summaryrefslogtreecommitdiffstats
path: root/xlators/cluster/dht/src/dht-rebalance.c
blob: fd07a1c7ec1f751a7533b2b96bc7bda4da777446 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
/*
  Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com>
  This file is part of GlusterFS.

  This file is licensed to you under your choice of the GNU Lesser
  General Public License, version 3 or any later version (LGPLv3 or
  later), or the GNU General Public License, version 2 (GPLv2), in all
  cases as published by the Free Software Foundation.
*/


#ifndef _CONFIG_H
#define _CONFIG_H
#include "config.h"
#endif

#include "dht-common.h"
#include "xlator.h"

#define GF_DISK_SECTOR_SIZE             512
#define DHT_REBALANCE_PID               4242 /* Change it if required */
#define DHT_REBALANCE_BLKSIZE           (128 * 1024)

static int
dht_write_with_holes (xlator_t *to, fd_t *fd, struct iovec *vec, int count,
                      int32_t size, off_t offset, struct iobref *iobref)
{
        int i            = 0;
        int ret          = -1;
        int start_idx    = 0;
        int tmp_offset   = 0;
        int write_needed = 0;
        int buf_len      = 0;
        int size_pending = 0;
        char *buf        = NULL;

        /* loop through each vector */
        for (i = 0; i < count; i++) {
                buf = vec[i].iov_base;
                buf_len = vec[i].iov_len;

                for (start_idx = 0; (start_idx + GF_DISK_SECTOR_SIZE) <= buf_len;
                     start_idx += GF_DISK_SECTOR_SIZE) {

                        if (mem_0filled (buf + start_idx, GF_DISK_SECTOR_SIZE) != 0) {
                                write_needed = 1;
                                continue;
                        }

                        if (write_needed) {
                                ret = syncop_write (to, fd, (buf + tmp_offset),
                                                    (start_idx - tmp_offset),
                                                    (offset + tmp_offset),
                                                    iobref, 0);
                                /* 'path' will be logged in calling function */
                                if (ret < 0) {
                                        gf_log (THIS->name, GF_LOG_WARNING,
                                                "failed to write (%s)",
                                                strerror (errno));
                                        goto out;
                                }

                                write_needed = 0;
                        }
                        tmp_offset = start_idx + GF_DISK_SECTOR_SIZE;
                }

                if ((start_idx < buf_len) || write_needed) {
                        /* This means, last chunk is not yet written.. write it */
                        ret = syncop_write (to, fd, (buf + tmp_offset),
                                            (buf_len - tmp_offset),
                                            (offset + tmp_offset), iobref, 0);
                        if (ret < 0) {
                                /* 'path' will be logged in calling function */
                                gf_log (THIS->name, GF_LOG_WARNING,
                                        "failed to write (%s)",
                                        strerror (errno));
                                goto out;
                        }
                }

                size_pending = (size - buf_len);
                if (!size_pending)
                        break;
        }

        ret = size;
out:
        return ret;

}

int32_t
gf_defrag_handle_hardlink (xlator_t *this, loc_t *loc, dict_t  *xattrs,
                           struct iatt *stbuf)
{
        int32_t                 ret             = -1;
        xlator_t               *cached_subvol   = NULL;
        xlator_t               *hashed_subvol   = NULL;
        xlator_t               *linkto_subvol   = NULL;
        data_t                 *data            = NULL;
        struct iatt             iatt            = {0,};
        int32_t                 op_errno        = 0;

        GF_VALIDATE_OR_GOTO ("defrag", loc, out);
        GF_VALIDATE_OR_GOTO ("defrag", loc->name, out);
        GF_VALIDATE_OR_GOTO ("defrag", stbuf, out);
        GF_VALIDATE_OR_GOTO ("defrag", this, out);
        GF_VALIDATE_OR_GOTO ("defrag", xattrs, out);

        if (uuid_is_null (loc->pargfid)) {
                gf_log ("", GF_LOG_ERROR, "loc->pargfid is NULL for "
                        "%s", loc->path);
                goto out;
        }

        if (uuid_is_null (loc->gfid)) {
                gf_log ("", GF_LOG_ERROR, "loc->gfid is NULL for "
                        "%s", loc->path);
                goto out;
        }

        cached_subvol = dht_subvol_get_cached (this, loc->inode);
        if (!cached_subvol) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to get cached subvol"
                        " for %s on %s", loc->name, this->name);
                goto out;
        }

        hashed_subvol = dht_subvol_get_hashed (this, loc);
        if (!hashed_subvol) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to get hashed subvol"
                        " for %s on %s", loc->name, this->name);
                goto out;
        }

        gf_log (this->name, GF_LOG_INFO, "Attempting to migrate hardlink %s "
                "with gfid %s from %s -> %s", loc->name, uuid_utoa (loc->gfid),
                cached_subvol->name, hashed_subvol->name);
        data = dict_get (xattrs, DHT_LINKFILE_KEY);
        /* set linkto on cached -> hashed if not present, else link it */
        if (!data) {
                ret = dict_set_str (xattrs, DHT_LINKFILE_KEY,
                                    hashed_subvol->name);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR, "Failed to set "
                                "linkto xattr in dict for %s", loc->name);
                        goto out;
                }

                ret = syncop_setxattr (cached_subvol, loc, xattrs, 0);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR, "Linkto setxattr "
                                "failed %s -> %s (%s)", cached_subvol->name,
                                loc->name, strerror (errno));
                        goto out;
                }
                goto out;
        } else {
                linkto_subvol = dht_linkfile_subvol (this, NULL, NULL, xattrs);
                if (!linkto_subvol) {
                        gf_log (this->name, GF_LOG_ERROR, "Failed to get "
                                "linkto subvol for %s", loc->name);
                } else {
                        hashed_subvol = linkto_subvol;
                }

                ret = syncop_link (hashed_subvol, loc, loc);
                if  (ret) {
                        op_errno = errno;
                        gf_log (this->name, GF_LOG_ERROR, "link of %s -> %s"
                                " failed on  subvol %s (%s)", loc->name,
                                uuid_utoa(loc->gfid),
                                hashed_subvol->name, strerror (op_errno));
                        if (op_errno != EEXIST)
                                goto out;
                }
        }
        ret = syncop_lookup (hashed_subvol, loc, NULL, &iatt, NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "Failed lookup %s on %s (%s)"
                        , loc->name, hashed_subvol->name, strerror (errno));
                goto out;
        }

        if (iatt.ia_nlink == stbuf->ia_nlink) {
                ret = dht_migrate_file (this, loc, cached_subvol, hashed_subvol,
                                        GF_DHT_MIGRATE_HARDLINK_IN_PROGRESS);
                if (ret)
                        goto out;
        }
        ret = 0;
out:
        return ret;
}


static inline int
__is_file_migratable (xlator_t *this, loc_t *loc,
                      struct iatt *stbuf, dict_t *xattrs, int flags)
{
        int ret = -1;

        if (IA_ISDIR (stbuf->ia_type)) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: migrate-file called on directory", loc->path);
                ret = -1;
                goto out;
        }

        if (flags == GF_DHT_MIGRATE_HARDLINK_IN_PROGRESS) {
                ret = 0;
                goto out;
        }
        if (stbuf->ia_nlink > 1) {
                /* support for decomission */
                if (flags == GF_DHT_MIGRATE_HARDLINK) {
                        ret = gf_defrag_handle_hardlink (this, loc,
                                                         xattrs, stbuf);
                        if (ret) {
                                gf_log (this->name, GF_LOG_WARNING,
                                        "%s: failed to migrate file with link",
                                        loc->path);
                        }
                } else {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: file has hardlinks", loc->path);
                }
                ret = ENOTSUP;
                goto out;
        }

        ret = 0;

out:
        return ret;
}

static inline int
__dht_rebalance_create_dst_file (xlator_t *to, xlator_t *from, loc_t *loc, struct iatt *stbuf,
                                 dict_t *dict, fd_t **dst_fd)
{
        xlator_t *this = NULL;
        int       ret  = -1;
        fd_t     *fd   = NULL;
        struct iatt new_stbuf = {0,};

        this = THIS;

        ret = dict_set_static_bin (dict, "gfid-req", stbuf->ia_gfid, 16);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: failed to set gfid in dict for create", loc->path);
                goto out;
        }

        ret = dict_set_str (dict, DHT_LINKFILE_KEY, from->name);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: failed to set gfid in dict for create", loc->path);
                goto out;
        }

        fd = fd_create (loc->inode, DHT_REBALANCE_PID);
        if (!fd) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: fd create failed (destination) (%s)",
                        loc->path, strerror (errno));
                ret = -1;
                goto out;
        }

        ret = syncop_lookup (to, loc, NULL, &new_stbuf, NULL, NULL);
        if (!ret) {
                /* File exits in the destination, check if gfid matches */
                if (uuid_compare (stbuf->ia_gfid, new_stbuf.ia_gfid) != 0) {
                        gf_log (this->name, GF_LOG_ERROR,
                                "file %s exits in %s with different gfid",
                                loc->path, to->name);
                        fd_unref (fd);
                        goto out;
                }
        }
        if ((ret == -1) && (errno != ENOENT)) {
                /* File exists in destination, but not accessible */
                gf_log (THIS->name, GF_LOG_WARNING,
                        "%s: failed to lookup file (%s)",
                        loc->path, strerror (errno));
                goto out;
        }

        /* Create the destination with LINKFILE mode, and linkto xattr,
           if the linkfile already exists, it will just open the file */
        ret = syncop_create (to, loc, O_RDWR, DHT_LINKFILE_MODE, fd,
                             dict);
        if (ret < 0) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to create %s on %s (%s)",
                        loc->path, to->name, strerror (errno));
                goto out;
        }

        if (dst_fd)
                *dst_fd = fd;

        /* success */
        ret = 0;

out:
        return ret;
}

static inline int
__dht_check_free_space (xlator_t *to, xlator_t *from, loc_t *loc,
                        struct iatt *stbuf, int flag)
{
        struct statvfs  src_statfs = {0,};
        struct statvfs  dst_statfs = {0,};
        int             ret        = -1;
        xlator_t       *this       = NULL;

        this = THIS;

        ret = syncop_statfs (from, loc, &src_statfs);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to get statfs of %s on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        ret = syncop_statfs (to, loc, &dst_statfs);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to get statfs of %s on %s (%s)",
                        loc->path, to->name, strerror (errno));
                goto out;
        }

        /* if force option is given, do not check for space @ dst.
         * Check only if space is avail for the file */
        if (flag != GF_DHT_MIGRATE_DATA)
                goto check_avail_space;

        if (((dst_statfs.f_bavail *
              dst_statfs.f_bsize) / GF_DISK_SECTOR_SIZE) <
            (((src_statfs.f_bavail * src_statfs.f_bsize) /
              GF_DISK_SECTOR_SIZE) - stbuf->ia_blocks)) {
                gf_log (this->name, GF_LOG_WARNING,
                        "data movement attempted from node (%s) with"
                        " higher disk space to a node (%s) with "
                        "lesser disk space (%s)", from->name,
                        to->name, loc->path);

                /* this is not a 'failure', but we don't want to
                   consider this as 'success' too :-/ */
                ret = 1;
                goto out;
        }

check_avail_space:
        if (((dst_statfs.f_bavail * dst_statfs.f_bsize) /
              GF_DISK_SECTOR_SIZE) < stbuf->ia_blocks) {
                gf_log (this->name, GF_LOG_ERROR,
                        "data movement attempted from node (%s) with "
                        "to node (%s) which does not have required free space"
                        " for %s", from->name, to->name, loc->path);
                ret = 1;
                goto out;
        }

        ret = 0;
out:
        return ret;
}

static inline int
__dht_rebalance_migrate_data (xlator_t *from, xlator_t *to, fd_t *src, fd_t *dst,
                             uint64_t ia_size, int hole_exists)
{
        int            ret    = 0;
        int            count  = 0;
        off_t          offset = 0;
        struct iovec  *vector = NULL;
        struct iobref *iobref = NULL;
        uint64_t       total  = 0;
        size_t         read_size = 0;

        /* if file size is '0', no need to enter this loop */
        while (total < ia_size) {
                read_size = (((ia_size - total) > DHT_REBALANCE_BLKSIZE) ?
                             DHT_REBALANCE_BLKSIZE : (ia_size - total));
                ret = syncop_readv (from, src, read_size,
                                    offset, 0, &vector, &count, &iobref);
                if (!ret || (ret < 0)) {
                        break;
                }

                if (hole_exists)
                        ret = dht_write_with_holes (to, dst, vector, count,
                                                    ret, offset, iobref);
                else
                        ret = syncop_writev (to, dst, vector, count,
                                             offset, iobref, 0);
                if (ret < 0) {
                        break;
                }
                offset += ret;
                total += ret;

                if (vector)
                        GF_FREE (vector);
                if (iobref)
                        iobref_unref (iobref);
                iobref = NULL;
                vector = NULL;
        }
        if (iobref)
                iobref_unref (iobref);
        if (vector)
                GF_FREE (vector);

        if (ret >= 0)
                ret = 0;

        return ret;
}


static inline int
__dht_rebalance_open_src_file (xlator_t *from, xlator_t *to, loc_t *loc,
                               struct iatt *stbuf, fd_t **src_fd)
{
        int          ret  = 0;
        fd_t        *fd   = NULL;
        dict_t      *dict = NULL;
        xlator_t    *this = NULL;
        struct iatt  iatt = {0,};

        this = THIS;

        fd = fd_create (loc->inode, DHT_REBALANCE_PID);
        if (!fd) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: fd create failed (source)", loc->path);
                ret = -1;
                goto out;
        }

        ret = syncop_open (from, loc, O_RDWR, fd);
        if (ret == -1) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to open file %s on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        ret = -1;
        dict = dict_new ();
        if (!dict)
                goto out;

        ret = dict_set_str (dict, DHT_LINKFILE_KEY, to->name);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to set xattr in dict for %s (linkto:%s)",
                        loc->path, to->name);
                goto out;
        }

        /* Once the migration starts, the source should have 'linkto' key set
           to show which is the target, so other clients can work around it */
        ret = syncop_setxattr (from, loc, dict, 0);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to set xattr on %s in %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        /* mode should be (+S+T) to indicate migration is in progress */
        iatt.ia_prot = stbuf->ia_prot;
        iatt.ia_type = stbuf->ia_type;
        iatt.ia_prot.sticky = 1;
        iatt.ia_prot.sgid = 1;

        ret = syncop_setattr (from, loc, &iatt, GF_SET_ATTR_MODE, NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to set mode on %s in %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        if (src_fd)
                *src_fd = fd;

        /* success */
        ret = 0;
out:
        if (dict)
                dict_unref (dict);

        return ret;
}

int
migrate_special_files (xlator_t *this, xlator_t *from, xlator_t *to, loc_t *loc,
                       struct iatt *buf)
{
        int          ret      = -1;
        dict_t      *rsp_dict = NULL;
        dict_t      *dict     = NULL;
        char        *link     = NULL;
        struct iatt  stbuf    = {0,};

        dict = dict_new ();
        if (!dict)
                goto out;

        ret = dict_set_int32 (dict, DHT_LINKFILE_KEY, 256);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: failed to set 'linkto' key in dict", loc->path);
                goto out;
        }

        /* check in the destination if the file is link file */
        ret = syncop_lookup (to, loc, dict, &stbuf, &rsp_dict, NULL);
        if ((ret == -1) && (errno != ENOENT)) {
                gf_log (this->name, GF_LOG_WARNING, "%s: lookup failed (%s)",
                        loc->path, strerror (errno));
                goto out;
        }

        /* we no more require this key */
        dict_del (dict, DHT_LINKFILE_KEY);

        /* file exists in target node, only if it is 'linkfile' its valid,
           otherwise, error out */
        if (!ret) {
                if (!check_is_linkfile (loc->inode, &stbuf, rsp_dict)) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: file exists in destination", loc->path);
                        ret = -1;
                        goto out;
                }

                /* as file is linkfile, delete it */
                ret = syncop_unlink (to, loc);
                if (ret) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: failed to delete the linkfile (%s)",
                                loc->path, strerror (errno));
                        goto out;
                }
        }

        /* Set the gfid of the source file in dict */
        ret = dict_set_static_bin (dict, "gfid-req", buf->ia_gfid, 16);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: failed to set gfid in dict for create", loc->path);
                goto out;
        }

        /* Create the file in target */
        if (IA_ISLNK (buf->ia_type)) {
                /* Handle symlinks separately */
                ret = syncop_readlink (from, loc, &link, buf->ia_size);
                if (ret < 0) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: readlink on symlink failed (%s)",
                                loc->path, strerror (errno));
                        goto out;
                }

                ret = syncop_symlink (to, loc, link, dict);
                if (ret) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: creating symlink failed (%s)",
                                loc->path, strerror (errno));
                        goto out;
                }

                goto done;
        }

        ret = syncop_mknod (to, loc, st_mode_from_ia (buf->ia_prot,
                                                      buf->ia_type),
                            makedev (ia_major (buf->ia_rdev),
                                     ia_minor (buf->ia_rdev)), dict);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING, "%s: mknod failed (%s)",
                        loc->path, strerror (errno));
                goto out;
        }

done:
        ret = syncop_unlink (from, loc);
        if (ret)
                gf_log (this->name, GF_LOG_WARNING, "%s: unlink failed (%s)",
                        loc->path, strerror (errno));

out:
        if (dict)
                dict_unref (dict);

        if (rsp_dict)
                dict_unref (rsp_dict);

        return ret;
}

/*
  return values:

   -1 : failure
    0 : successfully migrated data
    1 : not a failure, but we can't migrate data as of now
*/
int
dht_migrate_file (xlator_t *this, loc_t *loc, xlator_t *from, xlator_t *to,
                  int flag)
{
        int             ret            = -1;
        struct iatt     new_stbuf      = {0,};
        struct iatt     stbuf          = {0,};
        struct iatt     empty_iatt     = {0,};
        ia_prot_t       src_ia_prot    = {0,};
        fd_t           *src_fd         = NULL;
        fd_t           *dst_fd         = NULL;
        dict_t         *dict           = NULL;
        dict_t         *xattr          = NULL;
        dict_t         *xattr_rsp      = NULL;
        int             file_has_holes = 0;

        gf_log (this->name, GF_LOG_INFO, "%s: attempting to move from %s to %s",
                loc->path, from->name, to->name);

        dict = dict_new ();
        if (!dict)
                goto out;

        ret = dict_set_int32 (dict, DHT_LINKFILE_KEY, 256);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "%s: failed to set 'linkto' key in dict", loc->path);
                goto out;
        }

        /* Phase 1 - Data migration is in progress from now on */
        ret = syncop_lookup (from, loc, dict, &stbuf, &xattr_rsp, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "%s: lookup failed on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        /* we no more require this key */
        dict_del (dict, DHT_LINKFILE_KEY);

        /* preserve source mode, so set the same to the destination */
        src_ia_prot = stbuf.ia_prot;

        /* Check if file can be migrated */
        ret = __is_file_migratable (this, loc, &stbuf, xattr_rsp, flag);
        if (ret)
                goto out;

        /* Take care of the special files */
        if (!IA_ISREG (stbuf.ia_type)) {
                /* Special files */
                ret = migrate_special_files (this, from, to, loc, &stbuf);
                goto out;
        }

        /* create the destination, with required modes/xattr */
        ret = __dht_rebalance_create_dst_file (to, from, loc, &stbuf,
                                               dict, &dst_fd);
        if (ret)
                goto out;

        ret = __dht_check_free_space (to, from, loc, &stbuf, flag);
        if (ret) {
                goto out;
        }

        /* Open the source, and also update mode/xattr */
        ret = __dht_rebalance_open_src_file (from, to, loc, &stbuf, &src_fd);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "failed to open %s on %s",
                        loc->path, from->name);
                goto out;
        }

        ret = syncop_fstat (from, src_fd, &stbuf);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "failed to lookup %s on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        /* Try to preserve 'holes' while migrating data */
        if (stbuf.ia_size > (stbuf.ia_blocks * GF_DISK_SECTOR_SIZE))
                file_has_holes = 1;

        /* All I/O happens in this function */
        ret = __dht_rebalance_migrate_data (from, to, src_fd, dst_fd,
					    stbuf.ia_size, file_has_holes);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "%s: failed to migrate data",
                        loc->path);
                /* reset the destination back to 0 */
                ret = syncop_ftruncate (to, dst_fd, 0);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR,
                                "%s: failed to reset target size back to 0 (%s)",
                                loc->path, strerror (errno));
                }

                ret = -1;
                goto out;
        }

        /* TODO: move all xattr related operations to fd based operations */
        ret = syncop_listxattr (from, loc, &xattr);
        if (ret == -1)
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to get xattr from %s (%s)",
                        loc->path, from->name, strerror (errno));

        ret = syncop_setxattr (to, loc, xattr, 0);
        if (ret == -1)
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to set xattr on %s (%s)",
                        loc->path, to->name, strerror (errno));

        /* TODO: Sync the locks */

        ret = syncop_fsync (to, dst_fd);
        if (ret)
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to fsync on %s (%s)",
                        loc->path, to->name, strerror (errno));


        /* Phase 2 - Data-Migration Complete, Housekeeping updates pending */

        ret = syncop_fstat (from, src_fd, &new_stbuf);
        if (ret < 0) {
                /* Failed to get the stat info */
                gf_log (this->name, GF_LOG_ERROR,
                        "failed to fstat file %s on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        /* source would have both sticky bit and sgid bit set, reset it to 0,
           and set the source permission on destination, if it was not set
           prior to setting rebalance-modes in source  */
        if (!src_ia_prot.sticky)
                new_stbuf.ia_prot.sticky = 0;

        if (!src_ia_prot.sgid)
                new_stbuf.ia_prot.sgid = 0;

        /* TODO: if the source actually had sticky bit, or sgid bit set,
           we are not handling it */

        ret = syncop_fsetattr (to, dst_fd, &new_stbuf,
                               (GF_SET_ATTR_UID | GF_SET_ATTR_GID |
                                GF_SET_ATTR_MODE), NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to perform setattr on %s (%s)",
                        loc->path, to->name, strerror (errno));
                goto out;
        }

        /* Because 'futimes' is not portable */
        ret = syncop_setattr (to, loc, &new_stbuf,
                              (GF_SET_ATTR_MTIME | GF_SET_ATTR_ATIME),
                              NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to perform setattr on %s (%s)",
                        loc->path, to->name, strerror (errno));
        }

        /* Make the source as a linkfile first before deleting it */
        empty_iatt.ia_prot.sticky = 1;
        ret = syncop_fsetattr (from, src_fd, &empty_iatt,
                               GF_SET_ATTR_MODE, NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,             \
                        "%s: failed to perform setattr on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        /* Do a stat and check the gfid before unlink */
        ret = syncop_stat (from, loc, &empty_iatt);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to do a stat on %s (%s)",
                        loc->path, from->name, strerror (errno));
                goto out;
        }

        if (uuid_compare (empty_iatt.ia_gfid, loc->gfid) == 0) {
                /* take out the source from namespace */
                ret = syncop_unlink (from, loc);
                if (ret) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: failed to perform unlink on %s (%s)",
                                loc->path, from->name, strerror (errno));
                        goto out;
                }
        }

        /* Free up the data blocks on the source node, as the whole
           file is migrated */
        ret = syncop_ftruncate (from, src_fd, 0);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to perform truncate on %s (%s)",
                        loc->path, from->name, strerror (errno));
        }

        /* remove the 'linkto' xattr from the destination */
        ret = syncop_fremovexattr (to, dst_fd, DHT_LINKFILE_KEY);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING,
                        "%s: failed to perform removexattr on %s (%s)",
                        loc->path, to->name, strerror (errno));
        }

        ret = syncop_lookup (this, loc, NULL, NULL, NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_DEBUG,
                        "%s: failed to lookup the file on subvolumes (%s)",
                        loc->path, strerror (errno));
        }

        gf_log (this->name, GF_LOG_INFO,
                "completed migration of %s from subvolume %s to %s",
                loc->path, from->name, to->name);

        ret = 0;
out:
        if (dict)
                dict_unref (dict);

        if (xattr)
                dict_unref (xattr);
        if (xattr_rsp)
                dict_unref (xattr_rsp);

        if (dst_fd)
                syncop_close (dst_fd);
        if (src_fd)
                syncop_close (src_fd);

        return ret;
}

static int
rebalance_task (void *data)
{
        int           ret   = -1;
        dht_local_t  *local = NULL;
        call_frame_t *frame = NULL;

        frame = data;

        local = frame->local;

        /* This function is 'synchrounous', hence if it returns,
           we are done with the task */
        ret = dht_migrate_file (THIS, &local->loc, local->rebalance.from_subvol,
                                local->rebalance.target_node, local->flags);

        return ret;
}

static int
rebalance_task_completion (int op_ret, call_frame_t *sync_frame, void *data)
{
        int           ret        = -1;
        uint64_t      layout_int = 0;
        dht_layout_t *layout     = 0;
        xlator_t     *this       = NULL;
        dht_local_t  *local      = NULL;
        int32_t       op_errno   = EINVAL;

        this = THIS;
        local = sync_frame->local;

        if (!op_ret) {
                /* Make sure we have valid 'layout' in inode ctx
                   after the operation */
                ret = inode_ctx_del (local->loc.inode, this, &layout_int);
                if (!ret && layout_int) {
                        layout = (dht_layout_t *)(long)layout_int;
                        dht_layout_unref (this, layout);
                }

                ret = dht_layout_preset (this, local->rebalance.target_node,
                                         local->loc.inode);
                if (ret)
                        gf_log (this->name, GF_LOG_WARNING,
                                "%s: failed to set inode ctx", local->loc.path);
        }

        if (op_ret == -1) {
                /* Failure of migration process, mostly due to write process.
                   as we can't preserve the exact errno, lets say there was
                   no space to migrate-data
                */
                op_errno = ENOSPC;
        }

        if (op_ret == 1) {
                /* migration didn't happen, but is not a failure, let the user
                   understand that he doesn't have permission to migrate the
                   file.
                */
                op_ret = -1;
                op_errno = EPERM;
        }

        DHT_STACK_UNWIND (setxattr, sync_frame, op_ret, op_errno, NULL);
        return 0;
}

int
dht_start_rebalance_task (xlator_t *this, call_frame_t *frame)
{
        int         ret     = -1;

        ret = synctask_new (this->ctx->env, rebalance_task,
                            rebalance_task_completion,
                            frame, frame);
        return ret;
}

int
gf_listener_stop (void)
{
        glusterfs_ctx_t  *ctx = NULL;
        cmd_args_t       *cmd_args = NULL;
        int              ret = 0;
        xlator_t         *this = NULL;

        ctx = glusterfs_ctx_get ();
        GF_ASSERT (ctx);
        cmd_args = &ctx->cmd_args;
        if (cmd_args->sock_file) {
                ret = unlink (cmd_args->sock_file);
                if (ret && (ENOENT == errno)) {
                        ret = 0;
                }
        }

        if (ret) {
                this = THIS;
                gf_log (this->name, GF_LOG_ERROR, "Failed to unlink listener "
                        "socket %s, error: %s", cmd_args->sock_file,
                        strerror (errno));
        }
        return ret;
}

void
dht_build_root_inode (xlator_t *this, inode_t **inode)
{
        inode_table_t    *itable        = NULL;
        uuid_t            root_gfid     = {0, };

        itable = inode_table_new (0, this);
        if (!itable)
                return;

        root_gfid[15] = 1;
        *inode = inode_find (itable, root_gfid);
}

void
dht_build_root_loc (inode_t *inode, loc_t *loc)
{
        loc->path = "/";
        loc->inode = inode;
        loc->inode->ia_type = IA_IFDIR;
        memset (loc->gfid, 0, 16);
        loc->gfid[15] = 1;
}


/* return values: 1 -> error, bug ignore and continue
                  0 -> proceed
                 -1 -> error, handle it */
int32_t
gf_defrag_handle_migrate_error (int32_t op_errno, gf_defrag_info_t *defrag)
{
        /* if errno is not ENOSPC or ENOTCONN, we can still continue
           with rebalance process */
        if ((errno != ENOSPC) || (errno != ENOTCONN))
                return 1;

        if (errno == ENOTCONN) {
                /* Most probably mount point went missing (mostly due
                   to a brick down), say rebalance failure to user,
                   let him restart it if everything is fine */
                defrag->defrag_status = GF_DEFRAG_STATUS_FAILED;
                return -1;
        }

        if (errno == ENOSPC) {
                /* rebalance process itself failed, may be
                   remote brick went down, or write failed due to
                   disk full etc etc.. */
                defrag->defrag_status = GF_DEFRAG_STATUS_FAILED;
                return -1;
        }

        return 0;
}

/* We do a depth first traversal of directories. But before we move into
 * subdirs, we complete the data migration of those directories whose layouts
 * have been fixed
 */

int
gf_defrag_migrate_data (xlator_t *this, gf_defrag_info_t *defrag, loc_t *loc,
                        dict_t *migrate_data)
{
        int                      ret            = -1;
        loc_t                    entry_loc      = {0,};
        fd_t                    *fd             = NULL;
        gf_dirent_t              entries;
        gf_dirent_t             *tmp            = NULL;
        gf_dirent_t             *entry          = NULL;
        gf_boolean_t             free_entries   = _gf_false;
        off_t                    offset         = 0;
        dict_t                  *dict           = NULL;
        struct iatt              iatt           = {0,};
        int32_t                  op_errno       = 0;
        char                    *uuid_str       = NULL;
        uuid_t                   node_uuid      = {0,};
        int                      readdir_operrno = 0;

        gf_log (this->name, GF_LOG_INFO, "migrate data called on %s",
                loc->path);
        fd = fd_create (loc->inode, defrag->pid);
        if (!fd) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to create fd");
                goto out;
        }

        ret = syncop_opendir (this, loc, fd);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to open dir %s",
                        loc->path);
                goto out;
        }

        INIT_LIST_HEAD (&entries.list);

        while ((ret = syncop_readdirp (this, fd, 131072, offset, NULL,
                                       &entries)) != 0) {
                if (ret < 0)
                        break;

                /* Need to keep track of ENOENT errno, that means, there is no
                   need to send more readdirp() */
                readdir_operrno = errno;

                free_entries = _gf_true;

                if (list_empty (&entries.list))
                        break;
                list_for_each_entry_safe (entry, tmp, &entries.list, list) {
                        if (defrag->defrag_status != GF_DEFRAG_STATUS_STARTED) {
                                ret = 1;
                                goto out;
                        }

                        offset = entry->d_off;

                        if (!strcmp (entry->d_name, ".") ||
                            !strcmp (entry->d_name, ".."))
                                continue;

                        if (IA_ISDIR (entry->d_stat.ia_type))
                                continue;

                        defrag->num_files_lookedup++;

                        loc_wipe (&entry_loc);
                        ret =dht_build_child_loc (this, &entry_loc, loc,
                                                  entry->d_name);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "Child loc"
                                        " build failed");
                                goto out;
                        }

                        if (uuid_is_null (entry->d_stat.ia_gfid)) {
                                gf_log (this->name, GF_LOG_ERROR, "%s/%s"
                                        " gfid not present", loc->path,
                                         entry->d_name);
                                continue;
                        }

                        uuid_copy (entry_loc.gfid, entry->d_stat.ia_gfid);

                        if (uuid_is_null (loc->gfid)) {
                                gf_log (this->name, GF_LOG_ERROR, "%s/%s"
                                        " gfid not present", loc->path,
                                         entry->d_name);
                                continue;
                        }

                        uuid_copy (entry_loc.pargfid, loc->gfid);

                        entry_loc.inode->ia_type = entry->d_stat.ia_type;

                        ret = syncop_lookup (this, &entry_loc, NULL, &iatt,
                                             NULL, NULL);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "%s"
                                        " lookup failed", entry_loc.path);
                                continue;
                        }

                        ret = syncop_getxattr (this, &entry_loc, &dict,
                                               GF_XATTR_NODE_UUID_KEY);
                        if(ret < 0) {
                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
                                        "get node-uuid for %s", entry_loc.path);
                                continue;
                        }

                        ret = dict_get_str (dict, GF_XATTR_NODE_UUID_KEY,
                                            &uuid_str);
                        if(ret < 0) {
                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
                                        "get node-uuid from dict for %s",
                                        entry_loc.path);
                                continue;
                        }

                        if (uuid_parse (uuid_str, node_uuid)) {
                                gf_log (this->name, GF_LOG_ERROR, "uuid_parse "
                                        "failed for %s", entry_loc.path);
                                continue;
                        }

                        /* if file belongs to different node, skip migration
                         * the other node will take responsibility of migration
                         */
                        if (uuid_compare (node_uuid, defrag->node_uuid)) {
                                gf_log (this->name, GF_LOG_TRACE, "%s does not"
                                        "belong to this node", entry_loc.path);
                                continue;
                        }

                        uuid_str = NULL;

                        dict_del (dict, GF_XATTR_NODE_UUID_KEY);


                        /* if distribute is present, it will honor this key.
                         * -1 is returned if distribute is not present or file
                         * doesn't have a link-file. If file has link-file, the
                         * path of link-file will be the value, and also that
                         * guarantees that file has to be mostly migrated */

                        ret = syncop_getxattr (this, &entry_loc, &dict,
                                               GF_XATTR_LINKINFO_KEY);
                        if (ret < 0) {
                                gf_log (this->name, GF_LOG_TRACE, "failed to "
                                        "get link-to key for %s",
                                        entry_loc.path);
                                continue;
                        }

                        ret = syncop_setxattr (this, &entry_loc, migrate_data,
                                               0);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "migrate-data"
                                        " failed for %s", entry_loc.path);
                                defrag->total_failures +=1;
                        }

                        if (ret == -1) {
                                op_errno = errno;
                                ret = gf_defrag_handle_migrate_error (op_errno,
                                                                      defrag);

                                if (!ret)
                                        gf_log (this->name, GF_LOG_DEBUG,
                                                "migrate-data on %s failed: %s",
                                                entry_loc.path,
                                                strerror (op_errno));
                                else if (ret == 1)
                                        continue;
                                else if (ret == -1)
                                        goto out;
                        }

                        LOCK (&defrag->lock);
                        {
                                defrag->total_files += 1;
                                defrag->total_data += iatt.ia_size;
                        }
                        UNLOCK (&defrag->lock);
                }

                gf_dirent_free (&entries);
                free_entries = _gf_false;
                INIT_LIST_HEAD (&entries.list);

                if (readdir_operrno == ENOENT)
                        break;
        }
        ret = 0;
out:
        if (free_entries)
                gf_dirent_free (&entries);

        loc_wipe (&entry_loc);

        if (dict)
                dict_unref(dict);

        if (fd)
                fd_unref (fd);
        return ret;

}


int
gf_defrag_fix_layout (xlator_t *this, gf_defrag_info_t *defrag, loc_t *loc,
                  dict_t *fix_layout, dict_t *migrate_data)
{
        int                      ret            = -1;
        loc_t                    entry_loc      = {0,};
        fd_t                    *fd             = NULL;
        gf_dirent_t              entries;
        gf_dirent_t             *tmp            = NULL;
        gf_dirent_t             *entry          = NULL;
        gf_boolean_t             free_entries   = _gf_false;
        dict_t                  *dict           = NULL;
        off_t                    offset         = 0;
        struct iatt              iatt           = {0,};

        ret = syncop_lookup (this, loc, NULL, &iatt, NULL, NULL);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "Lookup failed on %s",
                        loc->path);
                goto out;
        }

        if (defrag->cmd != GF_DEFRAG_CMD_START_LAYOUT_FIX) {
                ret = gf_defrag_migrate_data (this, defrag, loc, migrate_data);
                if (ret)
                        goto out;
        }

        gf_log (this->name, GF_LOG_TRACE, "fix layout called on %s", loc->path);

        fd = fd_create (loc->inode, defrag->pid);
        if (!fd) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to create fd");
                ret = -1;
                goto out;
        }

        ret = syncop_opendir (this, loc, fd);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to open dir %s",
                        loc->path);
                ret = -1;
                goto out;
        }

        INIT_LIST_HEAD (&entries.list);
        while ((ret = syncop_readdirp (this, fd, 131072, offset, NULL,
                &entries)) != 0)
        {
                if ((ret < 0) || (ret && (errno == ENOENT)))
                        break;
                free_entries = _gf_true;

                if (list_empty (&entries.list))
                        break;
                list_for_each_entry_safe (entry, tmp, &entries.list, list) {
                        if (defrag->defrag_status != GF_DEFRAG_STATUS_STARTED) {
                                ret = 1;
                                goto out;
                        }

                        offset = entry->d_off;

                        if (!strcmp (entry->d_name, ".") ||
                            !strcmp (entry->d_name, ".."))
                                continue;

                        if (!IA_ISDIR (entry->d_stat.ia_type))
                                continue;

                        loc_wipe (&entry_loc);
                        ret =dht_build_child_loc (this, &entry_loc, loc,
                                                  entry->d_name);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "Child loc"
                                        " build failed");
                                goto out;
                        }

                        if (uuid_is_null (entry->d_stat.ia_gfid)) {
                                gf_log (this->name, GF_LOG_ERROR, "%s/%s"
                                        "gfid not present", loc->path,
                                         entry->d_name);
                                continue;
                        }

                        entry_loc.inode->ia_type = entry->d_stat.ia_type;

                        uuid_copy (entry_loc.gfid, entry->d_stat.ia_gfid);
                        if (uuid_is_null (loc->gfid)) {
                                gf_log (this->name, GF_LOG_ERROR, "%s/%s"
                                        "gfid not present", loc->path,
                                         entry->d_name);
                                continue;
                        }

                        uuid_copy (entry_loc.pargfid, loc->gfid);

                        ret = syncop_lookup (this, &entry_loc, NULL, &iatt,
                                             NULL, NULL);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "%s"
                                        " lookup failed", entry_loc.path);
                                continue;
                        }

                        ret = syncop_setxattr (this, &entry_loc, fix_layout,
                                               0);
                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "Setxattr "
                                        "failed for %s", entry_loc.path);
                                defrag->defrag_status =
                                GF_DEFRAG_STATUS_FAILED;
                                goto out;
                        }
                        ret = gf_defrag_fix_layout (this, defrag, &entry_loc,
                                                    fix_layout, migrate_data);

                        if (ret) {
                                gf_log (this->name, GF_LOG_ERROR, "Fix layout "
                                        "failed for %s", entry_loc.path);
                                goto out;
                        }

                }
                gf_dirent_free (&entries);
                free_entries = _gf_false;
                INIT_LIST_HEAD (&entries.list);
        }

        ret = 0;
out:
        if (free_entries)
                gf_dirent_free (&entries);

        loc_wipe (&entry_loc);

        if (dict)
                dict_unref(dict);

        if (fd)
                fd_unref (fd);

        return ret;

}


int
gf_defrag_start_crawl (void *data)
{
        xlator_t                *this   = NULL;
        dht_conf_t              *conf   = NULL;
        gf_defrag_info_t        *defrag = NULL;
        int                      ret    = -1;
        loc_t                    loc    = {0,};
        struct iatt              iatt   = {0,};
        struct iatt              parent = {0,};
        dict_t                  *fix_layout = NULL;
        dict_t                  *migrate_data = NULL;
        dict_t                  *status = NULL;

        this = data;
        if (!this)
                goto out;

        conf = this->private;
        if (!conf)
                goto out;

        defrag = conf->defrag;
        if (!defrag)
                goto out;
        dht_build_root_inode (this, &defrag->root_inode);
        if (!defrag->root_inode)
                goto out;

        dht_build_root_loc (defrag->root_inode, &loc);

        /* fix-layout on '/' first */

        ret = syncop_lookup (this, &loc, NULL, &iatt, NULL, &parent);

        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "look up on / failed");
                goto out;
        }

        fix_layout = dict_new ();
        if (!fix_layout) {
                ret = -1;
                goto out;
        }

        ret = dict_set_str (fix_layout, GF_XATTR_FIX_LAYOUT_KEY, "yes");
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "Failed to set dict str");
                goto out;
        }

        ret = syncop_setxattr (this, &loc, fix_layout, 0);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "fix layout on %s failed",
                        loc.path);
                goto out;
        }

        if (defrag->cmd != GF_DEFRAG_CMD_START_LAYOUT_FIX) {
                migrate_data = dict_new ();
                if (!migrate_data) {
                        ret = -1;
                        goto out;
                }
                if (defrag->cmd == GF_DEFRAG_CMD_START_FORCE)
                        ret = dict_set_str (migrate_data,
                                            "distribute.migrate-data", "force");
                else
                        ret = dict_set_str (migrate_data,
                                            "distribute.migrate-data",
                                            "non-force");
                if (ret)
                        goto out;
        }
        ret = gf_defrag_fix_layout (this, defrag, &loc, fix_layout,
                                    migrate_data);
        if ((defrag->defrag_status != GF_DEFRAG_STATUS_STOPPED) &&
            (defrag->defrag_status != GF_DEFRAG_STATUS_FAILED)) {
                defrag->defrag_status = GF_DEFRAG_STATUS_COMPLETE;
        }



out:
        LOCK (&defrag->lock);
        {
                status = dict_new ();
                gf_defrag_status_get (defrag, status);
                glusterfs_rebalance_event_notify (status);
                if (status)
                        dict_unref (status);
                defrag->is_exiting = 1;
        }
        UNLOCK (&defrag->lock);

        if (defrag)
                GF_FREE (defrag);

        return ret;
}


static int
gf_defrag_done  (int ret, call_frame_t *sync_frame, void *data)
{
        gf_listener_stop();

        GF_FREE (data);
        STACK_DESTROY (sync_frame->root);
        kill (getpid(), SIGTERM);
        return 0;
}

void *
gf_defrag_start (void *data)
{
        int                      ret    = -1;
        call_frame_t            *frame  = NULL;
        dht_conf_t              *conf   = NULL;
        gf_defrag_info_t        *defrag = NULL;
        xlator_t                *this  = NULL;

        this = data;
        conf = this->private;
        if (!conf)
                goto out;

        defrag = conf->defrag;
        if (!defrag)
                goto out;

        frame = create_frame (this, this->ctx->pool);
        if (!frame)
                goto out;

        frame->root->pid = GF_CLIENT_PID_DEFRAG;

        defrag->pid = frame->root->pid;

        defrag->defrag_status = GF_DEFRAG_STATUS_STARTED;

        ret = synctask_new (this->ctx->env, gf_defrag_start_crawl,
                            gf_defrag_done, frame, this);

        if (ret)
                gf_log (this->name, GF_LOG_ERROR, "Could not create"
                        " task for rebalance");
out:
        return NULL;
}

int
gf_defrag_status_get (gf_defrag_info_t *defrag, dict_t *dict)
{
        int      ret    = 0;
        uint64_t files  = 0;
        uint64_t size   = 0;
        uint64_t lookup = 0;
        uint64_t failures = 0;
        char     *status = "";

        if (!defrag)
                goto out;

        ret = 0;
        if (defrag->defrag_status == GF_DEFRAG_STATUS_NOT_STARTED)
                goto out;

        files  = defrag->total_files;
        size   = defrag->total_data;
        lookup = defrag->num_files_lookedup;
        failures = defrag->total_failures;

        if (!dict)
                goto log;

        ret = dict_set_uint64 (dict, "files", files);
        if (ret)
                gf_log (THIS->name, GF_LOG_WARNING,
                        "failed to set file count");

        ret = dict_set_uint64 (dict, "size", size);
        if (ret)
                gf_log (THIS->name, GF_LOG_WARNING,
                        "failed to set size of xfer");

        ret = dict_set_uint64 (dict, "lookups", lookup);
        if (ret)
                gf_log (THIS->name, GF_LOG_WARNING,
                        "failed to set lookedup file count");

        ret = dict_set_int32 (dict, "status", defrag->defrag_status);
        if (ret)
                gf_log (THIS->name, GF_LOG_WARNING,
                        "failed to set status");

        ret = dict_set_uint64 (dict, "failures", failures);
log:
        switch (defrag->defrag_status) {
        case GF_DEFRAG_STATUS_NOT_STARTED:
                status = "not started";
                break;
        case GF_DEFRAG_STATUS_STARTED:
                status = "in progress";
                break;
        case GF_DEFRAG_STATUS_STOPPED:
                status = "stopped";
                break;
        case GF_DEFRAG_STATUS_COMPLETE:
                status = "completed";
                break;
        case GF_DEFRAG_STATUS_FAILED:
                status = "failed";
                break;
        }

        gf_log (THIS->name, GF_LOG_INFO, "Rebalance is %s", status);
        gf_log (THIS->name, GF_LOG_INFO, "Files migrated: %"PRIu64", size: %"
                PRIu64", lookups: %"PRIu64", failures: %"PRIu64, files, size,
                lookup, failures);


out:
        return 0;
}

int
gf_defrag_stop (gf_defrag_info_t *defrag, dict_t *output)
{
        /* TODO: set a variable 'stop_defrag' here, it should be checked
           in defrag loop */
        int     ret = -1;
        GF_ASSERT (defrag);

        if (defrag->defrag_status == GF_DEFRAG_STATUS_NOT_STARTED) {
                goto out;
        }

        gf_log ("", GF_LOG_INFO, "Recieved stop command on rebalance");
        defrag->defrag_status = GF_DEFRAG_STATUS_STOPPED;

        if (output)
                gf_defrag_status_get (defrag, output);
        ret = 0;
out:
        gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
        return ret;
}