Bug#824974: grub-pc: grub-probe fails on root-on-ZFS systems

[Nicolas Braud-Santoni]

Package: grub-pc
Version: 2.02~beta2-36
Severity: normal

Dear Maintainer,

On my freshly setup Stretch system, update-grub fails with the following error:

> /usr/sbin/grub-probe: error: failed to get canonical path of `/dev/vacuum-crypt'.

This led me to having no grub.cfg file (until I wrote one by hand) and
  will probably manifest itself when I upgrade the kernel.


My setup is as follows:
- /boot is on /dev/sda1 (ext4);
  it is designated by label (vacuum-boot) in /etc/fstab
- /dev/sda2 contains a LUKS volume (vacuum-crypt)
- vacuum-crypt contains a ZFS pool (vacuum) that hold the filesystem.


I am aware that ZFS support in Debian is extremely new.
My goal, in opening this bug, is to keep track of what needs to be done on Grub's
  side so that it works correctly for ZFS users.


Best regards,

  nicoo 


-- Package-specific info:

*********************** BEGIN /proc/mounts
/dev/sda1 /boot ext4 rw,nosuid,nodev,noexec,relatime,data=ordered 0 0
*********************** END /proc/mounts

*********************** BEGIN /boot/grub/grub.cfg
insmod linux
set root=(hd0,msdos1)
linux /vmlinuz-4.5.0-2-amd64 root=ZFS=vacuum/ROOT/debian boot=zfs security=apparmor
initrd /initrd.img-4.5.0-2-amd64
*********************** END /boot/grub/grub.cfg

*********************** BEGIN /proc/mdstat
cat: /proc/mdstat: No such file or directory
*********************** END /proc/mdstat

*********************** BEGIN /dev/disk/by-id
total 0
lrwxrwxrwx 1 root root  9 May 22 01:27 ata-HITACHI_HTS723232A7A364_E3834563JNZL0N -> ../../sda
lrwxrwxrwx 1 root root 10 May 22 01:27 ata-HITACHI_HTS723232A7A364_E3834563JNZL0N-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 May 22 01:27 ata-HITACHI_HTS723232A7A364_E3834563JNZL0N-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 May 22 01:27 dm-name-vacuum-crypt -> ../../dm-0
lrwxrwxrwx 1 root root 10 May 22 01:27 dm-uuid-CRYPT-LUKS1-ffe82002193847da88304475aebe7501-vacuum-crypt -> ../../dm-0
lrwxrwxrwx 1 root root  9 May 22 01:27 usb-General_1-0:0 -> ../../sdb
lrwxrwxrwx 1 root root 10 May 22 01:27 usb-General_1-0:0-part1 -> ../../sdb1
lrwxrwxrwx 1 root root  9 May 22 01:27 wwn-0x5000cca61de5b93a -> ../../sda
lrwxrwxrwx 1 root root 10 May 22 01:27 wwn-0x5000cca61de5b93a-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 May 22 01:27 wwn-0x5000cca61de5b93a-part2 -> ../../sda2
*********************** END /dev/disk/by-id

*********************** BEGIN /dev/disk/by-uuid
total 0
lrwxrwxrwx 1 root root 10 May 22 01:27 2016-04-02-20-59-26-00 -> ../../sdb1
lrwxrwxrwx 1 root root 10 May 22 01:27 5902543104507671737 -> ../../dm-0
lrwxrwxrwx 1 root root 10 May 22 01:27 87b818b8-c6ac-4802-85d5-be4b1ade3101 -> ../../sda1
lrwxrwxrwx 1 root root 10 May 22 01:27 ffe82002-1938-47da-8830-4475aebe7501 -> ../../sda2
*********************** END /dev/disk/by-uuid

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.5.0-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=, LC_CTYPE= (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages grub-pc depends on:
ii  debconf [debconf-2.0]  1.5.59
ii  dpkg                   1.18.7
ii  grub-common            2.02~beta2-36
ii  grub-pc-bin            2.02~beta2-36
ii  grub2-common           2.02~beta2-36
ii  ucf                    3.0036

grub-pc recommends no packages.

grub-pc suggests no packages.

-- debconf information:
  grub2/linux_cmdline:
* grub-pc/install_devices_empty: true
  grub2/force_efi_extra_removable: false
  grub-pc/install_devices_failed_upgrade: true
  grub-pc/postrm_purge_boot_grub: false
  grub2/device_map_regenerated:
  grub2/kfreebsd_cmdline:
* grub-pc/install_devices:
  grub2/kfreebsd_cmdline_default: quiet
  grub-pc/timeout: 5
  grub-pc/mixed_legacy_and_grub2: true
  grub2/linux_cmdline_default: quiet
  grub-pc/partition_description:
  grub-pc/install_devices_disks_changed:
  grub-pc/kopt_extracted: false
  grub-pc/install_devices_failed: false
  grub-pc/chainload_from_menu.lst: true
  grub-pc/disk_description:
  grub-pc/hidden_timeout: false