summaryrefslogtreecommitdiffstats
path: root/sys/kern/vfs_subr.c
blob: b49717cf6114e872cd24dda822da3e80cbbe7f70 (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
/*
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
 * $FreeBSD$
 */

/*
 * External virtual filesystem routines
 */
#include "opt_ddb.h"
#include "opt_ffs.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_zone.h>

static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");

static void	addalias __P((struct vnode *vp, dev_t nvp_rdev));
static void	insmntque __P((struct vnode *vp, struct mount *mp));
static void	vclean __P((struct vnode *vp, int flags, struct thread *td));
static void	vlruvp(struct vnode *vp);

/*
 * Number of vnodes in existence.  Increased whenever getnewvnode()
 * allocates a new vnode, never decreased.
 */
static unsigned long	numvnodes;

SYSCTL_LONG(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");

/*
 * Conversion tables for conversion from vnode types to inode formats
 * and back.
 */
enum vtype iftovt_tab[16] = {
	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
};
int vttoif_tab[9] = {
	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
	S_IFSOCK, S_IFIFO, S_IFMT,
};

/*
 * List of vnodes that are ready for recycling.
 */
static TAILQ_HEAD(freelst, vnode) vnode_free_list;

/*
 * Minimum number of free vnodes.  If there are fewer than this free vnodes,
 * getnewvnode() will return a newly allocated vnode.
 */
static u_long wantfreevnodes = 25;
SYSCTL_LONG(_debug, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
/* Number of vnodes in the free list. */
static u_long freevnodes;
SYSCTL_LONG(_debug, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");

#if 0
/* Number of vnode allocation. */
static u_long vnodeallocs;
SYSCTL_LONG(_debug, OID_AUTO, vnodeallocs, CTLFLAG_RD, &vnodeallocs, 0, "");
/* Period of vnode recycle from namecache in vnode allocation times. */
static u_long vnoderecycleperiod = 1000;
SYSCTL_LONG(_debug, OID_AUTO, vnoderecycleperiod, CTLFLAG_RW, &vnoderecycleperiod, 0, "");
/* Minimum number of total vnodes required to invoke vnode recycle from namecache. */
static u_long vnoderecyclemintotalvn = 2000;
SYSCTL_LONG(_debug, OID_AUTO, vnoderecyclemintotalvn, CTLFLAG_RW, &vnoderecyclemintotalvn, 0, "");
/* Minimum number of free vnodes required to invoke vnode recycle from namecache. */
static u_long vnoderecycleminfreevn = 2000;
SYSCTL_LONG(_debug, OID_AUTO, vnoderecycleminfreevn, CTLFLAG_RW, &vnoderecycleminfreevn, 0, "");
/* Number of vnodes attempted to recycle at a time. */
static u_long vnoderecyclenumber = 3000;
SYSCTL_LONG(_debug, OID_AUTO, vnoderecyclenumber, CTLFLAG_RW, &vnoderecyclenumber, 0, "");
#endif

/*
 * Various variables used for debugging the new implementation of
 * reassignbuf().
 * XXX these are probably of (very) limited utility now.
 */
static int reassignbufcalls;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
static int reassignbufloops;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW, &reassignbufloops, 0, "");
static int reassignbufsortgood;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW, &reassignbufsortgood, 0, "");
static int reassignbufsortbad;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW, &reassignbufsortbad, 0, "");
/* Set to 0 for old insertion-sort based reassignbuf, 1 for modern method. */
static int reassignbufmethod = 1;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW, &reassignbufmethod, 0, "");
static int nameileafonly;
SYSCTL_INT(_vfs, OID_AUTO, nameileafonly, CTLFLAG_RW, &nameileafonly, 0, "");

#ifdef ENABLE_VFS_IOOPT
/* See NOTES for a description of this setting. */
int vfs_ioopt;
SYSCTL_INT(_vfs, OID_AUTO, ioopt, CTLFLAG_RW, &vfs_ioopt, 0, "");
#endif

/* List of mounted filesystems. */
struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);

/* For any iteration/modification of mountlist */
struct mtx mountlist_mtx;

/* For any iteration/modification of mnt_vnodelist */
struct mtx mntvnode_mtx;

/*
 * Cache for the mount type id assigned to NFS.  This is used for
 * special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
 */
int	nfs_mount_type = -1;

/* To keep more than one thread at a time from running vfs_getnewfsid */
static struct mtx mntid_mtx;

/* For any iteration/modification of vnode_free_list */
static struct mtx vnode_free_list_mtx;

/*
 * For any iteration/modification of dev->si_hlist (linked through
 * v_specnext)
 */
static struct mtx spechash_mtx;

/* Publicly exported FS */
struct nfs_public nfs_pub;

/* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
static vm_zone_t vnode_zone;
static vm_zone_t vnodepoll_zone;

/* Set to 1 to print out reclaim of active vnodes */
int	prtactive;

/*
 * The workitem queue.
 * 
 * It is useful to delay writes of file data and filesystem metadata
 * for tens of seconds so that quickly created and deleted files need
 * not waste disk bandwidth being created and removed. To realize this,
 * we append vnodes to a "workitem" queue. When running with a soft
 * updates implementation, most pending metadata dependencies should
 * not wait for more than a few seconds. Thus, mounted on block devices
 * are delayed only about a half the time that file data is delayed.
 * Similarly, directory updates are more critical, so are only delayed
 * about a third the time that file data is delayed. Thus, there are
 * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
 * one each second (driven off the filesystem syncer process). The
 * syncer_delayno variable indicates the next queue that is to be processed.
 * Items that need to be processed soon are placed in this queue:
 *
 *	syncer_workitem_pending[syncer_delayno]
 *
 * A delay of fifteen seconds is done by placing the request fifteen
 * entries later in the queue:
 *
 *	syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
 *
 */
static int syncer_delayno;
static long syncer_mask; 
LIST_HEAD(synclist, vnode);
static struct synclist *syncer_workitem_pending;

#define SYNCER_MAXDELAY		32
static int syncer_maxdelay = SYNCER_MAXDELAY;	/* maximum delay time */
static int syncdelay = 30;		/* max time to delay syncing data */
static int filedelay = 30;		/* time to delay syncing files */
SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
static int dirdelay = 29;		/* time to delay syncing directories */
SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
static int metadelay = 28;		/* time to delay syncing metadata */
SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
static int rushjob;		/* number of slots to run ASAP */
static int stat_rush_requests;	/* number of times I/O speeded up */
SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "");

/*
 * Number of vnodes we want to exist at any one time.  This is mostly used
 * to size hash tables in vnode-related code.  It is normally not used in
 * getnewvnode(), as wantfreevnodes is normally nonzero.)
 *
 * XXX desiredvnodes is historical cruft and should not exist.
 */
int desiredvnodes;
SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW, 
    &desiredvnodes, 0, "Maximum number of vnodes");
static int minvnodes; 
SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
    &minvnodes, 0, "Minimum number of vnodes");
static int vnlru_nowhere;
SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW, &vnlru_nowhere, 0,
    "Number of times the vnlru process ran without success");

void
v_addpollinfo(struct vnode *vp)
{
	vp->v_pollinfo = zalloc(vnodepoll_zone);
	mtx_init(&vp->v_pollinfo->vpi_lock, "vnode pollinfo", MTX_DEF);
}

/*
 * Initialize the vnode management data structures.
 */
static void
vntblinit(void *dummy __unused)
{

	desiredvnodes = maxproc + cnt.v_page_count / 4;
	minvnodes = desiredvnodes / 4;
	mtx_init(&mountlist_mtx, "mountlist", MTX_DEF);
	mtx_init(&mntvnode_mtx, "mntvnode", MTX_DEF);
	mtx_init(&mntid_mtx, "mntid", MTX_DEF);
	mtx_init(&spechash_mtx, "spechash", MTX_DEF);
	TAILQ_INIT(&vnode_free_list);
	mtx_init(&vnode_free_list_mtx, "vnode_free_list", MTX_DEF);
	vnode_zone = zinit("VNODE", sizeof (struct vnode), 0, 0, 5);
	vnodepoll_zone = zinit("VNODEPOLL", sizeof (struct vpollinfo), 0, 0, 5);
	/*
	 * Initialize the filesystem syncer.
	 */     
	syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE, 
		&syncer_mask);
	syncer_maxdelay = syncer_mask + 1;
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL)


/*
 * Mark a mount point as busy. Used to synchronize access and to delay
 * unmounting. Interlock is not released on failure.
 */
int
vfs_busy(mp, flags, interlkp, td)
	struct mount *mp;
	int flags;
	struct mtx *interlkp;
	struct thread *td;
{
	int lkflags;

	if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
		if (flags & LK_NOWAIT)
			return (ENOENT);
		mp->mnt_kern_flag |= MNTK_MWAIT;
		/*
		 * Since all busy locks are shared except the exclusive
		 * lock granted when unmounting, the only place that a
		 * wakeup needs to be done is at the release of the
		 * exclusive lock at the end of dounmount.
		 */
		msleep((caddr_t)mp, interlkp, PVFS, "vfs_busy", 0);
		return (ENOENT);
	}
	lkflags = LK_SHARED | LK_NOPAUSE;
	if (interlkp)
		lkflags |= LK_INTERLOCK;
	if (lockmgr(&mp->mnt_lock, lkflags, interlkp, td))
		panic("vfs_busy: unexpected lock failure");
	return (0);
}

/*
 * Free a busy filesystem.
 */
void
vfs_unbusy(mp, td)
	struct mount *mp;
	struct thread *td;
{

	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
}

/*
 * Lookup a filesystem type, and if found allocate and initialize
 * a mount structure for it.
 *
 * Devname is usually updated by mount(8) after booting.
 */
int
vfs_rootmountalloc(fstypename, devname, mpp)
	char *fstypename;
	char *devname;
	struct mount **mpp;
{
	struct thread *td = curthread;	/* XXX */
	struct vfsconf *vfsp;
	struct mount *mp;

	if (fstypename == NULL)
		return (ENODEV);
	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
		if (!strcmp(vfsp->vfc_name, fstypename))
			break;
	if (vfsp == NULL)
		return (ENODEV);
	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO);
	lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, LK_NOPAUSE);
	(void)vfs_busy(mp, LK_NOWAIT, 0, td);
	TAILQ_INIT(&mp->mnt_nvnodelist);
	TAILQ_INIT(&mp->mnt_reservedvnlist);
	mp->mnt_vfc = vfsp;
	mp->mnt_op = vfsp->vfc_vfsops;
	mp->mnt_flag = MNT_RDONLY;
	mp->mnt_vnodecovered = NULLVP;
	vfsp->vfc_refcount++;
	mp->mnt_iosize_max = DFLTPHYS;
	mp->mnt_stat.f_type = vfsp->vfc_typenum;
	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
	mp->mnt_stat.f_mntonname[0] = '/';
	mp->mnt_stat.f_mntonname[1] = 0;
	(void) copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);
	*mpp = mp;
	return (0);
}

/*
 * Find an appropriate filesystem to use for the root. If a filesystem
 * has not been preselected, walk through the list of known filesystems
 * trying those that have mountroot routines, and try them until one
 * works or we have tried them all.
 */
#ifdef notdef	/* XXX JH */
int
lite2_vfs_mountroot()
{
	struct vfsconf *vfsp;
	extern int (*lite2_mountroot) __P((void));
	int error;

	if (lite2_mountroot != NULL)
		return ((*lite2_mountroot)());
	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		if (vfsp->vfc_mountroot == NULL)
			continue;
		if ((error = (*vfsp->vfc_mountroot)()) == 0)
			return (0);
		printf("%s_mountroot failed: %d\n", vfsp->vfc_name, error);
	}
	return (ENODEV);
}
#endif

/*
 * Lookup a mount point by filesystem identifier.
 */
struct mount *
vfs_getvfs(fsid)
	fsid_t *fsid;
{
	register struct mount *mp;

	mtx_lock(&mountlist_mtx);
	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
		if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
		    mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
			mtx_unlock(&mountlist_mtx);
			return (mp);
	    }
	}
	mtx_unlock(&mountlist_mtx);
	return ((struct mount *) 0);
}

/*
 * Get a new unique fsid.  Try to make its val[0] unique, since this value
 * will be used to create fake device numbers for stat().  Also try (but
 * not so hard) make its val[0] unique mod 2^16, since some emulators only
 * support 16-bit device numbers.  We end up with unique val[0]'s for the
 * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
 *
 * Keep in mind that several mounts may be running in parallel.  Starting
 * the search one past where the previous search terminated is both a
 * micro-optimization and a defense against returning the same fsid to
 * different mounts.
 */
void
vfs_getnewfsid(mp)
	struct mount *mp;
{
	static u_int16_t mntid_base;
	fsid_t tfsid;
	int mtype;

	mtx_lock(&mntid_mtx);
	mtype = mp->mnt_vfc->vfc_typenum;
	tfsid.val[1] = mtype;
	mtype = (mtype & 0xFF) << 24;
	for (;;) {
		tfsid.val[0] = makeudev(255,
		    mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
		mntid_base++;
		if (vfs_getvfs(&tfsid) == NULL)
			break;
	}
	mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
	mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
	mtx_unlock(&mntid_mtx);
}

/*
 * Knob to control the precision of file timestamps:
 *
 *   0 = seconds only; nanoseconds zeroed.
 *   1 = seconds and nanoseconds, accurate within 1/HZ.
 *   2 = seconds and nanoseconds, truncated to microseconds.
 * >=3 = seconds and nanoseconds, maximum precision.
 */
enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };

static int timestamp_precision = TSP_SEC;
SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
    &timestamp_precision, 0, "");

/*
 * Get a current timestamp.
 */
void
vfs_timestamp(tsp)
	struct timespec *tsp;
{
	struct timeval tv;

	switch (timestamp_precision) {
	case TSP_SEC:
		tsp->tv_sec = time_second;
		tsp->tv_nsec = 0;
		break;
	case TSP_HZ:
		getnanotime(tsp);
		break;
	case TSP_USEC:
		microtime(&tv);
		TIMEVAL_TO_TIMESPEC(&tv, tsp);
		break;
	case TSP_NSEC:
	default:
		nanotime(tsp);
		break;
	}
}

/*
 * Set vnode attributes to VNOVAL
 */
void
vattr_null(vap)
	register struct vattr *vap;
{

	vap->va_type = VNON;
	vap->va_size = VNOVAL;
	vap->va_bytes = VNOVAL;
	vap->va_mode = VNOVAL;
	vap->va_nlink = VNOVAL;
	vap->va_uid = VNOVAL;
	vap->va_gid = VNOVAL;
	vap->va_fsid = VNOVAL;
	vap->va_fileid = VNOVAL;
	vap->va_blocksize = VNOVAL;
	vap->va_rdev = VNOVAL;
	vap->va_atime.tv_sec = VNOVAL;
	vap->va_atime.tv_nsec = VNOVAL;
	vap->va_mtime.tv_sec = VNOVAL;
	vap->va_mtime.tv_nsec = VNOVAL;
	vap->va_ctime.tv_sec = VNOVAL;
	vap->va_ctime.tv_nsec = VNOVAL;
	vap->va_flags = VNOVAL;
	vap->va_gen = VNOVAL;
	vap->va_vaflags = 0;
}

/*
 * This routine is called when we have too many vnodes.  It attempts
 * to free <count> vnodes and will potentially free vnodes that still
 * have VM backing store (VM backing store is typically the cause
 * of a vnode blowout so we want to do this).  Therefore, this operation
 * is not considered cheap.
 *
 * A number of conditions may prevent a vnode from being reclaimed.
 * the buffer cache may have references on the vnode, a directory
 * vnode may still have references due to the namei cache representing
 * underlying files, or the vnode may be in active use.   It is not
 * desireable to reuse such vnodes.  These conditions may cause the
 * number of vnodes to reach some minimum value regardless of what
 * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
 */
static int
vlrureclaim(struct mount *mp, int count)
{
	struct vnode *vp;
	int done;
	int trigger;
	int usevnodes;

	/*
	 * Calculate the trigger point, don't allow user
	 * screwups to blow us up.   This prevents us from
	 * recycling vnodes with lots of resident pages.  We
	 * aren't trying to free memory, we are trying to
	 * free vnodes.
	 */
	usevnodes = desiredvnodes;
	if (usevnodes <= 0)
		usevnodes = 1;
	trigger = cnt.v_page_count * 2 / usevnodes;

	done = 0;
	mtx_lock(&mntvnode_mtx);
	while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) {
		TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
		TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);

		if (vp->v_type != VNON &&
		    vp->v_type != VBAD &&
		    VMIGHTFREE(vp) &&           /* critical path opt */
		    (vp->v_object == NULL || vp->v_object->resident_page_count < trigger) &&
		    mtx_trylock(&vp->v_interlock)
		) {
			mtx_unlock(&mntvnode_mtx);
			if (VMIGHTFREE(vp)) {
				vgonel(vp, curthread);
				done++;
			} else {
				mtx_unlock(&vp->v_interlock);
			}
			mtx_lock(&mntvnode_mtx);
		}
		--count;
	}
	mtx_unlock(&mntvnode_mtx);
	return done;
}

/*
 * Attempt to recycle vnodes in a context that is always safe to block.
 * Calling vlrurecycle() from the bowels of file system code has some
 * interesting deadlock problems.
 */
static struct proc *vnlruproc;
static int vnlruproc_sig;

static void 
vnlru_proc(void)
{
	struct mount *mp, *nmp;
	int s;
	int done;
	struct proc *p = vnlruproc;
	struct thread *td = FIRST_THREAD_IN_PROC(p);	/* XXXKSE */

	mtx_lock(&Giant);

	EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
	    SHUTDOWN_PRI_FIRST);   

	s = splbio();
	for (;;) {
		kthread_suspend_check(p);
		if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) {
			vnlruproc_sig = 0;
			tsleep(vnlruproc, PVFS, "vlruwt", 0);
			continue;
		}
		done = 0;
		mtx_lock(&mountlist_mtx);
		for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
			if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
				nmp = TAILQ_NEXT(mp, mnt_list);
				continue;
			}
			done += vlrureclaim(mp, 10);
			mtx_lock(&mountlist_mtx);
			nmp = TAILQ_NEXT(mp, mnt_list);
			vfs_unbusy(mp, td);
		}
		mtx_unlock(&mountlist_mtx);
		if (done == 0) {
#if 0
			/* These messages are temporary debugging aids */
			if (vnlru_nowhere < 5)
				printf("vnlru process getting nowhere..\n");
			else if (vnlru_nowhere == 5)
				printf("vnlru process messages stopped.\n");
#endif
			vnlru_nowhere++;
			tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
		}
	}
	splx(s);
}

static struct kproc_desc vnlru_kp = {
	"vnlru",
	vnlru_proc,
	&vnlruproc
};
SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp)


/*
 * Routines having to do with the management of the vnode table.
 */

/*
 * Return the next vnode from the free list.
 */
int
getnewvnode(tag, mp, vops, vpp)
	enum vtagtype tag;
	struct mount *mp;
	vop_t **vops;
	struct vnode **vpp;
{
	int s;
	struct thread *td = curthread;	/* XXX */
	struct vnode *vp = NULL;
	struct mount *vnmp;
	vm_object_t object;

	s = splbio();
	/*
	 * Try to reuse vnodes if we hit the max.  This situation only
	 * occurs in certain large-memory (2G+) situations.  We cannot
	 * attempt to directly reclaim vnodes due to nasty recursion
	 * problems.
	 */
	if (vnlruproc_sig == 0 && numvnodes - freevnodes > desiredvnodes) {
		vnlruproc_sig = 1;      /* avoid unnecessary wakeups */
		wakeup(vnlruproc);
	}

	/*
	 * Attempt to reuse a vnode already on the free list, allocating
	 * a new vnode if we can't find one or if we have not reached a
	 * good minimum for good LRU performance.
	 */

	mtx_lock(&vnode_free_list_mtx);

	if (freevnodes >= wantfreevnodes && numvnodes >= minvnodes) {
		int count;

		for (count = 0; count < freevnodes; count++) {
			vp = TAILQ_FIRST(&vnode_free_list);
			if (vp == NULL || vp->v_usecount)
				panic("getnewvnode: free vnode isn't");
			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);

			/*
			 * Don't recycle if we still have cached pages or if
			 * we cannot get the interlock.
			 */
			if ((VOP_GETVOBJECT(vp, &object) == 0 &&
			     (object->resident_page_count ||
			      object->ref_count)) ||
			     !mtx_trylock(&vp->v_interlock)) {
				TAILQ_INSERT_TAIL(&vnode_free_list, vp,
						    v_freelist);
				vp = NULL;
				continue;
			}
			if (LIST_FIRST(&vp->v_cache_src)) {
				/*
				 * note: nameileafonly sysctl is temporary,
				 * for debugging only, and will eventually be
				 * removed.
				 */
				if (nameileafonly > 0) {
					/*
					 * Do not reuse namei-cached directory
					 * vnodes that have cached
					 * subdirectories.
					 */
					if (cache_leaf_test(vp) < 0) {
						mtx_unlock(&vp->v_interlock);
						TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
						vp = NULL;
						continue;
					}
				} else if (nameileafonly < 0 ||
					    vmiodirenable == 0) {
					/*
					 * Do not reuse namei-cached directory
					 * vnodes if nameileafonly is -1 or
					 * if VMIO backing for directories is
					 * turned off (otherwise we reuse them
					 * too quickly).
					 */
					mtx_unlock(&vp->v_interlock);
					TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
					vp = NULL;
					continue;
				}
			}
			/*
			 * Skip over it if its filesystem is being suspended.
			 */
			if (vn_start_write(vp, &vnmp, V_NOWAIT) == 0)
				break;
			mtx_unlock(&vp->v_interlock);
			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
			vp = NULL;
		}
	}
	if (vp) {
		vp->v_flag |= VDOOMED;
		vp->v_flag &= ~VFREE;
		freevnodes--;
		mtx_unlock(&vnode_free_list_mtx);
		cache_purge(vp);
		if (vp->v_type != VBAD) {
			vgonel(vp, td);
		} else {
			mtx_unlock(&vp->v_interlock);
		}
		vn_finished_write(vnmp);

#ifdef INVARIANTS
		{
			int s;

			if (vp->v_data)
				panic("cleaned vnode isn't");
			s = splbio();
			if (vp->v_numoutput)
				panic("Clean vnode has pending I/O's");
			splx(s);
			if (vp->v_writecount != 0)
				panic("Non-zero write count");
		}
#endif
		if (vp->v_pollinfo) {
			mtx_destroy(&vp->v_pollinfo->vpi_lock);
			zfree(vnodepoll_zone, vp->v_pollinfo);
		}
		vp->v_pollinfo = NULL;
		vp->v_flag = 0;
		vp->v_lastw = 0;
		vp->v_lasta = 0;
		vp->v_cstart = 0;
		vp->v_clen = 0;
		vp->v_socket = 0;
	} else {
		mtx_unlock(&vnode_free_list_mtx);
		vp = (struct vnode *) zalloc(vnode_zone);
		bzero((char *) vp, sizeof *vp);
		mtx_init(&vp->v_interlock, "vnode interlock", MTX_DEF);
		vp->v_dd = vp;
		cache_purge(vp);
		LIST_INIT(&vp->v_cache_src);
		TAILQ_INIT(&vp->v_cache_dst);
		numvnodes++;
	}

	TAILQ_INIT(&vp->v_cleanblkhd);
	TAILQ_INIT(&vp->v_dirtyblkhd);
	vp->v_type = VNON;
	vp->v_tag = tag;
	vp->v_op = vops;
	lockinit(&vp->v_lock, PVFS, "vnlock", VLKTIMEOUT, LK_NOPAUSE);
	insmntque(vp, mp);
	*vpp = vp;
	vp->v_usecount = 1;
	vp->v_data = 0;

	splx(s);

	vfs_object_create(vp, td, td->td_proc->p_ucred);

#if 0
	vnodeallocs++;
	if (vnodeallocs % vnoderecycleperiod == 0 &&
	    freevnodes < vnoderecycleminfreevn &&
	    vnoderecyclemintotalvn < numvnodes) {
		/* Recycle vnodes. */
		cache_purgeleafdirs(vnoderecyclenumber);
	}
#endif

	return (0);
}

/*
 * Move a vnode from one mount queue to another.
 */
static void
insmntque(vp, mp)
	register struct vnode *vp;
	register struct mount *mp;
{

	mtx_lock(&mntvnode_mtx);
	/*
	 * Delete from old mount point vnode list, if on one.
	 */
	if (vp->v_mount != NULL)
		TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
	/*
	 * Insert into list of vnodes for the new mount point, if available.
	 */
	if ((vp->v_mount = mp) == NULL) {
		mtx_unlock(&mntvnode_mtx);
		return;
	}
	TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
	mtx_unlock(&mntvnode_mtx);
}

/*
 * Update outstanding I/O count and do wakeup if requested.
 */
void
vwakeup(bp)
	register struct buf *bp;
{
	register struct vnode *vp;

	bp->b_flags &= ~B_WRITEINPROG;
	if ((vp = bp->b_vp)) {
		vp->v_numoutput--;
		if (vp->v_numoutput < 0)
			panic("vwakeup: neg numoutput");
		if ((vp->v_numoutput == 0) && (vp->v_flag & VBWAIT)) {
			vp->v_flag &= ~VBWAIT;
			wakeup((caddr_t) &vp->v_numoutput);
		}
	}
}

/*
 * Flush out and invalidate all buffers associated with a vnode.
 * Called with the underlying object locked.
 */
int
vinvalbuf(vp, flags, cred, td, slpflag, slptimeo)
	register struct vnode *vp;
	int flags;
	struct ucred *cred;
	struct thread *td;
	int slpflag, slptimeo;
{
	register struct buf *bp;
	struct buf *nbp, *blist;
	int s, error;
	vm_object_t object;

	GIANT_REQUIRED;

	if (flags & V_SAVE) {
		s = splbio();
		while (vp->v_numoutput) {
			vp->v_flag |= VBWAIT;
			error = tsleep((caddr_t)&vp->v_numoutput,
			    slpflag | (PRIBIO + 1), "vinvlbuf", slptimeo);
			if (error) {
				splx(s);
				return (error);
			}
		}
		if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
			splx(s);
			if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, td)) != 0)
				return (error);
			s = splbio();
			if (vp->v_numoutput > 0 ||
			    !TAILQ_EMPTY(&vp->v_dirtyblkhd))
				panic("vinvalbuf: dirty bufs");
		}
		splx(s);
  	}
	s = splbio();
	for (;;) {
		blist = TAILQ_FIRST(&vp->v_cleanblkhd);
		if (!blist)
			blist = TAILQ_FIRST(&vp->v_dirtyblkhd);
		if (!blist)
			break;

		for (bp = blist; bp; bp = nbp) {
			nbp = TAILQ_NEXT(bp, b_vnbufs);
			if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
				error = BUF_TIMELOCK(bp,
				    LK_EXCLUSIVE | LK_SLEEPFAIL,
				    "vinvalbuf", slpflag, slptimeo);
				if (error == ENOLCK)
					break;
				splx(s);
				return (error);
			}
			/*
			 * XXX Since there are no node locks for NFS, I
			 * believe there is a slight chance that a delayed
			 * write will occur while sleeping just above, so
			 * check for it.  Note that vfs_bio_awrite expects
			 * buffers to reside on a queue, while BUF_WRITE and
			 * brelse do not.
			 */
			if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
				(flags & V_SAVE)) {

				if (bp->b_vp == vp) {
					if (bp->b_flags & B_CLUSTEROK) {
						BUF_UNLOCK(bp);
						vfs_bio_awrite(bp);
					} else {
						bremfree(bp);
						bp->b_flags |= B_ASYNC;
						BUF_WRITE(bp);
					}
				} else {
					bremfree(bp);
					(void) BUF_WRITE(bp);
				}
				break;
			}
			bremfree(bp);
			bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
			bp->b_flags &= ~B_ASYNC;
			brelse(bp);
		}
	}

	/*
	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
	 * have write I/O in-progress but if there is a VM object then the
	 * VM object can also have read-I/O in-progress.
	 */
	do {
		while (vp->v_numoutput > 0) {
			vp->v_flag |= VBWAIT;
			tsleep(&vp->v_numoutput, PVM, "vnvlbv", 0);
		}
		if (VOP_GETVOBJECT(vp, &object) == 0) {
			while (object->paging_in_progress)
			vm_object_pip_sleep(object, "vnvlbx");
		}
	} while (vp->v_numoutput > 0);

	splx(s);

	/*
	 * Destroy the copy in the VM cache, too.
	 */
	mtx_lock(&vp->v_interlock);
	if (VOP_GETVOBJECT(vp, &object) == 0) {
		vm_object_page_remove(object, 0, 0,
			(flags & V_SAVE) ? TRUE : FALSE);
	}
	mtx_unlock(&vp->v_interlock);

	if (!TAILQ_EMPTY(&vp->v_dirtyblkhd) || !TAILQ_EMPTY(&vp->v_cleanblkhd))
		panic("vinvalbuf: flush failed");
	return (0);
}

/*
 * Truncate a file's buffer and pages to a specified length.  This
 * is in lieu of the old vinvalbuf mechanism, which performed unneeded
 * sync activity.
 */
int
vtruncbuf(vp, cred, td, length, blksize)
	register struct vnode *vp;
	struct ucred *cred;
	struct thread *td;
	off_t length;
	int blksize;
{
	register struct buf *bp;
	struct buf *nbp;
	int s, anyfreed;
	int trunclbn;

	/*
	 * Round up to the *next* lbn.
	 */
	trunclbn = (length + blksize - 1) / blksize;

	s = splbio();
restart:
	anyfreed = 1;
	for (;anyfreed;) {
		anyfreed = 0;
		for (bp = TAILQ_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
			nbp = TAILQ_NEXT(bp, b_vnbufs);
			if (bp->b_lblkno >= trunclbn) {
				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
					goto restart;
				} else {
					bremfree(bp);
					bp->b_flags |= (B_INVAL | B_RELBUF);
					bp->b_flags &= ~B_ASYNC;
					brelse(bp);
					anyfreed = 1;
				}
				if (nbp &&
				    (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
				    (nbp->b_vp != vp) ||
				    (nbp->b_flags & B_DELWRI))) {
					goto restart;
				}
			}
		}

		for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
			nbp = TAILQ_NEXT(bp, b_vnbufs);
			if (bp->b_lblkno >= trunclbn) {
				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
					goto restart;
				} else {
					bremfree(bp);
					bp->b_flags |= (B_INVAL | B_RELBUF);
					bp->b_flags &= ~B_ASYNC;
					brelse(bp);
					anyfreed = 1;
				}
				if (nbp &&
				    (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
				    (nbp->b_vp != vp) ||
				    (nbp->b_flags & B_DELWRI) == 0)) {
					goto restart;
				}
			}
		}
	}

	if (length > 0) {
restartsync:
		for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
			nbp = TAILQ_NEXT(bp, b_vnbufs);
			if ((bp->b_flags & B_DELWRI) && (bp->b_lblkno < 0)) {
				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
					goto restart;
				} else {
					bremfree(bp);
					if (bp->b_vp == vp) {
						bp->b_flags |= B_ASYNC;
					} else {
						bp->b_flags &= ~B_ASYNC;
					}
					BUF_WRITE(bp);
				}
				goto restartsync;
			}

		}
	}

	while (vp->v_numoutput > 0) {
		vp->v_flag |= VBWAIT;
		tsleep(&vp->v_numoutput, PVM, "vbtrunc", 0);
	}

	splx(s);

	vnode_pager_setsize(vp, length);

	return (0);
}

/*
 * Associate a buffer with a vnode.
 */
void
bgetvp(vp, bp)
	register struct vnode *vp;
	register struct buf *bp;
{
	int s;

	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));

	vhold(vp);
	bp->b_vp = vp;
	bp->b_dev = vn_todev(vp);
	/*
	 * Insert onto list for new vnode.
	 */
	s = splbio();
	bp->b_xflags |= BX_VNCLEAN;
	bp->b_xflags &= ~BX_VNDIRTY;
	TAILQ_INSERT_TAIL(&vp->v_cleanblkhd, bp, b_vnbufs);
	splx(s);
}

/*
 * Disassociate a buffer from a vnode.
 */
void
brelvp(bp)
	register struct buf *bp;
{
	struct vnode *vp;
	struct buflists *listheadp;
	int s;

	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));

	/*
	 * Delete from old vnode list, if on one.
	 */
	vp = bp->b_vp;
	s = splbio();
	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
		if (bp->b_xflags & BX_VNDIRTY)
			listheadp = &vp->v_dirtyblkhd;
		else 
			listheadp = &vp->v_cleanblkhd;
		TAILQ_REMOVE(listheadp, bp, b_vnbufs);
		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
	}
	if ((vp->v_flag & VONWORKLST) && TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
		vp->v_flag &= ~VONWORKLST;
		LIST_REMOVE(vp, v_synclist);
	}
	splx(s);
	bp->b_vp = (struct vnode *) 0;
	vdrop(vp);
}

/*
 * Add an item to the syncer work queue.
 */
static void
vn_syncer_add_to_worklist(struct vnode *vp, int delay)
{
	int s, slot;

	s = splbio();

	if (vp->v_flag & VONWORKLST) {
		LIST_REMOVE(vp, v_synclist);
	}

	if (delay > syncer_maxdelay - 2)
		delay = syncer_maxdelay - 2;
	slot = (syncer_delayno + delay) & syncer_mask;

	LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
	vp->v_flag |= VONWORKLST;
	splx(s);
}

struct  proc *updateproc;
static void sched_sync __P((void));
static struct kproc_desc up_kp = {
	"syncer",
	sched_sync,
	&updateproc
};
SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)

/*
 * System filesystem synchronizer daemon.
 */
void 
sched_sync(void)
{
	struct synclist *slp;
	struct vnode *vp;
	struct mount *mp;
	long starttime;
	int s;
	struct thread *td = FIRST_THREAD_IN_PROC(updateproc);  /* XXXKSE */

	mtx_lock(&Giant);

	EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, td->td_proc,
	    SHUTDOWN_PRI_LAST);   

	for (;;) {
		kthread_suspend_check(td->td_proc);

		starttime = time_second;

		/*
		 * Push files whose dirty time has expired.  Be careful
		 * of interrupt race on slp queue.
		 */
		s = splbio();
		slp = &syncer_workitem_pending[syncer_delayno];
		syncer_delayno += 1;
		if (syncer_delayno == syncer_maxdelay)
			syncer_delayno = 0;
		splx(s);

		while ((vp = LIST_FIRST(slp)) != NULL) {
			if (VOP_ISLOCKED(vp, NULL) == 0 &&
			    vn_start_write(vp, &mp, V_NOWAIT) == 0) {
				vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
				(void) VOP_FSYNC(vp, td->td_proc->p_ucred, MNT_LAZY, td);
				VOP_UNLOCK(vp, 0, td);
				vn_finished_write(mp);
			}
			s = splbio();
			if (LIST_FIRST(slp) == vp) {
				/*
				 * Note: v_tag VT_VFS vps can remain on the
				 * worklist too with no dirty blocks, but 
				 * since sync_fsync() moves it to a different 
				 * slot we are safe.
				 */
				if (TAILQ_EMPTY(&vp->v_dirtyblkhd) &&
				    !vn_isdisk(vp, NULL))
					panic("sched_sync: fsync failed vp %p tag %d", vp, vp->v_tag);
				/*
				 * Put us back on the worklist.  The worklist
				 * routine will remove us from our current
				 * position and then add us back in at a later
				 * position.
				 */
				vn_syncer_add_to_worklist(vp, syncdelay);
			}
			splx(s);
		}

		/*
		 * Do soft update processing.
		 */
#ifdef SOFTUPDATES
		softdep_process_worklist(NULL);
#endif

		/*
		 * The variable rushjob allows the kernel to speed up the
		 * processing of the filesystem syncer process. A rushjob
		 * value of N tells the filesystem syncer to process the next
		 * N seconds worth of work on its queue ASAP. Currently rushjob
		 * is used by the soft update code to speed up the filesystem
		 * syncer process when the incore state is getting so far
		 * ahead of the disk that the kernel memory pool is being
		 * threatened with exhaustion.
		 */
		if (rushjob > 0) {
			rushjob -= 1;
			continue;
		}
		/*
		 * If it has taken us less than a second to process the
		 * current work, then wait. Otherwise start right over
		 * again. We can still lose time if any single round
		 * takes more than two seconds, but it does not really
		 * matter as we are just trying to generally pace the
		 * filesystem activity.
		 */
		if (time_second == starttime)
			tsleep(&lbolt, PPAUSE, "syncer", 0);
	}
}

/*
 * Request the syncer daemon to speed up its work.
 * We never push it to speed up more than half of its
 * normal turn time, otherwise it could take over the cpu.
 * XXXKSE  only one update?
 */
int
speedup_syncer()
{

	mtx_lock_spin(&sched_lock);
	if (FIRST_THREAD_IN_PROC(updateproc)->td_wchan == &lbolt) /* XXXKSE */
		setrunnable(FIRST_THREAD_IN_PROC(updateproc));
	mtx_unlock_spin(&sched_lock);
	if (rushjob < syncdelay / 2) {
		rushjob += 1;
		stat_rush_requests += 1;
		return (1);
	}
	return(0);
}

/*
 * Associate a p-buffer with a vnode.
 *
 * Also sets B_PAGING flag to indicate that vnode is not fully associated
 * with the buffer.  i.e. the bp has not been linked into the vnode or
 * ref-counted.
 */
void
pbgetvp(vp, bp)
	register struct vnode *vp;
	register struct buf *bp;
{

	KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));

	bp->b_vp = vp;
	bp->b_flags |= B_PAGING;
	bp->b_dev = vn_todev(vp);
}

/*
 * Disassociate a p-buffer from a vnode.
 */
void
pbrelvp(bp)
	register struct buf *bp;
{

	KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));

	/* XXX REMOVE ME */
	if (TAILQ_NEXT(bp, b_vnbufs) != NULL) {
		panic(
		    "relpbuf(): b_vp was probably reassignbuf()d %p %x", 
		    bp,
		    (int)bp->b_flags
		);
	}
	bp->b_vp = (struct vnode *) 0;
	bp->b_flags &= ~B_PAGING;
}

/*
 * Change the vnode a pager buffer is associated with.
 */
void
pbreassignbuf(bp, newvp)
	struct buf *bp;
	struct vnode *newvp;
{

	KASSERT(bp->b_flags & B_PAGING,
	    ("pbreassignbuf() on non phys bp %p", bp));
	bp->b_vp = newvp;
}

/*
 * Reassign a buffer from one vnode to another.
 * Used to assign file specific control information
 * (indirect blocks) to the vnode to which they belong.
 */
void
reassignbuf(bp, newvp)
	register struct buf *bp;
	register struct vnode *newvp;
{
	struct buflists *listheadp;
	int delay;
	int s;

	if (newvp == NULL) {
		printf("reassignbuf: NULL");
		return;
	}
	++reassignbufcalls;

	/*
	 * B_PAGING flagged buffers cannot be reassigned because their vp
	 * is not fully linked in.
	 */
	if (bp->b_flags & B_PAGING)
		panic("cannot reassign paging buffer");

	s = splbio();
	/*
	 * Delete from old vnode list, if on one.
	 */
	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
		if (bp->b_xflags & BX_VNDIRTY)
			listheadp = &bp->b_vp->v_dirtyblkhd;
		else 
			listheadp = &bp->b_vp->v_cleanblkhd;
		TAILQ_REMOVE(listheadp, bp, b_vnbufs);
		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
		if (bp->b_vp != newvp) {
			vdrop(bp->b_vp);
			bp->b_vp = NULL;	/* for clarification */
		}
	}
	/*
	 * If dirty, put on list of dirty buffers; otherwise insert onto list
	 * of clean buffers.
	 */
	if (bp->b_flags & B_DELWRI) {
		struct buf *tbp;

		listheadp = &newvp->v_dirtyblkhd;
		if ((newvp->v_flag & VONWORKLST) == 0) {
			switch (newvp->v_type) {
			case VDIR:
				delay = dirdelay;
				break;
			case VCHR:
				if (newvp->v_rdev->si_mountpoint != NULL) {
					delay = metadelay;
					break;
				}
				/* fall through */
			default:
				delay = filedelay;
			}
			vn_syncer_add_to_worklist(newvp, delay);
		}
		bp->b_xflags |= BX_VNDIRTY;
		tbp = TAILQ_FIRST(listheadp);
		if (tbp == NULL ||
		    bp->b_lblkno == 0 ||
		    (bp->b_lblkno > 0 && tbp->b_lblkno < 0) ||
		    (bp->b_lblkno > 0 && bp->b_lblkno < tbp->b_lblkno)) {
			TAILQ_INSERT_HEAD(listheadp, bp, b_vnbufs);
			++reassignbufsortgood;
		} else if (bp->b_lblkno < 0) {
			TAILQ_INSERT_TAIL(listheadp, bp, b_vnbufs);
			++reassignbufsortgood;
		} else if (reassignbufmethod == 1) {
			/*
			 * New sorting algorithm, only handle sequential case,
			 * otherwise append to end (but before metadata)
			 */
			if ((tbp = gbincore(newvp, bp->b_lblkno - 1)) != NULL &&
			    (tbp->b_xflags & BX_VNDIRTY)) {
				/*
				 * Found the best place to insert the buffer
				 */
				TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
				++reassignbufsortgood;
			} else {
				/*
				 * Missed, append to end, but before meta-data.
				 * We know that the head buffer in the list is
				 * not meta-data due to prior conditionals.
				 *
				 * Indirect effects:  NFS second stage write
				 * tends to wind up here, giving maximum 
				 * distance between the unstable write and the
				 * commit rpc.
				 */
				tbp = TAILQ_LAST(listheadp, buflists);
				while (tbp && tbp->b_lblkno < 0)
					tbp = TAILQ_PREV(tbp, buflists, b_vnbufs);
				TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
				++reassignbufsortbad;
			}
		} else {
			/*
			 * Old sorting algorithm, scan queue and insert
			 */
			struct buf *ttbp;
			while ((ttbp = TAILQ_NEXT(tbp, b_vnbufs)) &&
			    (ttbp->b_lblkno < bp->b_lblkno)) {
				++reassignbufloops;
				tbp = ttbp;
			}
			TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
		}
	} else {
		bp->b_xflags |= BX_VNCLEAN;
		TAILQ_INSERT_TAIL(&newvp->v_cleanblkhd, bp, b_vnbufs);
		if ((newvp->v_flag & VONWORKLST) &&
		    TAILQ_EMPTY(&newvp->v_dirtyblkhd)) {
			newvp->v_flag &= ~VONWORKLST;
			LIST_REMOVE(newvp, v_synclist);
		}
	}
	if (bp->b_vp != newvp) {
		bp->b_vp = newvp;
		vhold(bp->b_vp);
	}
	splx(s);
}

/*
 * Create a vnode for a device.
 * Used for mounting the root file system.
 */
int
bdevvp(dev, vpp)
	dev_t dev;
	struct vnode **vpp;
{
	register struct vnode *vp;
	struct vnode *nvp;
	int error;

	if (dev == NODEV) {
		*vpp = NULLVP;
		return (ENXIO);
	}
	if (vfinddev(dev, VCHR, vpp))
		return (0);
	error = getnewvnode(VT_NON, (struct mount *)0, spec_vnodeop_p, &nvp);
	if (error) {
		*vpp = NULLVP;
		return (error);
	}
	vp = nvp;
	vp->v_type = VCHR;
	addalias(vp, dev);
	*vpp = vp;
	return (0);
}

/*
 * Add vnode to the alias list hung off the dev_t.
 *
 * The reason for this gunk is that multiple vnodes can reference
 * the same physical device, so checking vp->v_usecount to see
 * how many users there are is inadequate; the v_usecount for
 * the vnodes need to be accumulated.  vcount() does that.
 */
struct vnode *
addaliasu(nvp, nvp_rdev)
	struct vnode *nvp;
	udev_t nvp_rdev;
{
	struct vnode *ovp;
	vop_t **ops;
	dev_t dev;

	if (nvp->v_type == VBLK)
		return (nvp);
	if (nvp->v_type != VCHR)
		panic("addaliasu on non-special vnode");
	dev = udev2dev(nvp_rdev, 0);
	/*
	 * Check to see if we have a bdevvp vnode with no associated
	 * filesystem. If so, we want to associate the filesystem of
	 * the new newly instigated vnode with the bdevvp vnode and
	 * discard the newly created vnode rather than leaving the
	 * bdevvp vnode lying around with no associated filesystem.
	 */
	if (vfinddev(dev, nvp->v_type, &ovp) == 0 || ovp->v_data != NULL) {
		addalias(nvp, dev);
		return (nvp);
	}
	/*
	 * Discard unneeded vnode, but save its node specific data.
	 * Note that if there is a lock, it is carried over in the
	 * node specific data to the replacement vnode.
	 */
	vref(ovp);
	ovp->v_data = nvp->v_data;
	ovp->v_tag = nvp->v_tag;
	nvp->v_data = NULL;
	lockinit(&ovp->v_lock, PVFS, nvp->v_lock.lk_wmesg,
	    nvp->v_lock.lk_timo, nvp->v_lock.lk_flags & LK_EXTFLG_MASK);
	if (nvp->v_vnlock)
		ovp->v_vnlock = &ovp->v_lock;
	ops = ovp->v_op;
	ovp->v_op = nvp->v_op;
	if (VOP_ISLOCKED(nvp, curthread)) {
		VOP_UNLOCK(nvp, 0, curthread);
		vn_lock(ovp, LK_EXCLUSIVE | LK_RETRY, curthread);
	}
	nvp->v_op = ops;
	insmntque(ovp, nvp->v_mount);
	vrele(nvp);
	vgone(nvp);
	return (ovp);
}

/* This is a local helper function that do the same as addaliasu, but for a
 * dev_t instead of an udev_t. */
static void
addalias(nvp, dev)
	struct vnode *nvp;
	dev_t dev;
{

	KASSERT(nvp->v_type == VCHR, ("addalias on non-special vnode"));
	nvp->v_rdev = dev;
	mtx_lock(&spechash_mtx);
	SLIST_INSERT_HEAD(&dev->si_hlist, nvp, v_specnext);
	mtx_unlock(&spechash_mtx);
}

/*
 * Grab a particular vnode from the free list, increment its
 * reference count and lock it. The vnode lock bit is set if the
 * vnode is being eliminated in vgone. The process is awakened
 * when the transition is completed, and an error returned to
 * indicate that the vnode is no longer usable (possibly having
 * been changed to a new file system type).
 */
int
vget(vp, flags, td)
	register struct vnode *vp;
	int flags;
	struct thread *td;
{
	int error;

	/*
	 * If the vnode is in the process of being cleaned out for
	 * another use, we wait for the cleaning to finish and then
	 * return failure. Cleaning is determined by checking that
	 * the VXLOCK flag is set.
	 */
	if ((flags & LK_INTERLOCK) == 0)
		mtx_lock(&vp->v_interlock);
	if (vp->v_flag & VXLOCK) {
		if (vp->v_vxproc == curthread) {
#if 0
			/* this can now occur in normal operation */
			log(LOG_INFO, "VXLOCK interlock avoided\n");
#endif
		} else {
			vp->v_flag |= VXWANT;
			msleep((caddr_t)vp, &vp->v_interlock, PINOD | PDROP,
			    "vget", 0);
			return (ENOENT);
		}
	}

	vp->v_usecount++;

	if (VSHOULDBUSY(vp))
		vbusy(vp);
	if (flags & LK_TYPE_MASK) {
		if ((error = vn_lock(vp, flags | LK_INTERLOCK, td)) != 0) {
			/*
			 * must expand vrele here because we do not want
			 * to call VOP_INACTIVE if the reference count
			 * drops back to zero since it was never really
			 * active. We must remove it from the free list
			 * before sleeping so that multiple processes do
			 * not try to recycle it.
			 */
			mtx_lock(&vp->v_interlock);
			vp->v_usecount--;
			if (VSHOULDFREE(vp))
				vfree(vp);
			else
				vlruvp(vp);
			mtx_unlock(&vp->v_interlock);
		}
		return (error);
	}
	mtx_unlock(&vp->v_interlock);
	return (0);
}

/* 
 * Increase the reference count of a vnode.
 */
void
vref(struct vnode *vp)
{
	mtx_lock(&vp->v_interlock);
	vp->v_usecount++;
	mtx_unlock(&vp->v_interlock);
}

/*
 * Vnode put/release.
 * If count drops to zero, call inactive routine and return to freelist.
 */
void
vrele(vp)
	struct vnode *vp;
{
	struct thread *td = curthread;	/* XXX */

	KASSERT(vp != NULL, ("vrele: null vp"));

	mtx_lock(&vp->v_interlock);

	/* Skip this v_writecount check if we're going to panic below. */
	KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
	    ("vrele: missed vn_close"));

	if (vp->v_usecount > 1) {

		vp->v_usecount--;
		mtx_unlock(&vp->v_interlock);

		return;
	}

	if (vp->v_usecount == 1) {
		vp->v_usecount--;
		/*
		 * We must call VOP_INACTIVE with the node locked.
		 * If we are doing a vput, the node is already locked,
		 * but, in the case of vrele, we must explicitly lock
		 * the vnode before calling VOP_INACTIVE.
		 */
		if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK, td) == 0)
			VOP_INACTIVE(vp, td);
		if (VSHOULDFREE(vp))
			vfree(vp);
		else
			vlruvp(vp);

	} else {
#ifdef DIAGNOSTIC
		vprint("vrele: negative ref count", vp);
		mtx_unlock(&vp->v_interlock);
#endif
		panic("vrele: negative ref cnt");
	}
}

/* 
 * Release an already locked vnode.  This give the same effects as
 * unlock+vrele(), but takes less time and avoids releasing and
 * re-aquiring the lock (as vrele() aquires the lock internally.)
 */
void
vput(vp)
	struct vnode *vp;
{
	struct thread *td = curthread;	/* XXX */

	GIANT_REQUIRED;

	KASSERT(vp != NULL, ("vput: null vp"));
	mtx_lock(&vp->v_interlock);
	/* Skip this v_writecount check if we're going to panic below. */
	KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
	    ("vput: missed vn_close"));

	if (vp->v_usecount > 1) {
		vp->v_usecount--;
		VOP_UNLOCK(vp, LK_INTERLOCK, td);
		return;
	}

	if (vp->v_usecount == 1) {
		vp->v_usecount--;
		/*
		 * We must call VOP_INACTIVE with the node locked.
		 * If we are doing a vput, the node is already locked,
		 * so we just need to release the vnode mutex.
		 */
		mtx_unlock(&vp->v_interlock);
		VOP_INACTIVE(vp, td);
		if (VSHOULDFREE(vp))
			vfree(vp);
		else
			vlruvp(vp);

	} else {
#ifdef DIAGNOSTIC
		vprint("vput: negative ref count", vp);
#endif
		panic("vput: negative ref cnt");
	}
}

/*
 * Somebody doesn't want the vnode recycled.
 */
void
vhold(vp)
	register struct vnode *vp;
{
	int s;

  	s = splbio();
	vp->v_holdcnt++;
	if (VSHOULDBUSY(vp))
		vbusy(vp);
	splx(s);
}

/*
 * Note that there is one less who cares about this vnode.  vdrop() is the
 * opposite of vhold().
 */
void
vdrop(vp)
	register struct vnode *vp;
{
	int s;

	s = splbio();
	if (vp->v_holdcnt <= 0)
		panic("vdrop: holdcnt");
	vp->v_holdcnt--;
	if (VSHOULDFREE(vp))
		vfree(vp);
	else
		vlruvp(vp);
	splx(s);
}

/*
 * Remove any vnodes in the vnode table belonging to mount point mp.
 *
 * If FORCECLOSE is not specified, there should not be any active ones,
 * return error if any are found (nb: this is a user error, not a
 * system error). If FORCECLOSE is specified, detach any active vnodes
 * that are found.
 *
 * If WRITECLOSE is set, only flush out regular file vnodes open for
 * writing.
 *
 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped.
 *
 * `rootrefs' specifies the base reference count for the root vnode
 * of this filesystem. The root vnode is considered busy if its
 * v_usecount exceeds this value. On a successful return, vflush()
 * will call vrele() on the root vnode exactly rootrefs times.
 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
 * be zero.
 */
#ifdef DIAGNOSTIC
static int busyprt = 0;		/* print out busy vnodes */
SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
#endif

int
vflush(mp, rootrefs, flags)
	struct mount *mp;
	int rootrefs;
	int flags;
{
	struct thread *td = curthread;	/* XXX */
	struct vnode *vp, *nvp, *rootvp = NULL;
	struct vattr vattr;
	int busy = 0, error;

	if (rootrefs > 0) {
		KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
		    ("vflush: bad args"));
		/*
		 * Get the filesystem root vnode. We can vput() it
		 * immediately, since with rootrefs > 0, it won't go away.
		 */
		if ((error = VFS_ROOT(mp, &rootvp)) != 0)
			return (error);
		vput(rootvp);
	}
	mtx_lock(&mntvnode_mtx);
loop:
	for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp; vp = nvp) {
		/*
		 * Make sure this vnode wasn't reclaimed in getnewvnode().
		 * Start over if it has (it won't be on the list anymore).
		 */
		if (vp->v_mount != mp)
			goto loop;
		nvp = TAILQ_NEXT(vp, v_nmntvnodes);

		mtx_unlock(&mntvnode_mtx);
		mtx_lock(&vp->v_interlock);
		/*
		 * Skip over a vnodes marked VSYSTEM.
		 */
		if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
			mtx_unlock(&vp->v_interlock);
			mtx_lock(&mntvnode_mtx);
			continue;
		}
		/*
		 * If WRITECLOSE is set, flush out unlinked but still open
		 * files (even if open only for reading) and regular file
		 * vnodes open for writing. 
		 */
		if ((flags & WRITECLOSE) &&
		    (vp->v_type == VNON ||
		    (VOP_GETATTR(vp, &vattr, td->td_proc->p_ucred, td) == 0 &&
		    vattr.va_nlink > 0)) &&
		    (vp->v_writecount == 0 || vp->v_type != VREG)) {
			mtx_unlock(&vp->v_interlock);
			mtx_lock(&mntvnode_mtx);
			continue;
		}

		/*
		 * With v_usecount == 0, all we need to do is clear out the
		 * vnode data structures and we are done.
		 */
		if (vp->v_usecount == 0) {
			vgonel(vp, td);
			mtx_lock(&mntvnode_mtx);
			continue;
		}

		/*
		 * If FORCECLOSE is set, forcibly close the vnode. For block
		 * or character devices, revert to an anonymous device. For
		 * all other files, just kill them.
		 */
		if (flags & FORCECLOSE) {
			if (vp->v_type != VCHR) {
				vgonel(vp, td);
			} else {
				vclean(vp, 0, td);
				vp->v_op = spec_vnodeop_p;
				insmntque(vp, (struct mount *) 0);
			}
			mtx_lock(&mntvnode_mtx);
			continue;
		}
#ifdef DIAGNOSTIC
		if (busyprt)
			vprint("vflush: busy vnode", vp);
#endif
		mtx_unlock(&vp->v_interlock);
		mtx_lock(&mntvnode_mtx);
		busy++;
	}
	mtx_unlock(&mntvnode_mtx);
	if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
		/*
		 * If just the root vnode is busy, and if its refcount
		 * is equal to `rootrefs', then go ahead and kill it.
		 */
		mtx_lock(&rootvp->v_interlock);
		KASSERT(busy > 0, ("vflush: not busy"));
		KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs"));
		if (busy == 1 && rootvp->v_usecount == rootrefs) {
			vgonel(rootvp, td);
			busy = 0;
		} else
			mtx_unlock(&rootvp->v_interlock);
	}
	if (busy)
		return (EBUSY);
	for (; rootrefs > 0; rootrefs--)
		vrele(rootvp);
	return (0);
}

/*
 * This moves a now (likely recyclable) vnode to the end of the
 * mountlist.  XXX However, it is temporarily disabled until we
 * can clean up ffs_sync() and friends, which have loop restart
 * conditions which this code causes to operate O(N^2).
 */
static void
vlruvp(struct vnode *vp)
{
#if 0
	struct mount *mp;

	if ((mp = vp->v_mount) != NULL) {
		mtx_lock(&mntvnode_mtx);
		TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
		TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
		mtx_unlock(&mntvnode_mtx);
	}
#endif
}

/*
 * Disassociate the underlying file system from a vnode.
 */
static void
vclean(vp, flags, td)
	struct vnode *vp;
	int flags;
	struct thread *td;
{
	int active;

	/*
	 * Check to see if the vnode is in use. If so we have to reference it
	 * before we clean it out so that its count cannot fall to zero and
	 * generate a race against ourselves to recycle it.
	 */
	if ((active = vp->v_usecount))
		vp->v_usecount++;

	/*
	 * Prevent the vnode from being recycled or brought into use while we
	 * clean it out.
	 */
	if (vp->v_flag & VXLOCK)
		panic("vclean: deadlock");
	vp->v_flag |= VXLOCK;
	vp->v_vxproc = curthread;
	/*
	 * Even if the count is zero, the VOP_INACTIVE routine may still
	 * have the object locked while it cleans it out. The VOP_LOCK
	 * ensures that the VOP_INACTIVE routine is done with its work.
	 * For active vnodes, it ensures that no other activity can
	 * occur while the underlying object is being cleaned out.
	 */
	VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td);

	/*
	 * Clean out any buffers associated with the vnode.
	 * If the flush fails, just toss the buffers.
	 */
	if (flags & DOCLOSE) {
		if (TAILQ_FIRST(&vp->v_dirtyblkhd) != NULL)
			(void) vn_write_suspend_wait(vp, NULL, V_WAIT);
		if (vinvalbuf(vp, V_SAVE, NOCRED, td, 0, 0) != 0)
			vinvalbuf(vp, 0, NOCRED, td, 0, 0);
	}

	VOP_DESTROYVOBJECT(vp);

	/*
	 * If purging an active vnode, it must be closed and
	 * deactivated before being reclaimed. Note that the
	 * VOP_INACTIVE will unlock the vnode.
	 */
	if (active) {
		if (flags & DOCLOSE)
			VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
		VOP_INACTIVE(vp, td);
	} else {
		/*
		 * Any other processes trying to obtain this lock must first
		 * wait for VXLOCK to clear, then call the new lock operation.
		 */
		VOP_UNLOCK(vp, 0, td);
	}
	/*
	 * Reclaim the vnode.
	 */
	if (VOP_RECLAIM(vp, td))
		panic("vclean: cannot reclaim");

	if (active) {
		/*
		 * Inline copy of vrele() since VOP_INACTIVE
		 * has already been called.
		 */
		mtx_lock(&vp->v_interlock);
		if (--vp->v_usecount <= 0) {
#ifdef DIAGNOSTIC
			if (vp->v_usecount < 0 || vp->v_writecount != 0) {
				vprint("vclean: bad ref count", vp);
				panic("vclean: ref cnt");
			}
#endif
			vfree(vp);
		}
		mtx_unlock(&vp->v_interlock);
	}

	cache_purge(vp);
	vp->v_vnlock = NULL;
	lockdestroy(&vp->v_lock);

	if (VSHOULDFREE(vp))
		vfree(vp);
	
	/*
	 * Done with purge, notify sleepers of the grim news.
	 */
	vp->v_op = dead_vnodeop_p;
	if (vp->v_pollinfo != NULL)
		vn_pollgone(vp);
	vp->v_tag = VT_NON;
	vp->v_flag &= ~VXLOCK;
	vp->v_vxproc = NULL;
	if (vp->v_flag & VXWANT) {
		vp->v_flag &= ~VXWANT;
		wakeup((caddr_t) vp);
	}
}

/*
 * Eliminate all activity associated with the requested vnode
 * and with all vnodes aliased to the requested vnode.
 */
int
vop_revoke(ap)
	struct vop_revoke_args /* {
		struct vnode *a_vp;
		int a_flags;
	} */ *ap;
{
	struct vnode *vp, *vq;
	dev_t dev;

	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));

	vp = ap->a_vp;
	/*
	 * If a vgone (or vclean) is already in progress,
	 * wait until it is done and return.
	 */
	if (vp->v_flag & VXLOCK) {
		vp->v_flag |= VXWANT;
		msleep((caddr_t)vp, &vp->v_interlock, PINOD | PDROP,
		    "vop_revokeall", 0);
		return (0);
	}
	dev = vp->v_rdev;
	for (;;) {
		mtx_lock(&spechash_mtx);
		vq = SLIST_FIRST(&dev->si_hlist);
		mtx_unlock(&spechash_mtx);
		if (!vq)
			break;
		vgone(vq);
	}
	return (0);
}

/*
 * Recycle an unused vnode to the front of the free list.
 * Release the passed interlock if the vnode will be recycled.
 */
int
vrecycle(vp, inter_lkp, td)
	struct vnode *vp;
	struct mtx *inter_lkp;
	struct thread *td;
{

	mtx_lock(&vp->v_interlock);
	if (vp->v_usecount == 0) {
		if (inter_lkp) {
			mtx_unlock(inter_lkp);
		}
		vgonel(vp, td);
		return (1);
	}
	mtx_unlock(&vp->v_interlock);
	return (0);
}

/*
 * Eliminate all activity associated with a vnode
 * in preparation for reuse.
 */
void
vgone(vp)
	register struct vnode *vp;
{
	struct thread *td = curthread;	/* XXX */

	mtx_lock(&vp->v_interlock);
	vgonel(vp, td);
}

/*
 * vgone, with the vp interlock held.
 */
void
vgonel(vp, td)
	struct vnode *vp;
	struct thread *td;
{
	int s;

	/*
	 * If a vgone (or vclean) is already in progress,
	 * wait until it is done and return.
	 */
	if (vp->v_flag & VXLOCK) {
		vp->v_flag |= VXWANT;
		msleep((caddr_t)vp, &vp->v_interlock, PINOD | PDROP,
		    "vgone", 0);
		return;
	}

	/*
	 * Clean out the filesystem specific data.
	 */
	vclean(vp, DOCLOSE, td);
	mtx_lock(&vp->v_interlock);

	/*
	 * Delete from old mount point vnode list, if on one.
	 */
	if (vp->v_mount != NULL)
		insmntque(vp, (struct mount *)0);
	/*
	 * If special device, remove it from special device alias list
	 * if it is on one.
	 */
	if (vp->v_type == VCHR && vp->v_rdev != NULL && vp->v_rdev != NODEV) {
		mtx_lock(&spechash_mtx);
		SLIST_REMOVE(&vp->v_rdev->si_hlist, vp, vnode, v_specnext);
		freedev(vp->v_rdev);
		mtx_unlock(&spechash_mtx);
		vp->v_rdev = NULL;
	}

	/*
	 * If it is on the freelist and not already at the head,
	 * move it to the head of the list. The test of the
	 * VDOOMED flag and the reference count of zero is because
	 * it will be removed from the free list by getnewvnode,
	 * but will not have its reference count incremented until
	 * after calling vgone. If the reference count were
	 * incremented first, vgone would (incorrectly) try to
	 * close the previous instance of the underlying object.
	 */
	if (vp->v_usecount == 0 && !(vp->v_flag & VDOOMED)) {
		s = splbio();
		mtx_lock(&vnode_free_list_mtx);
		if (vp->v_flag & VFREE)
			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
		else
			freevnodes++;
		vp->v_flag |= VFREE;
		TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
		mtx_unlock(&vnode_free_list_mtx);
		splx(s);
	}

	vp->v_type = VBAD;
	mtx_unlock(&vp->v_interlock);
}

/*
 * Lookup a vnode by device number.
 */
int
vfinddev(dev, type, vpp)
	dev_t dev;
	enum vtype type;
	struct vnode **vpp;
{
	struct vnode *vp;

	mtx_lock(&spechash_mtx);
	SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
		if (type == vp->v_type) {
			*vpp = vp;
			mtx_unlock(&spechash_mtx);
			return (1);
		}
	}
	mtx_unlock(&spechash_mtx);
	return (0);
}

/*
 * Calculate the total number of references to a special device.
 */
int
vcount(vp)
	struct vnode *vp;
{
	struct vnode *vq;
	int count;

	count = 0;
	mtx_lock(&spechash_mtx);
	SLIST_FOREACH(vq, &vp->v_rdev->si_hlist, v_specnext)
		count += vq->v_usecount;
	mtx_unlock(&spechash_mtx);
	return (count);
}

/*
 * Same as above, but using the dev_t as argument
 */
int
count_dev(dev)
	dev_t dev;
{
	struct vnode *vp;

	vp = SLIST_FIRST(&dev->si_hlist);
	if (vp == NULL)
		return (0);
	return(vcount(vp));
}

/*
 * Print out a description of a vnode.
 */
static char *typename[] =
{"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};

void
vprint(label, vp)
	char *label;
	struct vnode *vp;
{
	char buf[96];

	if (label != NULL)
		printf("%s: %p: ", label, (void *)vp);
	else
		printf("%p: ", (void *)vp);
	printf("type %s, usecount %d, writecount %d, refcount %d,",
	    typename[vp->v_type], vp->v_usecount, vp->v_writecount,
	    vp->v_holdcnt);
	buf[0] = '\0';
	if (vp->v_flag & VROOT)
		strcat(buf, "|VROOT");
	if (vp->v_flag & VTEXT)
		strcat(buf, "|VTEXT");
	if (vp->v_flag & VSYSTEM)
		strcat(buf, "|VSYSTEM");
	if (vp->v_flag & VXLOCK)
		strcat(buf, "|VXLOCK");
	if (vp->v_flag & VXWANT)
		strcat(buf, "|VXWANT");
	if (vp->v_flag & VBWAIT)
		strcat(buf, "|VBWAIT");
	if (vp->v_flag & VDOOMED)
		strcat(buf, "|VDOOMED");
	if (vp->v_flag & VFREE)
		strcat(buf, "|VFREE");
	if (vp->v_flag & VOBJBUF)
		strcat(buf, "|VOBJBUF");
	if (buf[0] != '\0')
		printf(" flags (%s)", &buf[1]);
	if (vp->v_data == NULL) {
		printf("\n");
	} else {
		printf("\n\t");
		VOP_PRINT(vp);
	}
}

#ifdef DDB
#include <ddb/ddb.h>
/*
 * List all of the locked vnodes in the system.
 * Called when debugging the kernel.
 */
DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
{
	struct thread *td = curthread;	/* XXX */
	struct mount *mp, *nmp;
	struct vnode *vp;

	printf("Locked vnodes\n");
	mtx_lock(&mountlist_mtx);
	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
		if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
			nmp = TAILQ_NEXT(mp, mnt_list);
			continue;
		}
		mtx_lock(&mntvnode_mtx);
		TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
			if (VOP_ISLOCKED(vp, NULL))
				vprint((char *)0, vp);
		}
		mtx_unlock(&mntvnode_mtx);
		mtx_lock(&mountlist_mtx);
		nmp = TAILQ_NEXT(mp, mnt_list);
		vfs_unbusy(mp, td);
	}
	mtx_unlock(&mountlist_mtx);
}
#endif

/*
 * Top level filesystem related information gathering.
 */
static int	sysctl_ovfs_conf __P((SYSCTL_HANDLER_ARGS));

static int
vfs_sysctl(SYSCTL_HANDLER_ARGS)
{
	int *name = (int *)arg1 - 1;	/* XXX */
	u_int namelen = arg2 + 1;	/* XXX */
	struct vfsconf *vfsp;

#if 1 || defined(COMPAT_PRELITE2)
	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
	if (namelen == 1)
		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
#endif

	/* XXX the below code does not compile; vfs_sysctl does not exist. */
#ifdef notyet
	/* all sysctl names at this level are at least name and field */
	if (namelen < 2)
		return (ENOTDIR);		/* overloaded */
	if (name[0] != VFS_GENERIC) {
		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
			if (vfsp->vfc_typenum == name[0])
				break;
		if (vfsp == NULL)
			return (EOPNOTSUPP);
		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
		    oldp, oldlenp, newp, newlen, td));
	}
#endif
	switch (name[1]) {
	case VFS_MAXTYPENUM:
		if (namelen != 2)
			return (ENOTDIR);
		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
	case VFS_CONF:
		if (namelen != 3)
			return (ENOTDIR);	/* overloaded */
		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
			if (vfsp->vfc_typenum == name[2])
				break;
		if (vfsp == NULL)
			return (EOPNOTSUPP);
		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
	}
	return (EOPNOTSUPP);
}

SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
	"Generic filesystem");

#if 1 || defined(COMPAT_PRELITE2)

static int
sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
{
	int error;
	struct vfsconf *vfsp;
	struct ovfsconf ovfs;

	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
		strcpy(ovfs.vfc_name, vfsp->vfc_name);
		ovfs.vfc_index = vfsp->vfc_typenum;
		ovfs.vfc_refcount = vfsp->vfc_refcount;
		ovfs.vfc_flags = vfsp->vfc_flags;
		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
		if (error)
			return error;
	}
	return 0;
}

#endif /* 1 || COMPAT_PRELITE2 */

#if COMPILING_LINT
#define KINFO_VNODESLOP	10
/*
 * Dump vnode list (via sysctl).
 * Copyout address of vnode followed by vnode.
 */
/* ARGSUSED */
static int
sysctl_vnode(SYSCTL_HANDLER_ARGS)
{
	struct thread *td = curthread;	/* XXX */
	struct mount *mp, *nmp;
	struct vnode *nvp, *vp;
	int error;

#define VPTRSZ	sizeof (struct vnode *)
#define VNODESZ	sizeof (struct vnode)

	req->lock = 0;
	if (!req->oldptr) /* Make an estimate */
		return (SYSCTL_OUT(req, 0,
			(numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ)));

	mtx_lock(&mountlist_mtx);
	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
		if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
			nmp = TAILQ_NEXT(mp, mnt_list);
			continue;
		}
		mtx_lock(&mntvnode_mtx);
again:
		for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
		     vp != NULL;
		     vp = nvp) {
			/*
			 * Check that the vp is still associated with
			 * this filesystem.  RACE: could have been
			 * recycled onto the same filesystem.
			 */
			if (vp->v_mount != mp)
				goto again;
			nvp = TAILQ_NEXT(vp, v_nmntvnodes);
			mtx_unlock(&mntvnode_mtx);
			if ((error = SYSCTL_OUT(req, &vp, VPTRSZ)) ||
			    (error = SYSCTL_OUT(req, vp, VNODESZ)))
				return (error);
			mtx_lock(&mntvnode_mtx);
		}
		mtx_unlock(&mntvnode_mtx);
		mtx_lock(&mountlist_mtx);
		nmp = TAILQ_NEXT(mp, mnt_list);
		vfs_unbusy(mp, td);
	}
	mtx_unlock(&mountlist_mtx);

	return (0);
}

/*
 * XXX
 * Exporting the vnode list on large systems causes them to crash.
 * Exporting the vnode list on medium systems causes sysctl to coredump.
 */
SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
	0, 0, sysctl_vnode, "S,vnode", "");
#endif

/*
 * Check to see if a filesystem is mounted on a block device.
 */
int
vfs_mountedon(vp)
	struct vnode *vp;
{

	if (vp->v_rdev->si_mountpoint != NULL)
		return (EBUSY);
	return (0);
}

/*
 * Unmount all filesystems. The list is traversed in reverse order
 * of mounting to avoid dependencies.
 */
void
vfs_unmountall()
{
	struct mount *mp;
	struct thread *td;
	int error;

	if (curthread != NULL)
		td = curthread;
	else
		td = FIRST_THREAD_IN_PROC(initproc); /* XXX XXX proc0? */
	/*
	 * Since this only runs when rebooting, it is not interlocked.
	 */
	while(!TAILQ_EMPTY(&mountlist)) {
		mp = TAILQ_LAST(&mountlist, mntlist);
		error = dounmount(mp, MNT_FORCE, td);
		if (error) {
			TAILQ_REMOVE(&mountlist, mp, mnt_list);
			printf("unmount of %s failed (",
			    mp->mnt_stat.f_mntonname);
			if (error == EBUSY)
				printf("BUSY)\n");
			else
				printf("%d)\n", error);
		} else {
			/* The unmount has removed mp from the mountlist */
		}
	}
}

/*
 * perform msync on all vnodes under a mount point
 * the mount point must be locked.
 */
void
vfs_msync(struct mount *mp, int flags)
{
	struct vnode *vp, *nvp;
	struct vm_object *obj;
	int tries;

	GIANT_REQUIRED;

	tries = 5;
	mtx_lock(&mntvnode_mtx);
loop:
	for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
		if (vp->v_mount != mp) {
			if (--tries > 0)
				goto loop;
			break;
		}
		nvp = TAILQ_NEXT(vp, v_nmntvnodes);

		if (vp->v_flag & VXLOCK)	/* XXX: what if MNT_WAIT? */
			continue;

		if (vp->v_flag & VNOSYNC)	/* unlinked, skip it */
			continue;

		if ((vp->v_flag & VOBJDIRTY) &&
		    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
			mtx_unlock(&mntvnode_mtx);
			if (!vget(vp,
			    LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ, curthread)) {
				if (VOP_GETVOBJECT(vp, &obj) == 0) {
					vm_object_page_clean(obj, 0, 0,
					    flags == MNT_WAIT ?
					    OBJPC_SYNC : OBJPC_NOSYNC);
				}
				vput(vp);
			}
			mtx_lock(&mntvnode_mtx);
			if (TAILQ_NEXT(vp, v_nmntvnodes) != nvp) {
				if (--tries > 0)
					goto loop;
				break;
			}
		}
	}
	mtx_unlock(&mntvnode_mtx);
}

/*
 * Create the VM object needed for VMIO and mmap support.  This
 * is done for all VREG files in the system.  Some filesystems might
 * afford the additional metadata buffering capability of the
 * VMIO code by making the device node be VMIO mode also.
 *
 * vp must be locked when vfs_object_create is called.
 */
int
vfs_object_create(vp, td, cred)
	struct vnode *vp;
	struct thread *td;
	struct ucred *cred;
{
	GIANT_REQUIRED;
	return (VOP_CREATEVOBJECT(vp, cred, td));
}

/*
 * Mark a vnode as free, putting it up for recycling.
 */
void
vfree(vp)
	struct vnode *vp;
{
	int s;

	s = splbio();
	mtx_lock(&vnode_free_list_mtx);
	KASSERT((vp->v_flag & VFREE) == 0, ("vnode already free"));
	if (vp->v_flag & VAGE) {
		TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
	} else {
		TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
	}
	freevnodes++;
	mtx_unlock(&vnode_free_list_mtx);
	vp->v_flag &= ~VAGE;
	vp->v_flag |= VFREE;
	splx(s);
}

/* 
 * Opposite of vfree() - mark a vnode as in use.
 */
void
vbusy(vp)
	struct vnode *vp;
{
	int s;

	s = splbio();
	mtx_lock(&vnode_free_list_mtx);
	KASSERT((vp->v_flag & VFREE) != 0, ("vnode not free"));
	TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
	freevnodes--;
	mtx_unlock(&vnode_free_list_mtx);
	vp->v_flag &= ~(VFREE|VAGE);
	splx(s);
}

/*
 * Record a process's interest in events which might happen to
 * a vnode.  Because poll uses the historic select-style interface
 * internally, this routine serves as both the ``check for any
 * pending events'' and the ``record my interest in future events''
 * functions.  (These are done together, while the lock is held,
 * to avoid race conditions.)
 */
int
vn_pollrecord(vp, td, events)
	struct vnode *vp;
	struct thread *td;
	short events;
{

	if (vp->v_pollinfo == NULL)
		v_addpollinfo(vp);	
	mtx_lock(&vp->v_pollinfo->vpi_lock);
	if (vp->v_pollinfo->vpi_revents & events) {
		/*
		 * This leaves events we are not interested
		 * in available for the other process which
		 * which presumably had requested them
		 * (otherwise they would never have been
		 * recorded).
		 */
		events &= vp->v_pollinfo->vpi_revents;
		vp->v_pollinfo->vpi_revents &= ~events;

		mtx_unlock(&vp->v_pollinfo->vpi_lock);
		return events;
	}
	vp->v_pollinfo->vpi_events |= events;
	selrecord(td, &vp->v_pollinfo->vpi_selinfo);
	mtx_unlock(&vp->v_pollinfo->vpi_lock);
	return 0;
}

/*
 * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
 * it is possible for us to miss an event due to race conditions, but
 * that condition is expected to be rare, so for the moment it is the
 * preferred interface.
 */
void
vn_pollevent(vp, events)
	struct vnode *vp;
	short events;
{

	if (vp->v_pollinfo == NULL)
		v_addpollinfo(vp);	
	mtx_lock(&vp->v_pollinfo->vpi_lock);
	if (vp->v_pollinfo->vpi_events & events) {
		/*
		 * We clear vpi_events so that we don't
		 * call selwakeup() twice if two events are
		 * posted before the polling process(es) is
		 * awakened.  This also ensures that we take at
		 * most one selwakeup() if the polling process
		 * is no longer interested.  However, it does
		 * mean that only one event can be noticed at
		 * a time.  (Perhaps we should only clear those
		 * event bits which we note?) XXX
		 */
		vp->v_pollinfo->vpi_events = 0;	/* &= ~events ??? */
		vp->v_pollinfo->vpi_revents |= events;
		selwakeup(&vp->v_pollinfo->vpi_selinfo);
	}
	mtx_unlock(&vp->v_pollinfo->vpi_lock);
}

/*
 * Wake up anyone polling on vp because it is being revoked.
 * This depends on dead_poll() returning POLLHUP for correct
 * behavior.
 */
void
vn_pollgone(vp)
	struct vnode *vp;
{

	mtx_lock(&vp->v_pollinfo->vpi_lock);
        VN_KNOTE(vp, NOTE_REVOKE);
	if (vp->v_pollinfo->vpi_events) {
		vp->v_pollinfo->vpi_events = 0;
		selwakeup(&vp->v_pollinfo->vpi_selinfo);
	}
	mtx_unlock(&vp->v_pollinfo->vpi_lock);
}



/*
 * Routine to create and manage a filesystem syncer vnode.
 */
#define sync_close ((int (*) __P((struct  vop_close_args *)))nullop)
static int	sync_fsync __P((struct  vop_fsync_args *));
static int	sync_inactive __P((struct  vop_inactive_args *));
static int	sync_reclaim  __P((struct  vop_reclaim_args *));
#define sync_lock ((int (*) __P((struct  vop_lock_args *)))vop_nolock)
#define sync_unlock ((int (*) __P((struct  vop_unlock_args *)))vop_nounlock)
static int	sync_print __P((struct vop_print_args *));
#define sync_islocked ((int(*) __P((struct vop_islocked_args *)))vop_noislocked)

static vop_t **sync_vnodeop_p;
static struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
	{ &vop_default_desc,	(vop_t *) vop_eopnotsupp },
	{ &vop_close_desc,	(vop_t *) sync_close },		/* close */
	{ &vop_fsync_desc,	(vop_t *) sync_fsync },		/* fsync */
	{ &vop_inactive_desc,	(vop_t *) sync_inactive },	/* inactive */
	{ &vop_reclaim_desc,	(vop_t *) sync_reclaim },	/* reclaim */
	{ &vop_lock_desc,	(vop_t *) sync_lock },		/* lock */
	{ &vop_unlock_desc,	(vop_t *) sync_unlock },	/* unlock */
	{ &vop_print_desc,	(vop_t *) sync_print },		/* print */
	{ &vop_islocked_desc,	(vop_t *) sync_islocked },	/* islocked */
	{ NULL, NULL }
};
static struct vnodeopv_desc sync_vnodeop_opv_desc =
	{ &sync_vnodeop_p, sync_vnodeop_entries };

VNODEOP_SET(sync_vnodeop_opv_desc);

/*
 * Create a new filesystem syncer vnode for the specified mount point.
 */
int
vfs_allocate_syncvnode(mp)
	struct mount *mp;
{
	struct vnode *vp;
	static long start, incr, next;
	int error;

	/* Allocate a new vnode */
	if ((error = getnewvnode(VT_VFS, mp, sync_vnodeop_p, &vp)) != 0) {
		mp->mnt_syncer = NULL;
		return (error);
	}
	vp->v_type = VNON;
	/*
	 * Place the vnode onto the syncer worklist. We attempt to
	 * scatter them about on the list so that they will go off
	 * at evenly distributed times even if all the filesystems
	 * are mounted at once.
	 */
	next += incr;
	if (next == 0 || next > syncer_maxdelay) {
		start /= 2;
		incr /= 2;
		if (start == 0) {
			start = syncer_maxdelay / 2;
			incr = syncer_maxdelay;
		}
		next = start;
	}
	vn_syncer_add_to_worklist(vp, syncdelay > 0 ? next % syncdelay : 0);
	mp->mnt_syncer = vp;
	return (0);
}

/*
 * Do a lazy sync of the filesystem.
 */
static int
sync_fsync(ap)
	struct vop_fsync_args /* {
		struct vnode *a_vp;
		struct ucred *a_cred;
		int a_waitfor;
		struct thread *a_td;
	} */ *ap;
{
	struct vnode *syncvp = ap->a_vp;
	struct mount *mp = syncvp->v_mount;
	struct thread *td = ap->a_td;
	int asyncflag;

	/*
	 * We only need to do something if this is a lazy evaluation.
	 */
	if (ap->a_waitfor != MNT_LAZY)
		return (0);

	/*
	 * Move ourselves to the back of the sync list.
	 */
	vn_syncer_add_to_worklist(syncvp, syncdelay);

	/*
	 * Walk the list of vnodes pushing all that are dirty and
	 * not already on the sync list.
	 */
	mtx_lock(&mountlist_mtx);
	if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &mountlist_mtx, td) != 0) {
		mtx_unlock(&mountlist_mtx);
		return (0);
	}
	if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
		vfs_unbusy(mp, td);
		return (0);
	}
	asyncflag = mp->mnt_flag & MNT_ASYNC;
	mp->mnt_flag &= ~MNT_ASYNC;
	vfs_msync(mp, MNT_NOWAIT);
	VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
	if (asyncflag)
		mp->mnt_flag |= MNT_ASYNC;
	vn_finished_write(mp);
	vfs_unbusy(mp, td);
	return (0);
}

/*
 * The syncer vnode is no referenced.
 */
static int
sync_inactive(ap)
	struct vop_inactive_args /* {
		struct vnode *a_vp;
		struct thread *a_td;
	} */ *ap;
{

	vgone(ap->a_vp);
	return (0);
}

/*
 * The syncer vnode is no longer needed and is being decommissioned.
 *
 * Modifications to the worklist must be protected at splbio().
 */
static int
sync_reclaim(ap)
	struct vop_reclaim_args /* {
		struct vnode *a_vp;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	int s;

	s = splbio();
	vp->v_mount->mnt_syncer = NULL;
	if (vp->v_flag & VONWORKLST) {
		LIST_REMOVE(vp, v_synclist);
		vp->v_flag &= ~VONWORKLST;
	}
	splx(s);

	return (0);
}

/*
 * Print out a syncer vnode.
 */
static int
sync_print(ap)
	struct vop_print_args /* {
		struct vnode *a_vp;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;

	printf("syncer vnode");
	if (vp->v_vnlock != NULL)
		lockmgr_printinfo(vp->v_vnlock);
	printf("\n");
	return (0);
}

/*
 * extract the dev_t from a VCHR
 */
dev_t
vn_todev(vp)
	struct vnode *vp;
{
	if (vp->v_type != VCHR)
		return (NODEV);
	return (vp->v_rdev);
}

/*
 * Check if vnode represents a disk device
 */
int
vn_isdisk(vp, errp)
	struct vnode *vp;
	int *errp;
{
	struct cdevsw *cdevsw;

	if (vp->v_type != VCHR) {
		if (errp != NULL)
			*errp = ENOTBLK;
		return (0);
	}
	if (vp->v_rdev == NULL) {
		if (errp != NULL)
			*errp = ENXIO;
		return (0);
	}
	cdevsw = devsw(vp->v_rdev);
	if (cdevsw == NULL) {
		if (errp != NULL)
			*errp = ENXIO;
		return (0);
	}
	if (!(cdevsw->d_flags & D_DISK)) {
		if (errp != NULL)
			*errp = ENOTBLK;
		return (0);
	}
	if (errp != NULL)
		*errp = 0;
	return (1);
}

/*
 * Free data allocated by namei(); see namei(9) for details.
 */
void
NDFREE(ndp, flags)
     struct nameidata *ndp;
     const uint flags;
{
	if (!(flags & NDF_NO_FREE_PNBUF) &&
	    (ndp->ni_cnd.cn_flags & HASBUF)) {
		zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
		ndp->ni_cnd.cn_flags &= ~HASBUF;
	}
	if (!(flags & NDF_NO_DVP_UNLOCK) &&
	    (ndp->ni_cnd.cn_flags & LOCKPARENT) &&
	    ndp->ni_dvp != ndp->ni_vp)
		VOP_UNLOCK(ndp->ni_dvp, 0, ndp->ni_cnd.cn_thread);
	if (!(flags & NDF_NO_DVP_RELE) &&
	    (ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) {
		vrele(ndp->ni_dvp);
		ndp->ni_dvp = NULL;
	}
	if (!(flags & NDF_NO_VP_UNLOCK) &&
	    (ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp)
		VOP_UNLOCK(ndp->ni_vp, 0, ndp->ni_cnd.cn_thread);
	if (!(flags & NDF_NO_VP_RELE) &&
	    ndp->ni_vp) {
		vrele(ndp->ni_vp);
		ndp->ni_vp = NULL;
	}
	if (!(flags & NDF_NO_STARTDIR_RELE) &&
	    (ndp->ni_cnd.cn_flags & SAVESTART)) {
		vrele(ndp->ni_startdir);
		ndp->ni_startdir = NULL;
	}
}

/*
 * Common file system object access control check routine.  Accepts a
 * vnode's type, "mode", uid and gid, requested access mode, credentials,
 * and optional call-by-reference privused argument allowing vaccess()
 * to indicate to the caller whether privilege was used to satisfy the
 * request.  Returns 0 on success, or an errno on failure.
 */
int
vaccess(type, file_mode, file_uid, file_gid, acc_mode, cred, privused)
	enum vtype type;
	mode_t file_mode;
	uid_t file_uid;
	gid_t file_gid;
	mode_t acc_mode;
	struct ucred *cred;
	int *privused;
{
	mode_t dac_granted;
#ifdef CAPABILITIES
	mode_t cap_granted;
#endif

	/*
	 * Look for a normal, non-privileged way to access the file/directory
	 * as requested.  If it exists, go with that.
	 */

	if (privused != NULL)
		*privused = 0;

	dac_granted = 0;

	/* Check the owner. */
	if (cred->cr_uid == file_uid) {
		dac_granted |= VADMIN;
		if (file_mode & S_IXUSR)
			dac_granted |= VEXEC;
		if (file_mode & S_IRUSR)
			dac_granted |= VREAD;
		if (file_mode & S_IWUSR)
			dac_granted |= VWRITE;

		if ((acc_mode & dac_granted) == acc_mode)
			return (0);

		goto privcheck;
	}

	/* Otherwise, check the groups (first match) */
	if (groupmember(file_gid, cred)) {
		if (file_mode & S_IXGRP)
			dac_granted |= VEXEC;
		if (file_mode & S_IRGRP)
			dac_granted |= VREAD;
		if (file_mode & S_IWGRP)
			dac_granted |= VWRITE;

		if ((acc_mode & dac_granted) == acc_mode)
			return (0);

		goto privcheck;
	}

	/* Otherwise, check everyone else. */
	if (file_mode & S_IXOTH)
		dac_granted |= VEXEC;
	if (file_mode & S_IROTH)
		dac_granted |= VREAD;
	if (file_mode & S_IWOTH)
		dac_granted |= VWRITE;
	if ((acc_mode & dac_granted) == acc_mode)
		return (0);

privcheck:
	if (!suser_xxx(cred, NULL, PRISON_ROOT)) {
		/* XXX audit: privilege used */
		if (privused != NULL)
			*privused = 1;
		return (0);
	}

#ifdef CAPABILITIES
	/*
	 * Build a capability mask to determine if the set of capabilities
	 * satisfies the requirements when combined with the granted mask
	 * from above.
	 * For each capability, if the capability is required, bitwise
	 * or the request type onto the cap_granted mask.
	 */
	cap_granted = 0;

	if (type == VDIR) {
		/*
		 * For directories, use CAP_DAC_READ_SEARCH to satisfy
		 * VEXEC requests, instead of CAP_DAC_EXECUTE.
		 */
		if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
		    !cap_check(cred, NULL, CAP_DAC_READ_SEARCH, PRISON_ROOT))
			cap_granted |= VEXEC;
	} else {
		if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
		    !cap_check(cred, NULL, CAP_DAC_EXECUTE, PRISON_ROOT))
			cap_granted |= VEXEC;
	}

	if ((acc_mode & VREAD) && ((dac_granted & VREAD) == 0) &&
	    !cap_check(cred, NULL, CAP_DAC_READ_SEARCH, PRISON_ROOT))
		cap_granted |= VREAD;

	if ((acc_mode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
	    !cap_check(cred, NULL, CAP_DAC_WRITE, PRISON_ROOT))
		cap_granted |= VWRITE;

	if ((acc_mode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
	    !cap_check(cred, NULL, CAP_FOWNER, PRISON_ROOT))
		cap_granted |= VADMIN;

	if ((acc_mode & (cap_granted | dac_granted)) == acc_mode) {
		/* XXX audit: privilege used */
		if (privused != NULL)
			*privused = 1;
		return (0);
	}
#endif

	return ((acc_mode & VADMIN) ? EPERM : EACCES);
}

OpenPOWER on IntegriCloud