unexpected softupdate inconsistency

[Gregory Bond]

msergeant at snsonline.net said:
> In situations like this it can be useful to use vim on the dir entry
> that is affected and remove the invalid filenames. This has worked for
> me before.

I'm astounded.  

Directories are not supposed to be modifiable by user-space processes at all,
only with link/unlink/creat/etc system calls, because the risk of filesystem
corruption is huge.  What does vim do here that rm doesn't? And how does it get
around the "cant write(2) directories" ban?

See man open:

     [EISDIR]           The named file is a directory, and the arguments spec-
                        ify it is to be opened for writing.