UpdateHomeEx needs to set up the home temporarily so that it can
write the refreshed identity records. Inspect and password changes use
the same setup path for metadata-oriented work.
For LUKS homes with luksDiscard=no, home_setup_luks() fully
allocates the backing image while setting it up. If diskSize=max was
previously written to a sparse image, this can fail with ENOSPC before
the user can disable auto-resize mode again.
Add a setup flag that lets metadata operations skip the full-image
fallocate step. Real create, activate, and resize paths keep the
existing allocation behavior.
Before, reproduced on Ubuntu 26.04 with /home on tmpfs:
homectl create reprohomed \
--storage=luks \
--fs-type=btrfs \
--disk-size=300M \
--auto-resize-mode=shrink-and-grow \
--luks-discard=no
homectl update reprohomed --disk-size=max
dd if=/dev/zero of=/var/tmp/homed-repro/filler bs=1M count=500
systemctl restart systemd-homed.service
homectl update reprohomed --auto-resize-mode=off
Operation on home reprohomed failed:
Not enough disk space for home reprohomed
Fixes#34527
Follow-up for: ab3b6fcb40
dongshengyuan
2ff5250ae7