[sshfs] (FreeBSD) why can't I mount GBDE on top of sshfs ?

[Ensel S. <us...@dh...>]

Hi,

I have posted this before onsome FreeBSD mailing lists and gotten no
response - perhaps the problem with mounting a file-based FS on top of
sshfs has more to do with FUSE ?

Basically, I have remote storage that I can access over ssh (from
rsync.net, who I _love_) and I use sshfs in FreeBSD 6.0 ports tree to
mount my filesystem locally.  I followed this FreeBSD sshfs tutorial:

http://www.rsync.net/resources/howto/freebsd_sshfs.html

The good news is, it works great.  The bad news is, I cannot create a GBDE
in the mounted sshfs.  Here are the details:

I use this HOWTO to do a GEOM based disk encryption (encrypted FS backed
by a file):  
http://0x06.sigabrt.de/howtos/freebsd_encrypted_image_howto.html

When I place the backing-store-file (for my GBDE) on a mounted sshfs
(fuse) volume, it no longer works.  Specifically, when I issue command:

gbde init /dev/md0 -i -L /etc/gbde/md0

and save the resulting file that opens in my editor (without making any
changes, as usual), after typing in my passphrase twice, I get this error:

Enter new passphrase:
Reenter new passphrase: 
gbde: write: Input/output error
#


Is this expected ?  Is this a specific problem with fuse-fs, or would this
fail if I tried to put the backing store on any kind of other mounted
abnormal filesystem ? (say an NFS mount, or another md-backed mount point)

Any comments ?  I really want an offsite encrypted volume.  I have the
offsite from rsync.net, and the transport is encrypted via sshfs, but I am
paranoid and do not want them (or anyone) to see the contants, so I want
to just upload a single 2gig file and make a GBDE on it.

thanks.