ubuntu-users Digest, Vol 102, Issue 18

[Tom H]

On Tue, Feb 5, 2013 at 6:26 PM, Adam Wolfe <kadamwolfe at gmail.com> wrote:
> On Tue, Feb 5, 2013 at 10:56 AM, Adam Wolfe <kadamwolfe at gmail.com> wrote:


>>> Why were all the grub entries made to mount / as read-only?
>>> Why do most of these options attempt a fsck (and seem to fail) before
>>> doing anything else?
>>
>> The "ro" on the "linux" lines of the stanzas don't mean that "/" is
>> mounted read-only once the system's fully booted up.
>>
>> The grub "linux" lines have "ro" to allow "/" to be mounted read-only
>> and fsck'd. It's then remounted read-write. So it's unsurprising that
>> fsck's failing.
>
> I'm really sorry folks, I meant to say all of the "recovery" grub options.
> The normal boot options, and my custom ones for clonezilla and gparted isos
> are just fine. It's the recovery options that mount everything ro and/or
> try to fsck for no reason. This all happened after a do-release-upgrade
> from 10.04 to 12.04.

This is on 12.10 so it *may* be the same as 12.04, or not...

I've always assumed that booting into single-user mode gave you a
read-only "/"... I've rebooted a Gentoo VM with "S" appended and
that's indeed the case. I don't have any other distribution that I can
reboot at the moment to compare.

I've just rebooted my 12.10 laptop with "S" appended and I ended up at
a read-write "/".

I was expecting the Ubuntu recovery menu because it's a new install
and I havent't disabled it yet so I checked 10_linux and the
"(recovery mode)" stanzas are now adding "recovery" rather than
"single" (!). it must be an Ubuntu-specific option because I've never
seen it before and it boots into the Ubuntu friendly-recovery menu. If
you choose the "root shell" option, you get a root prompt and "/"
mounted read-only.

I assuem from your email that the "root shell" option used to give you
a read-write "/" on 10.04. Check the sulogin (from the sysvinit-utils
package) and friendly-recovery changelogs.


>>> Why does it not boot the default selection on reboot after having chosen
>>> recovery at the previous boot?
>>
>> What's "GRUB_DEFAULT" set to in "/etc/default/grub"?
>
> Oddly, it's "GRUB_DEFAULT=0". That was the first thing I went for as well.
> After choosing a recovery mode, doing whatever, then rebooting, it gets to
> the grub menu and sits. Like it's ignoring the GRUB_DEFAULT and
> GRUB_TIMEOUT values. But it's only after booting to a recovery mode.
> Choosing any other entry from grub, even the custom ones, then rebooting
> again, it will then boot the set default entry.
> Here's my full /etc/default/grub:
> name at changeme:~$ grep -v \# /etc/default/grub
> GRUB_DEFAULT=0
> GRUB_HIDDEN_TIMEOUT=0
> GRUB_HIDDEN_TIMEOUT_QUIET=true
> GRUB_TIMEOUT=3
> GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
> GRUB_CMDLINE_LINUX_DEFAULT="quiet"
> GRUB_CMDLINE_LINUX=""

It sounds like "recordfail" is coming into play.

What does "grub-editenv list" return when you're booted into recovery mode?


> I've been able to over-write (albeit perhaps only until the next upgrade of
> grub) the read-only issue by editing /etc/grub.d/10_linux. But as for the
> other two issues... really annoying. Has anyone found an easy way around
> this? Installing grub from source, maybe? Or is there a simple "on/off"
> switch.
>
> If you really want to edit 10_linux (for a reason other than changing
> "ro" to "rw"!), I'd advise you to do the following:
>
> cp 10_linux 11_linux
> mv 10_linux 9_linux
> chmod -x 9_linux
> vi 11_linux
>
> That way 1) grub-mkconfig will run 11_linux and 2) when grub's
> upgraded you'll be able to diff 9_linux, the old 10_linux, and the new
> 10_linux.
>
> Nice. Much better than my thought making my 10_linux un-writeable.

You're welcome.