xref: /openbmc/linux/drivers/md/md-cluster.c (revision 4f205687)
1 /*
2  * Copyright (C) 2015, SUSE
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2, or (at your option)
7  * any later version.
8  *
9  */
10 
11 
12 #include <linux/module.h>
13 #include <linux/dlm.h>
14 #include <linux/sched.h>
15 #include <linux/raid/md_p.h>
16 #include "md.h"
17 #include "bitmap.h"
18 #include "md-cluster.h"
19 
20 #define LVB_SIZE	64
21 #define NEW_DEV_TIMEOUT 5000
22 
23 struct dlm_lock_resource {
24 	dlm_lockspace_t *ls;
25 	struct dlm_lksb lksb;
26 	char *name; /* lock name. */
27 	uint32_t flags; /* flags to pass to dlm_lock() */
28 	struct completion completion; /* completion for synchronized locking */
29 	void (*bast)(void *arg, int mode); /* blocking AST function pointer*/
30 	struct mddev *mddev; /* pointing back to mddev. */
31 	int mode;
32 };
33 
34 struct suspend_info {
35 	int slot;
36 	sector_t lo;
37 	sector_t hi;
38 	struct list_head list;
39 };
40 
41 struct resync_info {
42 	__le64 lo;
43 	__le64 hi;
44 };
45 
46 /* md_cluster_info flags */
47 #define		MD_CLUSTER_WAITING_FOR_NEWDISK		1
48 #define		MD_CLUSTER_SUSPEND_READ_BALANCING	2
49 #define		MD_CLUSTER_BEGIN_JOIN_CLUSTER		3
50 
51 /* Lock the send communication. This is done through
52  * bit manipulation as opposed to a mutex in order to
53  * accomodate lock and hold. See next comment.
54  */
55 #define		MD_CLUSTER_SEND_LOCK			4
56 /* If cluster operations (such as adding a disk) must lock the
57  * communication channel, so as to perform extra operations
58  * (update metadata) and no other operation is allowed on the
59  * MD. Token needs to be locked and held until the operation
60  * completes witha md_update_sb(), which would eventually release
61  * the lock.
62  */
63 #define		MD_CLUSTER_SEND_LOCKED_ALREADY		5
64 /* We should receive message after node joined cluster and
65  * set up all the related infos such as bitmap and personality */
66 #define		MD_CLUSTER_ALREADY_IN_CLUSTER		6
67 #define		MD_CLUSTER_PENDING_RECV_EVENT		7
68 
69 
70 struct md_cluster_info {
71 	/* dlm lock space and resources for clustered raid. */
72 	dlm_lockspace_t *lockspace;
73 	int slot_number;
74 	struct completion completion;
75 	struct mutex recv_mutex;
76 	struct dlm_lock_resource *bitmap_lockres;
77 	struct dlm_lock_resource **other_bitmap_lockres;
78 	struct dlm_lock_resource *resync_lockres;
79 	struct list_head suspend_list;
80 	spinlock_t suspend_lock;
81 	struct md_thread *recovery_thread;
82 	unsigned long recovery_map;
83 	/* communication loc resources */
84 	struct dlm_lock_resource *ack_lockres;
85 	struct dlm_lock_resource *message_lockres;
86 	struct dlm_lock_resource *token_lockres;
87 	struct dlm_lock_resource *no_new_dev_lockres;
88 	struct md_thread *recv_thread;
89 	struct completion newdisk_completion;
90 	wait_queue_head_t wait;
91 	unsigned long state;
92 	/* record the region in RESYNCING message */
93 	sector_t sync_low;
94 	sector_t sync_hi;
95 };
96 
97 enum msg_type {
98 	METADATA_UPDATED = 0,
99 	RESYNCING,
100 	NEWDISK,
101 	REMOVE,
102 	RE_ADD,
103 	BITMAP_NEEDS_SYNC,
104 };
105 
106 struct cluster_msg {
107 	__le32 type;
108 	__le32 slot;
109 	/* TODO: Unionize this for smaller footprint */
110 	__le64 low;
111 	__le64 high;
112 	char uuid[16];
113 	__le32 raid_slot;
114 };
115 
116 static void sync_ast(void *arg)
117 {
118 	struct dlm_lock_resource *res;
119 
120 	res = arg;
121 	complete(&res->completion);
122 }
123 
124 static int dlm_lock_sync(struct dlm_lock_resource *res, int mode)
125 {
126 	int ret = 0;
127 
128 	ret = dlm_lock(res->ls, mode, &res->lksb,
129 			res->flags, res->name, strlen(res->name),
130 			0, sync_ast, res, res->bast);
131 	if (ret)
132 		return ret;
133 	wait_for_completion(&res->completion);
134 	if (res->lksb.sb_status == 0)
135 		res->mode = mode;
136 	return res->lksb.sb_status;
137 }
138 
139 static int dlm_unlock_sync(struct dlm_lock_resource *res)
140 {
141 	return dlm_lock_sync(res, DLM_LOCK_NL);
142 }
143 
144 static struct dlm_lock_resource *lockres_init(struct mddev *mddev,
145 		char *name, void (*bastfn)(void *arg, int mode), int with_lvb)
146 {
147 	struct dlm_lock_resource *res = NULL;
148 	int ret, namelen;
149 	struct md_cluster_info *cinfo = mddev->cluster_info;
150 
151 	res = kzalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
152 	if (!res)
153 		return NULL;
154 	init_completion(&res->completion);
155 	res->ls = cinfo->lockspace;
156 	res->mddev = mddev;
157 	res->mode = DLM_LOCK_IV;
158 	namelen = strlen(name);
159 	res->name = kzalloc(namelen + 1, GFP_KERNEL);
160 	if (!res->name) {
161 		pr_err("md-cluster: Unable to allocate resource name for resource %s\n", name);
162 		goto out_err;
163 	}
164 	strlcpy(res->name, name, namelen + 1);
165 	if (with_lvb) {
166 		res->lksb.sb_lvbptr = kzalloc(LVB_SIZE, GFP_KERNEL);
167 		if (!res->lksb.sb_lvbptr) {
168 			pr_err("md-cluster: Unable to allocate LVB for resource %s\n", name);
169 			goto out_err;
170 		}
171 		res->flags = DLM_LKF_VALBLK;
172 	}
173 
174 	if (bastfn)
175 		res->bast = bastfn;
176 
177 	res->flags |= DLM_LKF_EXPEDITE;
178 
179 	ret = dlm_lock_sync(res, DLM_LOCK_NL);
180 	if (ret) {
181 		pr_err("md-cluster: Unable to lock NL on new lock resource %s\n", name);
182 		goto out_err;
183 	}
184 	res->flags &= ~DLM_LKF_EXPEDITE;
185 	res->flags |= DLM_LKF_CONVERT;
186 
187 	return res;
188 out_err:
189 	kfree(res->lksb.sb_lvbptr);
190 	kfree(res->name);
191 	kfree(res);
192 	return NULL;
193 }
194 
195 static void lockres_free(struct dlm_lock_resource *res)
196 {
197 	int ret;
198 
199 	if (!res)
200 		return;
201 
202 	/* cancel a lock request or a conversion request that is blocked */
203 	res->flags |= DLM_LKF_CANCEL;
204 retry:
205 	ret = dlm_unlock(res->ls, res->lksb.sb_lkid, 0, &res->lksb, res);
206 	if (unlikely(ret != 0)) {
207 		pr_info("%s: failed to unlock %s return %d\n", __func__, res->name, ret);
208 
209 		/* if a lock conversion is cancelled, then the lock is put
210 		 * back to grant queue, need to ensure it is unlocked */
211 		if (ret == -DLM_ECANCEL)
212 			goto retry;
213 	}
214 	res->flags &= ~DLM_LKF_CANCEL;
215 	wait_for_completion(&res->completion);
216 
217 	kfree(res->name);
218 	kfree(res->lksb.sb_lvbptr);
219 	kfree(res);
220 }
221 
222 static void add_resync_info(struct dlm_lock_resource *lockres,
223 			    sector_t lo, sector_t hi)
224 {
225 	struct resync_info *ri;
226 
227 	ri = (struct resync_info *)lockres->lksb.sb_lvbptr;
228 	ri->lo = cpu_to_le64(lo);
229 	ri->hi = cpu_to_le64(hi);
230 }
231 
232 static struct suspend_info *read_resync_info(struct mddev *mddev, struct dlm_lock_resource *lockres)
233 {
234 	struct resync_info ri;
235 	struct suspend_info *s = NULL;
236 	sector_t hi = 0;
237 
238 	dlm_lock_sync(lockres, DLM_LOCK_CR);
239 	memcpy(&ri, lockres->lksb.sb_lvbptr, sizeof(struct resync_info));
240 	hi = le64_to_cpu(ri.hi);
241 	if (hi > 0) {
242 		s = kzalloc(sizeof(struct suspend_info), GFP_KERNEL);
243 		if (!s)
244 			goto out;
245 		s->hi = hi;
246 		s->lo = le64_to_cpu(ri.lo);
247 	}
248 	dlm_unlock_sync(lockres);
249 out:
250 	return s;
251 }
252 
253 static void recover_bitmaps(struct md_thread *thread)
254 {
255 	struct mddev *mddev = thread->mddev;
256 	struct md_cluster_info *cinfo = mddev->cluster_info;
257 	struct dlm_lock_resource *bm_lockres;
258 	char str[64];
259 	int slot, ret;
260 	struct suspend_info *s, *tmp;
261 	sector_t lo, hi;
262 
263 	while (cinfo->recovery_map) {
264 		slot = fls64((u64)cinfo->recovery_map) - 1;
265 
266 		/* Clear suspend_area associated with the bitmap */
267 		spin_lock_irq(&cinfo->suspend_lock);
268 		list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
269 			if (slot == s->slot) {
270 				list_del(&s->list);
271 				kfree(s);
272 			}
273 		spin_unlock_irq(&cinfo->suspend_lock);
274 
275 		snprintf(str, 64, "bitmap%04d", slot);
276 		bm_lockres = lockres_init(mddev, str, NULL, 1);
277 		if (!bm_lockres) {
278 			pr_err("md-cluster: Cannot initialize bitmaps\n");
279 			goto clear_bit;
280 		}
281 
282 		ret = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
283 		if (ret) {
284 			pr_err("md-cluster: Could not DLM lock %s: %d\n",
285 					str, ret);
286 			goto clear_bit;
287 		}
288 		ret = bitmap_copy_from_slot(mddev, slot, &lo, &hi, true);
289 		if (ret) {
290 			pr_err("md-cluster: Could not copy data from bitmap %d\n", slot);
291 			goto dlm_unlock;
292 		}
293 		if (hi > 0) {
294 			if (lo < mddev->recovery_cp)
295 				mddev->recovery_cp = lo;
296 			/* wake up thread to continue resync in case resync
297 			 * is not finished */
298 			if (mddev->recovery_cp != MaxSector) {
299 			    set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
300 			    md_wakeup_thread(mddev->thread);
301 			}
302 		}
303 dlm_unlock:
304 		dlm_unlock_sync(bm_lockres);
305 clear_bit:
306 		lockres_free(bm_lockres);
307 		clear_bit(slot, &cinfo->recovery_map);
308 	}
309 }
310 
311 static void recover_prep(void *arg)
312 {
313 	struct mddev *mddev = arg;
314 	struct md_cluster_info *cinfo = mddev->cluster_info;
315 	set_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state);
316 }
317 
318 static void __recover_slot(struct mddev *mddev, int slot)
319 {
320 	struct md_cluster_info *cinfo = mddev->cluster_info;
321 
322 	set_bit(slot, &cinfo->recovery_map);
323 	if (!cinfo->recovery_thread) {
324 		cinfo->recovery_thread = md_register_thread(recover_bitmaps,
325 				mddev, "recover");
326 		if (!cinfo->recovery_thread) {
327 			pr_warn("md-cluster: Could not create recovery thread\n");
328 			return;
329 		}
330 	}
331 	md_wakeup_thread(cinfo->recovery_thread);
332 }
333 
334 static void recover_slot(void *arg, struct dlm_slot *slot)
335 {
336 	struct mddev *mddev = arg;
337 	struct md_cluster_info *cinfo = mddev->cluster_info;
338 
339 	pr_info("md-cluster: %s Node %d/%d down. My slot: %d. Initiating recovery.\n",
340 			mddev->bitmap_info.cluster_name,
341 			slot->nodeid, slot->slot,
342 			cinfo->slot_number);
343 	/* deduct one since dlm slot starts from one while the num of
344 	 * cluster-md begins with 0 */
345 	__recover_slot(mddev, slot->slot - 1);
346 }
347 
348 static void recover_done(void *arg, struct dlm_slot *slots,
349 		int num_slots, int our_slot,
350 		uint32_t generation)
351 {
352 	struct mddev *mddev = arg;
353 	struct md_cluster_info *cinfo = mddev->cluster_info;
354 
355 	cinfo->slot_number = our_slot;
356 	/* completion is only need to be complete when node join cluster,
357 	 * it doesn't need to run during another node's failure */
358 	if (test_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state)) {
359 		complete(&cinfo->completion);
360 		clear_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state);
361 	}
362 	clear_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state);
363 }
364 
365 /* the ops is called when node join the cluster, and do lock recovery
366  * if node failure occurs */
367 static const struct dlm_lockspace_ops md_ls_ops = {
368 	.recover_prep = recover_prep,
369 	.recover_slot = recover_slot,
370 	.recover_done = recover_done,
371 };
372 
373 /*
374  * The BAST function for the ack lock resource
375  * This function wakes up the receive thread in
376  * order to receive and process the message.
377  */
378 static void ack_bast(void *arg, int mode)
379 {
380 	struct dlm_lock_resource *res = arg;
381 	struct md_cluster_info *cinfo = res->mddev->cluster_info;
382 
383 	if (mode == DLM_LOCK_EX) {
384 		if (test_bit(MD_CLUSTER_ALREADY_IN_CLUSTER, &cinfo->state))
385 			md_wakeup_thread(cinfo->recv_thread);
386 		else
387 			set_bit(MD_CLUSTER_PENDING_RECV_EVENT, &cinfo->state);
388 	}
389 }
390 
391 static void __remove_suspend_info(struct md_cluster_info *cinfo, int slot)
392 {
393 	struct suspend_info *s, *tmp;
394 
395 	list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
396 		if (slot == s->slot) {
397 			list_del(&s->list);
398 			kfree(s);
399 			break;
400 		}
401 }
402 
403 static void remove_suspend_info(struct mddev *mddev, int slot)
404 {
405 	struct md_cluster_info *cinfo = mddev->cluster_info;
406 	spin_lock_irq(&cinfo->suspend_lock);
407 	__remove_suspend_info(cinfo, slot);
408 	spin_unlock_irq(&cinfo->suspend_lock);
409 	mddev->pers->quiesce(mddev, 2);
410 }
411 
412 
413 static void process_suspend_info(struct mddev *mddev,
414 		int slot, sector_t lo, sector_t hi)
415 {
416 	struct md_cluster_info *cinfo = mddev->cluster_info;
417 	struct suspend_info *s;
418 
419 	if (!hi) {
420 		remove_suspend_info(mddev, slot);
421 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
422 		md_wakeup_thread(mddev->thread);
423 		return;
424 	}
425 
426 	/*
427 	 * The bitmaps are not same for different nodes
428 	 * if RESYNCING is happening in one node, then
429 	 * the node which received the RESYNCING message
430 	 * probably will perform resync with the region
431 	 * [lo, hi] again, so we could reduce resync time
432 	 * a lot if we can ensure that the bitmaps among
433 	 * different nodes are match up well.
434 	 *
435 	 * sync_low/hi is used to record the region which
436 	 * arrived in the previous RESYNCING message,
437 	 *
438 	 * Call bitmap_sync_with_cluster to clear
439 	 * NEEDED_MASK and set RESYNC_MASK since
440 	 * resync thread is running in another node,
441 	 * so we don't need to do the resync again
442 	 * with the same section */
443 	bitmap_sync_with_cluster(mddev, cinfo->sync_low,
444 					cinfo->sync_hi,
445 					lo, hi);
446 	cinfo->sync_low = lo;
447 	cinfo->sync_hi = hi;
448 
449 	s = kzalloc(sizeof(struct suspend_info), GFP_KERNEL);
450 	if (!s)
451 		return;
452 	s->slot = slot;
453 	s->lo = lo;
454 	s->hi = hi;
455 	mddev->pers->quiesce(mddev, 1);
456 	mddev->pers->quiesce(mddev, 0);
457 	spin_lock_irq(&cinfo->suspend_lock);
458 	/* Remove existing entry (if exists) before adding */
459 	__remove_suspend_info(cinfo, slot);
460 	list_add(&s->list, &cinfo->suspend_list);
461 	spin_unlock_irq(&cinfo->suspend_lock);
462 	mddev->pers->quiesce(mddev, 2);
463 }
464 
465 static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
466 {
467 	char disk_uuid[64];
468 	struct md_cluster_info *cinfo = mddev->cluster_info;
469 	char event_name[] = "EVENT=ADD_DEVICE";
470 	char raid_slot[16];
471 	char *envp[] = {event_name, disk_uuid, raid_slot, NULL};
472 	int len;
473 
474 	len = snprintf(disk_uuid, 64, "DEVICE_UUID=");
475 	sprintf(disk_uuid + len, "%pU", cmsg->uuid);
476 	snprintf(raid_slot, 16, "RAID_DISK=%d", le32_to_cpu(cmsg->raid_slot));
477 	pr_info("%s:%d Sending kobject change with %s and %s\n", __func__, __LINE__, disk_uuid, raid_slot);
478 	init_completion(&cinfo->newdisk_completion);
479 	set_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
480 	kobject_uevent_env(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE, envp);
481 	wait_for_completion_timeout(&cinfo->newdisk_completion,
482 			NEW_DEV_TIMEOUT);
483 	clear_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
484 }
485 
486 
487 static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
488 {
489 	struct md_cluster_info *cinfo = mddev->cluster_info;
490 	mddev->good_device_nr = le32_to_cpu(msg->raid_slot);
491 	set_bit(MD_RELOAD_SB, &mddev->flags);
492 	dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
493 	md_wakeup_thread(mddev->thread);
494 }
495 
496 static void process_remove_disk(struct mddev *mddev, struct cluster_msg *msg)
497 {
498 	struct md_rdev *rdev = md_find_rdev_nr_rcu(mddev,
499 						   le32_to_cpu(msg->raid_slot));
500 
501 	if (rdev) {
502 		set_bit(ClusterRemove, &rdev->flags);
503 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
504 		md_wakeup_thread(mddev->thread);
505 	}
506 	else
507 		pr_warn("%s: %d Could not find disk(%d) to REMOVE\n",
508 			__func__, __LINE__, le32_to_cpu(msg->raid_slot));
509 }
510 
511 static void process_readd_disk(struct mddev *mddev, struct cluster_msg *msg)
512 {
513 	struct md_rdev *rdev = md_find_rdev_nr_rcu(mddev,
514 						   le32_to_cpu(msg->raid_slot));
515 
516 	if (rdev && test_bit(Faulty, &rdev->flags))
517 		clear_bit(Faulty, &rdev->flags);
518 	else
519 		pr_warn("%s: %d Could not find disk(%d) which is faulty",
520 			__func__, __LINE__, le32_to_cpu(msg->raid_slot));
521 }
522 
523 static int process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
524 {
525 	int ret = 0;
526 
527 	if (WARN(mddev->cluster_info->slot_number - 1 == le32_to_cpu(msg->slot),
528 		"node %d received it's own msg\n", le32_to_cpu(msg->slot)))
529 		return -1;
530 	switch (le32_to_cpu(msg->type)) {
531 	case METADATA_UPDATED:
532 		process_metadata_update(mddev, msg);
533 		break;
534 	case RESYNCING:
535 		process_suspend_info(mddev, le32_to_cpu(msg->slot),
536 				     le64_to_cpu(msg->low),
537 				     le64_to_cpu(msg->high));
538 		break;
539 	case NEWDISK:
540 		process_add_new_disk(mddev, msg);
541 		break;
542 	case REMOVE:
543 		process_remove_disk(mddev, msg);
544 		break;
545 	case RE_ADD:
546 		process_readd_disk(mddev, msg);
547 		break;
548 	case BITMAP_NEEDS_SYNC:
549 		__recover_slot(mddev, le32_to_cpu(msg->slot));
550 		break;
551 	default:
552 		ret = -1;
553 		pr_warn("%s:%d Received unknown message from %d\n",
554 			__func__, __LINE__, msg->slot);
555 	}
556 	return ret;
557 }
558 
559 /*
560  * thread for receiving message
561  */
562 static void recv_daemon(struct md_thread *thread)
563 {
564 	struct md_cluster_info *cinfo = thread->mddev->cluster_info;
565 	struct dlm_lock_resource *ack_lockres = cinfo->ack_lockres;
566 	struct dlm_lock_resource *message_lockres = cinfo->message_lockres;
567 	struct cluster_msg msg;
568 	int ret;
569 
570 	mutex_lock(&cinfo->recv_mutex);
571 	/*get CR on Message*/
572 	if (dlm_lock_sync(message_lockres, DLM_LOCK_CR)) {
573 		pr_err("md/raid1:failed to get CR on MESSAGE\n");
574 		mutex_unlock(&cinfo->recv_mutex);
575 		return;
576 	}
577 
578 	/* read lvb and wake up thread to process this message_lockres */
579 	memcpy(&msg, message_lockres->lksb.sb_lvbptr, sizeof(struct cluster_msg));
580 	ret = process_recvd_msg(thread->mddev, &msg);
581 	if (ret)
582 		goto out;
583 
584 	/*release CR on ack_lockres*/
585 	ret = dlm_unlock_sync(ack_lockres);
586 	if (unlikely(ret != 0))
587 		pr_info("unlock ack failed return %d\n", ret);
588 	/*up-convert to PR on message_lockres*/
589 	ret = dlm_lock_sync(message_lockres, DLM_LOCK_PR);
590 	if (unlikely(ret != 0))
591 		pr_info("lock PR on msg failed return %d\n", ret);
592 	/*get CR on ack_lockres again*/
593 	ret = dlm_lock_sync(ack_lockres, DLM_LOCK_CR);
594 	if (unlikely(ret != 0))
595 		pr_info("lock CR on ack failed return %d\n", ret);
596 out:
597 	/*release CR on message_lockres*/
598 	ret = dlm_unlock_sync(message_lockres);
599 	if (unlikely(ret != 0))
600 		pr_info("unlock msg failed return %d\n", ret);
601 	mutex_unlock(&cinfo->recv_mutex);
602 }
603 
604 /* lock_token()
605  * Takes the lock on the TOKEN lock resource so no other
606  * node can communicate while the operation is underway.
607  */
608 static int lock_token(struct md_cluster_info *cinfo)
609 {
610 	int error;
611 
612 	error = dlm_lock_sync(cinfo->token_lockres, DLM_LOCK_EX);
613 	if (error)
614 		pr_err("md-cluster(%s:%d): failed to get EX on TOKEN (%d)\n",
615 				__func__, __LINE__, error);
616 
617 	/* Lock the receive sequence */
618 	mutex_lock(&cinfo->recv_mutex);
619 	return error;
620 }
621 
622 /* lock_comm()
623  * Sets the MD_CLUSTER_SEND_LOCK bit to lock the send channel.
624  */
625 static int lock_comm(struct md_cluster_info *cinfo)
626 {
627 	wait_event(cinfo->wait,
628 		   !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state));
629 
630 	return lock_token(cinfo);
631 }
632 
633 static void unlock_comm(struct md_cluster_info *cinfo)
634 {
635 	WARN_ON(cinfo->token_lockres->mode != DLM_LOCK_EX);
636 	mutex_unlock(&cinfo->recv_mutex);
637 	dlm_unlock_sync(cinfo->token_lockres);
638 	clear_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state);
639 	wake_up(&cinfo->wait);
640 }
641 
642 /* __sendmsg()
643  * This function performs the actual sending of the message. This function is
644  * usually called after performing the encompassing operation
645  * The function:
646  * 1. Grabs the message lockresource in EX mode
647  * 2. Copies the message to the message LVB
648  * 3. Downconverts message lockresource to CW
649  * 4. Upconverts ack lock resource from CR to EX. This forces the BAST on other nodes
650  *    and the other nodes read the message. The thread will wait here until all other
651  *    nodes have released ack lock resource.
652  * 5. Downconvert ack lockresource to CR
653  */
654 static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
655 {
656 	int error;
657 	int slot = cinfo->slot_number - 1;
658 
659 	cmsg->slot = cpu_to_le32(slot);
660 	/*get EX on Message*/
661 	error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_EX);
662 	if (error) {
663 		pr_err("md-cluster: failed to get EX on MESSAGE (%d)\n", error);
664 		goto failed_message;
665 	}
666 
667 	memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg,
668 			sizeof(struct cluster_msg));
669 	/*down-convert EX to CW on Message*/
670 	error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_CW);
671 	if (error) {
672 		pr_err("md-cluster: failed to convert EX to CW on MESSAGE(%d)\n",
673 				error);
674 		goto failed_ack;
675 	}
676 
677 	/*up-convert CR to EX on Ack*/
678 	error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_EX);
679 	if (error) {
680 		pr_err("md-cluster: failed to convert CR to EX on ACK(%d)\n",
681 				error);
682 		goto failed_ack;
683 	}
684 
685 	/*down-convert EX to CR on Ack*/
686 	error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR);
687 	if (error) {
688 		pr_err("md-cluster: failed to convert EX to CR on ACK(%d)\n",
689 				error);
690 		goto failed_ack;
691 	}
692 
693 failed_ack:
694 	error = dlm_unlock_sync(cinfo->message_lockres);
695 	if (unlikely(error != 0)) {
696 		pr_err("md-cluster: failed convert to NL on MESSAGE(%d)\n",
697 			error);
698 		/* in case the message can't be released due to some reason */
699 		goto failed_ack;
700 	}
701 failed_message:
702 	return error;
703 }
704 
705 static int sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
706 {
707 	int ret;
708 
709 	lock_comm(cinfo);
710 	ret = __sendmsg(cinfo, cmsg);
711 	unlock_comm(cinfo);
712 	return ret;
713 }
714 
715 static int gather_all_resync_info(struct mddev *mddev, int total_slots)
716 {
717 	struct md_cluster_info *cinfo = mddev->cluster_info;
718 	int i, ret = 0;
719 	struct dlm_lock_resource *bm_lockres;
720 	struct suspend_info *s;
721 	char str[64];
722 	sector_t lo, hi;
723 
724 
725 	for (i = 0; i < total_slots; i++) {
726 		memset(str, '\0', 64);
727 		snprintf(str, 64, "bitmap%04d", i);
728 		bm_lockres = lockres_init(mddev, str, NULL, 1);
729 		if (!bm_lockres)
730 			return -ENOMEM;
731 		if (i == (cinfo->slot_number - 1)) {
732 			lockres_free(bm_lockres);
733 			continue;
734 		}
735 
736 		bm_lockres->flags |= DLM_LKF_NOQUEUE;
737 		ret = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
738 		if (ret == -EAGAIN) {
739 			memset(bm_lockres->lksb.sb_lvbptr, '\0', LVB_SIZE);
740 			s = read_resync_info(mddev, bm_lockres);
741 			if (s) {
742 				pr_info("%s:%d Resync[%llu..%llu] in progress on %d\n",
743 						__func__, __LINE__,
744 						(unsigned long long) s->lo,
745 						(unsigned long long) s->hi, i);
746 				spin_lock_irq(&cinfo->suspend_lock);
747 				s->slot = i;
748 				list_add(&s->list, &cinfo->suspend_list);
749 				spin_unlock_irq(&cinfo->suspend_lock);
750 			}
751 			ret = 0;
752 			lockres_free(bm_lockres);
753 			continue;
754 		}
755 		if (ret) {
756 			lockres_free(bm_lockres);
757 			goto out;
758 		}
759 
760 		/* Read the disk bitmap sb and check if it needs recovery */
761 		ret = bitmap_copy_from_slot(mddev, i, &lo, &hi, false);
762 		if (ret) {
763 			pr_warn("md-cluster: Could not gather bitmaps from slot %d", i);
764 			lockres_free(bm_lockres);
765 			continue;
766 		}
767 		if ((hi > 0) && (lo < mddev->recovery_cp)) {
768 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
769 			mddev->recovery_cp = lo;
770 			md_check_recovery(mddev);
771 		}
772 
773 		dlm_unlock_sync(bm_lockres);
774 		lockres_free(bm_lockres);
775 	}
776 out:
777 	return ret;
778 }
779 
780 static int join(struct mddev *mddev, int nodes)
781 {
782 	struct md_cluster_info *cinfo;
783 	int ret, ops_rv;
784 	char str[64];
785 
786 	cinfo = kzalloc(sizeof(struct md_cluster_info), GFP_KERNEL);
787 	if (!cinfo)
788 		return -ENOMEM;
789 
790 	INIT_LIST_HEAD(&cinfo->suspend_list);
791 	spin_lock_init(&cinfo->suspend_lock);
792 	init_completion(&cinfo->completion);
793 	set_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state);
794 	init_waitqueue_head(&cinfo->wait);
795 	mutex_init(&cinfo->recv_mutex);
796 
797 	mddev->cluster_info = cinfo;
798 
799 	memset(str, 0, 64);
800 	sprintf(str, "%pU", mddev->uuid);
801 	ret = dlm_new_lockspace(str, mddev->bitmap_info.cluster_name,
802 				DLM_LSFL_FS, LVB_SIZE,
803 				&md_ls_ops, mddev, &ops_rv, &cinfo->lockspace);
804 	if (ret)
805 		goto err;
806 	wait_for_completion(&cinfo->completion);
807 	if (nodes < cinfo->slot_number) {
808 		pr_err("md-cluster: Slot allotted(%d) is greater than available slots(%d).",
809 			cinfo->slot_number, nodes);
810 		ret = -ERANGE;
811 		goto err;
812 	}
813 	/* Initiate the communication resources */
814 	ret = -ENOMEM;
815 	cinfo->recv_thread = md_register_thread(recv_daemon, mddev, "cluster_recv");
816 	if (!cinfo->recv_thread) {
817 		pr_err("md-cluster: cannot allocate memory for recv_thread!\n");
818 		goto err;
819 	}
820 	cinfo->message_lockres = lockres_init(mddev, "message", NULL, 1);
821 	if (!cinfo->message_lockres)
822 		goto err;
823 	cinfo->token_lockres = lockres_init(mddev, "token", NULL, 0);
824 	if (!cinfo->token_lockres)
825 		goto err;
826 	cinfo->no_new_dev_lockres = lockres_init(mddev, "no-new-dev", NULL, 0);
827 	if (!cinfo->no_new_dev_lockres)
828 		goto err;
829 
830 	ret = dlm_lock_sync(cinfo->token_lockres, DLM_LOCK_EX);
831 	if (ret) {
832 		ret = -EAGAIN;
833 		pr_err("md-cluster: can't join cluster to avoid lock issue\n");
834 		goto err;
835 	}
836 	cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);
837 	if (!cinfo->ack_lockres)
838 		goto err;
839 	/* get sync CR lock on ACK. */
840 	if (dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR))
841 		pr_err("md-cluster: failed to get a sync CR lock on ACK!(%d)\n",
842 				ret);
843 	dlm_unlock_sync(cinfo->token_lockres);
844 	/* get sync CR lock on no-new-dev. */
845 	if (dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR))
846 		pr_err("md-cluster: failed to get a sync CR lock on no-new-dev!(%d)\n", ret);
847 
848 
849 	pr_info("md-cluster: Joined cluster %s slot %d\n", str, cinfo->slot_number);
850 	snprintf(str, 64, "bitmap%04d", cinfo->slot_number - 1);
851 	cinfo->bitmap_lockres = lockres_init(mddev, str, NULL, 1);
852 	if (!cinfo->bitmap_lockres)
853 		goto err;
854 	if (dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW)) {
855 		pr_err("Failed to get bitmap lock\n");
856 		ret = -EINVAL;
857 		goto err;
858 	}
859 
860 	cinfo->resync_lockres = lockres_init(mddev, "resync", NULL, 0);
861 	if (!cinfo->resync_lockres)
862 		goto err;
863 
864 	return 0;
865 err:
866 	md_unregister_thread(&cinfo->recovery_thread);
867 	md_unregister_thread(&cinfo->recv_thread);
868 	lockres_free(cinfo->message_lockres);
869 	lockres_free(cinfo->token_lockres);
870 	lockres_free(cinfo->ack_lockres);
871 	lockres_free(cinfo->no_new_dev_lockres);
872 	lockres_free(cinfo->resync_lockres);
873 	lockres_free(cinfo->bitmap_lockres);
874 	if (cinfo->lockspace)
875 		dlm_release_lockspace(cinfo->lockspace, 2);
876 	mddev->cluster_info = NULL;
877 	kfree(cinfo);
878 	return ret;
879 }
880 
881 static void load_bitmaps(struct mddev *mddev, int total_slots)
882 {
883 	struct md_cluster_info *cinfo = mddev->cluster_info;
884 
885 	/* load all the node's bitmap info for resync */
886 	if (gather_all_resync_info(mddev, total_slots))
887 		pr_err("md-cluster: failed to gather all resyn infos\n");
888 	set_bit(MD_CLUSTER_ALREADY_IN_CLUSTER, &cinfo->state);
889 	/* wake up recv thread in case something need to be handled */
890 	if (test_and_clear_bit(MD_CLUSTER_PENDING_RECV_EVENT, &cinfo->state))
891 		md_wakeup_thread(cinfo->recv_thread);
892 }
893 
894 static void resync_bitmap(struct mddev *mddev)
895 {
896 	struct md_cluster_info *cinfo = mddev->cluster_info;
897 	struct cluster_msg cmsg = {0};
898 	int err;
899 
900 	cmsg.type = cpu_to_le32(BITMAP_NEEDS_SYNC);
901 	err = sendmsg(cinfo, &cmsg);
902 	if (err)
903 		pr_err("%s:%d: failed to send BITMAP_NEEDS_SYNC message (%d)\n",
904 			__func__, __LINE__, err);
905 }
906 
907 static void unlock_all_bitmaps(struct mddev *mddev);
908 static int leave(struct mddev *mddev)
909 {
910 	struct md_cluster_info *cinfo = mddev->cluster_info;
911 
912 	if (!cinfo)
913 		return 0;
914 
915 	/* BITMAP_NEEDS_SYNC message should be sent when node
916 	 * is leaving the cluster with dirty bitmap, also we
917 	 * can only deliver it when dlm connection is available */
918 	if (cinfo->slot_number > 0 && mddev->recovery_cp != MaxSector)
919 		resync_bitmap(mddev);
920 
921 	md_unregister_thread(&cinfo->recovery_thread);
922 	md_unregister_thread(&cinfo->recv_thread);
923 	lockres_free(cinfo->message_lockres);
924 	lockres_free(cinfo->token_lockres);
925 	lockres_free(cinfo->ack_lockres);
926 	lockres_free(cinfo->no_new_dev_lockres);
927 	lockres_free(cinfo->resync_lockres);
928 	lockres_free(cinfo->bitmap_lockres);
929 	unlock_all_bitmaps(mddev);
930 	dlm_release_lockspace(cinfo->lockspace, 2);
931 	return 0;
932 }
933 
934 /* slot_number(): Returns the MD slot number to use
935  * DLM starts the slot numbers from 1, wheras cluster-md
936  * wants the number to be from zero, so we deduct one
937  */
938 static int slot_number(struct mddev *mddev)
939 {
940 	struct md_cluster_info *cinfo = mddev->cluster_info;
941 
942 	return cinfo->slot_number - 1;
943 }
944 
945 /*
946  * Check if the communication is already locked, else lock the communication
947  * channel.
948  * If it is already locked, token is in EX mode, and hence lock_token()
949  * should not be called.
950  */
951 static int metadata_update_start(struct mddev *mddev)
952 {
953 	struct md_cluster_info *cinfo = mddev->cluster_info;
954 
955 	wait_event(cinfo->wait,
956 		   !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state) ||
957 		   test_and_clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state));
958 
959 	/* If token is already locked, return 0 */
960 	if (cinfo->token_lockres->mode == DLM_LOCK_EX)
961 		return 0;
962 
963 	return lock_token(cinfo);
964 }
965 
966 static int metadata_update_finish(struct mddev *mddev)
967 {
968 	struct md_cluster_info *cinfo = mddev->cluster_info;
969 	struct cluster_msg cmsg;
970 	struct md_rdev *rdev;
971 	int ret = 0;
972 	int raid_slot = -1;
973 
974 	memset(&cmsg, 0, sizeof(cmsg));
975 	cmsg.type = cpu_to_le32(METADATA_UPDATED);
976 	/* Pick up a good active device number to send.
977 	 */
978 	rdev_for_each(rdev, mddev)
979 		if (rdev->raid_disk > -1 && !test_bit(Faulty, &rdev->flags)) {
980 			raid_slot = rdev->desc_nr;
981 			break;
982 		}
983 	if (raid_slot >= 0) {
984 		cmsg.raid_slot = cpu_to_le32(raid_slot);
985 		ret = __sendmsg(cinfo, &cmsg);
986 	} else
987 		pr_warn("md-cluster: No good device id found to send\n");
988 	clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
989 	unlock_comm(cinfo);
990 	return ret;
991 }
992 
993 static void metadata_update_cancel(struct mddev *mddev)
994 {
995 	struct md_cluster_info *cinfo = mddev->cluster_info;
996 	clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
997 	unlock_comm(cinfo);
998 }
999 
1000 static int resync_start(struct mddev *mddev)
1001 {
1002 	struct md_cluster_info *cinfo = mddev->cluster_info;
1003 	return dlm_lock_sync(cinfo->resync_lockres, DLM_LOCK_EX);
1004 }
1005 
1006 static int resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
1007 {
1008 	struct md_cluster_info *cinfo = mddev->cluster_info;
1009 	struct resync_info ri;
1010 	struct cluster_msg cmsg = {0};
1011 
1012 	/* do not send zero again, if we have sent before */
1013 	if (hi == 0) {
1014 		memcpy(&ri, cinfo->bitmap_lockres->lksb.sb_lvbptr, sizeof(struct resync_info));
1015 		if (le64_to_cpu(ri.hi) == 0)
1016 			return 0;
1017 	}
1018 
1019 	add_resync_info(cinfo->bitmap_lockres, lo, hi);
1020 	/* Re-acquire the lock to refresh LVB */
1021 	dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW);
1022 	cmsg.type = cpu_to_le32(RESYNCING);
1023 	cmsg.low = cpu_to_le64(lo);
1024 	cmsg.high = cpu_to_le64(hi);
1025 
1026 	return sendmsg(cinfo, &cmsg);
1027 }
1028 
1029 static int resync_finish(struct mddev *mddev)
1030 {
1031 	struct md_cluster_info *cinfo = mddev->cluster_info;
1032 	dlm_unlock_sync(cinfo->resync_lockres);
1033 	return resync_info_update(mddev, 0, 0);
1034 }
1035 
1036 static int area_resyncing(struct mddev *mddev, int direction,
1037 		sector_t lo, sector_t hi)
1038 {
1039 	struct md_cluster_info *cinfo = mddev->cluster_info;
1040 	int ret = 0;
1041 	struct suspend_info *s;
1042 
1043 	if ((direction == READ) &&
1044 		test_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state))
1045 		return 1;
1046 
1047 	spin_lock_irq(&cinfo->suspend_lock);
1048 	if (list_empty(&cinfo->suspend_list))
1049 		goto out;
1050 	list_for_each_entry(s, &cinfo->suspend_list, list)
1051 		if (hi > s->lo && lo < s->hi) {
1052 			ret = 1;
1053 			break;
1054 		}
1055 out:
1056 	spin_unlock_irq(&cinfo->suspend_lock);
1057 	return ret;
1058 }
1059 
1060 /* add_new_disk() - initiates a disk add
1061  * However, if this fails before writing md_update_sb(),
1062  * add_new_disk_cancel() must be called to release token lock
1063  */
1064 static int add_new_disk(struct mddev *mddev, struct md_rdev *rdev)
1065 {
1066 	struct md_cluster_info *cinfo = mddev->cluster_info;
1067 	struct cluster_msg cmsg;
1068 	int ret = 0;
1069 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1070 	char *uuid = sb->device_uuid;
1071 
1072 	memset(&cmsg, 0, sizeof(cmsg));
1073 	cmsg.type = cpu_to_le32(NEWDISK);
1074 	memcpy(cmsg.uuid, uuid, 16);
1075 	cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1076 	lock_comm(cinfo);
1077 	ret = __sendmsg(cinfo, &cmsg);
1078 	if (ret)
1079 		return ret;
1080 	cinfo->no_new_dev_lockres->flags |= DLM_LKF_NOQUEUE;
1081 	ret = dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_EX);
1082 	cinfo->no_new_dev_lockres->flags &= ~DLM_LKF_NOQUEUE;
1083 	/* Some node does not "see" the device */
1084 	if (ret == -EAGAIN)
1085 		ret = -ENOENT;
1086 	if (ret)
1087 		unlock_comm(cinfo);
1088 	else {
1089 		dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
1090 		/* Since MD_CHANGE_DEVS will be set in add_bound_rdev which
1091 		 * will run soon after add_new_disk, the below path will be
1092 		 * invoked:
1093 		 *   md_wakeup_thread(mddev->thread)
1094 		 *	-> conf->thread (raid1d)
1095 		 *	-> md_check_recovery -> md_update_sb
1096 		 *	-> metadata_update_start/finish
1097 		 * MD_CLUSTER_SEND_LOCKED_ALREADY will be cleared eventually.
1098 		 *
1099 		 * For other failure cases, metadata_update_cancel and
1100 		 * add_new_disk_cancel also clear below bit as well.
1101 		 * */
1102 		set_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
1103 		wake_up(&cinfo->wait);
1104 	}
1105 	return ret;
1106 }
1107 
1108 static void add_new_disk_cancel(struct mddev *mddev)
1109 {
1110 	struct md_cluster_info *cinfo = mddev->cluster_info;
1111 	clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
1112 	unlock_comm(cinfo);
1113 }
1114 
1115 static int new_disk_ack(struct mddev *mddev, bool ack)
1116 {
1117 	struct md_cluster_info *cinfo = mddev->cluster_info;
1118 
1119 	if (!test_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state)) {
1120 		pr_warn("md-cluster(%s): Spurious cluster confirmation\n", mdname(mddev));
1121 		return -EINVAL;
1122 	}
1123 
1124 	if (ack)
1125 		dlm_unlock_sync(cinfo->no_new_dev_lockres);
1126 	complete(&cinfo->newdisk_completion);
1127 	return 0;
1128 }
1129 
1130 static int remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1131 {
1132 	struct cluster_msg cmsg = {0};
1133 	struct md_cluster_info *cinfo = mddev->cluster_info;
1134 	cmsg.type = cpu_to_le32(REMOVE);
1135 	cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1136 	return sendmsg(cinfo, &cmsg);
1137 }
1138 
1139 static int lock_all_bitmaps(struct mddev *mddev)
1140 {
1141 	int slot, my_slot, ret, held = 1, i = 0;
1142 	char str[64];
1143 	struct md_cluster_info *cinfo = mddev->cluster_info;
1144 
1145 	cinfo->other_bitmap_lockres = kzalloc((mddev->bitmap_info.nodes - 1) *
1146 					     sizeof(struct dlm_lock_resource *),
1147 					     GFP_KERNEL);
1148 	if (!cinfo->other_bitmap_lockres) {
1149 		pr_err("md: can't alloc mem for other bitmap locks\n");
1150 		return 0;
1151 	}
1152 
1153 	my_slot = slot_number(mddev);
1154 	for (slot = 0; slot < mddev->bitmap_info.nodes; slot++) {
1155 		if (slot == my_slot)
1156 			continue;
1157 
1158 		memset(str, '\0', 64);
1159 		snprintf(str, 64, "bitmap%04d", slot);
1160 		cinfo->other_bitmap_lockres[i] = lockres_init(mddev, str, NULL, 1);
1161 		if (!cinfo->other_bitmap_lockres[i])
1162 			return -ENOMEM;
1163 
1164 		cinfo->other_bitmap_lockres[i]->flags |= DLM_LKF_NOQUEUE;
1165 		ret = dlm_lock_sync(cinfo->other_bitmap_lockres[i], DLM_LOCK_PW);
1166 		if (ret)
1167 			held = -1;
1168 		i++;
1169 	}
1170 
1171 	return held;
1172 }
1173 
1174 static void unlock_all_bitmaps(struct mddev *mddev)
1175 {
1176 	struct md_cluster_info *cinfo = mddev->cluster_info;
1177 	int i;
1178 
1179 	/* release other node's bitmap lock if they are existed */
1180 	if (cinfo->other_bitmap_lockres) {
1181 		for (i = 0; i < mddev->bitmap_info.nodes - 1; i++) {
1182 			if (cinfo->other_bitmap_lockres[i]) {
1183 				dlm_unlock_sync(cinfo->other_bitmap_lockres[i]);
1184 				lockres_free(cinfo->other_bitmap_lockres[i]);
1185 			}
1186 		}
1187 		kfree(cinfo->other_bitmap_lockres);
1188 	}
1189 }
1190 
1191 static int gather_bitmaps(struct md_rdev *rdev)
1192 {
1193 	int sn, err;
1194 	sector_t lo, hi;
1195 	struct cluster_msg cmsg = {0};
1196 	struct mddev *mddev = rdev->mddev;
1197 	struct md_cluster_info *cinfo = mddev->cluster_info;
1198 
1199 	cmsg.type = cpu_to_le32(RE_ADD);
1200 	cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1201 	err = sendmsg(cinfo, &cmsg);
1202 	if (err)
1203 		goto out;
1204 
1205 	for (sn = 0; sn < mddev->bitmap_info.nodes; sn++) {
1206 		if (sn == (cinfo->slot_number - 1))
1207 			continue;
1208 		err = bitmap_copy_from_slot(mddev, sn, &lo, &hi, false);
1209 		if (err) {
1210 			pr_warn("md-cluster: Could not gather bitmaps from slot %d", sn);
1211 			goto out;
1212 		}
1213 		if ((hi > 0) && (lo < mddev->recovery_cp))
1214 			mddev->recovery_cp = lo;
1215 	}
1216 out:
1217 	return err;
1218 }
1219 
1220 static struct md_cluster_operations cluster_ops = {
1221 	.join   = join,
1222 	.leave  = leave,
1223 	.slot_number = slot_number,
1224 	.resync_start = resync_start,
1225 	.resync_finish = resync_finish,
1226 	.resync_info_update = resync_info_update,
1227 	.metadata_update_start = metadata_update_start,
1228 	.metadata_update_finish = metadata_update_finish,
1229 	.metadata_update_cancel = metadata_update_cancel,
1230 	.area_resyncing = area_resyncing,
1231 	.add_new_disk = add_new_disk,
1232 	.add_new_disk_cancel = add_new_disk_cancel,
1233 	.new_disk_ack = new_disk_ack,
1234 	.remove_disk = remove_disk,
1235 	.load_bitmaps = load_bitmaps,
1236 	.gather_bitmaps = gather_bitmaps,
1237 	.lock_all_bitmaps = lock_all_bitmaps,
1238 	.unlock_all_bitmaps = unlock_all_bitmaps,
1239 };
1240 
1241 static int __init cluster_init(void)
1242 {
1243 	pr_warn("md-cluster: EXPERIMENTAL. Use with caution\n");
1244 	pr_info("Registering Cluster MD functions\n");
1245 	register_md_cluster_operations(&cluster_ops, THIS_MODULE);
1246 	return 0;
1247 }
1248 
1249 static void cluster_exit(void)
1250 {
1251 	unregister_md_cluster_operations();
1252 }
1253 
1254 module_init(cluster_init);
1255 module_exit(cluster_exit);
1256 MODULE_AUTHOR("SUSE");
1257 MODULE_LICENSE("GPL");
1258 MODULE_DESCRIPTION("Clustering support for MD");
1259