If directory migration fails in the middle, the system may become inconsistent, and some files may get missing. LFSCK should use the informations in directory layout to restore system to consistent mode.

This will be done in two phases, in the first phase, LFSCK against such directories won't resolve all the inconsistencies, but it shouldn't cause additional issues, and after LFSCK the directories should be accessed, though some file may get lost, while in the second phase, LFSCK should use the informations in directory layout to restore system to consistent mode, and should avoid file missing.