1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 **  Copyright (C) 2005-2011 Red Hat, Inc.  All rights reserved.
6 **
7 **
8 *******************************************************************************
9 ******************************************************************************/
10 
11 #include "dlm_internal.h"
12 #include "lockspace.h"
13 #include "member.h"
14 #include "recoverd.h"
15 #include "recover.h"
16 #include "rcom.h"
17 #include "config.h"
18 #include "midcomms.h"
19 #include "lowcomms.h"
20 
dlm_slots_version(struct dlm_header * h)21 int dlm_slots_version(struct dlm_header *h)
22 {
23 	if ((le32_to_cpu(h->h_version) & 0x0000FFFF) < DLM_HEADER_SLOTS)
24 		return 0;
25 	return 1;
26 }
27 
dlm_slot_save(struct dlm_ls * ls,struct dlm_rcom * rc,struct dlm_member * memb)28 void dlm_slot_save(struct dlm_ls *ls, struct dlm_rcom *rc,
29 		   struct dlm_member *memb)
30 {
31 	struct rcom_config *rf = (struct rcom_config *)rc->rc_buf;
32 
33 	if (!dlm_slots_version(&rc->rc_header))
34 		return;
35 
36 	memb->slot = le16_to_cpu(rf->rf_our_slot);
37 	memb->generation = le32_to_cpu(rf->rf_generation);
38 }
39 
dlm_slots_copy_out(struct dlm_ls * ls,struct dlm_rcom * rc)40 void dlm_slots_copy_out(struct dlm_ls *ls, struct dlm_rcom *rc)
41 {
42 	struct dlm_slot *slot;
43 	struct rcom_slot *ro;
44 	int i;
45 
46 	ro = (struct rcom_slot *)(rc->rc_buf + sizeof(struct rcom_config));
47 
48 	/* ls_slots array is sparse, but not rcom_slots */
49 
50 	for (i = 0; i < ls->ls_slots_size; i++) {
51 		slot = &ls->ls_slots[i];
52 		if (!slot->nodeid)
53 			continue;
54 		ro->ro_nodeid = cpu_to_le32(slot->nodeid);
55 		ro->ro_slot = cpu_to_le16(slot->slot);
56 		ro++;
57 	}
58 }
59 
60 #define SLOT_DEBUG_LINE 128
61 
log_slots(struct dlm_ls * ls,uint32_t gen,int num_slots,struct rcom_slot * ro0,struct dlm_slot * array,int array_size)62 static void log_slots(struct dlm_ls *ls, uint32_t gen, int num_slots,
63 		      struct rcom_slot *ro0, struct dlm_slot *array,
64 		      int array_size)
65 {
66 	char line[SLOT_DEBUG_LINE];
67 	int len = SLOT_DEBUG_LINE - 1;
68 	int pos = 0;
69 	int ret, i;
70 
71 	memset(line, 0, sizeof(line));
72 
73 	if (array) {
74 		for (i = 0; i < array_size; i++) {
75 			if (!array[i].nodeid)
76 				continue;
77 
78 			ret = snprintf(line + pos, len - pos, " %d:%d",
79 				       array[i].slot, array[i].nodeid);
80 			if (ret >= len - pos)
81 				break;
82 			pos += ret;
83 		}
84 	} else if (ro0) {
85 		for (i = 0; i < num_slots; i++) {
86 			ret = snprintf(line + pos, len - pos, " %d:%d",
87 				       ro0[i].ro_slot, ro0[i].ro_nodeid);
88 			if (ret >= len - pos)
89 				break;
90 			pos += ret;
91 		}
92 	}
93 
94 	log_rinfo(ls, "generation %u slots %d%s", gen, num_slots, line);
95 }
96 
dlm_slots_copy_in(struct dlm_ls * ls)97 int dlm_slots_copy_in(struct dlm_ls *ls)
98 {
99 	struct dlm_member *memb;
100 	struct dlm_rcom *rc = ls->ls_recover_buf;
101 	struct rcom_config *rf = (struct rcom_config *)rc->rc_buf;
102 	struct rcom_slot *ro0, *ro;
103 	int our_nodeid = dlm_our_nodeid();
104 	int i, num_slots;
105 	uint32_t gen;
106 
107 	if (!dlm_slots_version(&rc->rc_header))
108 		return -1;
109 
110 	gen = le32_to_cpu(rf->rf_generation);
111 	if (gen <= ls->ls_generation) {
112 		log_error(ls, "dlm_slots_copy_in gen %u old %u",
113 			  gen, ls->ls_generation);
114 	}
115 	ls->ls_generation = gen;
116 
117 	num_slots = le16_to_cpu(rf->rf_num_slots);
118 	if (!num_slots)
119 		return -1;
120 
121 	ro0 = (struct rcom_slot *)(rc->rc_buf + sizeof(struct rcom_config));
122 
123 	log_slots(ls, gen, num_slots, ro0, NULL, 0);
124 
125 	list_for_each_entry(memb, &ls->ls_nodes, list) {
126 		for (i = 0, ro = ro0; i < num_slots; i++, ro++) {
127 			if (le32_to_cpu(ro->ro_nodeid) != memb->nodeid)
128 				continue;
129 			memb->slot = le16_to_cpu(ro->ro_slot);
130 			memb->slot_prev = memb->slot;
131 			break;
132 		}
133 
134 		if (memb->nodeid == our_nodeid) {
135 			if (ls->ls_slot && ls->ls_slot != memb->slot) {
136 				log_error(ls, "dlm_slots_copy_in our slot "
137 					  "changed %d %d", ls->ls_slot,
138 					  memb->slot);
139 				return -1;
140 			}
141 
142 			if (!ls->ls_slot)
143 				ls->ls_slot = memb->slot;
144 		}
145 
146 		if (!memb->slot) {
147 			log_error(ls, "dlm_slots_copy_in nodeid %d no slot",
148 				   memb->nodeid);
149 			return -1;
150 		}
151 	}
152 
153 	return 0;
154 }
155 
156 /* for any nodes that do not support slots, we will not have set memb->slot
157    in wait_status_all(), so memb->slot will remain -1, and we will not
158    assign slots or set ls_num_slots here */
159 
dlm_slots_assign(struct dlm_ls * ls,int * num_slots,int * slots_size,struct dlm_slot ** slots_out,uint32_t * gen_out)160 int dlm_slots_assign(struct dlm_ls *ls, int *num_slots, int *slots_size,
161 		     struct dlm_slot **slots_out, uint32_t *gen_out)
162 {
163 	struct dlm_member *memb;
164 	struct dlm_slot *array;
165 	int our_nodeid = dlm_our_nodeid();
166 	int array_size, max_slots, i;
167 	int need = 0;
168 	int max = 0;
169 	int num = 0;
170 	uint32_t gen = 0;
171 
172 	/* our own memb struct will have slot -1 gen 0 */
173 
174 	list_for_each_entry(memb, &ls->ls_nodes, list) {
175 		if (memb->nodeid == our_nodeid) {
176 			memb->slot = ls->ls_slot;
177 			memb->generation = ls->ls_generation;
178 			break;
179 		}
180 	}
181 
182 	list_for_each_entry(memb, &ls->ls_nodes, list) {
183 		if (memb->generation > gen)
184 			gen = memb->generation;
185 
186 		/* node doesn't support slots */
187 
188 		if (memb->slot == -1)
189 			return -1;
190 
191 		/* node needs a slot assigned */
192 
193 		if (!memb->slot)
194 			need++;
195 
196 		/* node has a slot assigned */
197 
198 		num++;
199 
200 		if (!max || max < memb->slot)
201 			max = memb->slot;
202 
203 		/* sanity check, once slot is assigned it shouldn't change */
204 
205 		if (memb->slot_prev && memb->slot && memb->slot_prev != memb->slot) {
206 			log_error(ls, "nodeid %d slot changed %d %d",
207 				  memb->nodeid, memb->slot_prev, memb->slot);
208 			return -1;
209 		}
210 		memb->slot_prev = memb->slot;
211 	}
212 
213 	array_size = max + need;
214 	array = kcalloc(array_size, sizeof(*array), GFP_NOFS);
215 	if (!array)
216 		return -ENOMEM;
217 
218 	num = 0;
219 
220 	/* fill in slots (offsets) that are used */
221 
222 	list_for_each_entry(memb, &ls->ls_nodes, list) {
223 		if (!memb->slot)
224 			continue;
225 
226 		if (memb->slot > array_size) {
227 			log_error(ls, "invalid slot number %d", memb->slot);
228 			kfree(array);
229 			return -1;
230 		}
231 
232 		array[memb->slot - 1].nodeid = memb->nodeid;
233 		array[memb->slot - 1].slot = memb->slot;
234 		num++;
235 	}
236 
237 	/* assign new slots from unused offsets */
238 
239 	list_for_each_entry(memb, &ls->ls_nodes, list) {
240 		if (memb->slot)
241 			continue;
242 
243 		for (i = 0; i < array_size; i++) {
244 			if (array[i].nodeid)
245 				continue;
246 
247 			memb->slot = i + 1;
248 			memb->slot_prev = memb->slot;
249 			array[i].nodeid = memb->nodeid;
250 			array[i].slot = memb->slot;
251 			num++;
252 
253 			if (!ls->ls_slot && memb->nodeid == our_nodeid)
254 				ls->ls_slot = memb->slot;
255 			break;
256 		}
257 
258 		if (!memb->slot) {
259 			log_error(ls, "no free slot found");
260 			kfree(array);
261 			return -1;
262 		}
263 	}
264 
265 	gen++;
266 
267 	log_slots(ls, gen, num, NULL, array, array_size);
268 
269 	max_slots = (DLM_MAX_APP_BUFSIZE - sizeof(struct dlm_rcom) -
270 		     sizeof(struct rcom_config)) / sizeof(struct rcom_slot);
271 
272 	if (num > max_slots) {
273 		log_error(ls, "num_slots %d exceeds max_slots %d",
274 			  num, max_slots);
275 		kfree(array);
276 		return -1;
277 	}
278 
279 	*gen_out = gen;
280 	*slots_out = array;
281 	*slots_size = array_size;
282 	*num_slots = num;
283 	return 0;
284 }
285 
add_ordered_member(struct dlm_ls * ls,struct dlm_member * new)286 static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
287 {
288 	struct dlm_member *memb = NULL;
289 	struct list_head *tmp;
290 	struct list_head *newlist = &new->list;
291 	struct list_head *head = &ls->ls_nodes;
292 
293 	list_for_each(tmp, head) {
294 		memb = list_entry(tmp, struct dlm_member, list);
295 		if (new->nodeid < memb->nodeid)
296 			break;
297 	}
298 
299 	if (!memb)
300 		list_add_tail(newlist, head);
301 	else {
302 		/* FIXME: can use list macro here */
303 		newlist->prev = tmp->prev;
304 		newlist->next = tmp;
305 		tmp->prev->next = newlist;
306 		tmp->prev = newlist;
307 	}
308 }
309 
dlm_add_member(struct dlm_ls * ls,struct dlm_config_node * node)310 static int dlm_add_member(struct dlm_ls *ls, struct dlm_config_node *node)
311 {
312 	struct dlm_member *memb;
313 	int error;
314 
315 	memb = kzalloc(sizeof(*memb), GFP_NOFS);
316 	if (!memb)
317 		return -ENOMEM;
318 
319 	error = dlm_lowcomms_connect_node(node->nodeid);
320 	if (error < 0) {
321 		kfree(memb);
322 		return error;
323 	}
324 
325 	memb->nodeid = node->nodeid;
326 	memb->weight = node->weight;
327 	memb->comm_seq = node->comm_seq;
328 	dlm_midcomms_add_member(node->nodeid);
329 	add_ordered_member(ls, memb);
330 	ls->ls_num_nodes++;
331 	return 0;
332 }
333 
find_memb(struct list_head * head,int nodeid)334 static struct dlm_member *find_memb(struct list_head *head, int nodeid)
335 {
336 	struct dlm_member *memb;
337 
338 	list_for_each_entry(memb, head, list) {
339 		if (memb->nodeid == nodeid)
340 			return memb;
341 	}
342 	return NULL;
343 }
344 
dlm_is_member(struct dlm_ls * ls,int nodeid)345 int dlm_is_member(struct dlm_ls *ls, int nodeid)
346 {
347 	if (find_memb(&ls->ls_nodes, nodeid))
348 		return 1;
349 	return 0;
350 }
351 
dlm_is_removed(struct dlm_ls * ls,int nodeid)352 int dlm_is_removed(struct dlm_ls *ls, int nodeid)
353 {
354 	if (find_memb(&ls->ls_nodes_gone, nodeid))
355 		return 1;
356 	return 0;
357 }
358 
clear_memb_list(struct list_head * head,void (* after_del)(int nodeid))359 static void clear_memb_list(struct list_head *head,
360 			    void (*after_del)(int nodeid))
361 {
362 	struct dlm_member *memb;
363 
364 	while (!list_empty(head)) {
365 		memb = list_entry(head->next, struct dlm_member, list);
366 		list_del(&memb->list);
367 		if (after_del)
368 			after_del(memb->nodeid);
369 		kfree(memb);
370 	}
371 }
372 
clear_members_cb(int nodeid)373 static void clear_members_cb(int nodeid)
374 {
375 	dlm_midcomms_remove_member(nodeid);
376 }
377 
dlm_clear_members(struct dlm_ls * ls)378 void dlm_clear_members(struct dlm_ls *ls)
379 {
380 	clear_memb_list(&ls->ls_nodes, clear_members_cb);
381 	ls->ls_num_nodes = 0;
382 }
383 
dlm_clear_members_gone(struct dlm_ls * ls)384 void dlm_clear_members_gone(struct dlm_ls *ls)
385 {
386 	clear_memb_list(&ls->ls_nodes_gone, NULL);
387 }
388 
make_member_array(struct dlm_ls * ls)389 static void make_member_array(struct dlm_ls *ls)
390 {
391 	struct dlm_member *memb;
392 	int i, w, x = 0, total = 0, all_zero = 0, *array;
393 
394 	kfree(ls->ls_node_array);
395 	ls->ls_node_array = NULL;
396 
397 	list_for_each_entry(memb, &ls->ls_nodes, list) {
398 		if (memb->weight)
399 			total += memb->weight;
400 	}
401 
402 	/* all nodes revert to weight of 1 if all have weight 0 */
403 
404 	if (!total) {
405 		total = ls->ls_num_nodes;
406 		all_zero = 1;
407 	}
408 
409 	ls->ls_total_weight = total;
410 	array = kmalloc_array(total, sizeof(*array), GFP_NOFS);
411 	if (!array)
412 		return;
413 
414 	list_for_each_entry(memb, &ls->ls_nodes, list) {
415 		if (!all_zero && !memb->weight)
416 			continue;
417 
418 		if (all_zero)
419 			w = 1;
420 		else
421 			w = memb->weight;
422 
423 		DLM_ASSERT(x < total, printk("total %d x %d\n", total, x););
424 
425 		for (i = 0; i < w; i++)
426 			array[x++] = memb->nodeid;
427 	}
428 
429 	ls->ls_node_array = array;
430 }
431 
432 /* send a status request to all members just to establish comms connections */
433 
ping_members(struct dlm_ls * ls)434 static int ping_members(struct dlm_ls *ls)
435 {
436 	struct dlm_member *memb;
437 	int error = 0;
438 
439 	list_for_each_entry(memb, &ls->ls_nodes, list) {
440 		if (dlm_recovery_stopped(ls)) {
441 			error = -EINTR;
442 			break;
443 		}
444 		error = dlm_rcom_status(ls, memb->nodeid, 0);
445 		if (error)
446 			break;
447 	}
448 	if (error)
449 		log_rinfo(ls, "ping_members aborted %d last nodeid %d",
450 			  error, ls->ls_recover_nodeid);
451 	return error;
452 }
453 
dlm_lsop_recover_prep(struct dlm_ls * ls)454 static void dlm_lsop_recover_prep(struct dlm_ls *ls)
455 {
456 	if (!ls->ls_ops || !ls->ls_ops->recover_prep)
457 		return;
458 	ls->ls_ops->recover_prep(ls->ls_ops_arg);
459 }
460 
dlm_lsop_recover_slot(struct dlm_ls * ls,struct dlm_member * memb)461 static void dlm_lsop_recover_slot(struct dlm_ls *ls, struct dlm_member *memb)
462 {
463 	struct dlm_slot slot;
464 	uint32_t seq;
465 	int error;
466 
467 	if (!ls->ls_ops || !ls->ls_ops->recover_slot)
468 		return;
469 
470 	/* if there is no comms connection with this node
471 	   or the present comms connection is newer
472 	   than the one when this member was added, then
473 	   we consider the node to have failed (versus
474 	   being removed due to dlm_release_lockspace) */
475 
476 	error = dlm_comm_seq(memb->nodeid, &seq);
477 
478 	if (!error && seq == memb->comm_seq)
479 		return;
480 
481 	slot.nodeid = memb->nodeid;
482 	slot.slot = memb->slot;
483 
484 	ls->ls_ops->recover_slot(ls->ls_ops_arg, &slot);
485 }
486 
dlm_lsop_recover_done(struct dlm_ls * ls)487 void dlm_lsop_recover_done(struct dlm_ls *ls)
488 {
489 	struct dlm_member *memb;
490 	struct dlm_slot *slots;
491 	int i, num;
492 
493 	if (!ls->ls_ops || !ls->ls_ops->recover_done)
494 		return;
495 
496 	num = ls->ls_num_nodes;
497 	slots = kcalloc(num, sizeof(*slots), GFP_KERNEL);
498 	if (!slots)
499 		return;
500 
501 	i = 0;
502 	list_for_each_entry(memb, &ls->ls_nodes, list) {
503 		if (i == num) {
504 			log_error(ls, "dlm_lsop_recover_done bad num %d", num);
505 			goto out;
506 		}
507 		slots[i].nodeid = memb->nodeid;
508 		slots[i].slot = memb->slot;
509 		i++;
510 	}
511 
512 	ls->ls_ops->recover_done(ls->ls_ops_arg, slots, num,
513 				 ls->ls_slot, ls->ls_generation);
514  out:
515 	kfree(slots);
516 }
517 
find_config_node(struct dlm_recover * rv,int nodeid)518 static struct dlm_config_node *find_config_node(struct dlm_recover *rv,
519 						int nodeid)
520 {
521 	int i;
522 
523 	for (i = 0; i < rv->nodes_count; i++) {
524 		if (rv->nodes[i].nodeid == nodeid)
525 			return &rv->nodes[i];
526 	}
527 	return NULL;
528 }
529 
dlm_recover_members(struct dlm_ls * ls,struct dlm_recover * rv,int * neg_out)530 int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
531 {
532 	struct dlm_member *memb, *safe;
533 	struct dlm_config_node *node;
534 	int i, error, neg = 0, low = -1;
535 
536 	/* previously removed members that we've not finished removing need to
537 	 * count as a negative change so the "neg" recovery steps will happen
538 	 *
539 	 * This functionality must report all member changes to lsops or
540 	 * midcomms layer and must never return before.
541 	 */
542 
543 	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
544 		log_rinfo(ls, "prev removed member %d", memb->nodeid);
545 		neg++;
546 	}
547 
548 	/* move departed members from ls_nodes to ls_nodes_gone */
549 
550 	list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
551 		node = find_config_node(rv, memb->nodeid);
552 		if (node && !node->new)
553 			continue;
554 
555 		if (!node) {
556 			log_rinfo(ls, "remove member %d", memb->nodeid);
557 		} else {
558 			/* removed and re-added */
559 			log_rinfo(ls, "remove member %d comm_seq %u %u",
560 				  memb->nodeid, memb->comm_seq, node->comm_seq);
561 		}
562 
563 		neg++;
564 		list_move(&memb->list, &ls->ls_nodes_gone);
565 		dlm_midcomms_remove_member(memb->nodeid);
566 		ls->ls_num_nodes--;
567 		dlm_lsop_recover_slot(ls, memb);
568 	}
569 
570 	/* add new members to ls_nodes */
571 
572 	for (i = 0; i < rv->nodes_count; i++) {
573 		node = &rv->nodes[i];
574 		if (dlm_is_member(ls, node->nodeid))
575 			continue;
576 		dlm_add_member(ls, node);
577 		log_rinfo(ls, "add member %d", node->nodeid);
578 	}
579 
580 	list_for_each_entry(memb, &ls->ls_nodes, list) {
581 		if (low == -1 || memb->nodeid < low)
582 			low = memb->nodeid;
583 	}
584 	ls->ls_low_nodeid = low;
585 
586 	make_member_array(ls);
587 	*neg_out = neg;
588 
589 	error = ping_members(ls);
590 	log_rinfo(ls, "dlm_recover_members %d nodes", ls->ls_num_nodes);
591 	return error;
592 }
593 
594 /* Userspace guarantees that dlm_ls_stop() has completed on all nodes before
595    dlm_ls_start() is called on any of them to start the new recovery. */
596 
dlm_ls_stop(struct dlm_ls * ls)597 int dlm_ls_stop(struct dlm_ls *ls)
598 {
599 	int new;
600 
601 	/*
602 	 * Prevent dlm_recv from being in the middle of something when we do
603 	 * the stop.  This includes ensuring dlm_recv isn't processing a
604 	 * recovery message (rcom), while dlm_recoverd is aborting and
605 	 * resetting things from an in-progress recovery.  i.e. we want
606 	 * dlm_recoverd to abort its recovery without worrying about dlm_recv
607 	 * processing an rcom at the same time.  Stopping dlm_recv also makes
608 	 * it easy for dlm_receive_message() to check locking stopped and add a
609 	 * message to the requestqueue without races.
610 	 */
611 
612 	down_write(&ls->ls_recv_active);
613 
614 	/*
615 	 * Abort any recovery that's in progress (see RECOVER_STOP,
616 	 * dlm_recovery_stopped()) and tell any other threads running in the
617 	 * dlm to quit any processing (see RUNNING, dlm_locking_stopped()).
618 	 */
619 
620 	spin_lock(&ls->ls_recover_lock);
621 	set_bit(LSFL_RECOVER_STOP, &ls->ls_flags);
622 	new = test_and_clear_bit(LSFL_RUNNING, &ls->ls_flags);
623 	ls->ls_recover_seq++;
624 	spin_unlock(&ls->ls_recover_lock);
625 
626 	/*
627 	 * Let dlm_recv run again, now any normal messages will be saved on the
628 	 * requestqueue for later.
629 	 */
630 
631 	up_write(&ls->ls_recv_active);
632 
633 	/*
634 	 * This in_recovery lock does two things:
635 	 * 1) Keeps this function from returning until all threads are out
636 	 *    of locking routines and locking is truly stopped.
637 	 * 2) Keeps any new requests from being processed until it's unlocked
638 	 *    when recovery is complete.
639 	 */
640 
641 	if (new) {
642 		set_bit(LSFL_RECOVER_DOWN, &ls->ls_flags);
643 		wake_up_process(ls->ls_recoverd_task);
644 		wait_event(ls->ls_recover_lock_wait,
645 			   test_bit(LSFL_RECOVER_LOCK, &ls->ls_flags));
646 	}
647 
648 	/*
649 	 * The recoverd suspend/resume makes sure that dlm_recoverd (if
650 	 * running) has noticed RECOVER_STOP above and quit processing the
651 	 * previous recovery.
652 	 */
653 
654 	dlm_recoverd_suspend(ls);
655 
656 	spin_lock(&ls->ls_recover_lock);
657 	kfree(ls->ls_slots);
658 	ls->ls_slots = NULL;
659 	ls->ls_num_slots = 0;
660 	ls->ls_slots_size = 0;
661 	ls->ls_recover_status = 0;
662 	spin_unlock(&ls->ls_recover_lock);
663 
664 	dlm_recoverd_resume(ls);
665 
666 	if (!ls->ls_recover_begin)
667 		ls->ls_recover_begin = jiffies;
668 
669 	/* call recover_prep ops only once and not multiple times
670 	 * for each possible dlm_ls_stop() when recovery is already
671 	 * stopped.
672 	 *
673 	 * If we successful was able to clear LSFL_RUNNING bit and
674 	 * it was set we know it is the first dlm_ls_stop() call.
675 	 */
676 	if (new)
677 		dlm_lsop_recover_prep(ls);
678 
679 	return 0;
680 }
681 
dlm_ls_start(struct dlm_ls * ls)682 int dlm_ls_start(struct dlm_ls *ls)
683 {
684 	struct dlm_recover *rv, *rv_old;
685 	struct dlm_config_node *nodes = NULL;
686 	int error, count;
687 
688 	rv = kzalloc(sizeof(*rv), GFP_NOFS);
689 	if (!rv)
690 		return -ENOMEM;
691 
692 	error = dlm_config_nodes(ls->ls_name, &nodes, &count);
693 	if (error < 0)
694 		goto fail_rv;
695 
696 	spin_lock(&ls->ls_recover_lock);
697 
698 	/* the lockspace needs to be stopped before it can be started */
699 
700 	if (!dlm_locking_stopped(ls)) {
701 		spin_unlock(&ls->ls_recover_lock);
702 		log_error(ls, "start ignored: lockspace running");
703 		error = -EINVAL;
704 		goto fail;
705 	}
706 
707 	rv->nodes = nodes;
708 	rv->nodes_count = count;
709 	rv->seq = ++ls->ls_recover_seq;
710 	rv_old = ls->ls_recover_args;
711 	ls->ls_recover_args = rv;
712 	spin_unlock(&ls->ls_recover_lock);
713 
714 	if (rv_old) {
715 		log_error(ls, "unused recovery %llx %d",
716 			  (unsigned long long)rv_old->seq, rv_old->nodes_count);
717 		kfree(rv_old->nodes);
718 		kfree(rv_old);
719 	}
720 
721 	set_bit(LSFL_RECOVER_WORK, &ls->ls_flags);
722 	wake_up_process(ls->ls_recoverd_task);
723 	return 0;
724 
725  fail:
726 	kfree(nodes);
727  fail_rv:
728 	kfree(rv);
729 	return error;
730 }
731 
732