added a comment - https://testing.whamcloud.com/test_sets/36d6c354-969b-11e8-87f3-52540065bddc shows this test may fail on ZFS system, but the log shows everything is fine, maybe it's just slower on ZFS because this test triggers a lot of sync, so I add a patch to test with fewer files on ZFS system.
00000100:00100000:0.0:1533234765.487631:0:1111:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_004:2f34b462-f472-4056-b60b-b18d27585747+52:29420:x1607707738583120:12345-10.9.5.233@tcp:36 Request processed in 188518us (188545us total) trans 30064828518 rc 0/0
00000100:00100000:0.0:1533234767.038819:0:1111:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_004:2f34b462-f472-4056-b60b-b18d27585747+51:29425:x1607707738583376:12345-10.9.5.233@tcp:36 Request processed in 342118us (342149us total) trans 30064828525 rc 0/0
00000100:00100000:0.0:1533234780.768498:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+43:29457:x1607707738585616:12345-10.9.5.233@tcp:36 Request processed in 304782us (304807us total) trans 30064828581 rc 0/0
00000100:00100000:0.0:1533234783.263416:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+41:29466:x1607707738586192:12345-10.9.5.233@tcp:36 Request processed in 324538us (324557us total) trans 30064828595 rc 0/0
00000100:00100000:1.0:1533234784.844937:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+40:29470:x1607707738586448:12345-10.9.5.233@tcp:36 Request processed in 330485us (330510us total) trans 30064828602 rc 0/0
00000100:00100000:1.0:1533234785.995696:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+39:29474:x1607707738586704:12345-10.9.5.233@tcp:36 Request processed in 260063us (260092us total) trans 30064828609 rc 0/0
00000100:00100000:1.0:1533234786.611092:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+41:29476:x1607707738586832:12345-10.9.5.233@tcp:36 Request processed in 253504us (253534us total) trans 30064828612 rc 0/0
00000100:00100000:1.0:1533234787.789783:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+38:29481:x1607707738587152:12345-10.9.5.233@tcp:36 Request processed in 544241us (544269us total) trans 30064828619 rc 0/0
00000100:00100000:1.0:1533234789.474735:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+37:29485:x1607707738587408:12345-10.9.5.233@tcp:36 Request processed in 278538us (278567us total) trans 30064828626 rc 0/0
00000100:00100000:1.0:1533234790.474337:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+36:29489:x1607707738587664:12345-10.9.5.233@tcp:36 Request processed in 281511us (281540us total) trans 30064828633 rc 0/0
00000100:00100000:1.0:1533234791.552662:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+35:29493:x1607707738587920:12345-10.9.5.233@tcp:36 Request processed in 236237us (236258us total) trans 30064828640 rc 0/0
00000100:00100000:0.0:1533234792.903815:0:27386:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_002:2f34b462-f472-4056-b60b-b18d27585747+33:29499:x1607707738588368:12345-10.9.5.233@tcp:36 Request processed in 212071us (212102us total) trans 30064828651 rc 0/0
00000100:00100000:1.0:1533234793.704464:0:29335:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_003:2f34b462-f472-4056-b60b-b18d27585747+32:29503:x1607707738588624:12345-10.9.5.233@tcp:36 Request processed in 255002us (255020us total) trans 30064828658 rc 0/0
00000100:00100000:0.0:1533234795.052945:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+31:29507:x1607707738588880:12345-10.9.5.233@tcp:36 Request processed in 330962us (330981us total) trans 30064828665 rc 0/0
00000100:00100000:1.0:1533234795.933959:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+30:29511:x1607707738589136:12345-10.9.5.233@tcp:36 Request processed in 281057us (281076us total) trans 30064828672 rc 0/0
00000100:00100000:0.0:1533234799.414898:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+29:29515:x1607707738589456:12345-10.9.5.233@tcp:36 Request processed in 1534920us (1534949us total) trans 30064828679 rc 0/0
00000100:00100000:1.0:1533234799.814291:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+31:29517:x1607707738589584:12345-10.9.5.233@tcp:36 Request processed in 242121us (242147us total) trans 30064828683 rc 0/0
00000100:00100000:1.0:1533234800.933214:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+28:29521:x1607707738589840:12345-10.9.5.233@tcp:36 Request processed in 275937us (275980us total) trans 30064828689 rc 0/0
00000100:00100000:1.0:1533234802.446459:0:13204:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_005:2f34b462-f472-4056-b60b-b18d27585747+27:29525:x1607707738590096:12345-10.9.5.233@tcp:36 Request processed in 675885us (675913us total) trans 30064828696 rc 0/0
00000100:00100000:0.0:1533234803.561883:0:29335:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_003:2f34b462-f472-4056-b60b-b18d27585747+26:29529:x1607707738590416:12345-10.9.5.233@tcp:36 Request processed in 182042us (182076us total) trans 30064828703 rc 0/0
00000100:00100000:0.0:1533234805.587818:0:21305:0:(service.c:2179:ptlrpc_server_handle_request()) Handled RPC pname:cluuid+ref:pid:xid:nid:opc mdt00_009:2f34b462-f472-4056-b60b-b18d27585747+25:29533:x1607707738590672:12345-10.9.5.233@tcp:36 Request processed in 240344us (240363us total) trans 30064828710 rc 0/0
00000080:00200000:1.0:1533234793.012979:0:29503:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.483, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.483, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234793.595477:0:29505:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.484, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.484, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234794.285507:0:29507:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.485, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.485, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234794.717644:0:29509:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.486, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.486, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234795.216400:0:29511:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.487, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.487, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234795.786463:0:29513:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.488, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.488, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234797.443481:0:29515:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.489, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.489, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234799.135678:0:29517:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.490, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.490, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234799.604788:0:29519:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.491, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.491, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234800.220776:0:29521:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.492, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.492, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234800.721058:0:29523:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.493, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.493, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234801.334046:0:29525:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.494, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.494, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234802.226146:0:29527:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.495, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.495, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234802.943331:0:29529:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.496, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.496, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234803.710463:0:29531:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.497, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.497, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:0.0:1533234804.911002:0:29533:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.498, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.498, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234805.698636:0:29535:0:(namei.c:1585:ll_rename()) VFS Op:oldname=f415.sanity.499, src_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90), newname=f415.sanity-new.499, tgt_dir=[0x2c00013a6:0xc:0x0](ffff9ce7d429ad90)
00000080:00200000:1.0:1533234792.933728:0:29502:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234793.268569:0:29504:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234794.029610:0:29506:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234794.617157:0:29508:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234794.956394:0:29510:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234795.498048:0:29512:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234795.994119:0:29514:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234798.979155:0:29516:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234799.379232:0:29518:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234799.703506:0:29520:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234800.497299:0:29522:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234800.942789:0:29524:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234802.010655:0:29526:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234802.362924:0:29528:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234803.126157:0:29530:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234804.268186:0:29532:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234805.151920:0:29534:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:0.0:1533234805.854663:0:29536:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
00000080:00200000:1.0:1533234806.508497:0:29538:0:(llite_lib.c:1589:ll_setattr_raw()) lustre: setattr inode [0x2c00013a6:0xc:0x0](ffff9ce7d429ad90) from 11264 to 131290, valid 20070, hsm_import 0
https://testing.whamcloud.com/test_sets/36d6c354-969b-11e8-87f3-52540065bddc shows this test may fail on ZFS system, but the log shows everything is fine, maybe it's just slower on ZFS because this test triggers a lot of sync, so I add a patch to test with fewer files on ZFS system.