[LU-1750] Update next_id even the previous process already clear the orphans

• Type: Bug
• Resolution: Won't Fix
• Priority: Blocker
• Affects Version/s: Lustre 2.4.0
• Severity: 3
• Assignee: Di Wang
• Reporter: Di Wang

Description

During orphan cleanup, OST should always update last_id, even though the previous threads might already cleanup orphans. Considering following case

1. mds start, send clear orphan req to OST, and OST begin to clear orphan, but then MDS fails before it gets reply. i.e. it does not update next_id yet.
2. mds restart and send clear orphan req again to OST with original next_id, then it found the orphan has been cleanup, so still reply with the original id, which is wrong, and we should update next_id in this case.