xref: /openbmc/linux/fs/nfs/callback_xdr.c (revision b9efa1b27e25b1286504973c0a6bf0f24106faa8)
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 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
28 #endif /* CONFIG_NFS_V4_1 */
29 
30 #define NFSDBG_FACILITY NFSDBG_CALLBACK
31 
32 /* Internal error code */
33 #define NFS4ERR_RESOURCE_HDR	11050
34 
35 typedef __be32 (*callback_process_op_t)(void *, void *);
36 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
37 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
38 
39 
40 struct callback_op {
41 	callback_process_op_t process_op;
42 	callback_decode_arg_t decode_args;
43 	callback_encode_res_t encode_res;
44 	long res_maxsize;
45 };
46 
47 static struct callback_op callback_ops[];
48 
49 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
50 {
51 	return htonl(NFS4_OK);
52 }
53 
54 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
55 {
56 	return xdr_argsize_check(rqstp, p);
57 }
58 
59 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
60 {
61 	return xdr_ressize_check(rqstp, p);
62 }
63 
64 static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
65 {
66 	__be32 *p;
67 
68 	p = xdr_inline_decode(xdr, nbytes);
69 	if (unlikely(p == NULL))
70 		printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
71 	return p;
72 }
73 
74 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
75 {
76 	__be32 *p;
77 
78 	p = read_buf(xdr, 4);
79 	if (unlikely(p == NULL))
80 		return htonl(NFS4ERR_RESOURCE);
81 	*len = ntohl(*p);
82 
83 	if (*len != 0) {
84 		p = read_buf(xdr, *len);
85 		if (unlikely(p == NULL))
86 			return htonl(NFS4ERR_RESOURCE);
87 		*str = (const char *)p;
88 	} else
89 		*str = NULL;
90 
91 	return 0;
92 }
93 
94 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
95 {
96 	__be32 *p;
97 
98 	p = read_buf(xdr, 4);
99 	if (unlikely(p == NULL))
100 		return htonl(NFS4ERR_RESOURCE);
101 	fh->size = ntohl(*p);
102 	if (fh->size > NFS4_FHSIZE)
103 		return htonl(NFS4ERR_BADHANDLE);
104 	p = read_buf(xdr, fh->size);
105 	if (unlikely(p == NULL))
106 		return htonl(NFS4ERR_RESOURCE);
107 	memcpy(&fh->data[0], p, fh->size);
108 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
109 	return 0;
110 }
111 
112 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
113 {
114 	__be32 *p;
115 	unsigned int attrlen;
116 
117 	p = read_buf(xdr, 4);
118 	if (unlikely(p == NULL))
119 		return htonl(NFS4ERR_RESOURCE);
120 	attrlen = ntohl(*p);
121 	p = read_buf(xdr, attrlen << 2);
122 	if (unlikely(p == NULL))
123 		return htonl(NFS4ERR_RESOURCE);
124 	if (likely(attrlen > 0))
125 		bitmap[0] = ntohl(*p++);
126 	if (attrlen > 1)
127 		bitmap[1] = ntohl(*p);
128 	return 0;
129 }
130 
131 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
132 {
133 	__be32 *p;
134 
135 	p = read_buf(xdr, 16);
136 	if (unlikely(p == NULL))
137 		return htonl(NFS4ERR_RESOURCE);
138 	memcpy(stateid->data, p, 16);
139 	return 0;
140 }
141 
142 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
143 {
144 	__be32 *p;
145 	__be32 status;
146 
147 	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
148 	if (unlikely(status != 0))
149 		return status;
150 	/* We do not like overly long tags! */
151 	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
152 		printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
153 				__func__, hdr->taglen);
154 		return htonl(NFS4ERR_RESOURCE);
155 	}
156 	p = read_buf(xdr, 12);
157 	if (unlikely(p == NULL))
158 		return htonl(NFS4ERR_RESOURCE);
159 	hdr->minorversion = ntohl(*p++);
160 	/* Check minor version is zero or one. */
161 	if (hdr->minorversion <= 1) {
162 		p++;	/* skip callback_ident */
163 	} else {
164 		printk(KERN_WARNING "%s: NFSv4 server callback with "
165 			"illegal minor version %u!\n",
166 			__func__, hdr->minorversion);
167 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
168 	}
169 	hdr->nops = ntohl(*p);
170 	dprintk("%s: minorversion %d nops %d\n", __func__,
171 		hdr->minorversion, hdr->nops);
172 	return 0;
173 }
174 
175 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
176 {
177 	__be32 *p;
178 	p = read_buf(xdr, 4);
179 	if (unlikely(p == NULL))
180 		return htonl(NFS4ERR_RESOURCE_HDR);
181 	*op = ntohl(*p);
182 	return 0;
183 }
184 
185 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
186 {
187 	__be32 status;
188 
189 	status = decode_fh(xdr, &args->fh);
190 	if (unlikely(status != 0))
191 		goto out;
192 	args->addr = svc_addr(rqstp);
193 	status = decode_bitmap(xdr, args->bitmap);
194 out:
195 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
196 	return status;
197 }
198 
199 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
200 {
201 	__be32 *p;
202 	__be32 status;
203 
204 	args->addr = svc_addr(rqstp);
205 	status = decode_stateid(xdr, &args->stateid);
206 	if (unlikely(status != 0))
207 		goto out;
208 	p = read_buf(xdr, 4);
209 	if (unlikely(p == NULL)) {
210 		status = htonl(NFS4ERR_RESOURCE);
211 		goto out;
212 	}
213 	args->truncate = ntohl(*p);
214 	status = decode_fh(xdr, &args->fh);
215 out:
216 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
217 	return status;
218 }
219 
220 #if defined(CONFIG_NFS_V4_1)
221 
222 static unsigned decode_sessionid(struct xdr_stream *xdr,
223 				 struct nfs4_sessionid *sid)
224 {
225 	uint32_t *p;
226 	int len = NFS4_MAX_SESSIONID_LEN;
227 
228 	p = read_buf(xdr, len);
229 	if (unlikely(p == NULL))
230 		return htonl(NFS4ERR_RESOURCE);
231 
232 	memcpy(sid->data, p, len);
233 	return 0;
234 }
235 
236 static unsigned decode_rc_list(struct xdr_stream *xdr,
237 			       struct referring_call_list *rc_list)
238 {
239 	uint32_t *p;
240 	int i;
241 	unsigned status;
242 
243 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
244 	if (status)
245 		goto out;
246 
247 	status = htonl(NFS4ERR_RESOURCE);
248 	p = read_buf(xdr, sizeof(uint32_t));
249 	if (unlikely(p == NULL))
250 		goto out;
251 
252 	rc_list->rcl_nrefcalls = ntohl(*p++);
253 	if (rc_list->rcl_nrefcalls) {
254 		p = read_buf(xdr,
255 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
256 		if (unlikely(p == NULL))
257 			goto out;
258 		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
259 						sizeof(*rc_list->rcl_refcalls),
260 						GFP_KERNEL);
261 		if (unlikely(rc_list->rcl_refcalls == NULL))
262 			goto out;
263 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
264 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
265 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
266 		}
267 	}
268 	status = 0;
269 
270 out:
271 	return status;
272 }
273 
274 static unsigned decode_cb_sequence_args(struct svc_rqst *rqstp,
275 					struct xdr_stream *xdr,
276 					struct cb_sequenceargs *args)
277 {
278 	uint32_t *p;
279 	int i;
280 	unsigned status;
281 
282 	status = decode_sessionid(xdr, &args->csa_sessionid);
283 	if (status)
284 		goto out;
285 
286 	status = htonl(NFS4ERR_RESOURCE);
287 	p = read_buf(xdr, 5 * sizeof(uint32_t));
288 	if (unlikely(p == NULL))
289 		goto out;
290 
291 	args->csa_addr = svc_addr(rqstp);
292 	args->csa_sequenceid = ntohl(*p++);
293 	args->csa_slotid = ntohl(*p++);
294 	args->csa_highestslotid = ntohl(*p++);
295 	args->csa_cachethis = ntohl(*p++);
296 	args->csa_nrclists = ntohl(*p++);
297 	args->csa_rclists = NULL;
298 	if (args->csa_nrclists) {
299 		args->csa_rclists = kmalloc(args->csa_nrclists *
300 					    sizeof(*args->csa_rclists),
301 					    GFP_KERNEL);
302 		if (unlikely(args->csa_rclists == NULL))
303 			goto out;
304 
305 		for (i = 0; i < args->csa_nrclists; i++) {
306 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
307 			if (status)
308 				goto out_free;
309 		}
310 	}
311 	status = 0;
312 
313 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
314 		"highestslotid %u cachethis %d nrclists %u\n",
315 		__func__,
316 		((u32 *)&args->csa_sessionid)[0],
317 		((u32 *)&args->csa_sessionid)[1],
318 		((u32 *)&args->csa_sessionid)[2],
319 		((u32 *)&args->csa_sessionid)[3],
320 		args->csa_sequenceid, args->csa_slotid,
321 		args->csa_highestslotid, args->csa_cachethis,
322 		args->csa_nrclists);
323 out:
324 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
325 	return status;
326 
327 out_free:
328 	for (i = 0; i < args->csa_nrclists; i++)
329 		kfree(args->csa_rclists[i].rcl_refcalls);
330 	kfree(args->csa_rclists);
331 	goto out;
332 }
333 
334 static unsigned decode_recallany_args(struct svc_rqst *rqstp,
335 				      struct xdr_stream *xdr,
336 				      struct cb_recallanyargs *args)
337 {
338 	uint32_t *p;
339 
340 	args->craa_addr = svc_addr(rqstp);
341 	p = read_buf(xdr, 4);
342 	if (unlikely(p == NULL))
343 		return htonl(NFS4ERR_BADXDR);
344 	args->craa_objs_to_keep = ntohl(*p++);
345 	p = read_buf(xdr, 4);
346 	if (unlikely(p == NULL))
347 		return htonl(NFS4ERR_BADXDR);
348 	args->craa_type_mask = ntohl(*p);
349 
350 	return 0;
351 }
352 
353 static unsigned decode_recallslot_args(struct svc_rqst *rqstp,
354 					struct xdr_stream *xdr,
355 					struct cb_recallslotargs *args)
356 {
357 	__be32 *p;
358 
359 	args->crsa_addr = svc_addr(rqstp);
360 	p = read_buf(xdr, 4);
361 	if (unlikely(p == NULL))
362 		return htonl(NFS4ERR_BADXDR);
363 	args->crsa_target_max_slots = ntohl(*p++);
364 	return 0;
365 }
366 
367 #endif /* CONFIG_NFS_V4_1 */
368 
369 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
370 {
371 	__be32 *p;
372 
373 	p = xdr_reserve_space(xdr, 4 + len);
374 	if (unlikely(p == NULL))
375 		return htonl(NFS4ERR_RESOURCE);
376 	xdr_encode_opaque(p, str, len);
377 	return 0;
378 }
379 
380 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
381 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
382 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
383 {
384 	__be32 bm[2];
385 	__be32 *p;
386 
387 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
388 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
389 	if (bm[1] != 0) {
390 		p = xdr_reserve_space(xdr, 16);
391 		if (unlikely(p == NULL))
392 			return htonl(NFS4ERR_RESOURCE);
393 		*p++ = htonl(2);
394 		*p++ = bm[0];
395 		*p++ = bm[1];
396 	} else if (bm[0] != 0) {
397 		p = xdr_reserve_space(xdr, 12);
398 		if (unlikely(p == NULL))
399 			return htonl(NFS4ERR_RESOURCE);
400 		*p++ = htonl(1);
401 		*p++ = bm[0];
402 	} else {
403 		p = xdr_reserve_space(xdr, 8);
404 		if (unlikely(p == NULL))
405 			return htonl(NFS4ERR_RESOURCE);
406 		*p++ = htonl(0);
407 	}
408 	*savep = p;
409 	return 0;
410 }
411 
412 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
413 {
414 	__be32 *p;
415 
416 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
417 		return 0;
418 	p = xdr_reserve_space(xdr, 8);
419 	if (unlikely(!p))
420 		return htonl(NFS4ERR_RESOURCE);
421 	p = xdr_encode_hyper(p, change);
422 	return 0;
423 }
424 
425 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
426 {
427 	__be32 *p;
428 
429 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
430 		return 0;
431 	p = xdr_reserve_space(xdr, 8);
432 	if (unlikely(!p))
433 		return htonl(NFS4ERR_RESOURCE);
434 	p = xdr_encode_hyper(p, size);
435 	return 0;
436 }
437 
438 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
439 {
440 	__be32 *p;
441 
442 	p = xdr_reserve_space(xdr, 12);
443 	if (unlikely(!p))
444 		return htonl(NFS4ERR_RESOURCE);
445 	p = xdr_encode_hyper(p, time->tv_sec);
446 	*p = htonl(time->tv_nsec);
447 	return 0;
448 }
449 
450 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
451 {
452 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
453 		return 0;
454 	return encode_attr_time(xdr,time);
455 }
456 
457 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
458 {
459 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
460 		return 0;
461 	return encode_attr_time(xdr,time);
462 }
463 
464 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
465 {
466 	__be32 status;
467 
468 	hdr->status = xdr_reserve_space(xdr, 4);
469 	if (unlikely(hdr->status == NULL))
470 		return htonl(NFS4ERR_RESOURCE);
471 	status = encode_string(xdr, hdr->taglen, hdr->tag);
472 	if (unlikely(status != 0))
473 		return status;
474 	hdr->nops = xdr_reserve_space(xdr, 4);
475 	if (unlikely(hdr->nops == NULL))
476 		return htonl(NFS4ERR_RESOURCE);
477 	return 0;
478 }
479 
480 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
481 {
482 	__be32 *p;
483 
484 	p = xdr_reserve_space(xdr, 8);
485 	if (unlikely(p == NULL))
486 		return htonl(NFS4ERR_RESOURCE_HDR);
487 	*p++ = htonl(op);
488 	*p = res;
489 	return 0;
490 }
491 
492 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
493 {
494 	__be32 *savep = NULL;
495 	__be32 status = res->status;
496 
497 	if (unlikely(status != 0))
498 		goto out;
499 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
500 	if (unlikely(status != 0))
501 		goto out;
502 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
503 	if (unlikely(status != 0))
504 		goto out;
505 	status = encode_attr_size(xdr, res->bitmap, res->size);
506 	if (unlikely(status != 0))
507 		goto out;
508 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
509 	if (unlikely(status != 0))
510 		goto out;
511 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
512 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
513 out:
514 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
515 	return status;
516 }
517 
518 #if defined(CONFIG_NFS_V4_1)
519 
520 static unsigned encode_sessionid(struct xdr_stream *xdr,
521 				 const struct nfs4_sessionid *sid)
522 {
523 	uint32_t *p;
524 	int len = NFS4_MAX_SESSIONID_LEN;
525 
526 	p = xdr_reserve_space(xdr, len);
527 	if (unlikely(p == NULL))
528 		return htonl(NFS4ERR_RESOURCE);
529 
530 	memcpy(p, sid, len);
531 	return 0;
532 }
533 
534 static unsigned encode_cb_sequence_res(struct svc_rqst *rqstp,
535 				       struct xdr_stream *xdr,
536 				       const struct cb_sequenceres *res)
537 {
538 	uint32_t *p;
539 	unsigned status = res->csr_status;
540 
541 	if (unlikely(status != 0))
542 		goto out;
543 
544 	encode_sessionid(xdr, &res->csr_sessionid);
545 
546 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
547 	if (unlikely(p == NULL))
548 		return htonl(NFS4ERR_RESOURCE);
549 
550 	*p++ = htonl(res->csr_sequenceid);
551 	*p++ = htonl(res->csr_slotid);
552 	*p++ = htonl(res->csr_highestslotid);
553 	*p++ = htonl(res->csr_target_highestslotid);
554 out:
555 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
556 	return status;
557 }
558 
559 static __be32
560 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
561 {
562 	if (op_nr == OP_CB_SEQUENCE) {
563 		if (nop != 0)
564 			return htonl(NFS4ERR_SEQUENCE_POS);
565 	} else {
566 		if (nop == 0)
567 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
568 	}
569 
570 	switch (op_nr) {
571 	case OP_CB_GETATTR:
572 	case OP_CB_RECALL:
573 	case OP_CB_SEQUENCE:
574 	case OP_CB_RECALL_ANY:
575 	case OP_CB_RECALL_SLOT:
576 		*op = &callback_ops[op_nr];
577 		break;
578 
579 	case OP_CB_LAYOUTRECALL:
580 	case OP_CB_NOTIFY_DEVICEID:
581 	case OP_CB_NOTIFY:
582 	case OP_CB_PUSH_DELEG:
583 	case OP_CB_RECALLABLE_OBJ_AVAIL:
584 	case OP_CB_WANTS_CANCELLED:
585 	case OP_CB_NOTIFY_LOCK:
586 		return htonl(NFS4ERR_NOTSUPP);
587 
588 	default:
589 		return htonl(NFS4ERR_OP_ILLEGAL);
590 	}
591 
592 	return htonl(NFS_OK);
593 }
594 
595 #else /* CONFIG_NFS_V4_1 */
596 
597 static __be32
598 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
599 {
600 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
601 }
602 
603 #endif /* CONFIG_NFS_V4_1 */
604 
605 static __be32
606 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
607 {
608 	switch (op_nr) {
609 	case OP_CB_GETATTR:
610 	case OP_CB_RECALL:
611 		*op = &callback_ops[op_nr];
612 		break;
613 	default:
614 		return htonl(NFS4ERR_OP_ILLEGAL);
615 	}
616 
617 	return htonl(NFS_OK);
618 }
619 
620 static __be32 process_op(uint32_t minorversion, int nop,
621 		struct svc_rqst *rqstp,
622 		struct xdr_stream *xdr_in, void *argp,
623 		struct xdr_stream *xdr_out, void *resp, int* drc_status)
624 {
625 	struct callback_op *op = &callback_ops[0];
626 	unsigned int op_nr;
627 	__be32 status;
628 	long maxlen;
629 	__be32 res;
630 
631 	dprintk("%s: start\n", __func__);
632 	status = decode_op_hdr(xdr_in, &op_nr);
633 	if (unlikely(status))
634 		return status;
635 
636 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
637 		__func__, minorversion, nop, op_nr);
638 
639 	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
640 				preprocess_nfs4_op(op_nr, &op);
641 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
642 		op_nr = OP_CB_ILLEGAL;
643 	if (status)
644 		goto encode_hdr;
645 
646 	if (*drc_status) {
647 		status = *drc_status;
648 		goto encode_hdr;
649 	}
650 
651 	maxlen = xdr_out->end - xdr_out->p;
652 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
653 		status = op->decode_args(rqstp, xdr_in, argp);
654 		if (likely(status == 0))
655 			status = op->process_op(argp, resp);
656 	} else
657 		status = htonl(NFS4ERR_RESOURCE);
658 
659 	/* Only set by OP_CB_SEQUENCE processing */
660 	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
661 		*drc_status = status;
662 		status = 0;
663 	}
664 
665 encode_hdr:
666 	res = encode_op_hdr(xdr_out, op_nr, status);
667 	if (unlikely(res))
668 		return res;
669 	if (op->encode_res != NULL && status == 0)
670 		status = op->encode_res(rqstp, xdr_out, resp);
671 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
672 	return status;
673 }
674 
675 /*
676  * Decode, process and encode a COMPOUND
677  */
678 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
679 {
680 	struct cb_compound_hdr_arg hdr_arg = { 0 };
681 	struct cb_compound_hdr_res hdr_res = { NULL };
682 	struct xdr_stream xdr_in, xdr_out;
683 	__be32 *p;
684 	__be32 status, drc_status = 0;
685 	unsigned int nops = 0;
686 
687 	dprintk("%s: start\n", __func__);
688 
689 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
690 
691 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
692 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
693 
694 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
695 	if (status == __constant_htonl(NFS4ERR_RESOURCE))
696 		return rpc_garbage_args;
697 
698 	hdr_res.taglen = hdr_arg.taglen;
699 	hdr_res.tag = hdr_arg.tag;
700 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
701 		return rpc_system_err;
702 
703 	while (status == 0 && nops != hdr_arg.nops) {
704 		status = process_op(hdr_arg.minorversion, nops, rqstp,
705 				    &xdr_in, argp, &xdr_out, resp, &drc_status);
706 		nops++;
707 	}
708 
709 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
710 	* resource error in cb_compound status without returning op */
711 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
712 		status = htonl(NFS4ERR_RESOURCE);
713 		nops--;
714 	}
715 
716 	*hdr_res.status = status;
717 	*hdr_res.nops = htonl(nops);
718 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
719 	return rpc_success;
720 }
721 
722 /*
723  * Define NFS4 callback COMPOUND ops.
724  */
725 static struct callback_op callback_ops[] = {
726 	[0] = {
727 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
728 	},
729 	[OP_CB_GETATTR] = {
730 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
731 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
732 		.encode_res = (callback_encode_res_t)encode_getattr_res,
733 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
734 	},
735 	[OP_CB_RECALL] = {
736 		.process_op = (callback_process_op_t)nfs4_callback_recall,
737 		.decode_args = (callback_decode_arg_t)decode_recall_args,
738 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
739 	},
740 #if defined(CONFIG_NFS_V4_1)
741 	[OP_CB_SEQUENCE] = {
742 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
743 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
744 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
745 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
746 	},
747 	[OP_CB_RECALL_ANY] = {
748 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
749 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
750 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
751 	},
752 	[OP_CB_RECALL_SLOT] = {
753 		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
754 		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
755 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
756 	},
757 #endif /* CONFIG_NFS_V4_1 */
758 };
759 
760 /*
761  * Define NFS4 callback procedures
762  */
763 static struct svc_procedure nfs4_callback_procedures1[] = {
764 	[CB_NULL] = {
765 		.pc_func = nfs4_callback_null,
766 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
767 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
768 		.pc_xdrressize = 1,
769 	},
770 	[CB_COMPOUND] = {
771 		.pc_func = nfs4_callback_compound,
772 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
773 		.pc_argsize = 256,
774 		.pc_ressize = 256,
775 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
776 	}
777 };
778 
779 struct svc_version nfs4_callback_version1 = {
780 	.vs_vers = 1,
781 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
782 	.vs_proc = nfs4_callback_procedures1,
783 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
784 	.vs_dispatch = NULL,
785 };
786 
787 struct svc_version nfs4_callback_version4 = {
788 	.vs_vers = 4,
789 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
790 	.vs_proc = nfs4_callback_procedures1,
791 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
792 	.vs_dispatch = NULL,
793 };
794