[LU-959] kuc channels not reestablished after MDS crash

• Type: Bug
• Resolution: Cannot Reproduce
• Priority: Minor
• Affects Version/s: Lustre 2.0.0, Lustre 2.1.0
• Severity: 3
• Assignee: Niu Yawei (Inactive)
• Reporter: Thomas LEIBOVICI - CEA (Inactive)

Description

It seams the kuc channels are not reestablished after a MDS crash.
In particular, process that are listening for changelogs remain stuck listening to the kernel->userspace pipe
whereas no message is sent from the MDS, as clients do not re-register kuc listeners after reconnecting to the MDS.

It would probably need an action in mdc_import_event() to reregister kuc listeners,
something like:

in mdc_import_event():

case IMP_EVENT_ACTIVE: {
rc = obd_notify_observer(obd, obd, OBD_NOTIFY_ACTIVE, NULL);
+ /* restore re-establish kuc registration after reconnecting */
+ if (rc == 0)
+ rc = mdc_kuc_reregister(imp);