[this is getting pretty sick--should I only respond to tech-kern?]


>>
>> >it seems to be that the name undelete is ok.  would you
>> >have both a file available for undeletion, and a whiteout
>> >in existence at the same time?
>>
>> You could have successive undelete(2) calls.  First one zaps the
>> whiteout, the second restores the file.
>
>I'm not really knowledgable on this, but wouldn't the removal of
>the whiteout imply the restoration of the file?  I was under the

No, because the whiteout'd file can subsequently be unlinked(2) see
below.

>impression that removing a file from the underlying readonly FS
>was what causes the creation of the whiteout?  Wouldn't it follow
>that the undelete call does the reverse?
>If I'm way off, ignore me.. :-)

Lower layer is NFS, upper UFS.
Whiteout the file on the client.
Remove the file on the server.

You will be in the situation described in the first paragraph of this
message.