aboutsummaryrefslogtreecommitdiff
path: root/fs/nfs/nfs4filelayout.c
blob: 0bafcc91c27f8d8513dc1a7c8776fefd3411eee2 (plain)
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
/*
 *  Module for the pnfs nfs4 file layout driver.
 *  Defines all I/O and Policy interface operations, plus code
 *  to register itself with the pNFS client.
 *
 *  Copyright (c) 2002
 *  The Regents of the University of Michigan
 *  All Rights Reserved
 *
 *  Dean Hildebrand <dhildebz@umich.edu>
 *
 *  Permission is granted to use, copy, create derivative works, and
 *  redistribute this software and such derivative works for any purpose,
 *  so long as the name of the University of Michigan is not used in
 *  any advertising or publicity pertaining to the use or distribution
 *  of this software without specific, written prior authorization. If
 *  the above copyright notice or any other identification of the
 *  University of Michigan is included in any copy of any portion of
 *  this software, then the disclaimer below must also be included.
 *
 *  This software is provided as is, without representation or warranty
 *  of any kind either express or implied, including without limitation
 *  the implied warranties of merchantability, fitness for a particular
 *  purpose, or noninfringement.  The Regents of the University of
 *  Michigan shall not be liable for any damages, including special,
 *  indirect, incidental, or consequential damages, with respect to any
 *  claim arising out of or in connection with the use of the software,
 *  even if it has been or is hereafter advised of the possibility of
 *  such damages.
 */

#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>

#include "internal.h"
#include "nfs4filelayout.h"

#define NFSDBG_FACILITY         NFSDBG_PNFS_LD

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dean Hildebrand <dhildebz@umich.edu>");
MODULE_DESCRIPTION("The NFSv4 file layout driver");

#define FILELAYOUT_POLL_RETRY_MAX     (15*HZ)

static loff_t
filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
			    loff_t offset)
{
	u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
	u64 tmp;

	offset -= flseg->pattern_offset;
	tmp = offset;
	do_div(tmp, stripe_width);

	return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
}

/* This function is used by the layout driver to calculate the
 * offset of the file on the dserver based on whether the
 * layout type is STRIPE_DENSE or STRIPE_SPARSE
 */
static loff_t
filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset)
{
	struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);

	switch (flseg->stripe_type) {
	case STRIPE_SPARSE:
		return offset;

	case STRIPE_DENSE:
		return filelayout_get_dense_offset(flseg, offset);
	}

	BUG();
}

/* For data server errors we don't recover from */
static void
filelayout_set_lo_fail(struct pnfs_layout_segment *lseg)
{
	if (lseg->pls_range.iomode == IOMODE_RW) {
		dprintk("%s Setting layout IOMODE_RW fail bit\n", __func__);
		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
	} else {
		dprintk("%s Setting layout IOMODE_READ fail bit\n", __func__);
		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
	}
}

static int filelayout_async_handle_error(struct rpc_task *task,
					 struct nfs4_state *state,
					 struct nfs_client *clp,
					 int *reset)
{
	if (task->tk_status >= 0)
		return 0;

	*reset = 0;

	switch (task->tk_status) {
	case -NFS4ERR_BADSESSION:
	case -NFS4ERR_BADSLOT:
	case -NFS4ERR_BAD_HIGH_SLOT:
	case -NFS4ERR_DEADSESSION:
	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
	case -NFS4ERR_SEQ_FALSE_RETRY:
	case -NFS4ERR_SEQ_MISORDERED:
		dprintk("%s ERROR %d, Reset session. Exchangeid "
			"flags 0x%x\n", __func__, task->tk_status,
			clp->cl_exchange_flags);
		nfs4_schedule_session_recovery(clp->cl_session);
		break;
	case -NFS4ERR_DELAY:
	case -NFS4ERR_GRACE:
	case -EKEYEXPIRED:
		rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
		break;
	case -NFS4ERR_RETRY_UNCACHED_REP:
		break;
	default:
		dprintk("%s DS error. Retry through MDS %d\n", __func__,
			task->tk_status);
		*reset = 1;
		break;
	}
	task->tk_status = 0;
	return -EAGAIN;
}

/* NFS_PROTO call done callback routines */

static int filelayout_read_done_cb(struct rpc_task *task,
				struct nfs_read_data *data)
{
	struct nfs_client *clp = data->ds_clp;
	int reset = 0;

	dprintk("%s DS read\n", __func__);

	if (filelayout_async_handle_error(task, data->args.context->state,
					  data->ds_clp, &reset) == -EAGAIN) {
		dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
			__func__, data->ds_clp, data->ds_clp->cl_session);
		if (reset) {
			filelayout_set_lo_fail(data->lseg);
			nfs4_reset_read(task, data);
			clp = NFS_SERVER(data->inode)->nfs_client;
		}
		nfs_restart_rpc(task, clp);
		return -EAGAIN;
	}

	return 0;
}

/*
 * We reference the rpc_cred of the first WRITE that triggers the need for
 * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
 * rfc5661 is not clear about which credential should be used.
 */
static void
filelayout_set_layoutcommit(struct nfs_write_data *wdata)
{
	if (FILELAYOUT_LSEG(wdata->lseg)->commit_through_mds ||
	    wdata->res.verf->committed == NFS_FILE_SYNC)
		return;

	pnfs_set_layoutcommit(wdata);
	dprintk("%s ionde %lu pls_end_pos %lu\n", __func__, wdata->inode->i_ino,
		(unsigned long) wdata->lseg->pls_end_pos);
}

/*
 * Call ops for the async read/write cases
 * In the case of dense layouts, the offset needs to be reset to its
 * original value.
 */
static void filelayout_read_prepare(struct rpc_task *task, void *data)
{
	struct nfs_read_data *rdata = (struct nfs_read_data *)data;

	rdata->read_done_cb = filelayout_read_done_cb;

	if (nfs41_setup_sequence(rdata->ds_clp->cl_session,
				&rdata->args.seq_args, &rdata->res.seq_res,
				0, task))
		return;

	rpc_call_start(task);
}

static void filelayout_read_call_done(struct rpc_task *task, void *data)
{
	struct nfs_read_data *rdata = (struct nfs_read_data *)data;

	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);

	/* Note this may cause RPC to be resent */
	rdata->mds_ops->rpc_call_done(task, data);
}

static void filelayout_read_release(void *data)
{
	struct nfs_read_data *rdata = (struct nfs_read_data *)data;

	rdata->mds_ops->rpc_release(data);
}

static int filelayout_write_done_cb(struct rpc_task *task,
				struct nfs_write_data *data)
{
	int reset = 0;

	if (filelayout_async_handle_error(task, data->args.context->state,
					  data->ds_clp, &reset) == -EAGAIN) {
		struct nfs_client *clp;

		dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
			__func__, data->ds_clp, data->ds_clp->cl_session);
		if (reset) {
			filelayout_set_lo_fail(data->lseg);
			nfs4_reset_write(task, data);
			clp = NFS_SERVER(data->inode)->nfs_client;
		} else
			clp = data->ds_clp;
		nfs_restart_rpc(task, clp);
		return -EAGAIN;
	}

	filelayout_set_layoutcommit(data);
	return 0;
}

/* Fake up some data that will cause nfs_commit_release to retry the writes. */
static void prepare_to_resend_writes(struct nfs_write_data *data)
{
	struct nfs_page *first = nfs_list_entry(data->pages.next);

	data->task.tk_status = 0;
	memcpy(data->verf.verifier, first->wb_verf.verifier,
	       sizeof(first->wb_verf.verifier));
	data->verf.verifier[0]++; /* ensure verifier mismatch */
}

static int filelayout_commit_done_cb(struct rpc_task *task,
				     struct nfs_write_data *data)
{
	int reset = 0;

	if (filelayout_async_handle_error(task, data->args.context->state,
					  data->ds_clp, &reset) == -EAGAIN) {
		dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
			__func__, data->ds_clp, data->ds_clp->cl_session);
		if (reset) {
			prepare_to_resend_writes(data);
			filelayout_set_lo_fail(data->lseg);
		} else
			nfs_restart_rpc(task, data->ds_clp);
		return -EAGAIN;
	}

	return 0;
}

static void filelayout_write_prepare(struct rpc_task *task, void *data)
{
	struct nfs_write_data *wdata = (struct nfs_write_data *)data;

	if (nfs41_setup_sequence(wdata->ds_clp->cl_session,
				&wdata->args.seq_args, &wdata->res.seq_res,
				0, task))
		return;

	rpc_call_start(task);
}

static void filelayout_write_call_done(struct rpc_task *task, void *data)
{
	struct nfs_write_data *wdata = (struct nfs_write_data *)data;

	/* Note this may cause RPC to be resent */
	wdata->mds_ops->rpc_call_done(task, data);
}

static void filelayout_write_release(void *data)
{
	struct nfs_write_data *wdata = (struct nfs_write_data *)data;

	wdata->mds_ops->rpc_release(data);
}

static void filelayout_commit_release(void *data)
{
	struct nfs_write_data *wdata = (struct nfs_write_data *)data;

	nfs_commit_release_pages(wdata);
	if (atomic_dec_and_test(&NFS_I(wdata->inode)->commits_outstanding))
		nfs_commit_clear_lock(NFS_I(wdata->inode));
	nfs_commitdata_release(wdata);
}

struct rpc_call_ops filelayout_read_call_ops = {
	.rpc_call_prepare = filelayout_read_prepare,
	.rpc_call_done = filelayout_read_call_done,
	.rpc_release = filelayout_read_release,
};

struct rpc_call_ops filelayout_write_call_ops = {
	.rpc_call_prepare = filelayout_write_prepare,
	.rpc_call_done = filelayout_write_call_done,
	.rpc_release = filelayout_write_release,
};

struct rpc_call_ops filelayout_commit_call_ops = {
	.rpc_call_prepare = filelayout_write_prepare,
	.rpc_call_done = filelayout_write_call_done,
	.rpc_release = filelayout_commit_release,
};

static enum pnfs_try_status
filelayout_read_pagelist(struct nfs_read_data *data)
{
	struct pnfs_layout_segment *lseg = data->lseg;
	struct nfs4_pnfs_ds *ds;
	loff_t offset = data->args.offset;
	u32 j, idx;
	struct nfs_fh *fh;
	int status;

	dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
		__func__, data->inode->i_ino,
		data->args.pgbase, (size_t)data->args.count, offset);

	/* Retrieve the correct rpc_client for the byte range */
	j = nfs4_fl_calc_j_index(lseg, offset);
	idx = nfs4_fl_calc_ds_index(lseg, j);
	ds = nfs4_fl_prepare_ds(lseg, idx);
	if (!ds) {
		/* Either layout fh index faulty, or ds connect failed */
		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
		return PNFS_NOT_ATTEMPTED;
	}
	dprintk("%s USE DS:ip %x %hu\n", __func__,
		ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));

	/* No multipath support. Use first DS */
	data->ds_clp = ds->ds_clp;
	fh = nfs4_fl_select_ds_fh(lseg, j);
	if (fh)
		data->args.fh = fh;

	data->args.offset = filelayout_get_dserver_offset(lseg, offset);
	data->mds_offset = offset;

	/* Perform an asynchronous read to ds */
	status = nfs_initiate_read(data, ds->ds_clp->cl_rpcclient,
				   &filelayout_read_call_ops);
	BUG_ON(status != 0);
	return PNFS_ATTEMPTED;
}

/* Perform async writes. */
static enum pnfs_try_status
filelayout_write_pagelist(struct nfs_write_data *data, int sync)
{
	struct pnfs_layout_segment *lseg = data->lseg;
	struct nfs4_pnfs_ds *ds;
	loff_t offset = data->args.offset;
	u32 j, idx;
	struct nfs_fh *fh;
	int status;

	/* Retrieve the correct rpc_client for the byte range */
	j = nfs4_fl_calc_j_index(lseg, offset);
	idx = nfs4_fl_calc_ds_index(lseg, j);
	ds = nfs4_fl_prepare_ds(lseg, idx);
	if (!ds) {
		printk(KERN_ERR "%s: prepare_ds failed, use MDS\n", __func__);
		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
		return PNFS_NOT_ATTEMPTED;
	}
	dprintk("%s ino %lu sync %d req %Zu@%llu DS:%x:%hu\n", __func__,
		data->inode->i_ino, sync, (size_t) data->args.count, offset,
		ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));

	data->write_done_cb = filelayout_write_done_cb;
	data->ds_clp = ds->ds_clp;
	fh = nfs4_fl_select_ds_fh(lseg, j);
	if (fh)
		data->args.fh = fh;
	/*
	 * Get the file offset on the dserver. Set the write offset to
	 * this offset and save the original offset.
	 */
	data->args.offset = filelayout_get_dserver_offset(lseg, offset);
	data->mds_offset = offset;

	/* Perform an asynchronous write */
	status = nfs_initiate_write(data, ds->ds_clp->cl_rpcclient,
				    &filelayout_write_call_ops, sync);
	BUG_ON(status != 0);
	return PNFS_ATTEMPTED;
}

/*
 * filelayout_check_layout()
 *
 * Make sure layout segment parameters are sane WRT the device.
 * At this point no generic layer initialization of the lseg has occurred,
 * and nothing has been added to the layout_hdr cache.
 *
 */
static int
filelayout_check_layout(struct pnfs_layout_hdr *lo,
			struct nfs4_filelayout_segment *fl,
			struct nfs4_layoutget_res *lgr,
			struct nfs4_deviceid *id,
			gfp_t gfp_flags)
{
	struct nfs4_deviceid_node *d;
	struct nfs4_file_layout_dsaddr *dsaddr;
	int status = -EINVAL;
	struct nfs_server *nfss = NFS_SERVER(lo->plh_inode);

	dprintk("--> %s\n", __func__);

	if (fl->pattern_offset > lgr->range.offset) {
		dprintk("%s pattern_offset %lld too large\n",
				__func__, fl->pattern_offset);
		goto out;
	}

	if (!fl->stripe_unit || fl->stripe_unit % PAGE_SIZE) {
		dprintk("%s Invalid stripe unit (%u)\n",
			__func__, fl->stripe_unit);
		goto out;
	}

	/* find and reference the deviceid */
	d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode)->pnfs_curr_ld,
				   NFS_SERVER(lo->plh_inode)->nfs_client, id);
	if (d == NULL) {
		dsaddr = get_device_info(lo->plh_inode, id, gfp_flags);
		if (dsaddr == NULL)
			goto out;
	} else
		dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
	fl->dsaddr = dsaddr;

	if (fl->first_stripe_index < 0 ||
	    fl->first_stripe_index >= dsaddr->stripe_count) {
		dprintk("%s Bad first_stripe_index %d\n",
				__func__, fl->first_stripe_index);
		goto out_put;
	}

	if ((fl->stripe_type == STRIPE_SPARSE &&
	    fl->num_fh > 1 && fl->num_fh != dsaddr->ds_num) ||
	    (fl->stripe_type == STRIPE_DENSE &&
	    fl->num_fh != dsaddr->stripe_count)) {
		dprintk("%s num_fh %u not valid for given packing\n",
			__func__, fl->num_fh);
		goto out_put;
	}

	if (fl->stripe_unit % nfss->rsize || fl->stripe_unit % nfss->wsize) {
		dprintk("%s Stripe unit (%u) not aligned with rsize %u "
			"wsize %u\n", __func__, fl->stripe_unit, nfss->rsize,
			nfss->wsize);
	}

	status = 0;
out:
	dprintk("--> %s returns %d\n", __func__, status);
	return status;
out_put:
	nfs4_fl_put_deviceid(dsaddr);
	goto out;
}

static void filelayout_free_fh_array(struct nfs4_filelayout_segment *fl)
{
	int i;

	for (i = 0; i < fl->num_fh; i++) {
		if (!fl->fh_array[i])
			break;
		kfree(fl->fh_array[i]);
	}
	kfree(fl->fh_array);
	fl->fh_array = NULL;
}

static void
_filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
{
	filelayout_free_fh_array(fl);
	kfree(fl);
}

static int
filelayout_decode_layout(struct pnfs_layout_hdr *flo,
			 struct nfs4_filelayout_segment *fl,
			 struct nfs4_layoutget_res *lgr,
			 struct nfs4_deviceid *id,
			 gfp_t gfp_flags)
{
	struct xdr_stream stream;
	struct xdr_buf buf;
	struct page *scratch;
	__be32 *p;
	uint32_t nfl_util;
	int i;

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

	scratch = alloc_page(gfp_flags);
	if (!scratch)
		return -ENOMEM;

	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
	xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);

	/* 20 = ufl_util (4), first_stripe_index (4), pattern_offset (8),
	 * num_fh (4) */
	p = xdr_inline_decode(&stream, NFS4_DEVICEID4_SIZE + 20);
	if (unlikely(!p))
		goto out_err;

	memcpy(id, p, sizeof(*id));
	p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
	nfs4_print_deviceid(id);

	nfl_util = be32_to_cpup(p++);
	if (nfl_util & NFL4_UFLG_COMMIT_THRU_MDS)
		fl->commit_through_mds = 1;
	if (nfl_util & NFL4_UFLG_DENSE)
		fl->stripe_type = STRIPE_DENSE;
	else
		fl->stripe_type = STRIPE_SPARSE;
	fl->stripe_unit = nfl_util & ~NFL4_UFLG_MASK;

	fl->first_stripe_index = be32_to_cpup(p++);
	p = xdr_decode_hyper(p, &fl->pattern_offset);
	fl->num_fh = be32_to_cpup(p++);

	dprintk("%s: nfl_util 0x%X num_fh %u fsi %u po %llu\n",
		__func__, nfl_util, fl->num_fh, fl->first_stripe_index,
		fl->pattern_offset);

	/* Note that a zero value for num_fh is legal for STRIPE_SPARSE.
	 * Futher checking is done in filelayout_check_layout */
	if (fl->num_fh < 0 || fl->num_fh >
	    max(NFS4_PNFS_MAX_STRIPE_CNT, NFS4_PNFS_MAX_MULTI_CNT))
		goto out_err;

	if (fl->num_fh > 0) {
		fl->fh_array = kzalloc(fl->num_fh * sizeof(struct nfs_fh *),
				       gfp_flags);
		if (!fl->fh_array)
			goto out_err;
	}

	for (i = 0; i < fl->num_fh; i++) {
		/* Do we want to use a mempool here? */
		fl->fh_array[i] = kmalloc(sizeof(struct nfs_fh), gfp_flags);
		if (!fl->fh_array[i])
			goto out_err_free;

		p = xdr_inline_decode(&stream, 4);
		if (unlikely(!p))
			goto out_err_free;
		fl->fh_array[i]->size = be32_to_cpup(p++);
		if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
			printk(KERN_ERR "Too big fh %d received %d\n",
			       i, fl->fh_array[i]->size);
			goto out_err_free;
		}

		p = xdr_inline_decode(&stream, fl->fh_array[i]->size);
		if (unlikely(!p))
			goto out_err_free;
		memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
		dprintk("DEBUG: %s: fh len %d\n", __func__,
			fl->fh_array[i]->size);
	}

	__free_page(scratch);
	return 0;

out_err_free:
	filelayout_free_fh_array(fl);
out_err:
	__free_page(scratch);
	return -EIO;
}

static void
filelayout_free_lseg(struct pnfs_layout_segment *lseg)
{
	struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);

	dprintk("--> %s\n", __func__);
	nfs4_fl_put_deviceid(fl->dsaddr);
	kfree(fl->commit_buckets);
	_filelayout_free_lseg(fl);
}

static struct pnfs_layout_segment *
filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
		      struct nfs4_layoutget_res *lgr,
		      gfp_t gfp_flags)
{
	struct nfs4_filelayout_segment *fl;
	int rc;
	struct nfs4_deviceid id;

	dprintk("--> %s\n", __func__);
	fl = kzalloc(sizeof(*fl), gfp_flags);
	if (!fl)
		return NULL;

	rc = filelayout_decode_layout(layoutid, fl, lgr, &id, gfp_flags);
	if (rc != 0 || filelayout_check_layout(layoutid, fl, lgr, &id, gfp_flags)) {
		_filelayout_free_lseg(fl);
		return NULL;
	}

	/* This assumes there is only one IOMODE_RW lseg.  What
	 * we really want to do is have a layout_hdr level
	 * dictionary of <multipath_list4, fh> keys, each
	 * associated with a struct list_head, populated by calls
	 * to filelayout_write_pagelist().
	 * */
	if ((!fl->commit_through_mds) && (lgr->range.iomode == IOMODE_RW)) {
		int i;
		int size = (fl->stripe_type == STRIPE_SPARSE) ?
			fl->dsaddr->ds_num : fl->dsaddr->stripe_count;

		fl->commit_buckets = kcalloc(size, sizeof(struct list_head), gfp_flags);
		if (!fl->commit_buckets) {
			filelayout_free_lseg(&fl->generic_hdr);
			return NULL;
		}
		fl->number_of_buckets = size;
		for (i = 0; i < size; i++)
			INIT_LIST_HEAD(&fl->commit_buckets[i]);
	}
	return &fl->generic_hdr;
}

/*
 * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
 *
 * return true  : coalesce page
 * return false : don't coalesce page
 */
bool
filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
		   struct nfs_page *req)
{
	u64 p_stripe, r_stripe;
	u32 stripe_unit;

	if (!pnfs_generic_pg_test(pgio, prev, req) ||
	    !nfs_generic_pg_test(pgio, prev, req))
		return false;

	if (!pgio->pg_lseg)
		return 1;
	p_stripe = (u64)prev->wb_index << PAGE_CACHE_SHIFT;
	r_stripe = (u64)req->wb_index << PAGE_CACHE_SHIFT;
	stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;

	do_div(p_stripe, stripe_unit);
	do_div(r_stripe, stripe_unit);

	return (p_stripe == r_stripe);
}

static bool filelayout_mark_pnfs_commit(struct pnfs_layout_segment *lseg)
{
	return !FILELAYOUT_LSEG(lseg)->commit_through_mds;
}

static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
{
	if (fl->stripe_type == STRIPE_SPARSE)
		return nfs4_fl_calc_ds_index(&fl->generic_hdr, j);
	else
		return j;
}

struct list_head *filelayout_choose_commit_list(struct nfs_page *req)
{
	struct pnfs_layout_segment *lseg = req->wb_commit_lseg;
	struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
	u32 i, j;
	struct list_head *list;

	/* Note that we are calling nfs4_fl_calc_j_index on each page
	 * that ends up being committed to a data server.  An attractive
	 * alternative is to add a field to nfs_write_data and nfs_page
	 * to store the value calculated in filelayout_write_pagelist
	 * and just use that here.
	 */
	j = nfs4_fl_calc_j_index(lseg,
				 (loff_t)req->wb_index << PAGE_CACHE_SHIFT);
	i = select_bucket_index(fl, j);
	list = &fl->commit_buckets[i];
	if (list_empty(list)) {
		/* Non-empty buckets hold a reference on the lseg */
		get_lseg(lseg);
	}
	return list;
}

static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
{
	struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);

	if (flseg->stripe_type == STRIPE_SPARSE)
		return i;
	else
		return nfs4_fl_calc_ds_index(lseg, i);
}

static struct nfs_fh *
select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
{
	struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);

	if (flseg->stripe_type == STRIPE_SPARSE) {
		if (flseg->num_fh == 1)
			i = 0;
		else if (flseg->num_fh == 0)
			/* Use the MDS OPEN fh set in nfs_read_rpcsetup */
			return NULL;
	}
	return flseg->fh_array[i];
}

static int filelayout_initiate_commit(struct nfs_write_data *data, int how)
{
	struct pnfs_layout_segment *lseg = data->lseg;
	struct nfs4_pnfs_ds *ds;
	u32 idx;
	struct nfs_fh *fh;

	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
	ds = nfs4_fl_prepare_ds(lseg, idx);
	if (!ds) {
		printk(KERN_ERR "%s: prepare_ds failed, use MDS\n", __func__);
		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
		prepare_to_resend_writes(data);
		data->mds_ops->rpc_release(data);
		return -EAGAIN;
	}
	dprintk("%s ino %lu, how %d\n", __func__, data->inode->i_ino, how);
	data->write_done_cb = filelayout_commit_done_cb;
	data->ds_clp = ds->ds_clp;
	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
	if (fh)
		data->args.fh = fh;
	return nfs_initiate_commit(data, ds->ds_clp->cl_rpcclient,
				   &filelayout_commit_call_ops, how);
}

/*
 * This is only useful while we are using whole file layouts.
 */
static struct pnfs_layout_segment *find_only_write_lseg(struct inode *inode)
{
	struct pnfs_layout_segment *lseg, *rv = NULL;

	spin_lock(&inode->i_lock);
	list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list)
		if (lseg->pls_range.iomode == IOMODE_RW)
			rv = get_lseg(lseg);
	spin_unlock(&inode->i_lock);
	return rv;
}

static int alloc_ds_commits(struct inode *inode, struct list_head *list)
{
	struct pnfs_layout_segment *lseg;
	struct nfs4_filelayout_segment *fl;
	struct nfs_write_data *data;
	int i, j;

	/* Won't need this when non-whole file layout segments are supported
	 * instead we will use a pnfs_layout_hdr structure */
	lseg = find_only_write_lseg(inode);
	if (!lseg)
		return 0;
	fl = FILELAYOUT_LSEG(lseg);
	for (i = 0; i < fl->number_of_buckets; i++) {
		if (list_empty(&fl->commit_buckets[i]))
			continue;
		data = nfs_commitdata_alloc();
		if (!data)
			goto out_bad;
		data->ds_commit_index = i;
		data->lseg = lseg;
		list_add(&data->pages, list);
	}
	put_lseg(lseg);
	return 0;

out_bad:
	for (j = i; j < fl->number_of_buckets; j++) {
		if (list_empty(&fl->commit_buckets[i]))
			continue;
		nfs_retry_commit(&fl->commit_buckets[i], lseg);
		put_lseg(lseg);  /* associated with emptying bucket */
	}
	put_lseg(lseg);
	/* Caller will clean up entries put on list */
	return -ENOMEM;
}

/* This follows nfs_commit_list pretty closely */
static int
filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
			   int how)
{
	struct nfs_write_data	*data, *tmp;
	LIST_HEAD(list);

	if (!list_empty(mds_pages)) {
		data = nfs_commitdata_alloc();
		if (!data)
			goto out_bad;
		data->lseg = NULL;
		list_add(&data->pages, &list);
	}

	if (alloc_ds_commits(inode, &list))
		goto out_bad;

	list_for_each_entry_safe(data, tmp, &list, pages) {
		list_del_init(&data->pages);
		atomic_inc(&NFS_I(inode)->commits_outstanding);
		if (!data->lseg) {
			nfs_init_commit(data, mds_pages, NULL);
			nfs_initiate_commit(data, NFS_CLIENT(inode),
					    data->mds_ops, how);
		} else {
			nfs_init_commit(data, &FILELAYOUT_LSEG(data->lseg)->commit_buckets[data->ds_commit_index], data->lseg);
			filelayout_initiate_commit(data, how);
		}
	}
	return 0;
 out_bad:
	list_for_each_entry_safe(data, tmp, &list, pages) {
		nfs_retry_commit(&data->pages, data->lseg);
		list_del_init(&data->pages);
		nfs_commit_free(data);
	}
	nfs_retry_commit(mds_pages, NULL);
	nfs_commit_clear_lock(NFS_I(inode));
	return -ENOMEM;
}

static void
filelayout_free_deveiceid_node(struct nfs4_deviceid_node *d)
{
	nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
}

static struct pnfs_layoutdriver_type filelayout_type = {
	.id			= LAYOUT_NFSV4_1_FILES,
	.name			= "LAYOUT_NFSV4_1_FILES",
	.owner			= THIS_MODULE,
	.alloc_lseg		= filelayout_alloc_lseg,
	.free_lseg		= filelayout_free_lseg,
	.pg_test		= filelayout_pg_test,
	.mark_pnfs_commit	= filelayout_mark_pnfs_commit,
	.choose_commit_list	= filelayout_choose_commit_list,
	.commit_pagelist	= filelayout_commit_pagelist,
	.read_pagelist		= filelayout_read_pagelist,
	.write_pagelist		= filelayout_write_pagelist,
	.free_deviceid_node	= filelayout_free_deveiceid_node,
};

static int __init nfs4filelayout_init(void)
{
	printk(KERN_INFO "%s: NFSv4 File Layout Driver Registering...\n",
	       __func__);
	return pnfs_register_layoutdriver(&filelayout_type);
}

static void __exit nfs4filelayout_exit(void)
{
	printk(KERN_INFO "%s: NFSv4 File Layout Driver Unregistering...\n",
	       __func__);
	pnfs_unregister_layoutdriver(&filelayout_type);
}

module_init(nfs4filelayout_init);
module_exit(nfs4filelayout_exit);