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1
2/*
3 osdblk.c -- Export a single SCSI OSD object as a Linux block device
4
5
6 Copyright 2009 Red Hat, Inc.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; see the file COPYING. If not, write to
19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20
21
22 Instructions for use
23 --------------------
24
25 1) Map a Linux block device to an existing OSD object.
26
27 In this example, we will use partition id 1234, object id 5678,
28 OSD device /dev/osd1.
29
30 $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add
31
32
33 2) List all active blkdev<->object mappings.
34
35 In this example, we have performed step #1 twice, creating two blkdevs,
36 mapped to two separate OSD objects.
37
38 $ cat /sys/class/osdblk/list
39 0 174 1234 5678 /dev/osd1
40 1 179 1994 897123 /dev/osd0
41
42 The columns, in order, are:
43 - blkdev unique id
44 - blkdev assigned major
45 - OSD object partition id
46 - OSD object id
47 - OSD device
48
49
50 3) Remove an active blkdev<->object mapping.
51
52 In this example, we remove the mapping with blkdev unique id 1.
53
54 $ echo 1 > /sys/class/osdblk/remove
55
56
57 NOTE: The actual creation and deletion of OSD objects is outside the scope
58 of this driver.
59
60 */
61
62#include <linux/kernel.h>
63#include <linux/device.h>
64#include <linux/module.h>
65#include <linux/fs.h>
66#include <linux/slab.h>
67#include <scsi/osd_initiator.h>
68#include <scsi/osd_attributes.h>
69#include <scsi/osd_sec.h>
70#include <scsi/scsi_device.h>
71
72#define DRV_NAME "osdblk"
73#define PFX DRV_NAME ": "
74
75/* #define _OSDBLK_DEBUG */
76#ifdef _OSDBLK_DEBUG
77#define OSDBLK_DEBUG(fmt, a...) \
78 printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a)
79#else
80#define OSDBLK_DEBUG(fmt, a...) \
81 do { if (0) printk(fmt, ##a); } while (0)
82#endif
83
84MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
85MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
86MODULE_LICENSE("GPL");
87
88struct osdblk_device;
89
90enum {
91 OSDBLK_MINORS_PER_MAJOR = 256, /* max minors per blkdev */
92 OSDBLK_MAX_REQ = 32, /* max parallel requests */
93 OSDBLK_OP_TIMEOUT = 4 * 60, /* sync OSD req timeout */
94};
95
96struct osdblk_request {
97 struct request *rq; /* blk layer request */
98 struct bio *bio; /* cloned bio */
99 struct osdblk_device *osdev; /* associated blkdev */
100};
101
102struct osdblk_device {
103 int id; /* blkdev unique id */
104
105 int major; /* blkdev assigned major */
106 struct gendisk *disk; /* blkdev's gendisk and rq */
107 struct request_queue *q;
108
109 struct osd_dev *osd; /* associated OSD */
110
111 char name[32]; /* blkdev name, e.g. osdblk34 */
112
113 spinlock_t lock; /* queue lock */
114
115 struct osd_obj_id obj; /* OSD partition, obj id */
116 uint8_t obj_cred[OSD_CAP_LEN]; /* OSD cred */
117
118 struct osdblk_request req[OSDBLK_MAX_REQ]; /* request table */
119
120 struct list_head node;
121
122 char osd_path[0]; /* OSD device path */
123};
124
125static struct class *class_osdblk; /* /sys/class/osdblk */
126static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */
127static LIST_HEAD(osdblkdev_list);
128
129static const struct block_device_operations osdblk_bd_ops = {
130 .owner = THIS_MODULE,
131};
132
133static const struct osd_attr g_attr_logical_length = ATTR_DEF(
134 OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
135
136static void osdblk_make_credential(u8 cred_a[OSD_CAP_LEN],
137 const struct osd_obj_id *obj)
138{
139 osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
140}
141
142/* copied from exofs; move to libosd? */
143/*
144 * Perform a synchronous OSD operation. copied from exofs; move to libosd?
145 */
146static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
147{
148 int ret;
149
150 or->timeout = timeout;
151 ret = osd_finalize_request(or, 0, credential, NULL);
152 if (ret)
153 return ret;
154
155 ret = osd_execute_request(or);
156
157 /* osd_req_decode_sense(or, ret); */
158 return ret;
159}
160
161/*
162 * Perform an asynchronous OSD operation. copied from exofs; move to libosd?
163 */
164static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
165 void *caller_context, u8 *cred)
166{
167 int ret;
168
169 ret = osd_finalize_request(or, 0, cred, NULL);
170 if (ret)
171 return ret;
172
173 ret = osd_execute_request_async(or, async_done, caller_context);
174
175 return ret;
176}
177
178/* copied from exofs; move to libosd? */
179static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
180{
181 struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
182 void *iter = NULL;
183 int nelem;
184
185 do {
186 nelem = 1;
187 osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
188 if ((cur_attr.attr_page == attr->attr_page) &&
189 (cur_attr.attr_id == attr->attr_id)) {
190 attr->len = cur_attr.len;
191 attr->val_ptr = cur_attr.val_ptr;
192 return 0;
193 }
194 } while (iter);
195
196 return -EIO;
197}
198
199static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
200{
201 struct osd_request *or;
202 struct osd_attr attr;
203 int ret;
204
205 /* start request */
206 or = osd_start_request(osdev->osd, GFP_KERNEL);
207 if (!or)
208 return -ENOMEM;
209
210 /* create a get-attributes(length) request */
211 osd_req_get_attributes(or, &osdev->obj);
212
213 osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
214
215 /* execute op synchronously */
216 ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
217 if (ret)
218 goto out;
219
220 /* extract length from returned attribute info */
221 attr = g_attr_logical_length;
222 ret = extract_attr_from_req(or, &attr);
223 if (ret)
224 goto out;
225
226 *size_out = get_unaligned_be64(attr.val_ptr);
227
228out:
229 osd_end_request(or);
230 return ret;
231
232}
233
234static void osdblk_osd_complete(struct osd_request *or, void *private)
235{
236 struct osdblk_request *orq = private;
237 struct osd_sense_info osi;
238 int ret = osd_req_decode_sense(or, &osi);
239
240 if (ret) {
241 ret = -EIO;
242 OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret);
243 }
244
245 /* complete OSD request */
246 osd_end_request(or);
247
248 /* complete request passed to osdblk by block layer */
249 __blk_end_request_all(orq->rq, ret);
250}
251
252static void bio_chain_put(struct bio *chain)
253{
254 struct bio *tmp;
255
256 while (chain) {
257 tmp = chain;
258 chain = chain->bi_next;
259
260 bio_put(tmp);
261 }
262}
263
264static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
265{
266 struct bio *tmp, *new_chain = NULL, *tail = NULL;
267
268 while (old_chain) {
269 tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
270 if (!tmp)
271 goto err_out;
272
273 __bio_clone(tmp, old_chain);
274 tmp->bi_bdev = NULL;
275 gfpmask &= ~__GFP_WAIT;
276 tmp->bi_next = NULL;
277
278 if (!new_chain)
279 new_chain = tail = tmp;
280 else {
281 tail->bi_next = tmp;
282 tail = tmp;
283 }
284
285 old_chain = old_chain->bi_next;
286 }
287
288 return new_chain;
289
290err_out:
291 OSDBLK_DEBUG("bio_chain_clone with err\n");
292 bio_chain_put(new_chain);
293 return NULL;
294}
295
296static void osdblk_rq_fn(struct request_queue *q)
297{
298 struct osdblk_device *osdev = q->queuedata;
299
300 while (1) {
301 struct request *rq;
302 struct osdblk_request *orq;
303 struct osd_request *or;
304 struct bio *bio;
305 bool do_write, do_flush;
306
307 /* peek at request from block layer */
308 rq = blk_fetch_request(q);
309 if (!rq)
310 break;
311
312 /* filter out block requests we don't understand */
313 if (rq->cmd_type != REQ_TYPE_FS) {
314 blk_end_request_all(rq, 0);
315 continue;
316 }
317
318 /* deduce our operation (read, write, flush) */
319 /* I wish the block layer simplified cmd_type/cmd_flags/cmd[]
320 * into a clearly defined set of RPC commands:
321 * read, write, flush, scsi command, power mgmt req,
322 * driver-specific, etc.
323 */
324
325 do_flush = rq->cmd_flags & REQ_FLUSH;
326 do_write = (rq_data_dir(rq) == WRITE);
327
328 if (!do_flush) { /* osd_flush does not use a bio */
329 /* a bio clone to be passed down to OSD request */
330 bio = bio_chain_clone(rq->bio, GFP_ATOMIC);
331 if (!bio)
332 break;
333 } else
334 bio = NULL;
335
336 /* alloc internal OSD request, for OSD command execution */
337 or = osd_start_request(osdev->osd, GFP_ATOMIC);
338 if (!or) {
339 bio_chain_put(bio);
340 OSDBLK_DEBUG("osd_start_request with err\n");
341 break;
342 }
343
344 orq = &osdev->req[rq->tag];
345 orq->rq = rq;
346 orq->bio = bio;
347 orq->osdev = osdev;
348
349 /* init OSD command: flush, write or read */
350 if (do_flush)
351 osd_req_flush_object(or, &osdev->obj,
352 OSD_CDB_FLUSH_ALL, 0, 0);
353 else if (do_write)
354 osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
355 bio, blk_rq_bytes(rq));
356 else
357 osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
358 bio, blk_rq_bytes(rq));
359
360 OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n",
361 do_flush ? "flush" : do_write ?
362 "write" : "read", blk_rq_bytes(rq),
363 blk_rq_pos(rq) * 512ULL);
364
365 /* begin OSD command execution */
366 if (osd_async_op(or, osdblk_osd_complete, orq,
367 osdev->obj_cred)) {
368 osd_end_request(or);
369 blk_requeue_request(q, rq);
370 bio_chain_put(bio);
371 OSDBLK_DEBUG("osd_execute_request_async with err\n");
372 break;
373 }
374
375 /* remove the special 'flush' marker, now that the command
376 * is executing
377 */
378 rq->special = NULL;
379 }
380}
381
382static void osdblk_free_disk(struct osdblk_device *osdev)
383{
384 struct gendisk *disk = osdev->disk;
385
386 if (!disk)
387 return;
388
389 if (disk->flags & GENHD_FL_UP)
390 del_gendisk(disk);
391 if (disk->queue)
392 blk_cleanup_queue(disk->queue);
393 put_disk(disk);
394}
395
396static int osdblk_init_disk(struct osdblk_device *osdev)
397{
398 struct gendisk *disk;
399 struct request_queue *q;
400 int rc;
401 u64 obj_size = 0;
402
403 /* contact OSD, request size info about the object being mapped */
404 rc = osdblk_get_obj_size(osdev, &obj_size);
405 if (rc)
406 return rc;
407
408 /* create gendisk info */
409 disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
410 if (!disk)
411 return -ENOMEM;
412
413 sprintf(disk->disk_name, DRV_NAME "%d", osdev->id);
414 disk->major = osdev->major;
415 disk->first_minor = 0;
416 disk->fops = &osdblk_bd_ops;
417 disk->private_data = osdev;
418
419 /* init rq */
420 q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
421 if (!q) {
422 put_disk(disk);
423 return -ENOMEM;
424 }
425
426 /* switch queue to TCQ mode; allocate tag map */
427 rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL);
428 if (rc) {
429 blk_cleanup_queue(q);
430 put_disk(disk);
431 return rc;
432 }
433
434 /* Set our limits to the lower device limits, because osdblk cannot
435 * sleep when allocating a lower-request and therefore cannot be
436 * bouncing.
437 */
438 blk_queue_stack_limits(q, osd_request_queue(osdev->osd));
439
440 blk_queue_prep_rq(q, blk_queue_start_tag);
441 blk_queue_flush(q, REQ_FLUSH);
442
443 disk->queue = q;
444
445 q->queuedata = osdev;
446
447 osdev->disk = disk;
448 osdev->q = q;
449
450 /* finally, announce the disk to the world */
451 set_capacity(disk, obj_size / 512ULL);
452 add_disk(disk);
453
454 printk(KERN_INFO "%s: Added of size 0x%llx\n",
455 disk->disk_name, (unsigned long long)obj_size);
456
457 return 0;
458}
459
460/********************************************************************
461 * /sys/class/osdblk/
462 * add map OSD object to blkdev
463 * remove unmap OSD object
464 * list show mappings
465 *******************************************************************/
466
467static void class_osdblk_release(struct class *cls)
468{
469 kfree(cls);
470}
471
472static ssize_t class_osdblk_list(struct class *c,
473 struct class_attribute *attr,
474 char *data)
475{
476 int n = 0;
477 struct list_head *tmp;
478
479 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
480
481 list_for_each(tmp, &osdblkdev_list) {
482 struct osdblk_device *osdev;
483
484 osdev = list_entry(tmp, struct osdblk_device, node);
485
486 n += sprintf(data+n, "%d %d %llu %llu %s\n",
487 osdev->id,
488 osdev->major,
489 osdev->obj.partition,
490 osdev->obj.id,
491 osdev->osd_path);
492 }
493
494 mutex_unlock(&ctl_mutex);
495 return n;
496}
497
498static ssize_t class_osdblk_add(struct class *c,
499 struct class_attribute *attr,
500 const char *buf, size_t count)
501{
502 struct osdblk_device *osdev;
503 ssize_t rc;
504 int irc, new_id = 0;
505 struct list_head *tmp;
506
507 if (!try_module_get(THIS_MODULE))
508 return -ENODEV;
509
510 /* new osdblk_device object */
511 osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
512 if (!osdev) {
513 rc = -ENOMEM;
514 goto err_out_mod;
515 }
516
517 /* static osdblk_device initialization */
518 spin_lock_init(&osdev->lock);
519 INIT_LIST_HEAD(&osdev->node);
520
521 /* generate unique id: find highest unique id, add one */
522
523 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
524
525 list_for_each(tmp, &osdblkdev_list) {
526 struct osdblk_device *osdev;
527
528 osdev = list_entry(tmp, struct osdblk_device, node);
529 if (osdev->id > new_id)
530 new_id = osdev->id + 1;
531 }
532
533 osdev->id = new_id;
534
535 /* add to global list */
536 list_add_tail(&osdev->node, &osdblkdev_list);
537
538 mutex_unlock(&ctl_mutex);
539
540 /* parse add command */
541 if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,
542 osdev->osd_path) != 3) {
543 rc = -EINVAL;
544 goto err_out_slot;
545 }
546
547 /* initialize rest of new object */
548 sprintf(osdev->name, DRV_NAME "%d", osdev->id);
549
550 /* contact requested OSD */
551 osdev->osd = osduld_path_lookup(osdev->osd_path);
552 if (IS_ERR(osdev->osd)) {
553 rc = PTR_ERR(osdev->osd);
554 goto err_out_slot;
555 }
556
557 /* build OSD credential */
558 osdblk_make_credential(osdev->obj_cred, &osdev->obj);
559
560 /* register our block device */
561 irc = register_blkdev(0, osdev->name);
562 if (irc < 0) {
563 rc = irc;
564 goto err_out_osd;
565 }
566
567 osdev->major = irc;
568
569 /* set up and announce blkdev mapping */
570 rc = osdblk_init_disk(osdev);
571 if (rc)
572 goto err_out_blkdev;
573
574 return count;
575
576err_out_blkdev:
577 unregister_blkdev(osdev->major, osdev->name);
578err_out_osd:
579 osduld_put_device(osdev->osd);
580err_out_slot:
581 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
582 list_del_init(&osdev->node);
583 mutex_unlock(&ctl_mutex);
584
585 kfree(osdev);
586err_out_mod:
587 OSDBLK_DEBUG("Error adding device %s\n", buf);
588 module_put(THIS_MODULE);
589 return rc;
590}
591
592static ssize_t class_osdblk_remove(struct class *c,
593 struct class_attribute *attr,
594 const char *buf,
595 size_t count)
596{
597 struct osdblk_device *osdev = NULL;
598 int target_id, rc;
599 unsigned long ul;
600 struct list_head *tmp;
601
602 rc = strict_strtoul(buf, 10, &ul);
603 if (rc)
604 return rc;
605
606 /* convert to int; abort if we lost anything in the conversion */
607 target_id = (int) ul;
608 if (target_id != ul)
609 return -EINVAL;
610
611 /* remove object from list immediately */
612 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
613
614 list_for_each(tmp, &osdblkdev_list) {
615 osdev = list_entry(tmp, struct osdblk_device, node);
616 if (osdev->id == target_id) {
617 list_del_init(&osdev->node);
618 break;
619 }
620 osdev = NULL;
621 }
622
623 mutex_unlock(&ctl_mutex);
624
625 if (!osdev)
626 return -ENOENT;
627
628 /* clean up and free blkdev and associated OSD connection */
629 osdblk_free_disk(osdev);
630 unregister_blkdev(osdev->major, osdev->name);
631 osduld_put_device(osdev->osd);
632 kfree(osdev);
633
634 /* release module ref */
635 module_put(THIS_MODULE);
636
637 return count;
638}
639
640static struct class_attribute class_osdblk_attrs[] = {
641 __ATTR(add, 0200, NULL, class_osdblk_add),
642 __ATTR(remove, 0200, NULL, class_osdblk_remove),
643 __ATTR(list, 0444, class_osdblk_list, NULL),
644 __ATTR_NULL
645};
646
647static int osdblk_sysfs_init(void)
648{
649 int ret = 0;
650
651 /*
652 * create control files in sysfs
653 * /sys/class/osdblk/...
654 */
655 class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
656 if (!class_osdblk)
657 return -ENOMEM;
658
659 class_osdblk->name = DRV_NAME;
660 class_osdblk->owner = THIS_MODULE;
661 class_osdblk->class_release = class_osdblk_release;
662 class_osdblk->class_attrs = class_osdblk_attrs;
663
664 ret = class_register(class_osdblk);
665 if (ret) {
666 kfree(class_osdblk);
667 class_osdblk = NULL;
668 printk(PFX "failed to create class osdblk\n");
669 return ret;
670 }
671
672 return 0;
673}
674
675static void osdblk_sysfs_cleanup(void)
676{
677 if (class_osdblk)
678 class_destroy(class_osdblk);
679 class_osdblk = NULL;
680}
681
682static int __init osdblk_init(void)
683{
684 int rc;
685
686 rc = osdblk_sysfs_init();
687 if (rc)
688 return rc;
689
690 return 0;
691}
692
693static void __exit osdblk_exit(void)
694{
695 osdblk_sysfs_cleanup();
696}
697
698module_init(osdblk_init);
699module_exit(osdblk_exit);
700