LFSCK always trust FID in LMA more than FID in directory entry and FID in linkea, but it may be corrupt, or it's an IGIF(upgraded from 1.8), while the FID in child's linkea is standard FID. Currently such inconsistency can only be fixed manually, however for special objects like ROOT, it should be able to be repaird automatically. This can be achieved by checking special object LMA during the early mount-time scan, and checking if the subdirectories under ROOT/ have a trusted.link entry matching fid_is_root(), in which case the LMA FID is wrong (probably an IGIF FID) and should be fixed to use [FID_SEQ_ROOT:FID_OID_ROOT:0x0], rather than the IGIF FID.