[LU-20093] lnet: restore local NI status when clearing fatal link state

• Type: Bug
• Resolution: Fixed
• Priority: Medium
• Fix Version/s: Lustre 2.18.0
• Severity: 3
• Assignee: Serguei Smirnov
• Reporter: Serguei Smirnov

Description

lnetctl net show reports local NI status via ni->ni_status unless the fatal bit is set. When a link-down event marks a local NI "down", clearing
ni_fatal_error_on on link recovery does not necessarily restore the
cached NI status to UP.

This can leave a local NI reported as DOWN.

Restore the exported NI status to "UP" when clearing the fatal link state
for a fully healthy NI, and push the update to peers if the status
changed.