Don't place LABEL= in /etc/fstab by default, even if the filesystem has one

Since the installer has been writing LABEL to /etc/fstab by default, we should deal with upgrades somehow. I think that the best approach is simply a release note along the lines of:

 "systems installed for alpha N or beta may use LABEL in /etc/fstab - and that this could cause
  unexpected behaviour if another disk with the same label is added later.

  to find the UUID use:

        blkid -o value -s UUID -l -t LABEL=xxxx

  then put this as UUID=yyyy in /etc/fstab"

What needs to be documented in the release notes? This issue is going to be resolved for release, right?

It'll be resolved for release (I just committed a fix), but I think we should document the issue for upgraders from beta. I agreed with Scott that it wasn't critical to respin beta for this.

This bug was fixed in the package partman-target - 58ubuntu6

---------------
partman-target (58ubuntu6) jaunty; urgency=low

  * Rather than pretending that partitions have no longer been formatted
    after the partitioner is complete, reset their intended state from
    "format the partition" to "keep and use the existing data". This still
    solves the original problem reported in Debian bug #256090 while also
    stopping partitions from being needlessly reformatted if you go back to
    the partitioner after base system installation and then forward again
    (LP: #29712).
  * Don't clear partitions or complain about them not being formatted if
    they've already been formatted by a previous partitioner run.
  * Introduce partman/mount_style (choices: traditional, label, uuid) to
    allow controlling how filesystems are mounted. Default this to uuid, and
    stop using labels by default since they have unavoidable problems with
    removable disks (LP: #347817).

 -- Colin Watson <email address hidden> Fri, 27 Mar 2009 11:59:04 +0000

Release notes text added:

== Upgrades from beta use LABEL in /etc/fstab ==

Systems installed using Jaunty Alpha 5, Jaunty Alpha 6, or the Ubuntu 9.04 beta may use `LABEL=` syntax in `/etc/fstab` to identify file systems. This may cause unexpected behaviour later if another disk (such as a USB drive) is added later containing file systems with clashing labels. Unless you are sure that this is what you intend, we recommend that you switch to using universally unique identifiers (UUIDs) instead.

For example, if a file system is identified as `LABEL=home` in `/etc/fstab`, you can find the UUID as follows: {{{
blkid -o value -s UUID -l -t LABEL=home
}}} You can then replace `LABEL=home` with `UUID=output`, where `output` is the output of blkid.

Systems installed using the release candidate or final release of Ubuntu 9.04 do not have this problem.

This bug was fixed in the package installation-guide - 20081208ubuntu3

---------------
installation-guide (20081208ubuntu3) jaunty; urgency=low

  * Document pkgsel/updatedb (LP: #8195).
  * Document partman/default_filesystem.
  * Document controlling how partitions are mounted (LP: #347817).
  * Mention that Kickstart LVM configuration is now experimentally
    supported, and document the pieces currently known to be missing.
  * Update Canonical's copyright years.

 -- Colin Watson <email address hidden> Thu, 16 Apr 2009 21:56:50 +0100