make_ext4fs to generate filesystem

Interesting. I didn't know about this feature in the 6th edition Unix's mkfs. It's not something which the BSD Fast File System supported, and my involvement with Unix started with BSD 4.3.

Using a proto file so that the system can more easily create device files does make sense, and of course these days we need to have something which supports SELinux attributes as well. That's one of the reasons why contrib/e2fsdroid exists. (The other is that e2fsdroid uses the Android libsparse file to create an image which omits the all zero blocks and which is compatible with the existing Android image creation tools, and I didn't want to drag that into mke2fs as a shared library dependency, since that would make distro installer release engineers.... cranky.)

Patches to support some kind of proto file which supports SELinux attributes, and which uses the qemu image file creation functions in libext2fs for mke2fs would certainly be gratefully accepted. If we had that, plus the per-block dedup functionality to create shared blocks file system added, then yes, we could upstream all of that functionality into mke2fs, and allow other embedded systems developers access to e2fsdroid functionality without having to build AOSP....