My guess is that given the history of this filesystem implementation, most of the review effort will be focused on the interface between this FS and the rest of the kernel. It's typical for all the changes touching communal files or introducing generic helper functions or data structures to be broken out into separate commits. If any of those helpers are a reinvention of stuff that's already in the kernel, there will need to be a justification for why NTFS needs its own special versions. It's not typical for a large patch series adding genuinely new stuff to be broken up into absurdly tiny commits. For the stuff that's truly internal to the filesystem implementation, it looks like one patch per file will be an acceptable granularity.