Re: [gentoo-user] fstab/mount riddle...how?

Meino.Cramer@×××.de wrote:

> Hi,
>
> ...still fiddling with Linux on my ASUS MeMO Pad 7... ;)
>
> Current status:
> SDCard:
> Back from extFAT (toooooo slllooooooww) to FAT32
> On this SDCard two file, each 4GB in sizse and formatted ext4
> One conatins currently the complete Linux (used as chroot environment)
> The second one contains a copy of /usr (that is, the second image
> contains /usr - not only its ontents).
>
> I finally want to get rid of the /usr on the first file to get more
> space for upgrades, intstallations and such.
>
> While using the chrooted environment (completly booted from the first
> file) I did
>
> mount /dev/sdcard /mnt
> losetup /dev/loop(x) /mnt/frstfile.img
> mount  /dev/loop(x) /image
> mount --bind /image/usr /usr

Why don't you use /usr as mount point for /dev/loop(x)?
AFAIK it does not matter that /usr already contains something.
 
> This way the /usr of the first image file was somehow
> "knocked off" and the (identical) /usr of the second image
> file tooks its place.

This should IMHO also be the case when you mount /dev/loop(x) directly
to /usr. But I haven't tested this. Maybe I'm wrong.
 
> It works so far.
>
> Now the problem:
> How can I manipulate /etc/fstab (and may be others) in a
> way that /usr of the second image file permanently replaces
> /usr of the first image file AND gives me the change to remove
> /usr of the first image file?

I think, as long as you have mounted something to /usr, you will have no 
access to the "old" content of /usr. It is covered by the new mount.

But why don't you just delete the content of /usr before you using it as 
mount point. I suggested this already in my last post.

I haven't tested this by myself so maybe I'm wrong, but I think as long as 
you do this in single user mode from a simple text console with bash, it 
should work. System components are normally not living under /usr, so 
nothing should fail when you do this.

--
Regards
wabe