xref: /openbmc/linux/fs/dlm/recover.c (revision 1d7c484eeb167fc374294e38ae402de4097c8611)
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
6 **
7 **  This copyrighted material is made available to anyone wishing to use,
8 **  modify, copy, or redistribute it subject to the terms and conditions
9 **  of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13 
14 #include "dlm_internal.h"
15 #include "lockspace.h"
16 #include "dir.h"
17 #include "config.h"
18 #include "ast.h"
19 #include "memory.h"
20 #include "rcom.h"
21 #include "lock.h"
22 #include "lowcomms.h"
23 #include "member.h"
24 #include "recover.h"
25 
26 
27 /*
28  * Recovery waiting routines: these functions wait for a particular reply from
29  * a remote node, or for the remote node to report a certain status.  They need
30  * to abort if the lockspace is stopped indicating a node has failed (perhaps
31  * the one being waited for).
32  */
33 
34 /*
35  * Wait until given function returns non-zero or lockspace is stopped
36  * (LS_RECOVERY_STOP set due to failure of a node in ls_nodes).  When another
37  * function thinks it could have completed the waited-on task, they should wake
38  * up ls_wait_general to get an immediate response rather than waiting for the
39  * timer to detect the result.  A timer wakes us up periodically while waiting
40  * to see if we should abort due to a node failure.  This should only be called
41  * by the dlm_recoverd thread.
42  */
43 
44 static void dlm_wait_timer_fn(unsigned long data)
45 {
46 	struct dlm_ls *ls = (struct dlm_ls *) data;
47 	mod_timer(&ls->ls_timer, jiffies + (dlm_config.ci_recover_timer * HZ));
48 	wake_up(&ls->ls_wait_general);
49 }
50 
51 int dlm_wait_function(struct dlm_ls *ls, int (*testfn) (struct dlm_ls *ls))
52 {
53 	int error = 0;
54 
55 	init_timer(&ls->ls_timer);
56 	ls->ls_timer.function = dlm_wait_timer_fn;
57 	ls->ls_timer.data = (long) ls;
58 	ls->ls_timer.expires = jiffies + (dlm_config.ci_recover_timer * HZ);
59 	add_timer(&ls->ls_timer);
60 
61 	wait_event(ls->ls_wait_general, testfn(ls) || dlm_recovery_stopped(ls));
62 	del_timer_sync(&ls->ls_timer);
63 
64 	if (dlm_recovery_stopped(ls)) {
65 		log_debug(ls, "dlm_wait_function aborted");
66 		error = -EINTR;
67 	}
68 	return error;
69 }
70 
71 /*
72  * An efficient way for all nodes to wait for all others to have a certain
73  * status.  The node with the lowest nodeid polls all the others for their
74  * status (wait_status_all) and all the others poll the node with the low id
75  * for its accumulated result (wait_status_low).  When all nodes have set
76  * status flag X, then status flag X_ALL will be set on the low nodeid.
77  */
78 
79 uint32_t dlm_recover_status(struct dlm_ls *ls)
80 {
81 	uint32_t status;
82 	spin_lock(&ls->ls_recover_lock);
83 	status = ls->ls_recover_status;
84 	spin_unlock(&ls->ls_recover_lock);
85 	return status;
86 }
87 
88 static void _set_recover_status(struct dlm_ls *ls, uint32_t status)
89 {
90 	ls->ls_recover_status |= status;
91 }
92 
93 void dlm_set_recover_status(struct dlm_ls *ls, uint32_t status)
94 {
95 	spin_lock(&ls->ls_recover_lock);
96 	_set_recover_status(ls, status);
97 	spin_unlock(&ls->ls_recover_lock);
98 }
99 
100 static int wait_status_all(struct dlm_ls *ls, uint32_t wait_status,
101 			   int save_slots)
102 {
103 	struct dlm_rcom *rc = ls->ls_recover_buf;
104 	struct dlm_member *memb;
105 	int error = 0, delay;
106 
107 	list_for_each_entry(memb, &ls->ls_nodes, list) {
108 		delay = 0;
109 		for (;;) {
110 			if (dlm_recovery_stopped(ls)) {
111 				error = -EINTR;
112 				goto out;
113 			}
114 
115 			error = dlm_rcom_status(ls, memb->nodeid, 0);
116 			if (error)
117 				goto out;
118 
119 			if (save_slots)
120 				dlm_slot_save(ls, rc, memb);
121 
122 			if (rc->rc_result & wait_status)
123 				break;
124 			if (delay < 1000)
125 				delay += 20;
126 			msleep(delay);
127 		}
128 	}
129  out:
130 	return error;
131 }
132 
133 static int wait_status_low(struct dlm_ls *ls, uint32_t wait_status,
134 			   uint32_t status_flags)
135 {
136 	struct dlm_rcom *rc = ls->ls_recover_buf;
137 	int error = 0, delay = 0, nodeid = ls->ls_low_nodeid;
138 
139 	for (;;) {
140 		if (dlm_recovery_stopped(ls)) {
141 			error = -EINTR;
142 			goto out;
143 		}
144 
145 		error = dlm_rcom_status(ls, nodeid, status_flags);
146 		if (error)
147 			break;
148 
149 		if (rc->rc_result & wait_status)
150 			break;
151 		if (delay < 1000)
152 			delay += 20;
153 		msleep(delay);
154 	}
155  out:
156 	return error;
157 }
158 
159 static int wait_status(struct dlm_ls *ls, uint32_t status)
160 {
161 	uint32_t status_all = status << 1;
162 	int error;
163 
164 	if (ls->ls_low_nodeid == dlm_our_nodeid()) {
165 		error = wait_status_all(ls, status, 0);
166 		if (!error)
167 			dlm_set_recover_status(ls, status_all);
168 	} else
169 		error = wait_status_low(ls, status_all, 0);
170 
171 	return error;
172 }
173 
174 int dlm_recover_members_wait(struct dlm_ls *ls)
175 {
176 	struct dlm_member *memb;
177 	struct dlm_slot *slots;
178 	int num_slots, slots_size;
179 	int error, rv;
180 	uint32_t gen;
181 
182 	list_for_each_entry(memb, &ls->ls_nodes, list) {
183 		memb->slot = -1;
184 		memb->generation = 0;
185 	}
186 
187 	if (ls->ls_low_nodeid == dlm_our_nodeid()) {
188 		error = wait_status_all(ls, DLM_RS_NODES, 1);
189 		if (error)
190 			goto out;
191 
192 		/* slots array is sparse, slots_size may be > num_slots */
193 
194 		rv = dlm_slots_assign(ls, &num_slots, &slots_size, &slots, &gen);
195 		if (!rv) {
196 			spin_lock(&ls->ls_recover_lock);
197 			_set_recover_status(ls, DLM_RS_NODES_ALL);
198 			ls->ls_num_slots = num_slots;
199 			ls->ls_slots_size = slots_size;
200 			ls->ls_slots = slots;
201 			ls->ls_generation = gen;
202 			spin_unlock(&ls->ls_recover_lock);
203 		} else {
204 			dlm_set_recover_status(ls, DLM_RS_NODES_ALL);
205 		}
206 	} else {
207 		error = wait_status_low(ls, DLM_RS_NODES_ALL, DLM_RSF_NEED_SLOTS);
208 		if (error)
209 			goto out;
210 
211 		dlm_slots_copy_in(ls);
212 	}
213  out:
214 	return error;
215 }
216 
217 int dlm_recover_directory_wait(struct dlm_ls *ls)
218 {
219 	return wait_status(ls, DLM_RS_DIR);
220 }
221 
222 int dlm_recover_locks_wait(struct dlm_ls *ls)
223 {
224 	return wait_status(ls, DLM_RS_LOCKS);
225 }
226 
227 int dlm_recover_done_wait(struct dlm_ls *ls)
228 {
229 	return wait_status(ls, DLM_RS_DONE);
230 }
231 
232 /*
233  * The recover_list contains all the rsb's for which we've requested the new
234  * master nodeid.  As replies are returned from the resource directories the
235  * rsb's are removed from the list.  When the list is empty we're done.
236  *
237  * The recover_list is later similarly used for all rsb's for which we've sent
238  * new lkb's and need to receive new corresponding lkid's.
239  *
240  * We use the address of the rsb struct as a simple local identifier for the
241  * rsb so we can match an rcom reply with the rsb it was sent for.
242  */
243 
244 static int recover_list_empty(struct dlm_ls *ls)
245 {
246 	int empty;
247 
248 	spin_lock(&ls->ls_recover_list_lock);
249 	empty = list_empty(&ls->ls_recover_list);
250 	spin_unlock(&ls->ls_recover_list_lock);
251 
252 	return empty;
253 }
254 
255 static void recover_list_add(struct dlm_rsb *r)
256 {
257 	struct dlm_ls *ls = r->res_ls;
258 
259 	spin_lock(&ls->ls_recover_list_lock);
260 	if (list_empty(&r->res_recover_list)) {
261 		list_add_tail(&r->res_recover_list, &ls->ls_recover_list);
262 		ls->ls_recover_list_count++;
263 		dlm_hold_rsb(r);
264 	}
265 	spin_unlock(&ls->ls_recover_list_lock);
266 }
267 
268 static void recover_list_del(struct dlm_rsb *r)
269 {
270 	struct dlm_ls *ls = r->res_ls;
271 
272 	spin_lock(&ls->ls_recover_list_lock);
273 	list_del_init(&r->res_recover_list);
274 	ls->ls_recover_list_count--;
275 	spin_unlock(&ls->ls_recover_list_lock);
276 
277 	dlm_put_rsb(r);
278 }
279 
280 static void recover_list_clear(struct dlm_ls *ls)
281 {
282 	struct dlm_rsb *r, *s;
283 
284 	spin_lock(&ls->ls_recover_list_lock);
285 	list_for_each_entry_safe(r, s, &ls->ls_recover_list, res_recover_list) {
286 		list_del_init(&r->res_recover_list);
287 		r->res_recover_locks_count = 0;
288 		dlm_put_rsb(r);
289 		ls->ls_recover_list_count--;
290 	}
291 
292 	if (ls->ls_recover_list_count != 0) {
293 		log_error(ls, "warning: recover_list_count %d",
294 			  ls->ls_recover_list_count);
295 		ls->ls_recover_list_count = 0;
296 	}
297 	spin_unlock(&ls->ls_recover_list_lock);
298 }
299 
300 static int recover_idr_empty(struct dlm_ls *ls)
301 {
302 	int empty = 1;
303 
304 	spin_lock(&ls->ls_recover_idr_lock);
305 	if (ls->ls_recover_list_count)
306 		empty = 0;
307 	spin_unlock(&ls->ls_recover_idr_lock);
308 
309 	return empty;
310 }
311 
312 static int recover_idr_add(struct dlm_rsb *r)
313 {
314 	struct dlm_ls *ls = r->res_ls;
315 	int rv, id;
316 
317 	rv = idr_pre_get(&ls->ls_recover_idr, GFP_NOFS);
318 	if (!rv)
319 		return -ENOMEM;
320 
321 	spin_lock(&ls->ls_recover_idr_lock);
322 	if (r->res_id) {
323 		spin_unlock(&ls->ls_recover_idr_lock);
324 		return -1;
325 	}
326 	rv = idr_get_new_above(&ls->ls_recover_idr, r, 1, &id);
327 	if (rv) {
328 		spin_unlock(&ls->ls_recover_idr_lock);
329 		return rv;
330 	}
331 	r->res_id = id;
332 	ls->ls_recover_list_count++;
333 	dlm_hold_rsb(r);
334 	spin_unlock(&ls->ls_recover_idr_lock);
335 	return 0;
336 }
337 
338 static void recover_idr_del(struct dlm_rsb *r)
339 {
340 	struct dlm_ls *ls = r->res_ls;
341 
342 	spin_lock(&ls->ls_recover_idr_lock);
343 	idr_remove(&ls->ls_recover_idr, r->res_id);
344 	r->res_id = 0;
345 	ls->ls_recover_list_count--;
346 	spin_unlock(&ls->ls_recover_idr_lock);
347 
348 	dlm_put_rsb(r);
349 }
350 
351 static struct dlm_rsb *recover_idr_find(struct dlm_ls *ls, uint64_t id)
352 {
353 	struct dlm_rsb *r;
354 
355 	spin_lock(&ls->ls_recover_idr_lock);
356 	r = idr_find(&ls->ls_recover_idr, (int)id);
357 	spin_unlock(&ls->ls_recover_idr_lock);
358 	return r;
359 }
360 
361 static int recover_idr_clear_rsb(int id, void *p, void *data)
362 {
363 	struct dlm_ls *ls = data;
364 	struct dlm_rsb *r = p;
365 
366 	r->res_id = 0;
367 	r->res_recover_locks_count = 0;
368 	ls->ls_recover_list_count--;
369 
370 	dlm_put_rsb(r);
371 	return 0;
372 }
373 
374 static void recover_idr_clear(struct dlm_ls *ls)
375 {
376 	spin_lock(&ls->ls_recover_idr_lock);
377 	idr_for_each(&ls->ls_recover_idr, recover_idr_clear_rsb, ls);
378 	idr_remove_all(&ls->ls_recover_idr);
379 
380 	if (ls->ls_recover_list_count != 0) {
381 		log_error(ls, "warning: recover_list_count %d",
382 			  ls->ls_recover_list_count);
383 		ls->ls_recover_list_count = 0;
384 	}
385 	spin_unlock(&ls->ls_recover_idr_lock);
386 }
387 
388 
389 /* Master recovery: find new master node for rsb's that were
390    mastered on nodes that have been removed.
391 
392    dlm_recover_masters
393    recover_master
394    dlm_send_rcom_lookup            ->  receive_rcom_lookup
395                                        dlm_dir_lookup
396    receive_rcom_lookup_reply       <-
397    dlm_recover_master_reply
398    set_new_master
399    set_master_lkbs
400    set_lock_master
401 */
402 
403 /*
404  * Set the lock master for all LKBs in a lock queue
405  * If we are the new master of the rsb, we may have received new
406  * MSTCPY locks from other nodes already which we need to ignore
407  * when setting the new nodeid.
408  */
409 
410 static void set_lock_master(struct list_head *queue, int nodeid)
411 {
412 	struct dlm_lkb *lkb;
413 
414 	list_for_each_entry(lkb, queue, lkb_statequeue) {
415 		if (!(lkb->lkb_flags & DLM_IFL_MSTCPY)) {
416 			lkb->lkb_nodeid = nodeid;
417 			lkb->lkb_remid = 0;
418 		}
419 	}
420 }
421 
422 static void set_master_lkbs(struct dlm_rsb *r)
423 {
424 	set_lock_master(&r->res_grantqueue, r->res_nodeid);
425 	set_lock_master(&r->res_convertqueue, r->res_nodeid);
426 	set_lock_master(&r->res_waitqueue, r->res_nodeid);
427 }
428 
429 /*
430  * Propagate the new master nodeid to locks
431  * The NEW_MASTER flag tells dlm_recover_locks() which rsb's to consider.
432  * The NEW_MASTER2 flag tells recover_lvb() and recover_grant() which
433  * rsb's to consider.
434  */
435 
436 static void set_new_master(struct dlm_rsb *r)
437 {
438 	set_master_lkbs(r);
439 	rsb_set_flag(r, RSB_NEW_MASTER);
440 	rsb_set_flag(r, RSB_NEW_MASTER2);
441 }
442 
443 /*
444  * We do async lookups on rsb's that need new masters.  The rsb's
445  * waiting for a lookup reply are kept on the recover_list.
446  *
447  * Another node recovering the master may have sent us a rcom lookup,
448  * and our dlm_master_lookup() set it as the new master, along with
449  * NEW_MASTER so that we'll recover it here (this implies dir_nodeid
450  * equals our_nodeid below).
451  */
452 
453 static int recover_master(struct dlm_rsb *r, unsigned int *count)
454 {
455 	struct dlm_ls *ls = r->res_ls;
456 	int our_nodeid, dir_nodeid;
457 	int is_removed = 0;
458 	int error;
459 
460 	if (is_master(r))
461 		return 0;
462 
463 	is_removed = dlm_is_removed(ls, r->res_nodeid);
464 
465 	if (!is_removed && !rsb_flag(r, RSB_NEW_MASTER))
466 		return 0;
467 
468 	our_nodeid = dlm_our_nodeid();
469 	dir_nodeid = dlm_dir_nodeid(r);
470 
471 	if (dir_nodeid == our_nodeid) {
472 		if (is_removed) {
473 			r->res_master_nodeid = our_nodeid;
474 			r->res_nodeid = 0;
475 		}
476 
477 		/* set master of lkbs to ourself when is_removed, or to
478 		   another new master which we set along with NEW_MASTER
479 		   in dlm_master_lookup */
480 		set_new_master(r);
481 		error = 0;
482 	} else {
483 		recover_idr_add(r);
484 		error = dlm_send_rcom_lookup(r, dir_nodeid);
485 	}
486 
487 	(*count)++;
488 	return error;
489 }
490 
491 /*
492  * All MSTCPY locks are purged and rebuilt, even if the master stayed the same.
493  * This is necessary because recovery can be started, aborted and restarted,
494  * causing the master nodeid to briefly change during the aborted recovery, and
495  * change back to the original value in the second recovery.  The MSTCPY locks
496  * may or may not have been purged during the aborted recovery.  Another node
497  * with an outstanding request in waiters list and a request reply saved in the
498  * requestqueue, cannot know whether it should ignore the reply and resend the
499  * request, or accept the reply and complete the request.  It must do the
500  * former if the remote node purged MSTCPY locks, and it must do the later if
501  * the remote node did not.  This is solved by always purging MSTCPY locks, in
502  * which case, the request reply would always be ignored and the request
503  * resent.
504  */
505 
506 static int recover_master_static(struct dlm_rsb *r, unsigned int *count)
507 {
508 	int dir_nodeid = dlm_dir_nodeid(r);
509 	int new_master = dir_nodeid;
510 
511 	if (dir_nodeid == dlm_our_nodeid())
512 		new_master = 0;
513 
514 	dlm_purge_mstcpy_locks(r);
515 	r->res_master_nodeid = dir_nodeid;
516 	r->res_nodeid = new_master;
517 	set_new_master(r);
518 	(*count)++;
519 	return 0;
520 }
521 
522 /*
523  * Go through local root resources and for each rsb which has a master which
524  * has departed, get the new master nodeid from the directory.  The dir will
525  * assign mastery to the first node to look up the new master.  That means
526  * we'll discover in this lookup if we're the new master of any rsb's.
527  *
528  * We fire off all the dir lookup requests individually and asynchronously to
529  * the correct dir node.
530  */
531 
532 int dlm_recover_masters(struct dlm_ls *ls)
533 {
534 	struct dlm_rsb *r;
535 	unsigned int total = 0;
536 	unsigned int count = 0;
537 	int nodir = dlm_no_directory(ls);
538 	int error;
539 
540 	log_debug(ls, "dlm_recover_masters");
541 
542 	down_read(&ls->ls_root_sem);
543 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
544 		if (dlm_recovery_stopped(ls)) {
545 			up_read(&ls->ls_root_sem);
546 			error = -EINTR;
547 			goto out;
548 		}
549 
550 		lock_rsb(r);
551 		if (nodir)
552 			error = recover_master_static(r, &count);
553 		else
554 			error = recover_master(r, &count);
555 		unlock_rsb(r);
556 		cond_resched();
557 		total++;
558 
559 		if (error) {
560 			up_read(&ls->ls_root_sem);
561 			goto out;
562 		}
563 	}
564 	up_read(&ls->ls_root_sem);
565 
566 	log_debug(ls, "dlm_recover_masters %u of %u", count, total);
567 
568 	error = dlm_wait_function(ls, &recover_idr_empty);
569  out:
570 	if (error)
571 		recover_idr_clear(ls);
572 	return error;
573 }
574 
575 int dlm_recover_master_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
576 {
577 	struct dlm_rsb *r;
578 	int ret_nodeid, new_master;
579 
580 	r = recover_idr_find(ls, rc->rc_id);
581 	if (!r) {
582 		log_error(ls, "dlm_recover_master_reply no id %llx",
583 			  (unsigned long long)rc->rc_id);
584 		goto out;
585 	}
586 
587 	ret_nodeid = rc->rc_result;
588 
589 	if (ret_nodeid == dlm_our_nodeid())
590 		new_master = 0;
591 	else
592 		new_master = ret_nodeid;
593 
594 	lock_rsb(r);
595 	r->res_master_nodeid = ret_nodeid;
596 	r->res_nodeid = new_master;
597 	set_new_master(r);
598 	unlock_rsb(r);
599 	recover_idr_del(r);
600 
601 	if (recover_idr_empty(ls))
602 		wake_up(&ls->ls_wait_general);
603  out:
604 	return 0;
605 }
606 
607 
608 /* Lock recovery: rebuild the process-copy locks we hold on a
609    remastered rsb on the new rsb master.
610 
611    dlm_recover_locks
612    recover_locks
613    recover_locks_queue
614    dlm_send_rcom_lock              ->  receive_rcom_lock
615                                        dlm_recover_master_copy
616    receive_rcom_lock_reply         <-
617    dlm_recover_process_copy
618 */
619 
620 
621 /*
622  * keep a count of the number of lkb's we send to the new master; when we get
623  * an equal number of replies then recovery for the rsb is done
624  */
625 
626 static int recover_locks_queue(struct dlm_rsb *r, struct list_head *head)
627 {
628 	struct dlm_lkb *lkb;
629 	int error = 0;
630 
631 	list_for_each_entry(lkb, head, lkb_statequeue) {
632 	   	error = dlm_send_rcom_lock(r, lkb);
633 		if (error)
634 			break;
635 		r->res_recover_locks_count++;
636 	}
637 
638 	return error;
639 }
640 
641 static int recover_locks(struct dlm_rsb *r)
642 {
643 	int error = 0;
644 
645 	lock_rsb(r);
646 
647 	DLM_ASSERT(!r->res_recover_locks_count, dlm_dump_rsb(r););
648 
649 	error = recover_locks_queue(r, &r->res_grantqueue);
650 	if (error)
651 		goto out;
652 	error = recover_locks_queue(r, &r->res_convertqueue);
653 	if (error)
654 		goto out;
655 	error = recover_locks_queue(r, &r->res_waitqueue);
656 	if (error)
657 		goto out;
658 
659 	if (r->res_recover_locks_count)
660 		recover_list_add(r);
661 	else
662 		rsb_clear_flag(r, RSB_NEW_MASTER);
663  out:
664 	unlock_rsb(r);
665 	return error;
666 }
667 
668 int dlm_recover_locks(struct dlm_ls *ls)
669 {
670 	struct dlm_rsb *r;
671 	int error, count = 0;
672 
673 	down_read(&ls->ls_root_sem);
674 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
675 		if (is_master(r)) {
676 			rsb_clear_flag(r, RSB_NEW_MASTER);
677 			continue;
678 		}
679 
680 		if (!rsb_flag(r, RSB_NEW_MASTER))
681 			continue;
682 
683 		if (dlm_recovery_stopped(ls)) {
684 			error = -EINTR;
685 			up_read(&ls->ls_root_sem);
686 			goto out;
687 		}
688 
689 		error = recover_locks(r);
690 		if (error) {
691 			up_read(&ls->ls_root_sem);
692 			goto out;
693 		}
694 
695 		count += r->res_recover_locks_count;
696 	}
697 	up_read(&ls->ls_root_sem);
698 
699 	log_debug(ls, "dlm_recover_locks %d out", count);
700 
701 	error = dlm_wait_function(ls, &recover_list_empty);
702  out:
703 	if (error)
704 		recover_list_clear(ls);
705 	return error;
706 }
707 
708 void dlm_recovered_lock(struct dlm_rsb *r)
709 {
710 	DLM_ASSERT(rsb_flag(r, RSB_NEW_MASTER), dlm_dump_rsb(r););
711 
712 	r->res_recover_locks_count--;
713 	if (!r->res_recover_locks_count) {
714 		rsb_clear_flag(r, RSB_NEW_MASTER);
715 		recover_list_del(r);
716 	}
717 
718 	if (recover_list_empty(r->res_ls))
719 		wake_up(&r->res_ls->ls_wait_general);
720 }
721 
722 /*
723  * The lvb needs to be recovered on all master rsb's.  This includes setting
724  * the VALNOTVALID flag if necessary, and determining the correct lvb contents
725  * based on the lvb's of the locks held on the rsb.
726  *
727  * RSB_VALNOTVALID is set if there are only NL/CR locks on the rsb.  If it
728  * was already set prior to recovery, it's not cleared, regardless of locks.
729  *
730  * The LVB contents are only considered for changing when this is a new master
731  * of the rsb (NEW_MASTER2).  Then, the rsb's lvb is taken from any lkb with
732  * mode > CR.  If no lkb's exist with mode above CR, the lvb contents are taken
733  * from the lkb with the largest lvb sequence number.
734  */
735 
736 static void recover_lvb(struct dlm_rsb *r)
737 {
738 	struct dlm_lkb *lkb, *high_lkb = NULL;
739 	uint32_t high_seq = 0;
740 	int lock_lvb_exists = 0;
741 	int big_lock_exists = 0;
742 	int lvblen = r->res_ls->ls_lvblen;
743 
744 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
745 		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
746 			continue;
747 
748 		lock_lvb_exists = 1;
749 
750 		if (lkb->lkb_grmode > DLM_LOCK_CR) {
751 			big_lock_exists = 1;
752 			goto setflag;
753 		}
754 
755 		if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
756 			high_lkb = lkb;
757 			high_seq = lkb->lkb_lvbseq;
758 		}
759 	}
760 
761 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
762 		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
763 			continue;
764 
765 		lock_lvb_exists = 1;
766 
767 		if (lkb->lkb_grmode > DLM_LOCK_CR) {
768 			big_lock_exists = 1;
769 			goto setflag;
770 		}
771 
772 		if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
773 			high_lkb = lkb;
774 			high_seq = lkb->lkb_lvbseq;
775 		}
776 	}
777 
778  setflag:
779 	if (!lock_lvb_exists)
780 		goto out;
781 
782 	if (!big_lock_exists)
783 		rsb_set_flag(r, RSB_VALNOTVALID);
784 
785 	/* don't mess with the lvb unless we're the new master */
786 	if (!rsb_flag(r, RSB_NEW_MASTER2))
787 		goto out;
788 
789 	if (!r->res_lvbptr) {
790 		r->res_lvbptr = dlm_allocate_lvb(r->res_ls);
791 		if (!r->res_lvbptr)
792 			goto out;
793 	}
794 
795 	if (big_lock_exists) {
796 		r->res_lvbseq = lkb->lkb_lvbseq;
797 		memcpy(r->res_lvbptr, lkb->lkb_lvbptr, lvblen);
798 	} else if (high_lkb) {
799 		r->res_lvbseq = high_lkb->lkb_lvbseq;
800 		memcpy(r->res_lvbptr, high_lkb->lkb_lvbptr, lvblen);
801 	} else {
802 		r->res_lvbseq = 0;
803 		memset(r->res_lvbptr, 0, lvblen);
804 	}
805  out:
806 	return;
807 }
808 
809 /* All master rsb's flagged RECOVER_CONVERT need to be looked at.  The locks
810    converting PR->CW or CW->PR need to have their lkb_grmode set. */
811 
812 static void recover_conversion(struct dlm_rsb *r)
813 {
814 	struct dlm_lkb *lkb;
815 	int grmode = -1;
816 
817 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
818 		if (lkb->lkb_grmode == DLM_LOCK_PR ||
819 		    lkb->lkb_grmode == DLM_LOCK_CW) {
820 			grmode = lkb->lkb_grmode;
821 			break;
822 		}
823 	}
824 
825 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
826 		if (lkb->lkb_grmode != DLM_LOCK_IV)
827 			continue;
828 		if (grmode == -1)
829 			lkb->lkb_grmode = lkb->lkb_rqmode;
830 		else
831 			lkb->lkb_grmode = grmode;
832 	}
833 }
834 
835 /* We've become the new master for this rsb and waiting/converting locks may
836    need to be granted in dlm_recover_grant() due to locks that may have
837    existed from a removed node. */
838 
839 static void recover_grant(struct dlm_rsb *r)
840 {
841 	if (!list_empty(&r->res_waitqueue) || !list_empty(&r->res_convertqueue))
842 		rsb_set_flag(r, RSB_RECOVER_GRANT);
843 }
844 
845 void dlm_recover_rsbs(struct dlm_ls *ls)
846 {
847 	struct dlm_rsb *r;
848 	unsigned int count = 0;
849 
850 	down_read(&ls->ls_root_sem);
851 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
852 		lock_rsb(r);
853 		if (is_master(r)) {
854 			if (rsb_flag(r, RSB_RECOVER_CONVERT))
855 				recover_conversion(r);
856 			if (rsb_flag(r, RSB_NEW_MASTER2))
857 				recover_grant(r);
858 			recover_lvb(r);
859 			count++;
860 		}
861 		rsb_clear_flag(r, RSB_RECOVER_CONVERT);
862 		rsb_clear_flag(r, RSB_NEW_MASTER2);
863 		unlock_rsb(r);
864 	}
865 	up_read(&ls->ls_root_sem);
866 
867 	if (count)
868 		log_debug(ls, "dlm_recover_rsbs %d done", count);
869 }
870 
871 /* Create a single list of all root rsb's to be used during recovery */
872 
873 int dlm_create_root_list(struct dlm_ls *ls)
874 {
875 	struct rb_node *n;
876 	struct dlm_rsb *r;
877 	int i, error = 0;
878 
879 	down_write(&ls->ls_root_sem);
880 	if (!list_empty(&ls->ls_root_list)) {
881 		log_error(ls, "root list not empty");
882 		error = -EINVAL;
883 		goto out;
884 	}
885 
886 	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
887 		spin_lock(&ls->ls_rsbtbl[i].lock);
888 		for (n = rb_first(&ls->ls_rsbtbl[i].keep); n; n = rb_next(n)) {
889 			r = rb_entry(n, struct dlm_rsb, res_hashnode);
890 			list_add(&r->res_root_list, &ls->ls_root_list);
891 			dlm_hold_rsb(r);
892 		}
893 
894 		if (!RB_EMPTY_ROOT(&ls->ls_rsbtbl[i].toss))
895 			log_error(ls, "dlm_create_root_list toss not empty");
896 		spin_unlock(&ls->ls_rsbtbl[i].lock);
897 	}
898  out:
899 	up_write(&ls->ls_root_sem);
900 	return error;
901 }
902 
903 void dlm_release_root_list(struct dlm_ls *ls)
904 {
905 	struct dlm_rsb *r, *safe;
906 
907 	down_write(&ls->ls_root_sem);
908 	list_for_each_entry_safe(r, safe, &ls->ls_root_list, res_root_list) {
909 		list_del_init(&r->res_root_list);
910 		dlm_put_rsb(r);
911 	}
912 	up_write(&ls->ls_root_sem);
913 }
914 
915 void dlm_clear_toss(struct dlm_ls *ls)
916 {
917 	struct rb_node *n, *next;
918 	struct dlm_rsb *r;
919 	unsigned int count = 0;
920 	int i;
921 
922 	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
923 		spin_lock(&ls->ls_rsbtbl[i].lock);
924 		for (n = rb_first(&ls->ls_rsbtbl[i].toss); n; n = next) {
925 			next = rb_next(n);
926 			r = rb_entry(n, struct dlm_rsb, res_hashnode);
927 			rb_erase(n, &ls->ls_rsbtbl[i].toss);
928 			dlm_free_rsb(r);
929 			count++;
930 		}
931 		spin_unlock(&ls->ls_rsbtbl[i].lock);
932 	}
933 
934 	if (count)
935 		log_debug(ls, "dlm_clear_toss %u done", count);
936 }
937 
938