Enable Hibernate on BTRFS and LUKS using a Swap file

This is a setup on how to enable Hibernate on an LUKS encrypted Volume using a swap file. Why? Because if you are using an encrypted Swap partition, you'll have to enter your decryption password twice... and that's lame.

Tested on Manjaro.

1. Create Swap subvolume

btrfs subvolume create /swap

check: btrfs subvolume list /

2. Mount Subvolume

mount /dev/mapper/luks-79f8dd77-b3a6-4d9f-803c-0d5b3f2fe621 /swap -o subvol=/@/swap Note: Manjaro uses /@ as BTRFS root, this may vary on your setup

check: mount | grep swap

3. Add to fstab

/dev/mapper/luks-79f8dd77-b3a6-4d9f-803c-0d5b3f2fe621 /swap btrfs subvol=/@/swap,noatime,nodiratime,nodatacow,compress=no 0 0

and

/swap/swapfile swap swap defaults 0 0

4. Make swapfile

fallocate -l 64G /swap/swapfile

chmod 600 /swap/swapfile

5. Enable swap

mkswap /swap/swapfile

swapon /swap/swapfile

check: cat /proc/swaps

6. Update iniframes

in /etc/mkinitcpio.conf append resume on hooks. Note that it must be after dm-crypt and lvm (see: https://wiki.archlinux.org/title/Power_management/Suspend_and_hibernate#Configure_the_initramfs)

execute mkinitcpio -p linux614 afterwards to generate initframes. Note: 614 is the target kernel version and may differ.

7. Retrieve resume offset and swap uuid

resume offset: btrfs inspect-internal map-swapfile -r /swap/swapfile

swap uuid: blkid /swap/swapfile

Note the results.

8. Update grub config

Add GRUB_CMDLINE_LINUX="RESUME=UUID=99856d6e-4b5d-4d25-8404-aae68fd33108 RESUME_OFFSET=194570203" to /etc/default/grub with your own values from step 7 obviously...

Finally execute update-grub

krisraich/hibernation_btrfs_luks.md