mkfs.ext4dev unrecognised file system

[Paul Graydon]

This is probably a bit of a daft one, and it's not blocking me on anything, but I see this more as a UX bug.

mkfs.ext4dev creates a file system that mount then can't mount, unless it is told explicitly that it is ext4.

(on a side note, what is ext4dev? Can't seem to find a solid answer)

$ sudo mkfs.ext4dev /dev/sdb
mke2fs 1.42.13 (17-May-2015)
/dev/sdb contains a ext4 file system
        last mounted on Fri Nov 24 22:40:41 2017
Proceed anyway? (y,n) y
Creating filesystem with 268435456 4k blocks and 67108864 inodes
Filesystem UUID: d5dcc961-f34e-4f59-b0f5-f58ea75dc817
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

$ sudo mount /dev/sdb mount
mount: unknown filesystem type 'ext4dev'

$ sudo mount -t ext4 mount
$
/dev/sdb on /home/ubuntu/mount type ext4 (rw,relatime,data=ordered)

doing a normal mkfs.ext4 works perfectly fine, as you'd expect.

Version: Ubuntu 16.04
Package: e2fsprogs 1.42.13-1ubuntu1