xref: /linux/fs/nfs/callback_xdr.c (revision 0dd9ac63ce26ec87b080ca9c3e6efed33c23ace6)
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 <linux/slab.h>
13 #include "nfs4_fs.h"
14 #include "callback.h"
15 
16 #define CB_OP_TAGLEN_MAXSZ	(512)
17 #define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
18 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
19 #define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
20 				CB_OP_GETATTR_BITMAP_MAXSZ + \
21 				2 + 2 + 3 + 3)
22 #define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
23 
24 #if defined(CONFIG_NFS_V4_1)
25 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
26 					4 + 1 + 3)
27 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
28 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
29 #endif /* CONFIG_NFS_V4_1 */
30 
31 #define NFSDBG_FACILITY NFSDBG_CALLBACK
32 
33 /* Internal error code */
34 #define NFS4ERR_RESOURCE_HDR	11050
35 
36 typedef __be32 (*callback_process_op_t)(void *, void *);
37 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
38 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
39 
40 
41 struct callback_op {
42 	callback_process_op_t process_op;
43 	callback_decode_arg_t decode_args;
44 	callback_encode_res_t encode_res;
45 	long res_maxsize;
46 };
47 
48 static struct callback_op callback_ops[];
49 
50 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
51 {
52 	return htonl(NFS4_OK);
53 }
54 
55 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
56 {
57 	return xdr_argsize_check(rqstp, p);
58 }
59 
60 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
61 {
62 	return xdr_ressize_check(rqstp, p);
63 }
64 
65 static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
66 {
67 	__be32 *p;
68 
69 	p = xdr_inline_decode(xdr, nbytes);
70 	if (unlikely(p == NULL))
71 		printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
72 	return p;
73 }
74 
75 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
76 {
77 	__be32 *p;
78 
79 	p = read_buf(xdr, 4);
80 	if (unlikely(p == NULL))
81 		return htonl(NFS4ERR_RESOURCE);
82 	*len = ntohl(*p);
83 
84 	if (*len != 0) {
85 		p = read_buf(xdr, *len);
86 		if (unlikely(p == NULL))
87 			return htonl(NFS4ERR_RESOURCE);
88 		*str = (const char *)p;
89 	} else
90 		*str = NULL;
91 
92 	return 0;
93 }
94 
95 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
96 {
97 	__be32 *p;
98 
99 	p = read_buf(xdr, 4);
100 	if (unlikely(p == NULL))
101 		return htonl(NFS4ERR_RESOURCE);
102 	fh->size = ntohl(*p);
103 	if (fh->size > NFS4_FHSIZE)
104 		return htonl(NFS4ERR_BADHANDLE);
105 	p = read_buf(xdr, fh->size);
106 	if (unlikely(p == NULL))
107 		return htonl(NFS4ERR_RESOURCE);
108 	memcpy(&fh->data[0], p, fh->size);
109 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
110 	return 0;
111 }
112 
113 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
114 {
115 	__be32 *p;
116 	unsigned int attrlen;
117 
118 	p = read_buf(xdr, 4);
119 	if (unlikely(p == NULL))
120 		return htonl(NFS4ERR_RESOURCE);
121 	attrlen = ntohl(*p);
122 	p = read_buf(xdr, attrlen << 2);
123 	if (unlikely(p == NULL))
124 		return htonl(NFS4ERR_RESOURCE);
125 	if (likely(attrlen > 0))
126 		bitmap[0] = ntohl(*p++);
127 	if (attrlen > 1)
128 		bitmap[1] = ntohl(*p);
129 	return 0;
130 }
131 
132 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
133 {
134 	__be32 *p;
135 
136 	p = read_buf(xdr, 16);
137 	if (unlikely(p == NULL))
138 		return htonl(NFS4ERR_RESOURCE);
139 	memcpy(stateid->data, p, 16);
140 	return 0;
141 }
142 
143 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
144 {
145 	__be32 *p;
146 	__be32 status;
147 
148 	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
149 	if (unlikely(status != 0))
150 		return status;
151 	/* We do not like overly long tags! */
152 	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
153 		printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
154 				__func__, hdr->taglen);
155 		return htonl(NFS4ERR_RESOURCE);
156 	}
157 	p = read_buf(xdr, 12);
158 	if (unlikely(p == NULL))
159 		return htonl(NFS4ERR_RESOURCE);
160 	hdr->minorversion = ntohl(*p++);
161 	/* Check minor version is zero or one. */
162 	if (hdr->minorversion <= 1) {
163 		p++;	/* skip callback_ident */
164 	} else {
165 		printk(KERN_WARNING "%s: NFSv4 server callback with "
166 			"illegal minor version %u!\n",
167 			__func__, hdr->minorversion);
168 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
169 	}
170 	hdr->nops = ntohl(*p);
171 	dprintk("%s: minorversion %d nops %d\n", __func__,
172 		hdr->minorversion, hdr->nops);
173 	return 0;
174 }
175 
176 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
177 {
178 	__be32 *p;
179 	p = read_buf(xdr, 4);
180 	if (unlikely(p == NULL))
181 		return htonl(NFS4ERR_RESOURCE_HDR);
182 	*op = ntohl(*p);
183 	return 0;
184 }
185 
186 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
187 {
188 	__be32 status;
189 
190 	status = decode_fh(xdr, &args->fh);
191 	if (unlikely(status != 0))
192 		goto out;
193 	args->addr = svc_addr(rqstp);
194 	status = decode_bitmap(xdr, args->bitmap);
195 out:
196 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
197 	return status;
198 }
199 
200 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
201 {
202 	__be32 *p;
203 	__be32 status;
204 
205 	args->addr = svc_addr(rqstp);
206 	status = decode_stateid(xdr, &args->stateid);
207 	if (unlikely(status != 0))
208 		goto out;
209 	p = read_buf(xdr, 4);
210 	if (unlikely(p == NULL)) {
211 		status = htonl(NFS4ERR_RESOURCE);
212 		goto out;
213 	}
214 	args->truncate = ntohl(*p);
215 	status = decode_fh(xdr, &args->fh);
216 out:
217 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
218 	return status;
219 }
220 
221 #if defined(CONFIG_NFS_V4_1)
222 
223 static __be32 decode_sessionid(struct xdr_stream *xdr,
224 				 struct nfs4_sessionid *sid)
225 {
226 	__be32 *p;
227 	int len = NFS4_MAX_SESSIONID_LEN;
228 
229 	p = read_buf(xdr, len);
230 	if (unlikely(p == NULL))
231 		return htonl(NFS4ERR_RESOURCE);
232 
233 	memcpy(sid->data, p, len);
234 	return 0;
235 }
236 
237 static __be32 decode_rc_list(struct xdr_stream *xdr,
238 			       struct referring_call_list *rc_list)
239 {
240 	__be32 *p;
241 	int i;
242 	__be32 status;
243 
244 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
245 	if (status)
246 		goto out;
247 
248 	status = htonl(NFS4ERR_RESOURCE);
249 	p = read_buf(xdr, sizeof(uint32_t));
250 	if (unlikely(p == NULL))
251 		goto out;
252 
253 	rc_list->rcl_nrefcalls = ntohl(*p++);
254 	if (rc_list->rcl_nrefcalls) {
255 		p = read_buf(xdr,
256 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
257 		if (unlikely(p == NULL))
258 			goto out;
259 		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
260 						sizeof(*rc_list->rcl_refcalls),
261 						GFP_KERNEL);
262 		if (unlikely(rc_list->rcl_refcalls == NULL))
263 			goto out;
264 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
265 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
266 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
267 		}
268 	}
269 	status = 0;
270 
271 out:
272 	return status;
273 }
274 
275 static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
276 					struct xdr_stream *xdr,
277 					struct cb_sequenceargs *args)
278 {
279 	__be32 *p;
280 	int i;
281 	__be32 status;
282 
283 	status = decode_sessionid(xdr, &args->csa_sessionid);
284 	if (status)
285 		goto out;
286 
287 	status = htonl(NFS4ERR_RESOURCE);
288 	p = read_buf(xdr, 5 * sizeof(uint32_t));
289 	if (unlikely(p == NULL))
290 		goto out;
291 
292 	args->csa_addr = svc_addr(rqstp);
293 	args->csa_sequenceid = ntohl(*p++);
294 	args->csa_slotid = ntohl(*p++);
295 	args->csa_highestslotid = ntohl(*p++);
296 	args->csa_cachethis = ntohl(*p++);
297 	args->csa_nrclists = ntohl(*p++);
298 	args->csa_rclists = NULL;
299 	if (args->csa_nrclists) {
300 		args->csa_rclists = kmalloc(args->csa_nrclists *
301 					    sizeof(*args->csa_rclists),
302 					    GFP_KERNEL);
303 		if (unlikely(args->csa_rclists == NULL))
304 			goto out;
305 
306 		for (i = 0; i < args->csa_nrclists; i++) {
307 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
308 			if (status)
309 				goto out_free;
310 		}
311 	}
312 	status = 0;
313 
314 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
315 		"highestslotid %u cachethis %d nrclists %u\n",
316 		__func__,
317 		((u32 *)&args->csa_sessionid)[0],
318 		((u32 *)&args->csa_sessionid)[1],
319 		((u32 *)&args->csa_sessionid)[2],
320 		((u32 *)&args->csa_sessionid)[3],
321 		args->csa_sequenceid, args->csa_slotid,
322 		args->csa_highestslotid, args->csa_cachethis,
323 		args->csa_nrclists);
324 out:
325 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
326 	return status;
327 
328 out_free:
329 	for (i = 0; i < args->csa_nrclists; i++)
330 		kfree(args->csa_rclists[i].rcl_refcalls);
331 	kfree(args->csa_rclists);
332 	goto out;
333 }
334 
335 static __be32 decode_recallany_args(struct svc_rqst *rqstp,
336 				      struct xdr_stream *xdr,
337 				      struct cb_recallanyargs *args)
338 {
339 	__be32 *p;
340 
341 	args->craa_addr = svc_addr(rqstp);
342 	p = read_buf(xdr, 4);
343 	if (unlikely(p == NULL))
344 		return htonl(NFS4ERR_BADXDR);
345 	args->craa_objs_to_keep = ntohl(*p++);
346 	p = read_buf(xdr, 4);
347 	if (unlikely(p == NULL))
348 		return htonl(NFS4ERR_BADXDR);
349 	args->craa_type_mask = ntohl(*p);
350 
351 	return 0;
352 }
353 
354 static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
355 					struct xdr_stream *xdr,
356 					struct cb_recallslotargs *args)
357 {
358 	__be32 *p;
359 
360 	args->crsa_addr = svc_addr(rqstp);
361 	p = read_buf(xdr, 4);
362 	if (unlikely(p == NULL))
363 		return htonl(NFS4ERR_BADXDR);
364 	args->crsa_target_max_slots = ntohl(*p++);
365 	return 0;
366 }
367 
368 #endif /* CONFIG_NFS_V4_1 */
369 
370 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
371 {
372 	__be32 *p;
373 
374 	p = xdr_reserve_space(xdr, 4 + len);
375 	if (unlikely(p == NULL))
376 		return htonl(NFS4ERR_RESOURCE);
377 	xdr_encode_opaque(p, str, len);
378 	return 0;
379 }
380 
381 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
382 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
383 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
384 {
385 	__be32 bm[2];
386 	__be32 *p;
387 
388 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
389 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
390 	if (bm[1] != 0) {
391 		p = xdr_reserve_space(xdr, 16);
392 		if (unlikely(p == NULL))
393 			return htonl(NFS4ERR_RESOURCE);
394 		*p++ = htonl(2);
395 		*p++ = bm[0];
396 		*p++ = bm[1];
397 	} else if (bm[0] != 0) {
398 		p = xdr_reserve_space(xdr, 12);
399 		if (unlikely(p == NULL))
400 			return htonl(NFS4ERR_RESOURCE);
401 		*p++ = htonl(1);
402 		*p++ = bm[0];
403 	} else {
404 		p = xdr_reserve_space(xdr, 8);
405 		if (unlikely(p == NULL))
406 			return htonl(NFS4ERR_RESOURCE);
407 		*p++ = htonl(0);
408 	}
409 	*savep = p;
410 	return 0;
411 }
412 
413 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
414 {
415 	__be32 *p;
416 
417 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
418 		return 0;
419 	p = xdr_reserve_space(xdr, 8);
420 	if (unlikely(!p))
421 		return htonl(NFS4ERR_RESOURCE);
422 	p = xdr_encode_hyper(p, change);
423 	return 0;
424 }
425 
426 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
427 {
428 	__be32 *p;
429 
430 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
431 		return 0;
432 	p = xdr_reserve_space(xdr, 8);
433 	if (unlikely(!p))
434 		return htonl(NFS4ERR_RESOURCE);
435 	p = xdr_encode_hyper(p, size);
436 	return 0;
437 }
438 
439 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
440 {
441 	__be32 *p;
442 
443 	p = xdr_reserve_space(xdr, 12);
444 	if (unlikely(!p))
445 		return htonl(NFS4ERR_RESOURCE);
446 	p = xdr_encode_hyper(p, time->tv_sec);
447 	*p = htonl(time->tv_nsec);
448 	return 0;
449 }
450 
451 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
452 {
453 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
454 		return 0;
455 	return encode_attr_time(xdr,time);
456 }
457 
458 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
459 {
460 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
461 		return 0;
462 	return encode_attr_time(xdr,time);
463 }
464 
465 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
466 {
467 	__be32 status;
468 
469 	hdr->status = xdr_reserve_space(xdr, 4);
470 	if (unlikely(hdr->status == NULL))
471 		return htonl(NFS4ERR_RESOURCE);
472 	status = encode_string(xdr, hdr->taglen, hdr->tag);
473 	if (unlikely(status != 0))
474 		return status;
475 	hdr->nops = xdr_reserve_space(xdr, 4);
476 	if (unlikely(hdr->nops == NULL))
477 		return htonl(NFS4ERR_RESOURCE);
478 	return 0;
479 }
480 
481 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
482 {
483 	__be32 *p;
484 
485 	p = xdr_reserve_space(xdr, 8);
486 	if (unlikely(p == NULL))
487 		return htonl(NFS4ERR_RESOURCE_HDR);
488 	*p++ = htonl(op);
489 	*p = res;
490 	return 0;
491 }
492 
493 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
494 {
495 	__be32 *savep = NULL;
496 	__be32 status = res->status;
497 
498 	if (unlikely(status != 0))
499 		goto out;
500 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
501 	if (unlikely(status != 0))
502 		goto out;
503 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
504 	if (unlikely(status != 0))
505 		goto out;
506 	status = encode_attr_size(xdr, res->bitmap, res->size);
507 	if (unlikely(status != 0))
508 		goto out;
509 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
510 	if (unlikely(status != 0))
511 		goto out;
512 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
513 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
514 out:
515 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
516 	return status;
517 }
518 
519 #if defined(CONFIG_NFS_V4_1)
520 
521 static __be32 encode_sessionid(struct xdr_stream *xdr,
522 				 const struct nfs4_sessionid *sid)
523 {
524 	__be32 *p;
525 	int len = NFS4_MAX_SESSIONID_LEN;
526 
527 	p = xdr_reserve_space(xdr, len);
528 	if (unlikely(p == NULL))
529 		return htonl(NFS4ERR_RESOURCE);
530 
531 	memcpy(p, sid, len);
532 	return 0;
533 }
534 
535 static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
536 				       struct xdr_stream *xdr,
537 				       const struct cb_sequenceres *res)
538 {
539 	__be32 *p;
540 	unsigned status = res->csr_status;
541 
542 	if (unlikely(status != 0))
543 		goto out;
544 
545 	encode_sessionid(xdr, &res->csr_sessionid);
546 
547 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
548 	if (unlikely(p == NULL))
549 		return htonl(NFS4ERR_RESOURCE);
550 
551 	*p++ = htonl(res->csr_sequenceid);
552 	*p++ = htonl(res->csr_slotid);
553 	*p++ = htonl(res->csr_highestslotid);
554 	*p++ = htonl(res->csr_target_highestslotid);
555 out:
556 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
557 	return status;
558 }
559 
560 static __be32
561 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
562 {
563 	if (op_nr == OP_CB_SEQUENCE) {
564 		if (nop != 0)
565 			return htonl(NFS4ERR_SEQUENCE_POS);
566 	} else {
567 		if (nop == 0)
568 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
569 	}
570 
571 	switch (op_nr) {
572 	case OP_CB_GETATTR:
573 	case OP_CB_RECALL:
574 	case OP_CB_SEQUENCE:
575 	case OP_CB_RECALL_ANY:
576 	case OP_CB_RECALL_SLOT:
577 		*op = &callback_ops[op_nr];
578 		break;
579 
580 	case OP_CB_LAYOUTRECALL:
581 	case OP_CB_NOTIFY_DEVICEID:
582 	case OP_CB_NOTIFY:
583 	case OP_CB_PUSH_DELEG:
584 	case OP_CB_RECALLABLE_OBJ_AVAIL:
585 	case OP_CB_WANTS_CANCELLED:
586 	case OP_CB_NOTIFY_LOCK:
587 		return htonl(NFS4ERR_NOTSUPP);
588 
589 	default:
590 		return htonl(NFS4ERR_OP_ILLEGAL);
591 	}
592 
593 	return htonl(NFS_OK);
594 }
595 
596 #else /* CONFIG_NFS_V4_1 */
597 
598 static __be32
599 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
600 {
601 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
602 }
603 
604 #endif /* CONFIG_NFS_V4_1 */
605 
606 static __be32
607 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
608 {
609 	switch (op_nr) {
610 	case OP_CB_GETATTR:
611 	case OP_CB_RECALL:
612 		*op = &callback_ops[op_nr];
613 		break;
614 	default:
615 		return htonl(NFS4ERR_OP_ILLEGAL);
616 	}
617 
618 	return htonl(NFS_OK);
619 }
620 
621 static __be32 process_op(uint32_t minorversion, int nop,
622 		struct svc_rqst *rqstp,
623 		struct xdr_stream *xdr_in, void *argp,
624 		struct xdr_stream *xdr_out, void *resp, int* drc_status)
625 {
626 	struct callback_op *op = &callback_ops[0];
627 	unsigned int op_nr;
628 	__be32 status;
629 	long maxlen;
630 	__be32 res;
631 
632 	dprintk("%s: start\n", __func__);
633 	status = decode_op_hdr(xdr_in, &op_nr);
634 	if (unlikely(status))
635 		return status;
636 
637 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
638 		__func__, minorversion, nop, op_nr);
639 
640 	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
641 				preprocess_nfs4_op(op_nr, &op);
642 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
643 		op_nr = OP_CB_ILLEGAL;
644 	if (status)
645 		goto encode_hdr;
646 
647 	if (*drc_status) {
648 		status = *drc_status;
649 		goto encode_hdr;
650 	}
651 
652 	maxlen = xdr_out->end - xdr_out->p;
653 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
654 		status = op->decode_args(rqstp, xdr_in, argp);
655 		if (likely(status == 0))
656 			status = op->process_op(argp, resp);
657 	} else
658 		status = htonl(NFS4ERR_RESOURCE);
659 
660 	/* Only set by OP_CB_SEQUENCE processing */
661 	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
662 		*drc_status = status;
663 		status = 0;
664 	}
665 
666 encode_hdr:
667 	res = encode_op_hdr(xdr_out, op_nr, status);
668 	if (unlikely(res))
669 		return res;
670 	if (op->encode_res != NULL && status == 0)
671 		status = op->encode_res(rqstp, xdr_out, resp);
672 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
673 	return status;
674 }
675 
676 /*
677  * Decode, process and encode a COMPOUND
678  */
679 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
680 {
681 	struct cb_compound_hdr_arg hdr_arg = { 0 };
682 	struct cb_compound_hdr_res hdr_res = { NULL };
683 	struct xdr_stream xdr_in, xdr_out;
684 	__be32 *p;
685 	__be32 status, drc_status = 0;
686 	unsigned int nops = 0;
687 
688 	dprintk("%s: start\n", __func__);
689 
690 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
691 
692 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
693 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
694 
695 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
696 	if (status == __constant_htonl(NFS4ERR_RESOURCE))
697 		return rpc_garbage_args;
698 
699 	hdr_res.taglen = hdr_arg.taglen;
700 	hdr_res.tag = hdr_arg.tag;
701 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
702 		return rpc_system_err;
703 
704 	while (status == 0 && nops != hdr_arg.nops) {
705 		status = process_op(hdr_arg.minorversion, nops, rqstp,
706 				    &xdr_in, argp, &xdr_out, resp, &drc_status);
707 		nops++;
708 	}
709 
710 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
711 	* resource error in cb_compound status without returning op */
712 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
713 		status = htonl(NFS4ERR_RESOURCE);
714 		nops--;
715 	}
716 
717 	*hdr_res.status = status;
718 	*hdr_res.nops = htonl(nops);
719 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
720 	return rpc_success;
721 }
722 
723 /*
724  * Define NFS4 callback COMPOUND ops.
725  */
726 static struct callback_op callback_ops[] = {
727 	[0] = {
728 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
729 	},
730 	[OP_CB_GETATTR] = {
731 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
732 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
733 		.encode_res = (callback_encode_res_t)encode_getattr_res,
734 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
735 	},
736 	[OP_CB_RECALL] = {
737 		.process_op = (callback_process_op_t)nfs4_callback_recall,
738 		.decode_args = (callback_decode_arg_t)decode_recall_args,
739 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
740 	},
741 #if defined(CONFIG_NFS_V4_1)
742 	[OP_CB_SEQUENCE] = {
743 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
744 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
745 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
746 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
747 	},
748 	[OP_CB_RECALL_ANY] = {
749 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
750 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
751 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
752 	},
753 	[OP_CB_RECALL_SLOT] = {
754 		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
755 		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
756 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
757 	},
758 #endif /* CONFIG_NFS_V4_1 */
759 };
760 
761 /*
762  * Define NFS4 callback procedures
763  */
764 static struct svc_procedure nfs4_callback_procedures1[] = {
765 	[CB_NULL] = {
766 		.pc_func = nfs4_callback_null,
767 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
768 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
769 		.pc_xdrressize = 1,
770 	},
771 	[CB_COMPOUND] = {
772 		.pc_func = nfs4_callback_compound,
773 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
774 		.pc_argsize = 256,
775 		.pc_ressize = 256,
776 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
777 	}
778 };
779 
780 struct svc_version nfs4_callback_version1 = {
781 	.vs_vers = 1,
782 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
783 	.vs_proc = nfs4_callback_procedures1,
784 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
785 	.vs_dispatch = NULL,
786 	.vs_hidden = 1,
787 };
788 
789 struct svc_version nfs4_callback_version4 = {
790 	.vs_vers = 4,
791 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
792 	.vs_proc = nfs4_callback_procedures1,
793 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
794 	.vs_dispatch = NULL,
795 };
796