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[REOPENED] content of /etc/mtab: number for root?
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freifunk_connewitz
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PostPosted: Mon Aug 11, 2014 7:47 am    Post subject: [REOPENED] content of /etc/mtab: number for root? Reply with quote

Hi,
it's been a while since this occurs: when issueing "mount" or "cat /etc/mtab" to see the actually mounted filesystems, it prints as the first two lines:

Quote:

rootfs on / type rootfs (rw)
812 on / type ext3 (rw,noatime,nodiratime,commit=0)


what's with this "812"? shouldnt it say something like "/dev/sdaX"?

I found nothing bout it in the mount or fstab documentation...

Cheers,
FFCW


Last edited by freifunk_connewitz on Sun Jul 05, 2015 1:04 pm; edited 2 times in total
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Demonking
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PostPosted: Mon Aug 11, 2014 1:14 pm    Post subject: Reply with quote

Hello freifunk_connewitz,

the first value could also be a virtual Filesystem from the Kernel like proc,cgroup_root or something like that.
This would look like this :

Code:

proc on /proc type proc (rw,relatime)
tmpfs on /run type tmpfs (rw,nosuid,nodev,relatime,size=817364k,mode=755)
cgroup_root on /sys/fs/cgroup type tmpfs (rw,nosuid,nodev,noexec,relatime,size=10240k,mode=755)


But the 812 is strange, have you checked your fstab?

Maybe look what this command returns :

Code:
cat /proc/filesystems


Greetz

Demonking
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freifunk_connewitz
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PostPosted: Mon Aug 11, 2014 2:09 pm    Post subject: Reply with quote

Hi Demonking,

thanks for your answer.

Demonking wrote:

the first value could also be a virtual Filesystem from the Kernel like proc,cgroup_root or something like that.


Yeah, I do have all those mounted, too.

Quote:
But the 812 is strange, have you checked your fstab?


Most def. There, everything looks like it should.

Quote:
Maybe look what this command returns :
Code:
cat /proc/filesystems



- a long list of possible filesystems.
By the way, I have the same thing on a laptop with a quite similar installation on it. Except that the number isn't 812 but something else.

What I first thought was that it could be some new feature of OpenRC or LVM or dm-crypt. But on both machines, not root, but only the home dir is encrypted, and I do not use use logical volumes.

LVM had to be installed anyway, because lilo, cryptsetup and some others depend on it. For whatever reason.

So, nobody has ever seen such a mtab?

Cheers,
freifunk connewitz
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krinn
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PostPosted: Mon Aug 11, 2014 7:00 pm    Post subject: Reply with quote

Hi, victim #2 :)
Look here, you'll get some explain about what is the number...
https://forums.gentoo.org/viewtopic-t-996732.html

Nobody have the solve to get back a saner naming. Waiting to see if more users get affected.
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freifunk_connewitz
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PostPosted: Tue Aug 12, 2014 10:19 am    Post subject: Reply with quote

krinn,

thanks for the hint. that's the thread I was looking for.
fortunately for me, my good old LILO indeed does complain about "812 not found", too, when updating the bootsector, but still continues its job and succeeds.

so, should there be a bug filed against udev?

cheers,
ffcw
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krinn
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PostPosted: Tue Aug 12, 2014 10:35 am    Post subject: Reply with quote

Without really knowing my feelings are more a kernel problem than udev (because /proc is not handle by udev but kernel)
But as you and the other user didn't expose any udev or kernel version. Things get hard to debug without info.

You indeed should filebug that (as i'm sure victim #3 exists but didn't notice it yet)
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NeddySeagoon
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PostPosted: Tue Aug 12, 2014 4:31 pm    Post subject: Reply with quote

krinn,

... behind you :)
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freifunk_connewitz
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PostPosted: Mon May 11, 2015 6:02 pm    Post subject: Reply with quote

in my case some update silently solved the problem. /dev/root is displayed correctly in /proc/self/mountinfo, /proc/self/mounts or df -h. no hex numbers instead of /dev/root anymore.

my current setup:
lilo-24.0-r1
openrc-0.13.11
kernel 3.18.11

thanks for the help
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bstaletic
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PostPosted: Mon May 11, 2015 6:17 pm    Post subject: Reply with quote

A few weeks ago I had the same problem, now everything says /dev/root except "mount". "mount" shows 823.

EDIT:
Kernel 4.0.2 (deblobed)
Lilo 24.1
eudev 3.0
openrc 0.15.1
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krinn
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PostPosted: Mon May 11, 2015 7:55 pm    Post subject: Reply with quote

NeddySeagoon wrote:
krinn,

... behind you :)

From that time, i was really happy by that comment...

Now that some time has pass, i'm not really feeling really safe reading it anymore :)


Happy for you that your problem is solved freifunk_connewitz, thanks for the solved title edit, other users will enjoy your hint.
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freifunk_connewitz
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PostPosted: Sun Jul 05, 2015 1:01 pm    Post subject: Reply with quote

this unfortunately has to be "reopened".

bstaletic, same here: everything says /dev/root except "mount". "mount" shows (in my case) 812.
kernel-3.18.12-gentoo
openrc-0.16.4
sys-fs/udev-216
virtual/udev-215
lilo 24.0-r1

and on top of it: on a freshly installed machine with kernel 4.0.5 everything (/proc/mount{s,info} and 'mount') shows the wrong info again: 803 instead of /dev/root (or /dev/sda3).

setup:
openrc 0.17
udev 216
virtual/udev 215
lilo 24.0-r1
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freifunk_connewitz
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PostPosted: Sun Jul 05, 2015 1:56 pm    Post subject: Reply with quote

as discussed here: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=766920, this bug disappears if you boot with UUID in your lilo.conf instead of /dev/sdXX. unfortunately, this is not an option for me because it only worked if I also began to use an initrd/initramfs. what I won't.

but krinn, Neddy, or anybody else, would you agree that it is lilo where I should file a bug report?
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bstaletic
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PostPosted: Sun Jul 05, 2015 4:12 pm    Post subject: Reply with quote

Isn't bootloader supposed to only load the kernel?
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steveL
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PostPosted: Sun Jul 05, 2015 7:42 pm    Post subject: Reply with quote

You should still be able to use PARTUUID as that's done by the kernel, and does not require userland, nor FS support.

As for where the bug is, I'd be inclined to blame the recent "let's change mount from userland" "work" done by distro developers, specifically debian wrt mount/libmount/utab, and ofc we're following along "because coreutils".
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freifunk_connewitz
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PostPosted: Tue Jul 07, 2015 10:05 am    Post subject: Reply with quote

SteveL, thanks for the hint, but lilo considers a direct PARTUUID entry in lilo.conf like
Code:
root=/dev/disk/by-partuuid/xxxxx

as illegal.

but we can use instead:
Code:
append="root=/dev/by-partuuid/xxxxx"


the funny thing is, if I do that, the output of mount or /proc/self/mountinfo shows no hex numbers anymore, but:
Quote:
PARTUUID=xxxxx / ext4 ...


obviously, lilo uses exactly the information you give it with the append option above. having seen that, I thought, well, why not just tell lilo to use what I wanted there from the beginning, the real device path. so I changed lilo.conf again, replaced the PARTUUID-part by /dev/sda3 (thats where my root fs lives), rebooted, was happy.

this is my working lilo.conf (when booting the 'test' entry):

Quote:
# $Header: /var/cvsroot/gentoo-x86/sys-boot/lilo/files/lilo.conf,v 1.2 2004/07/18 04:42:04 dragonheart Exp $
# Author: Ultanium

#
# Start LILO global section
#

compact
lba32

# MBR to install LILO to:
boot = /dev/sda

menu-scheme=Wb
prompt
timeout=5
delay = 50
vga = normal

# End LILO global section
#

#
# Linux bootable partition config begins
#
default = Gentoo

image = /boot/vmlinuz-4.0.5-gentoo
root = /dev/sda3
label = Gentoo
read-only # read-only for checking

image = /boot/vmlinuz-4.0.5-gentoo
append="root=/dev/sda3"
label = test
read-only # read-only for checking


and this is the first output line of cat/proc/mountinfo:
Quote:
/dev/sda3 / ext4 rw,noatime,data=ordered 0 0


Finally, SteveL, I'm sorry, but I don't really get your last sentence. I just don't know enough about the development details. Do you mean it's gonna be a Gentoo bug?
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