aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ext4/extents.c
blob: e910720e8bb8e32b5f2a1306ec1005629e5c6fd4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
/*
 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
 * Written by Alex Tomas <alex@clusterfs.com>
 *
 * Architecture independence:
 *   Copyright (c) 2005, Bull S.A.
 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 */

/*
 * Extents support for EXT4
 *
 * TODO:
 *   - ext4*_error() should be used in some situations
 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
 *   - smart tree reduction
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/jbd2.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/falloc.h>
#include <asm/uaccess.h>
#include <linux/fiemap.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"

static int ext4_ext_truncate_extend_restart(handle_t *handle,
					    struct inode *inode,
					    int needed)
{
	int err;

	if (!ext4_handle_valid(handle))
		return 0;
	if (handle->h_buffer_credits > needed)
		return 0;
	err = ext4_journal_extend(handle, needed);
	if (err <= 0)
		return err;
	err = ext4_truncate_restart_trans(handle, inode, needed);
	if (err == 0)
		err = -EAGAIN;

	return err;
}

/*
 * could return:
 *  - EROFS
 *  - ENOMEM
 */
static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
				struct ext4_ext_path *path)
{
	if (path->p_bh) {
		/* path points to block */
		return ext4_journal_get_write_access(handle, path->p_bh);
	}
	/* path points to leaf/index in inode body */
	/* we use in-core data, no need to protect them */
	return 0;
}

/*
 * could return:
 *  - EROFS
 *  - ENOMEM
 *  - EIO
 */
static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
				struct ext4_ext_path *path)
{
	int err;
	if (path->p_bh) {
		/* path points to block */
		err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
	} else {
		/* path points to leaf/index in inode body */
		err = ext4_mark_inode_dirty(handle, inode);
	}
	return err;
}

static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
			      struct ext4_ext_path *path,
			      ext4_lblk_t block)
{
	struct ext4_inode_info *ei = EXT4_I(inode);
	ext4_fsblk_t bg_start;
	ext4_fsblk_t last_block;
	ext4_grpblk_t colour;
	ext4_group_t block_group;
	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
	int depth;

	if (path) {
		struct ext4_extent *ex;
		depth = path->p_depth;

		/*
		 * Try to predict block placement assuming that we are
		 * filling in a file which will eventually be
		 * non-sparse --- i.e., in the case of libbfd writing
		 * an ELF object sections out-of-order but in a way
		 * the eventually results in a contiguous object or
		 * executable file, or some database extending a table
		 * space file.  However, this is actually somewhat
		 * non-ideal if we are writing a sparse file such as
		 * qemu or KVM writing a raw image file that is going
		 * to stay fairly sparse, since it will end up
		 * fragmenting the file system's free space.  Maybe we
		 * should have some hueristics or some way to allow
		 * userspace to pass a hint to file system,
		 * especiially if the latter case turns out to be
		 * common.
		 */
		ex = path[depth].p_ext;
		if (ex) {
			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);

			if (block > ext_block)
				return ext_pblk + (block - ext_block);
			else
				return ext_pblk - (ext_block - block);
		}

		/* it looks like index is empty;
		 * try to find starting block from index itself */
		if (path[depth].p_bh)
			return path[depth].p_bh->b_blocknr;
	}

	/* OK. use inode's group */
	block_group = ei->i_block_group;
	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
		/*
		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
		 * block groups per flexgroup, reserve the first block
		 * group for directories and special files.  Regular
		 * files will start at the second block group.  This
		 * tends to speed up directory access and improves
		 * fsck times.
		 */
		block_group &= ~(flex_size-1);
		if (S_ISREG(inode->i_mode))
			block_group++;
	}
	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;

	/*
	 * If we are doing delayed allocation, we don't need take
	 * colour into account.
	 */
	if (test_opt(inode->i_sb, DELALLOC))
		return bg_start;

	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
		colour = (current->pid % 16) *
			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
	else
		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
	return bg_start + colour + block;
}

/*
 * Allocation for a meta data block
 */
static ext4_fsblk_t
ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
			struct ext4_ext_path *path,
			struct ext4_extent *ex, int *err)
{
	ext4_fsblk_t goal, newblock;

	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
	newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
	return newblock;
}

static inline int ext4_ext_space_block(struct inode *inode, int check)
{
	int size;

	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
			/ sizeof(struct ext4_extent);
	if (!check) {
#ifdef AGGRESSIVE_TEST
		if (size > 6)
			size = 6;
#endif
	}
	return size;
}

static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
{
	int size;

	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
			/ sizeof(struct ext4_extent_idx);
	if (!check) {
#ifdef AGGRESSIVE_TEST
		if (size > 5)
			size = 5;
#endif
	}
	return size;
}

static inline int ext4_ext_space_root(struct inode *inode, int check)
{
	int size;

	size = sizeof(EXT4_I(inode)->i_data);
	size -= sizeof(struct ext4_extent_header);
	size /= sizeof(struct ext4_extent);
	if (!check) {
#ifdef AGGRESSIVE_TEST
		if (size > 3)
			size = 3;
#endif
	}
	return size;
}

static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
{
	int size;

	size = sizeof(EXT4_I(inode)->i_data);
	size -= sizeof(struct ext4_extent_header);
	size /= sizeof(struct ext4_extent_idx);
	if (!check) {
#ifdef AGGRESSIVE_TEST
		if (size > 4)
			size = 4;
#endif
	}
	return size;
}

/*
 * Calculate the number of metadata blocks needed
 * to allocate @blocks
 * Worse case is one block per extent
 */
int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
{
	struct ext4_inode_info *ei = EXT4_I(inode);
	int idxs, num = 0;

	idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
		/ sizeof(struct ext4_extent_idx));

	/*
	 * If the new delayed allocation block is contiguous with the
	 * previous da block, it can share index blocks with the
	 * previous block, so we only need to allocate a new index
	 * block every idxs leaf blocks.  At ldxs**2 blocks, we need
	 * an additional index block, and at ldxs**3 blocks, yet
	 * another index blocks.
	 */
	if (ei->i_da_metadata_calc_len &&
	    ei->i_da_metadata_calc_last_lblock+1 == lblock) {
		if ((ei->i_da_metadata_calc_len % idxs) == 0)
			num++;
		if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
			num++;
		if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
			num++;
			ei->i_da_metadata_calc_len = 0;
		} else
			ei->i_da_metadata_calc_len++;
		ei->i_da_metadata_calc_last_lblock++;
		return num;
	}

	/*
	 * In the worst case we need a new set of index blocks at
	 * every level of the inode's extent tree.
	 */
	ei->i_da_metadata_calc_len = 1;
	ei->i_da_metadata_calc_last_lblock = lblock;
	return ext_depth(inode) + 1;
}

static int
ext4_ext_max_entries(struct inode *inode, int depth)
{
	int max;

	if (depth == ext_depth(inode)) {
		if (depth == 0)
			max = ext4_ext_space_root(inode, 1);
		else
			max = ext4_ext_space_root_idx(inode, 1);
	} else {
		if (depth == 0)
			max = ext4_ext_space_block(inode, 1);
		else
			max = ext4_ext_space_block_idx(inode, 1);
	}

	return max;
}

static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
{
	ext4_fsblk_t block = ext4_ext_pblock(ext);
	int len = ext4_ext_get_actual_len(ext);

	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
}

static int ext4_valid_extent_idx(struct inode *inode,
				struct ext4_extent_idx *ext_idx)
{
	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);

	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
}

static int ext4_valid_extent_entries(struct inode *inode,
				struct ext4_extent_header *eh,
				int depth)
{
	struct ext4_extent *ext;
	struct ext4_extent_idx *ext_idx;
	unsigned short entries;
	if (eh->eh_entries == 0)
		return 1;

	entries = le16_to_cpu(eh->eh_entries);

	if (depth == 0) {
		/* leaf entries */
		ext = EXT_FIRST_EXTENT(eh);
		while (entries) {
			if (!ext4_valid_extent(inode, ext))
				return 0;
			ext++;
			entries--;
		}
	} else {
		ext_idx = EXT_FIRST_INDEX(eh);
		while (entries) {
			if (!ext4_valid_extent_idx(inode, ext_idx))
				return 0;
			ext_idx++;
			entries--;
		}
	}
	return 1;
}

static int __ext4_ext_check(const char *function, unsigned int line,
			    struct inode *inode, struct ext4_extent_header *eh,
			    int depth)
{
	const char *error_msg;
	int max = 0;

	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
		error_msg = "invalid magic";
		goto corrupted;
	}
	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
		error_msg = "unexpected eh_depth";
		goto corrupted;
	}
	if (unlikely(eh->eh_max == 0)) {
		error_msg = "invalid eh_max";
		goto corrupted;
	}
	max = ext4_ext_max_entries(inode, depth);
	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
		error_msg = "too large eh_max";
		goto corrupted;
	}
	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
		error_msg = "invalid eh_entries";
		goto corrupted;
	}
	if (!ext4_valid_extent_entries(inode, eh, depth)) {
		error_msg = "invalid extent entries";
		goto corrupted;
	}
	return 0;

corrupted:
	ext4_error_inode(inode, function, line, 0,
			"bad header/extent: %s - magic %x, "
			"entries %u, max %u(%u), depth %u(%u)",
			error_msg, le16_to_cpu(eh->eh_magic),
			le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
			max, le16_to_cpu(eh->eh_depth), depth);

	return -EIO;
}

#define ext4_ext_check(inode, eh, depth)	\
	__ext4_ext_check(__func__, __LINE__, inode, eh, depth)

int ext4_ext_check_inode(struct inode *inode)
{
	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
}

#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
{
	int k, l = path->p_depth;

	ext_debug("path:");
	for (k = 0; k <= l; k++, path++) {
		if (path->p_idx) {
		  ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
			    ext4_idx_pblock(path->p_idx));
		} else if (path->p_ext) {
			ext_debug("  %d:[%d]%d:%llu ",
				  le32_to_cpu(path->p_ext->ee_block),
				  ext4_ext_is_uninitialized(path->p_ext),
				  ext4_ext_get_actual_len(path->p_ext),
				  ext4_ext_pblock(path->p_ext));
		} else
			ext_debug("  []");
	}
	ext_debug("\n");
}

static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
{
	int depth = ext_depth(inode);
	struct ext4_extent_header *eh;
	struct ext4_extent *ex;
	int i;

	if (!path)
		return;

	eh = path[depth].p_hdr;
	ex = EXT_FIRST_EXTENT(eh);

	ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);

	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
		ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
			  ext4_ext_is_uninitialized(ex),
			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
	}
	ext_debug("\n");
}
#else
#define ext4_ext_show_path(inode, path)
#define ext4_ext_show_leaf(inode, path)
#endif

void ext4_ext_drop_refs(struct ext4_ext_path *path)
{
	int depth = path->p_depth;
	int i;

	for (i = 0; i <= depth; i++, path++)
		if (path->p_bh) {
			brelse(path->p_bh);
			path->p_bh = NULL;
		}
}

/*
 * ext4_ext_binsearch_idx:
 * binary search for the closest index of the given block
 * the header must be checked before calling this
 */
static void
ext4_ext_binsearch_idx(struct inode *inode,
			struct ext4_ext_path *path, ext4_lblk_t block)
{
	struct ext4_extent_header *eh = path->p_hdr;
	struct ext4_extent_idx *r, *l, *m;


	ext_debug("binsearch for %u(idx):  ", block);

	l = EXT_FIRST_INDEX(eh) + 1;
	r = EXT_LAST_INDEX(eh);
	while (l <= r) {
		m = l + (r - l) / 2;
		if (block < le32_to_cpu(m->ei_block))
			r = m - 1;
		else
			l = m + 1;
		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
				m, le32_to_cpu(m->ei_block),
				r, le32_to_cpu(r->ei_block));
	}

	path->p_idx = l - 1;
	ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
		  ext4_idx_pblock(path->p_idx));

#ifdef CHECK_BINSEARCH
	{
		struct ext4_extent_idx *chix, *ix;
		int k;

		chix = ix = EXT_FIRST_INDEX(eh);
		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
		  if (k != 0 &&
		      le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
				printk(KERN_DEBUG "k=%d, ix=0x%p, "
				       "first=0x%p\n", k,
				       ix, EXT_FIRST_INDEX(eh));
				printk(KERN_DEBUG "%u <= %u\n",
				       le32_to_cpu(ix->ei_block),
				       le32_to_cpu(ix[-1].ei_block));
			}
			BUG_ON(k && le32_to_cpu(ix->ei_block)
					   <= le32_to_cpu(ix[-1].ei_block));
			if (block < le32_to_cpu(ix->ei_block))
				break;
			chix = ix;
		}
		BUG_ON(chix != path->p_idx);
	}
#endif

}

/*
 * ext4_ext_binsearch:
 * binary search for closest extent of the given block
 * the header must be checked before calling this
 */
static void
ext4_ext_binsearch(struct inode *inode,
		struct ext4_ext_path *path, ext4_lblk_t block)
{
	struct ext4_extent_header *eh = path->p_hdr;
	struct ext4_extent *r, *l, *m;

	if (eh->eh_entries == 0) {
		/*
		 * this leaf is empty:
		 * we get such a leaf in split/add case
		 */
		return;
	}

	ext_debug("binsearch for %u:  ", block);

	l = EXT_FIRST_EXTENT(eh) + 1;
	r = EXT_LAST_EXTENT(eh);

	while (l <= r) {
		m = l + (r - l) / 2;
		if (block < le32_to_cpu(m->ee_block))
			r = m - 1;
		else
			l = m + 1;
		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
				m, le32_to_cpu(m->ee_block),
				r, le32_to_cpu(r->ee_block));
	}

	path->p_ext = l - 1;
	ext_debug("  -> %d:%llu:[%d]%d ",
			le32_to_cpu(path->p_ext->ee_block),
			ext4_ext_pblock(path->p_ext),
			ext4_ext_is_uninitialized(path->p_ext),
			ext4_ext_get_actual_len(path->p_ext));

#ifdef CHECK_BINSEARCH
	{
		struct ext4_extent *chex, *ex;
		int k;

		chex = ex = EXT_FIRST_EXTENT(eh);
		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
			BUG_ON(k && le32_to_cpu(ex->ee_block)
					  <= le32_to_cpu(ex[-1].ee_block));
			if (block < le32_to_cpu(ex->ee_block))
				break;
			chex = ex;
		}
		BUG_ON(chex != path->p_ext);
	}
#endif

}

int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
{
	struct ext4_extent_header *eh;

	eh = ext_inode_hdr(inode);
	eh->eh_depth = 0;
	eh->eh_entries = 0;
	eh->eh_magic = EXT4_EXT_MAGIC;
	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
	ext4_mark_inode_dirty(handle, inode);
	ext4_ext_invalidate_cache(inode);
	return 0;
}

struct ext4_ext_path *
ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
					struct ext4_ext_path *path)
{
	struct ext4_extent_header *eh;
	struct buffer_head *bh;
	short int depth, i, ppos = 0, alloc = 0;

	eh = ext_inode_hdr(inode);
	depth = ext_depth(inode);

	/* account possible depth increase */
	if (!path) {
		path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
				GFP_NOFS);
		if (!path)
			return ERR_PTR(-ENOMEM);
		alloc = 1;
	}
	path[0].p_hdr = eh;
	path[0].p_bh = NULL;

	i = depth;
	/* walk through the tree */
	while (i) {
		int need_to_validate = 0;

		ext_debug("depth %d: num %d, max %d\n",
			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));

		ext4_ext_binsearch_idx(inode, path + ppos, block);
		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
		path[ppos].p_depth = i;
		path[ppos].p_ext = NULL;

		bh = sb_getblk(inode->i_sb, path[ppos].p_block);
		if (unlikely(!bh))
			goto err;
		if (!bh_uptodate_or_lock(bh)) {
			if (bh_submit_read(bh) < 0) {
				put_bh(bh);
				goto err;
			}
			/* validate the extent entries */
			need_to_validate = 1;
		}
		eh = ext_block_hdr(bh);
		ppos++;
		if (unlikely(ppos > depth)) {
			put_bh(bh);
			EXT4_ERROR_INODE(inode,
					 "ppos %d > depth %d", ppos, depth);
			goto err;
		}
		path[ppos].p_bh = bh;
		path[ppos].p_hdr = eh;
		i--;

		if (need_to_validate && ext4_ext_check(inode, eh, i))
			goto err;
	}

	path[ppos].p_depth = i;
	path[ppos].p_ext = NULL;
	path[ppos].p_idx = NULL;

	/* find extent */
	ext4_ext_binsearch(inode, path + ppos, block);
	/* if not an empty leaf */
	if (path[ppos].p_ext)
		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);

	ext4_ext_show_path(inode, path);

	return path;

err:
	ext4_ext_drop_refs(path);
	if (alloc)
		kfree(path);
	return ERR_PTR(-EIO);
}

/*
 * ext4_ext_insert_index:
 * insert new index [@logical;@ptr] into the block at @curp;
 * check where to insert: before @curp or after @curp
 */
static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
				 struct ext4_ext_path *curp,
				 int logical, ext4_fsblk_t ptr)
{
	struct ext4_extent_idx *ix;
	int len, err;

	err = ext4_ext_get_access(handle, inode, curp);
	if (err)
		return err;

	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
		EXT4_ERROR_INODE(inode,
				 "logical %d == ei_block %d!",
				 logical, le32_to_cpu(curp->p_idx->ei_block));
		return -EIO;
	}
	len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
		/* insert after */
		if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
			len = (len - 1) * sizeof(struct ext4_extent_idx);
			len = len < 0 ? 0 : len;
			ext_debug("insert new index %d after: %llu. "
					"move %d from 0x%p to 0x%p\n",
					logical, ptr, len,
					(curp->p_idx + 1), (curp->p_idx + 2));
			memmove(curp->p_idx + 2, curp->p_idx + 1, len);
		}
		ix = curp->p_idx + 1;
	} else {
		/* insert before */
		len = len * sizeof(struct ext4_extent_idx);
		len = len < 0 ? 0 : len;
		ext_debug("insert new index %d before: %llu. "
				"move %d from 0x%p to 0x%p\n",
				logical, ptr, len,
				curp->p_idx, (curp->p_idx + 1));
		memmove(curp->p_idx + 1, curp->p_idx, len);
		ix = curp->p_idx;
	}

	ix->ei_block = cpu_to_le32(logical);
	ext4_idx_store_pblock(ix, ptr);
	le16_add_cpu(&curp->p_hdr->eh_entries, 1);

	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
			     > le16_to_cpu(curp->p_hdr->eh_max))) {
		EXT4_ERROR_INODE(inode,
				 "logical %d == ei_block %d!",
				 logical, le32_to_cpu(curp->p_idx->ei_block));
		return -EIO;
	}
	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
		return -EIO;
	}

	err = ext4_ext_dirty(handle, inode, curp);
	ext4_std_error(inode->i_sb, err);

	return err;
}

/*
 * ext4_ext_split:
 * inserts new subtree into the path, using free index entry
 * at depth @at:
 * - allocates all needed blocks (new leaf and all intermediate index blocks)
 * - makes decision where to split
 * - moves remaining extents and index entries (right to the split point)
 *   into the newly allocated blocks
 * - initializes subtree
 */
static int ext4_ext_split(handle_t *handle, struct inode *inode,
				struct ext4_ext_path *path,
				struct ext4_extent *newext, int at)
{
	struct buffer_head *bh = NULL;
	int depth = ext_depth(inode);
	struct ext4_extent_header *neh;
	struct ext4_extent_idx *fidx;
	struct ext4_extent *ex;
	int i = at, k, m, a;
	ext4_fsblk_t newblock, oldblock;
	__le32 border;
	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
	int err = 0;

	/* make decision: where to split? */
	/* FIXME: now decision is simplest: at current extent */

	/* if current leaf will be split, then we should use
	 * border from split point */
	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
		return -EIO;
	}
	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
		border = path[depth].p_ext[1].ee_block;
		ext_debug("leaf will be split."
				" next leaf starts at %d\n",
				  le32_to_cpu(border));
	} else {
		border = newext->ee_block;
		ext_debug("leaf will be added."
				" next leaf starts at %d\n",
				le32_to_cpu(border));
	}

	/*
	 * If error occurs, then we break processing
	 * and mark filesystem read-only. index won't
	 * be inserted and tree will be in consistent
	 * state. Next mount will repair buffers too.
	 */

	/*
	 * Get array to track all allocated blocks.
	 * We need this to handle errors and free blocks
	 * upon them.
	 */
	ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
	if (!ablocks)
		return -ENOMEM;

	/* allocate all needed blocks */
	ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
	for (a = 0; a < depth - at; a++) {
		newblock = ext4_ext_new_meta_block(handle, inode, path,
						   newext, &err);
		if (newblock == 0)
			goto cleanup;
		ablocks[a] = newblock;
	}

	/* initialize new leaf */
	newblock = ablocks[--a];
	if (unlikely(newblock == 0)) {
		EXT4_ERROR_INODE(inode, "newblock == 0!");
		err = -EIO;
		goto cleanup;
	}
	bh = sb_getblk(inode->i_sb, newblock);
	if (!bh) {
		err = -EIO;
		goto cleanup;
	}
	lock_buffer(bh);

	err = ext4_journal_get_create_access(handle, bh);
	if (err)
		goto cleanup;

	neh = ext_block_hdr(bh);
	neh->eh_entries = 0;
	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
	neh->eh_magic = EXT4_EXT_MAGIC;
	neh->eh_depth = 0;
	ex = EXT_FIRST_EXTENT(neh);

	/* move remainder of path[depth] to the new leaf */
	if (unlikely(path[depth].p_hdr->eh_entries !=
		     path[depth].p_hdr->eh_max)) {
		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
				 path[depth].p_hdr->eh_entries,
				 path[depth].p_hdr->eh_max);
		err = -EIO;
		goto cleanup;
	}
	/* start copy from next extent */
	/* TODO: we could do it by single memmove */
	m = 0;
	path[depth].p_ext++;
	while (path[depth].p_ext <=
			EXT_MAX_EXTENT(path[depth].p_hdr)) {
		ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
				le32_to_cpu(path[depth].p_ext->ee_block),
				ext4_ext_pblock(path[depth].p_ext),
				ext4_ext_is_uninitialized(path[depth].p_ext),
				ext4_ext_get_actual_len(path[depth].p_ext),
				newblock);
		/*memmove(ex++, path[depth].p_ext++,
				sizeof(struct ext4_extent));
		neh->eh_entries++;*/
		path[depth].p_ext++;
		m++;
	}
	if (m) {
		memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
		le16_add_cpu(&neh->eh_entries, m);
	}

	set_buffer_uptodate(bh);
	unlock_buffer(bh);

	err = ext4_handle_dirty_metadata(handle, inode, bh);
	if (err)
		goto cleanup;
	brelse(bh);
	bh = NULL;

	/* correct old leaf */
	if (m) {
		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			goto cleanup;
		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
		err = ext4_ext_dirty(handle, inode, path + depth);
		if (err)
			goto cleanup;

	}

	/* create intermediate indexes */
	k = depth - at - 1;
	if (unlikely(k < 0)) {
		EXT4_ERROR_INODE(inode, "k %d < 0!", k);
		err = -EIO;
		goto cleanup;
	}
	if (k)
		ext_debug("create %d intermediate indices\n", k);
	/* insert new index into current index block */
	/* current depth stored in i var */
	i = depth - 1;
	while (k--) {
		oldblock = newblock;
		newblock = ablocks[--a];
		bh = sb_getblk(inode->i_sb, newblock);
		if (!bh) {
			err = -EIO;
			goto cleanup;
		}
		lock_buffer(bh);

		err = ext4_journal_get_create_access(handle, bh);
		if (err)
			goto cleanup;

		neh = ext_block_hdr(bh);
		neh->eh_entries = cpu_to_le16(1);
		neh->eh_magic = EXT4_EXT_MAGIC;
		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
		neh->eh_depth = cpu_to_le16(depth - i);
		fidx = EXT_FIRST_INDEX(neh);
		fidx->ei_block = border;
		ext4_idx_store_pblock(fidx, oldblock);

		ext_debug("int.index at %d (block %llu): %u -> %llu\n",
				i, newblock, le32_to_cpu(border), oldblock);
		/* copy indexes */
		m = 0;
		path[i].p_idx++;

		ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
				EXT_MAX_INDEX(path[i].p_hdr));
		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
					EXT_LAST_INDEX(path[i].p_hdr))) {
			EXT4_ERROR_INODE(inode,
					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
					 le32_to_cpu(path[i].p_ext->ee_block));
			err = -EIO;
			goto cleanup;
		}
		while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
			ext_debug("%d: move %d:%llu in new index %llu\n", i,
					le32_to_cpu(path[i].p_idx->ei_block),
					ext4_idx_pblock(path[i].p_idx),
					newblock);
			/*memmove(++fidx, path[i].p_idx++,
					sizeof(struct ext4_extent_idx));
			neh->eh_entries++;
			BUG_ON(neh->eh_entries > neh->eh_max);*/
			path[i].p_idx++;
			m++;
		}
		if (m) {
			memmove(++fidx, path[i].p_idx - m,
				sizeof(struct ext4_extent_idx) * m);
			le16_add_cpu(&neh->eh_entries, m);
		}
		set_buffer_uptodate(bh);
		unlock_buffer(bh);

		err = ext4_handle_dirty_metadata(handle, inode, bh);
		if (err)
			goto cleanup;
		brelse(bh);
		bh = NULL;

		/* correct old index */
		if (m) {
			err = ext4_ext_get_access(handle, inode, path + i);
			if (err)
				goto cleanup;
			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
			err = ext4_ext_dirty(handle, inode, path + i);
			if (err)
				goto cleanup;
		}

		i--;
	}

	/* insert new index */
	err = ext4_ext_insert_index(handle, inode, path + at,
				    le32_to_cpu(border), newblock);

cleanup:
	if (bh) {
		if (buffer_locked(bh))
			unlock_buffer(bh);
		brelse(bh);
	}

	if (err) {
		/* free all allocated blocks in error case */
		for (i = 0; i < depth; i++) {
			if (!ablocks[i])
				continue;
			ext4_free_blocks(handle, inode, 0, ablocks[i], 1,
					 EXT4_FREE_BLOCKS_METADATA);
		}
	}
	kfree(ablocks);

	return err;
}

/*
 * ext4_ext_grow_indepth:
 * implements tree growing procedure:
 * - allocates new block
 * - moves top-level data (index block or leaf) into the new block
 * - initializes new top-level, creating index that points to the
 *   just created block
 */
static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
					struct ext4_ext_path *path,
					struct ext4_extent *newext)
{
	struct ext4_ext_path *curp = path;
	struct ext4_extent_header *neh;
	struct buffer_head *bh;
	ext4_fsblk_t newblock;
	int err = 0;

	newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
	if (newblock == 0)
		return err;

	bh = sb_getblk(inode->i_sb, newblock);
	if (!bh) {
		err = -EIO;
		ext4_std_error(inode->i_sb, err);
		return err;
	}
	lock_buffer(bh);

	err = ext4_journal_get_create_access(handle, bh);
	if (err) {
		unlock_buffer(bh);
		goto out;
	}

	/* move top-level index/leaf into new block */
	memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));

	/* set size of new block */
	neh = ext_block_hdr(bh);
	/* old root could have indexes or leaves
	 * so calculate e_max right way */
	if (ext_depth(inode))
		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
	else
		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
	neh->eh_magic = EXT4_EXT_MAGIC;
	set_buffer_uptodate(bh);
	unlock_buffer(bh);

	err = ext4_handle_dirty_metadata(handle, inode, bh);
	if (err)
		goto out;

	/* create index in new top-level index: num,max,pointer */
	err = ext4_ext_get_access(handle, inode, curp);
	if (err)
		goto out;

	curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
	curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
	curp->p_hdr->eh_entries = cpu_to_le16(1);
	curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);

	if (path[0].p_hdr->eh_depth)
		curp->p_idx->ei_block =
			EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
	else
		curp->p_idx->ei_block =
			EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
	ext4_idx_store_pblock(curp->p_idx, newblock);

	neh = ext_inode_hdr(inode);
	ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));

	neh->eh_depth = cpu_to_le16(path->p_depth + 1);
	err = ext4_ext_dirty(handle, inode, curp);
out:
	brelse(bh);

	return err;
}

/*
 * ext4_ext_create_new_leaf:
 * finds empty index and adds new leaf.
 * if no free index is found, then it requests in-depth growing.
 */
static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
					struct ext4_ext_path *path,
					struct ext4_extent *newext)
{
	struct ext4_ext_path *curp;
	int depth, i, err = 0;

repeat:
	i = depth = ext_depth(inode);

	/* walk up to the tree and look for free index entry */
	curp = path + depth;
	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
		i--;
		curp--;
	}

	/* we use already allocated block for index block,
	 * so subsequent data blocks should be contiguous */
	if (EXT_HAS_FREE_INDEX(curp)) {
		/* if we found index with free entry, then use that
		 * entry: create all needed subtree and add new leaf */
		err = ext4_ext_split(handle, inode, path, newext, i);
		if (err)
			goto out;

		/* refill path */
		ext4_ext_drop_refs(path);
		path = ext4_ext_find_extent(inode,
				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
				    path);
		if (IS_ERR(path))
			err = PTR_ERR(path);
	} else {
		/* tree is full, time to grow in depth */
		err = ext4_ext_grow_indepth(handle, inode, path, newext);
		if (err)
			goto out;

		/* refill path */
		ext4_ext_drop_refs(path);
		path = ext4_ext_find_extent(inode,
				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
				    path);
		if (IS_ERR(path)) {
			err = PTR_ERR(path);
			goto out;
		}

		/*
		 * only first (depth 0 -> 1) produces free space;
		 * in all other cases we have to split the grown tree
		 */
		depth = ext_depth(inode);
		if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
			/* now we need to split */
			goto repeat;
		}
	}

out:
	return err;
}

/*
 * search the closest allocated block to the left for *logical
 * and returns it at @logical + it's physical address at @phys
 * if *logical is the smallest allocated block, the function
 * returns 0 at @phys
 * return value contains 0 (success) or error code
 */
static int ext4_ext_search_left(struct inode *inode,
				struct ext4_ext_path *path,
				ext4_lblk_t *logical, ext4_fsblk_t *phys)
{
	struct ext4_extent_idx *ix;
	struct ext4_extent *ex;
	int depth, ee_len;

	if (unlikely(path == NULL)) {
		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
		return -EIO;
	}
	depth = path->p_depth;
	*phys = 0;

	if (depth == 0 && path->p_ext == NULL)
		return 0;

	/* usually extent in the path covers blocks smaller
	 * then *logical, but it can be that extent is the
	 * first one in the file */

	ex = path[depth].p_ext;
	ee_len = ext4_ext_get_actual_len(ex);
	if (*logical < le32_to_cpu(ex->ee_block)) {
		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
			EXT4_ERROR_INODE(inode,
					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
					 *logical, le32_to_cpu(ex->ee_block));
			return -EIO;
		}
		while (--depth >= 0) {
			ix = path[depth].p_idx;
			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
				EXT4_ERROR_INODE(inode,
				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
				  ix != NULL ? ix->ei_block : 0,
				  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
				    EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
				  depth);
				return -EIO;
			}
		}
		return 0;
	}

	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
		EXT4_ERROR_INODE(inode,
				 "logical %d < ee_block %d + ee_len %d!",
				 *logical, le32_to_cpu(ex->ee_block), ee_len);
		return -EIO;
	}

	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
	*phys = ext4_ext_pblock(ex) + ee_len - 1;
	return 0;
}

/*
 * search the closest allocated block to the right for *logical
 * and returns it at @logical + it's physical address at @phys
 * if *logical is the smallest allocated block, the function
 * returns 0 at @phys
 * return value contains 0 (success) or error code
 */
static int ext4_ext_search_right(struct inode *inode,
				 struct ext4_ext_path *path,
				 ext4_lblk_t *logical, ext4_fsblk_t *phys)
{
	struct buffer_head *bh = NULL;
	struct ext4_extent_header *eh;
	struct ext4_extent_idx *ix;
	struct ext4_extent *ex;
	ext4_fsblk_t block;
	int depth;	/* Note, NOT eh_depth; depth from top of tree */
	int ee_len;

	if (unlikely(path == NULL)) {
		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
		return -EIO;
	}
	depth = path->p_depth;
	*phys = 0;

	if (depth == 0 && path->p_ext == NULL)
		return 0;

	/* usually extent in the path covers blocks smaller
	 * then *logical, but it can be that extent is the
	 * first one in the file */

	ex = path[depth].p_ext;
	ee_len = ext4_ext_get_actual_len(ex);
	if (*logical < le32_to_cpu(ex->ee_block)) {
		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
			EXT4_ERROR_INODE(inode,
					 "first_extent(path[%d].p_hdr) != ex",
					 depth);
			return -EIO;
		}
		while (--depth >= 0) {
			ix = path[depth].p_idx;
			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
				EXT4_ERROR_INODE(inode,
						 "ix != EXT_FIRST_INDEX *logical %d!",
						 *logical);
				return -EIO;
			}
		}
		*logical = le32_to_cpu(ex->ee_block);
		*phys = ext4_ext_pblock(ex);
		return 0;
	}

	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
		EXT4_ERROR_INODE(inode,
				 "logical %d < ee_block %d + ee_len %d!",
				 *logical, le32_to_cpu(ex->ee_block), ee_len);
		return -EIO;
	}

	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
		/* next allocated block in this leaf */
		ex++;
		*logical = le32_to_cpu(ex->ee_block);
		*phys = ext4_ext_pblock(ex);
		return 0;
	}

	/* go up and search for index to the right */
	while (--depth >= 0) {
		ix = path[depth].p_idx;
		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
			goto got_index;
	}

	/* we've gone up to the root and found no index to the right */
	return 0;

got_index:
	/* we've found index to the right, let's
	 * follow it and find the closest allocated
	 * block to the right */
	ix++;
	block = ext4_idx_pblock(ix);
	while (++depth < path->p_depth) {
		bh = sb_bread(inode->i_sb, block);
		if (bh == NULL)
			return -EIO;
		eh = ext_block_hdr(bh);
		/* subtract from p_depth to get proper eh_depth */
		if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
			put_bh(bh);
			return -EIO;
		}
		ix = EXT_FIRST_INDEX(eh);
		block = ext4_idx_pblock(ix);
		put_bh(bh);
	}

	bh = sb_bread(inode->i_sb, block);
	if (bh == NULL)
		return -EIO;
	eh = ext_block_hdr(bh);
	if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
		put_bh(bh);
		return -EIO;
	}
	ex = EXT_FIRST_EXTENT(eh);
	*logical = le32_to_cpu(ex->ee_block);
	*phys = ext4_ext_pblock(ex);
	put_bh(bh);
	return 0;
}

/*
 * ext4_ext_next_allocated_block:
 * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
 * NOTE: it considers block number from index entry as
 * allocated block. Thus, index entries have to be consistent
 * with leaves.
 */
static ext4_lblk_t
ext4_ext_next_allocated_block(struct ext4_ext_path *path)
{
	int depth;

	BUG_ON(path == NULL);
	depth = path->p_depth;

	if (depth == 0 && path->p_ext == NULL)
		return EXT_MAX_BLOCK;

	while (depth >= 0) {
		if (depth == path->p_depth) {
			/* leaf */
			if (path[depth].p_ext !=
					EXT_LAST_EXTENT(path[depth].p_hdr))
			  return le32_to_cpu(path[depth].p_ext[1].ee_block);
		} else {
			/* index */
			if (path[depth].p_idx !=
					EXT_LAST_INDEX(path[depth].p_hdr))
			  return le32_to_cpu(path[depth].p_idx[1].ei_block);
		}
		depth--;
	}

	return EXT_MAX_BLOCK;
}

/*
 * ext4_ext_next_leaf_block:
 * returns first allocated block from next leaf or EXT_MAX_BLOCK
 */
static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
					struct ext4_ext_path *path)
{
	int depth;

	BUG_ON(path == NULL);
	depth = path->p_depth;

	/* zero-tree has no leaf blocks at all */
	if (depth == 0)
		return EXT_MAX_BLOCK;

	/* go to index block */
	depth--;

	while (depth >= 0) {
		if (path[depth].p_idx !=
				EXT_LAST_INDEX(path[depth].p_hdr))
			return (ext4_lblk_t)
				le32_to_cpu(path[depth].p_idx[1].ei_block);
		depth--;
	}

	return EXT_MAX_BLOCK;
}

/*
 * ext4_ext_correct_indexes:
 * if leaf gets modified and modified extent is first in the leaf,
 * then we have to correct all indexes above.
 * TODO: do we need to correct tree in all cases?
 */
static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
				struct ext4_ext_path *path)
{
	struct ext4_extent_header *eh;
	int depth = ext_depth(inode);
	struct ext4_extent *ex;
	__le32 border;
	int k, err = 0;

	eh = path[depth].p_hdr;
	ex = path[depth].p_ext;

	if (unlikely(ex == NULL || eh == NULL)) {
		EXT4_ERROR_INODE(inode,
				 "ex %p == NULL or eh %p == NULL", ex, eh);
		return -EIO;
	}

	if (depth == 0) {
		/* there is no tree at all */
		return 0;
	}

	if (ex != EXT_FIRST_EXTENT(eh)) {
		/* we correct tree if first leaf got modified only */
		return 0;
	}

	/*
	 * TODO: we need correction if border is smaller than current one
	 */
	k = depth - 1;
	border = path[depth].p_ext->ee_block;
	err = ext4_ext_get_access(handle, inode, path + k);
	if (err)
		return err;
	path[k].p_idx->ei_block = border;
	err = ext4_ext_dirty(handle, inode, path + k);
	if (err)
		return err;

	while (k--) {
		/* change all left-side indexes */
		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
			break;
		err = ext4_ext_get_access(handle, inode, path + k);
		if (err)
			break;
		path[k].p_idx->ei_block = border;
		err = ext4_ext_dirty(handle, inode, path + k);
		if (err)
			break;
	}

	return err;
}

int
ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
				struct ext4_extent *ex2)
{
	unsigned short ext1_ee_len, ext2_ee_len, max_len;

	/*
	 * Make sure that either both extents are uninitialized, or
	 * both are _not_.
	 */
	if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
		return 0;

	if (ext4_ext_is_uninitialized(ex1))
		max_len = EXT_UNINIT_MAX_LEN;
	else
		max_len = EXT_INIT_MAX_LEN;

	ext1_ee_len = ext4_ext_get_actual_len(ex1);
	ext2_ee_len = ext4_ext_get_actual_len(ex2);

	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
			le32_to_cpu(ex2->ee_block))
		return 0;

	/*
	 * To allow future support for preallocated extents to be added
	 * as an RO_COMPAT feature, refuse to merge to extents if
	 * this can result in the top bit of ee_len being set.
	 */
	if (ext1_ee_len + ext2_ee_len > max_len)
		return 0;
#ifdef AGGRESSIVE_TEST
	if (ext1_ee_len >= 4)
		return 0;
#endif

	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
		return 1;
	return 0;
}

/*
 * This function tries to merge the "ex" extent to the next extent in the tree.
 * It always tries to merge towards right. If you want to merge towards
 * left, pass "ex - 1" as argument instead of "ex".
 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
 * 1 if they got merged.
 */
static int ext4_ext_try_to_merge(struct inode *inode,
				 struct ext4_ext_path *path,
				 struct ext4_extent *ex)
{
	struct ext4_extent_header *eh;
	unsigned int depth, len;
	int merge_done = 0;
	int uninitialized = 0;

	depth = ext_depth(inode);
	BUG_ON(path[depth].p_hdr == NULL);
	eh = path[depth].p_hdr;

	while (ex < EXT_LAST_EXTENT(eh)) {
		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
			break;
		/* merge with next extent! */
		if (ext4_ext_is_uninitialized(ex))
			uninitialized = 1;
		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
				+ ext4_ext_get_actual_len(ex + 1));
		if (uninitialized)
			ext4_ext_mark_uninitialized(ex);

		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
			len = (EXT_LAST_EXTENT(eh) - ex - 1)
				* sizeof(struct ext4_extent);
			memmove(ex + 1, ex + 2, len);
		}
		le16_add_cpu(&eh->eh_entries, -1);
		merge_done = 1;
		WARN_ON(eh->eh_entries == 0);
		if (!eh->eh_entries)
			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
	}

	return merge_done;
}

/*
 * check if a portion of the "newext" extent overlaps with an
 * existing extent.
 *
 * If there is an overlap discovered, it updates the length of the newext
 * such that there will be no overlap, and then returns 1.
 * If there is no overlap found, it returns 0.
 */
static unsigned int ext4_ext_check_overlap(struct inode *inode,
					   struct ext4_extent *newext,
					   struct ext4_ext_path *path)
{
	ext4_lblk_t b1, b2;
	unsigned int depth, len1;
	unsigned int ret = 0;

	b1 = le32_to_cpu(newext->ee_block);
	len1 = ext4_ext_get_actual_len(newext);
	depth = ext_depth(inode);
	if (!path[depth].p_ext)
		goto out;
	b2 = le32_to_cpu(path[depth].p_ext->ee_block);

	/*
	 * get the next allocated block if the extent in the path
	 * is before the requested block(s)
	 */
	if (b2 < b1) {
		b2 = ext4_ext_next_allocated_block(path);
		if (b2 == EXT_MAX_BLOCK)
			goto out;
	}

	/* check for wrap through zero on extent logical start block*/
	if (b1 + len1 < b1) {
		len1 = EXT_MAX_BLOCK - b1;
		newext->ee_len = cpu_to_le16(len1);
		ret = 1;
	}

	/* check for overlap */
	if (b1 + len1 > b2) {
		newext->ee_len = cpu_to_le16(b2 - b1);
		ret = 1;
	}
out:
	return ret;
}

/*
 * ext4_ext_insert_extent:
 * tries to merge requsted extent into the existing extent or
 * inserts requested extent as new one into the tree,
 * creating new leaf in the no-space case.
 */
int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
				struct ext4_ext_path *path,
				struct ext4_extent *newext, int flag)
{
	struct ext4_extent_header *eh;
	struct ext4_extent *ex, *fex;
	struct ext4_extent *nearex; /* nearest extent */
	struct ext4_ext_path *npath = NULL;
	int depth, len, err;
	ext4_lblk_t next;
	unsigned uninitialized = 0;

	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
		return -EIO;
	}
	depth = ext_depth(inode);
	ex = path[depth].p_ext;
	if (unlikely(path[depth].p_hdr == NULL)) {
		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
		return -EIO;
	}

	/* try to insert block into found extent and return */
	if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
		&& ext4_can_extents_be_merged(inode, ex, newext)) {
		ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
			  ext4_ext_is_uninitialized(newext),
			  ext4_ext_get_actual_len(newext),
			  le32_to_cpu(ex->ee_block),
			  ext4_ext_is_uninitialized(ex),
			  ext4_ext_get_actual_len(ex),
			  ext4_ext_pblock(ex));
		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			return err;

		/*
		 * ext4_can_extents_be_merged should have checked that either
		 * both extents are uninitialized, or both aren't. Thus we
		 * need to check only one of them here.
		 */
		if (ext4_ext_is_uninitialized(ex))
			uninitialized = 1;
		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
					+ ext4_ext_get_actual_len(newext));
		if (uninitialized)
			ext4_ext_mark_uninitialized(ex);
		eh = path[depth].p_hdr;
		nearex = ex;
		goto merge;
	}

repeat:
	depth = ext_depth(inode);
	eh = path[depth].p_hdr;
	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
		goto has_space;

	/* probably next leaf has space for us? */
	fex = EXT_LAST_EXTENT(eh);
	next = ext4_ext_next_leaf_block(inode, path);
	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
	    && next != EXT_MAX_BLOCK) {
		ext_debug("next leaf block - %d\n", next);
		BUG_ON(npath != NULL);
		npath = ext4_ext_find_extent(inode, next, NULL);
		if (IS_ERR(npath))
			return PTR_ERR(npath);
		BUG_ON(npath->p_depth != path->p_depth);
		eh = npath[depth].p_hdr;
		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
			ext_debug("next leaf isnt full(%d)\n",
				  le16_to_cpu(eh->eh_entries));
			path = npath;
			goto repeat;
		}
		ext_debug("next leaf has no free space(%d,%d)\n",
			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
	}

	/*
	 * There is no free space in the found leaf.
	 * We're gonna add a new leaf in the tree.
	 */
	err = ext4_ext_create_new_leaf(handle, inode, path, newext);
	if (err)
		goto cleanup;
	depth = ext_depth(inode);
	eh = path[depth].p_hdr;

has_space:
	nearex = path[depth].p_ext;

	err = ext4_ext_get_access(handle, inode, path + depth);
	if (err)
		goto cleanup;

	if (!nearex) {
		/* there is no extent in this leaf, create first one */
		ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
				le32_to_cpu(newext->ee_block),
				ext4_ext_pblock(newext),
				ext4_ext_is_uninitialized(newext),
				ext4_ext_get_actual_len(newext));
		path[depth].p_ext = EXT_FIRST_EXTENT(eh);
	} else if (le32_to_cpu(newext->ee_block)
			   > le32_to_cpu(nearex->ee_block)) {
/*		BUG_ON(newext->ee_block == nearex->ee_block); */
		if (nearex != EXT_LAST_EXTENT(eh)) {
			len = EXT_MAX_EXTENT(eh) - nearex;
			len = (len - 1) * sizeof(struct ext4_extent);
			len = len < 0 ? 0 : len;
			ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
					"move %d from 0x%p to 0x%p\n",
					le32_to_cpu(newext->ee_block),
					ext4_ext_pblock(newext),
					ext4_ext_is_uninitialized(newext),
					ext4_ext_get_actual_len(newext),
					nearex, len, nearex + 1, nearex + 2);
			memmove(nearex + 2, nearex + 1, len);
		}
		path[depth].p_ext = nearex + 1;
	} else {
		BUG_ON(newext->ee_block == nearex->ee_block);
		len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
		len = len < 0 ? 0 : len;
		ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
				"move %d from 0x%p to 0x%p\n",
				le32_to_cpu(newext->ee_block),
				ext4_ext_pblock(newext),
				ext4_ext_is_uninitialized(newext),
				ext4_ext_get_actual_len(newext),
				nearex, len, nearex + 1, nearex + 2);
		memmove(nearex + 1, nearex, len);
		path[depth].p_ext = nearex;
	}

	le16_add_cpu(&eh->eh_entries, 1);
	nearex = path[depth].p_ext;
	nearex->ee_block = newext->ee_block;
	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
	nearex->ee_len = newext->ee_len;

merge:
	/* try to merge extents to the right */
	if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
		ext4_ext_try_to_merge(inode, path, nearex);

	/* try to merge extents to the left */

	/* time to correct all indexes above */
	err = ext4_ext_correct_indexes(handle, inode, path);
	if (err)
		goto cleanup;

	err = ext4_ext_dirty(handle, inode, path + depth);

cleanup:
	if (npath) {
		ext4_ext_drop_refs(npath);
		kfree(npath);
	}
	ext4_ext_invalidate_cache(inode);
	return err;
}

static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
			       ext4_lblk_t num, ext_prepare_callback func,
			       void *cbdata)
{
	struct ext4_ext_path *path = NULL;
	struct ext4_ext_cache cbex;
	struct ext4_extent *ex;
	ext4_lblk_t next, start = 0, end = 0;
	ext4_lblk_t last = block + num;
	int depth, exists, err = 0;

	BUG_ON(func == NULL);
	BUG_ON(inode == NULL);

	while (block < last && block != EXT_MAX_BLOCK) {
		num = last - block;
		/* find extent for this block */
		down_read(&EXT4_I(inode)->i_data_sem);
		path = ext4_ext_find_extent(inode, block, path);
		up_read(&EXT4_I(inode)->i_data_sem);
		if (IS_ERR(path)) {
			err = PTR_ERR(path);
			path = NULL;
			break;
		}

		depth = ext_depth(inode);
		if (unlikely(path[depth].p_hdr == NULL)) {
			EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
			err = -EIO;
			break;
		}
		ex = path[depth].p_ext;
		next = ext4_ext_next_allocated_block(path);

		exists = 0;
		if (!ex) {
			/* there is no extent yet, so try to allocate
			 * all requested space */
			start = block;
			end = block + num;
		} else if (le32_to_cpu(ex->ee_block) > block) {
			/* need to allocate space before found extent */
			start = block;
			end = le32_to_cpu(ex->ee_block);
			if (block + num < end)
				end = block + num;
		} else if (block >= le32_to_cpu(ex->ee_block)
					+ ext4_ext_get_actual_len(ex)) {
			/* need to allocate space after found extent */
			start = block;
			end = block + num;
			if (end >= next)
				end = next;
		} else if (block >= le32_to_cpu(ex->ee_block)) {
			/*
			 * some part of requested space is covered
			 * by found extent
			 */
			start = block;
			end = le32_to_cpu(ex->ee_block)
				+ ext4_ext_get_actual_len(ex);
			if (block + num < end)
				end = block + num;
			exists = 1;
		} else {
			BUG();
		}
		BUG_ON(end <= start);

		if (!exists) {
			cbex.ec_block = start;
			cbex.ec_len = end - start;
			cbex.ec_start = 0;
		} else {
			cbex.ec_block = le32_to_cpu(ex->ee_block);
			cbex.ec_len = ext4_ext_get_actual_len(ex);
			cbex.ec_start = ext4_ext_pblock(ex);
		}

		if (unlikely(cbex.ec_len == 0)) {
			EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
			err = -EIO;
			break;
		}
		err = func(inode, path, &cbex, ex, cbdata);
		ext4_ext_drop_refs(path);

		if (err < 0)
			break;

		if (err == EXT_REPEAT)
			continue;
		else if (err == EXT_BREAK) {
			err = 0;
			break;
		}

		if (ext_depth(inode) != depth) {
			/* depth was changed. we have to realloc path */
			kfree(path);
			path = NULL;
		}

		block = cbex.ec_block + cbex.ec_len;
	}

	if (path) {
		ext4_ext_drop_refs(path);
		kfree(path);
	}

	return err;
}

static void
ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
			__u32 len, ext4_fsblk_t start)
{
	struct ext4_ext_cache *cex;
	BUG_ON(len == 0);
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	cex = &EXT4_I(inode)->i_cached_extent;
	cex->ec_block = block;
	cex->ec_len = len;
	cex->ec_start = start;
	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}

/*
 * ext4_ext_put_gap_in_cache:
 * calculate boundaries of the gap that the requested block fits into
 * and cache this gap
 */
static void
ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
				ext4_lblk_t block)
{
	int depth = ext_depth(inode);
	unsigned long len;
	ext4_lblk_t lblock;
	struct ext4_extent *ex;

	ex = path[depth].p_ext;
	if (ex == NULL) {
		/* there is no extent yet, so gap is [0;-] */
		lblock = 0;
		len = EXT_MAX_BLOCK;
		ext_debug("cache gap(whole file):");
	} else if (block < le32_to_cpu(ex->ee_block)) {
		lblock = block;
		len = le32_to_cpu(ex->ee_block) - block;
		ext_debug("cache gap(before): %u [%u:%u]",
				block,
				le32_to_cpu(ex->ee_block),
				 ext4_ext_get_actual_len(ex));
	} else if (block >= le32_to_cpu(ex->ee_block)
			+ ext4_ext_get_actual_len(ex)) {
		ext4_lblk_t next;
		lblock = le32_to_cpu(ex->ee_block)
			+ ext4_ext_get_actual_len(ex);

		next = ext4_ext_next_allocated_block(path);
		ext_debug("cache gap(after): [%u:%u] %u",
				le32_to_cpu(ex->ee_block),
				ext4_ext_get_actual_len(ex),
				block);
		BUG_ON(next == lblock);
		len = next - lblock;
	} else {
		lblock = len = 0;
		BUG();
	}

	ext_debug(" -> %u:%lu\n", lblock, len);
	ext4_ext_put_in_cache(inode, lblock, len, 0);
}

/*
 * Return 0 if cache is invalid; 1 if the cache is valid
 */
static int
ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
			struct ext4_extent *ex)
{
	struct ext4_ext_cache *cex;
	int ret = 0;

	/*
	 * We borrow i_block_reservation_lock to protect i_cached_extent
	 */
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	cex = &EXT4_I(inode)->i_cached_extent;

	/* has cache valid data? */
	if (cex->ec_len == 0)
		goto errout;

	if (in_range(block, cex->ec_block, cex->ec_len)) {
		ex->ee_block = cpu_to_le32(cex->ec_block);
		ext4_ext_store_pblock(ex, cex->ec_start);
		ex->ee_len = cpu_to_le16(cex->ec_len);
		ext_debug("%u cached by %u:%u:%llu\n",
				block,
				cex->ec_block, cex->ec_len, cex->ec_start);
		ret = 1;
	}
errout:
	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
	return ret;
}

/*
 * ext4_ext_rm_idx:
 * removes index from the index block.
 * It's used in truncate case only, thus all requests are for
 * last index in the block only.
 */
static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
			struct ext4_ext_path *path)
{
	int err;
	ext4_fsblk_t leaf;

	/* free index block */
	path--;
	leaf = ext4_idx_pblock(path->p_idx);
	if (unlikely(path->p_hdr->eh_entries == 0)) {
		EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
		return -EIO;
	}
	err = ext4_ext_get_access(handle, inode, path);
	if (err)
		return err;
	le16_add_cpu(&path->p_hdr->eh_entries, -1);
	err = ext4_ext_dirty(handle, inode, path);
	if (err)
		return err;
	ext_debug("index is empty, remove it, free block %llu\n", leaf);
	ext4_free_blocks(handle, inode, 0, leaf, 1,
			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
	return err;
}

/*
 * ext4_ext_calc_credits_for_single_extent:
 * This routine returns max. credits that needed to insert an extent
 * to the extent tree.
 * When pass the actual path, the caller should calculate credits
 * under i_data_sem.
 */
int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
						struct ext4_ext_path *path)
{
	if (path) {
		int depth = ext_depth(inode);
		int ret = 0;

		/* probably there is space in leaf? */
		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
				< le16_to_cpu(path[depth].p_hdr->eh_max)) {

			/*
			 *  There are some space in the leaf tree, no
			 *  need to account for leaf block credit
			 *
			 *  bitmaps and block group descriptor blocks
			 *  and other metadat blocks still need to be
			 *  accounted.
			 */
			/* 1 bitmap, 1 block group descriptor */
			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
			return ret;
		}
	}

	return ext4_chunk_trans_blocks(inode, nrblocks);
}

/*
 * How many index/leaf blocks need to change/allocate to modify nrblocks?
 *
 * if nrblocks are fit in a single extent (chunk flag is 1), then
 * in the worse case, each tree level index/leaf need to be changed
 * if the tree split due to insert a new extent, then the old tree
 * index/leaf need to be updated too
 *
 * If the nrblocks are discontiguous, they could cause
 * the whole tree split more than once, but this is really rare.
 */
int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
	int index;
	int depth = ext_depth(inode);

	if (chunk)
		index = depth * 2;
	else
		index = depth * 3;

	return index;
}

static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
				struct ext4_extent *ex,
				ext4_lblk_t from, ext4_lblk_t to)
{
	unsigned short ee_len =  ext4_ext_get_actual_len(ex);
	int flags = EXT4_FREE_BLOCKS_FORGET;

	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
		flags |= EXT4_FREE_BLOCKS_METADATA;
#ifdef EXTENTS_STATS
	{
		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
		spin_lock(&sbi->s_ext_stats_lock);
		sbi->s_ext_blocks += ee_len;
		sbi->s_ext_extents++;
		if (ee_len < sbi->s_ext_min)
			sbi->s_ext_min = ee_len;
		if (ee_len > sbi->s_ext_max)
			sbi->s_ext_max = ee_len;
		if (ext_depth(inode) > sbi->s_depth_max)
			sbi->s_depth_max = ext_depth(inode);
		spin_unlock(&sbi->s_ext_stats_lock);
	}
#endif
	if (from >= le32_to_cpu(ex->ee_block)
	    && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
		/* tail removal */
		ext4_lblk_t num;
		ext4_fsblk_t start;

		num = le32_to_cpu(ex->ee_block) + ee_len - from;
		start = ext4_ext_pblock(ex) + ee_len - num;
		ext_debug("free last %u blocks starting %llu\n", num, start);
		ext4_free_blocks(handle, inode, 0, start, num, flags);
	} else if (from == le32_to_cpu(ex->ee_block)
		   && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
		printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
			from, to, le32_to_cpu(ex->ee_block), ee_len);
	} else {
		printk(KERN_INFO "strange request: removal(2) "
				"%u-%u from %u:%u\n",
				from, to, le32_to_cpu(ex->ee_block), ee_len);
	}
	return 0;
}

static int
ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
		struct ext4_ext_path *path, ext4_lblk_t start)
{
	int err = 0, correct_index = 0;
	int depth = ext_depth(inode), credits;
	struct ext4_extent_header *eh;
	ext4_lblk_t a, b, block;
	unsigned num;
	ext4_lblk_t ex_ee_block;
	unsigned short ex_ee_len;
	unsigned uninitialized = 0;
	struct ext4_extent *ex;

	/* the header must be checked already in ext4_ext_remove_space() */
	ext_debug("truncate since %u in leaf\n", start);
	if (!path[depth].p_hdr)
		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
	eh = path[depth].p_hdr;
	if (unlikely(path[depth].p_hdr == NULL)) {
		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
		return -EIO;
	}
	/* find where to start removing */
	ex = EXT_LAST_EXTENT(eh);

	ex_ee_block = le32_to_cpu(ex->ee_block);
	ex_ee_len = ext4_ext_get_actual_len(ex);

	while (ex >= EXT_FIRST_EXTENT(eh) &&
			ex_ee_block + ex_ee_len > start) {

		if (ext4_ext_is_uninitialized(ex))
			uninitialized = 1;
		else
			uninitialized = 0;

		ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
			 uninitialized, ex_ee_len);
		path[depth].p_ext = ex;

		a = ex_ee_block > start ? ex_ee_block : start;
		b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
			ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;

		ext_debug("  border %u:%u\n", a, b);

		if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
			block = 0;
			num = 0;
			BUG();
		} else if (a != ex_ee_block) {
			/* remove tail of the extent */
			block = ex_ee_block;
			num = a - block;
		} else if (b != ex_ee_block + ex_ee_len - 1) {
			/* remove head of the extent */
			block = a;
			num = b - a;
			/* there is no "make a hole" API yet */
			BUG();
		} else {
			/* remove whole extent: excellent! */
			block = ex_ee_block;
			num = 0;
			BUG_ON(a != ex_ee_block);
			BUG_ON(b != ex_ee_block + ex_ee_len - 1);
		}

		/*
		 * 3 for leaf, sb, and inode plus 2 (bmap and group
		 * descriptor) for each block group; assume two block
		 * groups plus ex_ee_len/blocks_per_block_group for
		 * the worst case
		 */
		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
		if (ex == EXT_FIRST_EXTENT(eh)) {
			correct_index = 1;
			credits += (ext_depth(inode)) + 1;
		}
		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);

		err = ext4_ext_truncate_extend_restart(handle, inode, credits);
		if (err)
			goto out;

		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			goto out;

		err = ext4_remove_blocks(handle, inode, ex, a, b);
		if (err)
			goto out;

		if (num == 0) {
			/* this extent is removed; mark slot entirely unused */
			ext4_ext_store_pblock(ex, 0);
			le16_add_cpu(&eh->eh_entries, -1);
		}

		ex->ee_block = cpu_to_le32(block);
		ex->ee_len = cpu_to_le16(num);
		/*
		 * Do not mark uninitialized if all the blocks in the
		 * extent have been removed.
		 */
		if (uninitialized && num)
			ext4_ext_mark_uninitialized(ex);

		err = ext4_ext_dirty(handle, inode, path + depth);
		if (err)
			goto out;

		ext_debug("new extent: %u:%u:%llu\n", block, num,
				ext4_ext_pblock(ex));
		ex--;
		ex_ee_block = le32_to_cpu(ex->ee_block);
		ex_ee_len = ext4_ext_get_actual_len(ex);
	}

	if (correct_index && eh->eh_entries)
		err = ext4_ext_correct_indexes(handle, inode, path);

	/* if this leaf is free, then we should
	 * remove it from index block above */
	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
		err = ext4_ext_rm_idx(handle, inode, path + depth);

out:
	return err;
}

/*
 * ext4_ext_more_to_rm:
 * returns 1 if current index has to be freed (even partial)
 */
static int
ext4_ext_more_to_rm(struct ext4_ext_path *path)
{
	BUG_ON(path->p_idx == NULL);

	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
		return 0;

	/*
	 * if truncate on deeper level happened, it wasn't partial,
	 * so we have to consider current index for truncation
	 */
	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
		return 0;
	return 1;
}

static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
{
	struct super_block *sb = inode->i_sb;
	int depth = ext_depth(inode);
	struct ext4_ext_path *path;
	handle_t *handle;
	int i, err;

	ext_debug("truncate since %u\n", start);

	/* probably first extent we're gonna free will be last in block */
	handle = ext4_journal_start(inode, depth + 1);
	if (IS_ERR(handle))
		return PTR_ERR(handle);

again:
	ext4_ext_invalidate_cache(inode);

	/*
	 * We start scanning from right side, freeing all the blocks
	 * after i_size and walking into the tree depth-wise.
	 */
	depth = ext_depth(inode);
	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
	if (path == NULL) {
		ext4_journal_stop(handle);
		return -ENOMEM;
	}
	path[0].p_depth = depth;
	path[0].p_hdr = ext_inode_hdr(inode);
	if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
		err = -EIO;
		goto out;
	}
	i = err = 0;

	while (i >= 0 && err == 0) {
		if (i == depth) {
			/* this is leaf block */
			err = ext4_ext_rm_leaf(handle, inode, path, start);
			/* root level has p_bh == NULL, brelse() eats this */
			brelse(path[i].p_bh);
			path[i].p_bh = NULL;
			i--;
			continue;
		}

		/* this is index block */
		if (!path[i].p_hdr) {
			ext_debug("initialize header\n");
			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
		}

		if (!path[i].p_idx) {
			/* this level hasn't been touched yet */
			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
			ext_debug("init index ptr: hdr 0x%p, num %d\n",
				  path[i].p_hdr,
				  le16_to_cpu(path[i].p_hdr->eh_entries));
		} else {
			/* we were already here, see at next index */
			path[i].p_idx--;
		}

		ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
				i, EXT_FIRST_INDEX(path[i].p_hdr),
				path[i].p_idx);
		if (ext4_ext_more_to_rm(path + i)) {
			struct buffer_head *bh;
			/* go to the next level */
			ext_debug("move to level %d (block %llu)\n",
				  i + 1, ext4_idx_pblock(path[i].p_idx));
			memset(path + i + 1, 0, sizeof(*path));
			bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
			if (!bh) {
				/* should we reset i_size? */
				err = -EIO;
				break;
			}
			if (WARN_ON(i + 1 > depth)) {
				err = -EIO;
				break;
			}
			if (ext4_ext_check(inode, ext_block_hdr(bh),
							depth - i - 1)) {
				err = -EIO;
				break;
			}
			path[i + 1].p_bh = bh;

			/* save actual number of indexes since this
			 * number is changed at the next iteration */
			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
			i++;
		} else {
			/* we finished processing this index, go up */
			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
				/* index is empty, remove it;
				 * handle must be already prepared by the
				 * truncatei_leaf() */
				err = ext4_ext_rm_idx(handle, inode, path + i);
			}
			/* root level has p_bh == NULL, brelse() eats this */
			brelse(path[i].p_bh);
			path[i].p_bh = NULL;
			i--;
			ext_debug("return to level %d\n", i);
		}
	}

	/* TODO: flexible tree reduction should be here */
	if (path->p_hdr->eh_entries == 0) {
		/*
		 * truncate to zero freed all the tree,
		 * so we need to correct eh_depth
		 */
		err = ext4_ext_get_access(handle, inode, path);
		if (err == 0) {
			ext_inode_hdr(inode)->eh_depth = 0;
			ext_inode_hdr(inode)->eh_max =
				cpu_to_le16(ext4_ext_space_root(inode, 0));
			err = ext4_ext_dirty(handle, inode, path);
		}
	}
out:
	ext4_ext_drop_refs(path);
	kfree(path);
	if (err == -EAGAIN)
		goto again;
	ext4_journal_stop(handle);

	return err;
}

/*
 * called at mount time
 */
void ext4_ext_init(struct super_block *sb)
{
	/*
	 * possible initialization would be here
	 */

	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
		printk(KERN_INFO "EXT4-fs: file extents enabled");
#ifdef AGGRESSIVE_TEST
		printk(", aggressive tests");
#endif
#ifdef CHECK_BINSEARCH
		printk(", check binsearch");
#endif
#ifdef EXTENTS_STATS
		printk(", stats");
#endif
		printk("\n");
#endif
#ifdef EXTENTS_STATS
		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
		EXT4_SB(sb)->s_ext_min = 1 << 30;
		EXT4_SB(sb)->s_ext_max = 0;
#endif
	}
}

/*
 * called at umount time
 */
void ext4_ext_release(struct super_block *sb)
{
	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
		return;

#ifdef EXTENTS_STATS
	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
		struct ext4_sb_info *sbi = EXT4_SB(sb);
		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
			sbi->s_ext_blocks, sbi->s_ext_extents,
			sbi->s_ext_blocks / sbi->s_ext_extents);
		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
	}
#endif
}

/* FIXME!! we need to try to merge to left or right after zero-out  */
static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
{
	ext4_fsblk_t ee_pblock;
	unsigned int ee_len;
	int ret;

	ee_len    = ext4_ext_get_actual_len(ex);
	ee_pblock = ext4_ext_pblock(ex);

	ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
	if (ret > 0)
		ret = 0;

	return ret;
}

#define EXT4_EXT_ZERO_LEN 7
/*
 * This function is called by ext4_ext_map_blocks() if someone tries to write
 * to an uninitialized extent. It may result in splitting the uninitialized
 * extent into multiple extents (upto three - one initialized and two
 * uninitialized).
 * There are three possibilities:
 *   a> There is no split required: Entire extent should be initialized
 *   b> Splits in two extents: Write is happening at either end of the extent
 *   c> Splits in three extents: Somone is writing in middle of the extent
 */
static int ext4_ext_convert_to_initialized(handle_t *handle,
					   struct inode *inode,
					   struct ext4_map_blocks *map,
					   struct ext4_ext_path *path)
{
	struct ext4_extent *ex, newex, orig_ex;
	struct ext4_extent *ex1 = NULL;
	struct ext4_extent *ex2 = NULL;
	struct ext4_extent *ex3 = NULL;
	struct ext4_extent_header *eh;
	ext4_lblk_t ee_block, eof_block;
	unsigned int allocated, ee_len, depth;
	ext4_fsblk_t newblock;
	int err = 0;
	int ret = 0;
	int may_zeroout;

	ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
		"block %llu, max_blocks %u\n", inode->i_ino,
		(unsigned long long)map->m_lblk, map->m_len);

	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
		inode->i_sb->s_blocksize_bits;
	if (eof_block < map->m_lblk + map->m_len)
		eof_block = map->m_lblk + map->m_len;

	depth = ext_depth(inode);
	eh = path[depth].p_hdr;
	ex = path[depth].p_ext;
	ee_block = le32_to_cpu(ex->ee_block);
	ee_len = ext4_ext_get_actual_len(ex);
	allocated = ee_len - (map->m_lblk - ee_block);
	newblock = map->m_lblk - ee_block + ext4_ext_pblock(ex);

	ex2 = ex;
	orig_ex.ee_block = ex->ee_block;
	orig_ex.ee_len   = cpu_to_le16(ee_len);
	ext4_ext_store_pblock(&orig_ex, ext4_ext_pblock(ex));

	/*
	 * It is safe to convert extent to initialized via explicit
	 * zeroout only if extent is fully insde i_size or new_size.
	 */
	may_zeroout = ee_block + ee_len <= eof_block;

	err = ext4_ext_get_access(handle, inode, path + depth);
	if (err)
		goto out;
	/* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
	if (ee_len <= 2*EXT4_EXT_ZERO_LEN && may_zeroout) {
		err =  ext4_ext_zeroout(inode, &orig_ex);
		if (err)
			goto fix_extent_len;
		/* update the extent length and mark as initialized */
		ex->ee_block = orig_ex.ee_block;
		ex->ee_len   = orig_ex.ee_len;
		ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
		ext4_ext_dirty(handle, inode, path + depth);
		/* zeroed the full extent */
		return allocated;
	}

	/* ex1: ee_block to map->m_lblk - 1 : uninitialized */
	if (map->m_lblk > ee_block) {
		ex1 = ex;
		ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
		ext4_ext_mark_uninitialized(ex1);
		ex2 = &newex;
	}
	/*
	 * for sanity, update the length of the ex2 extent before
	 * we insert ex3, if ex1 is NULL. This is to avoid temporary
	 * overlap of blocks.
	 */
	if (!ex1 && allocated > map->m_len)
		ex2->ee_len = cpu_to_le16(map->m_len);
	/* ex3: to ee_block + ee_len : uninitialised */
	if (allocated > map->m_len) {
		unsigned int newdepth;
		/* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
		if (allocated <= EXT4_EXT_ZERO_LEN && may_zeroout) {
			/*
			 * map->m_lblk == ee_block is handled by the zerouout
			 * at the beginning.
			 * Mark first half uninitialized.
			 * Mark second half initialized and zero out the
			 * initialized extent
			 */
			ex->ee_block = orig_ex.ee_block;
			ex->ee_len   = cpu_to_le16(ee_len - allocated);
			ext4_ext_mark_uninitialized(ex);
			ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
			ext4_ext_dirty(handle, inode, path + depth);

			ex3 = &newex;
			ex3->ee_block = cpu_to_le32(map->m_lblk);
			ext4_ext_store_pblock(ex3, newblock);
			ex3->ee_len = cpu_to_le16(allocated);
			err = ext4_ext_insert_extent(handle, inode, path,
							ex3, 0);
			if (err == -ENOSPC) {
				err =  ext4_ext_zeroout(inode, &orig_ex);
				if (err)
					goto fix_extent_len;
				ex->ee_block = orig_ex.ee_block;
				ex->ee_len   = orig_ex.ee_len;
				ext4_ext_store_pblock(ex,
					ext4_ext_pblock(&orig_ex));
				ext4_ext_dirty(handle, inode, path + depth);
				/* blocks available from map->m_lblk */
				return allocated;

			} else if (err)
				goto fix_extent_len;

			/*
			 * We need to zero out the second half because
			 * an fallocate request can update file size and
			 * converting the second half to initialized extent
			 * implies that we can leak some junk data to user
			 * space.
			 */
			err =  ext4_ext_zeroout(inode, ex3);
			if (err) {
				/*
				 * We should actually mark the
				 * second half as uninit and return error
				 * Insert would have changed the extent
				 */
				depth = ext_depth(inode);
				ext4_ext_drop_refs(path);
				path = ext4_ext_find_extent(inode, map->m_lblk,
							    path);
				if (IS_ERR(path)) {
					err = PTR_ERR(path);
					return err;
				}
				/* get the second half extent details */
				ex = path[depth].p_ext;
				err = ext4_ext_get_access(handle, inode,
								path + depth);
				if (err)
					return err;
				ext4_ext_mark_uninitialized(ex);
				ext4_ext_dirty(handle, inode, path + depth);
				return err;
			}

			/* zeroed the second half */
			return allocated;
		}
		ex3 = &newex;
		ex3->ee_block = cpu_to_le32(map->m_lblk + map->m_len);
		ext4_ext_store_pblock(ex3, newblock + map->m_len);
		ex3->ee_len = cpu_to_le16(allocated - map->m_len);
		ext4_ext_mark_uninitialized(ex3);
		err = ext4_ext_insert_extent(handle, inode, path, ex3, 0);
		if (err == -ENOSPC && may_zeroout) {
			err =  ext4_ext_zeroout(inode, &orig_ex);
			if (err)
				goto fix_extent_len;
			/* update the extent length and mark as initialized */
			ex->ee_block = orig_ex.ee_block;
			ex->ee_len   = orig_ex.ee_len;
			ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
			ext4_ext_dirty(handle, inode, path + depth);
			/* zeroed the full extent */
			/* blocks available from map->m_lblk */
			return allocated;

		} else if (err)
			goto fix_extent_len;
		/*
		 * The depth, and hence eh & ex might change
		 * as part of the insert above.
		 */
		newdepth = ext_depth(inode);
		/*
		 * update the extent length after successful insert of the
		 * split extent
		 */
		ee_len -= ext4_ext_get_actual_len(ex3);
		orig_ex.ee_len = cpu_to_le16(ee_len);
		may_zeroout = ee_block + ee_len <= eof_block;

		depth = newdepth;
		ext4_ext_drop_refs(path);
		path = ext4_ext_find_extent(inode, map->m_lblk, path);
		if (IS_ERR(path)) {
			err = PTR_ERR(path);
			goto out;
		}
		eh = path[depth].p_hdr;
		ex = path[depth].p_ext;
		if (ex2 != &newex)
			ex2 = ex;

		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			goto out;

		allocated = map->m_len;

		/* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
		 * to insert a extent in the middle zerout directly
		 * otherwise give the extent a chance to merge to left
		 */
		if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
			map->m_lblk != ee_block && may_zeroout) {
			err =  ext4_ext_zeroout(inode, &orig_ex);
			if (err)
				goto fix_extent_len;
			/* update the extent length and mark as initialized */
			ex->ee_block = orig_ex.ee_block;
			ex->ee_len   = orig_ex.ee_len;
			ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
			ext4_ext_dirty(handle, inode, path + depth);
			/* zero out the first half */
			/* blocks available from map->m_lblk */
			return allocated;
		}
	}
	/*
	 * If there was a change of depth as part of the
	 * insertion of ex3 above, we need to update the length
	 * of the ex1 extent again here
	 */
	if (ex1 && ex1 != ex) {
		ex1 = ex;
		ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
		ext4_ext_mark_uninitialized(ex1);
		ex2 = &newex;
	}
	/* ex2: map->m_lblk to map->m_lblk + maxblocks-1 : initialised */
	ex2->ee_block = cpu_to_le32(map->m_lblk);
	ext4_ext_store_pblock(ex2, newblock);
	ex2->ee_len = cpu_to_le16(allocated);
	if (ex2 != ex)
		goto insert;
	/*
	 * New (initialized) extent starts from the first block
	 * in the current extent. i.e., ex2 == ex
	 * We have to see if it can be merged with the extent
	 * on the left.
	 */
	if (ex2 > EXT_FIRST_EXTENT(eh)) {
		/*
		 * To merge left, pass "ex2 - 1" to try_to_merge(),
		 * since it merges towards right _only_.
		 */
		ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
		if (ret) {
			err = ext4_ext_correct_indexes(handle, inode, path);
			if (err)
				goto out;
			depth = ext_depth(inode);
			ex2--;
		}
	}
	/*
	 * Try to Merge towards right. This might be required
	 * only when the whole extent is being written to.
	 * i.e. ex2 == ex and ex3 == NULL.
	 */
	if (!ex3) {
		ret = ext4_ext_try_to_merge(inode, path, ex2);
		if (ret) {
			err = ext4_ext_correct_indexes(handle, inode, path);
			if (err)
				goto out;
		}
	}
	/* Mark modified extent as dirty */
	err = ext4_ext_dirty(handle, inode, path + depth);
	goto out;
insert:
	err = ext4_ext_insert_extent(handle, inode, path, &newex, 0);
	if (err == -ENOSPC && may_zeroout) {
		err =  ext4_ext_zeroout(inode, &orig_ex);
		if (err)
			goto fix_extent_len;
		/* update the extent length and mark as initialized */
		ex->ee_block = orig_ex.ee_block;
		ex->ee_len   = orig_ex.ee_len;
		ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
		ext4_ext_dirty(handle, inode, path + depth);
		/* zero out the first half */
		return allocated;
	} else if (err)
		goto fix_extent_len;
out:
	ext4_ext_show_leaf(inode, path);
	return err ? err : allocated;

fix_extent_len:
	ex->ee_block = orig_ex.ee_block;
	ex->ee_len   = orig_ex.ee_len;
	ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
	ext4_ext_mark_uninitialized(ex);
	ext4_ext_dirty(handle, inode, path + depth);
	return err;
}

/*
 * This function is called by ext4_ext_map_blocks() from
 * ext4_get_blocks_dio_write() when DIO to write
 * to an uninitialized extent.
 *
 * Writing to an uninitized extent may result in splitting the uninitialized
 * extent into multiple /intialized unintialized extents (up to three)
 * There are three possibilities:
 *   a> There is no split required: Entire extent should be uninitialized
 *   b> Splits in two extents: Write is happening at either end of the extent
 *   c> Splits in three extents: Somone is writing in middle of the extent
 *
 * One of more index blocks maybe needed if the extent tree grow after
 * the unintialized extent split. To prevent ENOSPC occur at the IO
 * complete, we need to split the uninitialized extent before DIO submit
 * the IO. The uninitialized extent called at this time will be split
 * into three uninitialized extent(at most). After IO complete, the part
 * being filled will be convert to initialized by the end_io callback function
 * via ext4_convert_unwritten_extents().
 *
 * Returns the size of uninitialized extent to be written on success.
 */
static int ext4_split_unwritten_extents(handle_t *handle,
					struct inode *inode,
					struct ext4_map_blocks *map,
					struct ext4_ext_path *path,
					int flags)
{
	struct ext4_extent *ex, newex, orig_ex;
	struct ext4_extent *ex1 = NULL;
	struct ext4_extent *ex2 = NULL;
	struct ext4_extent *ex3 = NULL;
	ext4_lblk_t ee_block, eof_block;
	unsigned int allocated, ee_len, depth;
	ext4_fsblk_t newblock;
	int err = 0;
	int may_zeroout;

	ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
		"block %llu, max_blocks %u\n", inode->i_ino,
		(unsigned long long)map->m_lblk, map->m_len);

	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
		inode->i_sb->s_blocksize_bits;
	if (eof_block < map->m_lblk + map->m_len)
		eof_block = map->m_lblk + map->m_len;

	depth = ext_depth(inode);
	ex = path[depth].p_ext;
	ee_block = le32_to_cpu(ex->ee_block);
	ee_len = ext4_ext_get_actual_len(ex);
	allocated = ee_len - (map->m_lblk - ee_block);
	newblock = map->m_lblk - ee_block + ext4_ext_pblock(ex);

	ex2 = ex;
	orig_ex.ee_block = ex->ee_block;
	orig_ex.ee_len   = cpu_to_le16(ee_len);
	ext4_ext_store_pblock(&orig_ex, ext4_ext_pblock(ex));

	/*
	 * It is safe to convert extent to initialized via explicit
	 * zeroout only if extent is fully insde i_size or new_size.
	 */
	may_zeroout = ee_block + ee_len <= eof_block;

	/*
 	 * If the uninitialized extent begins at the same logical
 	 * block where the write begins, and the write completely
 	 * covers the extent, then we don't need to split it.
 	 */
	if ((map->m_lblk == ee_block) && (allocated <= map->m_len))
		return allocated;

	err = ext4_ext_get_access(handle, inode, path + depth);
	if (err)
		goto out;
	/* ex1: ee_block to map->m_lblk - 1 : uninitialized */
	if (map->m_lblk > ee_block) {
		ex1 = ex;
		ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
		ext4_ext_mark_uninitialized(ex1);
		ex2 = &newex;
	}
	/*
	 * for sanity, update the length of the ex2 extent before
	 * we insert ex3, if ex1 is NULL. This is to avoid temporary
	 * overlap of blocks.
	 */
	if (!ex1 && allocated > map->m_len)
		ex2->ee_len = cpu_to_le16(map->m_len);
	/* ex3: to ee_block + ee_len : uninitialised */
	if (allocated > map->m_len) {
		unsigned int newdepth;
		ex3 = &newex;
		ex3->ee_block = cpu_to_le32(map->m_lblk + map->m_len);
		ext4_ext_store_pblock(ex3, newblock + map->m_len);
		ex3->ee_len = cpu_to_le16(allocated - map->m_len);
		ext4_ext_mark_uninitialized(ex3);
		err = ext4_ext_insert_extent(handle, inode, path, ex3, flags);
		if (err == -ENOSPC && may_zeroout) {
			err =  ext4_ext_zeroout(inode, &orig_ex);
			if (err)
				goto fix_extent_len;
			/* update the extent length and mark as initialized */
			ex->ee_block = orig_ex.ee_block;
			ex->ee_len   = orig_ex.ee_len;
			ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
			ext4_ext_dirty(handle, inode, path + depth);
			/* zeroed the full extent */
			/* blocks available from map->m_lblk */
			return allocated;

		} else if (err)
			goto fix_extent_len;
		/*
		 * The depth, and hence eh & ex might change
		 * as part of the insert above.
		 */
		newdepth = ext_depth(inode);
		/*
		 * update the extent length after successful insert of the
		 * split extent
		 */
		ee_len -= ext4_ext_get_actual_len(ex3);
		orig_ex.ee_len = cpu_to_le16(ee_len);
		may_zeroout = ee_block + ee_len <= eof_block;

		depth = newdepth;
		ext4_ext_drop_refs(path);
		path = ext4_ext_find_extent(inode, map->m_lblk, path);
		if (IS_ERR(path)) {
			err = PTR_ERR(path);
			goto out;
		}
		ex = path[depth].p_ext;
		if (ex2 != &newex)
			ex2 = ex;

		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			goto out;

		allocated = map->m_len;
	}
	/*
	 * If there was a change of depth as part of the
	 * insertion of ex3 above, we need to update the length
	 * of the ex1 extent again here
	 */
	if (ex1 && ex1 != ex) {
		ex1 = ex;
		ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
		ext4_ext_mark_uninitialized(ex1);
		ex2 = &newex;
	}
	/*
	 * ex2: map->m_lblk to map->m_lblk + map->m_len-1 : to be written
	 * using direct I/O, uninitialised still.
	 */
	ex2->ee_block = cpu_to_le32(map->m_lblk);
	ext4_ext_store_pblock(ex2, newblock);
	ex2->ee_len = cpu_to_le16(allocated);
	ext4_ext_mark_uninitialized(ex2);
	if (ex2 != ex)
		goto insert;
	/* Mark modified extent as dirty */
	err = ext4_ext_dirty(handle, inode, path + depth);
	ext_debug("out here\n");
	goto out;
insert:
	err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
	if (err == -ENOSPC && may_zeroout) {
		err =  ext4_ext_zeroout(inode, &orig_ex);
		if (err)
			goto fix_extent_len;
		/* update the extent length and mark as initialized */
		ex->ee_block = orig_ex.ee_block;
		ex->ee_len   = orig_ex.ee_len;
		ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
		ext4_ext_dirty(handle, inode, path + depth);
		/* zero out the first half */
		return allocated;
	} else if (err)
		goto fix_extent_len;
out:
	ext4_ext_show_leaf(inode, path);
	return err ? err : allocated;

fix_extent_len:
	ex->ee_block = orig_ex.ee_block;
	ex->ee_len   = orig_ex.ee_len;
	ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
	ext4_ext_mark_uninitialized(ex);
	ext4_ext_dirty(handle, inode, path + depth);
	return err;
}
static int ext4_convert_unwritten_extents_endio(handle_t *handle,
					      struct inode *inode,
					      struct ext4_ext_path *path)
{
	struct ext4_extent *ex;
	struct ext4_extent_header *eh;
	int depth;
	int err = 0;
	int ret = 0;

	depth = ext_depth(inode);
	eh = path[depth].p_hdr;
	ex = path[depth].p_ext;

	err = ext4_ext_get_access(handle, inode, path + depth);
	if (err)
		goto out;
	/* first mark the extent as initialized */
	ext4_ext_mark_initialized(ex);

	/*
	 * We have to see if it can be merged with the extent
	 * on the left.
	 */
	if (ex > EXT_FIRST_EXTENT(eh)) {
		/*
		 * To merge left, pass "ex - 1" to try_to_merge(),
		 * since it merges towards right _only_.
		 */
		ret = ext4_ext_try_to_merge(inode, path, ex - 1);
		if (ret) {
			err = ext4_ext_correct_indexes(handle, inode, path);
			if (err)
				goto out;
			depth = ext_depth(inode);
			ex--;
		}
	}
	/*
	 * Try to Merge towards right.
	 */
	ret = ext4_ext_try_to_merge(inode, path, ex);
	if (ret) {
		err = ext4_ext_correct_indexes(handle, inode, path);
		if (err)
			goto out;
		depth = ext_depth(inode);
	}
	/* Mark modified extent as dirty */
	err = ext4_ext_dirty(handle, inode, path + depth);
out:
	ext4_ext_show_leaf(inode, path);
	return err;
}

static void unmap_underlying_metadata_blocks(struct block_device *bdev,
			sector_t block, int count)
{
	int i;
	for (i = 0; i < count; i++)
                unmap_underlying_metadata(bdev, block + i);
}

/*
 * Handle EOFBLOCKS_FL flag, clearing it if necessary
 */
static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
			      ext4_lblk_t lblk,
			      struct ext4_ext_path *path,
			      unsigned int len)
{
	int i, depth;
	struct ext4_extent_header *eh;
	struct ext4_extent *ex, *last_ex;

	if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
		return 0;

	depth = ext_depth(inode);
	eh = path[depth].p_hdr;
	ex = path[depth].p_ext;

	if (unlikely(!eh->eh_entries)) {
		EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
				 "EOFBLOCKS_FL set");
		return -EIO;
	}
	last_ex = EXT_LAST_EXTENT(eh);
	/*
	 * We should clear the EOFBLOCKS_FL flag if we are writing the
	 * last block in the last extent in the file.  We test this by
	 * first checking to see if the caller to
	 * ext4_ext_get_blocks() was interested in the last block (or
	 * a block beyond the last block) in the current extent.  If
	 * this turns out to be false, we can bail out from this
	 * function immediately.
	 */
	if (lblk + len < le32_to_cpu(last_ex->ee_block) +
	    ext4_ext_get_actual_len(last_ex))
		return 0;
	/*
	 * If the caller does appear to be planning to write at or
	 * beyond the end of the current extent, we then test to see
	 * if the current extent is the last extent in the file, by
	 * checking to make sure it was reached via the rightmost node
	 * at each level of the tree.
	 */
	for (i = depth-1; i >= 0; i--)
		if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
			return 0;
	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
	return ext4_mark_inode_dirty(handle, inode);
}

static int
ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
			struct ext4_map_blocks *map,
			struct ext4_ext_path *path, int flags,
			unsigned int allocated, ext4_fsblk_t newblock)
{
	int ret = 0;
	int err = 0;
	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;

	ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
		  "block %llu, max_blocks %u, flags %d, allocated %u",
		  inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
		  flags, allocated);
	ext4_ext_show_leaf(inode, path);

	/* get_block() before submit the IO, split the extent */
	if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
		ret = ext4_split_unwritten_extents(handle, inode, map,
						   path, flags);
		/*
		 * Flag the inode(non aio case) or end_io struct (aio case)
		 * that this IO needs to convertion to written when IO is
		 * completed
		 */
		if (io)
			io->flag = EXT4_IO_END_UNWRITTEN;
		else
			ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
		if (ext4_should_dioread_nolock(inode))
			map->m_flags |= EXT4_MAP_UNINIT;
		goto out;
	}
	/* IO end_io complete, convert the filled extent to written */
	if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
		ret = ext4_convert_unwritten_extents_endio(handle, inode,
							path);
		if (ret >= 0) {
			ext4_update_inode_fsync_trans(handle, inode, 1);
			err = check_eofblocks_fl(handle, inode, map->m_lblk,
						 path, map->m_len);
		} else
			err = ret;
		goto out2;
	}
	/* buffered IO case */
	/*
	 * repeat fallocate creation request
	 * we already have an unwritten extent
	 */
	if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
		goto map_out;

	/* buffered READ or buffered write_begin() lookup */
	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
		/*
		 * We have blocks reserved already.  We
		 * return allocated blocks so that delalloc
		 * won't do block reservation for us.  But
		 * the buffer head will be unmapped so that
		 * a read from the block returns 0s.
		 */
		map->m_flags |= EXT4_MAP_UNWRITTEN;
		goto out1;
	}

	/* buffered write, writepage time, convert*/
	ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
	if (ret >= 0) {
		ext4_update_inode_fsync_trans(handle, inode, 1);
		err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
					 map->m_len);
		if (err < 0)
			goto out2;
	}

out:
	if (ret <= 0) {
		err = ret;
		goto out2;
	} else
		allocated = ret;
	map->m_flags |= EXT4_MAP_NEW;
	/*
	 * if we allocated more blocks than requested
	 * we need to make sure we unmap the extra block
	 * allocated. The actual needed block will get
	 * unmapped later when we find the buffer_head marked
	 * new.
	 */
	if (allocated > map->m_len) {
		unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
					newblock + map->m_len,
					allocated - map->m_len);
		allocated = map->m_len;
	}

	/*
	 * If we have done fallocate with the offset that is already
	 * delayed allocated, we would have block reservation
	 * and quota reservation done in the delayed write path.
	 * But fallocate would have already updated quota and block
	 * count for this offset. So cancel these reservation
	 */
	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
		ext4_da_update_reserve_space(inode, allocated, 0);

map_out:
	map->m_flags |= EXT4_MAP_MAPPED;
out1:
	if (allocated > map->m_len)
		allocated = map->m_len;
	ext4_ext_show_leaf(inode, path);
	map->m_pblk = newblock;
	map->m_len = allocated;
out2:
	if (path) {
		ext4_ext_drop_refs(path);
		kfree(path);
	}
	return err ? err : allocated;
}

/*
 * Block allocation/map/preallocation routine for extents based files
 *
 *
 * Need to be called with
 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
 *
 * return > 0, number of of blocks already mapped/allocated
 *          if create == 0 and these are pre-allocated blocks
 *          	buffer head is unmapped
 *          otherwise blocks are mapped
 *
 * return = 0, if plain look up failed (blocks have not been allocated)
 *          buffer head is unmapped
 *
 * return < 0, error case.
 */
int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
			struct ext4_map_blocks *map, int flags)
{
	struct ext4_ext_path *path = NULL;
	struct ext4_extent_header *eh;
	struct ext4_extent newex, *ex;
	ext4_fsblk_t newblock;
	int err = 0, depth, ret;
	unsigned int allocated = 0;
	struct ext4_allocation_request ar;
	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;

	ext_debug("blocks %u/%u requested for inode %lu\n",
		  map->m_lblk, map->m_len, inode->i_ino);

	/* check in cache */
	if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
		if (!newex.ee_start_lo && !newex.ee_start_hi) {
			if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
				/*
				 * block isn't allocated yet and
				 * user doesn't want to allocate it
				 */
				goto out2;
			}
			/* we should allocate requested block */
		} else {
			/* block is already allocated */
			newblock = map->m_lblk
				   - le32_to_cpu(newex.ee_block)
				   + ext4_ext_pblock(&newex);
			/* number of remaining blocks in the extent */
			allocated = ext4_ext_get_actual_len(&newex) -
				(map->m_lblk - le32_to_cpu(newex.ee_block));
			goto out;
		}
	}

	/* find extent for this block */
	path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
	if (IS_ERR(path)) {
		err = PTR_ERR(path);
		path = NULL;
		goto out2;
	}

	depth = ext_depth(inode);

	/*
	 * consistent leaf must not be empty;
	 * this situation is possible, though, _during_ tree modification;
	 * this is why assert can't be put in ext4_ext_find_extent()
	 */
	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
		EXT4_ERROR_INODE(inode, "bad extent address "
				 "lblock: %lu, depth: %d pblock %lld",
				 (unsigned long) map->m_lblk, depth,
				 path[depth].p_block);
		err = -EIO;
		goto out2;
	}
	eh = path[depth].p_hdr;

	ex = path[depth].p_ext;
	if (ex) {
		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
		unsigned short ee_len;

		/*
		 * Uninitialized extents are treated as holes, except that
		 * we split out initialized portions during a write.
		 */
		ee_len = ext4_ext_get_actual_len(ex);
		/* if found extent covers block, simply return it */
		if (in_range(map->m_lblk, ee_block, ee_len)) {
			newblock = map->m_lblk - ee_block + ee_start;
			/* number of remaining blocks in the extent */
			allocated = ee_len - (map->m_lblk - ee_block);
			ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
				  ee_block, ee_len, newblock);

			/* Do not put uninitialized extent in the cache */
			if (!ext4_ext_is_uninitialized(ex)) {
				ext4_ext_put_in_cache(inode, ee_block,
							ee_len, ee_start);
				goto out;
			}
			ret = ext4_ext_handle_uninitialized_extents(handle,
					inode, map, path, flags, allocated,
					newblock);
			return ret;
		}
	}

	/*
	 * requested block isn't allocated yet;
	 * we couldn't try to create block if create flag is zero
	 */
	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
		/*
		 * put just found gap into cache to speed up
		 * subsequent requests
		 */
		ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
		goto out2;
	}
	/*
	 * Okay, we need to do block allocation.
	 */

	/* find neighbour allocated blocks */
	ar.lleft = map->m_lblk;
	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
	if (err)
		goto out2;
	ar.lright = map->m_lblk;
	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
	if (err)
		goto out2;

	/*
	 * See if request is beyond maximum number of blocks we can have in
	 * a single extent. For an initialized extent this limit is
	 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
	 * EXT_UNINIT_MAX_LEN.
	 */
	if (map->m_len > EXT_INIT_MAX_LEN &&
	    !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
		map->m_len = EXT_INIT_MAX_LEN;
	else if (map->m_len > EXT_UNINIT_MAX_LEN &&
		 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
		map->m_len = EXT_UNINIT_MAX_LEN;

	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
	newex.ee_block = cpu_to_le32(map->m_lblk);
	newex.ee_len = cpu_to_le16(map->m_len);
	err = ext4_ext_check_overlap(inode, &newex, path);
	if (err)
		allocated = ext4_ext_get_actual_len(&newex);
	else
		allocated = map->m_len;

	/* allocate new block */
	ar.inode = inode;
	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
	ar.logical = map->m_lblk;
	ar.len = allocated;
	if (S_ISREG(inode->i_mode))
		ar.flags = EXT4_MB_HINT_DATA;
	else
		/* disable in-core preallocation for non-regular files */
		ar.flags = 0;
	newblock = ext4_mb_new_blocks(handle, &ar, &err);
	if (!newblock)
		goto out2;
	ext_debug("allocate new block: goal %llu, found %llu/%u\n",
		  ar.goal, newblock, allocated);

	/* try to insert new extent into found leaf and return */
	ext4_ext_store_pblock(&newex, newblock);
	newex.ee_len = cpu_to_le16(ar.len);
	/* Mark uninitialized */
	if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
		ext4_ext_mark_uninitialized(&newex);
		/*
		 * io_end structure was created for every IO write to an
		 * uninitialized extent. To avoid unecessary conversion,
		 * here we flag the IO that really needs the conversion.
		 * For non asycn direct IO case, flag the inode state
		 * that we need to perform convertion when IO is done.
		 */
		if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
			if (io)
				io->flag = EXT4_IO_END_UNWRITTEN;
			else
				ext4_set_inode_state(inode,
						     EXT4_STATE_DIO_UNWRITTEN);
		}
		if (ext4_should_dioread_nolock(inode))
			map->m_flags |= EXT4_MAP_UNINIT;
	}

	err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
	if (err)
		goto out2;

	err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
	if (err) {
		/* free data blocks we just allocated */
		/* not a good idea to call discard here directly,
		 * but otherwise we'd need to call it every free() */
		ext4_discard_preallocations(inode);
		ext4_free_blocks(handle, inode, 0, ext4_ext_pblock(&newex),
				 ext4_ext_get_actual_len(&newex), 0);
		goto out2;
	}

	/* previous routine could use block we allocated */
	newblock = ext4_ext_pblock(&newex);
	allocated = ext4_ext_get_actual_len(&newex);
	if (allocated > map->m_len)
		allocated = map->m_len;
	map->m_flags |= EXT4_MAP_NEW;

	/*
	 * Update reserved blocks/metadata blocks after successful
	 * block allocation which had been deferred till now.
	 */
	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
		ext4_da_update_reserve_space(inode, allocated, 1);

	/*
	 * Cache the extent and update transaction to commit on fdatasync only
	 * when it is _not_ an uninitialized extent.
	 */
	if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
		ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
		ext4_update_inode_fsync_trans(handle, inode, 1);
	} else
		ext4_update_inode_fsync_trans(handle, inode, 0);
out:
	if (allocated > map->m_len)
		allocated = map->m_len;
	ext4_ext_show_leaf(inode, path);
	map->m_flags |= EXT4_MAP_MAPPED;
	map->m_pblk = newblock;
	map->m_len = allocated;
out2:
	if (path) {
		ext4_ext_drop_refs(path);
		kfree(path);
	}
	return err ? err : allocated;
}

void ext4_ext_truncate(struct inode *inode)
{
	struct address_space *mapping = inode->i_mapping;
	struct super_block *sb = inode->i_sb;
	ext4_lblk_t last_block;
	handle_t *handle;
	int err = 0;

	/*
	 * finish any pending end_io work so we won't run the risk of
	 * converting any truncated blocks to initialized later
	 */
	ext4_flush_completed_IO(inode);

	/*
	 * probably first extent we're gonna free will be last in block
	 */
	err = ext4_writepage_trans_blocks(inode);
	handle = ext4_journal_start(inode, err);
	if (IS_ERR(handle))
		return;

	if (inode->i_size & (sb->s_blocksize - 1))
		ext4_block_truncate_page(handle, mapping, inode->i_size);

	if (ext4_orphan_add(handle, inode))
		goto out_stop;

	down_write(&EXT4_I(inode)->i_data_sem);
	ext4_ext_invalidate_cache(inode);

	ext4_discard_preallocations(inode);

	/*
	 * TODO: optimization is possible here.
	 * Probably we need not scan at all,
	 * because page truncation is enough.
	 */

	/* we have to know where to truncate from in crash case */
	EXT4_I(inode)->i_disksize = inode->i_size;
	ext4_mark_inode_dirty(handle, inode);

	last_block = (inode->i_size + sb->s_blocksize - 1)
			>> EXT4_BLOCK_SIZE_BITS(sb);
	err = ext4_ext_remove_space(inode, last_block);

	/* In a multi-transaction truncate, we only make the final
	 * transaction synchronous.
	 */
	if (IS_SYNC(inode))
		ext4_handle_sync(handle);

out_stop:
	up_write(&EXT4_I(inode)->i_data_sem);
	/*
	 * If this was a simple ftruncate() and the file will remain alive,
	 * then we need to clear up the orphan record which we created above.
	 * However, if this was a real unlink then we were called by
	 * ext4_delete_inode(), and we allow that function to clean up the
	 * orphan info for us.
	 */
	if (inode->i_nlink)
		ext4_orphan_del(handle, inode);

	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
	ext4_mark_inode_dirty(handle, inode);
	ext4_journal_stop(handle);
}

static void ext4_falloc_update_inode(struct inode *inode,
				int mode, loff_t new_size, int update_ctime)
{
	struct timespec now;

	if (update_ctime) {
		now = current_fs_time(inode->i_sb);
		if (!timespec_equal(&inode->i_ctime, &now))
			inode->i_ctime = now;
	}
	/*
	 * Update only when preallocation was requested beyond
	 * the file size.
	 */
	if (!(mode & FALLOC_FL_KEEP_SIZE)) {
		if (new_size > i_size_read(inode))
			i_size_write(inode, new_size);
		if (new_size > EXT4_I(inode)->i_disksize)
			ext4_update_i_disksize(inode, new_size);
	} else {
		/*
		 * Mark that we allocate beyond EOF so the subsequent truncate
		 * can proceed even if the new size is the same as i_size.
		 */
		if (new_size > i_size_read(inode))
			ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
	}

}

/*
 * preallocate space for a file. This implements ext4's fallocate inode
 * operation, which gets called from sys_fallocate system call.
 * For block-mapped files, posix_fallocate should fall back to the method
 * of writing zeroes to the required new blocks (the same behavior which is
 * expected for file systems which do not support fallocate() system call).
 */
long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
{
	handle_t *handle;
	loff_t new_size;
	unsigned int max_blocks;
	int ret = 0;
	int ret2 = 0;
	int retries = 0;
	struct ext4_map_blocks map;
	unsigned int credits, blkbits = inode->i_blkbits;

	/*
	 * currently supporting (pre)allocate mode for extent-based
	 * files _only_
	 */
	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
		return -EOPNOTSUPP;

	/* preallocation to directories is currently not supported */
	if (S_ISDIR(inode->i_mode))
		return -ENODEV;

	map.m_lblk = offset >> blkbits;
	/*
	 * We can't just convert len to max_blocks because
	 * If blocksize = 4096 offset = 3072 and len = 2048
	 */
	max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
		- map.m_lblk;
	/*
	 * credits to insert 1 extent into extent tree
	 */
	credits = ext4_chunk_trans_blocks(inode, max_blocks);
	mutex_lock(&inode->i_mutex);
	ret = inode_newsize_ok(inode, (len + offset));
	if (ret) {
		mutex_unlock(&inode->i_mutex);
		return ret;
	}
retry:
	while (ret >= 0 && ret < max_blocks) {
		map.m_lblk = map.m_lblk + ret;
		map.m_len = max_blocks = max_blocks - ret;
		handle = ext4_journal_start(inode, credits);
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			break;
		}
		ret = ext4_map_blocks(handle, inode, &map,
				      EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
		if (ret <= 0) {
#ifdef EXT4FS_DEBUG
			WARN_ON(ret <= 0);
			printk(KERN_ERR "%s: ext4_ext_map_blocks "
				    "returned error inode#%lu, block=%u, "
				    "max_blocks=%u", __func__,
				    inode->i_ino, map.m_lblk, max_blocks);
#endif
			ext4_mark_inode_dirty(handle, inode);
			ret2 = ext4_journal_stop(handle);
			break;
		}
		if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
						blkbits) >> blkbits))
			new_size = offset + len;
		else
			new_size = (map.m_lblk + ret) << blkbits;

		ext4_falloc_update_inode(inode, mode, new_size,
					 (map.m_flags & EXT4_MAP_NEW));
		ext4_mark_inode_dirty(handle, inode);
		ret2 = ext4_journal_stop(handle);
		if (ret2)
			break;
	}
	if (ret == -ENOSPC &&
			ext4_should_retry_alloc(inode->i_sb, &retries)) {
		ret = 0;
		goto retry;
	}
	mutex_unlock(&inode->i_mutex);
	return ret > 0 ? ret2 : ret;
}

/*
 * This function convert a range of blocks to written extents
 * The caller of this function will pass the start offset and the size.
 * all unwritten extents within this range will be converted to
 * written extents.
 *
 * This function is called from the direct IO end io call back
 * function, to convert the fallocated extents after IO is completed.
 * Returns 0 on success.
 */
int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
				    ssize_t len)
{
	handle_t *handle;
	unsigned int max_blocks;
	int ret = 0;
	int ret2 = 0;
	struct ext4_map_blocks map;
	unsigned int credits, blkbits = inode->i_blkbits;

	map.m_lblk = offset >> blkbits;
	/*
	 * We can't just convert len to max_blocks because
	 * If blocksize = 4096 offset = 3072 and len = 2048
	 */
	max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
		      map.m_lblk);
	/*
	 * credits to insert 1 extent into extent tree
	 */
	credits = ext4_chunk_trans_blocks(inode, max_blocks);
	while (ret >= 0 && ret < max_blocks) {
		map.m_lblk += ret;
		map.m_len = (max_blocks -= ret);
		handle = ext4_journal_start(inode, credits);
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			break;
		}
		ret = ext4_map_blocks(handle, inode, &map,
				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
		if (ret <= 0) {
			WARN_ON(ret <= 0);
			printk(KERN_ERR "%s: ext4_ext_map_blocks "
				    "returned error inode#%lu, block=%u, "
				    "max_blocks=%u", __func__,
				    inode->i_ino, map.m_lblk, map.m_len);
		}
		ext4_mark_inode_dirty(handle, inode);
		ret2 = ext4_journal_stop(handle);
		if (ret <= 0 || ret2 )
			break;
	}
	return ret > 0 ? ret2 : ret;
}
/*
 * Callback function called for each extent to gather FIEMAP information.
 */
static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
		       struct ext4_ext_cache *newex, struct ext4_extent *ex,
		       void *data)
{
	struct fiemap_extent_info *fieinfo = data;
	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
	__u64	logical;
	__u64	physical;
	__u64	length;
	__u32	flags = 0;
	int	error;

	logical =  (__u64)newex->ec_block << blksize_bits;

	if (newex->ec_start == 0) {
		pgoff_t offset;
		struct page *page;
		struct buffer_head *bh = NULL;

		offset = logical >> PAGE_SHIFT;
		page = find_get_page(inode->i_mapping, offset);
		if (!page || !page_has_buffers(page))
			return EXT_CONTINUE;

		bh = page_buffers(page);

		if (!bh)
			return EXT_CONTINUE;

		if (buffer_delay(bh)) {
			flags |= FIEMAP_EXTENT_DELALLOC;
			page_cache_release(page);
		} else {
			page_cache_release(page);
			return EXT_CONTINUE;
		}
	}

	physical = (__u64)newex->ec_start << blksize_bits;
	length =   (__u64)newex->ec_len << blksize_bits;

	if (ex && ext4_ext_is_uninitialized(ex))
		flags |= FIEMAP_EXTENT_UNWRITTEN;

	/*
	 * If this extent reaches EXT_MAX_BLOCK, it must be last.
	 *
	 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK,
	 * this also indicates no more allocated blocks.
	 *
	 * XXX this might miss a single-block extent at EXT_MAX_BLOCK
	 */
	if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK ||
	    newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) {
		loff_t size = i_size_read(inode);
		loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb);

		flags |= FIEMAP_EXTENT_LAST;
		if ((flags & FIEMAP_EXTENT_DELALLOC) &&
		    logical+length > size)
			length = (size - logical + bs - 1) & ~(bs-1);
	}

	error = fiemap_fill_next_extent(fieinfo, logical, physical,
					length, flags);
	if (error < 0)
		return error;
	if (error == 1)
		return EXT_BREAK;

	return EXT_CONTINUE;
}

/* fiemap flags we can handle specified here */
#define EXT4_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)

static int ext4_xattr_fiemap(struct inode *inode,
				struct fiemap_extent_info *fieinfo)
{
	__u64 physical = 0;
	__u64 length;
	__u32 flags = FIEMAP_EXTENT_LAST;
	int blockbits = inode->i_sb->s_blocksize_bits;
	int error = 0;

	/* in-inode? */
	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
		struct ext4_iloc iloc;
		int offset;	/* offset of xattr in inode */

		error = ext4_get_inode_loc(inode, &iloc);
		if (error)
			return error;
		physical = iloc.bh->b_blocknr << blockbits;
		offset = EXT4_GOOD_OLD_INODE_SIZE +
				EXT4_I(inode)->i_extra_isize;
		physical += offset;
		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
		flags |= FIEMAP_EXTENT_DATA_INLINE;
		brelse(iloc.bh);
	} else { /* external block */
		physical = EXT4_I(inode)->i_file_acl << blockbits;
		length = inode->i_sb->s_blocksize;
	}

	if (physical)
		error = fiemap_fill_next_extent(fieinfo, 0, physical,
						length, flags);
	return (error < 0 ? error : 0);
}

int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		__u64 start, __u64 len)
{
	ext4_lblk_t start_blk;
	int error = 0;

	/* fallback to generic here if not in extents fmt */
	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
		return generic_block_fiemap(inode, fieinfo, start, len,
			ext4_get_block);

	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
		return -EBADR;

	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
		error = ext4_xattr_fiemap(inode, fieinfo);
	} else {
		ext4_lblk_t len_blks;
		__u64 last_blk;

		start_blk = start >> inode->i_sb->s_blocksize_bits;
		last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
		if (last_blk >= EXT_MAX_BLOCK)
			last_blk = EXT_MAX_BLOCK-1;
		len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;

		/*
		 * Walk the extent tree gathering extent information.
		 * ext4_ext_fiemap_cb will push extents back to user.
		 */
		error = ext4_ext_walk_space(inode, start_blk, len_blks,
					  ext4_ext_fiemap_cb, fieinfo);
	}

	return error;
}