[systemd-devel] Again, why this strange behavior implied by "auto" in fstab ?

[Lennart Poettering]

On Di, 23.01.18 16:54, Reindl Harald (h.reindl at thelounge.net) wrote:

> 
> 
> Am 23.01.2018 um 16:49 schrieb Simon McVittie:
> > On Tue, 23 Jan 2018 at 15:47:21 +0100, Franck Bui wrote:
> > > Basically, systemd mounts all filesystems listed in /etc/fstab (unless
> > > "noauto" is used) which is good since that's how fstab was used when
> > > SysV was the init system.
> > > 
> > > However it also introduced another "feature" which basically
> > > automagically mounts a filesystem (listed in fstab) every time its
> > > backend device re-appears.
> > 
> > Am I right in thinking this is only done if the filesystem is not declared
> > as noauto in fstab?
> 
> with Fedora 27 (yesterday upgraded) systemd even don't leave "noauto"
> mount-point in peace and spits the "Failed to read symlink target for
> /mnt/arrakis: Permission denied" for fuse-mountpoints multiple times each
> day into the systemlogs (systemd-234-9.fc27.x86_64)

Yeah, FUSE is weird. It exposes mount points that root can't
access. I am note sure how we could safely detect such mounts in a
non-ugly way though (as statvfs() on such mounts won't work), and I am
not sure we should downgrade EACCES log messages in a blanket fashion
since usually they indicate MAC issues, that shouldn't be ignored...

We do generate mount units for all mount points listed in /etc/fstab
unconditionally. This is so that RequiresMountsFor= can work for them
and such. Specifying "noauto" doesn't mean "don't generate mount units
at all". It just means "don't pull them explicitly into the initial
transaction".

Anyway, please file a github issue, we should do something about this.

(That said, this is entirely unrelated to Franck's point AFAICS)

Lennart

-- 
Lennart Poettering, Red Hat