[Ubuntu Server 9.10] Filesystem mounted read-only

lennartz · 08-19-2010, 06:34 AM

Hi all this is my first problem posted here so be gentle

My root filesystem is mounted read-only and I don´t know why.
It looks like it started after een `apt-get upgrade´, but that is really when I found out about it, packages didn´t install. (read only)

Also...my /home is never mounted automatically (it worked before)
And my USB drives are also never mounted automatically (worked before)
However, after I try an "mount -a" my USB drivers are mounted AND my /home is mounted BUT my root is still read-only mounted.

Things I tried:

- Running fsck on /dev/sda1: clean.
- Starting in recovery mode, all symptoms are GONE. (!)
- tried upgrading in recovery mode.
- Checking UUID´s, they match up.
- Checked dmesg
- Checked messages
- Checked sysstat

I did not alter fstab or any configuration prior to this situation.
I DID changed one thing in fstab trying to fix the problem and that is that I removed the `error = readonly` part in the parameters for SDA1.
It didn´t work.

Here is my fstab:

Code:

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=1ee0d402-eb34-44d6-932c-53fe1473b2ba /               ext3    relatime      0       1
# /home was on /dev/sda6 during installation
UUID=3be24c35-fb2a-4558-b846-a9d70d2b024d /home           ext3    relatime        0       2
# /tmp was on /dev/sda8 during installation
UUID=39bf57d1-2e25-4533-a517-87271e8f5922 /tmp            ext3    relatime        0       2
# /var was on /dev/sda7 during installation
UUID=a6bf5b3d-be11-413d-bc68-2b0b2bd54bf9 /var            ext3    relatime        0       2
# swap was on /dev/sda5 during installation
UUID=81ea86d5-f72c-487f-8e34-eef340f149be none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec,utf8 0       0
/dev/fd0        /media/floppy0  auto    rw,user,noauto,exec,utf8 0       0

# Section added for External USB Hard drives.
# The labels are needed to pevent mixup in mounts and device order.
# DO NOT USE device files instead of the labels. /LZ

LABEL=usb1      /storage/usb1   auto    rw,user,auto,exec       0       3
LABEL=usb1copy  /storage/usb1copy   auto    rw,user,auto,exec       0       3
LABEL=usb2      /storage/usb2   auto    rw,user,auto,exec       0       3
LABEL=usb2copy  /storage/usb2copy   auto    rw,user,auto,exec       0       3

update:
Just before the login prompt I get these messages:

Code:

umount: /var (device is busy)
umount: /tmp (device is busy)
umount: /dev (device is busy)
umount: /var/run (device is busy)

I spotted these on the console itself, I work over SSH so..

any suggestion is welcome as I´am a newbie on Linux.

aeternitas · 08-22-2010, 02:10 AM

A few questions, if I might...

First, what distro/version are you currently using?

Second, had you made any changes prior to the mentioned apt-get upgrade (software, hardware, and so on) that you can recall?

Do you typically work as yourself (using sudo for administrative tasks like updates and the like), or have you unlocked root for routine use?

Last, when you, say, insert a USB drive and it doesn't auto-mount for you, does they system just sit idly as if nothing has been attached, or does it throw an error at you? If an error is thrown, what is it?

The thing that gets me is the fact that umount of /var, /tmp, /dev/ and /var/run is being attempted...it doesn't strike me as normal (I've never seen it happen myself).

lennartz · 08-22-2010, 07:31 AM

Quote:

Originally Posted by aeternitas

A few questions, if I might...

First, what distro/version are you currently using?

Code:

lennart@hermes:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=9.04
DISTRIB_CODENAME=jaunty
DISTRIB_DESCRIPTION="Ubuntu 9.04"

Quote:

Second, had you made any changes prior to the mentioned apt-get upgrade (software, hardware, and so on) that you can recall?

No, that´s the strange thing. The apt-get upgrade seem to have triggered these events.
When I boot, /home is gone. my USB drives are not mounted and my root is mounted read-only.
If I run a `mount -a`. /home is mounted again. My usb drives are mounted (BUT DO NOT SHOW UP IN MTAB or DF, but DO in /PROC/MOUNTS) and my root is STILL mounted read-only.
All of the symptoms are gone and work right away after boot when I use recovery mode in GRUB. it just works like it alway´s did from there.

Quote:

Do you typically work as yourself (using sudo for administrative tasks like updates and the like), or have you unlocked root for routine use?

I use SUDO.

Quote:

Last, when you, say, insert a USB drive and it doesn't auto-mount for you, does they system just sit idly as if nothing has been attached, or does it throw an error at you? If an error is thrown, what is it?

I don´t use the auto-mount I think?. I have entries in my fstab for the USB drives and they are alway´s connected.

Quote:

The thing that gets me is the fact that umount of /var, /tmp, /dev/ and /var/run is being attempted...it doesn't strike me as normal (I've never seen it happen myself).

I don´t get it either.
I checked /var/log/messages for errors.
The only thing that might mean something (not sure

?

Code:

Aug 22 12:44:30 hermes kernel: [    3.250320] Write protecting the kernel read-only data: 1544k

Also searched /var/log/messages for umount messages. none found.

btmiller · 08-22-2010, 03:41 PM

Try typing dmesg and see if you have any errors when mounting your root partition. Usually a filesystem is mounted read-only when there's some sort of error or problem with tghe filesystem or the underlying hardware. What I usually do is reboot the computer into single user mode (or even better, boot off of a LiveCD) and then manually run fsck ion the affected partition, fixing any errors that might crop up.

Doing normal day-to-day work (even as root) should not cause filesystem corruption or cause the partition to be remounted read-only (well, unless you do something truly dumb like write directly to a raw disk device). Sounds to me like there's a hardware or filesystem issue. Maybe your disk is starting to go bad?

One other thing you can do is run:

tune2fs -l <your root partition>

Replaacing <your root partition> with the actual device node of the root partition. This will see what state the filesystem thinks that it is in.