unable to run e2fsck

[stan]

I copied back to the list.

On Wed, 20 May 2015 19:37:18 +0300
Angelo Moreschini <mrangelo.fedora at gmail.com> wrote:

> I tried still fsck, this time using System CD Rescue ....
> 
> After I get the prompt from the terminal (inside the System CD Rescue
> environment)
> 
> I tried this:  /dev/sd*..
> and I got
> /devsda   /dev/sda1   /dev/sda2
> 
> After I asked for mounted devices and no one of the devices /dev/sda*
> was listed there..
> 
> As well this answer, I yet unmounted /dev/sda2 (for security):
> ------------
> # umount /dev/sda2
> umount : /dev/sda2 : not mounted
> ------------
> 
> Finally I tried  e2sfck :
> ------------
> # e2fsck /dev/sda2
> 
> */dev/sda2 is in use .*
> *e2fsck Cannot continue, aborting.*
> ------------
> 
> What this means ?
> 
> 
> With my little experience I think that System CD Rescue load an image
> of the kernel in the RAM (/proc directory ??)
> and because this we can use Linux commands also when the filesystem
> is NOT mounted.
> 
> In this way we are able to explore the hardware environment of the
> computer...
> 
> I cannot understand what is the reason of the message :
> ------------
> 
> */dev/sda2 is in use .e2fsck Cannot continue, aborting.*
> ------------
> * when  /dev/sda2 is unmounted..*
> 
> 
> Can I have an explication ??

My understanding is like yours.  Basically, you are running a live CD,
completely independent of the installed system.

What does
cat /etc/mtab  show?
If /dev/sda2 is being held by some process in the rescue OS that is
accessing it, it should show up as an active partition in the mtab.

What happens if you do
umount /mnt/sysimage  ?
Does the  cat /etc/mtab  command show anything different?

Do you have more than one disk?  Is it possible that the rescue CD is
ordering them differently than you think, and what it is
calling /dev/sda is actually /dev/sdb?  Better to use block IDs to
identify disks these days.  The command /sbin/blkid will show them to
you.