Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
/*
*  Copyright (c) 2001 The Regents of the University of Michigan.
*  All rights reserved.
*
*  Kendrick Smith <kmsmith@umich.edu>
*  Andy Adamson <kandros@umich.edu>
*
*  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. 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 ``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.
*
*/

#include <linux/file.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/ratelimit.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/addr.h>
#include <linux/jhash.h>
#include <linux/string_helpers.h>
#include <linux/fsnotify.h>
#include <linux/nfs_ssc.h>
#include "xdr4.h"
#include "xdr4cb.h"
#include "vfs.h"
#include "current_stateid.h"

#include "netns.h"
#include "pnfs.h"
#include "filecache.h"
#include "trace.h"

#define NFSDDBG_FACILITY                NFSDDBG_PROC

#define all_ones {{~0,~0},~0}
static const stateid_t one_stateid = {
	.si_generation = ~0,
	.si_opaque = all_ones,
};
static const stateid_t zero_stateid = {
	/* all fields zero */
};
static const stateid_t currentstateid = {
	.si_generation = 1,
};
static const stateid_t close_stateid = {
	.si_generation = 0xffffffffU,
};

static u64 current_sessionid = 1;

#define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(stateid_t)))
#define ONE_STATEID(stateid)  (!memcmp((stateid), &one_stateid, sizeof(stateid_t)))
#define CURRENT_STATEID(stateid) (!memcmp((stateid), &currentstateid, sizeof(stateid_t)))
#define CLOSE_STATEID(stateid)  (!memcmp((stateid), &close_stateid, sizeof(stateid_t)))

/* forward declarations */
static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
static void nfs4_free_ol_stateid(struct nfs4_stid *stid);
void nfsd4_end_grace(struct nfsd_net *nn);
static void _free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps);

/* Locking: */

/*
 * Currently used for the del_recall_lru and file hash table.  In an
 * effort to decrease the scope of the client_mutex, this spinlock may
 * eventually cover more:
 */
static DEFINE_SPINLOCK(state_lock);

enum nfsd4_st_mutex_lock_subclass {
	OPEN_STATEID_MUTEX = 0,
	LOCK_STATEID_MUTEX = 1,
};

/*
 * A waitqueue for all in-progress 4.0 CLOSE operations that are waiting for
 * the refcount on the open stateid to drop.
 */
static DECLARE_WAIT_QUEUE_HEAD(close_wq);

/*
 * A waitqueue where a writer to clients/#/ctl destroying a client can
 * wait for cl_rpc_users to drop to 0 and then for the client to be
 * unhashed.
 */
static DECLARE_WAIT_QUEUE_HEAD(expiry_wq);

static struct kmem_cache *client_slab;
static struct kmem_cache *openowner_slab;
static struct kmem_cache *lockowner_slab;
static struct kmem_cache *file_slab;
static struct kmem_cache *stateid_slab;
static struct kmem_cache *deleg_slab;
static struct kmem_cache *odstate_slab;

static void free_session(struct nfsd4_session *);

static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;

static struct workqueue_struct *laundry_wq;

int nfsd4_create_laundry_wq(void)
{
	int rc = 0;

	laundry_wq = alloc_workqueue("%s", WQ_UNBOUND, 0, "nfsd4");
	if (laundry_wq == NULL)
		rc = -ENOMEM;
	return rc;
}

void nfsd4_destroy_laundry_wq(void)
{
	destroy_workqueue(laundry_wq);
}

static bool is_session_dead(struct nfsd4_session *ses)
{
	return ses->se_flags & NFS4_SESSION_DEAD;
}

static __be32 mark_session_dead_locked(struct nfsd4_session *ses, int ref_held_by_me)
{
	if (atomic_read(&ses->se_ref) > ref_held_by_me)
		return nfserr_jukebox;
	ses->se_flags |= NFS4_SESSION_DEAD;
	return nfs_ok;
}

static bool is_client_expired(struct nfs4_client *clp)
{
	return clp->cl_time == 0;
}

static void nfsd4_dec_courtesy_client_count(struct nfsd_net *nn,
					struct nfs4_client *clp)
{
	if (clp->cl_state != NFSD4_ACTIVE)
		atomic_add_unless(&nn->nfsd_courtesy_clients, -1, 0);
}

static __be32 get_client_locked(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	if (is_client_expired(clp))
		return nfserr_expired;
	atomic_inc(&clp->cl_rpc_users);
	nfsd4_dec_courtesy_client_count(nn, clp);
	clp->cl_state = NFSD4_ACTIVE;
	return nfs_ok;
}

/* must be called under the client_lock */
static inline void
renew_client_locked(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	if (is_client_expired(clp)) {
		WARN_ON(1);
		printk("%s: client (clientid %08x/%08x) already expired\n",
			__func__,
			clp->cl_clientid.cl_boot,
			clp->cl_clientid.cl_id);
		return;
	}

	list_move_tail(&clp->cl_lru, &nn->client_lru);
	clp->cl_time = ktime_get_boottime_seconds();
	nfsd4_dec_courtesy_client_count(nn, clp);
	clp->cl_state = NFSD4_ACTIVE;
}

static void put_client_renew_locked(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	if (!atomic_dec_and_test(&clp->cl_rpc_users))
		return;
	if (!is_client_expired(clp))
		renew_client_locked(clp);
	else
		wake_up_all(&expiry_wq);
}

static void put_client_renew(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	if (!atomic_dec_and_lock(&clp->cl_rpc_users, &nn->client_lock))
		return;
	if (!is_client_expired(clp))
		renew_client_locked(clp);
	else
		wake_up_all(&expiry_wq);
	spin_unlock(&nn->client_lock);
}

static __be32 nfsd4_get_session_locked(struct nfsd4_session *ses)
{
	__be32 status;

	if (is_session_dead(ses))
		return nfserr_badsession;
	status = get_client_locked(ses->se_client);
	if (status)
		return status;
	atomic_inc(&ses->se_ref);
	return nfs_ok;
}

static void nfsd4_put_session_locked(struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	if (atomic_dec_and_test(&ses->se_ref) && is_session_dead(ses))
		free_session(ses);
	put_client_renew_locked(clp);
}

static void nfsd4_put_session(struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	spin_lock(&nn->client_lock);
	nfsd4_put_session_locked(ses);
	spin_unlock(&nn->client_lock);
}

static struct nfsd4_blocked_lock *
find_blocked_lock(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
			struct nfsd_net *nn)
{
	struct nfsd4_blocked_lock *cur, *found = NULL;

	spin_lock(&nn->blocked_locks_lock);
	list_for_each_entry(cur, &lo->lo_blocked, nbl_list) {
		if (fh_match(fh, &cur->nbl_fh)) {
			list_del_init(&cur->nbl_list);
			WARN_ON(list_empty(&cur->nbl_lru));
			list_del_init(&cur->nbl_lru);
			found = cur;
			break;
		}
	}
	spin_unlock(&nn->blocked_locks_lock);
	if (found)
		locks_delete_block(&found->nbl_lock);
	return found;
}

static struct nfsd4_blocked_lock *
find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
			struct nfsd_net *nn)
{
	struct nfsd4_blocked_lock *nbl;

	nbl = find_blocked_lock(lo, fh, nn);
	if (!nbl) {
		nbl= kmalloc(sizeof(*nbl), GFP_KERNEL);
		if (nbl) {
			INIT_LIST_HEAD(&nbl->nbl_list);
			INIT_LIST_HEAD(&nbl->nbl_lru);
			fh_copy_shallow(&nbl->nbl_fh, fh);
			locks_init_lock(&nbl->nbl_lock);
			kref_init(&nbl->nbl_kref);
			nfsd4_init_cb(&nbl->nbl_cb, lo->lo_owner.so_client,
					&nfsd4_cb_notify_lock_ops,
					NFSPROC4_CLNT_CB_NOTIFY_LOCK);
		}
	}
	return nbl;
}

static void
free_nbl(struct kref *kref)
{
	struct nfsd4_blocked_lock *nbl;

	nbl = container_of(kref, struct nfsd4_blocked_lock, nbl_kref);
	kfree(nbl);
}

static void
free_blocked_lock(struct nfsd4_blocked_lock *nbl)
{
	locks_delete_block(&nbl->nbl_lock);
	locks_release_private(&nbl->nbl_lock);
	kref_put(&nbl->nbl_kref, free_nbl);
}

static void
remove_blocked_locks(struct nfs4_lockowner *lo)
{
	struct nfs4_client *clp = lo->lo_owner.so_client;
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
	struct nfsd4_blocked_lock *nbl;
	LIST_HEAD(reaplist);

	/* Dequeue all blocked locks */
	spin_lock(&nn->blocked_locks_lock);
	while (!list_empty(&lo->lo_blocked)) {
		nbl = list_first_entry(&lo->lo_blocked,
					struct nfsd4_blocked_lock,
					nbl_list);
		list_del_init(&nbl->nbl_list);
		WARN_ON(list_empty(&nbl->nbl_lru));
		list_move(&nbl->nbl_lru, &reaplist);
	}
	spin_unlock(&nn->blocked_locks_lock);

	/* Now free them */
	while (!list_empty(&reaplist)) {
		nbl = list_first_entry(&reaplist, struct nfsd4_blocked_lock,
					nbl_lru);
		list_del_init(&nbl->nbl_lru);
		free_blocked_lock(nbl);
	}
}

static void
nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb)
{
	struct nfsd4_blocked_lock	*nbl = container_of(cb,
						struct nfsd4_blocked_lock, nbl_cb);
	locks_delete_block(&nbl->nbl_lock);
}

static int
nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
{
	trace_nfsd_cb_notify_lock_done(&zero_stateid, task);

	/*
	 * Since this is just an optimization, we don't try very hard if it
	 * turns out not to succeed. We'll requeue it on NFS4ERR_DELAY, and
	 * just quit trying on anything else.
	 */
	switch (task->tk_status) {
	case -NFS4ERR_DELAY:
		rpc_delay(task, 1 * HZ);
		return 0;
	default:
		return 1;
	}
}

static void
nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
{
	struct nfsd4_blocked_lock	*nbl = container_of(cb,
						struct nfsd4_blocked_lock, nbl_cb);

	free_blocked_lock(nbl);
}

static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
	.prepare	= nfsd4_cb_notify_lock_prepare,
	.done		= nfsd4_cb_notify_lock_done,
	.release	= nfsd4_cb_notify_lock_release,
};

/*
 * We store the NONE, READ, WRITE, and BOTH bits separately in the
 * st_{access,deny}_bmap field of the stateid, in order to track not
 * only what share bits are currently in force, but also what
 * combinations of share bits previous opens have used.  This allows us
 * to enforce the recommendation in
 * https://datatracker.ietf.org/doc/html/rfc7530#section-16.19.4 that
 * the server return an error if the client attempt to downgrade to a
 * combination of share bits not explicable by closing some of its
 * previous opens.
 *
 * This enforcement is arguably incomplete, since we don't keep
 * track of access/deny bit combinations; so, e.g., we allow:
 *
 *	OPEN allow read, deny write
 *	OPEN allow both, deny none
 *	DOWNGRADE allow read, deny none
 *
 * which we should reject.
 *
 * But you could also argue that our current code is already overkill,
 * since it only exists to return NFS4ERR_INVAL on incorrect client
 * behavior.
 */
static unsigned int
bmap_to_share_mode(unsigned long bmap)
{
	int i;
	unsigned int access = 0;

	for (i = 1; i < 4; i++) {
		if (test_bit(i, &bmap))
			access |= i;
	}
	return access;
}

/* set share access for a given stateid */
static inline void
set_access(u32 access, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << access;

	WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
	stp->st_access_bmap |= mask;
}

/* clear share access for a given stateid */
static inline void
clear_access(u32 access, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << access;

	WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
	stp->st_access_bmap &= ~mask;
}

/* test whether a given stateid has access */
static inline bool
test_access(u32 access, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << access;

	return (bool)(stp->st_access_bmap & mask);
}

/* set share deny for a given stateid */
static inline void
set_deny(u32 deny, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << deny;

	WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
	stp->st_deny_bmap |= mask;
}

/* clear share deny for a given stateid */
static inline void
clear_deny(u32 deny, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << deny;

	WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
	stp->st_deny_bmap &= ~mask;
}

/* test whether a given stateid is denying specific access */
static inline bool
test_deny(u32 deny, struct nfs4_ol_stateid *stp)
{
	unsigned char mask = 1 << deny;

	return (bool)(stp->st_deny_bmap & mask);
}

static int nfs4_access_to_omode(u32 access)
{
	switch (access & NFS4_SHARE_ACCESS_BOTH) {
	case NFS4_SHARE_ACCESS_READ:
		return O_RDONLY;
	case NFS4_SHARE_ACCESS_WRITE:
		return O_WRONLY;
	case NFS4_SHARE_ACCESS_BOTH:
		return O_RDWR;
	}
	WARN_ON_ONCE(1);
	return O_RDONLY;
}

static inline int
access_permit_read(struct nfs4_ol_stateid *stp)
{
	return test_access(NFS4_SHARE_ACCESS_READ, stp) ||
		test_access(NFS4_SHARE_ACCESS_BOTH, stp) ||
		test_access(NFS4_SHARE_ACCESS_WRITE, stp);
}

static inline int
access_permit_write(struct nfs4_ol_stateid *stp)
{
	return test_access(NFS4_SHARE_ACCESS_WRITE, stp) ||
		test_access(NFS4_SHARE_ACCESS_BOTH, stp);
}

static inline struct nfs4_stateowner *
nfs4_get_stateowner(struct nfs4_stateowner *sop)
{
	atomic_inc(&sop->so_count);
	return sop;
}

static int
same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner)
{
	return (sop->so_owner.len == owner->len) &&
		0 == memcmp(sop->so_owner.data, owner->data, owner->len);
}

static struct nfs4_openowner *
find_openstateowner_str_locked(unsigned int hashval, struct nfsd4_open *open,
			struct nfs4_client *clp)
{
	struct nfs4_stateowner *so;

	lockdep_assert_held(&clp->cl_lock);

	list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[hashval],
			    so_strhash) {
		if (!so->so_is_open_owner)
			continue;
		if (same_owner_str(so, &open->op_owner))
			return openowner(nfs4_get_stateowner(so));
	}
	return NULL;
}

static struct nfs4_openowner *
find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
			struct nfs4_client *clp)
{
	struct nfs4_openowner *oo;

	spin_lock(&clp->cl_lock);
	oo = find_openstateowner_str_locked(hashval, open, clp);
	spin_unlock(&clp->cl_lock);
	return oo;
}

static inline u32
opaque_hashval(const void *ptr, int nbytes)
{
	unsigned char *cptr = (unsigned char *) ptr;

	u32 x = 0;
	while (nbytes--) {
		x *= 37;
		x += *cptr++;
	}
	return x;
}

static void nfsd4_free_file_rcu(struct rcu_head *rcu)
{
	struct nfs4_file *fp = container_of(rcu, struct nfs4_file, fi_rcu);

	kmem_cache_free(file_slab, fp);
}

void
put_nfs4_file(struct nfs4_file *fi)
{
	might_lock(&state_lock);

	if (refcount_dec_and_lock(&fi->fi_ref, &state_lock)) {
		hlist_del_rcu(&fi->fi_hash);
		spin_unlock(&state_lock);
		WARN_ON_ONCE(!list_empty(&fi->fi_clnt_odstate));
		WARN_ON_ONCE(!list_empty(&fi->fi_delegations));
		call_rcu(&fi->fi_rcu, nfsd4_free_file_rcu);
	}
}

static struct nfsd_file *
__nfs4_get_fd(struct nfs4_file *f, int oflag)
{
	if (f->fi_fds[oflag])
		return nfsd_file_get(f->fi_fds[oflag]);
	return NULL;
}

static struct nfsd_file *
find_writeable_file_locked(struct nfs4_file *f)
{
	struct nfsd_file *ret;

	lockdep_assert_held(&f->fi_lock);

	ret = __nfs4_get_fd(f, O_WRONLY);
	if (!ret)
		ret = __nfs4_get_fd(f, O_RDWR);
	return ret;
}

static struct nfsd_file *
find_writeable_file(struct nfs4_file *f)
{
	struct nfsd_file *ret;

	spin_lock(&f->fi_lock);
	ret = find_writeable_file_locked(f);
	spin_unlock(&f->fi_lock);

	return ret;
}

static struct nfsd_file *
find_readable_file_locked(struct nfs4_file *f)
{
	struct nfsd_file *ret;

	lockdep_assert_held(&f->fi_lock);

	ret = __nfs4_get_fd(f, O_RDONLY);
	if (!ret)
		ret = __nfs4_get_fd(f, O_RDWR);
	return ret;
}

static struct nfsd_file *
find_readable_file(struct nfs4_file *f)
{
	struct nfsd_file *ret;

	spin_lock(&f->fi_lock);
	ret = find_readable_file_locked(f);
	spin_unlock(&f->fi_lock);

	return ret;
}

struct nfsd_file *
find_any_file(struct nfs4_file *f)
{
	struct nfsd_file *ret;

	if (!f)
		return NULL;
	spin_lock(&f->fi_lock);
	ret = __nfs4_get_fd(f, O_RDWR);
	if (!ret) {
		ret = __nfs4_get_fd(f, O_WRONLY);
		if (!ret)
			ret = __nfs4_get_fd(f, O_RDONLY);
	}
	spin_unlock(&f->fi_lock);
	return ret;
}

static struct nfsd_file *find_any_file_locked(struct nfs4_file *f)
{
	lockdep_assert_held(&f->fi_lock);

	if (f->fi_fds[O_RDWR])
		return f->fi_fds[O_RDWR];
	if (f->fi_fds[O_WRONLY])
		return f->fi_fds[O_WRONLY];
	if (f->fi_fds[O_RDONLY])
		return f->fi_fds[O_RDONLY];
	return NULL;
}

static struct nfsd_file *find_deleg_file_locked(struct nfs4_file *f)
{
	lockdep_assert_held(&f->fi_lock);

	if (f->fi_deleg_file)
		return f->fi_deleg_file;
	return NULL;
}

static atomic_long_t num_delegations;
unsigned long max_delegations;

/*
 * Open owner state (share locks)
 */

/* hash tables for lock and open owners */
#define OWNER_HASH_BITS              8
#define OWNER_HASH_SIZE             (1 << OWNER_HASH_BITS)
#define OWNER_HASH_MASK             (OWNER_HASH_SIZE - 1)

static unsigned int ownerstr_hashval(struct xdr_netobj *ownername)
{
	unsigned int ret;

	ret = opaque_hashval(ownername->data, ownername->len);
	return ret & OWNER_HASH_MASK;
}

/* hash table for nfs4_file */
#define FILE_HASH_BITS                   8
#define FILE_HASH_SIZE                  (1 << FILE_HASH_BITS)

static unsigned int file_hashval(struct svc_fh *fh)
{
	struct inode *inode = d_inode(fh->fh_dentry);

	/* XXX: why not (here & in file cache) use inode? */
	return (unsigned int)hash_long(inode->i_ino, FILE_HASH_BITS);
}

static struct hlist_head file_hashtbl[FILE_HASH_SIZE];

/*
 * Check if courtesy clients have conflicting access and resolve it if possible
 *
 * access:  is op_share_access if share_access is true.
 *	    Check if access mode, op_share_access, would conflict with
 *	    the current deny mode of the file 'fp'.
 * access:  is op_share_deny if share_access is false.
 *	    Check if the deny mode, op_share_deny, would conflict with
 *	    current access of the file 'fp'.
 * stp:     skip checking this entry.
 * new_stp: normal open, not open upgrade.
 *
 * Function returns:
 *	false - access/deny mode conflict with normal client.
 *	true  - no conflict or conflict with courtesy client(s) is resolved.
 */
static bool
nfs4_resolve_deny_conflicts_locked(struct nfs4_file *fp, bool new_stp,
		struct nfs4_ol_stateid *stp, u32 access, bool share_access)
{
	struct nfs4_ol_stateid *st;
	bool resolvable = true;
	unsigned char bmap;
	struct nfsd_net *nn;
	struct nfs4_client *clp;

	lockdep_assert_held(&fp->fi_lock);
	list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
		/* ignore lock stateid */
		if (st->st_openstp)
			continue;
		if (st == stp && new_stp)
			continue;
		/* check file access against deny mode or vice versa */
		bmap = share_access ? st->st_deny_bmap : st->st_access_bmap;
		if (!(access & bmap_to_share_mode(bmap)))
			continue;
		clp = st->st_stid.sc_client;
		if (try_to_expire_client(clp))
			continue;
		resolvable = false;
		break;
	}
	if (resolvable) {
		clp = stp->st_stid.sc_client;
		nn = net_generic(clp->net, nfsd_net_id);
		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
	}
	return resolvable;
}

static void
__nfs4_file_get_access(struct nfs4_file *fp, u32 access)
{
	lockdep_assert_held(&fp->fi_lock);

	if (access & NFS4_SHARE_ACCESS_WRITE)
		atomic_inc(&fp->fi_access[O_WRONLY]);
	if (access & NFS4_SHARE_ACCESS_READ)
		atomic_inc(&fp->fi_access[O_RDONLY]);
}

static __be32
nfs4_file_get_access(struct nfs4_file *fp, u32 access)
{
	lockdep_assert_held(&fp->fi_lock);

	/* Does this access mode make sense? */
	if (access & ~NFS4_SHARE_ACCESS_BOTH)
		return nfserr_inval;

	/* Does it conflict with a deny mode already set? */
	if ((access & fp->fi_share_deny) != 0)
		return nfserr_share_denied;

	__nfs4_file_get_access(fp, access);
	return nfs_ok;
}

static __be32 nfs4_file_check_deny(struct nfs4_file *fp, u32 deny)
{
	/* Common case is that there is no deny mode. */
	if (deny) {
		/* Does this deny mode make sense? */
		if (deny & ~NFS4_SHARE_DENY_BOTH)
			return nfserr_inval;

		if ((deny & NFS4_SHARE_DENY_READ) &&
		    atomic_read(&fp->fi_access[O_RDONLY]))
			return nfserr_share_denied;

		if ((deny & NFS4_SHARE_DENY_WRITE) &&
		    atomic_read(&fp->fi_access[O_WRONLY]))
			return nfserr_share_denied;
	}
	return nfs_ok;
}

static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag)
{
	might_lock(&fp->fi_lock);

	if (atomic_dec_and_lock(&fp->fi_access[oflag], &fp->fi_lock)) {
		struct nfsd_file *f1 = NULL;
		struct nfsd_file *f2 = NULL;

		swap(f1, fp->fi_fds[oflag]);
		if (atomic_read(&fp->fi_access[1 - oflag]) == 0)
			swap(f2, fp->fi_fds[O_RDWR]);
		spin_unlock(&fp->fi_lock);
		if (f1)
			nfsd_file_put(f1);
		if (f2)
			nfsd_file_put(f2);
	}
}

static void nfs4_file_put_access(struct nfs4_file *fp, u32 access)
{
	WARN_ON_ONCE(access & ~NFS4_SHARE_ACCESS_BOTH);

	if (access & NFS4_SHARE_ACCESS_WRITE)
		__nfs4_file_put_access(fp, O_WRONLY);
	if (access & NFS4_SHARE_ACCESS_READ)
		__nfs4_file_put_access(fp, O_RDONLY);
}

/*
 * Allocate a new open/delegation state counter. This is needed for
 * pNFS for proper return on close semantics.
 *
 * Note that we only allocate it for pNFS-enabled exports, otherwise
 * all pointers to struct nfs4_clnt_odstate are always NULL.
 */
static struct nfs4_clnt_odstate *
alloc_clnt_odstate(struct nfs4_client *clp)
{
	struct nfs4_clnt_odstate *co;

	co = kmem_cache_zalloc(odstate_slab, GFP_KERNEL);
	if (co) {
		co->co_client = clp;
		refcount_set(&co->co_odcount, 1);
	}
	return co;
}

static void
hash_clnt_odstate_locked(struct nfs4_clnt_odstate *co)
{
	struct nfs4_file *fp = co->co_file;

	lockdep_assert_held(&fp->fi_lock);
	list_add(&co->co_perfile, &fp->fi_clnt_odstate);
}

static inline void
get_clnt_odstate(struct nfs4_clnt_odstate *co)
{
	if (co)
		refcount_inc(&co->co_odcount);
}

static void
put_clnt_odstate(struct nfs4_clnt_odstate *co)
{
	struct nfs4_file *fp;

	if (!co)
		return;

	fp = co->co_file;
	if (refcount_dec_and_lock(&co->co_odcount, &fp->fi_lock)) {
		list_del(&co->co_perfile);
		spin_unlock(&fp->fi_lock);

		nfsd4_return_all_file_layouts(co->co_client, fp);
		kmem_cache_free(odstate_slab, co);
	}
}

static struct nfs4_clnt_odstate *
find_or_hash_clnt_odstate(struct nfs4_file *fp, struct nfs4_clnt_odstate *new)
{
	struct nfs4_clnt_odstate *co;
	struct nfs4_client *cl;

	if (!new)
		return NULL;

	cl = new->co_client;

	spin_lock(&fp->fi_lock);
	list_for_each_entry(co, &fp->fi_clnt_odstate, co_perfile) {
		if (co->co_client == cl) {
			get_clnt_odstate(co);
			goto out;
		}
	}
	co = new;
	co->co_file = fp;
	hash_clnt_odstate_locked(new);
out:
	spin_unlock(&fp->fi_lock);
	return co;
}

struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *slab,
				  void (*sc_free)(struct nfs4_stid *))
{
	struct nfs4_stid *stid;
	int new_id;

	stid = kmem_cache_zalloc(slab, GFP_KERNEL);
	if (!stid)
		return NULL;

	idr_preload(GFP_KERNEL);
	spin_lock(&cl->cl_lock);
	/* Reserving 0 for start of file in nfsdfs "states" file: */
	new_id = idr_alloc_cyclic(&cl->cl_stateids, stid, 1, 0, GFP_NOWAIT);
	spin_unlock(&cl->cl_lock);
	idr_preload_end();
	if (new_id < 0)
		goto out_free;

	stid->sc_free = sc_free;
	stid->sc_client = cl;
	stid->sc_stateid.si_opaque.so_id = new_id;
	stid->sc_stateid.si_opaque.so_clid = cl->cl_clientid;
	/* Will be incremented before return to client: */
	refcount_set(&stid->sc_count, 1);
	spin_lock_init(&stid->sc_lock);
	INIT_LIST_HEAD(&stid->sc_cp_list);

	/*
	 * It shouldn't be a problem to reuse an opaque stateid value.
	 * I don't think it is for 4.1.  But with 4.0 I worry that, for
	 * example, a stray write retransmission could be accepted by
	 * the server when it should have been rejected.  Therefore,
	 * adopt a trick from the sctp code to attempt to maximize the
	 * amount of time until an id is reused, by ensuring they always
	 * "increase" (mod INT_MAX):
	 */
	return stid;
out_free:
	kmem_cache_free(slab, stid);
	return NULL;
}

/*
 * Create a unique stateid_t to represent each COPY.
 */
static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
			      unsigned char cs_type)
{
	int new_id;

	stid->cs_stid.si_opaque.so_clid.cl_boot = (u32)nn->boot_time;
	stid->cs_stid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;

	idr_preload(GFP_KERNEL);
	spin_lock(&nn->s2s_cp_lock);
	new_id = idr_alloc_cyclic(&nn->s2s_cp_stateids, stid, 0, 0, GFP_NOWAIT);
	stid->cs_stid.si_opaque.so_id = new_id;
	stid->cs_stid.si_generation = 1;
	spin_unlock(&nn->s2s_cp_lock);
	idr_preload_end();
	if (new_id < 0)
		return 0;
	stid->cs_type = cs_type;
	return 1;
}

int nfs4_init_copy_state(struct nfsd_net *nn, struct nfsd4_copy *copy)
{
	return nfs4_init_cp_state(nn, &copy->cp_stateid, NFS4_COPY_STID);
}

struct nfs4_cpntf_state *nfs4_alloc_init_cpntf_state(struct nfsd_net *nn,
						     struct nfs4_stid *p_stid)
{
	struct nfs4_cpntf_state *cps;

	cps = kzalloc(sizeof(struct nfs4_cpntf_state), GFP_KERNEL);
	if (!cps)
		return NULL;
	cps->cpntf_time = ktime_get_boottime_seconds();
	refcount_set(&cps->cp_stateid.cs_count, 1);
	if (!nfs4_init_cp_state(nn, &cps->cp_stateid, NFS4_COPYNOTIFY_STID))
		goto out_free;
	spin_lock(&nn->s2s_cp_lock);
	list_add(&cps->cp_list, &p_stid->sc_cp_list);
	spin_unlock(&nn->s2s_cp_lock);
	return cps;
out_free:
	kfree(cps);
	return NULL;
}

void nfs4_free_copy_state(struct nfsd4_copy *copy)
{
	struct nfsd_net *nn;

	if (copy->cp_stateid.cs_type != NFS4_COPY_STID)
		return;
	nn = net_generic(copy->cp_clp->net, nfsd_net_id);
	spin_lock(&nn->s2s_cp_lock);
	idr_remove(&nn->s2s_cp_stateids,
		   copy->cp_stateid.cs_stid.si_opaque.so_id);
	spin_unlock(&nn->s2s_cp_lock);
}

static void nfs4_free_cpntf_statelist(struct net *net, struct nfs4_stid *stid)
{
	struct nfs4_cpntf_state *cps;
	struct nfsd_net *nn;

	nn = net_generic(net, nfsd_net_id);
	spin_lock(&nn->s2s_cp_lock);
	while (!list_empty(&stid->sc_cp_list)) {
		cps = list_first_entry(&stid->sc_cp_list,
				       struct nfs4_cpntf_state, cp_list);
		_free_cpntf_state_locked(nn, cps);
	}
	spin_unlock(&nn->s2s_cp_lock);
}

static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
{
	struct nfs4_stid *stid;

	stid = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_ol_stateid);
	if (!stid)
		return NULL;

	return openlockstateid(stid);
}

static void nfs4_free_deleg(struct nfs4_stid *stid)
{
	struct nfs4_delegation *dp = delegstateid(stid);

	WARN_ON_ONCE(!list_empty(&stid->sc_cp_list));
	WARN_ON_ONCE(!list_empty(&dp->dl_perfile));
	WARN_ON_ONCE(!list_empty(&dp->dl_perclnt));
	WARN_ON_ONCE(!list_empty(&dp->dl_recall_lru));
	kmem_cache_free(deleg_slab, stid);
	atomic_long_dec(&num_delegations);
}

/*
 * When we recall a delegation, we should be careful not to hand it
 * out again straight away.
 * To ensure this we keep a pair of bloom filters ('new' and 'old')
 * in which the filehandles of recalled delegations are "stored".
 * If a filehandle appear in either filter, a delegation is blocked.
 * When a delegation is recalled, the filehandle is stored in the "new"
 * filter.
 * Every 30 seconds we swap the filters and clear the "new" one,
 * unless both are empty of course.
 *
 * Each filter is 256 bits.  We hash the filehandle to 32bit and use the
 * low 3 bytes as hash-table indices.
 *
 * 'blocked_delegations_lock', which is always taken in block_delegations(),
 * is used to manage concurrent access.  Testing does not need the lock
 * except when swapping the two filters.
 */
static DEFINE_SPINLOCK(blocked_delegations_lock);
static struct bloom_pair {
	int	entries, old_entries;
	time64_t swap_time;
	int	new; /* index into 'set' */
	DECLARE_BITMAP(set[2], 256);
} blocked_delegations;

static int delegation_blocked(struct knfsd_fh *fh)
{
	u32 hash;
	struct bloom_pair *bd = &blocked_delegations;

	if (bd->entries == 0)
		return 0;
	if (ktime_get_seconds() - bd->swap_time > 30) {
		spin_lock(&blocked_delegations_lock);
		if (ktime_get_seconds() - bd->swap_time > 30) {
			bd->entries -= bd->old_entries;
			bd->old_entries = bd->entries;
			memset(bd->set[bd->new], 0,
			       sizeof(bd->set[0]));
			bd->new = 1-bd->new;
			bd->swap_time = ktime_get_seconds();
		}
		spin_unlock(&blocked_delegations_lock);
	}
	hash = jhash(&fh->fh_raw, fh->fh_size, 0);
	if (test_bit(hash&255, bd->set[0]) &&
	    test_bit((hash>>8)&255, bd->set[0]) &&
	    test_bit((hash>>16)&255, bd->set[0]))
		return 1;

	if (test_bit(hash&255, bd->set[1]) &&
	    test_bit((hash>>8)&255, bd->set[1]) &&
	    test_bit((hash>>16)&255, bd->set[1]))
		return 1;

	return 0;
}

static void block_delegations(struct knfsd_fh *fh)
{
	u32 hash;
	struct bloom_pair *bd = &blocked_delegations;

	hash = jhash(&fh->fh_raw, fh->fh_size, 0);

	spin_lock(&blocked_delegations_lock);
	__set_bit(hash&255, bd->set[bd->new]);
	__set_bit((hash>>8)&255, bd->set[bd->new]);
	__set_bit((hash>>16)&255, bd->set[bd->new]);
	if (bd->entries == 0)
		bd->swap_time = ktime_get_seconds();
	bd->entries += 1;
	spin_unlock(&blocked_delegations_lock);
}

static struct nfs4_delegation *
alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
		 struct nfs4_clnt_odstate *odstate)
{
	struct nfs4_delegation *dp;
	long n;

	dprintk("NFSD alloc_init_deleg\n");
	n = atomic_long_inc_return(&num_delegations);
	if (n < 0 || n > max_delegations)
		goto out_dec;
	if (delegation_blocked(&fp->fi_fhandle))
		goto out_dec;
	dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab, nfs4_free_deleg));
	if (dp == NULL)
		goto out_dec;

	/*
	 * delegation seqid's are never incremented.  The 4.1 special
	 * meaning of seqid 0 isn't meaningful, really, but let's avoid
	 * 0 anyway just for consistency and use 1:
	 */
	dp->dl_stid.sc_stateid.si_generation = 1;
	INIT_LIST_HEAD(&dp->dl_perfile);
	INIT_LIST_HEAD(&dp->dl_perclnt);
	INIT_LIST_HEAD(&dp->dl_recall_lru);
	dp->dl_clnt_odstate = odstate;
	get_clnt_odstate(odstate);
	dp->dl_type = NFS4_OPEN_DELEGATE_READ;
	dp->dl_retries = 1;
	dp->dl_recalled = false;
	nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
		      &nfsd4_cb_recall_ops, NFSPROC4_CLNT_CB_RECALL);
	get_nfs4_file(fp);
	dp->dl_stid.sc_file = fp;
	return dp;
out_dec:
	atomic_long_dec(&num_delegations);
	return NULL;
}

void
nfs4_put_stid(struct nfs4_stid *s)
{
	struct nfs4_file *fp = s->sc_file;
	struct nfs4_client *clp = s->sc_client;

	might_lock(&clp->cl_lock);

	if (!refcount_dec_and_lock(&s->sc_count, &clp->cl_lock)) {
		wake_up_all(&close_wq);
		return;
	}
	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
	nfs4_free_cpntf_statelist(clp->net, s);
	spin_unlock(&clp->cl_lock);
	s->sc_free(s);
	if (fp)
		put_nfs4_file(fp);
}

void
nfs4_inc_and_copy_stateid(stateid_t *dst, struct nfs4_stid *stid)
{
	stateid_t *src = &stid->sc_stateid;

	spin_lock(&stid->sc_lock);
	if (unlikely(++src->si_generation == 0))
		src->si_generation = 1;
	memcpy(dst, src, sizeof(*dst));
	spin_unlock(&stid->sc_lock);
}

static void put_deleg_file(struct nfs4_file *fp)
{
	struct nfsd_file *nf = NULL;

	spin_lock(&fp->fi_lock);
	if (--fp->fi_delegees == 0)
		swap(nf, fp->fi_deleg_file);
	spin_unlock(&fp->fi_lock);

	if (nf)
		nfsd_file_put(nf);
}

static void nfs4_unlock_deleg_lease(struct nfs4_delegation *dp)
{
	struct nfs4_file *fp = dp->dl_stid.sc_file;
	struct nfsd_file *nf = fp->fi_deleg_file;

	WARN_ON_ONCE(!fp->fi_delegees);

	vfs_setlease(nf->nf_file, F_UNLCK, NULL, (void **)&dp);
	put_deleg_file(fp);
}

static void destroy_unhashed_deleg(struct nfs4_delegation *dp)
{
	put_clnt_odstate(dp->dl_clnt_odstate);
	nfs4_unlock_deleg_lease(dp);
	nfs4_put_stid(&dp->dl_stid);
}

void nfs4_unhash_stid(struct nfs4_stid *s)
{
	s->sc_type = 0;
}

/**
 * nfs4_delegation_exists - Discover if this delegation already exists
 * @clp:     a pointer to the nfs4_client we're granting a delegation to
 * @fp:      a pointer to the nfs4_file we're granting a delegation on
 *
 * Return:
 *      On success: true iff an existing delegation is found
 */

static bool
nfs4_delegation_exists(struct nfs4_client *clp, struct nfs4_file *fp)
{
	struct nfs4_delegation *searchdp = NULL;
	struct nfs4_client *searchclp = NULL;

	lockdep_assert_held(&state_lock);
	lockdep_assert_held(&fp->fi_lock);

	list_for_each_entry(searchdp, &fp->fi_delegations, dl_perfile) {
		searchclp = searchdp->dl_stid.sc_client;
		if (clp == searchclp) {
			return true;
		}
	}
	return false;
}

/**
 * hash_delegation_locked - Add a delegation to the appropriate lists
 * @dp:     a pointer to the nfs4_delegation we are adding.
 * @fp:     a pointer to the nfs4_file we're granting a delegation on
 *
 * Return:
 *      On success: NULL if the delegation was successfully hashed.
 *
 *      On error: -EAGAIN if one was previously granted to this
 *                 nfs4_client for this nfs4_file. Delegation is not hashed.
 *
 */

static int
hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp)
{
	struct nfs4_client *clp = dp->dl_stid.sc_client;

	lockdep_assert_held(&state_lock);
	lockdep_assert_held(&fp->fi_lock);

	if (nfs4_delegation_exists(clp, fp))
		return -EAGAIN;
	refcount_inc(&dp->dl_stid.sc_count);
	dp->dl_stid.sc_type = NFS4_DELEG_STID;
	list_add(&dp->dl_perfile, &fp->fi_delegations);
	list_add(&dp->dl_perclnt, &clp->cl_delegations);
	return 0;
}

static bool delegation_hashed(struct nfs4_delegation *dp)
{
	return !(list_empty(&dp->dl_perfile));
}

static bool
unhash_delegation_locked(struct nfs4_delegation *dp)
{
	struct nfs4_file *fp = dp->dl_stid.sc_file;

	lockdep_assert_held(&state_lock);

	if (!delegation_hashed(dp))
		return false;

	dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID;
	/* Ensure that deleg break won't try to requeue it */
	++dp->dl_time;
	spin_lock(&fp->fi_lock);
	list_del_init(&dp->dl_perclnt);
	list_del_init(&dp->dl_recall_lru);
	list_del_init(&dp->dl_perfile);
	spin_unlock(&fp->fi_lock);
	return true;
}

static void destroy_delegation(struct nfs4_delegation *dp)
{
	bool unhashed;

	spin_lock(&state_lock);
	unhashed = unhash_delegation_locked(dp);
	spin_unlock(&state_lock);
	if (unhashed)
		destroy_unhashed_deleg(dp);
}

static void revoke_delegation(struct nfs4_delegation *dp)
{
	struct nfs4_client *clp = dp->dl_stid.sc_client;

	WARN_ON(!list_empty(&dp->dl_recall_lru));

	if (clp->cl_minorversion) {
		dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID;
		refcount_inc(&dp->dl_stid.sc_count);
		spin_lock(&clp->cl_lock);
		list_add(&dp->dl_recall_lru, &clp->cl_revoked);
		spin_unlock(&clp->cl_lock);
	}
	destroy_unhashed_deleg(dp);
}

/* 
 * SETCLIENTID state 
 */

static unsigned int clientid_hashval(u32 id)
{
	return id & CLIENT_HASH_MASK;
}

static unsigned int clientstr_hashval(struct xdr_netobj name)
{
	return opaque_hashval(name.data, 8) & CLIENT_HASH_MASK;
}

/*
 * A stateid that had a deny mode associated with it is being released
 * or downgraded. Recalculate the deny mode on the file.
 */
static void
recalculate_deny_mode(struct nfs4_file *fp)
{
	struct nfs4_ol_stateid *stp;

	spin_lock(&fp->fi_lock);
	fp->fi_share_deny = 0;
	list_for_each_entry(stp, &fp->fi_stateids, st_perfile)
		fp->fi_share_deny |= bmap_to_share_mode(stp->st_deny_bmap);
	spin_unlock(&fp->fi_lock);
}

static void
reset_union_bmap_deny(u32 deny, struct nfs4_ol_stateid *stp)
{
	int i;
	bool change = false;

	for (i = 1; i < 4; i++) {
		if ((i & deny) != i) {
			change = true;
			clear_deny(i, stp);
		}
	}

	/* Recalculate per-file deny mode if there was a change */
	if (change)
		recalculate_deny_mode(stp->st_stid.sc_file);
}

/* release all access and file references for a given stateid */
static void
release_all_access(struct nfs4_ol_stateid *stp)
{
	int i;
	struct nfs4_file *fp = stp->st_stid.sc_file;

	if (fp && stp->st_deny_bmap != 0)
		recalculate_deny_mode(fp);

	for (i = 1; i < 4; i++) {
		if (test_access(i, stp))
			nfs4_file_put_access(stp->st_stid.sc_file, i);
		clear_access(i, stp);
	}
}

static inline void nfs4_free_stateowner(struct nfs4_stateowner *sop)
{
	kfree(sop->so_owner.data);
	sop->so_ops->so_free(sop);
}

static void nfs4_put_stateowner(struct nfs4_stateowner *sop)
{
	struct nfs4_client *clp = sop->so_client;

	might_lock(&clp->cl_lock);

	if (!atomic_dec_and_lock(&sop->so_count, &clp->cl_lock))
		return;
	sop->so_ops->so_unhash(sop);
	spin_unlock(&clp->cl_lock);
	nfs4_free_stateowner(sop);
}

static bool
nfs4_ol_stateid_unhashed(const struct nfs4_ol_stateid *stp)
{
	return list_empty(&stp->st_perfile);
}

static bool unhash_ol_stateid(struct nfs4_ol_stateid *stp)
{
	struct nfs4_file *fp = stp->st_stid.sc_file;

	lockdep_assert_held(&stp->st_stateowner->so_client->cl_lock);

	if (list_empty(&stp->st_perfile))
		return false;

	spin_lock(&fp->fi_lock);
	list_del_init(&stp->st_perfile);
	spin_unlock(&fp->fi_lock);
	list_del(&stp->st_perstateowner);
	return true;
}

static void nfs4_free_ol_stateid(struct nfs4_stid *stid)
{
	struct nfs4_ol_stateid *stp = openlockstateid(stid);

	put_clnt_odstate(stp->st_clnt_odstate);
	release_all_access(stp);
	if (stp->st_stateowner)
		nfs4_put_stateowner(stp->st_stateowner);
	WARN_ON(!list_empty(&stid->sc_cp_list));
	kmem_cache_free(stateid_slab, stid);
}

static void nfs4_free_lock_stateid(struct nfs4_stid *stid)
{
	struct nfs4_ol_stateid *stp = openlockstateid(stid);
	struct nfs4_lockowner *lo = lockowner(stp->st_stateowner);
	struct nfsd_file *nf;

	nf = find_any_file(stp->st_stid.sc_file);
	if (nf) {
		get_file(nf->nf_file);
		filp_close(nf->nf_file, (fl_owner_t)lo);
		nfsd_file_put(nf);
	}
	nfs4_free_ol_stateid(stid);
}

/*
 * Put the persistent reference to an already unhashed generic stateid, while
 * holding the cl_lock. If it's the last reference, then put it onto the
 * reaplist for later destruction.
 */
static void put_ol_stateid_locked(struct nfs4_ol_stateid *stp,
				       struct list_head *reaplist)
{
	struct nfs4_stid *s = &stp->st_stid;
	struct nfs4_client *clp = s->sc_client;

	lockdep_assert_held(&clp->cl_lock);

	WARN_ON_ONCE(!list_empty(&stp->st_locks));

	if (!refcount_dec_and_test(&s->sc_count)) {
		wake_up_all(&close_wq);
		return;
	}

	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
	list_add(&stp->st_locks, reaplist);
}

static bool unhash_lock_stateid(struct nfs4_ol_stateid *stp)
{
	lockdep_assert_held(&stp->st_stid.sc_client->cl_lock);

	if (!unhash_ol_stateid(stp))
		return false;
	list_del_init(&stp->st_locks);
	nfs4_unhash_stid(&stp->st_stid);
	return true;
}

static void release_lock_stateid(struct nfs4_ol_stateid *stp)
{
	struct nfs4_client *clp = stp->st_stid.sc_client;
	bool unhashed;

	spin_lock(&clp->cl_lock);
	unhashed = unhash_lock_stateid(stp);
	spin_unlock(&clp->cl_lock);
	if (unhashed)
		nfs4_put_stid(&stp->st_stid);
}

static void unhash_lockowner_locked(struct nfs4_lockowner *lo)
{
	struct nfs4_client *clp = lo->lo_owner.so_client;

	lockdep_assert_held(&clp->cl_lock);

	list_del_init(&lo->lo_owner.so_strhash);
}

/*
 * Free a list of generic stateids that were collected earlier after being
 * fully unhashed.
 */
static void
free_ol_stateid_reaplist(struct list_head *reaplist)
{
	struct nfs4_ol_stateid *stp;
	struct nfs4_file *fp;

	might_sleep();

	while (!list_empty(reaplist)) {
		stp = list_first_entry(reaplist, struct nfs4_ol_stateid,
				       st_locks);
		list_del(&stp->st_locks);
		fp = stp->st_stid.sc_file;
		stp->st_stid.sc_free(&stp->st_stid);
		if (fp)
			put_nfs4_file(fp);
	}
}

static void release_open_stateid_locks(struct nfs4_ol_stateid *open_stp,
				       struct list_head *reaplist)
{
	struct nfs4_ol_stateid *stp;

	lockdep_assert_held(&open_stp->st_stid.sc_client->cl_lock);

	while (!list_empty(&open_stp->st_locks)) {
		stp = list_entry(open_stp->st_locks.next,
				struct nfs4_ol_stateid, st_locks);
		WARN_ON(!unhash_lock_stateid(stp));
		put_ol_stateid_locked(stp, reaplist);
	}
}

static bool unhash_open_stateid(struct nfs4_ol_stateid *stp,
				struct list_head *reaplist)
{
	lockdep_assert_held(&stp->st_stid.sc_client->cl_lock);

	if (!unhash_ol_stateid(stp))
		return false;
	release_open_stateid_locks(stp, reaplist);
	return true;
}

static void release_open_stateid(struct nfs4_ol_stateid *stp)
{
	LIST_HEAD(reaplist);

	spin_lock(&stp->st_stid.sc_client->cl_lock);
	if (unhash_open_stateid(stp, &reaplist))
		put_ol_stateid_locked(stp, &reaplist);
	spin_unlock(&stp->st_stid.sc_client->cl_lock);
	free_ol_stateid_reaplist(&reaplist);
}

static void unhash_openowner_locked(struct nfs4_openowner *oo)
{
	struct nfs4_client *clp = oo->oo_owner.so_client;

	lockdep_assert_held(&clp->cl_lock);

	list_del_init(&oo->oo_owner.so_strhash);
	list_del_init(&oo->oo_perclient);
}

static void release_last_closed_stateid(struct nfs4_openowner *oo)
{
	struct nfsd_net *nn = net_generic(oo->oo_owner.so_client->net,
					  nfsd_net_id);
	struct nfs4_ol_stateid *s;

	spin_lock(&nn->client_lock);
	s = oo->oo_last_closed_stid;
	if (s) {
		list_del_init(&oo->oo_close_lru);
		oo->oo_last_closed_stid = NULL;
	}
	spin_unlock(&nn->client_lock);
	if (s)
		nfs4_put_stid(&s->st_stid);
}

static void release_openowner(struct nfs4_openowner *oo)
{
	struct nfs4_ol_stateid *stp;
	struct nfs4_client *clp = oo->oo_owner.so_client;
	struct list_head reaplist;

	INIT_LIST_HEAD(&reaplist);

	spin_lock(&clp->cl_lock);
	unhash_openowner_locked(oo);
	while (!list_empty(&oo->oo_owner.so_stateids)) {
		stp = list_first_entry(&oo->oo_owner.so_stateids,
				struct nfs4_ol_stateid, st_perstateowner);
		if (unhash_open_stateid(stp, &reaplist))
			put_ol_stateid_locked(stp, &reaplist);
	}
	spin_unlock(&clp->cl_lock);
	free_ol_stateid_reaplist(&reaplist);
	release_last_closed_stateid(oo);
	nfs4_put_stateowner(&oo->oo_owner);
}

static inline int
hash_sessionid(struct nfs4_sessionid *sessionid)
{
	struct nfsd4_sessionid *sid = (struct nfsd4_sessionid *)sessionid;

	return sid->sequence % SESSION_HASH_SIZE;
}

#ifdef CONFIG_SUNRPC_DEBUG
static inline void
dump_sessionid(const char *fn, struct nfs4_sessionid *sessionid)
{
	u32 *ptr = (u32 *)(&sessionid->data[0]);
	dprintk("%s: %u:%u:%u:%u\n", fn, ptr[0], ptr[1], ptr[2], ptr[3]);
}
#else
static inline void
dump_sessionid(const char *fn, struct nfs4_sessionid *sessionid)
{
}
#endif

/*
 * Bump the seqid on cstate->replay_owner, and clear replay_owner if it
 * won't be used for replay.
 */
void nfsd4_bump_seqid(struct nfsd4_compound_state *cstate, __be32 nfserr)
{
	struct nfs4_stateowner *so = cstate->replay_owner;

	if (nfserr == nfserr_replay_me)
		return;

	if (!seqid_mutating_err(ntohl(nfserr))) {
		nfsd4_cstate_clear_replay(cstate);
		return;
	}
	if (!so)
		return;
	if (so->so_is_open_owner)
		release_last_closed_stateid(openowner(so));
	so->so_seqid++;
	return;
}

static void
gen_sessionid(struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;
	struct nfsd4_sessionid *sid;

	sid = (struct nfsd4_sessionid *)ses->se_sessionid.data;
	sid->clientid = clp->cl_clientid;
	sid->sequence = current_sessionid++;
	sid->reserved = 0;
}

/*
 * The protocol defines ca_maxresponssize_cached to include the size of
 * the rpc header, but all we need to cache is the data starting after
 * the end of the initial SEQUENCE operation--the rest we regenerate
 * each time.  Therefore we can advertise a ca_maxresponssize_cached
 * value that is the number of bytes in our cache plus a few additional
 * bytes.  In order to stay on the safe side, and not promise more than
 * we can cache, those additional bytes must be the minimum possible: 24
 * bytes of rpc header (xid through accept state, with AUTH_NULL
 * verifier), 12 for the compound header (with zero-length tag), and 44
 * for the SEQUENCE op response:
 */
#define NFSD_MIN_HDR_SEQ_SZ  (24 + 12 + 44)

static void
free_session_slots(struct nfsd4_session *ses)
{
	int i;

	for (i = 0; i < ses->se_fchannel.maxreqs; i++) {
		free_svc_cred(&ses->se_slots[i]->sl_cred);
		kfree(ses->se_slots[i]);
	}
}

/*
 * We don't actually need to cache the rpc and session headers, so we
 * can allocate a little less for each slot:
 */
static inline u32 slot_bytes(struct nfsd4_channel_attrs *ca)
{
	u32 size;

	if (ca->maxresp_cached < NFSD_MIN_HDR_SEQ_SZ)
		size = 0;
	else
		size = ca->maxresp_cached - NFSD_MIN_HDR_SEQ_SZ;
	return size + sizeof(struct nfsd4_slot);
}

/*
 * XXX: If we run out of reserved DRC memory we could (up to a point)
 * re-negotiate active sessions and reduce their slot usage to make
 * room for new connections. For now we just fail the create session.
 */
static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn)
{
	u32 slotsize = slot_bytes(ca);
	u32 num = ca->maxreqs;
	unsigned long avail, total_avail;
	unsigned int scale_factor;

	spin_lock(&nfsd_drc_lock);
	if (nfsd_drc_max_mem > nfsd_drc_mem_used)
		total_avail = nfsd_drc_max_mem - nfsd_drc_mem_used;
	else
		/* We have handed out more space than we chose in
		 * set_max_drc() to allow.  That isn't really a
		 * problem as long as that doesn't make us think we
		 * have lots more due to integer overflow.
		 */
		total_avail = 0;
	avail = min((unsigned long)NFSD_MAX_MEM_PER_SESSION, total_avail);
	/*
	 * Never use more than a fraction of the remaining memory,
	 * unless it's the only way to give this client a slot.
	 * The chosen fraction is either 1/8 or 1/number of threads,
	 * whichever is smaller.  This ensures there are adequate
	 * slots to support multiple clients per thread.
	 * Give the client one slot even if that would require
	 * over-allocation--it is better than failure.
	 */
	scale_factor = max_t(unsigned int, 8, nn->nfsd_serv->sv_nrthreads);

	avail = clamp_t(unsigned long, avail, slotsize,
			total_avail/scale_factor);
	num = min_t(int, num, avail / slotsize);
	num = max_t(int, num, 1);
	nfsd_drc_mem_used += num * slotsize;
	spin_unlock(&nfsd_drc_lock);

	return num;
}

static void nfsd4_put_drc_mem(struct nfsd4_channel_attrs *ca)
{
	int slotsize = slot_bytes(ca);

	spin_lock(&nfsd_drc_lock);
	nfsd_drc_mem_used -= slotsize * ca->maxreqs;
	spin_unlock(&nfsd_drc_lock);
}

static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fattrs,
					   struct nfsd4_channel_attrs *battrs)
{
	int numslots = fattrs->maxreqs;
	int slotsize = slot_bytes(fattrs);
	struct nfsd4_session *new;
	int mem, i;

	BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot *)
			+ sizeof(struct nfsd4_session) > PAGE_SIZE);
	mem = numslots * sizeof(struct nfsd4_slot *);

	new = kzalloc(sizeof(*new) + mem, GFP_KERNEL);
	if (!new)
		return NULL;
	/* allocate each struct nfsd4_slot and data cache in one piece */
	for (i = 0; i < numslots; i++) {
		new->se_slots[i] = kzalloc(slotsize, GFP_KERNEL);
		if (!new->se_slots[i])
			goto out_free;
	}

	memcpy(&new->se_fchannel, fattrs, sizeof(struct nfsd4_channel_attrs));
	memcpy(&new->se_bchannel, battrs, sizeof(struct nfsd4_channel_attrs));

	return new;
out_free:
	while (i--)
		kfree(new->se_slots[i]);
	kfree(new);
	return NULL;
}

static void free_conn(struct nfsd4_conn *c)
{
	svc_xprt_put(c->cn_xprt);
	kfree(c);
}

static void nfsd4_conn_lost(struct svc_xpt_user *u)
{
	struct nfsd4_conn *c = container_of(u, struct nfsd4_conn, cn_xpt_user);
	struct nfs4_client *clp = c->cn_session->se_client;

	trace_nfsd_cb_lost(clp);

	spin_lock(&clp->cl_lock);
	if (!list_empty(&c->cn_persession)) {
		list_del(&c->cn_persession);
		free_conn(c);
	}
	nfsd4_probe_callback(clp);
	spin_unlock(&clp->cl_lock);
}

static struct nfsd4_conn *alloc_conn(struct svc_rqst *rqstp, u32 flags)
{
	struct nfsd4_conn *conn;

	conn = kmalloc(sizeof(struct nfsd4_conn), GFP_KERNEL);
	if (!conn)
		return NULL;
	svc_xprt_get(rqstp->rq_xprt);
	conn->cn_xprt = rqstp->rq_xprt;
	conn->cn_flags = flags;
	INIT_LIST_HEAD(&conn->cn_xpt_user.list);
	return conn;
}

static void __nfsd4_hash_conn(struct nfsd4_conn *conn, struct nfsd4_session *ses)
{
	conn->cn_session = ses;
	list_add(&conn->cn_persession, &ses->se_conns);
}

static void nfsd4_hash_conn(struct nfsd4_conn *conn, struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;

	spin_lock(&clp->cl_lock);
	__nfsd4_hash_conn(conn, ses);
	spin_unlock(&clp->cl_lock);
}

static int nfsd4_register_conn(struct nfsd4_conn *conn)
{
	conn->cn_xpt_user.callback = nfsd4_conn_lost;
	return register_xpt_user(conn->cn_xprt, &conn->cn_xpt_user);
}

static void nfsd4_init_conn(struct svc_rqst *rqstp, struct nfsd4_conn *conn, struct nfsd4_session *ses)
{
	int ret;

	nfsd4_hash_conn(conn, ses);
	ret = nfsd4_register_conn(conn);
	if (ret)
		/* oops; xprt is already down: */
		nfsd4_conn_lost(&conn->cn_xpt_user);
	/* We may have gained or lost a callback channel: */
	nfsd4_probe_callback_sync(ses->se_client);
}

static struct nfsd4_conn *alloc_conn_from_crses(struct svc_rqst *rqstp, struct nfsd4_create_session *cses)
{
	u32 dir = NFS4_CDFC4_FORE;

	if (cses->flags & SESSION4_BACK_CHAN)
		dir |= NFS4_CDFC4_BACK;
	return alloc_conn(rqstp, dir);
}

/* must be called under client_lock */
static void nfsd4_del_conns(struct nfsd4_session *s)
{
	struct nfs4_client *clp = s->se_client;
	struct nfsd4_conn *c;

	spin_lock(&clp->cl_lock);
	while (!list_empty(&s->se_conns)) {
		c = list_first_entry(&s->se_conns, struct nfsd4_conn, cn_persession);
		list_del_init(&c->cn_persession);
		spin_unlock(&clp->cl_lock);

		unregister_xpt_user(c->cn_xprt, &c->cn_xpt_user);
		free_conn(c);

		spin_lock(&clp->cl_lock);
	}
	spin_unlock(&clp->cl_lock);
}

static void __free_session(struct nfsd4_session *ses)
{
	free_session_slots(ses);
	kfree(ses);
}

static void free_session(struct nfsd4_session *ses)
{
	nfsd4_del_conns(ses);
	nfsd4_put_drc_mem(&ses->se_fchannel);
	__free_session(ses);
}

static void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, struct nfs4_client *clp, struct nfsd4_create_session *cses)
{
	int idx;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	new->se_client = clp;
	gen_sessionid(new);

	INIT_LIST_HEAD(&new->se_conns);

	new->se_cb_seq_nr = 1;
	new->se_flags = cses->flags;
	new->se_cb_prog = cses->callback_prog;
	new->se_cb_sec = cses->cb_sec;
	atomic_set(&new->se_ref, 0);
	idx = hash_sessionid(&new->se_sessionid);
	list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]);
	spin_lock(&clp->cl_lock);
	list_add(&new->se_perclnt, &clp->cl_sessions);
	spin_unlock(&clp->cl_lock);

	{
		struct sockaddr *sa = svc_addr(rqstp);
		/*
		 * This is a little silly; with sessions there's no real
		 * use for the callback address.  Use the peer address
		 * as a reasonable default for now, but consider fixing
		 * the rpc client not to require an address in the
		 * future:
		 */
		rpc_copy_addr((struct sockaddr *)&clp->cl_cb_conn.cb_addr, sa);
		clp->cl_cb_conn.cb_addrlen = svc_addr_len(sa);
	}
}

/* caller must hold client_lock */
static struct nfsd4_session *
__find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
{
	struct nfsd4_session *elem;
	int idx;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	dump_sessionid(__func__, sessionid);
	idx = hash_sessionid(sessionid);
	/* Search in the appropriate list */
	list_for_each_entry(elem, &nn->sessionid_hashtbl[idx], se_hash) {
		if (!memcmp(elem->se_sessionid.data, sessionid->data,
			    NFS4_MAX_SESSIONID_LEN)) {
			return elem;
		}
	}

	dprintk("%s: session not found\n", __func__);
	return NULL;
}

static struct nfsd4_session *
find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
		__be32 *ret)
{
	struct nfsd4_session *session;
	__be32 status = nfserr_badsession;

	session = __find_in_sessionid_hashtbl(sessionid, net);
	if (!session)
		goto out;
	status = nfsd4_get_session_locked(session);
	if (status)
		session = NULL;
out:
	*ret = status;
	return session;
}

/* caller must hold client_lock */
static void
unhash_session(struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	list_del(&ses->se_hash);
	spin_lock(&ses->se_client->cl_lock);
	list_del(&ses->se_perclnt);
	spin_unlock(&ses->se_client->cl_lock);
}

/* SETCLIENTID and SETCLIENTID_CONFIRM Helper functions */
static int
STALE_CLIENTID(clientid_t *clid, struct nfsd_net *nn)
{
	/*
	 * We're assuming the clid was not given out from a boot
	 * precisely 2^32 (about 136 years) before this one.  That seems
	 * a safe assumption:
	 */
	if (clid->cl_boot == (u32)nn->boot_time)
		return 0;
	trace_nfsd_clid_stale(clid);
	return 1;
}

/* 
 * XXX Should we use a slab cache ?
 * This type of memory management is somewhat inefficient, but we use it
 * anyway since SETCLIENTID is not a common operation.
 */
static struct nfs4_client *alloc_client(struct xdr_netobj name,
				struct nfsd_net *nn)
{
	struct nfs4_client *clp;
	int i;

	if (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) {
		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
		return NULL;
	}
	clp = kmem_cache_zalloc(client_slab, GFP_KERNEL);
	if (clp == NULL)
		return NULL;
	xdr_netobj_dup(&clp->cl_name, &name, GFP_KERNEL);
	if (clp->cl_name.data == NULL)
		goto err_no_name;
	clp->cl_ownerstr_hashtbl = kmalloc_array(OWNER_HASH_SIZE,
						 sizeof(struct list_head),
						 GFP_KERNEL);
	if (!clp->cl_ownerstr_hashtbl)
		goto err_no_hashtbl;
	for (i = 0; i < OWNER_HASH_SIZE; i++)
		INIT_LIST_HEAD(&clp->cl_ownerstr_hashtbl[i]);
	INIT_LIST_HEAD(&clp->cl_sessions);
	idr_init(&clp->cl_stateids);
	atomic_set(&clp->cl_rpc_users, 0);
	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
	clp->cl_state = NFSD4_ACTIVE;
	atomic_inc(&nn->nfs4_client_count);
	atomic_set(&clp->cl_delegs_in_recall, 0);
	INIT_LIST_HEAD(&clp->cl_idhash);
	INIT_LIST_HEAD(&clp->cl_openowners);
	INIT_LIST_HEAD(&clp->cl_delegations);
	INIT_LIST_HEAD(&clp->cl_lru);
	INIT_LIST_HEAD(&clp->cl_revoked);
#ifdef CONFIG_NFSD_PNFS
	INIT_LIST_HEAD(&clp->cl_lo_states);
#endif
	INIT_LIST_HEAD(&clp->async_copies);
	spin_lock_init(&clp->async_lock);
	spin_lock_init(&clp->cl_lock);
	rpc_init_wait_queue(&clp->cl_cb_waitq, "Backchannel slot table");
	return clp;
err_no_hashtbl:
	kfree(clp->cl_name.data);
err_no_name:
	kmem_cache_free(client_slab, clp);
	return NULL;
}

static void __free_client(struct kref *k)
{
	struct nfsdfs_client *c = container_of(k, struct nfsdfs_client, cl_ref);
	struct nfs4_client *clp = container_of(c, struct nfs4_client, cl_nfsdfs);

	free_svc_cred(&clp->cl_cred);
	kfree(clp->cl_ownerstr_hashtbl);
	kfree(clp->cl_name.data);
	kfree(clp->cl_nii_domain.data);
	kfree(clp->cl_nii_name.data);
	idr_destroy(&clp->cl_stateids);
	kmem_cache_free(client_slab, clp);
}

static void drop_client(struct nfs4_client *clp)
{
	kref_put(&clp->cl_nfsdfs.cl_ref, __free_client);
}

static void
free_client(struct nfs4_client *clp)
{
	while (!list_empty(&clp->cl_sessions)) {
		struct nfsd4_session *ses;
		ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
				se_perclnt);
		list_del(&ses->se_perclnt);
		WARN_ON_ONCE(atomic_read(&ses->se_ref));
		free_session(ses);
	}
	rpc_destroy_wait_queue(&clp->cl_cb_waitq);
	if (clp->cl_nfsd_dentry) {
		nfsd_client_rmdir(clp->cl_nfsd_dentry);
		clp->cl_nfsd_dentry = NULL;
		wake_up_all(&expiry_wq);
	}
	drop_client(clp);
}

/* must be called under the client_lock */
static void
unhash_client_locked(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
	struct nfsd4_session *ses;

	lockdep_assert_held(&nn->client_lock);

	/* Mark the client as expired! */
	clp->cl_time = 0;
	/* Make it invisible */
	if (!list_empty(&clp->cl_idhash)) {
		list_del_init(&clp->cl_idhash);
		if (test_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags))
			rb_erase(&clp->cl_namenode, &nn->conf_name_tree);
		else
			rb_erase(&clp->cl_namenode, &nn->unconf_name_tree);
	}
	list_del_init(&clp->cl_lru);
	spin_lock(&clp->cl_lock);
	list_for_each_entry(ses, &clp->cl_sessions, se_perclnt)
		list_del_init(&ses->se_hash);
	spin_unlock(&clp->cl_lock);
}

static void
unhash_client(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	spin_lock(&nn->client_lock);
	unhash_client_locked(clp);
	spin_unlock(&nn->client_lock);
}

static __be32 mark_client_expired_locked(struct nfs4_client *clp)
{
	if (atomic_read(&clp->cl_rpc_users))
		return nfserr_jukebox;
	unhash_client_locked(clp);
	return nfs_ok;
}

static void
__destroy_client(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
	int i;
	struct nfs4_openowner *oo;
	struct nfs4_delegation *dp;
	struct list_head reaplist;

	INIT_LIST_HEAD(&reaplist);
	spin_lock(&state_lock);
	while (!list_empty(&clp->cl_delegations)) {
		dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt);
		WARN_ON(!unhash_delegation_locked(dp));
		list_add(&dp->dl_recall_lru, &reaplist);
	}
	spin_unlock(&state_lock);
	while (!list_empty(&reaplist)) {
		dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
		list_del_init(&dp->dl_recall_lru);
		destroy_unhashed_deleg(dp);
	}
	while (!list_empty(&clp->cl_revoked)) {
		dp = list_entry(clp->cl_revoked.next, struct nfs4_delegation, dl_recall_lru);
		list_del_init(&dp->dl_recall_lru);
		nfs4_put_stid(&dp->dl_stid);
	}
	while (!list_empty(&clp->cl_openowners)) {
		oo = list_entry(clp->cl_openowners.next, struct nfs4_openowner, oo_perclient);
		nfs4_get_stateowner(&oo->oo_owner);
		release_openowner(oo);
	}
	for (i = 0; i < OWNER_HASH_SIZE; i++) {
		struct nfs4_stateowner *so, *tmp;

		list_for_each_entry_safe(so, tmp, &clp->cl_ownerstr_hashtbl[i],
					 so_strhash) {
			/* Should be no openowners at this point */
			WARN_ON_ONCE(so->so_is_open_owner);
			remove_blocked_locks(lockowner(so));
		}
	}
	nfsd4_return_all_client_layouts(clp);
	nfsd4_shutdown_copy(clp);
	nfsd4_shutdown_callback(clp);
	if (clp->cl_cb_conn.cb_xprt)
		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
	atomic_add_unless(&nn->nfs4_client_count, -1, 0);
	nfsd4_dec_courtesy_client_count(nn, clp);
	free_client(clp);
	wake_up_all(&expiry_wq);
}

static void
destroy_client(struct nfs4_client *clp)
{
	unhash_client(clp);
	__destroy_client(clp);
}

static void inc_reclaim_complete(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	if (!nn->track_reclaim_completes)
		return;
	if (!nfsd4_find_reclaim_client(clp->cl_name, nn))
		return;
	if (atomic_inc_return(&nn->nr_reclaim_complete) ==
			nn->reclaim_str_hashtbl_size) {
		printk(KERN_INFO "NFSD: all clients done reclaiming, ending NFSv4 grace period (net %x)\n",
				clp->net->ns.inum);
		nfsd4_end_grace(nn);
	}
}

static void expire_client(struct nfs4_client *clp)
{
	unhash_client(clp);
	nfsd4_client_record_remove(clp);
	__destroy_client(clp);
}

static void copy_verf(struct nfs4_client *target, nfs4_verifier *source)
{
	memcpy(target->cl_verifier.data, source->data,
			sizeof(target->cl_verifier.data));
}

static void copy_clid(struct nfs4_client *target, struct nfs4_client *source)
{
	target->cl_clientid.cl_boot = source->cl_clientid.cl_boot; 
	target->cl_clientid.cl_id = source->cl_clientid.cl_id; 
}

static int copy_cred(struct svc_cred *target, struct svc_cred *source)
{
	target->cr_principal = kstrdup(source->cr_principal, GFP_KERNEL);
	target->cr_raw_principal = kstrdup(source->cr_raw_principal,
								GFP_KERNEL);
	target->cr_targ_princ = kstrdup(source->cr_targ_princ, GFP_KERNEL);
	if ((source->cr_principal && !target->cr_principal) ||
	    (source->cr_raw_principal && !target->cr_raw_principal) ||
	    (source->cr_targ_princ && !target->cr_targ_princ))
		return -ENOMEM;

	target->cr_flavor = source->cr_flavor;
	target->cr_uid = source->cr_uid;
	target->cr_gid = source->cr_gid;
	target->cr_group_info = source->cr_group_info;
	get_group_info(target->cr_group_info);
	target->cr_gss_mech = source->cr_gss_mech;
	if (source->cr_gss_mech)
		gss_mech_get(source->cr_gss_mech);
	return 0;
}

static int
compare_blob(const struct xdr_netobj *o1, const struct xdr_netobj *o2)
{
	if (o1->len < o2->len)
		return -1;
	if (o1->len > o2->len)
		return 1;
	return memcmp(o1->data, o2->data, o1->len);
}

static int
same_verf(nfs4_verifier *v1, nfs4_verifier *v2)
{
	return 0 == memcmp(v1->data, v2->data, sizeof(v1->data));
}

static int
same_clid(clientid_t *cl1, clientid_t *cl2)
{
	return (cl1->cl_boot == cl2->cl_boot) && (cl1->cl_id == cl2->cl_id);
}

static bool groups_equal(struct group_info *g1, struct group_info *g2)
{
	int i;

	if (g1->ngroups != g2->ngroups)
		return false;
	for (i=0; i<g1->ngroups; i++)
		if (!gid_eq(g1->gid[i], g2->gid[i]))
			return false;
	return true;
}

/*
 * RFC 3530 language requires clid_inuse be returned when the
 * "principal" associated with a requests differs from that previously
 * used.  We use uid, gid's, and gss principal string as our best
 * approximation.  We also don't want to allow non-gss use of a client
 * established using gss: in theory cr_principal should catch that
 * change, but in practice cr_principal can be null even in the gss case
 * since gssd doesn't always pass down a principal string.
 */
static bool is_gss_cred(struct svc_cred *cr)
{
	/* Is cr_flavor one of the gss "pseudoflavors"?: */
	return (cr->cr_flavor > RPC_AUTH_MAXFLAVOR);
}


static bool
same_creds(struct svc_cred *cr1, struct svc_cred *cr2)
{
	if ((is_gss_cred(cr1) != is_gss_cred(cr2))
		|| (!uid_eq(cr1->cr_uid, cr2->cr_uid))
		|| (!gid_eq(cr1->cr_gid, cr2->cr_gid))
		|| !groups_equal(cr1->cr_group_info, cr2->cr_group_info))
		return false;
	/* XXX: check that cr_targ_princ fields match ? */
	if (cr1->cr_principal == cr2->cr_principal)
		return true;
	if (!cr1->cr_principal || !cr2->cr_principal)
		return false;
	return 0 == strcmp(cr1->cr_principal, cr2->cr_principal);
}

static bool svc_rqst_integrity_protected(struct svc_rqst *rqstp)
{
	struct svc_cred *cr = &rqstp->rq_cred;
	u32 service;

	if (!cr->cr_gss_mech)
		return false;
	service = gss_pseudoflavor_to_service(cr->cr_gss_mech, cr->cr_flavor);
	return service == RPC_GSS_SVC_INTEGRITY ||
	       service == RPC_GSS_SVC_PRIVACY;
}

bool nfsd4_mach_creds_match(struct nfs4_client *cl, struct svc_rqst *rqstp)
{
	struct svc_cred *cr = &rqstp->rq_cred;

	if (!cl->cl_mach_cred)
		return true;
	if (cl->cl_cred.cr_gss_mech != cr->cr_gss_mech)
		return false;
	if (!svc_rqst_integrity_protected(rqstp))
		return false;
	if (cl->cl_cred.cr_raw_principal)
		return 0 == strcmp(cl->cl_cred.cr_raw_principal,
						cr->cr_raw_principal);
	if (!cr->cr_principal)
		return false;
	return 0 == strcmp(cl->cl_cred.cr_principal, cr->cr_principal);
}

static void gen_confirm(struct nfs4_client *clp, struct nfsd_net *nn)
{
	__be32 verf[2];

	/*
	 * This is opaque to client, so no need to byte-swap. Use
	 * __force to keep sparse happy
	 */
	verf[0] = (__force __be32)(u32)ktime_get_real_seconds();
	verf[1] = (__force __be32)nn->clverifier_counter++;
	memcpy(clp->cl_confirm.data, verf, sizeof(clp->cl_confirm.data));
}

static void gen_clid(struct nfs4_client *clp, struct nfsd_net *nn)
{
	clp->cl_clientid.cl_boot = (u32)nn->boot_time;
	clp->cl_clientid.cl_id = nn->clientid_counter++;
	gen_confirm(clp, nn);
}

static struct nfs4_stid *
find_stateid_locked(struct nfs4_client *cl, stateid_t *t)
{
	struct nfs4_stid *ret;

	ret = idr_find(&cl->cl_stateids, t->si_opaque.so_id);
	if (!ret || !ret->sc_type)
		return NULL;
	return ret;
}

static struct nfs4_stid *
find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask)
{
	struct nfs4_stid *s;

	spin_lock(&cl->cl_lock);
	s = find_stateid_locked(cl, t);
	if (s != NULL) {
		if (typemask & s->sc_type)
			refcount_inc(&s->sc_count);
		else
			s = NULL;
	}
	spin_unlock(&cl->cl_lock);
	return s;
}

static struct nfs4_client *get_nfsdfs_clp(struct inode *inode)
{
	struct nfsdfs_client *nc;
	nc = get_nfsdfs_client(inode);
	if (!nc)
		return NULL;
	return container_of(nc, struct nfs4_client, cl_nfsdfs);
}

static void seq_quote_mem(struct seq_file *m, char *data, int len)
{
	seq_printf(m, "\"");
	seq_escape_mem(m, data, len, ESCAPE_HEX | ESCAPE_NAP | ESCAPE_APPEND, "\"\\");
	seq_printf(m, "\"");
}

static const char *cb_state2str(int state)
{
	switch (state) {
	case NFSD4_CB_UP:
		return "UP";
	case NFSD4_CB_UNKNOWN:
		return "UNKNOWN";
	case NFSD4_CB_DOWN:
		return "DOWN";
	case NFSD4_CB_FAULT:
		return "FAULT";
	}
	return "UNDEFINED";
}

static int client_info_show(struct seq_file *m, void *v)
{
	struct inode *inode = file_inode(m->file);
	struct nfs4_client *clp;
	u64 clid;

	clp = get_nfsdfs_clp(inode);
	if (!clp)
		return -ENXIO;
	memcpy(&clid, &clp->cl_clientid, sizeof(clid));
	seq_printf(m, "clientid: 0x%llx\n", clid);
	seq_printf(m, "address: \"%pISpc\"\n", (struct sockaddr *)&clp->cl_addr);

	if (clp->cl_state == NFSD4_COURTESY)
		seq_puts(m, "status: courtesy\n");
	else if (clp->cl_state == NFSD4_EXPIRABLE)
		seq_puts(m, "status: expirable\n");
	else if (test_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags))
		seq_puts(m, "status: confirmed\n");
	else
		seq_puts(m, "status: unconfirmed\n");
	seq_printf(m, "seconds from last renew: %lld\n",
		ktime_get_boottime_seconds() - clp->cl_time);
	seq_printf(m, "name: ");
	seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
	seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
	if (clp->cl_nii_domain.data) {
		seq_printf(m, "Implementation domain: ");
		seq_quote_mem(m, clp->cl_nii_domain.data,
					clp->cl_nii_domain.len);
		seq_printf(m, "\nImplementation name: ");
		seq_quote_mem(m, clp->cl_nii_name.data, clp->cl_nii_name.len);
		seq_printf(m, "\nImplementation time: [%lld, %ld]\n",
			clp->cl_nii_time.tv_sec, clp->cl_nii_time.tv_nsec);
	}
	seq_printf(m, "callback state: %s\n", cb_state2str(clp->cl_cb_state));
	seq_printf(m, "callback address: %pISpc\n", &clp->cl_cb_conn.cb_addr);
	drop_client(clp);

	return 0;
}

DEFINE_SHOW_ATTRIBUTE(client_info);

static void *states_start(struct seq_file *s, loff_t *pos)
	__acquires(&clp->cl_lock)
{
	struct nfs4_client *clp = s->private;
	unsigned long id = *pos;
	void *ret;

	spin_lock(&clp->cl_lock);
	ret = idr_get_next_ul(&clp->cl_stateids, &id);
	*pos = id;
	return ret;
}

static void *states_next(struct seq_file *s, void *v, loff_t *pos)
{
	struct nfs4_client *clp = s->private;
	unsigned long id = *pos;
	void *ret;

	id = *pos;
	id++;
	ret = idr_get_next_ul(&clp->cl_stateids, &id);
	*pos = id;
	return ret;
}

static void states_stop(struct seq_file *s, void *v)
	__releases(&clp->cl_lock)
{
	struct nfs4_client *clp = s->private;

	spin_unlock(&clp->cl_lock);
}

static void nfs4_show_fname(struct seq_file *s, struct nfsd_file *f)
{
         seq_printf(s, "filename: \"%pD2\"", f->nf_file);
}

static void nfs4_show_superblock(struct seq_file *s, struct nfsd_file *f)
{
	struct inode *inode = file_inode(f->nf_file);

	seq_printf(s, "superblock: \"%02x:%02x:%ld\"",
					MAJOR(inode->i_sb->s_dev),
					 MINOR(inode->i_sb->s_dev),
					 inode->i_ino);
}

static void nfs4_show_owner(struct seq_file *s, struct nfs4_stateowner *oo)
{
	seq_printf(s, "owner: ");
	seq_quote_mem(s, oo->so_owner.data, oo->so_owner.len);
}

static void nfs4_show_stateid(struct seq_file *s, stateid_t *stid)
{
	seq_printf(s, "0x%.8x", stid->si_generation);
	seq_printf(s, "%12phN", &stid->si_opaque);
}

static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st)
{
	struct nfs4_ol_stateid *ols;
	struct nfs4_file *nf;
	struct nfsd_file *file;
	struct nfs4_stateowner *oo;
	unsigned int access, deny;

	if (st->sc_type != NFS4_OPEN_STID && st->sc_type != NFS4_LOCK_STID)
		return 0; /* XXX: or SEQ_SKIP? */
	ols = openlockstateid(st);
	oo = ols->st_stateowner;
	nf = st->sc_file;

	spin_lock(&nf->fi_lock);
	file = find_any_file_locked(nf);
	if (!file)
		goto out;

	seq_printf(s, "- ");
	nfs4_show_stateid(s, &st->sc_stateid);
	seq_printf(s, ": { type: open, ");

	access = bmap_to_share_mode(ols->st_access_bmap);
	deny   = bmap_to_share_mode(ols->st_deny_bmap);

	seq_printf(s, "access: %s%s, ",
		access & NFS4_SHARE_ACCESS_READ ? "r" : "-",
		access & NFS4_SHARE_ACCESS_WRITE ? "w" : "-");
	seq_printf(s, "deny: %s%s, ",
		deny & NFS4_SHARE_ACCESS_READ ? "r" : "-",
		deny & NFS4_SHARE_ACCESS_WRITE ? "w" : "-");

	nfs4_show_superblock(s, file);
	seq_printf(s, ", ");
	nfs4_show_fname(s, file);
	seq_printf(s, ", ");
	nfs4_show_owner(s, oo);
	seq_printf(s, " }\n");
out:
	spin_unlock(&nf->fi_lock);
	return 0;
}

static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st)
{
	struct nfs4_ol_stateid *ols;
	struct nfs4_file *nf;
	struct nfsd_file *file;
	struct nfs4_stateowner *oo;

	ols = openlockstateid(st);
	oo = ols->st_stateowner;
	nf = st->sc_file;
	spin_lock(&nf->fi_lock);
	file = find_any_file_locked(nf);
	if (!file)
		goto out;

	seq_printf(s, "- ");
	nfs4_show_stateid(s, &st->sc_stateid);
	seq_printf(s, ": { type: lock, ");

	/*
	 * Note: a lock stateid isn't really the same thing as a lock,
	 * it's the locking state held by one owner on a file, and there
	 * may be multiple (or no) lock ranges associated with it.
	 * (Same for the matter is true of open stateids.)
	 */

	nfs4_show_superblock(s, file);
	/* XXX: open stateid? */
	seq_printf(s, ", ");
	nfs4_show_fname(s, file);
	seq_printf(s, ", ");
	nfs4_show_owner(s, oo);
	seq_printf(s, " }\n");
out:
	spin_unlock(&nf->fi_lock);
	return 0;
}

static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st)
{
	struct nfs4_delegation *ds;
	struct nfs4_file *nf;
	struct nfsd_file *file;

	ds = delegstateid(st);
	nf = st->sc_file;
	spin_lock(&nf->fi_lock);
	file = find_deleg_file_locked(nf);
	if (!file)
		goto out;

	seq_printf(s, "- ");
	nfs4_show_stateid(s, &st->sc_stateid);
	seq_printf(s, ": { type: deleg, ");

	/* Kinda dead code as long as we only support read delegs: */
	seq_printf(s, "access: %s, ",
		ds->dl_type == NFS4_OPEN_DELEGATE_READ ? "r" : "w");

	/* XXX: lease time, whether it's being recalled. */

	nfs4_show_superblock(s, file);
	seq_printf(s, ", ");
	nfs4_show_fname(s, file);
	seq_printf(s, " }\n");
out:
	spin_unlock(&nf->fi_lock);
	return 0;
}

static int nfs4_show_layout(struct seq_file *s, struct nfs4_stid *st)
{
	struct nfs4_layout_stateid *ls;
	struct nfsd_file *file;

	ls = container_of(st, struct nfs4_layout_stateid, ls_stid);
	file = ls->ls_file;

	seq_printf(s, "- ");
	nfs4_show_stateid(s, &st->sc_stateid);
	seq_printf(s, ": { type: layout, ");

	/* XXX: What else would be useful? */

	nfs4_show_superblock(s, file);
	seq_printf(s, ", ");
	nfs4_show_fname(s, file);
	seq_printf(s, " }\n");

	return 0;
}

static int states_show(struct seq_file *s, void *v)
{
	struct nfs4_stid *st = v;

	switch (st->sc_type) {
	case NFS4_OPEN_STID:
		return nfs4_show_open(s, st);
	case NFS4_LOCK_STID:
		return nfs4_show_lock(s, st);
	case NFS4_DELEG_STID:
		return nfs4_show_deleg(s, st);
	case NFS4_LAYOUT_STID:
		return nfs4_show_layout(s, st);
	default:
		return 0; /* XXX: or SEQ_SKIP? */
	}
	/* XXX: copy stateids? */
}

static struct seq_operations states_seq_ops = {
	.start = states_start,
	.next = states_next,
	.stop = states_stop,
	.show = states_show
};

static int client_states_open(struct inode *inode, struct file *file)
{
	struct seq_file *s;
	struct nfs4_client *clp;
	int ret;

	clp = get_nfsdfs_clp(inode);
	if (!clp)
		return -ENXIO;

	ret = seq_open(file, &states_seq_ops);
	if (ret)
		return ret;
	s = file->private_data;
	s->private = clp;
	return 0;
}

static int client_opens_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = file->private_data;
	struct nfs4_client *clp = m->private;

	/* XXX: alternatively, we could get/drop in seq start/stop */
	drop_client(clp);
	return 0;
}

static const struct file_operations client_states_fops = {
	.open		= client_states_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= client_opens_release,
};

/*
 * Normally we refuse to destroy clients that are in use, but here the
 * administrator is telling us to just do it.  We also want to wait
 * so the caller has a guarantee that the client's locks are gone by
 * the time the write returns:
 */
static void force_expire_client(struct nfs4_client *clp)
{
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
	bool already_expired;

	trace_nfsd_clid_admin_expired(&clp->cl_clientid);

	spin_lock(&nn->client_lock);
	clp->cl_time = 0;
	spin_unlock(&nn->client_lock);

	wait_event(expiry_wq, atomic_read(&clp->cl_rpc_users) == 0);
	spin_lock(&nn->client_lock);
	already_expired = list_empty(&clp->cl_lru);
	if (!already_expired)
		unhash_client_locked(clp);
	spin_unlock(&nn->client_lock);

	if (!already_expired)
		expire_client(clp);
	else
		wait_event(expiry_wq, clp->cl_nfsd_dentry == NULL);
}

static ssize_t client_ctl_write(struct file *file, const char __user *buf,
				   size_t size, loff_t *pos)
{
	char *data;
	struct nfs4_client *clp;

	data = simple_transaction_get(file, buf, size);
	if (IS_ERR(data))
		return PTR_ERR(data);
	if (size != 7 || 0 != memcmp(data, "expire\n", 7))
		return -EINVAL;
	clp = get_nfsdfs_clp(file_inode(file));
	if (!clp)
		return -ENXIO;
	force_expire_client(clp);
	drop_client(clp);
	return 7;
}

static const struct file_operations client_ctl_fops = {
	.write		= client_ctl_write,
	.release	= simple_transaction_release,
};

static const struct tree_descr client_files[] = {
	[0] = {"info", &client_info_fops, S_IRUSR},
	[1] = {"states", &client_states_fops, S_IRUSR},
	[2] = {"ctl", &client_ctl_fops, S_IWUSR},
	[3] = {""},
};

static struct nfs4_client *create_client(struct xdr_netobj name,
		struct svc_rqst *rqstp, nfs4_verifier *verf)
{
	struct nfs4_client *clp;
	struct sockaddr *sa = svc_addr(rqstp);
	int ret;
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	struct dentry *dentries[ARRAY_SIZE(client_files)];

	clp = alloc_client(name, nn);
	if (clp == NULL)
		return NULL;

	ret = copy_cred(&clp->cl_cred, &rqstp->rq_cred);
	if (ret) {
		free_client(clp);
		return NULL;
	}
	gen_clid(clp, nn);
	kref_init(&clp->cl_nfsdfs.cl_ref);
	nfsd4_init_cb(&clp->cl_cb_null, clp, NULL, NFSPROC4_CLNT_CB_NULL);
	clp->cl_time = ktime_get_boottime_seconds();
	clear_bit(0, &clp->cl_cb_slot_busy);
	copy_verf(clp, verf);
	memcpy(&clp->cl_addr, sa, sizeof(struct sockaddr_storage));
	clp->cl_cb_session = NULL;
	clp->net = net;
	clp->cl_nfsd_dentry = nfsd_client_mkdir(
		nn, &clp->cl_nfsdfs,
		clp->cl_clientid.cl_id - nn->clientid_base,
		client_files, dentries);
	clp->cl_nfsd_info_dentry = dentries[0];
	if (!clp->cl_nfsd_dentry) {
		free_client(clp);
		return NULL;
	}
	return clp;
}

static void
add_clp_to_name_tree(struct nfs4_client *new_clp, struct rb_root *root)
{
	struct rb_node **new = &(root->rb_node), *parent = NULL;
	struct nfs4_client *clp;

	while (*new) {
		clp = rb_entry(*new, struct nfs4_client, cl_namenode);
		parent = *new;

		if (compare_blob(&clp->cl_name, &new_clp->cl_name) > 0)
			new = &((*new)->rb_left);
		else
			new = &((*new)->rb_right);
	}

	rb_link_node(&new_clp->cl_namenode, parent, new);
	rb_insert_color(&new_clp->cl_namenode, root);
}

static struct nfs4_client *
find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
{
	int cmp;
	struct rb_node *node = root->rb_node;
	struct nfs4_client *clp;

	while (node) {
		clp = rb_entry(node, struct nfs4_client, cl_namenode);
		cmp = compare_blob(&clp->cl_name, name);
		if (cmp > 0)
			node = node->rb_left;
		else if (cmp < 0)
			node = node->rb_right;
		else
			return clp;
	}
	return NULL;
}

static void
add_to_unconfirmed(struct nfs4_client *clp)
{
	unsigned int idhashval;
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	clear_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags);
	add_clp_to_name_tree(clp, &nn->unconf_name_tree);
	idhashval = clientid_hashval(clp->cl_clientid.cl_id);
	list_add(&clp->cl_idhash, &nn->unconf_id_hashtbl[idhashval]);
	renew_client_locked(clp);
}

static void
move_to_confirmed(struct nfs4_client *clp)
{
	unsigned int idhashval = clientid_hashval(clp->cl_clientid.cl_id);
	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);

	lockdep_assert_held(&nn->client_lock);

	list_move(&clp->cl_idhash, &nn->conf_id_hashtbl[idhashval]);
	rb_erase(&clp->cl_namenode, &nn->unconf_name_tree);
	add_clp_to_name_tree(clp, &nn->conf_name_tree);
	set_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags);
	trace_nfsd_clid_confirmed(&clp->cl_clientid);
	renew_client_locked(clp);
}

static struct nfs4_client *
find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
{
	struct nfs4_client *clp;
	unsigned int idhashval = clientid_hashval(clid->cl_id);

	list_for_each_entry(clp, &tbl[idhashval], cl_idhash) {
		if (same_clid(&clp->cl_clientid, clid)) {
			if ((bool)clp->cl_minorversion != sessions)
				return NULL;
			renew_client_locked(clp);
			return clp;
		}
	}
	return NULL;
}

static struct nfs4_client *
find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
{
	struct list_head *tbl = nn->conf_id_hashtbl;

	lockdep_assert_held(&nn->client_lock);
	return find_client_in_id_table(tbl, clid, sessions);
}

static struct nfs4_client *
find_unconfirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
{
	struct list_head *tbl = nn->unconf_id_hashtbl;

	lockdep_assert_held(&nn->client_lock);
	return find_client_in_id_table(tbl, clid, sessions);
}

static bool clp_used_exchangeid(struct nfs4_client *clp)
{
	return clp->cl_exchange_flags != 0;
} 

static struct nfs4_client *
find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
{
	lockdep_assert_held(&nn->client_lock);
	return find_clp_in_name_tree(name, &nn->conf_name_tree);
}

static struct nfs4_client *
find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
{
	lockdep_assert_held(&nn->client_lock);
	return find_clp_in_name_tree(name, &nn->unconf_name_tree);
}

static void
gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, struct svc_rqst *rqstp)
{
	struct nfs4_cb_conn *conn = &clp->cl_cb_conn;
	struct sockaddr	*sa = svc_addr(rqstp);
	u32 scopeid = rpc_get_scope_id(sa);
	unsigned short expected_family;

	/* Currently, we only support tcp and tcp6 for the callback channel */
	if (se->se_callback_netid_len == 3 &&
	    !memcmp(se->se_callback_netid_val, "tcp", 3))
		expected_family = AF_INET;
	else if (se->se_callback_netid_len == 4 &&
		 !memcmp(se->se_callback_netid_val, "tcp6", 4))
		expected_family = AF_INET6;
	else
		goto out_err;

	conn->cb_addrlen = rpc_uaddr2sockaddr(clp->net, se->se_callback_addr_val,
					    se->se_callback_addr_len,
					    (struct sockaddr *)&conn->cb_addr,
					    sizeof(conn->cb_addr));

	if (!conn->cb_addrlen || conn->cb_addr.ss_family != expected_family)
		goto out_err;

	if (conn->cb_addr.ss_family == AF_INET6)
		((struct sockaddr_in6 *)&conn->cb_addr)->sin6_scope_id = scopeid;

	conn->cb_prog = se->se_callback_prog;
	conn->cb_ident = se->se_callback_ident;
	memcpy(&conn->cb_saddr, &rqstp->rq_daddr, rqstp->rq_daddrlen);
	trace_nfsd_cb_args(clp, conn);
	return;
out_err:
	conn->cb_addr.ss_family = AF_UNSPEC;
	conn->cb_addrlen = 0;
	trace_nfsd_cb_nodelegs(clp);
	return;
}

/*
 * Cache a reply. nfsd4_check_resp_size() has bounded the cache size.
 */
static void
nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
{
	struct xdr_buf *buf = resp->xdr->buf;
	struct nfsd4_slot *slot = resp->cstate.slot;
	unsigned int base;

	dprintk("--> %s slot %p\n", __func__, slot);

	slot->sl_flags |= NFSD4_SLOT_INITIALIZED;
	slot->sl_opcnt = resp->opcnt;
	slot->sl_status = resp->cstate.status;
	free_svc_cred(&slot->sl_cred);
	copy_cred(&slot->sl_cred, &resp->rqstp->rq_cred);

	if (!nfsd4_cache_this(resp)) {
		slot->sl_flags &= ~NFSD4_SLOT_CACHED;
		return;
	}
	slot->sl_flags |= NFSD4_SLOT_CACHED;

	base = resp->cstate.data_offset;
	slot->sl_datalen = buf->len - base;
	if (read_bytes_from_xdr_buf(buf, base, slot->sl_data, slot->sl_datalen))
		WARN(1, "%s: sessions DRC could not cache compound\n",
		     __func__);
	return;
}

/*
 * Encode the replay sequence operation from the slot values.
 * If cachethis is FALSE encode the uncached rep error on the next
 * operation which sets resp->p and increments resp->opcnt for
 * nfs4svc_encode_compoundres.
 *
 */
static __be32
nfsd4_enc_sequence_replay(struct nfsd4_compoundargs *args,
			  struct nfsd4_compoundres *resp)
{
	struct nfsd4_op *op;
	struct nfsd4_slot *slot = resp->cstate.slot;

	/* Encode the replayed sequence operation */
	op = &args->ops[resp->opcnt - 1];
	nfsd4_encode_operation(resp, op);

	if (slot->sl_flags & NFSD4_SLOT_CACHED)
		return op->status;
	if (args->opcnt == 1) {
		/*
		 * The original operation wasn't a solo sequence--we
		 * always cache those--so this retry must not match the
		 * original:
		 */
		op->status = nfserr_seq_false_retry;
	} else {
		op = &args->ops[resp->opcnt++];
		op->status = nfserr_retry_uncached_rep;
		nfsd4_encode_operation(resp, op);
	}
	return op->status;
}

/*
 * The sequence operation is not cached because we can use the slot and
 * session values.
 */
static __be32
nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
			 struct nfsd4_sequence *seq)
{
	struct nfsd4_slot *slot = resp->cstate.slot;
	struct xdr_stream *xdr = resp->xdr;
	__be32 *p;
	__be32 status;

	dprintk("--> %s slot %p\n", __func__, slot);

	status = nfsd4_enc_sequence_replay(resp->rqstp->rq_argp, resp);
	if (status)
		return status;

	p = xdr_reserve_space(xdr, slot->sl_datalen);
	if (!p) {
		WARN_ON_ONCE(1);
		return nfserr_serverfault;
	}
	xdr_encode_opaque_fixed(p, slot->sl_data, slot->sl_datalen);
	xdr_commit_encode(xdr);

	resp->opcnt = slot->sl_opcnt;
	return slot->sl_status;
}

/*
 * Set the exchange_id flags returned by the server.
 */
static void
nfsd4_set_ex_flags(struct nfs4_client *new, struct nfsd4_exchange_id *clid)
{
#ifdef CONFIG_NFSD_PNFS
	new->cl_exchange_flags |= EXCHGID4_FLAG_USE_PNFS_MDS;
#else
	new->cl_exchange_flags |= EXCHGID4_FLAG_USE_NON_PNFS;
#endif

	/* Referrals are supported, Migration is not. */
	new->cl_exchange_flags |= EXCHGID4_FLAG_SUPP_MOVED_REFER;

	/* set the wire flags to return to client. */
	clid->flags = new->cl_exchange_flags;
}

static bool client_has_openowners(struct nfs4_client *clp)
{
	struct nfs4_openowner *oo;

	list_for_each_entry(oo, &clp->cl_openowners, oo_perclient) {
		if (!list_empty(&oo->oo_owner.so_stateids))
			return true;
	}
	return false;
}

static bool client_has_state(struct nfs4_client *clp)
{
	return client_has_openowners(clp)
#ifdef CONFIG_NFSD_PNFS
		|| !list_empty(&clp->cl_lo_states)
#endif
		|| !list_empty(&clp->cl_delegations)
		|| !list_empty(&clp->cl_sessions)
		|| !list_empty(&clp->async_copies);
}

static __be32 copy_impl_id(struct nfs4_client *clp,
				struct nfsd4_exchange_id *exid)
{
	if (!exid->nii_domain.data)
		return 0;
	xdr_netobj_dup(&clp->cl_nii_domain, &exid->nii_domain, GFP_KERNEL);
	if (!clp->cl_nii_domain.data)
		return nfserr_jukebox;
	xdr_netobj_dup(&clp->cl_nii_name, &exid->nii_name, GFP_KERNEL);
	if (!clp->cl_nii_name.data)
		return nfserr_jukebox;
	clp->cl_nii_time = exid->nii_time;
	return 0;
}

__be32
nfsd4_exchange_id(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfsd4_exchange_id *exid = &u->exchange_id;
	struct nfs4_client *conf, *new;
	struct nfs4_client *unconf = NULL;
	__be32 status;
	char			addr_str[INET6_ADDRSTRLEN];
	nfs4_verifier		verf = exid->verifier;
	struct sockaddr		*sa = svc_addr(rqstp);
	bool	update = exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A;
	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	rpc_ntop(sa, addr_str, sizeof(addr_str));
	dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
		"ip_addr=%s flags %x, spa_how %u\n",
		__func__, rqstp, exid, exid->clname.len, exid->clname.data,
		addr_str, exid->flags, exid->spa_how);

	if (exid->flags & ~EXCHGID4_FLAG_MASK_A)
		return nfserr_inval;

	new = create_client(exid->clname, rqstp, &verf);
	if (new == NULL)
		return nfserr_jukebox;
	status = copy_impl_id(new, exid);
	if (status)
		goto out_nolock;

	switch (exid->spa_how) {
	case SP4_MACH_CRED:
		exid->spo_must_enforce[0] = 0;
		exid->spo_must_enforce[1] = (
			1 << (OP_BIND_CONN_TO_SESSION - 32) |
			1 << (OP_EXCHANGE_ID - 32) |
			1 << (OP_CREATE_SESSION - 32) |
			1 << (OP_DESTROY_SESSION - 32) |
			1 << (OP_DESTROY_CLIENTID - 32));

		exid->spo_must_allow[0] &= (1 << (OP_CLOSE) |
					1 << (OP_OPEN_DOWNGRADE) |
					1 << (OP_LOCKU) |
					1 << (OP_DELEGRETURN));

		exid->spo_must_allow[1] &= (
					1 << (OP_TEST_STATEID - 32) |
					1 << (OP_FREE_STATEID - 32));
		if (!svc_rqst_integrity_protected(rqstp)) {
			status = nfserr_inval;
			goto out_nolock;
		}
		/*
		 * Sometimes userspace doesn't give us a principal.
		 * Which is a bug, really.  Anyway, we can't enforce
		 * MACH_CRED in that case, better to give up now:
		 */
		if (!new->cl_cred.cr_principal &&
					!new->cl_cred.cr_raw_principal) {
			status = nfserr_serverfault;
			goto out_nolock;
		}
		new->cl_mach_cred = true;
		break;
	case SP4_NONE:
		break;
	default:				/* checked by xdr code */
		WARN_ON_ONCE(1);
		fallthrough;
	case SP4_SSV:
		status = nfserr_encr_alg_unsupp;
		goto out_nolock;
	}

	/* Cases below refer to rfc 5661 section 18.35.4: */
	spin_lock(&nn->client_lock);
	conf = find_confirmed_client_by_name(&exid->clname, nn);
	if (conf) {
		bool creds_match = same_creds(&conf->cl_cred, &rqstp->rq_cred);
		bool verfs_match = same_verf(&verf, &conf->cl_verifier);

		if (update) {
			if (!clp_used_exchangeid(conf)) { /* buggy client */
				status = nfserr_inval;
				goto out;
			}
			if (!nfsd4_mach_creds_match(conf, rqstp)) {
				status = nfserr_wrong_cred;
				goto out;
			}
			if (!creds_match) { /* case 9 */
				status = nfserr_perm;
				goto out;
			}
			if (!verfs_match) { /* case 8 */
				status = nfserr_not_same;
				goto out;
			}
			/* case 6 */
			exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
			trace_nfsd_clid_confirmed_r(conf);
			goto out_copy;
		}
		if (!creds_match) { /* case 3 */
			if (client_has_state(conf)) {
				status = nfserr_clid_inuse;
				trace_nfsd_clid_cred_mismatch(conf, rqstp);
				goto out;
			}
			goto out_new;
		}
		if (verfs_match) { /* case 2 */
			conf->cl_exchange_flags |= EXCHGID4_FLAG_CONFIRMED_R;
			trace_nfsd_clid_confirmed_r(conf);
			goto out_copy;
		}
		/* case 5, client reboot */
		trace_nfsd_clid_verf_mismatch(conf, rqstp, &verf);
		conf = NULL;
		goto out_new;
	}

	if (update) { /* case 7 */
		status = nfserr_noent;
		goto out;
	}

	unconf = find_unconfirmed_client_by_name(&exid->clname, nn);
	if (unconf) /* case 4, possible retry or client restart */
		unhash_client_locked(unconf);

	/* case 1, new owner ID */
	trace_nfsd_clid_fresh(new);

out_new:
	if (conf) {
		status = mark_client_expired_locked(conf);
		if (status)
			goto out;
		trace_nfsd_clid_replaced(&conf->cl_clientid);
	}
	new->cl_minorversion = cstate->minorversion;
	new->cl_spo_must_allow.u.words[0] = exid->spo_must_allow[0];
	new->cl_spo_must_allow.u.words[1] = exid->spo_must_allow[1];

	add_to_unconfirmed(new);
	swap(new, conf);
out_copy:
	exid->clientid.cl_boot = conf->cl_clientid.cl_boot;
	exid->clientid.cl_id = conf->cl_clientid.cl_id;

	exid->seqid = conf->cl_cs_slot.sl_seqid + 1;
	nfsd4_set_ex_flags(conf, exid);

	dprintk("nfsd4_exchange_id seqid %d flags %x\n",
		conf->cl_cs_slot.sl_seqid, conf->cl_exchange_flags);
	status = nfs_ok;

out:
	spin_unlock(&nn->client_lock);
out_nolock:
	if (new)
		expire_client(new);
	if (unconf) {
		trace_nfsd_clid_expire_unconf(&unconf->cl_clientid);
		expire_client(unconf);
	}
	return status;
}

static __be32
check_slot_seqid(u32 seqid, u32 slot_seqid, int slot_inuse)
{
	dprintk("%s enter. seqid %d slot_seqid %d\n", __func__, seqid,
		slot_seqid);

	/* The slot is in use, and no response has been sent. */
	if (slot_inuse) {
		if (seqid == slot_seqid)
			return nfserr_jukebox;
		else
			return nfserr_seq_misordered;
	}
	/* Note unsigned 32-bit arithmetic handles wraparound: */
	if (likely(seqid == slot_seqid + 1))
		return nfs_ok;
	if (seqid == slot_seqid)
		return nfserr_replay_cache;
	return nfserr_seq_misordered;
}

/*
 * Cache the create session result into the create session single DRC
 * slot cache by saving the xdr structure. sl_seqid has been set.
 * Do this for solo or embedded create session operations.
 */
static void
nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
			   struct nfsd4_clid_slot *slot, __be32 nfserr)
{
	slot->sl_status = nfserr;
	memcpy(&slot->sl_cr_ses, cr_ses, sizeof(*cr_ses));
}

static __be32
nfsd4_replay_create_session(struct nfsd4_create_session *cr_ses,
			    struct nfsd4_clid_slot *slot)
{
	memcpy(cr_ses, &slot->sl_cr_ses, sizeof(*cr_ses));
	return slot->sl_status;
}

#define NFSD_MIN_REQ_HDR_SEQ_SZ	((\
			2 * 2 + /* credential,verifier: AUTH_NULL, length 0 */ \
			1 +	/* MIN tag is length with zero, only length */ \
			3 +	/* version, opcount, opcode */ \
			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
				/* seqid, slotID, slotID, cache */ \
			4 ) * sizeof(__be32))

#define NFSD_MIN_RESP_HDR_SEQ_SZ ((\
			2 +	/* verifier: AUTH_NULL, length 0 */\
			1 +	/* status */ \
			1 +	/* MIN tag is length with zero, only length */ \
			3 +	/* opcount, opcode, opstatus*/ \
			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
				/* seqid, slotID, slotID, slotID, status */ \
			5 ) * sizeof(__be32))

static __be32 check_forechannel_attrs(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn)
{
	u32 maxrpc = nn->nfsd_serv->sv_max_mesg;

	if (ca->maxreq_sz < NFSD_MIN_REQ_HDR_SEQ_SZ)
		return nfserr_toosmall;
	if (ca->maxresp_sz < NFSD_MIN_RESP_HDR_SEQ_SZ)
		return nfserr_toosmall;
	ca->headerpadsz = 0;
	ca->maxreq_sz = min_t(u32, ca->maxreq_sz, maxrpc);
	ca->maxresp_sz = min_t(u32, ca->maxresp_sz, maxrpc);
	ca->maxops = min_t(u32, ca->maxops, NFSD_MAX_OPS_PER_COMPOUND);
	ca->maxresp_cached = min_t(u32, ca->maxresp_cached,
			NFSD_SLOT_CACHE_SIZE + NFSD_MIN_HDR_SEQ_SZ);
	ca->maxreqs = min_t(u32, ca->maxreqs, NFSD_MAX_SLOTS_PER_SESSION);
	/*
	 * Note decreasing slot size below client's request may make it
	 * difficult for client to function correctly, whereas
	 * decreasing the number of slots will (just?) affect
	 * performance.  When short on memory we therefore prefer to
	 * decrease number of slots instead of their size.  Clients that
	 * request larger slots than they need will get poor results:
	 * Note that we always allow at least one slot, because our
	 * accounting is soft and provides no guarantees either way.
	 */
	ca->maxreqs = nfsd4_get_drc_mem(ca, nn);

	return nfs_ok;
}

/*
 * Server's NFSv4.1 backchannel support is AUTH_SYS-only for now.
 * These are based on similar macros in linux/sunrpc/msg_prot.h .
 */
#define RPC_MAX_HEADER_WITH_AUTH_SYS \
	(RPC_CALLHDRSIZE + 2 * (2 + UNX_CALLSLACK))

#define RPC_MAX_REPHEADER_WITH_AUTH_SYS \
	(RPC_REPHDRSIZE + (2 + NUL_REPLYSLACK))

#define NFSD_CB_MAX_REQ_SZ	((NFS4_enc_cb_recall_sz + \
				 RPC_MAX_HEADER_WITH_AUTH_SYS) * sizeof(__be32))
#define NFSD_CB_MAX_RESP_SZ	((NFS4_dec_cb_recall_sz + \
				 RPC_MAX_REPHEADER_WITH_AUTH_SYS) * \
				 sizeof(__be32))

static __be32 check_backchannel_attrs(struct nfsd4_channel_attrs *ca)
{
	ca->headerpadsz = 0;

	if (ca->maxreq_sz < NFSD_CB_MAX_REQ_SZ)
		return nfserr_toosmall;
	if (ca->maxresp_sz < NFSD_CB_MAX_RESP_SZ)
		return nfserr_toosmall;
	ca->maxresp_cached = 0;
	if (ca->maxops < 2)
		return nfserr_toosmall;

	return nfs_ok;
}

static __be32 nfsd4_check_cb_sec(struct nfsd4_cb_sec *cbs)
{
	switch (cbs->flavor) {
	case RPC_AUTH_NULL:
	case RPC_AUTH_UNIX:
		return nfs_ok;
	default:
		/*
		 * GSS case: the spec doesn't allow us to return this
		 * error.  But it also doesn't allow us not to support
		 * GSS.
		 * I'd rather this fail hard than return some error the
		 * client might think it can already handle:
		 */
		return nfserr_encr_alg_unsupp;
	}
}

__be32
nfsd4_create_session(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
	struct nfsd4_create_session *cr_ses = &u->create_session;
	struct sockaddr *sa = svc_addr(rqstp);
	struct nfs4_client *conf, *unconf;
	struct nfs4_client *old = NULL;
	struct nfsd4_session *new;
	struct nfsd4_conn *conn;
	struct nfsd4_clid_slot *cs_slot = NULL;
	__be32 status = 0;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	if (cr_ses->flags & ~SESSION4_FLAG_MASK_A)
		return nfserr_inval;
	status = nfsd4_check_cb_sec(&cr_ses->cb_sec);
	if (status)
		return status;
	status = check_forechannel_attrs(&cr_ses->fore_channel, nn);
	if (status)
		return status;
	status = check_backchannel_attrs(&cr_ses->back_channel);
	if (status)
		goto out_release_drc_mem;
	status = nfserr_jukebox;
	new = alloc_session(&cr_ses->fore_channel, &cr_ses->back_channel);
	if (!new)
		goto out_release_drc_mem;
	conn = alloc_conn_from_crses(rqstp, cr_ses);
	if (!conn)
		goto out_free_session;

	spin_lock(&nn->client_lock);
	unconf = find_unconfirmed_client(&cr_ses->clientid, true, nn);
	conf = find_confirmed_client(&cr_ses->clientid, true, nn);
	WARN_ON_ONCE(conf && unconf);

	if (conf) {
		status = nfserr_wrong_cred;
		if (!nfsd4_mach_creds_match(conf, rqstp))
			goto out_free_conn;
		cs_slot = &conf->cl_cs_slot;
		status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
		if (status) {
			if (status == nfserr_replay_cache)
				status = nfsd4_replay_create_session(cr_ses, cs_slot);
			goto out_free_conn;
		}
	} else if (unconf) {
		status = nfserr_clid_inuse;
		if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
		    !rpc_cmp_addr(sa, (struct sockaddr *) &unconf->cl_addr)) {
			trace_nfsd_clid_cred_mismatch(unconf, rqstp);
			goto out_free_conn;
		}
		status = nfserr_wrong_cred;
		if (!nfsd4_mach_creds_match(unconf, rqstp))
			goto out_free_conn;
		cs_slot = &unconf->cl_cs_slot;
		status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
		if (status) {
			/* an unconfirmed replay returns misordered */
			status = nfserr_seq_misordered;
			goto out_free_conn;
		}
		old = find_confirmed_client_by_name(&unconf->cl_name, nn);
		if (old) {
			status = mark_client_expired_locked(old);
			if (status) {
				old = NULL;
				goto out_free_conn;
			}
			trace_nfsd_clid_replaced(&old->cl_clientid);
		}
		move_to_confirmed(unconf);
		conf = unconf;
	} else {
		status = nfserr_stale_clientid;
		goto out_free_conn;
	}
	status = nfs_ok;
	/* Persistent sessions are not supported */
	cr_ses->flags &= ~SESSION4_PERSIST;
	/* Upshifting from TCP to RDMA is not supported */
	cr_ses->flags &= ~SESSION4_RDMA;

	init_session(rqstp, new, conf, cr_ses);
	nfsd4_get_session_locked(new);

	memcpy(cr_ses->sessionid.data, new->se_sessionid.data,
	       NFS4_MAX_SESSIONID_LEN);
	cs_slot->sl_seqid++;
	cr_ses->seqid = cs_slot->sl_seqid;

	/* cache solo and embedded create sessions under the client_lock */
	nfsd4_cache_create_session(cr_ses, cs_slot, status);
	spin_unlock(&nn->client_lock);
	if (conf == unconf)
		fsnotify_dentry(conf->cl_nfsd_info_dentry, FS_MODIFY);
	/* init connection and backchannel */
	nfsd4_init_conn(rqstp, conn, new);
	nfsd4_put_session(new);
	if (old)
		expire_client(old);
	return status;
out_free_conn:
	spin_unlock(&nn->client_lock);
	free_conn(conn);
	if (old)
		expire_client(old);
out_free_session:
	__free_session(new);
out_release_drc_mem:
	nfsd4_put_drc_mem(&cr_ses->fore_channel);
	return status;
}

static __be32 nfsd4_map_bcts_dir(u32 *dir)
{
	switch (*dir) {
	case NFS4_CDFC4_FORE:
	case NFS4_CDFC4_BACK:
		return nfs_ok;
	case NFS4_CDFC4_FORE_OR_BOTH:
	case NFS4_CDFC4_BACK_OR_BOTH:
		*dir = NFS4_CDFC4_BOTH;
		return nfs_ok;
	}
	return nfserr_inval;
}

__be32 nfsd4_backchannel_ctl(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfsd4_backchannel_ctl *bc = &u->backchannel_ctl;
	struct nfsd4_session *session = cstate->session;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
	__be32 status;

	status = nfsd4_check_cb_sec(&bc->bc_cb_sec);
	if (status)
		return status;
	spin_lock(&nn->client_lock);
	session->se_cb_prog = bc->bc_cb_program;
	session->se_cb_sec = bc->bc_cb_sec;
	spin_unlock(&nn->client_lock);

	nfsd4_probe_callback(session->se_client);

	return nfs_ok;
}

static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_session *s)
{
	struct nfsd4_conn *c;

	list_for_each_entry(c, &s->se_conns, cn_persession) {
		if (c->cn_xprt == xpt) {
			return c;
		}
	}
	return NULL;
}

static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
		struct nfsd4_session *session, u32 req, struct nfsd4_conn **conn)
{
	struct nfs4_client *clp = session->se_client;
	struct svc_xprt *xpt = rqst->rq_xprt;
	struct nfsd4_conn *c;
	__be32 status;

	/* Following the last paragraph of RFC 5661 Section 18.34.3: */
	spin_lock(&clp->cl_lock);
	c = __nfsd4_find_conn(xpt, session);
	if (!c)
		status = nfserr_noent;
	else if (req == c->cn_flags)
		status = nfs_ok;
	else if (req == NFS4_CDFC4_FORE_OR_BOTH &&
				c->cn_flags != NFS4_CDFC4_BACK)
		status = nfs_ok;
	else if (req == NFS4_CDFC4_BACK_OR_BOTH &&
				c->cn_flags != NFS4_CDFC4_FORE)
		status = nfs_ok;
	else
		status = nfserr_inval;
	spin_unlock(&clp->cl_lock);
	if (status == nfs_ok && conn)
		*conn = c;
	return status;
}

__be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
		     struct nfsd4_compound_state *cstate,
		     union nfsd4_op_u *u)
{
	struct nfsd4_bind_conn_to_session *bcts = &u->bind_conn_to_session;
	__be32 status;
	struct nfsd4_conn *conn;
	struct nfsd4_session *session;
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	if (!nfsd4_last_compound_op(rqstp))
		return nfserr_not_only_op;
	spin_lock(&nn->client_lock);
	session = find_in_sessionid_hashtbl(&bcts->sessionid, net, &status);
	spin_unlock(&nn->client_lock);
	if (!session)
		goto out_no_session;
	status = nfserr_wrong_cred;
	if (!nfsd4_mach_creds_match(session->se_client, rqstp))
		goto out;
	status = nfsd4_match_existing_connection(rqstp, session,
			bcts->dir, &conn);
	if (status == nfs_ok) {
		if (bcts->dir == NFS4_CDFC4_FORE_OR_BOTH ||
				bcts->dir == NFS4_CDFC4_BACK)
			conn->cn_flags |= NFS4_CDFC4_BACK;
		nfsd4_probe_callback(session->se_client);
		goto out;
	}
	if (status == nfserr_inval)
		goto out;
	status = nfsd4_map_bcts_dir(&bcts->dir);
	if (status)
		goto out;
	conn = alloc_conn(rqstp, bcts->dir);
	status = nfserr_jukebox;
	if (!conn)
		goto out;
	nfsd4_init_conn(rqstp, conn, session);
	status = nfs_ok;
out:
	nfsd4_put_session(session);
out_no_session:
	return status;
}

static bool nfsd4_compound_in_session(struct nfsd4_compound_state *cstate, struct nfs4_sessionid *sid)
{
	if (!cstate->session)
		return false;
	return !memcmp(sid, &cstate->session->se_sessionid, sizeof(*sid));
}

__be32
nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfs4_sessionid *sessionid = &u->destroy_session.sessionid;
	struct nfsd4_session *ses;
	__be32 status;
	int ref_held_by_me = 0;
	struct net *net = SVC_NET(r);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	status = nfserr_not_only_op;
	if (nfsd4_compound_in_session(cstate, sessionid)) {
		if (!nfsd4_last_compound_op(r))
			goto out;
		ref_held_by_me++;
	}
	dump_sessionid(__func__, sessionid);
	spin_lock(&nn->client_lock);
	ses = find_in_sessionid_hashtbl(sessionid, net, &status);
	if (!ses)
		goto out_client_lock;
	status = nfserr_wrong_cred;
	if (!nfsd4_mach_creds_match(ses->se_client, r))
		goto out_put_session;
	status = mark_session_dead_locked(ses, 1 + ref_held_by_me);
	if (status)
		goto out_put_session;
	unhash_session(ses);
	spin_unlock(&nn->client_lock);

	nfsd4_probe_callback_sync(ses->se_client);

	spin_lock(&nn->client_lock);
	status = nfs_ok;
out_put_session:
	nfsd4_put_session_locked(ses);
out_client_lock:
	spin_unlock(&nn->client_lock);
out:
	return status;
}

static __be32 nfsd4_sequence_check_conn(struct nfsd4_conn *new, struct nfsd4_session *ses)
{
	struct nfs4_client *clp = ses->se_client;
	struct nfsd4_conn *c;
	__be32 status = nfs_ok;
	int ret;

	spin_lock(&clp->cl_lock);
	c = __nfsd4_find_conn(new->cn_xprt, ses);
	if (c)
		goto out_free;
	status = nfserr_conn_not_bound_to_session;
	if (clp->cl_mach_cred)
		goto out_free;
	__nfsd4_hash_conn(new, ses);
	spin_unlock(&clp->cl_lock);
	ret = nfsd4_register_conn(new);
	if (ret)
		/* oops; xprt is already down: */
		nfsd4_conn_lost(&new->cn_xpt_user);
	return nfs_ok;
out_free:
	spin_unlock(&clp->cl_lock);
	free_conn(new);
	return status;
}

static bool nfsd4_session_too_many_ops(struct svc_rqst *rqstp, struct nfsd4_session *session)
{
	struct nfsd4_compoundargs *args = rqstp->rq_argp;

	return args->opcnt > session->se_fchannel.maxops;
}

static bool nfsd4_request_too_big(struct svc_rqst *rqstp,
				  struct nfsd4_session *session)
{
	struct xdr_buf *xb = &rqstp->rq_arg;

	return xb->len > session->se_fchannel.maxreq_sz;
}

static bool replay_matches_cache(struct svc_rqst *rqstp,
		 struct nfsd4_sequence *seq, struct nfsd4_slot *slot)
{
	struct nfsd4_compoundargs *argp = rqstp->rq_argp;

	if ((bool)(slot->sl_flags & NFSD4_SLOT_CACHETHIS) !=
	    (bool)seq->cachethis)
		return false;
	/*
	 * If there's an error then the reply can have fewer ops than
	 * the call.
	 */
	if (slot->sl_opcnt < argp->opcnt && !slot->sl_status)
		return false;
	/*
	 * But if we cached a reply with *more* ops than the call you're
	 * sending us now, then this new call is clearly not really a
	 * replay of the old one:
	 */
	if (slot->sl_opcnt > argp->opcnt)
		return false;
	/* This is the only check explicitly called by spec: */
	if (!same_creds(&rqstp->rq_cred, &slot->sl_cred))
		return false;
	/*
	 * There may be more comparisons we could actually do, but the
	 * spec doesn't require us to catch every case where the calls
	 * don't match (that would require caching the call as well as
	 * the reply), so we don't bother.
	 */
	return true;
}

__be32
nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfsd4_sequence *seq = &u->sequence;
	struct nfsd4_compoundres *resp = rqstp->rq_resp;
	struct xdr_stream *xdr = resp->xdr;
	struct nfsd4_session *session;
	struct nfs4_client *clp;
	struct nfsd4_slot *slot;
	struct nfsd4_conn *conn;
	__be32 status;
	int buflen;
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	if (resp->opcnt != 1)
		return nfserr_sequence_pos;

	/*
	 * Will be either used or freed by nfsd4_sequence_check_conn
	 * below.
	 */
	conn = alloc_conn(rqstp, NFS4_CDFC4_FORE);
	if (!conn)
		return nfserr_jukebox;

	spin_lock(&nn->client_lock);
	session = find_in_sessionid_hashtbl(&seq->sessionid, net, &status);
	if (!session)
		goto out_no_session;
	clp = session->se_client;

	status = nfserr_too_many_ops;
	if (nfsd4_session_too_many_ops(rqstp, session))
		goto out_put_session;

	status = nfserr_req_too_big;
	if (nfsd4_request_too_big(rqstp, session))
		goto out_put_session;

	status = nfserr_badslot;
	if (seq->slotid >= session->se_fchannel.maxreqs)
		goto out_put_session;

	slot = session->se_slots[seq->slotid];
	dprintk("%s: slotid %d\n", __func__, seq->slotid);

	/* We do not negotiate the number of slots yet, so set the
	 * maxslots to the session maxreqs which is used to encode
	 * sr_highest_slotid and the sr_target_slot id to maxslots */
	seq->maxslots = session->se_fchannel.maxreqs;

	status = check_slot_seqid(seq->seqid, slot->sl_seqid,
					slot->sl_flags & NFSD4_SLOT_INUSE);
	if (status == nfserr_replay_cache) {
		status = nfserr_seq_misordered;
		if (!(slot->sl_flags & NFSD4_SLOT_INITIALIZED))
			goto out_put_session;
		status = nfserr_seq_false_retry;
		if (!replay_matches_cache(rqstp, seq, slot))
			goto out_put_session;
		cstate->slot = slot;
		cstate->session = session;
		cstate->clp = clp;
		/* Return the cached reply status and set cstate->status
		 * for nfsd4_proc_compound processing */
		status = nfsd4_replay_cache_entry(resp, seq);
		cstate->status = nfserr_replay_cache;
		goto out;
	}
	if (status)
		goto out_put_session;

	status = nfsd4_sequence_check_conn(conn, session);
	conn = NULL;
	if (status)
		goto out_put_session;

	buflen = (seq->cachethis) ?
			session->se_fchannel.maxresp_cached :
			session->se_fchannel.maxresp_sz;
	status = (seq->cachethis) ? nfserr_rep_too_big_to_cache :
				    nfserr_rep_too_big;
	if (xdr_restrict_buflen(xdr, buflen - rqstp->rq_auth_slack))
		goto out_put_session;
	svc_reserve(rqstp, buflen);

	status = nfs_ok;
	/* Success! bump slot seqid */
	slot->sl_seqid = seq->seqid;
	slot->sl_flags |= NFSD4_SLOT_INUSE;
	if (seq->cachethis)
		slot->sl_flags |= NFSD4_SLOT_CACHETHIS;
	else
		slot->sl_flags &= ~NFSD4_SLOT_CACHETHIS;

	cstate->slot = slot;
	cstate->session = session;
	cstate->clp = clp;

out:
	switch (clp->cl_cb_state) {
	case NFSD4_CB_DOWN:
		seq->status_flags = SEQ4_STATUS_CB_PATH_DOWN;
		break;
	case NFSD4_CB_FAULT:
		seq->status_flags = SEQ4_STATUS_BACKCHANNEL_FAULT;
		break;
	default:
		seq->status_flags = 0;
	}
	if (!list_empty(&clp->cl_revoked))
		seq->status_flags |= SEQ4_STATUS_RECALLABLE_STATE_REVOKED;
out_no_session:
	if (conn)
		free_conn(conn);
	spin_unlock(&nn->client_lock);
	return status;
out_put_session:
	nfsd4_put_session_locked(session);
	goto out_no_session;
}

void
nfsd4_sequence_done(struct nfsd4_compoundres *resp)
{
	struct nfsd4_compound_state *cs = &resp->cstate;

	if (nfsd4_has_session(cs)) {
		if (cs->status != nfserr_replay_cache) {
			nfsd4_store_cache_entry(resp);
			cs->slot->sl_flags &= ~NFSD4_SLOT_INUSE;
		}
		/* Drop session reference that was taken in nfsd4_sequence() */
		nfsd4_put_session(cs->session);
	} else if (cs->clp)
		put_client_renew(cs->clp);
}

__be32
nfsd4_destroy_clientid(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfsd4_destroy_clientid *dc = &u->destroy_clientid;
	struct nfs4_client *conf, *unconf;
	struct nfs4_client *clp = NULL;
	__be32 status = 0;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	spin_lock(&nn->client_lock);
	unconf = find_unconfirmed_client(&dc->clientid, true, nn);
	conf = find_confirmed_client(&dc->clientid, true, nn);
	WARN_ON_ONCE(conf && unconf);

	if (conf) {
		if (client_has_state(conf)) {
			status = nfserr_clientid_busy;
			goto out;
		}
		status = mark_client_expired_locked(conf);
		if (status)
			goto out;
		clp = conf;
	} else if (unconf)
		clp = unconf;
	else {
		status = nfserr_stale_clientid;
		goto out;
	}
	if (!nfsd4_mach_creds_match(clp, rqstp)) {
		clp = NULL;
		status = nfserr_wrong_cred;
		goto out;
	}
	trace_nfsd_clid_destroyed(&clp->cl_clientid);
	unhash_client_locked(clp);
out:
	spin_unlock(&nn->client_lock);
	if (clp)
		expire_client(clp);
	return status;
}

__be32
nfsd4_reclaim_complete(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
	struct nfsd4_reclaim_complete *rc = &u->reclaim_complete;
	struct nfs4_client *clp = cstate->clp;
	__be32 status = 0;

	if (rc->rca_one_fs) {
		if (!cstate->current_fh.fh_dentry)
			return nfserr_nofilehandle;
		/*
		 * We don't take advantage of the rca_one_fs case.
		 * That's OK, it's optional, we can safely ignore it.
		 */
		return nfs_ok;
	}

	status = nfserr_complete_already;
	if (test_and_set_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags))
		goto out;

	status = nfserr_stale_clientid;
	if (is_client_expired(clp))
		/*
		 * The following error isn't really legal.
		 * But we only get here if the client just explicitly
		 * destroyed the client.  Surely it no longer cares what
		 * error it gets back on an operation for the dead
		 * client.
		 */
		goto out;

	status = nfs_ok;
	trace_nfsd_clid_reclaim_complete(&clp->cl_clientid);
	nfsd4_client_record_create(clp);
	inc_reclaim_complete(clp);
out:
	return status;
}

__be32
nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		  union nfsd4_op_u *u)
{
	struct nfsd4_setclientid *setclid = &u->setclientid;
	struct xdr_netobj 	clname = setclid->se_name;
	nfs4_verifier		clverifier = setclid->se_verf;
	struct nfs4_client	*conf, *new;
	struct nfs4_client	*unconf = NULL;
	__be32 			status;
	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	new = create_client(clname, rqstp, &clverifier);
	if (new == NULL)
		return nfserr_jukebox;
	spin_lock(&nn->client_lock);
	conf = find_confirmed_client_by_name(&clname, nn);
	if (conf && client_has_state(conf)) {
		status = nfserr_clid_inuse;
		if (clp_used_exchangeid(conf))
			goto out;
		if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
			trace_nfsd_clid_cred_mismatch(conf, rqstp);
			goto out;
		}
	}
	unconf = find_unconfirmed_client_by_name(&clname, nn);
	if (unconf)
		unhash_client_locked(unconf);
	if (conf) {
		if (same_verf(&conf->cl_verifier, &clverifier)) {
			copy_clid(new, conf);
			gen_confirm(new, nn);
		} else
			trace_nfsd_clid_verf_mismatch(conf, rqstp,
						      &clverifier);
	} else
		trace_nfsd_clid_fresh(new);
	new->cl_minorversion = 0;
	gen_callback(new, setclid, rqstp);
	add_to_unconfirmed(new);
	setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
	setclid->se_clientid.cl_id = new->cl_clientid.cl_id;
	memcpy(setclid->se_confirm.data, new->cl_confirm.data, sizeof(setclid->se_confirm.data));
	new = NULL;
	status = nfs_ok;
out:
	spin_unlock(&nn->client_lock);
	if (new)
		free_client(new);
	if (unconf) {
		trace_nfsd_clid_expire_unconf(&unconf->cl_clientid);
		expire_client(unconf);
	}
	return status;
}

__be32
nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
			struct nfsd4_compound_state *cstate,
			union nfsd4_op_u *u)
{
	struct nfsd4_setclientid_confirm *setclientid_confirm =
			&u->setclientid_confirm;
	struct nfs4_client *conf, *unconf;
	struct nfs4_client *old = NULL;
	nfs4_verifier confirm = setclientid_confirm->sc_confirm; 
	clientid_t * clid = &setclientid_confirm->sc_clientid;
	__be32 status;
	struct nfsd_net	*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	if (STALE_CLIENTID(clid, nn))
		return nfserr_stale_clientid;

	spin_lock(&nn->client_lock);
	conf = find_confirmed_client(clid, false, nn);
	unconf = find_unconfirmed_client(clid, false, nn);
	/*
	 * We try hard to give out unique clientid's, so if we get an
	 * attempt to confirm the same clientid with a different cred,
	 * the client may be buggy; this should never happen.
	 *
	 * Nevertheless, RFC 7530 recommends INUSE for this case:
	 */
	status = nfserr_clid_inuse;
	if (unconf && !same_creds(&unconf->cl_cred, &rqstp->rq_cred)) {
		trace_nfsd_clid_cred_mismatch(unconf, rqstp);
		goto out;
	}
	if (conf && !same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
		trace_nfsd_clid_cred_mismatch(conf, rqstp);
		goto out;
	}
	if (!unconf || !same_verf(&confirm, &unconf->cl_confirm)) {
		if (conf && same_verf(&confirm, &conf->cl_confirm)) {
			status = nfs_ok;
		} else
			status = nfserr_stale_clientid;
		goto out;
	}
	status = nfs_ok;
	if (conf) {
		old = unconf;
		unhash_client_locked(old);
		nfsd4_change_callback(conf, &unconf->cl_cb_conn);
	} else {
		old = find_confirmed_client_by_name(&unconf->cl_name, nn);
		if (old) {
			status = nfserr_clid_inuse;
			if (client_has_state(old)
					&& !same_creds(&unconf->cl_cred,
							&old->cl_cred)) {
				old = NULL;
				goto out;
			}
			status = mark_client_expired_locked(old);
			if (status) {
				old = NULL;
				goto out;
			}
			trace_nfsd_clid_replaced(&old->cl_clientid);
		}
		move_to_confirmed(unconf);
		conf = unconf;
	}
	get_client_locked(conf);
	spin_unlock(&nn->client_lock);
	if (conf == unconf)
		fsnotify_dentry(conf->cl_nfsd_info_dentry, FS_MODIFY);
	nfsd4_probe_callback(conf);
	spin_lock(&nn->client_lock);
	put_client_renew_locked(conf);
out:
	spin_unlock(&nn->client_lock);
	if (old)
		expire_client(old);
	return status;
}

static struct nfs4_file *nfsd4_alloc_file(void)
{
	return kmem_cache_alloc(file_slab, GFP_KERNEL);
}

/* OPEN Share state helper functions */
static void nfsd4_init_file(struct svc_fh *fh, unsigned int hashval,
				struct nfs4_file *fp)
{
	lockdep_assert_held(&state_lock);

	refcount_set(&fp->fi_ref, 1);
	spin_lock_init(&fp->fi_lock);
	INIT_LIST_HEAD(&fp->fi_stateids);
	INIT_LIST_HEAD(&fp->fi_delegations);
	INIT_LIST_HEAD(&fp->fi_clnt_odstate);
	fh_copy_shallow(&fp->fi_fhandle, &fh->fh_handle);
	fp->fi_deleg_file = NULL;
	fp->fi_had_conflict = false;
	fp->fi_share_deny = 0;
	memset(fp->fi_fds, 0, sizeof(fp->fi_fds));
	memset(fp->fi_access, 0, sizeof(fp->fi_access));
	fp->fi_aliased = false;
	fp->fi_inode = d_inode(fh->fh_dentry);
#ifdef CONFIG_NFSD_PNFS
	INIT_LIST_HEAD(&fp->fi_lo_states);
	atomic_set(&fp->fi_lo_recalls, 0);
#endif
	hlist_add_head_rcu(&fp->fi_hash, &file_hashtbl[hashval]);
}

void
nfsd4_free_slabs(void)
{
	kmem_cache_destroy(client_slab);
	kmem_cache_destroy(openowner_slab);
	kmem_cache_destroy(lockowner_slab);
	kmem_cache_destroy(file_slab);
	kmem_cache_destroy(stateid_slab);
	kmem_cache_destroy(deleg_slab);
	kmem_cache_destroy(odstate_slab);
}

int
nfsd4_init_slabs(void)
{
	client_slab = kmem_cache_create("nfsd4_clients",
			sizeof(struct nfs4_client), 0, 0, NULL);
	if (client_slab == NULL)
		goto out;
	openowner_slab = kmem_cache_create("nfsd4_openowners",
			sizeof(struct nfs4_openowner), 0, 0, NULL);
	if (openowner_slab == NULL)
		goto out_free_client_slab;
	lockowner_slab = kmem_cache_create("nfsd4_lockowners",
			sizeof(struct nfs4_lockowner), 0, 0, NULL);
	if (lockowner_slab == NULL)
		goto out_free_openowner_slab;
	file_slab = kmem_cache_create("nfsd4_files",
			sizeof(struct nfs4_file), 0, 0, NULL);
	if (file_slab == NULL)
		goto out_free_lockowner_slab;
	stateid_slab = kmem_cache_create("nfsd4_stateids",
			sizeof(struct nfs4_ol_stateid), 0, 0, NULL);
	if (stateid_slab == NULL)
		goto out_free_file_slab;
	deleg_slab = kmem_cache_create("nfsd4_delegations",
			sizeof(struct nfs4_delegation), 0, 0, NULL);
	if (deleg_slab == NULL)
		goto out_free_stateid_slab;
	odstate_slab = kmem_cache_create("nfsd4_odstate",
			sizeof(struct nfs4_clnt_odstate), 0, 0, NULL);
	if (odstate_slab == NULL)
		goto out_free_deleg_slab;
	return 0;

out_free_deleg_slab:
	kmem_cache_destroy(deleg_slab);
out_free_stateid_slab:
	kmem_cache_destroy(stateid_slab);
out_free_file_slab:
	kmem_cache_destroy(file_slab);
out_free_lockowner_slab:
	kmem_cache_destroy(lockowner_slab);
out_free_openowner_slab:
	kmem_cache_destroy(openowner_slab);
out_free_client_slab:
	kmem_cache_destroy(client_slab);
out:
	return -ENOMEM;
}

static unsigned long
nfsd_courtesy_client_count(struct shrinker *shrink, struct shrink_control *sc)
{
	int cnt;
	struct nfsd_net *nn = container_of(shrink,
			struct nfsd_net, nfsd_client_shrinker);

	cnt = atomic_read(&nn->nfsd_courtesy_clients);
	if (cnt > 0)
		mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0);
	return (unsigned long)cnt;
}

static unsigned long
nfsd_courtesy_client_scan(struct shrinker *shrink, struct shrink_control *sc)
{
	return SHRINK_STOP;
}

int
nfsd4_init_leases_net(struct nfsd_net *nn)
{
	struct sysinfo si;
	u64 max_clients;

	nn->nfsd4_lease = 90;	/* default lease time */
	nn->nfsd4_grace = 90;
	nn->somebody_reclaimed = false;
	nn->track_reclaim_completes = false;
	nn->clverifier_counter = get_random_u32();
	nn->clientid_base = get_random_u32();
	nn->clientid_counter = nn->clientid_base + 1;
	nn->s2s_cp_cl_id = nn->clientid_counter++;

	atomic_set(&nn->nfs4_client_count, 0);
	si_meminfo(&si);
	max_clients = (u64)si.totalram * si.mem_unit / (1024 * 1024 * 1024);
	max_clients *= NFS4_CLIENTS_PER_GB;
	nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB);

	atomic_set(&nn->nfsd_courtesy_clients, 0);
	nn->nfsd_client_shrinker.scan_objects = nfsd_courtesy_client_scan;
	nn->nfsd_client_shrinker.count_objects = nfsd_courtesy_client_count;
	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
	return register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client");
}

void
nfsd4_leases_net_shutdown(struct nfsd_net *nn)
{
	unregister_shrinker(&nn->nfsd_client_shrinker);
}

static void init_nfs4_replay(struct nfs4_replay *rp)
{
	rp->rp_status = nfserr_serverfault;
	rp->rp_buflen = 0;
	rp->rp_buf = rp->rp_ibuf;
	mutex_init(&rp->rp_mutex);
}

static void nfsd4_cstate_assign_replay(struct nfsd4_compound_state *cstate,
		struct nfs4_stateowner *so)
{
	if (!nfsd4_has_session(cstate)) {
		mutex_lock(&so->so_replay.rp_mutex);
		cstate->replay_owner = nfs4_get_stateowner(so);
	}
}

void nfsd4_cstate_clear_replay(struct nfsd4_compound_state *cstate)
{
	struct nfs4_stateowner *so = cstate->replay_owner;

	if (so != NULL) {
		cstate->replay_owner = NULL;
		mutex_unlock(&so->so_replay.rp_mutex);
		nfs4_put_stateowner(so);
	}
}

static inline void *alloc_stateowner(struct kmem_cache *slab, struct xdr_netobj *owner, struct nfs4_client *clp)
{
	struct nfs4_stateowner *sop;

	sop = kmem_cache_alloc(slab, GFP_KERNEL);
	if (!sop)
		return NULL;

	xdr_netobj_dup(&sop->so_owner, owner, GFP_KERNEL);
	if (!sop->so_owner.data) {
		kmem_cache_free(slab, sop);
		return NULL;
	}

	INIT_LIST_HEAD(&sop->so_stateids);
	sop->so_client = clp;
	init_nfs4_replay(&sop->so_replay);
	atomic_set(&sop->so_count, 1);
	return sop;
}

static void hash_openowner(struct nfs4_openowner *oo, struct nfs4_client *clp, unsigned int strhashval)
{
	lockdep_assert_held(&clp->cl_lock);

	list_add(&oo->oo_owner.so_strhash,
		 &clp->cl_ownerstr_hashtbl[strhashval]);
	list_add(&oo->oo_perclient, &clp->cl_openowners);
}

static void nfs4_unhash_openowner(struct nfs4_stateowner *so)
{
	unhash_openowner_locked(openowner(so));
}

static void nfs4_free_openowner(struct nfs4_stateowner *so)
{
	struct nfs4_openowner *oo = openowner(so);

	kmem_cache_free(openowner_slab, oo);
}

static const struct nfs4_stateowner_operations openowner_ops = {
	.so_unhash =	nfs4_unhash_openowner,
	.so_free =	nfs4_free_openowner,
};

static struct nfs4_ol_stateid *
nfsd4_find_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
{
	struct nfs4_ol_stateid *local, *ret = NULL;
	struct nfs4_openowner *oo = open->op_openowner;

	lockdep_assert_held(&fp->fi_lock);

	list_for_each_entry(local, &fp->fi_stateids, st_perfile) {
		/* ignore lock owners */
		if (local->st_stateowner->so_is_open_owner == 0)
			continue;
		if (local->st_stateowner != &oo->oo_owner)
			continue;
		if (local->st_stid.sc_type == NFS4_OPEN_STID) {
			ret = local;
			refcount_inc(&ret->st_stid.sc_count);
			break;
		}
	}
	return ret;
}

static __be32
nfsd4_verify_open_stid(struct nfs4_stid *s)
{
	__be32 ret = nfs_ok;

	switch (s->sc_type) {
	default:
		break;
	case 0:
	case NFS4_CLOSED_STID:
	case NFS4_CLOSED_DELEG_STID:
		ret = nfserr_bad_stateid;
		break;
	case NFS4_REVOKED_DELEG_STID:
		ret = nfserr_deleg_revoked;
	}
	return ret;
}

/* Lock the stateid st_mutex, and deal with races with CLOSE */
static __be32
nfsd4_lock_ol_stateid(struct nfs4_ol_stateid *stp)
{
	__be32 ret;

	mutex_lock_nested(&stp->st_mutex, LOCK_STATEID_MUTEX);
	ret = nfsd4_verify_open_stid(&stp->st_stid);
	if (ret != nfs_ok)
		mutex_unlock(&stp->st_mutex);
	return ret;
}

static struct nfs4_ol_stateid *
nfsd4_find_and_lock_existing_open(struct nfs4_file *fp, struct nfsd4_open *open)
{
	struct nfs4_ol_stateid *stp;
	for (;;) {
		spin_lock(&fp->fi_lock);
		stp = nfsd4_find_existing_open(fp, open);
		spin_unlock(&fp->fi_lock);
		if (!stp || nfsd4_lock_ol_stateid(stp) == nfs_ok)
			break;
		nfs4_put_stid(&stp->st_stid);
	}
	return stp;
}

static struct nfs4_openowner *
alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
			   struct nfsd4_compound_state *cstate)
{
	struct nfs4_client *clp = cstate->clp;
	struct nfs4_openowner *oo, *ret;

	oo = alloc_stateowner(openowner_slab, &open->op_owner, clp);
	if (!oo)
		return NULL;
	oo->oo_owner.so_ops = &openowner_ops;
	oo->oo_owner.so_is_open_owner = 1;
	oo->oo_owner.so_seqid = open->op_seqid;
	oo->oo_flags = 0;
	if (nfsd4_has_session(cstate))
		oo->oo_flags |= NFS4_OO_CONFIRMED;
	oo->oo_time = 0;
	oo->oo_last_closed_stid = NULL;
	INIT_LIST_HEAD(&oo->oo_close_lru);
	spin_lock(&clp->cl_lock);
	ret = find_openstateowner_str_locked(strhashval, open, clp);
	if (ret == NULL) {
		hash_openowner(oo, clp, strhashval);
		ret = oo;
	} else
		nfs4_free_stateowner(&oo->oo_owner);

	spin_unlock(&clp->cl_lock);
	return ret;
}

static struct nfs4_ol_stateid *
init_open_stateid(struct nfs4_file *fp, struct nfsd4_open *open)
{

	struct nfs4_openowner *oo = open->op_openowner;
	struct nfs4_ol_stateid *retstp = NULL;
	struct nfs4_ol_stateid *stp;

	stp = open->op_stp;
	/* We are moving these outside of the spinlocks to avoid the warnings */
	mutex_init(&stp->st_mutex);
	mutex_lock_nested(&stp->st_mutex, OPEN_STATEID_MUTEX);

retry:
	spin_lock(&oo->oo_owner.so_client->cl_lock);
	spin_lock(&fp->fi_lock);

	retstp = nfsd4_find_existing_open(fp, open);
	if (retstp)
		goto out_unlock;

	open->op_stp = NULL;
	refcount_inc(&stp->st_stid.sc_count);
	stp->st_stid.sc_type = NFS4_OPEN_STID;
	INIT_LIST_HEAD(&stp->st_locks);
	stp->st_stateowner = nfs4_get_stateowner(&oo->oo_owner);
	get_nfs4_file(fp);
	stp->st_stid.sc_file = fp;
	stp->st_access_bmap = 0;
	stp->st_deny_bmap = 0;
	stp->st_openstp = NULL;
	list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids);
	list_add(&stp->st_perfile, &fp->fi_stateids);

out_unlock:
	spin_unlock(&fp->fi_lock);
	spin_unlock(&oo->oo_owner.so_client->cl_lock);
	if (retstp) {
		/* Handle races with CLOSE */
		if (nfsd4_lock_ol_stateid(retstp) != nfs_ok) {
			nfs4_put_stid(&retstp->st_stid);
			goto retry;
		}
		/* To keep mutex tracking happy */
		mutex_unlock(&stp->st_mutex);
		stp = retstp;
	}
	return stp;
}

/*
 * In the 4.0 case we need to keep the owners around a little while to handle
 * CLOSE replay. We still do need to release any file access that is held by
 * them before returning however.
 */
static void
move_to_close_lru(struct nfs4_ol_stateid *s, struct net *net)
{
	struct nfs4_ol_stateid *last;
	struct nfs4_openowner *oo = openowner(s->st_stateowner);
	struct nfsd_net *nn = net_generic(s->st_stid.sc_client->net,
						nfsd_net_id);

	dprintk("NFSD: move_to_close_lru nfs4_openowner %p\n", oo);

	/*
	 * We know that we hold one reference via nfsd4_close, and another
	 * "persistent" reference for the client. If the refcount is higher
	 * than 2, then there are still calls in progress that are using this
	 * stateid. We can't put the sc_file reference until they are finished.
	 * Wait for the refcount to drop to 2. Since it has been unhashed,
	 * there should be no danger of the refcount going back up again at
	 * this point.
	 */
	wait_event(close_wq, refcount_read(&s->st_stid.sc_count) == 2);

	release_all_access(s);
	if (s->st_stid.sc_file) {
		put_nfs4_file(s->st_stid.sc_file);
		s->st_stid.sc_file = NULL;
	}

	spin_lock(&nn->client_lock);
	last = oo->oo_last_closed_stid;
	oo->oo_last_closed_stid = s;
	list_move_tail(&oo->oo_close_lru, &nn->close_lru);
	oo->oo_time = ktime_get_boottime_seconds();
	spin_unlock(&nn->client_lock);
	if (last)
		nfs4_put_stid(&last->st_stid);
}

/* search file_hashtbl[] for file */
static struct nfs4_file *
find_file_locked(struct svc_fh *fh, unsigned int hashval)
{
	struct nfs4_file *fp;

	hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
				lockdep_is_held(&state_lock)) {
		if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
			if (refcount_inc_not_zero(&fp->fi_ref))
				return fp;
		}
	}
	return NULL;
}

static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh,
				     unsigned int hashval)
{
	struct nfs4_file *fp;
	struct nfs4_file *ret = NULL;
	bool alias_found = false;

	spin_lock(&state_lock);
	hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
				 lockdep_is_held(&state_lock)) {
		if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
			if (refcount_inc_not_zero(&fp->fi_ref))
				ret = fp;
		} else if (d_inode(fh->fh_dentry) == fp->fi_inode)
			fp->fi_aliased = alias_found = true;
	}
	if (likely(ret == NULL)) {
		nfsd4_init_file(fh, hashval, new);
		new->fi_aliased = alias_found;
		ret = new;
	}
	spin_unlock(&state_lock);
	return ret;
}

static struct nfs4_file * find_file(struct svc_fh *fh)
{
	struct nfs4_file *fp;
	unsigned int hashval = file_hashval(fh);

	rcu_read_lock();
	fp = find_file_locked(fh, hashval);
	rcu_read_unlock();
	return fp;
}

static struct nfs4_file *
find_or_add_file(struct nfs4_file *new, struct svc_fh *fh)
{
	struct nfs4_file *fp;
	unsigned int hashval = file_hashval(fh);

	rcu_read_lock();
	fp = find_file_locked(fh, hashval);
	rcu_read_unlock();
	if (fp)
		return fp;

	return insert_file(new, fh, hashval);
}

/*
 * Called to check deny when READ with all zero stateid or
 * WRITE with all zero or all one stateid
 */
static __be32
nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
{
	struct nfs4_file *fp;
	__be32 ret = nfs_ok;

	fp = find_file(current_fh);
	if (!fp)
		return ret;
	/* Check for conflicting share reservations */
	spin_lock(&fp->fi_lock);
	if (fp->fi_share_deny & deny_type)
		ret = nfserr_locked;
	spin_unlock(&fp->fi_lock);
	put_nfs4_file(fp);
	return ret;
}

static bool nfsd4_deleg_present(const struct inode *inode)
{
	struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx);

	return ctx && !list_empty_careful(&ctx->flc_lease);
}

/**
 * nfsd_wait_for_delegreturn - wait for delegations to be returned
 * @rqstp: the RPC transaction being executed
 * @inode: in-core inode of the file being waited for
 *
 * The timeout prevents deadlock if all nfsd threads happen to be
 * tied up waiting for returning delegations.
 *
 * Return values:
 *   %true: delegation was returned
 *   %false: timed out waiting for delegreturn
 */
bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode)
{
	long __maybe_unused timeo;

	timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode),
				       NFSD_DELEGRETURN_TIMEOUT);
	trace_nfsd_delegret_wakeup(rqstp, inode, timeo);
	return timeo > 0;
}

static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb)
{
	struct nfs4_delegation *dp = cb_to_delegation(cb);
	struct nfsd_net *nn = net_generic(dp->dl_stid.sc_client->net,
					  nfsd_net_id);

	block_delegations(&dp->dl_stid.sc_file->fi_fhandle);

	/*
	 * We can't do this in nfsd_break_deleg_cb because it is
	 * already holding inode->i_lock.
	 *
	 * If the dl_time != 0, then we know that it has already been
	 * queued for a lease break. Don't queue it again.
	 */
	spin_lock(&state_lock);
	if (delegation_hashed(dp) && dp->dl_time == 0) {
		dp->dl_time = ktime_get_boottime_seconds();
		list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru);
	}
	spin_unlock(&state_lock);
}

static int nfsd4_cb_recall_done(struct nfsd4_callback *cb,
		struct rpc_task *task)
{
	struct nfs4_delegation *dp = cb_to_delegation(cb);

	trace_nfsd_cb_recall_done(&dp->dl_stid.sc_stateid, task);

	if (dp->dl_stid.sc_type == NFS4_CLOSED_DELEG_STID ||
	    dp->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID)
	        return 1;

	switch (task->tk_status) {
	case 0:
		return 1;
	case -NFS4ERR_DELAY:
		rpc_delay(task, 2 * HZ);
		return 0;
	case -EBADHANDLE:
	case -NFS4ERR_BAD_STATEID:
		/*
		 * Race: client probably got cb_recall before open reply
		 * granting delegation.
		 */
		if (dp->dl_retries--) {
			rpc_delay(task, 2 * HZ);
			return 0;
		}
		fallthrough;
	default:
		return 1;
	}
}

static void nfsd4_cb_recall_release(struct nfsd4_callback *cb)
{
	struct nfs4_delegation *dp = cb_to_delegation(cb);

	nfs4_put_stid(&dp->dl_stid);
}

static const struct nfsd4_callback_ops nfsd4_cb_recall_ops = {
	.prepare	= nfsd4_cb_recall_prepare,
	.done		= nfsd4_cb_recall_done,
	.release	= nfsd4_cb_recall_release,
};

static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
{
	/*
	 * We're assuming the state code never drops its reference
	 * without first removing the lease.  Since we're in this lease
	 * callback (and since the lease code is serialized by the
	 * flc_lock) we know the server hasn't removed the lease yet, and
	 * we know it's safe to take a reference.
	 */
	refcount_inc(&dp->dl_stid.sc_count);
	WARN_ON_ONCE(!nfsd4_run_cb(&dp->dl_recall));
}

/* Called from break_lease() with flc_lock held. */
static bool
nfsd_break_deleg_cb(struct file_lock *fl)
{
	struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
	struct nfs4_file *fp = dp->dl_stid.sc_file;
	struct nfs4_client *clp = dp->dl_stid.sc_client;
	struct nfsd_net *nn;

	trace_nfsd_cb_recall(&dp->dl_stid);

	dp->dl_recalled = true;
	atomic_inc(&clp->cl_delegs_in_recall);
	if (try_to_expire_client(clp)) {
		nn = net_generic(clp->net, nfsd_net_id);
		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
	}

	/*
	 * We don't want the locks code to timeout the lease for us;
	 * we'll remove it ourself if a delegation isn't returned
	 * in time:
	 */
	fl->fl_break_time = 0;

	spin_lock(&fp->fi_lock);
	fp->fi_had_conflict = true;
	nfsd_break_one_deleg(dp);
	spin_unlock(&fp->fi_lock);
	return false;
}

/**
 * nfsd_breaker_owns_lease - Check if lease conflict was resolved
 * @fl: Lock state to check
 *
 * Return values:
 *   %true: Lease conflict was resolved
 *   %false: Lease conflict was not resolved.
 */
static bool nfsd_breaker_owns_lease(struct file_lock *fl)
{
	struct nfs4_delegation *dl = fl->fl_owner;
	struct svc_rqst *rqst;
	struct nfs4_client *clp;

	if (!i_am_nfsd())
		return false;
	rqst = kthread_data(current);
	/* Note rq_prog == NFS_ACL_PROGRAM is also possible: */
	if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
		return false;
	clp = *(rqst->rq_lease_breaker);
	return dl->dl_stid.sc_client == clp;
}

static int
nfsd_change_deleg_cb(struct file_lock *onlist, int arg,
		     struct list_head *dispose)
{
	struct nfs4_delegation *dp = (struct nfs4_delegation *)onlist->fl_owner;
	struct nfs4_client *clp = dp->dl_stid.sc_client;

	if (arg & F_UNLCK) {
		if (dp->dl_recalled)
			atomic_dec(&clp->cl_delegs_in_recall);
		return lease_modify(onlist, arg, dispose);
	} else
		return -EAGAIN;
}

static const struct lock_manager_operations nfsd_lease_mng_ops = {
	.lm_breaker_owns_lease = nfsd_breaker_owns_lease,
	.lm_break = nfsd_break_deleg_cb,
	.lm_change = nfsd_change_deleg_cb,
};

static __be32 nfsd4_check_seqid(struct nfsd4_compound_state *cstate, struct nfs4_stateowner *so, u32 seqid)
{
	if (nfsd4_has_session(cstate))
		return nfs_ok;
	if (seqid == so->so_seqid - 1)
		return nfserr_replay_me;
	if (seqid == so->so_seqid)
		return nfs_ok;
	return nfserr_bad_seqid;
}

static struct nfs4_client *lookup_clientid(clientid_t *clid, bool sessions,
						struct nfsd_net *nn)
{
	struct nfs4_client *found;

	spin_lock(&nn->client_lock);
	found = find_confirmed_client(clid, sessions, nn);
	if (found)
		atomic_inc(&found->cl_rpc_users);
	spin_unlock(&nn->client_lock);
	return found;
}

static __be32 set_client(clientid_t *clid,
		struct nfsd4_compound_state *cstate,
		struct nfsd_net *nn)
{
	if (cstate->clp) {
		if (!same_clid(&cstate->clp->cl_clientid, clid))
			return nfserr_stale_clientid;
		return nfs_ok;
	}
	if (STALE_CLIENTID(clid, nn))
		return nfserr_stale_clientid;
	/*
	 * We're in the 4.0 case (otherwise the SEQUENCE op would have
	 * set cstate->clp), so session = false:
	 */
	cstate->clp = lookup_clientid(clid, false, nn);
	if (!cstate->clp)
		return nfserr_expired;
	return nfs_ok;
}

__be32
nfsd4_process_open1(struct nfsd4_compound_state *cstate,
		    struct nfsd4_open *open, struct nfsd_net *nn)
{
	clientid_t *clientid = &open->op_clientid;
	struct nfs4_client *clp = NULL;
	unsigned int strhashval;
	struct nfs4_openowner *oo = NULL;
	__be32 status;

	/*
	 * In case we need it later, after we've already created the
	 * file and don't want to risk a further failure:
	 */
	open->op_file = nfsd4_alloc_file();
	if (open->op_file == NULL)
		return nfserr_jukebox;

	status = set_client(clientid, cstate, nn);
	if (status)
		return status;
	clp = cstate->clp;

	strhashval = ownerstr_hashval(&open->op_owner);
	oo = find_openstateowner_str(strhashval, open, clp);
	open->op_openowner = oo;
	if (!oo) {
		goto new_owner;
	}
	if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
		/* Replace unconfirmed owners without checking for replay. */
		release_openowner(oo);
		open->op_openowner = NULL;
		goto new_owner;
	}
	status = nfsd4_check_seqid(cstate, &oo->oo_owner, open->op_seqid);
	if (status)
		return status;
	goto alloc_stateid;
new_owner:
	oo = alloc_init_open_stateowner(strhashval, open, cstate);
	if (oo == NULL)
		return nfserr_jukebox;
	open->op_openowner = oo;
alloc_stateid:
	open->op_stp = nfs4_alloc_open_stateid(clp);
	if (!open->op_stp)
		return nfserr_jukebox;

	if (nfsd4_has_session(cstate) &&
	    (cstate->current_fh.fh_export->ex_flags & NFSEXP_PNFS)) {
		open->op_odstate = alloc_clnt_odstate(clp);
		if (!open->op_odstate)
			return nfserr_jukebox;
	}

	return nfs_ok;
}

static inline __be32
nfs4_check_delegmode(struct nfs4_delegation *dp, int flags)
{
	if ((flags & WR_STATE) && (dp->dl_type == NFS4_OPEN_DELEGATE_READ))
		return nfserr_openmode;
	else
		return nfs_ok;
}

static int share_access_to_flags(u32 share_access)
{
	return share_access == NFS4_SHARE_ACCESS_READ ? RD_STATE : WR_STATE;
}

static struct nfs4_delegation *find_deleg_stateid(struct nfs4_client *cl, stateid_t *s)
{
	struct nfs4_stid *ret;

	ret = find_stateid_by_type(cl, s,
				NFS4_DELEG_STID|NFS4_REVOKED_DELEG_STID);
	if (!ret)
		return NULL;
	return delegstateid(ret);
}

static bool nfsd4_is_deleg_cur(struct nfsd4_open *open)
{
	return open->op_claim_type == NFS4_OPEN_CLAIM_DELEGATE_CUR ||
	       open->op_claim_type == NFS4_OPEN_CLAIM_DELEG_CUR_FH;
}

static __be32
nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open,
		struct nfs4_delegation **dp)
{
	int flags;
	__be32 status = nfserr_bad_stateid;
	struct nfs4_delegation *deleg;

	deleg = find_deleg_stateid(cl, &open->op_delegate_stateid);
	if (deleg == NULL)
		goto out;
	if (deleg->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) {
		nfs4_put_stid(&deleg->dl_stid);
		if (cl->cl_minorversion)
			status = nfserr_deleg_revoked;
		goto out;
	}
	flags = share_access_to_flags(open->op_share_access);
	status = nfs4_check_delegmode(deleg, flags);
	if (status) {
		nfs4_put_stid(&deleg->dl_stid);
		goto out;
	}
	*dp = deleg;
out:
	if (!nfsd4_is_deleg_cur(open))
		return nfs_ok;
	if (status)
		return status;
	open->op_openowner->oo_flags |= NFS4_OO_CONFIRMED;
	return nfs_ok;
}

static inline int nfs4_access_to_access(u32 nfs4_access)
{
	int flags = 0;

	if (nfs4_access & NFS4_SHARE_ACCESS_READ)
		flags |= NFSD_MAY_READ;
	if (nfs4_access & NFS4_SHARE_ACCESS_WRITE)
		flags |= NFSD_MAY_WRITE;
	return flags;
}

static inline __be32
nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
		struct nfsd4_open *open)
{
	struct iattr iattr = {
		.ia_valid = ATTR_SIZE,
		.ia_size = 0,
	};
	struct nfsd_attrs attrs = {
		.na_iattr	= &iattr,
	};
	if (!open->op_truncate)
		return 0;
	if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
		return nfserr_inval;
	return nfsd_setattr(rqstp, fh, &attrs, 0, (time64_t)0);
}

static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
		struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
		struct nfsd4_open *open, bool new_stp)
{
	struct nfsd_file *nf = NULL;
	__be32 status;
	int oflag = nfs4_access_to_omode(open->op_share_access);
	int access = nfs4_access_to_access(open->op_share_access);
	unsigned char old_access_bmap, old_deny_bmap;

	spin_lock(&fp->fi_lock);

	/*
	 * Are we trying to set a deny mode that would conflict with
	 * current access?
	 */
	status = nfs4_file_check_deny(fp, open->op_share_deny);
	if (status != nfs_ok) {
		if (status != nfserr_share_denied) {
			spin_unlock(&fp->fi_lock);
			goto out;
		}
		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
				stp, open->op_share_deny, false))
			status = nfserr_jukebox;
		spin_unlock(&fp->fi_lock);
		goto out;
	}

	/* set access to the file */
	status = nfs4_file_get_access(fp, open->op_share_access);
	if (status != nfs_ok) {
		if (status != nfserr_share_denied) {
			spin_unlock(&fp->fi_lock);
			goto out;
		}
		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
				stp, open->op_share_access, true))
			status = nfserr_jukebox;
		spin_unlock(&fp->fi_lock);
		goto out;
	}

	/* Set access bits in stateid */
	old_access_bmap = stp->st_access_bmap;
	set_access(open->op_share_access, stp);

	/* Set new deny mask */
	old_deny_bmap = stp->st_deny_bmap;
	set_deny(open->op_share_deny, stp);
	fp->fi_share_deny |= (open->op_share_deny & NFS4_SHARE_DENY_BOTH);

	if (!fp->fi_fds[oflag]) {
		spin_unlock(&fp->fi_lock);

		status = nfsd_file_acquire_opened(rqstp, cur_fh, access,
						  open->op_filp, &nf);
		if (status != nfs_ok)
			goto out_put_access;

		spin_lock(&fp->fi_lock);
		if (!fp->fi_fds[oflag]) {
			fp->fi_fds[oflag] = nf;
			nf = NULL;
		}
	}
	spin_unlock(&fp->fi_lock);
	if (nf)
		nfsd_file_put(nf);

	status = nfserrno(nfsd_open_break_lease(cur_fh->fh_dentry->d_inode,
								access));
	if (status)
		goto out_put_access;

	status = nfsd4_truncate(rqstp, cur_fh, open);
	if (status)
		goto out_put_access;
out:
	return status;
out_put_access:
	stp->st_access_bmap = old_access_bmap;
	nfs4_file_put_access(fp, open->op_share_access);
	reset_union_bmap_deny(bmap_to_share_mode(old_deny_bmap), stp);
	goto out;
}

static __be32
nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
		struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
		struct nfsd4_open *open)
{
	__be32 status;
	unsigned char old_deny_bmap = stp->st_deny_bmap;

	if (!test_access(open->op_share_access, stp))
		return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open, false);

	/* test and set deny mode */
	spin_lock(&fp->fi_lock);
	status = nfs4_file_check_deny(fp, open->op_share_deny);
	switch (status) {
	case nfs_ok:
		set_deny(open->op_share_deny, stp);
		fp->fi_share_deny |=
			(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
		break;
	case nfserr_share_denied:
		if (nfs4_resolve_deny_conflicts_locked(fp, false,
				stp, open->op_share_deny, false))
			status = nfserr_jukebox;
		break;
	}
	spin_unlock(&fp->fi_lock);

	if (status != nfs_ok)
		return status;

	status = nfsd4_truncate(rqstp, cur_fh, open);
	if (status != nfs_ok)
		reset_union_bmap_deny(old_deny_bmap, stp);
	return status;
}

/* Should we give out recallable state?: */
static bool nfsd4_cb_channel_good(struct nfs4_client *clp)
{
	if (clp->cl_cb_state == NFSD4_CB_UP)
		return true;
	/*
	 * In the sessions case, since we don't have to establish a
	 * separate connection for callbacks, we assume it's OK
	 * until we hear otherwise:
	 */
	return clp->cl_minorversion && clp->cl_cb_state == NFSD4_CB_UNKNOWN;
}

static struct file_lock *nfs4_alloc_init_lease(struct nfs4_delegation *dp,
						int flag)
{
	struct file_lock *fl;

	fl = locks_alloc_lock();
	if (!fl)
		return NULL;
	fl->fl_lmops = &nfsd_lease_mng_ops;
	fl->fl_flags = FL_DELEG;
	fl->fl_type = flag == NFS4_OPEN_DELEGATE_READ? F_RDLCK: F_WRLCK;
	fl->fl_end = OFFSET_MAX;
	fl->fl_owner = (fl_owner_t)dp;
	fl->fl_pid = current->tgid;
	fl->fl_file = dp->dl_stid.sc_file->fi_deleg_file->nf_file;
	return fl;
}

static int nfsd4_check_conflicting_opens(struct nfs4_client *clp,
					 struct nfs4_file *fp)
{
	struct nfs4_ol_stateid *st;
	struct file *f = fp->fi_deleg_file->nf_file;
	struct inode *ino = locks_inode(f);
	int writes;

	writes = atomic_read(&ino->i_writecount);
	if (!writes)
		return 0;
	/*
	 * There could be multiple filehandles (hence multiple
	 * nfs4_files) referencing this file, but that's not too
	 * common; let's just give up in that case rather than
	 * trying to go look up all the clients using that other
	 * nfs4_file as well:
	 */
	if (fp->fi_aliased)
		return -EAGAIN;
	/*
	 * If there's a close in progress, make sure that we see it
	 * clear any fi_fds[] entries before we see it decrement
	 * i_writecount:
	 */
	smp_mb__after_atomic();

	if (fp->fi_fds[O_WRONLY])
		writes--;
	if (fp->fi_fds[O_RDWR])
		writes--;
	if (writes > 0)
		return -EAGAIN; /* There may be non-NFSv4 writers */
	/*
	 * It's possible there are non-NFSv4 write opens in progress,
	 * but if they haven't incremented i_writecount yet then they
	 * also haven't called break lease yet; so, they'll break this
	 * lease soon enough.  So, all that's left to check for is NFSv4
	 * opens:
	 */
	spin_lock(&fp->fi_lock);
	list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
		if (st->st_openstp == NULL /* it's an open */ &&
		    access_permit_write(st) &&
		    st->st_stid.sc_client != clp) {
			spin_unlock(&fp->fi_lock);
			return -EAGAIN;
		}
	}
	spin_unlock(&fp->fi_lock);
	/*
	 * There's a small chance that we could be racing with another
	 * NFSv4 open.  However, any open that hasn't added itself to
	 * the fi_stateids list also hasn't called break_lease yet; so,
	 * they'll break this lease soon enough.
	 */
	return 0;
}

/*
 * It's possible that between opening the dentry and setting the delegation,
 * that it has been renamed or unlinked. Redo the lookup to verify that this
 * hasn't happened.
 */
static int
nfsd4_verify_deleg_dentry(struct nfsd4_open *open, struct nfs4_file *fp,
			  struct svc_fh *parent)
{
	struct svc_export *exp;
	struct dentry *child;
	__be32 err;

	err = nfsd_lookup_dentry(open->op_rqstp, parent,
				 open->op_fname, open->op_fnamelen,
				 &exp, &child);

	if (err)
		return -EAGAIN;

	exp_put(exp);
	dput(child);
	if (child != file_dentry(fp->fi_deleg_file->nf_file))
		return -EAGAIN;

	return 0;
}

/*
 * We avoid breaking delegations held by a client due to its own activity, but
 * clearing setuid/setgid bits on a write is an implicit activity and the client
 * may not notice and continue using the old mode. Avoid giving out a delegation
 * on setuid/setgid files when the client is requesting an open for write.
 */
static int
nfsd4_verify_setuid_write(struct nfsd4_open *open, struct nfsd_file *nf)
{
	struct inode *inode = file_inode(nf->nf_file);

	if ((open->op_share_access & NFS4_SHARE_ACCESS_WRITE) &&
	    (inode->i_mode & (S_ISUID|S_ISGID)))
		return -EAGAIN;
	return 0;
}

static struct nfs4_delegation *
nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
		    struct svc_fh *parent)
{
	int status = 0;
	struct nfs4_client *clp = stp->st_stid.sc_client;
	struct nfs4_file *fp = stp->st_stid.sc_file;
	struct nfs4_clnt_odstate *odstate = stp->st_clnt_odstate;
	struct nfs4_delegation *dp;
	struct nfsd_file *nf;
	struct file_lock *fl;

	/*
	 * The fi_had_conflict and nfs_get_existing_delegation checks
	 * here are just optimizations; we'll need to recheck them at
	 * the end:
	 */
	if (fp->fi_had_conflict)
		return ERR_PTR(-EAGAIN);

	nf = find_readable_file(fp);
	if (!nf) {
		/*
		 * We probably could attempt another open and get a read
		 * delegation, but for now, don't bother until the
		 * client actually sends us one.
		 */
		return ERR_PTR(-EAGAIN);
	}
	spin_lock(&state_lock);
	spin_lock(&fp->fi_lock);
	if (nfs4_delegation_exists(clp, fp))
		status = -EAGAIN;
	else if (nfsd4_verify_setuid_write(open, nf))
		status = -EAGAIN;
	else if (!fp->fi_deleg_file) {
		fp->fi_deleg_file = nf;
		/* increment early to prevent fi_deleg_file from being
		 * cleared */
		fp->fi_delegees = 1;
		nf = NULL;
	} else
		fp->fi_delegees++;
	spin_unlock(&fp->fi_lock);
	spin_unlock(&state_lock);
	if (nf)
		nfsd_file_put(nf);
	if (status)
		return ERR_PTR(status);

	status = -ENOMEM;
	dp = alloc_init_deleg(clp, fp, odstate);
	if (!dp)
		goto out_delegees;

	fl = nfs4_alloc_init_lease(dp, NFS4_OPEN_DELEGATE_READ);
	if (!fl)
		goto out_clnt_odstate;

	status = vfs_setlease(fp->fi_deleg_file->nf_file, fl->fl_type, &fl, NULL);
	if (fl)
		locks_free_lock(fl);
	if (status)
		goto out_clnt_odstate;

	if (parent) {
		status = nfsd4_verify_deleg_dentry(open, fp, parent);
		if (status)
			goto out_unlock;
	}

	status = nfsd4_check_conflicting_opens(clp, fp);
	if (status)
		goto out_unlock;

	/*
	 * Now that the deleg is set, check again to ensure that nothing
	 * raced in and changed the mode while we weren't lookng.
	 */
	status = nfsd4_verify_setuid_write(open, fp->fi_deleg_file);
	if (status)
		goto out_unlock;

	spin_lock(&state_lock);
	spin_lock(&fp->fi_lock);
	if (fp->fi_had_conflict)
		status = -EAGAIN;
	else
		status = hash_delegation_locked(dp, fp);
	spin_unlock(&fp->fi_lock);
	spin_unlock(&state_lock);

	if (status)
		goto out_unlock;

	return dp;
out_unlock:
	vfs_setlease(fp->fi_deleg_file->nf_file, F_UNLCK, NULL, (void **)&dp);
out_clnt_odstate:
	put_clnt_odstate(dp->dl_clnt_odstate);
	nfs4_put_stid(&dp->dl_stid);
out_delegees:
	put_deleg_file(fp);
	return ERR_PTR(status);
}

static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
{
	open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
	if (status == -EAGAIN)
		open->op_why_no_deleg = WND4_CONTENTION;
	else {
		open->op_why_no_deleg = WND4_RESOURCE;
		switch (open->op_deleg_want) {
		case NFS4_SHARE_WANT_READ_DELEG:
		case NFS4_SHARE_WANT_WRITE_DELEG:
		case NFS4_SHARE_WANT_ANY_DELEG:
			break;
		case NFS4_SHARE_WANT_CANCEL:
			open->op_why_no_deleg = WND4_CANCELLED;
			break;
		case NFS4_SHARE_WANT_NO_DELEG:
			WARN_ON_ONCE(1);
		}
	}
}

/*
 * Attempt to hand out a delegation.
 *
 * Note we don't support write delegations, and won't until the vfs has
 * proper support for them.
 */
static void
nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
		     struct svc_fh *currentfh)
{
	struct nfs4_delegation *dp;
	struct nfs4_openowner *oo = openowner(stp->st_stateowner);
	struct nfs4_client *clp = stp->st_stid.sc_client;
	struct svc_fh *parent = NULL;
	int cb_up;
	int status = 0;

	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
	open->op_recall = 0;
	switch (open->op_claim_type) {
		case NFS4_OPEN_CLAIM_PREVIOUS:
			if (!cb_up)
				open->op_recall = 1;
			if (open->op_delegate_type != NFS4_OPEN_DELEGATE_READ)
				goto out_no_deleg;
			break;
		case NFS4_OPEN_CLAIM_NULL:
			parent = currentfh;
			fallthrough;
		case NFS4_OPEN_CLAIM_FH:
			/*
			 * Let's not give out any delegations till everyone's
			 * had the chance to reclaim theirs, *and* until
			 * NLM locks have all been reclaimed:
			 */
			if (locks_in_grace(clp->net))
				goto out_no_deleg;
			if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
				goto out_no_deleg;
			break;
		default:
			goto out_no_deleg;
	}
	dp = nfs4_set_delegation(open, stp, parent);
	if (IS_ERR(dp))
		goto out_no_deleg;

	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));

	trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
	open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
	nfs4_put_stid(&dp->dl_stid);
	return;
out_no_deleg:
	open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE;
	if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
	    open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE) {
		dprintk("NFSD: WARNING: refusing delegation reclaim\n");
		open->op_recall = 1;
	}

	/* 4.1 client asking for a delegation? */
	if (open->op_deleg_want)
		nfsd4_open_deleg_none_ext(open, status);
	return;
}

static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
					struct nfs4_delegation *dp)
{
	if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
	    dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
		open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
	} else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
		   dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
		open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
	}
	/* Otherwise the client must be confused wanting a delegation
	 * it already has, therefore we don't return
	 * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
	 */
}

/**
 * nfsd4_process_open2 - finish open processing
 * @rqstp: the RPC transaction being executed
 * @current_fh: NFSv4 COMPOUND's current filehandle
 * @open: OPEN arguments
 *
 * If successful, (1) truncate the file if open->op_truncate was
 * set, (2) set open->op_stateid, (3) set open->op_delegation.
 *
 * Returns %nfs_ok on success; otherwise an nfs4stat value in
 * network byte order is returned.
 */
__be32
nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
	struct nfsd4_compoundres *resp = rqstp->rq_resp;
	struct nfs4_client *cl = open->op_openowner->oo_owner.so_client;
	struct nfs4_file *fp = NULL;
	struct nfs4_ol_stateid *stp = NULL;
	struct nfs4_delegation *dp = NULL;
	__be32 status;
	bool new_stp = false;

	/*
	 * Lookup file; if found, lookup stateid and check open request,
	 * and check for delegations in the process of being recalled.
	 * If not found, create the nfs4_file struct
	 */
	fp = find_or_add_file(open->op_file, current_fh);
	if (fp != open->op_file) {
		status = nfs4_check_deleg(cl, open, &dp);
		if (status)
			goto out;
		stp = nfsd4_find_and_lock_existing_open(fp, open);
	} else {
		open->op_file = NULL;
		status = nfserr_bad_stateid;
		if (nfsd4_is_deleg_cur(open))
			goto out;
	}

	if (!stp) {
		stp = init_open_stateid(fp, open);
		if (!open->op_stp)
			new_stp = true;
	}

	/*
	 * OPEN the file, or upgrade an existing OPEN.
	 * If truncate fails, the OPEN fails.
	 *
	 * stp is already locked.
	 */
	if (!new_stp) {
		/* Stateid was found, this is an OPEN upgrade */
		status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open);
		if (status) {
			mutex_unlock(&stp->st_mutex);
			goto out;
		}
	} else {
		status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open, true);
		if (status) {
			stp->st_stid.sc_type = NFS4_CLOSED_STID;
			release_open_stateid(stp);
			mutex_unlock(&stp->st_mutex);
			goto out;
		}

		stp->st_clnt_odstate = find_or_hash_clnt_odstate(fp,
							open->op_odstate);
		if (stp->st_clnt_odstate == open->op_odstate)
			open->op_odstate = NULL;
	}

	nfs4_inc_and_copy_stateid(&open->op_stateid, &stp->st_stid);
	mutex_unlock(&stp->st_mutex);

	if (nfsd4_has_session(&resp->cstate)) {
		if (open->op_deleg_want & NFS4_SHARE_WANT_NO_DELEG) {
			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
			open->op_why_no_deleg = WND4_NOT_WANTED;
			goto nodeleg;
		}
	}

	/*
	* Attempt to hand out a delegation. No error return, because the
	* OPEN succeeds even if we fail.
	*/
	nfs4_open_delegation(open, stp, &resp->cstate.current_fh);
nodeleg:
	status = nfs_ok;
	trace_nfsd_open(&stp->st_stid.sc_stateid);
out:
	/* 4.1 client trying to upgrade/downgrade delegation? */
	if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&
	    open->op_deleg_want)
		nfsd4_deleg_xgrade_none_ext(open, dp);

	if (fp)
		put_nfs4_file(fp);
	if (status == 0 && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
		open->op_openowner->oo_flags |= NFS4_OO_CONFIRMED;
	/*
	* To finish the open response, we just need to set the rflags.
	*/
	open->op_rflags = NFS4_OPEN_RESULT_LOCKTYPE_POSIX;
	if (nfsd4_has_session(&resp->cstate))
		open->op_rflags |= NFS4_OPEN_RESULT_MAY_NOTIFY_LOCK;
	else if (!(open->op_openowner->oo_flags & NFS4_OO_CONFIRMED))
		open->op_rflags |= NFS4_OPEN_RESULT_CONFIRM;

	if (dp)
		nfs4_put_stid(&dp->dl_stid);
	if (stp)
		nfs4_put_stid(&stp->st_stid);

	return status;
}

void nfsd4_cleanup_open_state(struct nfsd4_compound_state *cstate,
			      struct nfsd4_open *open)
{
	if (open->op_openowner) {
		struct nfs4_stateowner *so = &open->op_openowner->oo_owner;

		nfsd4_cstate_assign_replay(cstate, so);
		nfs4_put_stateowner(so);
	}
	if (open->op_file)
		kmem_cache_free(file_slab, open->op_file);
	if (open->op_stp)
		nfs4_put_stid(&open->op_stp->st_stid);
	if (open->op_odstate)
		kmem_cache_free(odstate_slab, open->op_odstate);
}

__be32
nfsd4_renew(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
	    union nfsd4_op_u *u)
{
	clientid_t *clid = &u->renew;
	struct nfs4_client *clp;
	__be32 status;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	trace_nfsd_clid_renew(clid);
	status = set_client(clid, cstate, nn);
	if (status)
		return status;
	clp = cstate->clp;
	if (!list_empty(&clp->cl_delegations)
			&& clp->cl_cb_state != NFSD4_CB_UP)
		return nfserr_cb_path_down;
	return nfs_ok;
}

void
nfsd4_end_grace(struct nfsd_net *nn)
{
	/* do nothing if grace period already ended */
	if (nn->grace_ended)
		return;

	trace_nfsd_grace_complete(nn);
	nn->grace_ended = true;
	/*
	 * If the server goes down again right now, an NFSv4
	 * client will still be allowed to reclaim after it comes back up,
	 * even if it hasn't yet had a chance to reclaim state this time.
	 *
	 */
	nfsd4_record_grace_done(nn);
	/*
	 * At this point, NFSv4 clients can still reclaim.  But if the
	 * server crashes, any that have not yet reclaimed will be out
	 * of luck on the next boot.
	 *
	 * (NFSv4.1+ clients are considered to have reclaimed once they
	 * call RECLAIM_COMPLETE.  NFSv4.0 clients are considered to
	 * have reclaimed after their first OPEN.)
	 */
	locks_end_grace(&nn->nfsd4_manager);
	/*
	 * At this point, and once lockd and/or any other containers
	 * exit their grace period, further reclaims will fail and
	 * regular locking can resume.
	 */
}

/*
 * If we've waited a lease period but there are still clients trying to
 * reclaim, wait a little longer to give them a chance to finish.
 */
static bool clients_still_reclaiming(struct nfsd_net *nn)
{
	time64_t double_grace_period_end = nn->boot_time +
					   2 * nn->nfsd4_lease;

	if (nn->track_reclaim_completes &&
			atomic_read(&nn->nr_reclaim_complete) ==
			nn->reclaim_str_hashtbl_size)
		return false;
	if (!nn->somebody_reclaimed)
		return false;
	nn->somebody_reclaimed = false;
	/*
	 * If we've given them *two* lease times to reclaim, and they're
	 * still not done, give up:
	 */
	if (ktime_get_boottime_seconds() > double_grace_period_end)
		return false;
	return true;
}

struct laundry_time {
	time64_t cutoff;
	time64_t new_timeo;
};

static bool state_expired(struct laundry_time *lt, time64_t last_refresh)
{
	time64_t time_remaining;

	if (last_refresh < lt->cutoff)
		return true;
	time_remaining = last_refresh - lt->cutoff;
	lt->new_timeo = min(lt->new_timeo, time_remaining);
	return false;
}

#ifdef CONFIG_NFSD_V4_2_INTER_SSC
void nfsd4_ssc_init_umount_work(struct nfsd_net *nn)
{
	spin_lock_init(&nn->nfsd_ssc_lock);
	INIT_LIST_HEAD(&nn->nfsd_ssc_mount_list);
	init_waitqueue_head(&nn->nfsd_ssc_waitq);
}
EXPORT_SYMBOL_GPL(nfsd4_ssc_init_umount_work);

/*
 * This is called when nfsd is being shutdown, after all inter_ssc
 * cleanup were done, to destroy the ssc delayed unmount list.
 */
static void nfsd4_ssc_shutdown_umount(struct nfsd_net *nn)
{
	struct nfsd4_ssc_umount_item *ni = NULL;
	struct nfsd4_ssc_umount_item *tmp;

	spin_lock(&nn->nfsd_ssc_lock);
	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
		list_del(&ni->nsui_list);
		spin_unlock(&nn->nfsd_ssc_lock);
		mntput(ni->nsui_vfsmount);
		kfree(ni);
		spin_lock(&nn->nfsd_ssc_lock);
	}
	spin_unlock(&nn->nfsd_ssc_lock);
}

static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
{
	bool do_wakeup = false;
	struct nfsd4_ssc_umount_item *ni = NULL;
	struct nfsd4_ssc_umount_item *tmp;

	spin_lock(&nn->nfsd_ssc_lock);
	list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
		if (time_after(jiffies, ni->nsui_expire)) {
			if (refcount_read(&ni->nsui_refcnt) > 1)
				continue;

			/* mark being unmount */
			ni->nsui_busy = true;
			spin_unlock(&nn->nfsd_ssc_lock);
			mntput(ni->nsui_vfsmount);
			spin_lock(&nn->nfsd_ssc_lock);

			/* waiters need to start from begin of list */
			list_del(&ni->nsui_list);
			kfree(ni);

			/* wakeup ssc_connect waiters */
			do_wakeup = true;
			continue;
		}
		break;
	}
	if (do_wakeup)
		wake_up_all(&nn->nfsd_ssc_waitq);
	spin_unlock(&nn->nfsd_ssc_lock);
}
#endif

/* Check if any lock belonging to this lockowner has any blockers */
static bool
nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo)
{
	struct file_lock_context *ctx;
	struct nfs4_ol_stateid *stp;
	struct nfs4_file *nf;

	list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) {
		nf = stp->st_stid.sc_file;
		ctx = nf->fi_inode->i_flctx;
		if (!ctx)
			continue;
		if (locks_owner_has_blockers(ctx, lo))
			return true;
	}
	return false;
}

static bool
nfs4_anylock_blockers(struct nfs4_client *clp)
{
	int i;
	struct nfs4_stateowner *so;
	struct nfs4_lockowner *lo;

	if (atomic_read(&clp->cl_delegs_in_recall))
		return true;
	spin_lock(&clp->cl_lock);
	for (i = 0; i < OWNER_HASH_SIZE; i++) {
		list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[i],
				so_strhash) {
			if (so->so_is_open_owner)
				continue;
			lo = lockowner(so);
			if (nfs4_lockowner_has_blockers(lo)) {
				spin_unlock(&clp->cl_lock);
				return true;
			}
		}
	}
	spin_unlock(&clp->cl_lock);
	return false;
}

static void
nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
				struct laundry_time *lt)
{
	unsigned int maxreap, reapcnt = 0;
	struct list_head *pos, *next;
	struct nfs4_client *clp;

	maxreap = (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) ?
			NFSD_CLIENT_MAX_TRIM_PER_RUN : 0;
	INIT_LIST_HEAD(reaplist);
	spin_lock(&nn->client_lock);
	list_for_each_safe(pos, next, &nn->client_lru) {
		clp = list_entry(pos, struct nfs4_client, cl_lru);
		if (clp->cl_state == NFSD4_EXPIRABLE)
			goto exp_client;
		if (!state_expired(lt, clp->cl_time))
			break;
		if (!atomic_read(&clp->cl_rpc_users)) {
			if (clp->cl_state == NFSD4_ACTIVE)
				atomic_inc(&nn->nfsd_courtesy_clients);
			clp->cl_state = NFSD4_COURTESY;
		}
		if (!client_has_state(clp))
			goto exp_client;
		if (!nfs4_anylock_blockers(clp))
			if (reapcnt >= maxreap)
				continue;
exp_client:
		if (!mark_client_expired_locked(clp)) {
			list_add(&clp->cl_lru, reaplist);
			reapcnt++;
		}
	}
	spin_unlock(&nn->client_lock);
}

static void
nfs4_get_courtesy_client_reaplist(struct nfsd_net *nn,
				struct list_head *reaplist)
{
	unsigned int maxreap = 0, reapcnt = 0;
	struct list_head *pos, *next;
	struct nfs4_client *clp;

	maxreap = NFSD_CLIENT_MAX_TRIM_PER_RUN;
	INIT_LIST_HEAD(reaplist);

	spin_lock(&nn->client_lock);
	list_for_each_safe(pos, next, &nn->client_lru) {
		clp = list_entry(pos, struct nfs4_client, cl_lru);
		if (clp->cl_state == NFSD4_ACTIVE)
			break;
		if (reapcnt >= maxreap)
			break;
		if (!mark_client_expired_locked(clp)) {
			list_add(&clp->cl_lru, reaplist);
			reapcnt++;
		}
	}
	spin_unlock(&nn->client_lock);
}

static void
nfs4_process_client_reaplist(struct list_head *reaplist)
{
	struct list_head *pos, *next;
	struct nfs4_client *clp;

	list_for_each_safe(pos, next, reaplist) {
		clp = list_entry(pos, struct nfs4_client, cl_lru);
		trace_nfsd_clid_purged(&clp->cl_clientid);
		list_del_init(&clp->cl_lru);
		expire_client(clp);
	}
}

static time64_t
nfs4_laundromat(struct nfsd_net *nn)
{
	struct nfs4_openowner *oo;
	struct nfs4_delegation *dp;
	struct nfs4_ol_stateid *stp;
	struct nfsd4_blocked_lock *nbl;
	struct list_head *pos, *next, reaplist;
	struct laundry_time lt = {
		.cutoff = ktime_get_boottime_seconds() - nn->nfsd4_lease,
		.new_timeo = nn->nfsd4_lease
	};
	struct nfs4_cpntf_state *cps;
	copy_stateid_t *cps_t;
	int i;

	if (clients_still_reclaiming(nn)) {
		lt.new_timeo = 0;
		goto out;
	}
	nfsd4_end_grace(nn);

	spin_lock(&nn->s2s_cp_lock);
	idr_for_each_entry(&nn->s2s_cp_stateids, cps_t, i) {
		cps = container_of(cps_t, struct nfs4_cpntf_state, cp_stateid);
		if (cps->cp_stateid.cs_type == NFS4_COPYNOTIFY_STID &&
				state_expired(&lt, cps->cpntf_time))
			_free_cpntf_state_locked(nn, cps);
	}
	spin_unlock(&nn->s2s_cp_lock);
	nfs4_get_client_reaplist(nn, &reaplist, &lt);
	nfs4_process_client_reaplist(&reaplist);

	spin_lock(&state_lock);
	list_for_each_safe(pos, next, &nn->del_recall_lru) {
		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
		if (!state_expired(&lt, dp->dl_time))
			break;
		WARN_ON(!unhash_delegation_locked(dp));
		list_add(&dp->dl_recall_lru, &reaplist);
	}
	spin_unlock(&state_lock);
	while (!list_empty(&reaplist)) {
		dp = list_first_entry(&reaplist, struct nfs4_delegation,
					dl_recall_lru);
		list_del_init(&dp->dl_recall_lru);
		revoke_delegation(dp);
	}

	spin_lock(&nn->client_lock);
	while (!list_empty(&nn->close_lru)) {
		oo = list_first_entry(&nn->close_lru, struct nfs4_openowner,
					oo_close_lru);
		if (!state_expired(&lt, oo->oo_time))
			break;
		list_del_init(&oo->oo_close_lru);
		stp = oo->oo_last_closed_stid;
		oo->oo_last_closed_stid = NULL;
		spin_unlock(&nn->client_lock);
		nfs4_put_stid(&stp->st_stid);
		spin_lock(&nn->client_lock);
	}
	spin_unlock(&nn->client_lock);

	/*
	 * It's possible for a client to try and acquire an already held lock
	 * that is being held for a long time, and then lose interest in it.
	 * So, we clean out any un-revisited request after a lease period
	 * under the assumption that the client is no longer interested.
	 *
	 * RFC5661, sec. 9.6 states that the client must not rely on getting
	 * notifications and must continue to poll for locks, even when the
	 * server supports them. Thus this shouldn't lead to clients blocking
	 * indefinitely once the lock does become free.
	 */
	BUG_ON(!list_empty(&reaplist));
	spin_lock(&nn->blocked_locks_lock);
	while (!list_empty(&nn->blocked_locks_lru)) {
		nbl = list_first_entry(&nn->blocked_locks_lru,
					struct nfsd4_blocked_lock, nbl_lru);
		if (!state_expired(&lt, nbl->nbl_time))
			break;
		list_move(&nbl->nbl_lru, &reaplist);
		list_del_init(&nbl->nbl_list);
	}
	spin_unlock(&nn->blocked_locks_lock);

	while (!list_empty(&reaplist)) {
		nbl = list_first_entry(&reaplist,
					struct nfsd4_blocked_lock, nbl_lru);
		list_del_init(&nbl->nbl_lru);
		free_blocked_lock(nbl);
	}
#ifdef CONFIG_NFSD_V4_2_INTER_SSC
	/* service the server-to-server copy delayed unmount list */
	nfsd4_ssc_expire_umount(nn);
#endif
out:
	return max_t(time64_t, lt.new_timeo, NFSD_LAUNDROMAT_MINTIMEOUT);
}

static void laundromat_main(struct work_struct *);

static void
laundromat_main(struct work_struct *laundry)
{
	time64_t t;
	struct delayed_work *dwork = to_delayed_work(laundry);
	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
					   laundromat_work);

	t = nfs4_laundromat(nn);
	queue_delayed_work(laundry_wq, &nn->laundromat_work, t*HZ);
}

static void
courtesy_client_reaper(struct work_struct *reaper)
{
	struct list_head reaplist;
	struct delayed_work *dwork = to_delayed_work(reaper);
	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
					nfsd_shrinker_work);

	nfs4_get_courtesy_client_reaplist(nn, &reaplist);
	nfs4_process_client_reaplist(&reaplist);
}

static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp)
{
	if (!fh_match(&fhp->fh_handle, &stp->sc_file->fi_fhandle))
		return nfserr_bad_stateid;
	return nfs_ok;
}

static
__be32 nfs4_check_openmode(struct nfs4_ol_stateid *stp, int flags)
{
        __be32 status = nfserr_openmode;

	/* For lock stateid's, we test the parent open, not the lock: */
	if (stp->st_openstp)
		stp = stp->st_openstp;
	if ((flags & WR_STATE) && !access_permit_write(stp))
                goto out;
	if ((flags & RD_STATE) && !access_permit_read(stp))
                goto out;
	status = nfs_ok;
out:
	return status;
}

static inline __be32
check_special_stateids(struct net *net, svc_fh *current_fh, stateid_t *stateid, int flags)
{
	if (ONE_STATEID(stateid) && (flags & RD_STATE))
		return nfs_ok;
	else if (opens_in_grace(net)) {
		/* Answer in remaining cases depends on existence of
		 * conflicting state; so we must wait out the grace period. */
		return nfserr_grace;
	} else if (flags & WR_STATE)
		return nfs4_share_conflict(current_fh,
				NFS4_SHARE_DENY_WRITE);
	else /* (flags & RD_STATE) && ZERO_STATEID(stateid) */
		return nfs4_share_conflict(current_fh,
				NFS4_SHARE_DENY_READ);
}

static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_session)
{
	/*
	 * When sessions are used the stateid generation number is ignored
	 * when it is zero.
	 */
	if (has_session && in->si_generation == 0)
		return nfs_ok;

	if (in->si_generation == ref->si_generation)
		return nfs_ok;

	/* If the client sends us a stateid from the future, it's buggy: */
	if (nfsd4_stateid_generation_after(in, ref))
		return nfserr_bad_stateid;
	/*
	 * However, we could see a stateid from the past, even from a
	 * non-buggy client.  For example, if the client sends a lock
	 * while some IO is outstanding, the lock may bump si_generation
	 * while the IO is still in flight.  The client could avoid that
	 * situation by waiting for responses on all the IO requests,
	 * but better performance may result in retrying IO that
	 * receives an old_stateid error if requests are rarely
	 * reordered in flight:
	 */
	return nfserr_old_stateid;
}

static __be32 nfsd4_stid_check_stateid_generation(stateid_t *in, struct nfs4_stid *s, bool has_session)
{
	__be32 ret;

	spin_lock(&s->sc_lock);
	ret = nfsd4_verify_open_stid(s);
	if (ret == nfs_ok)
		ret = check_stateid_generation(in, &s->sc_stateid, has_session);
	spin_unlock(&s->sc_lock);
	return ret;
}

static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols)
{
	if (ols->st_stateowner->so_is_open_owner &&
	    !(openowner(ols->st_stateowner)->oo_flags & NFS4_OO_CONFIRMED))
		return nfserr_bad_stateid;
	return nfs_ok;
}

static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
{
	struct nfs4_stid *s;
	__be32 status = nfserr_bad_stateid;

	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
		CLOSE_STATEID(stateid))
		return status;
	if (!same_clid(&stateid->si_opaque.so_clid, &cl->cl_clientid))
		return status;
	spin_lock(&cl->cl_lock);
	s = find_stateid_locked(cl, stateid);
	if (!s)
		goto out_unlock;
	status = nfsd4_stid_check_stateid_generation(stateid, s, 1);
	if (status)
		goto out_unlock;
	switch (s->sc_type) {
	case NFS4_DELEG_STID:
		status = nfs_ok;
		break;
	case NFS4_REVOKED_DELEG_STID:
		status = nfserr_deleg_revoked;
		break;
	case NFS4_OPEN_STID:
	case NFS4_LOCK_STID:
		status = nfsd4_check_openowner_confirmed(openlockstateid(s));
		break;
	default:
		printk("unknown stateid type %x\n", s->sc_type);
		fallthrough;
	case NFS4_CLOSED_STID:
	case NFS4_CLOSED_DELEG_STID:
		status = nfserr_bad_stateid;
	}
out_unlock:
	spin_unlock(&cl->cl_lock);
	return status;
}

__be32
nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
		     stateid_t *stateid, unsigned char typemask,
		     struct nfs4_stid **s, struct nfsd_net *nn)
{
	__be32 status;
	struct nfs4_stid *stid;
	bool return_revoked = false;

	/*
	 *  only return revoked delegations if explicitly asked.
	 *  otherwise we report revoked or bad_stateid status.
	 */
	if (typemask & NFS4_REVOKED_DELEG_STID)
		return_revoked = true;
	else if (typemask & NFS4_DELEG_STID)
		typemask |= NFS4_REVOKED_DELEG_STID;

	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
		CLOSE_STATEID(stateid))
		return nfserr_bad_stateid;
	status = set_client(&stateid->si_opaque.so_clid, cstate, nn);
	if (status == nfserr_stale_clientid) {
		if (cstate->session)
			return nfserr_bad_stateid;
		return nfserr_stale_stateid;
	}
	if (status)
		return status;
	stid = find_stateid_by_type(cstate->clp, stateid, typemask);
	if (!stid)
		return nfserr_bad_stateid;
	if ((stid->sc_type == NFS4_REVOKED_DELEG_STID) && !return_revoked) {
		nfs4_put_stid(stid);
		if (cstate->minorversion)
			return nfserr_deleg_revoked;
		return nfserr_bad_stateid;
	}
	*s = stid;
	return nfs_ok;
}

static struct nfsd_file *
nfs4_find_file(struct nfs4_stid *s, int flags)
{
	if (!s)
		return NULL;

	switch (s->sc_type) {
	case NFS4_DELEG_STID:
		if (WARN_ON_ONCE(!s->sc_file->fi_deleg_file))
			return NULL;
		return nfsd_file_get(s->sc_file->fi_deleg_file);
	case NFS4_OPEN_STID:
	case NFS4_LOCK_STID:
		if (flags & RD_STATE)
			return find_readable_file(s->sc_file);
		else
			return find_writeable_file(s->sc_file);
	}

	return NULL;
}

static __be32
nfs4_check_olstateid(struct nfs4_ol_stateid *ols, int flags)
{
	__be32 status;

	status = nfsd4_check_openowner_confirmed(ols);
	if (status)
		return status;
	return nfs4_check_openmode(ols, flags);
}

static __be32
nfs4_check_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfs4_stid *s,
		struct nfsd_file **nfp, int flags)
{
	int acc = (flags & RD_STATE) ? NFSD_MAY_READ : NFSD_MAY_WRITE;
	struct nfsd_file *nf;
	__be32 status;

	nf = nfs4_find_file(s, flags);
	if (nf) {
		status = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
				acc | NFSD_MAY_OWNER_OVERRIDE);
		if (status) {
			nfsd_file_put(nf);
			goto out;
		}
	} else {
		status = nfsd_file_acquire(rqstp, fhp, acc, &nf);
		if (status)
			return status;
	}
	*nfp = nf;
out:
	return status;
}
static void
_free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps)
{
	WARN_ON_ONCE(cps->cp_stateid.cs_type != NFS4_COPYNOTIFY_STID);
	if (!refcount_dec_and_test(&cps->cp_stateid.cs_count))
		return;
	list_del(&cps->cp_list);
	idr_remove(&nn->s2s_cp_stateids,
		   cps->cp_stateid.cs_stid.si_opaque.so_id);
	kfree(cps);
}
/*
 * A READ from an inter server to server COPY will have a
 * copy stateid. Look up the copy notify stateid from the
 * idr structure and take a reference on it.
 */
__be32 manage_cpntf_state(struct nfsd_net *nn, stateid_t *st,
			  struct nfs4_client *clp,
			  struct nfs4_cpntf_state **cps)
{
	copy_stateid_t *cps_t;
	struct nfs4_cpntf_state *state = NULL;

	if (st->si_opaque.so_clid.cl_id != nn->s2s_cp_cl_id)
		return nfserr_bad_stateid;
	spin_lock(&nn->s2s_cp_lock);
	cps_t = idr_find(&nn->s2s_cp_stateids, st->si_opaque.so_id);
	if (cps_t) {
		state = container_of(cps_t, struct nfs4_cpntf_state,
				     cp_stateid);
		if (state->cp_stateid.cs_type != NFS4_COPYNOTIFY_STID) {
			state = NULL;
			goto unlock;
		}
		if (!clp)
			refcount_inc(&state->cp_stateid.cs_count);
		else
			_free_cpntf_state_locked(nn, state);
	}
unlock:
	spin_unlock(&nn->s2s_cp_lock);
	if (!state)
		return nfserr_bad_stateid;
	if (!clp && state)
		*cps = state;
	return 0;
}

static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
			       struct nfs4_stid **stid)
{
	__be32 status;
	struct nfs4_cpntf_state *cps = NULL;
	struct nfs4_client *found;

	status = manage_cpntf_state(nn, st, NULL, &cps);
	if (status)
		return status;

	cps->cpntf_time = ktime_get_boottime_seconds();

	status = nfserr_expired;
	found = lookup_clientid(&cps->cp_p_clid, true, nn);
	if (!found)
		goto out;

	*stid = find_stateid_by_type(found, &cps->cp_p_stateid,
			NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID);
	if (*stid)
		status = nfs_ok;
	else
		status = nfserr_bad_stateid;

	put_client_renew(found);
out:
	nfs4_put_cpntf_state(nn, cps);
	return status;
}

void nfs4_put_cpntf_state(struct nfsd_net *nn, struct nfs4_cpntf_state *cps)
{
	spin_lock(&nn->s2s_cp_lock);
	_free_cpntf_state_locked(nn, cps);
	spin_unlock(&nn->s2s_cp_lock);
}

/*
 * Checks for stateid operations
 */
__be32
nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *cstate, struct svc_fh *fhp,
		stateid_t *stateid, int flags, struct nfsd_file **nfp,
		struct nfs4_stid **cstid)
{
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	struct nfs4_stid *s = NULL;
	__be32 status;

	if (nfp)
		*nfp = NULL;

	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid)) {
		if (cstid)
			status = nfserr_bad_stateid;
		else
			status = check_special_stateids(net, fhp, stateid,
									flags);
		goto done;
	}

	status = nfsd4_lookup_stateid(cstate, stateid,
				NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID,
				&s, nn);
	if (status == nfserr_bad_stateid)
		status = find_cpntf_state(nn, stateid, &s);
	if (status)
		return status;
	status = nfsd4_stid_check_stateid_generation(stateid, s,
			nfsd4_has_session(cstate));
	if (status)
		goto out;

	switch (s->sc_type) {
	case NFS4_DELEG_STID:
		status = nfs4_check_delegmode(delegstateid(s), flags);
		break;
	case NFS4_OPEN_STID:
	case NFS4_LOCK_STID:
		status = nfs4_check_olstateid(openlockstateid(s), flags);
		break;
	default:
		status = nfserr_bad_stateid;
		break;
	}
	if (status)
		goto out;
	status = nfs4_check_fh(fhp, s);

done:
	if (status == nfs_ok && nfp)
		status = nfs4_check_file(rqstp, fhp, s, nfp, flags);
out:
	if (s) {
		if (!status && cstid)
			*cstid = s;
		else
			nfs4_put_stid(s);
	}
	return status;
}

/*
 * Test if the stateid is valid
 */
__be32
nfsd4_test_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		   union nfsd4_op_u *u)
{
	struct nfsd4_test_stateid *test_stateid = &u->test_stateid;
	struct nfsd4_test_stateid_id *stateid;
	struct nfs4_client *cl = cstate->clp;

	list_for_each_entry(stateid, &test_stateid->ts_stateid_list, ts_id_list)
		stateid->ts_id_status =
			nfsd4_validate_stateid(cl, &stateid->ts_id_stateid);

	return nfs_ok;
}

static __be32
nfsd4_free_lock_stateid(stateid_t *stateid, struct nfs4_stid *s)
{
	struct nfs4_ol_stateid *stp = openlockstateid(s);
	__be32 ret;

	ret = nfsd4_lock_ol_stateid(stp);
	if (ret)
		goto out_put_stid;

	ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
	if (ret)
		goto out;

	ret = nfserr_locks_held;
	if (check_for_locks(stp->st_stid.sc_file,
			    lockowner(stp->st_stateowner)))
		goto out;

	release_lock_stateid(stp);
	ret = nfs_ok;

out:
	mutex_unlock(&stp->st_mutex);
out_put_stid:
	nfs4_put_stid(s);
	return ret;
}

__be32
nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		   union nfsd4_op_u *u)
{
	struct nfsd4_free_stateid *free_stateid = &u->free_stateid;
	stateid_t *stateid = &free_stateid->fr_stateid;
	struct nfs4_stid *s;
	struct nfs4_delegation *dp;
	struct nfs4_client *cl = cstate->clp;
	__be32 ret = nfserr_bad_stateid;

	spin_lock(&cl->cl_lock);
	s = find_stateid_locked(cl, stateid);
	if (!s)
		goto out_unlock;
	spin_lock(&s->sc_lock);
	switch (s->sc_type) {
	case NFS4_DELEG_STID:
		ret = nfserr_locks_held;
		break;
	case NFS4_OPEN_STID:
		ret = check_stateid_generation(stateid, &s->sc_stateid, 1);
		if (ret)
			break;
		ret = nfserr_locks_held;
		break;
	case NFS4_LOCK_STID:
		spin_unlock(&s->sc_lock);
		refcount_inc(&s->sc_count);
		spin_unlock(&cl->cl_lock);
		ret = nfsd4_free_lock_stateid(stateid, s);
		goto out;
	case NFS4_REVOKED_DELEG_STID:
		spin_unlock(&s->sc_lock);
		dp = delegstateid(s);
		list_del_init(&dp->dl_recall_lru);
		spin_unlock(&cl->cl_lock);
		nfs4_put_stid(s);
		ret = nfs_ok;
		goto out;
	/* Default falls through and returns nfserr_bad_stateid */
	}
	spin_unlock(&s->sc_lock);
out_unlock:
	spin_unlock(&cl->cl_lock);
out:
	return ret;
}

static inline int
setlkflg (int type)
{
	return (type == NFS4_READW_LT || type == NFS4_READ_LT) ?
		RD_STATE : WR_STATE;
}

static __be32 nfs4_seqid_op_checks(struct nfsd4_compound_state *cstate, stateid_t *stateid, u32 seqid, struct nfs4_ol_stateid *stp)
{
	struct svc_fh *current_fh = &cstate->current_fh;
	struct nfs4_stateowner *sop = stp->st_stateowner;
	__be32 status;

	status = nfsd4_check_seqid(cstate, sop, seqid);
	if (status)
		return status;
	status = nfsd4_lock_ol_stateid(stp);
	if (status != nfs_ok)
		return status;
	status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
	if (status == nfs_ok)
		status = nfs4_check_fh(current_fh, &stp->st_stid);
	if (status != nfs_ok)
		mutex_unlock(&stp->st_mutex);
	return status;
}

/* 
 * Checks for sequence id mutating operations. 
 */
static __be32
nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
			 stateid_t *stateid, char typemask,
			 struct nfs4_ol_stateid **stpp,
			 struct nfsd_net *nn)
{
	__be32 status;
	struct nfs4_stid *s;
	struct nfs4_ol_stateid *stp = NULL;

	trace_nfsd_preprocess(seqid, stateid);

	*stpp = NULL;
	status = nfsd4_lookup_stateid(cstate, stateid, typemask, &s, nn);
	if (status)
		return status;
	stp = openlockstateid(s);
	nfsd4_cstate_assign_replay(cstate, stp->st_stateowner);

	status = nfs4_seqid_op_checks(cstate, stateid, seqid, stp);
	if (!status)
		*stpp = stp;
	else
		nfs4_put_stid(&stp->st_stid);
	return status;
}

static __be32 nfs4_preprocess_confirmed_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
						 stateid_t *stateid, struct nfs4_ol_stateid **stpp, struct nfsd_net *nn)
{
	__be32 status;
	struct nfs4_openowner *oo;
	struct nfs4_ol_stateid *stp;

	status = nfs4_preprocess_seqid_op(cstate, seqid, stateid,
						NFS4_OPEN_STID, &stp, nn);
	if (status)
		return status;
	oo = openowner(stp->st_stateowner);
	if (!(oo->oo_flags & NFS4_OO_CONFIRMED)) {
		mutex_unlock(&stp->st_mutex);
		nfs4_put_stid(&stp->st_stid);
		return nfserr_bad_stateid;
	}
	*stpp = stp;
	return nfs_ok;
}

__be32
nfsd4_open_confirm(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		   union nfsd4_op_u *u)
{
	struct nfsd4_open_confirm *oc = &u->open_confirm;
	__be32 status;
	struct nfs4_openowner *oo;
	struct nfs4_ol_stateid *stp;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	dprintk("NFSD: nfsd4_open_confirm on file %pd\n",
			cstate->current_fh.fh_dentry);

	status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0);
	if (status)
		return status;

	status = nfs4_preprocess_seqid_op(cstate,
					oc->oc_seqid, &oc->oc_req_stateid,
					NFS4_OPEN_STID, &stp, nn);
	if (status)
		goto out;
	oo = openowner(stp->st_stateowner);
	status = nfserr_bad_stateid;
	if (oo->oo_flags & NFS4_OO_CONFIRMED) {
		mutex_unlock(&stp->st_mutex);
		goto put_stateid;
	}
	oo->oo_flags |= NFS4_OO_CONFIRMED;
	nfs4_inc_and_copy_stateid(&oc->oc_resp_stateid, &stp->st_stid);
	mutex_unlock(&stp->st_mutex);
	trace_nfsd_open_confirm(oc->oc_seqid, &stp->st_stid.sc_stateid);
	nfsd4_client_record_create(oo->oo_owner.so_client);
	status = nfs_ok;
put_stateid:
	nfs4_put_stid(&stp->st_stid);
out:
	nfsd4_bump_seqid(cstate, status);
	return status;
}

static inline void nfs4_stateid_downgrade_bit(struct nfs4_ol_stateid *stp, u32 access)
{
	if (!test_access(access, stp))
		return;
	nfs4_file_put_access(stp->st_stid.sc_file, access);
	clear_access(access, stp);
}

static inline void nfs4_stateid_downgrade(struct nfs4_ol_stateid *stp, u32 to_access)
{
	switch (to_access) {
	case NFS4_SHARE_ACCESS_READ:
		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_WRITE);
		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_BOTH);
		break;
	case NFS4_SHARE_ACCESS_WRITE:
		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_READ);
		nfs4_stateid_downgrade_bit(stp, NFS4_SHARE_ACCESS_BOTH);
		break;
	case NFS4_SHARE_ACCESS_BOTH:
		break;
	default:
		WARN_ON_ONCE(1);
	}
}

__be32
nfsd4_open_downgrade(struct svc_rqst *rqstp,
		     struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
{
	struct nfsd4_open_downgrade *od = &u->open_downgrade;
	__be32 status;
	struct nfs4_ol_stateid *stp;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	dprintk("NFSD: nfsd4_open_downgrade on file %pd\n", 
			cstate->current_fh.fh_dentry);

	/* We don't yet support WANT bits: */
	if (od->od_deleg_want)
		dprintk("NFSD: %s: od_deleg_want=0x%x ignored\n", __func__,
			od->od_deleg_want);

	status = nfs4_preprocess_confirmed_seqid_op(cstate, od->od_seqid,
					&od->od_stateid, &stp, nn);
	if (status)
		goto out; 
	status = nfserr_inval;
	if (!test_access(od->od_share_access, stp)) {
		dprintk("NFSD: access not a subset of current bitmap: 0x%hhx, input access=%08x\n",
			stp->st_access_bmap, od->od_share_access);
		goto put_stateid;
	}
	if (!test_deny(od->od_share_deny, stp)) {
		dprintk("NFSD: deny not a subset of current bitmap: 0x%hhx, input deny=%08x\n",
			stp->st_deny_bmap, od->od_share_deny);
		goto put_stateid;
	}
	nfs4_stateid_downgrade(stp, od->od_share_access);
	reset_union_bmap_deny(od->od_share_deny, stp);
	nfs4_inc_and_copy_stateid(&od->od_stateid, &stp->st_stid);
	status = nfs_ok;
put_stateid:
	mutex_unlock(&stp->st_mutex);
	nfs4_put_stid(&stp->st_stid);
out:
	nfsd4_bump_seqid(cstate, status);
	return status;
}

static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
{
	struct nfs4_client *clp = s->st_stid.sc_client;
	bool unhashed;
	LIST_HEAD(reaplist);
	struct nfs4_ol_stateid *stp;

	spin_lock(&clp->cl_lock);
	unhashed = unhash_open_stateid(s, &reaplist);

	if (clp->cl_minorversion) {
		if (unhashed)
			put_ol_stateid_locked(s, &reaplist);
		spin_unlock(&clp->cl_lock);
		list_for_each_entry(stp, &reaplist, st_locks)
			nfs4_free_cpntf_statelist(clp->net, &stp->st_stid);
		free_ol_stateid_reaplist(&reaplist);
	} else {
		spin_unlock(&clp->cl_lock);
		free_ol_stateid_reaplist(&reaplist);
		if (unhashed)
			move_to_close_lru(s, clp->net);
	}
}

/*
 * nfs4_unlock_state() called after encode
 */
__be32
nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	struct nfsd4_close *close = &u->close;
	__be32 status;
	struct nfs4_ol_stateid *stp;
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	dprintk("NFSD: nfsd4_close on file %pd\n", 
			cstate->current_fh.fh_dentry);

	status = nfs4_preprocess_seqid_op(cstate, close->cl_seqid,
					&close->cl_stateid,
					NFS4_OPEN_STID|NFS4_CLOSED_STID,
					&stp, nn);
	nfsd4_bump_seqid(cstate, status);
	if (status)
		goto out; 

	stp->st_stid.sc_type = NFS4_CLOSED_STID;

	/*
	 * Technically we don't _really_ have to increment or copy it, since
	 * it should just be gone after this operation and we clobber the
	 * copied value below, but we continue to do so here just to ensure
	 * that racing ops see that there was a state change.
	 */
	nfs4_inc_and_copy_stateid(&close->cl_stateid, &stp->st_stid);

	nfsd4_close_open_stateid(stp);
	mutex_unlock(&stp->st_mutex);

	/* v4.1+ suggests that we send a special stateid in here, since the
	 * clients should just ignore this anyway. Since this is not useful
	 * for v4.0 clients either, we set it to the special close_stateid
	 * universally.
	 *
	 * See RFC5661 section 18.2.4, and RFC7530 section 16.2.5
	 */
	memcpy(&close->cl_stateid, &close_stateid, sizeof(close->cl_stateid));

	/* put reference from nfs4_preprocess_seqid_op */
	nfs4_put_stid(&stp->st_stid);
out:
	return status;
}

__be32
nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
		  union nfsd4_op_u *u)
{
	struct nfsd4_delegreturn *dr = &u->delegreturn;
	struct nfs4_delegation *dp;
	stateid_t *stateid = &dr->dr_stateid;
	struct nfs4_stid *s;
	__be32 status;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
		return status;

	status = nfsd4_lookup_stateid(cstate, stateid, NFS4_DELEG_STID, &s, nn);
	if (status)
		goto out;
	dp = delegstateid(s);
	status = nfsd4_stid_check_stateid_generation(stateid, &dp->dl_stid, nfsd4_has_session(cstate));
	if (status)
		goto put_stateid;

	wake_up_var(d_inode(cstate->current_fh.fh_dentry));
	destroy_delegation(dp);
put_stateid:
	nfs4_put_stid(&dp->dl_stid);
out:
	return status;
}

/* last octet in a range */
static inline u64
last_byte_offset(u64 start, u64 len)
{
	u64 end;

	WARN_ON_ONCE(!len);
	end = start + len;
	return end > start ? end - 1: NFS4_MAX_UINT64;
}

/*
 * TODO: Linux file offsets are _signed_ 64-bit quantities, which means that
 * we can't properly handle lock requests that go beyond the (2^63 - 1)-th
 * byte, because of sign extension problems.  Since NFSv4 calls for 64-bit
 * locking, this prevents us from being completely protocol-compliant.  The
 * real solution to this problem is to start using unsigned file offsets in
 * the VFS, but this is a very deep change!
 */
static inline void
nfs4_transform_lock_offset(struct file_lock *lock)
{
	if (lock->fl_start < 0)
		lock->fl_start = OFFSET_MAX;
	if (lock->fl_end < 0)
		lock->fl_end = OFFSET_MAX;
}

static fl_owner_t
nfsd4_lm_get_owner(fl_owner_t owner)
{
	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)owner;

	nfs4_get_stateowner(&lo->lo_owner);
	return owner;
}

static void
nfsd4_lm_put_owner(fl_owner_t owner)
{
	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)owner;

	if (lo)
		nfs4_put_stateowner(&lo->lo_owner);
}

/* return pointer to struct nfs4_client if client is expirable */
static bool
nfsd4_lm_lock_expirable(struct file_lock *cfl)
{
	struct nfs4_lockowner *lo = (struct nfs4_lockowner *)cfl->fl_owner;
	struct nfs4_client *clp = lo->lo_owner.so_client;
	struct nfsd_net *nn;

	if (try_to_expire_client(clp)) {
		nn = net_generic(clp->net, nfsd_net_id);
		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
		return true;
	}
	return false;
}

/* schedule laundromat to run immediately and wait for it to complete */
static void
nfsd4_lm_expire_lock(void)
{
	flush_workqueue(laundry_wq);
}

static void
nfsd4_lm_notify(struct file_lock *fl)
{
	struct nfs4_lockowner		*lo = (struct nfs4_lockowner *)fl->fl_owner;
	struct net			*net = lo->lo_owner.so_client->net;
	struct nfsd_net			*nn = net_generic(net, nfsd_net_id);
	struct nfsd4_blocked_lock	*nbl = container_of(fl,
						struct nfsd4_blocked_lock, nbl_lock);
	bool queue = false;

	/* An empty list means that something else is going to be using it */
	spin_lock(&nn->blocked_locks_lock);
	if (!list_empty(&nbl->nbl_list)) {
		list_del_init(&nbl->nbl_list);
		list_del_init(&nbl->nbl_lru);
		queue = true;
	}
	spin_unlock(&nn->blocked_locks_lock);

	if (queue) {
		trace_nfsd_cb_notify_lock(lo, nbl);
		nfsd4_run_cb(&nbl->nbl_cb);
	}
}

static const struct lock_manager_operations nfsd_posix_mng_ops  = {
	.lm_mod_owner = THIS_MODULE,
	.lm_notify = nfsd4_lm_notify,
	.lm_get_owner = nfsd4_lm_get_owner,
	.lm_put_owner = nfsd4_lm_put_owner,
	.lm_lock_expirable = nfsd4_lm_lock_expirable,
	.lm_expire_lock = nfsd4_lm_expire_lock,
};

static inline void
nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny)
{
	struct nfs4_lockowner *lo;

	if (fl->fl_lmops == &nfsd_posix_mng_ops) {
		lo = (struct nfs4_lockowner *) fl->fl_owner;
		xdr_netobj_dup(&deny->ld_owner, &lo->lo_owner.so_owner,
						GFP_KERNEL);
		if (!deny->ld_owner.data)
			/* We just don't care that much */
			goto nevermind;
		deny->ld_clientid = lo->lo_owner.so_client->cl_clientid;
	} else {
nevermind:
		deny->ld_owner.len = 0;
		deny->ld_owner.data = NULL;
		deny->ld_clientid.cl_boot = 0;
		deny->ld_clientid.cl_id = 0;
	}
	deny->ld_start = fl->fl_start;
	deny->ld_length = NFS4_MAX_UINT64;
	if (fl->fl_end != NFS4_MAX_UINT64)
		deny->ld_length = fl->fl_end - fl->fl_start + 1;        
	deny->ld_type = NFS4_READ_LT;
	if (fl->fl_type != F_RDLCK)
		deny->ld_type = NFS4_WRITE_LT;
}

static struct nfs4_lockowner *
find_lockowner_str_locked(struct nfs4_client *clp, struct xdr_netobj *owner)
{
	unsigned int strhashval = ownerstr_hashval(owner);
	struct nfs4_stateowner *so;

	lockdep_assert_held(&clp->cl_lock);

	list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[strhashval],
			    so_strhash) {
		if (so->so_is_open_owner)
			continue;
		if (same_owner_str(so, owner))
			return lockowner(nfs4_get_stateowner(so));
	}
	return NULL;
}

static struct nfs4_lockowner *
find_lockowner_str(struct nfs4_client *clp, struct xdr_netobj *owner)
{
	struct nfs4_lockowner *lo;

	spin_lock(&clp->cl_lock);
	lo = find_lockowner_str_locked(clp, owner);
	spin_unlock(&clp->cl_lock);
	return lo;
}

static void nfs4_unhash_lockowner(struct nfs4_stateowner *sop)
{
	unhash_lockowner_locked(lockowner(sop));
}

static void nfs4_free_lockowner(struct nfs4_stateowner *sop)
{
	struct nfs4_lockowner *lo = lockowner(sop);

	kmem_cache_free(lockowner_slab, lo);
}

static const struct nfs4_stateowner_operations lockowner_ops = {
	.so_unhash =	nfs4_unhash_lockowner,
	.so_free =	nfs4_free_lockowner,
};

/*
 * Alloc a lock owner structure.
 * Called in nfsd4_lock - therefore, OPEN and OPEN_CONFIRM (if needed) has 
 * occurred. 
 *
 * strhashval = ownerstr_hashval
 */
static struct nfs4_lockowner *
alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp,
			   struct nfs4_ol_stateid *open_stp,
			   struct nfsd4_lock *lock)
{
	struct nfs4_lockowner *lo, *ret;

	lo = alloc_stateowner(lockowner_slab, &lock->lk_new_owner, clp);
	if (!lo)
		return NULL;
	INIT_LIST_HEAD(&lo->lo_blocked);
	INIT_LIST_HEAD(&lo->lo_owner.so_stateids);
	lo->lo_owner.so_is_open_owner = 0;
	lo->lo_owner.so_seqid = lock->lk_new_lock_seqid;
	lo->lo_owner.so_ops = &lockowner_ops;
	spin_lock(&clp->cl_lock);
	ret = find_lockowner_str_locked(clp, &lock->lk_new_owner);
	if (ret == NULL) {
		list_add(&lo->lo_owner.so_strhash,
			 &clp->cl_ownerstr_hashtbl[strhashval]);
		ret = lo;
	} else
		nfs4_free_stateowner(&lo->lo_owner);

	spin_unlock(&clp->cl_lock);
	return ret;
}

static struct nfs4_ol_stateid *
find_lock_stateid(const struct nfs4_lockowner *lo,
		  const struct nfs4_ol_stateid *ost)
{
	struct nfs4_ol_stateid *lst;

	lockdep_assert_held(&ost->st_stid.sc_client->cl_lock);

	/* If ost is not hashed, ost->st_locks will not be valid */
	if (!nfs4_ol_stateid_unhashed(ost))
		list_for_each_entry(lst, &ost->st_locks, st_locks) {
			if (lst->st_stateowner == &lo->lo_owner) {
				refcount_inc(&lst->st_stid.sc_count);
				return lst;
			}
		}
	return NULL;
}

static struct nfs4_ol_stateid *
init_lock_stateid(struct nfs4_ol_stateid *stp, struct nfs4_lockowner *lo,
		  struct nfs4_file *fp, struct inode *inode,
		  struct nfs4_ol_stateid *open_stp)
{
	struct nfs4_client *clp = lo->lo_owner.so_client;
	struct nfs4_ol_stateid *retstp;

	mutex_init(&stp->st_mutex);
	mutex_lock_nested(&stp->st_mutex, OPEN_STATEID_MUTEX);
retry:
	spin_lock(&clp->cl_lock);
	if (nfs4_ol_stateid_unhashed(open_stp))
		goto out_close;
	retstp = find_lock_stateid(lo, open_stp);
	if (retstp)
		goto out_found;
	refcount_inc(&stp->st_stid.sc_count);
	stp->st_stid.sc_type = NFS4_LOCK_STID;
	stp->st_stateowner = nfs4_get_stateowner(&lo->lo_owner);
	get_nfs4_file(fp);
	stp->st_stid.sc_file = fp;
	stp->st_access_bmap = 0;
	stp->st_deny_bmap = open_stp->st_deny_bmap;
	stp->st_openstp = open_stp;
	spin_lock(&fp->fi_lock);
	list_add(&stp->st_locks, &open_stp->st_locks);
	list_add(&stp->st_perstateowner, &lo->lo_owner.so_stateids);
	list_add(&stp->st_perfile, &fp->fi_stateids);
	spin_unlock(&fp->fi_lock);
	spin_unlock(&clp->cl_lock);
	return stp;
out_found:
	spin_unlock(&clp->cl_lock);
	if (nfsd4_lock_ol_stateid(retstp) != nfs_ok) {
		nfs4_put_stid(&retstp->st_stid);
		goto retry;
	}
	/* To keep mutex tracking happy */
	mutex_unlock(&stp->st_mutex);
	return retstp;
out_close:
	spin_unlock(&clp->cl_lock);
	mutex_unlock(&stp->st_mutex);
	return NULL;
}

static struct nfs4_ol_stateid *
find_or_create_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fi,
			    struct inode *inode, struct nfs4_ol_stateid *ost,
			    bool *new)
{
	struct nfs4_stid *ns = NULL;
	struct nfs4_ol_stateid *lst;
	struct nfs4_openowner *oo = openowner(ost->st_stateowner);
	struct nfs4_client *clp = oo->oo_owner.so_client;

	*new = false;
	spin_lock(&clp->cl_lock);
	lst = find_lock_stateid(lo, ost);
	spin_unlock(&clp->cl_lock);
	if (lst != NULL) {
		if (nfsd4_lock_ol_stateid(lst) == nfs_ok)
			goto out;
		nfs4_put_stid(&lst->st_stid);
	}
	ns = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_lock_stateid);
	if (ns == NULL)
		return NULL;

	lst = init_lock_stateid(openlockstateid(ns), lo, fi, inode, ost);
	if (lst == openlockstateid(ns))
		*new = true;
	else
		nfs4_put_stid(ns);
out:
	return lst;
}

static int
check_lock_length(u64 offset, u64 length)
{
	return ((length == 0) || ((length != NFS4_MAX_UINT64) &&
		(length > ~offset)));
}

static void get_lock_access(struct nfs4_ol_stateid *lock_stp, u32 access)
{
	struct nfs4_file *fp = lock_stp->st_stid.sc_file;

	lockdep_assert_held(&fp->fi_lock);

	if (test_access(access, lock_stp))
		return;
	__nfs4_file_get_access(fp, access);
	set_access(access, lock_stp);
}

static __be32
lookup_or_create_lock_state(struct nfsd4_compound_state *cstate,
			    struct nfs4_ol_stateid *ost,
			    struct nfsd4_lock *lock,
			    struct nfs4_ol_stateid **plst, bool *new)
{
	__be32 status;
	struct nfs4_file *fi = ost->st_stid.sc_file;
	struct nfs4_openowner *oo = openowner(ost->st_stateowner);
	struct nfs4_client *cl = oo->oo_owner.so_client;
	struct inode *inode = d_inode(cstate->current_fh.fh_dentry);
	struct nfs4_lockowner *lo;
	struct nfs4_ol_stateid *lst;
	unsigned int strhashval;

	lo = find_lockowner_str(cl, &lock->lk_new_owner);
	if (!lo) {
		strhashval = ownerstr_hashval(&lock->lk_new_owner);
		lo = alloc_init_lock_stateowner(strhashval, cl, ost, lock);
		if (lo == NULL)
			return nfserr_jukebox;
	} else {
		/* with an existing lockowner, seqids must be the same */
		status = nfserr_bad_seqid;
		if (!cstate->minorversion &&
		    lock->lk_new_lock_seqid != lo->lo_owner.so_seqid)
			goto out;
	}

	lst = find_or_create_lock_stateid(lo, fi, inode, ost, new);
	if (lst == NULL) {
		status = nfserr_jukebox;
		goto out;
	}

	status = nfs_ok;
	*plst = lst;
out:
	nfs4_put_stateowner(&lo->lo_owner);
	return status;
}

/*
 *  LOCK operation 
 */
__be32
nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
	   union nfsd4_op_u *u)
{
	struct nfsd4_lock *lock = &u->lock;
	struct nfs4_openowner *open_sop = NULL;
	struct nfs4_lockowner *lock_sop = NULL;
	struct nfs4_ol_stateid *lock_stp = NULL;
	struct nfs4_ol_stateid *open_stp = NULL;
	struct nfs4_file *fp;
	struct nfsd_file *nf = NULL;
	struct nfsd4_blocked_lock *nbl = NULL;
	struct file_lock *file_lock = NULL;
	struct file_lock *conflock = NULL;
	__be32 status = 0;
	int lkflg;
	int err;
	bool new = false;
	unsigned char fl_type;
	unsigned int fl_flags = FL_POSIX;
	struct net *net = SVC_NET(rqstp);
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	dprintk("NFSD: nfsd4_lock: start=%Ld length=%Ld\n",
		(long long) lock->lk_offset,
		(long long) lock->lk_length);

	if (check_lock_length(lock->lk_offset, lock->lk_length))
		 return nfserr_inval;

	if ((status = fh_verify(rqstp, &cstate->current_fh,
				S_IFREG, NFSD_MAY_LOCK))) {
		dprintk("NFSD: nfsd4_lock: permission denied!\n");
		return status;
	}

	if (lock->lk_is_new) {
		if (nfsd4_has_session(cstate))
			/* See rfc 5661 18.10.3: given clientid is ignored: */
			memcpy(&lock->lk_new_clientid,
				&cstate->clp->cl_clientid,
				sizeof(clientid_t));

		/* validate and update open stateid and open seqid */
		status = nfs4_preprocess_confirmed_seqid_op(cstate,
				        lock->lk_new_open_seqid,
		                        &lock->lk_new_open_stateid,
					&open_stp, nn);
		if (status)
			goto out;
		mutex_unlock(&open_stp->st_mutex);
		open_sop = openowner(open_stp->st_stateowner);
		status = nfserr_bad_stateid;
		if (!same_clid(&open_sop->oo_owner.so_client->cl_clientid,
						&lock->lk_new_clientid))
			goto out;
		status = lookup_or_create_lock_state(cstate, open_stp, lock,
							&lock_stp, &new);
	} else {
		status = nfs4_preprocess_seqid_op(cstate,
				       lock->lk_old_lock_seqid,
				       &lock->lk_old_lock_stateid,
				       NFS4_LOCK_STID, &lock_stp, nn);
	}
	if (status)
		goto out;
	lock_sop = lockowner(lock_stp->st_stateowner);

	lkflg = setlkflg(lock->lk_type);
	status = nfs4_check_openmode(lock_stp, lkflg);
	if (status)
		goto out;

	status = nfserr_grace;
	if (locks_in_grace(net) && !lock->lk_reclaim)
		goto out;
	status = nfserr_no_grace;
	if (!locks_in_grace(net) && lock->lk_reclaim)
		goto out;

	if (lock->lk_reclaim)
		fl_flags |= FL_RECLAIM;

	fp = lock_stp->st_stid.sc_file;
	switch (lock->lk_type) {
		case NFS4_READW_LT:
			if (nfsd4_has_session(cstate))
				fl_flags |= FL_SLEEP;
			fallthrough;
		case NFS4_READ_LT:
			spin_lock(&fp->fi_lock);
			nf = find_readable_file_locked(fp);
			if (nf)
				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_READ);
			spin_unlock(&fp->fi_lock);
			fl_type = F_RDLCK;
			break;
		case NFS4_WRITEW_LT:
			if (nfsd4_has_session(cstate))
				fl_flags |= FL_SLEEP;
			fallthrough;
		case NFS4_WRITE_LT:
			spin_lock(&fp->fi_lock);
			nf = find_writeable_file_locked(fp);
			if (nf)
				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_WRITE);
			spin_unlock(&fp->fi_lock);
			fl_type = F_WRLCK;
			break;
		default:
			status = nfserr_inval;
		goto out;
	}

	if (!nf) {
		status = nfserr_openmode;
		goto out;
	}

	/*
	 * Most filesystems with their own ->lock operations will block
	 * the nfsd thread waiting to acquire the lock.  That leads to
	 * deadlocks (we don't want every nfsd thread tied up waiting
	 * for file locks), so don't attempt blocking lock notifications
	 * on those filesystems:
	 */
	if (nf->nf_file->f_op->lock)
		fl_flags &= ~FL_SLEEP;

	nbl = find_or_allocate_block(lock_sop, &fp->fi_fhandle, nn);
	if (!nbl) {
		dprintk("NFSD: %s: unable to allocate block!\n", __func__);
		status = nfserr_jukebox;
		goto out;
	}

	file_lock = &nbl->nbl_lock;
	file_lock->fl_type = fl_type;
	file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(&lock_sop->lo_owner));
	file_lock->fl_pid = current->tgid;
	file_lock->fl_file = nf->nf_file;
	file_lock->fl_flags = fl_flags;
	file_lock->fl_lmops = &nfsd_posix_mng_ops;
	file_lock->fl_start = lock->lk_offset;
	file_lock->fl_end = last_byte_offset(lock->lk_offset, lock->lk_length);
	nfs4_transform_lock_offset(file_lock);

	conflock = locks_alloc_lock();
	if (!conflock) {
		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
		status = nfserr_jukebox;
		goto out;
	}

	if (fl_flags & FL_SLEEP) {
		nbl->nbl_time = ktime_get_boottime_seconds();
		spin_lock(&nn->blocked_locks_lock);
		list_add_tail(&nbl->nbl_list, &lock_sop->lo_blocked);
		list_add_tail(&nbl->nbl_lru, &nn->blocked_locks_lru);
		kref_get(&nbl->nbl_kref);
		spin_unlock(&nn->blocked_locks_lock);
	}

	err = vfs_lock_file(nf->nf_file, F_SETLK, file_lock, conflock);
	switch (err) {
	case 0: /* success! */
		nfs4_inc_and_copy_stateid(&lock->lk_resp_stateid, &lock_stp->st_stid);
		status = 0;
		if (lock->lk_reclaim)
			nn->somebody_reclaimed = true;
		break;
	case FILE_LOCK_DEFERRED:
		kref_put(&nbl->nbl_kref, free_nbl);
		nbl = NULL;
		fallthrough;
	case -EAGAIN:		/* conflock holds conflicting lock */
		status = nfserr_denied;
		dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
		nfs4_set_lock_denied(conflock, &lock->lk_denied);
		break;
	case -EDEADLK:
		status = nfserr_deadlock;
		break;
	default:
		dprintk("NFSD: nfsd4_lock: vfs_lock_file() failed! status %d\n",err);
		status = nfserrno(err);
		break;
	}
out:
	if (nbl) {
		/* dequeue it if we queued it before */
		if (fl_flags & FL_SLEEP) {
			spin_lock(&nn->blocked_locks_lock);
			if (!list_empty(&nbl->nbl_list) &&
			    !list_empty(&nbl->nbl_lru)) {
				list_del_init(&nbl->nbl_list);
				list_del_init(&nbl->nbl_lru);
				kref_put(&nbl->nbl_kref, free_nbl);
			}
			/* nbl can use one of lists to be linked to reaplist */
			spin_unlock(&nn->blocked_locks_lock);
		}
		free_blocked_lock(nbl);
	}
	if (nf)
		nfsd_file_put(nf);
	if (lock_stp) {
		/* Bump seqid manually if the 4.0 replay owner is openowner */
		if (cstate->replay_owner &&
		    cstate->replay_owner != &lock_sop->lo_owner &&
		    seqid_mutating_err(ntohl(status)))
			lock_sop->lo_owner.so_seqid++;

		/*
		 * If this is a new, never-before-used stateid, and we are
		 * returning an error, then just go ahead and release it.
		 */
		if (status && new)
			release_lock_stateid(lock_stp);

		mutex_unlock(&lock_stp->st_mutex);

		nfs4_put_stid(&lock_stp->st_stid);
	}
	if (open_stp)
		nfs4_put_stid(&open_stp->st_stid);
	nfsd4_bump_seqid(cstate, status);
	if (conflock)
		locks_free_lock(conflock);
	return status;
}

/*
 * The NFSv4 spec allows a client to do a LOCKT without holding an OPEN,
 * so we do a temporary open here just to get an open file to pass to
 * vfs_test_lock.
 */
static __be32 nfsd_test_lock(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file_lock *lock)
{
	struct nfsd_file *nf;
	struct inode *inode;
	__be32 err;

	err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
	if (err)
		return err;
	inode = fhp->fh_dentry->d_inode;
	inode_lock(inode); /* to block new leases till after test_lock: */
	err = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
	if (err)
		goto out;
	lock->fl_file = nf->nf_file;
	err = nfserrno(vfs_test_lock(nf->nf_file, lock));
	lock->fl_file = NULL;
out:
	inode_unlock(inode);
	nfsd_file_put(nf);
	return err;
}

/*
 * LOCKT operation
 */
__be32
nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
	    union nfsd4_op_u *u)
{
	struct nfsd4_lockt *lockt = &u->lockt;
	struct file_lock *file_lock = NULL;
	struct nfs4_lockowner *lo = NULL;
	__be32 status;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	if (locks_in_grace(SVC_NET(rqstp)))
		return nfserr_grace;

	if (check_lock_length(lockt->lt_offset, lockt->lt_length))
		 return nfserr_inval;

	if (!nfsd4_has_session(cstate)) {
		status = set_client(&lockt->lt_clientid, cstate, nn);
		if (status)
			goto out;
	}

	if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
		goto out;

	file_lock = locks_alloc_lock();
	if (!file_lock) {
		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
		status = nfserr_jukebox;
		goto out;
	}

	switch (lockt->lt_type) {
		case NFS4_READ_LT:
		case NFS4_READW_LT:
			file_lock->fl_type = F_RDLCK;
			break;
		case NFS4_WRITE_LT:
		case NFS4_WRITEW_LT:
			file_lock->fl_type = F_WRLCK;
			break;
		default:
			dprintk("NFSD: nfs4_lockt: bad lock type!\n");
			status = nfserr_inval;
			goto out;
	}

	lo = find_lockowner_str(cstate->clp, &lockt->lt_owner);
	if (lo)
		file_lock->fl_owner = (fl_owner_t)lo;
	file_lock->fl_pid = current->tgid;
	file_lock->fl_flags = FL_POSIX;

	file_lock->fl_start = lockt->lt_offset;
	file_lock->fl_end = last_byte_offset(lockt->lt_offset, lockt->lt_length);

	nfs4_transform_lock_offset(file_lock);

	status = nfsd_test_lock(rqstp, &cstate->current_fh, file_lock);
	if (status)
		goto out;

	if (file_lock->fl_type != F_UNLCK) {
		status = nfserr_denied;
		nfs4_set_lock_denied(file_lock, &lockt->lt_denied);
	}
out:
	if (lo)
		nfs4_put_stateowner(&lo->lo_owner);
	if (file_lock)
		locks_free_lock(file_lock);
	return status;
}

__be32
nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
	    union nfsd4_op_u *u)
{
	struct nfsd4_locku *locku = &u->locku;
	struct nfs4_ol_stateid *stp;
	struct nfsd_file *nf = NULL;
	struct file_lock *file_lock = NULL;
	__be32 status;
	int err;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

	dprintk("NFSD: nfsd4_locku: start=%Ld length=%Ld\n",
		(long long) locku->lu_offset,
		(long long) locku->lu_length);

	if (check_lock_length(locku->lu_offset, locku->lu_length))
		 return nfserr_inval;

	status = nfs4_preprocess_seqid_op(cstate, locku->lu_seqid,
					&locku->lu_stateid, NFS4_LOCK_STID,
					&stp, nn);
	if (status)
		goto out;
	nf = find_any_file(stp->st_stid.sc_file);
	if (!nf) {
		status = nfserr_lock_range;
		goto put_stateid;
	}
	file_lock = locks_alloc_lock();
	if (!file_lock) {
		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
		status = nfserr_jukebox;
		goto put_file;
	}

	file_lock->fl_type = F_UNLCK;
	file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(stp->st_stateowner));
	file_lock->fl_pid = current->tgid;
	file_lock->fl_file = nf->nf_file;
	file_lock->fl_flags = FL_POSIX;
	file_lock->fl_lmops = &nfsd_posix_mng_ops;
	file_lock->fl_start = locku->lu_offset;

	file_lock->fl_end = last_byte_offset(locku->lu_offset,
						locku->lu_length);
	nfs4_transform_lock_offset(file_lock);

	err = vfs_lock_file(nf->nf_file, F_SETLK, file_lock, NULL);
	if (err) {
		dprintk("NFSD: nfs4_locku: vfs_lock_file failed!\n");
		goto out_nfserr;
	}
	nfs4_inc_and_copy_stateid(&locku->lu_stateid, &stp->st_stid);
put_file:
	nfsd_file_put(nf);
put_stateid:
	mutex_unlock(&stp->st_mutex);
	nfs4_put_stid(&stp->st_stid);
out:
	nfsd4_bump_seqid(cstate, status);
	if (file_lock)
		locks_free_lock(file_lock);
	return status;

out_nfserr:
	status = nfserrno(err);
	goto put_file;
}

/*
 * returns
 * 	true:  locks held by lockowner
 * 	false: no locks held by lockowner
 */
static bool
check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
{
	struct file_lock *fl;
	int status = false;
	struct nfsd_file *nf = find_any_file(fp);
	struct inode *inode;
	struct file_lock_context *flctx;

	if (!nf) {
		/* Any valid lock stateid should have some sort of access */
		WARN_ON_ONCE(1);
		return status;
	}

	inode = locks_inode(nf->nf_file);
	flctx = inode->i_flctx;

	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
		spin_lock(&flctx->flc_lock);
		list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
			if (fl->fl_owner == (fl_owner_t)lowner) {
				status = true;
				break;
			}
		}
		spin_unlock(&flctx->flc_lock);
	}
	nfsd_file_put(nf);
	return status;
}

/**
 * nfsd4_release_lockowner - process NFSv4.0 RELEASE_LOCKOWNER operations
 * @rqstp: RPC transaction
 * @cstate: NFSv4 COMPOUND state
 * @u: RELEASE_LOCKOWNER arguments
 *
 * The lockowner's so_count is bumped when a lock record is added
 * or when copying a conflicting lock. The latter case is brief,
 * but can lead to fleeting false positives when looking for
 * locks-in-use.
 *
 * Return values:
 *   %nfs_ok: lockowner released or not found
 *   %nfserr_locks_held: lockowner still in use
 *   %nfserr_stale_clientid: clientid no longer active
 *   %nfserr_expired: clientid not recognized
 */
__be32
nfsd4_release_lockowner(struct svc_rqst *rqstp,
			struct nfsd4_compound_state *cstate,
			union nfsd4_op_u *u)
{
	struct nfsd4_release_lockowner *rlockowner = &u->release_lockowner;
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
	clientid_t *clid = &rlockowner->rl_clientid;
	struct nfs4_ol_stateid *stp;
	struct nfs4_lockowner *lo;
	struct nfs4_client *clp;
	LIST_HEAD(reaplist);
	__be32 status;

	dprintk("nfsd4_release_lockowner clientid: (%08x/%08x):\n",
		clid->cl_boot, clid->cl_id);

	status = set_client(clid, cstate, nn);
	if (status)
		return status;
	clp = cstate->clp;

	spin_lock(&clp->cl_lock);
	lo = find_lockowner_str_locked(clp, &rlockowner->rl_owner);
	if (!lo) {
		spin_unlock(&clp->cl_lock);
		return nfs_ok;
	}
	if (atomic_read(&lo->lo_owner.so_count) != 2) {
		spin_unlock(&clp->cl_lock);
		nfs4_put_stateowner(&lo->lo_owner);
		return nfserr_locks_held;
	}
	unhash_lockowner_locked(lo);
	while (!list_empty(&lo->lo_owner.so_stateids)) {
		stp = list_first_entry(&lo->lo_owner.so_stateids,
				       struct nfs4_ol_stateid,
				       st_perstateowner);
		WARN_ON(!unhash_lock_stateid(stp));
		put_ol_stateid_locked(stp, &reaplist);
	}
	spin_unlock(&clp->cl_lock);

	free_ol_stateid_reaplist(&reaplist);
	remove_blocked_locks(lo);
	nfs4_put_stateowner(&lo->lo_owner);
	return nfs_ok;
}

static inline struct nfs4_client_reclaim *
alloc_reclaim(void)
{
	return kmalloc(sizeof(struct nfs4_client_reclaim), GFP_KERNEL);
}

bool
nfs4_has_reclaimed_state(struct xdr_netobj name, struct nfsd_net *nn)
{
	struct nfs4_client_reclaim *crp;

	crp = nfsd4_find_reclaim_client(name, nn);
	return (crp && crp->cr_clp);
}

/*
 * failure => all reset bets are off, nfserr_no_grace...
 *
 * The caller is responsible for freeing name.data if NULL is returned (it
 * will be freed in nfs4_remove_reclaim_record in the normal case).
 */
struct nfs4_client_reclaim *
nfs4_client_to_reclaim(struct xdr_netobj name, struct xdr_netobj princhash,
		struct nfsd_net *nn)
{
	unsigned int strhashval;
	struct nfs4_client_reclaim *crp;

	crp = alloc_reclaim();
	if (crp) {
		strhashval = clientstr_hashval(name);
		INIT_LIST_HEAD(&crp->cr_strhash);
		list_add(&crp->cr_strhash, &nn->reclaim_str_hashtbl[strhashval]);
		crp->cr_name.data = name.data;
		crp->cr_name.len = name.len;
		crp->cr_princhash.data = princhash.data;
		crp->cr_princhash.len = princhash.len;
		crp->cr_clp = NULL;
		nn->reclaim_str_hashtbl_size++;
	}
	return crp;
}

void
nfs4_remove_reclaim_record(struct nfs4_client_reclaim *crp, struct nfsd_net *nn)
{
	list_del(&crp->cr_strhash);
	kfree(crp->cr_name.data);
	kfree(crp->cr_princhash.data);
	kfree(crp);
	nn->reclaim_str_hashtbl_size--;
}

void
nfs4_release_reclaim(struct nfsd_net *nn)
{
	struct nfs4_client_reclaim *crp = NULL;
	int i;

	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
		while (!list_empty(&nn->reclaim_str_hashtbl[i])) {
			crp = list_entry(nn->reclaim_str_hashtbl[i].next,
			                struct nfs4_client_reclaim, cr_strhash);
			nfs4_remove_reclaim_record(crp, nn);
		}
	}
	WARN_ON_ONCE(nn->reclaim_str_hashtbl_size);
}

/*
 * called from OPEN, CLAIM_PREVIOUS with a new clientid. */
struct nfs4_client_reclaim *
nfsd4_find_reclaim_client(struct xdr_netobj name, struct nfsd_net *nn)
{
	unsigned int strhashval;
	struct nfs4_client_reclaim *crp = NULL;

	strhashval = clientstr_hashval(name);
	list_for_each_entry(crp, &nn->reclaim_str_hashtbl[strhashval], cr_strhash) {
		if (compare_blob(&crp->cr_name, &name) == 0) {
			return crp;
		}
	}
	return NULL;
}

__be32
nfs4_check_open_reclaim(struct nfs4_client *clp)
{
	if (test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags))
		return nfserr_no_grace;

	if (nfsd4_client_record_check(clp))
		return nfserr_reclaim_bad;

	return nfs_ok;
}

/*
 * Since the lifetime of a delegation isn't limited to that of an open, a
 * client may quite reasonably hang on to a delegation as long as it has
 * the inode cached.  This becomes an obvious problem the first time a
 * client's inode cache approaches the size of the server's total memory.
 *
 * For now we avoid this problem by imposing a hard limit on the number
 * of delegations, which varies according to the server's memory size.
 */
static void
set_max_delegations(void)
{
	/*
	 * Allow at most 4 delegations per megabyte of RAM.  Quick
	 * estimates suggest that in the worst case (where every delegation
	 * is for a different inode), a delegation could take about 1.5K,
	 * giving a worst case usage of about 6% of memory.
	 */
	max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT);
}

static int nfs4_state_create_net(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	int i;

	nn->conf_id_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
					    sizeof(struct list_head),
					    GFP_KERNEL);
	if (!nn->conf_id_hashtbl)
		goto err;
	nn->unconf_id_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
					      sizeof(struct list_head),
					      GFP_KERNEL);
	if (!nn->unconf_id_hashtbl)
		goto err_unconf_id;
	nn->sessionid_hashtbl = kmalloc_array(SESSION_HASH_SIZE,
					      sizeof(struct list_head),
					      GFP_KERNEL);
	if (!nn->sessionid_hashtbl)
		goto err_sessionid;

	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
		INIT_LIST_HEAD(&nn->conf_id_hashtbl[i]);
		INIT_LIST_HEAD(&nn->unconf_id_hashtbl[i]);
	}
	for (i = 0; i < SESSION_HASH_SIZE; i++)
		INIT_LIST_HEAD(&nn->sessionid_hashtbl[i]);
	nn->conf_name_tree = RB_ROOT;
	nn->unconf_name_tree = RB_ROOT;
	nn->boot_time = ktime_get_real_seconds();
	nn->grace_ended = false;
	nn->nfsd4_manager.block_opens = true;
	INIT_LIST_HEAD(&nn->nfsd4_manager.list);
	INIT_LIST_HEAD(&nn->client_lru);
	INIT_LIST_HEAD(&nn->close_lru);
	INIT_LIST_HEAD(&nn->del_recall_lru);
	spin_lock_init(&nn->client_lock);
	spin_lock_init(&nn->s2s_cp_lock);
	idr_init(&nn->s2s_cp_stateids);

	spin_lock_init(&nn->blocked_locks_lock);
	INIT_LIST_HEAD(&nn->blocked_locks_lru);

	INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main);
	INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, courtesy_client_reaper);
	get_net(net);

	return 0;

err_sessionid:
	kfree(nn->unconf_id_hashtbl);
err_unconf_id:
	kfree(nn->conf_id_hashtbl);
err:
	return -ENOMEM;
}

static void
nfs4_state_destroy_net(struct net *net)
{
	int i;
	struct nfs4_client *clp = NULL;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
		while (!list_empty(&nn->conf_id_hashtbl[i])) {
			clp = list_entry(nn->conf_id_hashtbl[i].next, struct nfs4_client, cl_idhash);
			destroy_client(clp);
		}
	}

	WARN_ON(!list_empty(&nn->blocked_locks_lru));

	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
		while (!list_empty(&nn->unconf_id_hashtbl[i])) {
			clp = list_entry(nn->unconf_id_hashtbl[i].next, struct nfs4_client, cl_idhash);
			destroy_client(clp);
		}
	}

	kfree(nn->sessionid_hashtbl);
	kfree(nn->unconf_id_hashtbl);
	kfree(nn->conf_id_hashtbl);
	put_net(net);
}

int
nfs4_state_start_net(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	int ret;

	ret = nfs4_state_create_net(net);
	if (ret)
		return ret;
	locks_start_grace(net, &nn->nfsd4_manager);
	nfsd4_client_tracking_init(net);
	if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0)
		goto skip_grace;
	printk(KERN_INFO "NFSD: starting %lld-second grace period (net %x)\n",
	       nn->nfsd4_grace, net->ns.inum);
	trace_nfsd_grace_start(nn);
	queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_grace * HZ);
	return 0;

skip_grace:
	printk(KERN_INFO "NFSD: no clients to reclaim, skipping NFSv4 grace period (net %x)\n",
			net->ns.inum);
	queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_lease * HZ);
	nfsd4_end_grace(nn);
	return 0;
}

/* initialization to perform when the nfsd service is started: */

int
nfs4_state_start(void)
{
	int ret;

	ret = nfsd4_create_callback_queue();
	if (ret)
		return ret;

	set_max_delegations();
	return 0;
}

void
nfs4_state_shutdown_net(struct net *net)
{
	struct nfs4_delegation *dp = NULL;
	struct list_head *pos, *next, reaplist;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	cancel_delayed_work_sync(&nn->laundromat_work);
	locks_end_grace(&nn->nfsd4_manager);

	INIT_LIST_HEAD(&reaplist);
	spin_lock(&state_lock);
	list_for_each_safe(pos, next, &nn->del_recall_lru) {
		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
		WARN_ON(!unhash_delegation_locked(dp));
		list_add(&dp->dl_recall_lru, &reaplist);
	}
	spin_unlock(&state_lock);
	list_for_each_safe(pos, next, &reaplist) {
		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
		list_del_init(&dp->dl_recall_lru);
		destroy_unhashed_deleg(dp);
	}

	nfsd4_client_tracking_exit(net);
	nfs4_state_destroy_net(net);
#ifdef CONFIG_NFSD_V4_2_INTER_SSC
	nfsd4_ssc_shutdown_umount(nn);
#endif
}

void
nfs4_state_shutdown(void)
{
	nfsd4_destroy_callback_queue();
}

static void
get_stateid(struct nfsd4_compound_state *cstate, stateid_t *stateid)
{
	if (HAS_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG) &&
	    CURRENT_STATEID(stateid))
		memcpy(stateid, &cstate->current_stateid, sizeof(stateid_t));
}

static void
put_stateid(struct nfsd4_compound_state *cstate, stateid_t *stateid)
{
	if (cstate->minorversion) {
		memcpy(&cstate->current_stateid, stateid, sizeof(stateid_t));
		SET_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG);
	}
}

void
clear_current_stateid(struct nfsd4_compound_state *cstate)
{
	CLEAR_CSTATE_FLAG(cstate, CURRENT_STATE_ID_FLAG);
}

/*
 * functions to set current state id
 */
void
nfsd4_set_opendowngradestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	put_stateid(cstate, &u->open_downgrade.od_stateid);
}

void
nfsd4_set_openstateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	put_stateid(cstate, &u->open.op_stateid);
}

void
nfsd4_set_closestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	put_stateid(cstate, &u->close.cl_stateid);
}

void
nfsd4_set_lockstateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	put_stateid(cstate, &u->lock.lk_resp_stateid);
}

/*
 * functions to consume current state id
 */

void
nfsd4_get_opendowngradestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->open_downgrade.od_stateid);
}

void
nfsd4_get_delegreturnstateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->delegreturn.dr_stateid);
}

void
nfsd4_get_freestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->free_stateid.fr_stateid);
}

void
nfsd4_get_setattrstateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->setattr.sa_stateid);
}

void
nfsd4_get_closestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->close.cl_stateid);
}

void
nfsd4_get_lockustateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->locku.lu_stateid);
}

void
nfsd4_get_readstateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->read.rd_stateid);
}

void
nfsd4_get_writestateid(struct nfsd4_compound_state *cstate,
		union nfsd4_op_u *u)
{
	get_stateid(cstate, &u->write.wr_stateid);
}