A little question about safe mode
Andriy Gapon
avg at FreeBSD.org
Thu Oct 18 10:34:34 UTC 2012
on 18/10/2012 12:11 Alexander Yerenkow said the following:
>
>
> 2012/10/18 Andriy Gapon <avg at freebsd.org <mailto:avg at freebsd.org>>
>
>
> First, I see "safe mode" mentioned in the subject, but nowhere in the body of
> the message? So, what's up with the safe mode? :-)
>
>
> The single mode of course, which is forced :) Mistype, sorry.
>
>
> on 18/10/2012 10:35 Alexander Yerenkow said the following:
> > Hello there.
> > I have problem here, and don't know if it's bug or "feature" :)
> > If I prerare boot media (hdd, sd card,usb, etc) with FreeBSD, and NOT
> > create there fstab, I see such behavior:
> >
> > 1. I need enter manually where from mount root (e.g. ufs:ada0s1a or
> > ufs:ada0s1a rw)
>
> This is a feature.
> You might want consider using options ROOTDEVNAME in your kernel.
>
>
> Okay, then why little help there mentioning "rw" as an option? It's of bug in
> help there, or in parsing mount options (rw is ignored).
Again, it's a feature, "rw" is simply ignored.
The help message is just trying to confuse you.
> If I'm not fully clear - I can provide some screenshots.
>
>
>
> > 2. If I enter ufs:ada0s1a rw - I have / mounted in read-only anyway. <== Is
> > this bug?...
>
> It looks like a feature. The low-level mountroot code always mounts / as r/o.
>
> It's supposed to be later remounted as r/w by rc.d/root script.
>
>
> Yes, it's feature when it mounting with default parameters (e.g. with none). But
> what about rw?
This should be answered above.
> > 3. If I try to make it rw, with commands
> > mount -o rw -u /dev/ada0s1a /
> > there is no errors, but root is still RO.
>
> This sounds like a bug.
> Is there anything on the system console?
>
>
> Nope, I'm already on console in single mode.
>
>
> > 4. I can't umount / remount some elsewhere this disk, just to create fstab
> > (it's already mounted and can't be updated).
> >
> > So, is this as-by-design, that you need "any other" media to boot, just to
> > create fstab, or there is "rw" mode broken, or I just missed something?
> >
> > It's very disappointing to be able boot interactively into system, but have
> > no way to "fix" fstab to make it non-interactively bootable :)
>
> You can try to create an md-based filesystem, mount it under /mnt and then
> unionfs-mount it over /etc.
>
>
> That's not solve problem that on my rootfs no fstab exists, so next boot will
> bring me to same situation.
You may try to edit /etc/fstab on top of unionfs and then see if you can remount
the real root r/w.
> If someone willing to help/debug with this thing - get any bootable media (like
> live FreeBSD), and just rename/move/delete fstab file, and simply boot.
There indeed appears to be a bug. Unfortunately, ENOTIME to dig into this.
--
Andriy Gapon
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