summaryrefslogtreecommitdiffstats
path: root/xlators/features/snapview-server/src/snapview-server.c
blob: 8921909d7ee08c9e293c761b92d7b08997bd346a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
/*
   Copyright (c) 2014 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 "snapview-server.h"
#include "snapview-server-mem-types.h"

#include "xlator.h"
#include "rpc-clnt.h"
#include "xdr-generic.h"
#include "protocol-common.h"
#include "syscall.h"
#include <pthread.h>


int32_t
svs_lookup_entry_point (xlator_t *this, loc_t *loc, inode_t *parent,
                        struct iatt *buf, struct iatt *postparent,
                        int32_t *op_errno)
{
        uuid_t         gfid;
        svs_inode_t   *inode_ctx = NULL;
        int            op_ret    = -1;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);
        GF_VALIDATE_OR_GOTO (this->name, postparent, out);

        if (uuid_is_null (loc->inode->gfid)) {
                uuid_generate (gfid);
                svs_iatt_fill (gfid, buf);

                /* Here the inode context of the entry point directory
                   is filled with just the type of the inode and the gfid
                   of the parent from where the entry point was entered.
                   The glfs object and the fs instance will be NULL.
                */
                if (parent)
                        svs_iatt_fill (parent->gfid, postparent);
                else {
                        svs_iatt_fill (buf->ia_gfid, postparent);
                }

                inode_ctx = svs_inode_ctx_get_or_new (this, loc->inode);
                if (!inode_ctx) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to "
                                "allocate inode context for entry point "
                                "directory");
                        op_ret = -1;
                        *op_errno = ENOMEM;
                        goto out;
                }
                uuid_copy (inode_ctx->pargfid, loc->pargfid);
                memcpy (&inode_ctx->buf, buf, sizeof (*buf));
                inode_ctx->type = SNAP_VIEW_ENTRY_POINT_INODE;
        } else {
                if (inode_ctx) {
                        memcpy (buf, &inode_ctx->buf, sizeof (*buf));
                        svs_iatt_fill (inode_ctx->pargfid, postparent);
                } else {
                        svs_iatt_fill (loc->inode->gfid, buf);
                        if (parent)
                                svs_iatt_fill (parent->gfid,
                                               postparent);
                        else {
                                svs_iatt_fill (loc->inode->gfid,
                                               postparent);
                        }
                }
        }

        op_ret = 0;

out:
        return op_ret;
}

/* When lookup comes from client and the protocol/server tries to resolve
   the pargfid via just sending the gfid as part of lookup, if the inode
   for the parent gfid is not found. But since that gfid has not yet been
   looked  up yet, inode will not be having inode context and parent is not
   there (as it is the parent of the entry that is being resolved). So
   without parent and inode context, svs cannot know which snapshot
   to look into. In such cases, the amguity is handled by looking
   into the latest snapshot. If the directory is there in the latest
   snapshot, lookup is successful, otherwise it is a failure. So for
   any directory created after taking the latest snapshot, entry into
   snapshot world is denied. i.e you have to be part of snapshot world
   to enter it. If the gfid is not found there, then unwind with
   ESTALE
   This gets executed mainly in the situation where the snapshot entry
   point is entered from a non-root directory and that non-root directory's
   inode (or gfid) is not yet looked up. And in each case when a gfid has to
   be looked up (without any inode contex and parent context present), last
   snapshot is referred and a random gfid is not generated.
*/
int32_t
svs_lookup_gfid (xlator_t *this, loc_t *loc, struct iatt *buf,
                 struct iatt *postparent, int32_t *op_errno)
{
        int32_t         op_ret                          = -1;
        unsigned char   handle_obj[GFAPI_HANDLE_LENGTH] = {0, };
        glfs_t         *fs                              = NULL;
        glfs_object_t  *object                          = NULL;
        struct stat     statbuf                         = {0, };
        svs_inode_t    *inode_ctx                       = NULL;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);
        GF_VALIDATE_OR_GOTO (this->name, postparent, out);

        if (uuid_is_null (loc->gfid) && uuid_is_null (loc->inode->gfid)) {
                gf_log (this->name, GF_LOG_ERROR, "gfid is NULL");
                goto out;
        }

        if (!uuid_is_null (loc->inode->gfid))
                memcpy (handle_obj, loc->inode->gfid,
                        GFAPI_HANDLE_LENGTH);
        else
                memcpy (handle_obj, loc->gfid,
                        GFAPI_HANDLE_LENGTH);

        fs = svs_get_latest_snapshot (this);
        if (!fs) {
                gf_log (this->name, GF_LOG_ERROR, "failed to get the latest "
                        "snapshot");
                op_ret = -1;
                *op_errno = EINVAL;
                goto out;
        }


        object = glfs_h_create_from_handle (fs, handle_obj, GFAPI_HANDLE_LENGTH,
                                            &statbuf);
        if (!object) {
                gf_log (this->name, GF_LOG_ERROR, "failed to do lookup and get "
                        "the handle on the snapshot %s (path: %s, gfid: %s)",
                        loc->name, loc->path, uuid_utoa (loc->gfid));
                op_ret = -1;
                *op_errno = ESTALE;
                goto out;
        }

        inode_ctx = svs_inode_ctx_get_or_new (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "failed to allocate inode "
                        "context");
                op_ret = -1;
                *op_errno = ENOMEM;
                goto out;
        }

        iatt_from_stat (buf, &statbuf);
        if (!uuid_is_null (loc->gfid))
                uuid_copy (buf->ia_gfid, loc->gfid);
        else
                uuid_copy (buf->ia_gfid, loc->inode->gfid);

        inode_ctx->type = SNAP_VIEW_VIRTUAL_INODE;
        inode_ctx->fs = fs;
        inode_ctx->object = object;
        memcpy (&inode_ctx->buf, buf, sizeof (*buf));
        svs_iatt_fill (buf->ia_gfid, postparent);

        op_ret = 0;

out:
        return op_ret;
}

/* If the parent is an entry point inode, then create the handle for the
   snapshot on which lookup came. i.e in reality lookup came on
   the directory from which the entry point directory was entered, but
   lookup is into the past. So create the handle for it by doing
   the name-less lookup on the gfid (which can be obtained from
   parent's context
*/
int32_t
svs_lookup_snapshot (xlator_t *this, loc_t *loc, struct iatt *buf,
                     struct iatt *postparent, inode_t *parent,
                     svs_inode_t *parent_ctx, int32_t *op_errno)
{
        int32_t         op_ret                          = -1;
        unsigned char   handle_obj[GFAPI_HANDLE_LENGTH] = {0, };
        glfs_t         *fs                              = NULL;
        glfs_object_t  *object                          = NULL;
        struct stat     statbuf                         = {0, };
        svs_inode_t    *inode_ctx                       = NULL;
        uuid_t          gfid;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);
        GF_VALIDATE_OR_GOTO (this->name, postparent, out);
        GF_VALIDATE_OR_GOTO (this->name, parent_ctx, out);
        GF_VALIDATE_OR_GOTO (this->name, parent, out);

        fs = svs_initialise_snapshot_volume (this, loc->name);
        if (!fs) {
                gf_log (this->name, GF_LOG_ERROR, "failed to "
                        "create the fs instance for snap %s",
                        loc->name);
                op_ret = -1;
                *op_errno = ESTALE;
                goto out;
        }

        memcpy (handle_obj, parent_ctx->pargfid,
                GFAPI_HANDLE_LENGTH);
        object = glfs_h_create_from_handle (fs, handle_obj, GFAPI_HANDLE_LENGTH,
                                            &statbuf);
        if (!object) {
                gf_log (this->name, GF_LOG_ERROR, "failed to do lookup and "
                        "get the handle on the snapshot %s", loc->name);
                op_ret = -1;
                *op_errno = errno;
                goto out;
        }

        inode_ctx = svs_inode_ctx_get_or_new (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "failed to "
                        "allocate inode context");
                op_ret = -1;
                *op_errno = ENOMEM;
                goto out;
        }

        if (uuid_is_null (loc->gfid) &&
            uuid_is_null (loc->inode->gfid))
                uuid_generate (gfid);
        else {
                if (!uuid_is_null (loc->inode->gfid))
                        uuid_copy (gfid, loc->inode->gfid);
                else
                        uuid_copy (gfid, loc->gfid);
        }
        iatt_from_stat (buf, &statbuf);
        uuid_copy (buf->ia_gfid, gfid);
        svs_fill_ino_from_gfid (buf);
        inode_ctx->type = SNAP_VIEW_SNAPSHOT_INODE;
        inode_ctx->fs = fs;
        inode_ctx->object = object;
        memcpy (&inode_ctx->buf, buf, sizeof (*buf));
        svs_iatt_fill (parent->gfid, postparent);

        op_ret = 0;

out:
        return op_ret;
}

/* Both parent and entry are from snapshot world */
int32_t
svs_lookup_entry (xlator_t *this, loc_t *loc, struct iatt *buf,
                  struct iatt *postparent, inode_t *parent,
                  svs_inode_t *parent_ctx, int32_t *op_errno)
{
        int32_t         op_ret                          = -1;
        glfs_t         *fs                              = NULL;
        glfs_object_t  *object                          = NULL;
        struct stat     statbuf                         = {0, };
        svs_inode_t    *inode_ctx                       = NULL;
        glfs_object_t  *parent_object                   = NULL;
        uuid_t          gfid;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);
        GF_VALIDATE_OR_GOTO (this->name, postparent, out);
        GF_VALIDATE_OR_GOTO (this->name, parent_ctx, out);
        GF_VALIDATE_OR_GOTO (this->name, parent, out);

        parent_object = parent_ctx->object;
        fs = parent_ctx->fs;

        object = glfs_h_lookupat (fs, parent_object, loc->name,
                                  &statbuf);
        if (!object) {
                gf_log (this->name, GF_LOG_ERROR, "failed to do lookup and "
                        "get the handle for entry %s (path: %s)", loc->name,
                        loc->path);
                op_ret = -1;
                *op_errno = errno;
                goto out;
        }

        inode_ctx = svs_inode_ctx_get_or_new (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "failed to "
                        "allocate inode context");
                op_ret = -1;
                *op_errno = ENOMEM;
                goto out;
        }

        if (uuid_is_null (loc->gfid) &&
            uuid_is_null (loc->inode->gfid))
                uuid_generate (gfid);
        else {
                if (!uuid_is_null (loc->inode->gfid))
                        uuid_copy (gfid, loc->inode->gfid);
                else
                        uuid_copy (gfid, loc->gfid);
        }

        iatt_from_stat (buf, &statbuf);
        uuid_copy (buf->ia_gfid, gfid);
        svs_fill_ino_from_gfid (buf);
        inode_ctx->type = SNAP_VIEW_VIRTUAL_INODE;
        inode_ctx->fs = fs;
        inode_ctx->object = object;
        memcpy (&inode_ctx->buf, buf, sizeof (*buf));
        svs_iatt_fill (parent->gfid, postparent);

        op_ret = 0;

out:
        return op_ret;
}

/* inode context is there means lookup has come on an object which was
   built either as part of lookup or as part of readdirp. But in readdirp
   we would not have got the handle to access the object in the gfapi
   world.
   So if inode context contains glfs_t instance for the right
   gfapi world and glfs_object_t handle for accessing it in the gfapi
   world, then unwind with success as the snapshots as of now are
   read-only.
   If the above condition is not met, then send lookup call again to
   the gfapi world. It can happen only if both parent context and
   the name of the entry are present.

   If parent is an entry point to snapshot world:
   * parent is needed for getting the gfid on which lookup has to be done
     (the gfid present in the inode is a virtual gfid) in the snapshot
     world.
   * name is required to get the right glfs_t instance on which lookup
     has to be done

   If parent is a directory from snapshot world:
   * parent context is needed to get the glfs_t instance and to get the
     handle to parent directory in the snapshot world.
   * name is needed to do the lookup on the right entry in the snapshot
     world
*/
int32_t
svs_revalidate (xlator_t *this, loc_t *loc, inode_t *parent,
                svs_inode_t *inode_ctx, svs_inode_t *parent_ctx,
                struct iatt *buf, struct iatt *postparent, int32_t *op_errno)
{
        int32_t         op_ret                          = -1;
        int             ret                             = -1;
        char            tmp_uuid[64]                    = {0, };
        glfs_t         *fs                              = NULL;
        glfs_object_t  *object                          = NULL;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);
        GF_VALIDATE_OR_GOTO (this->name, postparent, out);
        GF_VALIDATE_OR_GOTO (this->name, inode_ctx, out);

        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                svs_iatt_fill (loc->inode->gfid, buf);
                if (parent)
                        svs_iatt_fill (parent->gfid,
                                       postparent);
                else
                        svs_iatt_fill (loc->inode->gfid, postparent);
                op_ret = 0;
                goto out;
        } else {
                /* Though fs and object are present in the inode context, its
                 * better to check if fs is valid or not before doing anything.
                 * Its for the protection from the following operations.
                 * 1) Create a file on the glusterfs mount point
                 * 2) Create a snapshot (say "snap1")
                 * 3) Access the contents of the snapshot
                 * 4) Delete the file from the mount point
                 * 5) Delete the snapshot "snap1"
                 * 6) Create a new snapshot "snap1"
                 *
                 * Now accessing the new snapshot "snap1" gives problems.
                 * Because the inode and dentry created for snap1 would not be
                 * deleted upon the deletion of the snapshot (as deletion of
                 * snapshot is a gluster cli operation, not a fop). So next time
                 * upon creation of a new snap with same name, the previous
                 * inode and dentry itself will be used. But the inode context
                 * contains old information about the glfs_t instance and the
                 * handle in the gfapi world. Thus the glfs_t instance should
                 * be checked before accessing. If its wrong, then right
                 * instance should be obtained by doing the lookup.
                 */
                if (inode_ctx->fs && inode_ctx->object) {
                        fs = inode_ctx->fs;
                        object = inode_ctx->object;
                        SVS_CHECK_VALID_SNAPSHOT_HANDLE(fs, this);
                        if (fs) {
                                memcpy (buf, &inode_ctx->buf, sizeof (*buf));
                                if (parent)
                                        svs_iatt_fill (parent->gfid,
                                                       postparent);
                                else
                                        svs_iatt_fill (buf->ia_gfid,
                                                       postparent);
                                op_ret = 0;
                                goto out;
                        } else {
                                inode_ctx->fs = NULL;
                                inode_ctx->object = NULL;
                                ret = svs_get_handle (this, loc, inode_ctx,
                                                      op_errno);
                                if (ret) {
                                        gf_log (this->name, GF_LOG_ERROR,
                                                "failed to get the handle for "
                                                "%s (gfid %s)", loc->path,
                                                uuid_utoa_r (loc->inode->gfid,
                                                             tmp_uuid));
                                        op_ret = -1;
                                        goto out;
                                }
                        }
                }

                /* To send the lookup to gfapi world, both the name of the
                   entry as well as the parent context is needed.
                */
                if (!loc->name || !parent_ctx) {
                        *op_errno = ESTALE;
                        gf_log (this->name, GF_LOG_ERROR, "%s is NULL",
                                loc->name?"parent context":"loc->name");
                        goto out;
                }

                if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE)
                        op_ret = svs_lookup_snapshot (this, loc, buf,
                                                      postparent, parent,
                                                      parent_ctx, op_errno);
                else
                        op_ret = svs_lookup_entry (this, loc, buf, postparent,
                                                   parent, parent_ctx,
                                                   op_errno);

                goto out;
        }

out:
        return op_ret;
}

int32_t
svs_lookup (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
        struct iatt    buf                            = {0, };
        int32_t        op_ret                         = -1;
        int32_t        op_errno                       = EINVAL;
        struct iatt    postparent                     = {0,};
        svs_inode_t   *inode_ctx                      = NULL;
        svs_inode_t   *parent_ctx                     = NULL;
        int32_t        ret                            = -1;
        svs_private_t *private                        = NULL;
        inode_t       *parent                         = NULL;
        glfs_t        *fs                             = NULL;
        snap_dirent_t *dirent                         = NULL;
        gf_boolean_t   entry_point                    = _gf_false;

        GF_VALIDATE_OR_GOTO ("svs", this, out);
        GF_VALIDATE_OR_GOTO (this->name, this->private, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        private = this->private;

        /* For lookups sent on inodes (i.e not parent inode + basename, but
           direct inode itself which usually is a nameless lookup or revalidate
           on the inode), loc->name will not be there. Get it from path if
           it is there.
           This is the difference between nameless lookup and revalidate lookup
           on an inode:
           nameless lookup: loc->path contains gfid and strrchr on it fails
           revalidate lookup: loc->path contains the entry name of the inode
                              and strrchr gives the name of the entry from path
        */
        if (loc->path) {
                if (!loc->name || (loc->name && !strcmp (loc->name, ""))) {
                        loc->name = strrchr (loc->path, '/');
                        if (loc->name)
                                loc->name++;
                }
        }

        if (loc->name && strlen (loc->name)) {
                ret = dict_get_str_boolean (xdata, "entry-point", _gf_false);
                if (ret == -1) {
                        gf_log (this->name, GF_LOG_DEBUG, "failed to get the "
                                "entry point info");
                        entry_point = _gf_false;
                } else {
                        entry_point = ret;
                }
        }

        if (loc->parent)
                parent = inode_ref (loc->parent);
        else {
                parent = inode_find (loc->inode->table, loc->pargfid);
                if (!parent)
                        parent = inode_parent (loc->inode, NULL, NULL);
        }
        if (parent)
                parent_ctx = svs_inode_ctx_get (this, parent);

        inode_ctx = svs_inode_ctx_get (this, loc->inode);

        /* Initialize latest snapshot, which is used for nameless lookups */
        dirent = svs_get_latest_snap_entry (this);

        if (dirent && !dirent->fs) {
                fs = svs_initialise_snapshot_volume (this, dirent->name);
        }

        /* lookup is on the entry point to the snapshot world */
        if (entry_point) {
                op_ret = svs_lookup_entry_point (this, loc, parent, &buf,
                                                 &postparent, &op_errno);
                goto out;
        }

        /* revalidate */
        if (inode_ctx) {
                op_ret = svs_revalidate (this, loc, parent, inode_ctx,
                                         parent_ctx, &buf, &postparent,
                                         &op_errno);
                goto out;
        }

        /* This can happen when entry point directory is entered from non-root
           directory. (ex: if /mnt/glusterfs is the mount point, then entry
           point (say .snaps) is entered from /mnt/glusterfs/dir/.snaps). Also
           it can happen when client sends a nameless lookup on just a gfid and
           the server does not have the inode in the inode table.
        */
        if (!inode_ctx && !parent_ctx) {
                op_ret = svs_lookup_gfid (this, loc, &buf, &postparent,
                                          &op_errno);
                goto out;
        }

        if (parent_ctx) {
                if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE)
                        op_ret = svs_lookup_snapshot (this, loc, &buf,
                                                      &postparent, parent,
                                                      parent_ctx, &op_errno);
                else
                        op_ret = svs_lookup_entry (this, loc, &buf,
                                                   &postparent, parent,
                                                   parent_ctx, &op_errno);
                goto out;
        }

out:
        STACK_UNWIND_STRICT (lookup, frame, op_ret, op_errno,
                             loc?loc->inode:NULL, &buf, xdata, &postparent);

        if (parent)
                inode_unref (parent);

        return 0;
}

int32_t
svs_opendir (call_frame_t *frame, xlator_t *this, loc_t *loc, fd_t *fd,
             dict_t *xdata)
{
        svs_inode_t   *inode_ctx  = NULL;
        int32_t        op_ret     = -1;
        int32_t        op_errno   = EINVAL;
        svs_fd_t      *svs_fd     = NULL;
        glfs_fd_t     *glfd       = NULL;
        glfs_t        *fs         = NULL;
        glfs_object_t *object     = NULL;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found "
                        "for the inode %s", uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = ESTALE;
                goto out;
        }

        /* Fake success is sent if the opendir is on the entry point directory
           or the inode is SNAP_VIEW_ENTRY_POINT_INODE
        */
        if  (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                op_ret = 0;
                op_errno = 0;
                goto out;
        }
        else {

                SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                                       op_errno, out);

                glfd = glfs_h_opendir (fs, object);
                if (!glfd) {
                        op_ret = -1;
                        op_errno = errno;
                        gf_log (this->name, GF_LOG_ERROR, "opendir on %s "
                                "failed (gfid: %s)", loc->name,
                                uuid_utoa (loc->inode->gfid));
                        goto out;
                }
                svs_fd = svs_fd_ctx_get_or_new (this, fd);
                if (!svs_fd) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to allocate "
                                "fd context %s (gfid: %s)", loc->name,
                                uuid_utoa (fd->inode->gfid));
                        op_ret = -1;
                        op_errno = ENOMEM;
                        glfs_closedir (glfd);
                        goto out;
                }
                svs_fd->fd = glfd;

                op_ret = 0;
                op_errno = 0;
        }

out:
        STACK_UNWIND_STRICT (opendir, frame, op_ret, op_errno, fd, NULL);

        return 0;
}

/*
 * This function adds the xattr keys present in the list (@list) to the dict.
 * But the list contains only the names of the xattrs (and no value, as
 * the gfapi functions for the listxattr operations would return only the
 * names of the xattrs in the buffer provided by the caller, though they had
 * got the values of those xattrs from posix) as described in the man page of
 * listxattr. But before unwinding snapview-server has to put those names
 * back into the dict. But to get the values for those xattrs it has to do the
 * getxattr operation on each xattr which might turn out to be a costly
 * operation. So for each of the xattrs present in the list, a 0 byte value
 * ("") is set into the dict before unwinding. This can be treated as an
 * indicator to other xlators which want to cache the xattrs (as of now,
 * md-cache which caches acl and selinux related xattrs) to not to cache the
 * values of the xattrs present in the dict.
 */
int32_t
svs_add_xattrs_to_dict (xlator_t *this, dict_t *dict, char *list, ssize_t size)
{
        char           keybuffer[4096]  = {0,};
        size_t         remaining_size   = 0;
        int32_t        list_offset      = 0;
        int32_t        ret              = -1;

        GF_VALIDATE_OR_GOTO ("snapview-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, dict, out);
        GF_VALIDATE_OR_GOTO (this->name, list, out);

        remaining_size = size;
        list_offset = 0;
        while (remaining_size > 0) {
                strcpy (keybuffer, list + list_offset);
#ifdef GF_DARWIN_HOST_OS
                /* The protocol expect namespace for now */
                char *newkey = NULL;
                gf_add_prefix (XATTR_USER_PREFIX, keybuffer, &newkey);
                strcpy (keybuffer, newkey);
                GF_FREE (newkey);
#endif
                ret = dict_set_str (dict, keybuffer, "");
                if (ret < 0) {
                        gf_log (this->name, GF_LOG_ERROR, "dict set operation "
                                "for the key %s failed.", keybuffer);
                        goto out;
                }

                remaining_size -= strlen (keybuffer) + 1;
                list_offset += strlen (keybuffer) + 1;
        } /* while (remaining_size > 0) */

        ret = 0;

out:
        return ret;
}

int32_t
svs_getxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, const char *name,
              dict_t *xdata)
{
        svs_inode_t   *inode_ctx        = NULL;
        int32_t        op_ret           = -1;
        int32_t        op_errno         = EINVAL;
        glfs_t        *fs               = NULL;
        glfs_object_t *object           = NULL;
        char          *value            = 0;
        ssize_t        size             = 0;
        dict_t        *dict             = NULL;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", frame, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", loc, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", loc->inode, out);

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found "
                        "for the inode %s", uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = ESTALE;
                goto out;
        }

        /* EINVAL is sent if the getxattr is on entry point directory
           or the inode is SNAP_VIEW_ENTRY_POINT_INODE. Entry point is
           a virtual directory on which setxattr operations are not
           allowed. If getxattr has to be faked as success, then a value
           for the name of the xattr has to be sent which we dont have.
        */
        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }
        else {

                SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                                       op_errno, out);

                dict = dict_new ();
                if (!dict) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to "
                                "allocate dict");
                        op_ret = -1;
                        op_errno = ENOMEM;
                        goto out;
                }

                size = glfs_h_getxattrs (fs, object, name, NULL, 0);
                if (size == -1) {
                        gf_log (this->name, GF_LOG_ERROR, "getxattr "
                                "on %s failed (key: %s)", loc->name,
                                name);
                        op_ret = -1;
                        op_errno = errno;
                        goto out;
                }
                value = GF_CALLOC (size + 1, sizeof (char),
                                   gf_common_mt_char);
                if (!value) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to "
                                "allocate memory for getxattr on %s "
                                "(key: %s)", loc->name, name);
                        op_ret = -1;
                        op_errno = ENOMEM;
                        goto out;
                }

                size = glfs_h_getxattrs (fs, object, name, value, size);
                if (size == -1) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to "
                                "get the xattr %s for entry %s", name,
                                loc->name);
                        op_ret = -1;
                        op_errno = errno;
                        goto out;
                }
                value[size] = '\0';

                if (name) {
                        op_ret = dict_set_dynptr (dict, (char *)name, value,
                                                  size);
                        if (op_ret < 0) {
                                op_errno = -op_ret;
                                gf_log (this->name, GF_LOG_ERROR, "dict set "
                                        "operation for %s for the key %s "
                                        "failed.", loc->path, name);
                                GF_FREE (value);
                                value = NULL;
                                goto out;
                        }
                } else {
                        op_ret = svs_add_xattrs_to_dict (this, dict, value,
                                                         size);
                        if (op_ret == -1) {
                                gf_log (this->name, GF_LOG_ERROR, "failed to "
                                        "add the xattrs from the list to dict");
                                op_errno = ENOMEM;
                                goto out;
                        }
                        GF_FREE (value);
                }
        }

out:
        if (op_ret)
                GF_FREE (value);

        STACK_UNWIND_STRICT (getxattr, frame, op_ret, op_errno, dict, NULL);

        if (dict)
                dict_unref (dict);

        return 0;
}

int32_t
svs_fgetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, const char *name,
               dict_t *xdata)
{
        svs_inode_t *inode_ctx  = NULL;
        int32_t      op_ret     = -1;
        int32_t      op_errno   = EINVAL;
        char        *value      = 0;
        ssize_t      size       = 0;
        dict_t      *dict       = NULL;
        svs_fd_t    *sfd        = NULL;
        glfs_fd_t   *glfd       = NULL;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", frame, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", fd, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", fd->inode, out);

        inode_ctx = svs_inode_ctx_get (this, fd->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found "
                        "for the inode %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = ESTALE;
                goto out;
        }

        sfd = svs_fd_ctx_get_or_new (this, fd);
        if (!sfd) {
                gf_log (this->name, GF_LOG_ERROR, "failed to get the fd "
                        "context for %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = EBADFD;
                goto out;
        }

        glfd = sfd->fd;
        /* EINVAL is sent if the getxattr is on entry point directory
           or the inode is SNAP_VIEW_ENTRY_POINT_INODE. Entry point is
           a virtual directory on which setxattr operations are not
           allowed. If getxattr has to be faked as success, then a value
           for the name of the xattr has to be sent which we dont have.
        */
        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }
        else {
                dict = dict_new ();
                if (!dict) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to "
                                "allocate  dict");
                        op_ret = -1;
                        op_errno = ENOMEM;
                        goto out;
                }

                if (name) {
                        size = glfs_fgetxattr (glfd, name, NULL, 0);
                        if (size == -1) {
                                gf_log (this->name, GF_LOG_ERROR, "getxattr on "
                                        "%s failed (key: %s)",
                                        uuid_utoa (fd->inode->gfid), name);
                                op_ret = -1;
                                op_errno = errno;
                                goto out;
                        }
                        value = GF_CALLOC (size + 1, sizeof (char),
                                           gf_common_mt_char);
                        if (!value) {
                                gf_log (this->name, GF_LOG_ERROR, "failed to "
                                        "allocate memory for getxattr on %s "
                                        "(key: %s)",
                                        uuid_utoa (fd->inode->gfid), name);
                                op_ret = -1;
                                op_errno = ENOMEM;
                                goto out;
                        }

                        size = glfs_fgetxattr (glfd, name, value, size);
                        if (size == -1) {
                                gf_log (this->name, GF_LOG_ERROR, "failed to "
                                        "get the xattr %s for inode %s", name,
                                        uuid_utoa (fd->inode->gfid));
                                op_ret = -1;
                                op_errno = errno;
                                goto out;
                        }
                        value[size] = '\0';

                        op_ret = dict_set_dynptr (dict, (char *)name, value,
                                                  size);
                        if (op_ret < 0) {
                                op_errno = -op_ret;
                                gf_log (this->name, GF_LOG_ERROR, "dict set "
                                        "operation for gfid %s for the key %s "
                                        "failed.",
                                        uuid_utoa (fd->inode->gfid), name);
                                GF_FREE (value);
                                goto out;
                        }
                } else {
                        size = glfs_flistxattr (glfd, NULL, 0);
                        if (size == -1) {
                                gf_log (this->name, GF_LOG_ERROR, "listxattr "
                                        "on %s failed",
                                        uuid_utoa (fd->inode->gfid));
                                goto out;
                        }

                        value = GF_CALLOC (size + 1, sizeof (char),
                                           gf_common_mt_char);
                        if (!value) {
                                op_ret = -1;
                                op_errno = ENOMEM;
                                gf_log (this->name, GF_LOG_ERROR, "failed to "
                                        "allocate buffer for xattr list (%s)",
                                        uuid_utoa (fd->inode->gfid));
                                goto out;
                        }

                        size = glfs_flistxattr (glfd, value, size);
                        if (size == -1) {
                                op_ret = -1;
                                op_errno = errno;
                                gf_log (this->name, GF_LOG_ERROR, "listxattr "
                                        "on %s failed",
                                        uuid_utoa (fd->inode->gfid));
                                goto out;
                        }

                        op_ret = svs_add_xattrs_to_dict (this, dict, value,
                                                         size);
                        if (op_ret == -1) {
                                gf_log (this->name, GF_LOG_ERROR, "failed to "
                                        "add the xattrs from the list to dict");
                                op_errno = ENOMEM;
                                goto out;
                        }
                        GF_FREE (value);
                }

                op_ret = 0;
                op_errno = 0;
        }

out:
        if (op_ret)
                GF_FREE (value);

        STACK_UNWIND_STRICT (fgetxattr, frame, op_ret, op_errno, dict, NULL);

        if (dict)
                dict_unref (dict);

        return 0;
}

int32_t
svs_releasedir (xlator_t *this, fd_t *fd)
{
        svs_fd_t *sfd      = NULL;
        uint64_t          tmp_pfd  = 0;
        int               ret      = 0;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);

        ret = fd_ctx_del (fd, this, &tmp_pfd);
        if (ret < 0) {
                gf_log (this->name, GF_LOG_DEBUG,
                        "pfd from fd=%p is NULL", fd);
                goto out;
        }

        sfd = (svs_fd_t *)(long)tmp_pfd;
        if (sfd->fd) {
                ret = glfs_closedir (sfd->fd);
                if (ret)
                        gf_log (this->name, GF_LOG_WARNING, "failed to close "
                                "the glfd for directory %s",
                                uuid_utoa (fd->inode->gfid));
        }

out:
        return 0;
}

int32_t
svs_flush (call_frame_t *frame, xlator_t *this,
           fd_t *fd, dict_t *xdata)
{
        int32_t           op_ret   = -1;
        int32_t           op_errno = 0;
        int               ret      = -1;
        uint64_t          value    = 0;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);

        ret = fd_ctx_get (fd, this, &value);
        if (ret < 0) {
                op_errno = EINVAL;
                gf_log (this->name, GF_LOG_WARNING,
                        "pfd is NULL on fd=%p", fd);
                goto out;
        }

        op_ret = 0;

out:
        STACK_UNWIND_STRICT (flush, frame, op_ret, op_errno, NULL);

        return 0;
}

int32_t
svs_release (xlator_t *this, fd_t *fd)
{
        svs_fd_t *sfd      = NULL;
        uint64_t          tmp_pfd  = 0;
        int               ret      = 0;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);

        ret = fd_ctx_del (fd, this, &tmp_pfd);
        if (ret < 0) {
                gf_log (this->name, GF_LOG_DEBUG,
                        "pfd from fd=%p is NULL", fd);
                goto out;
        }

        sfd = (svs_fd_t *)(long)tmp_pfd;
        if (sfd->fd) {
                ret = glfs_close (sfd->fd);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to close "
                                "the glfd for %s",
                                uuid_utoa (fd->inode->gfid));
                }
        }

out:
        return 0;
}

int32_t
svs_forget  (xlator_t *this, inode_t *inode)
{
        int       ret = -1;
        uint64_t  value = 0;
        svs_inode_t  *inode_ctx = NULL;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, inode, out);

        ret = inode_ctx_del (inode, this, &value);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "failed to delte the inode "
                        "context of %s", uuid_utoa (inode->gfid));
                goto out;
        }

        inode_ctx = (svs_inode_t *)value;

        if (inode_ctx->object)
                glfs_h_close (inode_ctx->object);

        GF_FREE (inode_ctx);

out:
        return 0;
}

int
svs_fill_readdir (xlator_t *this, gf_dirent_t *entries, size_t size, off_t off)
{
        gf_dirent_t             *entry          = NULL;
        svs_private_t           *priv           = NULL;
        int                     i               = 0;
        snap_dirent_t           *dirents        = NULL;
        int                     this_size       = 0;
        int                     filled_size     = 0;
        int                     count           = 0;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO ("snap-view-daemon", entries, out);

        priv = this->private;
        GF_ASSERT (priv);

        /* create the dir entries */
        LOCK (&priv->snaplist_lock);
        {
                dirents = priv->dirents;

                for (i = off; i < priv->num_snaps; ) {
                        this_size = sizeof (gf_dirent_t) +
                                strlen (dirents[i].name) + 1;
                        if (this_size + filled_size > size )
                                goto unlock;

                        entry = gf_dirent_for_name (dirents[i].name);
                        if (!entry) {
                                gf_log (this->name, GF_LOG_ERROR,
                                        "failed to allocate dentry for %s",
                                        dirents[i].name);
                                goto unlock;
                        }

                        entry->d_off = i + 1;
                        /*
                         * readdir on the entry-point directory to the snapshot
                         * world, will return elements in the list of the
                         * snapshots as the directory entries. Since the entries
                         * returned are virtual entries which does not exist
                         * physically on the disk, pseudo inode numbers are
                         * generated.
                         */
                        entry->d_ino = i + 2*42;
                        entry->d_type = DT_DIR;
                        list_add_tail (&entry->list, &entries->list);
                        ++i;
                        count++;
                        filled_size += this_size;
                }
        }
unlock:
        UNLOCK (&priv->snaplist_lock);

out:
        return count;
}

int32_t
svs_glfs_readdir (xlator_t *this, glfs_fd_t *glfd, gf_dirent_t *entries,
                  int32_t *op_errno, struct iatt *buf, gf_boolean_t readdirplus,
                  size_t size)
{
        int              filled_size    = 0;
        int              this_size      = 0;
        int32_t          ret            = -1;
        int32_t          count          = 0;
        gf_dirent_t     *entry          = NULL;
        struct   dirent *dirents        = NULL;
        struct   dirent  de             = {0, };
        struct stat      statbuf        = {0, };
        off_t            in_case        = -1;

        GF_VALIDATE_OR_GOTO ("svs", this, out);
        GF_VALIDATE_OR_GOTO (this->name, glfd, out);
        GF_VALIDATE_OR_GOTO (this->name, entries, out);
        GF_VALIDATE_OR_GOTO (this->name, buf, out);

        while (filled_size < size) {
                in_case = glfs_telldir (glfd);
                if (in_case == -1) {
                        gf_log (this->name, GF_LOG_ERROR, "telldir failed");
                        break;
                }

                if (readdirplus)
                        ret = glfs_readdirplus_r (glfd, &statbuf, &de,
                                                  &dirents);
                else
                        ret = glfs_readdir_r (glfd, &de, &dirents);

                if (ret == 0 && dirents != NULL) {
                        if (readdirplus)
                                this_size = max (sizeof (gf_dirent_t),
                                                 sizeof (gfs3_dirplist))
                                        + strlen (de.d_name) + 1;
                        else
                                this_size = sizeof (gf_dirent_t)
                                        + strlen (de.d_name) + 1;

                        if (this_size + filled_size > size) {
                                glfs_seekdir (glfd, in_case);
                                break;
                        }

                        entry = gf_dirent_for_name (de.d_name);
                        if (!entry) {
                                gf_log (this->name, GF_LOG_ERROR,
                                        "could not create gf_dirent "
                                        "for entry %s: (%s)",
                                        entry->d_name,
                                        strerror (errno));
                                break;
                        }
                        entry->d_off = glfs_telldir (glfd);
                        entry->d_ino = de.d_ino;
                        entry->d_type = de.d_type;
                        iatt_from_stat (buf, &statbuf);
                        if (readdirplus)
                                entry->d_stat = *buf;
                        list_add_tail (&entry->list, &entries->list);

                        filled_size += this_size;
                        count++;
                } else if (ret == 0 && dirents == NULL) {
                        *op_errno = ENOENT;
                        break;
                } else if (ret != 0) {
                        *op_errno = errno;
                        break;
                }
                dirents = NULL;
                ret = -1;
        }

out:
        return count;
}

/* readdirp can be of 2 types.
   1) It can come on entry point directory where the list of snapshots
      is sent as dirents. In this case, the iatt structure is filled
      on the fly if the inode is not found for the entry or the inode
      context is NULL. Other wise if inode is found and inode context
      is there the iatt structure saved in the context is used.
   2) It can be on a directory in one of the snapshots. In this case,
      the readdirp call would have sent us a iatt structure. So the same
      structure is used with the exception that the gfid and the inode
      numbers will be newly generated and filled in.
*/
void
svs_readdirp_fill (xlator_t *this, inode_t *parent, svs_inode_t *parent_ctx,
                   gf_dirent_t *entry)
{
        inode_t                *inode          = NULL;
        uuid_t                  random_gfid    = {0,};
        struct  iatt            buf            = {0, };
        svs_inode_t            *inode_ctx      = NULL;

        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
        GF_VALIDATE_OR_GOTO (this->name, parent, out);
        GF_VALIDATE_OR_GOTO (this->name, parent_ctx, out);
        GF_VALIDATE_OR_GOTO (this->name, entry, out);

        inode = inode_grep (parent->table, parent, entry->d_name);
        if (inode) {
                entry->inode = inode;
                inode_ctx = svs_inode_ctx_get (this, inode);
                if (!inode_ctx) {
                        uuid_copy (buf.ia_gfid, inode->gfid);
                        svs_iatt_fill (inode->gfid, &buf);
                        buf.ia_type = inode->ia_type;
                } else {
                        buf = inode_ctx->buf;
                }

                entry->d_ino = buf.ia_ino;

                if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE)
                        entry->d_stat = buf;
                else {
                        entry->d_stat.ia_ino = buf.ia_ino;
                        uuid_copy (entry->d_stat.ia_gfid, buf.ia_gfid);
                }
        } else {
                inode = inode_new (parent->table);
                entry->inode = inode;
                uuid_generate (random_gfid);
                uuid_copy (buf.ia_gfid, random_gfid);
                svs_fill_ino_from_gfid (&buf);
                entry->d_ino = buf.ia_ino;

                /* If inode context allocation fails, then do not send the
                   inode for that particular entry as part of readdirp
                   response. Fuse and protocol/server will link the inodes
                   in readdirp only if the entry contains inode in it.
                */
                inode_ctx = svs_inode_ctx_get_or_new (this, inode);
                if (!inode_ctx) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to allocate "
                                "inode context for %s", entry->d_name);
                        inode_unref (entry->inode);
                        entry->inode = NULL;
                        goto out;
                }


                if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                        buf.ia_type = IA_IFDIR;
                        inode_ctx->buf = buf;
                        entry->d_stat = buf;
                        inode_ctx->type = SNAP_VIEW_SNAPSHOT_INODE;
                } else {
                        uuid_copy (entry->d_stat.ia_gfid, buf.ia_gfid);
                        entry->d_stat.ia_ino = buf.ia_ino;
                        inode_ctx->buf = entry->d_stat;
                        inode_ctx->type = SNAP_VIEW_VIRTUAL_INODE;
                }
        }

out:
        return;
}

/* In readdirp, though new inode is created along with the generation of
   new gfid, the inode context created will not contain the glfs_t instance
   for the filesystem it belongs to and the handle for it in the gfapi
   world. (handle is obtained only by doing the lookup call on the entry
   and doing lookup on each entry received as part of readdir call is a
   costly operation. So the fs and handle is NULL in the inode context
   and is filled in when lookup comes on that object.
*/
int32_t
svs_readdirp (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
              off_t off, dict_t *dict)
{
        gf_dirent_t             entries;
        gf_dirent_t            *entry                           = NULL;
        struct  iatt            buf                             = {0, };
        int                     count                           = 0;
        int                     op_ret                          = -1;
        int                     op_errno                        = EINVAL;
        svs_inode_t            *parent_ctx                      = NULL;
        svs_fd_t               *svs_fd                          = NULL;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, unwind);
        GF_VALIDATE_OR_GOTO (this->name, frame, unwind);
        GF_VALIDATE_OR_GOTO (this->name, fd, unwind);
        GF_VALIDATE_OR_GOTO (this->name, fd->inode, unwind);

        INIT_LIST_HEAD (&entries.list);

        parent_ctx = svs_inode_ctx_get (this, fd->inode);
        if (!parent_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "failed to get the inode "
                        "context for %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto unwind;
        }

        if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                LOCK (&fd->lock);
                {
                        count = svs_fill_readdir (this, &entries, size, off);
                }
                UNLOCK (&fd->lock);

                op_ret = count;

                list_for_each_entry (entry, &entries.list, list) {
                        svs_readdirp_fill (this, fd->inode, parent_ctx, entry);
                }

                goto unwind;
        } else {
                svs_fd = svs_fd_ctx_get_or_new (this, fd);
                if (!svs_fd) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to get the "
                                "fd context %s", uuid_utoa (fd->inode->gfid));
                        op_ret = -1;
                        op_errno = EBADFD;
                        goto unwind;
                }

                glfs_seekdir (svs_fd->fd, off);

                LOCK (&fd->lock);
                {
                        count = svs_glfs_readdir (this, svs_fd->fd, &entries,
                                                  &op_errno, &buf, _gf_true,
                                                  size);
                }
                UNLOCK (&fd->lock);

                op_ret = count;

                list_for_each_entry (entry, &entries.list, list) {
                        svs_readdirp_fill (this, fd->inode, parent_ctx, entry);
                }

                goto unwind;
        }

unwind:
        STACK_UNWIND_STRICT (readdirp, frame, op_ret, op_errno, &entries, dict);

        gf_dirent_free (&entries);

        return 0;
}

int32_t
svs_readdir (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
             off_t off, dict_t *xdata)
{
        svs_private_t *priv      = NULL;
        gf_dirent_t    entries   = {{{0, }, }, };
        int            count     = 0;
        svs_inode_t   *inode_ctx = NULL;
        int            op_errno  = EINVAL;
        int            op_ret    = -1;
        svs_fd_t      *svs_fd    = NULL;
        glfs_fd_t     *glfd      = NULL;

        INIT_LIST_HEAD (&entries.list);

        GF_VALIDATE_OR_GOTO ("snap-view-server", this, unwind);
        GF_VALIDATE_OR_GOTO (this->name, frame, unwind);
        GF_VALIDATE_OR_GOTO (this->name, fd, unwind);
        GF_VALIDATE_OR_GOTO (this->name, fd->inode, unwind);

        priv = this->private;

        inode_ctx = svs_inode_ctx_get (this, fd->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found in "
                        "the inode %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto unwind;
        }

        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                LOCK (&fd->lock);
                {
                        count = svs_fill_readdir (this, &entries, size, off);
                }
                UNLOCK (&fd->lock);
        } else {
                svs_fd = svs_fd_ctx_get_or_new (this, fd);
                if (!svs_fd) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to get the "
                                "fd context %s", uuid_utoa (fd->inode->gfid));
                        op_ret = -1;
                        op_errno = EBADFD;
                        goto unwind;
                }

                glfd = svs_fd->fd;

                LOCK (&fd->lock);
                {
                        count = svs_glfs_readdir (this, glfd, &entries,
                                                  &op_errno, NULL, _gf_false,
                                                  size);
                }
                UNLOCK (&fd->lock);
        }

        op_ret = count;

unwind:
        STACK_UNWIND_STRICT (readdir, frame, op_ret, op_errno, &entries, xdata);

        gf_dirent_free (&entries);

        return 0;
}

/*
 * This function is mainly helpful for NFS. Till now NFS server was not linking
 * the inodes in readdirp, which caused problems when below operations were
 * performed.
 *
 * 1) ls -l in one of the snaopshots (snapview-server would generate gfids for
 *    each entry on the fly and link the inodes associated with those entries)
 * 2) NFS server upon getting readdirp reply would not link the inodes of the
 *    entries. But it used to generate filehandles for each entry and associate
 *    the gfid of that entry with the filehandle and send it as part of the
 *    reply to nfs client.
 * 3) NFS client would send the filehandle of one of those entries when some
 *    activity is done on it.
 * 4) NFS server would not be able to find the inode for the gfid present in the
 *    filehandle (as the inode was not linked) and would go for hard resolution
 *    by sending a lookup on the gfid by creating a new inode.
 * 5) snapview-client will not able to identify whether the inode is a real
 *    inode existing in the main volume or a virtual inode existing in the
 *    snapshots as there would not be any inode context.
 * 6) Since the gfid upon which lookup is sent is a virtual gfid which is not
 *    present in the disk, lookup would fail and the application would get an
 *    error.
 *
 * The above problem is fixed by the below commit which makes snapview server
 * more compatible with nfs server (1dea949cb60c3814c9206df6ba8dddec8d471a94).
 * But now because NFS server does inode linking in readdirp has introduced
 * the below issue.
 * In readdirp though snapview-server allocates inode contexts it does not
 * actually perform lookup on each entry it obtained in readdirp (as doing
 * a lookup via gfapi over the network for each entry would be costly).
 *
 * Till now it was not a problem with NFS server, as NFS was sending a lookup on
 * the gfid it got from NFS client, for which it was not able to find the right
 * inode. So snapview-server was able to get the fs instance (glfs_t) of the
 * snapshot volume to which the entry belongs to, and the handle for the entry
 * from the corresponding snapshot volume and fill those informations in the
 * inode context.
 *
 * But now, since NFS server is able to find the inode from the inode table for
 * the gfid it got from the NFS client, it wont send lookup. Rather it directly
 * sends the fop it received from the client. Now this causes problems for
 * snapview-server. Because for each fop snapview-server assumes that lookup has
 * been performed on that entry and the entry's inode context contains the
 * pointers for the fs instance and the handle to the entry in that fs. When NFS
 * server sends the fop and snapview-server finds that the fs instance and the
 * handle within the inode context are NULL it unwinds with EINVAL.
 *
 * So to handle this, if fs instance or handle within the inode context are
 * NULL, then do a lookup based on parent inode context's fs instance. And
 * unwind the results obtained as part of lookup
 */

int32_t
svs_get_handle (xlator_t *this, loc_t *loc, svs_inode_t *inode_ctx,
                int32_t *op_errno)
{
        svs_inode_t   *parent_ctx   = NULL;
        int            ret          = -1;
        inode_t       *parent       = NULL;
        struct iatt    postparent   = {0, };
        struct iatt    buf          = {0, };
        char           uuid1[64];

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        if (loc->path) {
                if (!loc->name || (loc->name && !strcmp (loc->name, ""))) {
                        loc->name = strrchr (loc->path, '/');
                        if (loc->name)
                                loc->name++;
                }
        }

        if (loc->parent)
                parent = inode_ref (loc->parent);
        else {
                parent = inode_find (loc->inode->table, loc->pargfid);
                if (!parent)
                        parent = inode_parent (loc->inode, NULL, NULL);
        }

        if (parent)
                parent_ctx = svs_inode_ctx_get (this, parent);

        if (!parent_ctx) {
                gf_log (this->name, GF_LOG_WARNING, "failed to get the parent "
                        "context for %s (%s)", loc->path,
                        uuid_utoa_r (loc->inode->gfid, uuid1));
                *op_errno = EINVAL;
                goto out;
        }

        if (parent_ctx) {
                if (parent_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE)
                        ret = svs_lookup_snapshot (this, loc, &buf,
                                                   &postparent, parent,
                                                   parent_ctx, op_errno);
                else
                        ret = svs_lookup_entry (this, loc, &buf,
                                                &postparent, parent,
                                                parent_ctx, op_errno);
        }

out:
        if (parent)
                inode_unref (parent);

        return ret;
}

int32_t
svs_stat (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
        svs_private_t *priv         = NULL;
        struct iatt    buf          = {0, };
        int32_t        op_errno     = EINVAL;
        int32_t        op_ret       = -1;
        svs_inode_t   *inode_ctx    = NULL;
        glfs_t        *fs           = NULL;
        glfs_object_t *object       = NULL;
        struct stat    stat         = {0, };
        int            ret          = -1;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        priv = this->private;

        /* Instead of doing the check of whether it is a entry point directory
           or not by checking the name of the entry and then deciding what
           to do, just check the inode context and decide what to be done.
        */

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found for"
                        " %s", uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }

        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                svs_iatt_fill (loc->inode->gfid, &buf);
                op_ret = 0;
        }
        else {

                SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                                       op_errno, out);

                ret = glfs_h_stat (fs, object, &stat);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR, "glfs_h_stat on %s "
                                "(gfid: %s) failed", loc->name,
                                uuid_utoa (loc->inode->gfid));
                        op_ret = -1;
                        op_errno = errno;
                        goto out;
                }

                iatt_from_stat (&buf, &stat);
                uuid_copy (buf.ia_gfid, loc->inode->gfid);
                svs_fill_ino_from_gfid (&buf);
                op_ret = ret;
        }

out:
        STACK_UNWIND_STRICT (stat, frame, op_ret, op_errno, &buf, xdata);
        return 0;
}

int32_t
svs_fstat (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *xdata)
{
        svs_private_t *priv        = NULL;
        struct iatt    buf         = {0, };
        int32_t        op_errno    = EINVAL;
        int32_t        op_ret      = -1;
        svs_inode_t   *inode_ctx   = NULL;
        struct stat    stat        = {0, };
        int            ret         = -1;
        glfs_fd_t     *glfd        = NULL;
        svs_fd_t      *sfd         = NULL;

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);
        GF_VALIDATE_OR_GOTO (this->name, fd->inode, out);

        priv = this->private;

        /* Instead of doing the check of whether it is a entry point directory
           or not by checking the name of the entry and then deciding what
           to do, just check the inode context and decide what to be done.
        */

        inode_ctx = svs_inode_ctx_get (this, fd->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found for"
                        " the inode %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }

        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                svs_iatt_fill (fd->inode->gfid, &buf);
                op_ret = 0;
        }
        else {
                sfd = svs_fd_ctx_get_or_new (this, fd);
                if (!sfd) {
                        gf_log (this->name, GF_LOG_ERROR, "failed to get the "
                                "fd context for %s",
                                uuid_utoa (fd->inode->gfid));
                        op_ret = -1;
                        op_errno = EBADFD;
                        goto out;
                }

                glfd = sfd->fd;
                ret = glfs_fstat (glfd, &stat);
                if (ret) {
                        gf_log (this->name, GF_LOG_ERROR, "glfs_fstat on "
                                "gfid: %s failed", uuid_utoa (fd->inode->gfid));
                        op_ret = -1;
                        op_errno = errno;
                        goto out;
                }

                iatt_from_stat (&buf, &stat);
                uuid_copy (buf.ia_gfid, fd->inode->gfid);
                svs_fill_ino_from_gfid (&buf);
                op_ret = ret;
        }

out:
        STACK_UNWIND_STRICT (fstat, frame, op_ret, op_errno, &buf, xdata);
        return 0;
}

int32_t
svs_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
          fd_t *fd, dict_t *xdata)
{
        svs_inode_t   *inode_ctx = NULL;
        svs_fd_t      *sfd       = NULL;
        int32_t        op_ret    = -1;
        int32_t        op_errno  = EINVAL;
        glfs_fd_t     *glfd      = NULL;
        glfs_t        *fs        = NULL;
        glfs_object_t *object    = NULL;


        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context for %s "
                        "(gfid: %s) not found", loc->name,
                        uuid_utoa (loc->inode->gfid));
                goto out;
        }

        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE)
                GF_ASSERT (0); // on entry point it should always be opendir

        SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                               op_errno, out);

        glfd = glfs_h_open (fs, object, flags);
        if (!glfd) {
                gf_log (this->name, GF_LOG_ERROR, "glfs_h_open on %s failed "
                        "(gfid: %s)", loc->name, uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = errno;
                goto out;
        }

        sfd = svs_fd_ctx_get_or_new (this, fd);
        if (!sfd) {
                gf_log (this->name, GF_LOG_ERROR, "failed to allocate fd "
                        "context for %s (gfid: %s)", loc->name,
                        uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = ENOMEM;
                glfs_close (glfd);
                goto out;
        }
        sfd->fd = glfd;

        op_ret = 0;

out:
        STACK_UNWIND_STRICT (open, frame, op_ret, op_errno, fd, NULL);
        return 0;
}

int32_t
svs_readv (call_frame_t *frame, xlator_t *this,
           fd_t *fd, size_t size, off_t offset, uint32_t flags, dict_t *xdata)
{
        int32_t                op_ret     = -1;
        int32_t                op_errno   = 0;
        svs_private_t         *priv       = NULL;
        struct iobuf          *iobuf      = NULL;
        struct iobref         *iobref     = NULL;
        struct iovec           vec        = {0,};
        svs_fd_t              *sfd        = NULL;
        int                    ret        = -1;
        struct stat            fstatbuf   = {0, };
        glfs_fd_t             *glfd       = NULL;
        struct iatt            stbuf      = {0, };

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, fd, out);
        GF_VALIDATE_OR_GOTO (this->name, fd->inode, out);

        priv = this->private;
        VALIDATE_OR_GOTO (priv, out);

        sfd = svs_fd_ctx_get_or_new (this, fd);
        if (!sfd) {
                gf_log (this->name, GF_LOG_ERROR, "failed to get the fd "
                        "context for %s", uuid_utoa (fd->inode->gfid));
                op_ret = -1;
                op_errno = EBADFD;
                goto out;
        }

        glfd = sfd->fd;

        iobuf = iobuf_get2 (this->ctx->iobuf_pool, size);
        if (!iobuf) {
                op_ret = -1;
                op_errno = ENOMEM;
                goto out;
        }

        ret = glfs_pread (glfd, iobuf->ptr, size, offset, 0);
        if (ret < 0) {
                op_ret = -1;
                op_errno = errno;
                gf_log (this->name, GF_LOG_ERROR, "glfs_read failed (%s)",
                        strerror (op_errno));
                goto out;
        }

        vec.iov_base = iobuf->ptr;
        vec.iov_len  = ret;

        iobref = iobref_new ();

        iobref_add (iobref, iobuf);

        ret = glfs_fstat (glfd, &fstatbuf);
        if (ret) {
                op_ret = -1;
                op_errno = errno;
                gf_log (this->name, GF_LOG_ERROR, "glfs_fstat failed after "
                        "readv on %s", uuid_utoa (fd->inode->gfid));
                goto out;
        }

        iatt_from_stat (&stbuf, &fstatbuf);
        uuid_copy (stbuf.ia_gfid, fd->inode->gfid);
        svs_fill_ino_from_gfid (&stbuf);

        /* Hack to notify higher layers of EOF. */
        if (!stbuf.ia_size || (offset + vec.iov_len) >= stbuf.ia_size)
                op_errno = ENOENT;

        op_ret = vec.iov_len;

out:

        STACK_UNWIND_STRICT (readv, frame, op_ret, op_errno,
                             &vec, 1, &stbuf, iobref, NULL);

        if (iobref)
                iobref_unref (iobref);
        if (iobuf)
                iobuf_unref (iobuf);

        return 0;
}

int32_t
svs_readlink (call_frame_t *frame, xlator_t *this,
              loc_t *loc, size_t size, dict_t *xdata)
{
        svs_inode_t     *inode_ctx = NULL;
        glfs_t          *fs        = NULL;
        glfs_object_t   *object    = NULL;
        int              op_ret    = -1;
        int              op_errno  = EINVAL;
        char            *buf       = NULL;
        struct iatt      stbuf     = {0, };
        int              ret       = -1;
        struct stat      stat      = {0, };

        GF_VALIDATE_OR_GOTO ("snap-view-daemon", this, out);
        GF_VALIDATE_OR_GOTO (this->name, frame, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "failed to get inode context "
                        "for %s (gfid: %s)", loc->name,
                        uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }

        SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                               op_errno, out);

        ret = glfs_h_stat (fs, object, &stat);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR, "glfs_h_stat on %s "
                        "(gfid: %s) failed", loc->name,
                        uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = errno;
                goto out;
        }

        iatt_from_stat (&stbuf, &stat);
        uuid_copy (stbuf.ia_gfid, loc->inode->gfid);
        svs_fill_ino_from_gfid (&stbuf);

        buf = alloca (size + 1);
        op_ret = glfs_h_readlink (fs, object, buf, size);
        if (op_ret == -1) {
                gf_log (this->name, GF_LOG_ERROR, "readlink on %s failed "
                        "(gfid: %s)", loc->name, uuid_utoa (loc->inode->gfid));
                op_errno = errno;
                goto out;
        }

        buf[op_ret] = 0;

out:
        STACK_UNWIND_STRICT (readlink, frame, op_ret, op_errno, buf, &stbuf,
                             NULL);

        return 0;
}

int32_t
svs_access (call_frame_t *frame, xlator_t *this, loc_t *loc, int mask,
            dict_t *xdata)
{
        int             ret          = -1;
        int32_t         op_ret       = -1;
        int32_t         op_errno     = EINVAL;
        svs_private_t  *priv         = NULL;
        glfs_t         *fs           = NULL;
        glfs_object_t  *object       = NULL;
        svs_inode_t    *inode_ctx    = NULL;
        gf_boolean_t    is_fuse_call = 0;
        int             mode         = 0;

        GF_VALIDATE_OR_GOTO ("svs", this, out);
        GF_VALIDATE_OR_GOTO (this->name, this->private, out);
        GF_VALIDATE_OR_GOTO (this->name, loc, out);
        GF_VALIDATE_OR_GOTO (this->name, loc->inode, out);

        priv = this->private;

        inode_ctx = svs_inode_ctx_get (this, loc->inode);
        if (!inode_ctx) {
                gf_log (this->name, GF_LOG_ERROR, "inode context not found for"
                        " %s", uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = EINVAL;
                goto out;
        }

        is_fuse_call = __is_fuse_call (frame);

        /*
         * For entry-point directory, set read and execute bits. But not write
         * permissions.
         */
        if (inode_ctx->type == SNAP_VIEW_ENTRY_POINT_INODE) {
                if (is_fuse_call) {
                        op_ret = 0;
                        op_errno = 0;
                } else {
                        op_ret = 0;
                        mode |= POSIX_ACL_READ;
                        mode |= POSIX_ACL_EXECUTE;
                        op_errno = mode;
                }
                goto out;
        }


        SVS_GET_INODE_CTX_INFO(inode_ctx, fs, object, this, loc, op_ret,
                               op_errno, out);

        /* The actual posix_acl xlator does acl checks differently for
           fuse and nfs. So set frame->root->pid as fspid of the syncop
           if the call came from nfs
        */
        if (!is_fuse_call)
                syncopctx_setfspid (&frame->root->pid);

        ret = glfs_h_access (fs, object, mask);
        if (ret < 0) {
                gf_log (this->name, GF_LOG_ERROR, "failed to access %s "
                        "(gfid: %s)", loc->path, uuid_utoa (loc->inode->gfid));
                op_ret = -1;
                op_errno = errno;
                goto out;
        }

        op_ret = 0;
        op_errno = ret;

out:

        STACK_UNWIND_STRICT (access, frame, op_ret, op_errno, NULL);
        return 0;
}


int32_t
mem_acct_init (xlator_t *this)
{
        int     ret = -1;

        if (!this)
                return ret;

        ret = xlator_mem_acct_init (this, gf_svs_mt_end + 1);

        if (ret != 0) {
                gf_log (this->name, GF_LOG_WARNING, "Memory accounting"
                        " init failed");
                return ret;
        }

        return ret;
}

int32_t
init (xlator_t *this)
{
        svs_private_t   *priv           = NULL;
        int             ret             = -1;
        pthread_t       snap_thread;

        /* This can be the top of graph in certain cases */
        if (!this->parents) {
                gf_log (this->name, GF_LOG_DEBUG,
                        "dangling volume. check volfile ");
        }

        priv = GF_CALLOC (1, sizeof (*priv), gf_svs_mt_priv_t);
        if (!priv)
                goto out;

        this->private = priv;

        GF_OPTION_INIT ("volname", priv->volname, str, out);
        LOCK_INIT (&priv->snaplist_lock);

        LOCK (&priv->snaplist_lock);
        {
                priv->num_snaps = 0;
        }
        UNLOCK (&priv->snaplist_lock);

        /* What to do here upon failure? should init be failed or succeed? */
        /* If succeeded, then dynamic management of snapshots will not */
        /* happen.*/
        ret = svs_mgmt_init (this);
        if (ret) {
                gf_log (this->name, GF_LOG_WARNING, "failed to initiate the "
                        "mgmt rpc callback for svs. Dymamic management of the"
                        "snapshots will not happen");
                goto out;
        }

        /* get the list of snaps first to return to client xlator */
        ret = svs_get_snapshot_list (this);
        if (ret) {
                gf_log (this->name, GF_LOG_ERROR,
                        "Error initializing snaplist infrastructure");
                ret = -1;
                goto out;
        }

        ret = 0;

out:
        if (ret && priv) {
                LOCK_DESTROY (&priv->snaplist_lock);
                GF_FREE (priv->dirents);
                GF_FREE (priv);
        }

        return ret;
}

void
fini (xlator_t *this)
{
        svs_private_t   *priv   = NULL;
        glusterfs_ctx_t *ctx    = NULL;
        int             ret     = 0;

        GF_ASSERT (this);
        priv = this->private;
        this->private = NULL;
        ctx = this->ctx;
        if (!ctx)
                gf_log (this->name, GF_LOG_ERROR,
                        "Invalid ctx found");

        if (priv) {
                ret = LOCK_DESTROY (&priv->snaplist_lock);
                if (ret != 0) {
                        gf_log (this->name, GF_LOG_WARNING,
                                "Could not destroy mutex snaplist_lock");
                }

                if (priv->dirents) {
                        GF_FREE (priv->dirents);
                }

                if (priv->rpc) {
                        /* cleanup the saved-frames before last unref */
                        rpc_clnt_connection_cleanup (&priv->rpc->conn);
                        rpc_clnt_unref (priv->rpc);
                }

                GF_FREE (priv);
        }

        return;
}

struct xlator_fops fops = {
        .lookup     = svs_lookup,
        .stat       = svs_stat,
        .opendir    = svs_opendir,
        .readdirp   = svs_readdirp,
        .readdir    = svs_readdir,
        .open       = svs_open,
        .readv      = svs_readv,
        .flush      = svs_flush,
        .fstat      = svs_fstat,
        .getxattr   = svs_getxattr,
        .access     = svs_access,
        /* entry fops */
};

struct xlator_cbks cbks = {
        .release  = svs_release,
        .releasedir = svs_releasedir,
        .forget     = svs_forget,
};

struct volume_options options[] = {
        { .key  = {"volname"},
          .type = GF_OPTION_TYPE_STR,
        },
        { .key  = {NULL} },
};