[LU-6361] LFSCK 4: improve LFSCK performance - Whamcloud Community JIRA

It is used for tracing all LFSCK 4 tasks.

Progress

1.	LFSCK 4: Improve inode iteration for uninitialized groups	Resolved	nasf (Inactive)
2.	LFSCK 4: Improve OI scrub trigger strategy: do not trigger urgent OI scrub on the whole system if only few inconsistent OI entries are found	Resolved	nasf (Inactive)
3.	LFSCK 4: Record linkEA verification history in RAM	Resolved	nasf (Inactive)
4.	LFSCK 4: optimize ldlm lock used by LFSCK	Resolved	nasf (Inactive)
5.	LFSCK 4: namespace LFSCK can skip dot entry	Resolved	nasf (Inactive)
6.	LFSCK 4: namespace LFSCK counts the objects repeatedly	Resolved	nasf (Inactive)
7.	LFSCK 4: locate object only when necessary	Resolved	nasf (Inactive)
8.	LFSCK 4: lock the MDT-object based on prediction for preparing bad linkEA	Resolved	nasf (Inactive)
9.	LFSCK 4: show LFSCK started/completed time directly via LFSCK lproc interface	Resolved	nasf (Inactive)
10.	LFSCK 4: namespace LFSCK scalability	Resolved	nasf (Inactive)
11.	LFSCK MDS crash: unable to handle kernel NULL pointer dereference	Resolved	nasf (Inactive)