xref: /linux/fs/nfs/callback_xdr.c (revision a67ff6a54095e27093ea501fb143fefe51a536c2)
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 <linux/sunrpc/bc_xprt.h>
14 #include "nfs4_fs.h"
15 #include "callback.h"
16 #include "internal.h"
17 
18 #define CB_OP_TAGLEN_MAXSZ	(512)
19 #define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
20 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
21 #define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
22 				CB_OP_GETATTR_BITMAP_MAXSZ + \
23 				2 + 2 + 3 + 3)
24 #define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
25 
26 #if defined(CONFIG_NFS_V4_1)
27 #define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
28 #define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
29 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
30 					4 + 1 + 3)
31 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
32 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
33 #endif /* CONFIG_NFS_V4_1 */
34 
35 #define NFSDBG_FACILITY NFSDBG_CALLBACK
36 
37 /* Internal error code */
38 #define NFS4ERR_RESOURCE_HDR	11050
39 
40 typedef __be32 (*callback_process_op_t)(void *, void *,
41 					struct cb_process_state *);
42 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
43 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
44 
45 
46 struct callback_op {
47 	callback_process_op_t process_op;
48 	callback_decode_arg_t decode_args;
49 	callback_encode_res_t encode_res;
50 	long res_maxsize;
51 };
52 
53 static struct callback_op callback_ops[];
54 
55 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
56 {
57 	return htonl(NFS4_OK);
58 }
59 
60 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
61 {
62 	return xdr_argsize_check(rqstp, p);
63 }
64 
65 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
66 {
67 	return xdr_ressize_check(rqstp, p);
68 }
69 
70 static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
71 {
72 	__be32 *p;
73 
74 	p = xdr_inline_decode(xdr, nbytes);
75 	if (unlikely(p == NULL))
76 		printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
77 	return p;
78 }
79 
80 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
81 {
82 	__be32 *p;
83 
84 	p = read_buf(xdr, 4);
85 	if (unlikely(p == NULL))
86 		return htonl(NFS4ERR_RESOURCE);
87 	*len = ntohl(*p);
88 
89 	if (*len != 0) {
90 		p = read_buf(xdr, *len);
91 		if (unlikely(p == NULL))
92 			return htonl(NFS4ERR_RESOURCE);
93 		*str = (const char *)p;
94 	} else
95 		*str = NULL;
96 
97 	return 0;
98 }
99 
100 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
101 {
102 	__be32 *p;
103 
104 	p = read_buf(xdr, 4);
105 	if (unlikely(p == NULL))
106 		return htonl(NFS4ERR_RESOURCE);
107 	fh->size = ntohl(*p);
108 	if (fh->size > NFS4_FHSIZE)
109 		return htonl(NFS4ERR_BADHANDLE);
110 	p = read_buf(xdr, fh->size);
111 	if (unlikely(p == NULL))
112 		return htonl(NFS4ERR_RESOURCE);
113 	memcpy(&fh->data[0], p, fh->size);
114 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
115 	return 0;
116 }
117 
118 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
119 {
120 	__be32 *p;
121 	unsigned int attrlen;
122 
123 	p = read_buf(xdr, 4);
124 	if (unlikely(p == NULL))
125 		return htonl(NFS4ERR_RESOURCE);
126 	attrlen = ntohl(*p);
127 	p = read_buf(xdr, attrlen << 2);
128 	if (unlikely(p == NULL))
129 		return htonl(NFS4ERR_RESOURCE);
130 	if (likely(attrlen > 0))
131 		bitmap[0] = ntohl(*p++);
132 	if (attrlen > 1)
133 		bitmap[1] = ntohl(*p);
134 	return 0;
135 }
136 
137 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
138 {
139 	__be32 *p;
140 
141 	p = read_buf(xdr, 16);
142 	if (unlikely(p == NULL))
143 		return htonl(NFS4ERR_RESOURCE);
144 	memcpy(stateid->data, p, 16);
145 	return 0;
146 }
147 
148 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
149 {
150 	__be32 *p;
151 	__be32 status;
152 
153 	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
154 	if (unlikely(status != 0))
155 		return status;
156 	/* We do not like overly long tags! */
157 	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
158 		printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
159 				__func__, hdr->taglen);
160 		return htonl(NFS4ERR_RESOURCE);
161 	}
162 	p = read_buf(xdr, 12);
163 	if (unlikely(p == NULL))
164 		return htonl(NFS4ERR_RESOURCE);
165 	hdr->minorversion = ntohl(*p++);
166 	/* Check minor version is zero or one. */
167 	if (hdr->minorversion <= 1) {
168 		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 */
169 	} else {
170 		printk(KERN_WARNING "%s: NFSv4 server callback with "
171 			"illegal minor version %u!\n",
172 			__func__, hdr->minorversion);
173 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
174 	}
175 	hdr->nops = ntohl(*p);
176 	dprintk("%s: minorversion %d nops %d\n", __func__,
177 		hdr->minorversion, hdr->nops);
178 	return 0;
179 }
180 
181 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
182 {
183 	__be32 *p;
184 	p = read_buf(xdr, 4);
185 	if (unlikely(p == NULL))
186 		return htonl(NFS4ERR_RESOURCE_HDR);
187 	*op = ntohl(*p);
188 	return 0;
189 }
190 
191 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
192 {
193 	__be32 status;
194 
195 	status = decode_fh(xdr, &args->fh);
196 	if (unlikely(status != 0))
197 		goto out;
198 	args->addr = svc_addr(rqstp);
199 	status = decode_bitmap(xdr, args->bitmap);
200 out:
201 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
202 	return status;
203 }
204 
205 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
206 {
207 	__be32 *p;
208 	__be32 status;
209 
210 	args->addr = svc_addr(rqstp);
211 	status = decode_stateid(xdr, &args->stateid);
212 	if (unlikely(status != 0))
213 		goto out;
214 	p = read_buf(xdr, 4);
215 	if (unlikely(p == NULL)) {
216 		status = htonl(NFS4ERR_RESOURCE);
217 		goto out;
218 	}
219 	args->truncate = ntohl(*p);
220 	status = decode_fh(xdr, &args->fh);
221 out:
222 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
223 	return status;
224 }
225 
226 #if defined(CONFIG_NFS_V4_1)
227 
228 static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
229 				       struct xdr_stream *xdr,
230 				       struct cb_layoutrecallargs *args)
231 {
232 	__be32 *p;
233 	__be32 status = 0;
234 	uint32_t iomode;
235 
236 	args->cbl_addr = svc_addr(rqstp);
237 	p = read_buf(xdr, 4 * sizeof(uint32_t));
238 	if (unlikely(p == NULL)) {
239 		status = htonl(NFS4ERR_BADXDR);
240 		goto out;
241 	}
242 
243 	args->cbl_layout_type = ntohl(*p++);
244 	/* Depite the spec's xdr, iomode really belongs in the FILE switch,
245 	 * as it is unusable and ignored with the other types.
246 	 */
247 	iomode = ntohl(*p++);
248 	args->cbl_layoutchanged = ntohl(*p++);
249 	args->cbl_recall_type = ntohl(*p++);
250 
251 	if (args->cbl_recall_type == RETURN_FILE) {
252 		args->cbl_range.iomode = iomode;
253 		status = decode_fh(xdr, &args->cbl_fh);
254 		if (unlikely(status != 0))
255 			goto out;
256 
257 		p = read_buf(xdr, 2 * sizeof(uint64_t));
258 		if (unlikely(p == NULL)) {
259 			status = htonl(NFS4ERR_BADXDR);
260 			goto out;
261 		}
262 		p = xdr_decode_hyper(p, &args->cbl_range.offset);
263 		p = xdr_decode_hyper(p, &args->cbl_range.length);
264 		status = decode_stateid(xdr, &args->cbl_stateid);
265 		if (unlikely(status != 0))
266 			goto out;
267 	} else if (args->cbl_recall_type == RETURN_FSID) {
268 		p = read_buf(xdr, 2 * sizeof(uint64_t));
269 		if (unlikely(p == NULL)) {
270 			status = htonl(NFS4ERR_BADXDR);
271 			goto out;
272 		}
273 		p = xdr_decode_hyper(p, &args->cbl_fsid.major);
274 		p = xdr_decode_hyper(p, &args->cbl_fsid.minor);
275 	} else if (args->cbl_recall_type != RETURN_ALL) {
276 		status = htonl(NFS4ERR_BADXDR);
277 		goto out;
278 	}
279 	dprintk("%s: ltype 0x%x iomode %d changed %d recall_type %d\n",
280 		__func__,
281 		args->cbl_layout_type, iomode,
282 		args->cbl_layoutchanged, args->cbl_recall_type);
283 out:
284 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
285 	return status;
286 }
287 
288 static
289 __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
290 				struct xdr_stream *xdr,
291 				struct cb_devicenotifyargs *args)
292 {
293 	__be32 *p;
294 	__be32 status = 0;
295 	u32 tmp;
296 	int n, i;
297 	args->ndevs = 0;
298 
299 	/* Num of device notifications */
300 	p = read_buf(xdr, sizeof(uint32_t));
301 	if (unlikely(p == NULL)) {
302 		status = htonl(NFS4ERR_BADXDR);
303 		goto out;
304 	}
305 	n = ntohl(*p++);
306 	if (n <= 0)
307 		goto out;
308 
309 	args->devs = kmalloc(n * sizeof(*args->devs), GFP_KERNEL);
310 	if (!args->devs) {
311 		status = htonl(NFS4ERR_DELAY);
312 		goto out;
313 	}
314 
315 	/* Decode each dev notification */
316 	for (i = 0; i < n; i++) {
317 		struct cb_devicenotifyitem *dev = &args->devs[i];
318 
319 		p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
320 		if (unlikely(p == NULL)) {
321 			status = htonl(NFS4ERR_BADXDR);
322 			goto err;
323 		}
324 
325 		tmp = ntohl(*p++);	/* bitmap size */
326 		if (tmp != 1) {
327 			status = htonl(NFS4ERR_INVAL);
328 			goto err;
329 		}
330 		dev->cbd_notify_type = ntohl(*p++);
331 		if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
332 		    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
333 			status = htonl(NFS4ERR_INVAL);
334 			goto err;
335 		}
336 
337 		tmp = ntohl(*p++);	/* opaque size */
338 		if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
339 		     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
340 		    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
341 		     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
342 			status = htonl(NFS4ERR_INVAL);
343 			goto err;
344 		}
345 		dev->cbd_layout_type = ntohl(*p++);
346 		memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
347 		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
348 
349 		if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
350 			p = read_buf(xdr, sizeof(uint32_t));
351 			if (unlikely(p == NULL)) {
352 				status = htonl(NFS4ERR_BADXDR);
353 				goto err;
354 			}
355 			dev->cbd_immediate = ntohl(*p++);
356 		} else {
357 			dev->cbd_immediate = 0;
358 		}
359 
360 		args->ndevs++;
361 
362 		dprintk("%s: type %d layout 0x%x immediate %d\n",
363 			__func__, dev->cbd_notify_type, dev->cbd_layout_type,
364 			dev->cbd_immediate);
365 	}
366 out:
367 	dprintk("%s: status %d ndevs %d\n",
368 		__func__, ntohl(status), args->ndevs);
369 	return status;
370 err:
371 	kfree(args->devs);
372 	goto out;
373 }
374 
375 static __be32 decode_sessionid(struct xdr_stream *xdr,
376 				 struct nfs4_sessionid *sid)
377 {
378 	__be32 *p;
379 	int len = NFS4_MAX_SESSIONID_LEN;
380 
381 	p = read_buf(xdr, len);
382 	if (unlikely(p == NULL))
383 		return htonl(NFS4ERR_RESOURCE);
384 
385 	memcpy(sid->data, p, len);
386 	return 0;
387 }
388 
389 static __be32 decode_rc_list(struct xdr_stream *xdr,
390 			       struct referring_call_list *rc_list)
391 {
392 	__be32 *p;
393 	int i;
394 	__be32 status;
395 
396 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
397 	if (status)
398 		goto out;
399 
400 	status = htonl(NFS4ERR_RESOURCE);
401 	p = read_buf(xdr, sizeof(uint32_t));
402 	if (unlikely(p == NULL))
403 		goto out;
404 
405 	rc_list->rcl_nrefcalls = ntohl(*p++);
406 	if (rc_list->rcl_nrefcalls) {
407 		p = read_buf(xdr,
408 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
409 		if (unlikely(p == NULL))
410 			goto out;
411 		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
412 						sizeof(*rc_list->rcl_refcalls),
413 						GFP_KERNEL);
414 		if (unlikely(rc_list->rcl_refcalls == NULL))
415 			goto out;
416 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
417 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
418 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
419 		}
420 	}
421 	status = 0;
422 
423 out:
424 	return status;
425 }
426 
427 static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
428 					struct xdr_stream *xdr,
429 					struct cb_sequenceargs *args)
430 {
431 	__be32 *p;
432 	int i;
433 	__be32 status;
434 
435 	status = decode_sessionid(xdr, &args->csa_sessionid);
436 	if (status)
437 		goto out;
438 
439 	status = htonl(NFS4ERR_RESOURCE);
440 	p = read_buf(xdr, 5 * sizeof(uint32_t));
441 	if (unlikely(p == NULL))
442 		goto out;
443 
444 	args->csa_addr = svc_addr(rqstp);
445 	args->csa_sequenceid = ntohl(*p++);
446 	args->csa_slotid = ntohl(*p++);
447 	args->csa_highestslotid = ntohl(*p++);
448 	args->csa_cachethis = ntohl(*p++);
449 	args->csa_nrclists = ntohl(*p++);
450 	args->csa_rclists = NULL;
451 	if (args->csa_nrclists) {
452 		args->csa_rclists = kmalloc(args->csa_nrclists *
453 					    sizeof(*args->csa_rclists),
454 					    GFP_KERNEL);
455 		if (unlikely(args->csa_rclists == NULL))
456 			goto out;
457 
458 		for (i = 0; i < args->csa_nrclists; i++) {
459 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
460 			if (status)
461 				goto out_free;
462 		}
463 	}
464 	status = 0;
465 
466 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
467 		"highestslotid %u cachethis %d nrclists %u\n",
468 		__func__,
469 		((u32 *)&args->csa_sessionid)[0],
470 		((u32 *)&args->csa_sessionid)[1],
471 		((u32 *)&args->csa_sessionid)[2],
472 		((u32 *)&args->csa_sessionid)[3],
473 		args->csa_sequenceid, args->csa_slotid,
474 		args->csa_highestslotid, args->csa_cachethis,
475 		args->csa_nrclists);
476 out:
477 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
478 	return status;
479 
480 out_free:
481 	for (i = 0; i < args->csa_nrclists; i++)
482 		kfree(args->csa_rclists[i].rcl_refcalls);
483 	kfree(args->csa_rclists);
484 	goto out;
485 }
486 
487 static __be32 decode_recallany_args(struct svc_rqst *rqstp,
488 				      struct xdr_stream *xdr,
489 				      struct cb_recallanyargs *args)
490 {
491 	uint32_t bitmap[2];
492 	__be32 *p, status;
493 
494 	args->craa_addr = svc_addr(rqstp);
495 	p = read_buf(xdr, 4);
496 	if (unlikely(p == NULL))
497 		return htonl(NFS4ERR_BADXDR);
498 	args->craa_objs_to_keep = ntohl(*p++);
499 	status = decode_bitmap(xdr, bitmap);
500 	if (unlikely(status))
501 		return status;
502 	args->craa_type_mask = bitmap[0];
503 
504 	return 0;
505 }
506 
507 static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
508 					struct xdr_stream *xdr,
509 					struct cb_recallslotargs *args)
510 {
511 	__be32 *p;
512 
513 	args->crsa_addr = svc_addr(rqstp);
514 	p = read_buf(xdr, 4);
515 	if (unlikely(p == NULL))
516 		return htonl(NFS4ERR_BADXDR);
517 	args->crsa_target_max_slots = ntohl(*p++);
518 	return 0;
519 }
520 
521 #endif /* CONFIG_NFS_V4_1 */
522 
523 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
524 {
525 	__be32 *p;
526 
527 	p = xdr_reserve_space(xdr, 4 + len);
528 	if (unlikely(p == NULL))
529 		return htonl(NFS4ERR_RESOURCE);
530 	xdr_encode_opaque(p, str, len);
531 	return 0;
532 }
533 
534 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
535 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
536 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
537 {
538 	__be32 bm[2];
539 	__be32 *p;
540 
541 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
542 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
543 	if (bm[1] != 0) {
544 		p = xdr_reserve_space(xdr, 16);
545 		if (unlikely(p == NULL))
546 			return htonl(NFS4ERR_RESOURCE);
547 		*p++ = htonl(2);
548 		*p++ = bm[0];
549 		*p++ = bm[1];
550 	} else if (bm[0] != 0) {
551 		p = xdr_reserve_space(xdr, 12);
552 		if (unlikely(p == NULL))
553 			return htonl(NFS4ERR_RESOURCE);
554 		*p++ = htonl(1);
555 		*p++ = bm[0];
556 	} else {
557 		p = xdr_reserve_space(xdr, 8);
558 		if (unlikely(p == NULL))
559 			return htonl(NFS4ERR_RESOURCE);
560 		*p++ = htonl(0);
561 	}
562 	*savep = p;
563 	return 0;
564 }
565 
566 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
567 {
568 	__be32 *p;
569 
570 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
571 		return 0;
572 	p = xdr_reserve_space(xdr, 8);
573 	if (unlikely(!p))
574 		return htonl(NFS4ERR_RESOURCE);
575 	p = xdr_encode_hyper(p, change);
576 	return 0;
577 }
578 
579 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
580 {
581 	__be32 *p;
582 
583 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
584 		return 0;
585 	p = xdr_reserve_space(xdr, 8);
586 	if (unlikely(!p))
587 		return htonl(NFS4ERR_RESOURCE);
588 	p = xdr_encode_hyper(p, size);
589 	return 0;
590 }
591 
592 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
593 {
594 	__be32 *p;
595 
596 	p = xdr_reserve_space(xdr, 12);
597 	if (unlikely(!p))
598 		return htonl(NFS4ERR_RESOURCE);
599 	p = xdr_encode_hyper(p, time->tv_sec);
600 	*p = htonl(time->tv_nsec);
601 	return 0;
602 }
603 
604 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
605 {
606 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
607 		return 0;
608 	return encode_attr_time(xdr,time);
609 }
610 
611 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
612 {
613 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
614 		return 0;
615 	return encode_attr_time(xdr,time);
616 }
617 
618 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
619 {
620 	__be32 status;
621 
622 	hdr->status = xdr_reserve_space(xdr, 4);
623 	if (unlikely(hdr->status == NULL))
624 		return htonl(NFS4ERR_RESOURCE);
625 	status = encode_string(xdr, hdr->taglen, hdr->tag);
626 	if (unlikely(status != 0))
627 		return status;
628 	hdr->nops = xdr_reserve_space(xdr, 4);
629 	if (unlikely(hdr->nops == NULL))
630 		return htonl(NFS4ERR_RESOURCE);
631 	return 0;
632 }
633 
634 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
635 {
636 	__be32 *p;
637 
638 	p = xdr_reserve_space(xdr, 8);
639 	if (unlikely(p == NULL))
640 		return htonl(NFS4ERR_RESOURCE_HDR);
641 	*p++ = htonl(op);
642 	*p = res;
643 	return 0;
644 }
645 
646 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
647 {
648 	__be32 *savep = NULL;
649 	__be32 status = res->status;
650 
651 	if (unlikely(status != 0))
652 		goto out;
653 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
654 	if (unlikely(status != 0))
655 		goto out;
656 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
657 	if (unlikely(status != 0))
658 		goto out;
659 	status = encode_attr_size(xdr, res->bitmap, res->size);
660 	if (unlikely(status != 0))
661 		goto out;
662 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
663 	if (unlikely(status != 0))
664 		goto out;
665 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
666 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
667 out:
668 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
669 	return status;
670 }
671 
672 #if defined(CONFIG_NFS_V4_1)
673 
674 static __be32 encode_sessionid(struct xdr_stream *xdr,
675 				 const struct nfs4_sessionid *sid)
676 {
677 	__be32 *p;
678 	int len = NFS4_MAX_SESSIONID_LEN;
679 
680 	p = xdr_reserve_space(xdr, len);
681 	if (unlikely(p == NULL))
682 		return htonl(NFS4ERR_RESOURCE);
683 
684 	memcpy(p, sid, len);
685 	return 0;
686 }
687 
688 static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
689 				       struct xdr_stream *xdr,
690 				       const struct cb_sequenceres *res)
691 {
692 	__be32 *p;
693 	unsigned status = res->csr_status;
694 
695 	if (unlikely(status != 0))
696 		goto out;
697 
698 	encode_sessionid(xdr, &res->csr_sessionid);
699 
700 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
701 	if (unlikely(p == NULL))
702 		return htonl(NFS4ERR_RESOURCE);
703 
704 	*p++ = htonl(res->csr_sequenceid);
705 	*p++ = htonl(res->csr_slotid);
706 	*p++ = htonl(res->csr_highestslotid);
707 	*p++ = htonl(res->csr_target_highestslotid);
708 out:
709 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
710 	return status;
711 }
712 
713 static __be32
714 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
715 {
716 	if (op_nr == OP_CB_SEQUENCE) {
717 		if (nop != 0)
718 			return htonl(NFS4ERR_SEQUENCE_POS);
719 	} else {
720 		if (nop == 0)
721 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
722 	}
723 
724 	switch (op_nr) {
725 	case OP_CB_GETATTR:
726 	case OP_CB_RECALL:
727 	case OP_CB_SEQUENCE:
728 	case OP_CB_RECALL_ANY:
729 	case OP_CB_RECALL_SLOT:
730 	case OP_CB_LAYOUTRECALL:
731 	case OP_CB_NOTIFY_DEVICEID:
732 		*op = &callback_ops[op_nr];
733 		break;
734 
735 	case OP_CB_NOTIFY:
736 	case OP_CB_PUSH_DELEG:
737 	case OP_CB_RECALLABLE_OBJ_AVAIL:
738 	case OP_CB_WANTS_CANCELLED:
739 	case OP_CB_NOTIFY_LOCK:
740 		return htonl(NFS4ERR_NOTSUPP);
741 
742 	default:
743 		return htonl(NFS4ERR_OP_ILLEGAL);
744 	}
745 
746 	return htonl(NFS_OK);
747 }
748 
749 static void nfs4_callback_free_slot(struct nfs4_session *session)
750 {
751 	struct nfs4_slot_table *tbl = &session->bc_slot_table;
752 
753 	spin_lock(&tbl->slot_tbl_lock);
754 	/*
755 	 * Let the state manager know callback processing done.
756 	 * A single slot, so highest used slotid is either 0 or -1
757 	 */
758 	tbl->highest_used_slotid = -1;
759 	nfs4_check_drain_bc_complete(session);
760 	spin_unlock(&tbl->slot_tbl_lock);
761 }
762 
763 static void nfs4_cb_free_slot(struct cb_process_state *cps)
764 {
765 	if (cps->slotid != -1)
766 		nfs4_callback_free_slot(cps->clp->cl_session);
767 }
768 
769 #else /* CONFIG_NFS_V4_1 */
770 
771 static __be32
772 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
773 {
774 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
775 }
776 
777 static void nfs4_cb_free_slot(struct cb_process_state *cps)
778 {
779 }
780 #endif /* CONFIG_NFS_V4_1 */
781 
782 static __be32
783 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
784 {
785 	switch (op_nr) {
786 	case OP_CB_GETATTR:
787 	case OP_CB_RECALL:
788 		*op = &callback_ops[op_nr];
789 		break;
790 	default:
791 		return htonl(NFS4ERR_OP_ILLEGAL);
792 	}
793 
794 	return htonl(NFS_OK);
795 }
796 
797 static __be32 process_op(uint32_t minorversion, int nop,
798 		struct svc_rqst *rqstp,
799 		struct xdr_stream *xdr_in, void *argp,
800 		struct xdr_stream *xdr_out, void *resp,
801 		struct cb_process_state *cps)
802 {
803 	struct callback_op *op = &callback_ops[0];
804 	unsigned int op_nr;
805 	__be32 status;
806 	long maxlen;
807 	__be32 res;
808 
809 	dprintk("%s: start\n", __func__);
810 	status = decode_op_hdr(xdr_in, &op_nr);
811 	if (unlikely(status))
812 		return status;
813 
814 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
815 		__func__, minorversion, nop, op_nr);
816 
817 	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
818 				preprocess_nfs4_op(op_nr, &op);
819 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
820 		op_nr = OP_CB_ILLEGAL;
821 	if (status)
822 		goto encode_hdr;
823 
824 	if (cps->drc_status) {
825 		status = cps->drc_status;
826 		goto encode_hdr;
827 	}
828 
829 	maxlen = xdr_out->end - xdr_out->p;
830 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
831 		status = op->decode_args(rqstp, xdr_in, argp);
832 		if (likely(status == 0))
833 			status = op->process_op(argp, resp, cps);
834 	} else
835 		status = htonl(NFS4ERR_RESOURCE);
836 
837 encode_hdr:
838 	res = encode_op_hdr(xdr_out, op_nr, status);
839 	if (unlikely(res))
840 		return res;
841 	if (op->encode_res != NULL && status == 0)
842 		status = op->encode_res(rqstp, xdr_out, resp);
843 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
844 	return status;
845 }
846 
847 /*
848  * Decode, process and encode a COMPOUND
849  */
850 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
851 {
852 	struct cb_compound_hdr_arg hdr_arg = { 0 };
853 	struct cb_compound_hdr_res hdr_res = { NULL };
854 	struct xdr_stream xdr_in, xdr_out;
855 	__be32 *p, status;
856 	struct cb_process_state cps = {
857 		.drc_status = 0,
858 		.clp = NULL,
859 		.slotid = -1,
860 	};
861 	unsigned int nops = 0;
862 
863 	dprintk("%s: start\n", __func__);
864 
865 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
866 
867 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
868 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
869 
870 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
871 	if (status == __constant_htonl(NFS4ERR_RESOURCE))
872 		return rpc_garbage_args;
873 
874 	if (hdr_arg.minorversion == 0) {
875 		cps.clp = nfs4_find_client_ident(hdr_arg.cb_ident);
876 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
877 			return rpc_drop_reply;
878 	}
879 
880 	hdr_res.taglen = hdr_arg.taglen;
881 	hdr_res.tag = hdr_arg.tag;
882 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
883 		return rpc_system_err;
884 
885 	while (status == 0 && nops != hdr_arg.nops) {
886 		status = process_op(hdr_arg.minorversion, nops, rqstp,
887 				    &xdr_in, argp, &xdr_out, resp, &cps);
888 		nops++;
889 	}
890 
891 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
892 	* resource error in cb_compound status without returning op */
893 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
894 		status = htonl(NFS4ERR_RESOURCE);
895 		nops--;
896 	}
897 
898 	*hdr_res.status = status;
899 	*hdr_res.nops = htonl(nops);
900 	nfs4_cb_free_slot(&cps);
901 	nfs_put_client(cps.clp);
902 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
903 	return rpc_success;
904 }
905 
906 /*
907  * Define NFS4 callback COMPOUND ops.
908  */
909 static struct callback_op callback_ops[] = {
910 	[0] = {
911 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
912 	},
913 	[OP_CB_GETATTR] = {
914 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
915 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
916 		.encode_res = (callback_encode_res_t)encode_getattr_res,
917 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
918 	},
919 	[OP_CB_RECALL] = {
920 		.process_op = (callback_process_op_t)nfs4_callback_recall,
921 		.decode_args = (callback_decode_arg_t)decode_recall_args,
922 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
923 	},
924 #if defined(CONFIG_NFS_V4_1)
925 	[OP_CB_LAYOUTRECALL] = {
926 		.process_op = (callback_process_op_t)nfs4_callback_layoutrecall,
927 		.decode_args =
928 			(callback_decode_arg_t)decode_layoutrecall_args,
929 		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
930 	},
931 	[OP_CB_NOTIFY_DEVICEID] = {
932 		.process_op = (callback_process_op_t)nfs4_callback_devicenotify,
933 		.decode_args =
934 			(callback_decode_arg_t)decode_devicenotify_args,
935 		.res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
936 	},
937 	[OP_CB_SEQUENCE] = {
938 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
939 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
940 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
941 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
942 	},
943 	[OP_CB_RECALL_ANY] = {
944 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
945 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
946 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
947 	},
948 	[OP_CB_RECALL_SLOT] = {
949 		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
950 		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
951 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
952 	},
953 #endif /* CONFIG_NFS_V4_1 */
954 };
955 
956 /*
957  * Define NFS4 callback procedures
958  */
959 static struct svc_procedure nfs4_callback_procedures1[] = {
960 	[CB_NULL] = {
961 		.pc_func = nfs4_callback_null,
962 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
963 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
964 		.pc_xdrressize = 1,
965 	},
966 	[CB_COMPOUND] = {
967 		.pc_func = nfs4_callback_compound,
968 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
969 		.pc_argsize = 256,
970 		.pc_ressize = 256,
971 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
972 	}
973 };
974 
975 struct svc_version nfs4_callback_version1 = {
976 	.vs_vers = 1,
977 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
978 	.vs_proc = nfs4_callback_procedures1,
979 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
980 	.vs_dispatch = NULL,
981 	.vs_hidden = 1,
982 };
983 
984 struct svc_version nfs4_callback_version4 = {
985 	.vs_vers = 4,
986 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
987 	.vs_proc = nfs4_callback_procedures1,
988 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
989 	.vs_dispatch = NULL,
990 	.vs_hidden = 1,
991 };
992