This is a series of commits which adds a feature needed by GNOME OS'
installer. This was show during All Systems Go 2025 talk:
https://cfp.all-systems-go.io/all-systems-go-2025/talk/QRJVL3/
To sum up this PR, this changes first systemd-repart to use BLKPG
partition instead of loop devices when possible. We need then to always
rescan the partitions to try remove partitions if it failed. We allow
encrypted partitions to stay activated and with a chosen name. And we
add a new partition configuration `BtrfsReplace=`.
Note that "replace" comes from the command `btrfs replace`. But in the
case of systemd-repart, maybe "inplace" or "move" would make more sense.
I open to suggestions.
If it is better I can split this into several PRs.
The commits:
## repart: Reuse the backing fd for fdisk
Because fdisk_assign_device tries to open block devices with O_EXCL,
when it does it blocks cryptsetup from using partition block devices for
the same disk.
Since we already have a file descriptor for the device, we can just
share it and use fdisk_assign_device_by_fd instead.
## repart: Use blkpg partitions instead of loop devices when possible
We will want to allow future features to keep some devices mounted or
active. So in order to avoid leaving a mess of many loop devices, we can
just already use the partition block device already.
## repart: Rescan disk on failure if we create blkpg partitions on the
fly
Since we did not write the partition table, then the created partitions
should get removed on error.
## repart: Allow keeping luks2 volumes opened
## repart: Add BtrfsReplace=
BtrfsReplace=/mntpnt will move the btrfs filesystem from mount point to
the partition created. After moving, it will resize to take the whole
partition.
This is useful for OS installers that move a live system into a disk and
do not require a reboot.
## repart: Add VolumeName=
When a luks2 device mapper is to be kept alive after execution of
systemd-cryptsetup, the name of the volume will be taken from this
value.
## test: Add test for repart's BtrfsReplace
$PATH might point to a systemd checkout containing
a newer version of systemd-journal-remote which we
should use, hence prefer an executable from $PATH
over the one from /usr/lib/systemd.
Even after switching the wait loop to a polling `journalctl --grep`, the
test still fails intermittently because the very first messages emitted by
the freshly-spawned systemd-networkd-wait-online process can carry stale
journald metadata. journald associates `_SYSTEMD_UNIT=` (and friends) with
each entry by reading `/proc/$pid/cgroup` of the originating PID; if those
messages are produced before journald notices the cgroup migration into the
new service, they get tagged with `_SYSTEMD_UNIT=init.scope`. The
`-u $unit` filter then fails to match them.
Capture a journal cursor before launching the unit, and grep using
`--after-cursor=` plus `SYSLOG_IDENTIFIER=systemd-networkd-wait-online`
instead of `-u $unit`. SYSLOG_IDENTIFIER is set by the program itself, so
it's not subject to the cgroup-discovery race. The cursor bounds the search
to entries produced by this invocation, so prior wait-online runs in
earlier testcases don't interfere.
Logs from the failing run showing the messages exist but are tagged with
the wrong unit:
[ 2570.948554] TEST-75-RESOLVED.sh[2178]: + unit=wait-online-dns-ede81407-b93b-459d-8e5d-69292b42d2ae.service
[ 2571.023162] TEST-75-RESOLVED.sh[2178]: + systemd-run -u wait-online-dns-ede81407-b93b-459d-8e5d-69292b42d2ae.service ...
[ 2571.049189] TEST-75-RESOLVED.sh[2178]: + timeout 30 bash -c 'until journalctl -b -u wait-online-dns-ede81407-b93b-459d-8e5d-69292b42d2ae.service --grep ...'
[ 2571.964986] systemd-networkd-wait-online[2190]: dns0: No DNS server is accessible.
[ 2601.051088] TEST-75-RESOLVED.sh[2178]: ++ cleanup
And for that 2571.964986 entry:
_SYSTEMD_CGROUP=/init.scope
_SYSTEMD_UNIT=init.scope
_EXE=/usr/lib/systemd/systemd-executor
_CMDLINE=/usr/lib/systemd/systemd-executor --deserialize 68 ...
SYSLOG_IDENTIFIER=systemd-networkd-wait-online
MESSAGE=dns0: No DNS server is accessible.
Follow-up for d4bc62713e
Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
When an LSM (e.g. SELinux) denies an fd transfer or the receiver hits
RLIMIT_NOFILE, the kernel drops the fd(s) from the SCM_RIGHTS cmsg and
sets MSG_CTRUNC on the recvmsg(). recvmsg_safe() turns that into
-ECHRNG, which causes json_stream_read() to discard the data bytes
that were nevertheless received and the varlink server to silently
tear down the connection — leaving the caller waiting for a reply
that never comes.
Inline the recvmsg() call instead and, on MSG_CTRUNC, drop the partial
fds but keep the message data. The method handler will surface a clean
-ENXIO when it tries to peek the missing fd, which sd-varlink wraps as
io.systemd.System for the peer, instead of a hang. This matches the
recent sd-bus fix in 6c8de404c9 ('sd-bus: allow receiving messages with
MSG_CTRUNC set').
BlockDeviceReplace=/mntpnt will move the btrfs filesystem from mount point to
the partition created. After moving, it will resize to take the whole
partition.
This is useful for OS installers that move a live system into a disk and
do not require a reboot.
We will want to allow future features to keep some devices mounted or
active. So in order to avoid leaving a mess of many loop devices, we can
just already use the partition block device already.
Because fdisk_assign_device tries to open block devices with O_EXCL, when it
does it blocks cryptsetup from using partition block devices for the same
disk.
Since we already have a file descriptor for the device, we can just share it
and use fdisk_assign_device_by_fd instead.
This requires at least libfdisk 2.35 (part of util-linux) which was
released in 2020.
If a unit has active jobs, when it gets serialized there are job
subsections, each with their own empty line marker. The skipping
function ignores this and skips until the marker, but then leaves
the job in place, breaking deserialization.
Consume jobs subsections too.
This shows up now that there's TEST-07-PID1.alias-corruption,
which occasionally fails when the aliased unit happens to
still have a job when the reexec happens.
```
[ 967.551630] TEST-07-PID1.sh[179]: + echo 'Testing with: systemctl daemon-reexec'
[ 967.551630] TEST-07-PID1.sh[179]: Testing with: systemctl daemon-reexec
[ 968.405274] TEST-07-PID1.sh[179]: + echo '--- Attempt 1/3 ---'
[ 968.405274] TEST-07-PID1.sh[179]: --- Attempt 1/3 ---
[ 968.698641] TEST-07-PID1.sh[179]: + echo 'Running daemon-reexec...'
[ 968.698641] TEST-07-PID1.sh[179]: Running daemon-reexec...
[ 969.130261] TEST-07-PID1.sh[179]: + echo 'legit.service PID remains 1282. Attempt 1 passed.'
[ 969.130261] TEST-07-PID1.sh[179]: legit.service PID remains 1282. Attempt 1 passed.
[ 970.870456] TEST-07-PID1.sh[179]: + echo '--- Attempt 2/3 ---'
[ 970.870456] TEST-07-PID1.sh[179]: --- Attempt 2/3 ---
[ 971.267205] TEST-07-PID1.sh[179]: + echo 'Running daemon-reexec...'
[ 971.267205] TEST-07-PID1.sh[179]: Running daemon-reexec...
[ 971.715743] TEST-07-PID1.sh[179]: + echo 'legit.service PID changed from 1282 to 1643!'
[ 971.715743] TEST-07-PID1.sh[179]: legit.service PID changed from 1282 to 1643!
```
https://github.com/systemd/systemd/actions/runs/25376867873/job/74414201255
Without CAP_SYS_ADMIN, btrfs_ioctl_snap_destroy() runs an
inode_permission(MAY_WRITE) check against the target subvolume root, which
btrfs_permission() rejects with EROFS for a read-only subvolume. As a
result, unprivileged removal of a read-only subvolume fails — both via
btrfs_subvol_remove_at() directly and via the recursive cleanup path used
by rm_rf_subvolume_and_freep(), which propagates the EROFS up.
Detect EROFS after the destroy ioctl, clear the RDONLY flag (only inode
ownership is required for BTRFS_IOC_SUBVOL_SETFLAGS), and retry once.
While at it, fix the surrounding comments: BTRFS_IOC_SNAP_DESTROY drops the
entire subvolume tree, so regular files inside are irrelevant; ENOTEMPTY
from the ioctl indicates nested subvolumes (BTRFS_ROOT_REF_KEY entries) via
may_destroy_subvol(), not non-empty contents.
The help string for --smart-relinquish-var and --relinquish-var
were in reversed order because of the _fallthrough_.
We would resolve the conditions for "smart relinquish" immediately
in parse_argv() and call 'return 0' if the conditions were wrong,
terminating option parsing and the program. It seems nicer to delay
action until later. This makes the logic flow more standard. This
also allows the option parsing cases to be exchanged, fixing the
issue with --help.
Two namespaces are used: "journalctl" and "journalctl-varlink". Help for
--user/--system in the latter is added, even though it is not used yet.
I think it'll be good to have this for introspection.
The four FSS-related options (--interval, --verify-key, --force,
--setup-keys) unfortunately each gain an inline #if HAVE_GCRYPT / #else;
the EOPNOTSUPP fallback is duplicated four times.
The metavar for --identifier/--exclude-identifier is changed to "ID"
to make the layout nicer. (And because that seems to make more sense.)
Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
We have different help strings for --user/--system in different places, so this
only covers a subset of --system/--user instances. But this particular help
seems to be the most widely used.
(In a few cases, the help string is fixed: it should be "system mode", not
"per-system mode".)
Pure reordering. ARG_SMART_RELINQUISH_VAR is kept immediately before
ARG_RELINQUISH_VAR because of the existing _fallthrough_; that's the
only deviation from strict --help order.
Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
Note, previously we replaced the previous option with the same option code with
new one. But, DHCP message can have multiple options with same option code.
Hence, this make the conf parser not replace, but append new one.
There are four DHCP options with confusing names:
Option 43: Vendor-Specific Information
Option 60: Vendor Class Identifier
Option 124: Vendor-Identifying Vendor Class
Option 125: Vendor-Identifying Vendor-Specific Information
Let's use their full names for their corresponding enums.
Yu Watanabe
Daan De Meyer
Luca Boccassi
Lennart Poettering
Valentin David
Bone NI
Zbigniew Jędrzejewski-Szmek
drhydroxide
hschloss