repart: Btrfs expects `--rootfs` with `--compression`

[korewaChino]

systemd version the issue has been seen with

258.1

Used distribution

Fedora/Ultramarine 43

Linux kernel version used

6.17.6-0.fc43.x86_64

CPU architectures issue was seen on

x86_64

Component

systemd-repart

Expected behaviour you didn't see

repart formats Btrfs volume properly with compression options

Unexpected behaviour you saw

mkfs.btrfs fails with ERROR: --compression must be used with --rootdir

Steps to reproduce the problem

Run with the following configs:

[Partition]
Type=esp
Format=vfat
SizeMinBytes=512M
SizeMaxBytes=512M
MountPoint=/boot/efi:umask=0077,shortname=winnt
# This path is actually relative; see man repart.d at --copy-source option
CopyFiles=/boot/efi/:/

[Partition]
Format=ext4
SizeMinBytes=1G
Weight=100
SizeMaxBytes=2G
MountPoint=/boot/:defaults
# This path is actually relative; see man repart.d at --copy-source option
CopyFiles=/boot:/
ExcludeFiles=/boot/efi
Type=xbootldr

[Partition]
MountPoint=/:subvol=/,compress=zstd:1
MountPoint=/home:subvol=/home,compress=zstd:1
DefaultSubvolume=/
Type=root
Compression=zstd
ExcludeFiles=/boot/
Format=btrfs
CopyFiles=/:/
Subvolumes=/ /home
CompressionLevel=1

Additional program output to the terminal or log subsystem illustrating the issue

/run/readymade-install/50-root.conf:2: Too many arguments in MountPoint=, ignoring: /:subvol=/,compress=zstd:1
/run/readymade-install/50-root.conf:3: Too many arguments in MountPoint=, ignoring: /home:subvol=/home,compress=zstd:1
Applying changes to /dev/vda.
Wiped block device.
Discarded entire block device.
Successfully wiped file system signatures from future partition 0.
Successfully wiped file system signatures from future partition 1.
Successfully wiped file system signatures from future partition 2.
Formatting future partition 0.
mkfs.fat 4.2 (2021-01-31)
/dev/loop1 successfully formatted as vfat (label "ESP", uuid 0efd53cf)
Successfully formatted future partition 0.
Populating vfat filesystem.
Successfully populated vfat filesystem.
Syncing future partition 0 contents to disk.
Formatting future partition 1.
mke2fs 1.47.3 (8-Jul-2025)
Discarding device blocks:      0/262144             done                            
Creating filesystem with 262144 4k blocks and 65536 inodes
Filesystem UUID: 5dc11ee2-fde9-4c27-866e-966c3fba9fe1
Superblock backups stored on blocks: 
32768, 98304, 163840, 229376

Allocating group tables: 0/8   done                            
Writing inode tables: 0/8   done                            
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: 0/8   done

/dev/loop1 successfully formatted as ext4 (label "xbootldr", uuid 5dc11ee2-fde9-4c27-866e-966c3fba9fe1)
Successfully formatted future partition 1.
Populating ext4 filesystem.
Successfully populated ext4 filesystem.
Syncing future partition 1 contents to disk.
Formatting future partition 2.
ERROR: --compression must be used with --rootdir
btrfs-progs v6.17
See https://btrfs.readthedocs.io for more information.

(mkfs) failed with exit status 1.

[cdown]

Thanks, this is clearly quite broken. #39597 to straighten things out.