aboutsummaryrefslogblamecommitdiffstats
path: root/fs/ocfs2/dlm/dlmrecovery.c
blob: f9ce864966ec60a90ce8c25badca9028ebccce74 (plain) (tree)
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840








































                                                                    
                        
























































































































































































































                                                                              




















                                                                








































                                                                  
                













































                                                                             





                                                                    
                                                             























                                                                             


                                                                  

                                                                    

                                                                            







































































































                                                                                   
                                                                             






                                                                            












                                                                                     
































































































































































































                                                                                       

















                                                                                 


                                                    









































































                                                                                
                                                                                   

                                                     





                                                                             


                                                                                  
































                                                                            
                              



                                                                              

                                                                     
                                                            













                                                                         
                                 

                 




















































































































































































































































































































































































                                                                                        
                                                                      
































































































































































































































































































































































































































































































































































































                                                                                     
                              






















                                                                                

                                                                             
                                                                    













                                                                                 
                                         
                                                




















































































                                                                            
                                          

                                                                    





















                                                                   











                                                               







                                                                     
        




                                                                                


                                                                


                                                                   








                                                                    























                                                                                    









                                                                 



                                                                            



                                                                                          






                                                                         
                                                                       




                                                                              












                                                                               
                                 















                                                                               





































                                                                          
      







                                                                            






                                                                               

                                                      

                                                                          










                                                                             



                                                                      





















                                                                      









                                                                          

                                                           


                                                                       



                                                          
                                                                       

                                                                 





                                                                    

























































































                                                                              
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmrecovery.c
 *
 * recovery stuff
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */


#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/timer.h>
#include <linux/kthread.h>
#include <linux/delay.h>


#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"

#include "dlmapi.h"
#include "dlmcommon.h"
#include "dlmdomain.h"

#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_RECOVERY)
#include "cluster/masklog.h"

static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node);

static int dlm_recovery_thread(void *data);
void dlm_complete_recovery_thread(struct dlm_ctxt *dlm);
int dlm_launch_recovery_thread(struct dlm_ctxt *dlm);
static void dlm_kick_recovery_thread(struct dlm_ctxt *dlm);
static int dlm_do_recovery(struct dlm_ctxt *dlm);

static int dlm_pick_recovery_master(struct dlm_ctxt *dlm);
static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node);
static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node);
static int dlm_request_all_locks(struct dlm_ctxt *dlm,
				 u8 request_from, u8 dead_node);
static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node);

static inline int dlm_num_locks_in_lockres(struct dlm_lock_resource *res);
static void dlm_init_migratable_lockres(struct dlm_migratable_lockres *mres,
					const char *lockname, int namelen,
					int total_locks, u64 cookie,
					u8 flags, u8 master);
static int dlm_send_mig_lockres_msg(struct dlm_ctxt *dlm,
				    struct dlm_migratable_lockres *mres,
				    u8 send_to,
				    struct dlm_lock_resource *res,
				    int total_locks);
static int dlm_lockres_master_requery(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res,
				      u8 *real_master);
static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
				     struct dlm_lock_resource *res,
				     struct dlm_migratable_lockres *mres);
static int dlm_do_master_requery(struct dlm_ctxt *dlm,
				 struct dlm_lock_resource *res,
				 u8 nodenum, u8 *real_master);
static int dlm_send_finalize_reco_message(struct dlm_ctxt *dlm);
static int dlm_send_all_done_msg(struct dlm_ctxt *dlm,
				 u8 dead_node, u8 send_to);
static int dlm_send_begin_reco_message(struct dlm_ctxt *dlm, u8 dead_node);
static void dlm_move_reco_locks_to_list(struct dlm_ctxt *dlm,
					struct list_head *list, u8 dead_node);
static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
					      u8 dead_node, u8 new_master);
static void dlm_reco_ast(void *astdata);
static void dlm_reco_bast(void *astdata, int blocked_type);
static void dlm_reco_unlock_ast(void *astdata, enum dlm_status st);
static void dlm_request_all_locks_worker(struct dlm_work_item *item,
					 void *data);
static void dlm_mig_lockres_worker(struct dlm_work_item *item, void *data);

static u64 dlm_get_next_mig_cookie(void);

static spinlock_t dlm_reco_state_lock = SPIN_LOCK_UNLOCKED;
static spinlock_t dlm_mig_cookie_lock = SPIN_LOCK_UNLOCKED;
static u64 dlm_mig_cookie = 1;

static u64 dlm_get_next_mig_cookie(void)
{
	u64 c;
	spin_lock(&dlm_mig_cookie_lock);
	c = dlm_mig_cookie;
	if (dlm_mig_cookie == (~0ULL))
		dlm_mig_cookie = 1;
	else
		dlm_mig_cookie++;
	spin_unlock(&dlm_mig_cookie_lock);
	return c;
}

static inline void dlm_reset_recovery(struct dlm_ctxt *dlm)
{
	spin_lock(&dlm->spinlock);
	clear_bit(dlm->reco.dead_node, dlm->recovery_map);
	dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
	dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
	spin_unlock(&dlm->spinlock);
}

/* Worker function used during recovery. */
void dlm_dispatch_work(void *data)
{
	struct dlm_ctxt *dlm = (struct dlm_ctxt *)data;
	LIST_HEAD(tmp_list);
	struct list_head *iter, *iter2;
	struct dlm_work_item *item;
	dlm_workfunc_t *workfunc;

	spin_lock(&dlm->work_lock);
	list_splice_init(&dlm->work_list, &tmp_list);
	spin_unlock(&dlm->work_lock);

	list_for_each_safe(iter, iter2, &tmp_list) {
		item = list_entry(iter, struct dlm_work_item, list);
		workfunc = item->func;
		list_del_init(&item->list);

		/* already have ref on dlm to avoid having
		 * it disappear.  just double-check. */
		BUG_ON(item->dlm != dlm);

		/* this is allowed to sleep and
		 * call network stuff */
		workfunc(item, item->data);

		dlm_put(dlm);
		kfree(item);
	}
}

/*
 * RECOVERY THREAD
 */

static void dlm_kick_recovery_thread(struct dlm_ctxt *dlm)
{
	/* wake the recovery thread
	 * this will wake the reco thread in one of three places
	 * 1) sleeping with no recovery happening
	 * 2) sleeping with recovery mastered elsewhere
	 * 3) recovery mastered here, waiting on reco data */

	wake_up(&dlm->dlm_reco_thread_wq);
}

/* Launch the recovery thread */
int dlm_launch_recovery_thread(struct dlm_ctxt *dlm)
{
	mlog(0, "starting dlm recovery thread...\n");

	dlm->dlm_reco_thread_task = kthread_run(dlm_recovery_thread, dlm,
						"dlm_reco_thread");
	if (IS_ERR(dlm->dlm_reco_thread_task)) {
		mlog_errno(PTR_ERR(dlm->dlm_reco_thread_task));
		dlm->dlm_reco_thread_task = NULL;
		return -EINVAL;
	}

	return 0;
}

void dlm_complete_recovery_thread(struct dlm_ctxt *dlm)
{
	if (dlm->dlm_reco_thread_task) {
		mlog(0, "waiting for dlm recovery thread to exit\n");
		kthread_stop(dlm->dlm_reco_thread_task);
		dlm->dlm_reco_thread_task = NULL;
	}
}



/*
 * this is lame, but here's how recovery works...
 * 1) all recovery threads cluster wide will work on recovering
 *    ONE node at a time
 * 2) negotiate who will take over all the locks for the dead node.
 *    thats right... ALL the locks.
 * 3) once a new master is chosen, everyone scans all locks
 *    and moves aside those mastered by the dead guy
 * 4) each of these locks should be locked until recovery is done
 * 5) the new master collects up all of secondary lock queue info
 *    one lock at a time, forcing each node to communicate back
 *    before continuing
 * 6) each secondary lock queue responds with the full known lock info
 * 7) once the new master has run all its locks, it sends a ALLDONE!
 *    message to everyone
 * 8) upon receiving this message, the secondary queue node unlocks
 *    and responds to the ALLDONE
 * 9) once the new master gets responses from everyone, he unlocks
 *    everything and recovery for this dead node is done
 *10) go back to 2) while there are still dead nodes
 *
 */


#define DLM_RECO_THREAD_TIMEOUT_MS (5 * 1000)

static int dlm_recovery_thread(void *data)
{
	int status;
	struct dlm_ctxt *dlm = data;
	unsigned long timeout = msecs_to_jiffies(DLM_RECO_THREAD_TIMEOUT_MS);

	mlog(0, "dlm thread running for %s...\n", dlm->name);

	while (!kthread_should_stop()) {
		if (dlm_joined(dlm)) {
			status = dlm_do_recovery(dlm);
			if (status == -EAGAIN) {
				/* do not sleep, recheck immediately. */
				continue;
			}
			if (status < 0)
				mlog_errno(status);
		}

		wait_event_interruptible_timeout(dlm->dlm_reco_thread_wq,
						 kthread_should_stop(),
						 timeout);
	}

	mlog(0, "quitting DLM recovery thread\n");
	return 0;
}

/* returns true when the recovery master has contacted us */
static int dlm_reco_master_ready(struct dlm_ctxt *dlm)
{
	int ready;
	spin_lock(&dlm->spinlock);
	ready = (dlm->reco.new_master != O2NM_INVALID_NODE_NUM);
	spin_unlock(&dlm->spinlock);
	return ready;
}

/* returns true if node is no longer in the domain
 * could be dead or just not joined */
int dlm_is_node_dead(struct dlm_ctxt *dlm, u8 node)
{
	int dead;
	spin_lock(&dlm->spinlock);
	dead = test_bit(node, dlm->domain_map);
	spin_unlock(&dlm->spinlock);
	return dead;
}

/* callers of the top-level api calls (dlmlock/dlmunlock) should
 * block on the dlm->reco.event when recovery is in progress.
 * the dlm recovery thread will set this state when it begins
 * recovering a dead node (as the new master or not) and clear
 * the state and wake as soon as all affected lock resources have
 * been marked with the RECOVERY flag */
static int dlm_in_recovery(struct dlm_ctxt *dlm)
{
	int in_recovery;
	spin_lock(&dlm->spinlock);
	in_recovery = !!(dlm->reco.state & DLM_RECO_STATE_ACTIVE);
	spin_unlock(&dlm->spinlock);
	return in_recovery;
}


void dlm_wait_for_recovery(struct dlm_ctxt *dlm)
{
	wait_event(dlm->reco.event, !dlm_in_recovery(dlm));
}

static void dlm_begin_recovery(struct dlm_ctxt *dlm)
{
	spin_lock(&dlm->spinlock);
	BUG_ON(dlm->reco.state & DLM_RECO_STATE_ACTIVE);
	dlm->reco.state |= DLM_RECO_STATE_ACTIVE;
	spin_unlock(&dlm->spinlock);
}

static void dlm_end_recovery(struct dlm_ctxt *dlm)
{
	spin_lock(&dlm->spinlock);
	BUG_ON(!(dlm->reco.state & DLM_RECO_STATE_ACTIVE));
	dlm->reco.state &= ~DLM_RECO_STATE_ACTIVE;
	spin_unlock(&dlm->spinlock);
	wake_up(&dlm->reco.event);
}

static int dlm_do_recovery(struct dlm_ctxt *dlm)
{
	int status = 0;
	int ret;

	spin_lock(&dlm->spinlock);

	/* check to see if the new master has died */
	if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM &&
	    test_bit(dlm->reco.new_master, dlm->recovery_map)) {
		mlog(0, "new master %u died while recovering %u!\n",
		     dlm->reco.new_master, dlm->reco.dead_node);
		/* unset the new_master, leave dead_node */
		dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
	}

	/* select a target to recover */
	if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
		int bit;

		bit = find_next_bit (dlm->recovery_map, O2NM_MAX_NODES+1, 0);
		if (bit >= O2NM_MAX_NODES || bit < 0)
			dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
		else
			dlm->reco.dead_node = bit;
	} else if (!test_bit(dlm->reco.dead_node, dlm->recovery_map)) {
		/* BUG? */
		mlog(ML_ERROR, "dead_node %u no longer in recovery map!\n",
		     dlm->reco.dead_node);
		dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
	}

	if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
		// mlog(0, "nothing to recover!  sleeping now!\n");
		spin_unlock(&dlm->spinlock);
		/* return to main thread loop and sleep. */
		return 0;
	}
	mlog(0, "recovery thread found node %u in the recovery map!\n",
	     dlm->reco.dead_node);
	spin_unlock(&dlm->spinlock);

	/* take write barrier */
	/* (stops the list reshuffling thread, proxy ast handling) */
	dlm_begin_recovery(dlm);

	if (dlm->reco.new_master == dlm->node_num)
		goto master_here;

	if (dlm->reco.new_master == O2NM_INVALID_NODE_NUM) {
		/* choose a new master, returns 0 if this node
		 * is the master, -EEXIST if it's another node.
		 * this does not return until a new master is chosen
		 * or recovery completes entirely. */
		ret = dlm_pick_recovery_master(dlm);
		if (!ret) {
			/* already notified everyone.  go. */
			goto master_here;
		}
		mlog(0, "another node will master this recovery session.\n");
	}
	mlog(0, "dlm=%s, new_master=%u, this node=%u, dead_node=%u\n",
	     dlm->name, dlm->reco.new_master,
	     dlm->node_num, dlm->reco.dead_node);

	/* it is safe to start everything back up here
	 * because all of the dead node's lock resources
	 * have been marked as in-recovery */
	dlm_end_recovery(dlm);

	/* sleep out in main dlm_recovery_thread loop. */
	return 0;

master_here:
	mlog(0, "mastering recovery of %s:%u here(this=%u)!\n",
	     dlm->name, dlm->reco.dead_node, dlm->node_num);

	status = dlm_remaster_locks(dlm, dlm->reco.dead_node);
	if (status < 0) {
		mlog(ML_ERROR, "error %d remastering locks for node %u, "
		     "retrying.\n", status, dlm->reco.dead_node);
		/* yield a bit to allow any final network messages
		 * to get handled on remaining nodes */
		msleep(100);
	} else {
		/* success!  see if any other nodes need recovery */
		mlog(0, "DONE mastering recovery of %s:%u here(this=%u)!\n",
		     dlm->name, dlm->reco.dead_node, dlm->node_num);
		dlm_reset_recovery(dlm);
	}
	dlm_end_recovery(dlm);

	/* continue and look for another dead node */
	return -EAGAIN;
}

static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
{
	int status = 0;
	struct dlm_reco_node_data *ndata;
	struct list_head *iter;
	int all_nodes_done;
	int destroy = 0;
	int pass = 0;

	status = dlm_init_recovery_area(dlm, dead_node);
	if (status < 0)
		goto leave;

	/* safe to access the node data list without a lock, since this
	 * process is the only one to change the list */
	list_for_each(iter, &dlm->reco.node_data) {
		ndata = list_entry (iter, struct dlm_reco_node_data, list);
		BUG_ON(ndata->state != DLM_RECO_NODE_DATA_INIT);
		ndata->state = DLM_RECO_NODE_DATA_REQUESTING;

		mlog(0, "requesting lock info from node %u\n",
		     ndata->node_num);

		if (ndata->node_num == dlm->node_num) {
			ndata->state = DLM_RECO_NODE_DATA_DONE;
			continue;
		}

		status = dlm_request_all_locks(dlm, ndata->node_num, dead_node);
		if (status < 0) {
			mlog_errno(status);
			if (dlm_is_host_down(status))
				ndata->state = DLM_RECO_NODE_DATA_DEAD;
			else {
				destroy = 1;
				goto leave;
			}
		}

		switch (ndata->state) {
			case DLM_RECO_NODE_DATA_INIT:
			case DLM_RECO_NODE_DATA_FINALIZE_SENT:
			case DLM_RECO_NODE_DATA_REQUESTED:
				BUG();
				break;
			case DLM_RECO_NODE_DATA_DEAD:
				mlog(0, "node %u died after requesting "
				     "recovery info for node %u\n",
				     ndata->node_num, dead_node);
				// start all over
				destroy = 1;
				status = -EAGAIN;
				goto leave;
			case DLM_RECO_NODE_DATA_REQUESTING:
				ndata->state = DLM_RECO_NODE_DATA_REQUESTED;
				mlog(0, "now receiving recovery data from "
				     "node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
			case DLM_RECO_NODE_DATA_RECEIVING:
				mlog(0, "already receiving recovery data from "
				     "node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
			case DLM_RECO_NODE_DATA_DONE:
				mlog(0, "already DONE receiving recovery data "
				     "from node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
		}
	}

	mlog(0, "done requesting all lock info\n");

	/* nodes should be sending reco data now
	 * just need to wait */

	while (1) {
		/* check all the nodes now to see if we are
		 * done, or if anyone died */
		all_nodes_done = 1;
		spin_lock(&dlm_reco_state_lock);
		list_for_each(iter, &dlm->reco.node_data) {
			ndata = list_entry (iter, struct dlm_reco_node_data, list);

			mlog(0, "checking recovery state of node %u\n",
			     ndata->node_num);
			switch (ndata->state) {
				case DLM_RECO_NODE_DATA_INIT:
				case DLM_RECO_NODE_DATA_REQUESTING:
					mlog(ML_ERROR, "bad ndata state for "
					     "node %u: state=%d\n",
					     ndata->node_num, ndata->state);
					BUG();
					break;
				case DLM_RECO_NODE_DATA_DEAD:
					mlog(ML_NOTICE, "node %u died after "
					     "requesting recovery info for "
					     "node %u\n", ndata->node_num,
					     dead_node);
					spin_unlock(&dlm_reco_state_lock);
					// start all over
					destroy = 1;
					status = -EAGAIN;
					/* instead of spinning like crazy here,
					 * wait for the domain map to catch up
					 * with the network state.  otherwise this
					 * can be hit hundreds of times before
					 * the node is really seen as dead. */
					wait_event_timeout(dlm->dlm_reco_thread_wq,
							   dlm_is_node_dead(dlm,
								ndata->node_num),
							   msecs_to_jiffies(1000));
					mlog(0, "waited 1 sec for %u, "
					     "dead? %s\n", ndata->node_num,
					     dlm_is_node_dead(dlm, ndata->node_num) ?
					     "yes" : "no");
					goto leave;
				case DLM_RECO_NODE_DATA_RECEIVING:
				case DLM_RECO_NODE_DATA_REQUESTED:
					all_nodes_done = 0;
					break;
				case DLM_RECO_NODE_DATA_DONE:
					break;
				case DLM_RECO_NODE_DATA_FINALIZE_SENT:
					break;
			}
		}
		spin_unlock(&dlm_reco_state_lock);

		mlog(0, "pass #%d, all_nodes_done?: %s\n", ++pass,
		     all_nodes_done?"yes":"no");
		if (all_nodes_done) {
			int ret;

			/* all nodes are now in DLM_RECO_NODE_DATA_DONE state
	 		 * just send a finalize message to everyone and
	 		 * clean up */
			mlog(0, "all nodes are done! send finalize\n");
			ret = dlm_send_finalize_reco_message(dlm);
			if (ret < 0)
				mlog_errno(ret);

			spin_lock(&dlm->spinlock);
			dlm_finish_local_lockres_recovery(dlm, dead_node,
							  dlm->node_num);
			spin_unlock(&dlm->spinlock);
			mlog(0, "should be done with recovery!\n");

			mlog(0, "finishing recovery of %s at %lu, "
			     "dead=%u, this=%u, new=%u\n", dlm->name,
			     jiffies, dlm->reco.dead_node,
			     dlm->node_num, dlm->reco.new_master);
			destroy = 1;
			status = ret;
			/* rescan everything marked dirty along the way */
			dlm_kick_thread(dlm, NULL);
			break;
		}
		/* wait to be signalled, with periodic timeout
		 * to check for node death */
		wait_event_interruptible_timeout(dlm->dlm_reco_thread_wq,
					 kthread_should_stop(),
					 msecs_to_jiffies(DLM_RECO_THREAD_TIMEOUT_MS));

	}

leave:
	if (destroy)
		dlm_destroy_recovery_area(dlm, dead_node);

	mlog_exit(status);
	return status;
}

static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
	int num=0;
	struct dlm_reco_node_data *ndata;

	spin_lock(&dlm->spinlock);
	memcpy(dlm->reco.node_map, dlm->domain_map, sizeof(dlm->domain_map));
	/* nodes can only be removed (by dying) after dropping
	 * this lock, and death will be trapped later, so this should do */
	spin_unlock(&dlm->spinlock);

	while (1) {
		num = find_next_bit (dlm->reco.node_map, O2NM_MAX_NODES, num);
		if (num >= O2NM_MAX_NODES) {
			break;
		}
		BUG_ON(num == dead_node);

		ndata = kcalloc(1, sizeof(*ndata), GFP_KERNEL);
		if (!ndata) {
			dlm_destroy_recovery_area(dlm, dead_node);
			return -ENOMEM;
		}
		ndata->node_num = num;
		ndata->state = DLM_RECO_NODE_DATA_INIT;
		spin_lock(&dlm_reco_state_lock);
		list_add_tail(&ndata->list, &dlm->reco.node_data);
		spin_unlock(&dlm_reco_state_lock);
		num++;
	}

	return 0;
}

static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
	struct list_head *iter, *iter2;
	struct dlm_reco_node_data *ndata;
	LIST_HEAD(tmplist);

	spin_lock(&dlm_reco_state_lock);
	list_splice_init(&dlm->reco.node_data, &tmplist);
	spin_unlock(&dlm_reco_state_lock);

	list_for_each_safe(iter, iter2, &tmplist) {
		ndata = list_entry (iter, struct dlm_reco_node_data, list);
		list_del_init(&ndata->list);
		kfree(ndata);
	}
}

static int dlm_request_all_locks(struct dlm_ctxt *dlm, u8 request_from,
				 u8 dead_node)
{
	struct dlm_lock_request lr;
	enum dlm_status ret;

	mlog(0, "\n");


	mlog(0, "dlm_request_all_locks: dead node is %u, sending request "
		  "to %u\n", dead_node, request_from);

	memset(&lr, 0, sizeof(lr));
	lr.node_idx = dlm->node_num;
	lr.dead_node = dead_node;

	// send message
	ret = DLM_NOLOCKMGR;
	ret = o2net_send_message(DLM_LOCK_REQUEST_MSG, dlm->key,
				 &lr, sizeof(lr), request_from, NULL);

	/* negative status is handled by caller */
	if (ret < 0)
		mlog_errno(ret);

	// return from here, then
	// sleep until all received or error
	return ret;

}

int dlm_request_all_locks_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_lock_request *lr = (struct dlm_lock_request *)msg->buf;
	char *buf = NULL;
	struct dlm_work_item *item = NULL;

	if (!dlm_grab(dlm))
		return -EINVAL;

	BUG_ON(lr->dead_node != dlm->reco.dead_node);

	item = kcalloc(1, sizeof(*item), GFP_KERNEL);
	if (!item) {
		dlm_put(dlm);
		return -ENOMEM;
	}

	/* this will get freed by dlm_request_all_locks_worker */
	buf = (char *) __get_free_page(GFP_KERNEL);
	if (!buf) {
		kfree(item);
		dlm_put(dlm);
		return -ENOMEM;
	}

	/* queue up work for dlm_request_all_locks_worker */
	dlm_grab(dlm);  /* get an extra ref for the work item */
	dlm_init_work_item(dlm, item, dlm_request_all_locks_worker, buf);
	item->u.ral.reco_master = lr->node_idx;
	item->u.ral.dead_node = lr->dead_node;
	spin_lock(&dlm->work_lock);
	list_add_tail(&item->list, &dlm->work_list);
	spin_unlock(&dlm->work_lock);
	schedule_work(&dlm->dispatched_work);

	dlm_put(dlm);
	return 0;
}

static void dlm_request_all_locks_worker(struct dlm_work_item *item, void *data)
{
	struct dlm_migratable_lockres *mres;
	struct dlm_lock_resource *res;
	struct dlm_ctxt *dlm;
	LIST_HEAD(resources);
	struct list_head *iter;
	int ret;
	u8 dead_node, reco_master;

	dlm = item->dlm;
	dead_node = item->u.ral.dead_node;
	reco_master = item->u.ral.reco_master;
	mres = (struct dlm_migratable_lockres *)data;

	if (dead_node != dlm->reco.dead_node ||
	    reco_master != dlm->reco.new_master) {
		/* show extra debug info if the recovery state is messed */
		mlog(ML_ERROR, "%s: bad reco state: reco(dead=%u, master=%u), "
		     "request(dead=%u, master=%u)\n",
		     dlm->name, dlm->reco.dead_node, dlm->reco.new_master,
		     dead_node, reco_master);
		mlog(ML_ERROR, "%s: name=%.*s master=%u locks=%u/%u flags=%u "
		     "entry[0]={c=%"MLFu64",l=%u,f=%u,t=%d,ct=%d,hb=%d,n=%u}\n",
		     dlm->name, mres->lockname_len, mres->lockname, mres->master,
		     mres->num_locks, mres->total_locks, mres->flags,
		     mres->ml[0].cookie, mres->ml[0].list, mres->ml[0].flags,
		     mres->ml[0].type, mres->ml[0].convert_type,
		     mres->ml[0].highest_blocked, mres->ml[0].node);
		BUG();
	}
	BUG_ON(dead_node != dlm->reco.dead_node);
	BUG_ON(reco_master != dlm->reco.new_master);

	/* lock resources should have already been moved to the
 	 * dlm->reco.resources list.  now move items from that list
 	 * to a temp list if the dead owner matches.  note that the
	 * whole cluster recovers only one node at a time, so we
	 * can safely move UNKNOWN lock resources for each recovery
	 * session. */
	dlm_move_reco_locks_to_list(dlm, &resources, dead_node);

	/* now we can begin blasting lockreses without the dlm lock */
	list_for_each(iter, &resources) {
		res = list_entry (iter, struct dlm_lock_resource, recovering);
		ret = dlm_send_one_lockres(dlm, res, mres, reco_master,
				   	DLM_MRES_RECOVERY);
		if (ret < 0)
			mlog_errno(ret);
	}

	/* move the resources back to the list */
	spin_lock(&dlm->spinlock);
	list_splice_init(&resources, &dlm->reco.resources);
	spin_unlock(&dlm->spinlock);

	ret = dlm_send_all_done_msg(dlm, dead_node, reco_master);
	if (ret < 0)
		mlog_errno(ret);

	free_page((unsigned long)data);
}


static int dlm_send_all_done_msg(struct dlm_ctxt *dlm, u8 dead_node, u8 send_to)
{
	int ret, tmpret;
	struct dlm_reco_data_done done_msg;

	memset(&done_msg, 0, sizeof(done_msg));
	done_msg.node_idx = dlm->node_num;
	done_msg.dead_node = dead_node;
	mlog(0, "sending DATA DONE message to %u, "
	     "my node=%u, dead node=%u\n", send_to, done_msg.node_idx,
	     done_msg.dead_node);

	ret = o2net_send_message(DLM_RECO_DATA_DONE_MSG, dlm->key, &done_msg,
				 sizeof(done_msg), send_to, &tmpret);
	/* negative status is ignored by the caller */
	if (ret >= 0)
		ret = tmpret;
	return ret;
}


int dlm_reco_data_done_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_reco_data_done *done = (struct dlm_reco_data_done *)msg->buf;
	struct list_head *iter;
	struct dlm_reco_node_data *ndata = NULL;
	int ret = -EINVAL;

	if (!dlm_grab(dlm))
		return -EINVAL;

	mlog(0, "got DATA DONE: dead_node=%u, reco.dead_node=%u, "
	     "node_idx=%u, this node=%u\n", done->dead_node,
	     dlm->reco.dead_node, done->node_idx, dlm->node_num);
	BUG_ON(done->dead_node != dlm->reco.dead_node);

	spin_lock(&dlm_reco_state_lock);
	list_for_each(iter, &dlm->reco.node_data) {
		ndata = list_entry (iter, struct dlm_reco_node_data, list);
		if (ndata->node_num != done->node_idx)
			continue;

		switch (ndata->state) {
			/* should have moved beyond INIT but not to FINALIZE yet */
			case DLM_RECO_NODE_DATA_INIT:
			case DLM_RECO_NODE_DATA_DEAD:
			case DLM_RECO_NODE_DATA_FINALIZE_SENT:
				mlog(ML_ERROR, "bad ndata state for node %u:"
				     " state=%d\n", ndata->node_num,
				     ndata->state);
				BUG();
				break;
			/* these states are possible at this point, anywhere along
			 * the line of recovery */
			case DLM_RECO_NODE_DATA_DONE:
			case DLM_RECO_NODE_DATA_RECEIVING:
			case DLM_RECO_NODE_DATA_REQUESTED:
			case DLM_RECO_NODE_DATA_REQUESTING:
				mlog(0, "node %u is DONE sending "
					  "recovery data!\n",
					  ndata->node_num);

				ndata->state = DLM_RECO_NODE_DATA_DONE;
				ret = 0;
				break;
		}
	}
	spin_unlock(&dlm_reco_state_lock);

	/* wake the recovery thread, some node is done */
	if (!ret)
		dlm_kick_recovery_thread(dlm);

	if (ret < 0)
		mlog(ML_ERROR, "failed to find recovery node data for node "
		     "%u\n", done->node_idx);
	dlm_put(dlm);

	mlog(0, "leaving reco data done handler, ret=%d\n", ret);
	return ret;
}

static void dlm_move_reco_locks_to_list(struct dlm_ctxt *dlm,
					struct list_head *list,
				       	u8 dead_node)
{
	struct dlm_lock_resource *res;
	struct list_head *iter, *iter2;
	struct dlm_lock *lock;

	spin_lock(&dlm->spinlock);
	list_for_each_safe(iter, iter2, &dlm->reco.resources) {
		res = list_entry (iter, struct dlm_lock_resource, recovering);
		/* always prune any $RECOVERY entries for dead nodes,
		 * otherwise hangs can occur during later recovery */
		if (dlm_is_recovery_lock(res->lockname.name,
					 res->lockname.len)) {
			spin_lock(&res->spinlock);
			list_for_each_entry(lock, &res->granted, list) {
				if (lock->ml.node == dead_node) {
					mlog(0, "AHA! there was "
					     "a $RECOVERY lock for dead "
					     "node %u (%s)!\n", 
					     dead_node, dlm->name);
					list_del_init(&lock->list);
					dlm_lock_put(lock);
					break;
				}
			}
			spin_unlock(&res->spinlock);
			continue;
		}

		if (res->owner == dead_node) {
			mlog(0, "found lockres owned by dead node while "
				  "doing recovery for node %u. sending it.\n",
				  dead_node);
			list_del_init(&res->recovering);
			list_add_tail(&res->recovering, list);
		} else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
			mlog(0, "found UNKNOWN owner while doing recovery "
				  "for node %u. sending it.\n", dead_node);
			list_del_init(&res->recovering);
			list_add_tail(&res->recovering, list);
		}
	}
	spin_unlock(&dlm->spinlock);
}

static inline int dlm_num_locks_in_lockres(struct dlm_lock_resource *res)
{
	int total_locks = 0;
	struct list_head *iter, *queue = &res->granted;
	int i;

	for (i=0; i<3; i++) {
		list_for_each(iter, queue)
			total_locks++;
		queue++;
	}
	return total_locks;
}


static int dlm_send_mig_lockres_msg(struct dlm_ctxt *dlm,
				      struct dlm_migratable_lockres *mres,
				      u8 send_to,
				      struct dlm_lock_resource *res,
				      int total_locks)
{
	u64 mig_cookie = be64_to_cpu(mres->mig_cookie);
	int mres_total_locks = be32_to_cpu(mres->total_locks);
	int sz, ret = 0, status = 0;
	u8 orig_flags = mres->flags,
	   orig_master = mres->master;

	BUG_ON(mres->num_locks > DLM_MAX_MIGRATABLE_LOCKS);
	if (!mres->num_locks)
		return 0;

	sz = sizeof(struct dlm_migratable_lockres) +
		(mres->num_locks * sizeof(struct dlm_migratable_lock));

	/* add an all-done flag if we reached the last lock */
	orig_flags = mres->flags;
	BUG_ON(total_locks > mres_total_locks);
	if (total_locks == mres_total_locks)
		mres->flags |= DLM_MRES_ALL_DONE;

	/* send it */
	ret = o2net_send_message(DLM_MIG_LOCKRES_MSG, dlm->key, mres,
				 sz, send_to, &status);
	if (ret < 0) {
		/* XXX: negative status is not handled.
		 * this will end up killing this node. */
		mlog_errno(ret);
	} else {
		/* might get an -ENOMEM back here */
		ret = status;
		if (ret < 0) {
			mlog_errno(ret);

			if (ret == -EFAULT) {
				mlog(ML_ERROR, "node %u told me to kill "
				     "myself!\n", send_to);
				BUG();
			}
		}
	}

	/* zero and reinit the message buffer */
	dlm_init_migratable_lockres(mres, res->lockname.name,
				    res->lockname.len, mres_total_locks,
				    mig_cookie, orig_flags, orig_master);
	return ret;
}

static void dlm_init_migratable_lockres(struct dlm_migratable_lockres *mres,
					const char *lockname, int namelen,
					int total_locks, u64 cookie,
					u8 flags, u8 master)
{
	/* mres here is one full page */
	memset(mres, 0, PAGE_SIZE);
	mres->lockname_len = namelen;
	memcpy(mres->lockname, lockname, namelen);
	mres->num_locks = 0;
	mres->total_locks = cpu_to_be32(total_locks);
	mres->mig_cookie = cpu_to_be64(cookie);
	mres->flags = flags;
	mres->master = master;
}


/* returns 1 if this lock fills the network structure,
 * 0 otherwise */
static int dlm_add_lock_to_array(struct dlm_lock *lock,
				 struct dlm_migratable_lockres *mres, int queue)
{
	struct dlm_migratable_lock *ml;
	int lock_num = mres->num_locks;

	ml = &(mres->ml[lock_num]);
	ml->cookie = lock->ml.cookie;
	ml->type = lock->ml.type;
	ml->convert_type = lock->ml.convert_type;
	ml->highest_blocked = lock->ml.highest_blocked;
	ml->list = queue;
	if (lock->lksb) {
		ml->flags = lock->lksb->flags;
		/* send our current lvb */
		if (ml->type == LKM_EXMODE ||
		    ml->type == LKM_PRMODE) {
			/* if it is already set, this had better be a PR
			 * and it has to match */
			if (mres->lvb[0] && (ml->type == LKM_EXMODE ||
			    memcmp(mres->lvb, lock->lksb->lvb, DLM_LVB_LEN))) {
				mlog(ML_ERROR, "mismatched lvbs!\n");
				__dlm_print_one_lock_resource(lock->lockres);
				BUG();
			}
			memcpy(mres->lvb, lock->lksb->lvb, DLM_LVB_LEN);
		}
	}
	ml->node = lock->ml.node;
	mres->num_locks++;
	/* we reached the max, send this network message */
	if (mres->num_locks == DLM_MAX_MIGRATABLE_LOCKS)
		return 1;
	return 0;
}


int dlm_send_one_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
			 struct dlm_migratable_lockres *mres,
			 u8 send_to, u8 flags)
{
	struct list_head *queue, *iter;
	int total_locks, i;
	u64 mig_cookie = 0;
	struct dlm_lock *lock;
	int ret = 0;

	BUG_ON(!(flags & (DLM_MRES_RECOVERY|DLM_MRES_MIGRATION)));

	mlog(0, "sending to %u\n", send_to);

	total_locks = dlm_num_locks_in_lockres(res);
	if (total_locks > DLM_MAX_MIGRATABLE_LOCKS) {
		/* rare, but possible */
		mlog(0, "argh.  lockres has %d locks.  this will "
			  "require more than one network packet to "
			  "migrate\n", total_locks);
		mig_cookie = dlm_get_next_mig_cookie();
	}

	dlm_init_migratable_lockres(mres, res->lockname.name,
				    res->lockname.len, total_locks,
				    mig_cookie, flags, res->owner);

	total_locks = 0;
	for (i=DLM_GRANTED_LIST; i<=DLM_BLOCKED_LIST; i++) {
		queue = dlm_list_idx_to_ptr(res, i);
		list_for_each(iter, queue) {
			lock = list_entry (iter, struct dlm_lock, list);

			/* add another lock. */
			total_locks++;
			if (!dlm_add_lock_to_array(lock, mres, i))
				continue;

			/* this filled the lock message,
			 * we must send it immediately. */
			ret = dlm_send_mig_lockres_msg(dlm, mres, send_to,
						       res, total_locks);
			if (ret < 0) {
				// TODO
				mlog(ML_ERROR, "dlm_send_mig_lockres_msg "
				     "returned %d, TODO\n", ret);
				BUG();
			}
		}
	}
	/* flush any remaining locks */
	ret = dlm_send_mig_lockres_msg(dlm, mres, send_to, res, total_locks);
	if (ret < 0) {
		// TODO
		mlog(ML_ERROR, "dlm_send_mig_lockres_msg returned %d, "
		     "TODO\n", ret);
		BUG();
	}
	return ret;
}



/*
 * this message will contain no more than one page worth of
 * recovery data, and it will work on only one lockres.
 * there may be many locks in this page, and we may need to wait
 * for additional packets to complete all the locks (rare, but
 * possible).
 */
/*
 * NOTE: the allocation error cases here are scary
 * we really cannot afford to fail an alloc in recovery
 * do we spin?  returning an error only delays the problem really
 */

int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_migratable_lockres *mres =
		(struct dlm_migratable_lockres *)msg->buf;
	int ret = 0;
	u8 real_master;
	char *buf = NULL;
	struct dlm_work_item *item = NULL;
	struct dlm_lock_resource *res = NULL;

	if (!dlm_grab(dlm))
		return -EINVAL;

	BUG_ON(!(mres->flags & (DLM_MRES_RECOVERY|DLM_MRES_MIGRATION)));

	real_master = mres->master;
	if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
		/* cannot migrate a lockres with no master */
		BUG_ON(!(mres->flags & DLM_MRES_RECOVERY));
	}

	mlog(0, "%s message received from node %u\n",
		  (mres->flags & DLM_MRES_RECOVERY) ?
		  "recovery" : "migration", mres->master);
	if (mres->flags & DLM_MRES_ALL_DONE)
		mlog(0, "all done flag.  all lockres data received!\n");

	ret = -ENOMEM;
	buf = kmalloc(be16_to_cpu(msg->data_len), GFP_KERNEL);
	item = kcalloc(1, sizeof(*item), GFP_KERNEL);
	if (!buf || !item)
		goto leave;

	/* lookup the lock to see if we have a secondary queue for this
	 * already...  just add the locks in and this will have its owner
	 * and RECOVERY flag changed when it completes. */
	res = dlm_lookup_lockres(dlm, mres->lockname, mres->lockname_len);
	if (res) {
	 	/* this will get a ref on res */
		/* mark it as recovering/migrating and hash it */
		spin_lock(&res->spinlock);
		if (mres->flags & DLM_MRES_RECOVERY) {
			res->state |= DLM_LOCK_RES_RECOVERING;
		} else {
			if (res->state & DLM_LOCK_RES_MIGRATING) {
				/* this is at least the second
				 * lockres message */
				mlog(0, "lock %.*s is already migrating\n",
					  mres->lockname_len,
					  mres->lockname);
			} else if (res->state & DLM_LOCK_RES_RECOVERING) {
				/* caller should BUG */
				mlog(ML_ERROR, "node is attempting to migrate "
				     "lock %.*s, but marked as recovering!\n",
				     mres->lockname_len, mres->lockname);
				ret = -EFAULT;
				spin_unlock(&res->spinlock);
				goto leave;
			}
			res->state |= DLM_LOCK_RES_MIGRATING;
		}
		spin_unlock(&res->spinlock);
	} else {
		/* need to allocate, just like if it was
		 * mastered here normally  */
		res = dlm_new_lockres(dlm, mres->lockname, mres->lockname_len);
		if (!res)
			goto leave;

		/* to match the ref that we would have gotten if
		 * dlm_lookup_lockres had succeeded */
		dlm_lockres_get(res);

		/* mark it as recovering/migrating and hash it */
		if (mres->flags & DLM_MRES_RECOVERY)
			res->state |= DLM_LOCK_RES_RECOVERING;
		else
			res->state |= DLM_LOCK_RES_MIGRATING;

		spin_lock(&dlm->spinlock);
		__dlm_insert_lockres(dlm, res);
		spin_unlock(&dlm->spinlock);

		/* now that the new lockres is inserted,
		 * make it usable by other processes */
		spin_lock(&res->spinlock);
		res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
		spin_unlock(&res->spinlock);

		/* add an extra ref for just-allocated lockres 
		 * otherwise the lockres will be purged immediately */
		dlm_lockres_get(res);

	}

	/* at this point we have allocated everything we need,
	 * and we have a hashed lockres with an extra ref and
	 * the proper res->state flags. */
	ret = 0;
	if (mres->master == DLM_LOCK_RES_OWNER_UNKNOWN) {
		/* migration cannot have an unknown master */
		BUG_ON(!(mres->flags & DLM_MRES_RECOVERY));
		mlog(0, "recovery has passed me a lockres with an "
			  "unknown owner.. will need to requery: "
			  "%.*s\n", mres->lockname_len, mres->lockname);
	} else {
		spin_lock(&res->spinlock);
		dlm_change_lockres_owner(dlm, res, dlm->node_num);
		spin_unlock(&res->spinlock);
	}

	/* queue up work for dlm_mig_lockres_worker */
	dlm_grab(dlm);  /* get an extra ref for the work item */
	memcpy(buf, msg->buf, be16_to_cpu(msg->data_len));  /* copy the whole message */
	dlm_init_work_item(dlm, item, dlm_mig_lockres_worker, buf);
	item->u.ml.lockres = res; /* already have a ref */
	item->u.ml.real_master = real_master;
	spin_lock(&dlm->work_lock);
	list_add_tail(&item->list, &dlm->work_list);
	spin_unlock(&dlm->work_lock);
	schedule_work(&dlm->dispatched_work);

leave:
	dlm_put(dlm);
	if (ret < 0) {
		if (buf)
			kfree(buf);
		if (item)
			kfree(item);
	}

	mlog_exit(ret);
	return ret;
}


static void dlm_mig_lockres_worker(struct dlm_work_item *item, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_migratable_lockres *mres;
	int ret = 0;
	struct dlm_lock_resource *res;
	u8 real_master;

	dlm = item->dlm;
	mres = (struct dlm_migratable_lockres *)data;

	res = item->u.ml.lockres;
	real_master = item->u.ml.real_master;

	if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
		/* this case is super-rare. only occurs if
		 * node death happens during migration. */
again:
		ret = dlm_lockres_master_requery(dlm, res, &real_master);
		if (ret < 0) {
			mlog(0, "dlm_lockres_master_requery ret=%d\n",
				  ret);
			goto again;
		}
		if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
			mlog(0, "lockres %.*s not claimed.  "
				   "this node will take it.\n",
				   res->lockname.len, res->lockname.name);
		} else {
			mlog(0, "master needs to respond to sender "
				  "that node %u still owns %.*s\n",
				  real_master, res->lockname.len,
				  res->lockname.name);
			/* cannot touch this lockres */
			goto leave;
		}
	}

	ret = dlm_process_recovery_data(dlm, res, mres);
	if (ret < 0)
		mlog(0, "dlm_process_recovery_data returned  %d\n", ret);
	else
		mlog(0, "dlm_process_recovery_data succeeded\n");

	if ((mres->flags & (DLM_MRES_MIGRATION|DLM_MRES_ALL_DONE)) ==
	                   (DLM_MRES_MIGRATION|DLM_MRES_ALL_DONE)) {
		ret = dlm_finish_migration(dlm, res, mres->master);
		if (ret < 0)
			mlog_errno(ret);
	}

leave:
	kfree(data);
	mlog_exit(ret);
}



static int dlm_lockres_master_requery(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res,
				      u8 *real_master)
{
	struct dlm_node_iter iter;
	int nodenum;
	int ret = 0;

	*real_master = DLM_LOCK_RES_OWNER_UNKNOWN;

	/* we only reach here if one of the two nodes in a
	 * migration died while the migration was in progress.
	 * at this point we need to requery the master.  we
	 * know that the new_master got as far as creating
	 * an mle on at least one node, but we do not know
	 * if any nodes had actually cleared the mle and set
	 * the master to the new_master.  the old master
	 * is supposed to set the owner to UNKNOWN in the
	 * event of a new_master death, so the only possible
	 * responses that we can get from nodes here are
	 * that the master is new_master, or that the master
	 * is UNKNOWN.
	 * if all nodes come back with UNKNOWN then we know
	 * the lock needs remastering here.
	 * if any node comes back with a valid master, check
	 * to see if that master is the one that we are
	 * recovering.  if so, then the new_master died and
	 * we need to remaster this lock.  if not, then the
	 * new_master survived and that node will respond to
	 * other nodes about the owner.
	 * if there is an owner, this node needs to dump this
	 * lockres and alert the sender that this lockres
	 * was rejected. */
	spin_lock(&dlm->spinlock);
	dlm_node_iter_init(dlm->domain_map, &iter);
	spin_unlock(&dlm->spinlock);

	while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
		/* do not send to self */
		if (nodenum == dlm->node_num)
			continue;
		ret = dlm_do_master_requery(dlm, res, nodenum, real_master);
		if (ret < 0) {
			mlog_errno(ret);
			BUG();
			/* TODO: need to figure a way to restart this */
		}
		if (*real_master != DLM_LOCK_RES_OWNER_UNKNOWN) {
			mlog(0, "lock master is %u\n", *real_master);
			break;
		}
	}
	return ret;
}


static int dlm_do_master_requery(struct dlm_ctxt *dlm,
				 struct dlm_lock_resource *res,
				 u8 nodenum, u8 *real_master)
{
	int ret = -EINVAL;
	struct dlm_master_requery req;
	int status = DLM_LOCK_RES_OWNER_UNKNOWN;

	memset(&req, 0, sizeof(req));
	req.node_idx = dlm->node_num;
	req.namelen = res->lockname.len;
	memcpy(req.name, res->lockname.name, res->lockname.len);

	ret = o2net_send_message(DLM_MASTER_REQUERY_MSG, dlm->key,
				 &req, sizeof(req), nodenum, &status);
	/* XXX: negative status not handled properly here. */
	if (ret < 0)
		mlog_errno(ret);
	else {
		BUG_ON(status < 0);
		BUG_ON(status > DLM_LOCK_RES_OWNER_UNKNOWN);
		*real_master = (u8) (status & 0xff);
		mlog(0, "node %u responded to master requery with %u\n",
			  nodenum, *real_master);
		ret = 0;
	}
	return ret;
}


/* this function cannot error, so unless the sending
 * or receiving of the message failed, the owner can
 * be trusted */
int dlm_master_requery_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_master_requery *req = (struct dlm_master_requery *)msg->buf;
	struct dlm_lock_resource *res = NULL;
	int master = DLM_LOCK_RES_OWNER_UNKNOWN;
	u32 flags = DLM_ASSERT_MASTER_REQUERY;

	if (!dlm_grab(dlm)) {
		/* since the domain has gone away on this
		 * node, the proper response is UNKNOWN */
		return master;
	}

	spin_lock(&dlm->spinlock);
	res = __dlm_lookup_lockres(dlm, req->name, req->namelen);
	if (res) {
		spin_lock(&res->spinlock);
		master = res->owner;
		if (master == dlm->node_num) {
			int ret = dlm_dispatch_assert_master(dlm, res,
							     0, 0, flags);
			if (ret < 0) {
				mlog_errno(-ENOMEM);
				/* retry!? */
				BUG();
			}
		}
		spin_unlock(&res->spinlock);
	}
	spin_unlock(&dlm->spinlock);

	dlm_put(dlm);
	return master;
}

static inline struct list_head *
dlm_list_num_to_pointer(struct dlm_lock_resource *res, int list_num)
{
	struct list_head *ret;
	BUG_ON(list_num < 0);
	BUG_ON(list_num > 2);
	ret = &(res->granted);
	ret += list_num;
	return ret;
}
/* TODO: do ast flush business
 * TODO: do MIGRATING and RECOVERING spinning
 */

/*
* NOTE about in-flight requests during migration:
*
* Before attempting the migrate, the master has marked the lockres as
* MIGRATING and then flushed all of its pending ASTS.  So any in-flight
* requests either got queued before the MIGRATING flag got set, in which
* case the lock data will reflect the change and a return message is on
* the way, or the request failed to get in before MIGRATING got set.  In
* this case, the caller will be told to spin and wait for the MIGRATING
* flag to be dropped, then recheck the master.
* This holds true for the convert, cancel and unlock cases, and since lvb
* updates are tied to these same messages, it applies to lvb updates as
* well.  For the lock case, there is no way a lock can be on the master
* queue and not be on the secondary queue since the lock is always added
* locally first.  This means that the new target node will never be sent
* a lock that he doesn't already have on the list.
* In total, this means that the local lock is correct and should not be
* updated to match the one sent by the master.  Any messages sent back
* from the master before the MIGRATING flag will bring the lock properly
* up-to-date, and the change will be ordered properly for the waiter.
* We will *not* attempt to modify the lock underneath the waiter.
*/

static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
				     struct dlm_lock_resource *res,
				     struct dlm_migratable_lockres *mres)
{
	struct dlm_migratable_lock *ml;
	struct list_head *queue;
	struct dlm_lock *newlock = NULL;
	struct dlm_lockstatus *lksb = NULL;
	int ret = 0;
	int i;
	struct list_head *iter;
	struct dlm_lock *lock = NULL;

	mlog(0, "running %d locks for this lockres\n", mres->num_locks);
	for (i=0; i<mres->num_locks; i++) {
		ml = &(mres->ml[i]);
		BUG_ON(ml->highest_blocked != LKM_IVMODE);
		newlock = NULL;
		lksb = NULL;

		queue = dlm_list_num_to_pointer(res, ml->list);

		/* if the lock is for the local node it needs to
		 * be moved to the proper location within the queue.
		 * do not allocate a new lock structure. */
		if (ml->node == dlm->node_num) {
			/* MIGRATION ONLY! */
			BUG_ON(!(mres->flags & DLM_MRES_MIGRATION));

			spin_lock(&res->spinlock);
			list_for_each(iter, queue) {
				lock = list_entry (iter, struct dlm_lock, list);
				if (lock->ml.cookie != ml->cookie)
					lock = NULL;
				else
					break;
			}

			/* lock is always created locally first, and
			 * destroyed locally last.  it must be on the list */
			if (!lock) {
				mlog(ML_ERROR, "could not find local lock "
					       "with cookie %"MLFu64"!\n",
				     ml->cookie);
				BUG();
			}
			BUG_ON(lock->ml.node != ml->node);

			/* see NOTE above about why we do not update
			 * to match the master here */

			/* move the lock to its proper place */
			/* do not alter lock refcount.  switching lists. */
			list_del_init(&lock->list);
			list_add_tail(&lock->list, queue);
			spin_unlock(&res->spinlock);

			mlog(0, "just reordered a local lock!\n");
			continue;
		}

		/* lock is for another node. */
		newlock = dlm_new_lock(ml->type, ml->node,
				       be64_to_cpu(ml->cookie), NULL);
		if (!newlock) {
			ret = -ENOMEM;
			goto leave;
		}
		lksb = newlock->lksb;
		dlm_lock_attach_lockres(newlock, res);

		if (ml->convert_type != LKM_IVMODE) {
			BUG_ON(queue != &res->converting);
			newlock->ml.convert_type = ml->convert_type;
		}
		lksb->flags |= (ml->flags &
				(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
			
		if (mres->lvb[0]) {
			if (lksb->flags & DLM_LKSB_PUT_LVB) {
				/* other node was trying to update
				 * lvb when node died.  recreate the
				 * lksb with the updated lvb. */
				memcpy(lksb->lvb, mres->lvb, DLM_LVB_LEN);
			} else {
				/* otherwise, the node is sending its 
				 * most recent valid lvb info */
				BUG_ON(ml->type != LKM_EXMODE &&
				       ml->type != LKM_PRMODE);
				if (res->lvb[0] && (ml->type == LKM_EXMODE ||
				    memcmp(res->lvb, mres->lvb, DLM_LVB_LEN))) {
					mlog(ML_ERROR, "received bad lvb!\n");
					__dlm_print_one_lock_resource(res);
					BUG();
				}
				memcpy(res->lvb, mres->lvb, DLM_LVB_LEN);
			}
		}


		/* NOTE:
		 * wrt lock queue ordering and recovery:
		 *    1. order of locks on granted queue is
		 *       meaningless.
		 *    2. order of locks on converting queue is
		 *       LOST with the node death.  sorry charlie.
		 *    3. order of locks on the blocked queue is
		 *       also LOST.
		 * order of locks does not affect integrity, it
		 * just means that a lock request may get pushed
		 * back in line as a result of the node death.
		 * also note that for a given node the lock order
		 * for its secondary queue locks is preserved
		 * relative to each other, but clearly *not*
		 * preserved relative to locks from other nodes.
		 */
		spin_lock(&res->spinlock);
		dlm_lock_get(newlock);
		list_add_tail(&newlock->list, queue);
		spin_unlock(&res->spinlock);
	}
	mlog(0, "done running all the locks\n");

leave:
	if (ret < 0) {
		mlog_errno(ret);
		if (newlock)
			dlm_lock_put(newlock);
	}

	mlog_exit(ret);
	return ret;
}

void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
				       struct dlm_lock_resource *res)
{
	int i;
	struct list_head *queue, *iter, *iter2;
	struct dlm_lock *lock;

	res->state |= DLM_LOCK_RES_RECOVERING;
	if (!list_empty(&res->recovering))
		list_del_init(&res->recovering);
	list_add_tail(&res->recovering, &dlm->reco.resources);

	/* find any pending locks and put them back on proper list */
	for (i=DLM_BLOCKED_LIST; i>=DLM_GRANTED_LIST; i--) {
		queue = dlm_list_idx_to_ptr(res, i);
		list_for_each_safe(iter, iter2, queue) {
			lock = list_entry (iter, struct dlm_lock, list);
			dlm_lock_get(lock);
			if (lock->convert_pending) {
				/* move converting lock back to granted */
				BUG_ON(i != DLM_CONVERTING_LIST);
				mlog(0, "node died with convert pending "
				     "on %.*s. move back to granted list.\n",
				     res->lockname.len, res->lockname.name);
				dlm_revert_pending_convert(res, lock);
				lock->convert_pending = 0;
			} else if (lock->lock_pending) {
				/* remove pending lock requests completely */
				BUG_ON(i != DLM_BLOCKED_LIST);
				mlog(0, "node died with lock pending "
				     "on %.*s. remove from blocked list and skip.\n",
				     res->lockname.len, res->lockname.name);
				/* lock will be floating until ref in
				 * dlmlock_remote is freed after the network
				 * call returns.  ok for it to not be on any
				 * list since no ast can be called
				 * (the master is dead). */
				dlm_revert_pending_lock(res, lock);
				lock->lock_pending = 0;
			} else if (lock->unlock_pending) {
				/* if an unlock was in progress, treat as
				 * if this had completed successfully
				 * before sending this lock state to the
				 * new master.  note that the dlm_unlock
				 * call is still responsible for calling
				 * the unlockast.  that will happen after
				 * the network call times out.  for now,
				 * just move lists to prepare the new
				 * recovery master.  */
				BUG_ON(i != DLM_GRANTED_LIST);
				mlog(0, "node died with unlock pending "
				     "on %.*s. remove from blocked list and skip.\n",
				     res->lockname.len, res->lockname.name);
				dlm_commit_pending_unlock(res, lock);
				lock->unlock_pending = 0;
			} else if (lock->cancel_pending) {
				/* if a cancel was in progress, treat as
				 * if this had completed successfully
				 * before sending this lock state to the
				 * new master */
				BUG_ON(i != DLM_CONVERTING_LIST);
				mlog(0, "node died with cancel pending "
				     "on %.*s. move back to granted list.\n",
				     res->lockname.len, res->lockname.name);
				dlm_commit_pending_cancel(res, lock);
				lock->cancel_pending = 0;
			}
			dlm_lock_put(lock);
		}
	}
}



/* removes all recovered locks from the recovery list.
 * sets the res->owner to the new master.
 * unsets the RECOVERY flag and wakes waiters. */
static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
					      u8 dead_node, u8 new_master)
{
	int i;
	struct list_head *iter, *iter2, *bucket;
	struct dlm_lock_resource *res;

	mlog_entry_void();

	assert_spin_locked(&dlm->spinlock);

	list_for_each_safe(iter, iter2, &dlm->reco.resources) {
		res = list_entry (iter, struct dlm_lock_resource, recovering);
		if (res->owner == dead_node) {
			list_del_init(&res->recovering);
			spin_lock(&res->spinlock);
			dlm_change_lockres_owner(dlm, res, new_master);
			res->state &= ~DLM_LOCK_RES_RECOVERING;
			__dlm_dirty_lockres(dlm, res);
			spin_unlock(&res->spinlock);
			wake_up(&res->wq);
		}
	}

	/* this will become unnecessary eventually, but
	 * for now we need to run the whole hash, clear
	 * the RECOVERING state and set the owner
	 * if necessary */
	for (i=0; i<DLM_HASH_SIZE; i++) {
		bucket = &(dlm->resources[i]);
		list_for_each(iter, bucket) {
			res = list_entry (iter, struct dlm_lock_resource, list);
			if (res->state & DLM_LOCK_RES_RECOVERING) {
				if (res->owner == dead_node) {
					mlog(0, "(this=%u) res %.*s owner=%u "
					     "was not on recovering list, but "
					     "clearing state anyway\n",
					     dlm->node_num, res->lockname.len,
					     res->lockname.name, new_master);
				} else if (res->owner == dlm->node_num) {
					mlog(0, "(this=%u) res %.*s owner=%u "
					     "was not on recovering list, "
					     "owner is THIS node, clearing\n",
					     dlm->node_num, res->lockname.len,
					     res->lockname.name, new_master);
				} else
					continue;

				spin_lock(&res->spinlock);
				dlm_change_lockres_owner(dlm, res, new_master);
				res->state &= ~DLM_LOCK_RES_RECOVERING;
				__dlm_dirty_lockres(dlm, res);
				spin_unlock(&res->spinlock);
				wake_up(&res->wq);
			}
		}
	}
}

static inline int dlm_lvb_needs_invalidation(struct dlm_lock *lock, int local)
{
	if (local) {
		if (lock->ml.type != LKM_EXMODE &&
		    lock->ml.type != LKM_PRMODE)
			return 1;
	} else if (lock->ml.type == LKM_EXMODE)
		return 1;
	return 0;
}

static void dlm_revalidate_lvb(struct dlm_ctxt *dlm,
			       struct dlm_lock_resource *res, u8 dead_node)
{
	struct list_head *iter, *queue;
	struct dlm_lock *lock;
	int blank_lvb = 0, local = 0;
	int i;
	u8 search_node;

	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&res->spinlock);

	if (res->owner == dlm->node_num)
		/* if this node owned the lockres, and if the dead node 
		 * had an EX when he died, blank out the lvb */
		search_node = dead_node;
	else {
		/* if this is a secondary lockres, and we had no EX or PR
		 * locks granted, we can no longer trust the lvb */
		search_node = dlm->node_num;
		local = 1;  /* check local state for valid lvb */
	}

	for (i=DLM_GRANTED_LIST; i<=DLM_CONVERTING_LIST; i++) {
		queue = dlm_list_idx_to_ptr(res, i);
		list_for_each(iter, queue) {
			lock = list_entry (iter, struct dlm_lock, list);
			if (lock->ml.node == search_node) {
				if (dlm_lvb_needs_invalidation(lock, local)) {
					/* zero the lksb lvb and lockres lvb */
					blank_lvb = 1;
					memset(lock->lksb->lvb, 0, DLM_LVB_LEN);
				}
			}
		}
	}

	if (blank_lvb) {
		mlog(0, "clearing %.*s lvb, dead node %u had EX\n",
		     res->lockname.len, res->lockname.name, dead_node);
		memset(res->lvb, 0, DLM_LVB_LEN);
	}
}

static void dlm_free_dead_locks(struct dlm_ctxt *dlm,
				struct dlm_lock_resource *res, u8 dead_node)
{
	struct list_head *iter, *tmpiter;
	struct dlm_lock *lock;

	/* this node is the lockres master:
	 * 1) remove any stale locks for the dead node
	 * 2) if the dead node had an EX when he died, blank out the lvb 
	 */
	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&res->spinlock);

	/* TODO: check pending_asts, pending_basts here */
	list_for_each_safe(iter, tmpiter, &res->granted) {
		lock = list_entry (iter, struct dlm_lock, list);
		if (lock->ml.node == dead_node) {
			list_del_init(&lock->list);
			dlm_lock_put(lock);
		}
	}
	list_for_each_safe(iter, tmpiter, &res->converting) {
		lock = list_entry (iter, struct dlm_lock, list);
		if (lock->ml.node == dead_node) {
			list_del_init(&lock->list);
			dlm_lock_put(lock);
		}
	}
	list_for_each_safe(iter, tmpiter, &res->blocked) {
		lock = list_entry (iter, struct dlm_lock, list);
		if (lock->ml.node == dead_node) {
			list_del_init(&lock->list);
			dlm_lock_put(lock);
		}
	}

	/* do not kick thread yet */
	__dlm_dirty_lockres(dlm, res);
}

/* if this node is the recovery master, and there are no
 * locks for a given lockres owned by this node that are in
 * either PR or EX mode, zero out the lvb before requesting.
 *
 */


static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node)
{
	struct list_head *iter;
	struct dlm_lock_resource *res;
	int i;
	struct list_head *bucket;
	struct dlm_lock *lock;


	/* purge any stale mles */
	dlm_clean_master_list(dlm, dead_node);

	/*
	 * now clean up all lock resources.  there are two rules:
	 *
	 * 1) if the dead node was the master, move the lockres
	 *    to the recovering list.  set the RECOVERING flag.
	 *    this lockres needs to be cleaned up before it can
	 *    be used further.
	 *
	 * 2) if this node was the master, remove all locks from
	 *    each of the lockres queues that were owned by the
	 *    dead node.  once recovery finishes, the dlm thread
	 *    can be kicked again to see if any ASTs or BASTs
	 *    need to be fired as a result.
	 */
	for (i=0; i<DLM_HASH_SIZE; i++) {
		bucket = &(dlm->resources[i]);
		list_for_each(iter, bucket) {
			res = list_entry (iter, struct dlm_lock_resource, list);
 			/* always prune any $RECOVERY entries for dead nodes,
 			 * otherwise hangs can occur during later recovery */
			if (dlm_is_recovery_lock(res->lockname.name,
						 res->lockname.len)) {
				spin_lock(&res->spinlock);
				list_for_each_entry(lock, &res->granted, list) {
					if (lock->ml.node == dead_node) {
						mlog(0, "AHA! there was "
						     "a $RECOVERY lock for dead "
						     "node %u (%s)!\n",
						     dead_node, dlm->name);
						list_del_init(&lock->list);
						dlm_lock_put(lock);
						break;
					}
				}
				spin_unlock(&res->spinlock);
				continue;
			}			
			spin_lock(&res->spinlock);
			/* zero the lvb if necessary */
			dlm_revalidate_lvb(dlm, res, dead_node);
			if (res->owner == dead_node)
				dlm_move_lockres_to_recovery_list(dlm, res);
			else if (res->owner == dlm->node_num) {
				dlm_free_dead_locks(dlm, res, dead_node);
				__dlm_lockres_calc_usage(dlm, res);
			}
			spin_unlock(&res->spinlock);
		}
	}

}

static void __dlm_hb_node_down(struct dlm_ctxt *dlm, int idx)
{
	assert_spin_locked(&dlm->spinlock);

	/* check to see if the node is already considered dead */
	if (!test_bit(idx, dlm->live_nodes_map)) {
		mlog(0, "for domain %s, node %d is already dead. "
		     "another node likely did recovery already.\n",
		     dlm->name, idx);
		return;
	}

	/* check to see if we do not care about this node */
	if (!test_bit(idx, dlm->domain_map)) {
		/* This also catches the case that we get a node down
		 * but haven't joined the domain yet. */
		mlog(0, "node %u already removed from domain!\n", idx);
		return;
	}

	clear_bit(idx, dlm->live_nodes_map);

	/* Clean up join state on node death. */
	if (dlm->joining_node == idx) {
		mlog(0, "Clearing join state for node %u\n", idx);
		__dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
	}

	/* make sure local cleanup occurs before the heartbeat events */
	if (!test_bit(idx, dlm->recovery_map))
		dlm_do_local_recovery_cleanup(dlm, idx);

	/* notify anything attached to the heartbeat events */
	dlm_hb_event_notify_attached(dlm, idx, 0);

	mlog(0, "node %u being removed from domain map!\n", idx);
	clear_bit(idx, dlm->domain_map);
	/* wake up migration waiters if a node goes down.
	 * perhaps later we can genericize this for other waiters. */
	wake_up(&dlm->migration_wq);

	if (test_bit(idx, dlm->recovery_map))
		mlog(0, "domain %s, node %u already added "
		     "to recovery map!\n", dlm->name, idx);
	else
		set_bit(idx, dlm->recovery_map);
}

void dlm_hb_node_down_cb(struct o2nm_node *node, int idx, void *data)
{
	struct dlm_ctxt *dlm = data;

	if (!dlm_grab(dlm))
		return;

	spin_lock(&dlm->spinlock);
	__dlm_hb_node_down(dlm, idx);
	spin_unlock(&dlm->spinlock);

	dlm_put(dlm);
}

void dlm_hb_node_up_cb(struct o2nm_node *node, int idx, void *data)
{
	struct dlm_ctxt *dlm = data;

	if (!dlm_grab(dlm))
		return;

	spin_lock(&dlm->spinlock);
	set_bit(idx, dlm->live_nodes_map);
	/* do NOT notify mle attached to the heartbeat events.
	 * new nodes are not interesting in mastery until joined. */
	spin_unlock(&dlm->spinlock);

	dlm_put(dlm);
}

static void dlm_reco_ast(void *astdata)
{
	struct dlm_ctxt *dlm = astdata;
	mlog(0, "ast for recovery lock fired!, this=%u, dlm=%s\n",
	     dlm->node_num, dlm->name);
}
static void dlm_reco_bast(void *astdata, int blocked_type)
{
	struct dlm_ctxt *dlm = astdata;
	mlog(0, "bast for recovery lock fired!, this=%u, dlm=%s\n",
	     dlm->node_num, dlm->name);
}
static void dlm_reco_unlock_ast(void *astdata, enum dlm_status st)
{
	mlog(0, "unlockast for recovery lock fired!\n");
}

/*
 * dlm_pick_recovery_master will continually attempt to use
 * dlmlock() on the special "$RECOVERY" lockres with the
 * LKM_NOQUEUE flag to get an EX.  every thread that enters
 * this function on each node racing to become the recovery
 * master will not stop attempting this until either:
 * a) this node gets the EX (and becomes the recovery master),
 * or b) dlm->reco.new_master gets set to some nodenum 
 * != O2NM_INVALID_NODE_NUM (another node will do the reco).
 * so each time a recovery master is needed, the entire cluster
 * will sync at this point.  if the new master dies, that will
 * be detected in dlm_do_recovery */
static int dlm_pick_recovery_master(struct dlm_ctxt *dlm)
{
	enum dlm_status ret;
	struct dlm_lockstatus lksb;
	int status = -EINVAL;

	mlog(0, "starting recovery of %s at %lu, dead=%u, this=%u\n",
	     dlm->name, jiffies, dlm->reco.dead_node, dlm->node_num);
again:	
	memset(&lksb, 0, sizeof(lksb));

	ret = dlmlock(dlm, LKM_EXMODE, &lksb, LKM_NOQUEUE|LKM_RECOVERY,
		      DLM_RECOVERY_LOCK_NAME, dlm_reco_ast, dlm, dlm_reco_bast);

	mlog(0, "%s: dlmlock($RECOVERY) returned %d, lksb=%d\n",
	     dlm->name, ret, lksb.status);

	if (ret == DLM_NORMAL) {
		mlog(0, "dlm=%s dlmlock says I got it (this=%u)\n",
		     dlm->name, dlm->node_num);
		
		/* got the EX lock.  check to see if another node 
		 * just became the reco master */
		if (dlm_reco_master_ready(dlm)) {
			mlog(0, "%s: got reco EX lock, but %u will "
			     "do the recovery\n", dlm->name,
			     dlm->reco.new_master);
			status = -EEXIST;
		} else {
			status = 0;

			/* see if recovery was already finished elsewhere */
			spin_lock(&dlm->spinlock);
			if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
				status = -EINVAL;	
				mlog(0, "%s: got reco EX lock, but "
				     "node got recovered already\n", dlm->name);
				if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM) {
					mlog(ML_ERROR, "%s: new master is %u "
					     "but no dead node!\n", 
					     dlm->name, dlm->reco.new_master);
					BUG();
				}
			}
			spin_unlock(&dlm->spinlock);
		}

		/* if this node has actually become the recovery master,
		 * set the master and send the messages to begin recovery */
		if (!status) {
			mlog(0, "%s: dead=%u, this=%u, sending "
			     "begin_reco now\n", dlm->name, 
			     dlm->reco.dead_node, dlm->node_num);
			status = dlm_send_begin_reco_message(dlm,
				      dlm->reco.dead_node);
			/* this always succeeds */
			BUG_ON(status);

			/* set the new_master to this node */
			spin_lock(&dlm->spinlock);
			dlm->reco.new_master = dlm->node_num;
			spin_unlock(&dlm->spinlock);
		}

		/* recovery lock is a special case.  ast will not get fired,
		 * so just go ahead and unlock it. */
		ret = dlmunlock(dlm, &lksb, 0, dlm_reco_unlock_ast, dlm);
		if (ret == DLM_DENIED) {
			mlog(0, "got DLM_DENIED, trying LKM_CANCEL\n");
			ret = dlmunlock(dlm, &lksb, LKM_CANCEL, dlm_reco_unlock_ast, dlm);
		}
		if (ret != DLM_NORMAL) {
			/* this would really suck. this could only happen
			 * if there was a network error during the unlock
			 * because of node death.  this means the unlock
			 * is actually "done" and the lock structure is
			 * even freed.  we can continue, but only
			 * because this specific lock name is special. */
			mlog(ML_ERROR, "dlmunlock returned %d\n", ret);
		}
	} else if (ret == DLM_NOTQUEUED) {
		mlog(0, "dlm=%s dlmlock says another node got it (this=%u)\n",
		     dlm->name, dlm->node_num);
		/* another node is master. wait on
		 * reco.new_master != O2NM_INVALID_NODE_NUM 
		 * for at most one second */
		wait_event_timeout(dlm->dlm_reco_thread_wq,
					 dlm_reco_master_ready(dlm),
					 msecs_to_jiffies(1000));
		if (!dlm_reco_master_ready(dlm)) {
			mlog(0, "%s: reco master taking awhile\n",
			     dlm->name);
			goto again;
		}
		/* another node has informed this one that it is reco master */
		mlog(0, "%s: reco master %u is ready to recover %u\n",
		     dlm->name, dlm->reco.new_master, dlm->reco.dead_node);
		status = -EEXIST;
	} else {
		struct dlm_lock_resource *res;

		/* dlmlock returned something other than NOTQUEUED or NORMAL */
		mlog(ML_ERROR, "%s: got %s from dlmlock($RECOVERY), "
		     "lksb.status=%s\n", dlm->name, dlm_errname(ret),
		     dlm_errname(lksb.status));
		res = dlm_lookup_lockres(dlm, DLM_RECOVERY_LOCK_NAME,
					 DLM_RECOVERY_LOCK_NAME_LEN);
		if (res) {
			dlm_print_one_lock_resource(res);
			dlm_lockres_put(res);
		} else {
			mlog(ML_ERROR, "recovery lock not found\n");
		}
		BUG();
	}

	return status;
}

static int dlm_send_begin_reco_message(struct dlm_ctxt *dlm, u8 dead_node)
{
	struct dlm_begin_reco br;
	int ret = 0;
	struct dlm_node_iter iter;
	int nodenum;
	int status;

	mlog_entry("%u\n", dead_node);

	mlog(0, "dead node is %u\n", dead_node);

	spin_lock(&dlm->spinlock);
	dlm_node_iter_init(dlm->domain_map, &iter);
	spin_unlock(&dlm->spinlock);

	clear_bit(dead_node, iter.node_map);

	memset(&br, 0, sizeof(br));
	br.node_idx = dlm->node_num;
	br.dead_node = dead_node;

	while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
		ret = 0;
		if (nodenum == dead_node) {
			mlog(0, "not sending begin reco to dead node "
				  "%u\n", dead_node);
			continue;
		}
		if (nodenum == dlm->node_num) {
			mlog(0, "not sending begin reco to self\n");
			continue;
		}
retry:
		ret = -EINVAL;
		mlog(0, "attempting to send begin reco msg to %d\n",
			  nodenum);
		ret = o2net_send_message(DLM_BEGIN_RECO_MSG, dlm->key,
					 &br, sizeof(br), nodenum, &status);
		/* negative status is handled ok by caller here */
		if (ret >= 0)
			ret = status;
		if (dlm_is_host_down(ret)) {
			/* node is down.  not involved in recovery
			 * so just keep going */
			mlog(0, "%s: node %u was down when sending "
			     "begin reco msg (%d)\n", dlm->name, nodenum, ret);
			ret = 0;
		}
		if (ret < 0) {
			struct dlm_lock_resource *res;
			/* this is now a serious problem, possibly ENOMEM 
			 * in the network stack.  must retry */
			mlog_errno(ret);
			mlog(ML_ERROR, "begin reco of dlm %s to node %u "
			    " returned %d\n", dlm->name, nodenum, ret);
			res = dlm_lookup_lockres(dlm, DLM_RECOVERY_LOCK_NAME,
						 DLM_RECOVERY_LOCK_NAME_LEN);
			if (res) {
				dlm_print_one_lock_resource(res);
				dlm_lockres_put(res);
			} else {
				mlog(ML_ERROR, "recovery lock not found\n");
			}
			/* sleep for a bit in hopes that we can avoid 
			 * another ENOMEM */
			msleep(100);
			goto retry;
		}
	}

	return ret;
}

int dlm_begin_reco_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_begin_reco *br = (struct dlm_begin_reco *)msg->buf;

	/* ok to return 0, domain has gone away */
	if (!dlm_grab(dlm))
		return 0;

	mlog(0, "node %u wants to recover node %u\n",
		  br->node_idx, br->dead_node);

	dlm_fire_domain_eviction_callbacks(dlm, br->dead_node);

	spin_lock(&dlm->spinlock);
	if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM) {
		if (test_bit(dlm->reco.new_master, dlm->recovery_map)) {
			mlog(0, "%s: new_master %u died, changing "
			     "to %u\n", dlm->name, dlm->reco.new_master,
			     br->node_idx);
		} else {
			mlog(0, "%s: new_master %u NOT DEAD, changing "
			     "to %u\n", dlm->name, dlm->reco.new_master,
			     br->node_idx);
			/* may not have seen the new master as dead yet */
		}
	}
	if (dlm->reco.dead_node != O2NM_INVALID_NODE_NUM) {
		mlog(ML_NOTICE, "%s: dead_node previously set to %u, "
		     "node %u changing it to %u\n", dlm->name, 
		     dlm->reco.dead_node, br->node_idx, br->dead_node);
	}
	dlm->reco.new_master = br->node_idx;
	dlm->reco.dead_node = br->dead_node;
	if (!test_bit(br->dead_node, dlm->recovery_map)) {
		mlog(0, "recovery master %u sees %u as dead, but this "
		     "node has not yet.  marking %u as dead\n",
		     br->node_idx, br->dead_node, br->dead_node);
		if (!test_bit(br->dead_node, dlm->domain_map) ||
		    !test_bit(br->dead_node, dlm->live_nodes_map))
			mlog(0, "%u not in domain/live_nodes map "
			     "so setting it in reco map manually\n",
			     br->dead_node);
		set_bit(br->dead_node, dlm->recovery_map);
		__dlm_hb_node_down(dlm, br->dead_node);
	}
	spin_unlock(&dlm->spinlock);

	dlm_kick_recovery_thread(dlm);
	dlm_put(dlm);
	return 0;
}

static int dlm_send_finalize_reco_message(struct dlm_ctxt *dlm)
{
	int ret = 0;
	struct dlm_finalize_reco fr;
	struct dlm_node_iter iter;
	int nodenum;
	int status;

	mlog(0, "finishing recovery for node %s:%u\n",
	     dlm->name, dlm->reco.dead_node);

	spin_lock(&dlm->spinlock);
	dlm_node_iter_init(dlm->domain_map, &iter);
	spin_unlock(&dlm->spinlock);

	memset(&fr, 0, sizeof(fr));
	fr.node_idx = dlm->node_num;
	fr.dead_node = dlm->reco.dead_node;

	while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
		if (nodenum == dlm->node_num)
			continue;
		ret = o2net_send_message(DLM_FINALIZE_RECO_MSG, dlm->key,
					 &fr, sizeof(fr), nodenum, &status);
		if (ret >= 0) {
			ret = status;
			if (dlm_is_host_down(ret)) {
				/* this has no effect on this recovery 
				 * session, so set the status to zero to 
				 * finish out the last recovery */
				mlog(ML_ERROR, "node %u went down after this "
				     "node finished recovery.\n", nodenum);
				ret = 0;
			}
		}
		if (ret < 0) {
			mlog_errno(ret);
			break;
		}
	}

	return ret;
}

int dlm_finalize_reco_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_finalize_reco *fr = (struct dlm_finalize_reco *)msg->buf;

	/* ok to return 0, domain has gone away */
	if (!dlm_grab(dlm))
		return 0;

	mlog(0, "node %u finalizing recovery of node %u\n",
	     fr->node_idx, fr->dead_node);

	spin_lock(&dlm->spinlock);

	if (dlm->reco.new_master != fr->node_idx) {
		mlog(ML_ERROR, "node %u sent recovery finalize msg, but node "
		     "%u is supposed to be the new master, dead=%u\n",
		     fr->node_idx, dlm->reco.new_master, fr->dead_node);
		BUG();
	}
	if (dlm->reco.dead_node != fr->dead_node) {
		mlog(ML_ERROR, "node %u sent recovery finalize msg for dead "
		     "node %u, but node %u is supposed to be dead\n",
		     fr->node_idx, fr->dead_node, dlm->reco.dead_node);
		BUG();
	}

	dlm_finish_local_lockres_recovery(dlm, fr->dead_node, fr->node_idx);

	spin_unlock(&dlm->spinlock);

	dlm_reset_recovery(dlm);

	dlm_kick_recovery_thread(dlm);
	dlm_put(dlm);
	return 0;
}