aboutsummaryrefslogtreecommitdiff
path: root/fs/dlm/lock.c
blob: 7bc6ad9299a28637052c1f18bb71c60cef7843b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
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
1263
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
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
/******************************************************************************
*******************************************************************************
**
**  Copyright (C) 2005-2007 Red Hat, Inc.  All rights reserved.
**
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/

/* Central locking logic has four stages:

   dlm_lock()
   dlm_unlock()

   request_lock(ls, lkb)
   convert_lock(ls, lkb)
   unlock_lock(ls, lkb)
   cancel_lock(ls, lkb)

   _request_lock(r, lkb)
   _convert_lock(r, lkb)
   _unlock_lock(r, lkb)
   _cancel_lock(r, lkb)

   do_request(r, lkb)
   do_convert(r, lkb)
   do_unlock(r, lkb)
   do_cancel(r, lkb)

   Stage 1 (lock, unlock) is mainly about checking input args and
   splitting into one of the four main operations:

       dlm_lock          = request_lock
       dlm_lock+CONVERT  = convert_lock
       dlm_unlock        = unlock_lock
       dlm_unlock+CANCEL = cancel_lock

   Stage 2, xxxx_lock(), just finds and locks the relevant rsb which is
   provided to the next stage.

   Stage 3, _xxxx_lock(), determines if the operation is local or remote.
   When remote, it calls send_xxxx(), when local it calls do_xxxx().

   Stage 4, do_xxxx(), is the guts of the operation.  It manipulates the
   given rsb and lkb and queues callbacks.

   For remote operations, send_xxxx() results in the corresponding do_xxxx()
   function being executed on the remote node.  The connecting send/receive
   calls on local (L) and remote (R) nodes:

   L: send_xxxx()              ->  R: receive_xxxx()
                                   R: do_xxxx()
   L: receive_xxxx_reply()     <-  R: send_xxxx_reply()
*/
#include <linux/types.h>
#include "dlm_internal.h"
#include <linux/dlm_device.h>
#include "memory.h"
#include "lowcomms.h"
#include "requestqueue.h"
#include "util.h"
#include "dir.h"
#include "member.h"
#include "lockspace.h"
#include "ast.h"
#include "lock.h"
#include "rcom.h"
#include "recover.h"
#include "lvb_table.h"
#include "user.h"
#include "config.h"

static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode);
static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_remove(struct dlm_rsb *r);
static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
				    struct dlm_message *ms);
static int receive_extralen(struct dlm_message *ms);
static void do_purge(struct dlm_ls *ls, int nodeid, int pid);
static void del_timeout(struct dlm_lkb *lkb);

/*
 * Lock compatibilty matrix - thanks Steve
 * UN = Unlocked state. Not really a state, used as a flag
 * PD = Padding. Used to make the matrix a nice power of two in size
 * Other states are the same as the VMS DLM.
 * Usage: matrix[grmode+1][rqmode+1]  (although m[rq+1][gr+1] is the same)
 */

static const int __dlm_compat_matrix[8][8] = {
      /* UN NL CR CW PR PW EX PD */
        {1, 1, 1, 1, 1, 1, 1, 0},       /* UN */
        {1, 1, 1, 1, 1, 1, 1, 0},       /* NL */
        {1, 1, 1, 1, 1, 1, 0, 0},       /* CR */
        {1, 1, 1, 1, 0, 0, 0, 0},       /* CW */
        {1, 1, 1, 0, 1, 0, 0, 0},       /* PR */
        {1, 1, 1, 0, 0, 0, 0, 0},       /* PW */
        {1, 1, 0, 0, 0, 0, 0, 0},       /* EX */
        {0, 0, 0, 0, 0, 0, 0, 0}        /* PD */
};

/*
 * This defines the direction of transfer of LVB data.
 * Granted mode is the row; requested mode is the column.
 * Usage: matrix[grmode+1][rqmode+1]
 * 1 = LVB is returned to the caller
 * 0 = LVB is written to the resource
 * -1 = nothing happens to the LVB
 */

const int dlm_lvb_operations[8][8] = {
        /* UN   NL  CR  CW  PR  PW  EX  PD*/
        {  -1,  1,  1,  1,  1,  1,  1, -1 }, /* UN */
        {  -1,  1,  1,  1,  1,  1,  1,  0 }, /* NL */
        {  -1, -1,  1,  1,  1,  1,  1,  0 }, /* CR */
        {  -1, -1, -1,  1,  1,  1,  1,  0 }, /* CW */
        {  -1, -1, -1, -1,  1,  1,  1,  0 }, /* PR */
        {  -1,  0,  0,  0,  0,  0,  1,  0 }, /* PW */
        {  -1,  0,  0,  0,  0,  0,  0,  0 }, /* EX */
        {  -1,  0,  0,  0,  0,  0,  0,  0 }  /* PD */
};

#define modes_compat(gr, rq) \
	__dlm_compat_matrix[(gr)->lkb_grmode + 1][(rq)->lkb_rqmode + 1]

int dlm_modes_compat(int mode1, int mode2)
{
	return __dlm_compat_matrix[mode1 + 1][mode2 + 1];
}

/*
 * Compatibility matrix for conversions with QUECVT set.
 * Granted mode is the row; requested mode is the column.
 * Usage: matrix[grmode+1][rqmode+1]
 */

static const int __quecvt_compat_matrix[8][8] = {
      /* UN NL CR CW PR PW EX PD */
        {0, 0, 0, 0, 0, 0, 0, 0},       /* UN */
        {0, 0, 1, 1, 1, 1, 1, 0},       /* NL */
        {0, 0, 0, 1, 1, 1, 1, 0},       /* CR */
        {0, 0, 0, 0, 1, 1, 1, 0},       /* CW */
        {0, 0, 0, 1, 0, 1, 1, 0},       /* PR */
        {0, 0, 0, 0, 0, 0, 1, 0},       /* PW */
        {0, 0, 0, 0, 0, 0, 0, 0},       /* EX */
        {0, 0, 0, 0, 0, 0, 0, 0}        /* PD */
};

void dlm_print_lkb(struct dlm_lkb *lkb)
{
	printk(KERN_ERR "lkb: nodeid %d id %x remid %x exflags %x flags %x\n"
	       "     status %d rqmode %d grmode %d wait_type %d ast_type %d\n",
	       lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags,
	       lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode,
	       lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_ast_type);
}

void dlm_print_rsb(struct dlm_rsb *r)
{
	printk(KERN_ERR "rsb: nodeid %d flags %lx first %x rlc %d name %s\n",
	       r->res_nodeid, r->res_flags, r->res_first_lkid,
	       r->res_recover_locks_count, r->res_name);
}

void dlm_dump_rsb(struct dlm_rsb *r)
{
	struct dlm_lkb *lkb;

	dlm_print_rsb(r);

	printk(KERN_ERR "rsb: root_list empty %d recover_list empty %d\n",
	       list_empty(&r->res_root_list), list_empty(&r->res_recover_list));
	printk(KERN_ERR "rsb lookup list\n");
	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup)
		dlm_print_lkb(lkb);
	printk(KERN_ERR "rsb grant queue:\n");
	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue)
		dlm_print_lkb(lkb);
	printk(KERN_ERR "rsb convert queue:\n");
	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue)
		dlm_print_lkb(lkb);
	printk(KERN_ERR "rsb wait queue:\n");
	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue)
		dlm_print_lkb(lkb);
}

/* Threads cannot use the lockspace while it's being recovered */

static inline void dlm_lock_recovery(struct dlm_ls *ls)
{
	down_read(&ls->ls_in_recovery);
}

void dlm_unlock_recovery(struct dlm_ls *ls)
{
	up_read(&ls->ls_in_recovery);
}

int dlm_lock_recovery_try(struct dlm_ls *ls)
{
	return down_read_trylock(&ls->ls_in_recovery);
}

static inline int can_be_queued(struct dlm_lkb *lkb)
{
	return !(lkb->lkb_exflags & DLM_LKF_NOQUEUE);
}

static inline int force_blocking_asts(struct dlm_lkb *lkb)
{
	return (lkb->lkb_exflags & DLM_LKF_NOQUEUEBAST);
}

static inline int is_demoted(struct dlm_lkb *lkb)
{
	return (lkb->lkb_sbflags & DLM_SBF_DEMOTED);
}

static inline int is_altmode(struct dlm_lkb *lkb)
{
	return (lkb->lkb_sbflags & DLM_SBF_ALTMODE);
}

static inline int is_granted(struct dlm_lkb *lkb)
{
	return (lkb->lkb_status == DLM_LKSTS_GRANTED);
}

static inline int is_remote(struct dlm_rsb *r)
{
	DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r););
	return !!r->res_nodeid;
}

static inline int is_process_copy(struct dlm_lkb *lkb)
{
	return (lkb->lkb_nodeid && !(lkb->lkb_flags & DLM_IFL_MSTCPY));
}

static inline int is_master_copy(struct dlm_lkb *lkb)
{
	if (lkb->lkb_flags & DLM_IFL_MSTCPY)
		DLM_ASSERT(lkb->lkb_nodeid, dlm_print_lkb(lkb););
	return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? 1 : 0;
}

static inline int middle_conversion(struct dlm_lkb *lkb)
{
	if ((lkb->lkb_grmode==DLM_LOCK_PR && lkb->lkb_rqmode==DLM_LOCK_CW) ||
	    (lkb->lkb_rqmode==DLM_LOCK_PR && lkb->lkb_grmode==DLM_LOCK_CW))
		return 1;
	return 0;
}

static inline int down_conversion(struct dlm_lkb *lkb)
{
	return (!middle_conversion(lkb) && lkb->lkb_rqmode < lkb->lkb_grmode);
}

static inline int is_overlap_unlock(struct dlm_lkb *lkb)
{
	return lkb->lkb_flags & DLM_IFL_OVERLAP_UNLOCK;
}

static inline int is_overlap_cancel(struct dlm_lkb *lkb)
{
	return lkb->lkb_flags & DLM_IFL_OVERLAP_CANCEL;
}

static inline int is_overlap(struct dlm_lkb *lkb)
{
	return (lkb->lkb_flags & (DLM_IFL_OVERLAP_UNLOCK |
				  DLM_IFL_OVERLAP_CANCEL));
}

static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
	if (is_master_copy(lkb))
		return;

	del_timeout(lkb);

	DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb););

	/* if the operation was a cancel, then return -DLM_ECANCEL, if a
	   timeout caused the cancel then return -ETIMEDOUT */
	if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_TIMEOUT_CANCEL)) {
		lkb->lkb_flags &= ~DLM_IFL_TIMEOUT_CANCEL;
		rv = -ETIMEDOUT;
	}

	if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_DEADLOCK_CANCEL)) {
		lkb->lkb_flags &= ~DLM_IFL_DEADLOCK_CANCEL;
		rv = -EDEADLK;
	}

	lkb->lkb_lksb->sb_status = rv;
	lkb->lkb_lksb->sb_flags = lkb->lkb_sbflags;

	dlm_add_ast(lkb, AST_COMP);
}

static inline void queue_cast_overlap(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	queue_cast(r, lkb,
		   is_overlap_unlock(lkb) ? -DLM_EUNLOCK : -DLM_ECANCEL);
}

static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
{
	if (is_master_copy(lkb))
		send_bast(r, lkb, rqmode);
	else {
		lkb->lkb_bastmode = rqmode;
		dlm_add_ast(lkb, AST_BAST);
	}
}

/*
 * Basic operations on rsb's and lkb's
 */

static struct dlm_rsb *create_rsb(struct dlm_ls *ls, char *name, int len)
{
	struct dlm_rsb *r;

	r = allocate_rsb(ls, len);
	if (!r)
		return NULL;

	r->res_ls = ls;
	r->res_length = len;
	memcpy(r->res_name, name, len);
	mutex_init(&r->res_mutex);

	INIT_LIST_HEAD(&r->res_lookup);
	INIT_LIST_HEAD(&r->res_grantqueue);
	INIT_LIST_HEAD(&r->res_convertqueue);
	INIT_LIST_HEAD(&r->res_waitqueue);
	INIT_LIST_HEAD(&r->res_root_list);
	INIT_LIST_HEAD(&r->res_recover_list);

	return r;
}

static int search_rsb_list(struct list_head *head, char *name, int len,
			   unsigned int flags, struct dlm_rsb **r_ret)
{
	struct dlm_rsb *r;
	int error = 0;

	list_for_each_entry(r, head, res_hashchain) {
		if (len == r->res_length && !memcmp(name, r->res_name, len))
			goto found;
	}
	return -EBADR;

 found:
	if (r->res_nodeid && (flags & R_MASTER))
		error = -ENOTBLK;
	*r_ret = r;
	return error;
}

static int _search_rsb(struct dlm_ls *ls, char *name, int len, int b,
		       unsigned int flags, struct dlm_rsb **r_ret)
{
	struct dlm_rsb *r;
	int error;

	error = search_rsb_list(&ls->ls_rsbtbl[b].list, name, len, flags, &r);
	if (!error) {
		kref_get(&r->res_ref);
		goto out;
	}
	error = search_rsb_list(&ls->ls_rsbtbl[b].toss, name, len, flags, &r);
	if (error)
		goto out;

	list_move(&r->res_hashchain, &ls->ls_rsbtbl[b].list);

	if (dlm_no_directory(ls))
		goto out;

	if (r->res_nodeid == -1) {
		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
		r->res_first_lkid = 0;
	} else if (r->res_nodeid > 0) {
		rsb_set_flag(r, RSB_MASTER_UNCERTAIN);
		r->res_first_lkid = 0;
	} else {
		DLM_ASSERT(r->res_nodeid == 0, dlm_print_rsb(r););
		DLM_ASSERT(!rsb_flag(r, RSB_MASTER_UNCERTAIN),);
	}
 out:
	*r_ret = r;
	return error;
}

static int search_rsb(struct dlm_ls *ls, char *name, int len, int b,
		      unsigned int flags, struct dlm_rsb **r_ret)
{
	int error;
	write_lock(&ls->ls_rsbtbl[b].lock);
	error = _search_rsb(ls, name, len, b, flags, r_ret);
	write_unlock(&ls->ls_rsbtbl[b].lock);
	return error;
}

/*
 * Find rsb in rsbtbl and potentially create/add one
 *
 * Delaying the release of rsb's has a similar benefit to applications keeping
 * NL locks on an rsb, but without the guarantee that the cached master value
 * will still be valid when the rsb is reused.  Apps aren't always smart enough
 * to keep NL locks on an rsb that they may lock again shortly; this can lead
 * to excessive master lookups and removals if we don't delay the release.
 *
 * Searching for an rsb means looking through both the normal list and toss
 * list.  When found on the toss list the rsb is moved to the normal list with
 * ref count of 1; when found on normal list the ref count is incremented.
 */

static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
		    unsigned int flags, struct dlm_rsb **r_ret)
{
	struct dlm_rsb *r, *tmp;
	uint32_t hash, bucket;
	int error = 0;

	if (dlm_no_directory(ls))
		flags |= R_CREATE;

	hash = jhash(name, namelen, 0);
	bucket = hash & (ls->ls_rsbtbl_size - 1);

	error = search_rsb(ls, name, namelen, bucket, flags, &r);
	if (!error)
		goto out;

	if (error == -EBADR && !(flags & R_CREATE))
		goto out;

	/* the rsb was found but wasn't a master copy */
	if (error == -ENOTBLK)
		goto out;

	error = -ENOMEM;
	r = create_rsb(ls, name, namelen);
	if (!r)
		goto out;

	r->res_hash = hash;
	r->res_bucket = bucket;
	r->res_nodeid = -1;
	kref_init(&r->res_ref);

	/* With no directory, the master can be set immediately */
	if (dlm_no_directory(ls)) {
		int nodeid = dlm_dir_nodeid(r);
		if (nodeid == dlm_our_nodeid())
			nodeid = 0;
		r->res_nodeid = nodeid;
	}

	write_lock(&ls->ls_rsbtbl[bucket].lock);
	error = _search_rsb(ls, name, namelen, bucket, 0, &tmp);
	if (!error) {
		write_unlock(&ls->ls_rsbtbl[bucket].lock);
		free_rsb(r);
		r = tmp;
		goto out;
	}
	list_add(&r->res_hashchain, &ls->ls_rsbtbl[bucket].list);
	write_unlock(&ls->ls_rsbtbl[bucket].lock);
	error = 0;
 out:
	*r_ret = r;
	return error;
}

int dlm_find_rsb(struct dlm_ls *ls, char *name, int namelen,
		 unsigned int flags, struct dlm_rsb **r_ret)
{
	return find_rsb(ls, name, namelen, flags, r_ret);
}

/* This is only called to add a reference when the code already holds
   a valid reference to the rsb, so there's no need for locking. */

static inline void hold_rsb(struct dlm_rsb *r)
{
	kref_get(&r->res_ref);
}

void dlm_hold_rsb(struct dlm_rsb *r)
{
	hold_rsb(r);
}

static void toss_rsb(struct kref *kref)
{
	struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref);
	struct dlm_ls *ls = r->res_ls;

	DLM_ASSERT(list_empty(&r->res_root_list), dlm_print_rsb(r););
	kref_init(&r->res_ref);
	list_move(&r->res_hashchain, &ls->ls_rsbtbl[r->res_bucket].toss);
	r->res_toss_time = jiffies;
	if (r->res_lvbptr) {
		free_lvb(r->res_lvbptr);
		r->res_lvbptr = NULL;
	}
}

/* When all references to the rsb are gone it's transfered to
   the tossed list for later disposal. */

static void put_rsb(struct dlm_rsb *r)
{
	struct dlm_ls *ls = r->res_ls;
	uint32_t bucket = r->res_bucket;

	write_lock(&ls->ls_rsbtbl[bucket].lock);
	kref_put(&r->res_ref, toss_rsb);
	write_unlock(&ls->ls_rsbtbl[bucket].lock);
}

void dlm_put_rsb(struct dlm_rsb *r)
{
	put_rsb(r);
}

/* See comment for unhold_lkb */

static void unhold_rsb(struct dlm_rsb *r)
{
	int rv;
	rv = kref_put(&r->res_ref, toss_rsb);
	DLM_ASSERT(!rv, dlm_dump_rsb(r););
}

static void kill_rsb(struct kref *kref)
{
	struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref);

	/* All work is done after the return from kref_put() so we
	   can release the write_lock before the remove and free. */

	DLM_ASSERT(list_empty(&r->res_lookup), dlm_dump_rsb(r););
	DLM_ASSERT(list_empty(&r->res_grantqueue), dlm_dump_rsb(r););
	DLM_ASSERT(list_empty(&r->res_convertqueue), dlm_dump_rsb(r););
	DLM_ASSERT(list_empty(&r->res_waitqueue), dlm_dump_rsb(r););
	DLM_ASSERT(list_empty(&r->res_root_list), dlm_dump_rsb(r););
	DLM_ASSERT(list_empty(&r->res_recover_list), dlm_dump_rsb(r););
}

/* Attaching/detaching lkb's from rsb's is for rsb reference counting.
   The rsb must exist as long as any lkb's for it do. */

static void attach_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	hold_rsb(r);
	lkb->lkb_resource = r;
}

static void detach_lkb(struct dlm_lkb *lkb)
{
	if (lkb->lkb_resource) {
		put_rsb(lkb->lkb_resource);
		lkb->lkb_resource = NULL;
	}
}

static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
{
	struct dlm_lkb *lkb, *tmp;
	uint32_t lkid = 0;
	uint16_t bucket;

	lkb = allocate_lkb(ls);
	if (!lkb)
		return -ENOMEM;

	lkb->lkb_nodeid = -1;
	lkb->lkb_grmode = DLM_LOCK_IV;
	kref_init(&lkb->lkb_ref);
	INIT_LIST_HEAD(&lkb->lkb_ownqueue);
	INIT_LIST_HEAD(&lkb->lkb_rsb_lookup);
	INIT_LIST_HEAD(&lkb->lkb_time_list);

	get_random_bytes(&bucket, sizeof(bucket));
	bucket &= (ls->ls_lkbtbl_size - 1);

	write_lock(&ls->ls_lkbtbl[bucket].lock);

	/* counter can roll over so we must verify lkid is not in use */

	while (lkid == 0) {
		lkid = (bucket << 16) | ls->ls_lkbtbl[bucket].counter++;

		list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list,
				    lkb_idtbl_list) {
			if (tmp->lkb_id != lkid)
				continue;
			lkid = 0;
			break;
		}
	}

	lkb->lkb_id = lkid;
	list_add(&lkb->lkb_idtbl_list, &ls->ls_lkbtbl[bucket].list);
	write_unlock(&ls->ls_lkbtbl[bucket].lock);

	*lkb_ret = lkb;
	return 0;
}

static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid)
{
	struct dlm_lkb *lkb;
	uint16_t bucket = (lkid >> 16);

	list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) {
		if (lkb->lkb_id == lkid)
			return lkb;
	}
	return NULL;
}

static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret)
{
	struct dlm_lkb *lkb;
	uint16_t bucket = (lkid >> 16);

	if (bucket >= ls->ls_lkbtbl_size)
		return -EBADSLT;

	read_lock(&ls->ls_lkbtbl[bucket].lock);
	lkb = __find_lkb(ls, lkid);
	if (lkb)
		kref_get(&lkb->lkb_ref);
	read_unlock(&ls->ls_lkbtbl[bucket].lock);

	*lkb_ret = lkb;
	return lkb ? 0 : -ENOENT;
}

static void kill_lkb(struct kref *kref)
{
	struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref);

	/* All work is done after the return from kref_put() so we
	   can release the write_lock before the detach_lkb */

	DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););
}

/* __put_lkb() is used when an lkb may not have an rsb attached to
   it so we need to provide the lockspace explicitly */

static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	uint16_t bucket = (lkb->lkb_id >> 16);

	write_lock(&ls->ls_lkbtbl[bucket].lock);
	if (kref_put(&lkb->lkb_ref, kill_lkb)) {
		list_del(&lkb->lkb_idtbl_list);
		write_unlock(&ls->ls_lkbtbl[bucket].lock);

		detach_lkb(lkb);

		/* for local/process lkbs, lvbptr points to caller's lksb */
		if (lkb->lkb_lvbptr && is_master_copy(lkb))
			free_lvb(lkb->lkb_lvbptr);
		free_lkb(lkb);
		return 1;
	} else {
		write_unlock(&ls->ls_lkbtbl[bucket].lock);
		return 0;
	}
}

int dlm_put_lkb(struct dlm_lkb *lkb)
{
	struct dlm_ls *ls;

	DLM_ASSERT(lkb->lkb_resource, dlm_print_lkb(lkb););
	DLM_ASSERT(lkb->lkb_resource->res_ls, dlm_print_lkb(lkb););

	ls = lkb->lkb_resource->res_ls;
	return __put_lkb(ls, lkb);
}

/* This is only called to add a reference when the code already holds
   a valid reference to the lkb, so there's no need for locking. */

static inline void hold_lkb(struct dlm_lkb *lkb)
{
	kref_get(&lkb->lkb_ref);
}

/* This is called when we need to remove a reference and are certain
   it's not the last ref.  e.g. del_lkb is always called between a
   find_lkb/put_lkb and is always the inverse of a previous add_lkb.
   put_lkb would work fine, but would involve unnecessary locking */

static inline void unhold_lkb(struct dlm_lkb *lkb)
{
	int rv;
	rv = kref_put(&lkb->lkb_ref, kill_lkb);
	DLM_ASSERT(!rv, dlm_print_lkb(lkb););
}

static void lkb_add_ordered(struct list_head *new, struct list_head *head,
			    int mode)
{
	struct dlm_lkb *lkb = NULL;

	list_for_each_entry(lkb, head, lkb_statequeue)
		if (lkb->lkb_rqmode < mode)
			break;

	if (!lkb)
		list_add_tail(new, head);
	else
		__list_add(new, lkb->lkb_statequeue.prev, &lkb->lkb_statequeue);
}

/* add/remove lkb to rsb's grant/convert/wait queue */

static void add_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int status)
{
	kref_get(&lkb->lkb_ref);

	DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););

	lkb->lkb_status = status;

	switch (status) {
	case DLM_LKSTS_WAITING:
		if (lkb->lkb_exflags & DLM_LKF_HEADQUE)
			list_add(&lkb->lkb_statequeue, &r->res_waitqueue);
		else
			list_add_tail(&lkb->lkb_statequeue, &r->res_waitqueue);
		break;
	case DLM_LKSTS_GRANTED:
		/* convention says granted locks kept in order of grmode */
		lkb_add_ordered(&lkb->lkb_statequeue, &r->res_grantqueue,
				lkb->lkb_grmode);
		break;
	case DLM_LKSTS_CONVERT:
		if (lkb->lkb_exflags & DLM_LKF_HEADQUE)
			list_add(&lkb->lkb_statequeue, &r->res_convertqueue);
		else
			list_add_tail(&lkb->lkb_statequeue,
				      &r->res_convertqueue);
		break;
	default:
		DLM_ASSERT(0, dlm_print_lkb(lkb); printk("sts=%d\n", status););
	}
}

static void del_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	lkb->lkb_status = 0;
	list_del(&lkb->lkb_statequeue);
	unhold_lkb(lkb);
}

static void move_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int sts)
{
	hold_lkb(lkb);
	del_lkb(r, lkb);
	add_lkb(r, lkb, sts);
	unhold_lkb(lkb);
}

static int msg_reply_type(int mstype)
{
	switch (mstype) {
	case DLM_MSG_REQUEST:
		return DLM_MSG_REQUEST_REPLY;
	case DLM_MSG_CONVERT:
		return DLM_MSG_CONVERT_REPLY;
	case DLM_MSG_UNLOCK:
		return DLM_MSG_UNLOCK_REPLY;
	case DLM_MSG_CANCEL:
		return DLM_MSG_CANCEL_REPLY;
	case DLM_MSG_LOOKUP:
		return DLM_MSG_LOOKUP_REPLY;
	}
	return -1;
}

/* add/remove lkb from global waiters list of lkb's waiting for
   a reply from a remote node */

static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int error = 0;

	mutex_lock(&ls->ls_waiters_mutex);

	if (is_overlap_unlock(lkb) ||
	    (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL))) {
		error = -EINVAL;
		goto out;
	}

	if (lkb->lkb_wait_type || is_overlap_cancel(lkb)) {
		switch (mstype) {
		case DLM_MSG_UNLOCK:
			lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK;
			break;
		case DLM_MSG_CANCEL:
			lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL;
			break;
		default:
			error = -EBUSY;
			goto out;
		}
		lkb->lkb_wait_count++;
		hold_lkb(lkb);

		log_debug(ls, "add overlap %x cur %d new %d count %d flags %x",
			  lkb->lkb_id, lkb->lkb_wait_type, mstype,
			  lkb->lkb_wait_count, lkb->lkb_flags);
		goto out;
	}

	DLM_ASSERT(!lkb->lkb_wait_count,
		   dlm_print_lkb(lkb);
		   printk("wait_count %d\n", lkb->lkb_wait_count););

	lkb->lkb_wait_count++;
	lkb->lkb_wait_type = mstype;
	hold_lkb(lkb);
	list_add(&lkb->lkb_wait_reply, &ls->ls_waiters);
 out:
	if (error)
		log_error(ls, "add_to_waiters %x error %d flags %x %d %d %s",
			  lkb->lkb_id, error, lkb->lkb_flags, mstype,
			  lkb->lkb_wait_type, lkb->lkb_resource->res_name);
	mutex_unlock(&ls->ls_waiters_mutex);
	return error;
}

/* We clear the RESEND flag because we might be taking an lkb off the waiters
   list as part of process_requestqueue (e.g. a lookup that has an optimized
   request reply on the requestqueue) between dlm_recover_waiters_pre() which
   set RESEND and dlm_recover_waiters_post() */

static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int overlap_done = 0;

	if (is_overlap_unlock(lkb) && (mstype == DLM_MSG_UNLOCK_REPLY)) {
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
		overlap_done = 1;
		goto out_del;
	}

	if (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL_REPLY)) {
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
		overlap_done = 1;
		goto out_del;
	}

	/* N.B. type of reply may not always correspond to type of original
	   msg due to lookup->request optimization, verify others? */

	if (lkb->lkb_wait_type) {
		lkb->lkb_wait_type = 0;
		goto out_del;
	}

	log_error(ls, "remove_from_waiters lkid %x flags %x types %d %d",
		  lkb->lkb_id, lkb->lkb_flags, mstype, lkb->lkb_wait_type);
	return -1;

 out_del:
	/* the force-unlock/cancel has completed and we haven't recvd a reply
	   to the op that was in progress prior to the unlock/cancel; we
	   give up on any reply to the earlier op.  FIXME: not sure when/how
	   this would happen */

	if (overlap_done && lkb->lkb_wait_type) {
		log_error(ls, "remove_from_waiters %x reply %d give up on %d",
			  lkb->lkb_id, mstype, lkb->lkb_wait_type);
		lkb->lkb_wait_count--;
		lkb->lkb_wait_type = 0;
	}

	DLM_ASSERT(lkb->lkb_wait_count, dlm_print_lkb(lkb););

	lkb->lkb_flags &= ~DLM_IFL_RESEND;
	lkb->lkb_wait_count--;
	if (!lkb->lkb_wait_count)
		list_del_init(&lkb->lkb_wait_reply);
	unhold_lkb(lkb);
	return 0;
}

static int remove_from_waiters(struct dlm_lkb *lkb, int mstype)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int error;

	mutex_lock(&ls->ls_waiters_mutex);
	error = _remove_from_waiters(lkb, mstype);
	mutex_unlock(&ls->ls_waiters_mutex);
	return error;
}

/* Handles situations where we might be processing a "fake" or "stub" reply in
   which we can't try to take waiters_mutex again. */

static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int error;

	if (ms != &ls->ls_stub_ms)
		mutex_lock(&ls->ls_waiters_mutex);
	error = _remove_from_waiters(lkb, ms->m_type);
	if (ms != &ls->ls_stub_ms)
		mutex_unlock(&ls->ls_waiters_mutex);
	return error;
}

static void dir_remove(struct dlm_rsb *r)
{
	int to_nodeid;

	if (dlm_no_directory(r->res_ls))
		return;

	to_nodeid = dlm_dir_nodeid(r);
	if (to_nodeid != dlm_our_nodeid())
		send_remove(r);
	else
		dlm_dir_remove_entry(r->res_ls, to_nodeid,
				     r->res_name, r->res_length);
}

/* FIXME: shouldn't this be able to exit as soon as one non-due rsb is
   found since they are in order of newest to oldest? */

static int shrink_bucket(struct dlm_ls *ls, int b)
{
	struct dlm_rsb *r;
	int count = 0, found;

	for (;;) {
		found = 0;
		write_lock(&ls->ls_rsbtbl[b].lock);
		list_for_each_entry_reverse(r, &ls->ls_rsbtbl[b].toss,
					    res_hashchain) {
			if (!time_after_eq(jiffies, r->res_toss_time +
					   dlm_config.ci_toss_secs * HZ))
				continue;
			found = 1;
			break;
		}

		if (!found) {
			write_unlock(&ls->ls_rsbtbl[b].lock);
			break;
		}

		if (kref_put(&r->res_ref, kill_rsb)) {
			list_del(&r->res_hashchain);
			write_unlock(&ls->ls_rsbtbl[b].lock);

			if (is_master(r))
				dir_remove(r);
			free_rsb(r);
			count++;
		} else {
			write_unlock(&ls->ls_rsbtbl[b].lock);
			log_error(ls, "tossed rsb in use %s", r->res_name);
		}
	}

	return count;
}

void dlm_scan_rsbs(struct dlm_ls *ls)
{
	int i;

	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
		shrink_bucket(ls, i);
		if (dlm_locking_stopped(ls))
			break;
		cond_resched();
	}
}

static void add_timeout(struct dlm_lkb *lkb)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;

	if (is_master_copy(lkb)) {
		lkb->lkb_timestamp = jiffies;
		return;
	}

	if (test_bit(LSFL_TIMEWARN, &ls->ls_flags) &&
	    !(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) {
		lkb->lkb_flags |= DLM_IFL_WATCH_TIMEWARN;
		goto add_it;
	}
	if (lkb->lkb_exflags & DLM_LKF_TIMEOUT)
		goto add_it;
	return;

 add_it:
	DLM_ASSERT(list_empty(&lkb->lkb_time_list), dlm_print_lkb(lkb););
	mutex_lock(&ls->ls_timeout_mutex);
	hold_lkb(lkb);
	lkb->lkb_timestamp = jiffies;
	list_add_tail(&lkb->lkb_time_list, &ls->ls_timeout);
	mutex_unlock(&ls->ls_timeout_mutex);
}

static void del_timeout(struct dlm_lkb *lkb)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;

	mutex_lock(&ls->ls_timeout_mutex);
	if (!list_empty(&lkb->lkb_time_list)) {
		list_del_init(&lkb->lkb_time_list);
		unhold_lkb(lkb);
	}
	mutex_unlock(&ls->ls_timeout_mutex);
}

/* FIXME: is it safe to look at lkb_exflags, lkb_flags, lkb_timestamp, and
   lkb_lksb_timeout without lock_rsb?  Note: we can't lock timeout_mutex
   and then lock rsb because of lock ordering in add_timeout.  We may need
   to specify some special timeout-related bits in the lkb that are just to
   be accessed under the timeout_mutex. */

void dlm_scan_timeout(struct dlm_ls *ls)
{
	struct dlm_rsb *r;
	struct dlm_lkb *lkb;
	int do_cancel, do_warn;

	for (;;) {
		if (dlm_locking_stopped(ls))
			break;

		do_cancel = 0;
		do_warn = 0;
		mutex_lock(&ls->ls_timeout_mutex);
		list_for_each_entry(lkb, &ls->ls_timeout, lkb_time_list) {

			if ((lkb->lkb_exflags & DLM_LKF_TIMEOUT) &&
			    time_after_eq(jiffies, lkb->lkb_timestamp +
					  lkb->lkb_timeout_cs * HZ/100))
				do_cancel = 1;

			if ((lkb->lkb_flags & DLM_IFL_WATCH_TIMEWARN) &&
			    time_after_eq(jiffies, lkb->lkb_timestamp +
				   	   dlm_config.ci_timewarn_cs * HZ/100))
				do_warn = 1;

			if (!do_cancel && !do_warn)
				continue;
			hold_lkb(lkb);
			break;
		}
		mutex_unlock(&ls->ls_timeout_mutex);

		if (!do_cancel && !do_warn)
			break;

		r = lkb->lkb_resource;
		hold_rsb(r);
		lock_rsb(r);

		if (do_warn) {
			/* clear flag so we only warn once */
			lkb->lkb_flags &= ~DLM_IFL_WATCH_TIMEWARN;
			if (!(lkb->lkb_exflags & DLM_LKF_TIMEOUT))
				del_timeout(lkb);
			dlm_timeout_warn(lkb);
		}

		if (do_cancel) {
			log_debug(ls, "timeout cancel %x node %d %s",
				  lkb->lkb_id, lkb->lkb_nodeid, r->res_name);
			lkb->lkb_flags &= ~DLM_IFL_WATCH_TIMEWARN;
			lkb->lkb_flags |= DLM_IFL_TIMEOUT_CANCEL;
			del_timeout(lkb);
			_cancel_lock(r, lkb);
		}

		unlock_rsb(r);
		unhold_rsb(r);
		dlm_put_lkb(lkb);
	}
}

/* This is only called by dlm_recoverd, and we rely on dlm_ls_stop() stopping
   dlm_recoverd before checking/setting ls_recover_begin. */

void dlm_adjust_timeouts(struct dlm_ls *ls)
{
	struct dlm_lkb *lkb;
	long adj = jiffies - ls->ls_recover_begin;

	ls->ls_recover_begin = 0;
	mutex_lock(&ls->ls_timeout_mutex);
	list_for_each_entry(lkb, &ls->ls_timeout, lkb_time_list)
		lkb->lkb_timestamp += adj;
	mutex_unlock(&ls->ls_timeout_mutex);
}

/* lkb is master or local copy */

static void set_lvb_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int b, len = r->res_ls->ls_lvblen;

	/* b=1 lvb returned to caller
	   b=0 lvb written to rsb or invalidated
	   b=-1 do nothing */

	b =  dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1];

	if (b == 1) {
		if (!lkb->lkb_lvbptr)
			return;

		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
			return;

		if (!r->res_lvbptr)
			return;

		memcpy(lkb->lkb_lvbptr, r->res_lvbptr, len);
		lkb->lkb_lvbseq = r->res_lvbseq;

	} else if (b == 0) {
		if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) {
			rsb_set_flag(r, RSB_VALNOTVALID);
			return;
		}

		if (!lkb->lkb_lvbptr)
			return;

		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
			return;

		if (!r->res_lvbptr)
			r->res_lvbptr = allocate_lvb(r->res_ls);

		if (!r->res_lvbptr)
			return;

		memcpy(r->res_lvbptr, lkb->lkb_lvbptr, len);
		r->res_lvbseq++;
		lkb->lkb_lvbseq = r->res_lvbseq;
		rsb_clear_flag(r, RSB_VALNOTVALID);
	}

	if (rsb_flag(r, RSB_VALNOTVALID))
		lkb->lkb_sbflags |= DLM_SBF_VALNOTVALID;
}

static void set_lvb_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	if (lkb->lkb_grmode < DLM_LOCK_PW)
		return;

	if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) {
		rsb_set_flag(r, RSB_VALNOTVALID);
		return;
	}

	if (!lkb->lkb_lvbptr)
		return;

	if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
		return;

	if (!r->res_lvbptr)
		r->res_lvbptr = allocate_lvb(r->res_ls);

	if (!r->res_lvbptr)
		return;

	memcpy(r->res_lvbptr, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
	r->res_lvbseq++;
	rsb_clear_flag(r, RSB_VALNOTVALID);
}

/* lkb is process copy (pc) */

static void set_lvb_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb,
			    struct dlm_message *ms)
{
	int b;

	if (!lkb->lkb_lvbptr)
		return;

	if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
		return;

	b = dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1];
	if (b == 1) {
		int len = receive_extralen(ms);
		memcpy(lkb->lkb_lvbptr, ms->m_extra, len);
		lkb->lkb_lvbseq = ms->m_lvbseq;
	}
}

/* Manipulate lkb's on rsb's convert/granted/waiting queues
   remove_lock -- used for unlock, removes lkb from granted
   revert_lock -- used for cancel, moves lkb from convert to granted
   grant_lock  -- used for request and convert, adds lkb to granted or
                  moves lkb from convert or waiting to granted

   Each of these is used for master or local copy lkb's.  There is
   also a _pc() variation used to make the corresponding change on
   a process copy (pc) lkb. */

static void _remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	del_lkb(r, lkb);
	lkb->lkb_grmode = DLM_LOCK_IV;
	/* this unhold undoes the original ref from create_lkb()
	   so this leads to the lkb being freed */
	unhold_lkb(lkb);
}

static void remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	set_lvb_unlock(r, lkb);
	_remove_lock(r, lkb);
}

static void remove_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	_remove_lock(r, lkb);
}

/* returns: 0 did nothing
	    1 moved lock to granted
	   -1 removed lock */

static int revert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int rv = 0;

	lkb->lkb_rqmode = DLM_LOCK_IV;

	switch (lkb->lkb_status) {
	case DLM_LKSTS_GRANTED:
		break;
	case DLM_LKSTS_CONVERT:
		move_lkb(r, lkb, DLM_LKSTS_GRANTED);
		rv = 1;
		break;
	case DLM_LKSTS_WAITING:
		del_lkb(r, lkb);
		lkb->lkb_grmode = DLM_LOCK_IV;
		/* this unhold undoes the original ref from create_lkb()
		   so this leads to the lkb being freed */
		unhold_lkb(lkb);
		rv = -1;
		break;
	default:
		log_print("invalid status for revert %d", lkb->lkb_status);
	}
	return rv;
}

static int revert_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	return revert_lock(r, lkb);
}

static void _grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	if (lkb->lkb_grmode != lkb->lkb_rqmode) {
		lkb->lkb_grmode = lkb->lkb_rqmode;
		if (lkb->lkb_status)
			move_lkb(r, lkb, DLM_LKSTS_GRANTED);
		else
			add_lkb(r, lkb, DLM_LKSTS_GRANTED);
	}

	lkb->lkb_rqmode = DLM_LOCK_IV;
}

static void grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	set_lvb_lock(r, lkb);
	_grant_lock(r, lkb);
	lkb->lkb_highbast = 0;
}

static void grant_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb,
			  struct dlm_message *ms)
{
	set_lvb_lock_pc(r, lkb, ms);
	_grant_lock(r, lkb);
}

/* called by grant_pending_locks() which means an async grant message must
   be sent to the requesting node in addition to granting the lock if the
   lkb belongs to a remote node. */

static void grant_lock_pending(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	grant_lock(r, lkb);
	if (is_master_copy(lkb))
		send_grant(r, lkb);
	else
		queue_cast(r, lkb, 0);
}

/* The special CONVDEADLK, ALTPR and ALTCW flags allow the master to
   change the granted/requested modes.  We're munging things accordingly in
   the process copy.
   CONVDEADLK: our grmode may have been forced down to NL to resolve a
   conversion deadlock
   ALTPR/ALTCW: our rqmode may have been changed to PR or CW to become
   compatible with other granted locks */

static void munge_demoted(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	if (ms->m_type != DLM_MSG_CONVERT_REPLY) {
		log_print("munge_demoted %x invalid reply type %d",
			  lkb->lkb_id, ms->m_type);
		return;
	}

	if (lkb->lkb_rqmode == DLM_LOCK_IV || lkb->lkb_grmode == DLM_LOCK_IV) {
		log_print("munge_demoted %x invalid modes gr %d rq %d",
			  lkb->lkb_id, lkb->lkb_grmode, lkb->lkb_rqmode);
		return;
	}

	lkb->lkb_grmode = DLM_LOCK_NL;
}

static void munge_altmode(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	if (ms->m_type != DLM_MSG_REQUEST_REPLY &&
	    ms->m_type != DLM_MSG_GRANT) {
		log_print("munge_altmode %x invalid reply type %d",
			  lkb->lkb_id, ms->m_type);
		return;
	}

	if (lkb->lkb_exflags & DLM_LKF_ALTPR)
		lkb->lkb_rqmode = DLM_LOCK_PR;
	else if (lkb->lkb_exflags & DLM_LKF_ALTCW)
		lkb->lkb_rqmode = DLM_LOCK_CW;
	else {
		log_print("munge_altmode invalid exflags %x", lkb->lkb_exflags);
		dlm_print_lkb(lkb);
	}
}

static inline int first_in_list(struct dlm_lkb *lkb, struct list_head *head)
{
	struct dlm_lkb *first = list_entry(head->next, struct dlm_lkb,
					   lkb_statequeue);
	if (lkb->lkb_id == first->lkb_id)
		return 1;

	return 0;
}

/* Check if the given lkb conflicts with another lkb on the queue. */

static int queue_conflict(struct list_head *head, struct dlm_lkb *lkb)
{
	struct dlm_lkb *this;

	list_for_each_entry(this, head, lkb_statequeue) {
		if (this == lkb)
			continue;
		if (!modes_compat(this, lkb))
			return 1;
	}
	return 0;
}

/*
 * "A conversion deadlock arises with a pair of lock requests in the converting
 * queue for one resource.  The granted mode of each lock blocks the requested
 * mode of the other lock."
 *
 * Part 2: if the granted mode of lkb is preventing an earlier lkb in the
 * convert queue from being granted, then deadlk/demote lkb.
 *
 * Example:
 * Granted Queue: empty
 * Convert Queue: NL->EX (first lock)
 *                PR->EX (second lock)
 *
 * The first lock can't be granted because of the granted mode of the second
 * lock and the second lock can't be granted because it's not first in the
 * list.  We either cancel lkb's conversion (PR->EX) and return EDEADLK, or we
 * demote the granted mode of lkb (from PR to NL) if it has the CONVDEADLK
 * flag set and return DEMOTED in the lksb flags.
 *
 * Originally, this function detected conv-deadlk in a more limited scope:
 * - if !modes_compat(lkb1, lkb2) && !modes_compat(lkb2, lkb1), or
 * - if lkb1 was the first entry in the queue (not just earlier), and was
 *   blocked by the granted mode of lkb2, and there was nothing on the
 *   granted queue preventing lkb1 from being granted immediately, i.e.
 *   lkb2 was the only thing preventing lkb1 from being granted.
 *
 * That second condition meant we'd only say there was conv-deadlk if
 * resolving it (by demotion) would lead to the first lock on the convert
 * queue being granted right away.  It allowed conversion deadlocks to exist
 * between locks on the convert queue while they couldn't be granted anyway.
 *
 * Now, we detect and take action on conversion deadlocks immediately when
 * they're created, even if they may not be immediately consequential.  If
 * lkb1 exists anywhere in the convert queue and lkb2 comes in with a granted
 * mode that would prevent lkb1's conversion from being granted, we do a
 * deadlk/demote on lkb2 right away and don't let it onto the convert queue.
 * I think this means that the lkb_is_ahead condition below should always
 * be zero, i.e. there will never be conv-deadlk between two locks that are
 * both already on the convert queue.
 */

static int conversion_deadlock_detect(struct dlm_rsb *r, struct dlm_lkb *lkb2)
{
	struct dlm_lkb *lkb1;
	int lkb_is_ahead = 0;

	list_for_each_entry(lkb1, &r->res_convertqueue, lkb_statequeue) {
		if (lkb1 == lkb2) {
			lkb_is_ahead = 1;
			continue;
		}

		if (!lkb_is_ahead) {
			if (!modes_compat(lkb2, lkb1))
				return 1;
		} else {
			if (!modes_compat(lkb2, lkb1) &&
			    !modes_compat(lkb1, lkb2))
				return 1;
		}
	}
	return 0;
}

/*
 * Return 1 if the lock can be granted, 0 otherwise.
 * Also detect and resolve conversion deadlocks.
 *
 * lkb is the lock to be granted
 *
 * now is 1 if the function is being called in the context of the
 * immediate request, it is 0 if called later, after the lock has been
 * queued.
 *
 * References are from chapter 6 of "VAXcluster Principles" by Roy Davis
 */

static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
{
	int8_t conv = (lkb->lkb_grmode != DLM_LOCK_IV);

	/*
	 * 6-10: Version 5.4 introduced an option to address the phenomenon of
	 * a new request for a NL mode lock being blocked.
	 *
	 * 6-11: If the optional EXPEDITE flag is used with the new NL mode
	 * request, then it would be granted.  In essence, the use of this flag
	 * tells the Lock Manager to expedite theis request by not considering
	 * what may be in the CONVERTING or WAITING queues...  As of this
	 * writing, the EXPEDITE flag can be used only with new requests for NL
	 * mode locks.  This flag is not valid for conversion requests.
	 *
	 * A shortcut.  Earlier checks return an error if EXPEDITE is used in a
	 * conversion or used with a non-NL requested mode.  We also know an
	 * EXPEDITE request is always granted immediately, so now must always
	 * be 1.  The full condition to grant an expedite request: (now &&
	 * !conv && lkb->rqmode == DLM_LOCK_NL && (flags & EXPEDITE)) can
	 * therefore be shortened to just checking the flag.
	 */

	if (lkb->lkb_exflags & DLM_LKF_EXPEDITE)
		return 1;

	/*
	 * A shortcut. Without this, !queue_conflict(grantqueue, lkb) would be
	 * added to the remaining conditions.
	 */

	if (queue_conflict(&r->res_grantqueue, lkb))
		goto out;

	/*
	 * 6-3: By default, a conversion request is immediately granted if the
	 * requested mode is compatible with the modes of all other granted
	 * locks
	 */

	if (queue_conflict(&r->res_convertqueue, lkb))
		goto out;

	/*
	 * 6-5: But the default algorithm for deciding whether to grant or
	 * queue conversion requests does not by itself guarantee that such
	 * requests are serviced on a "first come first serve" basis.  This, in
	 * turn, can lead to a phenomenon known as "indefinate postponement".
	 *
	 * 6-7: This issue is dealt with by using the optional QUECVT flag with
	 * the system service employed to request a lock conversion.  This flag
	 * forces certain conversion requests to be queued, even if they are
	 * compatible with the granted modes of other locks on the same
	 * resource.  Thus, the use of this flag results in conversion requests
	 * being ordered on a "first come first servce" basis.
	 *
	 * DCT: This condition is all about new conversions being able to occur
	 * "in place" while the lock remains on the granted queue (assuming
	 * nothing else conflicts.)  IOW if QUECVT isn't set, a conversion
	 * doesn't _have_ to go onto the convert queue where it's processed in
	 * order.  The "now" variable is necessary to distinguish converts
	 * being received and processed for the first time now, because once a
	 * convert is moved to the conversion queue the condition below applies
	 * requiring fifo granting.
	 */

	if (now && conv && !(lkb->lkb_exflags & DLM_LKF_QUECVT))
		return 1;

	/*
	 * The NOORDER flag is set to avoid the standard vms rules on grant
	 * order.
	 */

	if (lkb->lkb_exflags & DLM_LKF_NOORDER)
		return 1;

	/*
	 * 6-3: Once in that queue [CONVERTING], a conversion request cannot be
	 * granted until all other conversion requests ahead of it are granted
	 * and/or canceled.
	 */

	if (!now && conv && first_in_list(lkb, &r->res_convertqueue))
		return 1;

	/*
	 * 6-4: By default, a new request is immediately granted only if all
	 * three of the following conditions are satisfied when the request is
	 * issued:
	 * - The queue of ungranted conversion requests for the resource is
	 *   empty.
	 * - The queue of ungranted new requests for the resource is empty.
	 * - The mode of the new request is compatible with the most
	 *   restrictive mode of all granted locks on the resource.
	 */

	if (now && !conv && list_empty(&r->res_convertqueue) &&
	    list_empty(&r->res_waitqueue))
		return 1;

	/*
	 * 6-4: Once a lock request is in the queue of ungranted new requests,
	 * it cannot be granted until the queue of ungranted conversion
	 * requests is empty, all ungranted new requests ahead of it are
	 * granted and/or canceled, and it is compatible with the granted mode
	 * of the most restrictive lock granted on the resource.
	 */

	if (!now && !conv && list_empty(&r->res_convertqueue) &&
	    first_in_list(lkb, &r->res_waitqueue))
		return 1;
 out:
	return 0;
}

static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
			  int *err)
{
	int rv;
	int8_t alt = 0, rqmode = lkb->lkb_rqmode;
	int8_t is_convert = (lkb->lkb_grmode != DLM_LOCK_IV);

	if (err)
		*err = 0;

	rv = _can_be_granted(r, lkb, now);
	if (rv)
		goto out;

	/*
	 * The CONVDEADLK flag is non-standard and tells the dlm to resolve
	 * conversion deadlocks by demoting grmode to NL, otherwise the dlm
	 * cancels one of the locks.
	 */

	if (is_convert && can_be_queued(lkb) &&
	    conversion_deadlock_detect(r, lkb)) {
		if (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) {
			lkb->lkb_grmode = DLM_LOCK_NL;
			lkb->lkb_sbflags |= DLM_SBF_DEMOTED;
		} else if (!(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) {
			if (err)
				*err = -EDEADLK;
			else {
				log_print("can_be_granted deadlock %x now %d",
					  lkb->lkb_id, now);
				dlm_dump_rsb(r);
			}
		}
		goto out;
	}

	/*
	 * The ALTPR and ALTCW flags are non-standard and tell the dlm to try
	 * to grant a request in a mode other than the normal rqmode.  It's a
	 * simple way to provide a big optimization to applications that can
	 * use them.
	 */

	if (rqmode != DLM_LOCK_PR && (lkb->lkb_exflags & DLM_LKF_ALTPR))
		alt = DLM_LOCK_PR;
	else if (rqmode != DLM_LOCK_CW && (lkb->lkb_exflags & DLM_LKF_ALTCW))
		alt = DLM_LOCK_CW;

	if (alt) {
		lkb->lkb_rqmode = alt;
		rv = _can_be_granted(r, lkb, now);
		if (rv)
			lkb->lkb_sbflags |= DLM_SBF_ALTMODE;
		else
			lkb->lkb_rqmode = rqmode;
	}
 out:
	return rv;
}

/* FIXME: I don't think that can_be_granted() can/will demote or find deadlock
   for locks pending on the convert list.  Once verified (watch for these
   log_prints), we should be able to just call _can_be_granted() and not
   bother with the demote/deadlk cases here (and there's no easy way to deal
   with a deadlk here, we'd have to generate something like grant_lock with
   the deadlk error.) */

/* Returns the highest requested mode of all blocked conversions; sets
   cw if there's a blocked conversion to DLM_LOCK_CW. */

static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw)
{
	struct dlm_lkb *lkb, *s;
	int hi, demoted, quit, grant_restart, demote_restart;
	int deadlk;

	quit = 0;
 restart:
	grant_restart = 0;
	demote_restart = 0;
	hi = DLM_LOCK_IV;

	list_for_each_entry_safe(lkb, s, &r->res_convertqueue, lkb_statequeue) {
		demoted = is_demoted(lkb);
		deadlk = 0;

		if (can_be_granted(r, lkb, 0, &deadlk)) {
			grant_lock_pending(r, lkb);
			grant_restart = 1;
			continue;
		}

		if (!demoted && is_demoted(lkb)) {
			log_print("WARN: pending demoted %x node %d %s",
				  lkb->lkb_id, lkb->lkb_nodeid, r->res_name);
			demote_restart = 1;
			continue;
		}

		if (deadlk) {
			log_print("WARN: pending deadlock %x node %d %s",
				  lkb->lkb_id, lkb->lkb_nodeid, r->res_name);
			dlm_dump_rsb(r);
			continue;
		}

		hi = max_t(int, lkb->lkb_rqmode, hi);

		if (cw && lkb->lkb_rqmode == DLM_LOCK_CW)
			*cw = 1;
	}

	if (grant_restart)
		goto restart;
	if (demote_restart && !quit) {
		quit = 1;
		goto restart;
	}

	return max_t(int, high, hi);
}

static int grant_pending_wait(struct dlm_rsb *r, int high, int *cw)
{
	struct dlm_lkb *lkb, *s;

	list_for_each_entry_safe(lkb, s, &r->res_waitqueue, lkb_statequeue) {
		if (can_be_granted(r, lkb, 0, NULL))
			grant_lock_pending(r, lkb);
                else {
			high = max_t(int, lkb->lkb_rqmode, high);
			if (lkb->lkb_rqmode == DLM_LOCK_CW)
				*cw = 1;
		}
	}

	return high;
}

/* cw of 1 means there's a lock with a rqmode of DLM_LOCK_CW that's blocked
   on either the convert or waiting queue.
   high is the largest rqmode of all locks blocked on the convert or
   waiting queue. */

static int lock_requires_bast(struct dlm_lkb *gr, int high, int cw)
{
	if (gr->lkb_grmode == DLM_LOCK_PR && cw) {
		if (gr->lkb_highbast < DLM_LOCK_EX)
			return 1;
		return 0;
	}

	if (gr->lkb_highbast < high &&
	    !__dlm_compat_matrix[gr->lkb_grmode+1][high+1])
		return 1;
	return 0;
}

static void grant_pending_locks(struct dlm_rsb *r)
{
	struct dlm_lkb *lkb, *s;
	int high = DLM_LOCK_IV;
	int cw = 0;

	DLM_ASSERT(is_master(r), dlm_dump_rsb(r););

	high = grant_pending_convert(r, high, &cw);
	high = grant_pending_wait(r, high, &cw);

	if (high == DLM_LOCK_IV)
		return;

	/*
	 * If there are locks left on the wait/convert queue then send blocking
	 * ASTs to granted locks based on the largest requested mode (high)
	 * found above.
	 */

	list_for_each_entry_safe(lkb, s, &r->res_grantqueue, lkb_statequeue) {
		if (lkb->lkb_bastaddr && lock_requires_bast(lkb, high, cw)) {
			if (cw && high == DLM_LOCK_PR)
				queue_bast(r, lkb, DLM_LOCK_CW);
			else
				queue_bast(r, lkb, high);
			lkb->lkb_highbast = high;
		}
	}
}

static int modes_require_bast(struct dlm_lkb *gr, struct dlm_lkb *rq)
{
	if ((gr->lkb_grmode == DLM_LOCK_PR && rq->lkb_rqmode == DLM_LOCK_CW) ||
	    (gr->lkb_grmode == DLM_LOCK_CW && rq->lkb_rqmode == DLM_LOCK_PR)) {
		if (gr->lkb_highbast < DLM_LOCK_EX)
			return 1;
		return 0;
	}

	if (gr->lkb_highbast < rq->lkb_rqmode && !modes_compat(gr, rq))
		return 1;
	return 0;
}

static void send_bast_queue(struct dlm_rsb *r, struct list_head *head,
			    struct dlm_lkb *lkb)
{
	struct dlm_lkb *gr;

	list_for_each_entry(gr, head, lkb_statequeue) {
		if (gr->lkb_bastaddr && modes_require_bast(gr, lkb)) {
			queue_bast(r, gr, lkb->lkb_rqmode);
			gr->lkb_highbast = lkb->lkb_rqmode;
		}
	}
}

static void send_blocking_asts(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	send_bast_queue(r, &r->res_grantqueue, lkb);
}

static void send_blocking_asts_all(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	send_bast_queue(r, &r->res_grantqueue, lkb);
	send_bast_queue(r, &r->res_convertqueue, lkb);
}

/* set_master(r, lkb) -- set the master nodeid of a resource

   The purpose of this function is to set the nodeid field in the given
   lkb using the nodeid field in the given rsb.  If the rsb's nodeid is
   known, it can just be copied to the lkb and the function will return
   0.  If the rsb's nodeid is _not_ known, it needs to be looked up
   before it can be copied to the lkb.

   When the rsb nodeid is being looked up remotely, the initial lkb
   causing the lookup is kept on the ls_waiters list waiting for the
   lookup reply.  Other lkb's waiting for the same rsb lookup are kept
   on the rsb's res_lookup list until the master is verified.

   Return values:
   0: nodeid is set in rsb/lkb and the caller should go ahead and use it
   1: the rsb master is not available and the lkb has been placed on
      a wait queue
*/

static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	struct dlm_ls *ls = r->res_ls;
	int error, dir_nodeid, ret_nodeid, our_nodeid = dlm_our_nodeid();

	if (rsb_flag(r, RSB_MASTER_UNCERTAIN)) {
		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
		r->res_first_lkid = lkb->lkb_id;
		lkb->lkb_nodeid = r->res_nodeid;
		return 0;
	}

	if (r->res_first_lkid && r->res_first_lkid != lkb->lkb_id) {
		list_add_tail(&lkb->lkb_rsb_lookup, &r->res_lookup);
		return 1;
	}

	if (r->res_nodeid == 0) {
		lkb->lkb_nodeid = 0;
		return 0;
	}

	if (r->res_nodeid > 0) {
		lkb->lkb_nodeid = r->res_nodeid;
		return 0;
	}

	DLM_ASSERT(r->res_nodeid == -1, dlm_dump_rsb(r););

	dir_nodeid = dlm_dir_nodeid(r);

	if (dir_nodeid != our_nodeid) {
		r->res_first_lkid = lkb->lkb_id;
		send_lookup(r, lkb);
		return 1;
	}

	for (;;) {
		/* It's possible for dlm_scand to remove an old rsb for
		   this same resource from the toss list, us to create
		   a new one, look up the master locally, and find it
		   already exists just before dlm_scand does the
		   dir_remove() on the previous rsb. */

		error = dlm_dir_lookup(ls, our_nodeid, r->res_name,
				       r->res_length, &ret_nodeid);
		if (!error)
			break;
		log_debug(ls, "dir_lookup error %d %s", error, r->res_name);
		schedule();
	}

	if (ret_nodeid == our_nodeid) {
		r->res_first_lkid = 0;
		r->res_nodeid = 0;
		lkb->lkb_nodeid = 0;
	} else {
		r->res_first_lkid = lkb->lkb_id;
		r->res_nodeid = ret_nodeid;
		lkb->lkb_nodeid = ret_nodeid;
	}
	return 0;
}

static void process_lookup_list(struct dlm_rsb *r)
{
	struct dlm_lkb *lkb, *safe;

	list_for_each_entry_safe(lkb, safe, &r->res_lookup, lkb_rsb_lookup) {
		list_del_init(&lkb->lkb_rsb_lookup);
		_request_lock(r, lkb);
		schedule();
	}
}

/* confirm_master -- confirm (or deny) an rsb's master nodeid */

static void confirm_master(struct dlm_rsb *r, int error)
{
	struct dlm_lkb *lkb;

	if (!r->res_first_lkid)
		return;

	switch (error) {
	case 0:
	case -EINPROGRESS:
		r->res_first_lkid = 0;
		process_lookup_list(r);
		break;

	case -EAGAIN:
		/* the remote master didn't queue our NOQUEUE request;
		   make a waiting lkb the first_lkid */

		r->res_first_lkid = 0;

		if (!list_empty(&r->res_lookup)) {
			lkb = list_entry(r->res_lookup.next, struct dlm_lkb,
					 lkb_rsb_lookup);
			list_del_init(&lkb->lkb_rsb_lookup);
			r->res_first_lkid = lkb->lkb_id;
			_request_lock(r, lkb);
		} else
			r->res_nodeid = -1;
		break;

	default:
		log_error(r->res_ls, "confirm_master unknown error %d", error);
	}
}

static int set_lock_args(int mode, struct dlm_lksb *lksb, uint32_t flags,
			 int namelen, unsigned long timeout_cs, void *ast,
			 void *astarg, void *bast, struct dlm_args *args)
{
	int rv = -EINVAL;

	/* check for invalid arg usage */

	if (mode < 0 || mode > DLM_LOCK_EX)
		goto out;

	if (!(flags & DLM_LKF_CONVERT) && (namelen > DLM_RESNAME_MAXLEN))
		goto out;

	if (flags & DLM_LKF_CANCEL)
		goto out;

	if (flags & DLM_LKF_QUECVT && !(flags & DLM_LKF_CONVERT))
		goto out;

	if (flags & DLM_LKF_CONVDEADLK && !(flags & DLM_LKF_CONVERT))
		goto out;

	if (flags & DLM_LKF_CONVDEADLK && flags & DLM_LKF_NOQUEUE)
		goto out;

	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_CONVERT)
		goto out;

	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_QUECVT)
		goto out;

	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_NOQUEUE)
		goto out;

	if (flags & DLM_LKF_EXPEDITE && mode != DLM_LOCK_NL)
		goto out;

	if (!ast || !lksb)
		goto out;

	if (flags & DLM_LKF_VALBLK && !lksb->sb_lvbptr)
		goto out;

	if (flags & DLM_LKF_CONVERT && !lksb->sb_lkid)
		goto out;

	/* these args will be copied to the lkb in validate_lock_args,
	   it cannot be done now because when converting locks, fields in
	   an active lkb cannot be modified before locking the rsb */

	args->flags = flags;
	args->astaddr = ast;
	args->astparam = (long) astarg;
	args->bastaddr = bast;
	args->timeout = timeout_cs;
	args->mode = mode;
	args->lksb = lksb;
	rv = 0;
 out:
	return rv;
}

static int set_unlock_args(uint32_t flags, void *astarg, struct dlm_args *args)
{
	if (flags & ~(DLM_LKF_CANCEL | DLM_LKF_VALBLK | DLM_LKF_IVVALBLK |
 		      DLM_LKF_FORCEUNLOCK))
		return -EINVAL;

	if (flags & DLM_LKF_CANCEL && flags & DLM_LKF_FORCEUNLOCK)
		return -EINVAL;

	args->flags = flags;
	args->astparam = (long) astarg;
	return 0;
}

static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
			      struct dlm_args *args)
{
	int rv = -EINVAL;

	if (args->flags & DLM_LKF_CONVERT) {
		if (lkb->lkb_flags & DLM_IFL_MSTCPY)
			goto out;

		if (args->flags & DLM_LKF_QUECVT &&
		    !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1])
			goto out;

		rv = -EBUSY;
		if (lkb->lkb_status != DLM_LKSTS_GRANTED)
			goto out;

		if (lkb->lkb_wait_type)
			goto out;

		if (is_overlap(lkb))
			goto out;
	}

	lkb->lkb_exflags = args->flags;
	lkb->lkb_sbflags = 0;
	lkb->lkb_astaddr = args->astaddr;
	lkb->lkb_astparam = args->astparam;
	lkb->lkb_bastaddr = args->bastaddr;
	lkb->lkb_rqmode = args->mode;
	lkb->lkb_lksb = args->lksb;
	lkb->lkb_lvbptr = args->lksb->sb_lvbptr;
	lkb->lkb_ownpid = (int) current->pid;
	lkb->lkb_timeout_cs = args->timeout;
	rv = 0;
 out:
	return rv;
}

/* when dlm_unlock() sees -EBUSY with CANCEL/FORCEUNLOCK it returns 0
   for success */

/* note: it's valid for lkb_nodeid/res_nodeid to be -1 when we get here
   because there may be a lookup in progress and it's valid to do
   cancel/unlockf on it */

static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int rv = -EINVAL;

	if (lkb->lkb_flags & DLM_IFL_MSTCPY) {
		log_error(ls, "unlock on MSTCPY %x", lkb->lkb_id);
		dlm_print_lkb(lkb);
		goto out;
	}

	/* an lkb may still exist even though the lock is EOL'ed due to a
	   cancel, unlock or failed noqueue request; an app can't use these
	   locks; return same error as if the lkid had not been found at all */

	if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
		log_debug(ls, "unlock on ENDOFLIFE %x", lkb->lkb_id);
		rv = -ENOENT;
		goto out;
	}

	/* an lkb may be waiting for an rsb lookup to complete where the
	   lookup was initiated by another lock */

	if (args->flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)) {
		if (!list_empty(&lkb->lkb_rsb_lookup)) {
			log_debug(ls, "unlock on rsb_lookup %x", lkb->lkb_id);
			list_del_init(&lkb->lkb_rsb_lookup);
			queue_cast(lkb->lkb_resource, lkb,
				   args->flags & DLM_LKF_CANCEL ?
				   -DLM_ECANCEL : -DLM_EUNLOCK);
			unhold_lkb(lkb); /* undoes create_lkb() */
			rv = -EBUSY;
			goto out;
		}
	}

	/* cancel not allowed with another cancel/unlock in progress */

	if (args->flags & DLM_LKF_CANCEL) {
		if (lkb->lkb_exflags & DLM_LKF_CANCEL)
			goto out;

		if (is_overlap(lkb))
			goto out;

		/* don't let scand try to do a cancel */
		del_timeout(lkb);

		if (lkb->lkb_flags & DLM_IFL_RESEND) {
			lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL;
			rv = -EBUSY;
			goto out;
		}

		switch (lkb->lkb_wait_type) {
		case DLM_MSG_LOOKUP:
		case DLM_MSG_REQUEST:
			lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL;
			rv = -EBUSY;
			goto out;
		case DLM_MSG_UNLOCK:
		case DLM_MSG_CANCEL:
			goto out;
		}
		/* add_to_waiters() will set OVERLAP_CANCEL */
		goto out_ok;
	}

	/* do we need to allow a force-unlock if there's a normal unlock
	   already in progress?  in what conditions could the normal unlock
	   fail such that we'd want to send a force-unlock to be sure? */

	if (args->flags & DLM_LKF_FORCEUNLOCK) {
		if (lkb->lkb_exflags & DLM_LKF_FORCEUNLOCK)
			goto out;

		if (is_overlap_unlock(lkb))
			goto out;

		/* don't let scand try to do a cancel */
		del_timeout(lkb);

		if (lkb->lkb_flags & DLM_IFL_RESEND) {
			lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK;
			rv = -EBUSY;
			goto out;
		}

		switch (lkb->lkb_wait_type) {
		case DLM_MSG_LOOKUP:
		case DLM_MSG_REQUEST:
			lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK;
			rv = -EBUSY;
			goto out;
		case DLM_MSG_UNLOCK:
			goto out;
		}
		/* add_to_waiters() will set OVERLAP_UNLOCK */
		goto out_ok;
	}

	/* normal unlock not allowed if there's any op in progress */
	rv = -EBUSY;
	if (lkb->lkb_wait_type || lkb->lkb_wait_count)
		goto out;

 out_ok:
	/* an overlapping op shouldn't blow away exflags from other op */
	lkb->lkb_exflags |= args->flags;
	lkb->lkb_sbflags = 0;
	lkb->lkb_astparam = args->astparam;
	rv = 0;
 out:
	if (rv)
		log_debug(ls, "validate_unlock_args %d %x %x %x %x %d %s", rv,
			  lkb->lkb_id, lkb->lkb_flags, lkb->lkb_exflags,
			  args->flags, lkb->lkb_wait_type,
			  lkb->lkb_resource->res_name);
	return rv;
}

/*
 * Four stage 4 varieties:
 * do_request(), do_convert(), do_unlock(), do_cancel()
 * These are called on the master node for the given lock and
 * from the central locking logic.
 */

static int do_request(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error = 0;

	if (can_be_granted(r, lkb, 1, NULL)) {
		grant_lock(r, lkb);
		queue_cast(r, lkb, 0);
		goto out;
	}

	if (can_be_queued(lkb)) {
		error = -EINPROGRESS;
		add_lkb(r, lkb, DLM_LKSTS_WAITING);
		send_blocking_asts(r, lkb);
		add_timeout(lkb);
		goto out;
	}

	error = -EAGAIN;
	if (force_blocking_asts(lkb))
		send_blocking_asts_all(r, lkb);
	queue_cast(r, lkb, -EAGAIN);

 out:
	return error;
}

static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error = 0;
	int deadlk = 0;

	/* changing an existing lock may allow others to be granted */

	if (can_be_granted(r, lkb, 1, &deadlk)) {
		grant_lock(r, lkb);
		queue_cast(r, lkb, 0);
		grant_pending_locks(r);
		goto out;
	}

	/* can_be_granted() detected that this lock would block in a conversion
	   deadlock, so we leave it on the granted queue and return EDEADLK in
	   the ast for the convert. */

	if (deadlk) {
		/* it's left on the granted queue */
		log_debug(r->res_ls, "deadlock %x node %d sts%d g%d r%d %s",
			  lkb->lkb_id, lkb->lkb_nodeid, lkb->lkb_status,
			  lkb->lkb_grmode, lkb->lkb_rqmode, r->res_name);
		revert_lock(r, lkb);
		queue_cast(r, lkb, -EDEADLK);
		error = -EDEADLK;
		goto out;
	}

	/* is_demoted() means the can_be_granted() above set the grmode
	   to NL, and left us on the granted queue.  This auto-demotion
	   (due to CONVDEADLK) might mean other locks, and/or this lock, are
	   now grantable.  We have to try to grant other converting locks
	   before we try again to grant this one. */

	if (is_demoted(lkb)) {
		grant_pending_convert(r, DLM_LOCK_IV, NULL);
		if (_can_be_granted(r, lkb, 1)) {
			grant_lock(r, lkb);
			queue_cast(r, lkb, 0);
			grant_pending_locks(r);
			goto out;
		}
		/* else fall through and move to convert queue */
	}

	if (can_be_queued(lkb)) {
		error = -EINPROGRESS;
		del_lkb(r, lkb);
		add_lkb(r, lkb, DLM_LKSTS_CONVERT);
		send_blocking_asts(r, lkb);
		add_timeout(lkb);
		goto out;
	}

	error = -EAGAIN;
	if (force_blocking_asts(lkb))
		send_blocking_asts_all(r, lkb);
	queue_cast(r, lkb, -EAGAIN);

 out:
	return error;
}

static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	remove_lock(r, lkb);
	queue_cast(r, lkb, -DLM_EUNLOCK);
	grant_pending_locks(r);
	return -DLM_EUNLOCK;
}

/* returns: 0 did nothing, -DLM_ECANCEL canceled lock */
 
static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	error = revert_lock(r, lkb);
	if (error) {
		queue_cast(r, lkb, -DLM_ECANCEL);
		grant_pending_locks(r);
		return -DLM_ECANCEL;
	}
	return 0;
}

/*
 * Four stage 3 varieties:
 * _request_lock(), _convert_lock(), _unlock_lock(), _cancel_lock()
 */

/* add a new lkb to a possibly new rsb, called by requesting process */

static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	/* set_master: sets lkb nodeid from r */

	error = set_master(r, lkb);
	if (error < 0)
		goto out;
	if (error) {
		error = 0;
		goto out;
	}

	if (is_remote(r))
		/* receive_request() calls do_request() on remote node */
		error = send_request(r, lkb);
	else
		error = do_request(r, lkb);
 out:
	return error;
}

/* change some property of an existing lkb, e.g. mode */

static int _convert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	if (is_remote(r))
		/* receive_convert() calls do_convert() on remote node */
		error = send_convert(r, lkb);
	else
		error = do_convert(r, lkb);

	return error;
}

/* remove an existing lkb from the granted queue */

static int _unlock_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	if (is_remote(r))
		/* receive_unlock() calls do_unlock() on remote node */
		error = send_unlock(r, lkb);
	else
		error = do_unlock(r, lkb);

	return error;
}

/* remove an existing lkb from the convert or wait queue */

static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	if (is_remote(r))
		/* receive_cancel() calls do_cancel() on remote node */
		error = send_cancel(r, lkb);
	else
		error = do_cancel(r, lkb);

	return error;
}

/*
 * Four stage 2 varieties:
 * request_lock(), convert_lock(), unlock_lock(), cancel_lock()
 */

static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, char *name,
			int len, struct dlm_args *args)
{
	struct dlm_rsb *r;
	int error;

	error = validate_lock_args(ls, lkb, args);
	if (error)
		goto out;

	error = find_rsb(ls, name, len, R_CREATE, &r);
	if (error)
		goto out;

	lock_rsb(r);

	attach_lkb(r, lkb);
	lkb->lkb_lksb->sb_lkid = lkb->lkb_id;

	error = _request_lock(r, lkb);

	unlock_rsb(r);
	put_rsb(r);

 out:
	return error;
}

static int convert_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
			struct dlm_args *args)
{
	struct dlm_rsb *r;
	int error;

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	error = validate_lock_args(ls, lkb, args);
	if (error)
		goto out;

	error = _convert_lock(r, lkb);
 out:
	unlock_rsb(r);
	put_rsb(r);
	return error;
}

static int unlock_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
		       struct dlm_args *args)
{
	struct dlm_rsb *r;
	int error;

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	error = validate_unlock_args(lkb, args);
	if (error)
		goto out;

	error = _unlock_lock(r, lkb);
 out:
	unlock_rsb(r);
	put_rsb(r);
	return error;
}

static int cancel_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
		       struct dlm_args *args)
{
	struct dlm_rsb *r;
	int error;

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	error = validate_unlock_args(lkb, args);
	if (error)
		goto out;

	error = _cancel_lock(r, lkb);
 out:
	unlock_rsb(r);
	put_rsb(r);
	return error;
}

/*
 * Two stage 1 varieties:  dlm_lock() and dlm_unlock()
 */

int dlm_lock(dlm_lockspace_t *lockspace,
	     int mode,
	     struct dlm_lksb *lksb,
	     uint32_t flags,
	     void *name,
	     unsigned int namelen,
	     uint32_t parent_lkid,
	     void (*ast) (void *astarg),
	     void *astarg,
	     void (*bast) (void *astarg, int mode))
{
	struct dlm_ls *ls;
	struct dlm_lkb *lkb;
	struct dlm_args args;
	int error, convert = flags & DLM_LKF_CONVERT;

	ls = dlm_find_lockspace_local(lockspace);
	if (!ls)
		return -EINVAL;

	dlm_lock_recovery(ls);

	if (convert)
		error = find_lkb(ls, lksb->sb_lkid, &lkb);
	else
		error = create_lkb(ls, &lkb);

	if (error)
		goto out;

	error = set_lock_args(mode, lksb, flags, namelen, 0, ast,
			      astarg, bast, &args);
	if (error)
		goto out_put;

	if (convert)
		error = convert_lock(ls, lkb, &args);
	else
		error = request_lock(ls, lkb, name, namelen, &args);

	if (error == -EINPROGRESS)
		error = 0;
 out_put:
	if (convert || error)
		__put_lkb(ls, lkb);
	if (error == -EAGAIN || error == -EDEADLK)
		error = 0;
 out:
	dlm_unlock_recovery(ls);
	dlm_put_lockspace(ls);
	return error;
}

int dlm_unlock(dlm_lockspace_t *lockspace,
	       uint32_t lkid,
	       uint32_t flags,
	       struct dlm_lksb *lksb,
	       void *astarg)
{
	struct dlm_ls *ls;
	struct dlm_lkb *lkb;
	struct dlm_args args;
	int error;

	ls = dlm_find_lockspace_local(lockspace);
	if (!ls)
		return -EINVAL;

	dlm_lock_recovery(ls);

	error = find_lkb(ls, lkid, &lkb);
	if (error)
		goto out;

	error = set_unlock_args(flags, astarg, &args);
	if (error)
		goto out_put;

	if (flags & DLM_LKF_CANCEL)
		error = cancel_lock(ls, lkb, &args);
	else
		error = unlock_lock(ls, lkb, &args);

	if (error == -DLM_EUNLOCK || error == -DLM_ECANCEL)
		error = 0;
	if (error == -EBUSY && (flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)))
		error = 0;
 out_put:
	dlm_put_lkb(lkb);
 out:
	dlm_unlock_recovery(ls);
	dlm_put_lockspace(ls);
	return error;
}

/*
 * send/receive routines for remote operations and replies
 *
 * send_args
 * send_common
 * send_request			receive_request
 * send_convert			receive_convert
 * send_unlock			receive_unlock
 * send_cancel			receive_cancel
 * send_grant			receive_grant
 * send_bast			receive_bast
 * send_lookup			receive_lookup
 * send_remove			receive_remove
 *
 * 				send_common_reply
 * receive_request_reply	send_request_reply
 * receive_convert_reply	send_convert_reply
 * receive_unlock_reply		send_unlock_reply
 * receive_cancel_reply		send_cancel_reply
 * receive_lookup_reply		send_lookup_reply
 */

static int _create_message(struct dlm_ls *ls, int mb_len,
			   int to_nodeid, int mstype,
			   struct dlm_message **ms_ret,
			   struct dlm_mhandle **mh_ret)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	char *mb;

	/* get_buffer gives us a message handle (mh) that we need to
	   pass into lowcomms_commit and a message buffer (mb) that we
	   write our data into */

	mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, ls->ls_allocation, &mb);
	if (!mh)
		return -ENOBUFS;

	memset(mb, 0, mb_len);

	ms = (struct dlm_message *) mb;

	ms->m_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
	ms->m_header.h_lockspace = ls->ls_global_id;
	ms->m_header.h_nodeid = dlm_our_nodeid();
	ms->m_header.h_length = mb_len;
	ms->m_header.h_cmd = DLM_MSG;

	ms->m_type = mstype;

	*mh_ret = mh;
	*ms_ret = ms;
	return 0;
}

static int create_message(struct dlm_rsb *r, struct dlm_lkb *lkb,
			  int to_nodeid, int mstype,
			  struct dlm_message **ms_ret,
			  struct dlm_mhandle **mh_ret)
{
	int mb_len = sizeof(struct dlm_message);

	switch (mstype) {
	case DLM_MSG_REQUEST:
	case DLM_MSG_LOOKUP:
	case DLM_MSG_REMOVE:
		mb_len += r->res_length;
		break;
	case DLM_MSG_CONVERT:
	case DLM_MSG_UNLOCK:
	case DLM_MSG_REQUEST_REPLY:
	case DLM_MSG_CONVERT_REPLY:
	case DLM_MSG_GRANT:
		if (lkb && lkb->lkb_lvbptr)
			mb_len += r->res_ls->ls_lvblen;
		break;
	}

	return _create_message(r->res_ls, mb_len, to_nodeid, mstype,
			       ms_ret, mh_ret);
}

/* further lowcomms enhancements or alternate implementations may make
   the return value from this function useful at some point */

static int send_message(struct dlm_mhandle *mh, struct dlm_message *ms)
{
	dlm_message_out(ms);
	dlm_lowcomms_commit_buffer(mh);
	return 0;
}

static void send_args(struct dlm_rsb *r, struct dlm_lkb *lkb,
		      struct dlm_message *ms)
{
	ms->m_nodeid   = lkb->lkb_nodeid;
	ms->m_pid      = lkb->lkb_ownpid;
	ms->m_lkid     = lkb->lkb_id;
	ms->m_remid    = lkb->lkb_remid;
	ms->m_exflags  = lkb->lkb_exflags;
	ms->m_sbflags  = lkb->lkb_sbflags;
	ms->m_flags    = lkb->lkb_flags;
	ms->m_lvbseq   = lkb->lkb_lvbseq;
	ms->m_status   = lkb->lkb_status;
	ms->m_grmode   = lkb->lkb_grmode;
	ms->m_rqmode   = lkb->lkb_rqmode;
	ms->m_hash     = r->res_hash;

	/* m_result and m_bastmode are set from function args,
	   not from lkb fields */

	if (lkb->lkb_bastaddr)
		ms->m_asts |= AST_BAST;
	if (lkb->lkb_astaddr)
		ms->m_asts |= AST_COMP;

	/* compare with switch in create_message; send_remove() doesn't
	   use send_args() */

	switch (ms->m_type) {
	case DLM_MSG_REQUEST:
	case DLM_MSG_LOOKUP:
		memcpy(ms->m_extra, r->res_name, r->res_length);
		break;
	case DLM_MSG_CONVERT:
	case DLM_MSG_UNLOCK:
	case DLM_MSG_REQUEST_REPLY:
	case DLM_MSG_CONVERT_REPLY:
	case DLM_MSG_GRANT:
		if (!lkb->lkb_lvbptr)
			break;
		memcpy(ms->m_extra, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
		break;
	}
}

static int send_common(struct dlm_rsb *r, struct dlm_lkb *lkb, int mstype)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	error = add_to_waiters(lkb, mstype);
	if (error)
		return error;

	to_nodeid = r->res_nodeid;

	error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh);
	if (error)
		goto fail;

	send_args(r, lkb, ms);

	error = send_message(mh, ms);
	if (error)
		goto fail;
	return 0;

 fail:
	remove_from_waiters(lkb, msg_reply_type(mstype));
	return error;
}

static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	return send_common(r, lkb, DLM_MSG_REQUEST);
}

static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	int error;

	error = send_common(r, lkb, DLM_MSG_CONVERT);

	/* down conversions go without a reply from the master */
	if (!error && down_conversion(lkb)) {
		remove_from_waiters(lkb, DLM_MSG_CONVERT_REPLY);
		r->res_ls->ls_stub_ms.m_type = DLM_MSG_CONVERT_REPLY;
		r->res_ls->ls_stub_ms.m_result = 0;
		r->res_ls->ls_stub_ms.m_flags = lkb->lkb_flags;
		__receive_convert_reply(r, lkb, &r->res_ls->ls_stub_ms);
	}

	return error;
}

/* FIXME: if this lkb is the only lock we hold on the rsb, then set
   MASTER_UNCERTAIN to force the next request on the rsb to confirm
   that the master is still correct. */

static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	return send_common(r, lkb, DLM_MSG_UNLOCK);
}

static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	return send_common(r, lkb, DLM_MSG_CANCEL);
}

static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	to_nodeid = lkb->lkb_nodeid;

	error = create_message(r, lkb, to_nodeid, DLM_MSG_GRANT, &ms, &mh);
	if (error)
		goto out;

	send_args(r, lkb, ms);

	ms->m_result = 0;

	error = send_message(mh, ms);
 out:
	return error;
}

static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	to_nodeid = lkb->lkb_nodeid;

	error = create_message(r, NULL, to_nodeid, DLM_MSG_BAST, &ms, &mh);
	if (error)
		goto out;

	send_args(r, lkb, ms);

	ms->m_bastmode = mode;

	error = send_message(mh, ms);
 out:
	return error;
}

static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	error = add_to_waiters(lkb, DLM_MSG_LOOKUP);
	if (error)
		return error;

	to_nodeid = dlm_dir_nodeid(r);

	error = create_message(r, NULL, to_nodeid, DLM_MSG_LOOKUP, &ms, &mh);
	if (error)
		goto fail;

	send_args(r, lkb, ms);

	error = send_message(mh, ms);
	if (error)
		goto fail;
	return 0;

 fail:
	remove_from_waiters(lkb, DLM_MSG_LOOKUP_REPLY);
	return error;
}

static int send_remove(struct dlm_rsb *r)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	to_nodeid = dlm_dir_nodeid(r);

	error = create_message(r, NULL, to_nodeid, DLM_MSG_REMOVE, &ms, &mh);
	if (error)
		goto out;

	memcpy(ms->m_extra, r->res_name, r->res_length);
	ms->m_hash = r->res_hash;

	error = send_message(mh, ms);
 out:
	return error;
}

static int send_common_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
			     int mstype, int rv)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int to_nodeid, error;

	to_nodeid = lkb->lkb_nodeid;

	error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh);
	if (error)
		goto out;

	send_args(r, lkb, ms);

	ms->m_result = rv;

	error = send_message(mh, ms);
 out:
	return error;
}

static int send_request_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
	return send_common_reply(r, lkb, DLM_MSG_REQUEST_REPLY, rv);
}

static int send_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
	return send_common_reply(r, lkb, DLM_MSG_CONVERT_REPLY, rv);
}

static int send_unlock_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
	return send_common_reply(r, lkb, DLM_MSG_UNLOCK_REPLY, rv);
}

static int send_cancel_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
	return send_common_reply(r, lkb, DLM_MSG_CANCEL_REPLY, rv);
}

static int send_lookup_reply(struct dlm_ls *ls, struct dlm_message *ms_in,
			     int ret_nodeid, int rv)
{
	struct dlm_rsb *r = &ls->ls_stub_rsb;
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int error, nodeid = ms_in->m_header.h_nodeid;

	error = create_message(r, NULL, nodeid, DLM_MSG_LOOKUP_REPLY, &ms, &mh);
	if (error)
		goto out;

	ms->m_lkid = ms_in->m_lkid;
	ms->m_result = rv;
	ms->m_nodeid = ret_nodeid;

	error = send_message(mh, ms);
 out:
	return error;
}

/* which args we save from a received message depends heavily on the type
   of message, unlike the send side where we can safely send everything about
   the lkb for any type of message */

static void receive_flags(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	lkb->lkb_exflags = ms->m_exflags;
	lkb->lkb_sbflags = ms->m_sbflags;
	lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) |
		         (ms->m_flags & 0x0000FFFF);
}

static void receive_flags_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	lkb->lkb_sbflags = ms->m_sbflags;
	lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) |
		         (ms->m_flags & 0x0000FFFF);
}

static int receive_extralen(struct dlm_message *ms)
{
	return (ms->m_header.h_length - sizeof(struct dlm_message));
}

static int receive_lvb(struct dlm_ls *ls, struct dlm_lkb *lkb,
		       struct dlm_message *ms)
{
	int len;

	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
		if (!lkb->lkb_lvbptr)
			lkb->lkb_lvbptr = allocate_lvb(ls);
		if (!lkb->lkb_lvbptr)
			return -ENOMEM;
		len = receive_extralen(ms);
		memcpy(lkb->lkb_lvbptr, ms->m_extra, len);
	}
	return 0;
}

static int receive_request_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
				struct dlm_message *ms)
{
	lkb->lkb_nodeid = ms->m_header.h_nodeid;
	lkb->lkb_ownpid = ms->m_pid;
	lkb->lkb_remid = ms->m_lkid;
	lkb->lkb_grmode = DLM_LOCK_IV;
	lkb->lkb_rqmode = ms->m_rqmode;
	lkb->lkb_bastaddr = (void *) (long) (ms->m_asts & AST_BAST);
	lkb->lkb_astaddr = (void *) (long) (ms->m_asts & AST_COMP);

	DLM_ASSERT(is_master_copy(lkb), dlm_print_lkb(lkb););

	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
		/* lkb was just created so there won't be an lvb yet */
		lkb->lkb_lvbptr = allocate_lvb(ls);
		if (!lkb->lkb_lvbptr)
			return -ENOMEM;
	}

	return 0;
}

static int receive_convert_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
				struct dlm_message *ms)
{
	if (lkb->lkb_nodeid != ms->m_header.h_nodeid) {
		log_error(ls, "convert_args nodeid %d %d lkid %x %x",
			  lkb->lkb_nodeid, ms->m_header.h_nodeid,
			  lkb->lkb_id, lkb->lkb_remid);
		return -EINVAL;
	}

	if (!is_master_copy(lkb))
		return -EINVAL;

	if (lkb->lkb_status != DLM_LKSTS_GRANTED)
		return -EBUSY;

	if (receive_lvb(ls, lkb, ms))
		return -ENOMEM;

	lkb->lkb_rqmode = ms->m_rqmode;
	lkb->lkb_lvbseq = ms->m_lvbseq;

	return 0;
}

static int receive_unlock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
			       struct dlm_message *ms)
{
	if (!is_master_copy(lkb))
		return -EINVAL;
	if (receive_lvb(ls, lkb, ms))
		return -ENOMEM;
	return 0;
}

/* We fill in the stub-lkb fields with the info that send_xxxx_reply()
   uses to send a reply and that the remote end uses to process the reply. */

static void setup_stub_lkb(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb = &ls->ls_stub_lkb;
	lkb->lkb_nodeid = ms->m_header.h_nodeid;
	lkb->lkb_remid = ms->m_lkid;
}

static void receive_request(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error, namelen;

	error = create_lkb(ls, &lkb);
	if (error)
		goto fail;

	receive_flags(lkb, ms);
	lkb->lkb_flags |= DLM_IFL_MSTCPY;
	error = receive_request_args(ls, lkb, ms);
	if (error) {
		__put_lkb(ls, lkb);
		goto fail;
	}

	namelen = receive_extralen(ms);

	error = find_rsb(ls, ms->m_extra, namelen, R_MASTER, &r);
	if (error) {
		__put_lkb(ls, lkb);
		goto fail;
	}

	lock_rsb(r);

	attach_lkb(r, lkb);
	error = do_request(r, lkb);
	send_request_reply(r, lkb, error);

	unlock_rsb(r);
	put_rsb(r);

	if (error == -EINPROGRESS)
		error = 0;
	if (error)
		dlm_put_lkb(lkb);
	return;

 fail:
	setup_stub_lkb(ls, ms);
	send_request_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
}

static void receive_convert(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error, reply = 1;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error)
		goto fail;

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	receive_flags(lkb, ms);
	error = receive_convert_args(ls, lkb, ms);
	if (error)
		goto out;
	reply = !down_conversion(lkb);

	error = do_convert(r, lkb);
 out:
	if (reply)
		send_convert_reply(r, lkb, error);

	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
	return;

 fail:
	setup_stub_lkb(ls, ms);
	send_convert_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
}

static void receive_unlock(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error)
		goto fail;

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	receive_flags(lkb, ms);
	error = receive_unlock_args(ls, lkb, ms);
	if (error)
		goto out;

	error = do_unlock(r, lkb);
 out:
	send_unlock_reply(r, lkb, error);

	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
	return;

 fail:
	setup_stub_lkb(ls, ms);
	send_unlock_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
}

static void receive_cancel(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error)
		goto fail;

	receive_flags(lkb, ms);

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	error = do_cancel(r, lkb);
	send_cancel_reply(r, lkb, error);

	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
	return;

 fail:
	setup_stub_lkb(ls, ms);
	send_cancel_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
}

static void receive_grant(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_grant no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	receive_flags_reply(lkb, ms);
	if (is_altmode(lkb))
		munge_altmode(lkb, ms);
	grant_lock_pc(r, lkb, ms);
	queue_cast(r, lkb, 0);

	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
}

static void receive_bast(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_bast no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	r = lkb->lkb_resource;

	hold_rsb(r);
	lock_rsb(r);

	queue_bast(r, lkb, ms->m_bastmode);

	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
}

static void receive_lookup(struct dlm_ls *ls, struct dlm_message *ms)
{
	int len, error, ret_nodeid, dir_nodeid, from_nodeid, our_nodeid;

	from_nodeid = ms->m_header.h_nodeid;
	our_nodeid = dlm_our_nodeid();

	len = receive_extralen(ms);

	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
	if (dir_nodeid != our_nodeid) {
		log_error(ls, "lookup dir_nodeid %d from %d",
			  dir_nodeid, from_nodeid);
		error = -EINVAL;
		ret_nodeid = -1;
		goto out;
	}

	error = dlm_dir_lookup(ls, from_nodeid, ms->m_extra, len, &ret_nodeid);

	/* Optimization: we're master so treat lookup as a request */
	if (!error && ret_nodeid == our_nodeid) {
		receive_request(ls, ms);
		return;
	}
 out:
	send_lookup_reply(ls, ms, ret_nodeid, error);
}

static void receive_remove(struct dlm_ls *ls, struct dlm_message *ms)
{
	int len, dir_nodeid, from_nodeid;

	from_nodeid = ms->m_header.h_nodeid;

	len = receive_extralen(ms);

	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
	if (dir_nodeid != dlm_our_nodeid()) {
		log_error(ls, "remove dir entry dir_nodeid %d from %d",
			  dir_nodeid, from_nodeid);
		return;
	}

	dlm_dir_remove_entry(ls, from_nodeid, ms->m_extra, len);
}

static void receive_purge(struct dlm_ls *ls, struct dlm_message *ms)
{
	do_purge(ls, ms->m_nodeid, ms->m_pid);
}

static void receive_request_reply(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error, mstype, result;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_request_reply no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	r = lkb->lkb_resource;
	hold_rsb(r);
	lock_rsb(r);

	mstype = lkb->lkb_wait_type;
	error = remove_from_waiters(lkb, DLM_MSG_REQUEST_REPLY);
	if (error)
		goto out;

	/* Optimization: the dir node was also the master, so it took our
	   lookup as a request and sent request reply instead of lookup reply */
	if (mstype == DLM_MSG_LOOKUP) {
		r->res_nodeid = ms->m_header.h_nodeid;
		lkb->lkb_nodeid = r->res_nodeid;
	}

	/* this is the value returned from do_request() on the master */
	result = ms->m_result;

	switch (result) {
	case -EAGAIN:
		/* request would block (be queued) on remote master */
		queue_cast(r, lkb, -EAGAIN);
		confirm_master(r, -EAGAIN);
		unhold_lkb(lkb); /* undoes create_lkb() */
		break;

	case -EINPROGRESS:
	case 0:
		/* request was queued or granted on remote master */
		receive_flags_reply(lkb, ms);
		lkb->lkb_remid = ms->m_lkid;
		if (is_altmode(lkb))
			munge_altmode(lkb, ms);
		if (result) {
			add_lkb(r, lkb, DLM_LKSTS_WAITING);
			add_timeout(lkb);
		} else {
			grant_lock_pc(r, lkb, ms);
			queue_cast(r, lkb, 0);
		}
		confirm_master(r, result);
		break;

	case -EBADR:
	case -ENOTBLK:
		/* find_rsb failed to find rsb or rsb wasn't master */
		log_debug(ls, "receive_request_reply %x %x master diff %d %d",
			  lkb->lkb_id, lkb->lkb_flags, r->res_nodeid, result);
		r->res_nodeid = -1;
		lkb->lkb_nodeid = -1;

		if (is_overlap(lkb)) {
			/* we'll ignore error in cancel/unlock reply */
			queue_cast_overlap(r, lkb);
			unhold_lkb(lkb); /* undoes create_lkb() */
		} else
			_request_lock(r, lkb);
		break;

	default:
		log_error(ls, "receive_request_reply %x error %d",
			  lkb->lkb_id, result);
	}

	if (is_overlap_unlock(lkb) && (result == 0 || result == -EINPROGRESS)) {
		log_debug(ls, "receive_request_reply %x result %d unlock",
			  lkb->lkb_id, result);
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
		send_unlock(r, lkb);
	} else if (is_overlap_cancel(lkb) && (result == -EINPROGRESS)) {
		log_debug(ls, "receive_request_reply %x cancel", lkb->lkb_id);
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
		send_cancel(r, lkb);
	} else {
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
	}
 out:
	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
}

static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
				    struct dlm_message *ms)
{
	/* this is the value returned from do_convert() on the master */
	switch (ms->m_result) {
	case -EAGAIN:
		/* convert would block (be queued) on remote master */
		queue_cast(r, lkb, -EAGAIN);
		break;

	case -EDEADLK:
		receive_flags_reply(lkb, ms);
		revert_lock_pc(r, lkb);
		queue_cast(r, lkb, -EDEADLK);
		break;

	case -EINPROGRESS:
		/* convert was queued on remote master */
		receive_flags_reply(lkb, ms);
		if (is_demoted(lkb))
			munge_demoted(lkb, ms);
		del_lkb(r, lkb);
		add_lkb(r, lkb, DLM_LKSTS_CONVERT);
		add_timeout(lkb);
		break;

	case 0:
		/* convert was granted on remote master */
		receive_flags_reply(lkb, ms);
		if (is_demoted(lkb))
			munge_demoted(lkb, ms);
		grant_lock_pc(r, lkb, ms);
		queue_cast(r, lkb, 0);
		break;

	default:
		log_error(r->res_ls, "receive_convert_reply %x error %d",
			  lkb->lkb_id, ms->m_result);
	}
}

static void _receive_convert_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	struct dlm_rsb *r = lkb->lkb_resource;
	int error;

	hold_rsb(r);
	lock_rsb(r);

	/* stub reply can happen with waiters_mutex held */
	error = remove_from_waiters_ms(lkb, ms);
	if (error)
		goto out;

	__receive_convert_reply(r, lkb, ms);
 out:
	unlock_rsb(r);
	put_rsb(r);
}

static void receive_convert_reply(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_convert_reply no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	_receive_convert_reply(lkb, ms);
	dlm_put_lkb(lkb);
}

static void _receive_unlock_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	struct dlm_rsb *r = lkb->lkb_resource;
	int error;

	hold_rsb(r);
	lock_rsb(r);

	/* stub reply can happen with waiters_mutex held */
	error = remove_from_waiters_ms(lkb, ms);
	if (error)
		goto out;

	/* this is the value returned from do_unlock() on the master */

	switch (ms->m_result) {
	case -DLM_EUNLOCK:
		receive_flags_reply(lkb, ms);
		remove_lock_pc(r, lkb);
		queue_cast(r, lkb, -DLM_EUNLOCK);
		break;
	case -ENOENT:
		break;
	default:
		log_error(r->res_ls, "receive_unlock_reply %x error %d",
			  lkb->lkb_id, ms->m_result);
	}
 out:
	unlock_rsb(r);
	put_rsb(r);
}

static void receive_unlock_reply(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_unlock_reply no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	_receive_unlock_reply(lkb, ms);
	dlm_put_lkb(lkb);
}

static void _receive_cancel_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
{
	struct dlm_rsb *r = lkb->lkb_resource;
	int error;

	hold_rsb(r);
	lock_rsb(r);

	/* stub reply can happen with waiters_mutex held */
	error = remove_from_waiters_ms(lkb, ms);
	if (error)
		goto out;

	/* this is the value returned from do_cancel() on the master */

	switch (ms->m_result) {
	case -DLM_ECANCEL:
		receive_flags_reply(lkb, ms);
		revert_lock_pc(r, lkb);
		queue_cast(r, lkb, -DLM_ECANCEL);
		break;
	case 0:
		break;
	default:
		log_error(r->res_ls, "receive_cancel_reply %x error %d",
			  lkb->lkb_id, ms->m_result);
	}
 out:
	unlock_rsb(r);
	put_rsb(r);
}

static void receive_cancel_reply(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	int error;

	error = find_lkb(ls, ms->m_remid, &lkb);
	if (error) {
		log_error(ls, "receive_cancel_reply no lkb");
		return;
	}
	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	_receive_cancel_reply(lkb, ms);
	dlm_put_lkb(lkb);
}

static void receive_lookup_reply(struct dlm_ls *ls, struct dlm_message *ms)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error, ret_nodeid;

	error = find_lkb(ls, ms->m_lkid, &lkb);
	if (error) {
		log_error(ls, "receive_lookup_reply no lkb");
		return;
	}

	/* ms->m_result is the value returned by dlm_dir_lookup on dir node
	   FIXME: will a non-zero error ever be returned? */

	r = lkb->lkb_resource;
	hold_rsb(r);
	lock_rsb(r);

	error = remove_from_waiters(lkb, DLM_MSG_LOOKUP_REPLY);
	if (error)
		goto out;

	ret_nodeid = ms->m_nodeid;
	if (ret_nodeid == dlm_our_nodeid()) {
		r->res_nodeid = 0;
		ret_nodeid = 0;
		r->res_first_lkid = 0;
	} else {
		/* set_master() will copy res_nodeid to lkb_nodeid */
		r->res_nodeid = ret_nodeid;
	}

	if (is_overlap(lkb)) {
		log_debug(ls, "receive_lookup_reply %x unlock %x",
			  lkb->lkb_id, lkb->lkb_flags);
		queue_cast_overlap(r, lkb);
		unhold_lkb(lkb); /* undoes create_lkb() */
		goto out_list;
	}

	_request_lock(r, lkb);

 out_list:
	if (!ret_nodeid)
		process_lookup_list(r);
 out:
	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);
}

static void _receive_message(struct dlm_ls *ls, struct dlm_message *ms)
{
	switch (ms->m_type) {

	/* messages sent to a master node */

	case DLM_MSG_REQUEST:
		receive_request(ls, ms);
		break;

	case DLM_MSG_CONVERT:
		receive_convert(ls, ms);
		break;

	case DLM_MSG_UNLOCK:
		receive_unlock(ls, ms);
		break;

	case DLM_MSG_CANCEL:
		receive_cancel(ls, ms);
		break;

	/* messages sent from a master node (replies to above) */

	case DLM_MSG_REQUEST_REPLY:
		receive_request_reply(ls, ms);
		break;

	case DLM_MSG_CONVERT_REPLY:
		receive_convert_reply(ls, ms);
		break;

	case DLM_MSG_UNLOCK_REPLY:
		receive_unlock_reply(ls, ms);
		break;

	case DLM_MSG_CANCEL_REPLY:
		receive_cancel_reply(ls, ms);
		break;

	/* messages sent from a master node (only two types of async msg) */

	case DLM_MSG_GRANT:
		receive_grant(ls, ms);
		break;

	case DLM_MSG_BAST:
		receive_bast(ls, ms);
		break;

	/* messages sent to a dir node */

	case DLM_MSG_LOOKUP:
		receive_lookup(ls, ms);
		break;

	case DLM_MSG_REMOVE:
		receive_remove(ls, ms);
		break;

	/* messages sent from a dir node (remove has no reply) */

	case DLM_MSG_LOOKUP_REPLY:
		receive_lookup_reply(ls, ms);
		break;

	/* other messages */

	case DLM_MSG_PURGE:
		receive_purge(ls, ms);
		break;

	default:
		log_error(ls, "unknown message type %d", ms->m_type);
	}

	dlm_astd_wake();
}

/* If the lockspace is in recovery mode (locking stopped), then normal
   messages are saved on the requestqueue for processing after recovery is
   done.  When not in recovery mode, we wait for dlm_recoverd to drain saved
   messages off the requestqueue before we process new ones. This occurs right
   after recovery completes when we transition from saving all messages on
   requestqueue, to processing all the saved messages, to processing new
   messages as they arrive. */

static void dlm_receive_message(struct dlm_ls *ls, struct dlm_message *ms,
				int nodeid)
{
	if (dlm_locking_stopped(ls)) {
		dlm_add_requestqueue(ls, nodeid, (struct dlm_header *) ms);
	} else {
		dlm_wait_requestqueue(ls);
		_receive_message(ls, ms);
	}
}

/* This is called by dlm_recoverd to process messages that were saved on
   the requestqueue. */

void dlm_receive_message_saved(struct dlm_ls *ls, struct dlm_message *ms)
{
	_receive_message(ls, ms);
}

/* This is called by the midcomms layer when something is received for
   the lockspace.  It could be either a MSG (normal message sent as part of
   standard locking activity) or an RCOM (recovery message sent as part of
   lockspace recovery). */

void dlm_receive_buffer(struct dlm_header *hd, int nodeid)
{
	struct dlm_message *ms = (struct dlm_message *) hd;
	struct dlm_rcom *rc = (struct dlm_rcom *) hd;
	struct dlm_ls *ls;
	int type = 0;

	switch (hd->h_cmd) {
	case DLM_MSG:
		dlm_message_in(ms);
		type = ms->m_type;
		break;
	case DLM_RCOM:
		dlm_rcom_in(rc);
		type = rc->rc_type;
		break;
	default:
		log_print("invalid h_cmd %d from %u", hd->h_cmd, nodeid);
		return;
	}

	if (hd->h_nodeid != nodeid) {
		log_print("invalid h_nodeid %d from %d lockspace %x",
			  hd->h_nodeid, nodeid, hd->h_lockspace);
		return;
	}

	ls = dlm_find_lockspace_global(hd->h_lockspace);
	if (!ls) {
		log_print("invalid h_lockspace %x from %d cmd %d type %d",
			  hd->h_lockspace, nodeid, hd->h_cmd, type);

		if (hd->h_cmd == DLM_RCOM && type == DLM_RCOM_STATUS)
			dlm_send_ls_not_ready(nodeid, rc);
		return;
	}

	/* this rwsem allows dlm_ls_stop() to wait for all dlm_recv threads to
	   be inactive (in this ls) before transitioning to recovery mode */

	down_read(&ls->ls_recv_active);
	if (hd->h_cmd == DLM_MSG)
		dlm_receive_message(ls, ms, nodeid);
	else
		dlm_receive_rcom(ls, rc, nodeid);
	up_read(&ls->ls_recv_active);

	dlm_put_lockspace(ls);
}

static void recover_convert_waiter(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	if (middle_conversion(lkb)) {
		hold_lkb(lkb);
		ls->ls_stub_ms.m_type = DLM_MSG_CONVERT_REPLY;
		ls->ls_stub_ms.m_result = -EINPROGRESS;
		ls->ls_stub_ms.m_flags = lkb->lkb_flags;
		_receive_convert_reply(lkb, &ls->ls_stub_ms);

		/* Same special case as in receive_rcom_lock_args() */
		lkb->lkb_grmode = DLM_LOCK_IV;
		rsb_set_flag(lkb->lkb_resource, RSB_RECOVER_CONVERT);
		unhold_lkb(lkb);

	} else if (lkb->lkb_rqmode >= lkb->lkb_grmode) {
		lkb->lkb_flags |= DLM_IFL_RESEND;
	}

	/* lkb->lkb_rqmode < lkb->lkb_grmode shouldn't happen since down
	   conversions are async; there's no reply from the remote master */
}

/* A waiting lkb needs recovery if the master node has failed, or
   the master node is changing (only when no directory is used) */

static int waiter_needs_recovery(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	if (dlm_is_removed(ls, lkb->lkb_nodeid))
		return 1;

	if (!dlm_no_directory(ls))
		return 0;

	if (dlm_dir_nodeid(lkb->lkb_resource) != lkb->lkb_nodeid)
		return 1;

	return 0;
}

/* Recovery for locks that are waiting for replies from nodes that are now
   gone.  We can just complete unlocks and cancels by faking a reply from the
   dead node.  Requests and up-conversions we flag to be resent after
   recovery.  Down-conversions can just be completed with a fake reply like
   unlocks.  Conversions between PR and CW need special attention. */

void dlm_recover_waiters_pre(struct dlm_ls *ls)
{
	struct dlm_lkb *lkb, *safe;

	mutex_lock(&ls->ls_waiters_mutex);

	list_for_each_entry_safe(lkb, safe, &ls->ls_waiters, lkb_wait_reply) {
		log_debug(ls, "pre recover waiter lkid %x type %d flags %x",
			  lkb->lkb_id, lkb->lkb_wait_type, lkb->lkb_flags);

		/* all outstanding lookups, regardless of destination  will be
		   resent after recovery is done */

		if (lkb->lkb_wait_type == DLM_MSG_LOOKUP) {
			lkb->lkb_flags |= DLM_IFL_RESEND;
			continue;
		}

		if (!waiter_needs_recovery(ls, lkb))
			continue;

		switch (lkb->lkb_wait_type) {

		case DLM_MSG_REQUEST:
			lkb->lkb_flags |= DLM_IFL_RESEND;
			break;

		case DLM_MSG_CONVERT:
			recover_convert_waiter(ls, lkb);
			break;

		case DLM_MSG_UNLOCK:
			hold_lkb(lkb);
			ls->ls_stub_ms.m_type = DLM_MSG_UNLOCK_REPLY;
			ls->ls_stub_ms.m_result = -DLM_EUNLOCK;
			ls->ls_stub_ms.m_flags = lkb->lkb_flags;
			_receive_unlock_reply(lkb, &ls->ls_stub_ms);
			dlm_put_lkb(lkb);
			break;

		case DLM_MSG_CANCEL:
			hold_lkb(lkb);
			ls->ls_stub_ms.m_type = DLM_MSG_CANCEL_REPLY;
			ls->ls_stub_ms.m_result = -DLM_ECANCEL;
			ls->ls_stub_ms.m_flags = lkb->lkb_flags;
			_receive_cancel_reply(lkb, &ls->ls_stub_ms);
			dlm_put_lkb(lkb);
			break;

		default:
			log_error(ls, "invalid lkb wait_type %d",
				  lkb->lkb_wait_type);
		}
		schedule();
	}
	mutex_unlock(&ls->ls_waiters_mutex);
}

static struct dlm_lkb *find_resend_waiter(struct dlm_ls *ls)
{
	struct dlm_lkb *lkb;
	int found = 0;

	mutex_lock(&ls->ls_waiters_mutex);
	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
		if (lkb->lkb_flags & DLM_IFL_RESEND) {
			hold_lkb(lkb);
			found = 1;
			break;
		}
	}
	mutex_unlock(&ls->ls_waiters_mutex);

	if (!found)
		lkb = NULL;
	return lkb;
}

/* Deal with lookups and lkb's marked RESEND from _pre.  We may now be the
   master or dir-node for r.  Processing the lkb may result in it being placed
   back on waiters. */

/* We do this after normal locking has been enabled and any saved messages
   (in requestqueue) have been processed.  We should be confident that at
   this point we won't get or process a reply to any of these waiting
   operations.  But, new ops may be coming in on the rsbs/locks here from
   userspace or remotely. */

/* there may have been an overlap unlock/cancel prior to recovery or after
   recovery.  if before, the lkb may still have a pos wait_count; if after, the
   overlap flag would just have been set and nothing new sent.  we can be
   confident here than any replies to either the initial op or overlap ops
   prior to recovery have been received. */

int dlm_recover_waiters_post(struct dlm_ls *ls)
{
	struct dlm_lkb *lkb;
	struct dlm_rsb *r;
	int error = 0, mstype, err, oc, ou;

	while (1) {
		if (dlm_locking_stopped(ls)) {
			log_debug(ls, "recover_waiters_post aborted");
			error = -EINTR;
			break;
		}

		lkb = find_resend_waiter(ls);
		if (!lkb)
			break;

		r = lkb->lkb_resource;
		hold_rsb(r);
		lock_rsb(r);

		mstype = lkb->lkb_wait_type;
		oc = is_overlap_cancel(lkb);
		ou = is_overlap_unlock(lkb);
		err = 0;

		log_debug(ls, "recover_waiters_post %x type %d flags %x %s",
			  lkb->lkb_id, mstype, lkb->lkb_flags, r->res_name);

		/* At this point we assume that we won't get a reply to any
		   previous op or overlap op on this lock.  First, do a big
		   remove_from_waiters() for all previous ops. */

		lkb->lkb_flags &= ~DLM_IFL_RESEND;
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
		lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
		lkb->lkb_wait_type = 0;
		lkb->lkb_wait_count = 0;
		mutex_lock(&ls->ls_waiters_mutex);
		list_del_init(&lkb->lkb_wait_reply);
		mutex_unlock(&ls->ls_waiters_mutex);
		unhold_lkb(lkb); /* for waiters list */

		if (oc || ou) {
			/* do an unlock or cancel instead of resending */
			switch (mstype) {
			case DLM_MSG_LOOKUP:
			case DLM_MSG_REQUEST:
				queue_cast(r, lkb, ou ? -DLM_EUNLOCK :
							-DLM_ECANCEL);
				unhold_lkb(lkb); /* undoes create_lkb() */
				break;
			case DLM_MSG_CONVERT:
				if (oc) {
					queue_cast(r, lkb, -DLM_ECANCEL);
				} else {
					lkb->lkb_exflags |= DLM_LKF_FORCEUNLOCK;
					_unlock_lock(r, lkb);
				}
				break;
			default:
				err = 1;
			}
		} else {
			switch (mstype) {
			case DLM_MSG_LOOKUP:
			case DLM_MSG_REQUEST:
				_request_lock(r, lkb);
				if (is_master(r))
					confirm_master(r, 0);
				break;
			case DLM_MSG_CONVERT:
				_convert_lock(r, lkb);
				break;
			default:
				err = 1;
			}
		}

		if (err)
			log_error(ls, "recover_waiters_post %x %d %x %d %d",
			  	  lkb->lkb_id, mstype, lkb->lkb_flags, oc, ou);
		unlock_rsb(r);
		put_rsb(r);
		dlm_put_lkb(lkb);
	}

	return error;
}

static void purge_queue(struct dlm_rsb *r, struct list_head *queue,
			int (*test)(struct dlm_ls *ls, struct dlm_lkb *lkb))
{
	struct dlm_ls *ls = r->res_ls;
	struct dlm_lkb *lkb, *safe;

	list_for_each_entry_safe(lkb, safe, queue, lkb_statequeue) {
		if (test(ls, lkb)) {
			rsb_set_flag(r, RSB_LOCKS_PURGED);
			del_lkb(r, lkb);
			/* this put should free the lkb */
			if (!dlm_put_lkb(lkb))
				log_error(ls, "purged lkb not released");
		}
	}
}

static int purge_dead_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	return (is_master_copy(lkb) && dlm_is_removed(ls, lkb->lkb_nodeid));
}

static int purge_mstcpy_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	return is_master_copy(lkb);
}

static void purge_dead_locks(struct dlm_rsb *r)
{
	purge_queue(r, &r->res_grantqueue, &purge_dead_test);
	purge_queue(r, &r->res_convertqueue, &purge_dead_test);
	purge_queue(r, &r->res_waitqueue, &purge_dead_test);
}

void dlm_purge_mstcpy_locks(struct dlm_rsb *r)
{
	purge_queue(r, &r->res_grantqueue, &purge_mstcpy_test);
	purge_queue(r, &r->res_convertqueue, &purge_mstcpy_test);
	purge_queue(r, &r->res_waitqueue, &purge_mstcpy_test);
}

/* Get rid of locks held by nodes that are gone. */

int dlm_purge_locks(struct dlm_ls *ls)
{
	struct dlm_rsb *r;

	log_debug(ls, "dlm_purge_locks");

	down_write(&ls->ls_root_sem);
	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
		hold_rsb(r);
		lock_rsb(r);
		if (is_master(r))
			purge_dead_locks(r);
		unlock_rsb(r);
		unhold_rsb(r);

		schedule();
	}
	up_write(&ls->ls_root_sem);

	return 0;
}

static struct dlm_rsb *find_purged_rsb(struct dlm_ls *ls, int bucket)
{
	struct dlm_rsb *r, *r_ret = NULL;

	read_lock(&ls->ls_rsbtbl[bucket].lock);
	list_for_each_entry(r, &ls->ls_rsbtbl[bucket].list, res_hashchain) {
		if (!rsb_flag(r, RSB_LOCKS_PURGED))
			continue;
		hold_rsb(r);
		rsb_clear_flag(r, RSB_LOCKS_PURGED);
		r_ret = r;
		break;
	}
	read_unlock(&ls->ls_rsbtbl[bucket].lock);
	return r_ret;
}

void dlm_grant_after_purge(struct dlm_ls *ls)
{
	struct dlm_rsb *r;
	int bucket = 0;

	while (1) {
		r = find_purged_rsb(ls, bucket);
		if (!r) {
			if (bucket == ls->ls_rsbtbl_size - 1)
				break;
			bucket++;
			continue;
		}
		lock_rsb(r);
		if (is_master(r)) {
			grant_pending_locks(r);
			confirm_master(r, 0);
		}
		unlock_rsb(r);
		put_rsb(r);
		schedule();
	}
}

static struct dlm_lkb *search_remid_list(struct list_head *head, int nodeid,
					 uint32_t remid)
{
	struct dlm_lkb *lkb;

	list_for_each_entry(lkb, head, lkb_statequeue) {
		if (lkb->lkb_nodeid == nodeid && lkb->lkb_remid == remid)
			return lkb;
	}
	return NULL;
}

static struct dlm_lkb *search_remid(struct dlm_rsb *r, int nodeid,
				    uint32_t remid)
{
	struct dlm_lkb *lkb;

	lkb = search_remid_list(&r->res_grantqueue, nodeid, remid);
	if (lkb)
		return lkb;
	lkb = search_remid_list(&r->res_convertqueue, nodeid, remid);
	if (lkb)
		return lkb;
	lkb = search_remid_list(&r->res_waitqueue, nodeid, remid);
	if (lkb)
		return lkb;
	return NULL;
}

static int receive_rcom_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
				  struct dlm_rsb *r, struct dlm_rcom *rc)
{
	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
	int lvblen;

	lkb->lkb_nodeid = rc->rc_header.h_nodeid;
	lkb->lkb_ownpid = rl->rl_ownpid;
	lkb->lkb_remid = rl->rl_lkid;
	lkb->lkb_exflags = rl->rl_exflags;
	lkb->lkb_flags = rl->rl_flags & 0x0000FFFF;
	lkb->lkb_flags |= DLM_IFL_MSTCPY;
	lkb->lkb_lvbseq = rl->rl_lvbseq;
	lkb->lkb_rqmode = rl->rl_rqmode;
	lkb->lkb_grmode = rl->rl_grmode;
	/* don't set lkb_status because add_lkb wants to itself */

	lkb->lkb_bastaddr = (void *) (long) (rl->rl_asts & AST_BAST);
	lkb->lkb_astaddr = (void *) (long) (rl->rl_asts & AST_COMP);

	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
		lkb->lkb_lvbptr = allocate_lvb(ls);
		if (!lkb->lkb_lvbptr)
			return -ENOMEM;
		lvblen = rc->rc_header.h_length - sizeof(struct dlm_rcom) -
			 sizeof(struct rcom_lock);
		memcpy(lkb->lkb_lvbptr, rl->rl_lvb, lvblen);
	}

	/* Conversions between PR and CW (middle modes) need special handling.
	   The real granted mode of these converting locks cannot be determined
	   until all locks have been rebuilt on the rsb (recover_conversion) */

	if (rl->rl_wait_type == DLM_MSG_CONVERT && middle_conversion(lkb)) {
		rl->rl_status = DLM_LKSTS_CONVERT;
		lkb->lkb_grmode = DLM_LOCK_IV;
		rsb_set_flag(r, RSB_RECOVER_CONVERT);
	}

	return 0;
}

/* This lkb may have been recovered in a previous aborted recovery so we need
   to check if the rsb already has an lkb with the given remote nodeid/lkid.
   If so we just send back a standard reply.  If not, we create a new lkb with
   the given values and send back our lkid.  We send back our lkid by sending
   back the rcom_lock struct we got but with the remid field filled in. */

int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
{
	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
	struct dlm_rsb *r;
	struct dlm_lkb *lkb;
	int error;

	if (rl->rl_parent_lkid) {
		error = -EOPNOTSUPP;
		goto out;
	}

	error = find_rsb(ls, rl->rl_name, rl->rl_namelen, R_MASTER, &r);
	if (error)
		goto out;

	lock_rsb(r);

	lkb = search_remid(r, rc->rc_header.h_nodeid, rl->rl_lkid);
	if (lkb) {
		error = -EEXIST;
		goto out_remid;
	}

	error = create_lkb(ls, &lkb);
	if (error)
		goto out_unlock;

	error = receive_rcom_lock_args(ls, lkb, r, rc);
	if (error) {
		__put_lkb(ls, lkb);
		goto out_unlock;
	}

	attach_lkb(r, lkb);
	add_lkb(r, lkb, rl->rl_status);
	error = 0;

 out_remid:
	/* this is the new value returned to the lock holder for
	   saving in its process-copy lkb */
	rl->rl_remid = lkb->lkb_id;

 out_unlock:
	unlock_rsb(r);
	put_rsb(r);
 out:
	if (error)
		log_print("recover_master_copy %d %x", error, rl->rl_lkid);
	rl->rl_result = error;
	return error;
}

int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
{
	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
	struct dlm_rsb *r;
	struct dlm_lkb *lkb;
	int error;

	error = find_lkb(ls, rl->rl_lkid, &lkb);
	if (error) {
		log_error(ls, "recover_process_copy no lkid %x", rl->rl_lkid);
		return error;
	}

	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););

	error = rl->rl_result;

	r = lkb->lkb_resource;
	hold_rsb(r);
	lock_rsb(r);

	switch (error) {
	case -EBADR:
		/* There's a chance the new master received our lock before
		   dlm_recover_master_reply(), this wouldn't happen if we did
		   a barrier between recover_masters and recover_locks. */
		log_debug(ls, "master copy not ready %x r %lx %s", lkb->lkb_id,
			  (unsigned long)r, r->res_name);
		dlm_send_rcom_lock(r, lkb);
		goto out;
	case -EEXIST:
		log_debug(ls, "master copy exists %x", lkb->lkb_id);
		/* fall through */
	case 0:
		lkb->lkb_remid = rl->rl_remid;
		break;
	default:
		log_error(ls, "dlm_recover_process_copy unknown error %d %x",
			  error, lkb->lkb_id);
	}

	/* an ack for dlm_recover_locks() which waits for replies from
	   all the locks it sends to new masters */
	dlm_recovered_lock(r);
 out:
	unlock_rsb(r);
	put_rsb(r);
	dlm_put_lkb(lkb);

	return 0;
}

int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
		     int mode, uint32_t flags, void *name, unsigned int namelen,
		     unsigned long timeout_cs)
{
	struct dlm_lkb *lkb;
	struct dlm_args args;
	int error;

	dlm_lock_recovery(ls);

	error = create_lkb(ls, &lkb);
	if (error) {
		kfree(ua);
		goto out;
	}

	if (flags & DLM_LKF_VALBLK) {
		ua->lksb.sb_lvbptr = kzalloc(DLM_USER_LVB_LEN, GFP_KERNEL);
		if (!ua->lksb.sb_lvbptr) {
			kfree(ua);
			__put_lkb(ls, lkb);
			error = -ENOMEM;
			goto out;
		}
	}

	/* After ua is attached to lkb it will be freed by free_lkb().
	   When DLM_IFL_USER is set, the dlm knows that this is a userspace
	   lock and that lkb_astparam is the dlm_user_args structure. */

	error = set_lock_args(mode, &ua->lksb, flags, namelen, timeout_cs,
			      DLM_FAKE_USER_AST, ua, DLM_FAKE_USER_AST, &args);
	lkb->lkb_flags |= DLM_IFL_USER;
	ua->old_mode = DLM_LOCK_IV;

	if (error) {
		__put_lkb(ls, lkb);
		goto out;
	}

	error = request_lock(ls, lkb, name, namelen, &args);

	switch (error) {
	case 0:
		break;
	case -EINPROGRESS:
		error = 0;
		break;
	case -EAGAIN:
		error = 0;
		/* fall through */
	default:
		__put_lkb(ls, lkb);
		goto out;
	}

	/* add this new lkb to the per-process list of locks */
	spin_lock(&ua->proc->locks_spin);
	hold_lkb(lkb);
	list_add_tail(&lkb->lkb_ownqueue, &ua->proc->locks);
	spin_unlock(&ua->proc->locks_spin);
 out:
	dlm_unlock_recovery(ls);
	return error;
}

int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
		     int mode, uint32_t flags, uint32_t lkid, char *lvb_in,
		     unsigned long timeout_cs)
{
	struct dlm_lkb *lkb;
	struct dlm_args args;
	struct dlm_user_args *ua;
	int error;

	dlm_lock_recovery(ls);

	error = find_lkb(ls, lkid, &lkb);
	if (error)
		goto out;

	/* user can change the params on its lock when it converts it, or
	   add an lvb that didn't exist before */

	ua = (struct dlm_user_args *)lkb->lkb_astparam;

	if (flags & DLM_LKF_VALBLK && !ua->lksb.sb_lvbptr) {
		ua->lksb.sb_lvbptr = kzalloc(DLM_USER_LVB_LEN, GFP_KERNEL);
		if (!ua->lksb.sb_lvbptr) {
			error = -ENOMEM;
			goto out_put;
		}
	}
	if (lvb_in && ua->lksb.sb_lvbptr)
		memcpy(ua->lksb.sb_lvbptr, lvb_in, DLM_USER_LVB_LEN);

	ua->xid = ua_tmp->xid;
	ua->castparam = ua_tmp->castparam;
	ua->castaddr = ua_tmp->castaddr;
	ua->bastparam = ua_tmp->bastparam;
	ua->bastaddr = ua_tmp->bastaddr;
	ua->user_lksb = ua_tmp->user_lksb;
	ua->old_mode = lkb->lkb_grmode;

	error = set_lock_args(mode, &ua->lksb, flags, 0, timeout_cs,
			      DLM_FAKE_USER_AST, ua, DLM_FAKE_USER_AST, &args);
	if (error)
		goto out_put;

	error = convert_lock(ls, lkb, &args);

	if (error == -EINPROGRESS || error == -EAGAIN || error == -EDEADLK)
		error = 0;
 out_put:
	dlm_put_lkb(lkb);
 out:
	dlm_unlock_recovery(ls);
	kfree(ua_tmp);
	return error;
}

int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
		    uint32_t flags, uint32_t lkid, char *lvb_in)
{
	struct dlm_lkb *lkb;
	struct dlm_args args;
	struct dlm_user_args *ua;
	int error;

	dlm_lock_recovery(ls);

	error = find_lkb(ls, lkid, &lkb);
	if (error)
		goto out;

	ua = (struct dlm_user_args *)lkb->lkb_astparam;

	if (lvb_in && ua->lksb.sb_lvbptr)
		memcpy(ua->lksb.sb_lvbptr, lvb_in, DLM_USER_LVB_LEN);
	if (ua_tmp->castparam)
		ua->castparam = ua_tmp->castparam;
	ua->user_lksb = ua_tmp->user_lksb;

	error = set_unlock_args(flags, ua, &args);
	if (error)
		goto out_put;

	error = unlock_lock(ls, lkb, &args);

	if (error == -DLM_EUNLOCK)
		error = 0;
	/* from validate_unlock_args() */
	if (error == -EBUSY && (flags & DLM_LKF_FORCEUNLOCK))
		error = 0;
	if (error)
		goto out_put;

	spin_lock(&ua->proc->locks_spin);
	/* dlm_user_add_ast() may have already taken lkb off the proc list */
	if (!list_empty(&lkb->lkb_ownqueue))
		list_move(&lkb->lkb_ownqueue, &ua->proc->unlocking);
	spin_unlock(&ua->proc->locks_spin);
 out_put:
	dlm_put_lkb(lkb);
 out:
	dlm_unlock_recovery(ls);
	kfree(ua_tmp);
	return error;
}

int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
		    uint32_t flags, uint32_t lkid)
{
	struct dlm_lkb *lkb;
	struct dlm_args args;
	struct dlm_user_args *ua;
	int error;

	dlm_lock_recovery(ls);

	error = find_lkb(ls, lkid, &lkb);
	if (error)
		goto out;

	ua = (struct dlm_user_args *)lkb->lkb_astparam;
	if (ua_tmp->castparam)
		ua->castparam = ua_tmp->castparam;
	ua->user_lksb = ua_tmp->user_lksb;

	error = set_unlock_args(flags, ua, &args);
	if (error)
		goto out_put;

	error = cancel_lock(ls, lkb, &args);

	if (error == -DLM_ECANCEL)
		error = 0;
	/* from validate_unlock_args() */
	if (error == -EBUSY)
		error = 0;
 out_put:
	dlm_put_lkb(lkb);
 out:
	dlm_unlock_recovery(ls);
	kfree(ua_tmp);
	return error;
}

int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid)
{
	struct dlm_lkb *lkb;
	struct dlm_args args;
	struct dlm_user_args *ua;
	struct dlm_rsb *r;
	int error;

	dlm_lock_recovery(ls);

	error = find_lkb(ls, lkid, &lkb);
	if (error)
		goto out;

	ua = (struct dlm_user_args *)lkb->lkb_astparam;

	error = set_unlock_args(flags, ua, &args);
	if (error)
		goto out_put;

	/* same as cancel_lock(), but set DEADLOCK_CANCEL after lock_rsb */

	r = lkb->lkb_resource;
	hold_rsb(r);
	lock_rsb(r);

	error = validate_unlock_args(lkb, &args);
	if (error)
		goto out_r;
	lkb->lkb_flags |= DLM_IFL_DEADLOCK_CANCEL;

	error = _cancel_lock(r, lkb);
 out_r:
	unlock_rsb(r);
	put_rsb(r);

	if (error == -DLM_ECANCEL)
		error = 0;
	/* from validate_unlock_args() */
	if (error == -EBUSY)
		error = 0;
 out_put:
	dlm_put_lkb(lkb);
 out:
	dlm_unlock_recovery(ls);
	return error;
}

/* lkb's that are removed from the waiters list by revert are just left on the
   orphans list with the granted orphan locks, to be freed by purge */

static int orphan_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	struct dlm_user_args *ua = (struct dlm_user_args *)lkb->lkb_astparam;
	struct dlm_args args;
	int error;

	hold_lkb(lkb);
	mutex_lock(&ls->ls_orphans_mutex);
	list_add_tail(&lkb->lkb_ownqueue, &ls->ls_orphans);
	mutex_unlock(&ls->ls_orphans_mutex);

	set_unlock_args(0, ua, &args);

	error = cancel_lock(ls, lkb, &args);
	if (error == -DLM_ECANCEL)
		error = 0;
	return error;
}

/* The force flag allows the unlock to go ahead even if the lkb isn't granted.
   Regardless of what rsb queue the lock is on, it's removed and freed. */

static int unlock_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb)
{
	struct dlm_user_args *ua = (struct dlm_user_args *)lkb->lkb_astparam;
	struct dlm_args args;
	int error;

	set_unlock_args(DLM_LKF_FORCEUNLOCK, ua, &args);

	error = unlock_lock(ls, lkb, &args);
	if (error == -DLM_EUNLOCK)
		error = 0;
	return error;
}

/* We have to release clear_proc_locks mutex before calling unlock_proc_lock()
   (which does lock_rsb) due to deadlock with receiving a message that does
   lock_rsb followed by dlm_user_add_ast() */

static struct dlm_lkb *del_proc_lock(struct dlm_ls *ls,
				     struct dlm_user_proc *proc)
{
	struct dlm_lkb *lkb = NULL;

	mutex_lock(&ls->ls_clear_proc_locks);
	if (list_empty(&proc->locks))
		goto out;

	lkb = list_entry(proc->locks.next, struct dlm_lkb, lkb_ownqueue);
	list_del_init(&lkb->lkb_ownqueue);

	if (lkb->lkb_exflags & DLM_LKF_PERSISTENT)
		lkb->lkb_flags |= DLM_IFL_ORPHAN;
	else
		lkb->lkb_flags |= DLM_IFL_DEAD;
 out:
	mutex_unlock(&ls->ls_clear_proc_locks);
	return lkb;
}

/* The ls_clear_proc_locks mutex protects against dlm_user_add_asts() which
   1) references lkb->ua which we free here and 2) adds lkbs to proc->asts,
   which we clear here. */

/* proc CLOSING flag is set so no more device_reads should look at proc->asts
   list, and no more device_writes should add lkb's to proc->locks list; so we
   shouldn't need to take asts_spin or locks_spin here.  this assumes that
   device reads/writes/closes are serialized -- FIXME: we may need to serialize
   them ourself. */

void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc)
{
	struct dlm_lkb *lkb, *safe;

	dlm_lock_recovery(ls);

	while (1) {
		lkb = del_proc_lock(ls, proc);
		if (!lkb)
			break;
		del_timeout(lkb);
		if (lkb->lkb_exflags & DLM_LKF_PERSISTENT)
			orphan_proc_lock(ls, lkb);
		else
			unlock_proc_lock(ls, lkb);

		/* this removes the reference for the proc->locks list
		   added by dlm_user_request, it may result in the lkb
		   being freed */

		dlm_put_lkb(lkb);
	}

	mutex_lock(&ls->ls_clear_proc_locks);

	/* in-progress unlocks */
	list_for_each_entry_safe(lkb, safe, &proc->unlocking, lkb_ownqueue) {
		list_del_init(&lkb->lkb_ownqueue);
		lkb->lkb_flags |= DLM_IFL_DEAD;
		dlm_put_lkb(lkb);
	}

	list_for_each_entry_safe(lkb, safe, &proc->asts, lkb_astqueue) {
		list_del(&lkb->lkb_astqueue);
		dlm_put_lkb(lkb);
	}

	mutex_unlock(&ls->ls_clear_proc_locks);
	dlm_unlock_recovery(ls);
}

static void purge_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc)
{
	struct dlm_lkb *lkb, *safe;

	while (1) {
		lkb = NULL;
		spin_lock(&proc->locks_spin);
		if (!list_empty(&proc->locks)) {
			lkb = list_entry(proc->locks.next, struct dlm_lkb,
					 lkb_ownqueue);
			list_del_init(&lkb->lkb_ownqueue);
		}
		spin_unlock(&proc->locks_spin);

		if (!lkb)
			break;

		lkb->lkb_flags |= DLM_IFL_DEAD;
		unlock_proc_lock(ls, lkb);
		dlm_put_lkb(lkb); /* ref from proc->locks list */
	}

	spin_lock(&proc->locks_spin);
	list_for_each_entry_safe(lkb, safe, &proc->unlocking, lkb_ownqueue) {
		list_del_init(&lkb->lkb_ownqueue);
		lkb->lkb_flags |= DLM_IFL_DEAD;
		dlm_put_lkb(lkb);
	}
	spin_unlock(&proc->locks_spin);

	spin_lock(&proc->asts_spin);
	list_for_each_entry_safe(lkb, safe, &proc->asts, lkb_astqueue) {
		list_del(&lkb->lkb_astqueue);
		dlm_put_lkb(lkb);
	}
	spin_unlock(&proc->asts_spin);
}

/* pid of 0 means purge all orphans */

static void do_purge(struct dlm_ls *ls, int nodeid, int pid)
{
	struct dlm_lkb *lkb, *safe;

	mutex_lock(&ls->ls_orphans_mutex);
	list_for_each_entry_safe(lkb, safe, &ls->ls_orphans, lkb_ownqueue) {
		if (pid && lkb->lkb_ownpid != pid)
			continue;
		unlock_proc_lock(ls, lkb);
		list_del_init(&lkb->lkb_ownqueue);
		dlm_put_lkb(lkb);
	}
	mutex_unlock(&ls->ls_orphans_mutex);
}

static int send_purge(struct dlm_ls *ls, int nodeid, int pid)
{
	struct dlm_message *ms;
	struct dlm_mhandle *mh;
	int error;

	error = _create_message(ls, sizeof(struct dlm_message), nodeid,
				DLM_MSG_PURGE, &ms, &mh);
	if (error)
		return error;
	ms->m_nodeid = nodeid;
	ms->m_pid = pid;

	return send_message(mh, ms);
}

int dlm_user_purge(struct dlm_ls *ls, struct dlm_user_proc *proc,
		   int nodeid, int pid)
{
	int error = 0;

	if (nodeid != dlm_our_nodeid()) {
		error = send_purge(ls, nodeid, pid);
	} else {
		dlm_lock_recovery(ls);
		if (pid == current->pid)
			purge_proc_locks(ls, proc);
		else
			do_purge(ls, nodeid, pid);
		dlm_unlock_recovery(ls);
	}
	return error;
}