[LU-5767] LFSCK 3: replace LFSCK RPC with normal OUT RPC to create orphan parent on remote MDT

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.7.0
• Affects Version/s: Lustre 2.7.0
• Labels: HB
• Severity: 3
• Assignee: nasf (Inactive)
• Reporter: nasf (Inactive)

Description

When the namespace LFSCK tries to repair the missing name entry, means inserting the lost name entry back to its parent directory, it may find that the parent MDT-object is also lost. Under such case, the namespace LFSCK will firstly create the missing parent MDT-object as an orphan and insert into the .lustre/lost+found/MDTxxxx/ directory with the name:

${FID}-P-${conflict_version}.

Then insert the lost name entry into the orphan parent according to the MDT-object's linkEA.

Currently, the namespace LFSCK uses LFSCK RPC to handle the case of creating orphan parent MDT-object on remote MDT. It is not the normal way for cross-MDTs modification that usually will be handled via OUT RPC. Please refer to the comment on gerrit for more discussion:

http://review.whamcloud.com/#/c/11391/28/lustre/lfsck/lfsck_namespace.c,cm