summaryrefslogtreecommitdiffstats
path: root/drivers/block/osdblk.c
blob: 6cd8b705b11be399bca98b3ca44f503c68fbbf98 (plain) (blame)
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

/*
   osdblk.c -- Export a single SCSI OSD object as a Linux block device


   Copyright 2009 Red Hat, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


   Instructions for use
   --------------------

   1) Map a Linux block device to an existing OSD object.

      In this example, we will use partition id 1234, object id 5678,
      OSD device /dev/osd1.

      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add


   2) List all active blkdev<->object mappings.

      In this example, we have performed step #1 twice, creating two blkdevs,
      mapped to two separate OSD objects.

      $ cat /sys/class/osdblk/list
      0 174 1234 5678 /dev/osd1
      1 179 1994 897123 /dev/osd0

      The columns, in order, are:
      - blkdev unique id
      - blkdev assigned major
      - OSD object partition id
      - OSD object id
      - OSD device


   3) Remove an active blkdev<->object mapping.

      In this example, we remove the mapping with blkdev unique id 1.

      $ echo 1 > /sys/class/osdblk/remove


   NOTE:  The actual creation and deletion of OSD objects is outside the scope
   of this driver.

 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <scsi/osd_initiator.h>
#include <scsi/osd_attributes.h>
#include <scsi/osd_sec.h>
#include <scsi/scsi_device.h>

#define DRV_NAME "osdblk"
#define PFX DRV_NAME ": "

/* #define _OSDBLK_DEBUG */
#ifdef _OSDBLK_DEBUG
#define OSDBLK_DEBUG(fmt, a...) \
	printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a)
#else
#define OSDBLK_DEBUG(fmt, a...) \
	do { if (0) printk(fmt, ##a); } while (0)
#endif

MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
MODULE_LICENSE("GPL");

struct osdblk_device;

enum {
	OSDBLK_MINORS_PER_MAJOR	= 256,		/* max minors per blkdev */
	OSDBLK_MAX_REQ		= 32,		/* max parallel requests */
	OSDBLK_OP_TIMEOUT	= 4 * 60,	/* sync OSD req timeout */
};

struct osdblk_request {
	struct request		*rq;		/* blk layer request */
	struct bio		*bio;		/* cloned bio */
	struct osdblk_device	*osdev;		/* associated blkdev */
};

struct osdblk_device {
	int			id;		/* blkdev unique id */

	int			major;		/* blkdev assigned major */
	struct gendisk		*disk;		/* blkdev's gendisk and rq */
	struct request_queue	*q;

	struct osd_dev		*osd;		/* associated OSD */

	char			name[32];	/* blkdev name, e.g. osdblk34 */

	spinlock_t		lock;		/* queue lock */

	struct osd_obj_id	obj;		/* OSD partition, obj id */
	uint8_t			obj_cred[OSD_CAP_LEN]; /* OSD cred */

	struct osdblk_request	req[OSDBLK_MAX_REQ]; /* request table */

	struct list_head	node;

	char			osd_path[0];	/* OSD device path */
};

static struct class *class_osdblk;		/* /sys/class/osdblk */
static DEFINE_MUTEX(ctl_mutex);	/* Serialize open/close/setup/teardown */
static LIST_HEAD(osdblkdev_list);

static const struct block_device_operations osdblk_bd_ops = {
	.owner		= THIS_MODULE,
};

static const struct osd_attr g_attr_logical_length = ATTR_DEF(
	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);

static void osdblk_make_credential(u8 cred_a[OSD_CAP_LEN],
				   const struct osd_obj_id *obj)
{
	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
}

/* copied from exofs; move to libosd? */
/*
 * Perform a synchronous OSD operation.  copied from exofs; move to libosd?
 */
static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
{
	int ret;

	or->timeout = timeout;
	ret = osd_finalize_request(or, 0, credential, NULL);
	if (ret)
		return ret;

	ret = osd_execute_request(or);

	/* osd_req_decode_sense(or, ret); */
	return ret;
}

/*
 * Perform an asynchronous OSD operation.  copied from exofs; move to libosd?
 */
static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
		   void *caller_context, u8 *cred)
{
	int ret;

	ret = osd_finalize_request(or, 0, cred, NULL);
	if (ret)
		return ret;

	ret = osd_execute_request_async(or, async_done, caller_context);

	return ret;
}

/* copied from exofs; move to libosd? */
static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
{
	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
	void *iter = NULL;
	int nelem;

	do {
		nelem = 1;
		osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
		if ((cur_attr.attr_page == attr->attr_page) &&
		    (cur_attr.attr_id == attr->attr_id)) {
			attr->len = cur_attr.len;
			attr->val_ptr = cur_attr.val_ptr;
			return 0;
		}
	} while (iter);

	return -EIO;
}

static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
{
	struct osd_request *or;
	struct osd_attr attr;
	int ret;

	/* start request */
	or = osd_start_request(osdev->osd, GFP_KERNEL);
	if (!or)
		return -ENOMEM;

	/* create a get-attributes(length) request */
	osd_req_get_attributes(or, &osdev->obj);

	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);

	/* execute op synchronously */
	ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
	if (ret)
		goto out;

	/* extract length from returned attribute info */
	attr = g_attr_logical_length;
	ret = extract_attr_from_req(or, &attr);
	if (ret)
		goto out;

	*size_out = get_unaligned_be64(attr.val_ptr);

out:
	osd_end_request(or);
	return ret;

}

static void osdblk_osd_complete(struct osd_request *or, void *private)
{
	struct osdblk_request *orq = private;
	struct osd_sense_info osi;
	int ret = osd_req_decode_sense(or, &osi);

	if (ret) {
		ret = -EIO;
		OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret);
	}

	/* complete OSD request */
	osd_end_request(or);

	/* complete request passed to osdblk by block layer */
	__blk_end_request_all(orq->rq, ret);
}

static void bio_chain_put(struct bio *chain)
{
	struct bio *tmp;

	while (chain) {
		tmp = chain;
		chain = chain->bi_next;

		bio_put(tmp);
	}
}

static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
{
	struct bio *tmp, *new_chain = NULL, *tail = NULL;

	while (old_chain) {
		tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
		if (!tmp)
			goto err_out;

		__bio_clone(tmp, old_chain);
		tmp->bi_bdev = NULL;
		gfpmask &= ~__GFP_WAIT;
		tmp->bi_next = NULL;

		if (!new_chain)
			new_chain = tail = tmp;
		else {
			tail->bi_next = tmp;
			tail = tmp;
		}

		old_chain = old_chain->bi_next;
	}

	return new_chain;

err_out:
	OSDBLK_DEBUG("bio_chain_clone with err\n");
	bio_chain_put(new_chain);
	return NULL;
}

static void osdblk_rq_fn(struct request_queue *q)
{
	struct osdblk_device *osdev = q->queuedata;

	while (1) {
		struct request *rq;
		struct osdblk_request *orq;
		struct osd_request *or;
		struct bio *bio;
		bool do_write, do_flush;

		/* peek at request from block layer */
		rq = blk_fetch_request(q);
		if (!rq)
			break;

		/* filter out block requests we don't understand */
		if (!blk_fs_request(rq) && !blk_barrier_rq(rq)) {
			blk_end_request_all(rq, 0);
			continue;
		}

		/* deduce our operation (read, write, flush) */
		/* I wish the block layer simplified cmd_type/cmd_flags/cmd[]
		 * into a clearly defined set of RPC commands:
		 * read, write, flush, scsi command, power mgmt req,
		 * driver-specific, etc.
		 */

		do_flush = (rq->special == (void *) 0xdeadbeefUL);
		do_write = (rq_data_dir(rq) == WRITE);

		if (!do_flush) { /* osd_flush does not use a bio */
			/* a bio clone to be passed down to OSD request */
			bio = bio_chain_clone(rq->bio, GFP_ATOMIC);
			if (!bio)
				break;
		} else
			bio = NULL;

		/* alloc internal OSD request, for OSD command execution */
		or = osd_start_request(osdev->osd, GFP_ATOMIC);
		if (!or) {
			bio_chain_put(bio);
			OSDBLK_DEBUG("osd_start_request with err\n");
			break;
		}

		orq = &osdev->req[rq->tag];
		orq->rq = rq;
		orq->bio = bio;
		orq->osdev = osdev;

		/* init OSD command: flush, write or read */
		if (do_flush)
			osd_req_flush_object(or, &osdev->obj,
					     OSD_CDB_FLUSH_ALL, 0, 0);
		else if (do_write)
			osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
				      bio, blk_rq_bytes(rq));
		else
			osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
				     bio, blk_rq_bytes(rq));

		OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n",
			do_flush ? "flush" : do_write ?
				"write" : "read", blk_rq_bytes(rq),
			blk_rq_pos(rq) * 512ULL);

		/* begin OSD command execution */
		if (osd_async_op(or, osdblk_osd_complete, orq,
				 osdev->obj_cred)) {
			osd_end_request(or);
			blk_requeue_request(q, rq);
			bio_chain_put(bio);
			OSDBLK_DEBUG("osd_execute_request_async with err\n");
			break;
		}

		/* remove the special 'flush' marker, now that the command
		 * is executing
		 */
		rq->special = NULL;
	}
}

static void osdblk_prepare_flush(struct request_queue *q, struct request *rq)
{
	/* add driver-specific marker, to indicate that this request
	 * is a flush command
	 */
	rq->special = (void *) 0xdeadbeefUL;
}

static void osdblk_free_disk(struct osdblk_device *osdev)
{
	struct gendisk *disk = osdev->disk;

	if (!disk)
		return;

	if (disk->flags & GENHD_FL_UP)
		del_gendisk(disk);
	if (disk->queue)
		blk_cleanup_queue(disk->queue);
	put_disk(disk);
}

static int osdblk_init_disk(struct osdblk_device *osdev)
{
	struct gendisk *disk;
	struct request_queue *q;
	int rc;
	u64 obj_size = 0;

	/* contact OSD, request size info about the object being mapped */
	rc = osdblk_get_obj_size(osdev, &obj_size);
	if (rc)
		return rc;

	/* create gendisk info */
	disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
	if (!disk)
		return -ENOMEM;

	sprintf(disk->disk_name, DRV_NAME "%d", osdev->id);
	disk->major = osdev->major;
	disk->first_minor = 0;
	disk->fops = &osdblk_bd_ops;
	disk->private_data = osdev;

	/* init rq */
	q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
	if (!q) {
		put_disk(disk);
		return -ENOMEM;
	}

	/* switch queue to TCQ mode; allocate tag map */
	rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL);
	if (rc) {
		blk_cleanup_queue(q);
		put_disk(disk);
		return rc;
	}

	/* Set our limits to the lower device limits, because osdblk cannot
	 * sleep when allocating a lower-request and therefore cannot be
	 * bouncing.
	 */
	blk_queue_stack_limits(q, osd_request_queue(osdev->osd));

	blk_queue_prep_rq(q, blk_queue_start_tag);
	blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH, osdblk_prepare_flush);

	disk->queue = q;

	q->queuedata = osdev;

	osdev->disk = disk;
	osdev->q = q;

	/* finally, announce the disk to the world */
	set_capacity(disk, obj_size / 512ULL);
	add_disk(disk);

	printk(KERN_INFO "%s: Added of size 0x%llx\n",
		disk->disk_name, (unsigned long long)obj_size);

	return 0;
}

/********************************************************************
 * /sys/class/osdblk/
 *                   add	map OSD object to blkdev
 *                   remove	unmap OSD object
 *                   list	show mappings
 *******************************************************************/

static void class_osdblk_release(struct class *cls)
{
	kfree(cls);
}

static ssize_t class_osdblk_list(struct class *c,
				struct class_attribute *attr,
				char *data)
{
	int n = 0;
	struct list_head *tmp;

	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

	list_for_each(tmp, &osdblkdev_list) {
		struct osdblk_device *osdev;

		osdev = list_entry(tmp, struct osdblk_device, node);

		n += sprintf(data+n, "%d %d %llu %llu %s\n",
			osdev->id,
			osdev->major,
			osdev->obj.partition,
			osdev->obj.id,
			osdev->osd_path);
	}

	mutex_unlock(&ctl_mutex);
	return n;
}

static ssize_t class_osdblk_add(struct class *c,
				struct class_attribute *attr,
				const char *buf, size_t count)
{
	struct osdblk_device *osdev;
	ssize_t rc;
	int irc, new_id = 0;
	struct list_head *tmp;

	if (!try_module_get(THIS_MODULE))
		return -ENODEV;

	/* new osdblk_device object */
	osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
	if (!osdev) {
		rc = -ENOMEM;
		goto err_out_mod;
	}

	/* static osdblk_device initialization */
	spin_lock_init(&osdev->lock);
	INIT_LIST_HEAD(&osdev->node);

	/* generate unique id: find highest unique id, add one */

	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

	list_for_each(tmp, &osdblkdev_list) {
		struct osdblk_device *osdev;

		osdev = list_entry(tmp, struct osdblk_device, node);
		if (osdev->id > new_id)
			new_id = osdev->id + 1;
	}

	osdev->id = new_id;

	/* add to global list */
	list_add_tail(&osdev->node, &osdblkdev_list);

	mutex_unlock(&ctl_mutex);

	/* parse add command */
	if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,
		   osdev->osd_path) != 3) {
		rc = -EINVAL;
		goto err_out_slot;
	}

	/* initialize rest of new object */
	sprintf(osdev->name, DRV_NAME "%d", osdev->id);

	/* contact requested OSD */
	osdev->osd = osduld_path_lookup(osdev->osd_path);
	if (IS_ERR(osdev->osd)) {
		rc = PTR_ERR(osdev->osd);
		goto err_out_slot;
	}

	/* build OSD credential */
	osdblk_make_credential(osdev->obj_cred, &osdev->obj);

	/* register our block device */
	irc = register_blkdev(0, osdev->name);
	if (irc < 0) {
		rc = irc;
		goto err_out_osd;
	}

	osdev->major = irc;

	/* set up and announce blkdev mapping */
	rc = osdblk_init_disk(osdev);
	if (rc)
		goto err_out_blkdev;

	return count;

err_out_blkdev:
	unregister_blkdev(osdev->major, osdev->name);
err_out_osd:
	osduld_put_device(osdev->osd);
err_out_slot:
	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
	list_del_init(&osdev->node);
	mutex_unlock(&ctl_mutex);

	kfree(osdev);
err_out_mod:
	OSDBLK_DEBUG("Error adding device %s\n", buf);
	module_put(THIS_MODULE);
	return rc;
}

static ssize_t class_osdblk_remove(struct class *c,
					struct class_attribute *attr,
					const char *buf,
					size_t count)
{
	struct osdblk_device *osdev = NULL;
	int target_id, rc;
	unsigned long ul;
	struct list_head *tmp;

	rc = strict_strtoul(buf, 10, &ul);
	if (rc)
		return rc;

	/* convert to int; abort if we lost anything in the conversion */
	target_id = (int) ul;
	if (target_id != ul)
		return -EINVAL;

	/* remove object from list immediately */
	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

	list_for_each(tmp, &osdblkdev_list) {
		osdev = list_entry(tmp, struct osdblk_device, node);
		if (osdev->id == target_id) {
			list_del_init(&osdev->node);
			break;
		}
		osdev = NULL;
	}

	mutex_unlock(&ctl_mutex);

	if (!osdev)
		return -ENOENT;

	/* clean up and free blkdev and associated OSD connection */
	osdblk_free_disk(osdev);
	unregister_blkdev(osdev->major, osdev->name);
	osduld_put_device(osdev->osd);
	kfree(osdev);

	/* release module ref */
	module_put(THIS_MODULE);

	return count;
}

static struct class_attribute class_osdblk_attrs[] = {
	__ATTR(add,	0200, NULL, class_osdblk_add),
	__ATTR(remove,	0200, NULL, class_osdblk_remove),
	__ATTR(list,	0444, class_osdblk_list, NULL),
	__ATTR_NULL
};

static int osdblk_sysfs_init(void)
{
	int ret = 0;

	/*
	 * create control files in sysfs
	 * /sys/class/osdblk/...
	 */
	class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
	if (!class_osdblk)
		return -ENOMEM;

	class_osdblk->name = DRV_NAME;
	class_osdblk->owner = THIS_MODULE;
	class_osdblk->class_release = class_osdblk_release;
	class_osdblk->class_attrs = class_osdblk_attrs;

	ret = class_register(class_osdblk);
	if (ret) {
		kfree(class_osdblk);
		class_osdblk = NULL;
		printk(PFX "failed to create class osdblk\n");
		return ret;
	}

	return 0;
}

static void osdblk_sysfs_cleanup(void)
{
	if (class_osdblk)
		class_destroy(class_osdblk);
	class_osdblk = NULL;
}

static int __init osdblk_init(void)
{
	int rc;

	rc = osdblk_sysfs_init();
	if (rc)
		return rc;

	return 0;
}

static void __exit osdblk_exit(void)
{
	osdblk_sysfs_cleanup();
}

module_init(osdblk_init);
module_exit(osdblk_exit);