>> I don't understand the notion of using xattr for control.  They are
>> extra properties stored on files, and it seems semantically abusive to
>> write them as a control operation.   (Having .codactl is also a bit
>> abusive, but it's s single clean break.)
>
> Not all are appropriate but from a quick scan the following would fit
> very nicely with the concept of properties on files and/or volumes:
>
>     cfs setacl/listacl  other filesystems also use xattrs for these
>     cfs getfid          get the fid
>     cfs whereis         get the replica server names/addresses
>     cfs listvol         get the volume information
>     cfs getmountpoint   get the nearest ancestor volume mount?
>     cfs lsmount         read the contents of the covered mountlink
>     cfs listlocal       show volume CML

For things that are properties of files that are made consistent by
coda, this seems ok, modulo implementation concerns.  But it
appropriates the namespace from the user for other things.  Also, backup
programs will (should) back up xattr by default, so that may be an
issue.