[Bug 1527727] Re: grub-probe for zfs assumes all devices prefix with /dev, ignoring /dev/disk/...

[Scott Moser]

>From the install log you can see that we install grub2 at 2.02~beta2-36ubuntu3.17.
   ..
   Unpacking grub2-common (2.02~beta2-36ubuntu3.17)
   ..


'dpkg-reconfigure grub-pc' and 'grub-install /dev/vda' are run

And also:

  run-parts: executing /etc/kernel/postinst.d/zz-update-grub 4.4.0-116-generic /boot/vmlinuz-4.4.0-116-generic
  Generating grub configuration file ...
  Found linux image: /boot/vmlinuz-4.4.0-9025-euclid
  Found initrd image: /boot/initrd.img-4.4.0-9025-euclid
  Found linux image: /boot/vmlinuz-4.4.0-116-generic
  Found initrd image: /boot/initrd.img-4.4.0-116-generic
    /run/lvm/lvmetad.socket: connect failed: No such file or directory

Then during boot we see

[    0.000000] Command line:
BOOT_IMAGE=/ROOT/zfsroot@/boot/vmlinuz-4.4.0-9025-euclid
root=ZFS=rpool/ROOT/zfsroot ro console=ttyS0

So we have successfully booted from root on a zfs system.





** Tags removed: verification-needed verification-needed-xenial
** Tags added: verification-done verification-done-xenial

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https://bugs.launchpad.net/bugs/1527727

Title:
  grub-probe for zfs assumes all devices prefix with /dev, ignoring
  /dev/disk/...

Status in grub:
  Unknown
Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2-signed package in Ubuntu:
  Fix Released
Status in zfs-linux package in Ubuntu:
  Fix Released
Status in grub2 source package in Xenial:
  Fix Committed
Status in grub2-signed source package in Xenial:
  Fix Committed
Status in zfs-linux source package in Xenial:
  Fix Released

Bug description:
  [Impact]
  Installs over ZFS where a ZFS disk is expected to be used as a root device.

  [Test case]
  - Run update-grub on a system with a ZFS root filesystem.

  [Regression Potential]
  Installs relying on the current broken behavior to avoid listing other operating systems in grub menu may find that new entries are added.

  ---

  update-grub runs /usr/sbin/grub-probe

  Without libzfslinux support compiled in, /usr/sbin/grub-probe runs
  ["zpool", "status", poolname] to find out ZFS info.

  zpool responds with device names as used at (I think!) pool creation
  time. Often, this is /dev/disk/by-id/... names, without the path.

  grub-probe then parses the output, and takes the names of devices, and
  if they do not start with a "/", it prepends "/dev/".

  It then tests the existence of the path name of the device. it fails.

  grub-probe then returns  something like

  /usr/sbin/grub-probe: error: failed to get canonical path of `/dev
  /ata-ST31000333AS_99999999-part1'.

  The actual path is of course /dev/disk/by-
  id/ST31000333AS_99999999-part1

  It can prepend smarter than "/dev" or it can understand ZFS natively,
  to fix the problem.

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