summaryrefslogtreecommitdiff
path: root/drivers/md/dm-raid.c
blob: cab12b2251bac21c2717912d7228132e4860b821 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
/*
 * Copyright (C) 2010-2011 Neil Brown
 * Copyright (C) 2010-2018 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the GPL.
 */

#include <linux/slab.h>
#include <linux/module.h>

#include "md.h"
#include "raid1.h"
#include "raid5.h"
#include "raid10.h"
#include "md-bitmap.h"

#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "raid"
#define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */

/*
 * Minimum sectors of free reshape space per raid device
 */
#define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)

/*
 * Minimum journal space 4 MiB in sectors.
 */
#define	MIN_RAID456_JOURNAL_SPACE (4*2048)

static bool devices_handle_discard_safely = false;

/*
 * The following flags are used by dm-raid.c to set up the array state.
 * They must be cleared before md_run is called.
 */
#define FirstUse 10		/* rdev flag */

struct raid_dev {
	/*
	 * Two DM devices, one to hold metadata and one to hold the
	 * actual data/parity.	The reason for this is to not confuse
	 * ti->len and give more flexibility in altering size and
	 * characteristics.
	 *
	 * While it is possible for this device to be associated
	 * with a different physical device than the data_dev, it
	 * is intended for it to be the same.
	 *    |--------- Physical Device ---------|
	 *    |- meta_dev -|------ data_dev ------|
	 */
	struct dm_dev *meta_dev;
	struct dm_dev *data_dev;
	struct md_rdev rdev;
};

/*
 * Bits for establishing rs->ctr_flags
 *
 * 1 = no flag value
 * 2 = flag with value
 */
#define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
#define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
#define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
#define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
#define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
#define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
#define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
#define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
#define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
#define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
#define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
#define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
/* New for v1.9.0 */
#define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
#define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
#define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */

/* New for v1.10.0 */
#define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */

/* New for v1.11.1 */
#define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */

/*
 * Flags for rs->ctr_flags field.
 */
#define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
#define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
#define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
#define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
#define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
#define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
#define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
#define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
#define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
#define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
#define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
#define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
#define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
#define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
#define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
#define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
#define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)

/*
 * Definitions of various constructor flags to
 * be used in checks of valid / invalid flags
 * per raid level.
 */
/* Define all any sync flags */
#define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)

/* Define flags for options without argument (e.g. 'nosync') */
#define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
					 CTR_FLAG_RAID10_USE_NEAR_SETS)

/* Define flags for options with one argument (e.g. 'delta_disks +2') */
#define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
				  CTR_FLAG_WRITE_MOSTLY | \
				  CTR_FLAG_DAEMON_SLEEP | \
				  CTR_FLAG_MIN_RECOVERY_RATE | \
				  CTR_FLAG_MAX_RECOVERY_RATE | \
				  CTR_FLAG_MAX_WRITE_BEHIND | \
				  CTR_FLAG_STRIPE_CACHE | \
				  CTR_FLAG_REGION_SIZE | \
				  CTR_FLAG_RAID10_COPIES | \
				  CTR_FLAG_RAID10_FORMAT | \
				  CTR_FLAG_DELTA_DISKS | \
				  CTR_FLAG_DATA_OFFSET | \
				  CTR_FLAG_JOURNAL_DEV | \
				  CTR_FLAG_JOURNAL_MODE)

/* Valid options definitions per raid level... */

/* "raid0" does only accept data offset */
#define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)

/* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
#define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
				 CTR_FLAG_REBUILD | \
				 CTR_FLAG_WRITE_MOSTLY | \
				 CTR_FLAG_DAEMON_SLEEP | \
				 CTR_FLAG_MIN_RECOVERY_RATE | \
				 CTR_FLAG_MAX_RECOVERY_RATE | \
				 CTR_FLAG_MAX_WRITE_BEHIND | \
				 CTR_FLAG_REGION_SIZE | \
				 CTR_FLAG_DELTA_DISKS | \
				 CTR_FLAG_DATA_OFFSET)

/* "raid10" does not accept any raid1 or stripe cache options */
#define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
				 CTR_FLAG_REBUILD | \
				 CTR_FLAG_DAEMON_SLEEP | \
				 CTR_FLAG_MIN_RECOVERY_RATE | \
				 CTR_FLAG_MAX_RECOVERY_RATE | \
				 CTR_FLAG_REGION_SIZE | \
				 CTR_FLAG_RAID10_COPIES | \
				 CTR_FLAG_RAID10_FORMAT | \
				 CTR_FLAG_DELTA_DISKS | \
				 CTR_FLAG_DATA_OFFSET | \
				 CTR_FLAG_RAID10_USE_NEAR_SETS)

/*
 * "raid4/5/6" do not accept any raid1 or raid10 specific options
 *
 * "raid6" does not accept "nosync", because it is not guaranteed
 * that both parity and q-syndrome are being written properly with
 * any writes
 */
#define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
				 CTR_FLAG_REBUILD | \
				 CTR_FLAG_DAEMON_SLEEP | \
				 CTR_FLAG_MIN_RECOVERY_RATE | \
				 CTR_FLAG_MAX_RECOVERY_RATE | \
				 CTR_FLAG_STRIPE_CACHE | \
				 CTR_FLAG_REGION_SIZE | \
				 CTR_FLAG_DELTA_DISKS | \
				 CTR_FLAG_DATA_OFFSET | \
				 CTR_FLAG_JOURNAL_DEV | \
				 CTR_FLAG_JOURNAL_MODE)

#define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
				 CTR_FLAG_REBUILD | \
				 CTR_FLAG_DAEMON_SLEEP | \
				 CTR_FLAG_MIN_RECOVERY_RATE | \
				 CTR_FLAG_MAX_RECOVERY_RATE | \
				 CTR_FLAG_STRIPE_CACHE | \
				 CTR_FLAG_REGION_SIZE | \
				 CTR_FLAG_DELTA_DISKS | \
				 CTR_FLAG_DATA_OFFSET | \
				 CTR_FLAG_JOURNAL_DEV | \
				 CTR_FLAG_JOURNAL_MODE)
/* ...valid options definitions per raid level */

/*
 * Flags for rs->runtime_flags field
 * (RT_FLAG prefix meaning "runtime flag")
 *
 * These are all internal and used to define runtime state,
 * e.g. to prevent another resume from preresume processing
 * the raid set all over again.
 */
#define RT_FLAG_RS_PRERESUMED		0
#define RT_FLAG_RS_RESUMED		1
#define RT_FLAG_RS_BITMAP_LOADED	2
#define RT_FLAG_UPDATE_SBS		3
#define RT_FLAG_RESHAPE_RS		4
#define RT_FLAG_RS_SUSPENDED		5
#define RT_FLAG_RS_IN_SYNC		6
#define RT_FLAG_RS_RESYNCING		7
#define RT_FLAG_RS_GROW			8

/* Array elements of 64 bit needed for rebuild/failed disk bits */
#define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)

/*
 * raid set level, layout and chunk sectors backup/restore
 */
struct rs_layout {
	int new_level;
	int new_layout;
	int new_chunk_sectors;
};

struct raid_set {
	struct dm_target *ti;

	uint32_t stripe_cache_entries;
	unsigned long ctr_flags;
	unsigned long runtime_flags;

	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];

	int raid_disks;
	int delta_disks;
	int data_offset;
	int raid10_copies;
	int requested_bitmap_chunk_sectors;

	struct mddev md;
	struct raid_type *raid_type;

	sector_t array_sectors;
	sector_t dev_sectors;

	/* Optional raid4/5/6 journal device */
	struct journal_dev {
		struct dm_dev *dev;
		struct md_rdev rdev;
		int mode;
	} journal_dev;

	struct raid_dev dev[];
};

static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
{
	struct mddev *mddev = &rs->md;

	l->new_level = mddev->new_level;
	l->new_layout = mddev->new_layout;
	l->new_chunk_sectors = mddev->new_chunk_sectors;
}

static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
{
	struct mddev *mddev = &rs->md;

	mddev->new_level = l->new_level;
	mddev->new_layout = l->new_layout;
	mddev->new_chunk_sectors = l->new_chunk_sectors;
}

/* raid10 algorithms (i.e. formats) */
#define	ALGORITHM_RAID10_DEFAULT	0
#define	ALGORITHM_RAID10_NEAR		1
#define	ALGORITHM_RAID10_OFFSET		2
#define	ALGORITHM_RAID10_FAR		3

/* Supported raid types and properties. */
static struct raid_type {
	const char *name;		/* RAID algorithm. */
	const char *descr;		/* Descriptor text for logging. */
	const unsigned int parity_devs;	/* # of parity devices. */
	const unsigned int minimal_devs;/* minimal # of devices in set. */
	const unsigned int level;	/* RAID level. */
	const unsigned int algorithm;	/* RAID algorithm. */
} raid_types[] = {
	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
};

/* True, if @v is in inclusive range [@min, @max] */
static bool __within_range(long v, long min, long max)
{
	return v >= min && v <= max;
}

/* All table line arguments are defined here */
static struct arg_name_flag {
	const unsigned long flag;
	const char *name;
} __arg_name_flags[] = {
	{ CTR_FLAG_SYNC, "sync"},
	{ CTR_FLAG_NOSYNC, "nosync"},
	{ CTR_FLAG_REBUILD, "rebuild"},
	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
	{ CTR_FLAG_REGION_SIZE, "region_size"},
	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
};

/* Return argument name string for given @flag */
static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
{
	if (hweight32(flag) == 1) {
		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);

		while (anf-- > __arg_name_flags)
			if (flag & anf->flag)
				return anf->name;

	} else
		DMERR("%s called with more than one flag!", __func__);

	return NULL;
}

/* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
static struct {
	const int mode;
	const char *param;
} _raid456_journal_mode[] = {
	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
};

/* Return MD raid4/5/6 journal mode for dm @journal_mode one */
static int dm_raid_journal_mode_to_md(const char *mode)
{
	int m = ARRAY_SIZE(_raid456_journal_mode);

	while (m--)
		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
			return _raid456_journal_mode[m].mode;

	return -EINVAL;
}

/* Return dm-raid raid4/5/6 journal mode string for @mode */
static const char *md_journal_mode_to_dm_raid(const int mode)
{
	int m = ARRAY_SIZE(_raid456_journal_mode);

	while (m--)
		if (mode == _raid456_journal_mode[m].mode)
			return _raid456_journal_mode[m].param;

	return "unknown";
}

/*
 * Bool helpers to test for various raid levels of a raid set.
 * It's level as reported by the superblock rather than
 * the requested raid_type passed to the constructor.
 */
/* Return true, if raid set in @rs is raid0 */
static bool rs_is_raid0(struct raid_set *rs)
{
	return !rs->md.level;
}

/* Return true, if raid set in @rs is raid1 */
static bool rs_is_raid1(struct raid_set *rs)
{
	return rs->md.level == 1;
}

/* Return true, if raid set in @rs is raid10 */
static bool rs_is_raid10(struct raid_set *rs)
{
	return rs->md.level == 10;
}

/* Return true, if raid set in @rs is level 6 */
static bool rs_is_raid6(struct raid_set *rs)
{
	return rs->md.level == 6;
}

/* Return true, if raid set in @rs is level 4, 5 or 6 */
static bool rs_is_raid456(struct raid_set *rs)
{
	return __within_range(rs->md.level, 4, 6);
}

/* Return true, if raid set in @rs is reshapable */
static bool __is_raid10_far(int layout);
static bool rs_is_reshapable(struct raid_set *rs)
{
	return rs_is_raid456(rs) ||
	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
}

/* Return true, if raid set in @rs is recovering */
static bool rs_is_recovering(struct raid_set *rs)
{
	return rs->md.recovery_cp < rs->md.dev_sectors;
}

/* Return true, if raid set in @rs is reshaping */
static bool rs_is_reshaping(struct raid_set *rs)
{
	return rs->md.reshape_position != MaxSector;
}

/*
 * bool helpers to test for various raid levels of a raid type @rt
 */

/* Return true, if raid type in @rt is raid0 */
static bool rt_is_raid0(struct raid_type *rt)
{
	return !rt->level;
}

/* Return true, if raid type in @rt is raid1 */
static bool rt_is_raid1(struct raid_type *rt)
{
	return rt->level == 1;
}

/* Return true, if raid type in @rt is raid10 */
static bool rt_is_raid10(struct raid_type *rt)
{
	return rt->level == 10;
}

/* Return true, if raid type in @rt is raid4/5 */
static bool rt_is_raid45(struct raid_type *rt)
{
	return __within_range(rt->level, 4, 5);
}

/* Return true, if raid type in @rt is raid6 */
static bool rt_is_raid6(struct raid_type *rt)
{
	return rt->level == 6;
}

/* Return true, if raid type in @rt is raid4/5/6 */
static bool rt_is_raid456(struct raid_type *rt)
{
	return __within_range(rt->level, 4, 6);
}
/* END: raid level bools */

/* Return valid ctr flags for the raid level of @rs */
static unsigned long __valid_flags(struct raid_set *rs)
{
	if (rt_is_raid0(rs->raid_type))
		return RAID0_VALID_FLAGS;
	else if (rt_is_raid1(rs->raid_type))
		return RAID1_VALID_FLAGS;
	else if (rt_is_raid10(rs->raid_type))
		return RAID10_VALID_FLAGS;
	else if (rt_is_raid45(rs->raid_type))
		return RAID45_VALID_FLAGS;
	else if (rt_is_raid6(rs->raid_type))
		return RAID6_VALID_FLAGS;

	return 0;
}

/*
 * Check for valid flags set on @rs
 *
 * Has to be called after parsing of the ctr flags!
 */
static int rs_check_for_valid_flags(struct raid_set *rs)
{
	if (rs->ctr_flags & ~__valid_flags(rs)) {
		rs->ti->error = "Invalid flags combination";
		return -EINVAL;
	}

	return 0;
}

/* MD raid10 bit definitions and helpers */
#define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
#define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
#define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
#define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */

/* Return md raid10 near copies for @layout */
static unsigned int __raid10_near_copies(int layout)
{
	return layout & 0xFF;
}

/* Return md raid10 far copies for @layout */
static unsigned int __raid10_far_copies(int layout)
{
	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
}

/* Return true if md raid10 offset for @layout */
static bool __is_raid10_offset(int layout)
{
	return !!(layout & RAID10_OFFSET);
}

/* Return true if md raid10 near for @layout */
static bool __is_raid10_near(int layout)
{
	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
}

/* Return true if md raid10 far for @layout */
static bool __is_raid10_far(int layout)
{
	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
}

/* Return md raid10 layout string for @layout */
static const char *raid10_md_layout_to_format(int layout)
{
	/*
	 * Bit 16 stands for "offset"
	 * (i.e. adjacent stripes hold copies)
	 *
	 * Refer to MD's raid10.c for details
	 */
	if (__is_raid10_offset(layout))
		return "offset";

	if (__raid10_near_copies(layout) > 1)
		return "near";

	if (__raid10_far_copies(layout) > 1)
		return "far";

	return "unknown";
}

/* Return md raid10 algorithm for @name */
static int raid10_name_to_format(const char *name)
{
	if (!strcasecmp(name, "near"))
		return ALGORITHM_RAID10_NEAR;
	else if (!strcasecmp(name, "offset"))
		return ALGORITHM_RAID10_OFFSET;
	else if (!strcasecmp(name, "far"))
		return ALGORITHM_RAID10_FAR;

	return -EINVAL;
}

/* Return md raid10 copies for @layout */
static unsigned int raid10_md_layout_to_copies(int layout)
{
	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
}

/* Return md raid10 format id for @format string */
static int raid10_format_to_md_layout(struct raid_set *rs,
				      unsigned int algorithm,
				      unsigned int copies)
{
	unsigned int n = 1, f = 1, r = 0;

	/*
	 * MD resilienece flaw:
	 *
	 * enabling use_far_sets for far/offset formats causes copies
	 * to be colocated on the same devs together with their origins!
	 *
	 * -> disable it for now in the definition above
	 */
	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
	    algorithm == ALGORITHM_RAID10_NEAR)
		n = copies;

	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
		f = copies;
		r = RAID10_OFFSET;
		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
			r |= RAID10_USE_FAR_SETS;

	} else if (algorithm == ALGORITHM_RAID10_FAR) {
		f = copies;
		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
			r |= RAID10_USE_FAR_SETS;

	} else
		return -EINVAL;

	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
}
/* END: MD raid10 bit definitions and helpers */

/* Check for any of the raid10 algorithms */
static bool __got_raid10(struct raid_type *rtp, const int layout)
{
	if (rtp->level == 10) {
		switch (rtp->algorithm) {
		case ALGORITHM_RAID10_DEFAULT:
		case ALGORITHM_RAID10_NEAR:
			return __is_raid10_near(layout);
		case ALGORITHM_RAID10_OFFSET:
			return __is_raid10_offset(layout);
		case ALGORITHM_RAID10_FAR:
			return __is_raid10_far(layout);
		default:
			break;
		}
	}

	return false;
}

/* Return raid_type for @name */
static struct raid_type *get_raid_type(const char *name)
{
	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);

	while (rtp-- > raid_types)
		if (!strcasecmp(rtp->name, name))
			return rtp;

	return NULL;
}

/* Return raid_type for @name based derived from @level and @layout */
static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
{
	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);

	while (rtp-- > raid_types) {
		/* RAID10 special checks based on @layout flags/properties */
		if (rtp->level == level &&
		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
			return rtp;
	}

	return NULL;
}

/* Adjust rdev sectors */
static void rs_set_rdev_sectors(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;
	struct md_rdev *rdev;

	/*
	 * raid10 sets rdev->sector to the device size, which
	 * is unintended in case of out-of-place reshaping
	 */
	rdev_for_each(rdev, mddev)
		if (!test_bit(Journal, &rdev->flags))
			rdev->sectors = mddev->dev_sectors;
}

/*
 * Change bdev capacity of @rs in case of a disk add/remove reshape
 */
static void rs_set_capacity(struct raid_set *rs)
{
	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));

	set_capacity_and_notify(gendisk, rs->md.array_sectors);
}

/*
 * Set the mddev properties in @rs to the current
 * ones retrieved from the freshest superblock
 */
static void rs_set_cur(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;

	mddev->new_level = mddev->level;
	mddev->new_layout = mddev->layout;
	mddev->new_chunk_sectors = mddev->chunk_sectors;
}

/*
 * Set the mddev properties in @rs to the new
 * ones requested by the ctr
 */
static void rs_set_new(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;

	mddev->level = mddev->new_level;
	mddev->layout = mddev->new_layout;
	mddev->chunk_sectors = mddev->new_chunk_sectors;
	mddev->raid_disks = rs->raid_disks;
	mddev->delta_disks = 0;
}

static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
				       unsigned int raid_devs)
{
	unsigned int i;
	struct raid_set *rs;

	if (raid_devs <= raid_type->parity_devs) {
		ti->error = "Insufficient number of devices";
		return ERR_PTR(-EINVAL);
	}

	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
	if (!rs) {
		ti->error = "Cannot allocate raid context";
		return ERR_PTR(-ENOMEM);
	}

	mddev_init(&rs->md);

	rs->raid_disks = raid_devs;
	rs->delta_disks = 0;

	rs->ti = ti;
	rs->raid_type = raid_type;
	rs->stripe_cache_entries = 256;
	rs->md.raid_disks = raid_devs;
	rs->md.level = raid_type->level;
	rs->md.new_level = rs->md.level;
	rs->md.layout = raid_type->algorithm;
	rs->md.new_layout = rs->md.layout;
	rs->md.delta_disks = 0;
	rs->md.recovery_cp = MaxSector;

	for (i = 0; i < raid_devs; i++)
		md_rdev_init(&rs->dev[i].rdev);

	/*
	 * Remaining items to be initialized by further RAID params:
	 *  rs->md.persistent
	 *  rs->md.external
	 *  rs->md.chunk_sectors
	 *  rs->md.new_chunk_sectors
	 *  rs->md.dev_sectors
	 */

	return rs;
}

/* Free all @rs allocations */
static void raid_set_free(struct raid_set *rs)
{
	int i;

	if (rs->journal_dev.dev) {
		md_rdev_clear(&rs->journal_dev.rdev);
		dm_put_device(rs->ti, rs->journal_dev.dev);
	}

	for (i = 0; i < rs->raid_disks; i++) {
		if (rs->dev[i].meta_dev)
			dm_put_device(rs->ti, rs->dev[i].meta_dev);
		md_rdev_clear(&rs->dev[i].rdev);
		if (rs->dev[i].data_dev)
			dm_put_device(rs->ti, rs->dev[i].data_dev);
	}

	kfree(rs);
}

/*
 * For every device we have two words
 *  <meta_dev>: meta device name or '-' if missing
 *  <data_dev>: data device name or '-' if missing
 *
 * The following are permitted:
 *    - -
 *    - <data_dev>
 *    <meta_dev> <data_dev>
 *
 * The following is not allowed:
 *    <meta_dev> -
 *
 * This code parses those words.  If there is a failure,
 * the caller must use raid_set_free() to unwind the operations.
 */
static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
{
	int i;
	int rebuild = 0;
	int metadata_available = 0;
	int r = 0;
	const char *arg;

	/* Put off the number of raid devices argument to get to dev pairs */
	arg = dm_shift_arg(as);
	if (!arg)
		return -EINVAL;

	for (i = 0; i < rs->raid_disks; i++) {
		rs->dev[i].rdev.raid_disk = i;

		rs->dev[i].meta_dev = NULL;
		rs->dev[i].data_dev = NULL;

		/*
		 * There are no offsets initially.
		 * Out of place reshape will set them accordingly.
		 */
		rs->dev[i].rdev.data_offset = 0;
		rs->dev[i].rdev.new_data_offset = 0;
		rs->dev[i].rdev.mddev = &rs->md;

		arg = dm_shift_arg(as);
		if (!arg)
			return -EINVAL;

		if (strcmp(arg, "-")) {
			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
					  &rs->dev[i].meta_dev);
			if (r) {
				rs->ti->error = "RAID metadata device lookup failure";
				return r;
			}

			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
			if (!rs->dev[i].rdev.sb_page) {
				rs->ti->error = "Failed to allocate superblock page";
				return -ENOMEM;
			}
		}

		arg = dm_shift_arg(as);
		if (!arg)
			return -EINVAL;

		if (!strcmp(arg, "-")) {
			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
			    (!rs->dev[i].rdev.recovery_offset)) {
				rs->ti->error = "Drive designated for rebuild not specified";
				return -EINVAL;
			}

			if (rs->dev[i].meta_dev) {
				rs->ti->error = "No data device supplied with metadata device";
				return -EINVAL;
			}

			continue;
		}

		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
				  &rs->dev[i].data_dev);
		if (r) {
			rs->ti->error = "RAID device lookup failure";
			return r;
		}

		if (rs->dev[i].meta_dev) {
			metadata_available = 1;
			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
		}
		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
			rebuild++;
	}

	if (rs->journal_dev.dev)
		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);

	if (metadata_available) {
		rs->md.external = 0;
		rs->md.persistent = 1;
		rs->md.major_version = 2;
	} else if (rebuild && !rs->md.recovery_cp) {
		/*
		 * Without metadata, we will not be able to tell if the array
		 * is in-sync or not - we must assume it is not.  Therefore,
		 * it is impossible to rebuild a drive.
		 *
		 * Even if there is metadata, the on-disk information may
		 * indicate that the array is not in-sync and it will then
		 * fail at that time.
		 *
		 * User could specify 'nosync' option if desperate.
		 */
		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
		return -EINVAL;
	}

	return 0;
}

/*
 * validate_region_size
 * @rs
 * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
 *
 * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
 * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
 *
 * Returns: 0 on success, -EINVAL on failure.
 */
static int validate_region_size(struct raid_set *rs, unsigned long region_size)
{
	unsigned long min_region_size = rs->ti->len / (1 << 21);

	if (rs_is_raid0(rs))
		return 0;

	if (!region_size) {
		/*
		 * Choose a reasonable default.	 All figures in sectors.
		 */
		if (min_region_size > (1 << 13)) {
			/* If not a power of 2, make it the next power of 2 */
			region_size = roundup_pow_of_two(min_region_size);
			DMINFO("Choosing default region size of %lu sectors",
			       region_size);
		} else {
			DMINFO("Choosing default region size of 4MiB");
			region_size = 1 << 13; /* sectors */
		}
	} else {
		/*
		 * Validate user-supplied value.
		 */
		if (region_size > rs->ti->len) {
			rs->ti->error = "Supplied region size is too large";
			return -EINVAL;
		}

		if (region_size < min_region_size) {
			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
			      region_size, min_region_size);
			rs->ti->error = "Supplied region size is too small";
			return -EINVAL;
		}

		if (!is_power_of_2(region_size)) {
			rs->ti->error = "Region size is not a power of 2";
			return -EINVAL;
		}

		if (region_size < rs->md.chunk_sectors) {
			rs->ti->error = "Region size is smaller than the chunk size";
			return -EINVAL;
		}
	}

	/*
	 * Convert sectors to bytes.
	 */
	rs->md.bitmap_info.chunksize = to_bytes(region_size);

	return 0;
}

/*
 * validate_raid_redundancy
 * @rs
 *
 * Determine if there are enough devices in the array that haven't
 * failed (or are being rebuilt) to form a usable array.
 *
 * Returns: 0 on success, -EINVAL on failure.
 */
static int validate_raid_redundancy(struct raid_set *rs)
{
	unsigned int i, rebuild_cnt = 0;
	unsigned int rebuilds_per_group = 0, copies;
	unsigned int group_size, last_group_start;

	for (i = 0; i < rs->md.raid_disks; i++)
		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
		    !rs->dev[i].rdev.sb_page)
			rebuild_cnt++;

	switch (rs->md.level) {
	case 0:
		break;
	case 1:
		if (rebuild_cnt >= rs->md.raid_disks)
			goto too_many;
		break;
	case 4:
	case 5:
	case 6:
		if (rebuild_cnt > rs->raid_type->parity_devs)
			goto too_many;
		break;
	case 10:
		copies = raid10_md_layout_to_copies(rs->md.new_layout);
		if (copies < 2) {
			DMERR("Bogus raid10 data copies < 2!");
			return -EINVAL;
		}

		if (rebuild_cnt < copies)
			break;

		/*
		 * It is possible to have a higher rebuild count for RAID10,
		 * as long as the failed devices occur in different mirror
		 * groups (i.e. different stripes).
		 *
		 * When checking "near" format, make sure no adjacent devices
		 * have failed beyond what can be handled.  In addition to the
		 * simple case where the number of devices is a multiple of the
		 * number of copies, we must also handle cases where the number
		 * of devices is not a multiple of the number of copies.
		 * E.g.	   dev1 dev2 dev3 dev4 dev5
		 *	    A	 A    B	   B	C
		 *	    C	 D    D	   E	E
		 */
		if (__is_raid10_near(rs->md.new_layout)) {
			for (i = 0; i < rs->md.raid_disks; i++) {
				if (!(i % copies))
					rebuilds_per_group = 0;
				if ((!rs->dev[i].rdev.sb_page ||
				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
				    (++rebuilds_per_group >= copies))
					goto too_many;
			}
			break;
		}

		/*
		 * When checking "far" and "offset" formats, we need to ensure
		 * that the device that holds its copy is not also dead or
		 * being rebuilt.  (Note that "far" and "offset" formats only
		 * support two copies right now.  These formats also only ever
		 * use the 'use_far_sets' variant.)
		 *
		 * This check is somewhat complicated by the need to account
		 * for arrays that are not a multiple of (far) copies.	This
		 * results in the need to treat the last (potentially larger)
		 * set differently.
		 */
		group_size = (rs->md.raid_disks / copies);
		last_group_start = (rs->md.raid_disks / group_size) - 1;
		last_group_start *= group_size;
		for (i = 0; i < rs->md.raid_disks; i++) {
			if (!(i % copies) && !(i > last_group_start))
				rebuilds_per_group = 0;
			if ((!rs->dev[i].rdev.sb_page ||
			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
			    (++rebuilds_per_group >= copies))
					goto too_many;
		}
		break;
	default:
		if (rebuild_cnt)
			return -EINVAL;
	}

	return 0;

too_many:
	return -EINVAL;
}

/*
 * Possible arguments are...
 *	<chunk_size> [optional_args]
 *
 * Argument definitions
 *    <chunk_size>			The number of sectors per disk that
 *					will form the "stripe"
 *    [[no]sync]			Force or prevent recovery of the
 *					entire array
 *    [rebuild <idx>]			Rebuild the drive indicated by the index
 *    [daemon_sleep <ms>]		Time between bitmap daemon work to
 *					clear bits
 *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
 *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
 *    [write_mostly <idx>]		Indicate a write mostly drive via index
 *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
 *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
 *    [region_size <sectors>]		Defines granularity of bitmap
 *    [journal_dev <dev>]		raid4/5/6 journaling deviice
 *    					(i.e. write hole closing log)
 *
 * RAID10-only options:
 *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
 *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
 */
static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
			     unsigned int num_raid_params)
{
	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
	unsigned int raid10_copies = 2;
	unsigned int i, write_mostly = 0;
	unsigned int region_size = 0;
	sector_t max_io_len;
	const char *arg, *key;
	struct raid_dev *rd;
	struct raid_type *rt = rs->raid_type;

	arg = dm_shift_arg(as);
	num_raid_params--; /* Account for chunk_size argument */

	if (kstrtoint(arg, 10, &value) < 0) {
		rs->ti->error = "Bad numerical argument given for chunk_size";
		return -EINVAL;
	}

	/*
	 * First, parse the in-order required arguments
	 * "chunk_size" is the only argument of this type.
	 */
	if (rt_is_raid1(rt)) {
		if (value)
			DMERR("Ignoring chunk size parameter for RAID 1");
		value = 0;
	} else if (!is_power_of_2(value)) {
		rs->ti->error = "Chunk size must be a power of 2";
		return -EINVAL;
	} else if (value < 8) {
		rs->ti->error = "Chunk size value is too small";
		return -EINVAL;
	}

	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;

	/*
	 * We set each individual device as In_sync with a completed
	 * 'recovery_offset'.  If there has been a device failure or
	 * replacement then one of the following cases applies:
	 *
	 *   1) User specifies 'rebuild'.
	 *	- Device is reset when param is read.
	 *   2) A new device is supplied.
	 *	- No matching superblock found, resets device.
	 *   3) Device failure was transient and returns on reload.
	 *	- Failure noticed, resets device for bitmap replay.
	 *   4) Device hadn't completed recovery after previous failure.
	 *	- Superblock is read and overrides recovery_offset.
	 *
	 * What is found in the superblocks of the devices is always
	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
	 */
	for (i = 0; i < rs->raid_disks; i++) {
		set_bit(In_sync, &rs->dev[i].rdev.flags);
		rs->dev[i].rdev.recovery_offset = MaxSector;
	}

	/*
	 * Second, parse the unordered optional arguments
	 */
	for (i = 0; i < num_raid_params; i++) {
		key = dm_shift_arg(as);
		if (!key) {
			rs->ti->error = "Not enough raid parameters given";
			return -EINVAL;
		}

		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
				rs->ti->error = "Only one 'nosync' argument allowed";
				return -EINVAL;
			}
			continue;
		}
		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
				rs->ti->error = "Only one 'sync' argument allowed";
				return -EINVAL;
			}
			continue;
		}
		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
				return -EINVAL;
			}
			continue;
		}

		arg = dm_shift_arg(as);
		i++; /* Account for the argument pairs */
		if (!arg) {
			rs->ti->error = "Wrong number of raid parameters given";
			return -EINVAL;
		}

		/*
		 * Parameters that take a string value are checked here.
		 */
		/* "raid10_format {near|offset|far} */
		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
				return -EINVAL;
			}
			if (!rt_is_raid10(rt)) {
				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
				return -EINVAL;
			}
			raid10_format = raid10_name_to_format(arg);
			if (raid10_format < 0) {
				rs->ti->error = "Invalid 'raid10_format' value given";
				return raid10_format;
			}
			continue;
		}

		/* "journal_dev <dev>" */
		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
			int r;
			struct md_rdev *jdev;

			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
				return -EINVAL;
			}
			if (!rt_is_raid456(rt)) {
				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
				return -EINVAL;
			}
			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
					  &rs->journal_dev.dev);
			if (r) {
				rs->ti->error = "raid4/5/6 journal device lookup failure";
				return r;
			}
			jdev = &rs->journal_dev.rdev;
			md_rdev_init(jdev);
			jdev->mddev = &rs->md;
			jdev->bdev = rs->journal_dev.dev->bdev;
			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
				rs->ti->error = "No space for raid4/5/6 journal";
				return -ENOSPC;
			}
			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
			set_bit(Journal, &jdev->flags);
			continue;
		}

		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
			int r;

			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
				return -EINVAL;
			}
			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
				return -EINVAL;
			}
			r = dm_raid_journal_mode_to_md(arg);
			if (r < 0) {
				rs->ti->error = "Invalid 'journal_mode' argument";
				return r;
			}
			rs->journal_dev.mode = r;
			continue;
		}

		/*
		 * Parameters with number values from here on.
		 */
		if (kstrtoint(arg, 10, &value) < 0) {
			rs->ti->error = "Bad numerical argument given in raid params";
			return -EINVAL;
		}

		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
			/*
			 * "rebuild" is being passed in by userspace to provide
			 * indexes of replaced devices and to set up additional
			 * devices on raid level takeover.
			 */
			if (!__within_range(value, 0, rs->raid_disks - 1)) {
				rs->ti->error = "Invalid rebuild index given";
				return -EINVAL;
			}

			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
				rs->ti->error = "rebuild for this index already given";
				return -EINVAL;
			}

			rd = rs->dev + value;
			clear_bit(In_sync, &rd->rdev.flags);
			clear_bit(Faulty, &rd->rdev.flags);
			rd->rdev.recovery_offset = 0;
			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
			if (!rt_is_raid1(rt)) {
				rs->ti->error = "write_mostly option is only valid for RAID1";
				return -EINVAL;
			}

			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
				rs->ti->error = "Invalid write_mostly index given";
				return -EINVAL;
			}

			write_mostly++;
			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
			if (!rt_is_raid1(rt)) {
				rs->ti->error = "max_write_behind option is only valid for RAID1";
				return -EINVAL;
			}

			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
				rs->ti->error = "Only one max_write_behind argument pair allowed";
				return -EINVAL;
			}

			/*
			 * In device-mapper, we specify things in sectors, but
			 * MD records this value in kB
			 */
			if (value < 0 || value / 2 > COUNTER_MAX) {
				rs->ti->error = "Max write-behind limit out of range";
				return -EINVAL;
			}

			rs->md.bitmap_info.max_write_behind = value / 2;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
				rs->ti->error = "Only one daemon_sleep argument pair allowed";
				return -EINVAL;
			}
			if (value < 0) {
				rs->ti->error = "daemon sleep period out of range";
				return -EINVAL;
			}
			rs->md.bitmap_info.daemon_sleep = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
			/* Userspace passes new data_offset after having extended the the data image LV */
			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
				rs->ti->error = "Only one data_offset argument pair allowed";
				return -EINVAL;
			}
			/* Ensure sensible data offset */
			if (value < 0 ||
			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
				rs->ti->error = "Bogus data_offset value";
				return -EINVAL;
			}
			rs->data_offset = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
			/* Define the +/-# of disks to add to/remove from the given raid set */
			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
				rs->ti->error = "Only one delta_disks argument pair allowed";
				return -EINVAL;
			}
			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
				rs->ti->error = "Too many delta_disk requested";
				return -EINVAL;
			}

			rs->delta_disks = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
				rs->ti->error = "Only one stripe_cache argument pair allowed";
				return -EINVAL;
			}

			if (!rt_is_raid456(rt)) {
				rs->ti->error = "Inappropriate argument: stripe_cache";
				return -EINVAL;
			}

			if (value < 0) {
				rs->ti->error = "Bogus stripe cache entries value";
				return -EINVAL;
			}
			rs->stripe_cache_entries = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
				return -EINVAL;
			}

			if (value < 0) {
				rs->ti->error = "min_recovery_rate out of range";
				return -EINVAL;
			}
			rs->md.sync_speed_min = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
				return -EINVAL;
			}

			if (value < 0) {
				rs->ti->error = "max_recovery_rate out of range";
				return -EINVAL;
			}
			rs->md.sync_speed_max = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
				rs->ti->error = "Only one region_size argument pair allowed";
				return -EINVAL;
			}

			region_size = value;
			rs->requested_bitmap_chunk_sectors = value;
		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
				rs->ti->error = "Only one raid10_copies argument pair allowed";
				return -EINVAL;
			}

			if (!__within_range(value, 2, rs->md.raid_disks)) {
				rs->ti->error = "Bad value for 'raid10_copies'";
				return -EINVAL;
			}

			raid10_copies = value;
		} else {
			DMERR("Unable to parse RAID parameter: %s", key);
			rs->ti->error = "Unable to parse RAID parameter";
			return -EINVAL;
		}
	}

	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
		rs->ti->error = "sync and nosync are mutually exclusive";
		return -EINVAL;
	}

	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
		return -EINVAL;
	}

	if (write_mostly >= rs->md.raid_disks) {
		rs->ti->error = "Can't set all raid1 devices to write_mostly";
		return -EINVAL;
	}

	if (rs->md.sync_speed_max &&
	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
		rs->ti->error = "Bogus recovery rates";
		return -EINVAL;
	}

	if (validate_region_size(rs, region_size))
		return -EINVAL;

	if (rs->md.chunk_sectors)
		max_io_len = rs->md.chunk_sectors;
	else
		max_io_len = region_size;

	if (dm_set_target_max_io_len(rs->ti, max_io_len))
		return -EINVAL;

	if (rt_is_raid10(rt)) {
		if (raid10_copies > rs->md.raid_disks) {
			rs->ti->error = "Not enough devices to satisfy specification";
			return -EINVAL;
		}

		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
		if (rs->md.new_layout < 0) {
			rs->ti->error = "Error getting raid10 format";
			return rs->md.new_layout;
		}

		rt = get_raid_type_by_ll(10, rs->md.new_layout);
		if (!rt) {
			rs->ti->error = "Failed to recognize new raid10 layout";
			return -EINVAL;
		}

		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
			return -EINVAL;
		}
	}

	rs->raid10_copies = raid10_copies;

	/* Assume there are no metadata devices until the drives are parsed */
	rs->md.persistent = 0;
	rs->md.external = 1;

	/* Check, if any invalid ctr arguments have been passed in for the raid level */
	return rs_check_for_valid_flags(rs);
}

/* Set raid4/5/6 cache size */
static int rs_set_raid456_stripe_cache(struct raid_set *rs)
{
	int r;
	struct r5conf *conf;
	struct mddev *mddev = &rs->md;
	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
	uint32_t nr_stripes = rs->stripe_cache_entries;

	if (!rt_is_raid456(rs->raid_type)) {
		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
		return -EINVAL;
	}

	if (nr_stripes < min_stripes) {
		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
		       nr_stripes, min_stripes);
		nr_stripes = min_stripes;
	}

	conf = mddev->private;
	if (!conf) {
		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
		return -EINVAL;
	}

	/* Try setting number of stripes in raid456 stripe cache */
	if (conf->min_nr_stripes != nr_stripes) {
		r = raid5_set_cache_size(mddev, nr_stripes);
		if (r) {
			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
			return r;
		}

		DMINFO("%u stripe cache entries", nr_stripes);
	}

	return 0;
}

/* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
static unsigned int mddev_data_stripes(struct raid_set *rs)
{
	return rs->md.raid_disks - rs->raid_type->parity_devs;
}

/* Return # of data stripes of @rs (i.e. as of ctr) */
static unsigned int rs_data_stripes(struct raid_set *rs)
{
	return rs->raid_disks - rs->raid_type->parity_devs;
}

/*
 * Retrieve rdev->sectors from any valid raid device of @rs
 * to allow userpace to pass in arbitray "- -" device tupples.
 */
static sector_t __rdev_sectors(struct raid_set *rs)
{
	int i;

	for (i = 0; i < rs->md.raid_disks; i++) {
		struct md_rdev *rdev = &rs->dev[i].rdev;

		if (!test_bit(Journal, &rdev->flags) &&
		    rdev->bdev && rdev->sectors)
			return rdev->sectors;
	}

	return 0;
}

/* Check that calculated dev_sectors fits all component devices. */
static int _check_data_dev_sectors(struct raid_set *rs)
{
	sector_t ds = ~0;
	struct md_rdev *rdev;

	rdev_for_each(rdev, &rs->md)
		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
			ds = min(ds, to_sector(i_size_read(rdev->bdev->bd_inode)));
			if (ds < rs->md.dev_sectors) {
				rs->ti->error = "Component device(s) too small";
				return -EINVAL;
			}
		}

	return 0;
}

/* Calculate the sectors per device and per array used for @rs */
static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
{
	int delta_disks;
	unsigned int data_stripes;
	sector_t array_sectors = sectors, dev_sectors = sectors;
	struct mddev *mddev = &rs->md;

	if (use_mddev) {
		delta_disks = mddev->delta_disks;
		data_stripes = mddev_data_stripes(rs);
	} else {
		delta_disks = rs->delta_disks;
		data_stripes = rs_data_stripes(rs);
	}

	/* Special raid1 case w/o delta_disks support (yet) */
	if (rt_is_raid1(rs->raid_type))
		;
	else if (rt_is_raid10(rs->raid_type)) {
		if (rs->raid10_copies < 2 ||
		    delta_disks < 0) {
			rs->ti->error = "Bogus raid10 data copies or delta disks";
			return -EINVAL;
		}

		dev_sectors *= rs->raid10_copies;
		if (sector_div(dev_sectors, data_stripes))
			goto bad;

		array_sectors = (data_stripes + delta_disks) * dev_sectors;
		if (sector_div(array_sectors, rs->raid10_copies))
			goto bad;

	} else if (sector_div(dev_sectors, data_stripes))
		goto bad;

	else
		/* Striped layouts */
		array_sectors = (data_stripes + delta_disks) * dev_sectors;

	mddev->array_sectors = array_sectors;
	mddev->dev_sectors = dev_sectors;
	rs_set_rdev_sectors(rs);

	return _check_data_dev_sectors(rs);
bad:
	rs->ti->error = "Target length not divisible by number of data devices";
	return -EINVAL;
}

/* Setup recovery on @rs */
static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
{
	/* raid0 does not recover */
	if (rs_is_raid0(rs))
		rs->md.recovery_cp = MaxSector;
	/*
	 * A raid6 set has to be recovered either
	 * completely or for the grown part to
	 * ensure proper parity and Q-Syndrome
	 */
	else if (rs_is_raid6(rs))
		rs->md.recovery_cp = dev_sectors;
	/*
	 * Other raid set types may skip recovery
	 * depending on the 'nosync' flag.
	 */
	else
		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
				     ? MaxSector : dev_sectors;
}

static void do_table_event(struct work_struct *ws)
{
	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);

	smp_rmb(); /* Make sure we access most actual mddev properties */
	if (!rs_is_reshaping(rs)) {
		if (rs_is_raid10(rs))
			rs_set_rdev_sectors(rs);
		rs_set_capacity(rs);
	}
	dm_table_event(rs->ti->table);
}

/*
 * Make sure a valid takover (level switch) is being requested on @rs
 *
 * Conversions of raid sets from one MD personality to another
 * have to conform to restrictions which are enforced here.
 */
static int rs_check_takeover(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;
	unsigned int near_copies;

	if (rs->md.degraded) {
		rs->ti->error = "Can't takeover degraded raid set";
		return -EPERM;
	}

	if (rs_is_reshaping(rs)) {
		rs->ti->error = "Can't takeover reshaping raid set";
		return -EPERM;
	}

	switch (mddev->level) {
	case 0:
		/* raid0 -> raid1/5 with one disk */
		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
		    mddev->raid_disks == 1)
			return 0;

		/* raid0 -> raid10 */
		if (mddev->new_level == 10 &&
		    !(rs->raid_disks % mddev->raid_disks))
			return 0;

		/* raid0 with multiple disks -> raid4/5/6 */
		if (__within_range(mddev->new_level, 4, 6) &&
		    mddev->new_layout == ALGORITHM_PARITY_N &&
		    mddev->raid_disks > 1)
			return 0;

		break;

	case 10:
		/* Can't takeover raid10_offset! */
		if (__is_raid10_offset(mddev->layout))
			break;

		near_copies = __raid10_near_copies(mddev->layout);

		/* raid10* -> raid0 */
		if (mddev->new_level == 0) {
			/* Can takeover raid10_near with raid disks divisable by data copies! */
			if (near_copies > 1 &&
			    !(mddev->raid_disks % near_copies)) {
				mddev->raid_disks /= near_copies;
				mddev->delta_disks = mddev->raid_disks;
				return 0;
			}

			/* Can takeover raid10_far */
			if (near_copies == 1 &&
			    __raid10_far_copies(mddev->layout) > 1)
				return 0;

			break;
		}

		/* raid10_{near,far} -> raid1 */
		if (mddev->new_level == 1 &&
		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
			return 0;

		/* raid10_{near,far} with 2 disks -> raid4/5 */
		if (__within_range(mddev->new_level, 4, 5) &&
		    mddev->raid_disks == 2)
			return 0;
		break;

	case 1:
		/* raid1 with 2 disks -> raid4/5 */
		if (__within_range(mddev->new_level, 4, 5) &&
		    mddev->raid_disks == 2) {
			mddev->degraded = 1;
			return 0;
		}

		/* raid1 -> raid0 */
		if (mddev->new_level == 0 &&
		    mddev->raid_disks == 1)
			return 0;

		/* raid1 -> raid10 */
		if (mddev->new_level == 10)
			return 0;
		break;

	case 4:
		/* raid4 -> raid0 */
		if (mddev->new_level == 0)
			return 0;

		/* raid4 -> raid1/5 with 2 disks */
		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
		    mddev->raid_disks == 2)
			return 0;

		/* raid4 -> raid5/6 with parity N */
		if (__within_range(mddev->new_level, 5, 6) &&
		    mddev->layout == ALGORITHM_PARITY_N)
			return 0;
		break;

	case 5:
		/* raid5 with parity N -> raid0 */
		if (mddev->new_level == 0 &&
		    mddev->layout == ALGORITHM_PARITY_N)
			return 0;

		/* raid5 with parity N -> raid4 */
		if (mddev->new_level == 4 &&
		    mddev->layout == ALGORITHM_PARITY_N)
			return 0;

		/* raid5 with 2 disks -> raid1/4/10 */
		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
		    mddev->raid_disks == 2)
			return 0;

		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
		if (mddev->new_level == 6 &&
		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
			return 0;
		break;

	case 6:
		/* raid6 with parity N -> raid0 */
		if (mddev->new_level == 0 &&
		    mddev->layout == ALGORITHM_PARITY_N)
			return 0;

		/* raid6 with parity N -> raid4 */
		if (mddev->new_level == 4 &&
		    mddev->layout == ALGORITHM_PARITY_N)
			return 0;

		/* raid6_*_n with Q-Syndrome N -> raid5_* */
		if (mddev->new_level == 5 &&
		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
			return 0;

	default:
		break;
	}

	rs->ti->error = "takeover not possible";
	return -EINVAL;
}

/* True if @rs requested to be taken over */
static bool rs_takeover_requested(struct raid_set *rs)
{
	return rs->md.new_level != rs->md.level;
}

/* True if @rs is requested to reshape by ctr */
static bool rs_reshape_requested(struct raid_set *rs)
{
	bool change;
	struct mddev *mddev = &rs->md;

	if (rs_takeover_requested(rs))
		return false;

	if (rs_is_raid0(rs))
		return false;

	change = mddev->new_layout != mddev->layout ||
		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
		 rs->delta_disks;

	/* Historical case to support raid1 reshape without delta disks */
	if (rs_is_raid1(rs)) {
		if (rs->delta_disks)
			return !!rs->delta_disks;

		return !change &&
		       mddev->raid_disks != rs->raid_disks;
	}

	if (rs_is_raid10(rs))
		return change &&
		       !__is_raid10_far(mddev->new_layout) &&
		       rs->delta_disks >= 0;

	return change;
}

/*  Features */
#define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */

/* State flags for sb->flags */
#define	SB_FLAG_RESHAPE_ACTIVE		0x1
#define	SB_FLAG_RESHAPE_BACKWARDS	0x2

/*
 * This structure is never routinely used by userspace, unlike md superblocks.
 * Devices with this superblock should only ever be accessed via device-mapper.
 */
#define DM_RAID_MAGIC 0x64526D44
struct dm_raid_superblock {
	__le32 magic;		/* "DmRd" */
	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */

	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
	__le32 array_position;	/* The position of this drive in the raid set */

	__le64 events;		/* Incremented by md when superblock updated */
	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
				/* indicate failures (see extension below) */

	/*
	 * This offset tracks the progress of the repair or replacement of
	 * an individual drive.
	 */
	__le64 disk_recovery_offset;

	/*
	 * This offset tracks the progress of the initial raid set
	 * synchronisation/parity calculation.
	 */
	__le64 array_resync_offset;

	/*
	 * raid characteristics
	 */
	__le32 level;
	__le32 layout;
	__le32 stripe_sectors;

	/********************************************************************
	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
	 *
	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
	 */

	__le32 flags; /* Flags defining array states for reshaping */

	/*
	 * This offset tracks the progress of a raid
	 * set reshape in order to be able to restart it
	 */
	__le64 reshape_position;

	/*
	 * These define the properties of the array in case of an interrupted reshape
	 */
	__le32 new_level;
	__le32 new_layout;
	__le32 new_stripe_sectors;
	__le32 delta_disks;

	__le64 array_sectors; /* Array size in sectors */

	/*
	 * Sector offsets to data on devices (reshaping).
	 * Needed to support out of place reshaping, thus
	 * not writing over any stripes whilst converting
	 * them from old to new layout
	 */
	__le64 data_offset;
	__le64 new_data_offset;

	__le64 sectors; /* Used device size in sectors */

	/*
	 * Additonal Bit field of devices indicating failures to support
	 * up to 256 devices with the 1.9.0 on-disk metadata format
	 */
	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];

	__le32 incompat_features;	/* Used to indicate any incompatible features */

	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
} __packed;

/*
 * Check for reshape constraints on raid set @rs:
 *
 * - reshape function non-existent
 * - degraded set
 * - ongoing recovery
 * - ongoing reshape
 *
 * Returns 0 if none or -EPERM if given constraint
 * and error message reference in @errmsg
 */
static int rs_check_reshape(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;

	if (!mddev->pers || !mddev->pers->check_reshape)
		rs->ti->error = "Reshape not supported";
	else if (mddev->degraded)
		rs->ti->error = "Can't reshape degraded raid set";
	else if (rs_is_recovering(rs))
		rs->ti->error = "Convert request on recovering raid set prohibited";
	else if (rs_is_reshaping(rs))
		rs->ti->error = "raid set already reshaping!";
	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
	else
		return 0;

	return -EPERM;
}

static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
{
	BUG_ON(!rdev->sb_page);

	if (rdev->sb_loaded && !force_reload)
		return 0;

	rdev->sb_loaded = 0;

	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
		DMERR("Failed to read superblock of device at position %d",
		      rdev->raid_disk);
		md_error(rdev->mddev, rdev);
		set_bit(Faulty, &rdev->flags);
		return -EIO;
	}

	rdev->sb_loaded = 1;

	return 0;
}

static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
{
	failed_devices[0] = le64_to_cpu(sb->failed_devices);
	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));

	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
		int i = ARRAY_SIZE(sb->extended_failed_devices);

		while (i--)
			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
	}
}

static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
{
	int i = ARRAY_SIZE(sb->extended_failed_devices);

	sb->failed_devices = cpu_to_le64(failed_devices[0]);
	while (i--)
		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
}

/*
 * Synchronize the superblock members with the raid set properties
 *
 * All superblock data is little endian.
 */
static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
{
	bool update_failed_devices = false;
	unsigned int i;
	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
	struct dm_raid_superblock *sb;
	struct raid_set *rs = container_of(mddev, struct raid_set, md);

	/* No metadata device, no superblock */
	if (!rdev->meta_bdev)
		return;

	BUG_ON(!rdev->sb_page);

	sb = page_address(rdev->sb_page);

	sb_retrieve_failed_devices(sb, failed_devices);

	for (i = 0; i < rs->raid_disks; i++)
		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
			update_failed_devices = true;
			set_bit(i, (void *) failed_devices);
		}

	if (update_failed_devices)
		sb_update_failed_devices(sb, failed_devices);

	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);

	sb->num_devices = cpu_to_le32(mddev->raid_disks);
	sb->array_position = cpu_to_le32(rdev->raid_disk);

	sb->events = cpu_to_le64(mddev->events);

	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);

	sb->level = cpu_to_le32(mddev->level);
	sb->layout = cpu_to_le32(mddev->layout);
	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);

	/********************************************************************
	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
	 *
	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
	 */
	sb->new_level = cpu_to_le32(mddev->new_level);
	sb->new_layout = cpu_to_le32(mddev->new_layout);
	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);

	sb->delta_disks = cpu_to_le32(mddev->delta_disks);

	smp_rmb(); /* Make sure we access most recent reshape position */
	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
		/* Flag ongoing reshape */
		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);

		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
	} else {
		/* Clear reshape flags */
		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
	}

	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
	sb->data_offset = cpu_to_le64(rdev->data_offset);
	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
	sb->sectors = cpu_to_le64(rdev->sectors);
	sb->incompat_features = cpu_to_le32(0);

	/* Zero out the rest of the payload after the size of the superblock */
	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
}

/*
 * super_load
 *
 * This function creates a superblock if one is not found on the device
 * and will decide which superblock to use if there's a choice.
 *
 * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
 */
static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
{
	int r;
	struct dm_raid_superblock *sb;
	struct dm_raid_superblock *refsb;
	uint64_t events_sb, events_refsb;

	r = read_disk_sb(rdev, rdev->sb_size, false);
	if (r)
		return r;

	sb = page_address(rdev->sb_page);

	/*
	 * Two cases that we want to write new superblocks and rebuild:
	 * 1) New device (no matching magic number)
	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
	 */
	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
		super_sync(rdev->mddev, rdev);

		set_bit(FirstUse, &rdev->flags);
		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);

		/* Force writing of superblocks to disk */
		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);

		/* Any superblock is better than none, choose that if given */
		return refdev ? 0 : 1;
	}

	if (!refdev)
		return 1;

	events_sb = le64_to_cpu(sb->events);

	refsb = page_address(refdev->sb_page);
	events_refsb = le64_to_cpu(refsb->events);

	return (events_sb > events_refsb) ? 1 : 0;
}

static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
{
	int role;
	unsigned int d;
	struct mddev *mddev = &rs->md;
	uint64_t events_sb;
	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
	struct dm_raid_superblock *sb;
	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
	struct md_rdev *r;
	struct dm_raid_superblock *sb2;

	sb = page_address(rdev->sb_page);
	events_sb = le64_to_cpu(sb->events);

	/*
	 * Initialise to 1 if this is a new superblock.
	 */
	mddev->events = events_sb ? : 1;

	mddev->reshape_position = MaxSector;

	mddev->raid_disks = le32_to_cpu(sb->num_devices);
	mddev->level = le32_to_cpu(sb->level);
	mddev->layout = le32_to_cpu(sb->layout);
	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);

	/*
	 * Reshaping is supported, e.g. reshape_position is valid
	 * in superblock and superblock content is authoritative.
	 */
	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
		/* Superblock is authoritative wrt given raid set layout! */
		mddev->new_level = le32_to_cpu(sb->new_level);
		mddev->new_layout = le32_to_cpu(sb->new_layout);
		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
		mddev->array_sectors = le64_to_cpu(sb->array_sectors);

		/* raid was reshaping and got interrupted */
		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
				DMERR("Reshape requested but raid set is still reshaping");
				return -EINVAL;
			}

			if (mddev->delta_disks < 0 ||
			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
				mddev->reshape_backwards = 1;
			else
				mddev->reshape_backwards = 0;

			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
		}

	} else {
		/*
		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
		 */
		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);

		if (rs_takeover_requested(rs)) {
			if (rt_cur && rt_new)
				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
				      rt_cur->name, rt_new->name);
			else
				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
			return -EINVAL;
		} else if (rs_reshape_requested(rs)) {
			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
			if (mddev->layout != mddev->new_layout) {
				if (rt_cur && rt_new)
					DMERR("	 current layout %s vs new layout %s",
					      rt_cur->name, rt_new->name);
				else
					DMERR("	 current layout 0x%X vs new layout 0x%X",
					      le32_to_cpu(sb->layout), mddev->new_layout);
			}
			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
				      mddev->chunk_sectors, mddev->new_chunk_sectors);
			if (rs->delta_disks)
				DMERR("	 current %u disks vs new %u disks",
				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
			if (rs_is_raid10(rs)) {
				DMERR("	 Old layout: %s w/ %u copies",
				      raid10_md_layout_to_format(mddev->layout),
				      raid10_md_layout_to_copies(mddev->layout));
				DMERR("	 New layout: %s w/ %u copies",
				      raid10_md_layout_to_format(mddev->new_layout),
				      raid10_md_layout_to_copies(mddev->new_layout));
			}
			return -EINVAL;
		}

		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
	}

	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);

	/*
	 * During load, we set FirstUse if a new superblock was written.
	 * There are two reasons we might not have a superblock:
	 * 1) The raid set is brand new - in which case, all of the
	 *    devices must have their In_sync bit set.	Also,
	 *    recovery_cp must be 0, unless forced.
	 * 2) This is a new device being added to an old raid set
	 *    and the new device needs to be rebuilt - in which
	 *    case the In_sync bit will /not/ be set and
	 *    recovery_cp must be MaxSector.
	 * 3) This is/are a new device(s) being added to an old
	 *    raid set during takeover to a higher raid level
	 *    to provide capacity for redundancy or during reshape
	 *    to add capacity to grow the raid set.
	 */
	d = 0;
	rdev_for_each(r, mddev) {
		if (test_bit(Journal, &rdev->flags))
			continue;

		if (test_bit(FirstUse, &r->flags))
			new_devs++;

		if (!test_bit(In_sync, &r->flags)) {
			DMINFO("Device %d specified for rebuild; clearing superblock",
				r->raid_disk);
			rebuilds++;

			if (test_bit(FirstUse, &r->flags))
				rebuild_and_new++;
		}

		d++;
	}

	if (new_devs == rs->raid_disks || !rebuilds) {
		/* Replace a broken device */
		if (new_devs == rs->raid_disks) {
			DMINFO("Superblocks created for new raid set");
			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
		} else if (new_devs != rebuilds &&
			   new_devs != rs->delta_disks) {
			DMERR("New device injected into existing raid set without "
			      "'delta_disks' or 'rebuild' parameter specified");
			return -EINVAL;
		}
	} else if (new_devs && new_devs != rebuilds) {
		DMERR("%u 'rebuild' devices cannot be injected into"
		      " a raid set with %u other first-time devices",
		      rebuilds, new_devs);
		return -EINVAL;
	} else if (rebuilds) {
		if (rebuild_and_new && rebuilds != rebuild_and_new) {
			DMERR("new device%s provided without 'rebuild'",
			      new_devs > 1 ? "s" : "");
			return -EINVAL;
		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
			      (unsigned long long) mddev->recovery_cp);
			return -EINVAL;
		} else if (rs_is_reshaping(rs)) {
			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
			      (unsigned long long) mddev->reshape_position);
			return -EINVAL;
		}
	}

	/*
	 * Now we set the Faulty bit for those devices that are
	 * recorded in the superblock as failed.
	 */
	sb_retrieve_failed_devices(sb, failed_devices);
	rdev_for_each(r, mddev) {
		if (test_bit(Journal, &rdev->flags) ||
		    !r->sb_page)
			continue;
		sb2 = page_address(r->sb_page);
		sb2->failed_devices = 0;
		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));

		/*
		 * Check for any device re-ordering.
		 */
		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
			role = le32_to_cpu(sb2->array_position);
			if (role < 0)
				continue;

			if (role != r->raid_disk) {
				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
					    rs->raid_disks % rs->raid10_copies) {
						rs->ti->error =
							"Cannot change raid10 near set to odd # of devices!";
						return -EINVAL;
					}

					sb2->array_position = cpu_to_le32(r->raid_disk);

				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
					   !rt_is_raid1(rs->raid_type)) {
					rs->ti->error = "Cannot change device positions in raid set";
					return -EINVAL;
				}

				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
			}

			/*
			 * Partial recovery is performed on
			 * returning failed devices.
			 */
			if (test_bit(role, (void *) failed_devices))
				set_bit(Faulty, &r->flags);
		}
	}

	return 0;
}

static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
{
	struct mddev *mddev = &rs->md;
	struct dm_raid_superblock *sb;

	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
		return 0;

	sb = page_address(rdev->sb_page);

	/*
	 * If mddev->events is not set, we know we have not yet initialized
	 * the array.
	 */
	if (!mddev->events && super_init_validation(rs, rdev))
		return -EINVAL;

	if (le32_to_cpu(sb->compat_features) &&
	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
		return -EINVAL;
	}

	if (sb->incompat_features) {
		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
		return -EINVAL;
	}

	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;

	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
		/*
		 * Retrieve rdev size stored in superblock to be prepared for shrink.
		 * Check extended superblock members are present otherwise the size
		 * will not be set!
		 */
		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
			rdev->sectors = le64_to_cpu(sb->sectors);

		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
		if (rdev->recovery_offset == MaxSector)
			set_bit(In_sync, &rdev->flags);
		/*
		 * If no reshape in progress -> we're recovering single
		 * disk(s) and have to set the device(s) to out-of-sync
		 */
		else if (!rs_is_reshaping(rs))
			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
	}

	/*
	 * If a device comes back, set it as not In_sync and no longer faulty.
	 */
	if (test_and_clear_bit(Faulty, &rdev->flags)) {
		rdev->recovery_offset = 0;
		clear_bit(In_sync, &rdev->flags);
		rdev->saved_raid_disk = rdev->raid_disk;
	}

	/* Reshape support -> restore repective data offsets */
	rdev->data_offset = le64_to_cpu(sb->data_offset);
	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);

	return 0;
}

/*
 * Analyse superblocks and select the freshest.
 */
static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
{
	int r;
	struct md_rdev *rdev, *freshest;
	struct mddev *mddev = &rs->md;

	freshest = NULL;
	rdev_for_each(rdev, mddev) {
		if (test_bit(Journal, &rdev->flags))
			continue;

		if (!rdev->meta_bdev)
			continue;

		/* Set superblock offset/size for metadata device. */
		rdev->sb_start = 0;
		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
			DMERR("superblock size of a logical block is no longer valid");
			return -EINVAL;
		}

		/*
		 * Skipping super_load due to CTR_FLAG_SYNC will cause
		 * the array to undergo initialization again as
		 * though it were new.	This is the intended effect
		 * of the "sync" directive.
		 *
		 * With reshaping capability added, we must ensure that
		 * that the "sync" directive is disallowed during the reshape.
		 */
		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
			continue;

		r = super_load(rdev, freshest);

		switch (r) {
		case 1:
			freshest = rdev;
			break;
		case 0:
			break;
		default:
			/* This is a failure to read the superblock from the metadata device. */
			/*
			 * We have to keep any raid0 data/metadata device pairs or
			 * the MD raid0 personality will fail to start the array.
			 */
			if (rs_is_raid0(rs))
				continue;

			/*
			 * We keep the dm_devs to be able to emit the device tuple
			 * properly on the table line in raid_status() (rather than
			 * mistakenly acting as if '- -' got passed into the constructor).
			 *
			 * The rdev has to stay on the same_set list to allow for
			 * the attempt to restore faulty devices on second resume.
			 */
			rdev->raid_disk = rdev->saved_raid_disk = -1;
			break;
		}
	}

	if (!freshest)
		return 0;

	/*
	 * Validation of the freshest device provides the source of
	 * validation for the remaining devices.
	 */
	rs->ti->error = "Unable to assemble array: Invalid superblocks";
	if (super_validate(rs, freshest))
		return -EINVAL;

	if (validate_raid_redundancy(rs)) {
		rs->ti->error = "Insufficient redundancy to activate array";
		return -EINVAL;
	}

	rdev_for_each(rdev, mddev)
		if (!test_bit(Journal, &rdev->flags) &&
		    rdev != freshest &&
		    super_validate(rs, rdev))
			return -EINVAL;
	return 0;
}

/*
 * Adjust data_offset and new_data_offset on all disk members of @rs
 * for out of place reshaping if requested by contructor
 *
 * We need free space at the beginning of each raid disk for forward
 * and at the end for backward reshapes which userspace has to provide
 * via remapping/reordering of space.
 */
static int rs_adjust_data_offsets(struct raid_set *rs)
{
	sector_t data_offset = 0, new_data_offset = 0;
	struct md_rdev *rdev;

	/* Constructor did not request data offset change */
	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
		if (!rs_is_reshapable(rs))
			goto out;

		return 0;
	}

	/* HM FIXME: get In_Sync raid_dev? */
	rdev = &rs->dev[0].rdev;

	if (rs->delta_disks < 0) {
		/*
		 * Removing disks (reshaping backwards):
		 *
		 * - before reshape: data is at offset 0 and free space
		 *		     is at end of each component LV
		 *
		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
		 */
		data_offset = 0;
		new_data_offset = rs->data_offset;

	} else if (rs->delta_disks > 0) {
		/*
		 * Adding disks (reshaping forwards):
		 *
		 * - before reshape: data is at offset rs->data_offset != 0 and
		 *		     free space is at begin of each component LV
		 *
		 * - after reshape: data is at offset 0 on each component LV
		 */
		data_offset = rs->data_offset;
		new_data_offset = 0;

	} else {
		/*
		 * User space passes in 0 for data offset after having removed reshape space
		 *
		 * - or - (data offset != 0)
		 *
		 * Changing RAID layout or chunk size -> toggle offsets
		 *
		 * - before reshape: data is at offset rs->data_offset 0 and
		 *		     free space is at end of each component LV
		 *		     -or-
		 *                   data is at offset rs->data_offset != 0 and
		 *		     free space is at begin of each component LV
		 *
		 * - after reshape: data is at offset 0 if it was at offset != 0
		 *                  or at offset != 0 if it was at offset 0
		 *                  on each component LV
		 *
		 */
		data_offset = rs->data_offset ? rdev->data_offset : 0;
		new_data_offset = data_offset ? 0 : rs->data_offset;
		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
	}

	/*
	 * Make sure we got a minimum amount of free sectors per device
	 */
	if (rs->data_offset &&
	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
		rs->ti->error = data_offset ? "No space for forward reshape" :
					      "No space for backward reshape";
		return -ENOSPC;
	}
out:
	/*
	 * Raise recovery_cp in case data_offset != 0 to
	 * avoid false recovery positives in the constructor.
	 */
	if (rs->md.recovery_cp < rs->md.dev_sectors)
		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;

	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
	rdev_for_each(rdev, &rs->md) {
		if (!test_bit(Journal, &rdev->flags)) {
			rdev->data_offset = data_offset;
			rdev->new_data_offset = new_data_offset;
		}
	}

	return 0;
}

/* Userpace reordered disks -> adjust raid_disk indexes in @rs */
static void __reorder_raid_disk_indexes(struct raid_set *rs)
{
	int i = 0;
	struct md_rdev *rdev;

	rdev_for_each(rdev, &rs->md) {
		if (!test_bit(Journal, &rdev->flags)) {
			rdev->raid_disk = i++;
			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
		}
	}
}

/*
 * Setup @rs for takeover by a different raid level
 */
static int rs_setup_takeover(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;
	struct md_rdev *rdev;
	unsigned int d = mddev->raid_disks = rs->raid_disks;
	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;

	if (rt_is_raid10(rs->raid_type)) {
		if (rs_is_raid0(rs)) {
			/* Userpace reordered disks -> adjust raid_disk indexes */
			__reorder_raid_disk_indexes(rs);

			/* raid0 -> raid10_far layout */
			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
								   rs->raid10_copies);
		} else if (rs_is_raid1(rs))
			/* raid1 -> raid10_near layout */
			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
								   rs->raid_disks);
		else
			return -EINVAL;

	}

	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
	mddev->recovery_cp = MaxSector;

	while (d--) {
		rdev = &rs->dev[d].rdev;

		if (test_bit(d, (void *) rs->rebuild_disks)) {
			clear_bit(In_sync, &rdev->flags);
			clear_bit(Faulty, &rdev->flags);
			mddev->recovery_cp = rdev->recovery_offset = 0;
			/* Bitmap has to be created when we do an "up" takeover */
			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
		}

		rdev->new_data_offset = new_data_offset;
	}

	return 0;
}

/* Prepare @rs for reshape */
static int rs_prepare_reshape(struct raid_set *rs)
{
	bool reshape;
	struct mddev *mddev = &rs->md;

	if (rs_is_raid10(rs)) {
		if (rs->raid_disks != mddev->raid_disks &&
		    __is_raid10_near(mddev->layout) &&
		    rs->raid10_copies &&
		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
			/*
			 * raid disk have to be multiple of data copies to allow this conversion,
			 *
			 * This is actually not a reshape it is a
			 * rebuild of any additional mirrors per group
			 */
			if (rs->raid_disks % rs->raid10_copies) {
				rs->ti->error = "Can't reshape raid10 mirror groups";
				return -EINVAL;
			}

			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
			__reorder_raid_disk_indexes(rs);
			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
								   rs->raid10_copies);
			mddev->new_layout = mddev->layout;
			reshape = false;
		} else
			reshape = true;

	} else if (rs_is_raid456(rs))
		reshape = true;

	else if (rs_is_raid1(rs)) {
		if (rs->delta_disks) {
			/* Process raid1 via delta_disks */
			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
			reshape = true;
		} else {
			/* Process raid1 without delta_disks */
			mddev->raid_disks = rs->raid_disks;
			reshape = false;
		}
	} else {
		rs->ti->error = "Called with bogus raid type";
		return -EINVAL;
	}

	if (reshape) {
		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
	} else if (mddev->raid_disks < rs->raid_disks)
		/* Create new superblocks and bitmaps, if any new disks */
		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);

	return 0;
}

/* Get reshape sectors from data_offsets or raid set */
static sector_t _get_reshape_sectors(struct raid_set *rs)
{
	struct md_rdev *rdev;
	sector_t reshape_sectors = 0;

	rdev_for_each(rdev, &rs->md)
		if (!test_bit(Journal, &rdev->flags)) {
			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
					rdev->data_offset - rdev->new_data_offset :
					rdev->new_data_offset - rdev->data_offset;
			break;
		}

	return max(reshape_sectors, (sector_t) rs->data_offset);
}

/*
 *
 * - change raid layout
 * - change chunk size
 * - add disks
 * - remove disks
 */
static int rs_setup_reshape(struct raid_set *rs)
{
	int r = 0;
	unsigned int cur_raid_devs, d;
	sector_t reshape_sectors = _get_reshape_sectors(rs);
	struct mddev *mddev = &rs->md;
	struct md_rdev *rdev;

	mddev->delta_disks = rs->delta_disks;
	cur_raid_devs = mddev->raid_disks;

	/* Ignore impossible layout change whilst adding/removing disks */
	if (mddev->delta_disks &&
	    mddev->layout != mddev->new_layout) {
		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
		mddev->new_layout = mddev->layout;
	}

	/*
	 * Adjust array size:
	 *
	 * - in case of adding disk(s), array size has
	 *   to grow after the disk adding reshape,
	 *   which'll hapen in the event handler;
	 *   reshape will happen forward, so space has to
	 *   be available at the beginning of each disk
	 *
	 * - in case of removing disk(s), array size
	 *   has to shrink before starting the reshape,
	 *   which'll happen here;
	 *   reshape will happen backward, so space has to
	 *   be available at the end of each disk
	 *
	 * - data_offset and new_data_offset are
	 *   adjusted for aforementioned out of place
	 *   reshaping based on userspace passing in
	 *   the "data_offset <sectors>" key/value
	 *   pair via the constructor
	 */

	/* Add disk(s) */
	if (rs->delta_disks > 0) {
		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
			rdev = &rs->dev[d].rdev;
			clear_bit(In_sync, &rdev->flags);

			/*
			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
			 * by md, which'll store that erroneously in the superblock on reshape
			 */
			rdev->saved_raid_disk = -1;
			rdev->raid_disk = d;

			rdev->sectors = mddev->dev_sectors;
			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
		}

		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */

	/* Remove disk(s) */
	} else if (rs->delta_disks < 0) {
		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */

	/* Change layout and/or chunk size */
	} else {
		/*
		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
		 *
		 * keeping number of disks and do layout change ->
		 *
		 * toggle reshape_backward depending on data_offset:
		 *
		 * - free space upfront -> reshape forward
		 *
		 * - free space at the end -> reshape backward
		 *
		 *
		 * This utilizes free reshape space avoiding the need
		 * for userspace to move (parts of) LV segments in
		 * case of layout/chunksize change  (for disk
		 * adding/removing reshape space has to be at
		 * the proper address (see above with delta_disks):
		 *
		 * add disk(s)   -> begin
		 * remove disk(s)-> end
		 */
		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
	}

	/*
	 * Adjust device size for forward reshape
	 * because md_finish_reshape() reduces it.
	 */
	if (!mddev->reshape_backwards)
		rdev_for_each(rdev, &rs->md)
			if (!test_bit(Journal, &rdev->flags))
				rdev->sectors += reshape_sectors;

	return r;
}

/*
 * Enable/disable discard support on RAID set depending on
 * RAID level and discard properties of underlying RAID members.
 */
static void configure_discard_support(struct raid_set *rs)
{
	int i;
	bool raid456;
	struct dm_target *ti = rs->ti;

	/*
	 * XXX: RAID level 4,5,6 require zeroing for safety.
	 */
	raid456 = rs_is_raid456(rs);

	for (i = 0; i < rs->raid_disks; i++) {
		struct request_queue *q;

		if (!rs->dev[i].rdev.bdev)
			continue;

		q = bdev_get_queue(rs->dev[i].rdev.bdev);
		if (!q || !blk_queue_discard(q))
			return;

		if (raid456) {
			if (!devices_handle_discard_safely) {
				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
				return;
			}
		}
	}

	ti->num_discard_bios = 1;
}

/*
 * Construct a RAID0/1/10/4/5/6 mapping:
 * Args:
 *	<raid_type> <#raid_params> <raid_params>{0,}	\
 *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
 *
 * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
 * details on possible <raid_params>.
 *
 * Userspace is free to initialize the metadata devices, hence the superblocks to
 * enforce recreation based on the passed in table parameters.
 *
 */
static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	int r;
	bool resize = false;
	struct raid_type *rt;
	unsigned int num_raid_params, num_raid_devs;
	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
	struct raid_set *rs = NULL;
	const char *arg;
	struct rs_layout rs_layout;
	struct dm_arg_set as = { argc, argv }, as_nrd;
	struct dm_arg _args[] = {
		{ 0, as.argc, "Cannot understand number of raid parameters" },
		{ 1, 254, "Cannot understand number of raid devices parameters" }
	};

	arg = dm_shift_arg(&as);
	if (!arg) {
		ti->error = "No arguments";
		return -EINVAL;
	}

	rt = get_raid_type(arg);
	if (!rt) {
		ti->error = "Unrecognised raid_type";
		return -EINVAL;
	}

	/* Must have <#raid_params> */
	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
		return -EINVAL;

	/* number of raid device tupples <meta_dev data_dev> */
	as_nrd = as;
	dm_consume_args(&as_nrd, num_raid_params);
	_args[1].max = (as_nrd.argc - 1) / 2;
	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
		return -EINVAL;

	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
		ti->error = "Invalid number of supplied raid devices";
		return -EINVAL;
	}

	rs = raid_set_alloc(ti, rt, num_raid_devs);
	if (IS_ERR(rs))
		return PTR_ERR(rs);

	r = parse_raid_params(rs, &as, num_raid_params);
	if (r)
		goto bad;

	r = parse_dev_params(rs, &as);
	if (r)
		goto bad;

	rs->md.sync_super = super_sync;

	/*
	 * Calculate ctr requested array and device sizes to allow
	 * for superblock analysis needing device sizes defined.
	 *
	 * Any existing superblock will overwrite the array and device sizes
	 */
	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
	if (r)
		goto bad;

	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
	rs->array_sectors = rs->md.array_sectors;
	rs->dev_sectors = rs->md.dev_sectors;

	/*
	 * Backup any new raid set level, layout, ...
	 * requested to be able to compare to superblock
	 * members for conversion decisions.
	 */
	rs_config_backup(rs, &rs_layout);

	r = analyse_superblocks(ti, rs);
	if (r)
		goto bad;

	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
	sb_array_sectors = rs->md.array_sectors;
	rdev_sectors = __rdev_sectors(rs);
	if (!rdev_sectors) {
		ti->error = "Invalid rdev size";
		r = -EINVAL;
		goto bad;
	}


	reshape_sectors = _get_reshape_sectors(rs);
	if (rs->dev_sectors != rdev_sectors) {
		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
	}

	INIT_WORK(&rs->md.event_work, do_table_event);
	ti->private = rs;
	ti->num_flush_bios = 1;

	/* Restore any requested new layout for conversion decision */
	rs_config_restore(rs, &rs_layout);

	/*
	 * Now that we have any superblock metadata available,
	 * check for new, recovering, reshaping, to be taken over,
	 * to be reshaped or an existing, unchanged raid set to
	 * run in sequence.
	 */
	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
		if (rs_is_raid6(rs) &&
		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
			ti->error = "'nosync' not allowed for new raid6 set";
			r = -EINVAL;
			goto bad;
		}
		rs_setup_recovery(rs, 0);
		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
		rs_set_new(rs);
	} else if (rs_is_recovering(rs)) {
		/* A recovering raid set may be resized */
		goto size_check;
	} else if (rs_is_reshaping(rs)) {
		/* Have to reject size change request during reshape */
		if (resize) {
			ti->error = "Can't resize a reshaping raid set";
			r = -EPERM;
			goto bad;
		}
		/* skip setup rs */
	} else if (rs_takeover_requested(rs)) {
		if (rs_is_reshaping(rs)) {
			ti->error = "Can't takeover a reshaping raid set";
			r = -EPERM;
			goto bad;
		}

		/* We can't takeover a journaled raid4/5/6 */
		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
			ti->error = "Can't takeover a journaled raid4/5/6 set";
			r = -EPERM;
			goto bad;
		}

		/*
		 * If a takeover is needed, userspace sets any additional
		 * devices to rebuild and we can check for a valid request here.
		 *
		 * If acceptible, set the level to the new requested
		 * one, prohibit requesting recovery, allow the raid
		 * set to run and store superblocks during resume.
		 */
		r = rs_check_takeover(rs);
		if (r)
			goto bad;

		r = rs_setup_takeover(rs);
		if (r)
			goto bad;

		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
		/* Takeover ain't recovery, so disable recovery */
		rs_setup_recovery(rs, MaxSector);
		rs_set_new(rs);
	} else if (rs_reshape_requested(rs)) {
		/* Only request grow on raid set size extensions, not on reshapes. */
		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);

		/*
		 * No need to check for 'ongoing' takeover here, because takeover
		 * is an instant operation as oposed to an ongoing reshape.
		 */

		/* We can't reshape a journaled raid4/5/6 */
		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
			ti->error = "Can't reshape a journaled raid4/5/6 set";
			r = -EPERM;
			goto bad;
		}

		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
		if (reshape_sectors || rs_is_raid1(rs)) {
			/*
			  * We can only prepare for a reshape here, because the
			  * raid set needs to run to provide the repective reshape
			  * check functions via its MD personality instance.
			  *
			  * So do the reshape check after md_run() succeeded.
			  */
			r = rs_prepare_reshape(rs);
			if (r)
				goto bad;

			/* Reshaping ain't recovery, so disable recovery */
			rs_setup_recovery(rs, MaxSector);
		}
		rs_set_cur(rs);
	} else {
size_check:
		/* May not set recovery when a device rebuild is requested */
		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
			rs_setup_recovery(rs, MaxSector);
		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
			/*
			 * Set raid set to current size, i.e. size as of
			 * superblocks to grow to larger size in preresume.
			 */
			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
			if (r)
				goto bad;

			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
		} else {
			/* This is no size change or it is shrinking, update size and record in superblocks */
			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
			if (r)
				goto bad;

			if (sb_array_sectors > rs->array_sectors)
				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
		}
		rs_set_cur(rs);
	}

	/* If constructor requested it, change data and new_data offsets */
	r = rs_adjust_data_offsets(rs);
	if (r)
		goto bad;

	/* Start raid set read-only and assumed clean to change in raid_resume() */
	rs->md.ro = 1;
	rs->md.in_sync = 1;

	/* Keep array frozen */
	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);

	/* Has to be held on running the array */
	mddev_lock_nointr(&rs->md);
	r = md_run(&rs->md);
	rs->md.in_sync = 0; /* Assume already marked dirty */
	if (r) {
		ti->error = "Failed to run raid array";
		mddev_unlock(&rs->md);
		goto bad;
	}

	r = md_start(&rs->md);

	if (r) {
		ti->error = "Failed to start raid array";
		mddev_unlock(&rs->md);
		goto bad_md_start;
	}

	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
		if (r) {
			ti->error = "Failed to set raid4/5/6 journal mode";
			mddev_unlock(&rs->md);
			goto bad_journal_mode_set;
		}
	}

	mddev_suspend(&rs->md);
	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);

	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
	if (rs_is_raid456(rs)) {
		r = rs_set_raid456_stripe_cache(rs);
		if (r)
			goto bad_stripe_cache;
	}

	/* Now do an early reshape check */
	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
		r = rs_check_reshape(rs);
		if (r)
			goto bad_check_reshape;

		/* Restore new, ctr requested layout to perform check */
		rs_config_restore(rs, &rs_layout);

		if (rs->md.pers->start_reshape) {
			r = rs->md.pers->check_reshape(&rs->md);
			if (r) {
				ti->error = "Reshape check failed";
				goto bad_check_reshape;
			}
		}
	}

	/* Disable/enable discard support on raid set. */
	configure_discard_support(rs);

	mddev_unlock(&rs->md);
	return 0;

bad_md_start:
bad_journal_mode_set:
bad_stripe_cache:
bad_check_reshape:
	md_stop(&rs->md);
bad:
	raid_set_free(rs);

	return r;
}

static void raid_dtr(struct dm_target *ti)
{
	struct raid_set *rs = ti->private;

	md_stop(&rs->md);
	raid_set_free(rs);
}

static int raid_map(struct dm_target *ti, struct bio *bio)
{
	struct raid_set *rs = ti->private;
	struct mddev *mddev = &rs->md;

	/*
	 * If we're reshaping to add disk(s)), ti->len and
	 * mddev->array_sectors will differ during the process
	 * (ti->len > mddev->array_sectors), so we have to requeue
	 * bios with addresses > mddev->array_sectors here or
	 * there will occur accesses past EOD of the component
	 * data images thus erroring the raid set.
	 */
	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
		return DM_MAPIO_REQUEUE;

	md_handle_request(mddev, bio);

	return DM_MAPIO_SUBMITTED;
}

/* Return sync state string for @state */
enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
static const char *sync_str(enum sync_state state)
{
	/* Has to be in above sync_state order! */
	static const char *sync_strs[] = {
		"frozen",
		"reshape",
		"resync",
		"check",
		"repair",
		"recover",
		"idle"
	};

	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
};

/* Return enum sync_state for @mddev derived from @recovery flags */
static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
{
	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
		return st_frozen;

	/* The MD sync thread can be done with io or be interrupted but still be running */
	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
			return st_reshape;

		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
				return st_resync;
			if (test_bit(MD_RECOVERY_CHECK, &recovery))
				return st_check;
			return st_repair;
		}

		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
			return st_recover;

		if (mddev->reshape_position != MaxSector)
			return st_reshape;
	}

	return st_idle;
}

/*
 * Return status string for @rdev
 *
 * Status characters:
 *
 *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
 *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
 *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
 *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
 */
static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
{
	if (!rdev->bdev)
		return "-";
	else if (test_bit(Faulty, &rdev->flags))
		return "D";
	else if (test_bit(Journal, &rdev->flags))
		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
		  !test_bit(In_sync, &rdev->flags)))
		return "a";
	else
		return "A";
}

/* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
				enum sync_state state, sector_t resync_max_sectors)
{
	sector_t r;
	struct mddev *mddev = &rs->md;

	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);

	if (rs_is_raid0(rs)) {
		r = resync_max_sectors;
		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);

	} else {
		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
			r = mddev->recovery_cp;
		else
			r = mddev->curr_resync_completed;

		if (state == st_idle && r >= resync_max_sectors) {
			/*
			 * Sync complete.
			 */
			/* In case we have finished recovering, the array is in sync. */
			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);

		} else if (state == st_recover)
			/*
			 * In case we are recovering, the array is not in sync
			 * and health chars should show the recovering legs.
			 *
			 * Already retrieved recovery offset from curr_resync_completed above.
			 */
			;

		else if (state == st_resync || state == st_reshape)
			/*
			 * If "resync/reshape" is occurring, the raid set
			 * is or may be out of sync hence the health
			 * characters shall be 'a'.
			 */
			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);

		else if (state == st_check || state == st_repair)
			/*
			 * If "check" or "repair" is occurring, the raid set has
			 * undergone an initial sync and the health characters
			 * should not be 'a' anymore.
			 */
			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);

		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
			/*
			 * We are idle and recovery is needed, prevent 'A' chars race
			 * caused by components still set to in-sync by constructor.
			 */
			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);

		else {
			/*
			 * We are idle and the raid set may be doing an initial
			 * sync, or it may be rebuilding individual components.
			 * If all the devices are In_sync, then it is the raid set
			 * that is being initialized.
			 */
			struct md_rdev *rdev;

			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
			rdev_for_each(rdev, mddev)
				if (!test_bit(Journal, &rdev->flags) &&
				    !test_bit(In_sync, &rdev->flags)) {
					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
					break;
				}
		}
	}

	return min(r, resync_max_sectors);
}

/* Helper to return @dev name or "-" if !@dev */
static const char *__get_dev_name(struct dm_dev *dev)
{
	return dev ? dev->name : "-";
}

static void raid_status(struct dm_target *ti, status_type_t type,
			unsigned int status_flags, char *result, unsigned int maxlen)
{
	struct raid_set *rs = ti->private;
	struct mddev *mddev = &rs->md;
	struct r5conf *conf = mddev->private;
	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
	unsigned long recovery;
	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
	unsigned int sz = 0;
	unsigned int rebuild_writemostly_count = 0;
	sector_t progress, resync_max_sectors, resync_mismatches;
	enum sync_state state;
	struct raid_type *rt;

	switch (type) {
	case STATUSTYPE_INFO:
		/* *Should* always succeed */
		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
		if (!rt)
			return;

		DMEMIT("%s %d ", rt->name, mddev->raid_disks);

		/* Access most recent mddev properties for status output */
		smp_rmb();
		/* Get sensible max sectors even if raid set not yet started */
		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
				      mddev->resync_max_sectors : mddev->dev_sectors;
		recovery = rs->md.recovery;
		state = decipher_sync_action(mddev, recovery);
		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
				    atomic64_read(&mddev->resync_mismatches) : 0;

		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
		for (i = 0; i < rs->raid_disks; i++)
			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));

		/*
		 * In-sync/Reshape ratio:
		 *  The in-sync ratio shows the progress of:
		 *   - Initializing the raid set
		 *   - Rebuilding a subset of devices of the raid set
		 *  The user can distinguish between the two by referring
		 *  to the status characters.
		 *
		 *  The reshape ratio shows the progress of
		 *  changing the raid layout or the number of
		 *  disks of a raid set
		 */
		DMEMIT(" %llu/%llu", (unsigned long long) progress,
				     (unsigned long long) resync_max_sectors);

		/*
		 * v1.5.0+:
		 *
		 * Sync action:
		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
		 *   information on each of these states.
		 */
		DMEMIT(" %s", sync_str(state));

		/*
		 * v1.5.0+:
		 *
		 * resync_mismatches/mismatch_cnt
		 *   This field shows the number of discrepancies found when
		 *   performing a "check" of the raid set.
		 */
		DMEMIT(" %llu", (unsigned long long) resync_mismatches);

		/*
		 * v1.9.0+:
		 *
		 * data_offset (needed for out of space reshaping)
		 *   This field shows the data offset into the data
		 *   image LV where the first stripes data starts.
		 *
		 * We keep data_offset equal on all raid disks of the set,
		 * so retrieving it from the first raid disk is sufficient.
		 */
		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);

		/*
		 * v1.10.0+:
		 */
		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
		break;

	case STATUSTYPE_TABLE:
		/* Report the table line string you would use to construct this raid set */

		/*
		 * Count any rebuild or writemostly argument pairs and subtract the
		 * hweight count being added below of any rebuild and writemostly ctr flags.
		 */
		for (i = 0; i < rs->raid_disks; i++) {
			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
		}
		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
		raid_param_cnt += rebuild_writemostly_count +
				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
		/* Emit table line */
		/* This has to be in the documented order for userspace! */
		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
			for (i = 0; i < rs->raid_disks; i++)
				if (test_bit(i, (void *) rs->rebuild_disks))
					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
					  mddev->bitmap_info.daemon_sleep);
		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
					 mddev->sync_speed_min);
		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
					 mddev->sync_speed_max);
		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
			for (i = 0; i < rs->raid_disks; i++)
				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
					       rs->dev[i].rdev.raid_disk);
		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
					  mddev->bitmap_info.max_write_behind);
		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
					 max_nr_stripes);
		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
					 raid10_md_layout_to_copies(mddev->layout));
		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
					 raid10_md_layout_to_format(mddev->layout));
		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
					 max(rs->delta_disks, mddev->delta_disks));
		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
					   (unsigned long long) rs->data_offset);
		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
					__get_dev_name(rs->journal_dev.dev));
		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
		DMEMIT(" %d", rs->raid_disks);
		for (i = 0; i < rs->raid_disks; i++)
			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
					 __get_dev_name(rs->dev[i].data_dev));
	}
}

static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
			char *result, unsigned maxlen)
{
	struct raid_set *rs = ti->private;
	struct mddev *mddev = &rs->md;

	if (!mddev->pers || !mddev->pers->sync_request)
		return -EINVAL;

	if (!strcasecmp(argv[0], "frozen"))
		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
	else
		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);

	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
		if (mddev->sync_thread) {
			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
			md_reap_sync_thread(mddev);
		}
	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
		return -EBUSY;
	else if (!strcasecmp(argv[0], "resync"))
		; /* MD_RECOVERY_NEEDED set below */
	else if (!strcasecmp(argv[0], "recover"))
		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
	else {
		if (!strcasecmp(argv[0], "check")) {
			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
		} else if (!strcasecmp(argv[0], "repair")) {
			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
		} else
			return -EINVAL;
	}
	if (mddev->ro == 2) {
		/* A write to sync_action is enough to justify
		 * canceling read-auto mode
		 */
		mddev->ro = 0;
		if (!mddev->suspended && mddev->sync_thread)
			md_wakeup_thread(mddev->sync_thread);
	}
	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	if (!mddev->suspended && mddev->thread)
		md_wakeup_thread(mddev->thread);

	return 0;
}

static int raid_iterate_devices(struct dm_target *ti,
				iterate_devices_callout_fn fn, void *data)
{
	struct raid_set *rs = ti->private;
	unsigned int i;
	int r = 0;

	for (i = 0; !r && i < rs->md.raid_disks; i++)
		if (rs->dev[i].data_dev)
			r = fn(ti,
				 rs->dev[i].data_dev,
				 0, /* No offset on data devs */
				 rs->md.dev_sectors,
				 data);

	return r;
}

static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
	struct raid_set *rs = ti->private;
	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);

	blk_limits_io_min(limits, chunk_size_bytes);
	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));

	/*
	 * RAID0 and RAID10 personalities require bio splitting,
	 * RAID1/4/5/6 don't and process large discard bios properly.
	 */
	if (rs_is_raid0(rs) || rs_is_raid10(rs)) {
		limits->discard_granularity = chunk_size_bytes;
		limits->max_discard_sectors = rs->md.chunk_sectors;
	}
}

static void raid_postsuspend(struct dm_target *ti)
{
	struct raid_set *rs = ti->private;

	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
		/* Writes have to be stopped before suspending to avoid deadlocks. */
		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
			md_stop_writes(&rs->md);

		mddev_lock_nointr(&rs->md);
		mddev_suspend(&rs->md);
		mddev_unlock(&rs->md);
	}
}

static void attempt_restore_of_faulty_devices(struct raid_set *rs)
{
	int i;
	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
	unsigned long flags;
	bool cleared = false;
	struct dm_raid_superblock *sb;
	struct mddev *mddev = &rs->md;
	struct md_rdev *r;

	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
		return;

	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));

	for (i = 0; i < mddev->raid_disks; i++) {
		r = &rs->dev[i].rdev;
		/* HM FIXME: enhance journal device recovery processing */
		if (test_bit(Journal, &r->flags))
			continue;

		if (test_bit(Faulty, &r->flags) &&
		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
			DMINFO("Faulty %s device #%d has readable super block."
			       "  Attempting to revive it.",
			       rs->raid_type->name, i);

			/*
			 * Faulty bit may be set, but sometimes the array can
			 * be suspended before the personalities can respond
			 * by removing the device from the array (i.e. calling
			 * 'hot_remove_disk').	If they haven't yet removed
			 * the failed device, its 'raid_disk' number will be
			 * '>= 0' - meaning we must call this function
			 * ourselves.
			 */
			flags = r->flags;
			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
			if (r->raid_disk >= 0) {
				if (mddev->pers->hot_remove_disk(mddev, r)) {
					/* Failed to revive this device, try next */
					r->flags = flags;
					continue;
				}
			} else
				r->raid_disk = r->saved_raid_disk = i;

			clear_bit(Faulty, &r->flags);
			clear_bit(WriteErrorSeen, &r->flags);

			if (mddev->pers->hot_add_disk(mddev, r)) {
				/* Failed to revive this device, try next */
				r->raid_disk = r->saved_raid_disk = -1;
				r->flags = flags;
			} else {
				clear_bit(In_sync, &r->flags);
				r->recovery_offset = 0;
				set_bit(i, (void *) cleared_failed_devices);
				cleared = true;
			}
		}
	}

	/* If any failed devices could be cleared, update all sbs failed_devices bits */
	if (cleared) {
		uint64_t failed_devices[DISKS_ARRAY_ELEMS];

		rdev_for_each(r, &rs->md) {
			if (test_bit(Journal, &r->flags))
				continue;

			sb = page_address(r->sb_page);
			sb_retrieve_failed_devices(sb, failed_devices);

			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
				failed_devices[i] &= ~cleared_failed_devices[i];

			sb_update_failed_devices(sb, failed_devices);
		}
	}
}

static int __load_dirty_region_bitmap(struct raid_set *rs)
{
	int r = 0;

	/* Try loading the bitmap unless "raid0", which does not have one */
	if (!rs_is_raid0(rs) &&
	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
		r = md_bitmap_load(&rs->md);
		if (r)
			DMERR("Failed to load bitmap");
	}

	return r;
}

/* Enforce updating all superblocks */
static void rs_update_sbs(struct raid_set *rs)
{
	struct mddev *mddev = &rs->md;
	int ro = mddev->ro;

	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
	mddev->ro = 0;
	md_update_sb(mddev, 1);
	mddev->ro = ro;
}

/*
 * Reshape changes raid algorithm of @rs to new one within personality
 * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
 * disks from a raid set thus growing/shrinking it or resizes the set
 *
 * Call mddev_lock_nointr() before!
 */
static int rs_start_reshape(struct raid_set *rs)
{
	int r;
	struct mddev *mddev = &rs->md;
	struct md_personality *pers = mddev->pers;

	/* Don't allow the sync thread to work until the table gets reloaded. */
	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);

	r = rs_setup_reshape(rs);
	if (r)
		return r;

	/*
	 * Check any reshape constraints enforced by the personalility
	 *
	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
	 */
	r = pers->check_reshape(mddev);
	if (r) {
		rs->ti->error = "pers->check_reshape() failed";
		return r;
	}

	/*
	 * Personality may not provide start reshape method in which
	 * case check_reshape above has already covered everything
	 */
	if (pers->start_reshape) {
		r = pers->start_reshape(mddev);
		if (r) {
			rs->ti->error = "pers->start_reshape() failed";
			return r;
		}
	}

	/*
	 * Now reshape got set up, update superblocks to
	 * reflect the fact so that a table reload will
	 * access proper superblock content in the ctr.
	 */
	rs_update_sbs(rs);

	return 0;
}

static int raid_preresume(struct dm_target *ti)
{
	int r;
	struct raid_set *rs = ti->private;
	struct mddev *mddev = &rs->md;

	/* This is a resume after a suspend of the set -> it's already started. */
	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
		return 0;

	/*
	 * The superblocks need to be updated on disk if the
	 * array is new or new devices got added (thus zeroed
	 * out by userspace) or __load_dirty_region_bitmap
	 * will overwrite them in core with old data or fail.
	 */
	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
		rs_update_sbs(rs);

	/* Load the bitmap from disk unless raid0 */
	r = __load_dirty_region_bitmap(rs);
	if (r)
		return r;

	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
		mddev->array_sectors = rs->array_sectors;
		mddev->dev_sectors = rs->dev_sectors;
		rs_set_rdev_sectors(rs);
		rs_set_capacity(rs);
	}

	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
        if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
	     (rs->requested_bitmap_chunk_sectors &&
	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;

		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
		if (r)
			DMERR("Failed to resize bitmap");
	}

	/* Check for any resize/reshape on @rs and adjust/initiate */
	/* Be prepared for mddev_resume() in raid_resume() */
	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
		mddev->resync_min = mddev->recovery_cp;
		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
			mddev->resync_max_sectors = mddev->dev_sectors;
	}

	/* Check for any reshape request unless new raid set */
	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
		/* Initiate a reshape. */
		rs_set_rdev_sectors(rs);
		mddev_lock_nointr(mddev);
		r = rs_start_reshape(rs);
		mddev_unlock(mddev);
		if (r)
			DMWARN("Failed to check/start reshape, continuing without change");
		r = 0;
	}

	return r;
}

static void raid_resume(struct dm_target *ti)
{
	struct raid_set *rs = ti->private;
	struct mddev *mddev = &rs->md;

	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
		/*
		 * A secondary resume while the device is active.
		 * Take this opportunity to check whether any failed
		 * devices are reachable again.
		 */
		attempt_restore_of_faulty_devices(rs);
	}

	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
		/* Only reduce raid set size before running a disk removing reshape. */
		if (mddev->delta_disks < 0)
			rs_set_capacity(rs);

		mddev_lock_nointr(mddev);
		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
		mddev->ro = 0;
		mddev->in_sync = 0;
		mddev_resume(mddev);
		mddev_unlock(mddev);
	}
}

static struct target_type raid_target = {
	.name = "raid",
	.version = {1, 15, 1},
	.module = THIS_MODULE,
	.ctr = raid_ctr,
	.dtr = raid_dtr,
	.map = raid_map,
	.status = raid_status,
	.message = raid_message,
	.iterate_devices = raid_iterate_devices,
	.io_hints = raid_io_hints,
	.postsuspend = raid_postsuspend,
	.preresume = raid_preresume,
	.resume = raid_resume,
};

static int __init dm_raid_init(void)
{
	DMINFO("Loading target version %u.%u.%u",
	       raid_target.version[0],
	       raid_target.version[1],
	       raid_target.version[2]);
	return dm_register_target(&raid_target);
}

static void __exit dm_raid_exit(void)
{
	dm_unregister_target(&raid_target);
}

module_init(dm_raid_init);
module_exit(dm_raid_exit);

module_param(devices_handle_discard_safely, bool, 0644);
MODULE_PARM_DESC(devices_handle_discard_safely,
		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");

MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
MODULE_ALIAS("dm-raid0");
MODULE_ALIAS("dm-raid1");
MODULE_ALIAS("dm-raid10");
MODULE_ALIAS("dm-raid4");
MODULE_ALIAS("dm-raid5");
MODULE_ALIAS("dm-raid6");
MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");