[systemd-devel] [ANNOUNCE] systemd 219

[Lennart Poettering]

On Tue, 17.02.15 23:30, Colin Guthrie (gmane at colin.guthr.ie) wrote:

> Lennart Poettering wrote on 17/02/15 10:08:
> >> > mount something-else /foo
> >> > systemctl start foo.mount
> > In this case the second line is a NOP, since the first line already
> > mounted something on /foo, and thus made foo.mount active.
> 
> So, even if foo.mount (the actual unit file) specifies it's
> What=something (not What=something-else) the fact that *anything* is
> mounted to /foo is sufficient to make the foo.mount unit active?

Yes, and this always has been that way.

> This seems somewhat counter-intuitive to me. I can understand why from
> an implementation perspective - the mount units are all geared around
> the mountpoint not the What=, but it's certainly not what I'd expect as
> a user.

Well it's the only logic that can work really, already since the same
device node is usually known to the kernel by a different name thatn
to userspace. Trying to always map that is really nasty, as one can
see with the GPT generator complexity.

> Wouldn't it be better if there was some other state - e.g. "conflict" if
> something other than the desired device was mounted to the specified
> destination?

I think it's really safe not to consider that a problem.

Lennart

-- 
Lennart Poettering, Red Hat