Re: "Operation not supported" using EncFS over WebDAV gvfs-mount

[Adam Tauno Williams <awilliam whitemice org>]

On Wed, 2016-05-11 at 14:54 +0200, R. Diez wrote:
> > Unfortunately GIO is not POSIX-compatible and thus some operations
> > are
> > not possible over FUSE, see following commit message:
> > https://git.gnome.org/browse/gvfs/commit/?id=548ba46c2ba51c4ec5b0dd
> > 8442b476f3a2a7000b
> First of all, thanks for your help.
> Given that comment, I think stating that "GIO is not POSIX
> -compatible" is a vast understatement. Lots of software will just not 
> work properly.
> Did I miss some obvious warning about that? I would argue that, if 
> GIO mounts something over FUSE, most people would expect it to work 
> well in normal scenarios. If some weird permission issue arises, no 
> one would be surprised, but if such basic functionality is missing, 
> that would be a surprise, right?

And it does work normally in most situations.  I work on documents over
WebDAV via GVFS all the time.  In the case of WebDAV it can also depend
on the backend server - which may or may not permit some operations.

> If I need to use gvfs-copy instead of cp to be sure, then I do not 
> need to mount anything over FUSE!

"cp" should work.

> I actually want to mount an encrypted filesystem like EncFS over a 
> gvfs-mount WebDAV mount, but from your answer, it seems that this is 
> not possible. If this is a GIO limitation, I take it that it wouldn't
> work either for any other mounting protocols like SMB or SSH, would 
> it? 

It depends on a lot of details.  I would expect it to work - but it
does depend on how EncFS does this.  Debugging what GVFS is doing is
not that hard.

In a terminal window I run -
  ulimit -c unlimited
  killall -15 /usr/lib/gvfs/gvfsd \
    /usr/lib/gvfs/gvfs-udisks2-volume-monitor \
    /usr/lib/gvfs/gvfs-afc-volume-monitor \
    /usr/lib/gvfs/gvfs-gphoto2-volume-monitor \
    /usr/lib/gvfs/gvfsd-trash \
    /usr/lib/gvfs/gvfsd-burn \
    /usr/lib/gvfs/gvfsd-metadata \
    /usr/lib/gvfs/gvfsd-http \
    /usr/lib/gvfs/gvfsd-dav
  GVFS_DEBUG=1 GVFS_HTTP_DEBUG=all /usr/lib/gvfs/gvfsd -r

- which whacks all the GVFS services and restarts them in the terminal
window.  Then you can see, or log, the output.

On the other hand, IMO, GVFS stability/compatibility has declined
somewhat in recent iterations.


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