Re: [fuse-devel] PATCH: Unmount on inactivity (2)

[Miklos S. <mi...@sz...>]

> > Sorry, I'm a bit late in the discussion, and it's not perfectly clear
> > to me how this feature would be used.  Is it part of an automount
> > feature?
> 
> Yes, it's one of the applications. I have two uses for it:
> 
>  - I am currently using autofs to automount NFS shares from a server,
> and I have trouble with permissions, because my user is in more than 15
> groups (this is an NFS-specific limitation). So I wanted to replace NFS
> by sshfs. I found the afuse filesystem, based on fuse, that provides
> automount capability. But it unfortunately lacks automatic unmount on
> inactivity.
> 
>  - encfs already provides this feature, to unmount an encrypted
> filesystem if it isn't used (for security purposes). This avoids having
> to remember unmounting it e.g. before leaving my laptop.

This makes some sense, although the security aspect is not entirely
satisfied, since open files or CWD within the mount will defeat
unmounting.

> Even if I don't use afuse for automounting (due to its overhead), and
> instead mount my server using sshfs by hand, I'd like it to unmount
> automatically if the mount is idle for a few minutes.

For sshfs, a better solution would be to disconnect from the server,
but not actually unmount.  And reconnect on new activity.  The
reconnect part is already working, and adding forced disconnection
does not seem too hard.

This would have the advantage, that CWD within the mountpoint wouldn't
defeat disconnection.  Open files would still defeat it, reopening
files after a reconnect would be a nice (but a bit complex) feature.

> I could have extended afuse to implement the unmount-on-idle feature,
> but I figured it might be an interesting feature for other filesystems
> based on fuse, and I was able to implement it a bit more elegantly in
> the library itself.

Right.  What I recommend, is that we wait a bit with adding this to
the library, to see if people find it useful, and possibly until a
stacking infrastructure is added to libfuse.

Thanks,
Miklos