xref: /linux/fs/nfsd/nfsxdr.c (revision be58f7103700a68d5c7ca60a2bc0b309907599ab)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * XDR support for nfsd
4  *
5  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6  */
7 
8 #include "vfs.h"
9 #include "xdr.h"
10 #include "auth.h"
11 
12 /*
13  * Mapping of S_IF* types to NFS file types
14  */
15 static const u32 nfs_ftypes[] = {
16 	NFNON,  NFCHR,  NFCHR, NFBAD,
17 	NFDIR,  NFBAD,  NFBLK, NFBAD,
18 	NFREG,  NFBAD,  NFLNK, NFBAD,
19 	NFSOCK, NFBAD,  NFLNK, NFBAD,
20 };
21 
22 
23 /*
24  * Basic NFSv2 data types (RFC 1094 Section 2.3)
25  */
26 
27 /**
28  * svcxdr_encode_stat - Encode an NFSv2 status code
29  * @xdr: XDR stream
30  * @status: status value to encode
31  *
32  * Return values:
33  *   %false: Send buffer space was exhausted
34  *   %true: Success
35  */
36 bool
37 svcxdr_encode_stat(struct xdr_stream *xdr, __be32 status)
38 {
39 	__be32 *p;
40 
41 	p = xdr_reserve_space(xdr, sizeof(status));
42 	if (!p)
43 		return false;
44 	*p = status;
45 
46 	return true;
47 }
48 
49 /**
50  * svcxdr_decode_fhandle - Decode an NFSv2 file handle
51  * @xdr: XDR stream positioned at an encoded NFSv2 FH
52  * @fhp: OUT: filled-in server file handle
53  *
54  * Return values:
55  *  %false: The encoded file handle was not valid
56  *  %true: @fhp has been initialized
57  */
58 bool
59 svcxdr_decode_fhandle(struct xdr_stream *xdr, struct svc_fh *fhp)
60 {
61 	__be32 *p;
62 
63 	p = xdr_inline_decode(xdr, NFS_FHSIZE);
64 	if (!p)
65 		return false;
66 	fh_init(fhp, NFS_FHSIZE);
67 	memcpy(&fhp->fh_handle.fh_base, p, NFS_FHSIZE);
68 	fhp->fh_handle.fh_size = NFS_FHSIZE;
69 
70 	return true;
71 }
72 
73 static bool
74 svcxdr_encode_fhandle(struct xdr_stream *xdr, const struct svc_fh *fhp)
75 {
76 	__be32 *p;
77 
78 	p = xdr_reserve_space(xdr, NFS_FHSIZE);
79 	if (!p)
80 		return false;
81 	memcpy(p, &fhp->fh_handle.fh_base, NFS_FHSIZE);
82 
83 	return true;
84 }
85 
86 static __be32 *
87 encode_timeval(__be32 *p, const struct timespec64 *time)
88 {
89 	*p++ = cpu_to_be32((u32)time->tv_sec);
90 	if (time->tv_nsec)
91 		*p++ = cpu_to_be32(time->tv_nsec / NSEC_PER_USEC);
92 	else
93 		*p++ = xdr_zero;
94 	return p;
95 }
96 
97 static bool
98 svcxdr_decode_filename(struct xdr_stream *xdr, char **name, unsigned int *len)
99 {
100 	u32 size, i;
101 	__be32 *p;
102 	char *c;
103 
104 	if (xdr_stream_decode_u32(xdr, &size) < 0)
105 		return false;
106 	if (size == 0 || size > NFS_MAXNAMLEN)
107 		return false;
108 	p = xdr_inline_decode(xdr, size);
109 	if (!p)
110 		return false;
111 
112 	*len = size;
113 	*name = (char *)p;
114 	for (i = 0, c = *name; i < size; i++, c++)
115 		if (*c == '\0' || *c == '/')
116 			return false;
117 
118 	return true;
119 }
120 
121 static bool
122 svcxdr_decode_diropargs(struct xdr_stream *xdr, struct svc_fh *fhp,
123 			char **name, unsigned int *len)
124 {
125 	return svcxdr_decode_fhandle(xdr, fhp) &&
126 		svcxdr_decode_filename(xdr, name, len);
127 }
128 
129 static bool
130 svcxdr_decode_sattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
131 		    struct iattr *iap)
132 {
133 	u32 tmp1, tmp2;
134 	__be32 *p;
135 
136 	p = xdr_inline_decode(xdr, XDR_UNIT * 8);
137 	if (!p)
138 		return false;
139 
140 	iap->ia_valid = 0;
141 
142 	/*
143 	 * Some Sun clients put 0xffff in the mode field when they
144 	 * mean 0xffffffff.
145 	 */
146 	tmp1 = be32_to_cpup(p++);
147 	if (tmp1 != (u32)-1 && tmp1 != 0xffff) {
148 		iap->ia_valid |= ATTR_MODE;
149 		iap->ia_mode = tmp1;
150 	}
151 
152 	tmp1 = be32_to_cpup(p++);
153 	if (tmp1 != (u32)-1) {
154 		iap->ia_uid = make_kuid(nfsd_user_namespace(rqstp), tmp1);
155 		if (uid_valid(iap->ia_uid))
156 			iap->ia_valid |= ATTR_UID;
157 	}
158 
159 	tmp1 = be32_to_cpup(p++);
160 	if (tmp1 != (u32)-1) {
161 		iap->ia_gid = make_kgid(nfsd_user_namespace(rqstp), tmp1);
162 		if (gid_valid(iap->ia_gid))
163 			iap->ia_valid |= ATTR_GID;
164 	}
165 
166 	tmp1 = be32_to_cpup(p++);
167 	if (tmp1 != (u32)-1) {
168 		iap->ia_valid |= ATTR_SIZE;
169 		iap->ia_size = tmp1;
170 	}
171 
172 	tmp1 = be32_to_cpup(p++);
173 	tmp2 = be32_to_cpup(p++);
174 	if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
175 		iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
176 		iap->ia_atime.tv_sec = tmp1;
177 		iap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;
178 	}
179 
180 	tmp1 = be32_to_cpup(p++);
181 	tmp2 = be32_to_cpup(p++);
182 	if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
183 		iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
184 		iap->ia_mtime.tv_sec = tmp1;
185 		iap->ia_mtime.tv_nsec = tmp2 * NSEC_PER_USEC;
186 		/*
187 		 * Passing the invalid value useconds=1000000 for mtime
188 		 * is a Sun convention for "set both mtime and atime to
189 		 * current server time".  It's needed to make permissions
190 		 * checks for the "touch" program across v2 mounts to
191 		 * Solaris and Irix boxes work correctly. See description of
192 		 * sattr in section 6.1 of "NFS Illustrated" by
193 		 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
194 		 */
195 		if (tmp2 == 1000000)
196 			iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
197 	}
198 
199 	return true;
200 }
201 
202 /**
203  * svcxdr_encode_fattr - Encode NFSv2 file attributes
204  * @rqstp: Context of a completed RPC transaction
205  * @xdr: XDR stream
206  * @fhp: File handle to encode
207  * @stat: Attributes to encode
208  *
209  * Return values:
210  *   %false: Send buffer space was exhausted
211  *   %true: Success
212  */
213 bool
214 svcxdr_encode_fattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
215 		    const struct svc_fh *fhp, const struct kstat *stat)
216 {
217 	struct user_namespace *userns = nfsd_user_namespace(rqstp);
218 	struct dentry *dentry = fhp->fh_dentry;
219 	int type = stat->mode & S_IFMT;
220 	struct timespec64 time;
221 	__be32 *p;
222 	u32 fsid;
223 
224 	p = xdr_reserve_space(xdr, XDR_UNIT * 17);
225 	if (!p)
226 		return false;
227 
228 	*p++ = cpu_to_be32(nfs_ftypes[type >> 12]);
229 	*p++ = cpu_to_be32((u32)stat->mode);
230 	*p++ = cpu_to_be32((u32)stat->nlink);
231 	*p++ = cpu_to_be32((u32)from_kuid_munged(userns, stat->uid));
232 	*p++ = cpu_to_be32((u32)from_kgid_munged(userns, stat->gid));
233 
234 	if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN)
235 		*p++ = cpu_to_be32(NFS_MAXPATHLEN);
236 	else
237 		*p++ = cpu_to_be32((u32) stat->size);
238 	*p++ = cpu_to_be32((u32) stat->blksize);
239 	if (S_ISCHR(type) || S_ISBLK(type))
240 		*p++ = cpu_to_be32(new_encode_dev(stat->rdev));
241 	else
242 		*p++ = cpu_to_be32(0xffffffff);
243 	*p++ = cpu_to_be32((u32)stat->blocks);
244 
245 	switch (fsid_source(fhp)) {
246 	case FSIDSOURCE_FSID:
247 		fsid = (u32)fhp->fh_export->ex_fsid;
248 		break;
249 	case FSIDSOURCE_UUID:
250 		fsid = ((u32 *)fhp->fh_export->ex_uuid)[0];
251 		fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[1];
252 		fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[2];
253 		fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[3];
254 		break;
255 	default:
256 		fsid = new_encode_dev(stat->dev);
257 		break;
258 	}
259 	*p++ = cpu_to_be32(fsid);
260 
261 	*p++ = cpu_to_be32((u32)stat->ino);
262 	p = encode_timeval(p, &stat->atime);
263 	time = stat->mtime;
264 	lease_get_mtime(d_inode(dentry), &time);
265 	p = encode_timeval(p, &time);
266 	encode_timeval(p, &stat->ctime);
267 
268 	return true;
269 }
270 
271 /*
272  * XDR decode functions
273  */
274 
275 int
276 nfssvc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p)
277 {
278 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
279 	struct nfsd_fhandle *args = rqstp->rq_argp;
280 
281 	return svcxdr_decode_fhandle(xdr, &args->fh);
282 }
283 
284 int
285 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
286 {
287 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
288 	struct nfsd_sattrargs *args = rqstp->rq_argp;
289 
290 	return svcxdr_decode_fhandle(xdr, &args->fh) &&
291 		svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
292 }
293 
294 int
295 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
296 {
297 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
298 	struct nfsd_diropargs *args = rqstp->rq_argp;
299 
300 	return svcxdr_decode_diropargs(xdr, &args->fh, &args->name, &args->len);
301 }
302 
303 int
304 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
305 {
306 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
307 	struct nfsd_readargs *args = rqstp->rq_argp;
308 	u32 totalcount;
309 
310 	if (!svcxdr_decode_fhandle(xdr, &args->fh))
311 		return 0;
312 	if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
313 		return 0;
314 	if (xdr_stream_decode_u32(xdr, &args->count) < 0)
315 		return 0;
316 	/* totalcount is ignored */
317 	if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
318 		return 0;
319 
320 	return 1;
321 }
322 
323 int
324 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
325 {
326 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
327 	struct nfsd_writeargs *args = rqstp->rq_argp;
328 	struct kvec *head = rqstp->rq_arg.head;
329 	struct kvec *tail = rqstp->rq_arg.tail;
330 	u32 beginoffset, totalcount;
331 	size_t remaining;
332 
333 	if (!svcxdr_decode_fhandle(xdr, &args->fh))
334 		return 0;
335 	/* beginoffset is ignored */
336 	if (xdr_stream_decode_u32(xdr, &beginoffset) < 0)
337 		return 0;
338 	if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
339 		return 0;
340 	/* totalcount is ignored */
341 	if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
342 		return 0;
343 
344 	/* opaque data */
345 	if (xdr_stream_decode_u32(xdr, &args->len) < 0)
346 		return 0;
347 	if (args->len > NFSSVC_MAXBLKSIZE_V2)
348 		return 0;
349 	remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
350 	remaining -= xdr_stream_pos(xdr);
351 	if (remaining < xdr_align_size(args->len))
352 		return 0;
353 	args->first.iov_base = xdr->p;
354 	args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
355 
356 	return 1;
357 }
358 
359 int
360 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
361 {
362 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
363 	struct nfsd_createargs *args = rqstp->rq_argp;
364 
365 	return svcxdr_decode_diropargs(xdr, &args->fh,
366 				       &args->name, &args->len) &&
367 		svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
368 }
369 
370 int
371 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
372 {
373 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
374 	struct nfsd_renameargs *args = rqstp->rq_argp;
375 
376 	return svcxdr_decode_diropargs(xdr, &args->ffh,
377 				       &args->fname, &args->flen) &&
378 		svcxdr_decode_diropargs(xdr, &args->tfh,
379 					&args->tname, &args->tlen);
380 }
381 
382 int
383 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
384 {
385 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
386 	struct nfsd_linkargs *args = rqstp->rq_argp;
387 
388 	return svcxdr_decode_fhandle(xdr, &args->ffh) &&
389 		svcxdr_decode_diropargs(xdr, &args->tfh,
390 					&args->tname, &args->tlen);
391 }
392 
393 int
394 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
395 {
396 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
397 	struct nfsd_symlinkargs *args = rqstp->rq_argp;
398 	struct kvec *head = rqstp->rq_arg.head;
399 
400 	if (!svcxdr_decode_diropargs(xdr, &args->ffh, &args->fname, &args->flen))
401 		return 0;
402 	if (xdr_stream_decode_u32(xdr, &args->tlen) < 0)
403 		return 0;
404 	if (args->tlen == 0)
405 		return 0;
406 
407 	args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
408 	args->first.iov_base = xdr_inline_decode(xdr, args->tlen);
409 	if (!args->first.iov_base)
410 		return 0;
411 	return svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
412 }
413 
414 int
415 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
416 {
417 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
418 	struct nfsd_readdirargs *args = rqstp->rq_argp;
419 
420 	if (!svcxdr_decode_fhandle(xdr, &args->fh))
421 		return 0;
422 	if (xdr_stream_decode_u32(xdr, &args->cookie) < 0)
423 		return 0;
424 	if (xdr_stream_decode_u32(xdr, &args->count) < 0)
425 		return 0;
426 
427 	return 1;
428 }
429 
430 /*
431  * XDR encode functions
432  */
433 
434 int
435 nfssvc_encode_statres(struct svc_rqst *rqstp, __be32 *p)
436 {
437 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
438 	struct nfsd_stat *resp = rqstp->rq_resp;
439 
440 	return svcxdr_encode_stat(xdr, resp->status);
441 }
442 
443 int
444 nfssvc_encode_attrstatres(struct svc_rqst *rqstp, __be32 *p)
445 {
446 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
447 	struct nfsd_attrstat *resp = rqstp->rq_resp;
448 
449 	if (!svcxdr_encode_stat(xdr, resp->status))
450 		return 0;
451 	switch (resp->status) {
452 	case nfs_ok:
453 		if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
454 			return 0;
455 		break;
456 	}
457 
458 	return 1;
459 }
460 
461 int
462 nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
463 {
464 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
465 	struct nfsd_diropres *resp = rqstp->rq_resp;
466 
467 	if (!svcxdr_encode_stat(xdr, resp->status))
468 		return 0;
469 	switch (resp->status) {
470 	case nfs_ok:
471 		if (!svcxdr_encode_fhandle(xdr, &resp->fh))
472 			return 0;
473 		if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
474 			return 0;
475 		break;
476 	}
477 
478 	return 1;
479 }
480 
481 int
482 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
483 {
484 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
485 	struct nfsd_readlinkres *resp = rqstp->rq_resp;
486 	struct kvec *head = rqstp->rq_res.head;
487 
488 	if (!svcxdr_encode_stat(xdr, resp->status))
489 		return 0;
490 	switch (resp->status) {
491 	case nfs_ok:
492 		if (xdr_stream_encode_u32(xdr, resp->len) < 0)
493 			return 0;
494 		xdr_write_pages(xdr, &resp->page, 0, resp->len);
495 		if (svc_encode_result_payload(rqstp, head->iov_len, resp->len) < 0)
496 			return 0;
497 		break;
498 	}
499 
500 	return 1;
501 }
502 
503 int
504 nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
505 {
506 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
507 	struct nfsd_readres *resp = rqstp->rq_resp;
508 	struct kvec *head = rqstp->rq_res.head;
509 
510 	if (!svcxdr_encode_stat(xdr, resp->status))
511 		return 0;
512 	switch (resp->status) {
513 	case nfs_ok:
514 		if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
515 			return 0;
516 		if (xdr_stream_encode_u32(xdr, resp->count) < 0)
517 			return 0;
518 		xdr_write_pages(xdr, resp->pages, rqstp->rq_res.page_base,
519 				resp->count);
520 		if (svc_encode_result_payload(rqstp, head->iov_len, resp->count) < 0)
521 			return 0;
522 		break;
523 	}
524 
525 	return 1;
526 }
527 
528 int
529 nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
530 {
531 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
532 	struct nfsd_readdirres *resp = rqstp->rq_resp;
533 	struct xdr_buf *dirlist = &resp->dirlist;
534 
535 	if (!svcxdr_encode_stat(xdr, resp->status))
536 		return 0;
537 	switch (resp->status) {
538 	case nfs_ok:
539 		xdr_write_pages(xdr, dirlist->pages, 0, dirlist->len);
540 		/* no more entries */
541 		if (xdr_stream_encode_item_absent(xdr) < 0)
542 			return 0;
543 		if (xdr_stream_encode_bool(xdr, resp->common.err == nfserr_eof) < 0)
544 			return 0;
545 		break;
546 	}
547 
548 	return 1;
549 }
550 
551 int
552 nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
553 {
554 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
555 	struct nfsd_statfsres *resp = rqstp->rq_resp;
556 	struct kstatfs	*stat = &resp->stats;
557 
558 	if (!svcxdr_encode_stat(xdr, resp->status))
559 		return 0;
560 	switch (resp->status) {
561 	case nfs_ok:
562 		p = xdr_reserve_space(xdr, XDR_UNIT * 5);
563 		if (!p)
564 			return 0;
565 		*p++ = cpu_to_be32(NFSSVC_MAXBLKSIZE_V2);
566 		*p++ = cpu_to_be32(stat->f_bsize);
567 		*p++ = cpu_to_be32(stat->f_blocks);
568 		*p++ = cpu_to_be32(stat->f_bfree);
569 		*p = cpu_to_be32(stat->f_bavail);
570 		break;
571 	}
572 
573 	return 1;
574 }
575 
576 /**
577  * nfssvc_encode_nfscookie - Encode a directory offset cookie
578  * @resp: readdir result context
579  * @offset: offset cookie to encode
580  *
581  * The buffer space for the offset cookie has already been reserved
582  * by svcxdr_encode_entry_common().
583  */
584 void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset)
585 {
586 	__be32 cookie = cpu_to_be32(offset);
587 
588 	if (!resp->cookie_offset)
589 		return;
590 
591 	write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie,
592 			       sizeof(cookie));
593 	resp->cookie_offset = 0;
594 }
595 
596 static bool
597 svcxdr_encode_entry_common(struct nfsd_readdirres *resp, const char *name,
598 			   int namlen, loff_t offset, u64 ino)
599 {
600 	struct xdr_buf *dirlist = &resp->dirlist;
601 	struct xdr_stream *xdr = &resp->xdr;
602 
603 	if (xdr_stream_encode_item_present(xdr) < 0)
604 		return false;
605 	/* fileid */
606 	if (xdr_stream_encode_u32(xdr, (u32)ino) < 0)
607 		return false;
608 	/* name */
609 	if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS2_MAXNAMLEN)) < 0)
610 		return false;
611 	/* cookie */
612 	resp->cookie_offset = dirlist->len;
613 	if (xdr_stream_encode_u32(xdr, ~0U) < 0)
614 		return false;
615 
616 	return true;
617 }
618 
619 /**
620  * nfssvc_encode_entry - encode one NFSv2 READDIR entry
621  * @data: directory context
622  * @name: name of the object to be encoded
623  * @namlen: length of that name, in bytes
624  * @offset: the offset of the previous entry
625  * @ino: the fileid of this entry
626  * @d_type: unused
627  *
628  * Return values:
629  *   %0: Entry was successfully encoded.
630  *   %-EINVAL: An encoding problem occured, secondary status code in resp->common.err
631  *
632  * On exit, the following fields are updated:
633  *   - resp->xdr
634  *   - resp->common.err
635  *   - resp->cookie_offset
636  */
637 int nfssvc_encode_entry(void *data, const char *name, int namlen,
638 			loff_t offset, u64 ino, unsigned int d_type)
639 {
640 	struct readdir_cd *ccd = data;
641 	struct nfsd_readdirres *resp = container_of(ccd,
642 						    struct nfsd_readdirres,
643 						    common);
644 	unsigned int starting_length = resp->dirlist.len;
645 
646 	/* The offset cookie for the previous entry */
647 	nfssvc_encode_nfscookie(resp, offset);
648 
649 	if (!svcxdr_encode_entry_common(resp, name, namlen, offset, ino))
650 		goto out_toosmall;
651 
652 	xdr_commit_encode(&resp->xdr);
653 	resp->common.err = nfs_ok;
654 	return 0;
655 
656 out_toosmall:
657 	resp->cookie_offset = 0;
658 	resp->common.err = nfserr_toosmall;
659 	resp->dirlist.len = starting_length;
660 	return -EINVAL;
661 }
662 
663 /*
664  * XDR release functions
665  */
666 void nfssvc_release_attrstat(struct svc_rqst *rqstp)
667 {
668 	struct nfsd_attrstat *resp = rqstp->rq_resp;
669 
670 	fh_put(&resp->fh);
671 }
672 
673 void nfssvc_release_diropres(struct svc_rqst *rqstp)
674 {
675 	struct nfsd_diropres *resp = rqstp->rq_resp;
676 
677 	fh_put(&resp->fh);
678 }
679 
680 void nfssvc_release_readres(struct svc_rqst *rqstp)
681 {
682 	struct nfsd_readres *resp = rqstp->rq_resp;
683 
684 	fh_put(&resp->fh);
685 }
686