summaryrefslogtreecommitdiffstats
path: root/fs/jffs/intrep.c
blob: ce7b54b0b2b7596333276bdcf42d40cf3011df0a (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
/*
 * JFFS -- Journaling Flash File System, Linux implementation.
 *
 * Copyright (C) 1999, 2000  Axis Communications, Inc.
 *
 * Created by Finn Hakansson <finn@axis.com>.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * $Id: intrep.c,v 1.102 2001/09/23 23:28:36 dwmw2 Exp $
 *
 * Ported to Linux 2.3.x and MTD:
 * Copyright (C) 2000  Alexander Larsson (alex@cendio.se), Cendio Systems AB
 *
 */

/* This file contains the code for the internal structure of the
   Journaling Flash File System, JFFS.  */

/*
 * Todo list:
 *
 * memcpy_to_flash() and memcpy_from_flash() functions.
 *
 * Implementation of hard links.
 *
 * Organize the source code in a better way. Against the VFS we could
 * have jffs_ext.c, and against the block device jffs_int.c.
 * A better file-internal organization too.
 *
 * A better checksum algorithm.
 *
 * Consider endianness stuff. ntohl() etc.
 *
 * Are we handling the atime, mtime, ctime members of the inode right?
 *
 * Remove some duplicated code. Take a look at jffs_write_node() and
 * jffs_rewrite_data() for instance.
 *
 * Implement more meaning of the nlink member in various data structures.
 * nlink could be used in conjunction with hard links for instance.
 *
 * Better memory management. Allocate data structures in larger chunks
 * if possible.
 *
 * If too much meta data is stored, a garbage collect should be issued.
 * We have experienced problems with too much meta data with for instance
 * log files.
 *
 * Improve the calls to jffs_ioctl(). We would like to retrieve more
 * information to be able to debug (or to supervise) JFFS during run-time.
 *
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/jffs.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/pagemap.h>
#include <asm/semaphore.h>
#include <asm/byteorder.h>
#include <linux/smp_lock.h>
#include <linux/time.h>
#include <linux/ctype.h>

#include "intrep.h"
#include "jffs_fm.h"

long no_jffs_node = 0;
static long no_jffs_file = 0;
#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
long no_jffs_control = 0;
long no_jffs_raw_inode = 0;
long no_jffs_node_ref = 0;
long no_jffs_fm = 0;
long no_jffs_fmcontrol = 0;
long no_hash = 0;
long no_name = 0;
#endif

static int jffs_scan_flash(struct jffs_control *c);
static int jffs_update_file(struct jffs_file *f, struct jffs_node *node);
static int jffs_build_file(struct jffs_file *f);
static int jffs_free_file(struct jffs_file *f);
static int jffs_free_node_list(struct jffs_file *f);
static int jffs_garbage_collect_now(struct jffs_control *c);
static int jffs_insert_file_into_hash(struct jffs_file *f);
static int jffs_remove_redundant_nodes(struct jffs_file *f);

/* Is there enough space on the flash?  */
static inline int JFFS_ENOUGH_SPACE(struct jffs_control *c, __u32 space)
{
	struct jffs_fmcontrol *fmc = c->fmc;

	while (1) {
		if ((fmc->flash_size - (fmc->used_size + fmc->dirty_size))
			>= fmc->min_free_size + space) {
			return 1;
		}
		if (fmc->dirty_size < fmc->sector_size)
			return 0;

		if (jffs_garbage_collect_now(c)) {
		  D1(printk("JFFS_ENOUGH_SPACE: jffs_garbage_collect_now() failed.\n"));
		  return 0;
		}
	}
}

#if CONFIG_JFFS_FS_VERBOSE > 0
static __u8
flash_read_u8(struct mtd_info *mtd, loff_t from)
{
	size_t retlen;
	__u8 ret;
	int res;

	res = MTD_READ(mtd, from, 1, &retlen, &ret);
	if (retlen != 1) {
		printk("Didn't read a byte in flash_read_u8(). Returned %d\n", res);
		return 0;
	}

	return ret;
}

static void
jffs_hexdump(struct mtd_info *mtd, loff_t pos, int size)
{
	char line[16];
	int j = 0;

	while (size > 0) {
		int i;

		printk("%ld:", (long) pos);
		for (j = 0; j < 16; j++) {
			line[j] = flash_read_u8(mtd, pos++);
		}
		for (i = 0; i < j; i++) {
			if (!(i & 1)) {
				printk(" %.2x", line[i] & 0xff);
			}
			else {
				printk("%.2x", line[i] & 0xff);
			}
		}

		/* Print empty space */
		for (; i < 16; i++) {
			if (!(i & 1)) {
				printk("   ");
			}
			else {
				printk("  ");
			}
		}
		printk("  ");

		for (i = 0; i < j; i++) {
			if (isgraph(line[i])) {
				printk("%c", line[i]);
			}
			else {
				printk(".");
			}
		}
		printk("\n");
		size -= 16;
	}
}

/* Print the contents of a node.  */
static void
jffs_print_node(struct jffs_node *n)
{
	D(printk("jffs_node: 0x%p\n", n));
	D(printk("{\n"));
	D(printk("        0x%08x, /* version  */\n", n->version));
	D(printk("        0x%08x, /* data_offset  */\n", n->data_offset));
	D(printk("        0x%08x, /* data_size  */\n", n->data_size));
	D(printk("        0x%08x, /* removed_size  */\n", n->removed_size));
	D(printk("        0x%08x, /* fm_offset  */\n", n->fm_offset));
	D(printk("        0x%02x,       /* name_size  */\n", n->name_size));
	D(printk("        0x%p, /* fm,  fm->offset: %u  */\n",
		 n->fm, (n->fm ? n->fm->offset : 0)));
	D(printk("        0x%p, /* version_prev  */\n", n->version_prev));
	D(printk("        0x%p, /* version_next  */\n", n->version_next));
	D(printk("        0x%p, /* range_prev  */\n", n->range_prev));
	D(printk("        0x%p, /* range_next  */\n", n->range_next));
	D(printk("}\n"));
}

#endif

/* Print the contents of a raw inode.  */
static void
jffs_print_raw_inode(struct jffs_raw_inode *raw_inode)
{
	D(printk("jffs_raw_inode: inode number: %u\n", raw_inode->ino));
	D(printk("{\n"));
	D(printk("        0x%08x, /* magic  */\n", raw_inode->magic));
	D(printk("        0x%08x, /* ino  */\n", raw_inode->ino));
	D(printk("        0x%08x, /* pino  */\n", raw_inode->pino));
	D(printk("        0x%08x, /* version  */\n", raw_inode->version));
	D(printk("        0x%08x, /* mode  */\n", raw_inode->mode));
	D(printk("        0x%04x,     /* uid  */\n", raw_inode->uid));
	D(printk("        0x%04x,     /* gid  */\n", raw_inode->gid));
	D(printk("        0x%08x, /* atime  */\n", raw_inode->atime));
	D(printk("        0x%08x, /* mtime  */\n", raw_inode->mtime));
	D(printk("        0x%08x, /* ctime  */\n", raw_inode->ctime));
	D(printk("        0x%08x, /* offset  */\n", raw_inode->offset));
	D(printk("        0x%08x, /* dsize  */\n", raw_inode->dsize));
	D(printk("        0x%08x, /* rsize  */\n", raw_inode->rsize));
	D(printk("        0x%02x,       /* nsize  */\n", raw_inode->nsize));
	D(printk("        0x%02x,       /* nlink  */\n", raw_inode->nlink));
	D(printk("        0x%02x,       /* spare  */\n",
		 raw_inode->spare));
	D(printk("        %u,          /* rename  */\n",
		 raw_inode->rename));
	D(printk("        %u,          /* deleted  */\n",
		 raw_inode->deleted));
	D(printk("        0x%02x,       /* accurate  */\n",
		 raw_inode->accurate));
	D(printk("        0x%08x, /* dchksum  */\n", raw_inode->dchksum));
	D(printk("        0x%04x,     /* nchksum  */\n", raw_inode->nchksum));
	D(printk("        0x%04x,     /* chksum  */\n", raw_inode->chksum));
	D(printk("}\n"));
}

#define flash_safe_acquire(arg)
#define flash_safe_release(arg)


static int
flash_safe_read(struct mtd_info *mtd, loff_t from,
		u_char *buf, size_t count)
{
	size_t retlen;
	int res;

	D3(printk(KERN_NOTICE "flash_safe_read(%p, %08x, %p, %08x)\n",
		  mtd, (unsigned int) from, buf, count));

	res = MTD_READ(mtd, from, count, &retlen, buf);
	if (retlen != count) {
		panic("Didn't read all bytes in flash_safe_read(). Returned %d\n", res);
	}
	return res?res:retlen;
}


static __u32
flash_read_u32(struct mtd_info *mtd, loff_t from)
{
	size_t retlen;
	__u32 ret;
	int res;

	res = MTD_READ(mtd, from, 4, &retlen, (unsigned char *)&ret);
	if (retlen != 4) {
		printk("Didn't read all bytes in flash_read_u32(). Returned %d\n", res);
		return 0;
	}

	return ret;
}


static int
flash_safe_write(struct mtd_info *mtd, loff_t to,
		 const u_char *buf, size_t count)
{
	size_t retlen;
	int res;

	D3(printk(KERN_NOTICE "flash_safe_write(%p, %08x, %p, %08x)\n",
		  mtd, (unsigned int) to, buf, count));

	res = MTD_WRITE(mtd, to, count, &retlen, buf);
	if (retlen != count) {
		printk("Didn't write all bytes in flash_safe_write(). Returned %d\n", res);
	}
	return res?res:retlen;
}


static int
flash_safe_writev(struct mtd_info *mtd, const struct kvec *vecs,
			unsigned long iovec_cnt, loff_t to)
{
	size_t retlen, retlen_a;
	int i;
	int res;

	D3(printk(KERN_NOTICE "flash_safe_writev(%p, %08x, %p)\n",
		  mtd, (unsigned int) to, vecs));
	
	if (mtd->writev) {
		res = MTD_WRITEV(mtd, vecs, iovec_cnt, to, &retlen);
		return res ? res : retlen;
	}
	/* Not implemented writev. Repeatedly use write - on the not so
	   unreasonable assumption that the mtd driver doesn't care how
	   many write cycles we use. */
	res=0;
	retlen=0;

	for (i=0; !res && i<iovec_cnt; i++) {
		res = MTD_WRITE(mtd, to, vecs[i].iov_len, &retlen_a, vecs[i].iov_base);
		if (retlen_a != vecs[i].iov_len) {
			printk("Didn't write all bytes in flash_safe_writev(). Returned %d\n", res);
			if (i != iovec_cnt-1)
				return -EIO;
		}
		/* If res is non-zero, retlen_a is undefined, but we don't
		   care because in that case it's not going to be 
		   returned anyway.
		*/
		to += retlen_a;
		retlen += retlen_a;
	}
	return res?res:retlen;
}


static int
flash_memset(struct mtd_info *mtd, loff_t to,
	     const u_char c, size_t size)
{
	static unsigned char pattern[64];
	int i;

	/* fill up pattern */

	for(i = 0; i < 64; i++)
		pattern[i] = c;

	/* write as many 64-byte chunks as we can */

	while (size >= 64) {
		flash_safe_write(mtd, to, pattern, 64);
		size -= 64;
		to += 64;
	}

	/* and the rest */

	if(size)
		flash_safe_write(mtd, to, pattern, size);

	return size;
}


static void
intrep_erase_callback(struct erase_info *done)
{
	wait_queue_head_t *wait_q;

	wait_q = (wait_queue_head_t *)done->priv;

	wake_up(wait_q);
}


static int
flash_erase_region(struct mtd_info *mtd, loff_t start,
		   size_t size)
{
	struct erase_info *erase;
	DECLARE_WAITQUEUE(wait, current);
	wait_queue_head_t wait_q;

	erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
	if (!erase)
		return -ENOMEM;

	init_waitqueue_head(&wait_q);

	erase->mtd = mtd;
	erase->callback = intrep_erase_callback;
	erase->addr = start;
	erase->len = size;
	erase->priv = (u_long)&wait_q;

	/* FIXME: Use TASK_INTERRUPTIBLE and deal with being interrupted */
	set_current_state(TASK_UNINTERRUPTIBLE);
	add_wait_queue(&wait_q, &wait);

	if (MTD_ERASE(mtd, erase) < 0) {
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&wait_q, &wait);
		kfree(erase);

		printk(KERN_WARNING "flash: erase of region [0x%lx, 0x%lx] "
		       "totally failed\n", (long)start, (long)start + size);

		return -1;
	}

	schedule(); /* Wait for flash to finish. */
	remove_wait_queue(&wait_q, &wait);

	kfree(erase);

	return 0;
}

/* This routine calculates checksums in JFFS.  */
static __u32
jffs_checksum(const void *data, int size)
{
	__u32 sum = 0;
	__u8 *ptr = (__u8 *)data;
	while (size-- > 0) {
		sum += *ptr++;
	}
	D3(printk(", result: 0x%08x\n", sum));
	return sum;
}


static int
jffs_checksum_flash(struct mtd_info *mtd, loff_t start, int size, __u32 *result)
{
	__u32 sum = 0;
	loff_t ptr = start;
	__u8 *read_buf;
	int i, length;

	/* Allocate read buffer */
	read_buf = (__u8 *) kmalloc (sizeof(__u8) * 4096, GFP_KERNEL);
	if (!read_buf) {
		printk(KERN_NOTICE "kmalloc failed in jffs_checksum_flash()\n");
		return -ENOMEM;
	}
	/* Loop until checksum done */
	while (size) {
		/* Get amount of data to read */
		if (size < 4096)
			length = size;
		else
			length = 4096;

		/* Perform flash read */
		D3(printk(KERN_NOTICE "jffs_checksum_flash\n"));
		flash_safe_read(mtd, ptr, &read_buf[0], length);

		/* Compute checksum */
		for (i=0; i < length ; i++)
			sum += read_buf[i];

		/* Update pointer and size */
		size -= length;
		ptr += length;
	}

	/* Free read buffer */
	kfree(read_buf);

	/* Return result */
	D3(printk("checksum result: 0x%08x\n", sum));
	*result = sum;
	return 0;
}

static __inline__ void jffs_fm_write_lock(struct jffs_fmcontrol *fmc)
{
  //	down(&fmc->wlock);
}

static __inline__ void jffs_fm_write_unlock(struct jffs_fmcontrol *fmc)
{
  //	up(&fmc->wlock);
}


/* Create and initialize a new struct jffs_file.  */
static struct jffs_file *
jffs_create_file(struct jffs_control *c,
		 const struct jffs_raw_inode *raw_inode)
{
	struct jffs_file *f;

	if (!(f = (struct jffs_file *)kmalloc(sizeof(struct jffs_file),
					      GFP_KERNEL))) {
		D(printk("jffs_create_file(): Failed!\n"));
		return NULL;
	}
	no_jffs_file++;
	memset(f, 0, sizeof(struct jffs_file));
	f->ino = raw_inode->ino;
	f->pino = raw_inode->pino;
	f->nlink = raw_inode->nlink;
	f->deleted = raw_inode->deleted;
	f->c = c;

	return f;
}


/* Build a control block for the file system.  */
static struct jffs_control *
jffs_create_control(struct super_block *sb)
{
	struct jffs_control *c;
	register int s = sizeof(struct jffs_control);
	int i;
	D(char *t = 0);

	D2(printk("jffs_create_control()\n"));

	if (!(c = (struct jffs_control *)kmalloc(s, GFP_KERNEL))) {
		goto fail_control;
	}
	DJM(no_jffs_control++);
	c->root = NULL;
	c->gc_task = NULL;
	c->hash_len = JFFS_HASH_SIZE;
	s = sizeof(struct list_head) * c->hash_len;
	if (!(c->hash = (struct list_head *)kmalloc(s, GFP_KERNEL))) {
		goto fail_hash;
	}
	DJM(no_hash++);
	for (i = 0; i < c->hash_len; i++)
		INIT_LIST_HEAD(&c->hash[i]);
	if (!(c->fmc = jffs_build_begin(c, MINOR(sb->s_dev)))) {
		goto fail_fminit;
	}
	c->next_ino = JFFS_MIN_INO + 1;
	c->delete_list = (struct jffs_delete_list *) 0;
	return c;

fail_fminit:
	D(t = "c->fmc");
fail_hash:
	kfree(c);
	DJM(no_jffs_control--);
	D(t = t ? t : "c->hash");
fail_control:
	D(t = t ? t : "control");
	D(printk("jffs_create_control(): Allocation failed: (%s)\n", t));
	return (struct jffs_control *)0;
}


/* Clean up all data structures associated with the file system.  */
void
jffs_cleanup_control(struct jffs_control *c)
{
	D2(printk("jffs_cleanup_control()\n"));

	if (!c) {
		D(printk("jffs_cleanup_control(): c == NULL !!!\n"));
		return;
	}

	while (c->delete_list) {
		struct jffs_delete_list *delete_list_element;
		delete_list_element = c->delete_list;
		c->delete_list = c->delete_list->next;
		kfree(delete_list_element);
	}

	/* Free all files and nodes.  */
	if (c->hash) {
		jffs_foreach_file(c, jffs_free_node_list);
		jffs_foreach_file(c, jffs_free_file);
		kfree(c->hash);
		DJM(no_hash--);
	}
	jffs_cleanup_fmcontrol(c->fmc);
	kfree(c);
	DJM(no_jffs_control--);
	D3(printk("jffs_cleanup_control(): Leaving...\n"));
}


/* This function adds a virtual root node to the in-RAM representation.
   Called by jffs_build_fs().  */
static int
jffs_add_virtual_root(struct jffs_control *c)
{
	struct jffs_file *root;
	struct jffs_node *node;

	D2(printk("jffs_add_virtual_root(): "
		  "Creating a virtual root directory.\n"));

	if (!(root = (struct jffs_file *)kmalloc(sizeof(struct jffs_file),
						 GFP_KERNEL))) {
		return -ENOMEM;
	}
	no_jffs_file++;
	if (!(node = jffs_alloc_node())) {
		kfree(root);
		no_jffs_file--;
		return -ENOMEM;
	}
	DJM(no_jffs_node++);
	memset(node, 0, sizeof(struct jffs_node));
	node->ino = JFFS_MIN_INO;
	memset(root, 0, sizeof(struct jffs_file));
	root->ino = JFFS_MIN_INO;
	root->mode = S_IFDIR | S_IRWXU | S_IRGRP
		     | S_IXGRP | S_IROTH | S_IXOTH;
	root->atime = root->mtime = root->ctime = get_seconds();
	root->nlink = 1;
	root->c = c;
	root->version_head = root->version_tail = node;
	jffs_insert_file_into_hash(root);
	return 0;
}


/* This is where the file system is built and initialized.  */
int
jffs_build_fs(struct super_block *sb)
{
	struct jffs_control *c;
	int err = 0;

	D2(printk("jffs_build_fs()\n"));

	if (!(c = jffs_create_control(sb))) {
		return -ENOMEM;
	}
	c->building_fs = 1;
	c->sb = sb;
	if ((err = jffs_scan_flash(c)) < 0) {
		if(err == -EAGAIN){
			/* scan_flash() wants us to try once more. A flipping 
			   bits sector was detect in the middle of the scan flash.
			   Clean up old allocated memory before going in.
			*/
			D1(printk("jffs_build_fs: Cleaning up all control structures,"
				  " reallocating them and trying mount again.\n"));
			jffs_cleanup_control(c);
			if (!(c = jffs_create_control(sb))) {
				return -ENOMEM;
			}
			c->building_fs = 1;
			c->sb = sb;

			if ((err = jffs_scan_flash(c)) < 0) {
				goto jffs_build_fs_fail;
			}			
		}else{
			goto jffs_build_fs_fail;
		}
	}

	/* Add a virtual root node if no one exists.  */
	if (!jffs_find_file(c, JFFS_MIN_INO)) {
		if ((err = jffs_add_virtual_root(c)) < 0) {
			goto jffs_build_fs_fail;
		}
	}

	while (c->delete_list) {
		struct jffs_file *f;
		struct jffs_delete_list *delete_list_element;

		if ((f = jffs_find_file(c, c->delete_list->ino))) {
			f->deleted = 1;
		}
		delete_list_element = c->delete_list;
		c->delete_list = c->delete_list->next;
		kfree(delete_list_element);
	}

	/* Remove deleted nodes.  */
	if ((err = jffs_foreach_file(c, jffs_possibly_delete_file)) < 0) {
		printk(KERN_ERR "JFFS: Failed to remove deleted nodes.\n");
		goto jffs_build_fs_fail;
	}
	/* Remove redundant nodes.  (We are not interested in the
	   return value in this case.)  */
	jffs_foreach_file(c, jffs_remove_redundant_nodes);
	/* Try to build a tree from all the nodes.  */
	if ((err = jffs_foreach_file(c, jffs_insert_file_into_tree)) < 0) {
		printk("JFFS: Failed to build tree.\n");
		goto jffs_build_fs_fail;
	}
	/* Compute the sizes of all files in the filesystem.  Adjust if
	   necessary.  */
	if ((err = jffs_foreach_file(c, jffs_build_file)) < 0) {
		printk("JFFS: Failed to build file system.\n");
		goto jffs_build_fs_fail;
	}
	sb->s_fs_info = (void *)c;
	c->building_fs = 0;

	D1(jffs_print_hash_table(c));
	D1(jffs_print_tree(c->root, 0));

	return 0;

jffs_build_fs_fail:
	jffs_cleanup_control(c);
	return err;
} /* jffs_build_fs()  */


/*
  This checks for sectors that were being erased in their previous 
  lifetimes and for some reason or the other (power fail etc.), 
  the erase cycles never completed.
  As the flash array would have reverted back to read status, 
  these sectors are detected by the symptom of the "flipping bits",
  i.e. bits being read back differently from the same location in
  flash if read multiple times.
  The only solution to this is to re-erase the entire
  sector.
  Unfortunately detecting "flipping bits" is not a simple exercise
  as a bit may be read back at 1 or 0 depending on the alignment 
  of the stars in the universe.
  The level of confidence is in direct proportion to the number of 
  scans done. By power fail testing I (Vipin) have been able to 
  proove that reading twice is not enough.
  Maybe 4 times? Change NUM_REREADS to a higher number if you want
  a (even) higher degree of confidence in your mount process. 
  A higher number would of course slow down your mount.
*/
static int check_partly_erased_sectors(struct jffs_fmcontrol *fmc){

#define NUM_REREADS             4 /* see note above */
#define READ_AHEAD_BYTES        4096 /* must be a multiple of 4, 
					usually set to kernel page size */

	__u8 *read_buf1;
	__u8 *read_buf2;

	int err = 0;
	int retlen;
	int i;
	int cnt;
	__u32 offset;
	loff_t pos = 0;
	loff_t end = fmc->flash_size;


	/* Allocate read buffers */
	read_buf1 = (__u8 *) kmalloc (sizeof(__u8) * READ_AHEAD_BYTES, GFP_KERNEL);
	if (!read_buf1)
		return -ENOMEM;

	read_buf2 = (__u8 *) kmalloc (sizeof(__u8) * READ_AHEAD_BYTES, GFP_KERNEL);
	if (!read_buf2) {
		kfree(read_buf1);
		return -ENOMEM;
	}

 CHECK_NEXT:
	while(pos < end){
		
		D1(printk("check_partly_erased_sector():checking sector which contains"
			  " offset 0x%x for flipping bits..\n", (__u32)pos));
		
		retlen = flash_safe_read(fmc->mtd, pos,
					 &read_buf1[0], READ_AHEAD_BYTES);
		retlen &= ~3;
		
		for(cnt = 0; cnt < NUM_REREADS; cnt++){
			(void)flash_safe_read(fmc->mtd, pos,
					      &read_buf2[0], READ_AHEAD_BYTES);
			
			for (i=0 ; i < retlen ; i+=4) {
				/* buffers MUST match, double word for word! */
				if(*((__u32 *) &read_buf1[i]) !=
				   *((__u32 *) &read_buf2[i])
				   ){
				        /* flipping bits detected, time to erase sector */
					/* This will help us log some statistics etc. */
					D1(printk("Flipping bits detected in re-read round:%i of %i\n",
					       cnt, NUM_REREADS));
					D1(printk("check_partly_erased_sectors:flipping bits detected"
						  " @offset:0x%x(0x%x!=0x%x)\n",
						  (__u32)pos+i, *((__u32 *) &read_buf1[i]), 
						  *((__u32 *) &read_buf2[i])));
					
				        /* calculate start of present sector */
					offset = (((__u32)pos+i)/(__u32)fmc->sector_size) * (__u32)fmc->sector_size;
					
					D1(printk("check_partly_erased_sector():erasing sector starting 0x%x.\n",
						  offset));
					
					if (flash_erase_region(fmc->mtd,
							       offset, fmc->sector_size) < 0) {
						printk(KERN_ERR "JFFS: Erase of flash failed. "
						       "offset = %u, erase_size = %d\n",
						       offset , fmc->sector_size);
						
						err = -EIO;
						goto returnBack;

					}else{
						D1(printk("JFFS: Erase of flash sector @0x%x successful.\n",
						       offset));
						/* skip ahead to the next sector */
						pos = (((__u32)pos+i)/(__u32)fmc->sector_size) * (__u32)fmc->sector_size;
						pos += fmc->sector_size;
						goto CHECK_NEXT;
					}
				}
			}
		}
		pos += READ_AHEAD_BYTES;
	}

 returnBack:
	kfree(read_buf1);
	kfree(read_buf2);

	D2(printk("check_partly_erased_sector():Done checking all sectors till offset 0x%x for flipping bits.\n",
		  (__u32)pos));

	return err;

}/* end check_partly_erased_sectors() */



/* Scan the whole flash memory in order to find all nodes in the
   file systems.  */
static int
jffs_scan_flash(struct jffs_control *c)
{
	char name[JFFS_MAX_NAME_LEN + 2];
	struct jffs_raw_inode raw_inode;
	struct jffs_node *node = NULL;
	struct jffs_fmcontrol *fmc = c->fmc;
	__u32 checksum;
	__u8 tmp_accurate;
	__u16 tmp_chksum;
	__u32 deleted_file;
	loff_t pos = 0;
	loff_t start;
	loff_t test_start;
	loff_t end = fmc->flash_size;
	__u8 *read_buf;
	int i, len, retlen;
	__u32 offset;

	__u32 free_chunk_size1;
	__u32 free_chunk_size2;

	
#define NUMFREEALLOWED     2        /* 2 chunks of at least erase size space allowed */
	int num_free_space = 0;       /* Flag err if more than TWO
				       free blocks found. This is NOT allowed
				       by the current jffs design.
				    */
	int num_free_spc_not_accp = 0; /* For debugging purposed keep count 
					of how much free space was rejected and
					marked dirty
				     */

	D1(printk("jffs_scan_flash(): start pos = 0x%lx, end = 0x%lx\n",
		  (long)pos, (long)end));

	flash_safe_acquire(fmc->mtd);

	/*
	  check and make sure that any sector does not suffer
	  from the "partly erased, bit flipping syndrome" (TM Vipin :)
	  If so, offending sectors will be erased.
	*/
	if(check_partly_erased_sectors(fmc) < 0){

		flash_safe_release(fmc->mtd);
		return -EIO; /* bad, bad, bad error. Cannot continue.*/
	}

	/* Allocate read buffer */
	read_buf = (__u8 *) kmalloc (sizeof(__u8) * 4096, GFP_KERNEL);
	if (!read_buf) {
		flash_safe_release(fmc->mtd);
		return -ENOMEM;
	}
			      
	/* Start the scan.  */
	while (pos < end) {
		deleted_file = 0;

		/* Remember the position from where we started this scan.  */
		start = pos;

		switch (flash_read_u32(fmc->mtd, pos)) {
		case JFFS_EMPTY_BITMASK:
			/* We have found 0xffffffff at this position.  We have to
			   scan the rest of the flash till the end or till
			   something else than 0xffffffff is found.
		           Keep going till we do not find JFFS_EMPTY_BITMASK 
			   anymore */

			D1(printk("jffs_scan_flash(): 0xffffffff at pos 0x%lx.\n",
				  (long)pos));

		        while(pos < end){

			      len = end - pos < 4096 ? end - pos : 4096;
			      
			      retlen = flash_safe_read(fmc->mtd, pos,
						 &read_buf[0], len);

			      retlen &= ~3;
			      
			      for (i=0 ; i < retlen ; i+=4, pos += 4) {
				      if(*((__u32 *) &read_buf[i]) !=
					 JFFS_EMPTY_BITMASK)
					break;
			      }
			      if (i == retlen)
				    continue;
			      else
				    break;
			}

			D1(printk("jffs_scan_flash():0xffffffff ended at pos 0x%lx.\n",
				  (long)pos));
			
			/* If some free space ends in the middle of a sector,
			   treat it as dirty rather than clean.
			   This is to handle the case where one thread 
			   allocated space for a node, but didn't get to
			   actually _write_ it before power was lost, leaving
			   a gap in the log. Shifting all node writes into
			   a single kernel thread will fix the original problem.
			*/
			if ((__u32) pos % fmc->sector_size) {
				/* If there was free space in previous 
				   sectors, don't mark that dirty too - 
				   only from the beginning of this sector
				   (or from start) 
				*/

			        test_start = pos & ~(fmc->sector_size-1); /* end of last sector */

				if (start < test_start) {

				        /* free space started in the previous sector! */

					if((num_free_space < NUMFREEALLOWED) && 
					   ((unsigned int)(test_start - start) >= fmc->sector_size)){

				                /*
						  Count it in if we are still under NUMFREEALLOWED *and* it is 
						  at least 1 erase sector in length. This will keep us from 
						  picking any little ole' space as "free".
						*/
					  
					        D1(printk("Reducing end of free space to 0x%x from 0x%x\n",
							  (unsigned int)test_start, (unsigned int)pos));

						D1(printk("Free space accepted: Starting 0x%x for 0x%x bytes\n",
							  (unsigned int) start,
							  (unsigned int)(test_start - start)));

						/* below, space from "start" to "pos" will be marked dirty. */
						start = test_start; 
						
						/* Being in here means that we have found at least an entire 
						   erase sector size of free space ending on a sector boundary.
						   Keep track of free spaces accepted.
						*/
						num_free_space++;
					}else{
					        num_free_spc_not_accp++;
					        D1(printk("Free space (#%i) found but *Not* accepted: Starting"
							  " 0x%x for 0x%x bytes\n",
							  num_free_spc_not_accp, (unsigned int)start, 
							  (unsigned int)((unsigned int)(pos & ~(fmc->sector_size-1)) - (unsigned int)start)));
					        
					}
					
				}
				if((((__u32)(pos - start)) != 0)){

				        D1(printk("Dirty space: Starting 0x%x for 0x%x bytes\n",
						  (unsigned int) start, (unsigned int) (pos - start)));
					jffs_fmalloced(fmc, (__u32) start,
						       (__u32) (pos - start), NULL);
				}else{
					/* "Flipping bits" detected. This means that our scan for them
					   did not catch this offset. See check_partly_erased_sectors() for
					   more info.
					*/
				        
					D1(printk("jffs_scan_flash():wants to allocate dirty flash "
						  "space for 0 bytes.\n"));
					D1(printk("jffs_scan_flash(): Flipping bits! We will free "
						  "all allocated memory, erase this sector and remount\n"));

					/* calculate start of present sector */
					offset = (((__u32)pos)/(__u32)fmc->sector_size) * (__u32)fmc->sector_size;
					
					D1(printk("jffs_scan_flash():erasing sector starting 0x%x.\n",
						  offset));
					
					if (flash_erase_region(fmc->mtd,
							       offset, fmc->sector_size) < 0) {
						printk(KERN_ERR "JFFS: Erase of flash failed. "
						       "offset = %u, erase_size = %d\n",
						       offset , fmc->sector_size);

						flash_safe_release(fmc->mtd);
						kfree(read_buf);
						return -1; /* bad, bad, bad! */

					}
					flash_safe_release(fmc->mtd);
					kfree(read_buf);

					return -EAGAIN; /* erased offending sector. Try mount one more time please. */
				}
			}else{
			        /* Being in here means that we have found free space that ends on an erase sector
				   boundary.
				   Count it in if we are still under NUMFREEALLOWED *and* it is at least 1 erase 
				   sector in length. This will keep us from picking any little ole' space as "free".
				 */
			         if((num_free_space < NUMFREEALLOWED) && 
				    ((unsigned int)(pos - start) >= fmc->sector_size)){
				           /* We really don't do anything to mark space as free, except *not* 
					      mark it dirty and just advance the "pos" location pointer. 
					      It will automatically be picked up as free space.
					    */ 
				           num_free_space++;
				           D1(printk("Free space accepted: Starting 0x%x for 0x%x bytes\n",
						     (unsigned int) start, (unsigned int) (pos - start)));
				 }else{
				         num_free_spc_not_accp++;
					 D1(printk("Free space (#%i) found but *Not* accepted: Starting "
						   "0x%x for 0x%x bytes\n", num_free_spc_not_accp, 
						   (unsigned int) start, 
						   (unsigned int) (pos - start)));
					 
					 /* Mark this space as dirty. We already have our free space. */
					 D1(printk("Dirty space: Starting 0x%x for 0x%x bytes\n",
						   (unsigned int) start, (unsigned int) (pos - start)));
					 jffs_fmalloced(fmc, (__u32) start,
							(__u32) (pos - start), NULL);				           
				 }
				 
			}
			if(num_free_space > NUMFREEALLOWED){
			         printk(KERN_WARNING "jffs_scan_flash(): Found free space "
					"number %i. Only %i free space is allowed.\n",
					num_free_space, NUMFREEALLOWED);			      
			}
			continue;

		case JFFS_DIRTY_BITMASK:
			/* We have found 0x00000000 at this position.  Scan as far
			   as possible to find out how much is dirty.  */
			D1(printk("jffs_scan_flash(): 0x00000000 at pos 0x%lx.\n",
				  (long)pos));
			for (; pos < end
			       && JFFS_DIRTY_BITMASK == flash_read_u32(fmc->mtd, pos);
			     pos += 4);
			D1(printk("jffs_scan_flash(): 0x00 ended at "
				  "pos 0x%lx.\n", (long)pos));
			jffs_fmalloced(fmc, (__u32) start,
				       (__u32) (pos - start), NULL);
			continue;

		case JFFS_MAGIC_BITMASK:
			/* We have probably found a new raw inode.  */
			break;

		default:
		bad_inode:
			/* We're f*cked.  This is not solved yet.  We have
			   to scan for the magic pattern.  */
			D1(printk("*************** Dirty flash memory or "
				  "bad inode: "
				  "hexdump(pos = 0x%lx, len = 128):\n",
				  (long)pos));
			D1(jffs_hexdump(fmc->mtd, pos, 128));

			for (pos += 4; pos < end; pos += 4) {
				switch (flash_read_u32(fmc->mtd, pos)) {
				case JFFS_MAGIC_BITMASK:
				case JFFS_EMPTY_BITMASK:
					/* handle these in the main switch() loop */
					goto cont_scan;

				default:
					break;
				}
			}

			cont_scan:
			/* First, mark as dirty the region
			   which really does contain crap. */
			jffs_fmalloced(fmc, (__u32) start,
				       (__u32) (pos - start),
				       NULL);
			
			continue;
		}/* switch */

		/* We have found the beginning of an inode.  Create a
		   node for it unless there already is one available.  */
		if (!node) {
			if (!(node = jffs_alloc_node())) {
				/* Free read buffer */
				kfree(read_buf);

				/* Release the flash device */
				flash_safe_release(fmc->mtd);
	
				return -ENOMEM;
			}
			DJM(no_jffs_node++);
		}

		/* Read the next raw inode.  */

		flash_safe_read(fmc->mtd, pos, (u_char *) &raw_inode,
				sizeof(struct jffs_raw_inode));

		/* When we compute the checksum for the inode, we never
		   count the 'accurate' or the 'checksum' fields.  */
		tmp_accurate = raw_inode.accurate;
		tmp_chksum = raw_inode.chksum;
		raw_inode.accurate = 0;
		raw_inode.chksum = 0;
		checksum = jffs_checksum(&raw_inode,
					 sizeof(struct jffs_raw_inode));
		raw_inode.accurate = tmp_accurate;
		raw_inode.chksum = tmp_chksum;

		D3(printk("*** We have found this raw inode at pos 0x%lx "
			  "on the flash:\n", (long)pos));
		D3(jffs_print_raw_inode(&raw_inode));

		if (checksum != raw_inode.chksum) {
			D1(printk("jffs_scan_flash(): Bad checksum: "
				  "checksum = %u, "
				  "raw_inode.chksum = %u\n",
				  checksum, raw_inode.chksum));
			pos += sizeof(struct jffs_raw_inode);
			jffs_fmalloced(fmc, (__u32) start,
				       (__u32) (pos - start), NULL);
			/* Reuse this unused struct jffs_node.  */
			continue;
		}

		/* Check the raw inode read so far.  Start with the
		   maximum length of the filename.  */
		if (raw_inode.nsize > JFFS_MAX_NAME_LEN) {
			printk(KERN_WARNING "jffs_scan_flash: Found a "
			       "JFFS node with name too large\n");
			goto bad_inode;
		}

		if (raw_inode.rename && raw_inode.dsize != sizeof(__u32)) {
			printk(KERN_WARNING "jffs_scan_flash: Found a "
			       "rename node with dsize %u.\n",
			       raw_inode.dsize);
			jffs_print_raw_inode(&raw_inode);
			goto bad_inode;
		}

		/* The node's data segment should not exceed a
		   certain length.  */
		if (raw_inode.dsize > fmc->max_chunk_size) {
			printk(KERN_WARNING "jffs_scan_flash: Found a "
			       "JFFS node with dsize (0x%x) > max_chunk_size (0x%x)\n",
			       raw_inode.dsize, fmc->max_chunk_size);
			goto bad_inode;
		}

		pos += sizeof(struct jffs_raw_inode);

		/* This shouldn't be necessary because a node that
		   violates the flash boundaries shouldn't be written
		   in the first place. */
		if (pos >= end) {
			goto check_node;
		}

		/* Read the name.  */
		*name = 0;
		if (raw_inode.nsize) {
		        flash_safe_read(fmc->mtd, pos, name, raw_inode.nsize);
			name[raw_inode.nsize] = '\0';
			pos += raw_inode.nsize
			       + JFFS_GET_PAD_BYTES(raw_inode.nsize);
			D3(printk("name == \"%s\"\n", name));
			checksum = jffs_checksum(name, raw_inode.nsize);
			if (checksum != raw_inode.nchksum) {
				D1(printk("jffs_scan_flash(): Bad checksum: "
					  "checksum = %u, "
					  "raw_inode.nchksum = %u\n",
					  checksum, raw_inode.nchksum));
				jffs_fmalloced(fmc, (__u32) start,
					       (__u32) (pos - start), NULL);
				/* Reuse this unused struct jffs_node.  */
				continue;
			}
			if (pos >= end) {
				goto check_node;
			}
		}

		/* Read the data, if it exists, in order to be sure it
		   matches the checksum.  */
		if (raw_inode.dsize) {
			if (raw_inode.rename) {
				deleted_file = flash_read_u32(fmc->mtd, pos);
			}
			if (jffs_checksum_flash(fmc->mtd, pos, raw_inode.dsize, &checksum)) {
				printk("jffs_checksum_flash() failed to calculate a checksum\n");
				jffs_fmalloced(fmc, (__u32) start,
					       (__u32) (pos - start), NULL);
				/* Reuse this unused struct jffs_node.  */
				continue;
			}				
			pos += raw_inode.dsize
			       + JFFS_GET_PAD_BYTES(raw_inode.dsize);

			if (checksum != raw_inode.dchksum) {
				D1(printk("jffs_scan_flash(): Bad checksum: "
					  "checksum = %u, "
					  "raw_inode.dchksum = %u\n",
					  checksum, raw_inode.dchksum));
				jffs_fmalloced(fmc, (__u32) start,
					       (__u32) (pos - start), NULL);
				/* Reuse this unused struct jffs_node.  */
				continue;
			}
		}

		check_node:

		/* Remember the highest inode number in the whole file
		   system.  This information will be used when assigning
		   new files new inode numbers.  */
		if (c->next_ino <= raw_inode.ino) {
			c->next_ino = raw_inode.ino + 1;
		}

		if (raw_inode.accurate) {
			int err;
			node->data_offset = raw_inode.offset;
			node->data_size = raw_inode.dsize;
			node->removed_size = raw_inode.rsize;
			/* Compute the offset to the actual data in the
			   on-flash node.  */
			node->fm_offset
			= sizeof(struct jffs_raw_inode)
			  + raw_inode.nsize
			  + JFFS_GET_PAD_BYTES(raw_inode.nsize);
			node->fm = jffs_fmalloced(fmc, (__u32) start,
						  (__u32) (pos - start),
						  node);
			if (!node->fm) {
				D(printk("jffs_scan_flash(): !node->fm\n"));
				jffs_free_node(node);
				DJM(no_jffs_node--);

				/* Free read buffer */
				kfree(read_buf);

				/* Release the flash device */
				flash_safe_release(fmc->mtd);

				return -ENOMEM;
			}
			if ((err = jffs_insert_node(c, NULL, &raw_inode,
						    name, node)) < 0) {
				printk("JFFS: Failed to handle raw inode. "
				       "(err = %d)\n", err);
				break;
			}
			if (raw_inode.rename) {
				struct jffs_delete_list *dl
				= (struct jffs_delete_list *)
				  kmalloc(sizeof(struct jffs_delete_list),
					  GFP_KERNEL);
				if (!dl) {
					D(printk("jffs_scan_flash: !dl\n"));
					jffs_free_node(node);
					DJM(no_jffs_node--);

					/* Release the flash device */
					flash_safe_release(fmc->flash_part);

					/* Free read buffer */
					kfree(read_buf);

					return -ENOMEM;
				}
				dl->ino = deleted_file;
				dl->next = c->delete_list;
				c->delete_list = dl;
				node->data_size = 0;
			}
			D3(jffs_print_node(node));
			node = NULL; /* Don't free the node!  */
		}
		else {
			jffs_fmalloced(fmc, (__u32) start,
				       (__u32) (pos - start), NULL);
			D3(printk("jffs_scan_flash(): Just found an obsolete "
				  "raw_inode. Continuing the scan...\n"));
			/* Reuse this unused struct jffs_node.  */
		}
	}

	if (node) {
		jffs_free_node(node);
		DJM(no_jffs_node--);
	}
	jffs_build_end(fmc);

	/* Free read buffer */
	kfree(read_buf);

	if(!num_free_space){
	        printk(KERN_WARNING "jffs_scan_flash(): Did not find even a single "
		       "chunk of free space. This is BAD!\n");
	}

	/* Return happy */
	D3(printk("jffs_scan_flash(): Leaving...\n"));
	flash_safe_release(fmc->mtd);

	/* This is to trap the "free size accounting screwed error. */
	free_chunk_size1 = jffs_free_size1(fmc);
	free_chunk_size2 = jffs_free_size2(fmc);

	if (free_chunk_size1 + free_chunk_size2 != fmc->free_size) {

		printk(KERN_WARNING "jffs_scan_falsh():Free size accounting screwed\n");
		printk(KERN_WARNING "jfffs_scan_flash():free_chunk_size1 == 0x%x, "
		       "free_chunk_size2 == 0x%x, fmc->free_size == 0x%x\n", 
		       free_chunk_size1, free_chunk_size2, fmc->free_size);

		return -1; /* Do NOT mount f/s so that we can inspect what happened.
			      Mounting this  screwed up f/s will screw us up anyway.
			    */
	}	

	return 0; /* as far as we are concerned, we are happy! */
} /* jffs_scan_flash()  */


/* Insert any kind of node into the file system.  Take care of data
   insertions and deletions.  Also remove redundant information. The
   memory allocated for the `name' is regarded as "given away" in the
   caller's perspective.  */
int
jffs_insert_node(struct jffs_control *c, struct jffs_file *f,
		 const struct jffs_raw_inode *raw_inode,
		 const char *name, struct jffs_node *node)
{
	int update_name = 0;
	int insert_into_tree = 0;

	D2(printk("jffs_insert_node(): ino = %u, version = %u, "
		  "name = \"%s\", deleted = %d\n",
		  raw_inode->ino, raw_inode->version,
		  ((name && *name) ? name : ""), raw_inode->deleted));

	/* If there doesn't exist an associated jffs_file, then
	   create, initialize and insert one into the file system.  */
	if (!f && !(f = jffs_find_file(c, raw_inode->ino))) {
		if (!(f = jffs_create_file(c, raw_inode))) {
			return -ENOMEM;
		}
		jffs_insert_file_into_hash(f);
		insert_into_tree = 1;
	}
	node->ino = raw_inode->ino;
	node->version = raw_inode->version;
	node->data_size = raw_inode->dsize;
	node->fm_offset = sizeof(struct jffs_raw_inode) + raw_inode->nsize
			  + JFFS_GET_PAD_BYTES(raw_inode->nsize);
	node->name_size = raw_inode->nsize;

	/* Now insert the node at the correct position into the file's
	   version list.  */
	if (!f->version_head) {
		/* This is the first node.  */
		f->version_head = node;
		f->version_tail = node;
		node->version_prev = NULL;
		node->version_next = NULL;
		f->highest_version = node->version;
		update_name = 1;
		f->mode = raw_inode->mode;
		f->uid = raw_inode->uid;
		f->gid = raw_inode->gid;
		f->atime = raw_inode->atime;
		f->mtime = raw_inode->mtime;
		f->ctime = raw_inode->ctime;
	}
	else if ((f->highest_version < node->version)
		 || (node->version == 0)) {
		/* Insert at the end of the list.  I.e. this node is the
		   newest one so far.  */
		node->version_prev = f->version_tail;
		node->version_next = NULL;
		f->version_tail->version_next = node;
		f->version_tail = node;
		f->highest_version = node->version;
		update_name = 1;
		f->pino = raw_inode->pino;
		f->mode = raw_inode->mode;
		f->uid = raw_inode->uid;
		f->gid = raw_inode->gid;
		f->atime = raw_inode->atime;
		f->mtime = raw_inode->mtime;
		f->ctime = raw_inode->ctime;
	}
	else if (f->version_head->version > node->version) {
		/* Insert at the bottom of the list.  */
		node->version_prev = NULL;
		node->version_next = f->version_head;
		f->version_head->version_prev = node;
		f->version_head = node;
		if (!f->name) {
			update_name = 1;
		}
	}
	else {
		struct jffs_node *n;
		int newer_name = 0;
		/* Search for the insertion position starting from
		   the tail (newest node).  */
		for (n = f->version_tail; n; n = n->version_prev) {
			if (n->version < node->version) {
				node->version_prev = n;
				node->version_next = n->version_next;
				node->version_next->version_prev = node;
				n->version_next = node;
				if (!newer_name) {
					update_name = 1;
				}
				break;
			}
			if (n->name_size) {
				newer_name = 1;
			}
		}
	}

	/* Deletion is irreversible. If any 'deleted' node is ever
	   written, the file is deleted */
	if (raw_inode->deleted)
		f->deleted = raw_inode->deleted;

	/* Perhaps update the name.  */
	if (raw_inode->nsize && update_name && name && *name && (name != f->name)) {
		if (f->name) {
			kfree(f->name);
			DJM(no_name--);
		}
		if (!(f->name = (char *) kmalloc(raw_inode->nsize + 1,
						 GFP_KERNEL))) {
			return -ENOMEM;
		}
		DJM(no_name++);
		memcpy(f->name, name, raw_inode->nsize);
		f->name[raw_inode->nsize] = '\0';
		f->nsize = raw_inode->nsize;
		D3(printk("jffs_insert_node(): Updated the name of "
			  "the file to \"%s\".\n", name));
	}

	if (!c->building_fs) {
		D3(printk("jffs_insert_node(): ---------------------------"
			  "------------------------------------------- 1\n"));
		if (insert_into_tree) {
			jffs_insert_file_into_tree(f);
		}
		/* Once upon a time, we would call jffs_possibly_delete_file()
		   here. That causes an oops if someone's still got the file
		   open, so now we only do it in jffs_delete_inode()
		   -- dwmw2
		*/
		if (node->data_size || node->removed_size) {
			jffs_update_file(f, node);
		}
		jffs_remove_redundant_nodes(f);

		jffs_garbage_collect_trigger(c);

		D3(printk("jffs_insert_node(): ---------------------------"
			  "------------------------------------------- 2\n"));
	}

	return 0;
} /* jffs_insert_node()  */


/* Unlink a jffs_node from the version list it is in.  */
static inline void
jffs_unlink_node_from_version_list(struct jffs_file *f,
				   struct jffs_node *node)
{
	if (node->version_prev) {
		node->version_prev->version_next = node->version_next;
	} else {
		f->version_head = node->version_next;
	}
	if (node->version_next) {
		node->version_next->version_prev = node->version_prev;
	} else {
		f->version_tail = node->version_prev;
	}
}


/* Unlink a jffs_node from the range list it is in.  */
static inline void
jffs_unlink_node_from_range_list(struct jffs_file *f, struct jffs_node *node)
{
	if (node->range_prev) {
		node->range_prev->range_next = node->range_next;
	}
	else {
		f->range_head = node->range_next;
	}
	if (node->range_next) {
		node->range_next->range_prev = node->range_prev;
	}
	else {
		f->range_tail = node->range_prev;
	}
}


/* Function used by jffs_remove_redundant_nodes() below.  This function
   classifies what kind of information a node adds to a file.  */
static inline __u8
jffs_classify_node(struct jffs_node *node)
{
	__u8 mod_type = JFFS_MODIFY_INODE;

	if (node->name_size) {
		mod_type |= JFFS_MODIFY_NAME;
	}
	if (node->data_size || node->removed_size) {
		mod_type |= JFFS_MODIFY_DATA;
	}
	return mod_type;
}


/* Remove redundant nodes from a file.  Mark the on-flash memory
   as dirty.  */
static int
jffs_remove_redundant_nodes(struct jffs_file *f)
{
	struct jffs_node *newest_node;
	struct jffs_node *cur;
	struct jffs_node *prev;
	__u8 newest_type;
	__u8 mod_type;
	__u8 node_with_name_later = 0;

	if (!(newest_node = f->version_tail)) {
		return 0;
	}

	/* What does the `newest_node' modify?  */
	newest_type = jffs_classify_node(newest_node);
	node_with_name_later = newest_type & JFFS_MODIFY_NAME;

	D3(printk("jffs_remove_redundant_nodes(): ino: %u, name: \"%s\", "
		  "newest_type: %u\n", f->ino, (f->name ? f->name : ""),
		  newest_type));

	/* Traverse the file's nodes and determine which of them that are
	   superfluous.  Yeah, this might look very complex at first
	   glance but it is actually very simple.  */
	for (cur = newest_node->version_prev; cur; cur = prev) {
		prev = cur->version_prev;
		mod_type = jffs_classify_node(cur);
		if ((mod_type <= JFFS_MODIFY_INODE)
		    || ((newest_type & JFFS_MODIFY_NAME)
			&& (mod_type
			    <= (JFFS_MODIFY_INODE + JFFS_MODIFY_NAME)))
		    || (cur->data_size == 0 && cur->removed_size
			&& !cur->version_prev && node_with_name_later)) {
			/* Yes, this node is redundant. Remove it.  */
			D2(printk("jffs_remove_redundant_nodes(): "
				  "Removing node: ino: %u, version: %u, "
				  "mod_type: %u\n", cur->ino, cur->version,
				  mod_type));
			jffs_unlink_node_from_version_list(f, cur);
			jffs_fmfree(f->c->fmc, cur->fm, cur);
			jffs_free_node(cur);
			DJM(no_jffs_node--);
		}
		else {
			node_with_name_later |= (mod_type & JFFS_MODIFY_NAME);
		}
	}

	return 0;
}


/* Insert a file into the hash table.  */
static int
jffs_insert_file_into_hash(struct jffs_file *f)
{
	int i = f->ino % f->c->hash_len;

	D3(printk("jffs_insert_file_into_hash(): f->ino: %u\n", f->ino));

	list_add(&f->hash, &f->c->hash[i]);
	return 0;
}


/* Insert a file into the file system tree.  */
int
jffs_insert_file_into_tree(struct jffs_file *f)
{
	struct jffs_file *parent;

	D3(printk("jffs_insert_file_into_tree(): name: \"%s\"\n",
		  (f->name ? f->name : "")));

	if (!(parent = jffs_find_file(f->c, f->pino))) {
		if (f->pino == 0) {
			f->c->root = f;
			f->parent = NULL;
			f->sibling_prev = NULL;
			f->sibling_next = NULL;
			return 0;
		}
		else {
			D1(printk("jffs_insert_file_into_tree(): Found "
				  "inode with no parent and pino == %u\n",
				  f->pino));
			return -1;
		}
	}
	f->parent = parent;
	f->sibling_next = parent->children;
	if (f->sibling_next) {
		f->sibling_next->sibling_prev = f;
	}
	f->sibling_prev = NULL;
	parent->children = f;
	return 0;
}


/* Remove a file from the hash table.  */
static int
jffs_unlink_file_from_hash(struct jffs_file *f)
{
	D3(printk("jffs_unlink_file_from_hash(): f: 0x%p, "
		  "ino %u\n", f, f->ino));

	list_del(&f->hash);
	return 0;
}


/* Just remove the file from the parent's children.  Don't free
   any memory.  */
int
jffs_unlink_file_from_tree(struct jffs_file *f)
{
	D3(printk("jffs_unlink_file_from_tree(): ino: %d, pino: %d, name: "
		  "\"%s\"\n", f->ino, f->pino, (f->name ? f->name : "")));

	if (f->sibling_prev) {
		f->sibling_prev->sibling_next = f->sibling_next;
	}
	else if (f->parent) {
	        D3(printk("f->parent=%p\n", f->parent));
		f->parent->children = f->sibling_next;
	}
	if (f->sibling_next) {
		f->sibling_next->sibling_prev = f->sibling_prev;
	}
	return 0;
}


/* Find a file with its inode number.  */
struct jffs_file *
jffs_find_file(struct jffs_control *c, __u32 ino)
{
	struct jffs_file *f;
	int i = ino % c->hash_len;

	D3(printk("jffs_find_file(): ino: %u\n", ino));

	list_for_each_entry(f, &c->hash[i], hash) {
		if (ino != f->ino)
			continue;
		D3(printk("jffs_find_file(): Found file with ino "
			       "%u. (name: \"%s\")\n",
			       ino, (f->name ? f->name : ""));
		);
		return f;
	}
	D3(printk("jffs_find_file(): Didn't find file "
			 "with ino %u.\n", ino);
	);
	return NULL;
}


/* Find a file in a directory.  We are comparing the names.  */
struct jffs_file *
jffs_find_child(struct jffs_file *dir, const char *name, int len)
{
	struct jffs_file *f;

	D3(printk("jffs_find_child()\n"));

	for (f = dir->children; f; f = f->sibling_next) {
		if (!f->deleted && f->name
		    && !strncmp(f->name, name, len)
		    && f->name[len] == '\0') {
			break;
		}
	}

	D3(if (f) {
		printk("jffs_find_child(): Found \"%s\".\n", f->name);
	}
	else {
		char *copy = (char *) kmalloc(len + 1, GFP_KERNEL);
		if (copy) {
			memcpy(copy, name, len);
			copy[len] = '\0';
		}
		printk("jffs_find_child(): Didn't find the file \"%s\".\n",
		       (copy ? copy : ""));
		kfree(copy);
	});

	return f;
}


/* Write a raw inode that takes up a certain amount of space in the flash
   memory.  At the end of the flash device, there is often space that is
   impossible to use.  At these times we want to mark this space as not
   used.  In the cases when the amount of space is greater or equal than
   a struct jffs_raw_inode, we write a "dummy node" that takes up this
   space.  The space after the raw inode, if it exists, is left as it is.
   Since this space after the raw inode contains JFFS_EMPTY_BITMASK bytes,
   we can compute the checksum of it; we don't have to manipulate it any
   further.

   If the space left on the device is less than the size of a struct
   jffs_raw_inode, this space is filled with JFFS_DIRTY_BITMASK bytes.
   No raw inode is written this time.  */
static int
jffs_write_dummy_node(struct jffs_control *c, struct jffs_fm *dirty_fm)
{
	struct jffs_fmcontrol *fmc = c->fmc;
	int err;

	D1(printk("jffs_write_dummy_node(): dirty_fm->offset = 0x%08x, "
		  "dirty_fm->size = %u\n",
		  dirty_fm->offset, dirty_fm->size));

	if (dirty_fm->size >= sizeof(struct jffs_raw_inode)) {
		struct jffs_raw_inode raw_inode;
		memset(&raw_inode, 0, sizeof(struct jffs_raw_inode));
		raw_inode.magic = JFFS_MAGIC_BITMASK;
		raw_inode.dsize = dirty_fm->size
				  - sizeof(struct jffs_raw_inode);
		raw_inode.dchksum = raw_inode.dsize * 0xff;
		raw_inode.chksum
		= jffs_checksum(&raw_inode, sizeof(struct jffs_raw_inode));

		if ((err = flash_safe_write(fmc->mtd,
					    dirty_fm->offset,
					    (u_char *)&raw_inode,
					    sizeof(struct jffs_raw_inode)))
		    < 0) {
			printk(KERN_ERR "JFFS: jffs_write_dummy_node: "
			       "flash_safe_write failed!\n");
			return err;
		}
	}
	else {
		flash_safe_acquire(fmc->mtd);
		flash_memset(fmc->mtd, dirty_fm->offset, 0, dirty_fm->size);
		flash_safe_release(fmc->mtd);
	}

	D3(printk("jffs_write_dummy_node(): Leaving...\n"));
	return 0;
}


/* Write a raw inode, possibly its name and possibly some data.  */
int
jffs_write_node(struct jffs_control *c, struct jffs_node *node,
		struct jffs_raw_inode *raw_inode,
		const char *name, const unsigned char *data,
		int recoverable,
		struct jffs_file *f)
{
	struct jffs_fmcontrol *fmc = c->fmc;
	struct jffs_fm *fm;
	struct kvec node_iovec[4];
	unsigned long iovec_cnt;

	__u32 pos;
	int err;
	__u32 slack = 0;

	__u32 total_name_size = raw_inode->nsize
				+ JFFS_GET_PAD_BYTES(raw_inode->nsize);
	__u32 total_data_size = raw_inode->dsize
				+ JFFS_GET_PAD_BYTES(raw_inode->dsize);
	__u32 total_size = sizeof(struct jffs_raw_inode)
			   + total_name_size + total_data_size;
	
	/* If this node isn't something that will eventually let
	   GC free even more space, then don't allow it unless
	   there's at least max_chunk_size space still available
	*/
	if (!recoverable)
		slack = fmc->max_chunk_size;
		

	/* Fire the retrorockets and shoot the fruiton torpedoes, sir!  */

	ASSERT(if (!node) {
		printk("jffs_write_node(): node == NULL\n");
		return -EINVAL;
	});
	ASSERT(if (raw_inode && raw_inode->nsize && !name) {
		printk("*** jffs_write_node(): nsize = %u but name == NULL\n",
		       raw_inode->nsize);
		return -EINVAL;
	});

	D1(printk("jffs_write_node(): filename = \"%s\", ino = %u, "
		  "total_size = %u\n",
		  (name ? name : ""), raw_inode->ino,
		  total_size));

	jffs_fm_write_lock(fmc);

retry:
	fm = NULL;
	err = 0;
	while (!fm) {

		/* Deadlocks suck. */
		while(fmc->free_size < fmc->min_free_size + total_size + slack) {
			jffs_fm_write_unlock(fmc);
			if (!JFFS_ENOUGH_SPACE(c, total_size + slack))
				return -ENOSPC;
			jffs_fm_write_lock(fmc);
		}

		/* First try to allocate some flash memory.  */
		err = jffs_fmalloc(fmc, total_size, node, &fm);
		
		if (err == -ENOSPC) {
			/* Just out of space. GC and try again */
			if (fmc->dirty_size < fmc->sector_size) {
				D(printk("jffs_write_node(): jffs_fmalloc(0x%p, %u) "
					 "failed, no dirty space to GC\n", fmc,
					 total_size));
				return err;
			}
			
			D1(printk(KERN_INFO "jffs_write_node(): Calling jffs_garbage_collect_now()\n"));
			jffs_fm_write_unlock(fmc);
			if ((err = jffs_garbage_collect_now(c))) {
				D(printk("jffs_write_node(): jffs_garbage_collect_now() failed\n"));
				return err;
			}
			jffs_fm_write_lock(fmc);
			continue;
		} 

		if (err < 0) {
			jffs_fm_write_unlock(fmc);

			D(printk("jffs_write_node(): jffs_fmalloc(0x%p, %u) "
				 "failed!\n", fmc, total_size));
			return err;
		}

		if (!fm->nodes) {
			/* The jffs_fm struct that we got is not good enough.
			   Make that space dirty and try again  */
			if ((err = jffs_write_dummy_node(c, fm)) < 0) {
				kfree(fm);
				DJM(no_jffs_fm--);
				jffs_fm_write_unlock(fmc);
				D(printk("jffs_write_node(): "
					 "jffs_write_dummy_node(): Failed!\n"));
				return err;
			}
			fm = NULL;
		}
	} /* while(!fm) */
	node->fm = fm;

	ASSERT(if (fm->nodes == 0) {
		printk(KERN_ERR "jffs_write_node(): fm->nodes == 0\n");
	});

	pos = node->fm->offset;

	/* Increment the version number here. We can't let the caller
	   set it beforehand, because we might have had to do GC on a node
	   of this file - and we'd end up reusing version numbers.
	*/
	if (f) {
		raw_inode->version = f->highest_version + 1;
		D1(printk (KERN_NOTICE "jffs_write_node(): setting version of %s to %d\n", f->name, raw_inode->version));

		/* if the file was deleted, set the deleted bit in the raw inode */
		if (f->deleted)
			raw_inode->deleted = 1;
	}

	/* Compute the checksum for the data and name chunks.  */
	raw_inode->dchksum = jffs_checksum(data, raw_inode->dsize);
	raw_inode->nchksum = jffs_checksum(name, raw_inode->nsize);

	/* The checksum is calculated without the chksum and accurate
	   fields so set them to zero first.  */
	raw_inode->accurate = 0;
	raw_inode->chksum = 0;
	raw_inode->chksum = jffs_checksum(raw_inode,
					  sizeof(struct jffs_raw_inode));
	raw_inode->accurate = 0xff;

	D3(printk("jffs_write_node(): About to write this raw inode to the "
		  "flash at pos 0x%lx:\n", (long)pos));
	D3(jffs_print_raw_inode(raw_inode));

	/* The actual raw JFFS node */
	node_iovec[0].iov_base = (void *) raw_inode;
	node_iovec[0].iov_len = (size_t) sizeof(struct jffs_raw_inode);
	iovec_cnt = 1;

	/* Get name and size if there is one */
	if (raw_inode->nsize) {
		node_iovec[iovec_cnt].iov_base = (void *) name;
		node_iovec[iovec_cnt].iov_len = (size_t) raw_inode->nsize;
		iovec_cnt++;

		if (JFFS_GET_PAD_BYTES(raw_inode->nsize)) {
			static unsigned char allff[3]={255,255,255};
			/* Add some extra padding if necessary */
			node_iovec[iovec_cnt].iov_base = allff;
			node_iovec[iovec_cnt].iov_len =
				JFFS_GET_PAD_BYTES(raw_inode->nsize);
			iovec_cnt++;
		}
	}

	/* Get data and size if there is any */
	if (raw_inode->dsize) {
		node_iovec[iovec_cnt].iov_base = (void *) data;
		node_iovec[iovec_cnt].iov_len = (size_t) raw_inode->dsize;
		iovec_cnt++;
		/* No need to pad this because we're not actually putting
		   anything after it.
		*/
	}

	if ((err = flash_safe_writev(fmc->mtd, node_iovec, iovec_cnt,
				    pos)) < 0) {
		jffs_fmfree_partly(fmc, fm, 0);
		jffs_fm_write_unlock(fmc);
		printk(KERN_ERR "JFFS: jffs_write_node: Failed to write, "
		       "requested %i, wrote %i\n", total_size, err);
		goto retry;
	}
	if (raw_inode->deleted)
		f->deleted = 1;

	jffs_fm_write_unlock(fmc);
	D3(printk("jffs_write_node(): Leaving...\n"));
	return raw_inode->dsize;
} /* jffs_write_node()  */


/* Read data from the node and write it to the buffer.  'node_offset'
   is how much we have read from this particular node before and which
   shouldn't be read again.  'max_size' is how much space there is in
   the buffer.  */
static int
jffs_get_node_data(struct jffs_file *f, struct jffs_node *node, 
		   unsigned char *buf,__u32 node_offset, __u32 max_size)
{
	struct jffs_fmcontrol *fmc = f->c->fmc;
	__u32 pos = node->fm->offset + node->fm_offset + node_offset;
	__u32 avail = node->data_size - node_offset;
	__u32 r;

	D2(printk("  jffs_get_node_data(): file: \"%s\", ino: %u, "
		  "version: %u, node_offset: %u\n",
		  f->name, node->ino, node->version, node_offset));

	r = min(avail, max_size);
	D3(printk(KERN_NOTICE "jffs_get_node_data\n"));
	flash_safe_read(fmc->mtd, pos, buf, r);

	D3(printk("  jffs_get_node_data(): Read %u byte%s.\n",
		  r, (r == 1 ? "" : "s")));

	return r;
}


/* Read data from the file's nodes.  Write the data to the buffer
   'buf'.  'read_offset' tells how much data we should skip.  */
int
jffs_read_data(struct jffs_file *f, unsigned char *buf, __u32 read_offset,
	       __u32 size)
{
	struct jffs_node *node;
	__u32 read_data = 0; /* Total amount of read data.  */
	__u32 node_offset = 0;
	__u32 pos = 0; /* Number of bytes traversed.  */

	D2(printk("jffs_read_data(): file = \"%s\", read_offset = %d, "
		  "size = %u\n",
		  (f->name ? f->name : ""), read_offset, size));

	if (read_offset >= f->size) {
		D(printk("  f->size: %d\n", f->size));
		return 0;
	}

	/* First find the node to read data from.  */
	node = f->range_head;
	while (pos <= read_offset) {
		node_offset = read_offset - pos;
		if (node_offset >= node->data_size) {
			pos += node->data_size;
			node = node->range_next;
		}
		else {
			break;
		}
	}

	/* "Cats are living proof that not everything in nature
	   has to be useful."
	   - Garrison Keilor ('97)  */

	/* Fill the buffer.  */
	while (node && (read_data < size)) {
		int r;
		if (!node->fm) {
			/* This node does not refer to real data.  */
			r = min(size - read_data,
				     node->data_size - node_offset);
			memset(&buf[read_data], 0, r);
		}
		else if ((r = jffs_get_node_data(f, node, &buf[read_data],
						 node_offset,
						 size - read_data)) < 0) {
			return r;
		}
		read_data += r;
		node_offset = 0;
		node = node->range_next;
	}
	D3(printk("  jffs_read_data(): Read %u bytes.\n", read_data));
	return read_data;
}


/* Used for traversing all nodes in the hash table.  */
int
jffs_foreach_file(struct jffs_control *c, int (*func)(struct jffs_file *))
{
	int pos;
	int r;
	int result = 0;

	for (pos = 0; pos < c->hash_len; pos++) {
		struct jffs_file *f, *next;

		/* We must do _safe, because 'func' might remove the
		   current file 'f' from the list.  */
		list_for_each_entry_safe(f, next, &c->hash[pos], hash) {
			r = func(f);
			if (r < 0)
				return r;
			result += r;
		}
	}

	return result;
}


/* Free all nodes associated with a file.  */
static int
jffs_free_node_list(struct jffs_file *f)
{
	struct jffs_node *node;
	struct jffs_node *p;

	D3(printk("jffs_free_node_list(): f #%u, \"%s\"\n",
		  f->ino, (f->name ? f->name : "")));
	node = f->version_head;
	while (node) {
		p = node;
		node = node->version_next;
		jffs_free_node(p);
		DJM(no_jffs_node--);
	}
	return 0;
}


/* Free a file and its name.  */
static int
jffs_free_file(struct jffs_file *f)
{
	D3(printk("jffs_free_file: f #%u, \"%s\"\n",
		  f->ino, (f->name ? f->name : "")));

	if (f->name) {
		kfree(f->name);
		DJM(no_name--);
	}
	kfree(f);
	no_jffs_file--;
	return 0;
}

static long
jffs_get_file_count(void)
{
	return no_jffs_file;
}

/* See if a file is deleted. If so, mark that file's nodes as obsolete.  */
int
jffs_possibly_delete_file(struct jffs_file *f)
{
	struct jffs_node *n;

	D3(printk("jffs_possibly_delete_file(): ino: %u\n",
		  f->ino));

	ASSERT(if (!f) {
		printk(KERN_ERR "jffs_possibly_delete_file(): f == NULL\n");
		return -1;
	});

	if (f->deleted) {
		/* First try to remove all older versions.  Commence with
		   the oldest node.  */
		for (n = f->version_head; n; n = n->version_next) {
			if (!n->fm) {
				continue;
			}
			if (jffs_fmfree(f->c->fmc, n->fm, n) < 0) {
				break;
			}
		}
		/* Unlink the file from the filesystem.  */
		if (!f->c->building_fs) {
			jffs_unlink_file_from_tree(f);
		}
		jffs_unlink_file_from_hash(f);
		jffs_free_node_list(f);
		jffs_free_file(f);
	}
	return 0;
}


/* Used in conjunction with jffs_foreach_file() to count the number
   of files in the file system.  */
int
jffs_file_count(struct jffs_file *f)
{
	return 1;
}


/* Build up a file's range list from scratch by going through the
   version list.  */
static int
jffs_build_file(struct jffs_file *f)
{
	struct jffs_node *n;

	D3(printk("jffs_build_file(): ino: %u, name: \"%s\"\n",
		  f->ino, (f->name ? f->name : "")));

	for (n = f->version_head; n; n = n->version_next) {
		jffs_update_file(f, n);
	}
	return 0;
}


/* Remove an amount of data from a file. If this amount of data is
   zero, that could mean that a node should be split in two parts.
   We remove or change the appropriate nodes in the lists.

   Starting offset of area to be removed is node->data_offset,
   and the length of the area is in node->removed_size.   */
static int
jffs_delete_data(struct jffs_file *f, struct jffs_node *node)
{
	struct jffs_node *n;
	__u32 offset = node->data_offset;
	__u32 remove_size = node->removed_size;

	D3(printk("jffs_delete_data(): offset = %u, remove_size = %u\n",
		  offset, remove_size));

	if (remove_size == 0
	    && f->range_tail
	    && f->range_tail->data_offset + f->range_tail->data_size
	       == offset) {
		/* A simple append; nothing to remove or no node to split.  */
		return 0;
	}

	/* Find the node where we should begin the removal.  */
	for (n = f->range_head; n; n = n->range_next) {
		if (n->data_offset + n->data_size > offset) {
			break;
		}
	}
	if (!n) {
		/* If there's no data in the file there's no data to
		   remove either.  */
		return 0;
	}

	if (n->data_offset > offset) {
		/* XXX: Not implemented yet.  */
		printk(KERN_WARNING "JFFS: An unexpected situation "
		       "occurred in jffs_delete_data.\n");
	}
	else if (n->data_offset < offset) {
		/* See if the node has to be split into two parts.  */
		if (n->data_offset + n->data_size > offset + remove_size) {
			/* Do the split.  */
			struct jffs_node *new_node;
			D3(printk("jffs_delete_data(): Split node with "
				  "version number %u.\n", n->version));

			if (!(new_node = jffs_alloc_node())) {
				D(printk("jffs_delete_data(): -ENOMEM\n"));
				return -ENOMEM;
			}
			DJM(no_jffs_node++);

			new_node->ino = n->ino;
			new_node->version = n->version;
			new_node->data_offset = offset;
			new_node->data_size = n->data_size - (remove_size + (offset - n->data_offset));
			new_node->fm_offset = n->fm_offset + (remove_size + (offset - n->data_offset));
			new_node->name_size = n->name_size;
			new_node->fm = n->fm;
			new_node->version_prev = n;
			new_node->version_next = n->version_next;
			if (new_node->version_next) {
				new_node->version_next->version_prev
				= new_node;
			}
			else {
				f->version_tail = new_node;
			}
			n->version_next = new_node;
			new_node->range_prev = n;
			new_node->range_next = n->range_next;
			if (new_node->range_next) {
				new_node->range_next->range_prev = new_node;
			}
			else {
				f->range_tail = new_node;
			}
			/* A very interesting can of worms.  */
			n->range_next = new_node;
			n->data_size = offset - n->data_offset;
			if (new_node->fm)
				jffs_add_node(new_node);
			else {
				D1(printk(KERN_WARNING "jffs_delete_data(): Splitting an empty node (file hold).\n!"));
				D1(printk(KERN_WARNING "FIXME: Did dwmw2 do the right thing here?\n"));
			}
			n = new_node->range_next;
			remove_size = 0;
		}
		else {
			/* No.  No need to split the node.  Just remove
			   the end of the node.  */
			int r = min(n->data_offset + n->data_size
					 - offset, remove_size);
			n->data_size -= r;
			remove_size -= r;
			n = n->range_next;
		}
	}

	/* Remove as many nodes as necessary.  */
	while (n && remove_size) {
		if (n->data_size <= remove_size) {
			struct jffs_node *p = n;
			remove_size -= n->data_size;
			n = n->range_next;
			D3(printk("jffs_delete_data(): Removing node: "
				  "ino: %u, version: %u%s\n",
				  p->ino, p->version,
				  (p->fm ? "" : " (virtual)")));
			if (p->fm) {
				jffs_fmfree(f->c->fmc, p->fm, p);
			}
			jffs_unlink_node_from_range_list(f, p);
			jffs_unlink_node_from_version_list(f, p);
			jffs_free_node(p);
			DJM(no_jffs_node--);
		}
		else {
			n->data_size -= remove_size;
			n->fm_offset += remove_size;
			n->data_offset -= (node->removed_size - remove_size);
			n = n->range_next;
			break;
		}
	}

	/* Adjust the following nodes' information about offsets etc.  */
	while (n && node->removed_size) {
		n->data_offset -= node->removed_size;
		n = n->range_next;
	}

	if (node->removed_size > (f->size - node->data_offset)) {
		/* It's possible that the removed_size is in fact
		 * greater than the amount of data we actually thought
		 * were present in the first place - some of the nodes 
		 * which this node originally obsoleted may already have
		 * been deleted from the flash by subsequent garbage 
		 * collection.
		 *
		 * If this is the case, don't let f->size go negative.
		 * Bad things would happen :)
		 */
		f->size = node->data_offset;
	} else {
		f->size -= node->removed_size;
	}
	D3(printk("jffs_delete_data(): f->size = %d\n", f->size));
	return 0;
} /* jffs_delete_data()  */


/* Insert some data into a file.  Prior to the call to this function,
   jffs_delete_data should be called.  */
static int
jffs_insert_data(struct jffs_file *f, struct jffs_node *node)
{
	D3(printk("jffs_insert_data(): node->data_offset = %u, "
		  "node->data_size = %u, f->size = %u\n",
		  node->data_offset, node->data_size, f->size));

	/* Find the position where we should insert data.  */
	retry:
	if (node->data_offset == f->size) {
		/* A simple append.  This is the most common operation.  */
		node->range_next = NULL;
		node->range_prev = f->range_tail;
		if (node->range_prev) {
			node->range_prev->range_next = node;
		}
		f->range_tail = node;
		f->size += node->data_size;
		if (!f->range_head) {
			f->range_head = node;
		}
	}
	else if (node->data_offset < f->size) {
		/* Trying to insert data into the middle of the file.  This
		   means no problem because jffs_delete_data() has already
		   prepared the range list for us.  */
		struct jffs_node *n;

		/* Find the correct place for the insertion and then insert
		   the node.  */
		for (n = f->range_head; n; n = n->range_next) {
			D2(printk("Cool stuff's happening!\n"));

			if (n->data_offset == node->data_offset) {
				node->range_prev = n->range_prev;
				if (node->range_prev) {
					node->range_prev->range_next = node;
				}
				else {
					f->range_head = node;
				}
				node->range_next = n;
				n->range_prev = node;
				break;
			}
			ASSERT(else if (n->data_offset + n->data_size >
					node->data_offset) {
				printk(KERN_ERR "jffs_insert_data(): "
				       "Couldn't find a place to insert "
				       "the data!\n");
				return -1;
			});
		}

		/* Adjust later nodes' offsets etc.  */
		n = node->range_next;
		while (n) {
			n->data_offset += node->data_size;
			n = n->range_next;
		}
		f->size += node->data_size;
	}
	else if (node->data_offset > f->size) {
		/* Okay.  This is tricky.  This means that we want to insert
		   data at a place that is beyond the limits of the file as
		   it is constructed right now.  This is actually a common
		   event that for instance could occur during the mounting
		   of the file system if a large file have been truncated,
		   rewritten and then only partially garbage collected.  */

		struct jffs_node *n;

		/* We need a place holder for the data that is missing in
		   front of this insertion.  This "virtual node" will not
		   be associated with any space on the flash device.  */
		struct jffs_node *virtual_node;
		if (!(virtual_node = jffs_alloc_node())) {
			return -ENOMEM;
		}

		D(printk("jffs_insert_data: Inserting a virtual node.\n"));
		D(printk("  node->data_offset = %u\n", node->data_offset));
		D(printk("  f->size = %u\n", f->size));

		virtual_node->ino = node->ino;
		virtual_node->version = node->version;
		virtual_node->removed_size = 0;
		virtual_node->fm_offset = 0;
		virtual_node->name_size = 0;
		virtual_node->fm = NULL; /* This is a virtual data holder.  */
		virtual_node->version_prev = NULL;
		virtual_node->version_next = NULL;
		virtual_node->range_next = NULL;

		/* Are there any data at all in the file yet?  */
		if (f->range_head) {
			virtual_node->data_offset
			= f->range_tail->data_offset
			  + f->range_tail->data_size;
			virtual_node->data_size
			= node->data_offset - virtual_node->data_offset;
			virtual_node->range_prev = f->range_tail;
			f->range_tail->range_next = virtual_node;
		}
		else {
			virtual_node->data_offset = 0;
			virtual_node->data_size = node->data_offset;
			virtual_node->range_prev = NULL;
			f->range_head = virtual_node;
		}

		f->range_tail = virtual_node;
		f->size += virtual_node->data_size;

		/* Insert this virtual node in the version list as well.  */
		for (n = f->version_head; n ; n = n->version_next) {
			if (n->version == virtual_node->version) {
				virtual_node->version_prev = n->version_prev;
				n->version_prev = virtual_node;
				if (virtual_node->version_prev) {
					virtual_node->version_prev
					->version_next = virtual_node;
				}
				else {
					f->version_head = virtual_node;
				}
				virtual_node->version_next = n;
				break;
			}
		}

		D(jffs_print_node(virtual_node));

		/* Make a new try to insert the node.  */
		goto retry;
	}

	D3(printk("jffs_insert_data(): f->size = %d\n", f->size));
	return 0;
}


/* A new node (with data) has been added to the file and now the range
   list has to be modified.  */
static int
jffs_update_file(struct jffs_file *f, struct jffs_node *node)
{
	int err;

	D3(printk("jffs_update_file(): ino: %u, version: %u\n",
		  f->ino, node->version));

	if (node->data_size == 0) {
		if (node->removed_size == 0) {
			/* data_offset == X  */
			/* data_size == 0  */
			/* remove_size == 0  */
		}
		else {
			/* data_offset == X  */
			/* data_size == 0  */
			/* remove_size != 0  */
			if ((err = jffs_delete_data(f, node)) < 0) {
				return err;
			}
		}
	}
	else {
		/* data_offset == X  */
		/* data_size != 0  */
		/* remove_size == Y  */
		if ((err = jffs_delete_data(f, node)) < 0) {
			return err;
		}
		if ((err = jffs_insert_data(f, node)) < 0) {
			return err;
		}
	}
	return 0;
}

/* Print the contents of a file.  */
#if 0
int
jffs_print_file(struct jffs_file *f)
{
	D(int i);
	D(printk("jffs_file: 0x%p\n", f));
	D(printk("{\n"));
	D(printk("        0x%08x, /* ino  */\n", f->ino));
	D(printk("        0x%08x, /* pino  */\n", f->pino));
	D(printk("        0x%08x, /* mode  */\n", f->mode));
	D(printk("        0x%04x,     /* uid  */\n", f->uid));
	D(printk("        0x%04x,     /* gid  */\n", f->gid));
	D(printk("        0x%08x, /* atime  */\n", f->atime));
	D(printk("        0x%08x, /* mtime  */\n", f->mtime));
	D(printk("        0x%08x, /* ctime  */\n", f->ctime));
	D(printk("        0x%02x,       /* nsize  */\n", f->nsize));
	D(printk("        0x%02x,       /* nlink  */\n", f->nlink));
	D(printk("        0x%02x,       /* deleted  */\n", f->deleted));
	D(printk("        \"%s\", ", (f->name ? f->name : "")));
	D(for (i = strlen(f->name ? f->name : ""); i < 8; ++i) {
		printk(" ");
	});
	D(printk("/* name  */\n"));
	D(printk("        0x%08x, /* size  */\n", f->size));
	D(printk("        0x%08x, /* highest_version  */\n",
		 f->highest_version));
	D(printk("        0x%p, /* c  */\n", f->c));
	D(printk("        0x%p, /* parent  */\n", f->parent));
	D(printk("        0x%p, /* children  */\n", f->children));
	D(printk("        0x%p, /* sibling_prev  */\n", f->sibling_prev));
	D(printk("        0x%p, /* sibling_next  */\n", f->sibling_next));
	D(printk("        0x%p, /* hash_prev  */\n", f->hash.prev));
	D(printk("        0x%p, /* hash_next  */\n", f->hash.next));
	D(printk("        0x%p, /* range_head  */\n", f->range_head));
	D(printk("        0x%p, /* range_tail  */\n", f->range_tail));
	D(printk("        0x%p, /* version_head  */\n", f->version_head));
	D(printk("        0x%p, /* version_tail  */\n", f->version_tail));
	D(printk("}\n"));
	return 0;
}
#endif  /*  0  */

void
jffs_print_hash_table(struct jffs_control *c)
{
	int i;

	printk("JFFS: Dumping the file system's hash table...\n");
	for (i = 0; i < c->hash_len; i++) {
		struct jffs_file *f;
		list_for_each_entry(f, &c->hash[i], hash) {
			printk("*** c->hash[%u]: \"%s\" "
			       "(ino: %u, pino: %u)\n",
			       i, (f->name ? f->name : ""),
			       f->ino, f->pino);
		}
	}
}


void
jffs_print_tree(struct jffs_file *first_file, int indent)
{
	struct jffs_file *f;
	char *space;
	int dir;

	if (!first_file) {
		return;
	}

	if (!(space = (char *) kmalloc(indent + 1, GFP_KERNEL))) {
		printk("jffs_print_tree(): Out of memory!\n");
		return;
	}

	memset(space, ' ', indent);
	space[indent] = '\0';

	for (f = first_file; f; f = f->sibling_next) {
		dir = S_ISDIR(f->mode);
		printk("%s%s%s (ino: %u, highest_version: %u, size: %u)\n",
		       space, (f->name ? f->name : ""), (dir ? "/" : ""),
		       f->ino, f->highest_version, f->size);
		if (dir) {
			jffs_print_tree(f->children, indent + 2);
		}
	}

	kfree(space);
}


#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
void
jffs_print_memory_allocation_statistics(void)
{
	static long printout;
	printk("________ Memory printout #%ld ________\n", ++printout);
	printk("no_jffs_file = %ld\n", no_jffs_file);
	printk("no_jffs_node = %ld\n", no_jffs_node);
	printk("no_jffs_control = %ld\n", no_jffs_control);
	printk("no_jffs_raw_inode = %ld\n", no_jffs_raw_inode);
	printk("no_jffs_node_ref = %ld\n", no_jffs_node_ref);
	printk("no_jffs_fm = %ld\n", no_jffs_fm);
	printk("no_jffs_fmcontrol = %ld\n", no_jffs_fmcontrol);
	printk("no_hash = %ld\n", no_hash);
	printk("no_name = %ld\n", no_name);
	printk("\n");
}
#endif


/* Rewrite `size' bytes, and begin at `node'.  */
static int
jffs_rewrite_data(struct jffs_file *f, struct jffs_node *node, __u32 size)
{
	struct jffs_control *c = f->c;
	struct jffs_fmcontrol *fmc = c->fmc;
	struct jffs_raw_inode raw_inode;
	struct jffs_node *new_node;
	struct jffs_fm *fm;
	__u32 pos;
	__u32 pos_dchksum;
	__u32 total_name_size;
	__u32 total_data_size;
	__u32 total_size;
	int err;

	D1(printk("***jffs_rewrite_data(): node: %u, name: \"%s\", size: %u\n",
		  f->ino, (f->name ? f->name : "(null)"), size));

	/* Create and initialize the new node.  */
	if (!(new_node = jffs_alloc_node())) {
		D(printk("jffs_rewrite_data(): "
			 "Failed to allocate node.\n"));
		return -ENOMEM;
	}
	DJM(no_jffs_node++);
	new_node->data_offset = node->data_offset;
	new_node->removed_size = size;
	total_name_size = JFFS_PAD(f->nsize);
	total_data_size = JFFS_PAD(size);
	total_size = sizeof(struct jffs_raw_inode)
		     + total_name_size + total_data_size;
	new_node->fm_offset = sizeof(struct jffs_raw_inode)
			      + total_name_size;

retry:
	jffs_fm_write_lock(fmc);
	err = 0;

	if ((err = jffs_fmalloc(fmc, total_size, new_node, &fm)) < 0) {
		DJM(no_jffs_node--);
		jffs_fm_write_unlock(fmc);
		D(printk("jffs_rewrite_data(): Failed to allocate fm.\n"));
		jffs_free_node(new_node);
		return err;
	}
	else if (!fm->nodes) {
		/* The jffs_fm struct that we got is not big enough.  */
		/* This should never happen, because we deal with this case
		   in jffs_garbage_collect_next().*/
		printk(KERN_WARNING "jffs_rewrite_data(): Allocated node is too small (%d bytes of %d)\n", fm->size, total_size);
		if ((err = jffs_write_dummy_node(c, fm)) < 0) {
			D(printk("jffs_rewrite_data(): "
				 "jffs_write_dummy_node() Failed!\n"));
		} else {
			err = -ENOSPC;
		}
		DJM(no_jffs_fm--);
		jffs_fm_write_unlock(fmc);
		kfree(fm);
		
		return err;
	}
	new_node->fm = fm;

	/* Initialize the raw inode.  */
	raw_inode.magic = JFFS_MAGIC_BITMASK;
	raw_inode.ino = f->ino;
	raw_inode.pino = f->pino;
	raw_inode.version = f->highest_version + 1;
	raw_inode.mode = f->mode;
	raw_inode.uid = f->uid;
	raw_inode.gid = f->gid;
	raw_inode.atime = f->atime;
	raw_inode.mtime = f->mtime;
	raw_inode.ctime = f->ctime;
	raw_inode.offset = node->data_offset;
	raw_inode.dsize = size;
	raw_inode.rsize = size;
	raw_inode.nsize = f->nsize;
	raw_inode.nlink = f->nlink;
	raw_inode.spare = 0;
	raw_inode.rename = 0;
	raw_inode.deleted = f->deleted;
	raw_inode.accurate = 0xff;
	raw_inode.dchksum = 0;
	raw_inode.nchksum = 0;

	pos = new_node->fm->offset;
	pos_dchksum = pos +JFFS_RAW_INODE_DCHKSUM_OFFSET;

	D3(printk("jffs_rewrite_data(): Writing this raw inode "
		  "to pos 0x%ul.\n", pos));
	D3(jffs_print_raw_inode(&raw_inode));

	if ((err = flash_safe_write(fmc->mtd, pos,
				    (u_char *) &raw_inode,
				    sizeof(struct jffs_raw_inode)
				    - sizeof(__u32)
				    - sizeof(__u16) - sizeof(__u16))) < 0) {
		jffs_fmfree_partly(fmc, fm,
				   total_name_size + total_data_size);
		jffs_fm_write_unlock(fmc);
		printk(KERN_ERR "JFFS: jffs_rewrite_data: Write error during "
			"rewrite. (raw inode)\n");
		printk(KERN_ERR "JFFS: jffs_rewrite_data: Now retrying "
			"rewrite. (raw inode)\n");
		goto retry;
	}
	pos += sizeof(struct jffs_raw_inode);

	/* Write the name to the flash memory.  */
	if (f->nsize) {
		D3(printk("jffs_rewrite_data(): Writing name \"%s\" to "
			  "pos 0x%ul.\n", f->name, (unsigned int) pos));
		if ((err = flash_safe_write(fmc->mtd, pos,
					    (u_char *)f->name,
					    f->nsize)) < 0) {
			jffs_fmfree_partly(fmc, fm, total_data_size);
			jffs_fm_write_unlock(fmc);
			printk(KERN_ERR "JFFS: jffs_rewrite_data: Write "
				"error during rewrite. (name)\n");
			printk(KERN_ERR "JFFS: jffs_rewrite_data: Now retrying "
				"rewrite. (name)\n");
			goto retry;
		}
		pos += total_name_size;
		raw_inode.nchksum = jffs_checksum(f->name, f->nsize);
	}

	/* Write the data.  */
	if (size) {
		int r;
		unsigned char *page;
		__u32 offset = node->data_offset;

		if (!(page = (unsigned char *)__get_free_page(GFP_KERNEL))) {
			jffs_fmfree_partly(fmc, fm, 0);
			return -1;
		}

		while (size) {
			__u32 s = min(size, (__u32)PAGE_SIZE);
			if ((r = jffs_read_data(f, (char *)page,
						offset, s)) < s) {
				free_page((unsigned long)page);
				jffs_fmfree_partly(fmc, fm, 0);
				jffs_fm_write_unlock(fmc);
				printk(KERN_ERR "JFFS: jffs_rewrite_data: "
					 "jffs_read_data() "
					 "failed! (r = %d)\n", r);
				return -1;
			}
			if ((err = flash_safe_write(fmc->mtd,
						    pos, page, r)) < 0) {
				free_page((unsigned long)page);
				jffs_fmfree_partly(fmc, fm, 0);
				jffs_fm_write_unlock(fmc);
				printk(KERN_ERR "JFFS: jffs_rewrite_data: "
				       "Write error during rewrite. "
				       "(data)\n");
				goto retry;
			}
			pos += r;
			size -= r;
			offset += r;
			raw_inode.dchksum += jffs_checksum(page, r);
		}

	        free_page((unsigned long)page);
	}

	raw_inode.accurate = 0;
	raw_inode.chksum = jffs_checksum(&raw_inode,
					 sizeof(struct jffs_raw_inode)
					 - sizeof(__u16));

	/* Add the checksum.  */
	if ((err
	     = flash_safe_write(fmc->mtd, pos_dchksum,
				&((u_char *)
				&raw_inode)[JFFS_RAW_INODE_DCHKSUM_OFFSET],
				sizeof(__u32) + sizeof(__u16)
				+ sizeof(__u16))) < 0) {
		jffs_fmfree_partly(fmc, fm, 0);
		jffs_fm_write_unlock(fmc);
		printk(KERN_ERR "JFFS: jffs_rewrite_data: Write error during "
		       "rewrite. (checksum)\n");
		goto retry;
	}

	/* Now make the file system aware of the newly written node.  */
	jffs_insert_node(c, f, &raw_inode, f->name, new_node);
	jffs_fm_write_unlock(fmc);

	D3(printk("jffs_rewrite_data(): Leaving...\n"));
	return 0;
} /* jffs_rewrite_data()  */


/* jffs_garbage_collect_next implements one step in the garbage collect
   process and is often called multiple times at each occasion of a
   garbage collect.  */

static int
jffs_garbage_collect_next(struct jffs_control *c)
{
	struct jffs_fmcontrol *fmc = c->fmc;
	struct jffs_node *node;
	struct jffs_file *f;
	int err = 0;
	__u32 size;
	__u32 data_size;
	__u32 total_name_size;
	__u32 extra_available;
	__u32 space_needed;
	__u32 free_chunk_size1 = jffs_free_size1(fmc);
	D2(__u32 free_chunk_size2 = jffs_free_size2(fmc));

	/* Get the oldest node in the flash.  */
	node = jffs_get_oldest_node(fmc);
	ASSERT(if (!node) {
		printk(KERN_ERR "JFFS: jffs_garbage_collect_next: "
		       "No oldest node found!\n");
                err = -1;
                goto jffs_garbage_collect_next_end;
		

	});

	/* Find its corresponding file too.  */
	f = jffs_find_file(c, node->ino);

	if (!f) {
	  printk (KERN_ERR "JFFS: jffs_garbage_collect_next: "
                  "No file to garbage collect! "
		  "(ino = 0x%08x)\n", node->ino);
          /* FIXME: Free the offending node and recover. */
          err = -1;
          goto jffs_garbage_collect_next_end;
	}

	/* We always write out the name. Theoretically, we don't need
	   to, but for now it's easier - because otherwise we'd have
	   to keep track of how many times the current name exists on
	   the flash and make sure it never reaches zero.

	   The current approach means that would be possible to cause
	   the GC to end up eating its tail by writing lots of nodes
	   with no name for it to garbage-collect. Hence the change in
	   inode.c to write names with _every_ node.

	   It sucks, but it _should_ work.
	*/
	total_name_size = JFFS_PAD(f->nsize);

	D1(printk("jffs_garbage_collect_next(): \"%s\", "
		  "ino: %u, version: %u, location 0x%x, dsize %u\n",
		  (f->name ? f->name : ""), node->ino, node->version, 
		  node->fm->offset, node->data_size));

	/* Compute how many data it's possible to rewrite at the moment.  */
	data_size = f->size - node->data_offset;

	/* And from that, the total size of the chunk we want to write */
	size = sizeof(struct jffs_raw_inode) + total_name_size
	       + data_size + JFFS_GET_PAD_BYTES(data_size);

	/* If that's more than max_chunk_size, reduce it accordingly */
	if (size > fmc->max_chunk_size) {
		size = fmc->max_chunk_size;
		data_size = size - sizeof(struct jffs_raw_inode)
			    - total_name_size;
	}

	/* If we're asking to take up more space than free_chunk_size1
	   but we _could_ fit in it, shrink accordingly.
	*/
	if (size > free_chunk_size1) {

		if (free_chunk_size1 <
		    (sizeof(struct jffs_raw_inode) + total_name_size + BLOCK_SIZE)){
			/* The space left is too small to be of any
			   use really.  */
			struct jffs_fm *dirty_fm
			= jffs_fmalloced(fmc,
					 fmc->tail->offset + fmc->tail->size,
					 free_chunk_size1, NULL);
			if (!dirty_fm) {
				printk(KERN_ERR "JFFS: "
				       "jffs_garbage_collect_next: "
				       "Failed to allocate `dirty' "
				       "flash memory!\n");
				err = -1;
                                goto jffs_garbage_collect_next_end;
			}
			D1(printk("Dirtying end of flash - too small\n"));
			jffs_write_dummy_node(c, dirty_fm);
                        err = 0;
			goto jffs_garbage_collect_next_end;
		}
		D1(printk("Reducing size of new node from %d to %d to avoid "
			  " exceeding free_chunk_size1\n",
			  size, free_chunk_size1));

		size = free_chunk_size1;
		data_size = size - sizeof(struct jffs_raw_inode)
			    - total_name_size;
	}


	/* Calculate the amount of space needed to hold the nodes
	   which are remaining in the tail */
	space_needed = fmc->min_free_size - (node->fm->offset % fmc->sector_size);

	/* From that, calculate how much 'extra' space we can use to
	   increase the size of the node we're writing from the size
	   of the node we're obsoleting
	*/
	if (space_needed > fmc->free_size) {
		/* If we've gone below min_free_size for some reason,
		   don't fuck up. This is why we have 
		   min_free_size > sector_size. Whinge about it though,
		   just so I can convince myself my maths is right.
		*/
		D1(printk(KERN_WARNING "jffs_garbage_collect_next(): "
			  "space_needed %d exceeded free_size %d\n",
			  space_needed, fmc->free_size));
		extra_available = 0;
	} else {
		extra_available = fmc->free_size - space_needed;
	}

	/* Check that we don't use up any more 'extra' space than
	   what's available */
	if (size > JFFS_PAD(node->data_size) + total_name_size + 
	    sizeof(struct jffs_raw_inode) + extra_available) {
		D1(printk("Reducing size of new node from %d to %ld to avoid "
		       "catching our tail\n", size, 
			  (long) (JFFS_PAD(node->data_size) + JFFS_PAD(node->name_size) + 
			  sizeof(struct jffs_raw_inode) + extra_available)));
		D1(printk("space_needed = %d, extra_available = %d\n", 
			  space_needed, extra_available));

		size = JFFS_PAD(node->data_size) + total_name_size + 
		  sizeof(struct jffs_raw_inode) + extra_available;
		data_size = size - sizeof(struct jffs_raw_inode)
			- total_name_size;
	};

	D2(printk("  total_name_size: %u\n", total_name_size));
	D2(printk("  data_size: %u\n", data_size));
	D2(printk("  size: %u\n", size));
	D2(printk("  f->nsize: %u\n", f->nsize));
	D2(printk("  f->size: %u\n", f->size));
	D2(printk("  node->data_offset: %u\n", node->data_offset));
	D2(printk("  free_chunk_size1: %u\n", free_chunk_size1));
	D2(printk("  free_chunk_size2: %u\n", free_chunk_size2));
	D2(printk("  node->fm->offset: 0x%08x\n", node->fm->offset));

	if ((err = jffs_rewrite_data(f, node, data_size))) {
		printk(KERN_WARNING "jffs_rewrite_data() failed: %d\n", err);
		return err;
	}
	  
jffs_garbage_collect_next_end:
	D3(printk("jffs_garbage_collect_next: Leaving...\n"));
	return err;
} /* jffs_garbage_collect_next */


/* If an obsolete node is partly going to be erased due to garbage
   collection, the part that isn't going to be erased must be filled
   with zeroes so that the scan of the flash will work smoothly next
   time.  (The data in the file could for instance be a JFFS image
   which could cause enormous confusion during a scan of the flash
   device if we didn't do this.)
     There are two phases in this procedure: First, the clearing of
   the name and data parts of the node. Second, possibly also clearing
   a part of the raw inode as well.  If the box is power cycled during
   the first phase, only the checksum of this node-to-be-cleared-at-
   the-end will be wrong.  If the box is power cycled during, or after,
   the clearing of the raw inode, the information like the length of
   the name and data parts are zeroed.  The next time the box is
   powered up, the scanning algorithm manages this faulty data too
   because:

   - The checksum is invalid and thus the raw inode must be discarded
     in any case.
   - If the lengths of the data part or the name part are zeroed, the
     scanning just continues after the raw inode.  But after the inode
     the scanning procedure just finds zeroes which is the same as
     dirt.

   So, in the end, this could never fail. :-)  Even if it does fail,
   the scanning algorithm should manage that too.  */

static int
jffs_clear_end_of_node(struct jffs_control *c, __u32 erase_size)
{
	struct jffs_fm *fm;
	struct jffs_fmcontrol *fmc = c->fmc;
	__u32 zero_offset;
	__u32 zero_size;
	__u32 zero_offset_data;
	__u32 zero_size_data;
	__u32 cutting_raw_inode = 0;

	if (!(fm = jffs_cut_node(fmc, erase_size))) {
		D3(printk("jffs_clear_end_of_node(): fm == NULL\n"));
		return 0;
	}

	/* Where and how much shall we clear?  */
	zero_offset = fmc->head->offset + erase_size;
	zero_size = fm->offset + fm->size - zero_offset;

	/* Do we have to clear the raw_inode explicitly?  */
	if (fm->size - zero_size < sizeof(struct jffs_raw_inode)) {
		cutting_raw_inode = sizeof(struct jffs_raw_inode)
				    - (fm->size - zero_size);
	}

	/* First, clear the name and data fields.  */
	zero_offset_data = zero_offset + cutting_raw_inode;
	zero_size_data = zero_size - cutting_raw_inode;
	flash_safe_acquire(fmc->mtd);
	flash_memset(fmc->mtd, zero_offset_data, 0, zero_size_data);
	flash_safe_release(fmc->mtd);

	/* Should we clear a part of the raw inode?  */
	if (cutting_raw_inode) {
		/* I guess it is ok to clear the raw inode in this order.  */
		flash_safe_acquire(fmc->mtd);
		flash_memset(fmc->mtd, zero_offset, 0,
			     cutting_raw_inode);
		flash_safe_release(fmc->mtd);
	}

	return 0;
} /* jffs_clear_end_of_node()  */

/* Try to erase as much as possible of the dirt in the flash memory.  */
static long
jffs_try_to_erase(struct jffs_control *c)
{
	struct jffs_fmcontrol *fmc = c->fmc;
	long erase_size;
	int err;
	__u32 offset;

	D3(printk("jffs_try_to_erase()\n"));

	erase_size = jffs_erasable_size(fmc);

	D2(printk("jffs_try_to_erase(): erase_size = %ld\n", erase_size));

	if (erase_size == 0) {
		return 0;
	}
	else if (erase_size < 0) {
		printk(KERN_ERR "JFFS: jffs_try_to_erase: "
		       "jffs_erasable_size returned %ld.\n", erase_size);
		return erase_size;
	}

	if ((err = jffs_clear_end_of_node(c, erase_size)) < 0) {
		printk(KERN_ERR "JFFS: jffs_try_to_erase: "
		       "Clearing of node failed.\n");
		return err;
	}

	offset = fmc->head->offset;

	/* Now, let's try to do the erase.  */
	if ((err = flash_erase_region(fmc->mtd,
				      offset, erase_size)) < 0) {
		printk(KERN_ERR "JFFS: Erase of flash failed. "
		       "offset = %u, erase_size = %ld\n",
		       offset, erase_size);
		/* XXX: Here we should allocate this area as dirty
		   with jffs_fmalloced or something similar.  Now
		   we just report the error.  */
		return err;
	}

#if 0
	/* Check if the erased sectors really got erased.  */
	{
		__u32 pos;
		__u32 end;

		pos = (__u32)flash_get_direct_pointer(to_kdev_t(c->sb->s_dev), offset);
		end = pos + erase_size;

		D2(printk("JFFS: Checking erased sector(s)...\n"));

		flash_safe_acquire(fmc->mtd);

		for (; pos < end; pos += 4) {
			if (*(__u32 *)pos != JFFS_EMPTY_BITMASK) {
				printk("JFFS: Erase failed! pos = 0x%lx\n",
				       (long)pos);
				jffs_hexdump(fmc->mtd, pos,
					     jffs_min(256, end - pos));
				err = -1;
				break;
			}
		}

		flash_safe_release(fmc->mtd);

		if (!err) {
			D2(printk("JFFS: Erase succeeded.\n"));
		}
		else {
			/* XXX: Here we should allocate the memory
			   with jffs_fmalloced() in order to prevent
			   JFFS from using this area accidentally.  */
			return err;
		}
	}
#endif

	/* Update the flash memory data structures.  */
	jffs_sync_erase(fmc, erase_size);

	return erase_size;
}


/* There are different criteria that should trigger a garbage collect:

   1. There is too much dirt in the memory.
   2. The free space is becoming small.
   3. There are many versions of a node.

   The garbage collect should always be done in a manner that guarantees
   that future garbage collects cannot be locked.  E.g. Rewritten chunks
   should not be too large (span more than one sector in the flash memory
   for exemple).  Of course there is a limit on how intelligent this garbage
   collection can be.  */


static int
jffs_garbage_collect_now(struct jffs_control *c)
{
	struct jffs_fmcontrol *fmc = c->fmc;
	long erased = 0;
	int result = 0;
	D1(int i = 1);
	D2(printk("***jffs_garbage_collect_now(): fmc->dirty_size = %u, fmc->free_size = 0x%x\n, fcs1=0x%x, fcs2=0x%x",
		  fmc->dirty_size, fmc->free_size, jffs_free_size1(fmc), jffs_free_size2(fmc)));
	D2(jffs_print_fmcontrol(fmc));

	//	down(&fmc->gclock);

	/* If it is possible to garbage collect, do so.  */
	
	while (erased == 0) {
		D1(printk("***jffs_garbage_collect_now(): round #%u, "
			  "fmc->dirty_size = %u\n", i++, fmc->dirty_size));
		D2(jffs_print_fmcontrol(fmc));

		if ((erased = jffs_try_to_erase(c)) < 0) {
			printk(KERN_WARNING "JFFS: Error in "
			       "garbage collector.\n");
			result = erased;
			goto gc_end;
		}
		if (erased)
			break;
		
		if (fmc->free_size == 0) {
			/* Argh */
			printk(KERN_ERR "jffs_garbage_collect_now(): free_size == 0. This is BAD.\n");
			result = -ENOSPC;
			break;
		}

		if (fmc->dirty_size < fmc->sector_size) {
			/* Actually, we _may_ have been able to free some, 
			 * if there are many overlapping nodes which aren't
			 * actually marked dirty because they still have
			 * some valid data in each.
			 */
			result = -ENOSPC;
			break;
		}

		/* Let's dare to make a garbage collect.  */
		if ((result = jffs_garbage_collect_next(c)) < 0) {
			printk(KERN_ERR "JFFS: Something "
			       "has gone seriously wrong "
			       "with a garbage collect.\n");
			goto gc_end;
		}

		D1(printk("   jffs_garbage_collect_now(): erased: %ld\n", erased));
		DJM(jffs_print_memory_allocation_statistics());
	}
	
gc_end:
	//	up(&fmc->gclock);

	D3(printk("   jffs_garbage_collect_now(): Leaving...\n"));
	D1(if (erased) {
		printk("jffs_g_c_now(): erased = %ld\n", erased);
		jffs_print_fmcontrol(fmc);
	});

	if (!erased && !result)
		return -ENOSPC;

	return result;
} /* jffs_garbage_collect_now() */


/* Determine if it is reasonable to start garbage collection.
   We start a gc pass if either:
   - The number of free bytes < MIN_FREE_BYTES && at least one
     block is dirty, OR
   - The number of dirty bytes > MAX_DIRTY_BYTES
*/
static inline int thread_should_wake (struct jffs_control *c)
{
	D1(printk (KERN_NOTICE "thread_should_wake(): free=%d, dirty=%d, blocksize=%d.\n",
		   c->fmc->free_size, c->fmc->dirty_size, c->fmc->sector_size));

	/* If there's not enough dirty space to free a block, there's no point. */
	if (c->fmc->dirty_size < c->fmc->sector_size) {
		D2(printk(KERN_NOTICE "thread_should_wake(): Not waking. Insufficient dirty space\n"));
		return 0;
	}
#if 1
	/* If there is too much RAM used by the various structures, GC */
	if (jffs_get_node_inuse() > (c->fmc->used_size/c->fmc->max_chunk_size * 5 + jffs_get_file_count() * 2 + 50)) {
		/* FIXME: Provide proof that this test can be satisfied. We
		   don't want a filesystem doing endless GC just because this
		   condition cannot ever be false.
		*/
		D2(printk(KERN_NOTICE "thread_should_wake(): Waking due to number of nodes\n"));
		return 1;
	}
#endif
	/* If there are fewer free bytes than the threshold, GC */
	if (c->fmc->free_size < c->gc_minfree_threshold) {
		D2(printk(KERN_NOTICE "thread_should_wake(): Waking due to insufficent free space\n"));
		return 1;
	}
	/* If there are more dirty bytes than the threshold, GC */
	if (c->fmc->dirty_size > c->gc_maxdirty_threshold) {
		D2(printk(KERN_NOTICE "thread_should_wake(): Waking due to excessive dirty space\n"));
		return 1;
	}	
	/* FIXME: What about the "There are many versions of a node" condition? */

	return 0;
}


void jffs_garbage_collect_trigger(struct jffs_control *c)
{
	/* NOTE: We rely on the fact that we have the BKL here.
	 * Otherwise, the gc_task could go away between the check
	 * and the wake_up_process()
	 */
	if (c->gc_task && thread_should_wake(c))
		send_sig(SIGHUP, c->gc_task, 1);
}
  

/* Kernel threads  take (void *) as arguments.   Thus we pass
   the jffs_control data as a (void *) and then cast it. */
int
jffs_garbage_collect_thread(void *ptr)
{
        struct jffs_control *c = (struct jffs_control *) ptr;
	struct jffs_fmcontrol *fmc = c->fmc;
	long erased;
	int result = 0;
	D1(int i = 1);

	daemonize("jffs_gcd");

	c->gc_task = current;

	lock_kernel();
	init_completion(&c->gc_thread_comp); /* barrier */ 
	spin_lock_irq(&current->sighand->siglock);
	siginitsetinv (&current->blocked, sigmask(SIGHUP) | sigmask(SIGKILL) | sigmask(SIGSTOP) | sigmask(SIGCONT));
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	D1(printk (KERN_NOTICE "jffs_garbage_collect_thread(): Starting infinite loop.\n"));

	for (;;) {

		/* See if we need to start gc.  If we don't, go to sleep.
		   
		   Current implementation is a BAD THING(tm).  If we try 
		   to unmount the FS, the unmount operation will sleep waiting
		   for this thread to exit.  We need to arrange to send it a
		   sig before the umount process sleeps.
		*/

		if (!thread_should_wake(c))
			set_current_state (TASK_INTERRUPTIBLE);
		
		schedule(); /* Yes, we do this even if we want to go
				       on immediately - we're a low priority 
				       background task. */

		/* Put_super will send a SIGKILL and then wait on the sem. 
		 */
		while (signal_pending(current)) {
			siginfo_t info;
			unsigned long signr = 0;

			if (try_to_freeze())
				continue;

			spin_lock_irq(&current->sighand->siglock);
			signr = dequeue_signal(current, &current->blocked, &info);
			spin_unlock_irq(&current->sighand->siglock);

			switch(signr) {
			case SIGSTOP:
				D1(printk("jffs_garbage_collect_thread(): SIGSTOP received.\n"));
				set_current_state(TASK_STOPPED);
				schedule();
				break;

			case SIGKILL:
				D1(printk("jffs_garbage_collect_thread(): SIGKILL received.\n"));
				c->gc_task = NULL;
				complete_and_exit(&c->gc_thread_comp, 0);
			}
		}


		D1(printk (KERN_NOTICE "jffs_garbage_collect_thread(): collecting.\n"));

		D3(printk (KERN_NOTICE "g_c_thread(): down biglock\n"));
		down(&fmc->biglock);
		
		D1(printk("***jffs_garbage_collect_thread(): round #%u, "
			  "fmc->dirty_size = %u\n", i++, fmc->dirty_size));
		D2(jffs_print_fmcontrol(fmc));

		if ((erased = jffs_try_to_erase(c)) < 0) {
			printk(KERN_WARNING "JFFS: Error in "
			       "garbage collector: %ld.\n", erased);
		}

		if (erased)
			goto gc_end;

		if (fmc->free_size == 0) {
			/* Argh. Might as well commit suicide. */
			printk(KERN_ERR "jffs_garbage_collect_thread(): free_size == 0. This is BAD.\n");
			send_sig(SIGQUIT, c->gc_task, 1);
			// panic()
			goto gc_end;
		}
		
		/* Let's dare to make a garbage collect.  */
		if ((result = jffs_garbage_collect_next(c)) < 0) {
			printk(KERN_ERR "JFFS: Something "
			       "has gone seriously wrong "
			       "with a garbage collect: %d\n", result);
		}
		
	gc_end:
		D3(printk (KERN_NOTICE "g_c_thread(): up biglock\n"));
		up(&fmc->biglock);
	} /* for (;;) */
} /* jffs_garbage_collect_thread() */
OpenPOWER on IntegriCloud