xref: /openbmc/linux/fs/nfs/callback_xdr.c (revision b6dcefde)
1 /*
2  * linux/fs/nfs/callback_xdr.c
3  *
4  * Copyright (C) 2004 Trond Myklebust
5  *
6  * NFSv4 callback encode/decode procedures
7  */
8 #include <linux/kernel.h>
9 #include <linux/sunrpc/svc.h>
10 #include <linux/nfs4.h>
11 #include <linux/nfs_fs.h>
12 #include "nfs4_fs.h"
13 #include "callback.h"
14 
15 #define CB_OP_TAGLEN_MAXSZ	(512)
16 #define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
17 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
18 #define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
19 				CB_OP_GETATTR_BITMAP_MAXSZ + \
20 				2 + 2 + 3 + 3)
21 #define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
22 
23 #if defined(CONFIG_NFS_V4_1)
24 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
25 					4 + 1 + 3)
26 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
27 #endif /* CONFIG_NFS_V4_1 */
28 
29 #define NFSDBG_FACILITY NFSDBG_CALLBACK
30 
31 typedef __be32 (*callback_process_op_t)(void *, void *);
32 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
33 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
34 
35 
36 struct callback_op {
37 	callback_process_op_t process_op;
38 	callback_decode_arg_t decode_args;
39 	callback_encode_res_t encode_res;
40 	long res_maxsize;
41 };
42 
43 static struct callback_op callback_ops[];
44 
45 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
46 {
47 	return htonl(NFS4_OK);
48 }
49 
50 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
51 {
52 	return xdr_argsize_check(rqstp, p);
53 }
54 
55 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
56 {
57 	return xdr_ressize_check(rqstp, p);
58 }
59 
60 static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
61 {
62 	__be32 *p;
63 
64 	p = xdr_inline_decode(xdr, nbytes);
65 	if (unlikely(p == NULL))
66 		printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
67 	return p;
68 }
69 
70 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
71 {
72 	__be32 *p;
73 
74 	p = read_buf(xdr, 4);
75 	if (unlikely(p == NULL))
76 		return htonl(NFS4ERR_RESOURCE);
77 	*len = ntohl(*p);
78 
79 	if (*len != 0) {
80 		p = read_buf(xdr, *len);
81 		if (unlikely(p == NULL))
82 			return htonl(NFS4ERR_RESOURCE);
83 		*str = (const char *)p;
84 	} else
85 		*str = NULL;
86 
87 	return 0;
88 }
89 
90 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
91 {
92 	__be32 *p;
93 
94 	p = read_buf(xdr, 4);
95 	if (unlikely(p == NULL))
96 		return htonl(NFS4ERR_RESOURCE);
97 	fh->size = ntohl(*p);
98 	if (fh->size > NFS4_FHSIZE)
99 		return htonl(NFS4ERR_BADHANDLE);
100 	p = read_buf(xdr, fh->size);
101 	if (unlikely(p == NULL))
102 		return htonl(NFS4ERR_RESOURCE);
103 	memcpy(&fh->data[0], p, fh->size);
104 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
105 	return 0;
106 }
107 
108 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
109 {
110 	__be32 *p;
111 	unsigned int attrlen;
112 
113 	p = read_buf(xdr, 4);
114 	if (unlikely(p == NULL))
115 		return htonl(NFS4ERR_RESOURCE);
116 	attrlen = ntohl(*p);
117 	p = read_buf(xdr, attrlen << 2);
118 	if (unlikely(p == NULL))
119 		return htonl(NFS4ERR_RESOURCE);
120 	if (likely(attrlen > 0))
121 		bitmap[0] = ntohl(*p++);
122 	if (attrlen > 1)
123 		bitmap[1] = ntohl(*p);
124 	return 0;
125 }
126 
127 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
128 {
129 	__be32 *p;
130 
131 	p = read_buf(xdr, 16);
132 	if (unlikely(p == NULL))
133 		return htonl(NFS4ERR_RESOURCE);
134 	memcpy(stateid->data, p, 16);
135 	return 0;
136 }
137 
138 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
139 {
140 	__be32 *p;
141 	__be32 status;
142 
143 	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
144 	if (unlikely(status != 0))
145 		return status;
146 	/* We do not like overly long tags! */
147 	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
148 		printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
149 				__func__, hdr->taglen);
150 		return htonl(NFS4ERR_RESOURCE);
151 	}
152 	p = read_buf(xdr, 12);
153 	if (unlikely(p == NULL))
154 		return htonl(NFS4ERR_RESOURCE);
155 	hdr->minorversion = ntohl(*p++);
156 	/* Check minor version is zero or one. */
157 	if (hdr->minorversion <= 1) {
158 		p++;	/* skip callback_ident */
159 	} else {
160 		printk(KERN_WARNING "%s: NFSv4 server callback with "
161 			"illegal minor version %u!\n",
162 			__func__, hdr->minorversion);
163 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
164 	}
165 	hdr->nops = ntohl(*p);
166 	dprintk("%s: minorversion %d nops %d\n", __func__,
167 		hdr->minorversion, hdr->nops);
168 	return 0;
169 }
170 
171 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
172 {
173 	__be32 *p;
174 	p = read_buf(xdr, 4);
175 	if (unlikely(p == NULL))
176 		return htonl(NFS4ERR_RESOURCE);
177 	*op = ntohl(*p);
178 	return 0;
179 }
180 
181 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
182 {
183 	__be32 status;
184 
185 	status = decode_fh(xdr, &args->fh);
186 	if (unlikely(status != 0))
187 		goto out;
188 	args->addr = svc_addr(rqstp);
189 	status = decode_bitmap(xdr, args->bitmap);
190 out:
191 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
192 	return status;
193 }
194 
195 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
196 {
197 	__be32 *p;
198 	__be32 status;
199 
200 	args->addr = svc_addr(rqstp);
201 	status = decode_stateid(xdr, &args->stateid);
202 	if (unlikely(status != 0))
203 		goto out;
204 	p = read_buf(xdr, 4);
205 	if (unlikely(p == NULL)) {
206 		status = htonl(NFS4ERR_RESOURCE);
207 		goto out;
208 	}
209 	args->truncate = ntohl(*p);
210 	status = decode_fh(xdr, &args->fh);
211 out:
212 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
213 	return status;
214 }
215 
216 #if defined(CONFIG_NFS_V4_1)
217 
218 static unsigned decode_sessionid(struct xdr_stream *xdr,
219 				 struct nfs4_sessionid *sid)
220 {
221 	uint32_t *p;
222 	int len = NFS4_MAX_SESSIONID_LEN;
223 
224 	p = read_buf(xdr, len);
225 	if (unlikely(p == NULL))
226 		return htonl(NFS4ERR_RESOURCE);
227 
228 	memcpy(sid->data, p, len);
229 	return 0;
230 }
231 
232 static unsigned decode_rc_list(struct xdr_stream *xdr,
233 			       struct referring_call_list *rc_list)
234 {
235 	uint32_t *p;
236 	int i;
237 	unsigned status;
238 
239 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
240 	if (status)
241 		goto out;
242 
243 	status = htonl(NFS4ERR_RESOURCE);
244 	p = read_buf(xdr, sizeof(uint32_t));
245 	if (unlikely(p == NULL))
246 		goto out;
247 
248 	rc_list->rcl_nrefcalls = ntohl(*p++);
249 	if (rc_list->rcl_nrefcalls) {
250 		p = read_buf(xdr,
251 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
252 		if (unlikely(p == NULL))
253 			goto out;
254 		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
255 						sizeof(*rc_list->rcl_refcalls),
256 						GFP_KERNEL);
257 		if (unlikely(rc_list->rcl_refcalls == NULL))
258 			goto out;
259 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
260 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
261 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
262 		}
263 	}
264 	status = 0;
265 
266 out:
267 	return status;
268 }
269 
270 static unsigned decode_cb_sequence_args(struct svc_rqst *rqstp,
271 					struct xdr_stream *xdr,
272 					struct cb_sequenceargs *args)
273 {
274 	uint32_t *p;
275 	int i;
276 	unsigned status;
277 
278 	status = decode_sessionid(xdr, &args->csa_sessionid);
279 	if (status)
280 		goto out;
281 
282 	status = htonl(NFS4ERR_RESOURCE);
283 	p = read_buf(xdr, 5 * sizeof(uint32_t));
284 	if (unlikely(p == NULL))
285 		goto out;
286 
287 	args->csa_addr = svc_addr(rqstp);
288 	args->csa_sequenceid = ntohl(*p++);
289 	args->csa_slotid = ntohl(*p++);
290 	args->csa_highestslotid = ntohl(*p++);
291 	args->csa_cachethis = ntohl(*p++);
292 	args->csa_nrclists = ntohl(*p++);
293 	args->csa_rclists = NULL;
294 	if (args->csa_nrclists) {
295 		args->csa_rclists = kmalloc(args->csa_nrclists *
296 					    sizeof(*args->csa_rclists),
297 					    GFP_KERNEL);
298 		if (unlikely(args->csa_rclists == NULL))
299 			goto out;
300 
301 		for (i = 0; i < args->csa_nrclists; i++) {
302 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
303 			if (status)
304 				goto out_free;
305 		}
306 	}
307 	status = 0;
308 
309 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
310 		"highestslotid %u cachethis %d nrclists %u\n",
311 		__func__,
312 		((u32 *)&args->csa_sessionid)[0],
313 		((u32 *)&args->csa_sessionid)[1],
314 		((u32 *)&args->csa_sessionid)[2],
315 		((u32 *)&args->csa_sessionid)[3],
316 		args->csa_sequenceid, args->csa_slotid,
317 		args->csa_highestslotid, args->csa_cachethis,
318 		args->csa_nrclists);
319 out:
320 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
321 	return status;
322 
323 out_free:
324 	for (i = 0; i < args->csa_nrclists; i++)
325 		kfree(args->csa_rclists[i].rcl_refcalls);
326 	kfree(args->csa_rclists);
327 	goto out;
328 }
329 
330 static unsigned decode_recallany_args(struct svc_rqst *rqstp,
331 				      struct xdr_stream *xdr,
332 				      struct cb_recallanyargs *args)
333 {
334 	uint32_t *p;
335 
336 	args->craa_addr = svc_addr(rqstp);
337 	p = read_buf(xdr, 4);
338 	if (unlikely(p == NULL))
339 		return htonl(NFS4ERR_BADXDR);
340 	args->craa_objs_to_keep = ntohl(*p++);
341 	p = read_buf(xdr, 4);
342 	if (unlikely(p == NULL))
343 		return htonl(NFS4ERR_BADXDR);
344 	args->craa_type_mask = ntohl(*p);
345 
346 	return 0;
347 }
348 
349 #endif /* CONFIG_NFS_V4_1 */
350 
351 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
352 {
353 	__be32 *p;
354 
355 	p = xdr_reserve_space(xdr, 4 + len);
356 	if (unlikely(p == NULL))
357 		return htonl(NFS4ERR_RESOURCE);
358 	xdr_encode_opaque(p, str, len);
359 	return 0;
360 }
361 
362 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
363 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
364 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
365 {
366 	__be32 bm[2];
367 	__be32 *p;
368 
369 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
370 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
371 	if (bm[1] != 0) {
372 		p = xdr_reserve_space(xdr, 16);
373 		if (unlikely(p == NULL))
374 			return htonl(NFS4ERR_RESOURCE);
375 		*p++ = htonl(2);
376 		*p++ = bm[0];
377 		*p++ = bm[1];
378 	} else if (bm[0] != 0) {
379 		p = xdr_reserve_space(xdr, 12);
380 		if (unlikely(p == NULL))
381 			return htonl(NFS4ERR_RESOURCE);
382 		*p++ = htonl(1);
383 		*p++ = bm[0];
384 	} else {
385 		p = xdr_reserve_space(xdr, 8);
386 		if (unlikely(p == NULL))
387 			return htonl(NFS4ERR_RESOURCE);
388 		*p++ = htonl(0);
389 	}
390 	*savep = p;
391 	return 0;
392 }
393 
394 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
395 {
396 	__be32 *p;
397 
398 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
399 		return 0;
400 	p = xdr_reserve_space(xdr, 8);
401 	if (unlikely(!p))
402 		return htonl(NFS4ERR_RESOURCE);
403 	p = xdr_encode_hyper(p, change);
404 	return 0;
405 }
406 
407 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
408 {
409 	__be32 *p;
410 
411 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
412 		return 0;
413 	p = xdr_reserve_space(xdr, 8);
414 	if (unlikely(!p))
415 		return htonl(NFS4ERR_RESOURCE);
416 	p = xdr_encode_hyper(p, size);
417 	return 0;
418 }
419 
420 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
421 {
422 	__be32 *p;
423 
424 	p = xdr_reserve_space(xdr, 12);
425 	if (unlikely(!p))
426 		return htonl(NFS4ERR_RESOURCE);
427 	p = xdr_encode_hyper(p, time->tv_sec);
428 	*p = htonl(time->tv_nsec);
429 	return 0;
430 }
431 
432 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
433 {
434 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
435 		return 0;
436 	return encode_attr_time(xdr,time);
437 }
438 
439 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
440 {
441 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
442 		return 0;
443 	return encode_attr_time(xdr,time);
444 }
445 
446 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
447 {
448 	__be32 status;
449 
450 	hdr->status = xdr_reserve_space(xdr, 4);
451 	if (unlikely(hdr->status == NULL))
452 		return htonl(NFS4ERR_RESOURCE);
453 	status = encode_string(xdr, hdr->taglen, hdr->tag);
454 	if (unlikely(status != 0))
455 		return status;
456 	hdr->nops = xdr_reserve_space(xdr, 4);
457 	if (unlikely(hdr->nops == NULL))
458 		return htonl(NFS4ERR_RESOURCE);
459 	return 0;
460 }
461 
462 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
463 {
464 	__be32 *p;
465 
466 	p = xdr_reserve_space(xdr, 8);
467 	if (unlikely(p == NULL))
468 		return htonl(NFS4ERR_RESOURCE);
469 	*p++ = htonl(op);
470 	*p = res;
471 	return 0;
472 }
473 
474 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
475 {
476 	__be32 *savep = NULL;
477 	__be32 status = res->status;
478 
479 	if (unlikely(status != 0))
480 		goto out;
481 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
482 	if (unlikely(status != 0))
483 		goto out;
484 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
485 	if (unlikely(status != 0))
486 		goto out;
487 	status = encode_attr_size(xdr, res->bitmap, res->size);
488 	if (unlikely(status != 0))
489 		goto out;
490 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
491 	if (unlikely(status != 0))
492 		goto out;
493 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
494 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
495 out:
496 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
497 	return status;
498 }
499 
500 #if defined(CONFIG_NFS_V4_1)
501 
502 static unsigned encode_sessionid(struct xdr_stream *xdr,
503 				 const struct nfs4_sessionid *sid)
504 {
505 	uint32_t *p;
506 	int len = NFS4_MAX_SESSIONID_LEN;
507 
508 	p = xdr_reserve_space(xdr, len);
509 	if (unlikely(p == NULL))
510 		return htonl(NFS4ERR_RESOURCE);
511 
512 	memcpy(p, sid, len);
513 	return 0;
514 }
515 
516 static unsigned encode_cb_sequence_res(struct svc_rqst *rqstp,
517 				       struct xdr_stream *xdr,
518 				       const struct cb_sequenceres *res)
519 {
520 	uint32_t *p;
521 	unsigned status = res->csr_status;
522 
523 	if (unlikely(status != 0))
524 		goto out;
525 
526 	encode_sessionid(xdr, &res->csr_sessionid);
527 
528 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
529 	if (unlikely(p == NULL))
530 		return htonl(NFS4ERR_RESOURCE);
531 
532 	*p++ = htonl(res->csr_sequenceid);
533 	*p++ = htonl(res->csr_slotid);
534 	*p++ = htonl(res->csr_highestslotid);
535 	*p++ = htonl(res->csr_target_highestslotid);
536 out:
537 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
538 	return status;
539 }
540 
541 static __be32
542 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
543 {
544 	if (op_nr == OP_CB_SEQUENCE) {
545 		if (nop != 0)
546 			return htonl(NFS4ERR_SEQUENCE_POS);
547 	} else {
548 		if (nop == 0)
549 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
550 	}
551 
552 	switch (op_nr) {
553 	case OP_CB_GETATTR:
554 	case OP_CB_RECALL:
555 	case OP_CB_SEQUENCE:
556 	case OP_CB_RECALL_ANY:
557 		*op = &callback_ops[op_nr];
558 		break;
559 
560 	case OP_CB_LAYOUTRECALL:
561 	case OP_CB_NOTIFY_DEVICEID:
562 	case OP_CB_NOTIFY:
563 	case OP_CB_PUSH_DELEG:
564 	case OP_CB_RECALLABLE_OBJ_AVAIL:
565 	case OP_CB_RECALL_SLOT:
566 	case OP_CB_WANTS_CANCELLED:
567 	case OP_CB_NOTIFY_LOCK:
568 		return htonl(NFS4ERR_NOTSUPP);
569 
570 	default:
571 		return htonl(NFS4ERR_OP_ILLEGAL);
572 	}
573 
574 	return htonl(NFS_OK);
575 }
576 
577 #else /* CONFIG_NFS_V4_1 */
578 
579 static __be32
580 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
581 {
582 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
583 }
584 
585 #endif /* CONFIG_NFS_V4_1 */
586 
587 static __be32
588 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
589 {
590 	switch (op_nr) {
591 	case OP_CB_GETATTR:
592 	case OP_CB_RECALL:
593 		*op = &callback_ops[op_nr];
594 		break;
595 	default:
596 		return htonl(NFS4ERR_OP_ILLEGAL);
597 	}
598 
599 	return htonl(NFS_OK);
600 }
601 
602 static __be32 process_op(uint32_t minorversion, int nop,
603 		struct svc_rqst *rqstp,
604 		struct xdr_stream *xdr_in, void *argp,
605 		struct xdr_stream *xdr_out, void *resp)
606 {
607 	struct callback_op *op = &callback_ops[0];
608 	unsigned int op_nr = OP_CB_ILLEGAL;
609 	__be32 status;
610 	long maxlen;
611 	__be32 res;
612 
613 	dprintk("%s: start\n", __func__);
614 	status = decode_op_hdr(xdr_in, &op_nr);
615 	if (unlikely(status)) {
616 		status = htonl(NFS4ERR_OP_ILLEGAL);
617 		goto out;
618 	}
619 
620 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
621 		__func__, minorversion, nop, op_nr);
622 
623 	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
624 				preprocess_nfs4_op(op_nr, &op);
625 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
626 		op_nr = OP_CB_ILLEGAL;
627 out:
628 	maxlen = xdr_out->end - xdr_out->p;
629 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
630 		if (likely(status == 0 && op->decode_args != NULL))
631 			status = op->decode_args(rqstp, xdr_in, argp);
632 		if (likely(status == 0 && op->process_op != NULL))
633 			status = op->process_op(argp, resp);
634 	} else
635 		status = htonl(NFS4ERR_RESOURCE);
636 
637 	res = encode_op_hdr(xdr_out, op_nr, status);
638 	if (status == 0)
639 		status = res;
640 	if (op->encode_res != NULL && status == 0)
641 		status = op->encode_res(rqstp, xdr_out, resp);
642 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
643 	return status;
644 }
645 
646 /*
647  * Decode, process and encode a COMPOUND
648  */
649 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
650 {
651 	struct cb_compound_hdr_arg hdr_arg = { 0 };
652 	struct cb_compound_hdr_res hdr_res = { NULL };
653 	struct xdr_stream xdr_in, xdr_out;
654 	__be32 *p;
655 	__be32 status;
656 	unsigned int nops = 0;
657 
658 	dprintk("%s: start\n", __func__);
659 
660 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
661 
662 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
663 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
664 
665 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
666 	if (status == __constant_htonl(NFS4ERR_RESOURCE))
667 		return rpc_garbage_args;
668 
669 	hdr_res.taglen = hdr_arg.taglen;
670 	hdr_res.tag = hdr_arg.tag;
671 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
672 		return rpc_system_err;
673 
674 	while (status == 0 && nops != hdr_arg.nops) {
675 		status = process_op(hdr_arg.minorversion, nops,
676 				    rqstp, &xdr_in, argp, &xdr_out, resp);
677 		nops++;
678 	}
679 
680 	*hdr_res.status = status;
681 	*hdr_res.nops = htonl(nops);
682 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
683 	return rpc_success;
684 }
685 
686 /*
687  * Define NFS4 callback COMPOUND ops.
688  */
689 static struct callback_op callback_ops[] = {
690 	[0] = {
691 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
692 	},
693 	[OP_CB_GETATTR] = {
694 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
695 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
696 		.encode_res = (callback_encode_res_t)encode_getattr_res,
697 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
698 	},
699 	[OP_CB_RECALL] = {
700 		.process_op = (callback_process_op_t)nfs4_callback_recall,
701 		.decode_args = (callback_decode_arg_t)decode_recall_args,
702 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
703 	},
704 #if defined(CONFIG_NFS_V4_1)
705 	[OP_CB_SEQUENCE] = {
706 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
707 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
708 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
709 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
710 	},
711 	[OP_CB_RECALL_ANY] = {
712 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
713 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
714 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
715 	},
716 #endif /* CONFIG_NFS_V4_1 */
717 };
718 
719 /*
720  * Define NFS4 callback procedures
721  */
722 static struct svc_procedure nfs4_callback_procedures1[] = {
723 	[CB_NULL] = {
724 		.pc_func = nfs4_callback_null,
725 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
726 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
727 		.pc_xdrressize = 1,
728 	},
729 	[CB_COMPOUND] = {
730 		.pc_func = nfs4_callback_compound,
731 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
732 		.pc_argsize = 256,
733 		.pc_ressize = 256,
734 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
735 	}
736 };
737 
738 struct svc_version nfs4_callback_version1 = {
739 	.vs_vers = 1,
740 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
741 	.vs_proc = nfs4_callback_procedures1,
742 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
743 	.vs_dispatch = NULL,
744 };
745 
746 struct svc_version nfs4_callback_version4 = {
747 	.vs_vers = 4,
748 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
749 	.vs_proc = nfs4_callback_procedures1,
750 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
751 	.vs_dispatch = NULL,
752 };
753