rdev, type;
281 	__be32 *p;
282 
283 	p = xdr_inline_decode(xdr, NFS_fattr_sz << 2);
284 	if (unlikely(p == NULL))
285 		goto out_overflow;
286 
287 	fattr->valid |= NFS_ATTR_FATTR_V2;
288 
289 	p = xdr_decode_ftype(p, &type);
290 
291 	fattr->mode = be32_to_cpup(p++);
292 	fattr->nlink = be32_to_cpup(p++);
293 	fattr->uid = make_kuid(&init_user_ns, be32_to_cpup(p++));
294 	if (!uid_valid(fattr->uid))
295 		goto out_uid;
296 	fattr->gid = make_kgid(&init_user_ns, be32_to_cpup(p++));
297 	if (!gid_valid(fattr->gid))
298 		goto out_gid;
299 
300 	fattr->size = be32_to_cpup(p++);
301 	fattr->du.nfs2.blocksize = be32_to_cpup(p++);
302 
303 	rdev = be32_to_cpup(p++);
304 	fattr->rdev = new_decode_dev(rdev);
305 	if (type == (u32)NFCHR && rdev == (u32)NFS2_FIFO_DEV) {
306 		fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
307 		fattr->rdev = 0;
308 	}
309 
310 	fattr->du.nfs2.blocks = be32_to_cpup(p++);
311 	fattr->fsid.major = be32_to_cpup(p++);
312 	fattr->fsid.minor = 0;
313 	fattr->fileid = be32_to_cpup(p++);
314 
315 	p = xdr_decode_time(p, &fattr->atime);
316 	p = xdr_decode_time(p, &fattr->mtime);
317 	xdr_decode_time(p, &fattr->ctime);
318 	fattr->change_attr = nfs_timespec_to_change_attr(&fattr->ctime);
319 
320 	return 0;
321 out_uid:
322 	dprintk("NFS: returned invalid uid\n");
323 	return -EINVAL;
324 out_gid:
325 	dprintk("NFS: returned invalid gid\n");
326 	return -EINVAL;
327 out_overflow:
328 	print_overflow_msg(__func__, xdr);
329 	return -EIO;
330 }
331 
332 /*
333  * 2.3.6.  sattr
334  *
335  *	struct sattr {
336  *		unsigned int	mode;
337  *		unsigned int	uid;
338  *		unsigned int	gid;
339  *		unsigned int	size;
340  *		timeval		atime;
341  *		timeval		mtime;
342  *	};
343  */
344 
345 #define NFS2_SATTR_NOT_SET	(0xffffffff)
346 
347 static __be32 *xdr_time_not_set(__be32 *p)
348 {
349 	*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
350 	*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
351 	return p;
352 }
353 
354 static void encode_sattr(struct xdr_stream *xdr, const struct iattr *attr)
355 {
356 	__be32 *p;
357 
358 	p = xdr_reserve_space(xdr, NFS_sattr_sz << 2);
359 
360 	if (attr->ia_valid & ATTR_MODE)
361 		*p++ = cpu_to_be32(attr->ia_mode);
362 	else
363 		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
364 	if (attr->ia_valid & ATTR_UID)
365 		*p++ = cpu_to_be32(from_kuid(&init_user_ns, attr->ia_uid));
366 	else
367 		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
368 	if (attr->ia_valid & ATTR_GID)
369 		*p++ = cpu_to_be32(from_kgid(&init_user_ns, attr->ia_gid));
370 	else
371 		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
372 	if (attr->ia_valid & ATTR_SIZE)
373 		*p++ = cpu_to_be32((u32)attr->ia_size);
374 	else
375 		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
376 
377 	if (attr->ia_valid & ATTR_ATIME_SET)
378 		p = xdr_encode_time(p, &attr->ia_atime);
379 	else if (attr->ia_valid & ATTR_ATIME)
380 		p = xdr_encode_current_server_time(p, &attr->ia_atime);
381 	else
382 		p = xdr_time_not_set(p);
383 	if (attr->ia_valid & ATTR_MTIME_SET)
384 		xdr_encode_time(p, &attr->ia_mtime);
385 	else if (attr->ia_valid & ATTR_MTIME)
386 		xdr_encode_current_server_time(p, &attr->ia_mtime);
387 	else
388 		xdr_time_not_set(p);
389 }
390 
391 /*
392  * 2.3.7.  filename
393  *
394  *	typedef string filename<MAXNAMLEN>;
395  */
396 static void encode_filename(struct xdr_stream *xdr,
397 			    const char *name, u32 length)
398 {
399 	__be32 *p;
400 
401 	WARN_ON_ONCE(length > NFS2_MAXNAMLEN);
402 	p = xdr_reserve_space(xdr, 4 + length);
403 	xdr_encode_opaque(p, name, length);
404 }
405 
406 static int decode_filename_inline(struct xdr_stream *xdr,
407 				  const char **name, u32 *length)
408 {
409 	__be32 *p;
410 	u32 count;
411 
412 	p = xdr_inline_decode(xdr, 4);
413 	if (unlikely(p == NULL))
414 		goto out_overflow;
415 	count = be32_to_cpup(p);
416 	if (count > NFS3_MAXNAMLEN)
417 		goto out_nametoolong;
418 	p = xdr_inline_decode(xdr, count);
419 	if (unlikely(p == NULL))
420 		goto out_overflow;
421 	*name = (const char *)p;
422 	*length = count;
423 	return 0;
424 out_nametoolong:
425 	dprintk("NFS: returned filename too long: %u\n", count);
426 	return -ENAMETOOLONG;
427 out_overflow:
428 	print_overflow_msg(__func__, xdr);
429 	return -EIO;
430 }
431 
432 /*
433  * 2.3.8.  path
434  *
435  *	typedef string path<MAXPATHLEN>;
436  */
437 static void encode_path(struct xdr_stream *xdr, struct page **pages, u32 length)
438 {
439 	__be32 *p;
440 
441 	p = xdr_reserve_space(xdr, 4);
442 	*p = cpu_to_be32(length);
443 	xdr_write_pages(xdr, pages, 0, length);
444 }
445 
446 static int decode_path(struct xdr_stream *xdr)
447 {
448 	u32 length, recvd;
449 	__be32 *p;
450 
451 	p = xdr_inline_decode(xdr, 4);
452 	if (unlikely(p == NULL))
453 		goto out_overflow;
454 	length = be32_to_cpup(p);
455 	if (unlikely(length >= xdr->buf->page_len || length > NFS_MAXPATHLEN))
456 		goto out_size;
457 	recvd = xdr_read_pages(xdr, length);
458 	if (unlikely(length > recvd))
459 		goto out_cheating;
460 	xdr_terminate_string(xdr->buf, length);
461 	return 0;
462 out_size:
463 	dprintk("NFS: returned pathname too long: %u\n", length);
464 	return -ENAMETOOLONG;
465 out_cheating:
466 	dprintk("NFS: server cheating in pathname result: "
467 		"length %u > received %u\n", length, recvd);
468 	return -EIO;
469 out_overflow:
470 	print_overflow_msg(__func__, xdr);
471 	return -EIO;
472 }
473 
474 /*
475  * 2.3.9.  attrstat
476  *
477  *	union attrstat switch (stat status) {
478  *	case NFS_OK:
479  *		fattr attributes;
480  *	default:
481  *		void;
482  *	};
483  */
484 static int decode_attrstat(struct xdr_stream *xdr, struct nfs_fattr *result,
485 			   __u32 *op_status)
486 {
487 	enum nfs_stat status;
488 	int error;
489 
490 	error = decode_stat(xdr, &status);
491 	if (unlikely(error))
492 		goto out;
493 	if (op_status)
494 		*op_status = status;
495 	if (status != NFS_OK)
496 		goto out_default;
497 	error = decode_fattr(xdr, result);
498 out:
499 	return error;
500 out_default:
501 	return nfs_stat_to_errno(status);
502 }
503 
504 /*
505  * 2.3.10.  diropargs
506  *
507  *	struct diropargs {
508  *		fhandle  dir;
509  *		filename name;
510  *	};
511  */
512 static void encode_diropargs(struct xdr_stream *xdr, const struct nfs_fh *fh,
513 			     const char *name, u32 length)
514 {
515 	encode_fhandle(xdr, fh);
516 	encode_filename(xdr, name, length);
517 }
518 
519 /*
520  * 2.3.11.  diropres
521  *
522  *	union diropres switch (stat status) {
523  *	case NFS_OK:
524  *		struct {
525  *			fhandle file;
526  *			fattr   attributes;
527  *		} diropok;
528  *	default:
529  *		void;
530  *	};
531  */
532 static int decode_diropok(struct xdr_stream *xdr, struct nfs_diropok *result)
533 {
534 	int error;
535 
536 	error = decode_fhandle(xdr, result->fh);
537 	if (unlikely(error))
538 		goto out;
539 	error = decode_fattr(xdr, result->fattr);
540 out:
541 	return error;
542 }
543 
544 static int decode_diropres(struct xdr_stream *xdr, struct nfs_diropok *result)
545 {
546 	enum nfs_stat status;
547 	int error;
548 
549 	error = decode_stat(xdr, &status);
550 	if (unlikely(error))
551 		goto out;
552 	if (status != NFS_OK)
553 		goto out_default;
554 	error = decode_diropok(xdr, result);
555 out:
556 	return error;
557 out_default:
558 	return nfs_stat_to_errno(status);
559 }
560 
561 
562 /*
563  * NFSv2 XDR encode functions
564  *
565  * NFSv2 argument types are defined in section 2.2 of RFC 1094:
566  * "NFS: Network File System Protocol Specification".
567  */
568 
569 static void nfs2_xdr_enc_fhandle(struct rpc_rqst *req,
570 				 struct xdr_stream *xdr,
571 				 const void *data)
572 {
573 	const struct nfs_fh *fh = data;
574 
575 	encode_fhandle(xdr, fh);
576 }
577 
578 /*
579  * 2.2.3.  sattrargs
580  *
581  *	struct sattrargs {
582  *		fhandle file;
583  *		sattr attributes;
584  *	};
585  */
586 static void nfs2_xdr_enc_sattrargs(struct rpc_rqst *req,
587 				   struct xdr_stream *xdr,
588 				   const void *data)
589 {
590 	const struct nfs_sattrargs *args = data;
591 
592 	encode_fhandle(xdr, args->fh);
593 	encode_sattr(xdr, args->sattr);
594 }
595 
596 static void nfs2_xdr_enc_diropargs(struct rpc_rqst *req,
597 				   struct xdr_stream *xdr,
598 				   const void *data)
599 {
600 	const struct nfs_diropargs *args = data;
601 
602 	encode_diropargs(xdr, args->fh, args->name, args->len);
603 }
604 
605 static void nfs2_xdr_enc_readlinkargs(struct rpc_rqst *req,
606 				      struct xdr_stream *xdr,
607 				      const void *data)
608 {
609 	const struct nfs_readlinkargs *args = data;
610 
611 	encode_fhandle(xdr, args->fh);
612 	prepare_reply_buffer(req, args->pages, args->pgbase,
613 					args->pglen, NFS_readlinkres_sz);
614 }
615 
616 /*
617  * 2.2.7.  readargs
618  *
619  *	struct readargs {
620  *		fhandle file;
621  *		unsigned offset;
622  *		unsigned count;
623  *		unsigned totalcount;
624  *	};
625  */
626 static void encode_readargs(struct xdr_stream *xdr,
627 			    const struct nfs_pgio_args *args)
628 {
629 	u32 offset = args->offset;
630 	u32 count = args->count;
631 	__be32 *p;
632 
633 	encode_fhandle(xdr, args->fh);
634 
635 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
636 	*p++ = cpu_to_be32(offset);
637 	*p++ = cpu_to_be32(count);
638 	*p = cpu_to_be32(count);
639 }
640 
641 static void nfs2_xdr_enc_readargs(struct rpc_rqst *req,
642 				  struct xdr_stream *xdr,
643 				  const void *data)
644 {
645 	const struct nfs_pgio_args *args = data;
646 
647 	encode_readargs(xdr, args);
648 	prepare_reply_buffer(req, args->pages, args->pgbase,
649 					args->count, NFS_readres_sz);
650 	req->rq_rcv_buf.flags |= XDRBUF_READ;
651 }
652 
653 /*
654  * 2.2.9.  writeargs
655  *
656  *	struct writeargs {
657  *		fhandle file;
658  *		unsigned beginoffset;
659  *		unsigned offset;
660  *		unsigned totalcount;
661  *		nfsdata data;
662  *	};
663  */
664 static void encode_writeargs(struct xdr_stream *xdr,
665 			     const struct nfs_pgio_args *args)
666 {
667 	u32 offset = args->offset;
668 	u32 count = args->count;
669 	__be32 *p;
670 
671 	encode_fhandle(xdr, args->fh);
672 
673 	p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
674 	*p++ = cpu_to_be32(offset);
675 	*p++ = cpu_to_be32(offset);
676 	*p++ = cpu_to_be32(count);
677 
678 	/* nfsdata */
679 	*p = cpu_to_be32(count);
680 	xdr_write_pages(xdr, args->pages, args->pgbase, count);
681 }
682 
683 static void nfs2_xdr_enc_writeargs(struct rpc_rqst *req,
684 				   struct xdr_stream *xdr,
685 				   const void *data)
686 {
687 	const struct nfs_pgio_args *args = data;
688 
689 	encode_writeargs(xdr, args);
690 	xdr->buf->flags |= XDRBUF_WRITE;
691 }
692 
693 /*
694  * 2.2.10.  createargs
695  *
696  *	struct createargs {
697  *		diropargs where;
698  *		sattr attributes;
699  *	};
700  */
701 static void nfs2_xdr_enc_createargs(struct rpc_rqst *req,
702 				    struct xdr_stream *xdr,
703 				    const void *data)
704 {
705 	const struct nfs_createargs *args = data;
706 
707 	encode_diropargs(xdr, args->fh, args->name, args->len);
708 	encode_sattr(xdr, args->sattr);
709 }
710 
711 static void nfs2_xdr_enc_removeargs(struct rpc_rqst *req,
712 				    struct xdr_stream *xdr,
713 				    const void *data)
714 {
715 	const struct nfs_removeargs *args = data;
716 
717 	encode_diropargs(xdr, args->fh, args->name.name, args->name.len);
718 }
719 
720 /*
721  * 2.2.12.  renameargs
722  *
723  *	struct renameargs {
724  *		diropargs from;
725  *		diropargs to;
726  *	};
727  */
728 static void nfs2_xdr_enc_renameargs(struct rpc_rqst *req,
729 				    struct xdr_stream *xdr,
730 				    const void *data)
731 {
732 	const struct nfs_renameargs *args = data;
733 	const struct qstr *old = args->old_name;
734 	const struct qstr *new = args->new_name;
735 
736 	encode_diropargs(xdr, args->old_dir, old->name, old->len);
737 	encode_diropargs(xdr, args->new_dir, new->name, new->len);
738 }
739 
740 /*
741  * 2.2.13.  linkargs
742  *
743  *	struct linkargs {
744  *		fhandle from;
745  *		diropargs to;
746  *	};
747  */
748 static void nfs2_xdr_enc_linkargs(struct rpc_rqst *req,
749 				  struct xdr_stream *xdr,
750 				  const void *data)
751 {
752 	const struct nfs_linkargs *args = data;
753 
754 	encode_fhandle(xdr, args->fromfh);
755 	encode_diropargs(xdr, args->tofh, args->toname, args->tolen);
756 }
757 
758 /*
759  * 2.2.14.  symlinkargs
760  *
761  *	struct symlinkargs {
762  *		diropargs from;
763  *		path to;
764  *		sattr attributes;
765  *	};
766  */
767 static void nfs2_xdr_enc_symlinkargs(struct rpc_rqst *req,
768 				     struct xdr_stream *xdr,
769 				     const void *data)
770 {
771 	const struct nfs_symlinkargs *args = data;
772 
773 	encode_diropargs(xdr, args->fromfh, args->fromname, args->fromlen);
774 	encode_path(xdr, args->pages, args->pathlen);
775 	encode_sattr(xdr, args->sattr);
776 }
777 
778 /*
779  * 2.2.17.  readdirargs
780  *
781  *	struct readdirargs {
782  *		fhandle dir;
783  *		nfscookie cookie;
784  *		unsigned count;
785  *	};
786  */
787 static void encode_readdirargs(struct xdr_stream *xdr,
788 			       const struct nfs_readdirargs *args)
789 {
790 	__be32 *p;
791 
792 	encode_fhandle(xdr, args->fh);
793 
794 	p = xdr_reserve_space(xdr, 4 + 4);
795 	*p++ = cpu_to_be32(args->cookie);
796 	*p = cpu_to_be32(args->count);
797 }
798 
799 static void nfs2_xdr_enc_readdirargs(struct rpc_rqst *req,
800 				     struct xdr_stream *xdr,
801 				     const void *data)
802 {
803 	const struct nfs_readdirargs *args = data;
804 
805 	encode_readdirargs(xdr, args);
806 	prepare_reply_buffer(req, args->pages, 0,
807 					args->count, NFS_readdirres_sz);
808 }
809 
810 /*
811  * NFSv2 XDR decode functions
812  *
813  * NFSv2 result types are defined in section 2.2 of RFC 1094:
814  * "NFS: Network File System Protocol Specification".
815  */
816 
817 static int nfs2_xdr_dec_stat(struct rpc_rqst *req, struct xdr_stream *xdr,
818 			     void *__unused)
819 {
820 	enum nfs_stat status;
821 	int error;
822 
823 	error = decode_stat(xdr, &status);
824 	if (unlikely(error))
825 		goto out;
826 	if (status != NFS_OK)
827 		goto out_default;
828 out:
829 	return error;
830 out_default:
831 	return nfs_stat_to_errno(status);
832 }
833 
834 static int nfs2_xdr_dec_attrstat(struct rpc_rqst *req, struct xdr_stream *xdr,
835 				 void *result)
836 {
837 	return decode_attrstat(xdr, result, NULL);
838 }
839 
840 static int nfs2_xdr_dec_diropres(struct rpc_rqst *req, struct xdr_stream *xdr,
841 				 void *result)
842 {
843 	return decode_diropres(xdr, result);
844 }
845 
846 /*
847  * 2.2.6.  readlinkres
848  *
849  *	union readlinkres switch (stat status) {
850  *	case NFS_OK:
851  *		path data;
852  *	default:
853  *		void;
854  *	};
855  */
856 static int nfs2_xdr_dec_readlinkres(struct rpc_rqst *req,
857 				    struct xdr_stream *xdr, void *__unused)
858 {
859 	enum nfs_stat status;
860 	int error;
861 
862 	error = decode_stat(xdr, &status);
863 	if (unlikely(error))
864 		goto out;
865 	if (status != NFS_OK)
866 		goto out_default;
867 	error = decode_path(xdr);
868 out:
869 	return error;
870 out_default:
871 	return nfs_stat_to_errno(status);
872 }
873 
874 /*
875  * 2.2.7.  readres
876  *
877  *	union readres switch (stat status) {
878  *	case NFS_OK:
879  *		fattr attributes;
880  *		nfsdata data;
881  *	default:
882  *		void;
883  *	};
884  */
885 static int nfs2_xdr_dec_readres(struct rpc_rqst *req, struct xdr_stream *xdr,
886 				void *data)
887 {
888 	struct nfs_pgio_res *result = data;
889 	enum nfs_stat status;
890 	int error;
891 
892 	error = decode_stat(xdr, &status);
893 	if (unlikely(error))
894 		goto out;
895 	result->op_status = status;
896 	if (status != NFS_OK)
897 		goto out_default;
898 	error = decode_fattr(xdr, result->fattr);
899 	if (unlikely(error))
900 		goto out;
901 	error = decode_nfsdata(xdr, result);
902 out:
903 	return error;
904 out_default:
905 	return nfs_stat_to_errno(status);
906 }
907 
908 static int nfs2_xdr_dec_writeres(struct rpc_rqst *req, struct xdr_stream *xdr,
909 				 void *data)
910 {
911 	struct nfs_pgio_res *result = data;
912 
913 	/* All NFSv2 writes are "file sync" writes */
914 	result->verf->committed = NFS_FILE_SYNC;
915 	return decode_attrstat(xdr, result->fattr, &result->op_status);
916 }
917 
918 /**
919  * nfs2_decode_dirent - Decode a single NFSv2 directory entry stored in
920  *                      the local page cache.
921  * @xdr: XDR stream where entry resides
922  * @entry: buffer to fill in with entry data
923  * @plus: boolean indicating whether this should be a readdirplus entry
924  *
925  * Returns zero if successful, otherwise a negative errno value is
926  * returned.
927  *
928  * This function is not invoked during READDIR reply decoding, but
929  * rather whenever an application invokes the getdents(2) system call
930  * on a directory already in our cache.
931  *
932  * 2.2.17.  entry
933  *
934  *	struct entry {
935  *		unsigned	fileid;
936  *		filename	name;
937  *		nfscookie	cookie;
938  *		entry		*nextentry;
939  *	};
940  */
941 int nfs2_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
942 		       bool plus)
943 {
944 	__be32 *p;
945 	int error;
946 
947 	p = xdr_inline_decode(xdr, 4);
948 	if (unlikely(p == NULL))
949 		goto out_overflow;
950 	if (*p++ == xdr_zero) {
951 		p = xdr_inline_decode(xdr, 4);
952 		if (unlikely(p == NULL))
953 			goto out_overflow;
954 		if (*p++ == xdr_zero)
955 			return -EAGAIN;
956 		entry->eof = 1;
957 		return -EBADCOOKIE;
958 	}
959 
960 	p = xdr_inline_decode(xdr, 4);
961 	if (unlikely(p == NULL))
962 		goto out_overflow;
963 	entry->ino = be32_to_cpup(p);
964 
965 	error = decode_filename_inline(xdr, &entry->name, &entry->len);
966 	if (unlikely(error))
967 		return error;
968 
969 	/*
970 	 * The type (size and byte order) of nfscookie isn't defined in
971 	 * RFC 1094.  This implementation assumes that it's an XDR uint32.
972 	 */
973 	entry->prev_cookie = entry->cookie;
974 	p = xdr_inline_decode(xdr, 4);
975 	if (unlikely(p == NULL))
976 		goto out_overflow;
977 	entry->cookie = be32_to_cpup(p);
978 
979 	entry->d_type = DT_UNKNOWN;
980 
981 	return 0;
982 
983 out_overflow:
984 	print_overflow_msg(__func__, xdr);
985 	return -EAGAIN;
986 }
987 
988 /*
989  * 2.2.17.  readdirres
990  *
991  *	union readdirres switch (stat status) {
992  *	case NFS_OK:
993  *		struct {
994  *			entry *entries;
995  *			bool eof;
996  *		} readdirok;
997  *	default:
998  *		void;
999  *	};
1000  *
1001  * Read the directory contents into the page cache, but don't
1002  * touch them.  The actual decoding is done by nfs2_decode_dirent()
1003  * during subsequent nfs_readdir() calls.
1004  */
1005 static int decode_readdirok(struct xdr_stream *xdr)
1006 {
1007 	return xdr_read_pages(xdr, xdr->buf->page_len);
1008 }
1009 
1010 static int nfs2_xdr_dec_readdirres(struct rpc_rqst *req,
1011 				   struct xdr_stream *xdr, void *__unused)
1012 {
1013 	enum nfs_stat status;
1014 	int error;
1015 
1016 	error = decode_stat(xdr, &status);
1017 	if (unlikely(error))
1018 		goto out;
1019 	if (status != NFS_OK)
1020 		goto out_default;
1021 	error = decode_readdirok(xdr);
1022 out:
1023 	return error;
1024 out_default:
1025 	return nfs_stat_to_errno(status);
1026 }
1027 
1028 /*
1029  * 2.2.18.  statfsres
1030  *
1031  *	union statfsres (stat status) {
1032  *	case NFS_OK:
1033  *		struct {
1034  *			unsigned tsize;
1035  *			unsigned bsize;
1036  *			unsigned blocks;
1037  *			unsigned bfree;
1038  *			unsigned bavail;
1039  *		} info;
1040  *	default:
1041  *		void;
1042  *	};
1043  */
1044 static int decode_info(struct xdr_stream *xdr, struct nfs2_fsstat *result)
1045 {
1046 	__be32 *p;
1047 
1048 	p = xdr_inline_decode(xdr, NFS_info_sz << 2);
1049 	if (unlikely(p == NULL))
1050 		goto out_overflow;
1051 	result->tsize  = be32_to_cpup(p++);
1052 	result->bsize  = be32_to_cpup(p++);
1053 	result->blocks = be32_to_cpup(p++);
1054 	result->bfree  = be32_to_cpup(p++);
1055 	result->bavail = be32_to_cpup(p);
1056 	return 0;
1057 out_overflow:
1058 	print_overflow_msg(__func__, xdr);
1059 	return -EIO;
1060 }
1061 
1062 static int nfs2_xdr_dec_statfsres(struct rpc_rqst *req, struct xdr_stream *xdr,
1063 				  void *result)
1064 {
1065 	enum nfs_stat status;
1066 	int error;
1067 
1068 	error = decode_stat(xdr, &status);
1069 	if (unlikely(error))
1070 		goto out;
1071 	if (status != NFS_OK)
1072 		goto out_default;
1073 	error = decode_info(xdr, result);
1074 out:
1075 	return error;
1076 out_default:
1077 	return nfs_stat_to_errno(status);
1078 }
1079 
1080 
1081 /*
1082  * We need to translate between nfs status return values and
1083  * the local errno values which may not be the same.
1084  */
1085 static const struct {
1086 	int stat;
1087 	int errno;
1088 } nfs_errtbl[] = {
1089 	{ NFS_OK,		0		},
1090 	{ NFSERR_PERM,		-EPERM		},
1091 	{ NFSERR_NOENT,		-ENOENT		},
1092 	{ NFSERR_IO,		-errno_NFSERR_IO},
1093 	{ NFSERR_NXIO,		-ENXIO		},
1094 /*	{ NFSERR_EAGAIN,	-EAGAIN		}, */
1095 	{ NFSERR_ACCES,		-EACCES		},
1096 	{ NFSERR_EXIST,		-EEXIST		},
1097 	{ NFSERR_XDEV,		-EXDEV		},
1098 	{ NFSERR_NODEV,		-ENODEV		},
1099 	{ NFSERR_NOTDIR,	-ENOTDIR	},
1100 	{ NFSERR_ISDIR,		-EISDIR		},
1101 	{ NFSERR_INVAL,		-EINVAL		},
1102 	{ NFSERR_FBIG,		-EFBIG		},
1103 	{ NFSERR_NOSPC,		-ENOSPC		},
1104 	{ NFSERR_ROFS,		-EROFS		},
1105 	{ NFSERR_MLINK,		-EMLINK		},
1106 	{ NFSERR_NAMETOOLONG,	-ENAMETOOLONG	},
1107 	{ NFSERR_NOTEMPTY,	-ENOTEMPTY	},
1108 	{ NFSERR_DQUOT,		-EDQUOT		},
1109 	{ NFSERR_STALE,		-ESTALE		},
1110 	{ NFSERR_REMOTE,	-EREMOTE	},
1111 #ifdef EWFLUSH
1112 	{ NFSERR_WFLUSH,	-EWFLUSH	},
1113 #endif
1114 	{ NFSERR_BADHANDLE,	-EBADHANDLE	},
1115 	{ NFSERR_NOT_SYNC,	-ENOTSYNC	},
1116 	{ NFSERR_BAD_COOKIE,	-EBADCOOKIE	},
1117 	{ NFSERR_NOTSUPP,	-ENOTSUPP	},
1118 	{ NFSERR_TOOSMALL,	-ETOOSMALL	},
1119 	{ NFSERR_SERVERFAULT,	-EREMOTEIO	},
1120 	{ NFSERR_BADTYPE,	-EBADTYPE	},
1121 	{ NFSERR_JUKEBOX,	-EJUKEBOX	},
1122 	{ -1,			-EIO		}
1123 };
1124 
1125 /**
1126  * nfs_stat_to_errno - convert an NFS status code to a local errno
1127  * @status: NFS status code to convert
1128  *
1129  * Returns a local errno value, or -EIO if the NFS status code is
1130  * not recognized.  This function is used jointly by NFSv2 and NFSv3.
1131  */
1132 static int nfs_stat_to_errno(enum nfs_stat status)
1133 {
1134 	int i;
1135 
1136 	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
1137 		if (nfs_errtbl[i].stat == (int)status)
1138 			return nfs_errtbl[i].errno;
1139 	}
1140 	dprintk("NFS: Unrecognized nfs status value: %u\n", status);
1141 	return nfs_errtbl[i].errno;
1142 }
1143 
1144 #define PROC(proc, argtype, restype, timer)				\
1145 [NFSPROC_##proc] = {							\
1146 	.p_proc	    =  NFSPROC_##proc,					\
1147 	.p_encode   =  nfs2_xdr_enc_##argtype,				\
1148 	.p_decode   =  nfs2_xdr_dec_##restype,				\
1149 	.p_arglen   =  NFS_##argtype##_sz,				\
1150 	.p_replen   =  NFS_##restype##_sz,				\
1151 	.p_timer    =  timer,						\
1152 	.p_statidx  =  NFSPROC_##proc,					\
1153 	.p_name     =  #proc,						\
1154 	}
1155 const struct rpc_procinfo nfs_procedures[] = {
1156 	PROC(GETATTR,	fhandle,	attrstat,	1),
1157 	PROC(SETATTR,	sattrargs,	attrstat,	0),
1158 	PROC(LOOKUP,	diropargs,	diropres,	2),
1159 	PROC(READLINK,	readlinkargs,	readlinkres,	3),
1160 	PROC(READ,	readargs,	readres,	3),
1161 	PROC(WRITE,	writeargs,	writeres,	4),
1162 	PROC(CREATE,	createargs,	diropres,	0),
1163 	PROC(REMOVE,	removeargs,	stat,		0),
1164 	PROC(RENAME,	renameargs,	stat,		0),
1165 	PROC(LINK,	linkargs,	stat,		0),
1166 	PROC(SYMLINK,	symlinkargs,	stat,		0),
1167 	PROC(MKDIR,	createargs,	diropres,	0),
1168 	PROC(RMDIR,	diropargs,	stat,		0),
1169 	PROC(READDIR,	readdirargs,	readdirres,	3),
1170 	PROC(STATFS,	fhandle,	statfsres,	0),
1171 };
1172 
1173 static unsigned int nfs_version2_counts[ARRAY_SIZE(nfs_procedures)];
1174 const struct rpc_version nfs_version2 = {
1175 	.number			= 2,
1176 	.nrprocs		= ARRAY_SIZE(nfs_procedures),
1177 	.procs			= nfs_procedures,
1178 	.counts			= nfs_version2_counts,
1179 };
1180