[LU-8283] start_statahead_thread() must decrement ll_sa_running on error

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.9.0
• Labels: statahead
• Severity: 3
• Assignee: WC Triage
• Reporter: John Hammond

Description

Seen on 2.8.54 after running racer. Somehow memory was tight and kthread_run() failed from start_statahead_thread():

LustreError: 26489:0:(statahead.c:1580:start_statahead_thread()) can't start ll_sa thread, rc: -12

After this umount hangs in ll_kill_super() waiting for sbi->ll_sa_running to drop to zero.