[Bug 2110050] Re: grub-mkconfig fails with ZFS when /etc/fstab was touched: find: ‘mount: (hint) your fstab has been modified, but systemd still uses[…]/tmp/zfsmnt.2a85H0/boot’: No such file or directory

[Louis Sautier]

Could you please backport this util-linux patch to fix the bug?
https://github.com/util-linux/util-
linux/commit/cdc8b265bff5ee1ebd496aa1d6211e4ba120f766

** Tags added: patch

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Title:
  grub-mkconfig fails with ZFS when /etc/fstab was touched: find:
  ‘mount: (hint) your fstab has been modified, but systemd still
  uses[…]/tmp/zfsmnt.2a85H0/boot’: No such file or directory

Status in grub2 package in Ubuntu:
  New

Bug description:
  Hello,
  If /etc/fstab is newer than /run/systemd/systemd-units-load, mount emits a hint to STDOUT.
  This causes the following mount call to return a message which is later interpreted as a path:
  https://git.launchpad.net/~ubuntu-core-dev/grub/+git/ubuntu/tree/debian/patches/ubuntu-zfs-enhance-support.patch?h=debian/2.12-5ubuntu5.3#n180
  https://git.launchpad.net/~ubuntu-core-dev/grub/+git/ubuntu/tree/debian/patches/ubuntu-zfs-enhance-support.patch?h=debian/2.12-5ubuntu5.3#n472
  To reproduce:
  * Install Ubuntu 25.04 with a /boot and a / dataset:
    root at test:~# zfs list
    NAME      USED  AVAIL  REFER  MOUNTPOINT
    zp0      2.73G   212G    24K  none
    zp0/zd0   118M   906M   118M  /boot
    zp0/zd1  2.61G   212G  2.61G  /
  * Run "touch /etc/fstab"

  root at test:~# grub-mkconfig 
  Sourcing file `/etc/default/grub'
  Generating grub configuration file ...
  […]
  ### BEGIN /etc/grub.d/10_linux_zfs ###
  find: ‘mount: (hint) your fstab has been modified, but systemd still uses\n       the old version; use 'systemctl daemon-reload' to reload.\n/tmp/zfsmnt.f2yDJq/boot’: No such file or directory
  ### END /etc/grub.d/10_linux_zfs ###
  […]

  util-linux's upstream might change mount's behavior to skip the hint
  when STDOUT is not a TTY, see https://github.com/util-linux/util-
  linux/issues/3558#issuecomment-2854381281

  In the meantime, I think it might be prudent to discard output from
  all mount calls from /etc/grub.d/10_linux_zfs, or to use upstream's
  10_linux for ZFS too.

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