[Bug 684280] Re: casper toram forgets to disconnect loop device

scmarko 684280 at bugs.launchpad.net
Thu Apr 4 07:04:32 UTC 2024


This should be fixed, because when you boot an ISO file from your hard
drive and load Ubuntu to RAM, you are not able to do any repartitioning,
installing etc to the hard drive from where the ISO was loaded from when
it stays mounted. I have tested this on a Ubuntu installation with LVM
hard drive and once I applied the changes to the initrd file of the
Ubuntu ISO, then I was able to successfully run the following commands:

losetup -d /dev/loop0
umount /isodevice

After that I was able to repartition the hard drive and install Ubuntu
from RAM to hard drive. But this adds too much complexity to the end
user if needing to unpack the ISO file and then modify initrd if needing
to use Ubuntu like this.

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https://bugs.launchpad.net/bugs/684280

Title:
  casper toram forgets to disconnect loop device

Status in casper package in Ubuntu:
  Triaged
Status in Baltix:
  Invalid

Bug description:
  Binary package hint: ubiquity

  Ubiquity cannot install if you are booting LiveCD directly from ISO.

  Booting directly from GRUB to the ISO, mounts the ISO to /isodevice.

  Ubiquity will not install (even if on separate disk) if this is not
  unmounted.

  The result being that one cannot install Ubuntu in this method.

  This method can be used to create a recovery partition or a multi-usb
  bootable drive. For more explanation on how to do this:

  ========== START ==========

      * Run the following commands which will create the directory
  /boot/iso and download the iso file to that directory.

  $ sudo -s
  # mkdir /boot/iso
  # cd /boot/iso
  # wget http://releases.ubuntu.com/maverick/ubuntu-10.10-desktop-i386.iso

      * Add a custom menu entry in GRUB2 configuration file. Edit
  /etc/grub.d/40_custom as root to look like this:

  #!/bin/sh
  echo "Adding 40_custom." >&2
  exec tail -n +3 $0

  menuentry "Maverick CD Image ISO" {
  set isofile=/boot/iso/ubuntu-10.10-desktop-i386.iso
  loopback loop (hd0,1)$isofile
  linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile noprompt noeject
  initrd (loop)/casper/initrd.lz
  }

      * Afterwards, run update-grub for the changes to be propagated to
  /boot/grub/grub.cfg

  # update-grub
  Generating grub.cfg ...
  Found linux image: /boot/vmlinuz-...
  Found initrd image: /boot/initrd.img-...

  ========== STOP ==========

  ================== Workaround =================

  After casper copy to ram , it need to disconnect the loop device and
  unmount

  losetup -d /dev/loop0
  umount /isodevice

  ===========================================

  The result of booting from the ISO directly from GRUB, is that the CD
  is that the partition where the ISO is located is mounted to
  /isodevice.

  Ubiquity seems to want to have control of all disks and unmount all
  disks before it starts installing. In the images here you see the
  example is sda2 for / and sda for the MBR. I have also tried this with
  a secondary disk where sdb1 was to be used for / and sdb for the MBR
  and ubiquity still complained that it had to to unmount /isodevice,
  even though it is on sda1. Doesn't make much sense to unmount a disk
  if you will not be editing any part of it.

  ProblemType: Bug
  DistroRelease: Ubuntu 10.10
  Package: ubiquity 2.4.8
  ProcVersionSignature: Ubuntu 2.6.35-22.33-generic 2.6.35.4
  Uname: Linux 2.6.35-22-generic i686
  NonfreeKernelModules: wl
  Architecture: i386
  Date: Thu Dec  2 16:34:42 2010
  LiveMediaBuild: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
  ProcEnviron:
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: ubiquity

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