zfs: update to 2.1.6.

[zdykstra]

Testing the changes

• I tested the changes in this PR: YES

This could use testing by users that do NOT have root-on-ZFS for their ZFS usage. Tested locally on x86_64, no native encryption, root-on-ZFS.

@ahesford @Vaelatern

[ahesford]

Builds and boots fine on an RPi 4B. I have no systems that don't have ZFS roots on which to test.

[Vaelatern]

I've got some pools that are not on root, but they are all very simple setups or not suitable for test

[ahesford]

I think the main issue motivating tests for non-ZFS roots was the earlier breakage in the dracut module that prevented people with the zfs module installed from booting with other root filesystems.

[sgn]

Linux 5.19.12 / on ext4 with one disk in zfs, booted. I will do more testing tomorrow.

depmod: WARNING: could not open modules.order at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin.modinfo at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory

[zdykstra]

Linux 5.19.12 / on ext4 with one disk in zfs, booted. I will do more testing tomorrow.

depmod: WARNING: could not open modules.order at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin.modinfo at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory

Do you have kernel 5.18.19 installed on your machine? There's a flaw somewhere that leaves dangling directories in /lib/modules, and that confuses Dracut.

[sgn]

Linux 5.19.12 / on ext4 with one disk in zfs, booted. I will do more testing tomorrow.

depmod: WARNING: could not open modules.order at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory
depmod: WARNING: could not open modules.builtin.modinfo at /tmp/dracut.qnXMbR/initramfs/lib/modules/5.18.19_1: No such file or directory

Do you have kernel 5.18.19 installed on your machine? There's a flaw somewhere that leaves dangling directories in /lib/modules, and that confuses Dracut.

You're right, I have it removed.