prevent inappropriate unmount of remote storage

<http://groups.google.com/group/MacFusion-devel/msg/d7fe4cdf6ac3c6aa>

> There is no reason why EncFS cant be stacked on top of another Fuse
> file-system or network storage. Ive tested it with FTPFS and it
> works fine for that.
> 
> Just be careful not to unmount the storage volume before EncFS or it
> will lock up and needs to be forcibly unmounted ( The system remains
> responsive ). 

## Request for enhancement

If we have a MacFusion daemon 
(MacFusion issue 163) then maybe future versions of MacFusion could be
aware of dependencies such as the one described by Corsec. 

## Extension of the logic

The example here is EncFS stacked on FTPFS. I guess that a similar
logic should be applied to other stacking situations -- not limited to
existing plug-ins to MacFusion. 

## Implementation

I don't know how to prevent (or at least warn against) unmount of a
remote volume that is being used in this way.

We already know that Finder uses data within a
._ dot underscore file to signfify business of the file's 
   counterpart (during Finder copy operations). 

So, if we wish to signify busi-ness of a remote directory that is
being used for EncFS storage ...

1) My first thought (as someone with no real knowledge of code) was
that MacFusion or EncFS might periodically (frequently) write a very
small amount of data (probably to include the string brokMACS) to

    ._directorybusy

at the root of the directory that is used for storage by EncFS -- for
as long as MacFusion is aware that the user has used MacFusion to
mount an EncFS volume.

I note the presence of the .encfs5 control file, I assume that this is
reserved for other purposes.

2) Frequent attempts to write to a remote volume will be undesirable
after sleeping then waking the computer, so whatever mechanism is used
should be sensitive to availabillity/responsiveness (at the MacFUSE
level?) of the remote file system.

Just guesses. I imagine that a write to the EncFS storage by anything
_other_ than EncFS is, as a rule of thumb, A Very Bad Thing.

At <http://code.google.com/p/macfusion/wiki/SeeAlso> we have a link to
SleepWatcher. Maybe SleepWatcher, or something like it, could serve a
useful purpose here.
Original issue reported on code.google.com by grahampe...@gmail.com on 27 May 2007 at 10:46
michaelogrant / macfusion

prevent inappropriate unmount of remote storage #164
