summaryrefslogtreecommitdiff
path: root/fs/nfs/objlayout/objio_osd.c
blob: 4e8de3ec9a635db78455f2c0dee88249790f5e4f (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
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
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
/*
 *  pNFS Objects layout implementation over open-osd initiator library
 *
 *  Copyright (C) 2009 Panasas Inc. [year of first publication]
 *  All rights reserved.
 *
 *  Benny Halevy <bhalevy@panasas.com>
 *  Boaz Harrosh <bharrosh@panasas.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  See the file COPYING included with this distribution for more details.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the Panasas company nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/module.h>
#include <scsi/osd_initiator.h>

#include "objlayout.h"

#define NFSDBG_FACILITY         NFSDBG_PNFS_LD

#define _LLU(x) ((unsigned long long)x)

enum { BIO_MAX_PAGES_KMALLOC =
		(PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec),
};

struct objio_dev_ent {
	struct nfs4_deviceid_node id_node;
	struct osd_dev *od;
};

static void
objio_free_deviceid_node(struct nfs4_deviceid_node *d)
{
	struct objio_dev_ent *de = container_of(d, struct objio_dev_ent, id_node);

	dprintk("%s: free od=%p\n", __func__, de->od);
	osduld_put_device(de->od);
	kfree(de);
}

static struct objio_dev_ent *_dev_list_find(const struct nfs_server *nfss,
	const struct nfs4_deviceid *d_id)
{
	struct nfs4_deviceid_node *d;
	struct objio_dev_ent *de;

	d = nfs4_find_get_deviceid(nfss->pnfs_curr_ld, nfss->nfs_client, d_id);
	if (!d)
		return NULL;

	de = container_of(d, struct objio_dev_ent, id_node);
	return de;
}

static struct objio_dev_ent *
_dev_list_add(const struct nfs_server *nfss,
	const struct nfs4_deviceid *d_id, struct osd_dev *od,
	gfp_t gfp_flags)
{
	struct nfs4_deviceid_node *d;
	struct objio_dev_ent *de = kzalloc(sizeof(*de), gfp_flags);
	struct objio_dev_ent *n;

	if (!de) {
		dprintk("%s: -ENOMEM od=%p\n", __func__, od);
		return NULL;
	}

	dprintk("%s: Adding od=%p\n", __func__, od);
	nfs4_init_deviceid_node(&de->id_node,
				nfss->pnfs_curr_ld,
				nfss->nfs_client,
				d_id);
	de->od = od;

	d = nfs4_insert_deviceid_node(&de->id_node);
	n = container_of(d, struct objio_dev_ent, id_node);
	if (n != de) {
		dprintk("%s: Race with other n->od=%p\n", __func__, n->od);
		objio_free_deviceid_node(&de->id_node);
		de = n;
	}

	atomic_inc(&de->id_node.ref);
	return de;
}

struct caps_buffers {
	u8 caps_key[OSD_CRYPTO_KEYID_SIZE];
	u8 creds[OSD_CAP_LEN];
};

struct objio_segment {
	struct pnfs_layout_segment lseg;

	struct pnfs_osd_object_cred *comps;

	unsigned mirrors_p1;
	unsigned stripe_unit;
	unsigned group_width;	/* Data stripe_units without integrity comps */
	u64 group_depth;
	unsigned group_count;

	unsigned comps_index;
	unsigned num_comps;
	/* variable length */
	struct objio_dev_ent *ods[];
};

static inline struct objio_segment *
OBJIO_LSEG(struct pnfs_layout_segment *lseg)
{
	return container_of(lseg, struct objio_segment, lseg);
}

struct objio_state;
typedef ssize_t (*objio_done_fn)(struct objio_state *ios);

struct objio_state {
	/* Generic layer */
	struct objlayout_io_state ol_state;

	struct objio_segment *layout;

	struct kref kref;
	objio_done_fn done;
	void *private;

	unsigned long length;
	unsigned numdevs; /* Actually used devs in this IO */
	/* A per-device variable array of size numdevs */
	struct _objio_per_comp {
		struct bio *bio;
		struct osd_request *or;
		unsigned long length;
		u64 offset;
		unsigned dev;
	} per_dev[];
};

/* Send and wait for a get_device_info of devices in the layout,
   then look them up with the osd_initiator library */
static struct objio_dev_ent *_device_lookup(struct pnfs_layout_hdr *pnfslay,
				struct objio_segment *objio_seg, unsigned comp,
				gfp_t gfp_flags)
{
	struct pnfs_osd_deviceaddr *deviceaddr;
	struct nfs4_deviceid *d_id;
	struct objio_dev_ent *ode;
	struct osd_dev *od;
	struct osd_dev_info odi;
	int err;

	d_id = &objio_seg->comps[comp].oc_object_id.oid_device_id;

	ode = _dev_list_find(NFS_SERVER(pnfslay->plh_inode), d_id);
	if (ode)
		return ode;

	err = objlayout_get_deviceinfo(pnfslay, d_id, &deviceaddr, gfp_flags);
	if (unlikely(err)) {
		dprintk("%s: objlayout_get_deviceinfo dev(%llx:%llx) =>%d\n",
			__func__, _DEVID_LO(d_id), _DEVID_HI(d_id), err);
		return ERR_PTR(err);
	}

	odi.systemid_len = deviceaddr->oda_systemid.len;
	if (odi.systemid_len > sizeof(odi.systemid)) {
		err = -EINVAL;
		goto out;
	} else if (odi.systemid_len)
		memcpy(odi.systemid, deviceaddr->oda_systemid.data,
		       odi.systemid_len);
	odi.osdname_len	 = deviceaddr->oda_osdname.len;
	odi.osdname	 = (u8 *)deviceaddr->oda_osdname.data;

	if (!odi.osdname_len && !odi.systemid_len) {
		dprintk("%s: !odi.osdname_len && !odi.systemid_len\n",
			__func__);
		err = -ENODEV;
		goto out;
	}

	od = osduld_info_lookup(&odi);
	if (unlikely(IS_ERR(od))) {
		err = PTR_ERR(od);
		dprintk("%s: osduld_info_lookup => %d\n", __func__, err);
		goto out;
	}

	ode = _dev_list_add(NFS_SERVER(pnfslay->plh_inode), d_id, od,
			    gfp_flags);

out:
	dprintk("%s: return=%d\n", __func__, err);
	objlayout_put_deviceinfo(deviceaddr);
	return err ? ERR_PTR(err) : ode;
}

static int objio_devices_lookup(struct pnfs_layout_hdr *pnfslay,
	struct objio_segment *objio_seg,
	gfp_t gfp_flags)
{
	unsigned i;
	int err;

	/* lookup all devices */
	for (i = 0; i < objio_seg->num_comps; i++) {
		struct objio_dev_ent *ode;

		ode = _device_lookup(pnfslay, objio_seg, i, gfp_flags);
		if (unlikely(IS_ERR(ode))) {
			err = PTR_ERR(ode);
			goto out;
		}
		objio_seg->ods[i] = ode;
	}
	err = 0;

out:
	dprintk("%s: return=%d\n", __func__, err);
	return err;
}

static int _verify_data_map(struct pnfs_osd_layout *layout)
{
	struct pnfs_osd_data_map *data_map = &layout->olo_map;
	u64 stripe_length;
	u32 group_width;

/* FIXME: Only raid0 for now. if not go through MDS */
	if (data_map->odm_raid_algorithm != PNFS_OSD_RAID_0) {
		printk(KERN_ERR "Only RAID_0 for now\n");
		return -ENOTSUPP;
	}
	if (0 != (data_map->odm_num_comps % (data_map->odm_mirror_cnt + 1))) {
		printk(KERN_ERR "Data Map wrong, num_comps=%u mirrors=%u\n",
			  data_map->odm_num_comps, data_map->odm_mirror_cnt);
		return -EINVAL;
	}

	if (data_map->odm_group_width)
		group_width = data_map->odm_group_width;
	else
		group_width = data_map->odm_num_comps /
						(data_map->odm_mirror_cnt + 1);

	stripe_length = (u64)data_map->odm_stripe_unit * group_width;
	if (stripe_length >= (1ULL << 32)) {
		printk(KERN_ERR "Total Stripe length(0x%llx)"
			  " >= 32bit is not supported\n", _LLU(stripe_length));
		return -ENOTSUPP;
	}

	if (0 != (data_map->odm_stripe_unit & ~PAGE_MASK)) {
		printk(KERN_ERR "Stripe Unit(0x%llx)"
			  " must be Multples of PAGE_SIZE(0x%lx)\n",
			  _LLU(data_map->odm_stripe_unit), PAGE_SIZE);
		return -ENOTSUPP;
	}

	return 0;
}

static void copy_single_comp(struct pnfs_osd_object_cred *cur_comp,
			     struct pnfs_osd_object_cred *src_comp,
			     struct caps_buffers *caps_p)
{
	WARN_ON(src_comp->oc_cap_key.cred_len > sizeof(caps_p->caps_key));
	WARN_ON(src_comp->oc_cap.cred_len > sizeof(caps_p->creds));

	*cur_comp = *src_comp;

	memcpy(caps_p->caps_key, src_comp->oc_cap_key.cred,
	       sizeof(caps_p->caps_key));
	cur_comp->oc_cap_key.cred = caps_p->caps_key;

	memcpy(caps_p->creds, src_comp->oc_cap.cred,
	       sizeof(caps_p->creds));
	cur_comp->oc_cap.cred = caps_p->creds;
}

int objio_alloc_lseg(struct pnfs_layout_segment **outp,
	struct pnfs_layout_hdr *pnfslay,
	struct pnfs_layout_range *range,
	struct xdr_stream *xdr,
	gfp_t gfp_flags)
{
	struct objio_segment *objio_seg;
	struct pnfs_osd_xdr_decode_layout_iter iter;
	struct pnfs_osd_layout layout;
	struct pnfs_osd_object_cred *cur_comp, src_comp;
	struct caps_buffers *caps_p;
	int err;

	err = pnfs_osd_xdr_decode_layout_map(&layout, &iter, xdr);
	if (unlikely(err))
		return err;

	err = _verify_data_map(&layout);
	if (unlikely(err))
		return err;

	objio_seg = kzalloc(sizeof(*objio_seg) +
			    sizeof(objio_seg->ods[0]) * layout.olo_num_comps +
			    sizeof(*objio_seg->comps) * layout.olo_num_comps +
			    sizeof(struct caps_buffers) * layout.olo_num_comps,
			    gfp_flags);
	if (!objio_seg)
		return -ENOMEM;

	objio_seg->comps = (void *)(objio_seg->ods + layout.olo_num_comps);
	cur_comp = objio_seg->comps;
	caps_p = (void *)(cur_comp + layout.olo_num_comps);
	while (pnfs_osd_xdr_decode_layout_comp(&src_comp, &iter, xdr, &err))
		copy_single_comp(cur_comp++, &src_comp, caps_p++);
	if (unlikely(err))
		goto err;

	objio_seg->num_comps = layout.olo_num_comps;
	objio_seg->comps_index = layout.olo_comps_index;
	err = objio_devices_lookup(pnfslay, objio_seg, gfp_flags);
	if (err)
		goto err;

	objio_seg->mirrors_p1 = layout.olo_map.odm_mirror_cnt + 1;
	objio_seg->stripe_unit = layout.olo_map.odm_stripe_unit;
	if (layout.olo_map.odm_group_width) {
		objio_seg->group_width = layout.olo_map.odm_group_width;
		objio_seg->group_depth = layout.olo_map.odm_group_depth;
		objio_seg->group_count = layout.olo_map.odm_num_comps /
						objio_seg->mirrors_p1 /
						objio_seg->group_width;
	} else {
		objio_seg->group_width = layout.olo_map.odm_num_comps /
						objio_seg->mirrors_p1;
		objio_seg->group_depth = -1;
		objio_seg->group_count = 1;
	}

	*outp = &objio_seg->lseg;
	return 0;

err:
	kfree(objio_seg);
	dprintk("%s: Error: return %d\n", __func__, err);
	*outp = NULL;
	return err;
}

void objio_free_lseg(struct pnfs_layout_segment *lseg)
{
	int i;
	struct objio_segment *objio_seg = OBJIO_LSEG(lseg);

	for (i = 0; i < objio_seg->num_comps; i++) {
		if (!objio_seg->ods[i])
			break;
		nfs4_put_deviceid_node(&objio_seg->ods[i]->id_node);
	}
	kfree(objio_seg);
}

int objio_alloc_io_state(struct pnfs_layout_segment *lseg,
			 struct objlayout_io_state **outp,
			 gfp_t gfp_flags)
{
	struct objio_segment *objio_seg = OBJIO_LSEG(lseg);
	struct objio_state *ios;
	const unsigned first_size = sizeof(*ios) +
				objio_seg->num_comps * sizeof(ios->per_dev[0]);

	ios = kzalloc(first_size, gfp_flags);
	if (unlikely(!ios))
		return -ENOMEM;

	ios->layout = objio_seg;

	*outp = &ios->ol_state;
	return 0;
}

void objio_free_io_state(struct objlayout_io_state *ol_state)
{
	struct objio_state *ios = container_of(ol_state, struct objio_state,
					       ol_state);

	kfree(ios);
}

static void _clear_bio(struct bio *bio)
{
	struct bio_vec *bv;
	unsigned i;

	__bio_for_each_segment(bv, bio, i, 0) {
		unsigned this_count = bv->bv_len;

		if (likely(PAGE_SIZE == this_count))
			clear_highpage(bv->bv_page);
		else
			zero_user(bv->bv_page, bv->bv_offset, this_count);
	}
}

static int _io_check(struct objio_state *ios, bool is_write)
{
	enum osd_err_priority oep = OSD_ERR_PRI_NO_ERROR;
	int lin_ret = 0;
	int i;

	for (i = 0; i <  ios->numdevs; i++) {
		struct osd_sense_info osi;
		struct osd_request *or = ios->per_dev[i].or;
		unsigned dev;
		int ret;

		if (!or)
			continue;

		ret = osd_req_decode_sense(or, &osi);
		if (likely(!ret))
			continue;

		if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
			/* start read offset passed endof file */
			BUG_ON(is_write);
			_clear_bio(ios->per_dev[i].bio);
			dprintk("%s: start read offset passed end of file "
				"offset=0x%llx, length=0x%lx\n", __func__,
				_LLU(ios->per_dev[i].offset),
				ios->per_dev[i].length);

			continue; /* we recovered */
		}
		dev = ios->per_dev[i].dev;

		if (osi.osd_err_pri >= oep) {
			oep = osi.osd_err_pri;
			lin_ret = ret;
		}
	}

	return lin_ret;
}

/*
 * Common IO state helpers.
 */
static void _io_free(struct objio_state *ios)
{
	unsigned i;

	for (i = 0; i < ios->numdevs; i++) {
		struct _objio_per_comp *per_dev = &ios->per_dev[i];

		if (per_dev->or) {
			osd_end_request(per_dev->or);
			per_dev->or = NULL;
		}

		if (per_dev->bio) {
			bio_put(per_dev->bio);
			per_dev->bio = NULL;
		}
	}
}

struct osd_dev *_io_od(struct objio_state *ios, unsigned dev)
{
	unsigned min_dev = ios->layout->comps_index;
	unsigned max_dev = min_dev + ios->layout->num_comps;

	BUG_ON(dev < min_dev || max_dev <= dev);
	return ios->layout->ods[dev - min_dev]->od;
}

struct _striping_info {
	u64 obj_offset;
	u64 group_length;
	unsigned dev;
	unsigned unit_off;
};

static void _calc_stripe_info(struct objio_state *ios, u64 file_offset,
			      struct _striping_info *si)
{
	u32	stripe_unit = ios->layout->stripe_unit;
	u32	group_width = ios->layout->group_width;
	u64	group_depth = ios->layout->group_depth;
	u32	U = stripe_unit * group_width;

	u64	T = U * group_depth;
	u64	S = T * ios->layout->group_count;
	u64	M = div64_u64(file_offset, S);

	/*
	G = (L - (M * S)) / T
	H = (L - (M * S)) % T
	*/
	u64	LmodU = file_offset - M * S;
	u32	G = div64_u64(LmodU, T);
	u64	H = LmodU - G * T;

	u32	N = div_u64(H, U);

	div_u64_rem(file_offset, stripe_unit, &si->unit_off);
	si->obj_offset = si->unit_off + (N * stripe_unit) +
				  (M * group_depth * stripe_unit);

	/* "H - (N * U)" is just "H % U" so it's bound to u32 */
	si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
	si->dev *= ios->layout->mirrors_p1;

	si->group_length = T - H;
}

static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
		unsigned pgbase, struct _objio_per_comp *per_dev, int cur_len,
		gfp_t gfp_flags)
{
	unsigned pg = *cur_pg;
	struct request_queue *q =
			osd_request_queue(_io_od(ios, per_dev->dev));

	per_dev->length += cur_len;

	if (per_dev->bio == NULL) {
		unsigned stripes = ios->layout->num_comps /
						     ios->layout->mirrors_p1;
		unsigned pages_in_stripe = stripes *
				      (ios->layout->stripe_unit / PAGE_SIZE);
		unsigned bio_size = (ios->ol_state.nr_pages + pages_in_stripe) /
				    stripes;

		if (BIO_MAX_PAGES_KMALLOC < bio_size)
			bio_size = BIO_MAX_PAGES_KMALLOC;

		per_dev->bio = bio_kmalloc(gfp_flags, bio_size);
		if (unlikely(!per_dev->bio)) {
			dprintk("Faild to allocate BIO size=%u\n", bio_size);
			return -ENOMEM;
		}
	}

	while (cur_len > 0) {
		unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
		unsigned added_len;

		BUG_ON(ios->ol_state.nr_pages <= pg);
		cur_len -= pglen;

		added_len = bio_add_pc_page(q, per_dev->bio,
					ios->ol_state.pages[pg], pglen, pgbase);
		if (unlikely(pglen != added_len))
			return -ENOMEM;
		pgbase = 0;
		++pg;
	}
	BUG_ON(cur_len);

	*cur_pg = pg;
	return 0;
}

static int _prepare_one_group(struct objio_state *ios, u64 length,
			      struct _striping_info *si, unsigned *last_pg,
			      gfp_t gfp_flags)
{
	unsigned stripe_unit = ios->layout->stripe_unit;
	unsigned mirrors_p1 = ios->layout->mirrors_p1;
	unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
	unsigned dev = si->dev;
	unsigned first_dev = dev - (dev % devs_in_group);
	unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;
	unsigned cur_pg = *last_pg;
	int ret = 0;

	while (length) {
		struct _objio_per_comp *per_dev = &ios->per_dev[dev];
		unsigned cur_len, page_off = 0;

		if (!per_dev->length) {
			per_dev->dev = dev;
			if (dev < si->dev) {
				per_dev->offset = si->obj_offset + stripe_unit -
								   si->unit_off;
				cur_len = stripe_unit;
			} else if (dev == si->dev) {
				per_dev->offset = si->obj_offset;
				cur_len = stripe_unit - si->unit_off;
				page_off = si->unit_off & ~PAGE_MASK;
				BUG_ON(page_off &&
				      (page_off != ios->ol_state.pgbase));
			} else { /* dev > si->dev */
				per_dev->offset = si->obj_offset - si->unit_off;
				cur_len = stripe_unit;
			}

			if (max_comp < dev)
				max_comp = dev;
		} else {
			cur_len = stripe_unit;
		}
		if (cur_len >= length)
			cur_len = length;

		ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
				       cur_len, gfp_flags);
		if (unlikely(ret))
			goto out;

		dev += mirrors_p1;
		dev = (dev % devs_in_group) + first_dev;

		length -= cur_len;
		ios->length += cur_len;
	}
out:
	ios->numdevs = max_comp + mirrors_p1;
	*last_pg = cur_pg;
	return ret;
}

static int _io_rw_pagelist(struct objio_state *ios, gfp_t gfp_flags)
{
	u64 length = ios->ol_state.count;
	u64 offset = ios->ol_state.offset;
	struct _striping_info si;
	unsigned last_pg = 0;
	int ret = 0;

	while (length) {
		_calc_stripe_info(ios, offset, &si);

		if (length < si.group_length)
			si.group_length = length;

		ret = _prepare_one_group(ios, si.group_length, &si, &last_pg, gfp_flags);
		if (unlikely(ret))
			goto out;

		offset += si.group_length;
		length -= si.group_length;
	}

out:
	if (!ios->length)
		return ret;

	return 0;
}

static ssize_t _sync_done(struct objio_state *ios)
{
	struct completion *waiting = ios->private;

	complete(waiting);
	return 0;
}

static void _last_io(struct kref *kref)
{
	struct objio_state *ios = container_of(kref, struct objio_state, kref);

	ios->done(ios);
}

static void _done_io(struct osd_request *or, void *p)
{
	struct objio_state *ios = p;

	kref_put(&ios->kref, _last_io);
}

static ssize_t _io_exec(struct objio_state *ios)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	ssize_t status = 0; /* sync status */
	unsigned i;
	objio_done_fn saved_done_fn = ios->done;
	bool sync = ios->ol_state.sync;

	if (sync) {
		ios->done = _sync_done;
		ios->private = &wait;
	}

	kref_init(&ios->kref);

	for (i = 0; i < ios->numdevs; i++) {
		struct osd_request *or = ios->per_dev[i].or;

		if (!or)
			continue;

		kref_get(&ios->kref);
		osd_execute_request_async(or, _done_io, ios);
	}

	kref_put(&ios->kref, _last_io);

	if (sync) {
		wait_for_completion(&wait);
		status = saved_done_fn(ios);
	}

	return status;
}

/*
 * read
 */
static ssize_t _read_done(struct objio_state *ios)
{
	ssize_t status;
	int ret = _io_check(ios, false);

	_io_free(ios);

	if (likely(!ret))
		status = ios->length;
	else
		status = ret;

	objlayout_read_done(&ios->ol_state, status, ios->ol_state.sync);
	return status;
}

static int _read_mirrors(struct objio_state *ios, unsigned cur_comp)
{
	struct osd_request *or = NULL;
	struct _objio_per_comp *per_dev = &ios->per_dev[cur_comp];
	unsigned dev = per_dev->dev;
	struct pnfs_osd_object_cred *cred =
			&ios->layout->comps[dev];
	struct osd_obj_id obj = {
		.partition = cred->oc_object_id.oid_partition_id,
		.id = cred->oc_object_id.oid_object_id,
	};
	int ret;

	or = osd_start_request(_io_od(ios, dev), GFP_KERNEL);
	if (unlikely(!or)) {
		ret = -ENOMEM;
		goto err;
	}
	per_dev->or = or;

	osd_req_read(or, &obj, per_dev->offset, per_dev->bio, per_dev->length);

	ret = osd_finalize_request(or, 0, cred->oc_cap.cred, NULL);
	if (ret) {
		dprintk("%s: Faild to osd_finalize_request() => %d\n",
			__func__, ret);
		goto err;
	}

	dprintk("%s:[%d] dev=%d obj=0x%llx start=0x%llx length=0x%lx\n",
		__func__, cur_comp, dev, obj.id, _LLU(per_dev->offset),
		per_dev->length);

err:
	return ret;
}

static ssize_t _read_exec(struct objio_state *ios)
{
	unsigned i;
	int ret;

	for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
		if (!ios->per_dev[i].length)
			continue;
		ret = _read_mirrors(ios, i);
		if (unlikely(ret))
			goto err;
	}

	ios->done = _read_done;
	return _io_exec(ios); /* In sync mode exec returns the io status */

err:
	_io_free(ios);
	return ret;
}

ssize_t objio_read_pagelist(struct objlayout_io_state *ol_state)
{
	struct objio_state *ios = container_of(ol_state, struct objio_state,
					       ol_state);
	int ret;

	ret = _io_rw_pagelist(ios, GFP_KERNEL);
	if (unlikely(ret))
		return ret;

	return _read_exec(ios);
}

/*
 * write
 */
static ssize_t _write_done(struct objio_state *ios)
{
	ssize_t status;
	int ret = _io_check(ios, true);

	_io_free(ios);

	if (likely(!ret)) {
		/* FIXME: should be based on the OSD's persistence model
		 * See OSD2r05 Section 4.13 Data persistence model */
		ios->ol_state.committed = NFS_FILE_SYNC;
		status = ios->length;
	} else {
		status = ret;
	}

	objlayout_write_done(&ios->ol_state, status, ios->ol_state.sync);
	return status;
}

static int _write_mirrors(struct objio_state *ios, unsigned cur_comp)
{
	struct _objio_per_comp *master_dev = &ios->per_dev[cur_comp];
	unsigned dev = ios->per_dev[cur_comp].dev;
	unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
	int ret;

	for (; cur_comp < last_comp; ++cur_comp, ++dev) {
		struct osd_request *or = NULL;
		struct pnfs_osd_object_cred *cred =
					&ios->layout->comps[dev];
		struct osd_obj_id obj = {
			.partition = cred->oc_object_id.oid_partition_id,
			.id = cred->oc_object_id.oid_object_id,
		};
		struct _objio_per_comp *per_dev = &ios->per_dev[cur_comp];
		struct bio *bio;

		or = osd_start_request(_io_od(ios, dev), GFP_NOFS);
		if (unlikely(!or)) {
			ret = -ENOMEM;
			goto err;
		}
		per_dev->or = or;

		if (per_dev != master_dev) {
			bio = bio_kmalloc(GFP_NOFS,
					  master_dev->bio->bi_max_vecs);
			if (unlikely(!bio)) {
				dprintk("Faild to allocate BIO size=%u\n",
					master_dev->bio->bi_max_vecs);
				ret = -ENOMEM;
				goto err;
			}

			__bio_clone(bio, master_dev->bio);
			bio->bi_bdev = NULL;
			bio->bi_next = NULL;
			per_dev->bio = bio;
			per_dev->dev = dev;
			per_dev->length = master_dev->length;
			per_dev->offset =  master_dev->offset;
		} else {
			bio = master_dev->bio;
			bio->bi_rw |= REQ_WRITE;
		}

		osd_req_write(or, &obj, per_dev->offset, bio, per_dev->length);

		ret = osd_finalize_request(or, 0, cred->oc_cap.cred, NULL);
		if (ret) {
			dprintk("%s: Faild to osd_finalize_request() => %d\n",
				__func__, ret);
			goto err;
		}

		dprintk("%s:[%d] dev=%d obj=0x%llx start=0x%llx length=0x%lx\n",
			__func__, cur_comp, dev, obj.id, _LLU(per_dev->offset),
			per_dev->length);
	}

err:
	return ret;
}

static ssize_t _write_exec(struct objio_state *ios)
{
	unsigned i;
	int ret;

	for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
		if (!ios->per_dev[i].length)
			continue;
		ret = _write_mirrors(ios, i);
		if (unlikely(ret))
			goto err;
	}

	ios->done = _write_done;
	return _io_exec(ios); /* In sync mode exec returns the io->status */

err:
	_io_free(ios);
	return ret;
}

ssize_t objio_write_pagelist(struct objlayout_io_state *ol_state, bool stable)
{
	struct objio_state *ios = container_of(ol_state, struct objio_state,
					       ol_state);
	int ret;

	/* TODO: ios->stable = stable; */
	ret = _io_rw_pagelist(ios, GFP_NOFS);
	if (unlikely(ret))
		return ret;

	return _write_exec(ios);
}

/*
 * objlayout_pg_test(). Called by nfs_can_coalesce_requests()
 *
 * return 1 :  coalesce page
 * return 0 :  don't coalesce page
 */
int
objlayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
		   struct nfs_page *req)
{
	return 1;
}

static struct pnfs_layoutdriver_type objlayout_type = {
	.id = LAYOUT_OSD2_OBJECTS,
	.name = "LAYOUT_OSD2_OBJECTS",
	.flags                   = PNFS_LAYOUTRET_ON_SETATTR,

	.alloc_layout_hdr        = objlayout_alloc_layout_hdr,
	.free_layout_hdr         = objlayout_free_layout_hdr,

	.alloc_lseg              = objlayout_alloc_lseg,
	.free_lseg               = objlayout_free_lseg,

	.read_pagelist           = objlayout_read_pagelist,
	.write_pagelist          = objlayout_write_pagelist,
	.pg_test                 = objlayout_pg_test,

	.free_deviceid_node	 = objio_free_deviceid_node,
};

MODULE_DESCRIPTION("pNFS Layout Driver for OSD2 objects");
MODULE_AUTHOR("Benny Halevy <bhalevy@panasas.com>");
MODULE_LICENSE("GPL");

static int __init
objlayout_init(void)
{
	int ret = pnfs_register_layoutdriver(&objlayout_type);

	if (ret)
		printk(KERN_INFO
			"%s: Registering OSD pNFS Layout Driver failed: error=%d\n",
			__func__, ret);
	else
		printk(KERN_INFO "%s: Registered OSD pNFS Layout Driver\n",
			__func__);
	return ret;
}

static void __exit
objlayout_exit(void)
{
	pnfs_unregister_layoutdriver(&objlayout_type);
	printk(KERN_INFO "%s: Unregistered OSD pNFS Layout Driver\n",
	       __func__);
}

module_init(objlayout_init);
module_exit(objlayout_exit);