[Bug 1489855] Re: Change to mount sequence order breaks persistence on casper-rw partitions

Wed Apr 15 14:41:39 UTC 2020

> So is there still a bug with 20.04 as you suggest?

At the time I posted my comment, yes there absolutely was.

A regression had been introduced in the daily 20.04 builds, that made
persistence consistently fail on some machines. This was confirmed by
other people too.

Now, since I added my reports onto it, the most problematic aspect of
this issue has now been fixed, though there still exist a non-breaking
corollary issue (introduction of a new 'writable' name for persistent
partitions) that a few of us would like to see addressed.

It's all in the bug report(s) I linked to.

> If the bug was only squashed with 19.10 are you going to give up on
persistence for Rufus and just wait for the bug to get fixed?

That was a consideration I had, since, at the time, it looked to me like
Ubuntu made little effort to backport the bugfix into 18.04 (which, I
will assert, they should have if they actually cared about their LTS
users) and had suddenly broken persistence for 20.04 again. But with
20.04 being somewhat usable for persistence again, the only major issue
that persists is that 18.04 hasn't been fixed, which is the precise
reason we are having this "discussion".

> Perhaps another five years.

And that is exactly my issue.

People who should have made a bigger deal of this issue (including
asking for a 18.04 backport) appear to have just been content to
declare, as you are attempting to do, that the manner in which Rufus and
other methods that happen to create persistent partitions that trigger
this bug, are "unnatural", which is simply ridiculous since it is really
the most straightforward way to do it. Therefore, instead of helping
raise heat so that maintainers realised that this was a problem for many
many users, helped ensure that the issue was left unaddressed for years
instead, leading us precisely into the situation we are now, with user
after user reporting `mount: mounting /cow on /root failed: Invalid
argument` issues when they try to use 18.04 with persistence.

> Seems better to me to work with what we have rather that wait for a
perfect world.

Seems better to me to have people understand the ramification of trying
to brush an issue under the carpet and/or the negative impact that an
unaddressed bug can have for Ubuntu users.

I'm pretty sure that, if the bug was with Rufus, we'd see quite very
different tune from you, with something along the line of "How can you
pretend to care about your users if you are going to leave this Rufus
bug unaddressed for years?".

So maybe you want to make an attempt to review the situation a bit more
objectively at last.

Plenty of users of Ubuntu are affected by this issue still, since 18.04
has not backported this bugfix. And you should really know this, because
you've been seeing that issue pop up in askubuntu over and over again.
So, if you actually care about Ubuntu users, you might want to stop this
charade of trying to point the finger at anything but the actual bug,
and instead, contribute to this report to help the maintainers realize
that, maybe, the fix for this is something that they should have
backported to 18.04, because it has been ending up affecting many many
first time users of Ubuntu.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to casper in Ubuntu.
https://bugs.launchpad.net/bugs/1489855

Title:
  Change to mount sequence order breaks persistence on casper-rw
  partitions

Status in casper package in Ubuntu:
  Fix Released

Bug description:
  the system boots fine when using a casper-rw FILE but drops to a
  busybox when using a partition

  the short log would be:
  ___________________________________________________
  Begin: Running /scripts/casper-premount ... done.
  done.
  umount: can't umount /cdrom: Device or resource busy
  Warning: Unable to find the persistent home medium
  umount: can't umount /cdrom: Device or resource busy
  Warning: Impossible to include the casper-sn Snapshot
  umount: can't umount /cdrom: Device or resource busy
  Warning: Impossible to include the home-sn Snapshot
  done.
  ___________________________________________________

  removing the "persistence" keyword from the syslinux.cfg works and the live usb drive boots just fine.
  using a persistence file instead of the partition and the usb drive boots just fine.

  i found older bug reports concerning the same problem but the fix
  proposed in 2010 is already integrated into the script "casper".

  so i started the flashdrive with the casper debug= option and i see
  the following (after probing several other devices it finally finds
  the right device and partition (sdb3)

  ___________________________________________________

  + cow_backing_mp=/cdrom
  + [ -e /cdrom/casper-rw ]
  + umount /cdrom
  + sys2dev /sys/block/sdb/sdb3
  + sysdev=/block/sdb/sdb3
  + udevadm info -q name -p /block/sdb/sdb3
  + echo /dev/sdb3
  + devname=/dev/sdb3
  + /sbin/blkid -s LABEL -o value /dev/sdb3
  + [ casper-rw = casper-rw ]
  + echo /dev/sdb3
  + return
  + cowprobe=/dev/sdb3
  + [ -b /dev/sdb3 ]
  + cowdevice=/dev/sdb3
  + get_fstype /dev/sdb3
  + local FSTYPE
  + local FSSIZE
  + fstype
  + eval FSTYPE=ext4 FSSIZE=8458862592
  + FSTYPE=ext4 FSSIZE=8458862592
  + [ ext4 != unknown ]
  + echo ext4
  + return 0
  + cow_fstype=ext4
  + cow_mountopt=rw,noatime
  + mount -t ext4 -o rw,noatime /dev/sdb3 /cow
  + [ ! -d /cow/upper ]
  + mkdir -p /cow/upper
  + continue
  + continue
  + mkdir -p /cow/work
  + [ -f /cow/format ]
  + [ DEFAULT = DEFAULT ]
  + modprobe -q -b overlay
  + grep -q ^overlay$
  + cut -f2 /proc/filesystems
  + UNIONFS=overlay
  + break
  ___________________________________________________

  this looks fine to me.. it looks like it recognizes everything .. it's
  ext4 .. label casper-rw.. it's mounting it...

  a little bit further down in the loooong log file it states the
  following:

  ______________________________________________

  + cow_backing_mp=/home-rw-backing
  + [ -e /home-rw-backing/home-rw ]
  + umount /home-rw-backing
  + sys2dev /sys/block/sdb/sdb3
  + sysdev=/block/sdb/sdb3
  + udevadm info -q name -p /block/sdb/sdb3
  + echo /dev/sdb3
  + devname=/dev/sdb3
  + /sbin/blkid -s LABEL -o value /dev/sdb3
  + [ casper-rw = home-rw ]
  + get_fstype /dev/sdb3
  + local FSTYPE
  + local FSSIZE
  + fstype
  + eval FSTYPE=ext4 FSSIZE=8458862592
  + FSTYPE=ext4 FSSIZE=8458862592
  + [ ext4 != unknown ]
  + echo ext4
  + return 0
  + [ ext4 = vfat ]
  + homecow=
  + [ -b ]
  + [ n != y ]
  + log_warning_msg Unable to find the persistent home medium
  + _log_msg Warning: Unable to find the persistent home medium\n
  + [ n = y ]
  + printf Warning: Unable to find the persistent home medium\n
  Warning: Unable to find the persistent home medium
  __________________________________________________________

  a warning about the home medium is shown in both cases (file and partition) but the persistence file works never the less..

  my system:  

  kubuntu linux 15.10 beta1

  uname -a
  Linux wald 4.1.0-3-generic #3-Ubuntu SMP Tue Jul 28 12:25:10 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/casper/+bug/1489855/+subscriptions