```
b Batch mode. Optimized for huge recursive copies, but less secure if a crash happens during the copy.
```
It seems the "less secure if a crash happens" does not need a crash to
happen.
With batch mode:
```
/[...]/.
Start (0) does not point to parent (___)
```
For pretty much everything copied in.
Without batch mode, everything passes `fsck`.
See #51150
1b6a4d3979