Emacs c-X c-W doesn't increment the "number of writes to file" fdb halfword

[Gail Zacharias <GZ%MIT-OZ@MIT-MC.ARPA>]

    Date: Wednesday, 21 November 1984  06:26-EST
    From: Leigh L. Klotz <KLOTZ at MIT-MC>
    There are screws involved in doing it the other way -- something about if
    the system crashes.

The screw (aside from the possibility of leaving a partially written file)
is that on tnx, opening a file for write wipes out the old contents of the file
first, and starts writing the new contents second, so if the system crashes
you could lose both.

Is the problem that the reference counts get copied from the old file or
just that they don't get updated?  If the latter, emacs could reopen the
file for append after the rename, just to touch it.