[LU-14183] broken ldlm_add_waiting_lock usage

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Vitaly Fertman
• Reporter: Vitaly Fertman

Description

exp_bl_lock_at accounted the period since BLAST send until cancel RPC came to server originally. LU-6032 started to update l_blast_sent for expired locks which are still busy - prolonged locks when the timeout expired. In fact, this is a good idea to cover not the whole period but until any involved RPC comes - it avoids excessively large lock callback timeouts - and the IO which does the lock prolong is also able to re-start the AT cycle by updating the l_blast_sent.

Unfortunately, the change seems to be made occasionally as the main prolong code was not adjusted accordingly.