[systemd-devel] Suppressing automounting

[Tobias Geerinckx-Rice]

Hallo,

On 11 September 2014 19:41, Dale R. Worley <worley at alum.mit.edu> wrote:
> > From: Colin Guthrie <gmane at colin.guthr.ie>
> > I'm maybe missing something, but in the case of mount units, isn't that
> > framework program mount(8)?
> >
> > It has a mechanism for parsing default options that apply to all mounts
> > and then calling out to the appropriate, filesystem specific mount
> > program (e.g. mount.nfs, mount.cifs, mount.crypt, mount.fuse etc. etc.)
> > if appropriate.
>
> mount does the real work, of course, but it isn't the complete
> solution,

Er, "solution" to what, exactly? People here seem (rightly)
unconvinced there's any problem at all.

And yes, calling mount -- by definition -- actually is the "complete
solution" to mounting a file system under Linux.

> because *something* has to figure out not only that
> /bin/mount should be invoked, but what its arguments are.
>
> And as you can see from the unit file
>
[SNIP]
>     What=/dev/Freeze02/Store2
>     Where=/Store
>     Type=ext4
[SNIP]
>     Options=nofail,x-systemd.device-timeout=1m,defaults
>
> none of that is specified *directly* in the unit file.

Now surely, calling

    /usr/bin/mount $What $Where [-t $Type] [-o $Options]

is about as direct as it gets. Being able to substitute the only
constant in that equation with /usr/bin/gimp really isn't going to
solve any problem, real or imagined.

> Some piece of code has to know to assemble the What, Where, Type,
> and Options values (at the very least) -- and that piece of code is what
> contains special knowledge of how to handle mount units.

Again: straightforward use of a standard Unix API that just happens to
be in a separate binary != special knowledge. Really. It's
programming.

Step back, and define exactly what it is you actually need^Wwant to do.

>From my reading of the thread, this is to emulate as closely ye olde
initscripts' unreliable and flawed behaviour of attempting to mount
one or more devices exactly once (i.e., a one-shot "mount -a"), but
not until an arbitrary time-out has elapsed after which all external
devices are blindly assumed to have been initialised for no good
reason.

This isn't hard to achieve with systemd, but there's a good reason I
wrote it in such a silly manner, that can't simply be ignored.

Regards (and good luck nonetheless),

T G-R