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
84 MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
85 MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
86 MODULE_LICENSE("GPL");
87
88 struct osdblk_device;
89
90 enum {
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
96 struct osdblk_request {
97 struct request *rq; /* blk layer request */
98 struct bio *bio; /* cloned bio */
99 struct osdblk_device *osdev; /* associated blkdev */
100 };
101
102 struct 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
125 static struct class *class_osdblk; /* /sys/class/osdblk */
126 static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */
127 static LIST_HEAD(osdblkdev_list);
128
129 static const struct block_device_operations osdblk_bd_ops = {
130 .owner = THIS_MODULE,
131 };
132
133 static const struct osd_attr g_attr_logical_length = ATTR_DEF(
134 OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
135
osdblk_make_credential(u8 cred_a[OSD_CAP_LEN],const struct osd_obj_id * obj)136 static 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 */
osd_sync_op(struct osd_request * or,int timeout,uint8_t * credential)146 static 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 */
osd_async_op(struct osd_request * or,osd_req_done_fn * async_done,void * caller_context,u8 * cred)164 static 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? */
extract_attr_from_req(struct osd_request * or,struct osd_attr * attr)179 static 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
osdblk_get_obj_size(struct osdblk_device * osdev,u64 * size_out)199 static 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
228 out:
229 osd_end_request(or);
230 return ret;
231
232 }
233
osdblk_osd_complete(struct osd_request * or,void * private)234 static 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
bio_chain_put(struct bio * chain)252 static 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
bio_chain_clone(struct bio * old_chain,gfp_t gfpmask)264 static 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_clone_kmalloc(old_chain, gfpmask);
270 if (!tmp)
271 goto err_out;
272
273 tmp->bi_bdev = NULL;
274 gfpmask &= ~__GFP_WAIT;
275 tmp->bi_next = NULL;
276
277 if (!new_chain)
278 new_chain = tail = tmp;
279 else {
280 tail->bi_next = tmp;
281 tail = tmp;
282 }
283
284 old_chain = old_chain->bi_next;
285 }
286
287 return new_chain;
288
289 err_out:
290 OSDBLK_DEBUG("bio_chain_clone with err\n");
291 bio_chain_put(new_chain);
292 return NULL;
293 }
294
osdblk_rq_fn(struct request_queue * q)295 static void osdblk_rq_fn(struct request_queue *q)
296 {
297 struct osdblk_device *osdev = q->queuedata;
298
299 while (1) {
300 struct request *rq;
301 struct osdblk_request *orq;
302 struct osd_request *or;
303 struct bio *bio;
304 bool do_write, do_flush;
305
306 /* peek at request from block layer */
307 rq = blk_fetch_request(q);
308 if (!rq)
309 break;
310
311 /* filter out block requests we don't understand */
312 if (rq->cmd_type != REQ_TYPE_FS) {
313 blk_end_request_all(rq, 0);
314 continue;
315 }
316
317 /* deduce our operation (read, write, flush) */
318 /* I wish the block layer simplified cmd_type/cmd_flags/cmd[]
319 * into a clearly defined set of RPC commands:
320 * read, write, flush, scsi command, power mgmt req,
321 * driver-specific, etc.
322 */
323
324 do_flush = rq->cmd_flags & REQ_FLUSH;
325 do_write = (rq_data_dir(rq) == WRITE);
326
327 if (!do_flush) { /* osd_flush does not use a bio */
328 /* a bio clone to be passed down to OSD request */
329 bio = bio_chain_clone(rq->bio, GFP_ATOMIC);
330 if (!bio)
331 break;
332 } else
333 bio = NULL;
334
335 /* alloc internal OSD request, for OSD command execution */
336 or = osd_start_request(osdev->osd, GFP_ATOMIC);
337 if (!or) {
338 bio_chain_put(bio);
339 OSDBLK_DEBUG("osd_start_request with err\n");
340 break;
341 }
342
343 orq = &osdev->req[rq->tag];
344 orq->rq = rq;
345 orq->bio = bio;
346 orq->osdev = osdev;
347
348 /* init OSD command: flush, write or read */
349 if (do_flush)
350 osd_req_flush_object(or, &osdev->obj,
351 OSD_CDB_FLUSH_ALL, 0, 0);
352 else if (do_write)
353 osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
354 bio, blk_rq_bytes(rq));
355 else
356 osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
357 bio, blk_rq_bytes(rq));
358
359 OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n",
360 do_flush ? "flush" : do_write ?
361 "write" : "read", blk_rq_bytes(rq),
362 blk_rq_pos(rq) * 512ULL);
363
364 /* begin OSD command execution */
365 if (osd_async_op(or, osdblk_osd_complete, orq,
366 osdev->obj_cred)) {
367 osd_end_request(or);
368 blk_requeue_request(q, rq);
369 bio_chain_put(bio);
370 OSDBLK_DEBUG("osd_execute_request_async with err\n");
371 break;
372 }
373
374 /* remove the special 'flush' marker, now that the command
375 * is executing
376 */
377 rq->special = NULL;
378 }
379 }
380
osdblk_free_disk(struct osdblk_device * osdev)381 static void osdblk_free_disk(struct osdblk_device *osdev)
382 {
383 struct gendisk *disk = osdev->disk;
384
385 if (!disk)
386 return;
387
388 if (disk->flags & GENHD_FL_UP)
389 del_gendisk(disk);
390 if (disk->queue)
391 blk_cleanup_queue(disk->queue);
392 put_disk(disk);
393 }
394
osdblk_init_disk(struct osdblk_device * osdev)395 static int osdblk_init_disk(struct osdblk_device *osdev)
396 {
397 struct gendisk *disk;
398 struct request_queue *q;
399 int rc;
400 u64 obj_size = 0;
401
402 /* contact OSD, request size info about the object being mapped */
403 rc = osdblk_get_obj_size(osdev, &obj_size);
404 if (rc)
405 return rc;
406
407 /* create gendisk info */
408 disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
409 if (!disk)
410 return -ENOMEM;
411
412 sprintf(disk->disk_name, DRV_NAME "%d", osdev->id);
413 disk->major = osdev->major;
414 disk->first_minor = 0;
415 disk->fops = &osdblk_bd_ops;
416 disk->private_data = osdev;
417
418 /* init rq */
419 q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
420 if (!q) {
421 put_disk(disk);
422 return -ENOMEM;
423 }
424
425 /* switch queue to TCQ mode; allocate tag map */
426 rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL);
427 if (rc) {
428 blk_cleanup_queue(q);
429 put_disk(disk);
430 return rc;
431 }
432
433 /* Set our limits to the lower device limits, because osdblk cannot
434 * sleep when allocating a lower-request and therefore cannot be
435 * bouncing.
436 */
437 blk_queue_stack_limits(q, osd_request_queue(osdev->osd));
438
439 blk_queue_prep_rq(q, blk_queue_start_tag);
440 blk_queue_flush(q, REQ_FLUSH);
441
442 disk->queue = q;
443
444 q->queuedata = osdev;
445
446 osdev->disk = disk;
447 osdev->q = q;
448
449 /* finally, announce the disk to the world */
450 set_capacity(disk, obj_size / 512ULL);
451 add_disk(disk);
452
453 printk(KERN_INFO "%s: Added of size 0x%llx\n",
454 disk->disk_name, (unsigned long long)obj_size);
455
456 return 0;
457 }
458
459 /********************************************************************
460 * /sys/class/osdblk/
461 * add map OSD object to blkdev
462 * remove unmap OSD object
463 * list show mappings
464 *******************************************************************/
465
class_osdblk_release(struct class * cls)466 static void class_osdblk_release(struct class *cls)
467 {
468 kfree(cls);
469 }
470
class_osdblk_list(struct class * c,struct class_attribute * attr,char * data)471 static ssize_t class_osdblk_list(struct class *c,
472 struct class_attribute *attr,
473 char *data)
474 {
475 int n = 0;
476 struct list_head *tmp;
477
478 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
479
480 list_for_each(tmp, &osdblkdev_list) {
481 struct osdblk_device *osdev;
482
483 osdev = list_entry(tmp, struct osdblk_device, node);
484
485 n += sprintf(data+n, "%d %d %llu %llu %s\n",
486 osdev->id,
487 osdev->major,
488 osdev->obj.partition,
489 osdev->obj.id,
490 osdev->osd_path);
491 }
492
493 mutex_unlock(&ctl_mutex);
494 return n;
495 }
496
class_osdblk_add(struct class * c,struct class_attribute * attr,const char * buf,size_t count)497 static ssize_t class_osdblk_add(struct class *c,
498 struct class_attribute *attr,
499 const char *buf, size_t count)
500 {
501 struct osdblk_device *osdev;
502 ssize_t rc;
503 int irc, new_id = 0;
504 struct list_head *tmp;
505
506 if (!try_module_get(THIS_MODULE))
507 return -ENODEV;
508
509 /* new osdblk_device object */
510 osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
511 if (!osdev) {
512 rc = -ENOMEM;
513 goto err_out_mod;
514 }
515
516 /* static osdblk_device initialization */
517 spin_lock_init(&osdev->lock);
518 INIT_LIST_HEAD(&osdev->node);
519
520 /* generate unique id: find highest unique id, add one */
521
522 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
523
524 list_for_each(tmp, &osdblkdev_list) {
525 struct osdblk_device *osdev;
526
527 osdev = list_entry(tmp, struct osdblk_device, node);
528 if (osdev->id > new_id)
529 new_id = osdev->id + 1;
530 }
531
532 osdev->id = new_id;
533
534 /* add to global list */
535 list_add_tail(&osdev->node, &osdblkdev_list);
536
537 mutex_unlock(&ctl_mutex);
538
539 /* parse add command */
540 if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,
541 osdev->osd_path) != 3) {
542 rc = -EINVAL;
543 goto err_out_slot;
544 }
545
546 /* initialize rest of new object */
547 sprintf(osdev->name, DRV_NAME "%d", osdev->id);
548
549 /* contact requested OSD */
550 osdev->osd = osduld_path_lookup(osdev->osd_path);
551 if (IS_ERR(osdev->osd)) {
552 rc = PTR_ERR(osdev->osd);
553 goto err_out_slot;
554 }
555
556 /* build OSD credential */
557 osdblk_make_credential(osdev->obj_cred, &osdev->obj);
558
559 /* register our block device */
560 irc = register_blkdev(0, osdev->name);
561 if (irc < 0) {
562 rc = irc;
563 goto err_out_osd;
564 }
565
566 osdev->major = irc;
567
568 /* set up and announce blkdev mapping */
569 rc = osdblk_init_disk(osdev);
570 if (rc)
571 goto err_out_blkdev;
572
573 return count;
574
575 err_out_blkdev:
576 unregister_blkdev(osdev->major, osdev->name);
577 err_out_osd:
578 osduld_put_device(osdev->osd);
579 err_out_slot:
580 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
581 list_del_init(&osdev->node);
582 mutex_unlock(&ctl_mutex);
583
584 kfree(osdev);
585 err_out_mod:
586 OSDBLK_DEBUG("Error adding device %s\n", buf);
587 module_put(THIS_MODULE);
588 return rc;
589 }
590
class_osdblk_remove(struct class * c,struct class_attribute * attr,const char * buf,size_t count)591 static ssize_t class_osdblk_remove(struct class *c,
592 struct class_attribute *attr,
593 const char *buf,
594 size_t count)
595 {
596 struct osdblk_device *osdev = NULL;
597 int target_id, rc;
598 unsigned long ul;
599 struct list_head *tmp;
600
601 rc = strict_strtoul(buf, 10, &ul);
602 if (rc)
603 return rc;
604
605 /* convert to int; abort if we lost anything in the conversion */
606 target_id = (int) ul;
607 if (target_id != ul)
608 return -EINVAL;
609
610 /* remove object from list immediately */
611 mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
612
613 list_for_each(tmp, &osdblkdev_list) {
614 osdev = list_entry(tmp, struct osdblk_device, node);
615 if (osdev->id == target_id) {
616 list_del_init(&osdev->node);
617 break;
618 }
619 osdev = NULL;
620 }
621
622 mutex_unlock(&ctl_mutex);
623
624 if (!osdev)
625 return -ENOENT;
626
627 /* clean up and free blkdev and associated OSD connection */
628 osdblk_free_disk(osdev);
629 unregister_blkdev(osdev->major, osdev->name);
630 osduld_put_device(osdev->osd);
631 kfree(osdev);
632
633 /* release module ref */
634 module_put(THIS_MODULE);
635
636 return count;
637 }
638
639 static struct class_attribute class_osdblk_attrs[] = {
640 __ATTR(add, 0200, NULL, class_osdblk_add),
641 __ATTR(remove, 0200, NULL, class_osdblk_remove),
642 __ATTR(list, 0444, class_osdblk_list, NULL),
643 __ATTR_NULL
644 };
645
osdblk_sysfs_init(void)646 static int osdblk_sysfs_init(void)
647 {
648 int ret = 0;
649
650 /*
651 * create control files in sysfs
652 * /sys/class/osdblk/...
653 */
654 class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
655 if (!class_osdblk)
656 return -ENOMEM;
657
658 class_osdblk->name = DRV_NAME;
659 class_osdblk->owner = THIS_MODULE;
660 class_osdblk->class_release = class_osdblk_release;
661 class_osdblk->class_attrs = class_osdblk_attrs;
662
663 ret = class_register(class_osdblk);
664 if (ret) {
665 kfree(class_osdblk);
666 class_osdblk = NULL;
667 printk(PFX "failed to create class osdblk\n");
668 return ret;
669 }
670
671 return 0;
672 }
673
osdblk_sysfs_cleanup(void)674 static void osdblk_sysfs_cleanup(void)
675 {
676 if (class_osdblk)
677 class_destroy(class_osdblk);
678 class_osdblk = NULL;
679 }
680
osdblk_init(void)681 static int __init osdblk_init(void)
682 {
683 int rc;
684
685 rc = osdblk_sysfs_init();
686 if (rc)
687 return rc;
688
689 return 0;
690 }
691
osdblk_exit(void)692 static void __exit osdblk_exit(void)
693 {
694 osdblk_sysfs_cleanup();
695 }
696
697 module_init(osdblk_init);
698 module_exit(osdblk_exit);
699
700