Problems locating kernels on subvolumes in btrfs

[khumarahn]

My grub config references 4.16.4, 5.4.8 (current) and 5.4.10. But eclean-kernel removes all but current. Root partition is in a btrfs, which might be a problem.

# eclean-kernel -a
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-5.4.8-gentoo
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-5.4.8-gentoo
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-5.4.8-gentoo
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-4.16.6-gentoo
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-4.16.6-gentoo
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-4.16.6-gentoo.old
Note: referenced kernel does not exist: /boot/root-subvolume/boot/vmlinuz-4.16.6-gentoo.old
Preserving currently running kernel (5.4.8-gentoo)
* Removing kernel 4.16.6-gentoo.old (not referenced by bootloader (grub2))
- /boot/vmlinuz-4.16.6-gentoo.old
- /boot/System.map-4.16.6-gentoo.old
- /boot/config-4.16.6-gentoo.old
* Removing kernel 4.16.6-gentoo (not referenced by bootloader (grub2))
- /boot/vmlinuz-4.16.6-gentoo
- /boot/System.map-4.16.6-gentoo
- /boot/config-4.16.6-gentoo
- /lib64/modules/4.16.6-gentoo
- /usr/src/linux-4.16.6-gentoo
* Removing kernel 5.4.10-gentoo (not referenced by bootloader (grub2))
- /boot/vmlinuz-5.4.10-gentoo
- /boot/System.map-5.4.10-gentoo
- /boot/config-5.4.10-gentoo
- /lib64/modules/5.4.10-gentoo
- /usr/src/linux-5.4.10-gentoo
Removed 3 kernels

app-admin/eclean-kernel-0.4.3::gentoo was built with the following:
USE="" ABI_X86="(64)" PYTHON_TARGETS="python2_7 python3_6 (-python3_7)"