Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
/*
 * linux/fs/nfs/callback_xdr.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback encode/decode procedures
 */
#include <linux/kernel.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/bc_xprt.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "internal.h"

#define CB_OP_TAGLEN_MAXSZ	(512)
#define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
#define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
#define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
				CB_OP_GETATTR_BITMAP_MAXSZ + \
				2 + 2 + 3 + 3)
#define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)

#if defined(CONFIG_NFS_V4_1)
#define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
					4 + 1 + 3)
#define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#endif /* CONFIG_NFS_V4_1 */

#define NFSDBG_FACILITY NFSDBG_CALLBACK

/* Internal error code */
#define NFS4ERR_RESOURCE_HDR	11050

typedef __be32 (*callback_process_op_t)(void *, void *,
					struct cb_process_state *);
typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);


struct callback_op {
	callback_process_op_t process_op;
	callback_decode_arg_t decode_args;
	callback_encode_res_t encode_res;
	long res_maxsize;
};

static struct callback_op callback_ops[];

static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
	return htonl(NFS4_OK);
}

static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
	return xdr_argsize_check(rqstp, p);
}

static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
{
	return xdr_ressize_check(rqstp, p);
}

static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
{
	__be32 *p;

	p = xdr_inline_decode(xdr, nbytes);
	if (unlikely(p == NULL))
		printk(KERN_WARNING "NFS: NFSv4 callback reply buffer overflowed!\n");
	return p;
}

static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
{
	__be32 *p;

	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	*len = ntohl(*p);

	if (*len != 0) {
		p = read_buf(xdr, *len);
		if (unlikely(p == NULL))
			return htonl(NFS4ERR_RESOURCE);
		*str = (const char *)p;
	} else
		*str = NULL;

	return 0;
}

static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
{
	__be32 *p;

	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	fh->size = ntohl(*p);
	if (fh->size > NFS4_FHSIZE)
		return htonl(NFS4ERR_BADHANDLE);
	p = read_buf(xdr, fh->size);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	memcpy(&fh->data[0], p, fh->size);
	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
	return 0;
}

static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
{
	__be32 *p;
	unsigned int attrlen;

	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	attrlen = ntohl(*p);
	p = read_buf(xdr, attrlen << 2);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	if (likely(attrlen > 0))
		bitmap[0] = ntohl(*p++);
	if (attrlen > 1)
		bitmap[1] = ntohl(*p);
	return 0;
}

static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
{
	__be32 *p;

	p = read_buf(xdr, NFS4_STATEID_SIZE);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	memcpy(stateid, p, NFS4_STATEID_SIZE);
	return 0;
}

static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
{
	__be32 *p;
	__be32 status;

	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
	if (unlikely(status != 0))
		return status;
	/* We do not like overly long tags! */
	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
		printk("NFS: NFSv4 CALLBACK %s: client sent tag of length %u\n",
				__func__, hdr->taglen);
		return htonl(NFS4ERR_RESOURCE);
	}
	p = read_buf(xdr, 12);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	hdr->minorversion = ntohl(*p++);
	/* Check minor version is zero or one. */
	if (hdr->minorversion <= 1) {
		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 */
	} else {
		pr_warn_ratelimited("NFS: %s: NFSv4 server callback with "
			"illegal minor version %u!\n",
			__func__, hdr->minorversion);
		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
	}
	hdr->nops = ntohl(*p);
	dprintk("%s: minorversion %d nops %d\n", __func__,
		hdr->minorversion, hdr->nops);
	return 0;
}

static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
{
	__be32 *p;
	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE_HDR);
	*op = ntohl(*p);
	return 0;
}

static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
{
	__be32 status;

	status = decode_fh(xdr, &args->fh);
	if (unlikely(status != 0))
		goto out;
	args->addr = svc_addr(rqstp);
	status = decode_bitmap(xdr, args->bitmap);
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
}

static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
{
	__be32 *p;
	__be32 status;

	args->addr = svc_addr(rqstp);
	status = decode_stateid(xdr, &args->stateid);
	if (unlikely(status != 0))
		goto out;
	p = read_buf(xdr, 4);
	if (unlikely(p == NULL)) {
		status = htonl(NFS4ERR_RESOURCE);
		goto out;
	}
	args->truncate = ntohl(*p);
	status = decode_fh(xdr, &args->fh);
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
}

#if defined(CONFIG_NFS_V4_1)

static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
				       struct xdr_stream *xdr,
				       struct cb_layoutrecallargs *args)
{
	__be32 *p;
	__be32 status = 0;
	uint32_t iomode;

	args->cbl_addr = svc_addr(rqstp);
	p = read_buf(xdr, 4 * sizeof(uint32_t));
	if (unlikely(p == NULL)) {
		status = htonl(NFS4ERR_BADXDR);
		goto out;
	}

	args->cbl_layout_type = ntohl(*p++);
	/* Depite the spec's xdr, iomode really belongs in the FILE switch,
	 * as it is unusable and ignored with the other types.
	 */
	iomode = ntohl(*p++);
	args->cbl_layoutchanged = ntohl(*p++);
	args->cbl_recall_type = ntohl(*p++);

	if (args->cbl_recall_type == RETURN_FILE) {
		args->cbl_range.iomode = iomode;
		status = decode_fh(xdr, &args->cbl_fh);
		if (unlikely(status != 0))
			goto out;

		p = read_buf(xdr, 2 * sizeof(uint64_t));
		if (unlikely(p == NULL)) {
			status = htonl(NFS4ERR_BADXDR);
			goto out;
		}
		p = xdr_decode_hyper(p, &args->cbl_range.offset);
		p = xdr_decode_hyper(p, &args->cbl_range.length);
		status = decode_stateid(xdr, &args->cbl_stateid);
		if (unlikely(status != 0))
			goto out;
	} else if (args->cbl_recall_type == RETURN_FSID) {
		p = read_buf(xdr, 2 * sizeof(uint64_t));
		if (unlikely(p == NULL)) {
			status = htonl(NFS4ERR_BADXDR);
			goto out;
		}
		p = xdr_decode_hyper(p, &args->cbl_fsid.major);
		p = xdr_decode_hyper(p, &args->cbl_fsid.minor);
	} else if (args->cbl_recall_type != RETURN_ALL) {
		status = htonl(NFS4ERR_BADXDR);
		goto out;
	}
	dprintk("%s: ltype 0x%x iomode %d changed %d recall_type %d\n",
		__func__,
		args->cbl_layout_type, iomode,
		args->cbl_layoutchanged, args->cbl_recall_type);
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
}

static
__be32 decode_devicenotify_args(struct svc_rqst *rqstp,
				struct xdr_stream *xdr,
				struct cb_devicenotifyargs *args)
{
	__be32 *p;
	__be32 status = 0;
	u32 tmp;
	int n, i;
	args->ndevs = 0;

	/* Num of device notifications */
	p = read_buf(xdr, sizeof(uint32_t));
	if (unlikely(p == NULL)) {
		status = htonl(NFS4ERR_BADXDR);
		goto out;
	}
	n = ntohl(*p++);
	if (n <= 0)
		goto out;
	if (n > ULONG_MAX / sizeof(*args->devs)) {
		status = htonl(NFS4ERR_BADXDR);
		goto out;
	}

	args->devs = kmalloc(n * sizeof(*args->devs), GFP_KERNEL);
	if (!args->devs) {
		status = htonl(NFS4ERR_DELAY);
		goto out;
	}

	/* Decode each dev notification */
	for (i = 0; i < n; i++) {
		struct cb_devicenotifyitem *dev = &args->devs[i];

		p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
		if (unlikely(p == NULL)) {
			status = htonl(NFS4ERR_BADXDR);
			goto err;
		}

		tmp = ntohl(*p++);	/* bitmap size */
		if (tmp != 1) {
			status = htonl(NFS4ERR_INVAL);
			goto err;
		}
		dev->cbd_notify_type = ntohl(*p++);
		if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
		    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
			status = htonl(NFS4ERR_INVAL);
			goto err;
		}

		tmp = ntohl(*p++);	/* opaque size */
		if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
		     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
		    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
		     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
			status = htonl(NFS4ERR_INVAL);
			goto err;
		}
		dev->cbd_layout_type = ntohl(*p++);
		memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);

		if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
			p = read_buf(xdr, sizeof(uint32_t));
			if (unlikely(p == NULL)) {
				status = htonl(NFS4ERR_BADXDR);
				goto err;
			}
			dev->cbd_immediate = ntohl(*p++);
		} else {
			dev->cbd_immediate = 0;
		}

		args->ndevs++;

		dprintk("%s: type %d layout 0x%x immediate %d\n",
			__func__, dev->cbd_notify_type, dev->cbd_layout_type,
			dev->cbd_immediate);
	}
out:
	dprintk("%s: status %d ndevs %d\n",
		__func__, ntohl(status), args->ndevs);
	return status;
err:
	kfree(args->devs);
	goto out;
}

static __be32 decode_sessionid(struct xdr_stream *xdr,
				 struct nfs4_sessionid *sid)
{
	__be32 *p;
	int len = NFS4_MAX_SESSIONID_LEN;

	p = read_buf(xdr, len);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);

	memcpy(sid->data, p, len);
	return 0;
}

static __be32 decode_rc_list(struct xdr_stream *xdr,
			       struct referring_call_list *rc_list)
{
	__be32 *p;
	int i;
	__be32 status;

	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
	if (status)
		goto out;

	status = htonl(NFS4ERR_RESOURCE);
	p = read_buf(xdr, sizeof(uint32_t));
	if (unlikely(p == NULL))
		goto out;

	rc_list->rcl_nrefcalls = ntohl(*p++);
	if (rc_list->rcl_nrefcalls) {
		p = read_buf(xdr,
			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
		if (unlikely(p == NULL))
			goto out;
		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
						sizeof(*rc_list->rcl_refcalls),
						GFP_KERNEL);
		if (unlikely(rc_list->rcl_refcalls == NULL))
			goto out;
		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
		}
	}
	status = 0;

out:
	return status;
}

static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
					struct xdr_stream *xdr,
					struct cb_sequenceargs *args)
{
	__be32 *p;
	int i;
	__be32 status;

	status = decode_sessionid(xdr, &args->csa_sessionid);
	if (status)
		goto out;

	status = htonl(NFS4ERR_RESOURCE);
	p = read_buf(xdr, 5 * sizeof(uint32_t));
	if (unlikely(p == NULL))
		goto out;

	args->csa_addr = svc_addr(rqstp);
	args->csa_sequenceid = ntohl(*p++);
	args->csa_slotid = ntohl(*p++);
	args->csa_highestslotid = ntohl(*p++);
	args->csa_cachethis = ntohl(*p++);
	args->csa_nrclists = ntohl(*p++);
	args->csa_rclists = NULL;
	if (args->csa_nrclists) {
		args->csa_rclists = kmalloc_array(args->csa_nrclists,
						  sizeof(*args->csa_rclists),
						  GFP_KERNEL);
		if (unlikely(args->csa_rclists == NULL))
			goto out;

		for (i = 0; i < args->csa_nrclists; i++) {
			status = decode_rc_list(xdr, &args->csa_rclists[i]);
			if (status)
				goto out_free;
		}
	}
	status = 0;

	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
		"highestslotid %u cachethis %d nrclists %u\n",
		__func__,
		((u32 *)&args->csa_sessionid)[0],
		((u32 *)&args->csa_sessionid)[1],
		((u32 *)&args->csa_sessionid)[2],
		((u32 *)&args->csa_sessionid)[3],
		args->csa_sequenceid, args->csa_slotid,
		args->csa_highestslotid, args->csa_cachethis,
		args->csa_nrclists);
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;

out_free:
	for (i = 0; i < args->csa_nrclists; i++)
		kfree(args->csa_rclists[i].rcl_refcalls);
	kfree(args->csa_rclists);
	goto out;
}

static __be32 decode_recallany_args(struct svc_rqst *rqstp,
				      struct xdr_stream *xdr,
				      struct cb_recallanyargs *args)
{
	uint32_t bitmap[2];
	__be32 *p, status;

	args->craa_addr = svc_addr(rqstp);
	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_BADXDR);
	args->craa_objs_to_keep = ntohl(*p++);
	status = decode_bitmap(xdr, bitmap);
	if (unlikely(status))
		return status;
	args->craa_type_mask = bitmap[0];

	return 0;
}

static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
					struct xdr_stream *xdr,
					struct cb_recallslotargs *args)
{
	__be32 *p;

	args->crsa_addr = svc_addr(rqstp);
	p = read_buf(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_BADXDR);
	args->crsa_target_max_slots = ntohl(*p++);
	return 0;
}

#endif /* CONFIG_NFS_V4_1 */

static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
{
	__be32 *p;

	p = xdr_reserve_space(xdr, 4 + len);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	xdr_encode_opaque(p, str, len);
	return 0;
}

#define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
#define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
{
	__be32 bm[2];
	__be32 *p;

	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
	if (bm[1] != 0) {
		p = xdr_reserve_space(xdr, 16);
		if (unlikely(p == NULL))
			return htonl(NFS4ERR_RESOURCE);
		*p++ = htonl(2);
		*p++ = bm[0];
		*p++ = bm[1];
	} else if (bm[0] != 0) {
		p = xdr_reserve_space(xdr, 12);
		if (unlikely(p == NULL))
			return htonl(NFS4ERR_RESOURCE);
		*p++ = htonl(1);
		*p++ = bm[0];
	} else {
		p = xdr_reserve_space(xdr, 8);
		if (unlikely(p == NULL))
			return htonl(NFS4ERR_RESOURCE);
		*p++ = htonl(0);
	}
	*savep = p;
	return 0;
}

static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
{
	__be32 *p;

	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
		return 0;
	p = xdr_reserve_space(xdr, 8);
	if (unlikely(!p))
		return htonl(NFS4ERR_RESOURCE);
	p = xdr_encode_hyper(p, change);
	return 0;
}

static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
{
	__be32 *p;

	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
		return 0;
	p = xdr_reserve_space(xdr, 8);
	if (unlikely(!p))
		return htonl(NFS4ERR_RESOURCE);
	p = xdr_encode_hyper(p, size);
	return 0;
}

static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
{
	__be32 *p;

	p = xdr_reserve_space(xdr, 12);
	if (unlikely(!p))
		return htonl(NFS4ERR_RESOURCE);
	p = xdr_encode_hyper(p, time->tv_sec);
	*p = htonl(time->tv_nsec);
	return 0;
}

static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
{
	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
		return 0;
	return encode_attr_time(xdr,time);
}

static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
{
	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
		return 0;
	return encode_attr_time(xdr,time);
}

static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
{
	__be32 status;

	hdr->status = xdr_reserve_space(xdr, 4);
	if (unlikely(hdr->status == NULL))
		return htonl(NFS4ERR_RESOURCE);
	status = encode_string(xdr, hdr->taglen, hdr->tag);
	if (unlikely(status != 0))
		return status;
	hdr->nops = xdr_reserve_space(xdr, 4);
	if (unlikely(hdr->nops == NULL))
		return htonl(NFS4ERR_RESOURCE);
	return 0;
}

static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
{
	__be32 *p;
	
	p = xdr_reserve_space(xdr, 8);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE_HDR);
	*p++ = htonl(op);
	*p = res;
	return 0;
}

static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
{
	__be32 *savep = NULL;
	__be32 status = res->status;
	
	if (unlikely(status != 0))
		goto out;
	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
	if (unlikely(status != 0))
		goto out;
	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
	if (unlikely(status != 0))
		goto out;
	status = encode_attr_size(xdr, res->bitmap, res->size);
	if (unlikely(status != 0))
		goto out;
	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
	if (unlikely(status != 0))
		goto out;
	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
}

#if defined(CONFIG_NFS_V4_1)

static __be32 encode_sessionid(struct xdr_stream *xdr,
				 const struct nfs4_sessionid *sid)
{
	__be32 *p;
	int len = NFS4_MAX_SESSIONID_LEN;

	p = xdr_reserve_space(xdr, len);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);

	memcpy(p, sid, len);
	return 0;
}

static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
				       struct xdr_stream *xdr,
				       const struct cb_sequenceres *res)
{
	__be32 *p;
	__be32 status = res->csr_status;

	if (unlikely(status != 0))
		goto out;

	encode_sessionid(xdr, &res->csr_sessionid);

	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);

	*p++ = htonl(res->csr_sequenceid);
	*p++ = htonl(res->csr_slotid);
	*p++ = htonl(res->csr_highestslotid);
	*p++ = htonl(res->csr_target_highestslotid);
out:
	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
	return status;
}

static __be32
preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
{
	if (op_nr == OP_CB_SEQUENCE) {
		if (nop != 0)
			return htonl(NFS4ERR_SEQUENCE_POS);
	} else {
		if (nop == 0)
			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
	}

	switch (op_nr) {
	case OP_CB_GETATTR:
	case OP_CB_RECALL:
	case OP_CB_SEQUENCE:
	case OP_CB_RECALL_ANY:
	case OP_CB_RECALL_SLOT:
	case OP_CB_LAYOUTRECALL:
	case OP_CB_NOTIFY_DEVICEID:
		*op = &callback_ops[op_nr];
		break;

	case OP_CB_NOTIFY:
	case OP_CB_PUSH_DELEG:
	case OP_CB_RECALLABLE_OBJ_AVAIL:
	case OP_CB_WANTS_CANCELLED:
	case OP_CB_NOTIFY_LOCK:
		return htonl(NFS4ERR_NOTSUPP);

	default:
		return htonl(NFS4ERR_OP_ILLEGAL);
	}

	return htonl(NFS_OK);
}

static void nfs4_callback_free_slot(struct nfs4_session *session)
{
	struct nfs4_slot_table *tbl = &session->bc_slot_table;

	spin_lock(&tbl->slot_tbl_lock);
	/*
	 * Let the state manager know callback processing done.
	 * A single slot, so highest used slotid is either 0 or -1
	 */
	tbl->highest_used_slotid = NFS4_NO_SLOT;
	nfs4_check_drain_bc_complete(session);
	spin_unlock(&tbl->slot_tbl_lock);
}

static void nfs4_cb_free_slot(struct cb_process_state *cps)
{
	if (cps->slotid != NFS4_NO_SLOT)
		nfs4_callback_free_slot(cps->clp->cl_session);
}

#else /* CONFIG_NFS_V4_1 */

static __be32
preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
{
	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
}

static void nfs4_cb_free_slot(struct cb_process_state *cps)
{
}
#endif /* CONFIG_NFS_V4_1 */

static __be32
preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
{
	switch (op_nr) {
	case OP_CB_GETATTR:
	case OP_CB_RECALL:
		*op = &callback_ops[op_nr];
		break;
	default:
		return htonl(NFS4ERR_OP_ILLEGAL);
	}

	return htonl(NFS_OK);
}

static __be32 process_op(uint32_t minorversion, int nop,
		struct svc_rqst *rqstp,
		struct xdr_stream *xdr_in, void *argp,
		struct xdr_stream *xdr_out, void *resp,
		struct cb_process_state *cps)
{
	struct callback_op *op = &callback_ops[0];
	unsigned int op_nr;
	__be32 status;
	long maxlen;
	__be32 res;

	dprintk("%s: start\n", __func__);
	status = decode_op_hdr(xdr_in, &op_nr);
	if (unlikely(status))
		return status;

	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
		__func__, minorversion, nop, op_nr);

	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
				preprocess_nfs4_op(op_nr, &op);
	if (status == htonl(NFS4ERR_OP_ILLEGAL))
		op_nr = OP_CB_ILLEGAL;
	if (status)
		goto encode_hdr;

	if (cps->drc_status) {
		status = cps->drc_status;
		goto encode_hdr;
	}

	maxlen = xdr_out->end - xdr_out->p;
	if (maxlen > 0 && maxlen < PAGE_SIZE) {
		status = op->decode_args(rqstp, xdr_in, argp);
		if (likely(status == 0))
			status = op->process_op(argp, resp, cps);
	} else
		status = htonl(NFS4ERR_RESOURCE);

encode_hdr:
	res = encode_op_hdr(xdr_out, op_nr, status);
	if (unlikely(res))
		return res;
	if (op->encode_res != NULL && status == 0)
		status = op->encode_res(rqstp, xdr_out, resp);
	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
	return status;
}

/*
 * Decode, process and encode a COMPOUND
 */
static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
{
	struct cb_compound_hdr_arg hdr_arg = { 0 };
	struct cb_compound_hdr_res hdr_res = { NULL };
	struct xdr_stream xdr_in, xdr_out;
	__be32 *p, status;
	struct cb_process_state cps = {
		.drc_status = 0,
		.clp = NULL,
		.slotid = NFS4_NO_SLOT,
		.net = SVC_NET(rqstp),
	};
	unsigned int nops = 0;

	dprintk("%s: start\n", __func__);

	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);

	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);

	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
	if (status == __constant_htonl(NFS4ERR_RESOURCE))
		return rpc_garbage_args;

	if (hdr_arg.minorversion == 0) {
		cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
			return rpc_drop_reply;
	}

	hdr_res.taglen = hdr_arg.taglen;
	hdr_res.tag = hdr_arg.tag;
	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
		return rpc_system_err;

	while (status == 0 && nops != hdr_arg.nops) {
		status = process_op(hdr_arg.minorversion, nops, rqstp,
				    &xdr_in, argp, &xdr_out, resp, &cps);
		nops++;
	}

	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
	* resource error in cb_compound status without returning op */
	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
		status = htonl(NFS4ERR_RESOURCE);
		nops--;
	}

	*hdr_res.status = status;
	*hdr_res.nops = htonl(nops);
	nfs4_cb_free_slot(&cps);
	nfs_put_client(cps.clp);
	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
	return rpc_success;
}

/*
 * Define NFS4 callback COMPOUND ops.
 */
static struct callback_op callback_ops[] = {
	[0] = {
		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
	},
	[OP_CB_GETATTR] = {
		.process_op = (callback_process_op_t)nfs4_callback_getattr,
		.decode_args = (callback_decode_arg_t)decode_getattr_args,
		.encode_res = (callback_encode_res_t)encode_getattr_res,
		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
	},
	[OP_CB_RECALL] = {
		.process_op = (callback_process_op_t)nfs4_callback_recall,
		.decode_args = (callback_decode_arg_t)decode_recall_args,
		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
	},
#if defined(CONFIG_NFS_V4_1)
	[OP_CB_LAYOUTRECALL] = {
		.process_op = (callback_process_op_t)nfs4_callback_layoutrecall,
		.decode_args =
			(callback_decode_arg_t)decode_layoutrecall_args,
		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
	},
	[OP_CB_NOTIFY_DEVICEID] = {
		.process_op = (callback_process_op_t)nfs4_callback_devicenotify,
		.decode_args =
			(callback_decode_arg_t)decode_devicenotify_args,
		.res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
	},
	[OP_CB_SEQUENCE] = {
		.process_op = (callback_process_op_t)nfs4_callback_sequence,
		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
	},
	[OP_CB_RECALL_ANY] = {
		.process_op = (callback_process_op_t)nfs4_callback_recallany,
		.decode_args = (callback_decode_arg_t)decode_recallany_args,
		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
	},
	[OP_CB_RECALL_SLOT] = {
		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
	},
#endif /* CONFIG_NFS_V4_1 */
};

/*
 * Define NFS4 callback procedures
 */
static struct svc_procedure nfs4_callback_procedures1[] = {
	[CB_NULL] = {
		.pc_func = nfs4_callback_null,
		.pc_decode = (kxdrproc_t)nfs4_decode_void,
		.pc_encode = (kxdrproc_t)nfs4_encode_void,
		.pc_xdrressize = 1,
	},
	[CB_COMPOUND] = {
		.pc_func = nfs4_callback_compound,
		.pc_encode = (kxdrproc_t)nfs4_encode_void,
		.pc_argsize = 256,
		.pc_ressize = 256,
		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
	}
};

struct svc_version nfs4_callback_version1 = {
	.vs_vers = 1,
	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
	.vs_proc = nfs4_callback_procedures1,
	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
	.vs_dispatch = NULL,
	.vs_hidden = 1,
};

struct svc_version nfs4_callback_version4 = {
	.vs_vers = 4,
	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
	.vs_proc = nfs4_callback_procedures1,
	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
	.vs_dispatch = NULL,
	.vs_hidden = 1,
};