The largedir feature was intended to allow ext4 directories to have
unmapped directory blocks (e.g., directory holes).  And so the
released e2fsprogs no longer enforces this for largedir file systems;
however, the corresponding change to the kernel-side code was not made.

This commit fixes this oversight.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org