[LU-15935] MDT mount fails with "duplicate generation for client export" during failover

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.16.0, Lustre 2.15.3
• Affects Version/s: Lustre 2.14.0, Lustre 2.12.8, Lustre 2.12.9
• Severity: 3
• Assignee: Etienne Aujames
• Reporter: Andreas Dilger

Description

Mounting the MDT during recovery immediately fails with:

(tgt_lastrcvd.c:1575:tgt_clients_data_init()) fs2-MDT000f: duplicate export for client generation 17
(obd_config.c:559:class_setup()) setup fs2-MDT000f failed (-114)
(obd_config.c:1836:class_config_llog_handler()) MGC10.11.12.142@o2ib: cfg command failed: rc = -114
Lustre:    cmd=cf003 0:fs2-MDT000f  1:fs2-MDT000f_UUID  2:15  3:fs2-MDT000f-mdtlov  4:f  
15c-8: MGC10.11.12.142@o2ib: The configuration from log 'fs2-MDT000f' failed (-114).
    This may be the result of communication errors between this node and the MGS, a bad
    configuration, or other errors. See the syslog for more information.
obd_mount_server.c:1408:server_start_targets()) failed to start server fs2-MDT000f: -114
obd_mount_server.c:2052:server_fill_super()) Unable to start targets: -114

There appear to be duplicate client recovery records in the MDT's last_rcvd file that are preventing it from creating all of the client exports in tgt_clients_data_init(). It doesn't have anything to do with the MGS, despite the later messages. Removing the last_rcvd file allowed the MDT to be mounted, as likely mounting with "-o abort_recov" would have done.

Issue Links

• is duplicated by: LU-7794 tgt_clients_data_init()) soaked-MDT0001: duplicate export for client generation 1
• is related to: LU-6468 Interop 2.5.3<->master conf-sanity test_83: No space left on device