[LU-36] mdd_la_get is called too many times in MDD

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.6.0, Lustre 2.5.1
• Affects Version/s: Lustre 2.0.0
• Assignee: Lai Siyao
• Reporter: Liang Zhen (Inactive)

Description

I created this ticket for several reasons:

• we called mdd_la_get for so many times in MDD, it's not good for performance of high contention pdir operations.
• mdd_attr_check is not strictly correct under pdir operations, there is still chance to decrease ctime because we don't have exclusive lock on parent while checking ctime
• mdd_attr_check_set_internal and mdd_attr_check_set_internal_locked can be merged into one function: mdd_cmtime_check_set_internal, because set cmtime is the only use-case of them.