Security review of 912f7c1: the mkfs wrapper trusts no sibling claim; the internal-place helper fails closed

- felhom-mkfs-guarded: the 0.158.0 exemption for a sibling part mounted at /mnt/<name> + under /mnt/felhom-drives is
  removed — the agent can make that corroborating mount itself. Every mount of every node outside /mnt/felhom-drives
  refuses (kernel mount table); an unlistable disk refuses. CandidatePartition.Formattable is false for every part of a
  disk with a mounted node, so it is never offered for formatting (attach still is).
- felhom-internal-place: a failed lvs listing, a listing without the pool, or a blkid exit other than 0/2 refuses
  (they read as "nothing promised" / "no signature" before).
Every new test was seen failing against the 0.158.0 versions.

Claude-Session: https://claude.ai/code/session_012qRErfCoiTkvDK9N5XHbzb

.claude/rules/unprompted-work.md

@@ -44,8 +44,12 @@ it **first** in the morning note. A decision you cannot write in that shape is o
    Throwaway apps only; the standing apps and `bentopdf` stay.
 5. **Evidence off the machine at the end of each phase**, before any revert (R-320).
 6. **One release per repo per session**, with a CHANGELOG entry (controller: with its `MinAgent`
-   line), REPORT overwritten, floor raised to deliver it. **No golden unless a drill or fresh install
-   needs one** (the waiver, R-468). **No `--no-verify`.**
+   line) and REPORT overwritten. **A controller release needs no golden** (operator ruling 2026-10-15
+   11:26, `09` §3 decision 250; decision 7 stands): push the image only when it is ready for EVERY box (the
+   household's update button offers the highest tag); raise the floor, MinAgent declared, only after it ran
+   on Tester 1, demo-hp and demo-felhom through the normal update path and the box walk's checks are green
+   on all three — not at night unless the night brief says so. **Agent releases still stop for the
+   operator's vouch.** The golden is baked weekly and vouched by the operator; CC never vouches. **No `--no-verify`.**
 7. **An enumerated gap becomes a row in the same session — or, if it is small, is fixed in it** (the size rule).
    Prose is not a record.
 8. **Hungarian text is searched with ASCII fragments**, with a positive and a negative control.
@@ -73,3 +77,19 @@ that no longer exists. Each edit is named in the report (file, line, before, aft
 operator's word: loosen a safety rule, a fence, a „never", a protected machine, a secret rule, or a review step; or
 remove a rule. When in doubt, it is a rule change, and it goes to the operator. If Claude Code's own permission check
 asks before such an edit, wait for the operator's click; if it refuses, record that and file the exact line.
+
+## 6. The system poster stays true
+
+**A session that changes a fact listed in `architecture/felhom-system-poster.facts.md` (a machine, a
+role, a traffic path, a backup tier, a time, a retention, a key, a known gap) updates that file in
+the same commit.** If the change is text only, it also edits the matching text in
+`felhom-system-poster.html`. If it needs a new drawing, it adds the line
+**"System poster needs a refresh: <what changed>"** to `STATUS.md`'s "waiting on the operator" list.
+**The session report names which of the three it did.**
+
+Why the three-way split: the poster is a drawing made in Claude Design, and **nothing in this
+repository renders it** — unlike `where-felhom-stands.html`, which has `render_stands.py`. So the
+facts file is the source of truth and the drawing trails it. `scripts/poster_facts_gate.py` warns
+when the facts file has a newer commit than the poster; it **never fails a push**, because a refresh
+needs the operator and another tool, and a gate nobody can clear is a gate people learn to route
+around.

CHANGELOG.md

@@ -1,4 +1,267 @@
-## Unreleased (2026-10-07) — the agent can no longer hand the guest any image; felhom-op's pct lines are exact (R-861 (a) A1, (b) B2; `09` §3 decision 165)
+## v0.158.0 — the internal data place; partitions as places; add_internal_place (2026-10-16)
+
+Design: felhom.eu `architecture/16-storage-physical-identity.md` §5, §6, §7, §9 (operator rulings D3–D5; the D3 sizes
+ruled 2026-10-16 after the space check, felhom.eu `audits/storage-identity-buildB-2026-10-15/SPACE-CHECK.md`).
+
+- **The internal data place („Belső tárhely")** (`internal/localapi/internalplace.go`): when the record
+  `/var/lib/felhom-agent/internal-place.json` names a filesystem, the agent mounts it at `/mnt/belso` by fs-UUID like an
+  enrolled drive (startup + every 20 s tick) and records it `enrolled`; `GET /disks` reports it with kind `internal`.
+  It never takes `/mnt/belso` from a household drive, and eject/decommission/format of it are refused (device-mapper on
+  the system disk). Its identity is the system disk's, so build A never counts a copy to `sys_drive` as a second copy.
+- **Root helper `configs/felhom-internal-place`** (new in the bundle): `plan|create <planned GiB>` — the ruled size rule
+  (reserve max(16 GiB, 10 %) ≤ 48 GiB, made only when ≥ 20 GiB, nothing promised beyond pool − reserve), the only
+  lvcreate/mkfs of a system-disk volume; formats only a `felhom-belso` with no signature. Run by the installer (1.33.0)
+  and by the new signed op.
+- **Signed op `add_internal_place`** (old one-disk boxes, `16` §9): no parameters (the size is the rule's), destructive
+  class (operator key). Runs the helper with `create 0`, writes the record, mounts.
+- **Partitions as places** (`internal/storage/partitions.go`): `GET /disks/candidates` lists each partition of a free
+  disk as empty / filesystem / in_use. A data-bearing part's wipe id binds disk id + part number + fs-UUID
+  (`byid:<…-partN>+fsuuid:<uuid>`); both must name the same device at format time.
+- **`felhom-mkfs-guarded`**: a SIBLING part that is Felhom's own drive (mounted raw at /mnt/<name> AND under
+  /mnt/felhom-drives) no longer blocks formatting the free part next to it; every other mount still refuses; an
+  unlistable disk now refuses (it passed before). First tests of the wrapper: `configs/test_felhom_mkfs_guarded.py`.
+- `configs/` changed (sudoers `FELHOM_INTERNALPLACE`, the helper, the wrapper, the bundle list) — **a config-bundle job
+  is needed** with the agent update. **Not vouched** (the operator's act).
+- Released: tag `v0.158.0` (code `912f7c1`), sha256 `a3589d1d…2caba`, bundle `17066273…fb5c76`.
+
+## v0.157.0 — every storage place knows its physical disk(s); POST /disks/same-disk (2026-10-15)
+
+Design: felhom.eu `architecture/16-storage-physical-identity.md` §3, §4, §10 (operator rulings D1–D6, 2026-10-15). Spike:
+felhom.eu `audits/storage-identity-2026-10-15/`.
+
+- **Identity of a storage place** (`internal/storage/identity.go`): the physical disk(s) under it, from `/sys`, `/run/udev/data`
+  and `/proc/mounts` only — partition → disk, device-mapper / LVM thin → slaves, loop → backing file → its disk. Keys:
+  `eui:` (NVMe), `serial:<bus>:<model>:<serial>`, `wwn:` only without a serial and only with a vendor (OUI ≠ 000000).
+  `proven`, or `unknown` with one reason: `vm` (systemd-detect-virt), `network`, `usb_bridge` (a placeholder serial — the rule
+  is the design's, UNPROVEN on a real enclosure, R-1077), `weak_wwn`, `no_serial`. No block I/O.
+- **Reported:** `GET /disks` rows and the hub report's `storage_targets` gain `kind`, `physical_disks`, `identity`,
+  `identity_reason` (additive; the golden and the hub's copy change together). A dir storage is judged only on its OWN mount — an
+  absent drive is "not computed", never the root disk.
+- **`POST /disks/same-disk`** `{a, b}` (guest paths) → `{different, proven, reason, a, b}`. Maps `/mnt/felhom-drives/<name>` to
+  the host mount at exactly that path, and `/mnt/sys_drive`, `/var/lib/felhom`, `/var/lib/docker` to the guest's data volume's
+  storage. Anything else, or an absent drive → `unmapped`. A shared disk key is "same, proven" even when the disk is unknown.
+  Scoped like every `/disks` call.
+- Tests: fixture `/sys` + udev trees for every spike case (one disk LVM thin, two disks, two partitions, a loop on a file, NVMe eui,
+  vendor-less WWN, a VM, a USB placeholder serial, a network share) and the same-disk call (equal, different, VM, NAS, absent
+  drive, scope); red-proofed (the LVM "diamond" bug was seen failing first; the VM, WWN, own-mount and sys_drive rules broken on purpose).
+- `configs/` unchanged — no config-bundle job needed. **Not vouched** (the operator's act).
+
+## Unreleased (2026-10-15, afternoon) — the shared rule file; no code change
+
+- `.claude/rules/unprompted-work.md` §3 item 6: **a controller release needs no golden** — the floor carries it after the
+  three test boxes; agent releases still wait for the operator's vouch; the golden is weekly (operator ruling 2026-10-15
+  11:26, `09` §3 decision 250; the same morning's „bake first", decision 247, reversed). Same text in all five copies.
+
+## Unreleased (2026-10-15) — the shared rule file; no code change
+
+- `.claude/rules/unprompted-work.md` §3 item 6: **bake first** — a controller release is released only when its golden is
+  baked; bake → the operator vouches → the operator raises the floor; never ask for a floor for a version with no golden
+  (operator ruling 2026-10-15, `09` §3 decision 247, superseding decision 7). Same text in all five copies.
+
+## v0.156.1 — R-1008 by process liveness, not the clock; 0.156.0 superseded — do not vouch it (2026-10-14)
+
+Released by `scripts/release-agent.sh`: binary sha256 `83c7da27d457b63ba8a4cde5a8717b3e5f9db9f83a46e63f38902dc7471bffb9`, bundle
+`5a678def792c70ec1cbbd198c14542161fac91d11a69bd0ce23dd86469e96ec3` (tag `v0.156.1` = `7ae3081`). Step bundle `0.156.1-step1`
+sha256 `ac83ea41507616d4c1056cccfd35de1410ff01e0296f4e64ff925207a43a8490` (the 0.155.0 bundle with only `felhom-os-apply`
+replaced), published as package version `0.156.1-step1`. **Not vouched** (the operator's act). Delivery as 0.156.0: per box
+`agent_update 0.156.1` → `agent_config_update 0.156.1-step1` → `agent_config_update 0.156.1`.
+
+- **0.156.0 is superseded — never vouch it.** A background security review of the pushed commit flagged „fail-open state
+  drift": 0.156.0 called a listed vzdump task dead when its wall-clock start was before the kernel's `btime`. `btime` is
+  derived from the wall clock and moves when the clock is corrected after the boot (an NTP step after a power cut), so a
+  backup started between the boot and the correction could look „from before the boot" — and the stale-lock pass would
+  clear a LIVE backup's lock.
+- **Now:** `taskAlive` is Proxmox's own rule (`PVE::ProcFSTools::check_process_running`, read on demo-hp): the UPID's pid and
+  pstart against `/proc/<pid>/stat` — same start tick (field 22) and not a zombie. No clock is involved. Fails safe (running)
+  when the UPID does not parse, the stat cannot be read, or this agent cannot see root's processes at all (PID 1 not visible:
+  a `hidepid` /proc or `ProtectProc=` would hide every worker — demo-hp: `/proc` plain, `ProtectProc=default`).
+- Tests: worker gone, pid reused, zombie, live worker, a „clock step" (wall-clock start absurdly early, worker alive → still
+  running), doubt, hidden /proc — each red-proofed; 19 guards in all (`power-cut-fixes-2026-10-14/redproof.txt`).
+- R-1006 (the cleanup) is unchanged; its „before this boot" rule still reads `btime`, but a drifted `btime` cannot remove a
+  live partial: the Go side asks this liveness rule, and the root helper refuses while any vzdump runs or anything holds
+  the file open.
+
+## v0.156.0 — after a power cut: the dead half-written backup is removed (R-1006); a backup task from before the boot is not „in flight" (R-1008) (2026-10-14)
+
+Released by `scripts/release-agent.sh`: binary sha256 `8db2278838dcb733d5201fba84b75a829b9adebdf899c89dd7de0939ec10d51a`, bundle
+`a21605217966ebc953d55a35157a9eb0243ca542c50dbd94fc9fa67257f27369` (tag `v0.156.0` = `a2f3aee`). Step bundle `0.156.0-step1` sha256
+`8be2bb8f3d54bff8e7140cf99714664df31adecf13aa721597323fb2b9d43db5` (the 0.155.0 bundle `795f2ab4…` with only `felhom-os-apply`
+replaced; `scripts/build-step-bundle.py`), published as package version `0.156.0-step1`. **Not vouched** (the operator's act).
+
+**Delivery: the agent binary AND the config bundle, and the bundle ADDS a path** (`/usr/local/sbin/felhom-vzdump-partial-clean`)
+— so per box: signed `agent_update 0.156.0` → `agent_config_update 0.156.0-step1` (the step bundle) → `agent_config_update
+0.156.0`. Evidence: felhom.eu `documentation/audits/power-cut-fixes-2026-10-14/` (the spike C1–C4, the red-proofs).
+
+- **R-1008 — one in-flight answer.** `staleLockController.BackupRunning` (the ONE implementation all four callers reach:
+  the start-up stale-lock pass, the guest-power watchdog, the household power-off guard, the controller supervisor) now
+  answers through `vzdumpInFlight`: a vzdump task for the vmid that started at or after the host's boot. Proxmox keeps a
+  dead task in `tasks?source=active` for ~30–60 s after a power cut (measured, C3) — the agent starts inside that window
+  and called it „genuinely in-flight". A task from before the boot is dead; logged once (vmid, UPID, start, boot). The
+  start time comes from the list or, if absent, the UPID; an unreadable boot time or start time FAILS SAFE (running), as
+  before. The boot time is `poweroff.ProcBtime` (no third /proc/stat parser).
+- **R-1006 — the half-written backup is removed.** New `internal/vzpartial`: on a `dir` backup target it finds exactly
+  `vzdump-(lxc|qemu)-<vmid>-YYYY_MM_DD-HH_MM_SS.(tar.dat|vma.dat|tmp)` of THAT guest (never a finished archive, a log,
+  another guest, a symlink, a wrong kind), and — only when no vzdump of the guest is in flight (R-1008) and the entry is
+  dead (modified before this boot, or untouched for 120 s) — asks the root helper to remove it. Runs at agent start (after
+  the stale-lock pass, every owned guest × every backup tier) and before every backup's space preflight
+  (`BackupRunner.SetBeforeBackup`). Any doubt leaves the entry and logs why.
+- **The root helper `configs/felhom-vzdump-partial-clean`** (config bundle; sudoers `FELHOM_VZPARTIAL`, one exact line: a
+  storage id, a vmid, one half-written name) re-checks everything as root: a `dir` storage from `/etc/pve/storage.cfg`; the
+  name of that vmid; not a symlink; directly in `<path>/dump`; **no vzdump on the host at all** (a job for several guests
+  carries no vmid in its task name); **no process holds the entry open** (C2: after a killed worker, `tar` and `zstd` kept
+  writing into the `.tar.dat` for 4 min 40 s, none named „vzdump"); dead (before this boot, or quiet 120 s).
+- **Not changed, by evidence (C4):** the space preflight's sizing (R-1006 part 2) — on „No space left" vzdump removes its
+  own partial on both its paths (rsync and tar); only a power cut leaves one.
+- **Tests:** `stalelock_inflight_test.go` (the helper, the production controller, three callers end to end, a structural
+  pin that every `BackupRunning` call goes through `s.staleLock` and there is one implementation), `vzpartial_test.go`
+  (removes; keeps in flight / unknown / non-dir / other names / recent / wrong kind / symlink / a helper refusal — each keep
+  with its positive control), `r685_space_test.go` (the cleanup runs BEFORE the preflight), the helper's own 21 Python
+  tests (`configs/test_felhom_vzdump_partial_clean.py`, run by the Go suite), 8 sudoers injection cases. **17 guards
+  red-proofed** by mutation (`power-cut-fixes-2026-10-14/redproof.txt`).
+- **Fixed without a row:** `internal/localapi/guestbind.go` and `controllersupervisor_test.go` were not gofmt-clean on
+  `main` (an import order and a struct alignment) — formatted.
+
+## v0.155.0 — the household can turn the machine off: POST /host/poweroff (R-998); the escrow reply race fixed (2026-10-13)
+
+Released by `scripts/release-agent.sh`: binary sha256 `bb339e944eff4aa6d10ae09158e0943de2e5c3777f52bf993c796d57e46800c3`, bundle
+`795f2ab41661e993e3fc4ce65df4f11ce94280d94871ab2e5cf1993ae3fbff7d` (tag `v0.155.0`). **Not vouched** (the operator's act).
+**The bundle changes `felhom-agent.sudoers`** (no new path — no step bundle): delivery is a signed `agent_update` +
+`agent_config_update`. Design: felhom.eu `documentation/architecture/14-host-power-off.md`.
+
+- **`POST /host/poweroff`** (local API, `withGuest`-scoped like `/guest/reboot`) — the controller's „A gép kikapcsolása"
+  (controller v0.310.0). Refused (409, a stable `reason`) in the first 10 min after boot; a second time in one boot
+  (`internal/poweroff`, a file keyed by `/proc/stat` btime); while ANY other guest or VM runs on the host (read from
+  `/proc`: `lxc-start -n N`, `kvm -id N` — demo-hp's scratch guest and Tester 1 VM block it); while the heavy-operation
+  gate is held (backup, restore test, OS step, sweep, trim), a backup job, a controller swap, a drive format, a NAS verify
+  or an escrow ceremony runs, or Proxmox runs a vzdump of the guest. Every check fails closed.
+- On acceptance: the record first; the heavy gate TAKEN and kept; a host report carrying `deliberate_off.requested_at`
+  accepted by the hub (bounded 60 s, `Loop.SetReportedHook`); then before each step the jobs and other guests are
+  checked again — a job waits (≤ 15 min), another guest cancels at once, a job still running after the wait cancels
+  (gate released, box stays on); `pct shutdown <vmid> --timeout 120`; `systemctl poweroff`.
+- **Sudoers:** `FELHOM_POWEROFF` = `/usr/bin/systemctl poweroff`; `pct ^shutdown [0-9]+ --timeout [0-9]+$` joins
+  `FELHOM_GUESTHOOK`; nine injection cases (`--forceStop`, `poweroff --force`, `reboot`, `halt`, `kexec`…).
+  **New `TestEveryAliasIsGranted`:** an alias missing from the grant line passed the coverage check before.
+- **Host report:** `deliberate_off` (omitempty; the cross-repo golden unchanged). Hub v0.149.0 holds its silence alarms
+  for 14 days on it.
+- **Fixed without a row:** `go test -race` found a data race in the escrow ceremony start reply (it read `job.Phase`
+  while the job goroutine wrote it); the reply fields are copied first. Red before, green 3/3 after.
+- Security review (three passes the same evening): other guests, a gate not held, fail-open unwired checks, jobs and
+  guests starting after acceptance — each fixed and red-proofed (`hostpoweroff_test.go`, 11 tests).
+
+## v0.154.0 — no OS leg after a household press; the after-boot kernel report carries the real ring (R-899); no „wrong code" when older packages were not checked (R-304); the last backup survives a restart in the host report; the Secure Boot meta-package leaves the Proxmox lane (2026-10-09)
+
+Released by `scripts/release-agent.sh`: binary sha256 `36a54ad20e896cd61d7b9944e2a521f4209c2b76940d8f1827af05b645463226`, bundle
+`93487989f50d4a3039a05cec0f91ec478d62489a414705e49403e9b1340d20e0` (tag `v0.154.0` = `db25b46`).
+
+**Delivery: the agent binary AND the config bundle** — the wrapper `felhom-os-apply` changed (2026-10-09).
+
+- **The hub's backup evidence survives a restart (2026-10-09, found in the kernel-night read-back).** The host report's
+  `backups` list came only from memory, which is empty after an agent restart. On demo-felhom the night backup landed
+  02:40 UTC and the kernel step restarted the host at 02:44 — no report fell in between, two nights running — so the hub
+  alarmed „host tier: newest backup is 48h old" at 03:00 after a good backup. The report now adds R-894's saved newest
+  success per tier and guest (`backup-success-state.json`, ONE instance shared with the local API) where memory holds no
+  success at or after it. Only successes are saved, so a failure is never hidden. `hub.KnownBackupReporter`,
+  `BackupSuccessState.KnownBackupSuccesses`; tests `TestCollectBackups_SavedSuccessSurvivesARestart` (red-proved: the
+  restart case reported nothing), `TestBackupSuccessState_KnownBackupSuccessesSurviveAReopen`, and
+  `TestR894_LastKnownBackupsIsWiredIntoTheDaemon` now also asserts the collector gets the same instance (red-proved).
+- **`proxmox-secure-boot-support` is a boot-chain package (2026-10-09).** On demo-hp (Secure Boot on) its upgrade pulled
+  `shim-signed-common`; in the ring-0 Proxmox plan that refused the whole step (R6) and skipped the night's kernel step,
+  after the household had been told „tonight". It joins `HOST_SLOW_RE` with shim and GRUB (they stay out of every lane,
+  as before). `test_ring0_pending_pve_leaves_the_secure_boot_meta_out` (red-proved).
+
+- **R-899 (operator ruling 2026-10-08, option A):** `POST /backup?trigger=manual` (a „Mentés most" press, sent by the
+  controller from its next release) runs no OS leg after it: the leg belongs to the night, after the night's own copy.
+  Before, a press ran the leg at once (in the day; on 2026-10-07 08:51 demo-hp skipped it only by the 20-hour rule). A
+  request without the parameter (an older controller, the scheduled path) behaves as before.
+  `internal/localapi/server.go`; `TestAfterPrimaryBackup` gained two sub-cases (red-proved: ignoring `trigger`, the leg
+  ran once after a press).
+- **R-304 — „wrong code" only when every earlier package was tried.** `POST /escrow/recover-offsite-password` answered
+  400 („the recovery code did not open the sealed bundle") whenever the current package and the TRIED earlier packages
+  refused the code — even when the hub withheld earlier packages (rows with no key material, rows over its serve cap), a
+  served package was malformed, the 6-attempt cap stopped the loop, or the retained list could not be read at all. Now
+  those cases answer **424** with `older_unchecked` (the count, -1 = unknown) and a sentence that does not call the code
+  wrong. `escrow.ErrRetainedUnchecked` / `RetainedUncheckedError`; the retained fetcher's second value is now every
+  withheld package (unopenable + truncated + malformed). Tests `TestR304_*` (real age crypto; red-proved: without the
+  check, four cases returned the wrong-code error) and a 424 row in `TestRecoverOffsitePassword_EachSituationGetsItsOwnStatus`.
+  An older controller maps the unknown 424 to its neutral „we do not know why" sentence.
+- **The „ring 1" label after a boot:** in the first second after a reboot the agent has not fetched the hub's block, and
+  the after-boot kernel reports (`judging`, `good`, `revert`, `fell_back`…) said ring 1 on a ring-0 box (demo-felhom,
+  2026-10-08 night). Now they read the fetched block, else the block the daemon saved on disk before the reboot (R-866),
+  else ring 1 as before. A label only — the hub's approval reads its own ring list. `kernelReportRing`,
+  `TestKernelReportRing_BeforeFirstFetch` (red-proved: ring 1, want 0).
+
+## v0.153.0 — ring 0 stages exactly the told kernel (R-898; `09` §3 decision 176) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `b204ebe6d65944f43b70dcfa4ae0dfb90da38c92e2ba6a38a1826e488eeb6630`, bundle
+`6db216275eb0dd39188d93481a2045998a69e8cb7838ad908a58d65d9a6a9b57` (tag `v0.153.0` = `2d1e5d0`). Delivered (binary only — the
+bundle files are unchanged from 0.152.0) to demo-hp, demo-felhom, Tester 1 on 2026-10-07 19:03.
+
+**Delivery: the agent binary only** — no root file changed (the wrapper is unchanged; its tests gained two cases).
+
+- `internal/osupdate/kernel.go`: ring 0's night kernel step stages EXACTLY the kernel the household was told about
+  (select `listed`, `KernelSet(kver)` = the series meta-package and the signed image at the kernel's own version) instead
+  of "whatever is pending tonight". Seen 2026-10-07: demo-felhom was told about 7.0.14-20 while its sources offered
+  7.0.14-22 by night — the old code staged `pending-kernel` and the wrapper refused it (R23), losing the night. A told
+  version that is no longer installable is refused by the wrapper before any change (R7) and the hub tells the household
+  again for the newer kernel (hub v0.143.1). Tests `TestKernel_Ring0ToldNightStagesThenReboots` (red-proved against the
+  old select), `TestKernelSet`; wrapper `test_ring0_listed_installs_the_told_kernel_not_the_newest`,
+  `test_ring0_told_kernel_gone_is_refused_before_any_change`.
+
+## v0.152.0 — the kernel lane (R-836; `09` §3 decisions 164, 172; `11` §5.11) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `95ff42208e36ba49b6e2b09a97e81a6fa11562ecc8042f1ed18d378b8b1f88b1`,
+config bundle sha256 `f0c2cec374b711b3c131c955012b33fd0ad495337d049b7a743c3eef9e85c20b` (tag `v0.152.0` = `d03ab7f`).
+Step bundle `0.152.0-step1` sha256 `0b71d32b054cf3b7ade0234ffcbb0df159901f542cde540adaee411db466f48e` (the 0.151.0 bundle
+with only `felhom-os-apply` replaced; `scripts/build-step-bundle.py`), published as package version `0.152.0-step1`.
+
+**Delivery: agent binary, then the STEP bundle `0.152.0-step1`, then the bundle `0.152.0`** — the bundle ADDS two paths
+(the GRUB generators), and an installed `felhom-os-apply` refuses a path its own table lacks (R16, R-880).
+
+A new kernel boots ONCE; if it crashes the box comes back on the old kernel by itself; it becomes the default only after
+a healthy boot; a booted-but-unhealthy kernel is reverted ONCE by the agent with no person. Built on the spike's
+candidate 2 (`audits/kernel-spike-2026-10-07/`), with option C on the one-shot entry.
+
+- `configs/felhom-grub-oneshot.sh` → `/etc/grub.d/01_felhom_oneshot` (bundle): reads `felhom_next` from a GRUB env block
+  on the ESP (`EFI/felhom/oneshot.env`), clears and saves it BEFORE the menu, and sets the default to that kernel's
+  one-shot entry only when the name is an installed kernel. No vfat ESP → prints nothing.
+- `configs/felhom-grub-oneshot-entries.sh` → `/etc/grub.d/42_felhom_oneshot` (bundle): one entry per installed kernel,
+  id `felhom-oneshot-<ver>`, the normal entry plus `softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10`
+  (option C). Sorted after `10_linux`: never entry 0, never the default.
+- `configs/felhom-os-apply`: layer `kernel` (lane slow; an appliance; authority = a signed `os_kernel_step` or the
+  root-owned ring-0 mark). Modes: `apply` STAGES (select `pending-kernel` or a signed `listed` set; `expect_kver` = the
+  kernel the household was told about): pins the GRUB default to the RUNNING kernel in
+  `/etc/default/grub.d/zz-felhom-kernel-default.cfg` and proves it from grub.cfg, installs, proves the default did not
+  move and the one-shot entry exists, writes the flag; never reboots. `kernel-reboot` (a staged step only),
+  `kernel-boot` (judging | fell_back | self_reverted | revert_failed), `kernel-good` (the new kernel becomes the
+  default, proved), `kernel-revert` (ONE per step; refused when the default is not the old kernel), `kernel-cancel`,
+  `kernel-status`. New refusals: R20 (the box cannot do a one-shot: not UEFI, no vfat ESP, a separate /boot, GRUB
+  without fat/loadenv, the generators missing, a hand pin), R21 (the crash guard tripped or an unclean boot in its
+  window), R22 (the phase does not allow the mode; never two steps within 20 h), R23 (not exactly one newer kernel, or
+  not the one signed / told). State `/var/lib/felhom-kernel/state.json`. Facts carry `kernel_lane`; the next-boot
+  kernel reads the flag and the grub.cfg default. Tests: `KernelLane` (27), red-proof
+  `felhom.eu/documentation/audits/kernel-lane-2026-10-07/A/redproof.txt`.
+- `configs/felhom-crash-guard` unchanged; `KernelStepCannotLeaveTheBoxOff` (3 tests) pins that a step's planned reboot,
+  one crash and one self-revert add ONE unclean boot (a panic before userspace adds none), so the box cannot stay off.
+- `internal/osupdate/kernel.go`: the night leg ends with the kernel step — after a healthy host step (and a healthy
+  Proxmox step when one ran), trigger `night` only, on a night the hub's `os_update.kernel` block marks `tonight` (the
+  household was mailed the day before — no mail, no step). Ring 0 stages + reboots; ring 1 reboots only a kernel a
+  signed `os_kernel_step` staged (`KernelStepExecutor`: stage only, under the heavy-op gate). The hub hears `staged`
+  BEFORE the reboot. At every start `KernelAfterBoot`: on the new kernel it JUDGES the boot — `KernelVerdict` = the
+  host health rule (`11` §8.2) AND the box reached the hub (the `judging` report itself) — for 20 minutes (measured:
+  everything healthy 68 s after the reboot on demo-felhom, 272 s on demo-hp; under the hub's 45-minute `host_stale` (`alerting.stale_threshold`)).
+  Healthy → `kernel-good`, outcome `applied`; not healthy → outcome `health_failed`, then ONE `kernel-revert`.
+  Tests: `TestKernel*` (13); red-proofs in the same file.
+- `internal/hub`: `WireOSUpdate.Kernel` {kver, tonight, notified_at}. `internal/reconcile`: `os_kernel_step` is
+  destructive-class. `cmd/felhom-opsign`: the op is listed.
+
+## v0.151.0 — the agent can no longer hand the guest any image; the Proxmox package lane; the other-key archives reported; the DR directive retired (R-861, R-812 A, R-366, R-105; `09` §3 163, 165, 168, 169) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `0464354f2cdf452a7c5d2a74d9191fe91415fcfa244154480d26d5b30e10b194`
+config bundle sha256 `bacd1d175a9392bc1755341d01a106abbd72aba48ab575e7a32dd819d8f5da4c` (tag `v0.151.0` = `dd7cdc0`).
+**Deliver the binary FIRST, then the bundle:** the bundle's sudoers removes the `tee` grant the 0.150.0 binary still uses.
+No path added (26 → 26), so no step bundle.
+
+### Part of v0.151.0 — the agent can no longer hand the guest any image; felhom-op's pct lines are exact (R-861 (a) A1, (b) B2; `09` §3 decision 165)
 
 **Delivery order: agent binary FIRST, then the config bundle.** The new sudoers drops the agent's in-guest `tee`
 grant; an older binary still calls `tee`, so a bundle that lands before the binary would stop managed controller
@@ -20,7 +283,7 @@ updates (and the old binary's capability probe would read `controllerswap-write`
   `TestSudoersAllowsTheControllerImageVerb`, `TestFelhomOpSudoersPctIsExact`, `TestR861_WriteControllerImageUsesTheRootVerb`,
   `TestControllerSwap_WriteViaRootVerb_NoShell`. Red-proofs: `felhom.eu/documentation/audits/day-2026-10-07/C/`.
 - `README.md`: the controller-swap paragraph described the removed `tee` path — corrected.
-## Unreleased (2026-10-07) — the Proxmox package lane (R-812 option A, `09` §3 decision 163)
+### Part of v0.151.0 — the Proxmox package lane (R-812 option A, `09` §3 decision 163)
 
 **MinAgent impact: none** (a new layer; an older hub ignores the pve report). **The bundle carries the new
 `felhom-os-apply` — deliver it with the binary** (signed `agent_update`, then signed `agent_config_update`).
@@ -29,7 +292,7 @@ updates (and the old binary's capability probe would read `controllerswap-write`
 - `internal/pvegate` (new): the agent's own writes to /etc/pve wait while a pve step runs (pmxcfs restarts); the step waits for writes in flight (bounded, 2 min — then it fails and does not run). Wired at `proxmox.Client.doBody` (every non-GET) and `ExecRunner.RunStdin` (`WritesEtcPVE`: pct config verbs, pvesm, pveum, felhom-pbs-apply create/reconcile).
 - `internal/osupdate`: `LayerPVE`; the night leg runs the pve step in ring 0 after a healthy host step (an appliance; ring 1 never in the night leg); `PVEHealthVerdict` = the host rule + every running container keeps its id + pveversion reads the installed pve-manager; the pve report carries Proxmox userspace only (the hub's candidate set). `PVEStepExecutor` (signed `os_pve_step`, ring 1, under the heavy-op gate and the /etc/pve gate); `reconcile.ClassOSPVEStep` (destructive-class); `felhom-opsign -op os_pve_step` (params by `-params`).
 - Tests: wrapper `PVELane` (17; red first — the `pve-manager` plan was refused R12 on the old code), `pvegate` (5), `TestPVEGate_*` + `TestWritesEtcPVE`, `TestPVE_*`, `TestPVEHealthVerdict`, `TestPVEStepExecutor_*`. Red-proofs: `felhom.eu/documentation/audits/day-2026-10-07/B/`.
-## Unreleased (2026-10-07)
+### Part of v0.151.0
 
 - R-366 slice 2 (`09` §3 decision 168): the restore-test pick records, per tier, the archives it skipped as written with another key (count, oldest, newest — no key material) in a `ForeignKeyLedger`; the host report carries it as `foreign_key_archives.tiers` (the stanza absent until a tier was evaluated since start, `tiers: []` when none — no null on the wire, the report contract forbids it). The hub turns a change into one operator line. Tests `TestR366_PickRecordsArchivesWrittenWithAnotherKey`, `TestR366_EvaluatedWithNoneIsAnEmptyList` (red-proved, `felhom.eu/documentation/audits/day-2026-10-07/E/`).
 - R-105 option A (`09` §3 decision 169): the `--selftest=escrow-create -directive <file>` flag and the escrow upload's `directive` field are removed — nothing read the directive; the DR path reads the recipe, tenantsync and the escrow blob. The hub ignores a `directive` from an older agent.

CONTEXT.md

@@ -1,5 +1,18 @@
 # CONTEXT — felhom-agent working state
 
+> **2026-10-15 (night) — v0.157.0 RELEASED, NOT VOUCHED (storage identity build A, felhom.eu `16` §13).** Every storage
+> place carries `kind`, `physical_disks`, `identity` (+ reason) in `GET /disks` and the hub report; `POST /disks/same-disk`
+> answers the controller (v0.317.0, MinAgent 0.157.0). Computed on every read, never cached. Delivered by signed jobs to
+> Tester 1, demo-hp, N100 only. Next: the operator vouches 0.157.0 → the global floor 0.317.0 / MinAgent 0.157.0. Build B
+> (partition candidates, the internal place) waits for a task file (R-1079).
+
+> **2026-10-08 (day) — UNRELEASED on main, ships with tomorrow's release (decision 178).** R-899: `POST /backup?trigger=manual`
+> runs no OS leg (`localapi/server.go`); after-boot kernel reports carry the saved block's ring (`kernelReportRing`). R-304:
+> `escrow.ErrRetainedUnchecked` → HTTP 424 `older_unchecked` when not every earlier package was tried (withheld, caps,
+> malformed, unreadable list). Binary-only delivery; no wrapper or root file changed.
+
+> **2026-10-07 (evening) — v0.152.0, the kernel lane (R-836, decision 172, `11` §5.11).** Wrapper layer `kernel` + two GRUB generators in the bundle (delivered with step bundle `0.152.0-step1` — the bundle adds paths, R-880); `osupdate/kernel.go`: night step on told nights only, after-boot judge (host rule + hub reached, 20 min), ONE self-revert, `os_kernel_step` stages only. Proven on Tester 1 (panic → fell_back, held guest → self_reverted, healthy → 7.0.14-22 default). Open: R-898, R-897; the ring-0 night run.
+
 > **2026-10-04 night — v0.143.0 RELEASED + vouched (R-840, decision 96): the config bundle.** `felhom-os-apply` mode
 > `bundle` (signed `agent_config_update`, verified by the wrapper itself; trust files never bundle paths) +
 > `--install-bundle` (installer 1.31.0); `BUNDLE_FILES` is the one table; `scripts/build-config-bundle.py`;

REPORT.md

@@ -1,8 +1,43 @@
-# REPORT — v0.150.0 released and delivered (2026-10-07)
+# REPORT — v0.157.0: every storage place knows its physical disk(s); POST /disks/same-disk (2026-10-15)
 
-On the operator's word (`09` §3 decision 161). `scripts/release-agent.sh 0.150.0`: sha `a23d1c90…`, bundle `88456b38…`,
-tag `v0.150.0` = `3a72a48`, verified by download. Vouched with golden 0.301.0 and MinAgent 0.131.0 (unchanged). No bundle
-path added (26 → 26), so no step bundle. Signed `agent_update` → demo-hp, demo-felhom, Tester 1 on 0.150.0 (07:06–07:07Z);
-signed `agent_config_update` → `BUNDLE DONE written=1 same=24 self-check=ok`, capability probe 68/68 on all three
-(07:21Z). Tester 2 not touched. Carries R-528 (the memory-kill check), R-894 (the last backup per tier on disk), R-330
-(SMART counters on the wire). Evidence: `felhom.eu/documentation/audits/readback-2026-10-07/delivery/`.
+Written in ASD-STE100 Simplified Technical English. Design read first: felhom.eu `architecture/16-storage-physical-identity.md`
+(§3, §4, §8, §10; ACCEPTED 2026-10-15, §13 = what was built), `03-host-agent.md`. Task: storage identity build A (operator
+rulings D1–D6). Controller counterpart: felhom-controller v0.317.0 (MinAgent 0.157.0); hub v0.154.0 shows the fields.
+
+## What changed
+
+- `internal/storage/identity.go`: the physical disk(s) under a place, from `/sys`, `/run/udev/data`, `/proc/mounts` only
+  (no block I/O). `proven`, or `unknown` with `vm` / `network` / `usb_bridge` / `weak_wwn` / `no_serial`.
+- `GET /disks` rows and the hub report's `storage_targets` gain `kind`, `physical_disks`, `identity`, `identity_reason`.
+- `POST /disks/same-disk` `{a, b}` → `{different, proven, reason, a, b}`; scoped like every `/disks` call; a path the agent
+  did not mount itself is `unmapped`.
+- `configs/` unchanged.
+
+## Tests and red-proofs
+
+Fixture `/sys` + udev trees for every spike case and five same-disk handler tests. Seen failing first: the LVM thin
+„diamond" (tmeta/tdata under one pool) read as a failure — fixed by counting a seen node once. Broken on purpose and seen
+failing: the VM rule, the vendor-less WWN rule, the own-mount rule (an absent drive), the `sys_drive` mapping.
+`python3 scripts/agent_gates.py`: all OK.
+
+## Release and delivery
+
+- `scripts/release-agent.sh 0.157.0`: tag `v0.157.0`, sha256 `addd4041…0aef`, bundle `0604bc60…397a`.
+- Delivered by signed `agent_update` jobs to Tester 1, demo-hp and the N100 (the three test boxes). **NOT VOUCHED** — the
+  operator's act. Until the vouch, the global floor cannot declare MinAgent 0.157.0.
+
+## Live proof (method: the agent's local API on each PVE host, with the guest's own token)
+
+| Box | `GET /disks` | same-disk: drive vs system data |
+|---|---|---|
+| demo-hp | `local`/`local-lvm` proven (SATA SSD), NVMe drive proven (`eui:`), PBS `network` | different, proven |
+| N100 | system proven (SATA SSD serial), USB drive proven (the bridge passes the real serial) | different, proven |
+| Tester 1 (VM) | every place `unknown/vm` | not proven (`vm`) |
+
+On all three: system data vs `/var/lib/docker` → same disk, proven; a drive name that is not mounted → `unmapped`. The hub
+stored the same fields (read from its database with the WAL). Evidence: felhom.eu `audits/storage-identity-buildA-2026-10-15/`.
+
+## Observations
+
+1. FILED: R-1083 — scratch box 9202 has no `local_api` in its `bootstrap.json`, so it cannot use any agent call.
+2. NOT-A-FINDING: `usb_bridge` is built from the design's rule and was not seen on a real enclosure; that is R-1077, already open.

REUSE.md

@@ -41,6 +41,11 @@
 | `storage.ResolveStorageDevice` | internal/storage/durable_device.go | `ResolveStorageDevice("uuid:<fs-uuid>") (dev, err)` | re-resolve enrolled STORAGE drives (remount) | `uuid:` scheme ONLY — distinct from the wipe schemes; never trust a remembered /dev node |
 | `deriveDurableID` | internal/storage/durableid.go | `deriveDurableID(typ, s, backingDevice, uuid) string` | storage-target durable id (DR re-attach key) | Deterministic per type; `uuid:` for usb/local-dir; PBS id includes `#<fingerprint>` |
 | `SystemDisks` / `isSystemBacked` / `RoleForStorage` / `RoleForRawDevice` | internal/storage/role.go | `RoleForRawDevice(device, sysDisks, sysKnown) DeviceRole` | protection-tier classification | Fails safe to `system` (most protected) on any ambiguity; role is AGENT-derived, never caller-supplied |
+| `storage.IdentityResolver` / `Relation` / `MountFor` | internal/storage/identity.go | `HostPath(path) PlaceIdentity`, `Device(dev) PlaceIdentity`, `Relation(a, b) (different, proven, reason)` | physical-disk identity of a storage place (felhom.eu `16-storage-physical-identity.md` §3, v0.157.0) | Reads /sys + /run/udev/data + /proc/mounts only (no block I/O). Judge a drive ONLY on its own mount (`localapi.ownMountIdentity`) — never the containing fs, or an absent drive reads as the root disk. A shared disk key is "same, proven" even when unknown. Pinned by identity_test.go (fixture trees) + samedisk_test.go |
+| `localapi.Server.EnsureInternalPlace` / `InternalPlaceRecord` | internal/localapi/internalplace.go | `EnsureInternalPlace(ctx)` (startup + 20 s tick); `ReadInternalPlace` / `WriteInternalPlace` | the one-disk box's internal data place (felhom.eu `16` §5, v0.158.0): mounts it at /mnt/belso by fs-UUID like an enrolled drive, records it `enrolled`; the controller binds + registers it | Never takes /mnt/belso from a household drive (a foreign mount, or a unit naming another UUID, waits). Never formats/ejects (dm on the system disk → role system). The ONLY maker is the root helper `configs/felhom-internal-place` (installer + signed `add_internal_place`). Pinned by internalplace_test.go |
+| `configs/felhom-internal-place` | configs/ (bundle → /usr/local/sbin) | `plan\|create <planned GiB>` | the ruled size rule (reserve max(16, 10 %) ≤ 48 GiB; ≥ 20 GiB or nothing) + the only lvcreate/mkfs of a system-disk volume | Formats only a felhom-belso with NO signature; refuses a foreign one; never resizes/removes. Sudoers: `^(plan\|create) 0$` only. Pinned by configs/test_felhom_internal_place.py |
+| `storage.candidatePartitions` / `CandidatePartition` | internal/storage/partitions.go | `CandidateDisk.Partitions` | partitions as places (`16` §6): empty / filesystem / in_use per part of a free disk; `Formattable` only while no node of the disk is mounted | A part with children or a member type is never listed; a raw /mnt mount counts as Felhom's only when corroborated (felhomOwnedMounts) — for LISTING only: the root mkfs wrapper trusts no such claim (v0.158.1). Pinned by partitions_test.go |
+| partition wipe id `byid:<…-partN>+fsuuid:<uuid>` | internal/storage/durable_device.go | `DeviceDurableID` / `ResolveDurableDevice` | a data-bearing PART binds disk id + part number + filesystem (`16` §6) | Both halves must resolve to the SAME device or the wipe refuses. Whole disks keep the plain id. Pinned by partition_durable_test.go |
 | `ValidateUUID/MountPath/BlockDevice/FSType/SMARTDevice/LVMName`, `UnitNameForMount` | internal/storage/validate.go | `Validate*(v) error` | EVERY arg that reaches a root shell-out | The security boundary; strict whitelists (no by-* symlinks, no dm, no traversal); `systemdEscapePath` computed in-process |
 | `ValidateNetworkMountSpec` | internal/storage/netmount.go | `ValidateNetworkMountSpec(spec) error` | NAS mount input boundary | Same discipline as validate.go; SMB requires a creds ref; mountpoint confined under `NetworkMountRoot` |
 
@@ -89,6 +94,7 @@
 | Symbol | File | Short signature | Use for | Gotchas |
 |---|---|---|---|---|
 | `pvegate.Write` / `pvegate.Step` | internal/pvegate/pvegate.go | `Write(ctx) (release, waited, err)` / `Step(ctx) (end, err)` | R-812 option A: keep the agent's own /etc/pve writes out of a Proxmox package step (pmxcfs restarts) | Already wired at the two chokepoints — `Client.doBody` (every non-GET) and `ExecRunner.RunStdin` (`WritesEtcPVE`: pct config verbs, pvesm, pveum, felhom-pbs-apply create/reconcile). A new root CLI that writes /etc/pve goes into `WritesEtcPVE`, never its own lock. Never take `Step` around anything but the wrapper call (`Leg.runPVE`) — a `Write` inside a `Step` deadlocks until its context ends. |
+| `osupdate.KernelVerdict` / `Leg.KernelAfterBoot` | internal/osupdate/kernel.go | `KernelVerdict(before, after, tunnel, hubReached) (ok, why)` | R-836: THE one-shot-boot rule — the host health rule (`HostHealthVerdict`) AND the box reached the hub since the boot | The only judge of a new kernel. Never reboot the host from Go: every reboot is the wrapper's (`kernel-reboot`, `kernel-revert`), and only for a staged step. A new kernel-lane state lives in the wrapper's `/var/lib/felhom-kernel/state.json`, never in the agent's own files (the agent can write those). |
 | `Client.WaitTask` | internal/proxmox/task.go | `WaitTask(ctx, upid, opts) (TaskStatus, error)` | asserting EVERY mutating op | POST 200 ≠ success; authz can fail at task exec; `AllowWarnings` opt-in |
 | `Client.Pool` | internal/proxmox/query.go | `Pool(ctx, name) (PoolInfo, error)` | felhom-pool membership (the ownership registry, A1) | Needs `Pool.Audit` at `/pool/<name>` (host-install v1.9.0+); `Pool.Allocate` does NOT satisfy the read; members can be storages (type `storage`, vmid 0) — filter them |
 | `Client` mutate wrappers (`RestoreLXC/Vzdump/DestroyLXC/Snapshot/Rollback/SetConfig/ResizeLXC/Start/Stop`) | internal/proxmox/mutate.go | return `(upid, error)` | all API mutations | Async → always pair with WaitTask; route via gate/queue, not ad-hoc |
@@ -157,6 +163,7 @@
 | `proxmox.Runner` | internal/proxmox/privileged.go | `*ExecRunner` (direct/sudo) | `mockRunner` internal/proxmox/mock_test.go; runner fakes in storage tests |
 | `storage.HostOps` | internal/storage/hostops.go | `*SudoHostOps` (prod), `NoopHostOps` (degraded) | fakes in internal/storage/observe_test.go, watchdog_test.go |
 | `storage.HostReader` | internal/storage/hostread.go | `*ProcHostReader` | `fakeHostReader` internal/localapi/disks_test.go; internal/storage/role_test.go. v0.87.0: `BlockSlaves(name)` lists `/sys/block/<name>/slaves` (root-free) — backs the `SystemDisks` dm/md walk (`physicalDisksOf`/`walkSlaves`, role.go); per-branch conservatism: an unresolvable slave fails the WHOLE walk → all-system fail-safe. NEVER weaken the signature test `TestSystemDisks_WalkTopologies` (root-backing disk always in the system set). |
+| `storage.IdentityHost` | internal/storage/identity.go | `*SysfsIdentityHost` | fixture /sys + udev trees in identity_test.go (`newFx`); `fakeIdentHost` in internal/localapi/samedisk_test.go. A SEPARATE interface from HostReader on purpose — adding methods to HostReader would break every existing fake. |
 | `localapi.DiskOps` / `StorageGate` / `GuestAttacher` / `GuestLister` | internal/localapi/disks.go | `*storage.SudoHostOps`; `storageGateAdapter` (cmd/felhom-agent/main.go); `*GuestBinder`; `*proxmox.Client` | `fakeDiskOps`/`fakeGate`/`fakeGuestAttacher`/`fakeGuestList` internal/localapi/disks_test.go |
 | `lanresolver.hostRoot` + `dnsmasqUnitPaths` (data seam, R-317) | internal/lanresolver/lanresolver.go | prod `hostRoot = "/"`; probe = the `dnsmasq` package's systemd UNIT, never `/usr/sbin/dnsmasq` (owned by `dnsmasq-base`) | internal/lanresolver/ensure_dnsmasq_test.go — fixture root tree + recording `proxmox.Runner`; the REAL `os.Stat` probe and `EnsureDnsmasq` run. `TestEnsureDnsmasq_ProductionProbeIsTheUnit` pins the production wiring |
 | `localapi.GuestAPI` / `BackupService` / `BackupStore` / `TokenAuthority` | internal/localapi/server.go | `*proxmox.Client`, `*backup.BackupRunner`, `*backup.Store`, `*TokenStore` | `fakeGuests`/`fakeBackups`/`fakeStore` internal/localapi/server_test.go |

cmd/felhom-agent/main.go

@@ -50,6 +50,7 @@ import (
 	"gitea.dooplex.hu/admin/felhom-agent/internal/pbs"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/pbsdr"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/poke"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/poweroff"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/provision"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
@@ -58,6 +59,7 @@ import (
 	"gitea.dooplex.hu/admin/felhom-agent/internal/selfupdate"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/vzpartial"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/wgtunnel"
 )
 
@@ -775,6 +777,7 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	hostReader := storage.NewProcHostReader()
 	hostOps := newHostOps(cfg, logger)
 	observer := storage.NewObserver(px, hostReader, hostOps, logger)
+	observer.SetIdentity(storage.NewIdentityResolver()) // `16` §3 physical-disk identity
 	// Backup + restore-test state store (slice 6): holds the latest backup-per-target +
 	// latest restore-test result; the collector reads it via the BackupReporter /
 	// RestoreTestReporter seams; the cadence scheduler writes it.
@@ -833,7 +836,25 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	// (The startup self-check log runs AFTER the pbsdr manager is wired below, so its snapshot
 	// already carries the gated view — v0.86.0.)
 	collector.SetCapabilityProber(probeAll)
+	// R-998 (doc 14): the household power-off record of THIS boot rides every report until the box is down.
+	powerOffState := poweroff.New(filepath.Join(cfg.OOB.WithDefaults().StateDir, "poweroff.json"), poweroff.ProcBtime)
+	collector.SetDeliberateOffSource(func() *hub.DeliberateOff {
+		if r := powerOffState.Current(); r != nil {
+			return &hub.DeliberateOff{RequestedAt: r.RequestedAt.UTC().Format(time.RFC3339)}
+		}
+		return nil
+	})
 	loop := hub.NewLoop(collector, client, time.Duration(hcfg.PollSeconds)*time.Second, logger)
+	// R-998: the power-off path waits until the hub ACCEPTED a report carrying the record.
+	powerOffAck := make(chan struct{}, 1)
+	loop.SetReportedHook(func(r *hub.HostReport) {
+		if r != nil && r.DeliberateOff != nil {
+			select {
+			case powerOffAck <- struct{}{}:
+			default:
+			}
+		}
+	})
 	interval := time.Duration(hcfg.PollSeconds) * time.Second
 	// Heartbeat log-pull (v0.83.0): when the control envelope requests it, the NEXT
 	// heartbeat carries the debug ring's tail (newest-kept, byte-capped in the loop).
@@ -877,6 +898,13 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	go osLeg.SendUnsentLoop(ctx, 5*time.Minute, func(n int) {
 		logger.Info("osupdate: sent kept report(s)", "count", n)
 	})
+	// R-836 (`09` §3 decision 172): what became of a kernel step across this boot; on a one-shot boot of a new kernel,
+	// judge it (the host health rule + the hub reached) for KernelJudgeWait, then make it the default or revert ONCE.
+	// The wait: measured 2026-10-07 (`audits/kernel-lane-2026-10-07/B/`) — every container healthy 68 s after the
+	// reboot on demo-felhom and 272 s on demo-hp (the hub reached at 63 s / 189 s); 20 minutes leaves room for a slow
+	// network and stays under the hub's 45-minute host_stale (its
+	// alerting.stale_threshold; host_down at 90). On a box without the kernel lane (an older wrapper, a BYO host) the check is refused and logged.
+	go osLeg.KernelAfterBoot(ctx, 0, osupdate.KernelJudge{Wait: osupdate.DefaultKernelJudgeWait})
 
 	// Reconcile (slice 4) runs alongside the hub loop, sharing the per-guest queue
 	// (doc 03 §10). At slice 4 the desired-state provider is empty (no hub serving
@@ -931,10 +959,7 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	// state. Gates the watchdog's self-heal re-mount to ENROLLED drives, and the local API records
 	// enroll/eject into it. Open failure → ungated legacy remount (logged) so the daemon still runs.
 	var intentReader storage.IntentReader
-	intentStateDir := "/var/lib/felhom-agent"
-	if cfg.Authz.NonceStorePath != "" {
-		intentStateDir = filepath.Dir(cfg.Authz.NonceStorePath) // share the agent's durable state dir
-	}
+	intentStateDir := agentStateDir(cfg)
 	intentStore, ierr := storage.OpenIntentStore(filepath.Join(intentStateDir, "drive-intents.json"))
 	if ierr != nil {
 		logger.Warn("storage: intent store unavailable — self-heal runs UNGATED (legacy remount-any)", "err", ierr)
@@ -1119,6 +1144,16 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 			}
 			return release, nil
 		}}
+	// R-836 (`09` §3 decision 172): a signed kernel step STAGES a kernel on a ring-1 box (install + the one-shot flag,
+	// never a reboot — the night leg reboots it on a night the household was told about); under the heavy-op gate.
+	kernelExec := osupdate.KernelStepExecutor{Leg: osLeg, Guest: firstGuest(px),
+		Gate: func(ctx context.Context) (func(), error) {
+			release, busy, ok := heavyOps.TryAcquire("os-kernel-step")
+			if !ok {
+				return nil, fmt.Errorf("busy: %s", busy)
+			}
+			return release, nil
+		}}
 	// Agent v0.143.0 (R-840): the config bundle — the box's root-owned files by a signed job; the wrapper verifies it.
 	bundleExec := osupdate.ConfigUpdateExecutor{Leg: osLeg, URLTemplate: suCfg.URLTemplate, Username: suCfg.Username, Token: suCfg.Token,
 		// The capability probe confirms from the agent's side: `sudo -l` lists every command the new sudoers grants.
@@ -1130,7 +1165,11 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 			}
 			logger.Warn("osupdate: capability probe after the config bundle", "ok", ok, "total", total, "degraded", strings.Join(names, ","))
 		}}
-	jobsRunner := signedjobs.NewRunner(client, gate, signedjobs.ExecutorChain{wipeExec, decommExec, updateExec, dockerExec, pveExec, bundleExec}, cfg.Hub.HostID, logger)
+	// v0.158.0 (felhom.eu `16` §9): the internal data place on an old box — the root helper, then the mount (late-bound
+	// to the local API server built below).
+	internalPlaceExec := signedjobs.NewInternalPlaceExecutor(suRunner,
+		localapi.InternalPlaceFileIn(intentStateDir), logger)
+	jobsRunner := signedjobs.NewRunner(client, gate, signedjobs.ExecutorChain{wipeExec, decommExec, updateExec, dockerExec, pveExec, kernelExec, bundleExec, internalPlaceExec}, cfg.Hub.HostID, logger)
 	loop.SetEnvelopeObserver(hub.MultiObserver(desiredSyncer, jobsRunner))
 
 	// Controller-driven escrow ceremony (v0.88.0): static config facts + the LATE-BOUND DR gate —
@@ -1163,6 +1202,35 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	}
 	localSrv := buildLocalAPIServer(cfg, px, backupStore, heavyOps, observer, driveKnown, hostOps, gate, collector, client, intentRec, guestBindStore, formatJobStore, logRing, escrowCeremonyCfg, logger, &localTokens)
 	if localSrv != nil {
+		internalPlaceExec.SetEnsure(localSrv.EnsureInternalPlace)
+		// R-998 (doc 14): POST /host/poweroff — guest shutdown, then host power-off; guards in hostpoweroff.go.
+		pwMode := proxmox.RunnerMode(cfg.Privileged.Mode)
+		if pwMode == "" {
+			pwMode = proxmox.RunnerSudo
+		}
+		localSrv.SetHostPowerOff(localapi.HostPowerOffConfig{
+			State: powerOffState,
+			Power: localapi.NewGuestBinder(&proxmox.ExecRunner{Mode: pwMode, SudoPath: cfg.Privileged.SudoPath}, logger),
+			ReportNow: func(ctx context.Context) bool {
+				select {
+				case storageTrigger <- struct{}{}:
+				default: // a report is already queued; it runs after the record was written
+				}
+				select {
+				case <-powerOffAck:
+					return true
+				case <-ctx.Done():
+					return false
+				}
+			},
+			Uptime: func() (time.Duration, bool) {
+				b, err := strconv.ParseInt(poweroff.ProcBtime(), 10, 64)
+				if err != nil || b <= 0 {
+					return 0, false
+				}
+				return time.Since(time.Unix(b, 0)), true
+			},
+		})
 		localSrv.SetAfterPrimaryBackup(func(ctx context.Context, vmid int) {
 			// Let the controller finish bringing its apps back after the backup, then run (still under the gate).
 			select {
@@ -1353,6 +1421,9 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 		// filesystem UUID and re-mounts (idempotent `enable --now`) so a letter reshuffle is a no-op.
 		// Type-asserted (the concrete op exposes it; the interface stays lean).
 		mountReasserter := hostOps // concrete *storage.SudoHostOps — exposes ReassertEnrolledMounts
+		// v0.158.0 (felhom.eu `16` §5): the internal data place is mounted like an enrolled drive — first, so the
+		// re-assert below sees its unit.
+		localSrv.EnsureInternalPlace(ctx)
 		if mountReasserter != nil {
 			mountReasserter.ReassertEnrolledMounts(ctx)
 		}
@@ -1390,6 +1461,7 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 				case <-t.C:
 					// Re-assert mounts first (handles a USB that enumerated late after a host reboot, or a
 					// unit re-disabled at runtime), then re-assert the guest binds against the now-live mounts.
+					localSrv.EnsureInternalPlace(ctx) // `16` §5: a record written since the last tick (the signed job)
 					if mountReasserter != nil {
 						mountReasserter.ReassertEnrolledMounts(ctx)
 					}
@@ -1468,6 +1540,8 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 		// the dangling snapshot → start iff onboot). Runs BEFORE the backup loop starts, so a present
 		// backup lock is stale by definition (guarded by a no-vzdump-running check; fail-safe otherwise).
 		localSrv.RecoverStaleLockedGuests(ctx)
+		// R-1006: then remove a dead half-written backup a power cut left (the lock recovery first: same order as a human).
+		localSrv.SweepVzdumpPartials(ctx)
 		// F-REBOOT: the startup recovery above only covers a guest left LOCKED by an interrupted
 		// backup. A guest that simply ends up stopped-and-unlocked (a `pct reboot` whose shutdown
 		// half completed and whose start half never fired — Campaign 8 fault 11, 9m47s of total
@@ -1828,6 +1902,8 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 	}
 	apiTiers := make([]localapi.BackupTier, 0, len(backupTiers))
 	var runner *backup.BackupRunner
+	var tierRunners []*backup.BackupRunner
+	var tierTargets []string
 	for _, t := range backupTiers {
 		prune := ""
 		if t.KeepLast > 0 {
@@ -1840,6 +1916,8 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		if t.Primary {
 			runner = r
 		}
+		tierRunners = append(tierRunners, r)
+		tierTargets = append(tierTargets, t.TargetID)
 		apiTiers = append(apiTiers, localapi.BackupTier{
 			TargetID:    t.TargetID,
 			Cadence:     t.Cadence,
@@ -1887,11 +1965,15 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 				return nil, 0, ferr
 			}
 			out := make([]escrow.RetainedBlob, 0, len(resp.Packages))
+			// R-304: every package the hub holds and the code will NOT be tried against — no key material,
+			// over the hub's cap, or malformed here. A refusal may call the code wrong only when this is 0.
+			withheld := resp.UnopenableCount + resp.TruncatedCount
 			for _, p := range resp.Packages {
 				blob, derr := base64.StdEncoding.DecodeString(p.IdentityEscrowB64)
 				if derr != nil || len(blob) == 0 {
 					// One malformed package must not sink the rest — the customer's code may open a
 					// later one, and a skipped entry is strictly better than a refusal we cannot justify.
+					withheld++
 					continue
 				}
 				out = append(out, escrow.RetainedBlob{
@@ -1901,9 +1983,13 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 					Index:          p.Index,
 				})
 			}
-			return out, resp.UnopenableCount, nil
+			return out, withheld, nil
 		},
 	}
+	// R-894: ONE instance — the local API writes it, the host report reads it (2026-10-09: a restart right
+	// after the night backup erased the hub's evidence of it).
+	lastKnownBackups := backup.NewBackupSuccessState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "backup-success-state.json"))
+	collector.SetKnownBackupReporter(lastKnownBackups)
 	srv, err := localapi.NewServer(localapi.Options{
 		EscrowRecovery: escrowRecoverer,
 		ListenAddr:     cfg.LocalAPI.ListenAddr,
@@ -1916,11 +2002,12 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		Store:          store,
 		// R-894: the newest success per tier on disk — the due-check's fallback when the storage cannot be
 		// read right after a restart. Same state dir as restore-test-state.json.
-		LastKnownBackups: backup.NewBackupSuccessState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "backup-success-state.json")),
+		LastKnownBackups: lastKnownBackups,
 		Storage:          observer,
 		DriveTargets:     driveTargets,                    // Impl-2a: registry+units drives for the /disks view (union w/ Observe storages)
 		Smart:            storage.NewSmartReader(hostOps), // v0.95.0 Fix B: SMART for the union-path drives
 		HostReader:       storage.NewProcHostReader(),     // Impl-2b: durableIDForMount raw-mount fallback + role gate
+		Identity:         storage.NewIdentityResolver(),   // v0.157.0: `16` §3 identity on /disks + POST /disks/same-disk
 		Tokens:           tokens,
 		BackupCadence:    cfg.Backup.BackupCadence(),
 		// Disk management (slice 8C): the privileged host surface + the data-bearing wipe gate.
@@ -1942,10 +2029,12 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		// F2-b: recover a guest left with a stale vzdump lock by a reboot-during-backup. Reads + start
 		// go through the API client; the `pct unlock` is the one fenced root-CLI op (no API equivalent).
 		// A1 (v0.62.0): the scan is restricted to felhom-pool members (ownership proven, not assumed).
-		StaleLock:  localapi.NewStaleLockController(px, &proxmox.ExecRunner{Mode: gaMode, SudoPath: cfg.Privileged.SudoPath}, reconcile.DefaultPool, logger),
-		Intent:     intent,     // slice 10 P3: record enroll/eject intent for self-heal
-		GuestBinds: guestBinds, // F9: per-guest bind record for the startup re-assert
-		FormatJobs: formatJobs, // F20-BUG3: detached-format job record + restart recovery
+		StaleLock: localapi.NewStaleLockController(px, &proxmox.ExecRunner{Mode: gaMode, SudoPath: cfg.Privileged.SudoPath}, reconcile.DefaultPool, logger),
+		Intent:    intent, // slice 10 P3: record enroll/eject intent for self-heal
+		// v0.158.0 (felhom.eu `16` §5): the internal data place record, beside the intent store.
+		InternalPlaceFile: localapi.InternalPlaceFileIn(agentStateDir(cfg)),
+		GuestBinds:        guestBinds, // F9: per-guest bind record for the startup re-assert
+		FormatJobs:        formatJobs, // F20-BUG3: detached-format job record + restart recovery
 
 		// Host metrics (slice 9): the shared collector serves GET /host/metrics — a fresh host +
 		// per-storage view to the customer's monitoring page (reuses the slice-4 collector).
@@ -1960,6 +2049,26 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		logger.Warn("daemon: local-api disabled (server build)", "err", err)
 		return nil
 	}
+	// R-1006: a dead half-written vzdump (a power cut mid-backup) is removed at start-up and before every backup of the
+	// guest on that target, through the root helper; the in-flight answer is R-1008's (a task from before the boot is dead).
+	cleaner := &vzpartial.Cleaner{
+		API:      px,
+		Runner:   &proxmox.ExecRunner{Mode: gaMode, SudoPath: cfg.Privileged.SudoPath},
+		InFlight: srv.VzdumpInFlight,
+		Boot: func() (int64, bool) {
+			b, err := strconv.ParseInt(poweroff.ProcBtime(), 10, 64)
+			return b, err == nil && b > 0
+		},
+		Logger: logger,
+	}
+	for _, r := range tierRunners {
+		r.SetBeforeBackup(func(ctx context.Context, storage string, vmid int) { cleaner.Clean(ctx, storage, vmid) })
+	}
+	srv.SetPartialSweep(func(ctx context.Context, vmid int) {
+		for _, t := range tierTargets {
+			cleaner.Clean(ctx, t, vmid)
+		}
+	})
 	return srv
 }
 
@@ -2089,6 +2198,7 @@ func runSelftestHub(ctx context.Context, cfg config.Config, logger *slog.Logger)
 		return 1
 	}
 	observer := storage.NewObserver(px, storage.NewProcHostReader(), newHostOps(cfg, logger), logger)
+	observer.SetIdentity(storage.NewIdentityResolver()) // `16` §3 physical-disk identity
 	// Wire the LIVE PBS reporter here too (v0.39.0): selftest=hub is a separate one-shot process — no
 	// verify loop runs — so a nil reporter previously yielded pbs_snapshots:[] and an absent dr_recipe
 	// pbs coord. The live reporter lists snapshots directly (fresh store, last-known-good fallback) so
@@ -2145,6 +2255,7 @@ func runSelftestStorage(ctx context.Context, cfg config.Config, logger *slog.Log
 	hostReader := storage.NewProcHostReader()
 	hostOps := newHostOps(cfg, logger)
 	observer := storage.NewObserver(px, hostReader, hostOps, logger)
+	observer.SetIdentity(storage.NewIdentityResolver()) // `16` §3 physical-disk identity
 
 	octx, cancel := context.WithTimeout(ctx, 60*time.Second)
 	fmt.Printf("=== felhom-agent %s selftest=storage ===\n", version)
@@ -3802,3 +3913,12 @@ func (f *factsReporter) SystemFacts(ctx context.Context) (int, json.RawMessage,
 	f.facts, f.err = f.leg.Facts(ctx, f.vmid)
 	return f.vmid, f.facts, f.err
 }
+
+// agentStateDir is the agent's durable state dir: beside the nonce store when one is configured, else the default.
+// The intent store, the guest-bind record and the internal place record (v0.158.0) all live here.
+func agentStateDir(cfg config.Config) string {
+	if cfg.Authz.NonceStorePath != "" {
+		return filepath.Dir(cfg.Authz.NonceStorePath)
+	}
+	return "/var/lib/felhom-agent"
+}

cmd/felhom-agent/r894_wiring_test.go

@@ -12,12 +12,18 @@ import (
 //
 // COMPANION RED-PROOF (observed): delete the `LastKnownBackups:` line from buildLocalAPIServer → this
 // fails with "localapi.Options in buildLocalAPIServer has no LastKnownBackups field". Restored.
+//
+// 2026-10-09: the SAME instance also feeds the host report (collector.SetKnownBackupReporter), so a
+// restart right after a backup no longer erases the hub's evidence of it. The field may name a local
+// variable; the variable must be built by backup.NewBackupSuccessState and be the one handed to the
+// collector. RED-PROOF (observed): drop the SetKnownBackupReporter call → "not handed to the collector".
 func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 	_, f := parseMain(t)
 	if !callsWithin(f, "main")["runDaemon"] || !callsWithin(f, "runDaemon")["buildLocalAPIServer"] {
 		t.Fatal("main → runDaemon → buildLocalAPIServer is broken — the path this test asserts is not the live one")
 	}
 	var field, built bool
+	var fieldVar, handed string
 	for _, d := range f.Decls {
 		fd, ok := d.(*ast.FuncDecl)
 		if !ok || fd.Name == nil || fd.Name.Name != "buildLocalAPIServer" || fd.Body == nil {
@@ -45,6 +51,28 @@ func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 					if callsIn(kv.Value)["backup.NewBackupSuccessState"] {
 						built = true
 					}
+					if id, ok := kv.Value.(*ast.Ident); ok {
+						fieldVar = id.Name
+					}
+				}
+			}
+			return true
+		})
+		// a local variable: built by NewBackupSuccessState, and handed to the collector
+		ast.Inspect(fd.Body, func(n ast.Node) bool {
+			switch x := n.(type) {
+			case *ast.AssignStmt:
+				for i, l := range x.Lhs {
+					if id, ok := l.(*ast.Ident); ok && fieldVar != "" && id.Name == fieldVar && i < len(x.Rhs) &&
+						callsIn(x.Rhs[i])["backup.NewBackupSuccessState"] {
+						built = true
+					}
+				}
+			case *ast.CallExpr:
+				if fn, ok := x.Fun.(*ast.SelectorExpr); ok && fn.Sel.Name == "SetKnownBackupReporter" && len(x.Args) == 1 {
+					if id, ok := x.Args[0].(*ast.Ident); ok {
+						handed = id.Name
+					}
 				}
 			}
 			return true
@@ -56,6 +84,9 @@ func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 	if !built {
 		t.Fatal("LastKnownBackups is not built by backup.NewBackupSuccessState")
 	}
+	if handed == "" || handed != fieldVar {
+		t.Fatalf("the saved backups (%q) are not handed to the collector (SetKnownBackupReporter got %q)", fieldVar, handed)
+	}
 }
 
 func callsIn(n ast.Node) map[string]bool {

cmd/felhom-opsign/main.go

@@ -43,7 +43,7 @@ func main() {
 
 func run() error {
 	var (
-		op        = flag.String("op", "", "op class to sign, e.g. storage_wipe | guest_destroy | decommission | agent_update | os_docker_step | os_pve_step | agent_config_update")
+		op        = flag.String("op", "", "op class to sign, e.g. storage_wipe | guest_destroy | decommission | agent_update | os_docker_step | os_pve_step | os_kernel_step | agent_config_update | add_internal_place")
 		host      = flag.String("host", "", "target host_id (anti-retarget — the op runs ONLY on this host)")
 		guest     = flag.String("guest", "", "target guest_id (\"\" = host-scoped op)")
 		keyID     = flag.String("key-id", "", "key id of the signing key (must match a pinned agent signer)")

configs/felhom-agent.sudoers

@@ -80,7 +80,29 @@ Cmnd_Alias FELHOM_DNSMASQ = \
 Cmnd_Alias FELHOM_GUESTHOOK = \
   /usr/sbin/pct ^set [0-9]+ --hookscript local\:snippets/felhom-guest-hook\.sh$, \
   /usr/sbin/pct ^set [0-9]+ --delete mp[0-9]+$, \
-  /usr/sbin/pct ^reboot [0-9]+$
+  /usr/sbin/pct ^reboot [0-9]+$, \
+  /usr/sbin/pct ^shutdown [0-9]+ --timeout [0-9]+$
+
+# Host power-off (R-998, doc 14): the household's „A gép kikapcsolása" — guest shutdown above, then this one fixed
+# vector. Guarded agent-side (10 min after boot, one per boot, never during a backup/restore/update/drive job).
+Cmnd_Alias FELHOM_POWEROFF = \
+  /usr/bin/systemctl poweroff
+
+# Dead half-written vzdump removal (R-1006, power-cut-fixes-2026-10-14): a power cut mid-backup leaves
+# vzdump-lxc-<vmid>-<date>.tar.dat + .tmp/ on the dir storage; nothing removed them and every later backup was skipped
+# „not enough space". ONE root helper (configs/felhom-vzdump-partial-clean, from the config bundle) re-checks everything
+# as root — a dir storage from storage.cfg, the exact name of THAT vmid, not in use, dead — and refuses otherwise. The
+# arguments here are its exact shape (storage id, vmid, one half-written name); the vmid-in-name match is the helper's.
+Cmnd_Alias FELHOM_VZPARTIAL = \
+  /usr/local/sbin/felhom-vzdump-partial-clean ^[A-Za-z][A-Za-z0-9_-]{0\,63} [1-9][0-9]{2\,8} vzdump-(lxc|qemu)-[1-9][0-9]{2\,8}-[0-9]{4}_[0-9]{2}_[0-9]{2}-[0-9]{2}_[0-9]{2}_[0-9]{2}\.(tar\.dat|vma\.dat|tmp)$
+
+# Internal data place („Belső tárhely", felhom.eu architecture/16 §5, §7; agent v0.158.0). ONE root helper
+# (configs/felhom-internal-place, from the config bundle) creates <vg>/felhom-belso in the local-lvm thin pool by the
+# ruled size rule and formats ONLY that volume, ONLY when it carries no signature. The agent calls it from the signed
+# `add_internal_place` job (an old box), always with 0 GiB planned: its guest's volumes already exist. `plan` changes
+# nothing. The installer runs the helper as root itself (a new box).
+Cmnd_Alias FELHOM_INTERNALPLACE = \
+  /usr/local/sbin/felhom-internal-place ^(plan|create) 0$
 
 # Intermediary mount model (the drive hot-swap re-architecture). The agent keeps a SHARED host parent
 # /mnt/felhom-drives (self-bind + make-shared) and binds/unbinds each drive's felhom-data namespace UNDERNEATH it so the
@@ -314,4 +336,4 @@ Cmnd_Alias FELHOM_GUESTNET = \
   /usr/sbin/pct ^exec [0-9]+ -- pgrep -x dhclient$, \
   /usr/sbin/pct ^exec [0-9]+ -- dhclient -pf /run/dhclient\.eth0\.pid -lf /var/lib/dhcp/dhclient\.eth0\.leases eth0$
 
-felhom-agent ALL=(root) NOPASSWD: FELHOM_MOUNT, FELHOM_DISK, FELHOM_PROVISION, FELHOM_FORMAT, FELHOM_DNSMASQ, FELHOM_GUESTHOOK, FELHOM_INTERMEDIARY, FELHOM_CONTROLLERSWAP, FELHOM_STALELOCK, FELHOM_FSTRIM, FELHOM_NETMOUNT, FELHOM_WG, FELHOM_SELFUPDATE, FELHOM_SSHD, FELHOM_OOB, FELHOM_PBSDR, FELHOM_BACKUPTARGET, FELHOM_SELFHEAL, FELHOM_ESCROW, FELHOM_GUESTNET, FELHOM_SCRATCH_TEARDOWN, FELHOM_OSAPPLY
+felhom-agent ALL=(root) NOPASSWD: FELHOM_MOUNT, FELHOM_DISK, FELHOM_PROVISION, FELHOM_FORMAT, FELHOM_DNSMASQ, FELHOM_GUESTHOOK, FELHOM_INTERMEDIARY, FELHOM_CONTROLLERSWAP, FELHOM_STALELOCK, FELHOM_FSTRIM, FELHOM_NETMOUNT, FELHOM_WG, FELHOM_SELFUPDATE, FELHOM_SSHD, FELHOM_OOB, FELHOM_PBSDR, FELHOM_BACKUPTARGET, FELHOM_SELFHEAL, FELHOM_ESCROW, FELHOM_GUESTNET, FELHOM_SCRATCH_TEARDOWN, FELHOM_OSAPPLY, FELHOM_POWEROFF, FELHOM_VZPARTIAL, FELHOM_INTERNALPLACE

configs/felhom-grub-oneshot-entries.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+# /etc/grub.d/42_felhom_oneshot — the kernel lane's one-shot ENTRIES (R-836, `09` §3 decision 172, `11` §5.11).
+# Installed by the config bundle (felhom-os-apply BUNDLE_FILES), 0755 root. update-grub runs it.
+#
+# One menu entry per installed Proxmox kernel, id `felhom-oneshot-<version>`, booted ONLY when 01_felhom_oneshot found
+# the flag naming it. It is the normal entry plus option C (decision 172): softlockup_panic=1 hardlockup_panic=1
+# hung_task_panic=1 panic=10 — a lockup the kernel can detect becomes a panic, and a panic restarts the box in 10 s into
+# the default (the old kernel). A true dead freeze still needs a person (spike candidate 3 failed on all three boxes).
+# It sorts AFTER 10_linux, so it is never entry 0 and never the default.
+#
+# No vfat ESP at /boot/efi → prints nothing (no flag can name these entries).
+set -e
+prefix="/usr"
+exec_prefix="/usr"
+datarootdir="/usr/share"
+. "$datarootdir/grub/grub-mkconfig_lib"
+esp_uuid=$(findmnt -n -o UUID,FSTYPE /boot/efi 2>/dev/null | awk '$2 == "vfat" { print $1 }')
+[ -n "$esp_uuid" ] || exit 0
+kernels=$(ls /boot/vmlinuz-*-pve 2>/dev/null | sed 's#^/boot/vmlinuz-##' | grep -E '^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$' || true)
+[ -n "$kernels" ] || exit 0
+case "${GRUB_DEVICE}" in
+    /dev/mapper/*|/dev/dm-*|"") root_arg="root=${GRUB_DEVICE}" ;;
+    *) if [ -n "${GRUB_DEVICE_UUID}" ]; then root_arg="root=UUID=${GRUB_DEVICE_UUID}"; else root_arg="root=${GRUB_DEVICE}"; fi ;;
+esac
+[ -n "${GRUB_DEVICE}" ] || root_arg="root=$(findmnt -n -o SOURCE /)"
+rel=$(make_system_path_relative_to_its_root /boot)
+prep=$(prepare_grub_to_access_device "$(${grub_probe:-grub-probe} --target=device /boot)" | sed 's/^/  /')
+for k in $kernels; do
+    [ -f "/boot/initrd.img-$k" ] || continue
+    cat <<EOF
+menuentry 'Felhom one-shot: $k' --class proxmox --id felhom-oneshot-$k {
+  insmod gzio
+$prep
+  echo 'Loading Linux $k (felhom one-shot) ...'
+  linux $rel/vmlinuz-$k $root_arg ro ${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10
+  initrd $rel/initrd.img-$k
+}
+EOF
+done

configs/felhom-grub-oneshot.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+# /etc/grub.d/01_felhom_oneshot — the kernel lane's ONE-SHOT boot (R-836, `09` §3 decisions 164 + 172, `11` §5.11).
+# Installed by the config bundle (felhom-os-apply BUNDLE_FILES), 0755 root. update-grub runs it; it prints GRUB script.
+#
+# At boot, GRUB reads `felhom_next` from an environment block on the ESP (vfat — GRUB can rewrite a file there; it
+# cannot on the LVM /boot, R-836), CLEARS it, and — only if it names an installed kernel — boots that kernel's one-shot
+# entry (42_felhom_oneshot) instead of the default. The next boot uses the default again whatever happens: a new kernel
+# that panics comes back on the old one by itself. felhom-os-apply writes the flag (mode apply) and never the default
+# for a new kernel. Measured on the Tester 1 VM, demo-felhom and demo-hp (Secure Boot on):
+# `audits/kernel-spike-2026-10-07/` (candidate 2).
+#
+# No vfat ESP at /boot/efi, or no Proxmox kernel → prints nothing (the box boots exactly as before).
+set -e
+esp_uuid=$(findmnt -n -o UUID,FSTYPE /boot/efi 2>/dev/null | awk '$2 == "vfat" { print $1 }')
+[ -n "$esp_uuid" ] || exit 0
+kernels=$(ls /boot/vmlinuz-*-pve 2>/dev/null | sed 's#^/boot/vmlinuz-##' | grep -E '^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$' || true)
+[ -n "$kernels" ] || exit 0
+cat <<EOF
+# felhom kernel lane: a one-shot kernel named on the ESP, read and cleared before the menu
+insmod part_gpt
+insmod fat
+search --no-floppy --fs-uuid --set=felhom_esp $esp_uuid
+if [ -f (\$felhom_esp)/EFI/felhom/oneshot.env ]; then
+  load_env -f (\$felhom_esp)/EFI/felhom/oneshot.env felhom_next
+  if [ "\${felhom_next}" ]; then
+    set felhom_boot="\${felhom_next}"
+    set felhom_next=
+    save_env -f (\$felhom_esp)/EFI/felhom/oneshot.env felhom_next
+EOF
+for k in $kernels; do
+    printf '    if [ "${felhom_boot}" = "%s" ]; then set default="felhom-oneshot-%s"; fi\n' "$k" "$k"
+done
+cat <<EOF
+  fi
+fi
+EOF

configs/felhom-internal-place

@@ -0,0 +1,118 @@
+#!/bin/bash
+# felhom-internal-place — make the one-disk box's internal data place („Belső tárhely"), felhom.eu
+# architecture/16-storage-physical-identity.md §5, §7 (sizes ruled by the operator 2026-10-16). Installed as
+# /usr/local/sbin/felhom-internal-place (config bundle). Called by felhom-host-install.sh (a new box) and by the agent's
+# signed `add_internal_place` job (an old box) — ONE implementation of the size rule and of the only mkfs it does.
+#
+#   felhom-internal-place plan   <planned GiB>   → prints the numbers, changes nothing
+#   felhom-internal-place create <planned GiB>   → makes the place (or finds it), prints the result
+#
+# <planned GiB> is thin space still to be promised to the guest (rootfs + data volume) that does not exist yet:
+# the installer passes 32 + the data volume; an old box passes 0 (its guest's volumes are already counted).
+#
+# The rule (16 §7, ruled): reserve = max(16 GiB, 10 % of the pool), at most 48 GiB; internal = pool − reserve −
+# every thin volume already promised in the pool − <planned>, made only when ≥ 20 GiB. So nothing in the pool is ever
+# promised beyond pool − reserve: a pool at 100 % stops every volume on the box.
+#
+# It trusts nothing it is told. Every rule is checked here, as root, and any doubt REFUSES (exit 1):
+#   - the pool is the `lvmthin: local-lvm` section of /etc/pve/storage.cfg (its vgname/thinpool), nothing else;
+#   - the only volume it creates, formats or reads is <vg>/felhom-belso;
+#   - it formats ONLY a felhom-belso that carries no signature at all (blkid -p finds nothing) — the one it just made,
+#     or one a crash left between lvcreate and mkfs; any other content REFUSES; it never resizes or removes anything.
+# Output, one line: „created uuid=<fs-uuid> gib=<n>", „formatted uuid=… gib=…" (a crash left it empty), „existing uuid=<fs-uuid> gib=<n>", „skipped <why>" (exit 0),
+# or „plan pool=… reserve=… promised=… planned=… internal=…". Pinned by configs/test_felhom_internal_place.py.
+set -u
+STORAGE_CFG=${FELHOM_STORAGE_CFG:-/etc/pve/storage.cfg}
+LV_NAME=felhom-belso
+LABEL=felhom-belso
+MIN_GIB=20
+
+die() { echo "felhom-internal-place: REFUSED: $*" >&2; exit 1; }
+
+pool_of_local_lvm() { # prints "<vg> <thinpool>" of the lvmthin storage local-lvm, or nothing
+	awk '
+		/^[a-z]+:[ \t]/ { split($0, h, /:[ \t]+/); type = h[1]; id = h[2]; sub(/[ \t]+$/, "", id); in_s = (type == "lvmthin" && id == "local-lvm"); next }
+		in_s && /^[ \t]+vgname[ \t]/ { vg = $2 }
+		in_s && /^[ \t]+thinpool[ \t]/ { tp = $2 }
+		END { if (vg != "" && tp != "") print vg, tp }
+	' "$STORAGE_CFG"
+}
+
+gib_floor() { echo $(( $1 / 1073741824 )); }
+
+[[ $# -eq 2 ]] || die "usage: felhom-internal-place plan|create <planned GiB>"
+MODE=$1; PLANNED=$2
+[[ "$MODE" == plan || "$MODE" == create ]] || die "mode must be plan or create"
+[[ "$PLANNED" =~ ^(0|[1-9][0-9]{0,5})$ ]] || die "planned GiB must be a whole number"
+
+read -r VG POOL < <(pool_of_local_lvm) || true
+[[ -n "${VG:-}" && -n "${POOL:-}" ]] || die "no lvmthin storage local-lvm in $STORAGE_CFG"
+[[ "$VG" =~ ^[A-Za-z0-9_.+-]+$ && "$POOL" =~ ^[A-Za-z0-9_.+-]+$ ]] || die "unexpected vg/pool name"
+
+pool_b=$(lvs --noheadings --nosuffix --units b -o lv_size "$VG/$POOL" 2>/dev/null | tr -d ' ')
+[[ "$pool_b" =~ ^[0-9]+$ ]] || die "cannot read the size of $VG/$POOL"
+pool_gib=$(gib_floor "$pool_b")
+
+# Every thin volume promised in the pool (its virtual size) — except the place itself and vzdump's short-lived
+# snapshots (snap_*_vzdump), which exist only during a whole-box copy and are what the reserve is for.
+# FAIL CLOSED: a failed or empty listing must never read as „nothing promised" (that would size the place too big).
+listing=$(lvs --noheadings --nosuffix --units b -o lv_name,pool_lv,lv_size "$VG" 2>/dev/null) || die "cannot list the volumes of $VG"
+pool_seen=false; promised_b=0; have_lv=false
+while read -r name pl size; do
+	[[ -n "${name:-}" ]] || continue
+	[[ "$name" == "$POOL" ]] && pool_seen=true
+	[[ "$pl" == "$POOL" ]] || continue
+	if [[ "$name" == "$LV_NAME" ]]; then have_lv=true; continue; fi
+	[[ "$name" =~ ^snap_.*_vzdump$ ]] && continue
+	[[ "$size" =~ ^[0-9]+$ ]] || die "cannot read the size of $VG/$name"
+	promised_b=$(( promised_b + size ))
+done <<< "$listing"
+$pool_seen || die "the listing of $VG does not contain the pool $POOL — refusing to guess what is promised"
+promised_gib=$(( (promised_b + 1073741823) / 1073741824 ))   # rounded UP: never promise a partial GiB twice
+
+reserve=$(( pool_gib / 10 )); (( reserve < 16 )) && reserve=16; (( reserve > 48 )) && reserve=48
+internal=$(( pool_gib - reserve - promised_gib - PLANNED ))
+
+if [[ "$MODE" == plan ]]; then
+	echo "plan pool=$pool_gib reserve=$reserve promised=$promised_gib planned=$PLANNED internal=$internal exists=$have_lv"
+	exit 0
+fi
+
+DEV=/dev/$VG/$LV_NAME
+is_block() { [[ "$(stat -L -c %F "$1" 2>/dev/null)" == "block special file" ]]; }
+fs_uuid() { blkid -p -s UUID -o value "$DEV" 2>/dev/null; }
+fs_type() { blkid -p -s TYPE -o value "$DEV" 2>/dev/null; }
+fs_label() { blkid -p -s LABEL -o value "$DEV" 2>/dev/null; }
+# has_signature: FAIL CLOSED. blkid -p exits 0 when it found something and 2 when it found NOTHING; any other result (an
+# error, an ambivalent probe, blkid missing) must never read as „empty" — that is the only gate in front of mkfs.
+has_signature() {
+	local rc=0
+	blkid -p -o value "$DEV" >/dev/null 2>&1 || rc=$?
+	case $rc in
+		0) return 0 ;;
+		2) return 1 ;;
+		*) die "cannot probe $DEV for a signature (blkid exit $rc) — refusing" ;;
+	esac
+}
+lv_gib() { gib_floor "$(lvs --noheadings --nosuffix --units b -o lv_size "$VG/$LV_NAME" 2>/dev/null | tr -d ' ')"; }
+
+if $have_lv; then
+	is_block "$DEV" || die "$DEV is not an active block device"
+	t=$(fs_type)
+	if [[ -n "$t" ]]; then
+		[[ "$t" == ext4 && "$(fs_label)" == "$LABEL" ]] || die "$DEV holds something that is not Felhom's ($t) — left alone"
+		echo "existing uuid=$(fs_uuid) gib=$(lv_gib)"; exit 0
+	fi
+	# A felhom-belso with NO signature: a crash between lvcreate and mkfs. Nothing can be on it — format it.
+	has_signature && die "$DEV carries a signature blkid cannot name — left alone"
+else
+	(( internal >= MIN_GIB )) || { echo "skipped only $internal GiB free for it (pool $pool_gib, reserve $reserve, promised $promised_gib, planned $PLANNED; needs $MIN_GIB)"; exit 0; }
+	lvcreate -q -y -V "${internal}G" -T "$VG/$POOL" -n "$LV_NAME" >/dev/null || die "lvcreate failed"
+	is_block "$DEV" || die "$DEV did not appear after lvcreate"
+	has_signature && die "the new $DEV already carries a signature — left alone"
+	made=created
+fi
+mkfs.ext4 -q -L "$LABEL" "$DEV" >/dev/null || die "mkfs.ext4 failed on $DEV"
+u=$(fs_uuid)
+[[ "$u" =~ ^[0-9a-fA-F-]{36}$ ]] || die "no filesystem UUID after mkfs on $DEV"
+echo "${made:-formatted} uuid=$u gib=$(lv_gib)"

configs/felhom-mkfs-guarded.sh

@@ -58,14 +58,26 @@ fi
 
 # 3) mounted OUTSIDE Felhom's own drive area = a live foreign filesystem → catastrophic. Mounts under
 #    /mnt/felhom-drives are our own drives (the agent detaches before a re-init) → allowed.
-while read -r mp; do
-  [[ -z "$mp" ]] && continue
-  case "$mp" in
-    /mnt/felhom-drives|/mnt/felhom-drives/*) : ;;
-    *) die "device (or a partition) is mounted at $mp ($dev)" ;;
-  esac
-done < <(lsblk -nro MOUNTPOINT "$whole" 2>/dev/null || true)
-
+#    Agent v0.158.0: read from the kernel's mount table for EVERY node of the disk (lsblk's MOUNTPOINT shows one mount
+#    per node; a bind elsewhere hid behind it), and a disk whose nodes cannot be listed REFUSES (it passed before).
+#    Deliberately NO exemption for a sibling that is Felhom's own enrolled drive (raw /mnt/<name> + /mnt/felhom-drives):
+#    the only corroboration available here is a mount the agent itself can make, so trusting it would let a compromised
+#    agent unlock a host owner's disk. Consequence (felhom.eu `16` §13): the free part next to an in-use Felhom drive
+#    cannot be formatted; the dashboard does not offer it.
+PROC_MOUNTS=/proc/mounts
+node_mounts() { awk -v d="$1" '$1 == d { print $2 }' "$PROC_MOUNTS"; }
+disk_nodes="$(lsblk -nrpo NAME "$whole" 2>/dev/null || true)"
+[[ -n "$disk_nodes" ]] || die "cannot list the nodes of $whole — refusing"
+while read -r node; do
+  [[ -z "$node" ]] && continue
+  while read -r mp; do
+    [[ -z "$mp" ]] && continue
+    case "$mp" in
+      /mnt/felhom-drives|/mnt/felhom-drives/*) : ;;
+      *) die "device (or a partition) is mounted at $mp ($node)" ;;
+    esac
+  done < <(node_mounts "$node")
+done <<< "$disk_nodes"
 # 4) read-only device (audit D1): a device the kernel marks RO is never a formattable data disk.
 wbase="${whole#/dev/}"
 rof="/sys/block/$wbase/ro"

configs/felhom-os-apply

@@ -93,8 +93,13 @@ OOMCHECK_TIMEOUTS = {"image": 10, "clock": 5, "run": 30, "inspect": 10, "events"
 OOMCHECK_SETTLE = 2
 # Kernel, boot and firmware packages are the SLOW lane on the host whatever their origin (`11` C3, §5.2): a host
 # reboot is needed for them to take effect, and a bad one can stop the box from booting.
+# proxmox-secure-boot-support is the Secure Boot meta-package: its only job is to pull shim-signed and the signed GRUB,
+# so it belongs with them. Measured 2026-10-09 on demo-hp (Secure Boot on): left in the pve lane, its upgrade pulled
+# shim-signed-common, the whole pve step was refused R6, and the night's kernel step was skipped with it
+# (`audits/kernel-night-2026-10-08/`). Pinned by test_ring0_pending_pve_leaves_the_secure_boot_meta_out.
 HOST_SLOW_RE = re.compile(r"^(linux-(image|headers|kbuild|modules|base)|proxmox-kernel|proxmox-default-kernel|pve-kernel|"
-                          r"pve-firmware|firmware-|grub|shim|systemd-boot|intel-microcode|amd64-microcode|efibootmgr)")
+                          r"pve-firmware|firmware-|grub|shim|systemd-boot|intel-microcode|amd64-microcode|efibootmgr|"
+                          r"proxmox-secure-boot-support)")
 # restart_needed() leaves out processes whose cgroup line matches (grep basic regex). Host: the LXC guests' own
 # processes (`0::/lxc/<vmid>/...`) -- NOT lxc-start itself, whose cgroup is `0::/lxc.monitor/<vmid>` (measured
 # 2026-10-04 on demo-felhom: the old pattern "lxc" hid lxc-start with 20 deleted maps, so "reboot needed" stayed false
@@ -124,6 +129,32 @@ DAEMON_JSON = "/etc/docker/daemon.json"
 # wrapper restarts exactly the containers that mount one of these paths (never the apps, never the engine).
 DOCKER_SOCKETS = ("/var/run/docker.sock", "/run/docker.sock")
 CRASH_GUARD_STATE = "/var/lib/felhom-crash-guard/state.json"
+# ---------- the kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11) ----------
+# A new kernel boots ONCE through a flag in a GRUB environment block on the ESP (vfat — GRUB can rewrite it there; on
+# the LVM /boot it cannot, R-836). The bundle's two GRUB generators read and clear the flag (01_felhom_oneshot) and
+# give each installed kernel a one-shot entry with the lockup-to-panic options (42_felhom_oneshot, option C). The GRUB
+# default is the kernel the box RUNS, pinned in KERNEL_DEFAULT_CFG; only "kernel-good" (after a healthy one-shot boot)
+# moves it to the new kernel. Measured in the spike on the Tester 1 VM, demo-felhom and demo-hp (Secure Boot on):
+# `audits/kernel-spike-2026-10-07/`.
+KERNEL_OP = "os_kernel_step"
+KERNEL_STATE = "/var/lib/felhom-kernel/state.json"          # 0644 root: the step's phase (the agent reads it)
+KERNEL_DEFAULT_CFG = "/etc/default/grub.d/zz-felhom-kernel-default.cfg"  # sourced last: GRUB_DEFAULT = this kernel
+ONESHOT_SNIPPET = "/etc/grub.d/01_felhom_oneshot"           # bundle-owned: read + clear the flag, pick the entry
+ONESHOT_ENTRIES = "/etc/grub.d/42_felhom_oneshot"           # bundle-owned: the one-shot entries (option C options)
+GRUB_CFG = "/boot/grub/grub.cfg"
+ESP_MOUNT = "/boot/efi"
+ONESHOT_ENV = ESP_MOUNT + "/EFI/felhom/oneshot.env"
+ONESHOT_ARGS = "softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10"
+KERNEL_PIN_FILE = "/etc/kernel/proxmox-boot-pin"            # an operator's `proxmox-boot-tool kernel pin` — never fought
+KVER_RE = re.compile(r"^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$")
+KERNEL_IMAGE_RE = re.compile(r"^proxmox-kernel-([0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve)(-signed)?$")
+# the packages a kernel step may UPGRADE (never add): the kernel series meta-package, the default-kernel meta, the boot
+# helper and the firmware the kernel loads. Everything else in HOST_SLOW_RE (grub, shim, microcode, efibootmgr) stays out.
+KERNEL_UPGRADE_RE = re.compile(r"^(proxmox-default-kernel|proxmox-kernel-[0-9]+\.[0-9]+|proxmox-kernel-helper|pve-firmware)$")
+KERNEL_MIN_GAP = 20 * 3600     # never two kernel steps in one night
+KERNEL_MODES = ("kernel-status", "kernel-reboot", "kernel-boot", "kernel-good", "kernel-revert", "kernel-cancel")
+# phases: staged → oneshot → judging → good | reverting → self_reverted | revert_failed; oneshot → fell_back; staged → cancelled
+KERNEL_ACTIVE = ("staged", "oneshot", "judging", "reverting")
 
 # ---------- the config bundle (R-840, agent v0.143.0, `11` §5.4.2) ----------
 # A signed `agent_config_update` job carries {agent_version, bundle_sha256}; the bundle is ONE JSON file built from this
@@ -158,6 +189,10 @@ BUNDLE_FILES = [
     ("/usr/local/sbin/felhom-selfupdate-guarded", "felhom-selfupdate-guarded", 0o755, "sh", "replace"),
     ("/usr/local/sbin/felhom-pbs-apply", "felhom-pbs-apply", 0o755, "bash", "replace"),
     ("/usr/local/sbin/felhom-backup-target-apply", "felhom-backup-target-apply", 0o755, "bash", "replace"),
+    # R-1006 (agent v0.156.0): the only delete of backup files — a dead half-written vzdump, re-checked as root.
+    ("/usr/local/sbin/felhom-vzdump-partial-clean", "felhom-vzdump-partial-clean", 0o755, "bash", "replace"),
+    # felhom.eu architecture/16 §5 (agent v0.158.0): the internal data place — the only lvcreate/mkfs of a system-disk volume.
+    ("/usr/local/sbin/felhom-internal-place", "felhom-internal-place", 0o755, "bash", "replace"),
     ("/usr/local/sbin/felhom-os-apply", "felhom-os-apply", 0o755, "python", "replace"),
     ("/usr/local/sbin/felhom-crash-guard", "felhom-crash-guard", 0o755, "python", "replace"),
     # R-861 (agent v0.146.0): the content checker for every agent-staged file a root program reads, and the two FIXED
@@ -170,6 +205,10 @@ BUNDLE_FILES = [
     ("/etc/systemd/system/felhom-crash-guard-check.service", "felhom-crash-guard-check.service", 0o644, "unit", "replace"),
     ("/etc/systemd/system/felhom-crash-guard-check.timer", "felhom-crash-guard-check.timer", 0o644, "unit", "replace"),
     ("/etc/felhom/crash-guard.conf", "crash-guard.conf", 0o644, "plain", "if-absent"),
+    # the kernel lane's two GRUB generators (R-836, `11` §5.11): they take effect at the next update-grub, which the
+    # first kernel step runs itself; with no flag on the ESP they change nothing about how the box boots.
+    ("/etc/grub.d/01_felhom_oneshot", "felhom-grub-oneshot.sh", 0o755, "sh", "replace"),
+    ("/etc/grub.d/42_felhom_oneshot", "felhom-grub-oneshot-entries.sh", 0o755, "sh", "replace"),
     ("/etc/systemd/system/felhom-agent.service", "felhom-agent.service", 0o644, "agent-unit", "replace"),
     ("/etc/systemd/system/felhom-agent-rollback.service", "felhom-agent-rollback.service", 0o644, "unit", "replace"),
     ("/etc/systemd/system/felhom-agent.service.d/felhom-agent-limits.conf", "felhom-agent-limits.conf", 0o644, "dropin", "replace"),
@@ -434,7 +473,8 @@ class Apply:
 
     def check_plan(self, plan):
         mode = plan.get("mode", "apply")
-        if mode not in ("apply", "inventory", "health", "facts", "live-restore-on", "bundle", "agent_update", "oom-check"):
+        if mode not in ("apply", "inventory", "health", "facts", "live-restore-on", "bundle", "agent_update", "oom-check") \
+                + KERNEL_MODES:
             raise Refused("R11", f"unknown mode {mode!r}")
         if mode == "agent_update":
             if plan.get("layer") != "host":
@@ -445,14 +485,18 @@ class Apply:
                 raise Refused("R11", "bundle is a host-layer mode")
             return mode, "host", 0, "bundle"
         layer = plan.get("layer")
-        if layer not in ("guest", "host", "docker", "pve"):
-            raise Refused("R12", f"layer {layer!r} is not guest, host, docker or pve")
+        if layer not in ("guest", "host", "docker", "pve", "kernel"):
+            raise Refused("R12", f"layer {layer!r} is not guest, host, docker, pve or kernel")
+        if (mode in KERNEL_MODES) != (layer == "kernel" and mode not in ("apply", "health")):
+            raise Refused("R11", f"mode {mode!r} does not fit layer {layer!r}")
         lane = plan.get("lane", "fast")
         if layer == "docker" and lane != "slow":
             raise Refused("R3", "the Docker engine is the slow lane (`11` §5.8); a fast-lane Docker plan is refused")
         if layer == "pve" and lane != "slow":
             raise Refused("R3", "the Proxmox packages are the slow lane (`11` §5.10); a fast-lane pve plan is refused")
-        if layer not in ("docker", "pve") and lane != "fast":
+        if layer == "kernel" and lane != "slow":
+            raise Refused("R3", "the kernel is the slow lane (`11` §5.11); a fast-lane kernel plan is refused")
+        if layer not in ("docker", "pve", "kernel") and lane != "fast":
             raise Refused("R3", f"the {layer} layer has no slow lane in this release (kernel, Proxmox: `11` §8 step 6)")
         if mode == "facts" and layer != "host":
             raise Refused("R11", "facts is a host-layer mode (it reads the host and the guest)")
@@ -463,7 +507,9 @@ class Apply:
         if plan.get("undo") and layer != "docker":  # the pve layer has no undo in this release (R-812 option A)
             raise Refused("R5", "an undo (downgrade) exists only for the Docker layer, inside a signed job")
         vmid = plan.get("vmid")
-        if not isinstance(vmid, int) or isinstance(vmid, bool) or vmid <= 0:
+        if layer == "kernel" and mode in KERNEL_MODES and mode != "kernel-reboot" and vmid == 0:
+            pass  # after a boot the guest may not run (that is what is judged); these modes never touch it
+        elif not isinstance(vmid, int) or isinstance(vmid, bool) or vmid <= 0:
             raise Refused("R11", f"vmid must be a positive integer, got {vmid!r}")
         rid = plan.get("release_id", "")
         if not isinstance(rid, str) or not re.match(r"^[A-Za-z0-9._:-]{1,80}$", rid):
@@ -471,19 +517,24 @@ class Apply:
         if plan.get("allow_new"):
             raise Refused("R6", "allow_new is a slow-lane field; the fast lane never adds a package")
         select = plan.get("select", "listed")
-        if select not in ("listed", "pending-fast", "pending-docker", "pending-pve"):
+        if select not in ("listed", "pending-fast", "pending-docker", "pending-pve", "pending-kernel"):
             raise Refused("R11", f"unknown select {select!r}")
         if (select == "pending-docker") != (layer == "docker" and select != "listed"):
             if select == "pending-docker" or layer == "docker":
                 raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
         if (select == "pending-pve") != (layer == "pve" and select != "listed"):
             raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
+        if (select == "pending-kernel") != (layer == "kernel" and select != "listed"):
+            raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
+        ek = plan.get("expect_kver")
+        if ek is not None and (layer != "kernel" or not isinstance(ek, str) or not KVER_RE.match(ek)):
+            raise Refused("R11", f"expect_kver {ek!r} is not a kernel version of the kernel layer")
         pk = plan.get("packages", [])
         if not isinstance(pk, list):
             raise Refused("R11", "packages must be a list")
         if mode == "apply" and select == "listed" and not pk:
             raise Refused("R11", "packages must be a non-empty list in apply mode (select listed)")
-        if select in ("pending-fast", "pending-docker", "pending-pve") and pk:
+        if select in ("pending-fast", "pending-docker", "pending-pve", "pending-kernel") and pk:
             raise Refused("R11", f"select {select} takes no package list")
         seen = set()
         for e in pk:
@@ -503,6 +554,13 @@ class Apply:
                 continue
             if n in DOCKER_NAMES:
                 raise Refused("R2", f"{n} is a Docker package — the slow lane (`11` §5.8), never in a {layer} plan")
+            if layer == "kernel":
+                if o != PVE_ORIGIN:
+                    raise Refused("R2", f"{n}: origin {o!r} is not {PVE_ORIGIN!r} (the kernel layer)")
+                if not (KERNEL_UPGRADE_RE.match(n) or KERNEL_IMAGE_RE.match(n)):
+                    raise Refused("R23", f"{n} is not a kernel package (a kernel image, the kernel meta-packages, "
+                                         f"proxmox-kernel-helper or pve-firmware)")
+                continue
             if layer == "pve":
                 if o != PVE_ORIGIN:
                     raise Refused("R2", f"{n}: origin {o!r} is not {PVE_ORIGIN!r} (the pve layer)")
@@ -759,6 +817,17 @@ class Apply:
             return v or "unknown"
         h = {"debian": first(["cat", "/etc/debian_version"]), "kernel_running": first(["uname", "-r"])}
         h["kernel_next_boot"], h["kernel_next_boot_source"] = self.kernel_next_boot()
+        try:
+            # the kernel lane (R-836): the default and the one-shot flag, read from grub.cfg and the ESP themselves
+            kv = Kernel(self, {}).view()
+            kv["setup_problems"] = Kernel(self, {}).setup_problems()
+            h["kernel_lane"] = kv
+            if kv.get("flag"):
+                h["kernel_next_boot"], h["kernel_next_boot_source"] = kv["flag"], "felhom one-shot flag (once; then the default)"
+            elif kv.get("default") not in (None, "unknown"):
+                h["kernel_next_boot"], h["kernel_next_boot_source"] = kv["default"], "grub.cfg default"
+        except Exception as e:  # never cost the System page its other facts
+            h["kernel_lane"] = {"error": str(e)[:200]}
         rc, out, _ = self.r.host(["apt-mark", "showhold"], 60)
         h["held"] = sorted(out.split()) if rc == 0 else None
         try:
@@ -817,8 +886,8 @@ class Apply:
 
     # ---------- target helpers ----------
     def x(self, argv, timeout=1800):
-        """Run in the TARGET layer: the guest via pct exec, or the host directly (host and pve)."""
-        if self.layer in ("host", "pve"):
+        """Run in the TARGET layer: the guest via pct exec, or the host directly (host, pve and kernel)."""
+        if self.layer in ("host", "pve", "kernel"):
             return self.r.host(argv, timeout)
         return self.r.guest(self.vmid, argv, timeout)  # guest and docker both live in the customer guest
 
@@ -913,7 +982,7 @@ class Apply:
     def restart_needed(self):
         """Processes still mapping deleted files, OUTSIDE containers (C11). Guest: outside docker; host: outside the
         LXC guests (the host's /proc shows guest processes too)."""
-        skip = RESTART_SKIP_CGROUP["host" if self.layer in ("host", "pve") else "guest"]
+        skip = RESTART_SKIP_CGROUP["host" if self.layer in ("host", "pve", "kernel") else "guest"]
         script = ('for p in /proc/[0-9]*; do grep -q "(deleted)" $p/maps 2>/dev/null || continue; '
                   'grep -q "%s" $p/cgroup 2>/dev/null && continue; echo "${p#/proc/} $(cat $p/comm 2>/dev/null)"; done' % skip)
         rc, out, _ = self.x(["sh", "-c", script], timeout=120)
@@ -987,8 +1056,12 @@ class Apply:
             return Bundle(self).from_plan(plan)
         if self.mode == "agent_update":
             return self.agent_update(plan)
-        if self.layer in ("host", "pve"):
+        if self.layer in ("host", "pve", "kernel"):
             self.check_appliance()
+        if self.layer == "kernel" and self.mode != "health":
+            # the kernel lane's own modes (R-836): most of them run while the guest is still starting after a boot, so
+            # the guest check is the stage's and the reboot's own (Kernel.run), not every mode's
+            return Kernel(self, plan).run()
         self.check_guest(self.vmid)
         log = self.r.log
         if self.mode == "live-restore-on":
@@ -1364,6 +1437,422 @@ class Apply:
         self.x(APT_ENV + ["apt-get", "-q", "update"], timeout=600)
 
 
+def _iso(t):
+    return time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime(t))
+
+
+def _parse_iso(s):
+    try:
+        return calendar.timegm(time.strptime(s, "%Y-%m-%dT%H:%M:%SZ"))
+    except (TypeError, ValueError):
+        return None
+
+
+class Kernel:
+    """The kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11). Refusal codes: R3 (authority), R4 (removal),
+    R6 (a package outside the step), R8 (space), R9 (locks), R12 (appliance), R20 (the box's boot setup cannot do a
+    one-shot), R21 (the crash guard is tripped or saw an unclean boot within its window), R22 (the step's phase does not
+    allow this mode), R23 (the kernel set is not one exact new kernel).
+
+    Modes (plan "mode", layer "kernel", lane "slow"):
+      apply          STAGE: install the kernel set, keep the GRUB default on the kernel the box runs, write the flag.
+                     Never reboots. select "pending-kernel" (ring 0, the root-owned mark) or "listed" (a signed
+                     os_kernel_step). expect_kver: the kernel the hub told the household about — any other is R23.
+      kernel-reboot  a STAGED step's reboot (the night leg, after the household was told): phase oneshot, then reboot.
+      kernel-boot    after a boot: what became of the step (judging | fell_back | self_reverted | revert_failed).
+      kernel-good    the one-shot boot was healthy: the new kernel becomes the GRUB default.
+      kernel-revert  the one-shot boot was NOT healthy: reboot ONCE into the old kernel (still the default).
+      kernel-cancel  drop a staged step: clear the flag (the package stays installed, the default never moved).
+      kernel-status  read only."""
+
+    def __init__(self, apply, plan):
+        self.a, self.r, self.plan = apply, apply.r, plan
+        self.report = apply.report
+        self.log = apply.r.log
+
+    # ---------- reading the box ----------
+    def running(self):
+        rc, out, _ = self.r.host(["uname", "-r"], 30)
+        v = out.strip() if rc == 0 else ""
+        return v if KVER_RE.match(v) else ""
+
+    def state(self):
+        try:
+            s = json.loads(self.r.read_file(KERNEL_STATE))
+            return s if isinstance(s, dict) else {}
+        except (OSError, ValueError):
+            return {}
+
+    def save_state(self, s):
+        s["updated_at"] = _iso(self.r.now())
+        self.r.put_file(KERNEL_STATE, (json.dumps(s, indent=2, sort_keys=True) + "\n").encode(), 0o644)
+
+    def flag(self):
+        """The one-shot flag: the kernel named, "" when the env block holds none, None when there is no env block."""
+        rc, out, _ = self.r.host(["grub-editenv", ONESHOT_ENV, "list"], 30)
+        if rc != 0:
+            return None
+        for l in out.splitlines():
+            if l.startswith("felhom_next="):
+                return l.split("=", 1)[1].strip()
+        return ""
+
+    def grub_cfg(self):
+        try:
+            return self.r.read_file(GRUB_CFG)
+        except OSError:
+            return ""
+
+    @staticmethod
+    def default_kver(cfg):
+        """The kernel grub.cfg boots by default (00_header's `set default=`), or "unknown"."""
+        m = re.search(r'^\s*set default="(?:gnulinux-advanced-[^>"]*>)?gnulinux-([0-9][^"]*?-pve)-advanced-[^"]*"', cfg, re.M)
+        return m.group(1) if m else "unknown"
+
+    @staticmethod
+    def entry_id(cfg, kver):
+        """The GRUB_DEFAULT value that names kver's normal entry, read from grub.cfg itself (10_linux's ids)."""
+        sub = re.search(r"\$menuentry_id_option '(gnulinux-advanced-[^']+)'", cfg)
+        m = re.search(r"\$menuentry_id_option '(gnulinux-" + re.escape(kver) + r"-advanced-[^']+)'", cfg)
+        if not m:
+            return None
+        return f"{sub.group(1)}>{m.group(1)}" if sub else m.group(1)
+
+    def setup_problems(self):
+        """R20: why this box cannot do a one-shot boot (empty = it can). Measured shape: UEFI, a vfat ESP at /boot/efi,
+        /boot on the root filesystem, GRUB with fat + loadenv, the bundle's two generators, no hand pin."""
+        why = []
+        if not self.r.lexists("/sys/firmware/efi"):
+            why.append("the box does not boot UEFI")
+        rc, out, _ = self.r.host(["findmnt", "-n", "-o", "FSTYPE", ESP_MOUNT], 30)
+        if rc != 0 or out.strip() != "vfat":
+            why.append(f"{ESP_MOUNT} is not a mounted vfat ESP ({out.strip() or 'not mounted'})")
+        rc, out, _ = self.r.host(["findmnt", "-n", "-o", "TARGET", "/boot"], 30)
+        if rc == 0 and out.strip():
+            why.append("/boot is a separate filesystem (the one-shot entries assume /boot on the root filesystem)")
+        for m in ("fat", "loadenv"):
+            if not self.r.lexists(f"/usr/lib/grub/x86_64-efi/{m}.mod"):
+                why.append(f"GRUB has no {m} module")
+        for p in (ONESHOT_SNIPPET, ONESHOT_ENTRIES):
+            if not self.r.lexists(p):
+                why.append(f"{p} is missing (the config bundle installs it)")
+        if self.r.lexists(KERNEL_PIN_FILE):
+            why.append("a kernel is pinned by hand (proxmox-boot-tool kernel pin) — the lane never fights it")
+        return why
+
+    def guard(self):
+        try:
+            return json.loads(self.r.read_file(CRASH_GUARD_STATE))
+        except (OSError, ValueError):
+            return None
+
+    def check_guard(self):
+        """R21: a kernel step only on a box whose crash guard is armed and saw no unclean boot within its window — so
+        the step's own reboots (clean), one crash and one self-revert (clean) can never reach the 3rd unclean boot that
+        leaves the box off (`11` §5.9). Pinned by test_felhom_crash_guard KernelStepCannotLeaveTheBoxOff."""
+        g = self.guard()
+        if not isinstance(g, dict):
+            raise Refused("R21", f"no crash guard state ({CRASH_GUARD_STATE}) — a kernel step needs the guard")
+        if g.get("tripped") or not g.get("armed"):
+            raise Refused("R21", "the crash guard is tripped — no kernel step until it re-arms")
+        if (g.get("unclean_boots_in_window") or 0) > 0:
+            raise Refused("R21", f"{g.get('unclean_boots_in_window')} unclean boot(s) within the guard's window — wait")
+
+    def view(self, st=None, cfg=None):
+        st = self.state() if st is None else st
+        cfg = self.grub_cfg() if cfg is None else cfg
+        return {"running": self.running() or "unknown", "default": self.default_kver(cfg), "flag": self.flag(),
+                "phase": st.get("phase", "none"), "from": st.get("from"), "to": st.get("to"),
+                "step_id": st.get("step_id"), "self_revert_used": bool(st.get("self_revert_used")), "vmid": st.get("vmid"),
+                "staged_at": st.get("staged_at"), "rebooted_at": st.get("rebooted_at"),
+                "result_at": st.get("result_at"), "reason": st.get("reason")}
+
+    # ---------- writing the box ----------
+    def write_default(self, kver):
+        """Pin the GRUB default to kver's normal entry, regenerate grub.cfg, and PROVE it (the default read back)."""
+        cfg = self.grub_cfg()
+        eid = self.entry_id(cfg, kver)
+        if not eid:
+            raise Refused("R20", f"grub.cfg has no normal entry for {kver}")
+        body = ("# felhom kernel lane (R-836, `11` §5.11) — written by felhom-os-apply; the kernel that booted healthily\n"
+                f'GRUB_DEFAULT="{eid}"\n')
+        self.r.put_file(KERNEL_DEFAULT_CFG, body.encode(), 0o644)
+        rc, out, err = self.r.host(["update-grub"], 300)
+        got = self.default_kver(self.grub_cfg())
+        if rc != 0 or got != kver:
+            raise Refused("R20", f"update-grub rc={rc}: the default reads {got}, not {kver}: {(out + err).strip()[-200:]}")
+        self.log(f"os-apply: KERNEL default = {kver} (proved from grub.cfg)")
+
+    def set_flag(self, kver):
+        self.r.host(["mkdir", "-p", os.path.dirname(ONESHOT_ENV)], 30)
+        if self.flag() is None:
+            rc, out, err = self.r.host(["grub-editenv", ONESHOT_ENV, "create"], 30)
+            if rc != 0:
+                raise Refused("R20", f"cannot create the one-shot env block on the ESP: {(out + err).strip()[-200:]}")
+        rc, out, err = self.r.host(["grub-editenv", ONESHOT_ENV, "set", f"felhom_next={kver}"], 30)
+        if rc != 0 or self.flag() != kver:
+            raise Refused("R20", f"the one-shot flag did not read back as {kver}: {(out + err).strip()[-200:]}")
+
+    def clear_flag(self):
+        if self.flag():
+            self.r.host(["grub-editenv", ONESHOT_ENV, "unset", "felhom_next"], 30)
+
+    def reboot(self, why):
+        self.log(f"os-apply: KERNEL REBOOT — {why}")
+        rc, out, err = self.r.host(["systemctl", "reboot"], 60)
+        self.report["reboot_rc"] = rc
+        if rc != 0:
+            self.report["failed"] = {"rc": 3, "step": "reboot", "reason": (out + err).strip()[-200:]}
+            return 3
+        return 0
+
+    # ---------- the modes ----------
+    def run(self):
+        mode = self.a.mode
+        self.report["kernel_mode"] = mode
+        if mode == "kernel-status":
+            v = self.view()
+            v["setup_problems"] = self.setup_problems()
+            self.report["kernel"] = v
+            return 0
+        fn = {"apply": self.stage, "kernel-reboot": self.reboot_staged, "kernel-boot": self.after_boot,
+              "kernel-good": self.good, "kernel-revert": self.revert, "kernel-cancel": self.cancel}[mode]
+        rc = fn()
+        self.report["kernel"] = self.view()
+        return rc
+
+    def phase_is(self, st, *phases):
+        if st.get("phase") not in phases:
+            raise Refused("R22", f"the kernel step is {st.get('phase', 'none')!r}, not {' or '.join(phases)} — "
+                                 f"{self.a.mode} does not apply")
+
+    def stage(self):
+        a = self.a
+        st = self.state()
+        if st.get("phase") in KERNEL_ACTIVE:
+            raise Refused("R22", f"a kernel step is already {st['phase']} ({st.get('from')} -> {st.get('to')})")
+        last = _parse_iso(st.get("staged_at"))
+        if last is not None and self.r.now() - last < KERNEL_MIN_GAP:
+            raise Refused("R22", "a kernel step was staged within the last 20 hours — never two in one night")
+        why = self.setup_problems()
+        if why:
+            raise Refused("R20", "; ".join(why))
+        self.check_guard()
+        a.check_guest(a.vmid)
+        who, _ = a.docker_authority(self.plan, op_name=KERNEL_OP)
+        self.report["authority"] = who
+        old = self.running()
+        if not old:
+            raise Refused("R20", "the running kernel is not a Proxmox kernel version")
+        self.log(f"os-apply: START release={self.plan.get('release_id')} layer=kernel lane=slow mode=apply "
+                 f"select={a.select} authority={who} running={old}")
+        if a.apt_lock_held():
+            raise Refused("R9", "another apt/dpkg holds the lock on the host")
+        self.report["health_before"] = a.health()
+        a.repair()
+        rc, out, err = a.x(APT_ENV + ["apt-get", "-q", "update"], timeout=600)
+        if rc != 0:
+            raise Refused("R7", f"apt-get update failed on the host: {(out + err).strip().splitlines()[-1:]}")
+        inst = a.installed()
+        if a.select == "pending-kernel":
+            _, pend, _, _ = a.simulate(["dist-upgrade"])
+            want = [(p["name"], p["to"]) for p in pend if p["from"] is not None and KERNEL_UPGRADE_RE.match(p["name"])
+                    and a.origin_name(p["origin"]) == {PVE_ORIGIN}]
+        else:
+            want = [(e["name"], e["version"]) for e in self.plan["packages"]]
+        # upgrades of installed names (never a downgrade), and at most the listed new kernel image
+        args, upg = [], {}
+        for n, v in want:
+            if n in inst:
+                if a.dpkg_cmp(v, "gt", inst[n]):
+                    upg[n] = v
+                    args.append(f"{n}={v}")
+            elif KERNEL_IMAGE_RE.match(n):
+                args.append(f"{n}={v}")
+            else:
+                raise Refused("R6", f"{n} is not installed and is not a kernel image")
+        if not args:
+            self.report["upgraded"], self.report["outcome_hint"] = [], "nothing"
+            self.log("os-apply: DONE rc=0 upgraded=0 (no pending kernel)")
+            return 0
+        rc, sim, remv, text = a.simulate(["install", "--no-install-recommends"] + args)
+        if rc != 0:
+            raise Refused("R7", "the simulation failed: " + (text.strip().splitlines()[-1] if text.strip() else ""))
+        if remv:
+            raise Refused("R4", f"the kernel step would remove {', '.join(remv[:5])}")
+        images = []
+        listed = dict(want)
+        for p in sim:
+            if a.origin_name(p["origin"]) != {PVE_ORIGIN}:
+                raise Refused("R2", f"{p['name']} would come from {p['origin']}, not {PVE_ORIGIN!r}")
+            m = KERNEL_IMAGE_RE.match(p["name"])
+            if p["from"] is None:
+                if not m:
+                    raise Refused("R6", f"the kernel step would add {p['name']}, which is not a kernel image")
+                if a.select == "listed" and listed.get(p["name"]) != p["to"]:
+                    raise Refused("R23", f"the kernel step would add {p['name']}={p['to']}, not the signed set")
+                images.append((m.group(1), p["to"]))
+                continue
+            if p["name"] not in upg or p["to"] != upg[p["name"]]:
+                raise Refused("R6", f"the kernel step would touch {p['name']} ({p['to']}), which is not in the step")
+            if not a.dpkg_cmp(p["to"], "gt", p["from"]):
+                raise Refused("R5", f"{p['name']} would be downgraded {p['from']} -> {p['to']}")
+        if len(images) > 1:
+            raise Refused("R23", f"the kernel step would add {len(images)} kernels — one at a time")
+        # the target kernel: the new image, else the series meta-package's version (its image is already installed)
+        if images:
+            new = images[0][0]
+            if images[0][1] + "-pve" != new:
+                raise Refused("R23", f"the image version {images[0][1]} does not name the kernel {new}")
+        else:
+            metas = [(n, v) for n, v in upg.items() if re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n)]
+            if len(metas) != 1:
+                self.report["upgraded"], self.report["outcome_hint"] = [], "nothing"
+                self.log("os-apply: DONE rc=0 upgraded=0 (the pending set names no kernel to boot)")
+                return 0
+            new = metas[0][1] + "-pve"
+        if not KVER_RE.match(new) or not a.dpkg_cmp(new[:-4], "gt", old[:-4]):
+            raise Refused("R23", f"the kernel {new} is not newer than the running {old}")
+        ek = self.plan.get("expect_kver")
+        if ek and ek != new:
+            raise Refused("R23", f"the step would boot {new}, but the household was told about {ek}")
+        need = a.download_bytes(["install", "--no-install-recommends"] + args)
+        free = a.free_bytes()
+        if free >= 0 and free < max(MIN_FREE, 3 * need):
+            raise Refused("R8", f"free space {free} B is below max(500 MB, 3 x download {need} B)")
+        # 1. the default = the kernel the box RUNS (it booted healthily), proved from grub.cfg BEFORE the install
+        default_before = self.default_kver(self.grub_cfg())
+        self.write_default(old)
+        # 2. install (the kernel's own postinst runs update-grub; our default file keeps the default on `old`)
+        t0 = time.time()
+        rc, out, err = a.x(APT_ENV + ["apt-get", "-y", "-q"] + DPKG_OPTS + ["install", "--no-install-recommends"] + args)
+        a.x(["apt-get", "clean"])
+        if rc != 0:
+            _, aud, _ = a.x(["dpkg", "--audit"])
+            self.report["failed"] = {"rc": rc, "step": "install", "dpkg_audit": (aud.strip().splitlines() or ["clean"])[0],
+                                     "tail": (out + err).strip().splitlines()[-3:]}
+            self.log(f"os-apply: FAILED rc={rc} step=install (the default stays {old}; no flag written)")
+            return 3
+        self.report["upgraded"] = [{"name": x.split("=", 1)[0], "version": x.split("=", 1)[1]} for x in args]
+        self.report["seconds"] = round(time.time() - t0, 1)
+        # 3. prove: the image is there, the default is still `old`, the one-shot entry for `new` exists
+        cfg = self.grub_cfg()
+        if f"felhom-oneshot-{new}" not in cfg or self.default_kver(cfg) != old:
+            self.r.host(["update-grub"], 300)
+            cfg = self.grub_cfg()
+        for f in (f"/boot/vmlinuz-{new}", f"/boot/initrd.img-{new}"):
+            if not self.r.lexists(f):
+                self.report["failed"] = {"rc": 3, "step": "verify", "reason": f"{f} is missing after the install"}
+                return 3
+        if f"felhom-oneshot-{new}" not in cfg or "felhom_next" not in cfg:
+            self.report["failed"] = {"rc": 3, "step": "verify", "reason": f"grub.cfg has no one-shot entry for {new}"}
+            return 3
+        if self.default_kver(cfg) != old:
+            self.report["failed"] = {"rc": 3, "step": "verify",
+                                     "reason": f"the install moved the default to {self.default_kver(cfg)} — no flag written"}
+            return 3
+        # 4. the flag — the ONLY thing that makes the next boot use `new`, and only once
+        self.set_flag(new)
+        self.save_state({"phase": "staged", "step_id": self.plan.get("release_id"), "from": old, "to": new, "vmid": a.vmid,
+                         "staged_at": _iso(self.r.now()), "authority": who, "default_before": default_before,
+                         "packages": self.report["upgraded"], "self_revert_used": False})
+        self.report["reboot_needed"] = True
+        self.log(f"os-apply: KERNEL STAGED {old} -> {new} (default {old}, one-shot flag {new}); upgraded={len(args)} "
+                 f"seconds={self.report['seconds']}")
+        return 0
+
+    def reboot_staged(self):
+        st = self.state()
+        self.phase_is(st, "staged")
+        if self.flag() != st.get("to"):
+            raise Refused("R22", f"the one-shot flag reads {self.flag()!r}, not {st.get('to')!r}")
+        if self.running() != st.get("from"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the step's old kernel {st.get('from')!r}")
+        cfg = self.grub_cfg()
+        if self.default_kver(cfg) != st["from"] or f"felhom-oneshot-{st['to']}" not in cfg:
+            raise Refused("R20", "grub.cfg no longer keeps the old default with a one-shot entry for the new kernel")
+        if self.setup_problems():
+            raise Refused("R20", "; ".join(self.setup_problems()))
+        self.check_guard()
+        self.a.check_guest(self.a.vmid)
+        st["health_before"] = self.a.health()
+        st["phase"], st["rebooted_at"] = "oneshot", _iso(self.r.now())
+        self.save_state(st)
+        return self.reboot(f"one-shot boot of {st['to']} (the default stays {st['from']})")
+
+    def after_boot(self):
+        st = self.state()
+        ph, run = st.get("phase"), self.running()
+        old, new = st.get("from"), st.get("to")
+        event = "none"
+        if ph in ("oneshot", "staged", "judging") and run == new and new:
+            if ph != "judging":
+                st["phase"], st["judging_since"], event = "judging", _iso(self.r.now()), "judging"
+            else:
+                event = "judging"
+        elif ph in ("oneshot", "judging") and run == old:
+            # the new kernel did not come up, or crashed: GRUB already booted the default (the old kernel)
+            self.clear_flag()
+            st["phase"], st["result_at"], event = "fell_back", _iso(self.r.now()), "fell_back"
+            st["reason"] = "the box came back on the old kernel by itself (the new one did not boot, or crashed)"
+        elif ph == "reverting" and run == old:
+            st["phase"], st["result_at"], event = "self_reverted", _iso(self.r.now()), "self_reverted"
+        elif ph == "reverting" and run == new:
+            st["phase"], st["result_at"], event = "revert_failed", _iso(self.r.now()), "revert_failed"
+            st["reason"] = "the self-revert came back on the NEW kernel — never retried (one self-revert per step)"
+        if event not in ("none",) and st.get("phase") != ph:
+            self.save_state(st)
+            self.log(f"os-apply: KERNEL AFTER-BOOT {ph} -> {st['phase']} running={run} ({old} -> {new})")
+        self.report["kernel_event"] = event
+        if event == "judging":
+            self.report["health_before"] = st.get("health_before")  # the agent judges the boot against it
+        return 0
+
+    def good(self):
+        st = self.state()
+        self.phase_is(st, "judging")
+        if self.running() != st.get("to"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the new kernel {st.get('to')!r}")
+        try:
+            self.write_default(st["to"])
+        except Refused:
+            # put the old default back — the box must never be left without a proved default
+            self.write_default(st["from"])
+            raise
+        self.clear_flag()
+        st["phase"], st["result_at"] = "good", _iso(self.r.now())
+        self.save_state(st)
+        self.log(f"os-apply: KERNEL GOOD {st['to']} is the default now (was {st['from']})")
+        return 0
+
+    def revert(self):
+        st = self.state()
+        self.phase_is(st, "judging")
+        if st.get("self_revert_used"):
+            raise Refused("R22", "this kernel step already used its one self-revert")
+        if self.running() != st.get("to"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the new kernel {st.get('to')!r}")
+        self.clear_flag()
+        cfg = self.grub_cfg()
+        if self.default_kver(cfg) != st.get("from"):
+            raise Refused("R20", f"the GRUB default reads {self.default_kver(cfg)}, not the old {st.get('from')} — "
+                                 f"no self-revert into an unknown kernel")
+        reason = self.plan.get("reason")
+        st["reason"] = reason[:300] if isinstance(reason, str) else "the one-shot boot was not healthy"
+        st["self_revert_used"], st["phase"], st["reverted_at"] = True, "reverting", _iso(self.r.now())
+        self.save_state(st)
+        return self.reboot(f"self-revert to {st['from']}: {st['reason']}")
+
+    def cancel(self):
+        st = self.state()
+        self.phase_is(st, "staged")
+        self.clear_flag()
+        st["phase"], st["result_at"], st["reason"] = "cancelled", _iso(self.r.now()), "cancelled before the reboot"
+        self.save_state(st)
+        self.log(f"os-apply: KERNEL CANCELLED {st.get('to')} (installed, never the default; flag cleared)")
+        return 0
+
+
 class Bundle:
     """The config bundle (R-840, `11` §5.4.2): every root-owned file the installer's step 5 writes, installed as ONE
     signed unit. Every check runs before the first write; a failed write or a failed self-check puts every previous

configs/felhom-vzdump-partial-clean

@@ -0,0 +1,99 @@
+#!/bin/bash
+# felhom-vzdump-partial-clean — remove ONE dead, half-written vzdump backup (R-1006). The only delete the agent's
+# sudoers allows for backup files. Installed as /usr/local/sbin/felhom-vzdump-partial-clean (config bundle).
+#
+#   felhom-vzdump-partial-clean <storage> <vmid> <name>
+#
+# A power cut during the night backup leaves `vzdump-lxc-<vmid>-<date>.tar.dat` (+ its `.tmp/` directory) on the
+# storage; nothing removes it, every later backup is then skipped „not enough space", and a full host root breaks
+# LVM's own metadata writes (power-cut-fixes-2026-10-14 C4). This helper removes such a leftover — and NOTHING else.
+# It trusts nothing the agent says; every rule is checked here, as root, and any doubt REFUSES (exit 1):
+#   1. the arguments: a storage id, a vmid, and a name that is exactly
+#      vzdump-(lxc|qemu)-<THAT vmid>-YYYY_MM_DD-HH_MM_SS.(tar.dat|vma.dat|tmp) — never a finished archive
+#      (.tar.zst, .vma.zst, …), never a .log/.notes, never another vmid;
+#   2. the storage: its section in /etc/pve/storage.cfg is `dir: <storage>` with a `path`; the target is
+#      <path>/dump/<name>, not a symlink, and its real directory IS <path>/dump;
+#   3. not in use: no vzdump runs on the host at all (a task `…:vzdump:…` or a `vzdump` command — a job for several
+#      guests carries no vmid in its task name), and no
+#      process holds the target (or, for the .tmp directory, anything under it) open or as its working directory
+#      (C2: after a killed worker, tar and zstd kept writing into the .tar.dat for 4 min 40 s, none named „vzdump");
+#   4. dead: last modified before this boot (`btime` in /proc/stat), or untouched for at least QUIET_S seconds.
+# Prints one line on success: „removed <name> <bytes> B (<why>)". Pinned by configs/test_felhom_vzdump_partial_clean.py.
+set -u
+STORAGE_CFG=/etc/pve/storage.cfg
+PROC=/proc
+QUIET_S=120
+
+die() { echo "felhom-vzdump-partial-clean: REFUSED: $*" >&2; exit 1; }
+
+storage_path() { # $1 storage id → prints the dir storage's path, or nothing
+	awk -v want="$1" '
+		/^[a-z]+:[ \t]/ { split($0, h, /:[ \t]+/); type = h[1]; id = h[2]; sub(/[ \t]+$/, "", id); in_s = (id == want); next }
+		in_s && /^[ \t]+path[ \t]/ { if (type == "dir") { sub(/^[ \t]+path[ \t]+/, ""); sub(/[ \t]+$/, ""); print; exit } }
+	' "$STORAGE_CFG"
+}
+
+storage_type() {
+	awk -v want="$1" '/^[a-z]+:[ \t]/ { split($0, h, /:[ \t]+/); id = h[2]; sub(/[ \t]+$/, "", id); if (id == want) { print h[1]; exit } }' "$STORAGE_CFG"
+}
+
+boot_time() { awk '$1 == "btime" { print $2 }' "$PROC/stat"; }
+
+newest_mtime() { # a file's mtime, or the newest mtime of anything in a directory (the dir itself included)
+	if [[ -d "$1" ]]; then find "$1" -xdev -printf '%T@\n' 2>/dev/null | sort -n | tail -1 | cut -d. -f1
+	else stat -c %Y "$1"; fi
+}
+
+busy_reason() { # $1 vmid, $2 target → prints why it is in use, or nothing
+	local vmid=$1 target=$2 p link cmd
+	for p in "$PROC"/[0-9]*; do
+		[[ -r "$p/cmdline" ]] || continue
+		cmd=$(tr '\0' ' ' < "$p/cmdline" 2>/dev/null)
+		# ANY vzdump on the host refuses: a job for several guests runs as `task UPID:…:vzdump::…` (no vmid in it), and
+		# its tar may be between this guest's files. Waiting costs one backup run; deleting a live one costs the backup.
+		if [[ "$cmd" == *":vzdump:"* ]] || [[ "$cmd" =~ (^|/)vzdump([[:space:]]|$) ]]; then
+			echo "a vzdump runs on this host (pid ${p##*/})"; return
+		fi
+		for link in "$p/cwd" "$p"/fd/*; do
+			local to
+			to=$(readlink "$link" 2>/dev/null) || continue
+			if [[ "$to" == "$target" || "$to" == "$target/"* ]]; then
+				echo "pid ${p##*/} has it open"; return
+			fi
+		done
+	done
+}
+
+main() {
+	local storage=${1:-} vmid=${2:-} name=${3:-}
+	[[ $# -eq 3 ]] || die "usage: felhom-vzdump-partial-clean <storage> <vmid> <name>"
+	[[ "$storage" =~ ^[A-Za-z][A-Za-z0-9_-]{0,63}$ ]] || die "bad storage id"
+	[[ "$vmid" =~ ^[1-9][0-9]{2,8}$ ]] || die "bad vmid"
+	[[ "$name" =~ ^vzdump-(lxc|qemu)-${vmid}-[0-9]{4}_[0-9]{2}_[0-9]{2}-[0-9]{2}_[0-9]{2}_[0-9]{2}\.(tar\.dat|vma\.dat|tmp)$ ]] \
+		|| die "name is not a half-written vzdump of guest $vmid: $name"
+	[[ "$(storage_type "$storage")" == "dir" ]] || die "storage $storage is not a dir storage"
+	local path; path=$(storage_path "$storage")
+	[[ "$path" == /* ]] || die "storage $storage has no path"
+	local dump="$path/dump" target="$path/dump/$name"
+	[[ -e "$target" ]] || die "no such entry: $target"
+	[[ ! -L "$target" ]] || die "a symlink: $target"
+	[[ "$(realpath -e "$dump")" == "$(realpath -e "$(dirname "$target")")" ]] || die "not directly in $dump"
+	if [[ "$name" == *.tmp ]]; then [[ -d "$target" ]] || die ".tmp is not a directory"
+	else [[ -f "$target" ]] || die "not a regular file"; fi
+	local busy; busy=$(busy_reason "$vmid" "$target")
+	[[ -z "$busy" ]] || die "in use: $busy"
+	local bt mt now why
+	bt=$(boot_time); mt=$(newest_mtime "$target"); now=$(date +%s)
+	[[ "$bt" =~ ^[0-9]+$ && "$mt" =~ ^[0-9]+$ ]] || die "cannot read the boot time or the modification time"
+	if (( mt < bt )); then why="written before this boot"
+	elif (( now - mt >= QUIET_S )); then why="untouched for $(( now - mt )) s, no vzdump for $vmid, nothing holds it"
+	else die "modified $(( now - mt )) s ago — may still be written"; fi
+	local size; size=$(du -sb "$target" 2>/dev/null | cut -f1)
+	if [[ -d "$target" ]]; then rm -rf --one-file-system -- "$target"; else rm -f -- "$target"; fi
+	[[ ! -e "$target" ]] || die "remove failed: $target"
+	echo "removed $name ${size:-?} B ($why)"
+}
+
+if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
+	main "$@"
+fi

configs/test_felhom_crash_guard.py

@@ -139,5 +139,62 @@ class Guard(unittest.TestCase):
         self.assertEqual(mode, 0o644)
 
 
+class KernelStepCannotLeaveTheBoxOff(unittest.TestCase):
+    """R-836 / `11` §5.11 Part B 4: a kernel step's planned reboot, one crash and one self-revert cannot add up to the
+    box staying off. The wrapper starts a step only when the guard is armed with NO unclean boot in its window
+    (felhom-os-apply Kernel.check_guard, R21); the planned reboot and the self-revert are orderly (`systemctl reboot` —
+    the clean-stop marker); so the step adds at most ONE unclean boot, and the box stays off only after the LIMIT-th
+    (3rd) within the hour. Red-proof: audits/kernel-lane-2026-10-07/A/redproof.txt."""
+
+    def setUp(self):
+        self.d = tempfile.TemporaryDirectory()
+        self.e = FakeEnv(self.d.name)
+        cg.main(["x", "boot"], self.e)
+        s = self.e.state()
+        self.assertTrue(s["armed"])
+        self.assertEqual(s["unclean_boots_in_window"], 0, "the wrapper's precondition (R21)")
+
+    def tearDown(self):
+        self.d.cleanup()
+
+    def planned(self, minutes):
+        cg.main(["x", "clean-stop"], self.e)
+        self.e.t += minutes * 60
+        cg.main(["x", "boot"], self.e)
+
+    def crash(self, minutes):
+        self.e.t += minutes * 60
+        cg.main(["x", "boot"], self.e)
+
+    def test_planned_reboot_one_crash_one_self_revert(self):
+        self.planned(2)      # the step's one-shot reboot (orderly)
+        self.crash(3)        # the new kernel crashes after the guard ran; the box restarts (panic=10)
+        self.planned(2)      # the self-revert (orderly)
+        s = self.e.state()
+        self.assertFalse(s["tripped"], s)
+        self.assertTrue(s["armed"])
+        self.assertEqual(self.e.panic(), 10, "the box still restarts after a crash")
+        self.assertEqual(s["unclean_boots_in_window"], 1, "the step added exactly one unclean boot")
+
+    def test_a_panic_before_userspace_is_not_even_counted(self):
+        # the one-shot kernel panics before the guard's unit runs (measured: rdinit= and init= missing): the planned
+        # reboot's clean-stop marker is still there when the old kernel boots, so this boot counts as clean.
+        cg.main(["x", "clean-stop"], self.e)
+        self.e.t += 120      # the panicking boot: no userspace, the guard never ran
+        cg.main(["x", "boot"], self.e)
+        s = self.e.state()
+        self.assertEqual(s["unclean_boots_in_window"], 0, s)
+        self.assertEqual(self.e.panic(), 10)
+
+    def test_the_box_stays_off_only_after_two_more_crashes_than_the_step_makes(self):
+        self.planned(2)
+        self.crash(3)        # the step's one crash
+        self.planned(2)      # the self-revert
+        self.crash(5)        # an UNRELATED crash within the hour: the guard trips (the 3rd would leave it off)
+        s = self.e.state()
+        self.assertTrue(s["tripped"])
+        self.assertEqual(s["unclean_boots_in_window"], 2, "two unclean boots: one from the step, one not")
+
+
 if __name__ == "__main__":
     unittest.main()

configs/test_felhom_internal_place.py

@@ -0,0 +1,255 @@
+#!/usr/bin/env python3
+"""Tests for configs/felhom-internal-place (felhom.eu architecture/16 §5, §7 — sizes ruled 2026-10-16).
+
+The helper is run for real under bash; `lvs`, `lvcreate`, `blkid`, `mkfs.ext4` and `stat` are PATH stubs that read and
+write one JSON state file, so nothing on this machine is touched. Every refusal has a positive control: the same setup
+without the one condition goes through — so a test cannot pass because the helper refuses everything.
+Run: python3 configs/test_felhom_internal_place.py   (also run by the Go suite, internal/internalplace)
+"""
+import json, os, pathlib, stat, subprocess, tempfile, unittest
+
+HELPER = pathlib.Path(__file__).resolve().parent / "felhom-internal-place"
+GIB = 1 << 30
+
+STUB_LVS = r'''#!/usr/bin/env python3
+import json, os, sys
+st = json.load(open(os.environ["IP_STATE"]))
+if st.get("lvs_fail_listing") and "lv_name,pool_lv,lv_size" in sys.argv: sys.exit(5)
+args = [a for a in sys.argv[1:] if not a.startswith("-") and a not in ("b",)]
+fields = sys.argv[sys.argv.index("-o") + 1].split(",")
+target = args[-1]
+listing = target == st["vg"]
+for lv in st["lvs"]:
+    full = st["vg"] + "/" + lv["name"]
+    if listing and st.get("hide_pool_in_listing") and lv.get("pool", "") == "":
+        continue   # a listing that silently lost the pool row (the pool's own size stays readable)
+    if listing or target == full:
+        row = {"lv_name": lv["name"], "pool_lv": lv.get("pool", ""), "lv_size": str(lv["size"])}
+        print("  " + " ".join(row[f] for f in fields))
+'''
+STUB_LVCREATE = r'''#!/usr/bin/env python3
+import json, os, sys
+p = os.environ["IP_STATE"]; st = json.load(open(p))
+a = sys.argv[1:]
+size = int(a[a.index("-V") + 1].rstrip("G")) * (1 << 30)
+vg, pool = a[a.index("-T") + 1].split("/")
+st["lvs"].append({"name": a[a.index("-n") + 1], "pool": pool, "size": size, "active": True})
+st.setdefault("calls", []).append("lvcreate " + " ".join(a))
+if st.get("dirty_new"): st["fs"]["felhom-belso"] = {"TYPE": "", "RAW": "junk"}
+json.dump(st, open(p, "w"))
+'''
+STUB_BLKID = r'''#!/usr/bin/env python3
+# like blkid -p: exit 0 when something is found, 2 when nothing is; st["blkid_rc"] forces an error exit
+import json, os, sys
+st = json.load(open(os.environ["IP_STATE"]))
+if st.get("blkid_rc"): sys.exit(st["blkid_rc"])
+fs = st["fs"].get(os.path.basename(sys.argv[-1]), {})
+if "-s" in sys.argv:
+    v = fs.get(sys.argv[sys.argv.index("-s") + 1], "")
+    if v: print(v)
+    sys.exit(0 if v else 2)
+vals = [fs.get(k, "") for k in ("TYPE", "LABEL", "UUID", "RAW") if fs.get(k)]
+if vals: print("\n".join(vals))
+sys.exit(0 if vals else 2)
+'''
+STUB_MKFS = r'''#!/usr/bin/env python3
+import json, os, sys
+p = os.environ["IP_STATE"]; st = json.load(open(p))
+dev = os.path.basename(sys.argv[-1])
+st["fs"][dev] = {"TYPE": "ext4", "LABEL": sys.argv[sys.argv.index("-L") + 1], "UUID": "0b6e4c5a-1d2e-4f3a-9b8c-7d6e5f4a3b2c"}
+st.setdefault("calls", []).append("mkfs.ext4 " + " ".join(sys.argv[1:]))
+json.dump(st, open(p, "w"))
+'''
+STUB_STAT = r'''#!/usr/bin/env python3
+import json, os, sys
+st = json.load(open(os.environ["IP_STATE"]))
+name = os.path.basename(sys.argv[-1])
+if any(lv["name"] == name and lv.get("active", True) for lv in st["lvs"]): print("block special file")
+else: sys.exit(1)
+'''
+
+CFG = "dir: local\n\tpath /var/lib/vz\n\tcontent iso,backup\n\nlvmthin: local-lvm\n\tthinpool data\n\tvgname pve\n\tcontent rootdir,images\n"
+
+
+class Box:
+    def __init__(self, pool_gib, lvs=(), fs=None, cfg=CFG, **extra):
+        self.t = tempfile.TemporaryDirectory()
+        r = pathlib.Path(self.t.name)
+        self.bin = r / "bin"; self.bin.mkdir()
+        for name, body in (("lvs", STUB_LVS), ("lvcreate", STUB_LVCREATE), ("blkid", STUB_BLKID),
+                           ("mkfs.ext4", STUB_MKFS), ("stat", STUB_STAT)):
+            f = self.bin / name; f.write_text(body); f.chmod(0o755)
+        self.cfg = r / "storage.cfg"; self.cfg.write_text(cfg)
+        self.state = r / "state.json"
+        st = {"vg": "pve", "lvs": [{"name": "data", "pool": "", "size": pool_gib * GIB}] + [dict(l) for l in lvs],
+              "fs": fs or {}}
+        st.update(extra)
+        self.state.write_text(json.dumps(st))
+
+    def run(self, *args):
+        env = {"PATH": f"{self.bin}:/usr/bin:/bin", "IP_STATE": str(self.state), "FELHOM_STORAGE_CFG": str(self.cfg)}
+        p = subprocess.run(["bash", str(HELPER), *args], env=env, capture_output=True, text=True)
+        return p.returncode, p.stdout.strip(), p.stderr.strip()
+
+    def st(self):
+        return json.loads(self.state.read_text())
+
+    def calls(self):
+        return self.st().get("calls", [])
+
+    def close(self):
+        self.t.cleanup()
+
+
+def thin(name, gib, pool="data"):
+    return {"name": name, "pool": pool, "size": gib * GIB}
+
+
+class Sizes(unittest.TestCase):
+    """The operator's table (SPACE-CHECK §4, ruled 2026-10-16), as the helper computes it on a fresh box."""
+
+    def plan(self, pool, planned, lvs=()):
+        b = Box(pool, lvs)
+        try:
+            rc, out, err = b.run("plan", str(planned))
+            self.assertEqual(rc, 0, err)
+            self.assertEqual(b.calls(), [], "plan must change nothing")
+            return dict(kv.split("=") for kv in out.split()[1:])
+        finally:
+            b.close()
+
+    def test_the_ruled_table(self):
+        # disk → pool (GiB), data volume (planned = 32 + mp0), expected internal
+        for pool, mp0, reserve, internal in ((140, 50, 16, 42), (349, 100, 34, 183), (800, 130, 48, 590), (1720, 130, 48, 1510)):
+            got = self.plan(pool, 32 + mp0)
+            self.assertEqual((int(got["reserve"]), int(got["internal"])), (reserve, internal), (pool, got))
+
+    def test_promised_volumes_count_but_vzdump_snapshots_and_other_pools_do_not(self):
+        got = self.plan(349, 0, [thin("vm-9201-disk-0", 32), thin("vm-9201-disk-1", 250),
+                                 thin("snap_vm-9201-disk-1_vzdump", 250), thin("vm-500-disk-0", 40, pool="other")])
+        self.assertEqual((int(got["promised"]), int(got["internal"])), (282, 33), got)
+
+
+class Create(unittest.TestCase):
+    def test_a_fresh_box_gets_the_place(self):
+        b = Box(349)
+        try:
+            rc, out, err = b.run("create", "132")
+            self.assertEqual(rc, 0, err)
+            self.assertRegex(out, r"^created uuid=[0-9a-f-]{36} gib=183$")
+            self.assertEqual(len([c for c in b.calls() if c.startswith("lvcreate")]), 1)
+            self.assertIn("-V 183G -T pve/data -n felhom-belso", b.calls()[0])
+            self.assertIn("-L felhom-belso", b.calls()[1])
+        finally:
+            b.close()
+
+    def test_too_little_space_makes_nothing(self):
+        b = Box(53)   # demo-hp's 128 GB disk
+        try:
+            rc, out, err = b.run("create", str(32 + 50))
+            self.assertEqual(rc, 0, err)
+            self.assertTrue(out.startswith("skipped "), out)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+
+    def test_an_existing_place_is_found_never_formatted(self):
+        fs = {"felhom-belso": {"TYPE": "ext4", "LABEL": "felhom-belso", "UUID": "11111111-2222-3333-4444-555555555555"}}
+        b = Box(349, [thin("felhom-belso", 183)], fs)
+        try:
+            rc, out, err = b.run("create", "0")
+            self.assertEqual(rc, 0, err)
+            self.assertEqual(out, "existing uuid=11111111-2222-3333-4444-555555555555 gib=183")
+            self.assertEqual(b.calls(), [], "an existing place must never be created or formatted again")
+        finally:
+            b.close()
+
+    def test_a_foreign_filesystem_on_the_name_is_refused(self):
+        # positive control: test_an_existing_place_is_found_never_formatted (same LV, Felhom's label) goes through
+        for fs in ({"TYPE": "xfs", "LABEL": "felhom-belso", "UUID": "x"}, {"TYPE": "ext4", "LABEL": "films", "UUID": "y"}):
+            b = Box(349, [thin("felhom-belso", 183)], {"felhom-belso": fs})
+            try:
+                rc, out, err = b.run("create", "0")
+                self.assertEqual(rc, 1, (fs, out))
+                self.assertIn("REFUSED", err)
+                self.assertEqual(b.calls(), [], fs)
+            finally:
+                b.close()
+
+    def test_a_crash_between_lvcreate_and_mkfs_is_finished(self):
+        b = Box(349, [thin("felhom-belso", 183)], {})
+        try:
+            rc, out, err = b.run("create", "0")
+            self.assertEqual(rc, 0, err)
+            self.assertRegex(out, r"^formatted uuid=")
+            self.assertEqual([c.split()[0] for c in b.calls()], ["mkfs.ext4"])
+        finally:
+            b.close()
+
+    def test_an_unnamed_signature_is_refused(self):
+        b = Box(349, [thin("felhom-belso", 183)], {"felhom-belso": {"RAW": "something"}})
+        try:
+            rc, out, err = b.run("create", "0")
+            self.assertEqual(rc, 1, out)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+
+    def test_a_new_volume_that_is_not_empty_is_not_formatted(self):
+        b = Box(349, dirty_new=True)
+        try:
+            rc, out, err = b.run("create", "132")
+            self.assertEqual(rc, 1, out)
+            self.assertNotIn("mkfs", " ".join(b.calls()))
+        finally:
+            b.close()
+
+    def test_bad_arguments_and_no_local_lvm_are_refused(self):
+        b = Box(349, cfg="dir: local\n\tpath /var/lib/vz\n")
+        try:
+            self.assertEqual(b.run("create", "0")[0], 1)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+        b = Box(349)
+        try:
+            for args in (("create", "-1"), ("create", "1x"), ("wipe", "0"), ("create",)):
+                self.assertEqual(b.run(*args)[0], 1, args)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+
+
+class FailsClosed(unittest.TestCase):
+    """A read that fails must never read as „empty" or „nothing promised". Positive control: Create (same setups)."""
+
+    def test_a_failed_volume_listing_creates_nothing(self):
+        b = Box(349, lvs_fail_listing=True)
+        try:
+            rc, out, err = b.run("create", "132")
+            self.assertEqual(rc, 1, out)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+
+    def test_a_listing_without_the_pool_creates_nothing(self):
+        b = Box(349, [thin("vm-9201-disk-1", 250)], hide_pool_in_listing=True)
+        try:
+            self.assertEqual(b.run("create", "132")[0], 1)
+            self.assertEqual(b.calls(), [])
+        finally:
+            b.close()
+
+    def test_a_blkid_error_never_reads_as_empty(self):
+        for setup in ({"lvs": [thin("felhom-belso", 183)], "fs": {}}, {}):
+            b = Box(349, **({"lvs": setup["lvs"], "fs": setup["fs"]} if setup else {}), blkid_rc=4)
+            try:
+                rc, out, err = b.run("create", "0" if setup else "132")
+                self.assertEqual(rc, 1, (setup, out))
+                self.assertNotIn("mkfs", " ".join(b.calls()), setup)
+            finally:
+                b.close()
+
+
+if __name__ == "__main__":
+    unittest.main()

configs/test_felhom_mkfs_guarded.py

@@ -0,0 +1,145 @@
+#!/usr/bin/env python3
+"""Tests for configs/felhom-mkfs-guarded.sh — the ONLY mkfs path the agent's sudoers permits.
+
+First tests of this wrapper (agent v0.158.0), written for partitions as places (felhom.eu architecture/16 §6). Every
+mount of every node of the disk outside /mnt/felhom-drives refuses — INCLUDING a sibling that is Felhom's own drive
+(its raw /mnt/<name> mount): the agent can make that corroborating mount itself, so the root wrapper must not trust
+it (security review of 912f7c1). An unlistable disk refuses.
+
+HOW IT RUNS ANYWHERE: the wrapper is copied with five literal host paths replaced (each replacement is asserted, so a
+drifted wrapper fails here instead of silently testing nothing): /proc/mounts → a fake mount table, the block-device
+test → true (no real /dev nodes here), the pvs candidates → a stub, /sys/block → a fake tree, the mkfs binaries → a
+recorder. `lsblk` is a PATH stub answering the three calls the wrapper makes from one JSON disk description.
+Every refusal has a positive control (the same disk without the one condition is formatted).
+Run: python3 configs/test_felhom_mkfs_guarded.py   (also run by the Go suite, internal/storage)
+"""
+import json, os, pathlib, subprocess, tempfile, unittest
+
+WRAPPER = pathlib.Path(__file__).resolve().parent / "felhom-mkfs-guarded.sh"
+
+STUB_LSBLK = r'''#!/usr/bin/env python3
+import json, os, sys
+st = json.load(open(os.environ["MG_STATE"]))
+a = sys.argv[1:]; dev = a[-1]
+nodes = st["nodes"]   # [{"name": "/dev/sdb", "pk": "", "fstype": ""}, ...]
+if a[0] == "-ndo" and a[1] == "PKNAME":
+    for n in nodes:
+        if n["name"] == dev and n.get("pk"): print(n["pk"])
+elif a[0] == "-nrpo" and a[1] == "NAME":
+    if not st.get("lsblk_empty"):
+        for n in nodes: print(n["name"])
+elif a[0] == "-nro" and a[1] == "FSTYPE":
+    for n in nodes: print(n.get("fstype", ""))
+elif a[0] == "-nro" and a[1] == "MOUNTPOINT":   # the pre-v0.158.0 wrapper's call: one mountpoint per node, like lsblk
+    mt = [l.split()[:2] for l in open(os.environ["MG_MOUNTS"]) if l.strip()]
+    for n in nodes:
+        mps = [m for d, m in mt if d == n["name"]]
+        print(mps[0] if mps else "")
+'''
+STUB_MKFS = '#!/bin/sh\necho "$0 $*" >> "$MG_CALLS"\n'
+STUB_PVS = '#!/bin/sh\nprintf "%s\\n" $MG_PVS\n'
+
+
+class Disk:
+    def __init__(self, nodes, mounts, ro="0", pvs="", lsblk_empty=False):
+        self.t = tempfile.TemporaryDirectory()
+        r = pathlib.Path(self.t.name)
+        self.bin = r / "bin"; self.bin.mkdir()
+        (self.bin / "lsblk").write_text(STUB_LSBLK); (self.bin / "lsblk").chmod(0o755)
+        for n in ("mkfs.ext4", "mkfs.xfs"):
+            (self.bin / n).write_text(STUB_MKFS); (self.bin / n).chmod(0o755)
+        (self.bin / "pvs").write_text(STUB_PVS); (self.bin / "pvs").chmod(0o755)
+        self.state = r / "state.json"
+        self.state.write_text(json.dumps({"nodes": nodes, "lsblk_empty": lsblk_empty}))
+        self.mounts = r / "mounts"
+        self.mounts.write_text("".join(f"{d} {m} ext4 rw 0 0\n" for d, m in mounts))
+        self.sys = r / "sys"
+        for n in nodes:
+            if not n.get("pk"):
+                d = self.sys / os.path.basename(n["name"]); d.mkdir(parents=True); (d / "ro").write_text(ro + "\n")
+        self.calls = r / "calls"
+        self.pvs = pvs
+        src = WRAPPER.read_text()
+        subs = [
+            ("/proc/mounts", str(self.mounts)),
+            ('[[ -b "$dev" ]]', "true"),
+            ("for c in /usr/sbin/pvs /sbin/pvs; do", f"for c in {self.bin}/pvs; do"),
+            ('rof="/sys/block/', f'rof="{self.sys}/'),
+            ("exec /usr/sbin/mkfs.ext4", f"exec {self.bin}/mkfs.ext4"),
+            ("exec /usr/sbin/mkfs.xfs ", f"exec {self.bin}/mkfs.xfs "),
+        ]
+        for a, b in subs:
+            assert a in src, f"the wrapper no longer contains {a!r} — update this test's substitutions"
+            src = src.replace(a, b)
+        self.copy = r / "mkfs-guarded"; self.copy.write_text(src)
+
+    def run(self, dev, fstype="ext4"):
+        env = {"PATH": f"{self.bin}:/usr/bin:/bin", "MG_STATE": str(self.state), "MG_CALLS": str(self.calls),
+               "MG_MOUNTS": str(self.mounts),
+               "MG_PVS": self.pvs}
+        p = subprocess.run(["bash", str(self.copy), dev, fstype], env=env, capture_output=True, text=True)
+        made = self.calls.read_text().split("\n")[0] if self.calls.exists() else ""
+        return p.returncode, p.stderr.strip(), made
+
+    def close(self):
+        self.t.cleanup()
+
+
+def disk_sdb(sdb1_fstype="ext4", sdb2_fstype=""):
+    return [{"name": "/dev/sdb", "pk": "", "fstype": ""},
+            {"name": "/dev/sdb1", "pk": "sdb", "fstype": sdb1_fstype},
+            {"name": "/dev/sdb2", "pk": "sdb", "fstype": sdb2_fstype}]
+
+
+ROOT = ("/dev/sda2", "/")
+OWN_SDB1 = [("/dev/sdb1", "/mnt/hdd_1"), ("/dev/sdb1", "/mnt/felhom-drives/hdd_1")]
+
+
+class Partitions(unittest.TestCase):
+    def check(self, mounts, dev="/dev/sdb2", nodes=None, want_ok=True, **kw):
+        d = Disk(nodes or disk_sdb(), [ROOT] + mounts, **kw)
+        try:
+            rc, err, made = d.run(dev)
+            if want_ok:
+                self.assertEqual(rc, 0, err)
+                self.assertTrue(made.endswith(f"mkfs.ext4 -F {dev}"), made)
+            else:
+                self.assertEqual(rc, 1, (mounts, made))
+                self.assertIn("REFUSED", err)
+                self.assertEqual(made, "", "a refused format must not run mkfs")
+            return err
+        finally:
+            d.close()
+
+    def test_a_free_part_on_an_unmounted_disk_is_formatted(self):
+        self.check([])   # positive control for every refusal below
+
+    def test_the_free_part_next_to_felhoms_own_drive_is_refused(self):
+        # The agent could make the „corroborating" managed mount itself: the root wrapper does not trust it.
+        self.check(OWN_SDB1, want_ok=False)
+
+    def test_a_sibling_mounted_raw_only_is_refused(self):
+        self.check([("/dev/sdb1", "/mnt/hdd_1")], want_ok=False)
+
+    def test_a_sibling_mounted_elsewhere_is_refused_even_with_a_managed_mount(self):
+        for elsewhere in ("/srv/data", "/media/usb", "/mnt/a/b", "/home/x"):
+            self.check([("/dev/sdb1", elsewhere), ("/dev/sdb1", "/mnt/felhom-drives/hdd_1")], want_ok=False)
+
+    def test_the_target_itself_mounted_raw_is_refused(self):
+        self.check([("/dev/sdb2", "/mnt/films"), ("/dev/sdb2", "/mnt/felhom-drives/films")], want_ok=False)
+
+    def test_the_target_mounted_only_under_felhom_drives_is_formatted(self):
+        self.check([("/dev/sdb2", "/mnt/felhom-drives/films")])
+
+    def test_an_unlistable_disk_is_refused(self):
+        self.check([], want_ok=False, lsblk_empty=True)
+
+    def test_the_catastrophic_cases_still_refuse(self):
+        self.check([("/dev/sdb1", "/")], want_ok=False)                     # system disk
+        self.check([], nodes=disk_sdb(sdb1_fstype="LVM2_member"), want_ok=False)  # a member signature
+        self.check([], pvs="/dev/sdb1", want_ok=False)                      # an LVM PV (pvs)
+        self.check([], ro="1", want_ok=False)                               # read-only
+
+
+if __name__ == "__main__":
+    unittest.main()

configs/test_felhom_os_apply.py

@@ -1469,6 +1469,23 @@ class PVELane(unittest.TestCase):
                          "pending-pve: installed, Proxmox-origin, never kernel/boot/firmware, never Debian or other origins")
         self.assertEqual(f.installed["libc6"], "2.41-12+deb13u3")
 
+    # 2026-10-09, demo-hp (Secure Boot on): proxmox-secure-boot-support's upgrade pulls shim-signed-common; in the pve
+    # plan that refused the whole step (R6) and skipped the night's kernel step. It is a boot-chain package: left out.
+    # RED-PROOF: drop proxmox-secure-boot-support from HOST_SLOW_RE -> it is in the plan -> this test fails.
+    def test_ring0_pending_pve_leaves_the_secure_boot_meta_out(self):
+        f = pve_fake(ring0=True)
+        f.plan["select"], f.plan["packages"] = "pending-pve", []
+        f.installed.update({"proxmox-secure-boot-support": "9.0.1"})
+        f.pending_sim = [
+            "Inst pve-manager [9.2.2] (9.2.21 Proxmox Debian Repository:stable [amd64])",
+            "Inst proxmox-secure-boot-support [9.0.1] (9.0.2 Proxmox Debian Repository:stable [all])",
+            "Inst shim-signed-common [1.48+pmx1+16.1-1+pmx1] (1.51+pmx1+16.1-2+pmx1 Proxmox Debian Repository:stable [all])",
+        ]
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(sorted(u["name"] for u in rep["upgraded"]), ["pve-manager"])
+        self.assertEqual(f.installed["proxmox-secure-boot-support"], "9.0.1")
+
     def test_select_pending_pve_needs_the_pve_layer(self):
         f = Fake()
         f.plan["layer"], f.plan["select"], f.plan["packages"] = "host", "pending-pve", []
@@ -1476,5 +1493,517 @@ class PVELane(unittest.TestCase):
         self.assertEqual((rc, rep["refused"]["code"]), (2, "R11"), rep)
 
 
+# ---------- the kernel lane (R-836, `09` §3 decision 172, `11` §5.11) ----------
+U = "1af1fcc6-639c-416b-a7e5-c4470d41a502"
+OLD, NEW = "7.0.2-6-pve", "7.0.14-22-pve"
+KERNEL_SET = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-22", "origin": "Proxmox Debian Repository"},
+              {"name": "proxmox-kernel-7.0.14-22-pve-signed", "version": "7.0.14-22", "origin": "Proxmox Debian Repository"}]
+
+
+class KFake(Fake):
+    """A Proxmox host with GRUB on UEFI: /boot on the root LV, a vfat ESP, the bundle's two generators. update-grub is
+    emulated like the real 10_linux: WITHOUT the felhom default file the NEWEST kernel becomes the default (measured,
+    R-836 — that is the defect the lane exists for); with it, the kernel it names."""
+
+    def __init__(self):
+        super().__init__()
+        self.running = OLD
+        self.boot = {OLD}
+        self.efi, self.esp_fs, self.boot_mount, self.mods, self.snippets, self.pin = True, "vfat", "", True, True, False
+        self.env = None          # None = no env block on the ESP; else {"felhom_next": ...}
+        self.tree = {}           # files put_file wrote
+        self.reboots = []
+        self.update_grubs = 0
+        self.grub_runs_in_postinst = True
+        self.installed.update({"proxmox-kernel-7.0": "7.0.2-6", "proxmox-default-kernel": "2.1.0",
+                               "pve-firmware": "3.18-3", "proxmox-kernel-7.0.2-6-pve-signed": "7.0.2-6",
+                               "pve-manager": "9.2.21"})
+        self.live.update({"proxmox-kernel-7.0": {"7.0.14-22", "7.0.2-6"},
+                          "proxmox-kernel-7.0.14-22-pve-signed": {"7.0.14-22"},
+                          "proxmox-kernel-7.0.14-23-pve-signed": {"7.0.14-23"},
+                          "pve-firmware": {"3.18-7", "3.18-3"}})
+        self.origins = {}
+        self.kernel_pending = ["Inst pve-firmware [3.18-3] (3.18-7 Proxmox Debian Repository:stable [all])",
+                               "Inst proxmox-kernel-7.0.14-22-pve-signed (7.0.14-22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst proxmox-kernel-7.0 [7.0.2-6] (7.0.14-22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst pve-manager [9.2.21] (9.2.22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst libc6 [2.41-12+deb13u3] (2.41-12+deb13u4 Debian:13.7/stable [amd64])"]
+        self.plan = {"release_id": "kernel-t1", "layer": "kernel", "lane": "slow", "vmid": 9201, "mode": "apply",
+                     "select": "pending-kernel", "packages": []}
+        self.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": True})
+        self.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": True, "tripped": False, "unclean_boots_in_window": 0})
+        self.cfg = self.render()
+
+    # -- GRUB --
+    def newest(self):
+        best = None
+        for k in self.boot:
+            if best is None or dpkg_cmp(k[:-4], "gt", best[:-4]):
+                best = k
+        return best
+
+    def render(self):
+        d = self.tree.get(osapply.KERNEL_DEFAULT_CFG)
+        if d:
+            dflt = re.search(r'GRUB_DEFAULT="([^"]+)"', d).group(1)
+        else:
+            dflt = f"gnulinux-advanced-{U}>gnulinux-{self.newest()}-advanced-{U}"
+        cfg = ('if [ "${next_entry}" ] ; then\n   set default="${next_entry}"\nelse\n'
+               f'   set default="{dflt}"\nfi\n'
+               f"submenu 'Advanced options' $menuentry_id_option 'gnulinux-advanced-{U}' {{\n")
+        for k in sorted(self.boot):
+            cfg += f"  menuentry 'Proxmox VE, with Linux {k}' $menuentry_id_option 'gnulinux-{k}-advanced-{U}' {{ }}\n"
+        cfg += "}\n"
+        if self.snippets:
+            cfg += "### BEGIN /etc/grub.d/01_felhom_oneshot ###\nload_env felhom_next\n"
+            cfg += "".join(f"menuentry 'Felhom one-shot: {k}' --id felhom-oneshot-{k} {{ }}\n" for k in sorted(self.boot))
+        return cfg
+
+    def lexists(self, p):
+        if p == "/sys/firmware/efi":
+            return self.efi
+        if p.startswith("/usr/lib/grub/x86_64-efi/"):
+            return self.mods
+        if p in (osapply.ONESHOT_SNIPPET, osapply.ONESHOT_ENTRIES):
+            return self.snippets
+        if p == osapply.KERNEL_PIN_FILE:
+            return self.pin
+        m = re.match(r"^/boot/(vmlinuz|initrd\.img)-(.+)$", p)
+        if m:
+            return m.group(2) in self.boot
+        return p in self.tree
+
+    def put_file(self, path, data, mode):
+        self.tree[path] = data.decode()
+
+    def read_file(self, p):
+        if p == osapply.GRUB_CFG:
+            return self.cfg
+        if p in self.tree:
+            return self.tree[p]
+        return super().read_file(p)
+
+    def host(self, argv, timeout=600, stdin=None):
+        if argv[0] == "uname":
+            self.calls.append(("host", argv))
+            return 0, self.running + "\n", ""
+        if argv[0] == "findmnt":
+            self.calls.append(("host", argv))
+            if argv[-1] == osapply.ESP_MOUNT:
+                return (0, self.esp_fs + "\n", "") if self.esp_fs else (1, "", "")
+            return (0, self.boot_mount + "\n", "") if self.boot_mount else (1, "", "")
+        if argv[0] == "grub-editenv":
+            self.calls.append(("host", argv))
+            if argv[2] == "list":
+                return (1, "", "no such file") if self.env is None else \
+                    (0, "".join(f"{k}={v}\n" for k, v in self.env.items()), "")
+            if argv[2] == "create":
+                self.env = {}
+                return 0, "", ""
+            if argv[2] == "set":
+                k, v = argv[3].split("=", 1)
+                self.env[k] = v
+                return 0, "", ""
+            if argv[2] == "unset":
+                self.env.pop(argv[3], None)
+                return 0, "", ""
+        if argv[0] == "update-grub":
+            self.calls.append(("host", argv))
+            self.update_grubs += 1
+            self.cfg = self.render()
+            return 0, "", ""
+        if argv[0] == "mkdir":
+            self.calls.append(("host", argv))
+            return 0, "", ""
+        if argv[:2] == ["systemctl", "reboot"]:
+            self.calls.append(("host", argv))
+            self.reboots.append(self.running)
+            return 0, "", ""
+        return super().host(argv, timeout, stdin)
+
+    def emulate(self, argv):
+        a = [x for x in argv if not re.match(r"^[A-Z_]+=", x) and x != "env"]
+        if a[0] == "apt-get" and "install" in a and "-s" not in a and "--print-uris" not in a and "-f" not in a:
+            if self.install_rc:
+                return self.install_rc, "", "E: boom"
+            for x in a:
+                if "=" in x and not x.startswith("-") and "::" not in x:
+                    n, v = x.split("=", 1)
+                    self.installed[n] = v
+                    m = re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n)
+                    if m:
+                        self.installed[f"proxmox-kernel-{v}-pve-signed"] = v
+                    if m or osapply.KERNEL_IMAGE_RE.match(n):
+                        self.boot.add(v + "-pve")
+            if self.grub_runs_in_postinst:
+                self.cfg = self.render()   # the kernel's postinst runs update-grub (zz-update-grub)
+            return 0, "Setting up proxmox-kernel ...\n", ""
+        return super().emulate(argv)
+
+    def sim(self, a):
+        if "--print-uris" in a:
+            return 0, "", ""
+        if "dist-upgrade" in a:
+            return 0, "\n".join(self.kernel_pending) + "\n", ""
+        out, named = "", set()
+        for x in a:
+            if "=" in x and not x.startswith("-") and "::" not in x:
+                named.add(x.split("=", 1)[0])
+        for x in a:
+            if "=" in x and not x.startswith("-") and "::" not in x:
+                n, v = x.split("=", 1)
+                if v not in self.avail(n):
+                    return 100, "", f"E: Version '{v}' for '{n}' was not found"
+                o = self.origins.get(n, PVE)
+                out += f"Inst {n} [{self.installed[n]}] ({v} {o} [amd64])\n" if n in self.installed else f"Inst {n} ({v} {o} [amd64])\n"
+                if re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n):
+                    img = f"proxmox-kernel-{v}-pve-signed"
+                    if img not in self.installed and img not in named:
+                        out += f"Inst {img} ({v} {PVE} [amd64])\n"
+        out += "".join(l + "\n" for l in self.extra_sim)
+        return 0, out, ""
+
+
+def kfake(**kw):
+    f = KFake()
+    for k, v in kw.items():
+        setattr(f, k, v)
+    return f
+
+
+def kmode(f, mode, **extra):
+    f.plan = {"release_id": "kernel-t1", "layer": "kernel", "lane": "slow", "vmid": 9201, "mode": mode, "packages": []}
+    f.plan.update(extra)
+    return run(f)
+
+
+def staged(f=None):
+    f = f or kfake()
+    rc, rep = run(f)
+    assert rc == 0, rep
+    return f
+
+
+class KernelLane(unittest.TestCase):
+    """R-836 / `09` §3 decision 172: stage a kernel once through the ESP flag; the default moves only after a healthy
+    one-shot boot. Red-proof: audits/kernel-lane-2026-10-07/A/redproof.txt."""
+
+    def refused(self, f, code, mode=None, **extra):
+        rc, rep = kmode(f, mode, **extra) if mode else run(f)
+        self.assertEqual(rc, 2, rep)
+        self.assertEqual(rep["refused"]["code"], code, rep)
+        return rep
+
+    # --- the four red tests the brief names (Part A 3) ---
+    def test_installing_a_kernel_does_not_change_the_grub_default(self):
+        f = kfake()
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertIn(NEW, f.boot, "the new kernel was installed")
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD,
+                         "the default must stay the kernel the box runs (R-836: an install made the new one default)")
+        self.assertIn(f"gnulinux-{OLD}-advanced-{U}", f.tree[osapply.KERNEL_DEFAULT_CFG])
+        self.assertEqual(f.env, {"felhom_next": NEW}, "the ONLY way to the new kernel is the one-shot flag")
+        self.assertEqual(f.reboots, [], "staging never reboots")
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        self.assertEqual((st["phase"], st["from"], st["to"]), ("staged", OLD, NEW))
+        self.assertEqual(rep["kernel"]["default"], OLD)
+
+    def test_a_box_without_the_esp_flag_is_refused(self):
+        for attr, val, frag in (("esp_fs", "ext4", "vfat"), ("efi", False, "UEFI"), ("snippets", False, "bundle"),
+                                ("mods", False, "module"), ("boot_mount", "/boot", "separate"), ("pin", True, "pinned")):
+            f = kfake(**{attr: val})
+            rep = self.refused(f, "R20")
+            self.assertIn(frag, rep["refused"]["reason"], attr)
+            self.assertNotIn(NEW, f.boot, f"{attr}: nothing may be installed on a refusal")
+            self.assertIsNone(f.env, f"{attr}: no flag on a refusal")
+
+    def test_a_reboot_without_the_flag_is_refused(self):
+        f = staged()
+        f.env = {"felhom_next": ""}
+        self.refused(f, "R22", mode="kernel-reboot")
+        self.assertEqual(f.reboots, [])
+
+    def test_a_kernel_outside_the_approved_set_is_refused(self):
+        # a signed set that names only the meta-package: the image the sources pull in was never signed for
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f.plan.update(select="listed", packages=[dict(KERNEL_SET[0])],
+                      signed=signed_job(packages=[KERNEL_SET[0]], op="os_kernel_step"))
+        self.refused(f, "R23")
+        self.assertNotIn(NEW, f.boot)
+        # a signed set names 7.0.14-22; the sources would ALSO bring 7.0.14-23
+        f2 = kfake()
+        f2.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f2.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                       signed=signed_job(packages=KERNEL_SET, op="os_kernel_step"))
+        f2.extra_sim = ["Inst proxmox-kernel-7.0.14-23-pve-signed (7.0.14-23 Proxmox Debian Repository:stable [amd64])"]
+        self.refused(f2, "R23")
+        # a name that is not a kernel package at all
+        g = kfake()
+        g.plan.update(select="listed", packages=[{"name": "pve-manager", "version": "9.2.22", "origin": "Proxmox Debian Repository"}])
+        self.refused(g, "R23")
+        # the household was told about another kernel
+        h = kfake()
+        h.plan["expect_kver"] = "7.0.14-23-pve"
+        self.refused(h, "R23")
+        self.assertNotIn(NEW, h.boot)
+
+    def test_the_snippet_clears_the_flag_on_use(self):
+        """01_felhom_oneshot: the flag is copied, CLEARED and SAVED before any `set default`, all inside the one branch
+        that runs only when the flag is set; a default is set only for an installed kernel's own entry."""
+        text = (HERE / "felhom-grub-oneshot.sh").read_text()
+        body = text[text.index("cat <<EOF"):]
+        i_copy = body.index('set felhom_boot="\\${felhom_next}"')
+        i_clear = body.index("set felhom_next=\n")
+        i_save = body.index("save_env -f (\\$felhom_esp)/EFI/felhom/oneshot.env felhom_next")
+        i_default = body.index('set default="felhom-oneshot-%s"')
+        self.assertLess(i_copy, i_clear)
+        self.assertLess(i_clear, i_save)
+        self.assertLess(i_save, i_default, "the flag must be cleared on disk BEFORE GRUB boots anything")
+        self.assertIn('if [ "${felhom_boot}" = "%s" ]', body, "a default only for a kernel that is installed")
+        self.assertIn(osapply.ONESHOT_ENV[len(osapply.ESP_MOUNT):], text, "the wrapper and GRUB name the same env file")
+
+    # --- the rest of the stage ---
+    def test_option_c_options_are_on_the_one_shot_entry_only(self):
+        text = (HERE / "felhom-grub-oneshot-entries.sh").read_text()
+        self.assertIn(osapply.ONESHOT_ARGS, text)
+        self.assertIn("--id felhom-oneshot-$k", text)
+        self.assertNotIn("set default", text, "the entries file never sets the default")
+
+    def test_both_generators_ride_the_bundle(self):
+        self.assertEqual(osapply.BUNDLE_DESTS[osapply.ONESHOT_SNIPPET][1:4], ("felhom-grub-oneshot.sh", 0o755, "sh"))
+        self.assertEqual(osapply.BUNDLE_DESTS[osapply.ONESHOT_ENTRIES][1:4], ("felhom-grub-oneshot-entries.sh", 0o755, "sh"))
+
+    def test_ring0_pending_kernel_takes_only_the_kernel_set(self):
+        f = kfake()
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "ring0")
+        self.assertEqual(sorted(u["name"] for u in rep["upgraded"]), ["proxmox-kernel-7.0", "pve-firmware"])
+        self.assertEqual(f.installed["pve-manager"], "9.2.21", "a Proxmox userspace package is the pve lane's")
+        self.assertEqual(f.installed["libc6"], "2.41-12+deb13u3", "a Debian package is the fast lane's")
+
+    def test_signed_listed_set_is_installed(self):
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                      signed=signed_job(packages=KERNEL_SET, op="os_kernel_step"))
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "signed")
+        self.assertEqual(f.env, {"felhom_next": NEW})
+
+    def test_no_authority_and_the_wrong_op_are_refused(self):
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        self.refused(f, "R3")
+        g = kfake()
+        g.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        g.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                      signed=signed_job(packages=KERNEL_SET, op="os_pve_step"))
+        self.refused(g, "R3")
+
+    def test_fast_lane_byo_and_wrong_select_are_refused(self):
+        f = kfake()
+        f.plan["lane"] = "fast"
+        self.refused(f, "R3")
+        g = kfake()
+        g.files[osapply.INSTALL_STATE] = json.dumps({"mode": "byo"})
+        self.refused(g, "R12")
+        h = kfake()
+        h.plan["select"] = "pending-pve"
+        self.refused(h, "R11")
+        k = kfake()
+        k.plan.update(layer="host", lane="fast", mode="kernel-status")
+        self.refused(k, "R11")
+
+    def test_the_crash_guard_must_be_armed_and_quiet(self):
+        f = kfake()
+        f.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": False, "tripped": True, "unclean_boots_in_window": 2})
+        self.refused(f, "R21")
+        g = kfake()
+        g.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": True, "tripped": False, "unclean_boots_in_window": 1})
+        self.refused(g, "R21")
+        h = kfake()
+        del h.files[osapply.CRASH_GUARD_STATE]
+        self.refused(h, "R21")
+        self.assertNotIn(NEW, h.boot)
+
+    def test_never_two_steps_in_one_night(self):
+        f = staged()
+        self.refused(f, "R22")  # still staged
+        g = staged()
+        st = json.loads(g.tree[osapply.KERNEL_STATE])
+        st["phase"] = "good"
+        g.tree[osapply.KERNEL_STATE] = json.dumps(st)
+        g.clock += 3600
+        self.refused(g, "R22")  # done, but within 20 h
+
+    def test_removal_new_non_kernel_two_kernels_and_older_are_refused(self):
+        f = kfake(extra_sim=["Remv pve-firmware [3.18-3]"])
+        self.refused(f, "R4")
+        g = kfake(extra_sim=["Inst proxmox-new-thing (1.0 Proxmox Debian Repository:stable [all])"])
+        self.refused(g, "R6")
+        h = kfake(extra_sim=["Inst proxmox-kernel-7.0.14-23-pve-signed (7.0.14-23 Proxmox Debian Repository:stable [amd64])"])
+        self.refused(h, "R23")
+        k = kfake(running="7.0.14-23-pve")
+        k.boot = {"7.0.14-23-pve"}
+        k.cfg = k.render()
+        self.refused(k, "R23")
+        m = kfake()
+        m.origins = {"proxmox-kernel-7.0": DEB}
+        self.refused(m, "R2")
+
+    # R-898: ring 0 stages EXACTLY the told kernel (select listed, the set derived from it) — even when the sources
+    # offer a newer one by night; a told version that can no longer be installed is refused BEFORE any change (R7).
+    def test_ring0_listed_installs_the_told_kernel_not_the_newest(self):
+        f = kfake()
+        f.live["proxmox-kernel-7.0"] = {"7.0.14-20", "7.0.14-22", "7.0.2-6"}
+        f.live["proxmox-kernel-7.0.14-20-pve-signed"] = {"7.0.14-20"}
+        told = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"},
+                {"name": "proxmox-kernel-7.0.14-20-pve-signed", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"}]
+        f.plan.update(select="listed", packages=told, expect_kver="7.0.14-20-pve")
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "ring0")
+        self.assertEqual(f.env, {"felhom_next": "7.0.14-20-pve"})
+        self.assertEqual(f.installed["proxmox-kernel-7.0"], "7.0.14-20")
+        self.assertNotIn("7.0.14-22-pve", f.boot)
+
+    def test_ring0_told_kernel_gone_is_refused_before_any_change(self):
+        f = kfake()
+        f.live["proxmox-kernel-7.0"] = {"7.0.14-22"}   # 7.0.14-20 is no longer in the archive
+        told = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"},
+                {"name": "proxmox-kernel-7.0.14-20-pve-signed", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"}]
+        f.plan.update(select="listed", packages=told, expect_kver="7.0.14-20-pve")
+        rep = self.refused(f, "R7")
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_DEFAULT_CFG, f.tree, "refused before the default was even pinned")
+        self.assertEqual(f.installed["proxmox-kernel-7.0"], "7.0.2-6")
+
+    def test_nothing_pending_changes_nothing(self):
+        f = kfake(kernel_pending=[])
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["upgraded"], [])
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_STATE, f.tree)
+
+    def test_a_failed_install_writes_no_flag(self):
+        f = kfake(install_rc=100)
+        rc, rep = run(f)
+        self.assertEqual(rc, 3, rep)
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_STATE, f.tree)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+
+    def test_a_postinst_without_update_grub_is_regenerated_and_proved(self):
+        f = kfake(grub_runs_in_postinst=False)
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertIn(f"felhom-oneshot-{NEW}", f.cfg)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+
+    # --- the reboot, the boot, good / revert ---
+    def test_reboot_of_a_staged_step(self):
+        f = staged()
+        rc, rep = kmode(f, "kernel-reboot")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.reboots, [OLD])
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        self.assertEqual(st["phase"], "oneshot")
+        self.assertIn("host_services", st["health_before"])
+
+    def test_reboot_needs_a_staged_step(self):
+        self.refused(kfake(), "R22", mode="kernel-reboot")
+
+    def boot_into(self, f, kver):
+        f.running = kver
+        if f.env and f.env.get("felhom_next"):
+            f.env["felhom_next"] = ""   # GRUB cleared it (01_felhom_oneshot)
+        return kmode(f, "kernel-boot")
+
+    def test_healthy_one_shot_becomes_the_default(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        rc, rep = self.boot_into(f, NEW)
+        self.assertEqual((rc, rep["kernel_event"], rep["kernel"]["phase"]), (0, "judging", "judging"), rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD, "judging does not move the default")
+        rc, rep = kmode(f, "kernel-good")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), NEW)
+        self.assertEqual(rep["kernel"]["phase"], "good")
+
+    def test_a_panic_falls_back_and_is_recorded(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        rc, rep = self.boot_into(f, OLD)
+        self.assertEqual((rc, rep["kernel_event"]), (0, "fell_back"), rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+        self.refused(f, "R22", mode="kernel-good")
+
+    def test_one_self_revert_then_never_again(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        rc, rep = kmode(f, "kernel-revert", reason="the customer guest is not running")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.reboots, [OLD, NEW])
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD, "the self-revert boots the default, the old kernel")
+        rc, rep = self.boot_into(f, OLD)
+        self.assertEqual(rep["kernel_event"], "self_reverted")
+        # the same step can never revert again
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        st["phase"] = "judging"
+        f.tree[osapply.KERNEL_STATE] = json.dumps(st)
+        f.running = NEW
+        self.refused(f, "R22", mode="kernel-revert")
+        self.assertEqual(len(f.reboots), 2)
+
+    def test_a_revert_that_comes_back_new_is_never_retried(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        kmode(f, "kernel-revert")
+        rc, rep = self.boot_into(f, NEW)
+        self.assertEqual(rep["kernel_event"], "revert_failed")
+        self.refused(f, "R22", mode="kernel-revert")
+
+    def test_revert_refuses_an_unknown_default(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        f.tree[osapply.KERNEL_DEFAULT_CFG] = f'GRUB_DEFAULT="gnulinux-advanced-{U}>gnulinux-9.9.9-1-pve-advanced-{U}"\n'
+        f.cfg = f.render()
+        self.refused(f, "R20", mode="kernel-revert")
+        self.assertEqual(len(f.reboots), 1)
+
+    def test_cancel_clears_the_flag(self):
+        f = staged()
+        rc, rep = kmode(f, "kernel-cancel")
+        self.assertEqual(rc, 0, rep)
+        self.assertFalse(f.env.get("felhom_next"), "the flag is gone")
+        self.assertEqual(rep["kernel"]["phase"], "cancelled")
+
+    def test_status_is_read_only_and_names_setup_problems(self):
+        f = kfake(esp_fs="ext4")
+        rc, rep = kmode(f, "kernel-status")
+        self.assertEqual(rc, 0, rep)
+        self.assertTrue(rep["kernel"]["setup_problems"])
+        self.assertEqual(f.tree, {})
+        self.assertFalse([c for c in f.calls if c[1][0] in ("update-grub", "systemctl", "apt-get")])
+
+    def test_facts_carry_the_kernel_lane(self):
+        f = staged()
+        f.plan = {"release_id": "facts", "layer": "host", "lane": "fast", "vmid": 9201, "mode": "facts", "packages": []}
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        h = rep["facts"]["host"]
+        self.assertEqual(h["kernel_lane"]["phase"], "staged")
+        self.assertEqual(h["kernel_next_boot"], NEW)
+        self.assertIn("one-shot", h["kernel_next_boot_source"])
+
+
 if __name__ == "__main__":
     unittest.main()

configs/test_felhom_vzdump_partial_clean.py

@@ -0,0 +1,198 @@
+#!/usr/bin/env python3
+"""Tests for configs/felhom-vzdump-partial-clean (R-1006): it removes a DEAD half-written vzdump backup and refuses
+everything else. Each refusal has a positive control: the same setup without the one condition is removed — so a
+test cannot pass because the helper refuses everything. A fake storage.cfg and a fake /proc; nothing real is touched.
+Run: python3 configs/test_felhom_vzdump_partial_clean.py   (also run by internal/backup's Go test)
+"""
+import os, pathlib, subprocess, tempfile, time, unittest
+
+HELPER = pathlib.Path(__file__).resolve().parent / "felhom-vzdump-partial-clean"
+BOOT = 1_791_967_481
+NAME = "vzdump-lxc-9201-2026_10_14-10_42_25"
+
+
+class Box:
+    """A temp tree: a dir storage `local` (path vz), an lvmthin `local-lvm`, a dir storage `other`, and a fake /proc."""
+
+    def __init__(self):
+        self.t = tempfile.TemporaryDirectory()
+        r = pathlib.Path(self.t.name)
+        self.vz, self.other, self.nas, self.proc = r / "vz", r / "other", r / "nas", r / "proc"
+        for d in (self.vz / "dump", self.other / "dump", self.nas / "dump", self.proc):
+            d.mkdir(parents=True)
+        (self.proc / "stat").write_text(f"cpu  1 2 3\nbtime {BOOT}\n")
+        self.cfg = r / "storage.cfg"
+        self.cfg.write_text(f"dir: local\n\tpath {self.vz}\n\tcontent iso,backup\n\n"
+                            f"lvmthin: local-lvm\n\tthinpool data\n\tvgname pve\n\n"
+                            f"dir: other\n\tpath {self.other}\n\tcontent backup\n\n"
+                            f"nfs: nas\n\tpath {self.nas}\n\tserver 192.0.2.1\n\texport /x\n\tcontent backup\n")
+        self.pid = 1000
+
+    def partial(self, name=NAME + ".tar.dat", mtime=BOOT - 100, where=None, size=4096):
+        p = (where or self.vz / "dump") / name
+        if name.endswith(".tmp"):
+            (p / "etc" / "vzdump").mkdir(parents=True)
+            (p / "etc" / "vzdump" / "pct.conf").write_text("x")
+            for q in [p / "etc" / "vzdump" / "pct.conf", p / "etc" / "vzdump", p / "etc", p]:
+                os.utime(q, (mtime, mtime))
+        else:
+            p.write_bytes(b"\0" * size)
+            os.utime(p, (mtime, mtime))
+        return p
+
+    def process(self, cmdline, fds=(), cwd=None):
+        self.pid += 1
+        d = self.proc / str(self.pid)
+        (d / "fd").mkdir(parents=True)
+        (d / "cmdline").write_bytes(b"\0".join(a.encode() for a in cmdline) + b"\0")
+        for i, f in enumerate(fds):
+            os.symlink(str(f), d / "fd" / str(i + 3))
+        os.symlink(str(cwd or "/"), d / "cwd")
+
+    def run(self, storage, vmid, name, quiet=120):
+        script = (f'source "{HELPER}"; STORAGE_CFG="{self.cfg}"; PROC="{self.proc}"; QUIET_S={quiet}; '
+                  f'main "$@"')
+        r = subprocess.run(["bash", "-c", script, "x", storage, str(vmid), name], capture_output=True, text=True)
+        return r.returncode, r.stdout + r.stderr
+
+
+class Removes(unittest.TestCase):
+    def test_dead_tar_dat_before_boot(self):
+        b = Box(); p = b.partial()
+        rc, out = b.run("local", 9201, p.name)
+        self.assertEqual(rc, 0, out); self.assertFalse(p.exists()); self.assertIn("written before this boot", out)
+
+    def test_dead_tmp_dir_before_boot(self):
+        b = Box(); p = b.partial(NAME + ".tmp")
+        rc, out = b.run("local", 9201, p.name)
+        self.assertEqual(rc, 0, out); self.assertFalse(p.exists())
+
+    def test_quiet_partial_after_boot(self):
+        b = Box(); p = b.partial(mtime=int(time.time()) - 300)
+        rc, out = b.run("local", 9201, p.name)
+        self.assertEqual(rc, 0, out); self.assertFalse(p.exists()); self.assertIn("untouched", out)
+
+    def test_qemu_vma_dat(self):
+        b = Box(); p = b.partial("vzdump-qemu-341-2026_10_14-10_42_25.vma.dat")
+        rc, out = b.run("local", 341, p.name)
+        self.assertEqual(rc, 0, out); self.assertFalse(p.exists())
+
+
+class Keeps(unittest.TestCase):
+    """Each case: (setup that must be REFUSED, the same setup that must be REMOVED)."""
+
+    def pair(self, refuse, control, quiet=120):
+        b = Box(); target, args = refuse(b)
+        rc, out = b.run(*args, quiet=quiet)
+        self.assertNotEqual(rc, 0, f"must refuse: {out}")
+        self.assertIn("REFUSED", out)
+        self.assertTrue(os.path.lexists(target), "a refused entry must still exist")
+        c = Box(); ctarget, cargs = control(c)
+        crc, cout = c.run(*cargs, quiet=quiet)
+        self.assertEqual(crc, 0, f"positive control must be removed: {cout}")
+        self.assertFalse(os.path.lexists(ctarget))
+
+    def test_complete_archive_of_same_vmid(self):
+        self.pair(lambda b: (b.partial(NAME + ".tar.zst"), ("local", 9201, NAME + ".tar.zst")),
+                  lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_log_and_notes(self):
+        for suffix in (".log", ".tar.zst.notes"):
+            self.pair(lambda b, s=suffix: (b.partial(NAME + s), ("local", 9201, NAME + s)),
+                      lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_partial_of_another_vmid(self):
+        other = "vzdump-lxc-9202-2026_10_14-10_42_25.tar.dat"
+        self.pair(lambda b: (b.partial(other), ("local", 9201, other)),
+                  lambda b: (b.partial(other), ("local", 9202, other)))
+
+    def test_partial_on_a_non_dir_storage(self):
+        self.pair(lambda b: (b.partial(), ("local-lvm", 9201, NAME + ".tar.dat")),
+                  lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_partial_on_a_network_storage_with_a_path(self):
+        # an nfs storage HAS a path: only the „dir only" rule (both its guards) can refuse it
+        self.pair(lambda b: (b.partial(where=b.nas / "dump"), ("nas", 9201, NAME + ".tar.dat")),
+                  lambda b: (b.partial(where=b.other / "dump"), ("other", 9201, NAME + ".tar.dat")))
+
+    def test_partial_on_another_storage_than_named(self):
+        self.pair(lambda b: (b.partial(where=b.other / "dump"), ("local", 9201, NAME + ".tar.dat")),
+                  lambda b: (b.partial(where=b.other / "dump"), ("other", 9201, NAME + ".tar.dat")))
+
+    def test_unknown_storage(self):
+        self.pair(lambda b: (b.partial(), ("nosuch", 9201, NAME + ".tar.dat")),
+                  lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_vzdump_task_in_flight(self):
+        def refuse(b):
+            p = b.partial(); b.process(["task UPID:demo-hp:001:002:6ACF4071:vzdump:9201:felhom-agent@pve!agent:"]); return p, ("local", 9201, p.name)
+        def control(b):
+            p = b.partial(); b.process(["task UPID:demo-hp:001:002:6ACF4071:vzrestore:9202:root@pam:"]); return p, ("local", 9201, p.name)
+        self.pair(refuse, control)
+
+    def test_any_vzdump_job_even_without_the_vmid(self):
+        # a job for several guests: `vzdump::` — and a vzdump for ANOTHER guest — both refuse
+        for cmd in (["task UPID:demo-hp:001:002:6ACF4071:vzdump::root@pam:"],
+                    ["task UPID:demo-hp:001:002:6ACF4071:vzdump:9202:felhom-agent@pve!agent:"]):
+            def refuse(b, c=cmd):
+                p = b.partial(); b.process(c); return p, ("local", 9201, p.name)
+            def control(b):
+                p = b.partial(); b.process(["task UPID:demo-hp:001:002:6ACF4071:vzstart:9202:root@pam:"]); return p, ("local", 9201, p.name)
+            self.pair(refuse, control)
+
+    def test_vzdump_command_for_the_vmid(self):
+        def refuse(b):
+            p = b.partial(); b.process(["/usr/bin/perl", "/usr/bin/vzdump", "9201", "--storage", "local"]); return p, ("local", 9201, p.name)
+        def control(b):
+            p = b.partial(); b.process(["/usr/bin/perl", "/usr/bin/vzdumpfoo", "9201"]); return p, ("local", 9201, p.name)
+        self.pair(refuse, control)
+
+    def test_file_held_open_by_an_orphan_writer(self):
+        def refuse(b):
+            p = b.partial(); b.process(["zstd", "--threads=1"], fds=[p]); return p, ("local", 9201, p.name)
+        def control(b):
+            p = b.partial(); b.process(["zstd", "--threads=1"], fds=[b.vz / "dump" / "something-else"]); return p, ("local", 9201, p.name)
+        self.pair(refuse, control)
+
+    def test_tmp_dir_with_a_process_inside(self):
+        def refuse(b):
+            p = b.partial(NAME + ".tmp"); b.process(["tar", "cpf", "-"], cwd=p / "etc"); return p, ("local", 9201, p.name)
+        def control(b):
+            p = b.partial(NAME + ".tmp"); b.process(["tar", "cpf", "-"], cwd=b.vz); return p, ("local", 9201, p.name)
+        self.pair(refuse, control)
+
+    def test_recently_written_after_boot(self):
+        self.pair(lambda b: (b.partial(mtime=int(time.time()) - 10), ("local", 9201, NAME + ".tar.dat")),
+                  lambda b: (b.partial(mtime=int(time.time()) - 300), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_symlink(self):
+        def refuse(b):
+            real = b.partial(where=b.vz)
+            link = b.vz / "dump" / (NAME + ".tar.dat")
+            os.symlink(real, link)
+            return link, ("local", 9201, link.name)
+        # quiet=0: the link was made just now, so only the symlink rule may refuse it
+        self.pair(refuse, lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")), quiet=0)
+
+    def test_near_miss_names(self):
+        for bad in (NAME + ".tar.dat.bak", "vzdump-lxc-92011-2026_10_14-10_42_25.tar.dat", NAME + ".tar.da",
+                    "x" + NAME + ".tar.dat", NAME + ".TAR.DAT", "vzdump-lxc-9201-2026_10_14-10_42.tar.dat"):
+            self.pair(lambda b, n=bad: (b.partial(n), ("local", 9201, n)),
+                      lambda b: (b.partial(), ("local", 9201, NAME + ".tar.dat")))
+
+    def test_path_traversal_and_bad_args(self):
+        b = Box(); p = b.partial()
+        for args in (("local", 9201, "../dump/" + p.name), ("local", 9201, ""), ("loc al", 9201, p.name),
+                     ("local", "9201x", p.name), ("local", 12, p.name)):
+            rc, out = b.run(*args)
+            self.assertNotEqual(rc, 0, f"{args}: {out}")
+        self.assertTrue(p.exists())
+
+    def test_wrong_kind(self):
+        def refuse(b):  # a FILE named .tmp
+            p = b.vz / "dump" / (NAME + ".tmp"); p.write_bytes(b"x"); os.utime(p, (BOOT - 100, BOOT - 100)); return p, ("local", 9201, p.name)
+        self.pair(refuse, lambda b: (b.partial(NAME + ".tmp"), ("local", 9201, NAME + ".tmp")))
+
+
+if __name__ == "__main__":
+    unittest.main()

internal/backup/backup_state.go

@@ -103,6 +103,29 @@ func (s *BackupSuccessState) LastKnownSuccess(target string, vmid int) (time.Tim
 	return e.at, ok
 }
 
+// KnownBackupSuccesses returns every saved success as a host-report record (the collector's
+// KnownBackupReporter, so the hub keeps its evidence across a restart). Only the tier, guest and start
+// time are known; the archive name is not saved and stays empty. Sorted for a stable report.
+func (s *BackupSuccessState) KnownBackupSuccesses() []hub.Backup {
+	if s == nil {
+		return nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	out := make([]hub.Backup, 0, len(s.last))
+	for _, e := range s.last {
+		out = append(out, hub.Backup{TargetID: e.target, VMID: e.vmid, Success: true, CrashConsistent: true,
+			StartedAt: e.at.Format(time.RFC3339), UncoveredVolumes: []string{}})
+	}
+	sort.Slice(out, func(i, j int) bool {
+		if out[i].TargetID != out[j].TargetID {
+			return out[i].TargetID < out[j].TargetID
+		}
+		return out[i].VMID < out[j].VMID
+	})
+	return out
+}
+
 func (s *BackupSuccessState) saveLocked() error {
 	entries := make([]backupSuccessJSON, 0, len(s.last))
 	for _, e := range s.last {

internal/backup/backup_state_test.go

@@ -57,3 +57,20 @@ func TestBackupSuccessState_CorruptFileIsEmpty(t *testing.T) {
 		t.Fatal("a corrupt file must read as nothing known")
 	}
 }
+
+// The saved successes come back as host-report records: success, tier, guest, start time (R-894 → the
+// host report, 2026-10-09). A new state read from the same file gives the same records (the restart case).
+func TestBackupSuccessState_KnownBackupSuccessesSurviveAReopen(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "backup-success-state.json")
+	s := NewBackupSuccessState(path)
+	if err := s.RecordBackupSuccess("felhom-backup", hub.Backup{VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z"}); err != nil {
+		t.Fatal(err)
+	}
+	got := NewBackupSuccessState(path).KnownBackupSuccesses()
+	if len(got) != 1 || !got[0].Success || got[0].TargetID != "felhom-backup" || got[0].VMID != 9201 || got[0].StartedAt != "2026-10-09T02:40:16Z" {
+		t.Fatalf("got %+v", got)
+	}
+	if got[0].UncoveredVolumes == nil {
+		t.Fatal("uncovered_volumes must marshal as [], not null")
+	}
+}

internal/backup/r685_space_test.go

@@ -81,3 +81,28 @@ func TestR685_FailsOpen(t *testing.T) {
 		}
 	}
 }
+
+// TestR1006_LeftoverCleanupRunsBeforeThePreflight — the night of 2026-10-14: a 12.2 GB half-written archive from a power
+// cut held the space, so every later backup was skipped. The cleanup step runs BEFORE the preflight reads the free space:
+// here it „removes" the leftover (free 4 → 16 GiB) and the backup then fits and runs.
+//
+// RED-PROOF: drop the r.beforeBackup call from backup() (or move it after spaceFits) → the backup is skipped → fails.
+func TestR1006_LeftoverCleanupRunsBeforeThePreflight(t *testing.T) {
+	api := spaceAPI(4*gib, 8182759056, "dir")
+	r := NewBackupRunner(api, "local", proxmox.ModeSnapshot, "", "keep-last=1", quiet())
+	var got []string
+	r.SetBeforeBackup(func(_ context.Context, storage string, vmid int) {
+		got = append(got, storage)
+		if vmid != 9201 {
+			t.Errorf("cleanup asked for vmid %d", vmid)
+		}
+		api.storages[0].Avail = 16 * gib
+	})
+	_, _ = r.Backup(context.Background(), 9201)
+	if len(got) != 1 || got[0] != "local" {
+		t.Fatalf("the cleanup must run once for this target, got %v", got)
+	}
+	if len(api.vzdumps) != 1 {
+		t.Fatalf("after the cleanup freed the space the backup must run, vzdumps=%d", len(api.vzdumps))
+	}
+}

internal/backup/runner.go

@@ -58,8 +58,11 @@ type BackupRunner struct {
 	// tier cannot have that accident — its keep_last defaults to 0 (never prune), so any value
 	// there is a deliberate act.
 	allowPBSPrune bool
-	logger        *slog.Logger
-	now           func() time.Time
+	// beforeBackup runs just before the space preflight (R-1006): it removes a dead half-written vzdump of this guest on
+	// this target, so a leftover from a power cut cannot hold the space this backup needs. nil = nothing.
+	beforeBackup func(ctx context.Context, storage string, vmid int)
+	logger       *slog.Logger
+	now          func() time.Time
 	// rejected remembers the volids already announced by warnRejectedArchiveOnce, so an incomplete
 	// archive is reported ONCE rather than on every 5-minute due-check. Bounded in practice: one
 	// entry per aborted upload, and a process restart clears it. Guarded by rejectedMu because the
@@ -102,6 +105,11 @@ func NewBackupRunnerFull(api BackupAPI, target string, mode proxmox.BackupMode,
 		now: func() time.Time { return time.Now().UTC() }}
 }
 
+// SetBeforeBackup sets the step run just before the space preflight (R-1006: the dead-leftover cleanup).
+func (r *BackupRunner) SetBeforeBackup(fn func(ctx context.Context, storage string, vmid int)) {
+	r.beforeBackup = fn
+}
+
 // localPruneSpec returns the `--prune-backups` spec to apply to THIS backup, or "" to skip pruning. It
 // applies the configured retention ONLY when the target is a non-PBS storage — PBS offsite retention is a
 // separate lifecycle and must never be pruned by the per-run flag (§9). Fail-safe: if the target's type
@@ -183,6 +191,9 @@ func (r *BackupRunner) backup(ctx context.Context, vmid int, onSnapshot func())
 	// R-685 (v0.134.0): will the new archive FIT on a local target? Asked before anything runs, so a
 	// target that cannot hold it is a named SKIP with the numbers, not a nightly "No space left on
 	// device" that only the vzdump log explains (demo-hp, every night from 2026-09-23 — R-684).
+	if r.beforeBackup != nil {
+		r.beforeBackup(ctx, r.target, vmid)
+	}
 	if ok, why := r.spaceFits(ctx, vmid); !ok {
 		rec.Error = BackupSkipNoSpacePrefix + why
 		rec.DurationSeconds = time.Since(start).Seconds()

internal/capability/manifest.go

@@ -115,6 +115,11 @@ var manifest = []Capability{
 	{"guesthook-register", "pre-start hook register", "/usr/sbin/pct", []string{"set", "9201", "--hookscript", "local:snippets/felhom-guest-hook.sh"}, false, ""},
 	{"guesthook-delete-mp", "dead mountpoint slot delete (C1 net)", "/usr/sbin/pct", []string{"set", "9201", "--delete", "mp0"}, false, ""},
 	{"guest-reboot", "enroll activate-binds reboot", "/usr/sbin/pct", []string{"reboot", "9201"}, false, ""},
+	{"guest-shutdown", "household power-off: guest shutdown (R-998)", "/usr/sbin/pct", []string{"shutdown", "9201", "--timeout", "120"}, false, ""},
+	{"host-poweroff", "household power-off: host power-off (R-998)", "/usr/bin/systemctl", []string{"poweroff"}, false, ""},
+	{"vzdump-partial-clean", "dead half-written vzdump removal (R-1006)", "/usr/local/sbin/felhom-vzdump-partial-clean", []string{"local", "9201", "vzdump-lxc-9201-2026_10_14-04_42_18.tar.dat"}, false, ""},
+	{"internal-place-plan", "internal data place: the size plan (16 §7)", "/usr/local/sbin/felhom-internal-place", []string{"plan", "0"}, false, ""},
+	{"internal-place-create", "internal data place: create on an old box (signed add_internal_place)", "/usr/local/sbin/felhom-internal-place", []string{"create", "0"}, false, ""},
 
 	// ---- LAN split-horizon resolver (dnsmasq) ----
 	{"dnsmasq-install", "dnsmasq package install", "/usr/bin/apt-get", []string{"install", "-y", "-q", "dnsmasq"}, false, ""},

internal/capability/manifest_test.go

@@ -311,3 +311,39 @@ func TestWGCapabilityCriticality(t *testing.T) {
 		}
 	}
 }
+
+// TestEveryAliasIsGranted closes a gap found while adding FELHOM_POWEROFF (R-998): the coverage check above reads
+// every Cmnd_Alias body whether or not the alias appears on the grant line, so a manifest command whose alias was
+// never GRANTED still passed — and failed with „a password is required" on the box. Every defined alias must be
+// named on the `felhom-agent ALL=(root) NOPASSWD:` line. Red-proof: drop FELHOM_POWEROFF from that line.
+func TestEveryAliasIsGranted(t *testing.T) {
+	data, err := os.ReadFile(sudoersPath)
+	if err != nil {
+		t.Fatalf("read sudoers: %v", err)
+	}
+	var defined []string
+	granted := map[string]bool{}
+	grantLines := 0
+	for _, ln := range strings.Split(string(data), "\n") {
+		tr := strings.TrimSpace(ln)
+		if strings.HasPrefix(tr, "Cmnd_Alias ") {
+			if f := strings.Fields(tr); len(f) >= 2 {
+				defined = append(defined, f[1])
+			}
+		}
+		if strings.HasPrefix(tr, "felhom-agent ") && strings.Contains(tr, "NOPASSWD:") {
+			grantLines++
+			for _, a := range strings.Split(tr[strings.Index(tr, "NOPASSWD:")+len("NOPASSWD:"):], ",") {
+				granted[strings.TrimSpace(a)] = true
+			}
+		}
+	}
+	if grantLines == 0 || len(defined) < 10 {
+		t.Fatalf("parsed %d grant line(s), %d aliases — parser broke", grantLines, len(defined))
+	}
+	for _, a := range defined {
+		if !granted[a] {
+			t.Errorf("Cmnd_Alias %s is defined but never granted to felhom-agent", a)
+		}
+	}
+}

internal/capability/r861_injection_test.go

@@ -53,6 +53,30 @@ var r861Injections = []string{
 	"/usr/sbin/pct exec 9201 -- tee /etc/felhom-controller-image",
 	"/usr/local/sbin/felhom-priv-apply controller-image 9201 9202",
 	"/usr/local/sbin/felhom-priv-apply controller-image 9201;id",
+	// R-998 (host power-off): the two new grants take exactly their fixed shape — no extra option, no other target
+	"/usr/sbin/pct shutdown 9201 --timeout 120 --forceStop 1",
+	"/usr/sbin/pct shutdown 9201 --forceStop 1 --timeout 120",
+	"/usr/sbin/pct shutdown 9201",
+	"/usr/sbin/pct shutdown 9201 --timeout -1",
+	"/usr/bin/systemctl poweroff --force",
+	"/usr/bin/systemctl poweroff -ff",
+	"/usr/bin/systemctl reboot",
+	"/usr/bin/systemctl halt",
+	"/usr/bin/systemctl kexec",
+	// R-1006: the partial-cleanup helper takes exactly one storage, one vmid, one half-written name.
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201 vzdump-lxc-9201-2026_10_14-04_42_18.tar.zst",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201 vzdump-lxc-9201-2026_10_14-04_42_18.log",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201 ../../etc/vzdump-lxc-9201-2026_10_14-04_42_18.tar.dat",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201 vzdump-lxc-9201-2026_10_14-04_42_18.tar.dat /etc/shadow",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201 vzdump-lxc-9201-2026_10_14-04_42_18.tar.dat;id",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local;id 9201 vzdump-lxc-9201-2026_10_14-04_42_18.tar.dat",
+	"/usr/local/sbin/felhom-vzdump-partial-clean local 9201",
+	"/usr/local/sbin/felhom-vzdump-partial-clean --help",
+	"/usr/local/sbin/felhom-internal-place create 132",
+	"/usr/local/sbin/felhom-internal-place create 0 extra",
+	"/usr/local/sbin/felhom-internal-place create 0;id",
+	"/usr/local/sbin/felhom-internal-place wipe 0",
+	"/usr/local/sbin/felhom-internal-place create",
 }
 
 func TestSudoersRefusesTheR861Injections(t *testing.T) {

internal/escrow/recover.go

@@ -59,8 +59,26 @@ var (
 	// It carries no material and no code: only WHICH earlier package opened, by its supersession date,
 	// which is the one fact the customer needs to recognise it.
 	ErrCodeOpensRetained = errors.New("escrow: the recovery code did not open the CURRENT sealed package, but it DID open a retained earlier one")
+	// ErrRetainedUnchecked — the code did NOT open the current package, and NOT every earlier package the hub
+	// holds for this host was tried (R-304, 2026-10-08): the retained list could not be fetched, the hub
+	// withheld rows (over its serve cap, or rows with no key material), a package was malformed, or the
+	// attempt cap stopped the loop. So „the code is wrong" is NOT known — it may be right for a package
+	// nobody tried. Distinct from a mistype for exactly the R-224 reason: never accuse the customer of
+	// something we did not check.
+	ErrRetainedUnchecked = errors.New("escrow: the recovery code did not open the current sealed package, and some earlier packages were NOT checked")
 )
 
+// RetainedUncheckedError wraps ErrRetainedUnchecked with how many earlier packages went unchecked
+// (-1 = unknown: the retained list itself could not be read). No secret.
+type RetainedUncheckedError struct {
+	Unchecked int
+}
+
+func (e *RetainedUncheckedError) Error() string {
+	return fmt.Sprintf("%s (unchecked=%d)", ErrRetainedUnchecked.Error(), e.Unchecked)
+}
+func (e *RetainedUncheckedError) Unwrap() error { return ErrRetainedUnchecked }
+
 // RetainedMatch says which retained package a code opened. Returned inside RetainedOpenedError; it
 // carries no secret — not the code, not the bundle, not the repository password.
 type RetainedMatch struct {
@@ -102,8 +120,10 @@ type RetainedBlob struct {
 }
 
 // RetainedFetcher yields this host's RETAINED sealed packages, newest-superseded first. An empty
-// slice is a clean "none". R-311.
-type RetainedFetcher func(ctx context.Context) (blobs []RetainedBlob, unopenable int, err error)
+// slice is a clean "none". R-311. `withheld` counts the earlier packages the hub holds that are NOT in
+// blobs — rows with no key material, rows over the hub's serve cap, and packages dropped as malformed
+// (R-304): each is a package the code was never tried against.
+type RetainedFetcher func(ctx context.Context) (blobs []RetainedBlob, withheld int, err error)
 
 // OffsiteKeyRecoverer is the assembled links 6→8. Construct it with a fetcher; call it with R.
 type OffsiteKeyRecoverer struct {
@@ -154,9 +174,14 @@ func (r OffsiteKeyRecoverer) RecoverOffsiteRepoPassword(ctx context.Context, rec
 		// from the unwrap alone; the only way to tell is to try. Until this existed nobody tried, and
 		// the screen said so out loud ("innen nem tudjuk megkülönböztetni őket") — a true sentence
 		// about our own incuriosity, read by the customer as a statement about their code.
-		if m, ok := r.tryRetained(ctx, recoveryCode); ok {
+		m, ok, unchecked := r.tryRetained(ctx, recoveryCode)
+		if ok {
 			return "", &RetainedOpenedError{Match: m}
 		}
+		// R-304: only when EVERY earlier package the hub holds was tried may this stay a wrong code.
+		if unchecked != 0 {
+			return "", &RetainedUncheckedError{Unchecked: unchecked}
+		}
 		return "", err // the fail-closed "the recovery code did not unwrap…" message; no secret in it
 	}
 	if bundle.ResticRepoPassword == "" {
@@ -173,23 +198,38 @@ func (r OffsiteKeyRecoverer) RecoverOffsiteRepoPassword(ctx context.Context, rec
 // function breaking is the behaviour we had before it existed.
 //
 // NOTHING IS LOGGED HERE and no return value carries the code, a bundle or a password.
-func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode string) (RetainedMatch, bool) {
+//
+// R-304 (2026-10-08): it also returns how many earlier packages were NOT tried — `withheld` from the hub, plus
+// the ones past the attempt cap — or -1 when the retained list could not be read at all. A nil FetchRetained
+// (an agent wired without the lookup) reports 0: the pre-R-311 refusal, unchanged.
+func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode string) (RetainedMatch, bool, int) {
 	if r.FetchRetained == nil {
-		return RetainedMatch{}, false
+		return RetainedMatch{}, false, 0
 	}
-	blobs, _, err := r.FetchRetained(ctx)
-	if err != nil || len(blobs) == 0 {
-		return RetainedMatch{}, false
+	blobs, withheld, err := r.FetchRetained(ctx)
+	if err != nil {
+		return RetainedMatch{}, false, -1
+	}
+	if withheld < 0 {
+		withheld = 0
+	}
+	if len(blobs) == 0 {
+		return RetainedMatch{}, false, withheld
 	}
 	limit := r.MaxRetainedTried
 	if limit <= 0 {
 		limit = defaultMaxRetainedTried
 	}
+	unchecked := withheld
+	if len(blobs) > limit {
+		unchecked += len(blobs) - limit
+	}
 	for i, rb := range blobs {
 		if i >= limit {
 			break
 		}
 		if len(rb.Blob) == 0 {
+			unchecked++
 			continue
 		}
 		bundle, uerr := UnwrapIdentityBundle(ctx, rb.Blob, recoveryCode)
@@ -204,7 +244,7 @@ func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode strin
 			// correct and must be told so — but the history behind it still cannot be reopened, and
 			// saying otherwise would be a promise this path cannot keep.
 			HasResticPassword: bundle.ResticRepoPassword != "",
-		}, true
+		}, true, 0
 	}
-	return RetainedMatch{}, false
+	return RetainedMatch{}, false, unchecked
 }

internal/escrow/recover_retained_test.go

@@ -115,8 +115,9 @@ func TestRecover_WrongCode_StaysAPlainRefusal(t *testing.T) {
 	}
 }
 
-// FAIL-SAFE — if the retained lookup itself fails, the original refusal must stand UNCHANGED. The
-// worst outcome of this feature breaking is the behaviour we had before it.
+// FAIL-SAFE — if the retained lookup itself fails, the lookup's error never reaches the customer and no
+// retained package is claimed. R-304 (2026-10-08) changed what stands instead: not the wrong-code refusal (the
+// earlier packages were never tried, so „wrong" is not known) but ErrRetainedUnchecked with Unchecked = -1.
 //
 // RED-PROOF: make tryRetained propagate the fetch error instead of returning false → the customer
 // gets a new, unexplained failure mode → this FAILS.
@@ -140,6 +141,10 @@ func TestRecover_RetainedFetchFails_OriginalRefusalStands(t *testing.T) {
 	if containsStr(err.Error(), "hub exploded") {
 		t.Error("the retained-lookup failure leaked into the customer-facing refusal — it must be silent")
 	}
+	var ue *RetainedUncheckedError
+	if !errors.As(err, &ue) || ue.Unchecked != -1 {
+		t.Errorf("err = %v, want RetainedUncheckedError{-1} — the earlier packages were never tried (R-304)", err)
+	}
 }
 
 // A nil FetchRetained keeps the pre-R-311 behaviour EXACTLY. An agent wired without it must be
@@ -228,3 +233,72 @@ func containsStr(hay, needle string) bool {
 		return false
 	})()
 }
+
+// ── R-304 (2026-10-08) — „wrong code" only when every earlier package was tried ──────────────────────
+//
+// The consequence asserted: is the refusal a WRONG CODE (the only error the screen may answer with „check your
+// typing")? It may be only when the hub withheld nothing and every served package was tried.
+//
+// RED-PROOF: make tryRetained return 0 for `unchecked` → the three „unchecked" cases return the plain refusal
+// → they FAIL; the all-tried case keeps passing.
+func TestR304_WrongCodeOnlyWhenEveryEarlierPackageWasTried(t *testing.T) {
+	ensureAge(t)
+	current := sealBundle(t, IdentityBundle{ResticRepoPassword: "4444567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	other := sealBundle(t, IdentityBundle{ResticRepoPassword: "5555567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	const code = "a code that opens nothing whatsoever in this test"
+	cases := []struct {
+		name      string
+		blobs     int
+		withheld  int
+		limit     int
+		unchecked int // 0 = must be a plain wrong code
+	}{
+		{"all tried, nothing withheld", 2, 0, 6, 0},
+		{"the hub withheld rows (no key material / over its cap)", 1, 3, 6, 3},
+		{"only withheld rows, nothing served", 0, 2, 6, 2},
+		{"the attempt cap stopped the loop", 5, 0, 2, 3},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			blobs := make([]RetainedBlob, 0, c.blobs)
+			for i := 0; i < c.blobs; i++ {
+				blobs = append(blobs, RetainedBlob{Blob: other, SupersededAt: "2026-08-01 00:00:00", Index: i})
+			}
+			_, err := OffsiteKeyRecoverer{
+				Fetch: fetcherFor(current),
+				FetchRetained: func(context.Context) ([]RetainedBlob, int, error) {
+					return blobs, c.withheld, nil
+				},
+				MaxRetainedTried: c.limit,
+			}.RecoverOffsiteRepoPassword(context.Background(), code)
+			if err == nil {
+				t.Fatal("a code that opens nothing succeeded")
+			}
+			var ue *RetainedUncheckedError
+			isUnchecked := errors.As(err, &ue)
+			if c.unchecked == 0 {
+				if isUnchecked {
+					t.Fatalf("every earlier package was tried — this IS a wrong code, got %v", err)
+				}
+				return
+			}
+			if !isUnchecked || ue.Unchecked != c.unchecked || !errors.Is(err, ErrRetainedUnchecked) {
+				t.Fatalf("err = %v, want RetainedUncheckedError{%d} — never call the code wrong when packages were not tried", err, c.unchecked)
+			}
+		})
+	}
+}
+
+// A malformed (empty) served package counts as not tried.
+func TestR304_EmptyServedPackageCountsAsUnchecked(t *testing.T) {
+	ensureAge(t)
+	current := sealBundle(t, IdentityBundle{ResticRepoPassword: "6666567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	_, err := OffsiteKeyRecoverer{
+		Fetch:         fetcherFor(current),
+		FetchRetained: retainedFetcherFor(RetainedBlob{Blob: nil, SupersededAt: "2026-08-01 00:00:00"}),
+	}.RecoverOffsiteRepoPassword(context.Background(), testR2)
+	var ue *RetainedUncheckedError
+	if !errors.As(err, &ue) || ue.Unchecked != 1 {
+		t.Fatalf("err = %v, want RetainedUncheckedError{1}", err)
+	}
+}

internal/hub/collect.go

@@ -66,6 +66,13 @@ type ProvenRestoreTestReporter interface {
 	ProvenRestoreTests(ctx context.Context) []RestoreTest
 }
 
+// KnownBackupReporter is the newest SUCCESSFUL backup per tier and guest kept on disk (R-894's
+// backup-success-state.json). collectBackups folds it into the report so a restart does not erase the
+// hub's evidence of a backup that ran minutes before it (the kernel-night shape, 2026-10-09).
+type KnownBackupReporter interface {
+	KnownBackupSuccesses() []Backup
+}
+
 // PBSReporter is the slice-6-Phase-B seam the pbs verify loop plugs into (same pattern).
 // Returns the agent's latest-known PBS snapshot inventory + verify-state. nil → empty.
 type PBSReporter interface {
@@ -105,6 +112,7 @@ type Collector struct {
 	backups          BackupReporter
 	restoreTests     RestoreTestReporter
 	provenTests      ProvenRestoreTestReporter
+	knownBackups     KnownBackupReporter // R-894 file → host report after a restart (nil → in-memory only)
 	pbs              PBSReporter
 	temp             TempReader                                    // slice 9: host CPU/chassis temp (nil-safe → nil temp)
 	capProbe         func(ctx context.Context) []capability.Status // v0.44.0: privileged-capability self-check (nil → empty)
@@ -115,6 +123,7 @@ type Collector struct {
 	ctrlSup          ControllerSupervisorReporter                  // R-523: in-guest controller supervisor (nil → stanza omitted)
 	guestNet         GuestNetReporter                              // R-54: per-guest network watchdog (nil → stanza omitted)
 	diskTrim         GuestDiskTrimReporter                         // R-444: weekly guest disk trim (nil → stanza omitted)
+	deliberateOff    func() *DeliberateOff                         // R-998: household power-off record of this boot (nil → omitted)
 	foreignKey       ForeignKeyArchiveReporter                     // R-366 slice 2 (nil → omitted)
 	selfUpdate       SelfUpdateReporter                            // D1: agent self-update pending status (nil → false)
 	mgmtPlane        MgmtPlaneReporter                             // G1: management-plane health (nil → stanza omitted)
@@ -247,6 +256,12 @@ func (c *Collector) SetGuestDiskTrimReporter(r GuestDiskTrimReporter) *Collector
 	return c
 }
 
+// SetDeliberateOffSource wires the R-998 power-off record (poweroff.State.Current, adapted).
+func (c *Collector) SetDeliberateOffSource(f func() *DeliberateOff) *Collector {
+	c.deliberateOff = f
+	return c
+}
+
 // SelfUpdateReporter is the D1 seam the selfupdate commit-manager plugs into (same consumer-side
 // pattern — hub does not import selfupdate). nil (feature not wired) → pending=false on the report.
 type SelfUpdateReporter interface {
@@ -423,6 +438,10 @@ func (c *Collector) Collect(ctx context.Context) (*HostReport, error) {
 	if c.oob != nil {
 		report.OOB = c.oob.OOBStatus(ctx)
 	}
+	// R-998: a household power-off accepted in this boot rides every report until the box is down.
+	if c.deliberateOff != nil {
+		report.DeliberateOff = c.deliberateOff()
+	}
 	return report, nil
 }
 
@@ -576,14 +595,50 @@ func (c *Collector) collectStorage(ctx context.Context) []StorageTarget {
 // collectBackups / collectRestoreTests read the agent's latest backup + restore-test state
 // via the seams. Best-effort: a nil reporter or nil slice degrades to an empty (non-nil)
 // list so the collection always marshals as [].
+//
+// The saved successes (SetKnownBackupReporter) are added for each tier and guest the in-memory list has
+// no success for at or after the saved time. Why: the in-memory list is empty after an agent restart,
+// and the hub's backup-freshness check reads only what the reports carried. Measured 2026-10-09 on
+// demo-felhom: the night backup landed 02:40 UTC, the kernel step restarted the host at 02:44, no report
+// fell in between, so two kernel nights in a row left no trace and the hub alarmed „newest backup is 48h
+// old" at 03:00. Only SUCCESSES are saved, so a failure is never hidden and never invented.
+// Pinned by TestCollectBackups_SavedSuccessSurvivesARestart.
 func (c *Collector) collectBackups(ctx context.Context) []Backup {
-	if c.backups == nil {
-		return []Backup{}
+	out := []Backup{}
+	if c.backups != nil {
+		if b := c.backups.Backups(ctx); b != nil {
+			out = append(out, b...)
+		}
 	}
-	if b := c.backups.Backups(ctx); b != nil {
-		return b
+	if c.knownBackups == nil {
+		return out
 	}
-	return []Backup{}
+	for _, k := range c.knownBackups.KnownBackupSuccesses() {
+		kt, err := time.Parse(time.RFC3339, k.StartedAt)
+		if err != nil {
+			continue
+		}
+		covered := false
+		for _, b := range out {
+			if !b.Success || b.TargetID != k.TargetID || b.VMID != k.VMID {
+				continue
+			}
+			if bt, err := time.Parse(time.RFC3339, b.StartedAt); err == nil && !bt.Before(kt) {
+				covered = true
+				break
+			}
+		}
+		if !covered {
+			out = append(out, k)
+		}
+	}
+	return out
+}
+
+// SetKnownBackupReporter wires the R-894 saved successes into the host report (nil-safe → in-memory only).
+func (c *Collector) SetKnownBackupReporter(r KnownBackupReporter) *Collector {
+	c.knownBackups = r
+	return c
 }
 
 // collectRestoreTests merges the in-memory result with the PERSISTED per-tier proofs (R-189).

internal/hub/collect_knownbackups_test.go

@@ -0,0 +1,62 @@
+package hub
+
+import (
+	"context"
+	"testing"
+)
+
+type fakeMemBackups []Backup
+
+func (f fakeMemBackups) Backups(context.Context) []Backup { return f }
+
+type fakeKnownBackups []Backup
+
+func (f fakeKnownBackups) KnownBackupSuccesses() []Backup { return f }
+
+// The consequence, not the mechanism: after a restart (empty in-memory list) the host report still carries
+// the night's backup, so the hub's freshness check sees it. Measured 2026-10-09 on demo-felhom: without this
+// the report carried backups: [] and the hub alarmed „newest backup is 48h old" an hour after a good backup.
+// RED-PROOF: return before the saved-success loop in collectBackups → the first case reports nothing → fails.
+func TestCollectBackups_SavedSuccessSurvivesARestart(t *testing.T) {
+	saved := Backup{TargetID: "felhom-backup", VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z"}
+
+	t.Run("restart: memory empty, the saved success is reported", func(t *testing.T) {
+		c := &Collector{backups: fakeMemBackups(nil), knownBackups: fakeKnownBackups{saved}}
+		got := c.collectBackups(context.Background())
+		if len(got) != 1 || got[0].StartedAt != saved.StartedAt || !got[0].Success || got[0].TargetID != "felhom-backup" {
+			t.Fatalf("want the saved success, got %+v", got)
+		}
+	})
+
+	t.Run("memory holds the same or a newer success: no second entry", func(t *testing.T) {
+		mem := Backup{TargetID: "felhom-backup", VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z", Archive: "a"}
+		c := &Collector{backups: fakeMemBackups{mem}, knownBackups: fakeKnownBackups{saved}}
+		if got := c.collectBackups(context.Background()); len(got) != 1 || got[0].Archive != "a" {
+			t.Fatalf("want only the in-memory record, got %+v", got)
+		}
+	})
+
+	t.Run("a newer FAILURE in memory never hides the saved success, and is kept", func(t *testing.T) {
+		fail := Backup{TargetID: "felhom-backup", VMID: 9201, Success: false, StartedAt: "2026-10-10T02:40:00Z", Error: "x"}
+		c := &Collector{backups: fakeMemBackups{fail}, knownBackups: fakeKnownBackups{saved}}
+		got := c.collectBackups(context.Background())
+		if len(got) != 2 || got[0].Success || !got[1].Success {
+			t.Fatalf("want the failure and the saved success, got %+v", got)
+		}
+	})
+
+	t.Run("another tier's success does not cover this tier", func(t *testing.T) {
+		other := Backup{TargetID: "felhom-pbs", VMID: 9201, Success: true, StartedAt: "2026-10-10T00:00:00Z"}
+		c := &Collector{backups: fakeMemBackups{other}, knownBackups: fakeKnownBackups{saved}}
+		if got := c.collectBackups(context.Background()); len(got) != 2 {
+			t.Fatalf("want both tiers, got %+v", got)
+		}
+	})
+
+	t.Run("no saved state wired: the in-memory list as before, never nil", func(t *testing.T) {
+		c := &Collector{}
+		if got := c.collectBackups(context.Background()); got == nil || len(got) != 0 {
+			t.Fatalf("want an empty non-nil list, got %#v", got)
+		}
+	})
+}

internal/hub/contract_test.go

@@ -39,11 +39,14 @@ func TestHostReport_ContractMatchesGolden(t *testing.T) {
 				State: StorageStateAttached, Reachable: true, ClassHint: "fast",
 				ThinPool: &ThinPoolFill{DataUsedFraction: 0.42},
 				Smart:    SmartSummary{Health: SmartUnknown},
+				// v0.157.0 (`16` §3): the identity keys ride on both rows so the key-set guard sees them.
+				Kind: "system", PhysicalDisks: []string{"serial:ata:SanDisk_X600:182195804614"}, Identity: "proven",
 			},
 			{
 				Name: "usb-backup", Type: StorageTypeUSB, DurableID: "uuid:x",
 				State: StorageStateAttached, Reachable: true, MountPath: "/mnt/usb-backup", TotalBytes: 2000000000000,
 				Smart: SmartSummary{Health: SmartUnknown},
+				Kind:  "disk", PhysicalDisks: []string{"serial:usb:External:000000000000"}, Identity: "unknown", IdentityReason: "usb_bridge",
 			},
 			// A pbs target so the recipe's pbs coord has a storage.cfg row to resolve its namespace
 			// from (R-106). Without one the fixture produces namespace_state=unknown while the golden

internal/hub/deliberate_off_test.go

@@ -0,0 +1,29 @@
+package hub
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+// R-998: the power-off path waits on SetReportedHook, so the hook must fire only for a report the hub
+// ACCEPTED — a failed push must not let the box power off believing the hub knows.
+func TestLoop_ReportedHookOnlyAfterAcceptedReport(t *testing.T) {
+	var cn, rn int32
+	rep := &HostReport{DeliberateOff: &DeliberateOff{RequestedAt: "2026-10-13T18:00:00Z"}}
+	loop := NewLoop(&fakeCollector{report: rep, n: &cn},
+		&fakeReporter{env: &ControlEnvelope{}, errSeq: []error{errors.New("hub 5xx")}, n: &rn},
+		900*time.Second, quietLogger())
+	var seen []*HostReport
+	loop.SetReportedHook(func(r *HostReport) { seen = append(seen, r) })
+
+	loop.cycle(context.Background(), 900*time.Second) // the push fails
+	if len(seen) != 0 {
+		t.Fatalf("hook fired for a refused report: %d", len(seen))
+	}
+	loop.cycle(context.Background(), 900*time.Second) // the push is accepted
+	if len(seen) != 1 || seen[0].DeliberateOff == nil || seen[0].DeliberateOff.RequestedAt != "2026-10-13T18:00:00Z" {
+		t.Fatalf("hook after an accepted report = %+v", seen)
+	}
+}

internal/hub/loop.go

@@ -66,8 +66,15 @@ type Loop struct {
 	// retry, no duplicate shipping). Loop state is single-goroutine (cycle only).
 	logTailSource  func(maxBytes int) []string
 	logTailPending bool
+
+	// reported (R-998) is called after every report the hub ACCEPTED, with that report. The power-off
+	// path waits on it so the hub has the deliberate-off record before the box goes down.
+	reported func(r *HostReport)
 }
 
+// SetReportedHook wires the R-998 after-report observer. Optional.
+func (l *Loop) SetReportedHook(f func(r *HostReport)) { l.reported = f }
+
 // logTailMaxBytes caps the heartbeat log tail (newest lines kept).
 const logTailMaxBytes = 128 * 1024
 
@@ -156,6 +163,9 @@ func (l *Loop) cycle(ctx context.Context, current time.Duration) time.Duration {
 		l.logger.Warn("hub: report failed; keeping current interval", "err", err)
 		return current
 	}
+	if l.reported != nil {
+		l.reported(report)
+	}
 	if report.LogTail != nil {
 		// Transparency: the pull is visible in the box's own log (and thus in the ring).
 		l.logger.Info("operator log pull served", "component", "agent", "lines", len(report.LogTail.Lines))

internal/hub/report.go

@@ -144,6 +144,12 @@ type HostReport struct {
 	// in the steady state, so the cross-repo host-report golden stays byte-stable.
 	LogTail *LogTail `json:"log_tail,omitempty"`
 
+	// DeliberateOff (R-998, doc 14): the household asked this box to power off, in THIS boot. Present on
+	// every report from the request until the box goes down; absent again after the next boot — that
+	// absence is how the hub learns the box is back. The hub holds its silence alarms while it is set
+	// (14 days). `omitempty`: absent in the steady state, so the cross-repo host-report golden stays stable.
+	DeliberateOff *DeliberateOff `json:"deliberate_off,omitempty"`
+
 	// OOB is the operator-access health stanza (TASK H1). It answers the operator's question — "can I
 	// get into this box right now, and if not, why" — from the hub: felhom-sshd up + on which port,
 	// locally reachable, the tunnel handshake age (the OOB path rides wg-felhom), whether the operator
@@ -425,6 +431,15 @@ type StorageTarget struct {
 	// metadata fill is null until Phase B's privileged `lvs` read.
 	ThinPool *ThinPoolFill `json:"thin_pool,omitempty"`
 
+	// Physical-disk identity (felhom.eu architecture/16-storage-physical-identity.md §3, agent v0.157.0):
+	// the place's kind, the keys of the whole physical disks under it, and whether the agent can prove
+	// them (proven | unknown + identity_reason vm|network|usb_bridge|weak_wwn|no_serial). Agent-computed
+	// from /sys + udev only; empty when not computed (an absent device, an older agent). Additive.
+	Kind           string   `json:"kind,omitempty"`
+	PhysicalDisks  []string `json:"physical_disks,omitempty"`
+	Identity       string   `json:"identity,omitempty"`
+	IdentityReason string   `json:"identity_reason,omitempty"`
+
 	// Smart is the disk-health summary, populated in Phase B via smartctl (sudoers). In
 	// Phase A it is {health:"UNKNOWN", <counters null>} — the keys are committed now so the
 	// contract is stable across both phases.
@@ -636,6 +651,17 @@ type WireOSUpdate struct {
 	// HostRelease is the newest approved HOST release (hub v0.131.0, `11` §8 step 3) — a separate set: a version
 	// approved for the guest is not approved for the host by that fact alone.
 	HostRelease *WireOSRelease `json:"host_release,omitempty"`
+	// Kernel is the kernel lane's instruction for THIS box (R-836, `09` §3 decision 172, `11` §5.11): the kernel the
+	// household was told about, and whether tonight is a told night. Nil (an older hub, or no kernel due) = no kernel
+	// step. The hub sets Tonight only after the household's mail the day before went out — no mail, no step.
+	Kernel *WireKernelStep `json:"kernel,omitempty"`
+}
+
+// WireKernelStep is the hub's kernel-lane instruction (hub osupdates.KernelBlock — field-exact, cross-repo).
+type WireKernelStep struct {
+	Kver       string `json:"kver"`                  // e.g. "7.0.14-22-pve" — the wrapper refuses any other (R23)
+	Tonight    bool   `json:"tonight"`               // the household was mailed the day before: tonight's leg may reboot
+	NotifiedAt string `json:"notified_at,omitempty"` // when that mail went out (RFC 3339), for the log
 }
 
 // WireOSRelease is an approved version set; Snapshot is the approval time (YYYYMMDDTHHMMSSZ) the wrapper uses
@@ -747,3 +773,8 @@ type ForeignKeyArchives struct {
 	Oldest string `json:"oldest"`
 	Newest string `json:"newest"`
 }
+
+// DeliberateOff is the household-requested power-off record (R-998).
+type DeliberateOff struct {
+	RequestedAt string `json:"requested_at"` // RFC3339 UTC, the agent's clock
+}

internal/hub/testdata/host-report.golden.json

@@ -46,6 +46,9 @@
       "backing_device": "",
       "class_hint": "fast",
       "role": "",
+      "kind": "system",
+      "physical_disks": ["serial:ata:SanDisk_X600:182195804614"],
+      "identity": "proven",
       "thin_pool": { "data_used_fraction": 0.42, "metadata_used_fraction": null },
       "smart": {
         "health": "UNKNOWN",
@@ -74,6 +77,10 @@
       "backing_device": "/dev/sdb1",
       "class_hint": "slow",
       "role": "",
+      "kind": "disk",
+      "physical_disks": ["serial:usb:External:000000000000"],
+      "identity": "unknown",
+      "identity_reason": "usb_bridge",
       "smart": {
         "health": "UNKNOWN",
         "temperature_c": null,

internal/localapi/afterbackup_test.go

@@ -15,7 +15,7 @@ import (
 // Red-proof: drop the `b.Success &&` guard and the failed-backup sub-case fails; move the call after release()
 // and the gate sub-case fails.
 func TestAfterPrimaryBackup(t *testing.T) {
-	run := func(t *testing.T, failErr string) (calls []int, gateHeld bool) {
+	run := func(t *testing.T, failErr, path string) (calls []int, gateHeld bool) {
 		gate := &backup.InFlight{}
 		b := &fakeBackups{failErr: failErr}
 		srv := newTestServerS(t, &fakeGuests{}, b, &fakeStore{}, nil)
@@ -34,7 +34,7 @@ func TestAfterPrimaryBackup(t *testing.T) {
 			done <- struct{}{}
 		})
 		h := srv.Handler()
-		if do(t, h, "POST", "/backup", "A", "").Code != http.StatusAccepted {
+		if do(t, h, "POST", path, "A", "").Code != http.StatusAccepted {
 			t.Fatal("POST /backup not accepted")
 		}
 		select {
@@ -47,7 +47,7 @@ func TestAfterPrimaryBackup(t *testing.T) {
 		return calls, gateHeld
 	}
 	t.Run("success runs the leg under the gate", func(t *testing.T) {
-		calls, held := run(t, "")
+		calls, held := run(t, "", "/backup")
 		if len(calls) != 1 {
 			t.Fatalf("the leg ran %d time(s), want 1", len(calls))
 		}
@@ -56,8 +56,21 @@ func TestAfterPrimaryBackup(t *testing.T) {
 		}
 	})
 	t.Run("a failed backup runs nothing", func(t *testing.T) {
-		if calls, _ := run(t, "vzdump exploded"); len(calls) != 0 {
+		if calls, _ := run(t, "vzdump exploded", "/backup"); len(calls) != 0 {
 			t.Fatalf("the leg ran after a FAILED backup: %v", calls)
 		}
 	})
+	// R-899: a household press is not the night's backup — no OS leg after it. Same fake, same successful backup as
+	// the first sub-case; only the query differs. Red-proof: make handleBackup ignore `trigger` and this sub-case
+	// fails with the leg run once.
+	t.Run("a manual press runs nothing", func(t *testing.T) {
+		if calls, _ := run(t, "", "/backup?trigger=manual"); len(calls) != 0 {
+			t.Fatalf("the OS leg ran after a manual press: %v", calls)
+		}
+	})
+	t.Run("the scheduled path with the new query still runs the leg", func(t *testing.T) {
+		if calls, _ := run(t, "", "/backup?trigger=night"); len(calls) != 1 {
+			t.Fatalf("the leg ran %d time(s) after a non-manual backup, want 1", len(calls))
+		}
+	})
 }

internal/localapi/controllersupervisor_test.go

@@ -19,10 +19,10 @@ import (
 // again", and each guard is pinned by the case where acting would be wrong.
 
 type supExec struct {
-	mu        sync.Mutex
-	status    map[int]string // docker .State.Status per vmid; "" = container absent
-	inspectErr error         // non-nil = pct exec itself failed (unknown)
-	restarts  map[int]int
+	mu         sync.Mutex
+	status     map[int]string // docker .State.Status per vmid; "" = container absent
+	inspectErr error          // non-nil = pct exec itself failed (unknown)
+	restarts   map[int]int
 	// onRestart, when set, is the status the container reaches after a restart (a crash-looper
 	// stays "exited").
 	onRestart string
@@ -249,7 +249,6 @@ func TestControllerSupervisorStanza_WireShape(t *testing.T) {
 	}
 }
 
-
 // ---- R-539 (operator ruling 3 of 2026-09-16): the SLOW crash loop ----------------------------------
 
 // supKillOnce kills the controller and lets the supervisor restart it (two confirming sweeps), then

internal/localapi/disks.go

@@ -188,6 +188,13 @@ type DiskInfo struct {
 	// device that exposes no SMART (USB bridge, unread) is ABSENT, not a misleading zero-value UNKNOWN;
 	// the controller feature-detects presence and renders "Nincs adat" when nil (never alarms).
 	Smart *hub.SmartSummary `json:"smart,omitempty"`
+	// Physical-disk identity (v0.157.0, felhom.eu architecture/16-storage-physical-identity.md §3) — the
+	// same agent-computed verdict the hub report carries. Empty when not computed (an absent drive, no
+	// resolver). Additive; an older controller ignores it.
+	Kind           string   `json:"kind,omitempty"`
+	PhysicalDisks  []string `json:"physical_disks,omitempty"`
+	Identity       string   `json:"identity,omitempty"`
+	IdentityReason string   `json:"identity_reason,omitempty"`
 }
 
 // handleDisks lists the host's drives + data-bearing flags (read-only/benign).
@@ -227,6 +234,8 @@ func (s *Server) handleDisks(w http.ResponseWriter, r *http.Request, vmid int) {
 			// really is the target. Reported here so the controller can name the drive in an
 			// absent-target alarm and hide the destructive controls the agent would refuse anyway.
 			BackupTarget: t.Name == primaryTargetID,
+			// `16` §3: copied from the observer, which computed it from /sys + udev.
+			Kind: t.Kind, PhysicalDisks: t.PhysicalDisks, Identity: t.Identity, IdentityReason: t.IdentityReason,
 		}
 		// Intermediary model: the stable in-guest path + whether felhom-data is bound under the parent.
 		// Only user-data /mnt/<name> drives have a guest path (system/backup mounts never cross in).
@@ -398,6 +407,10 @@ func (s *Server) handleDisks(w http.ResponseWriter, r *http.Request, vmid int) {
 						di.Smart = &sm
 					}
 				}
+				// `16` §3: a registry drive's identity, judged on its OWN mount only (never root's).
+				if p, kind, ok := s.ownMountIdentity(d.MountPath); ok {
+					di.Kind, di.PhysicalDisks, di.Identity, di.IdentityReason = kind, p.PhysicalDisks, p.Identity, p.Reason
+				}
 				// R-118: statfs ONLY while the drive's device is present. With the device gone the raw
 				// mountpoint reverts to a bare directory on the ROOT filesystem, and statfs would report
 				// pve-root's size as this drive's (measured: a 4 GB drive advertising 46 GiB). Same trap

internal/localapi/escrow_ceremony.go

@@ -226,6 +226,9 @@ func (s *Server) handleEscrowCeremonyStart(w http.ResponseWriter, r *http.Reques
 	if base == nil {
 		base = context.Background()
 	}
+	// The reply's fields are read HERE, before the job goroutine may write job.Phase (a data race the race
+	// detector caught, 2026-10-13 — the reply could show the finished phase or a torn value).
+	jobID, phase := job.JobID, job.Phase
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
@@ -274,7 +277,7 @@ func (s *Server) handleEscrowCeremonyStart(w http.ResponseWriter, r *http.Reques
 			"claim_ttl_s", int(escrowClaimTTL.Seconds()), "duration_ms", time.Since(start).Milliseconds())
 	}()
 	s.escrowDone = done // tests wait on it; production polls the status endpoint
-	writeStatus(w, http.StatusAccepted, true, map[string]any{"vmid": vmid, "job_id": job.JobID, "phase": job.Phase}, "")
+	writeStatus(w, http.StatusAccepted, true, map[string]any{"vmid": vmid, "job_id": jobID, "phase": phase}, "")
 }
 
 // handleEscrowCeremonyStatus is GET /escrow/ceremony/status: phase + the NON-SECRET summary.

internal/localapi/escrow_recover.go

@@ -127,6 +127,22 @@ func (s *Server) handleRecoverOffsitePassword(w http.ResponseWriter, r *http.Req
 					"retained_has_restic_pw": match.HasResticPassword,
 				},
 				"the recovery code is correct, but it belongs to an EARLIER sealed package (superseded "+match.SupersededAt+"), not the one currently held")
+		// ── R-304 (2026-10-08) — NOT EVERY EARLIER PACKAGE WAS CHECKED. ─────────────────────────
+		//
+		// The current package refused the code, no retained package opened it — and at least one earlier
+		// package the hub holds was never tried (or the list could not be read). Saying „the code is
+		// wrong" here would claim a check that did not happen. 424 (Failed Dependency): the verdict
+		// depends on packages we could not try. The controller classifies on the status, never on this
+		// sentence; an older controller maps an unknown status to its neutral „we do not know why".
+		case errors.Is(err, escrow.ErrRetainedUnchecked):
+			n := -1
+			var ue *escrow.RetainedUncheckedError
+			if errors.As(err, &ue) {
+				n = ue.Unchecked
+			}
+			s.logger.Warn("local-api: offsite key recovery: the code did not open the current package and earlier packages were NOT all checked — not reported as a wrong code (R-304)", "vmid", vmid, "unchecked", n)
+			writeStatus(w, http.StatusFailedDependency, false, map[string]any{"older_unchecked": n},
+				"the recovery code did not open the current sealed package, and earlier packages the hub holds were not all checked — the code may belong to one of them; nothing was written")
 		case errors.Is(err, escrow.ErrNoResticPassword):
 			s.logger.Warn("local-api: offsite key recovery: the bundle opened but predates the repository-password field", "vmid", vmid)
 			writeErr(w, http.StatusConflict, "the recovery code opened the bundle, but it carries NO offsite repository password (sealed before that field existed; it cannot be retro-fitted)")

internal/localapi/escrow_recover_class_test.go

@@ -54,6 +54,13 @@ func TestRecoverOffsitePassword_EachSituationGetsItsOwnStatus(t *testing.T) {
 			wantStatus: 404,
 			mustNotSay: []string{"did not open"},
 		},
+		{
+			// R-304: earlier packages were not all tried — never „did not open the sealed bundle" (the wrong-code words).
+			name:       "earlier packages not all checked — not a wrong code",
+			err:        &escrow.RetainedUncheckedError{Unchecked: 2},
+			wantStatus: 424,
+			mustNotSay: []string{"did not open the sealed bundle", "could not be fetched"},
+		},
 		{
 			name:       "the bundle predates the repository-password field",
 			err:        escrow.ErrNoResticPassword,

internal/localapi/guestbind.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
 )
@@ -104,6 +105,26 @@ func (b *GuestBinder) RebootGuest(ctx context.Context, vmid int) error {
 	return nil
 }
 
+// ShutdownGuest stops the guest cleanly with a time limit (R-998 host power-off, step 2). `pct shutdown`
+// blocks until the guest is down or the limit passes; then it fails and the guest is still running.
+func (b *GuestBinder) ShutdownGuest(ctx context.Context, vmid int, timeout time.Duration) error {
+	secs := int(timeout / time.Second)
+	if secs < 1 {
+		secs = 1
+	}
+	b.logger.Warn("host-poweroff: shutting the guest down", "vmid", vmid, "timeout_s", secs)
+	if err := b.run(ctx, "pct", "shutdown", strconv.Itoa(vmid), "--timeout", strconv.Itoa(secs)); err != nil {
+		return fmt.Errorf("host-poweroff: pct shutdown %d: %w", vmid, err)
+	}
+	return nil
+}
+
+// PowerOffHost powers the Proxmox host off (R-998, step 3). The one fixed vector `/usr/bin/systemctl poweroff`.
+func (b *GuestBinder) PowerOffHost(ctx context.Context) error {
+	b.logger.Warn("host-poweroff: powering the host off")
+	return b.run(ctx, "/usr/bin/systemctl", "poweroff")
+}
+
 func (b *GuestBinder) run(ctx context.Context, name string, args ...string) error {
 	_, stderr, err := b.runner.Run(ctx, name, args...)
 	if err != nil {

internal/localapi/hostpoweroff.go

@@ -0,0 +1,362 @@
+package localapi
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/poweroff"
+)
+
+// ── POST /host/poweroff (R-998, documentation/architecture/14-host-power-off.md) ──────────────────────
+//
+// The household's „A gép kikapcsolása": shut THIS guest down cleanly, then power the whole host off. The
+// first local-API route whose effect reaches beyond the caller's own guest — a compromised controller can
+// now switch the box off, and nobody can switch it on remotely. The mitigations are the limits below:
+//
+//   - refused in the first 10 minutes after boot (no power-off loop);
+//   - at most ONE accepted request per boot (poweroff.State, persisted, keyed by the boot);
+//   - refused while a backup, restore test, OS update step, controller update, drive format, NAS verify
+//     or escrow ceremony runs, or a vzdump of the guest is in flight — each named in the 409;
+//   - refused while ANY OTHER guest or VM runs on the host (security review 2026-10-13): one guest's
+//     controller must not switch off another household's guest, a scratch guest or a test VM (demo-hp
+//     carries the Tester 1 VM). Read from /proc (`lxc-start -n N`, `kvm -id N`), fail closed;
+//   - the heavy-operation gate is TAKEN on acceptance and never given back (the box is going down), so no
+//     backup, restore test or OS step can start between the checks and the power-off (security review).
+//     Released only if the power-off command itself fails.
+//
+// Every check fails CLOSED: an unwired gate, an unreadable task list or /proc refuses.
+// On acceptance the record is written FIRST, the hub is given a report carrying it (bounded wait), and
+// only then: guest shutdown (time-limited), host power-off. Pinned by hostpoweroff_test.go.
+
+// HostPowerer is the privileged half: both run as fixed sudo vectors (configs/felhom-agent.sudoers).
+type HostPowerer interface {
+	ShutdownGuest(ctx context.Context, vmid int, timeout time.Duration) error
+	PowerOffHost(ctx context.Context) error
+}
+
+// HostPowerOffConfig wires the route. A nil config leaves it answering 503.
+type HostPowerOffConfig struct {
+	State     *poweroff.State
+	Power     HostPowerer
+	ReportNow func(ctx context.Context) bool // push a report carrying the record; true = the hub accepted it
+	Uptime    func() (time.Duration, bool)   // time since host boot; false = unknown (refuse)
+	Running   func() ([]int, error)          // vmids of every running guest and VM on the host; default /proc
+	MinUptime time.Duration                  // default 10 min
+	GuestStop time.Duration                  // pct shutdown --timeout; default 120 s
+	ReportMax time.Duration                  // longest wait for the hub; default 60 s
+	JobWait   time.Duration                  // longest wait for a job that started after acceptance; default 15 min
+	JobPoll   time.Duration                  // how often that wait looks again; default 10 s
+	Now       func() time.Time
+}
+
+// Refusal codes — the controller maps each to a household sentence. Stable wire values.
+const (
+	PowerOffTooSoon      = "too_soon_after_boot"
+	PowerOffAlreadyAsked = "already_requested_this_boot"
+	PowerOffBackup       = "backup_running"
+	PowerOffRestoreTest  = "restore_test_running"
+	PowerOffOSUpdate     = "os_update_running"
+	PowerOffCtrlUpdate   = "controller_update_running"
+	PowerOffDrive        = "drive_operation_running"
+	PowerOffEscrow       = "escrow_ceremony_running"
+	PowerOffBusy         = "host_busy"
+	PowerOffOtherGuests  = "other_guests_running"
+	PowerOffUnknown      = "state_unknown"
+)
+
+// SetHostPowerOff enables POST /host/poweroff.
+func (s *Server) SetHostPowerOff(c HostPowerOffConfig) {
+	if c.MinUptime == 0 {
+		c.MinUptime = 10 * time.Minute
+	}
+	if c.GuestStop == 0 {
+		c.GuestStop = 120 * time.Second
+	}
+	if c.ReportMax == 0 {
+		c.ReportMax = 60 * time.Second
+	}
+	if c.Now == nil {
+		c.Now = time.Now
+	}
+	if c.JobWait == 0 {
+		c.JobWait = 15 * time.Minute
+	}
+	if c.JobPoll == 0 {
+		c.JobPoll = 10 * time.Second
+	}
+	if c.Running == nil {
+		c.Running = func() ([]int, error) { return runningGuestsFromProc("/proc") }
+	}
+	s.powerOff = &c
+}
+
+type hostPowerOffRequest struct {
+	VMID int `json:"vmid"`
+}
+
+func (s *Server) handleHostPowerOff(w http.ResponseWriter, r *http.Request, vmid int) {
+	c := s.powerOff
+	if c == nil || c.State == nil || c.Power == nil {
+		writeErr(w, http.StatusServiceUnavailable, "host power-off not configured on this host")
+		return
+	}
+	if r.ContentLength != 0 {
+		var req hostPowerOffRequest
+		if !decodeBody(w, r, &req) {
+			return
+		}
+		if !s.scopedFromBody(w, req.VMID, vmid, r.URL.Path) {
+			return
+		}
+	}
+	// One decision at a time: two requests racing must not both pass the guards before either marks.
+	s.powerOffMu.Lock()
+	defer s.powerOffMu.Unlock()
+	if code, detail := s.powerOffBlocker(r.Context(), vmid); code != "" {
+		s.logger.Info("local-api: host power-off refused", "vmid", vmid, "reason", code, "detail", detail)
+		writeStatus(w, http.StatusConflict, false, map[string]any{"reason": code, "detail": detail}, "host power-off refused: "+code)
+		return
+	}
+	// Take the heavy-operation gate for good: nothing heavy may start between these checks and the power-off.
+	release, busy, free := s.inFlight.TryAcquire("host-poweroff")
+	if !free {
+		writeStatus(w, http.StatusConflict, false, map[string]any{"reason": PowerOffBusy, "detail": busy}, "host power-off refused: "+PowerOffBusy)
+		return
+	}
+	rec, err := c.State.Mark(c.Now(), vmid)
+	if err != nil {
+		release()
+		code := PowerOffUnknown
+		if errors.Is(err, poweroff.ErrAlreadyThisBoot) {
+			code = PowerOffAlreadyAsked
+		}
+		s.logger.Warn("local-api: host power-off refused (record)", "vmid", vmid, "reason", code, "err", err)
+		writeStatus(w, http.StatusConflict, false, map[string]any{"reason": code, "detail": err.Error()}, "host power-off refused: "+code)
+		return
+	}
+	s.logger.Warn("local-api: HOST POWER-OFF accepted (household request)", "vmid", vmid,
+		"requested_at", rec.RequestedAt.Format(time.RFC3339))
+	base := s.baseCtx
+	if base == nil {
+		base = context.Background()
+	}
+	go s.runHostPowerOff(base, vmid, release)
+	writeStatus(w, http.StatusAccepted, true, map[string]any{
+		"vmid": vmid, "powering_off": true, "requested_at": rec.RequestedAt.Format(time.RFC3339),
+	}, "")
+}
+
+// runHostPowerOff: hub first (bounded), then the guest (time-limited), then the host. A failed guest
+// shutdown does not stop the power-off — the household asked for it, and Proxmox's own shutdown stops
+// any guest still running (pve-guests) before the host goes down.
+func (s *Server) runHostPowerOff(base context.Context, vmid int, release func()) {
+	c := s.powerOff
+	if c.ReportNow != nil {
+		ctx, cancel := context.WithTimeout(base, c.ReportMax)
+		ok := c.ReportNow(ctx)
+		cancel()
+		s.logger.Warn("host-poweroff: step 1/3 — hub told", "vmid", vmid, "hub_accepted", ok)
+	}
+	if !s.waitJobsClear(base, vmid, "before the guest shutdown") {
+		release()
+		return
+	}
+	start := time.Now()
+	ctx, cancel := context.WithTimeout(base, c.GuestStop+60*time.Second)
+	err := c.Power.ShutdownGuest(ctx, vmid, c.GuestStop)
+	cancel()
+	if err != nil {
+		s.logger.Error("host-poweroff: step 2/3 — guest shutdown failed; powering off anyway", "vmid", vmid,
+			"took", time.Since(start).Round(time.Second), "err", err)
+	} else {
+		s.logger.Warn("host-poweroff: step 2/3 — guest stopped", "vmid", vmid, "took", time.Since(start).Round(time.Second))
+	}
+	if !s.waitJobsClear(base, vmid, "before the host power-off") {
+		release()
+		return
+	}
+	s.logger.Warn("host-poweroff: step 3/3 — powering the host off")
+	ctx, cancel = context.WithTimeout(base, 60*time.Second)
+	defer cancel()
+	if err := c.Power.PowerOffHost(ctx); err != nil {
+		s.logger.Error("host-poweroff: host power-off command failed — heavy-operation gate released", "err", err)
+		release()
+	}
+}
+
+// powerOffBlocker returns the first reason to refuse ("" = none) and a detail for the log/operator.
+func (s *Server) powerOffBlocker(ctx context.Context, vmid int) (string, string) {
+	c := s.powerOff
+	if c.State.Current() != nil {
+		return PowerOffAlreadyAsked, "a power-off was already accepted in this boot"
+	}
+	if c.Uptime == nil {
+		return PowerOffUnknown, "uptime not wired"
+	}
+	up, ok := c.Uptime()
+	if !ok {
+		return PowerOffUnknown, "cannot read the host uptime"
+	}
+	if up < c.MinUptime {
+		return PowerOffTooSoon, "host up " + up.Round(time.Second).String() + ", minimum " + c.MinUptime.String()
+	}
+	if s.inFlight == nil || s.staleLock == nil {
+		return PowerOffUnknown, "the heavy-operation gate or the Proxmox task reader is not wired"
+	}
+	if code, detail := s.otherGuestsBlocker(vmid); code != "" {
+		return code, detail
+	}
+	if busy := s.inFlight.Busy(); busy != "" {
+		switch {
+		case strings.HasPrefix(busy, "backup:"):
+			return PowerOffBackup, busy
+		case busy == "restore-test":
+			return PowerOffRestoreTest, busy
+		case strings.HasPrefix(busy, "os-"):
+			return PowerOffOSUpdate, busy
+		default:
+			return PowerOffBusy, busy
+		}
+	}
+	return s.jobBlocker(ctx, vmid)
+}
+
+// jobBlocker is the part of the checks that can change after acceptance — a backup job, a controller update, a drive
+// or NAS job, an escrow ceremony, a Proxmox vzdump. runHostPowerOff asks it again before each step (security review
+// 2026-10-13: the checks ran only once). The heavy-operation gate is not here: the power-off holds it.
+func (s *Server) jobBlocker(ctx context.Context, vmid int) (string, string) {
+	s.jobsMu.Lock()
+	for k, j := range s.jobs {
+		if j != nil && backupInFlight(j.Phase) {
+			s.jobsMu.Unlock()
+			return PowerOffBackup, "backup job " + j.JobID + " on target " + k.target
+		}
+	}
+	s.jobsMu.Unlock()
+	s.swapMu.Lock()
+	for v, on := range s.swapInFlight {
+		if on {
+			s.swapMu.Unlock()
+			return PowerOffCtrlUpdate, "controller swap in flight for guest " + strconv.Itoa(v)
+		}
+	}
+	s.swapMu.Unlock()
+	if s.formatJobs != nil {
+		if j := s.formatJobs.get(); j != nil && j.Phase == formatPhaseRunning {
+			return PowerOffDrive, "drive format running"
+		}
+	}
+	s.netVerifyMu.Lock()
+	nv := s.netVerifyCur != nil && s.netVerifyCur.Phase == netVerifyPhaseRunning
+	s.netVerifyMu.Unlock()
+	if nv {
+		return PowerOffDrive, "network storage verify running"
+	}
+	s.escrowMu.Lock()
+	esc := s.escrowJob != nil && s.escrowJob.Phase == escrowPhaseRunning
+	s.escrowMu.Unlock()
+	if esc {
+		return PowerOffEscrow, "escrow ceremony running"
+	}
+	vz, err := s.staleLock.BackupRunning(ctx, vmid)
+	if err != nil {
+		return PowerOffUnknown, "cannot list running Proxmox tasks: " + err.Error()
+	}
+	if vz {
+		return PowerOffBackup, "vzdump running for guest " + strconv.Itoa(vmid)
+	}
+	return "", ""
+}
+
+// runningGuestsFromProc lists the vmids of running containers (`lxc-start … -n N`) and VMs (`kvm -id N`) from
+// the process table — readable by the non-root agent, unlike /run/qemu-server (measured on demo-hp 2026-10-13).
+// An unreadable /proc is an error (fail closed); an unreadable single process is skipped (it exited).
+func runningGuestsFromProc(procDir string) ([]int, error) {
+	ents, err := os.ReadDir(procDir)
+	if err != nil {
+		return nil, err
+	}
+	seen := map[int]bool{}
+	var out []int
+	for _, e := range ents {
+		if _, err := strconv.Atoi(e.Name()); err != nil {
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(procDir, e.Name(), "cmdline"))
+		if err != nil || len(raw) == 0 {
+			continue
+		}
+		args := strings.Split(strings.TrimRight(string(raw), "\x00"), "\x00")
+		flag := ""
+		switch filepath.Base(args[0]) {
+		case "lxc-start":
+			flag = "-n"
+		case "kvm", "qemu-system-x86_64":
+			flag = "-id"
+		default:
+			continue
+		}
+		for i := 1; i+1 < len(args); i++ {
+			if args[i] == flag {
+				if v, err := strconv.Atoi(args[i+1]); err == nil && !seen[v] {
+					seen[v] = true
+					out = append(out, v)
+				}
+			}
+		}
+	}
+	return out, nil
+}
+
+// otherGuestsBlocker refuses while any guest or VM other than the caller's runs (or the list cannot be read).
+func (s *Server) otherGuestsBlocker(vmid int) (string, string) {
+	running, err := s.powerOff.Running()
+	if err != nil {
+		return PowerOffUnknown, "cannot list the running guests: " + err.Error()
+	}
+	var others []string
+	for _, v := range running {
+		if v != vmid {
+			others = append(others, strconv.Itoa(v))
+		}
+	}
+	if len(others) > 0 {
+		return PowerOffOtherGuests, "other guests or VMs running: " + strings.Join(others, ", ")
+	}
+	return "", ""
+}
+
+// waitJobsClear waits until jobBlocker finds nothing, at most JobWait. false = still busy (or unreadable) at the end:
+// the power-off is CANCELLED — the box stays on, the gate is released, the log says why. Better a box that did not
+// switch off than a backup, update or format cut in the middle.
+func (s *Server) waitJobsClear(base context.Context, vmid int, when string) bool {
+	c := s.powerOff
+	ctx, cancel := context.WithTimeout(base, c.JobWait)
+	defer cancel()
+	for {
+		// Another guest or VM started after acceptance (security review 2026-10-13): no waiting — cancel at once.
+		if code, detail := s.otherGuestsBlocker(vmid); code != "" {
+			s.logger.Error("host-poweroff: CANCELLED — another guest is running now; the box stays on", "when", when,
+				"reason", code, "detail", detail)
+			return false
+		}
+		code, detail := s.jobBlocker(ctx, vmid)
+		if code == "" {
+			return true
+		}
+		s.logger.Warn("host-poweroff: waiting — a job started after the request", "when", when, "reason", code, "detail", detail)
+		select {
+		case <-ctx.Done():
+			s.logger.Error("host-poweroff: CANCELLED — still busy after the wait; the box stays on", "when", when,
+				"reason", code, "detail", detail, "waited", c.JobWait)
+			return false
+		case <-time.After(c.JobPoll):
+		}
+	}
+}

internal/localapi/hostpoweroff_test.go

@@ -0,0 +1,353 @@
+package localapi
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/backup"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/poweroff"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// fakePower records the power-off steps in order.
+type fakePower struct {
+	mu    sync.Mutex
+	steps []string
+}
+
+func (f *fakePower) ShutdownGuest(_ context.Context, vmid int, timeout time.Duration) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.steps = append(f.steps, "shutdown:"+itoaT(vmid)+":"+timeout.String())
+	return nil
+}
+func (f *fakePower) PowerOffHost(context.Context) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.steps = append(f.steps, "poweroff")
+	return nil
+}
+func (f *fakePower) got() []string {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return append([]string(nil), f.steps...)
+}
+
+func itoaT(n int) string { b, _ := json.Marshal(n); return string(b) }
+
+type fakeVzdump struct{ running bool }
+
+func (f fakeVzdump) Guests(context.Context) ([]proxmox.Guest, error)      { return nil, nil }
+func (f fakeVzdump) Lock(context.Context, int) (string, bool, error)      { return "", true, nil }
+func (f fakeVzdump) BackupRunning(context.Context, int) (bool, error)     { return f.running, nil }
+func (f fakeVzdump) Unlock(context.Context, int) error                    { return nil }
+func (f fakeVzdump) Start(context.Context, int) error                     { return nil }
+func (f fakeVzdump) HasVzdumpSnapshot(context.Context, int) (bool, error) { return false, nil }
+func (f fakeVzdump) DeleteVzdumpSnapshot(context.Context, int) error      { return nil }
+
+type powerRig struct {
+	srv    *Server
+	h      http.Handler
+	power  *fakePower
+	state  *poweroff.State
+	report *[]string
+}
+
+func newPowerRig(t *testing.T, uptime time.Duration) *powerRig {
+	t.Helper()
+	srv := newTestServerS(t, &fakeGuests{}, &fakeBackups{}, &fakeStore{}, nil)
+	srv.inFlight = &backup.InFlight{}
+	srv.staleLock = fakeVzdump{}
+	p := &fakePower{}
+	st := poweroff.New(filepath.Join(t.TempDir(), "poweroff.json"), func() string { return "1700000000" })
+	var reports []string
+	srv.SetHostPowerOff(HostPowerOffConfig{
+		State: st,
+		Power: p,
+		ReportNow: func(context.Context) bool {
+			// The record must already exist when the hub is told — that is the point of telling it.
+			if st.Current() == nil {
+				reports = append(reports, "report-without-record")
+			} else if len(p.got()) != 0 {
+				reports = append(reports, "report-after-"+p.got()[0])
+			} else {
+				reports = append(reports, "report")
+			}
+			return true
+		},
+		Uptime:  func() (time.Duration, bool) { return uptime, true },
+		Running: func() ([]int, error) { return []int{8200}, nil },
+		Now:     func() time.Time { return testNow },
+	})
+	return &powerRig{srv: srv, h: srv.Handler(), power: p, state: st, report: &reports}
+}
+
+func (r *powerRig) waitSteps(t *testing.T, n int) []string {
+	t.Helper()
+	for i := 0; i < 200 && len(r.power.got()) < n; i++ {
+		time.Sleep(time.Millisecond)
+	}
+	return r.power.got()
+}
+
+func reasonOf(t *testing.T, body []byte) string {
+	t.Helper()
+	var resp struct {
+		Data struct {
+			Reason string `json:"reason"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(body, &resp); err != nil {
+		t.Fatalf("body %s: %v", body, err)
+	}
+	return resp.Data.Reason
+}
+
+// The whole path: 202, the record written, the hub told FIRST, then guest shutdown (120 s), then host off.
+func TestHostPowerOff_AcceptedOrder(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusAccepted {
+		t.Fatalf("got %d want 202 (%s)", w.Code, w.Body.String())
+	}
+	steps := r.waitSteps(t, 2)
+	want := []string{"shutdown:8200:2m0s", "poweroff"}
+	if len(steps) != 2 || steps[0] != want[0] || steps[1] != want[1] {
+		t.Fatalf("steps = %v, want %v", steps, want)
+	}
+	// The heavy-operation gate stays taken: no backup can start between the checks and the power-off.
+	if _, busy, ok := r.srv.inFlight.TryAcquire("backup:primary"); ok || busy != "host-poweroff" {
+		t.Fatalf("after acceptance a backup could take the gate (ok=%v busy=%q)", ok, busy)
+	}
+	if len(*r.report) != 1 || (*r.report)[0] != "report" {
+		t.Fatalf("hub report = %v, want one report carrying the record", *r.report)
+	}
+	if rec := r.state.Current(); rec == nil || rec.VMID != 8200 {
+		t.Fatalf("record = %+v", rec)
+	}
+}
+
+// Refused during a backup — the shared heavy-operation gate held by a backup tier.
+func TestHostPowerOff_RefusedDuringBackup(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	release, _, ok := r.srv.inFlight.TryAcquire("backup:primary")
+	if !ok {
+		t.Fatal("could not hold the gate")
+	}
+	defer release()
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffBackup {
+		t.Fatalf("got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffBackup)
+	}
+	time.Sleep(5 * time.Millisecond)
+	if s := r.power.got(); len(s) != 0 {
+		t.Fatalf("power steps ran during a backup: %v", s)
+	}
+	if r.state.Current() != nil {
+		t.Fatal("a refused request must not use up the boot's one request")
+	}
+	// The same guard names a restore test and an OS step.
+	release()
+	for gate, want := range map[string]string{"restore-test": PowerOffRestoreTest, "os-pve-step": PowerOffOSUpdate} {
+		rel, _, _ := r.srv.inFlight.TryAcquire(gate)
+		w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+		rel()
+		if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != want {
+			t.Fatalf("%s: got %d %s, want 409 %s", gate, w.Code, w.Body.String(), want)
+		}
+	}
+}
+
+// A vzdump of the guest in flight (a Proxmox task, not the agent's own gate) refuses too.
+func TestHostPowerOff_RefusedDuringVzdump(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	r.srv.staleLock = fakeVzdump{running: true}
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffBackup {
+		t.Fatalf("got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffBackup)
+	}
+}
+
+// One accepted request per boot: the second is refused and nothing runs twice.
+func TestHostPowerOff_SecondRequestSameBootRefused(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	if w := do(t, r.h, "POST", "/host/poweroff", "A", ""); w.Code != http.StatusAccepted {
+		t.Fatalf("first: %d", w.Code)
+	}
+	r.waitSteps(t, 2)
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffAlreadyAsked {
+		t.Fatalf("second: got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffAlreadyAsked)
+	}
+	time.Sleep(5 * time.Millisecond)
+	if s := r.power.got(); len(s) != 2 {
+		t.Fatalf("steps = %v, want exactly one run", s)
+	}
+}
+
+// Refused in the first 10 minutes after boot; an unknown uptime refuses too (fail closed).
+func TestHostPowerOff_TooSoonAfterBoot(t *testing.T) {
+	r := newPowerRig(t, 9*time.Minute)
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffTooSoon {
+		t.Fatalf("got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffTooSoon)
+	}
+	r.srv.powerOff.Uptime = func() (time.Duration, bool) { return 0, false }
+	w = do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffUnknown {
+		t.Fatalf("unknown uptime: got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffUnknown)
+	}
+}
+
+// Not configured → 503; another guest's vmid in the body → 403; no token → 401.
+func TestHostPowerOff_ScopeAndConfig(t *testing.T) {
+	plain := newTestServer(t, &fakeGuests{}, &fakeBackups{}, &fakeStore{}, nil)
+	if w := do(t, plain, "POST", "/host/poweroff", "A", ""); w.Code != http.StatusServiceUnavailable {
+		t.Fatalf("unconfigured: %d", w.Code)
+	}
+	r := newPowerRig(t, time.Hour)
+	if w := do(t, r.h, "POST", "/host/poweroff", "A", `{"vmid":9300}`); w.Code != http.StatusForbidden {
+		t.Fatalf("cross-guest: %d", w.Code)
+	}
+	if w := do(t, r.h, "POST", "/host/poweroff", "", ""); w.Code != http.StatusUnauthorized {
+		t.Fatalf("no token: %d", w.Code)
+	}
+	if r.state.Current() != nil || len(r.power.got()) != 0 {
+		t.Fatal("a refused request changed state")
+	}
+}
+
+// Another guest or VM on the host refuses: one controller must not switch off someone else's guest (security
+// review 2026-10-13; demo-hp runs a scratch guest and the Tester 1 VM). An unreadable process list refuses too.
+func TestHostPowerOff_RefusedWhileOtherGuestsRun(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	r.srv.powerOff.Running = func() ([]int, error) { return []int{8200, 9202, 341}, nil }
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffOtherGuests {
+		t.Fatalf("got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffOtherGuests)
+	}
+	r.srv.powerOff.Running = func() ([]int, error) { return nil, errors.New("no /proc") }
+	w = do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffUnknown {
+		t.Fatalf("unreadable: got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffUnknown)
+	}
+	if len(r.power.got()) != 0 || r.state.Current() != nil {
+		t.Fatal("a refused request changed state")
+	}
+}
+
+// Fail closed: an unwired vzdump reader refuses instead of skipping the check.
+func TestHostPowerOff_FailsClosedWithoutTaskReader(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	r.srv.staleLock = nil
+	w := do(t, r.h, "POST", "/host/poweroff", "A", "")
+	if w.Code != http.StatusConflict || reasonOf(t, w.Body.Bytes()) != PowerOffUnknown {
+		t.Fatalf("got %d %s, want 409 %s", w.Code, w.Body.String(), PowerOffUnknown)
+	}
+}
+
+// The /proc reader finds containers and VMs by their real command lines (as measured on demo-hp).
+func TestRunningGuestsFromProc(t *testing.T) {
+	dir := t.TempDir()
+	write := func(pid, cmd string) {
+		_ = os.MkdirAll(filepath.Join(dir, pid), 0o755)
+		_ = os.WriteFile(filepath.Join(dir, pid, "cmdline"), []byte(strings.ReplaceAll(cmd, " ", "\x00")+"\x00"), 0o644)
+	}
+	write("1927", "/usr/bin/lxc-start -F -n 9201")
+	write("1900", "/usr/bin/lxc-start -F -n 9202")
+	write("1823", "/usr/bin/kvm -id 341 -name night1004-tester1 -no-shutdown")
+	write("974", "/usr/libexec/lxc/lxc-monitord --daemon")
+	write("50", "/usr/bin/bash -c echo -n 5")
+	_ = os.MkdirAll(filepath.Join(dir, "self"), 0o755)
+	got, err := runningGuestsFromProc(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	sort.Ints(got)
+	if len(got) != 3 || got[0] != 341 || got[1] != 9201 || got[2] != 9202 {
+		t.Fatalf("got %v, want [341 9201 9202]", got)
+	}
+	if _, err := runningGuestsFromProc(filepath.Join(dir, "missing")); err == nil {
+		t.Fatal("an unreadable /proc must be an error")
+	}
+}
+
+// switchVzdump is a vzdump reader the test can flip while the power-off runs.
+type switchVzdump struct {
+	fakeVzdump
+	on *atomic.Bool
+}
+
+func (f switchVzdump) BackupRunning(context.Context, int) (bool, error) { return f.on.Load(), nil }
+
+// A job that starts AFTER acceptance (security review 2026-10-13): the power-off waits; if the job is still running
+// when the wait ends, the power-off is cancelled — no guest shutdown, no host power-off, the gate given back.
+func TestHostPowerOff_JobStartedAfterAcceptance(t *testing.T) {
+	// (a) it clears during the wait → the power-off goes ahead after it
+	r := newPowerRig(t, time.Hour)
+	var on atomic.Bool
+	r.srv.staleLock = switchVzdump{on: &on}
+	r.srv.powerOff.JobWait, r.srv.powerOff.JobPoll = 2*time.Second, 2*time.Millisecond
+	r.srv.powerOff.ReportNow = func(context.Context) bool { on.Store(true); return true } // a vzdump starts now
+	if w := do(t, r.h, "POST", "/host/poweroff", "A", ""); w.Code != http.StatusAccepted {
+		t.Fatalf("accept: %d %s", w.Code, w.Body.String())
+	}
+	time.Sleep(30 * time.Millisecond)
+	if s := r.power.got(); len(s) != 0 {
+		t.Fatalf("a step ran while the vzdump ran: %v", s)
+	}
+	on.Store(false)
+	if s := r.waitSteps(t, 2); len(s) != 2 {
+		t.Fatalf("after the vzdump ended the steps = %v, want shutdown + poweroff", s)
+	}
+
+	// (b) it never clears → cancelled, nothing switched off, the heavy gate free again
+	r2 := newPowerRig(t, time.Hour)
+	var on2 atomic.Bool
+	r2.srv.staleLock = switchVzdump{on: &on2}
+	r2.srv.powerOff.JobWait, r2.srv.powerOff.JobPoll = 40*time.Millisecond, 2*time.Millisecond
+	r2.srv.powerOff.ReportNow = func(context.Context) bool { on2.Store(true); return true }
+	if w := do(t, r2.h, "POST", "/host/poweroff", "A", ""); w.Code != http.StatusAccepted {
+		t.Fatalf("accept: %d", w.Code)
+	}
+	time.Sleep(150 * time.Millisecond)
+	if s := r2.power.got(); len(s) != 0 {
+		t.Fatalf("cancelled power-off still ran: %v", s)
+	}
+	if busy := r2.srv.inFlight.Busy(); busy != "" {
+		t.Fatalf("the heavy gate is still held after a cancel: %q", busy)
+	}
+}
+
+// A guest or VM started AFTER acceptance cancels the power-off at once (security review 2026-10-13).
+func TestHostPowerOff_OtherGuestStartedAfterAcceptance(t *testing.T) {
+	r := newPowerRig(t, time.Hour)
+	var started atomic.Bool
+	r.srv.powerOff.Running = func() ([]int, error) {
+		if started.Load() {
+			return []int{8200, 341}, nil
+		}
+		return []int{8200}, nil
+	}
+	r.srv.powerOff.ReportNow = func(context.Context) bool { started.Store(true); return true } // a VM starts now
+	if w := do(t, r.h, "POST", "/host/poweroff", "A", ""); w.Code != http.StatusAccepted {
+		t.Fatalf("accept: %d %s", w.Code, w.Body.String())
+	}
+	time.Sleep(50 * time.Millisecond)
+	if s := r.power.got(); len(s) != 0 {
+		t.Fatalf("power-off ran although a VM started: %v", s)
+	}
+	if busy := r.srv.inFlight.Busy(); busy != "" {
+		t.Fatalf("the heavy gate is still held after a cancel: %q", busy)
+	}
+}

internal/localapi/internalplace.go

@@ -0,0 +1,207 @@
+package localapi
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"sync"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
+)
+
+// The internal data place („Belső tárhely", agent v0.158.0) — felhom.eu architecture/16-storage-physical-identity.md
+// §5, §7. On a one-disk box the root helper configs/felhom-internal-place makes a second thin volume in local-lvm
+// (<vg>/felhom-belso, ext4, label felhom-belso). The installer (a new box) or the signed add_internal_place job (an old
+// box) then writes InternalPlaceRecord to the agent's state dir. From then on the agent treats the volume exactly like
+// an enrolled drive: a Felhom mount unit by fs-UUID at /mnt/belso (EnsureMount), the `enrolled` intent, and — when the
+// controller asks with its own token (POST /disks/guest-attach) — the bind at /mnt/felhom-drives/belso. So it is a
+// HOST mount under the guest's mp8 parent: not in the guest config, not in vzdump, not in PBS (`16` §5).
+//
+// What it is NOT: a drive the household can format, wipe, eject or decommission. Its device is a device-mapper volume
+// on the system disk, so the role gate (roleForMountPath → system) and the format path (ValidateBlockDevice refuses
+// dm) refuse all four — pinned by internalplace_test.go. Its identity is the system disk's (build A), so a Tier-2 copy
+// between it and sys_drive is never a second copy.
+const (
+	InternalPlaceName  = "belso"
+	InternalPlaceWhere = "/mnt/belso"
+	// InternalPlaceFile is the record's name inside the agent's state dir.
+	InternalPlaceFile = "internal-place.json"
+)
+
+var reFSUUID = regexp.MustCompile(`^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$`)
+
+// InternalPlaceRecord is the state file the maker writes once the volume exists and is formatted.
+type InternalPlaceRecord struct {
+	FSUUID string `json:"fs_uuid"`
+	GiB    int    `json:"gib,omitempty"`
+	MadeBy string `json:"made_by,omitempty"` // "installer" | "signed-job"
+	MadeAt string `json:"made_at,omitempty"`
+}
+
+// ReadInternalPlace reads the record; ok=false when there is none (the common case: a box with no internal place).
+func ReadInternalPlace(file string) (InternalPlaceRecord, bool, error) {
+	var rec InternalPlaceRecord
+	b, err := os.ReadFile(file)
+	if errors.Is(err, os.ErrNotExist) {
+		return rec, false, nil
+	}
+	if err != nil {
+		return rec, false, err
+	}
+	if err := json.Unmarshal(b, &rec); err != nil {
+		return rec, false, fmt.Errorf("internal place record %s: %w", file, err)
+	}
+	if !reFSUUID.MatchString(rec.FSUUID) {
+		return rec, false, fmt.Errorf("internal place record %s: fs_uuid %q is not a filesystem UUID", file, rec.FSUUID)
+	}
+	return rec, true, nil
+}
+
+// WriteInternalPlace writes the record atomically (0600).
+func WriteInternalPlace(file string, rec InternalPlaceRecord) error {
+	if !reFSUUID.MatchString(rec.FSUUID) {
+		return fmt.Errorf("internal place: fs_uuid %q is not a filesystem UUID", rec.FSUUID)
+	}
+	b, err := json.MarshalIndent(rec, "", "  ")
+	if err != nil {
+		return err
+	}
+	tmp := file + ".tmp"
+	if err := os.WriteFile(tmp, append(b, '\n'), 0o600); err != nil {
+		return err
+	}
+	return os.Rename(tmp, file)
+}
+
+// internalPlaceState memoises what EnsureInternalPlace last saw, so the 20-second tick logs a state CHANGE once and
+// does no work on the steady state.
+type internalPlaceState struct {
+	mu      sync.Mutex
+	done    string // the fs-UUID that is mounted and recorded enrolled
+	lastWhy string // the last reason it could not be ensured (logged once per change)
+}
+
+// internalPlaceUUID returns the configured internal place's fs-UUID, or "" when this box has none (or the record is
+// unreadable — logged by EnsureInternalPlace).
+func (s *Server) internalPlaceUUID() string {
+	if s.internalPlaceFile == "" {
+		return ""
+	}
+	rec, ok, err := ReadInternalPlace(s.internalPlaceFile)
+	if err != nil || !ok {
+		return ""
+	}
+	return rec.FSUUID
+}
+
+// isInternalPlace reports whether a host path is this box's internal place: its raw mount (/mnt/belso) or its bind
+// under the guests' shared parent (/mnt/felhom-drives/belso — the path POST /disks/same-disk judges).
+func (s *Server) isInternalPlace(hostPath string) bool {
+	p := path.Clean(hostPath)
+	return (p == InternalPlaceWhere || p == StableParentDir+"/"+InternalPlaceName) && s.internalPlaceUUID() != ""
+}
+
+// EnsureInternalPlace mounts the internal place on the host at /mnt/belso by fs-UUID and records it `enrolled`,
+// when this box has one. Idempotent and cheap on the steady state; safe on the 20-second tick. It never formats,
+// never unmounts, and never mounts anything at /mnt/belso that is not the recorded UUID: a household drive that
+// happens to be named „belso" keeps its mount, and the internal place waits (logged once).
+func (s *Server) EnsureInternalPlace(ctx context.Context) {
+	if s.internalPlaceFile == "" {
+		return
+	}
+	rec, ok, err := ReadInternalPlace(s.internalPlaceFile)
+	if err != nil {
+		s.internalPlaceNote("record unreadable: " + err.Error())
+		return
+	}
+	if !ok {
+		return
+	}
+	uuid := rec.FSUUID
+	st := &s.ipState
+	st.mu.Lock()
+	done := st.done == uuid
+	st.mu.Unlock()
+
+	// What is at /mnt/belso now, if anything?
+	mountedUUID, mounted := "", false
+	if mounts, merr := s.hostReader().Mounts(); merr == nil {
+		for _, m := range mounts {
+			if path.Clean(m.MountPoint) == InternalPlaceWhere {
+				mounted = true
+				if u, okU := s.hostReader().ResolveUUID(m.Device); okU {
+					mountedUUID = u
+				}
+			}
+		}
+	}
+	if mounted && mountedUUID != "" && mountedUUID != uuid {
+		s.internalPlaceNote("another filesystem (uuid " + mountedUUID + ") is mounted at " + InternalPlaceWhere + " — the internal place waits")
+		return
+	}
+	// A Felhom unit for /mnt/belso that names another UUID (a household drive called „belso", unplugged): never
+	// overwrite it — that would silently take the drive's name and mount point.
+	if s.driveTargets != nil {
+		if drives, derr := s.driveTargets.Known(ctx); derr == nil {
+			for _, d := range drives {
+				if path.Clean(d.MountPath) == InternalPlaceWhere && d.UUID != "" && d.UUID != uuid {
+					s.internalPlaceNote("a drive unit for " + InternalPlaceWhere + " names another uuid (" + d.UUID + ") — the internal place waits")
+					return
+				}
+			}
+		}
+	}
+	if mounted && mountedUUID == uuid {
+		if !done {
+			s.recordIntent(ctx, InternalPlaceWhere, "enrolled")
+			st.mu.Lock()
+			st.done, st.lastWhy = uuid, ""
+			st.mu.Unlock()
+			s.logger.Info("internal place: mounted and enrolled", "where", InternalPlaceWhere, "fs_uuid", uuid, "gib", rec.GiB)
+		}
+		return
+	}
+	if s.disks == nil {
+		s.internalPlaceNote("disk management is not configured on this host")
+		return
+	}
+	if s.resolveStorageDevice != nil {
+		if _, rerr := s.resolveStorageDevice("uuid:" + uuid); rerr != nil {
+			s.internalPlaceNote("its volume is not present (uuid " + uuid + ")")
+			return
+		}
+	}
+	start := time.Now()
+	if err := s.disks.EnsureMount(ctx, storage.MountSpec{Name: InternalPlaceName, UUID: uuid, Where: InternalPlaceWhere, FSType: "ext4"}); err != nil {
+		s.internalPlaceNote("mount failed: " + err.Error())
+		return
+	}
+	s.recordIntent(ctx, InternalPlaceWhere, "enrolled")
+	st.mu.Lock()
+	st.done, st.lastWhy = uuid, ""
+	st.mu.Unlock()
+	s.logger.Info("internal place: mounted on the host", "where", InternalPlaceWhere, "fs_uuid", uuid, "gib", rec.GiB,
+		"duration_ms", time.Since(start).Milliseconds())
+}
+
+func (s *Server) internalPlaceNote(why string) {
+	st := &s.ipState
+	st.mu.Lock()
+	changed := st.lastWhy != why
+	st.lastWhy, st.done = why, ""
+	st.mu.Unlock()
+	if changed {
+		s.logger.Warn("internal place: not ensured", "why", why)
+	} else {
+		s.logger.Debug("internal place: still not ensured", "why", why)
+	}
+}
+
+// InternalPlaceFileIn is the record's path inside a state dir.
+func InternalPlaceFileIn(stateDir string) string { return filepath.Join(stateDir, InternalPlaceFile) }

internal/localapi/internalplace_test.go

@@ -0,0 +1,249 @@
+package localapi
+
+import (
+	"context"
+	"errors"
+	"io"
+	"log/slog"
+	"net/http"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
+)
+
+// The internal data place (felhom.eu architecture/16 §5, agent v0.158.0): mounted like an enrolled drive, but never
+// at the cost of a household drive, never formatted, ejected or decommissioned, and the same disk as sys_drive.
+
+const ipUUID = "0b6e4c5a-1d2e-4f3a-9b8c-7d6e5f4a3b2c"
+const ipDev = "/dev/mapper/pve-felhom--belso"
+
+// ipHost is a HostReader whose mount table the test changes, and whose by-uuid map it controls.
+type ipHost struct {
+	mu     sync.Mutex
+	mounts []storage.Mount
+	uuids  map[string]string // device → fs-UUID
+}
+
+func (h *ipHost) Mounts() ([]storage.Mount, error) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return append([]storage.Mount(nil), h.mounts...), nil
+}
+func (h *ipHost) ResolveUUID(dev string) (string, bool) { u, ok := h.uuids[dev]; return u, ok }
+func (h *ipHost) DeviceExists(string) bool              { return true }
+func (h *ipHost) Rotational(string) (bool, bool)        { return false, false }
+func (h *ipHost) Removable(string) (bool, bool)         { return false, false }
+func (h *ipHost) BlockSlaves(string) ([]string, bool)   { return nil, false }
+
+func newIPHost(extra ...storage.Mount) *ipHost {
+	return &ipHost{
+		// root on a whole-disk partition (as sysOnSDA): the system disk resolves, so a USB drive is user-data.
+		mounts: append([]storage.Mount{{Device: "/dev/sda1", MountPoint: "/", FSType: "ext4"}}, extra...),
+		uuids:  map[string]string{ipDev: ipUUID, "/dev/sdb1": "99999999-aaaa-bbbb-cccc-dddddddddddd"},
+	}
+}
+
+type ipRig struct {
+	srv    *Server
+	disks  *fakeDiskOps
+	intent *fakeIntent
+}
+
+func newIPRig(t *testing.T, host *ipHost, known []storage.KnownTarget, record bool) ipRig {
+	t.Helper()
+	dir := t.TempDir()
+	file := filepath.Join(dir, InternalPlaceFile)
+	if record {
+		if err := WriteInternalPlace(file, InternalPlaceRecord{FSUUID: ipUUID, GiB: 183, MadeBy: "installer"}); err != nil {
+			t.Fatal(err)
+		}
+	}
+	d, in := &fakeDiskOps{}, newFakeIntent()
+	srv, err := NewServer(Options{
+		ListenAddr: "127.0.0.1:0", Guests: &fakeGuests{}, Backups: &fakeBackups{}, Store: &fakeStore{},
+		Storage: fakeStorage{}, Tokens: staticTokens{"A": 8200}, Disks: d, DiskGate: &fakeGate{},
+		HostReader: host, Intent: in, DriveTargets: fakeKnownTargets{drives: known},
+		InternalPlaceFile: file, Logger: slog.New(slog.NewTextHandler(io.Discard, nil)),
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv.baseCtx = context.Background()
+	srv.resolveStorageDevice = func(id string) (string, error) {
+		if id == "uuid:"+ipUUID {
+			return "/dev/dm-7", nil
+		}
+		return "", errors.New("absent")
+	}
+	return ipRig{srv, d, in}
+}
+
+func TestInternalPlace_NoRecord_DoesNothing(t *testing.T) {
+	r := newIPRig(t, newIPHost(), nil, false)
+	r.srv.EnsureInternalPlace(context.Background())
+	if len(r.disks.mountCalls) != 0 {
+		t.Fatalf("no record: no mount may be made, got %+v", r.disks.mountCalls)
+	}
+}
+
+func TestInternalPlace_Record_MountsByUUIDAtMntBelso(t *testing.T) {
+	r := newIPRig(t, newIPHost(), nil, true)
+	r.srv.EnsureInternalPlace(context.Background())
+	if len(r.disks.mountCalls) != 1 {
+		t.Fatalf("want exactly one EnsureMount, got %+v", r.disks.mountCalls)
+	}
+	got := r.disks.mountCalls[0]
+	if got.UUID != ipUUID || got.Where != InternalPlaceWhere || got.FSType != "ext4" || got.Name != InternalPlaceName {
+		t.Fatalf("EnsureMount spec: %+v", got)
+	}
+}
+
+func TestInternalPlace_AlreadyMounted_EnrolledOnceNoRemount(t *testing.T) {
+	host := newIPHost(storage.Mount{Device: ipDev, MountPoint: InternalPlaceWhere, FSType: "ext4"})
+	r := newIPRig(t, host, nil, true)
+	r.srv.EnsureInternalPlace(context.Background())
+	r.srv.EnsureInternalPlace(context.Background())
+	if len(r.disks.mountCalls) != 0 {
+		t.Fatalf("already mounted: no EnsureMount, got %+v", r.disks.mountCalls)
+	}
+	if r.intent.Get("uuid:"+ipUUID) != storage.IntentEnrolled {
+		t.Fatalf("the internal place must be recorded enrolled")
+	}
+}
+
+// A household drive called „belso" keeps its mount point: the internal place never takes it.
+// Positive control: TestInternalPlace_Record_MountsByUUIDAtMntBelso (the same record, /mnt/belso free).
+func TestInternalPlace_NeverTakesAHouseholdDriveNamedBelso(t *testing.T) {
+	mounted := newIPHost(storage.Mount{Device: "/dev/sdb1", MountPoint: InternalPlaceWhere, FSType: "ext4"})
+	r := newIPRig(t, mounted, nil, true)
+	r.srv.EnsureInternalPlace(context.Background())
+	if len(r.disks.mountCalls) != 0 || r.intent.Get("uuid:"+ipUUID) != "" {
+		t.Fatalf("a foreign filesystem at /mnt/belso: nothing may be mounted or recorded, got %+v", r.disks.mountCalls)
+	}
+	unplugged := []storage.KnownTarget{{Name: "belso", UUID: "99999999-aaaa-bbbb-cccc-dddddddddddd", MountPath: InternalPlaceWhere, MountBacked: true}}
+	r2 := newIPRig(t, newIPHost(), unplugged, true)
+	r2.srv.EnsureInternalPlace(context.Background())
+	if len(r2.disks.mountCalls) != 0 {
+		t.Fatalf("an unplugged household drive's unit for /mnt/belso must not be overwritten, got %+v", r2.disks.mountCalls)
+	}
+}
+
+func TestInternalPlace_VolumeAbsent_NoMount(t *testing.T) {
+	r := newIPRig(t, newIPHost(), nil, true)
+	r.srv.resolveStorageDevice = func(string) (string, error) { return "", errors.New("absent") }
+	r.srv.EnsureInternalPlace(context.Background())
+	if len(r.disks.mountCalls) != 0 {
+		t.Fatalf("absent volume: no mount, got %+v", r.disks.mountCalls)
+	}
+}
+
+// The household cannot eject or decommission it: its device is a device-mapper volume on the system disk.
+// Positive control: the same calls for a whole-disk USB drive (/dev/sdb1) are not refused by role.
+func TestInternalPlace_EjectAndDecommissionRefused(t *testing.T) {
+	host := newIPHost(
+		storage.Mount{Device: ipDev, MountPoint: InternalPlaceWhere, FSType: "ext4"},
+		storage.Mount{Device: "/dev/sdb1", MountPoint: "/mnt/hdd_1", FSType: "ext4"},
+	)
+	r := newIPRig(t, host, nil, true)
+	h := r.srv.Handler()
+	for _, route := range []string{"/disks/eject", "/disks/decommission"} {
+		if w := do(t, h, "POST", route, "A", `{"where":"/mnt/belso"}`); w.Code != http.StatusForbidden {
+			t.Fatalf("%s /mnt/belso: want 403, got %d %s", route, w.Code, w.Body.String())
+		}
+	}
+	if w := do(t, h, "POST", "/disks/eject", "A", `{"where":"/mnt/hdd_1"}`); w.Code == http.StatusForbidden {
+		t.Fatalf("positive control: a USB drive's eject must not be refused by role, got %d %s", w.Code, w.Body.String())
+	}
+	for _, u := range r.disks.unmountCalls {
+		if u == InternalPlaceWhere {
+			t.Fatalf("the internal place must never be unmounted, got %+v", r.disks.unmountCalls)
+		}
+	}
+}
+
+// The consequence `16` §5 needs: a copy between the internal place and sys_drive is the SAME disk (build A then never
+// counts it), and the place is reported as kind internal.
+type ipIdentHost struct{ fakeIdentHost }
+
+func (h *ipIdentHost) KernelName(dev string) (string, bool) {
+	if dev == ipDev {
+		return "dm-7", true
+	}
+	return h.fakeIdentHost.KernelName(dev)
+}
+func (h *ipIdentHost) Slaves(n string) []string {
+	if n == "dm-7" {
+		return []string{"dm-3"} // felhom-belso → the thin pool
+	}
+	if n == "dm-3" {
+		return []string{"sda3"} // the pool → the system disk's LVM partition
+	}
+	return nil
+}
+
+func TestInternalPlace_IsTheSystemDiskAndKindInternal(t *testing.T) {
+	ih := &ipIdentHost{fakeIdentHost{
+		virt:   "none",
+		parent: map[string]string{"sda3": "sda"},
+		props:  map[string]map[string]string{"sda": {"ID_BUS": "ata", "ID_MODEL": "SanDisk", "ID_SERIAL_SHORT": "1"}},
+		mounts: []storage.Mount{
+			{Device: "/dev/mapper/pve-root", MountPoint: "/", FSType: "ext4"},
+			{Device: "/dev/mapper/pve-root", MountPoint: "/mnt/felhom-drives", FSType: "ext4"},
+			{Device: ipDev, MountPoint: InternalPlaceWhere, FSType: "ext4"},
+			{Device: ipDev, MountPoint: "/mnt/felhom-drives/belso", FSType: "ext4"},
+		},
+	}}
+	fg := &fakeGuestsCfg{mounts: map[int]map[string]string{8200: {
+		"mp0": "local-lvm:vm-8200-disk-1,mp=/var/lib/felhom,backup=1,size=100G",
+		"mp8": "/mnt/felhom-drives,mp=/mnt/felhom-drives",
+	}}}
+	dir := t.TempDir()
+	file := filepath.Join(dir, InternalPlaceFile)
+	if err := WriteInternalPlace(file, InternalPlaceRecord{FSUUID: ipUUID}); err != nil {
+		t.Fatal(err)
+	}
+	srv, err := NewServer(Options{
+		ListenAddr: "127.0.0.1:0", Guests: fg, Backups: &fakeBackups{}, Store: &fakeStore{},
+		Storage: fakeStorage{targets: []hub.StorageTarget{provenSSD}}, Tokens: staticTokens{"A": 8200},
+		HostReader: fakeHostReader{mounts: ih.mounts}, Identity: &storage.IdentityResolver{Host: ih},
+		InternalPlaceFile: file, Logger: slog.New(slog.NewTextHandler(io.Discard, nil)),
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv.baseCtx = context.Background()
+	got, code := sameDisk(t, srv.Handler(), "/mnt/felhom-drives/belso/felhom-data/jellyfin", "/mnt/sys_drive")
+	if code != http.StatusOK || got.Different || !got.Proven || got.Reason != "same_disk" {
+		t.Fatalf("internal place vs sys_drive: want same disk, proven; got %d %+v", code, got)
+	}
+	if got.A.Kind != storage.PlaceKindInternal {
+		t.Fatalf("kind: want %q, got %q", storage.PlaceKindInternal, got.A.Kind)
+	}
+}
+
+func TestInternalPlaceRecord_RefusesANonUUID(t *testing.T) {
+	file := filepath.Join(t.TempDir(), InternalPlaceFile)
+	if err := WriteInternalPlace(file, InternalPlaceRecord{FSUUID: "../../etc"}); err == nil {
+		t.Fatal("a non-UUID must not be written")
+	}
+}
+
+// The root helper's own tests (configs/test_felhom_internal_place.py — the ruled size table, never formatting what
+// holds anything) run with the Go suite.
+func TestInternalPlaceHelperPythonSuite(t *testing.T) {
+	py, err := exec.LookPath("python3")
+	if err != nil {
+		t.Skip("python3 not found")
+	}
+	_, file, _, _ := runtime.Caller(0)
+	script := filepath.Join(filepath.Dir(file), "..", "..", "configs", "test_felhom_internal_place.py")
+	out, err := exec.Command(py, script).CombinedOutput()
+	if err != nil {
+		t.Fatalf("helper suite failed: %v\n%s", err, out)
+	}
+}

internal/localapi/samedisk.go

@@ -0,0 +1,202 @@
+package localapi
+
+import (
+	"context"
+	"net/http"
+	"path"
+	"regexp"
+	"strings"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
+)
+
+// POST /disks/same-disk (v0.157.0) — felhom.eu architecture/16-storage-physical-identity.md §4.
+//
+// The controller asks whether two of ITS paths sit on the same physical disk; the agent answers from its
+// own /sys + udev read, never from the caller's claim (`16` §10). A guest path is mapped only to a place
+// the agent itself made:
+//   - /mnt/felhom-drives/<name>[/…] → the host mount at exactly /mnt/felhom-drives/<name> (the drive's
+//     felhom-data bind, or a network share's mount). A path whose <name> is not mounted there (an absent
+//     drive: the bare directory on the root disk) is UNMAPPED — never "the system disk".
+//   - /mnt/sys_drive, /var/lib/felhom, /var/lib/docker [/…] → the guest's data volume (mp0, mp=/var/lib/felhom;
+//     or a legacy mp at that exact path) → the PVE storage holding it → that storage's identity.
+//   - anything else → unmapped.
+// Answer: {different, proven, reason, a, b}. Act on `proven` first: different+proven = a counted second
+// copy; same_disk+proven = not a second copy; proven=false = unknown (reason vm|network|usb_bridge|
+// weak_wwn|no_serial|unmapped). Pinned by samedisk_test.go.
+
+type sameDiskRequest struct {
+	VMID int    `json:"vmid,omitempty"`
+	A    string `json:"a"`
+	B    string `json:"b"`
+}
+
+// SamePlace is one side of the answer.
+type SamePlace struct {
+	Path          string   `json:"path"`
+	Mapped        bool     `json:"mapped"`
+	Kind          string   `json:"kind,omitempty"`
+	PhysicalDisks []string `json:"physical_disks,omitempty"`
+	Identity      string   `json:"identity,omitempty"`
+	Reason        string   `json:"reason,omitempty"`
+}
+
+// SameDiskResponse is the wire answer.
+type SameDiskResponse struct {
+	Different bool      `json:"different"`
+	Proven    bool      `json:"proven"`
+	Reason    string    `json:"reason,omitempty"`
+	A         SamePlace `json:"a"`
+	B         SamePlace `json:"b"`
+}
+
+// sysDataPaths are the guest paths that live on the guest's one data volume (golden v3: mp0 at
+// /var/lib/felhom, its docker/ and sys_drive/ folders bound in the guest — 07 §7.5.1).
+var sysDataPaths = []string{"/var/lib/felhom", "/mnt/sys_drive", "/var/lib/docker"}
+
+func (s *Server) handleSameDisk(w http.ResponseWriter, r *http.Request, vmid int) {
+	if s.ident == nil {
+		writeErr(w, http.StatusServiceUnavailable, "disk identity not configured on this host")
+		return
+	}
+	var req sameDiskRequest
+	if !decodeBody(w, r, &req) {
+		return
+	}
+	if !s.scopedFromBody(w, req.VMID, vmid, r.URL.Path) {
+		return
+	}
+	if !path.IsAbs(req.A) || !path.IsAbs(req.B) {
+		writeErr(w, http.StatusBadRequest, "a and b must be absolute guest paths")
+		return
+	}
+	a := s.mapGuestPlace(r.Context(), vmid, req.A)
+	b := s.mapGuestPlace(r.Context(), vmid, req.B)
+	resp := SameDiskResponse{A: a.view, B: b.view}
+	resp.Different, resp.Proven, resp.Reason = storage.Relation(a.id, b.id)
+	s.logger.Info("local-api: same-disk", "vmid", vmid, "a", req.A, "b", req.B,
+		"different", resp.Different, "proven", resp.Proven, "reason", resp.Reason)
+	writeOK(w, resp)
+}
+
+type mappedPlace struct {
+	view SamePlace
+	id   storage.PlaceIdentity
+}
+
+func (s *Server) mapGuestPlace(ctx context.Context, vmid int, guestPath string) mappedPlace {
+	p := path.Clean(guestPath)
+	out := mappedPlace{view: SamePlace{Path: p}}
+	set := func(kind string, id storage.PlaceIdentity) mappedPlace {
+		if !id.Computed() {
+			return out
+		}
+		out.id = id
+		out.view.Mapped, out.view.Kind = true, kind
+		out.view.PhysicalDisks, out.view.Identity, out.view.Reason = id.PhysicalDisks, id.Identity, id.Reason
+		return out
+	}
+	if strings.HasPrefix(p, StableParentDir+"/") {
+		name := strings.SplitN(strings.TrimPrefix(p, StableParentDir+"/"), "/", 2)[0]
+		if id, kind, ok := s.ownMountIdentity(StableParentDir + "/" + name); ok {
+			return set(kind, id)
+		}
+		return out
+	}
+	for _, root := range sysDataPaths {
+		if p != root && !strings.HasPrefix(p, root+"/") {
+			continue
+		}
+		id := s.guestDataVolumeIdentity(ctx, vmid, root)
+		return set(storage.PlaceKindSystem, id)
+	}
+	return out
+}
+
+// ownMountIdentity judges a HOST path only when it is ITSELF a mountpoint (an enrolled drive's raw mount
+// or its felhom-data bind, a network share). A path that is not its own mount — an absent drive, whose
+// directory now sits on the root disk — is not computed, never root's identity (the R-118 trap).
+func (s *Server) ownMountIdentity(hostPath string) (storage.PlaceIdentity, string, bool) {
+	if s.ident == nil || hostPath == "" {
+		return storage.PlaceIdentity{}, "", false
+	}
+	mounts, err := s.hostReader().Mounts()
+	if err != nil {
+		return storage.PlaceIdentity{}, "", false
+	}
+	m, ok := storage.MountFor(mounts, hostPath)
+	if !ok || path.Clean(m.MountPoint) != path.Clean(hostPath) {
+		return storage.PlaceIdentity{}, "", false
+	}
+	id := s.ident.HostPath(hostPath)
+	if !id.Computed() {
+		return id, "", false
+	}
+	kind := storage.PlaceKindDisk
+	switch {
+	case s.isInternalPlace(hostPath): // v0.158.0 `16` §5: the one-disk box's data place, on the system disk
+		kind = storage.PlaceKindInternal
+	case id.Reason == storage.ReasonNetwork:
+		kind = storage.PlaceKindNetwork
+	case strings.HasPrefix(m.Device, "/dev/") && !strings.HasPrefix(m.Device, "/dev/mapper/") && isPartitionPath(m.Device):
+		kind = storage.PlaceKindPartition
+	}
+	return id, kind, true
+}
+
+var rePartitionName = regexp.MustCompile(`^(nvme[0-9]+n[0-9]+p[0-9]+|(sd|vd|hd)[a-z]+[0-9]+)$`)
+
+func isPartitionPath(dev string) bool { return rePartitionName.MatchString(path.Base(dev)) }
+
+// guestDataVolumeIdentity finds the guest mountpoint that holds root (mp=/var/lib/felhom on golden v3, or a
+// legacy mp at that exact path) and returns the identity of the PVE storage that holds its volume.
+func (s *Server) guestDataVolumeIdentity(ctx context.Context, vmid int, root string) storage.PlaceIdentity {
+	if s.guests == nil || s.storage == nil {
+		return storage.PlaceIdentity{}
+	}
+	cfg, err := s.guests.GuestConfig(ctx, vmid)
+	if err != nil {
+		return storage.PlaceIdentity{}
+	}
+	storeID, fallback := "", ""
+	for _, spec := range cfg.MountPoints() {
+		st, mp, _ := parseMount(spec)
+		if strings.HasPrefix(st, "/") {
+			continue // a host bind (mp8, mp9), not a volume
+		}
+		switch mp {
+		case root:
+			storeID = st // a legacy mp at exactly this path wins
+		case "/var/lib/felhom":
+			fallback = st // golden v3: the one data volume
+		}
+	}
+	if storeID == "" {
+		storeID = fallback
+	}
+	if storeID == "" {
+		return storage.PlaceIdentity{}
+	}
+	targets, err := s.storage.Observe(ctx)
+	if err != nil {
+		return storage.PlaceIdentity{}
+	}
+	for _, t := range targets {
+		if t.Name == storeID {
+			return identityOfTarget(t)
+		}
+	}
+	return storage.PlaceIdentity{}
+}
+
+func identityOfTarget(t hub.StorageTarget) storage.PlaceIdentity {
+	if t.Identity == "" {
+		return storage.PlaceIdentity{}
+	}
+	disks := t.PhysicalDisks
+	if disks == nil {
+		disks = []string{}
+	}
+	return storage.PlaceIdentity{PhysicalDisks: disks, Identity: t.Identity, Reason: t.IdentityReason}
+}

internal/localapi/samedisk_test.go

@@ -0,0 +1,146 @@
+package localapi
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"log/slog"
+	"net/http"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
+)
+
+// POST /disks/same-disk (`16` §4) — the controller's Tier-2 question, answered from the agent's own read.
+
+type fakeIdentHost struct {
+	mounts []storage.Mount
+	parent map[string]string
+	props  map[string]map[string]string
+	virt   string
+}
+
+func (f *fakeIdentHost) Mounts() ([]storage.Mount, error) { return f.mounts, nil }
+func (f *fakeIdentHost) KernelName(dev string) (string, bool) {
+	if len(dev) > 5 && dev[:5] == "/dev/" {
+		return dev[5:], true
+	}
+	return "", false
+}
+func (f *fakeIdentHost) Parent(n string) (string, bool)        { p, ok := f.parent[n]; return p, ok }
+func (f *fakeIdentHost) Slaves(string) []string                { return nil }
+func (f *fakeIdentHost) LoopBackingFile(string) (string, bool) { return "", false }
+func (f *fakeIdentHost) UdevProps(n string) map[string]string  { return f.props[n] }
+func (f *fakeIdentHost) Virt() string                          { return f.virt }
+
+// sameDiskRig: guest 8200 (token A) with mp0 on local-lvm (the system SSD, proven) + the given mounts.
+func sameDiskRig(t *testing.T, host *fakeIdentHost, localLVM hub.StorageTarget) http.Handler {
+	t.Helper()
+	fg := &fakeGuestsCfg{mounts: map[int]map[string]string{8200: {
+		"mp0": "local-lvm:vm-8200-disk-1,mp=/var/lib/felhom,backup=1,size=70G",
+		"mp8": "/mnt/felhom-drives,mp=/mnt/felhom-drives",
+	}}}
+	srv, err := NewServer(Options{
+		ListenAddr: "127.0.0.1:0", Guests: fg, Backups: &fakeBackups{}, Store: &fakeStore{},
+		Storage: fakeStorage{targets: []hub.StorageTarget{localLVM}}, Tokens: staticTokens{"A": 8200},
+		HostReader: fakeHostReader{mounts: host.mounts},
+		Identity:   &storage.IdentityResolver{Host: host},
+		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv.baseCtx = context.Background()
+	return srv.Handler()
+}
+
+var provenSSD = hub.StorageTarget{Name: "local-lvm", Type: hub.StorageTypeLVMThin, Kind: "system",
+	PhysicalDisks: []string{"serial:ata:SanDisk:1"}, Identity: "proven"}
+
+func baseHost() *fakeIdentHost {
+	return &fakeIdentHost{
+		virt:   "none",
+		parent: map[string]string{"sdc1": "sdc", "sdc2": "sdc"},
+		props: map[string]map[string]string{
+			"sdb": {"ID_BUS": "ata", "ID_MODEL": "TOSHIBA", "ID_SERIAL_SHORT": "65NOP3HDT"},
+			"sdc": {"ID_BUS": "usb", "ID_MODEL": "Portable", "ID_SERIAL_SHORT": "NAAB7C21"},
+		},
+		mounts: []storage.Mount{
+			{Device: "/dev/mapper/pve-root", MountPoint: "/", FSType: "ext4"},
+			{Device: "/dev/mapper/pve-root", MountPoint: "/mnt/felhom-drives", FSType: "ext4"},
+			{Device: "/dev/sdb", MountPoint: "/mnt/felhom-drives/hdd_1", FSType: "ext4"},
+			{Device: "/dev/sdc1", MountPoint: "/mnt/felhom-drives/a", FSType: "ext4"},
+			{Device: "/dev/sdc2", MountPoint: "/mnt/felhom-drives/b", FSType: "ext4"},
+			{Device: "//nas/films", MountPoint: "/mnt/felhom-drives/nas", FSType: "cifs"},
+		},
+	}
+}
+
+func sameDisk(t *testing.T, h http.Handler, a, b string) (SameDiskResponse, int) {
+	t.Helper()
+	body, _ := json.Marshal(map[string]string{"a": a, "b": b})
+	w := do(t, h, "POST", "/disks/same-disk", "A", string(body))
+	var env struct {
+		Data SameDiskResponse `json:"data"`
+	}
+	_ = json.Unmarshal(w.Body.Bytes(), &env)
+	return env.Data, w.Code
+}
+
+func TestSameDisk_DriveVsSystemData_DifferentProven(t *testing.T) {
+	h := sameDiskRig(t, baseHost(), provenSSD)
+	got, code := sameDisk(t, h, "/mnt/felhom-drives/hdd_1/felhom-data/paperless", "/mnt/sys_drive")
+	if code != http.StatusOK || !got.Different || !got.Proven || got.Reason != "" {
+		t.Fatalf("drive vs sys_drive: want different+proven, got %d %+v", code, got)
+	}
+	if got.B.Kind != "system" || got.A.Kind != "disk" {
+		t.Fatalf("kinds: got a=%q b=%q", got.A.Kind, got.B.Kind)
+	}
+}
+
+func TestSameDisk_TwoPartitionsOfOneDisk_SameProven(t *testing.T) {
+	h := sameDiskRig(t, baseHost(), provenSSD)
+	got, _ := sameDisk(t, h, "/mnt/felhom-drives/a", "/mnt/felhom-drives/b/x")
+	if got.Different || !got.Proven || got.Reason != "same_disk" || got.A.Kind != "partition" {
+		t.Fatalf("two partitions: want same+proven, got %+v", got)
+	}
+}
+
+func TestSameDisk_InsideAVM_NotProven(t *testing.T) {
+	host := baseHost()
+	host.virt = "kvm"
+	h := sameDiskRig(t, host, hub.StorageTarget{Name: "local-lvm", Identity: "unknown", IdentityReason: "vm",
+		PhysicalDisks: []string{"serial:scsi:QEMU_HARDDISK:drive-scsi0"}})
+	got, _ := sameDisk(t, h, "/mnt/felhom-drives/hdd_1", "/mnt/sys_drive")
+	if got.Proven || got.Reason != "vm" {
+		t.Fatalf("inside a VM: want not proven (vm), got %+v", got)
+	}
+}
+
+func TestSameDisk_NetworkAndUnmapped(t *testing.T) {
+	h := sameDiskRig(t, baseHost(), provenSSD)
+	if got, _ := sameDisk(t, h, "/mnt/felhom-drives/nas", "/mnt/sys_drive"); got.Proven || got.Reason != "network" {
+		t.Fatalf("a NAS: want not proven (network), got %+v", got)
+	}
+	// An ABSENT drive: its directory sits on the root disk — must be unmapped, never "the system disk".
+	if got, _ := sameDisk(t, h, "/mnt/felhom-drives/gone", "/mnt/sys_drive"); got.Proven || got.Reason != "unmapped" || got.A.Mapped {
+		t.Fatalf("an absent drive: want unmapped, got %+v", got)
+	}
+	if got, _ := sameDisk(t, h, "/opt/elsewhere", "/mnt/sys_drive"); got.Proven || got.Reason != "unmapped" {
+		t.Fatalf("an unknown guest path: want unmapped, got %+v", got)
+	}
+}
+
+func TestSameDisk_ScopedAndValidated(t *testing.T) {
+	h := sameDiskRig(t, baseHost(), provenSSD)
+	if w := do(t, h, "POST", "/disks/same-disk", "A", `{"vmid":9300,"a":"/mnt/sys_drive","b":"/mnt/sys_drive"}`); w.Code != http.StatusForbidden {
+		t.Fatalf("another guest's vmid: got %d want 403", w.Code)
+	}
+	if w := do(t, h, "POST", "/disks/same-disk", "A", `{"a":"relative","b":"/mnt/sys_drive"}`); w.Code != http.StatusBadRequest {
+		t.Fatalf("a relative path: got %d want 400", w.Code)
+	}
+	if w := do(t, h, "POST", "/disks/same-disk", "", `{"a":"/x","b":"/y"}`); w.Code != http.StatusUnauthorized {
+		t.Fatalf("no token: got %d want 401", w.Code)
+	}
+}

internal/localapi/server.go

@@ -208,6 +208,9 @@ type Options struct {
 	// Intent records drive enroll/eject intent for the self-heal watchdog (slice 10 P3). OPTIONAL —
 	// when nil, no intent is recorded (self-heal runs ungated).
 	Intent IntentRecorder
+	// InternalPlaceFile (v0.158.0, felhom.eu `16` §5) is the path of the internal data place record
+	// (InternalPlaceRecord). OPTIONAL — "" means this host has no internal place and EnsureInternalPlace is a no-op.
+	InternalPlaceFile string
 	// GuestBinds persists which user-data drives (by durable-id) are enrolled into each guest, so the
 	// startup re-assert (ReassertGuestBinds) can restore a bind that a re-provision dropped (F9).
 	// OPTIONAL — when nil, guest binds are not recorded and the startup re-assert is a no-op.
@@ -220,6 +223,10 @@ type Options struct {
 	// ROLE (it backs SystemDisks for the eject role-gate + the /disks role hints). OPTIONAL — when nil
 	// it defaults to the production *storage.ProcHostReader. Injectable so the role-gate is testable.
 	HostReader storage.HostReader
+	// Identity computes physical-disk identity (felhom.eu architecture/16-storage-physical-identity.md §3)
+	// for the /disks rows and POST /disks/same-disk. OPTIONAL — when nil, /disks carries no identity and
+	// same-disk answers 503 "not configured" (the controller then keeps its old st_dev rule).
+	Identity *storage.IdentityResolver
 	// HostMetrics serves GET /host/metrics (slice 9) — host-wide health (cpu%/mem/load/uptime/
 	// cpu-temp) + per-storage capacity, host-wide and token-authed (one-customer-per-host). When
 	// nil the endpoint reports "not configured" (host still reports/reconciles).
@@ -312,11 +319,14 @@ type Server struct {
 	// identity blob from the hub, unseal it with the customer's recovery code, return ONLY the
 	// offsite repository password. OPTIONAL — nil (no hub client configured) makes
 	// POST /escrow/recover-offsite-password answer 503 rather than pretending.
-	escrowRecovery EscrowRecoverer
-	intent         IntentRecorder      // slice 10 P3 (optional)
-	guestBinds     *GuestBindStore     // F9 startup bind re-assert record (optional)
-	formatJobs     *FormatJobStore     // F20-BUG3 detached-format job record (optional)
-	staleLock      StaleLockController // F2-b startup stale-lock recovery (optional)
+	escrowRecovery    EscrowRecoverer
+	intent            IntentRecorder                      // slice 10 P3 (optional)
+	internalPlaceFile string                              // v0.158.0 `16` §5 (optional)
+	ipState           internalPlaceState                  // EnsureInternalPlace's memo
+	guestBinds        *GuestBindStore                     // F9 startup bind re-assert record (optional)
+	formatJobs        *FormatJobStore                     // F20-BUG3 detached-format job record (optional)
+	staleLock         StaleLockController                 // F2-b startup stale-lock recovery (optional)
+	partialSweep      func(ctx context.Context, vmid int) // R-1006 start-up sweep of dead vzdump leftovers (optional)
 	// guestPower (F-REBOOT) is per-guest start-attempt state for the guest-power watchdog.
 	// Guarded by guestPowerMu in guestpower.go; in-memory on purpose (see guestPowerState).
 	guestPower map[int]guestPowerState
@@ -324,7 +334,8 @@ type Server struct {
 	// guestPowerSweeps counts completed guest-power sweeps, for the liveness observable. Touched only
 	// from GuestPowerTick, which the ticker calls serially.
 	guestPowerSweeps int
-	host             storage.HostReader // role classification source (optional; defaults to ProcHostReader)
+	host             storage.HostReader        // role classification source (optional; defaults to ProcHostReader)
+	ident            *storage.IdentityResolver // `16` §3 physical-disk identity (optional)
 
 	hostMetrics  HostMetricsProvider // slice 9 (optional)
 	hostID       string              // slice 10B: for the data-bearing-format pending-op hint
@@ -394,6 +405,10 @@ type Server struct {
 	// detached pipeline runs through (tests inject; production defaults set in NewServer).
 	netVerifyMu  sync.Mutex
 	netVerifyCur *netVerifyJob
+
+	// R-998: POST /host/poweroff (nil = not configured → 503); one guard-and-mark decision at a time.
+	powerOff   *HostPowerOffConfig
+	powerOffMu sync.Mutex
 	// netTrigger performs the mount-waking directory read through the automount path (Q1).
 	netTrigger func(where string) error
 	// netMounted judges mount success from /proc/mounts — the §8 truth source (never readability).
@@ -445,42 +460,44 @@ func NewServer(o Options) (*Server, error) {
 		cadence = defaultBackupCadence
 	}
 	s := &Server{
-		addr:            o.ListenAddr,
-		cert:            o.Cert,
-		guests:          o.Guests,
-		backups:         o.Backups,
-		store:           o.Store,
-		storage:         o.Storage,
-		driveTargets:    o.DriveTargets,
-		smart:           o.Smart,
-		tokens:          o.Tokens,
-		cadence:         cadence,
-		logger:          o.Logger,
-		now:             func() time.Time { return time.Now().UTC() },
-		disks:           o.Disks,
-		diskGate:        o.DiskGate,
-		guestList:       o.Guests2,
-		guestAttach:     o.GuestAttach,
-		mem:             o.Memory,
-		netStorage:      o.NetStorage,
-		privileged:      o.Privileged,
-		configPath:      o.ConfigPath,
-		stateDir:        o.StateDir,
-		netMountRoot:    storage.NetworkMountRoot,
-		smbCredsDir:     o.SmbCredsDir,
-		escrowStagePath: o.EscrowStagePath,
-		escrowRecovery:  o.EscrowRecovery,
-		intent:          o.Intent,
-		guestBinds:      o.GuestBinds,
-		formatJobs:      o.FormatJobs,
-		staleLock:       o.StaleLock,
-		host:            o.HostReader,
-		hostMetrics:     o.HostMetrics,
-		hostID:          o.HostID,
-		agentVersion:    o.AgentVersion,
-		logRing:         o.LogRing,
-		jobs:            map[backupJobKey]*backupJob{},
-		swapInFlight:    map[int]bool{},
+		addr:              o.ListenAddr,
+		cert:              o.Cert,
+		guests:            o.Guests,
+		backups:           o.Backups,
+		store:             o.Store,
+		storage:           o.Storage,
+		driveTargets:      o.DriveTargets,
+		smart:             o.Smart,
+		tokens:            o.Tokens,
+		cadence:           cadence,
+		logger:            o.Logger,
+		now:               func() time.Time { return time.Now().UTC() },
+		disks:             o.Disks,
+		diskGate:          o.DiskGate,
+		guestList:         o.Guests2,
+		guestAttach:       o.GuestAttach,
+		mem:               o.Memory,
+		netStorage:        o.NetStorage,
+		privileged:        o.Privileged,
+		configPath:        o.ConfigPath,
+		stateDir:          o.StateDir,
+		netMountRoot:      storage.NetworkMountRoot,
+		smbCredsDir:       o.SmbCredsDir,
+		escrowStagePath:   o.EscrowStagePath,
+		escrowRecovery:    o.EscrowRecovery,
+		intent:            o.Intent,
+		internalPlaceFile: o.InternalPlaceFile,
+		guestBinds:        o.GuestBinds,
+		formatJobs:        o.FormatJobs,
+		staleLock:         o.StaleLock,
+		host:              o.HostReader,
+		ident:             o.Identity,
+		hostMetrics:       o.HostMetrics,
+		hostID:            o.HostID,
+		agentVersion:      o.AgentVersion,
+		logRing:           o.LogRing,
+		jobs:              map[backupJobKey]*backupJob{},
+		swapInFlight:      map[int]bool{},
 	}
 	// R-82 tier resolution. Options.BackupTiers is authoritative when supplied; otherwise ONE tier
 	// is synthesized from Backups + BackupCadence — the pre-R-82 shape, so every existing caller
@@ -541,6 +558,7 @@ func (s *Server) Handler() http.Handler {
 	// Disk management (slice 8C) — self-scoped; format routes through the data-bearing classifier+gate.
 	mux.HandleFunc("GET /disks", s.withGuest(s.handleDisks))
 	mux.HandleFunc("GET /disks/candidates", s.withGuest(s.handleDiskCandidates))
+	mux.HandleFunc("POST /disks/same-disk", s.withGuest(s.handleSameDisk)) // `16` §4 (v0.157.0)
 	mux.HandleFunc("POST /disks/assign", s.withGuest(s.handleDiskAssign))
 	mux.HandleFunc("POST /disks/eject", s.withGuest(s.handleDiskEject))
 	mux.HandleFunc("POST /disks/decommission", s.withGuest(s.handleDiskDecommission))
@@ -550,6 +568,8 @@ func (s *Server) Handler() http.Handler {
 	mux.HandleFunc("POST /disks/guest-attach", s.withGuest(s.handleDiskGuestAttach))
 	// Guest reboot (slice 10 P2 activation): user-triggered restart to activate pending drive binds.
 	mux.HandleFunc("POST /guest/reboot", s.withGuest(s.handleGuestReboot))
+	// Host power-off (R-998, doc 14): the household's „A gép kikapcsolása". Guarded in hostpoweroff.go.
+	mux.HandleFunc("POST /host/poweroff", s.withGuest(s.handleHostPowerOff))
 	// Guest RAM resize (v0.90.0, R-24): read current allocation + bounds, and apply a bounded resize
 	// (live cgroup apply, no reboot). Self-scoped; the agent enforces every bound fresh per request.
 	mux.HandleFunc("GET /guest/memory", s.withGuest(s.handleGuestMemory))
@@ -825,6 +845,10 @@ func (s *Server) handleBackup(w http.ResponseWriter, r *http.Request, vmid int)
 		return
 	}
 	key := backupJobKey{vmid: vmid, target: tier.TargetID}
+	// R-899 (operator ruling 2026-10-08): a household press („Mentés most") is not the night's backup. A controller
+	// that knows sends `trigger=manual`; then the OS leg does not follow (it belongs to the night, after the night's
+	// own copy). An older controller sends nothing and keeps the old behaviour.
+	manual := r.URL.Query().Get("trigger") == "manual"
 
 	// ONE BACKUP AT A TIME PER GUEST, ACROSS ALL TIERS (operator ruling 2026-07-26: "other backup
 	// shouldn't start until finished"). vzdump takes a guest lock, so a concurrent second backup
@@ -926,7 +950,9 @@ func (s *Server) handleBackup(w http.ResponseWriter, r *http.Request, vmid int)
 		}
 		s.finishJob(key, jobID, b)
 		// OS leg (agent v0.140.0): after the night's whole-guest copy exists, still holding the heavy-op gate.
-		if b.Success && tier.Primary && s.afterPrimaryBackup != nil {
+		if b.Success && tier.Primary && s.afterPrimaryBackup != nil && manual {
+			s.logger.Info("local-api: no OS leg after a manual backup — it follows the night's own backup (R-899)", "vmid", vmid, "job", jobID)
+		} else if b.Success && tier.Primary && s.afterPrimaryBackup != nil {
 			s.afterPrimaryBackup(base, vmid)
 		}
 	}()

internal/localapi/stalelock.go

@@ -4,7 +4,11 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"os"
+	"path/filepath"
 	"strconv"
+	"strings"
+	"sync"
 
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
 )
@@ -142,6 +146,10 @@ type staleLockController struct {
 	runner proxmox.Runner
 	pool   string       // ownership registry: only members of this PVE pool are ever scanned (A1)
 	logger *slog.Logger // the one success-path scan-summary line; nil = silent
+	// procDir is where taskAlive reads /proc/<pid>/stat (R-1008); "" = /proc. Tests point it at a fixture.
+	procDir  string
+	deadMu   sync.Mutex
+	deadSeen map[string]bool // UPIDs of dead tasks already logged (once per task)
 }
 
 // staleLockAPI is the subset of *proxmox.Client the controller uses (kept narrow for clarity/testing).
@@ -209,19 +217,100 @@ func (c *staleLockController) Lock(ctx context.Context, vmid int) (string, bool,
 	return cfg.Lock(), cfg.OnBoot(), nil
 }
 
+// BackupRunning is THE answer to „is a vzdump in flight for vmid" for all four callers (startup stale-lock
+// recovery, the guest-power watchdog, the household power-off guard, the controller supervisor): every one of
+// them reaches this method through the StaleLockController interface. R-1008: Proxmox keeps a task in
+// `tasks?source=active` after a power cut — nobody is left to end it (measured on demo-hp 2026-10-14: still
+// listed RUNNING ~30–60 s after the boot) — so a listed task whose worker process is gone is dead, not in flight.
 func (c *staleLockController) BackupRunning(ctx context.Context, vmid int) (bool, error) {
 	tasks, err := c.px.ListRunningTasks(ctx)
 	if err != nil {
 		return false, err
 	}
+	proc := c.procDir
+	if proc == "" {
+		proc = "/proc"
+	}
+	running, dead := vzdumpInFlight(tasks, vmid, proc)
+	for _, t := range dead {
+		c.logDeadOnce(t, vmid)
+	}
+	return running, nil
+}
+
+// vzdumpInFlight decides, from the node's active-task list, whether a vzdump for vmid is in flight: a matching
+// task is in flight while its worker process lives (taskAlive). A task whose worker is gone is dead (returned in dead,
+// for the log). FAIL SAFE on doubt — the old answer: a UPID that does not parse, or a /proc entry that cannot be read,
+// counts as in flight. Pure over procDir; pinned by stalelock_inflight_test.go.
+func vzdumpInFlight(tasks []proxmox.TaskStatus, vmid int, procDir string) (bool, []proxmox.TaskStatus) {
 	id := strconv.Itoa(vmid)
+	var dead []proxmox.TaskStatus
 	for _, t := range tasks {
 		// A single-guest vzdump task carries the vmid in its ID field.
-		if t.Type == "vzdump" && t.ID == id {
+		if t.Type != "vzdump" || t.ID != id {
+			continue
+		}
+		alive, known := taskAlive(procDir, t.UPID)
+		if !known || alive {
 			return true, nil
 		}
+		dead = append(dead, t)
 	}
-	return false, nil
+	return false, dead
+}
+
+// taskAlive is Proxmox's own liveness rule for a task (PVE::ProcFSTools::check_process_running): the UPID names the
+// worker's pid and its start time in clock ticks since boot (pstart); the task lives while /proc/<pid>/stat exists with
+// that same start time (field 22). No wall clock is involved — a clock step after the boot (an NTP correction after a
+// power cut) cannot make a live task look dead (the 2026-10-14 security review of the first, btime-based version).
+// known=false: the UPID does not parse, or /proc/<pid>/stat exists but cannot be read or parsed.
+func taskAlive(procDir, upid string) (alive, known bool) {
+	u, err := proxmox.ParseUPID(upid)
+	if err != nil || u.PID == 0 {
+		return false, false
+	}
+	raw, err := os.ReadFile(filepath.Join(procDir, strconv.FormatUint(u.PID, 10), "stat"))
+	if err != nil {
+		if os.IsNotExist(err) {
+			// „no such process" is only an answer if this agent can see other users' processes at all (a /proc mounted
+			// hidepid=, or a unit with ProtectProc=, hides root's workers — every task would then look dead). PID 1 is
+			// root's; not seeing it means not knowing.
+			if _, err1 := os.Stat(filepath.Join(procDir, "1", "stat")); err1 != nil {
+				return false, false
+			}
+			return false, true // no such process in this boot: the worker is gone
+		}
+		return false, false
+	}
+	st := string(raw)
+	i := strings.LastIndexByte(st, ')') // the comm field may hold spaces and parentheses
+	if i < 0 {
+		return false, false
+	}
+	f := strings.Fields(st[i+1:]) // f[0] is field 3 (state), so field 22 (starttime) is f[19]
+	if len(f) < 20 {
+		return false, false
+	}
+	start, err := strconv.ParseUint(f[19], 10, 64)
+	if err != nil {
+		return false, false
+	}
+	// Proxmox's rule exactly: the start tick matches (a pstart of 0 is not checked) and the process is not a zombie.
+	return (u.PStart == 0 || start == u.PStart) && f[0] != "Z", true
+}
+
+func (c *staleLockController) logDeadOnce(t proxmox.TaskStatus, vmid int) {
+	c.deadMu.Lock()
+	defer c.deadMu.Unlock()
+	if c.deadSeen == nil {
+		c.deadSeen = map[string]bool{}
+	}
+	if c.deadSeen[t.UPID] || c.logger == nil {
+		return
+	}
+	c.deadSeen[t.UPID] = true
+	c.logger.Warn("backup-in-flight: a vzdump task is listed as active but its worker process is gone — it is dead, not running",
+		"vmid", vmid, "upid", t.UPID)
 }
 
 func (c *staleLockController) HasVzdumpSnapshot(ctx context.Context, vmid int) (bool, error) {

internal/localapi/stalelock_inflight_test.go

@@ -0,0 +1,266 @@
+package localapi
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// R-1008: after a power cut Proxmox keeps the dead vzdump task in `tasks?source=active` (measured on demo-hp
+// 2026-10-14: still RUNNING ~30–60 s after the boot). A task whose worker process is gone is dead, not in flight.
+// Liveness is Proxmox's own rule (pid + pstart vs /proc/<pid>/stat field 22), never the wall clock: the first version
+// compared start time with btime and a clock step after the boot could make a live task look dead (security review
+// 2026-10-14). These tests pin the helper, the production controller, three callers end to end; the fourth (the
+// controller supervisor) by the structural pin at the bottom.
+
+// A worker: pid 0x1E6EEC = 1994476, pstart 0x1B4A0D = 1788429 (UPID hex fields).
+const (
+	testPID    = 1994476
+	testPStart = 1788429
+)
+
+func vz(vmid string) proxmox.TaskStatus {
+	return proxmox.TaskStatus{UPID: "UPID:demo-hp:001E6EEC:001B4A0D:6ACF4071:vzdump:" + vmid + ":felhom-agent@pve!agent:",
+		Type: "vzdump", ID: vmid, Status: "RUNNING", StartTime: 1791967345}
+}
+
+// procFixture writes <dir>/<pid>/stat with the given start ticks (comm with a space and a parenthesis, as real ones can).
+func procFixture(t *testing.T, pid int, start int) string {
+	return procFixtureState(t, pid, start, "S")
+}
+
+func procFixtureState(t *testing.T, pid int, start int, state string) string {
+	t.Helper()
+	d := t.TempDir()
+	// PID 1 is always visible on a real host; procFixtureHidden leaves it out
+	if err := os.MkdirAll(filepath.Join(d, "1"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(d, "1", "stat"), []byte("1 (systemd) S 0 1 1 0 -1 0 0 0 0 0 0 0 0 0 20 0 1 0 2 0 0\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if pid > 0 {
+		p := filepath.Join(d, itoaT(pid))
+		if err := os.MkdirAll(p, 0o755); err != nil {
+			t.Fatal(err)
+		}
+		f := []string{itoaT(pid), "(task UPID:x (vzdump))", state}
+		for i := 4; i <= 21; i++ {
+			f = append(f, "0")
+		}
+		f = append(f, itoaT(start), "0", "0")
+		if err := os.WriteFile(filepath.Join(p, "stat"), []byte(strings.Join(f, " ")+"\n"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return d
+}
+
+// RED-PROOF: make taskAlive return (true, true) for a missing /proc entry → the dead task runs → fails.
+func TestVzdumpInFlight_WorkerGoneIsDead(t *testing.T) {
+	running, dead := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, procFixture(t, 0, 0))
+	if running || len(dead) != 1 {
+		t.Fatalf("a task whose worker is gone must be dead: running=%v dead=%d", running, len(dead))
+	}
+}
+
+// RED-PROOF: drop the `start == u.PStart` comparison (alive whenever the pid exists) → a reused pid runs → fails.
+func TestVzdumpInFlight_ReusedPidIsDead(t *testing.T) {
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, procFixture(t, testPID, 42)); running {
+		t.Fatal("the pid exists but started at another tick: another process, the task is dead")
+	}
+}
+
+// RED-PROOF: drop the `f[0] != "Z"` test → a zombie worker counts as running → fails.
+func TestVzdumpInFlight_ZombieIsDead(t *testing.T) {
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, procFixtureState(t, testPID, testPStart, "Z")); running {
+		t.Fatal("a zombie worker is not running (Proxmox's own rule)")
+	}
+}
+
+func TestVzdumpInFlight_LiveWorkerRuns(t *testing.T) {
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, procFixture(t, testPID, testPStart)); !running {
+		t.Fatal("the worker lives (same pid, same start tick): in flight")
+	}
+}
+
+// The reason for the rewrite: the wall clock plays no part. A live task whose list start time lies „before the boot"
+// (a clock step after the boot) is still running.
+func TestVzdumpInFlight_ClockStepCannotKillALiveTask(t *testing.T) {
+	tk := vz("9201")
+	tk.StartTime = 1 // absurdly early by the wall clock
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{tk}, 9201, procFixture(t, testPID, testPStart)); !running {
+		t.Fatal("a live worker must count as running whatever its wall-clock start says")
+	}
+}
+
+// RED-PROOF: make an unparsable UPID or unreadable stat „known dead" → fails.
+func TestVzdumpInFlight_DoubtFailsSafe(t *testing.T) {
+	bad := vz("9201")
+	bad.UPID = "garbage"
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{bad}, 9201, procFixture(t, 0, 0)); !running {
+		t.Fatal("an unparsable UPID must count as running (fail safe)")
+	}
+	d := procFixture(t, testPID, testPStart)
+	if err := os.WriteFile(filepath.Join(d, itoaT(testPID), "stat"), []byte("garbage"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, d); !running {
+		t.Fatal("an unparsable stat must count as running (fail safe)")
+	}
+}
+
+// RED-PROOF: drop the PID-1 visibility check → a hidden /proc makes the live task „gone" → fails.
+func TestVzdumpInFlight_HiddenProcFailsSafe(t *testing.T) {
+	d := t.TempDir() // nothing visible: not even PID 1 (hidepid / ProtectProc)
+	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201")}, 9201, d); !running {
+		t.Fatal("a /proc that hides other users' processes must count as running (fail safe)")
+	}
+}
+
+func TestVzdumpInFlight_OtherGuestOrTypeIgnored(t *testing.T) {
+	tasks := []proxmox.TaskStatus{vz("9202"), {UPID: vz("9201").UPID, Type: "vzsnapshot", ID: "9201"}}
+	if running, dead := vzdumpInFlight(tasks, 9201, procFixture(t, testPID, testPStart)); running || len(dead) != 0 {
+		t.Fatalf("other guests' and other types' tasks are not 9201's backup: running=%v dead=%d", running, len(dead))
+	}
+}
+
+func inflightCtrl(api *fakeStaleLockAPI, runner *recordingRunner, logger *slog.Logger, proc string) *staleLockController {
+	c := NewStaleLockController(api, runner, "felhom", logger).(*staleLockController)
+	c.procDir = proc
+	return c
+}
+
+// The production controller answers through the helper, and logs a dead task ONCE.
+// RED-PROOF: make BackupRunning ignore the helper (any listed task runs) → fails.
+func TestStaleLockController_BackupRunningIgnoresDeadTask(t *testing.T) {
+	var buf bytes.Buffer
+	api := &fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201")}}
+	c := inflightCtrl(api, &recordingRunner{}, slog.New(slog.NewTextHandler(&buf, nil)), procFixture(t, 0, 0))
+	for i := 0; i < 3; i++ {
+		if running, err := c.BackupRunning(context.Background(), 9201); err != nil || running {
+			t.Fatalf("dead task reported running=%v err=%v", running, err)
+		}
+	}
+	if n := strings.Count(buf.String(), "backup-in-flight: a vzdump task is listed as active but its worker process is gone"); n != 1 {
+		t.Fatalf("the dead task must be logged exactly once, got %d", n)
+	}
+	c.procDir = procFixture(t, testPID, testPStart)
+	if running, _ := c.BackupRunning(context.Background(), 9201); !running {
+		t.Fatal("a live worker must be running")
+	}
+}
+
+func fixtureFor(t *testing.T, alive bool) string {
+	if alive {
+		return procFixture(t, testPID, testPStart)
+	}
+	return procFixture(t, 0, 0)
+}
+
+func poolOf(vmids ...int) proxmox.PoolInfo {
+	var p proxmox.PoolInfo
+	raw := `{"members":[`
+	for i, v := range vmids {
+		if i > 0 {
+			raw += ","
+		}
+		raw += `{"vmid":` + itoaT(v) + `,"type":"lxc"}`
+	}
+	raw += `]}`
+	_ = json.Unmarshal([]byte(raw), &p)
+	return p
+}
+
+// Caller 1 — the startup stale-lock recovery clears the lock a power cut left (the night of 2026-10-14 it said
+// „genuinely in-flight — leaving the lock").
+func TestCaller_StartupStaleLockClearsAfterPowerCut(t *testing.T) {
+	for _, tc := range []struct {
+		alive   bool
+		cleared bool
+	}{{false, true}, {true, false}} {
+		api := &fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201")},
+			cfg: map[int]proxmox.GuestConfig{9201: staleCfg("backup", true)}}
+		runner := &recordingRunner{}
+		s := &Server{staleLock: inflightCtrl(api, runner, nil, fixtureFor(t, tc.alive)), logger: slog.New(slog.NewTextHandler(discardW{}, nil))}
+		s.recoverOneStaleLock(context.Background(), proxmox.Guest{VMID: 9201, Status: "running"})
+		if runner.unlocked("9201") != tc.cleared {
+			t.Fatalf("worker alive=%v: unlocked=%v, want %v", tc.alive, runner.unlocked("9201"), tc.cleared)
+		}
+	}
+}
+
+// Caller 2 — the guest-power watchdog starts a stopped guest despite a dead pre-boot vzdump task.
+func TestCaller_GuestPowerStartsGuestAfterPowerCut(t *testing.T) {
+	for _, tc := range []struct {
+		alive   bool
+		started bool
+	}{{false, true}, {true, false}} {
+		api := &fakeStaleLockAPI{lxc: []proxmox.Guest{{VMID: 9201, Status: "stopped"}}, pool: poolOf(9201),
+			tasks: []proxmox.TaskStatus{vz("9201")}, cfg: map[int]proxmox.GuestConfig{9201: staleCfg("", true)}}
+		s := gpServer(t, inflightCtrl(api, &recordingRunner{}, nil, fixtureFor(t, tc.alive)), nil)
+		s.GuestPowerTick(context.Background())
+		if (len(api.started) == 1) != tc.started {
+			t.Fatalf("worker alive=%v: started=%v, want %v", tc.alive, api.started, tc.started)
+		}
+	}
+}
+
+// Caller 3 — the household power-off guard does not refuse „backup running" for a dead task.
+func TestCaller_PowerOffJobBlockerIgnoresDeadTask(t *testing.T) {
+	for _, tc := range []struct {
+		alive bool
+		want  string
+	}{{false, ""}, {true, PowerOffBackup}} {
+		rig := newPowerRig(t, 0)
+		rig.srv.staleLock = inflightCtrl(&fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201")}}, &recordingRunner{}, nil, fixtureFor(t, tc.alive))
+		if code, _ := rig.srv.jobBlocker(context.Background(), 9201); code != tc.want {
+			t.Fatalf("worker alive=%v: jobBlocker=%q, want %q", tc.alive, code, tc.want)
+		}
+	}
+}
+
+// Caller 4 (the supervisor), the R-1006 cleanup (VzdumpInFlight) and the rest — structural pin: every non-test BackupRunning call in this package goes through
+// s.staleLock (whose one production implementation is staleLockController, which uses vzdumpInFlight), and no
+// other production type implements BackupRunning. If someone adds a second path, this fails.
+func TestBackupRunning_AllCallersUseTheOneHelper(t *testing.T) {
+	files, _ := filepath.Glob("*.go")
+	call := regexp.MustCompile(`([A-Za-z_.]+)\.BackupRunning\(`)
+	impl := regexp.MustCompile(`func \([a-z]+ \*?([A-Za-z]+)\) BackupRunning\(`)
+	callers := 0
+	for _, f := range files {
+		if strings.HasSuffix(f, "_test.go") {
+			continue
+		}
+		b, err := os.ReadFile(f)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, m := range call.FindAllStringSubmatch(string(b), -1) {
+			if m[1] != "s.staleLock" {
+				t.Errorf("%s: BackupRunning called on %q, not s.staleLock", f, m[1])
+			}
+			callers++
+		}
+		for _, m := range impl.FindAllStringSubmatch(string(b), -1) {
+			if m[1] != "staleLockController" {
+				t.Errorf("%s: a second production BackupRunning on %s", f, m[1])
+			}
+		}
+	}
+	if callers != 5 {
+		t.Errorf("expected the five known callers (stale-lock, guest-power, power-off, supervisor, the R-1006 cleanup), found %d", callers)
+	}
+	b, _ := os.ReadFile("stalelock.go")
+	if !strings.Contains(string(b), "vzdumpInFlight(tasks, vmid, proc)") {
+		t.Error("staleLockController.BackupRunning no longer answers through vzdumpInFlight")
+	}
+}

internal/localapi/vzpartial_sweep.go

@@ -0,0 +1,33 @@
+package localapi
+
+import "context"
+
+// R-1006: the half-written vzdump cleanup's two needs from the Server, and its start-up sweep. The cleaner itself is
+// internal/vzpartial; the root helper is configs/felhom-vzdump-partial-clean.
+
+// VzdumpInFlight is the one in-flight answer (staleLockController.BackupRunning, R-1008) for the cleanup. No stale-lock
+// controller wired → true: fail safe, nothing is removed.
+func (s *Server) VzdumpInFlight(ctx context.Context, vmid int) (bool, error) {
+	if s.staleLock == nil {
+		return true, nil
+	}
+	return s.staleLock.BackupRunning(ctx, vmid)
+}
+
+// SetPartialSweep sets the start-up sweep: called with every owned guest (the felhom pool, ownership proven).
+func (s *Server) SetPartialSweep(fn func(ctx context.Context, vmid int)) { s.partialSweep = fn }
+
+// SweepVzdumpPartials runs the sweep once for every owned guest. No-op when unwired.
+func (s *Server) SweepVzdumpPartials(ctx context.Context) {
+	if s.partialSweep == nil || s.staleLock == nil {
+		return
+	}
+	guests, err := s.staleLock.Guests(ctx)
+	if err != nil {
+		s.logger.Warn("vzdump-partial: guest list unavailable — skipping the start-up sweep", "err", err)
+		return
+	}
+	for _, g := range guests {
+		s.partialSweep(ctx, g.VMID)
+	}
+}

internal/osupdate/kernel.go

@@ -0,0 +1,446 @@
+package osupdate
+
+// The kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11). The root half is felhom-os-apply's layer "kernel"
+// (configs/, its own tests); this file decides WHEN and judges the boot:
+//
+//   - the night leg (Run → runKernel): after a healthy host step, on a night the hub marks as told (the household was
+//     mailed the day before — no mail, no step): ring 0 STAGES the pending kernel (select pending-kernel, the root-owned
+//     ring-0 mark) and reboots; ring 1 reboots only a step a signed os_kernel_step staged earlier (KernelStepExecutor).
+//   - after a boot (KernelAfterBoot, at daemon start): the wrapper says what became of the step. On the new kernel the
+//     agent JUDGES the boot — the host health rule (`11` §8.2: the Proxmox daemons, the guest running and healthy, the
+//     tunnel) AND the box reaching the hub — for KernelJudgeWait. Healthy → kernel-good (the new kernel becomes the
+//     default). Not healthy by the deadline → ONE self-revert (kernel-revert: a reboot into the old kernel, still the
+//     default). A crash on the new kernel needs nothing from the agent: GRUB already boots the old default.
+//
+// The host is rebooted by this file only through the wrapper (kernel-reboot, kernel-revert), and only for a staged step.
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"regexp"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// OpKernelStep is the signed op class that STAGES a kernel set on a ring-1 box (it never reboots: the night leg does,
+// once the household was told). CC may sign it until the first paying customer (R-530 ruling).
+const OpKernelStep = "os_kernel_step"
+
+// DefaultKernelJudgeWait is how long a one-shot boot may take to come back healthy before the agent reverts it ONCE.
+// Measured 2026-10-07 (`audits/kernel-lane-2026-10-07/B/`): every container healthy 68 s after a reboot on demo-felhom,
+// 272 s on demo-hp; 20 minutes stays under the hub's 45-minute host_stale (a box that never comes back alarms after it).
+const DefaultKernelJudgeWait = 20 * time.Minute
+
+var kverRE = regexp.MustCompile(`^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$`)
+
+// KernelView is the wrapper's kernel object (felhom-os-apply Kernel.view).
+type KernelView struct {
+	Running        string  `json:"running"`
+	Default        string  `json:"default"`
+	Flag           *string `json:"flag"`
+	Phase          string  `json:"phase"`
+	From           string  `json:"from"`
+	To             string  `json:"to"`
+	SelfRevertUsed bool    `json:"self_revert_used"`
+	Reason         string  `json:"reason"`
+	VMID           int     `json:"vmid"` // the customer guest the step was staged for (the health rule's guest)
+}
+
+// kernelReportRing is the ring an after-boot report carries. In the first second after a boot the agent has not
+// fetched the hub's block yet, and Block() then answers ring 1 — so a ring-0 box's „judging" report said ring 1
+// (seen on demo-felhom, 2026-10-08 night, `audits/kernel-night-2026-10-07/readback/`). Order: the fetched block; the
+// block the daemon saved on disk before the reboot (R-866); ring 1 as before. A label only: the hub's approval reads its
+// own ring list. Pinned by TestKernelReportRing_BeforeFirstFetch.
+func (l *Leg) kernelReportRing() int {
+	l.mu.Lock()
+	fetched := l.block
+	l.mu.Unlock()
+	if fetched != nil {
+		return fetched.Ring
+	}
+	if b, _, ok := LoadSavedBlock(l.planDir()); ok && b != nil {
+		return b.Ring
+	}
+	return 1
+}
+
+func parseKernel(raw json.RawMessage) KernelView {
+	var v KernelView
+	_ = json.Unmarshal(raw, &v)
+	return v
+}
+
+// kernelPlan is one kernel-layer wrapper call.
+func kernelPlan(mode string, vmid int, extra map[string]any) map[string]any {
+	p := map[string]any{"release_id": "kernel", "layer": LayerKernel, "lane": "slow", "vmid": vmid, "mode": mode,
+		"packages": []Package{}}
+	for k, v := range extra {
+		p[k] = v
+	}
+	return p
+}
+
+// KernelStatus reads the kernel lane's state (read only).
+func (l *Leg) KernelStatus(ctx context.Context, vmid int) (KernelView, error) {
+	wr, err := l.call(ctx, "kstatus"+l.now().UTC().Format("150405"), kernelPlan("kernel-status", vmid, nil))
+	if err != nil {
+		return KernelView{}, err
+	}
+	if wr.refused() {
+		return KernelView{}, fmt.Errorf("kernel-status refused: %s", wr.Refused)
+	}
+	return parseKernel(wr.Kernel), nil
+}
+
+// kernelDue reports whether tonight's leg may take a kernel step, and why not.
+func kernelDue(blk hub.WireOSUpdate, trigger string) (bool, string) {
+	switch {
+	case trigger != "night":
+		return false, "a kernel step runs only in the night leg (never a debug pass)"
+	case blk.Kernel == nil:
+		return false, "the hub names no kernel step for this box"
+	case !blk.Enabled:
+		return false, "OS updates are switched off for this box"
+	case !kverRE.MatchString(blk.Kernel.Kver):
+		return false, "the hub's kernel " + blk.Kernel.Kver + " is not a kernel version"
+	case !blk.Kernel.Tonight:
+		return false, "the household has not been told about tonight (no mail, no step — `09` §3 decision 172)"
+	}
+	return true, ""
+}
+
+// runKernel is the night leg's last step. It returns the stage report (Layer "" when nothing ran). On success the box
+// is rebooting when it returns.
+func (l *Leg) runKernel(ctx context.Context, runID string, vmid int, trigger string, blk hub.WireOSUpdate) Report {
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid, "trigger", trigger, "ring", blk.Ring)
+	if ok, why := kernelDue(blk, trigger); !ok {
+		lg.Info("osupdate: kernel step skipped — " + why)
+		return Report{}
+	}
+	want := blk.Kernel.Kver
+	st, err := l.KernelStatus(ctx, vmid)
+	if err != nil {
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "apply", Outcome: "failed", HealthReason: "kernel status unreadable: " + err.Error()})
+	}
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid, Mode: "apply", ReleaseID: want}
+	switch {
+	case st.Phase == "staged" && st.To == want:
+		lg.Info("osupdate: kernel step — a staged kernel waits for tonight", "from", st.From, "to", st.To)
+		rep.Outcome, rep.Healthy = "staged", true
+	case blk.Ring != 0:
+		lg.Info("osupdate: kernel step skipped — ring 1 boots only a kernel a signed os_kernel_step staged", "phase", st.Phase, "staged", st.To, "want", want)
+		return Report{}
+	default:
+		// R-898: EXACTLY the kernel the household was told about — never "whatever is pending tonight" (the sources can
+		// offer a newer one by night; the step then refused, R23, and the night was lost). A version no longer
+		// installable is refused by the wrapper before any change (R7) and the hub tells the household again.
+		wr, cerr := l.call(ctx, runID, kernelPlan("apply", vmid, map[string]any{"release_id": "ring0-" + runID,
+			"select": "listed", "packages": KernelSet(want), "expect_kver": want, "run_id": runID, "trigger": trigger,
+			"ring": blk.Ring}))
+		rep.unsent = reportFile(l.planDir(), runID, LayerKernel, "apply")
+		rep.Kernel = rawOrNil(wr.Kernel)
+		switch {
+		case cerr != nil:
+			rep.Outcome, rep.HealthReason = "failed", cerr.Error()
+			return l.finish(ctx, lg, rep)
+		case wr.refused():
+			rep.Outcome, rep.Refused = "refused", wr.Refused
+			return l.finish(ctx, lg, rep)
+		case wr.failed():
+			rep.Outcome, rep.Refused = "failed", wr.Failed
+			return l.finish(ctx, lg, rep)
+		case wr.OutcomeHint == "nothing" || len(wr.Upgraded) == 0:
+			rep.Outcome, rep.Healthy = "nothing", true
+			return l.finish(ctx, lg, rep)
+		}
+		rep.Outcome, rep.Healthy, rep.Upgraded, rep.Authority, rep.PassSeconds = "staged", true, wr.Upgraded, wr.Authority, wr.PassSeconds
+		rep.RebootNeeded = true
+	}
+	rep = l.finish(ctx, lg, rep) // the hub hears "staged" BEFORE the box goes down
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-reboot", vmid, nil))
+	switch {
+	case err != nil:
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "kernel-reboot", ReleaseID: want, Outcome: "failed", HealthReason: "kernel-reboot: " + err.Error()})
+	case wr.refused() || wr.failed():
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "kernel-reboot", ReleaseID: want, Outcome: "refused", Refused: firstRaw(wr.Refused, wr.Failed),
+			Kernel: rawOrNil(wr.Kernel)})
+	}
+	lg.Warn("osupdate: kernel step — the box restarts now for its one-shot boot", "to", want)
+	return rep
+}
+
+func firstRaw(a, b json.RawMessage) json.RawMessage {
+	if r := rawOrNil(a); r != nil {
+		return r
+	}
+	return rawOrNil(b)
+}
+
+// KernelJudge is what KernelAfterBoot needs besides the leg: the hub reachability probe is the "judging" report itself.
+type KernelJudge struct {
+	Wait time.Duration // default DefaultKernelJudgeWait
+	Poll time.Duration // default 30 s
+}
+
+// KernelAfterBoot runs once at daemon start: what became of a kernel step across the boot. On the new kernel it judges
+// the boot (blocking up to the wait — run it in a goroutine). vmid 0 = the guest the step recorded (it may not run yet).
+func (l *Leg) KernelAfterBoot(ctx context.Context, vmid int, j KernelJudge) Report {
+	runID := "boot-" + l.now().UTC().Format("20060102T150405Z")
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid)
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-boot", vmid, nil))
+	if err != nil {
+		lg.Warn("osupdate: kernel after-boot check failed", "err", err)
+		return Report{}
+	}
+	if wr.refused() {
+		lg.Info("osupdate: kernel after-boot check refused (an older wrapper, or a BYO host)", "refused", string(wr.Refused))
+		return Report{}
+	}
+	v := parseKernel(wr.Kernel)
+	if vmid <= 0 {
+		vmid = v.VMID // after a boot the guest may not run yet — the step's own record names it
+	}
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid, Mode: "kernel-boot",
+		ReleaseID: v.To, Kernel: rawOrNil(wr.Kernel)}
+	switch wr.KernelEvent {
+	case "fell_back":
+		rep.Outcome, rep.HealthReason = "fell_back", v.Reason
+		lg.Warn("osupdate: kernel step FELL BACK — the new kernel did not come up; the box runs the old one", "from", v.From, "to", v.To)
+		return l.finish(ctx, lg, rep)
+	case "self_reverted":
+		rep.Outcome, rep.HealthReason = "self_reverted", v.Reason
+		lg.Warn("osupdate: kernel step SELF-REVERTED — back on the old kernel", "from", v.From, "to", v.To, "reason", v.Reason)
+		return l.finish(ctx, lg, rep)
+	case "revert_failed":
+		rep.Outcome, rep.HealthReason = "revert_failed", v.Reason
+		lg.Error("osupdate: kernel self-revert came back on the NEW kernel — no second revert; the operator decides", "to", v.To)
+		return l.finish(ctx, lg, rep)
+	case "judging":
+		return l.judgeKernel(ctx, runID, vmid, v, wr.HealthBefore, j, lg)
+	}
+	return Report{}
+}
+
+// KernelVerdict is THE one-shot boot rule (R-836; pinned by TestKernelVerdict): the host health rule (`11` §8.2 —
+// the Proxmox daemons and the agent active, the customer guest running and its own rule passing, the tunnel running)
+// AND the box reached the hub since this boot.
+func KernelVerdict(before, after *Health, tunnel string, hubReached bool) (bool, string) {
+	if ok, why := HostHealthVerdict(before, after, tunnel); !ok {
+		return false, why
+	}
+	if !hubReached {
+		return false, "the box has not reached the hub since the boot"
+	}
+	return true, ""
+}
+
+func (l *Leg) judgeKernel(ctx context.Context, runID string, vmid int, v KernelView, before *Health, j KernelJudge, lg *slog.Logger) Report {
+	wait, poll := j.Wait, j.Poll
+	if wait <= 0 {
+		wait = DefaultKernelJudgeWait
+	}
+	if poll <= 0 {
+		poll = 30 * time.Second
+	}
+	lg.Info("osupdate: kernel step — judging the one-shot boot", "from", v.From, "to", v.To, "wait", wait.String())
+	start := l.now()
+	deadline := start.Add(wait)
+	hubReached := false
+	var why string
+	for {
+		if !hubReached && l.Hub != nil {
+			// the hub's reachability IS this report reaching it (and the operator sees the box is back on the new kernel)
+			body, _ := json.Marshal(Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+				Mode: "kernel-boot", ReleaseID: v.To, Outcome: "judging", Kernel: mustRaw(v)})
+			rctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+			if err := l.Hub.PostOSReport(rctx, body); err == nil {
+				hubReached = true
+				lg.Info("osupdate: kernel step — the box reached the hub on the new kernel", "after", l.now().Sub(start).Round(time.Second).String())
+			}
+			cancel()
+		}
+		var h *Health
+		hr, err := l.call(ctx, runID, kernelPlan("health", vmid, nil))
+		switch {
+		case err != nil:
+			why = "no health reading: " + err.Error()
+		case hr.refused():
+			why = "no health reading: " + string(hr.Refused)
+		default:
+			h = hr.Health
+		}
+		if h != nil {
+			t := hub.TunnelUnknown
+			if l.Tunnel != nil {
+				t, _ = l.Tunnel.Status(ctx)
+			}
+			var ok bool
+			ok, why = KernelVerdict(before, h, t, hubReached)
+			if ok {
+				return l.kernelGood(ctx, runID, vmid, v, start, lg)
+			}
+		}
+		if !l.now().Before(deadline) || ctx.Err() != nil {
+			break
+		}
+		l.sleep(ctx, poll)
+	}
+	if ctx.Err() != nil {
+		lg.Warn("osupdate: kernel judging stopped (the agent is stopping) — the next start judges again", "reason", why)
+		return Report{}
+	}
+	// not healthy by the deadline: tell the hub (best effort), then ONE self-revert into the old kernel
+	rep := l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+		Mode: "kernel-revert", ReleaseID: v.To, Outcome: "health_failed", HealthReason: why + " — reverting to " + v.From,
+		Kernel: mustRaw(v)})
+	lg.Error("osupdate: kernel step — the one-shot boot is NOT healthy; restarting ONCE into the old kernel", "reason", why,
+		"waited", wait.String(), "from", v.From, "to", v.To)
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-revert", vmid, map[string]any{"reason": truncate(why, 280)}))
+	if err != nil || wr.refused() || wr.failed() {
+		lg.Error("osupdate: kernel self-revert did not start — the box stays on the new kernel; the operator decides",
+			"err", err, "refused", string(firstRaw(wr.Refused, wr.Failed)))
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+			Mode: "kernel-revert", ReleaseID: v.To, Outcome: "revert_failed", Refused: firstRaw(wr.Refused, wr.Failed),
+			HealthReason: "the self-revert did not start"})
+	}
+	return rep
+}
+
+func (l *Leg) kernelGood(ctx context.Context, runID string, vmid int, v KernelView, start time.Time, lg *slog.Logger) Report {
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-good", vmid, nil))
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid, Mode: "kernel-good",
+		ReleaseID: v.To}
+	switch {
+	case err != nil:
+		rep.Outcome, rep.HealthReason = "failed", "kernel-good: "+err.Error()
+	case wr.refused() || wr.failed():
+		rep.Outcome, rep.Refused, rep.HealthReason = "failed", firstRaw(wr.Refused, wr.Failed), "kernel-good did not move the default"
+	default:
+		rep.Outcome, rep.Healthy = "applied", true
+		rep.HealthReason = fmt.Sprintf("healthy %s after the agent started; the new kernel is the default", l.now().Sub(start).Round(time.Second))
+	}
+	rep.Kernel = rawOrNil(wr.Kernel)
+	lg.Info("osupdate: kernel step — "+rep.Outcome, "to", v.To, "reason", rep.HealthReason)
+	return l.finish(ctx, lg, rep)
+}
+
+func mustRaw(v any) json.RawMessage {
+	b, _ := json.Marshal(v)
+	return b
+}
+
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n]
+}
+
+// KernelSet is the package set that installs exactly kver (R-898; the hub's kernelSet, field-exact): the series
+// meta-package and the signed image, both at the kernel's own version. Proxmox keeps old kernel versions in its archive.
+// nil for a string that is not a kernel version.
+func KernelSet(kver string) []Package {
+	m := kverSeriesRE.FindStringSubmatch(kver)
+	if m == nil {
+		return nil
+	}
+	v := kver[:len(kver)-len("-pve")]
+	return []Package{{Name: "proxmox-kernel-" + m[1], Version: v, Origin: PVEOrigin},
+		{Name: "proxmox-kernel-" + kver + "-signed", Version: v, Origin: PVEOrigin}}
+}
+
+var kverSeriesRE = regexp.MustCompile(`^([0-9]+\.[0-9]+)\.[0-9]+-[0-9]+-pve$`)
+
+// KernelStepParams are a signed os_kernel_step's params: the exact kernel set (the wrapper compares it with the plan).
+type KernelStepParams struct {
+	ReleaseID string    `json:"release_id"`
+	Packages  []Package `json:"packages"`
+	Kver      string    `json:"kver"`
+	VMID      int       `json:"vmid,omitempty"`
+}
+
+// KernelStepExecutor STAGES a verified os_kernel_step (signedjobs.Executor) under the heavy-op gate. It never reboots:
+// the night leg reboots a staged kernel on a night the household was told about.
+type KernelStepExecutor struct {
+	Leg   *Leg
+	Guest func(ctx context.Context) (int, error)
+	Gate  func(ctx context.Context) (release func(), err error)
+}
+
+// Execute implements signedjobs.Executor.
+func (e KernelStepExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
+	if op != OpKernelStep {
+		return signedjobs.ErrNoExecutor
+	}
+	so, ok := signedjobs.SignedOpFrom(ctx)
+	if !ok {
+		return fmt.Errorf("os_kernel_step: no signed envelope in the context — the wrapper could not verify it")
+	}
+	var p KernelStepParams
+	if err := json.Unmarshal(params, &p); err != nil || len(p.Packages) == 0 || !kverRE.MatchString(p.Kver) {
+		return fmt.Errorf("os_kernel_step: params must name the kernel set and its kver: %v", err)
+	}
+	vmid := p.VMID
+	if vmid == 0 {
+		if e.Guest == nil {
+			return fmt.Errorf("os_kernel_step: no vmid and no guest finder")
+		}
+		v, err := e.Guest(ctx)
+		if err != nil {
+			return fmt.Errorf("os_kernel_step: find the customer guest: %w", err)
+		}
+		vmid = v
+	}
+	if e.Gate != nil {
+		release, err := e.Gate(ctx)
+		if err != nil {
+			return fmt.Errorf("os_kernel_step: heavy-op gate busy (a backup or restore-test runs): %w", err)
+		}
+		defer release()
+	}
+	rep := e.Leg.StageKernelSigned(ctx, vmid, p, so.Blob, string(so.Sig))
+	if rep.Outcome == "staged" || rep.Outcome == "nothing" {
+		return nil
+	}
+	return fmt.Errorf("os_kernel_step: %s (%s) %s", rep.Outcome, rep.HealthReason, string(rep.Refused))
+}
+
+// StageKernelSigned stages a signed kernel set (ring 1): install + flag, no reboot.
+func (l *Leg) StageKernelSigned(ctx context.Context, vmid int, p KernelStepParams, blob []byte, sig string) Report {
+	unlock := l.lockPass(true)
+	defer unlock()
+	l.sendUnsentLocked(ctx) // R-868
+	runID := l.now().UTC().Format("20060102T150405Z")
+	rid := p.ReleaseID
+	if rid == "" {
+		rid = "signed-" + runID
+	}
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid, "trigger", "signed", "release", rid)
+	wr, err := l.call(ctx, runID, kernelPlan("apply", vmid, map[string]any{"release_id": rid, "select": "listed",
+		"packages": p.Packages, "expect_kver": p.Kver, "run_id": runID, "trigger": "signed", "ring": l.Block().Ring,
+		"signed": map[string]string{"blob_b64": base64.StdEncoding.EncodeToString(blob), "sig": sig}}))
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "signed", Ring: l.Block().Ring, VMID: vmid, Mode: "apply",
+		ReleaseID: rid, Kernel: rawOrNil(wr.Kernel), unsent: reportFile(l.planDir(), runID, LayerKernel, "apply")}
+	switch {
+	case err != nil:
+		rep.Outcome, rep.HealthReason = "failed", err.Error()
+	case wr.refused():
+		rep.Outcome, rep.Refused = "refused", wr.Refused
+	case wr.failed():
+		rep.Outcome, rep.Refused = "failed", wr.Failed
+	case wr.OutcomeHint == "nothing" || len(wr.Upgraded) == 0:
+		rep.Outcome, rep.Healthy = "nothing", true
+	default:
+		rep.Outcome, rep.Healthy, rep.Upgraded, rep.Authority, rep.PassSeconds = "staged", true, wr.Upgraded, wr.Authority, wr.PassSeconds
+		rep.RebootNeeded = true
+	}
+	return l.finish(ctx, lg, rep)
+}

internal/osupdate/kernel_test.go

@@ -0,0 +1,328 @@
+package osupdate
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// ---- the kernel lane (R-836, `09` §3 decision 172, `11` §5.11) ----
+
+const kOld, kNew = "7.0.2-6-pve", "7.0.14-22-pve"
+
+func kview(phase string) json.RawMessage {
+	return mustRaw(KernelView{Running: kOld, Default: kOld, Phase: phase, From: kOld, To: kNew, VMID: 9201})
+}
+
+func tonight(ring int) *hub.WireOSUpdate {
+	return &hub.WireOSUpdate{Ring: ring, Enabled: true, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: true}}
+}
+
+func kernelCalls(w *fakeWrapper) []string {
+	var m []string
+	for _, p := range w.plans {
+		if p["layer"] == LayerKernel {
+			m = append(m, p["mode"].(string))
+		}
+	}
+	return m
+}
+
+// Ring 0, a told night: after the healthy host step the leg stages the pending kernel (select pending-kernel, the
+// kernel the household was told about), tells the hub "staged", THEN reboots — the kernel step ends the night.
+func TestKernel_Ring0ToldNightStagesThenReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{
+		"kernel-status": {{Kernel: kview("none")}},
+		"apply":         {{Upgraded: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22"}}, Authority: "ring0", Kernel: kview("staged")}},
+		"kernel-reboot": {{Kernel: kview("oneshot")}},
+	}}
+	l, h := newLeg(t, w, tonight(0))
+	p := l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status,apply,kernel-reboot" {
+		t.Fatalf("kernel calls = %s", got)
+	}
+	var ap map[string]any
+	for _, x := range w.plans {
+		if x["layer"] == LayerKernel && x["mode"] == "apply" {
+			ap = x
+		}
+	}
+	// R-898: EXACTLY the told kernel — the listed set derived from it, never "pending" (red before the fix: select was
+	// pending-kernel, so a newer kernel in the sources by night was refused R23 and the night was lost)
+	pk, _ := json.Marshal(ap["packages"])
+	if ap["select"] != "listed" || ap["expect_kver"] != kNew || ap["lane"] != "slow" ||
+		string(pk) != `[{"name":"proxmox-kernel-7.0","origin":"Proxmox Debian Repository","version":"7.0.14-22"},{"name":"proxmox-kernel-7.0.14-22-pve-signed","origin":"Proxmox Debian Repository","version":"7.0.14-22"}]` {
+		t.Fatalf("stage plan = %v (packages %s)", ap, pk)
+	}
+	if p.Kernel.Outcome != "staged" || !p.Kernel.Healthy {
+		t.Fatalf("kernel report = %+v", p.Kernel)
+	}
+	last := h.reports[len(h.reports)-1]
+	if last.Layer != LayerKernel || last.Outcome != "staged" {
+		t.Fatalf("the hub must hear 'staged' before the reboot: %+v", h.reports)
+	}
+	// the kernel step is the LAST wrapper call of the night
+	if lp := w.plans[len(w.plans)-1]; lp["layer"] != LayerKernel || lp["mode"] != "kernel-reboot" {
+		t.Fatalf("the reboot must end the night, last call = %v", lp)
+	}
+}
+
+// No mail, no step: a kernel the household was NOT told about never runs; nor in a debug pass; nor without a block.
+// COMPANION RED-PROOF (observed): drop the `!blk.Kernel.Tonight` case in kernelDue → the first sub-case fails.
+func TestKernel_NoMailNoStep(t *testing.T) {
+	cases := map[string]struct {
+		blk     *hub.WireOSUpdate
+		trigger string
+	}{
+		"not told":   {&hub.WireOSUpdate{Ring: 0, Enabled: true, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: false}}, "night"},
+		"debug pass": {tonight(0), "debug"},
+		"no block":   {&hub.WireOSUpdate{Ring: 0, Enabled: true}, "night"},
+		"switch off": {&hub.WireOSUpdate{Ring: 0, Enabled: false, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: true}}, "night"},
+		"bad kver":   {&hub.WireOSUpdate{Ring: 0, Enabled: true, Kernel: &hub.WireKernelStep{Kver: "7.0; reboot", Tonight: true}}, "night"},
+	}
+	for name, c := range cases {
+		w := &fakeWrapper{t: t}
+		l, _ := newLeg(t, w, c.blk)
+		p := l.Run(context.Background(), 9201, c.trigger)
+		if len(kernelCalls(w)) != 0 || p.Kernel.Layer != "" {
+			t.Fatalf("%s: a kernel step ran: %v", name, kernelCalls(w))
+		}
+	}
+}
+
+// The kernel step needs a healthy host step on an appliance, and a healthy Proxmox step when one ran.
+func TestKernel_SkippedWithoutHealthyEarlierSteps(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, tonight(0))
+	l.Appliance = false
+	l.Run(context.Background(), 9201, "night")
+	if len(kernelCalls(w)) != 0 {
+		t.Fatalf("a BYO box took a kernel step: %v", kernelCalls(w))
+	}
+	w2 := &fakeWrapper{t: t, applyRep: map[string]WrapperReport{LayerPVE: {Upgraded: []Package{{Name: "pve-manager", Version: "9.2.21"}},
+		PVEManager: "9.2.2"}}} // pveversion still old → the pve step is unhealthy
+	l2, _ := newLeg(t, w2, tonight(0))
+	l2.Run(context.Background(), 9201, "night")
+	if len(kernelCalls(w2)) != 0 {
+		t.Fatalf("a kernel step ran after an unhealthy Proxmox step: %v", kernelCalls(w2))
+	}
+}
+
+// Ring 1 reboots only a kernel a signed job staged — never stages one itself in the night leg.
+func TestKernel_Ring1RebootsOnlyASignedStage(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("none")}}}}
+	l, _ := newLeg(t, w, tonight(1))
+	l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status" {
+		t.Fatalf("ring 1 without a staged kernel: calls = %s", got)
+	}
+	w2 := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("staged")}},
+		"kernel-reboot": {{Kernel: kview("oneshot")}}}}
+	l2, _ := newLeg(t, w2, tonight(1))
+	p := l2.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w2), ","); got != "kernel-status,kernel-reboot" || p.Kernel.Outcome != "staged" {
+		t.Fatalf("ring 1 with a staged kernel: calls = %s report = %+v", got, p.Kernel)
+	}
+}
+
+// A refused stage never reboots.
+func TestKernel_RefusedStageNeverReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("none")}},
+		"apply": {{Refused: json.RawMessage(`{"code":"R20","reason":"/boot/efi is not a mounted vfat ESP"}`)}}}}
+	l, h := newLeg(t, w, tonight(0))
+	p := l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status,apply" || p.Kernel.Outcome != "refused" {
+		t.Fatalf("calls = %s report = %+v", got, p.Kernel)
+	}
+	if last := h.reports[len(h.reports)-1]; last.Layer != LayerKernel || last.Outcome != "refused" {
+		t.Fatalf("the hub must hear the refusal: %+v", last)
+	}
+}
+
+// THE one-shot boot rule: the host rule AND the hub reached. COMPANION RED-PROOF (observed): drop the hubReached
+// check in KernelVerdict → the second case fails.
+func TestKernelVerdict(t *testing.T) {
+	if ok, why := KernelVerdict(hostOK(), hostOK(), hub.TunnelRunning, true); !ok {
+		t.Fatalf("a healthy boot read unhealthy: %s", why)
+	}
+	if ok, why := KernelVerdict(hostOK(), hostOK(), hub.TunnelRunning, false); ok || !strings.Contains(why, "hub") {
+		t.Fatalf("a box that has not reached the hub must not pass: ok=%v %q", ok, why)
+	}
+	down := hostOK()
+	down.GuestRunning = new(bool)
+	if ok, _ := KernelVerdict(hostOK(), down, hub.TunnelRunning, true); ok {
+		t.Fatal("a guest that does not run must fail")
+	}
+	if ok, _ := KernelVerdict(hostOK(), hostOK(), hub.TunnelUnknown, true); ok {
+		t.Fatal("an unknown tunnel must fail (the host rule)")
+	}
+}
+
+func judgingLeg(t *testing.T, w *fakeWrapper) (*Leg, *fakeHub) {
+	if w.kernelRep == nil {
+		w.kernelRep = map[string][]WrapperReport{}
+	}
+	if _, ok := w.kernelRep["kernel-boot"]; !ok {
+		w.kernelRep["kernel-boot"] = []WrapperReport{{KernelEvent: "judging", Kernel: mustRaw(KernelView{Running: kNew,
+			Default: kOld, Phase: "judging", From: kOld, To: kNew, VMID: 9201}), HealthBefore: hostOK()}}
+	}
+	return newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+}
+
+// A healthy one-shot boot: the hub hears "judging", then kernel-good, then "applied".
+func TestKernelAfterBoot_HealthyBecomesTheDefault(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-good": {{Kernel: kview("good")}}}}
+	l, h := judgingLeg(t, w)
+	r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 10 * time.Minute, Poll: 30 * time.Second})
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-boot,health,kernel-good" {
+		t.Fatalf("calls = %s", got)
+	}
+	if r.Outcome != "applied" || !r.Healthy {
+		t.Fatalf("report = %+v", r)
+	}
+	if len(h.reports) != 2 || h.reports[0].Outcome != "judging" || h.reports[1].Outcome != "applied" {
+		t.Fatalf("hub reports = %+v", h.reports)
+	}
+	if w.plans[1]["vmid"] != float64(9201) {
+		t.Fatalf("the health reading must use the step's own guest, got %v", w.plans[1]["vmid"])
+	}
+}
+
+// An unhealthy one-shot boot: wait the full judge time, tell the hub, then ONE kernel-revert.
+// COMPANION RED-PROOF (observed): return before the kernel-revert call in judgeKernel → "calls" fails.
+func TestKernelAfterBoot_UnhealthyRevertsOnceAfterTheWait(t *testing.T) {
+	down := hostOK()
+	down.GuestRunning = new(bool)
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"health": {{Health: down}},
+		"kernel-revert": {{Kernel: kview("reverting")}}}}
+	l, h := judgingLeg(t, w)
+	start := l.now()
+	r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 10 * time.Minute, Poll: time.Minute})
+	calls := kernelCalls(w)
+	if calls[len(calls)-1] != "kernel-revert" || strings.Count(strings.Join(calls, ","), "kernel-revert") != 1 {
+		t.Fatalf("calls = %v", calls)
+	}
+	if waited := l.now().Sub(start); waited < 10*time.Minute {
+		t.Fatalf("reverted after %s — before the judge wait", waited)
+	}
+	if r.Outcome != "health_failed" || !strings.Contains(r.HealthReason, "not running") {
+		t.Fatalf("report = %+v", r)
+	}
+	if last := h.reports[len(h.reports)-1]; last.Outcome != "health_failed" {
+		t.Fatalf("the hub must hear health_failed before the revert reboot: %+v", h.reports)
+	}
+	for _, p := range w.plans {
+		if p["mode"] == "kernel-revert" && !strings.Contains(p["reason"].(string), "not running") {
+			t.Fatalf("the revert must carry the reason: %v", p)
+		}
+	}
+}
+
+// A box that never reaches the hub is not "healthy" — it reverts too.
+func TestKernelAfterBoot_NoHubMeansRevert(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-revert": {{Kernel: kview("reverting")}}}}
+	l, _ := judgingLeg(t, w)
+	l.Hub = unreachableHub{}
+	l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 5 * time.Minute, Poll: time.Minute})
+	if c := kernelCalls(w); c[len(c)-1] != "kernel-revert" {
+		t.Fatalf("calls = %v", c)
+	}
+}
+
+type unreachableHub struct{}
+
+func (unreachableHub) PostOSReport(context.Context, []byte) error { return context.DeadlineExceeded }
+
+// What kernel-boot found becomes the hub's outcome, with no judging and no reboot.
+func TestKernelAfterBoot_FallBackAndRevertResultsAreReported(t *testing.T) {
+	for ev, want := range map[string]string{"fell_back": "fell_back", "self_reverted": "self_reverted", "revert_failed": "revert_failed"} {
+		w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-boot": {{KernelEvent: ev,
+			Kernel: mustRaw(KernelView{Running: kOld, Default: kOld, Phase: ev, From: kOld, To: kNew, Reason: "r", VMID: 9201})}}}}
+		l, h := judgingLeg(t, w)
+		r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{})
+		if r.Outcome != want || len(h.reports) != 1 || h.reports[0].Outcome != want {
+			t.Fatalf("%s: report %+v hub %+v", ev, r, h.reports)
+		}
+		if got := strings.Join(kernelCalls(w), ","); got != "kernel-boot" {
+			t.Fatalf("%s: calls = %s", ev, got)
+		}
+	}
+	// nothing to do → nothing reported
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-boot": {{KernelEvent: "none", Kernel: kview("good")}}}}
+	l, h := judgingLeg(t, w)
+	if r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{}); r.Layer != "" || len(h.reports) != 0 {
+		t.Fatalf("an ordinary boot must report nothing: %+v %+v", r, h.reports)
+	}
+}
+
+// The signed executor STAGES (listed + the raw envelope + the kver) and never reboots.
+func TestKernelStepExecutor_StagesNeverReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"apply": {{Upgraded: []Package{{Name: "proxmox-kernel-7.0",
+		Version: "7.0.14-22"}}, Authority: "signed", Kernel: kview("staged")}}}}
+	l, h := newLeg(t, w, &hub.WireOSUpdate{Ring: 1, Enabled: true})
+	e := KernelStepExecutor{Leg: l, Guest: func(context.Context) (int, error) { return 9201, nil }}
+	params, _ := json.Marshal(KernelStepParams{ReleaseID: "os-kernel-1", Kver: kNew,
+		Packages: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22", Origin: PVEOrigin}}})
+	ctx := signedjobs.WithSignedOp(context.Background(), &reconcile.SignedOp{Blob: []byte(`{"op":"os_kernel_step"}`), Sig: []byte("SIG")})
+	if err := e.Execute(ctx, OpKernelStep, params); err != nil {
+		t.Fatal(err)
+	}
+	pp := w.plans[len(w.plans)-1]
+	sg, _ := pp["signed"].(map[string]any)
+	if pp["mode"] != "apply" || pp["select"] != "listed" || pp["expect_kver"] != kNew || sg == nil ||
+		sg["blob_b64"] != base64.StdEncoding.EncodeToString([]byte(`{"op":"os_kernel_step"}`)) {
+		t.Fatalf("plan = %v", pp)
+	}
+	if got := strings.Join(kernelCalls(w), ","); got != "apply" {
+		t.Fatalf("a signed stage must never reboot: %s", got)
+	}
+	if len(h.reports) != 1 || h.reports[0].Outcome != "staged" {
+		t.Fatalf("hub = %+v", h.reports)
+	}
+	if err := e.Execute(context.Background(), OpKernelStep, params); err == nil {
+		t.Fatal("no envelope must refuse")
+	}
+	bad, _ := json.Marshal(KernelStepParams{Kver: "x", Packages: []Package{{Name: "a"}}})
+	if err := e.Execute(ctx, OpKernelStep, bad); err == nil {
+		t.Fatal("a bad kver must refuse")
+	}
+	if err := e.Execute(ctx, OpPVEStep, params); err != signedjobs.ErrNoExecutor {
+		t.Fatalf("another op must pass through the chain: %v", err)
+	}
+}
+
+// os_kernel_step is never benign.
+func TestKernelStep_IsDestructiveClass(t *testing.T) {
+	if reconcile.Classify(reconcile.ClassOSKernelStep, reconcile.Provenance{}) != reconcile.Destructive {
+		t.Fatal("os_kernel_step must be destructive-class (signed, operational key)")
+	}
+}
+
+// A kept stage report (the agent was killed mid-stage) reaches the hub as "staged" with its kernel view.
+func TestKernel_KeptStageReportIsStaged(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, tonight(0))
+	ring := 0
+	rep := l.reportFromKept(context.Background(), WrapperReport{Layer: LayerKernel, Mode: "apply", Ring: &ring,
+		Upgraded: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22"}}, Kernel: kview("staged")}, "/x/report-r-kernel-apply.json")
+	if rep.Outcome != "staged" || !rep.Healthy || len(rep.Kernel) == 0 {
+		t.Fatalf("kept = %+v", rep)
+	}
+}
+
+func TestKernelSet(t *testing.T) {
+	if got := KernelSet("7.0.14-20-pve"); len(got) != 2 || got[0].Name != "proxmox-kernel-7.0" || got[0].Version != "7.0.14-20" ||
+		got[1].Name != "proxmox-kernel-7.0.14-20-pve-signed" {
+		t.Fatalf("%+v", got)
+	}
+	if KernelSet("7.0; reboot") != nil || KernelSet("") != nil {
+		t.Fatal("a non-kernel string must give no set")
+	}
+}

internal/osupdate/leg.go

@@ -45,6 +45,9 @@ const (
 	// LayerPVE is the HOST's Proxmox userspace packages — slow lane (R-812 option A, `09` §3 decision 163, `11` §5.10):
 	// ring 0 in the night leg after a healthy host step, ring 1 only inside a signed os_pve_step. Never a kernel.
 	LayerPVE = "pve"
+	// LayerKernel is the HOST's kernel — the kernel lane (R-836, `09` §3 decision 172, `11` §5.11): a one-shot boot of
+	// the new kernel through the ESP flag, the default moved only after a healthy boot (kernel.go).
+	LayerKernel = "kernel"
 )
 
 // PVEOrigin is the origin apt prints for download.proxmox.com (the wrapper's PVE_ORIGIN); InstalledPVEOrigin is how
@@ -126,6 +129,11 @@ type WrapperReport struct {
 	OOMCheck json.RawMessage `json:"oom_check"`
 	// PVEManager: the pve layer — pveversion's pve-manager version after the step ("unknown" = unreadable).
 	PVEManager string `json:"pve_manager"`
+	// Kernel (R-836): the kernel layer's view {running, default, flag, phase, from, to, …}; KernelEvent what kernel-boot
+	// found after a boot; OutcomeHint "nothing" when no kernel was pending.
+	Kernel      json.RawMessage `json:"kernel"`
+	KernelEvent string          `json:"kernel_event"`
+	OutcomeHint string          `json:"outcome_hint"`
 	// R-868 (v0.144.0): the agent's ids, echoed from the plan, so a report kept on disk can be sent without the
 	// agent process that started the pass. ReleaseID / VMID were always in the report.
 	RunID     string `json:"run_id"`
@@ -168,6 +176,10 @@ type Report struct {
 	OOMCheck json.RawMessage `json:"oom_check,omitempty"`
 	// PVEManager: pve layer — pve-manager's version after the step (the hub's System page; R-812 option A).
 	PVEManager string `json:"pve_manager,omitempty"`
+	// Kernel: kernel layer — the wrapper's kernel view, byte for byte (running, default, flag, phase, from, to). The
+	// outcomes of this layer: staged | applied (the new kernel is the default) | fell_back | health_failed (self-revert
+	// started) | self_reverted | revert_failed | judging | nothing | refused | failed.
+	Kernel json.RawMessage `json:"kernel,omitempty"`
 
 	unsent string // R-868: the wrapper's kept copy of this pass's report — deleted once the hub has it
 }
@@ -500,7 +512,7 @@ func (l *Leg) call(ctx context.Context, runID string, plan map[string]any) (Wrap
 
 // Pass is one leg's reports; an empty Layer means the step did not run.
 type Pass struct {
-	Guest, Host, Docker, PVE Report
+	Guest, Host, Docker, PVE, Kernel Report
 }
 
 // Run is one pass: the guest layer, then (on an appliance, after a good guest step) the host layer, then (ring 0
@@ -542,6 +554,16 @@ func (l *Leg) Run(ctx context.Context, vmid int, trigger string) Pass {
 	default:
 		p.PVE = l.runPVE(ctx, g.RunID, vmid, trigger, blk, dockerOpts{})
 	}
+	// R-836 (`09` §3 decision 172): the kernel step ENDS the night — an appliance, after a healthy host step (and a
+	// healthy Proxmox step when one ran), only on a night the hub marks as told. It reboots the box. Pinned by TestKernel_*.
+	switch {
+	case !l.Appliance || h.Layer == "" || !okStep(h):
+		lg.Info("osupdate: kernel step skipped — no healthy host step this pass (an appliance only)", "appliance", l.Appliance, "host_outcome", h.Outcome)
+	case p.PVE.Layer != "" && !okStep(p.PVE):
+		lg.Warn("osupdate: kernel step skipped — the Proxmox step did not end healthy", "pve_outcome", p.PVE.Outcome)
+	default:
+		p.Kernel = l.runKernel(ctx, g.RunID, vmid, trigger, blk)
+	}
 	return p
 }
 

internal/osupdate/leg_test.go

@@ -25,6 +25,7 @@ type fakeWrapper struct {
 	plans       []map[string]any
 	keep        bool // R-868: like the real wrapper, keep an apply report beside the plan
 	pveGateHeld bool
+	kernelRep   map[string][]WrapperReport // R-836: per kernel-layer mode, successive answers (the last one repeats)
 }
 
 func yes() *bool { b := true; return &b }
@@ -52,9 +53,19 @@ func (f *fakeWrapper) Run(_ context.Context, name string, args ...string) ([]byt
 	f.plans = append(f.plans, plan)
 	layer := plan["layer"].(string)
 	ok := guestOK()
-	if layer == LayerHost || layer == LayerPVE {
+	if layer == LayerHost || layer == LayerPVE || layer == LayerKernel {
 		ok = hostOK()
 	}
+	if layer == LayerKernel {
+		if seq := f.kernelRep[plan["mode"].(string)]; len(seq) > 0 {
+			rep := seq[0]
+			if len(seq) > 1 {
+				f.kernelRep[plan["mode"].(string)] = seq[1:]
+			}
+			out, _ := json.Marshal(rep)
+			return []byte("OSAPPLY-REPORT " + string(out) + "\n"), []byte("os-apply: DONE rc=0\n"), nil
+		}
+	}
 	if layer == LayerPVE && plan["mode"] == "apply" {
 		f.pveGateHeld = pvegate.Stepping() // R-812: the /etc/pve write gate must be held while the pve step runs
 	}

internal/osupdate/r899_ring_test.go

@@ -0,0 +1,32 @@
+package osupdate
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+)
+
+// After a boot the agent has not fetched the hub's block yet; the after-boot kernel report must still carry the
+// box's real ring (seen 2026-10-08: a ring-0 box's „judging" report said ring 1). Red-proof: return Block().Ring
+// from kernelReportRing and the saved-block case fails with 1.
+func TestKernelReportRing_BeforeFirstFetch(t *testing.T) {
+	dir := t.TempDir()
+	l := &Leg{PlanDir: dir}
+	if got := l.kernelReportRing(); got != 1 {
+		t.Fatalf("nothing fetched, nothing saved: ring %d, want 1 (the old default)", got)
+	}
+	l.saveBlock(&hub.WireOSUpdate{Ring: 0, Enabled: true})
+	l2 := &Leg{PlanDir: dir} // a fresh daemon after the reboot: no block fetched yet
+	if got := l2.kernelReportRing(); got != 0 {
+		t.Fatalf("ring-0 block saved before the reboot: ring %d, want 0", got)
+	}
+	l2.SetBlock(&hub.WireOSUpdate{Ring: 1, Enabled: true})
+	if got := l2.kernelReportRing(); got != 1 {
+		t.Fatalf("a fetched block wins over the saved one: ring %d, want 1", got)
+	}
+	if _, err := os.Stat(filepath.Join(dir, SavedBlockFile)); err != nil {
+		t.Fatalf("saved block missing: %v", err)
+	}
+}

internal/osupdate/unsent.go

@@ -142,6 +142,17 @@ func (l *Leg) reportFromKept(ctx context.Context, wr WrapperReport, path string)
 	default:
 		rep.Outcome = "applied"
 	}
+	if wr.Layer == LayerKernel {
+		// a kernel STAGE changes nothing the box runs (the new kernel only boots once, at the night's reboot), so its
+		// kept copy needs no fresh health reading (R-836)
+		rep.Kernel = rawOrNil(wr.Kernel)
+		rep.Upgraded, rep.PassSeconds, rep.Authority = wr.Upgraded, wr.PassSeconds, wr.Authority
+		if rep.Outcome == "applied" {
+			rep.Outcome = "staged"
+		}
+		rep.Healthy, rep.HealthReason = rep.Outcome == "staged" || rep.Outcome == "nothing", prefix
+		return rep
+	}
 	rep.Upgraded, rep.PassSeconds = wr.Upgraded, wr.PassSeconds
 	rep.DockerEngine, rep.Authority, rep.Undo = wr.DockerEngine, wr.Authority, wr.Undo
 	rep.OOMCheck = rawOrNil(wr.OOMCheck)

internal/poweroff/state.go

@@ -0,0 +1,117 @@
+// Package poweroff keeps the box's record of a household-requested power-off (R-998, doc 14).
+//
+// One small JSON file in the agent's state dir. A record belongs to the boot it was made in (the
+// kernel's btime from /proc/stat), so:
+//   - "at most one accepted request per boot": Mark refuses when this boot already has a record;
+//   - the host report carries the record only while the box is still in that boot (Current), and
+//     the next boot's reports carry nothing — that absence is how the hub learns the box is back.
+//
+// Pinned by state_test.go.
+package poweroff
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+// ErrAlreadyThisBoot is Mark's refusal: a power-off was already accepted in the current boot.
+var ErrAlreadyThisBoot = errors.New("a power-off was already accepted in this boot")
+
+// ErrBootUnknown is Mark's refusal when the boot cannot be identified — fail closed: without it the
+// per-boot limit could not hold.
+var ErrBootUnknown = errors.New("cannot read the host's boot time")
+
+// Record is one accepted request.
+type Record struct {
+	RequestedAt time.Time `json:"requested_at"`
+	BootBtime   string    `json:"boot_btime"` // /proc/stat btime of the boot it was accepted in
+	VMID        int       `json:"vmid"`       // the guest whose controller asked
+}
+
+// State is the persisted record.
+type State struct {
+	path  string
+	btime func() string
+	mu    sync.Mutex
+}
+
+// New returns the state at path. btime returns the current boot's /proc/stat btime ("" = unknown).
+func New(path string, btime func() string) *State {
+	if btime == nil {
+		btime = ProcBtime
+	}
+	return &State{path: path, btime: btime}
+}
+
+// Current is the record made in THIS boot, or nil (none, another boot's, unreadable).
+func (s *State) Current() *Record {
+	if s == nil {
+		return nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	r := s.load()
+	b := s.btime()
+	if r == nil || b == "" || r.BootBtime != b {
+		return nil
+	}
+	return r
+}
+
+// Mark records an accepted request for this boot. It refuses a second one in the same boot.
+func (s *State) Mark(now time.Time, vmid int) (*Record, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	b := s.btime()
+	if b == "" {
+		return nil, ErrBootUnknown
+	}
+	if r := s.load(); r != nil && r.BootBtime == b {
+		return nil, ErrAlreadyThisBoot
+	}
+	r := &Record{RequestedAt: now.UTC().Truncate(time.Second), BootBtime: b, VMID: vmid}
+	data, _ := json.Marshal(r)
+	if err := os.MkdirAll(filepath.Dir(s.path), 0o750); err != nil {
+		return nil, fmt.Errorf("poweroff: state dir: %w", err)
+	}
+	tmp := s.path + ".tmp"
+	if err := os.WriteFile(tmp, data, 0o600); err != nil {
+		return nil, fmt.Errorf("poweroff: write: %w", err)
+	}
+	if err := os.Rename(tmp, s.path); err != nil {
+		return nil, fmt.Errorf("poweroff: rename: %w", err)
+	}
+	return r, nil
+}
+
+func (s *State) load() *Record {
+	data, err := os.ReadFile(s.path)
+	if err != nil {
+		return nil
+	}
+	var r Record
+	if json.Unmarshal(data, &r) != nil || r.BootBtime == "" {
+		return nil
+	}
+	return &r
+}
+
+// ProcBtime reads the boot time (seconds since the epoch, as text) from /proc/stat; "" when unreadable.
+func ProcBtime() string {
+	data, err := os.ReadFile("/proc/stat")
+	if err != nil {
+		return ""
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		if strings.HasPrefix(line, "btime ") {
+			return strings.TrimSpace(strings.TrimPrefix(line, "btime "))
+		}
+	}
+	return ""
+}

internal/poweroff/state_test.go

@@ -0,0 +1,41 @@
+package poweroff
+
+import (
+	"errors"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+// One accepted request per boot; the record is "current" only in the boot it was made in.
+func TestOnePerBootAndCurrentFollowsTheBoot(t *testing.T) {
+	boot := "1000"
+	s := New(filepath.Join(t.TempDir(), "poweroff.json"), func() string { return boot })
+	if s.Current() != nil {
+		t.Fatal("no record yet, Current must be nil")
+	}
+	now := time.Date(2026, 10, 13, 18, 0, 0, 0, time.UTC)
+	if _, err := s.Mark(now, 9201); err != nil {
+		t.Fatalf("first Mark: %v", err)
+	}
+	if r := s.Current(); r == nil || !r.RequestedAt.Equal(now) || r.VMID != 9201 {
+		t.Fatalf("Current after Mark = %+v", r)
+	}
+	if _, err := s.Mark(now.Add(time.Minute), 9201); !errors.Is(err, ErrAlreadyThisBoot) {
+		t.Fatalf("second Mark in the same boot: err = %v, want ErrAlreadyThisBoot", err)
+	}
+	boot = "2000" // the machine was switched on again
+	if s.Current() != nil {
+		t.Fatal("a record from the previous boot must not be current")
+	}
+	if _, err := s.Mark(now.Add(time.Hour), 9201); err != nil {
+		t.Fatalf("Mark in a new boot: %v", err)
+	}
+}
+
+func TestUnknownBootFailsClosed(t *testing.T) {
+	s := New(filepath.Join(t.TempDir(), "p.json"), func() string { return "" })
+	if _, err := s.Mark(time.Now(), 1); !errors.Is(err, ErrBootUnknown) {
+		t.Fatalf("err = %v, want ErrBootUnknown", err)
+	}
+}

internal/reconcile/classify.go

@@ -56,9 +56,19 @@ const (
 	// key) like os_docker_step; the root wrapper re-verifies the same signature itself.
 	ClassOSPVEStep OpClass = "os_pve_step"
 
+	// A kernel step on the host (R-836, `09` §3 decision 172, `11` §5.11) — ring 1: it STAGES a kernel (install + the
+	// one-shot flag; the night leg reboots it). Destructive-class (signed, operational key) like os_pve_step; the root
+	// wrapper re-verifies the same signature itself.
+	ClassOSKernelStep OpClass = "os_kernel_step"
+
 	// The config bundle (agent v0.143.0, R-840, `11` §5.4.2): the box's ROOT-OWNED files (sudoers, wrappers, units).
 	// Destructive-class (signed, operational key) like agent_update; the root wrapper re-verifies the signature itself.
 	ClassAgentConfigUpdate OpClass = "agent_config_update"
+
+	// The internal data place on an OLD one-disk box (agent v0.158.0, felhom.eu `16` §9): thin space on the system
+	// disk, made by the root helper felhom-internal-place. Destructive-class (signed, operational key): it is an
+	// operator act, never a household button, and no agent-internal provenance may start it.
+	ClassAddInternalPlace OpClass = "add_internal_place"
 )
 
 // Disposition is the classifier verdict.
@@ -127,7 +137,7 @@ func Classify(class OpClass, prov Provenance) Disposition {
 		return Destructive
 	case ClassKeyRotation:
 		return Destructive
-	case ClassAgentUpdate, ClassOSDockerStep, ClassOSPVEStep, ClassAgentConfigUpdate:
+	case ClassAgentUpdate, ClassOSDockerStep, ClassOSPVEStep, ClassOSKernelStep, ClassAgentConfigUpdate, ClassAddInternalPlace:
 		// Never benign — no agent-internal provenance can make replacing the agent binary
 		// unsigned-safe (a compromised process must not be able to self-bless an update).
 		return Destructive

internal/signedjobs/internalplace.go

@@ -0,0 +1,91 @@
+package signedjobs
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/localapi"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// opAddInternalPlace is the op class this executor serves (mirrors reconcile.ClassAddInternalPlace).
+const opAddInternalPlace = "add_internal_place"
+
+// InternalPlaceHelper is the root helper's path (configs/felhom-internal-place, from the config bundle).
+const InternalPlaceHelper = "/usr/local/sbin/felhom-internal-place"
+
+var reHelperResult = regexp.MustCompile(`^(created|existing|formatted) uuid=([0-9a-fA-F-]{36}) gib=([0-9]+)$`)
+
+// InternalPlaceExecutor adds the internal data place to an OLD one-disk box (felhom.eu architecture/16 §9: „one-disk
+// boxes get no internal place by themselves; adding one later is a signed operator job, not a household button").
+// It runs the SAME root helper the installer runs — `felhom-internal-place create 0` (0 GiB planned: the guest's
+// volumes already exist and are counted) — writes the record the agent mounts from, and asks the local API to mount
+// it now. Every safety rule (the ruled size, never format what holds anything) lives in the helper, as root.
+//
+// The op carries no parameters: the size is the rule's, never the signer's. Destructive-class by default (the
+// classifier's fail-safe; ClassAddInternalPlace documents it): it takes thin space on the system disk, so only an
+// operator signature may start it.
+type InternalPlaceExecutor struct {
+	runner     proxmox.Runner
+	recordFile string
+	ensure     func(context.Context) // late-bound: the local API server is built after the jobs runner
+	logger     *slog.Logger
+}
+
+// NewInternalPlaceExecutor wires the executor. ensure may be nil at construction and set later through SetEnsure.
+func NewInternalPlaceExecutor(runner proxmox.Runner, recordFile string, logger *slog.Logger) *InternalPlaceExecutor {
+	if logger == nil {
+		logger = slog.Default()
+	}
+	return &InternalPlaceExecutor{runner: runner, recordFile: recordFile, logger: logger}
+}
+
+// SetEnsure late-binds the mount step (localapi.Server.EnsureInternalPlace).
+func (e *InternalPlaceExecutor) SetEnsure(f func(context.Context)) { e.ensure = f }
+
+// Execute implements signedjobs.Executor for add_internal_place.
+func (e *InternalPlaceExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
+	if op != opAddInternalPlace {
+		return ErrNoExecutor
+	}
+	if p := bytes.TrimSpace(params); len(p) > 0 && !bytes.Equal(p, []byte("{}")) && !bytes.Equal(p, []byte("null")) {
+		return fmt.Errorf("add_internal_place: takes no parameters (the size is the ruled rule's), got %s", p)
+	}
+	if e.runner == nil || e.recordFile == "" {
+		return fmt.Errorf("add_internal_place: not wired on this host (no privileged runner or state dir)")
+	}
+	start := time.Now()
+	e.logger.Warn("add_internal_place: executing operator-signed job (the internal data place, `16` §9)")
+	out, stderr, err := e.runner.Run(ctx, InternalPlaceHelper, "create", "0")
+	line := strings.TrimSpace(string(out))
+	if err != nil {
+		return fmt.Errorf("add_internal_place: helper refused: %v: %s", err, strings.TrimSpace(string(stderr)))
+	}
+	if strings.HasPrefix(line, "skipped ") {
+		// Not an error the operator can retry away: the pool has no room by the ruled rule. Fail the job with the
+		// helper's own numbers so the hub shows why.
+		return fmt.Errorf("add_internal_place: %s", line)
+	}
+	m := reHelperResult.FindStringSubmatch(line)
+	if m == nil {
+		return fmt.Errorf("add_internal_place: unexpected helper output %q", line)
+	}
+	gib, _ := strconv.Atoi(m[3])
+	rec := localapi.InternalPlaceRecord{FSUUID: m[2], GiB: gib, MadeBy: "signed-job", MadeAt: time.Now().UTC().Format(time.RFC3339)}
+	if err := localapi.WriteInternalPlace(e.recordFile, rec); err != nil {
+		return fmt.Errorf("add_internal_place: writing the record: %w", err)
+	}
+	if e.ensure != nil {
+		e.ensure(ctx)
+	}
+	e.logger.Warn("add_internal_place: complete", "result", m[1], "fs_uuid", m[2], "gib", gib,
+		"duration_ms", time.Since(start).Milliseconds())
+	return nil
+}

internal/signedjobs/internalplace_test.go

@@ -0,0 +1,94 @@
+package signedjobs
+
+import (
+	"context"
+	"errors"
+	"io"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/localapi"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
+)
+
+// add_internal_place (felhom.eu architecture/16 §9, agent v0.158.0): the operator's job for an OLD one-disk box.
+
+type ipRunner struct {
+	out, stderr string
+	err         error
+	calls       [][]string
+}
+
+func (r *ipRunner) Run(_ context.Context, name string, args ...string) ([]byte, []byte, error) {
+	r.calls = append(r.calls, append([]string{name}, args...))
+	return []byte(r.out), []byte(r.stderr), r.err
+}
+func (r *ipRunner) RunStdin(ctx context.Context, _ io.Reader, name string, args ...string) ([]byte, []byte, error) {
+	return r.Run(ctx, name, args...)
+}
+
+func ipExec(t *testing.T, r *ipRunner) (*InternalPlaceExecutor, string, *int) {
+	t.Helper()
+	file := filepath.Join(t.TempDir(), localapi.InternalPlaceFile)
+	e := NewInternalPlaceExecutor(r, file, slog.New(slog.NewTextHandler(io.Discard, nil)))
+	n := 0
+	e.SetEnsure(func(context.Context) { n++ })
+	return e, file, &n
+}
+
+func TestAddInternalPlace_RunsTheHelperWritesTheRecordAndMounts(t *testing.T) {
+	r := &ipRunner{out: "created uuid=0b6e4c5a-1d2e-4f3a-9b8c-7d6e5f4a3b2c gib=33\n"}
+	e, file, ensured := ipExec(t, r)
+	if err := e.Execute(context.Background(), "add_internal_place", []byte(`{}`)); err != nil {
+		t.Fatal(err)
+	}
+	if len(r.calls) != 1 || strings.Join(r.calls[0], " ") != InternalPlaceHelper+" create 0" {
+		t.Fatalf("the helper must be called exactly as `create 0`, got %v", r.calls)
+	}
+	rec, ok, err := localapi.ReadInternalPlace(file)
+	if err != nil || !ok || rec.FSUUID != "0b6e4c5a-1d2e-4f3a-9b8c-7d6e5f4a3b2c" || rec.GiB != 33 || rec.MadeBy != "signed-job" {
+		t.Fatalf("record: %+v ok=%v err=%v", rec, ok, err)
+	}
+	if *ensured != 1 {
+		t.Fatalf("the mount must be asked for once, got %d", *ensured)
+	}
+}
+
+func TestAddInternalPlace_NoRoomOrRefusalOrGarbage_WritesNothing(t *testing.T) {
+	for name, r := range map[string]*ipRunner{
+		"skipped": {out: "skipped only 7 GiB free for it (pool 53, reserve 16, promised 102, planned 0; needs 20)"},
+		"refused": {err: errors.New("exit status 1"), stderr: "felhom-internal-place: REFUSED: holds something"},
+		"garbage": {out: "created uuid=../../etc gib=1"},
+	} {
+		e, file, ensured := ipExec(t, r)
+		if err := e.Execute(context.Background(), "add_internal_place", nil); err == nil {
+			t.Fatalf("%s: want an error", name)
+		}
+		if _, statErr := os.Stat(file); !os.IsNotExist(statErr) || *ensured != 0 {
+			t.Fatalf("%s: no record and no mount may follow, stat=%v ensured=%d", name, statErr, *ensured)
+		}
+	}
+}
+
+func TestAddInternalPlace_TakesNoParametersAndIgnoresOtherOps(t *testing.T) {
+	r := &ipRunner{out: "created uuid=0b6e4c5a-1d2e-4f3a-9b8c-7d6e5f4a3b2c gib=33"}
+	e, _, _ := ipExec(t, r)
+	if err := e.Execute(context.Background(), "add_internal_place", []byte(`{"gib":900}`)); err == nil || len(r.calls) != 0 {
+		t.Fatalf("a size from the signer must be refused before the helper runs, err=%v calls=%v", err, r.calls)
+	}
+	if err := e.Execute(context.Background(), "decommission", []byte(`{}`)); !errors.Is(err, ErrNoExecutor) {
+		t.Fatalf("another op: want ErrNoExecutor, got %v", err)
+	}
+}
+
+func TestAddInternalPlace_IsSignatureOnly(t *testing.T) {
+	if got := reconcile.Classify(reconcile.ClassAddInternalPlace, reconcile.Provenance{}); got != reconcile.Destructive {
+		t.Fatalf("add_internal_place must need an operator signature, classified %v", got)
+	}
+	if string(reconcile.ClassAddInternalPlace) != opAddInternalPlace {
+		t.Fatalf("op string drift: %q vs %q", reconcile.ClassAddInternalPlace, opAddInternalPlace)
+	}
+}

internal/storage/candidates.go

@@ -13,14 +13,16 @@ import (
 // (guarded, Impl-1) and/or mounts + binds. Blank disks are "initialize"-only; disks already carrying a
 // mountable FS are ALSO "attach" candidates.
 type CandidateDisk struct {
-	Device      string `json:"device"`       // whole disk, e.g. /dev/sdd
-	SizeBytes   int64  `json:"size_bytes"`   // 0 when unreadable
+	Device      string `json:"device"`     // whole disk, e.g. /dev/sdd
+	SizeBytes   int64  `json:"size_bytes"` // 0 when unreadable
 	Model       string `json:"model,omitempty"`
-	FSType      string `json:"fstype,omitempty"`      // first filesystem found ("" = blank)
-	DataBearing bool   `json:"data_bearing"`          // has any FS / partition (→ wipe-confirm downstream)
-	Mountable   bool   `json:"mountable"`             // carries an ext4/xfs FS the agent can mount as-is
+	FSType      string `json:"fstype,omitempty"`       // first filesystem found ("" = blank)
+	DataBearing bool   `json:"data_bearing"`           // has any FS / partition (→ wipe-confirm downstream)
+	Mountable   bool   `json:"mountable"`              // carries an ext4/xfs FS the agent can mount as-is
 	MountSource string `json:"mount_source,omitempty"` // the node to mount for attach (e.g. /dev/sdd1)
 	DurableID   string `json:"durable_id,omitempty"`   // "uuid:<fs-uuid>" if it has an FS; "" for a blank disk
+	// Partitions (v0.158.0, felhom.eu `16` §6): each partition of this disk as its own place — see partitions.go.
+	Partitions []CandidatePartition `json:"partitions,omitempty"`
 }
 
 // mountableFSTypes are the filesystems the agent can mount as-is (EnsureMount) → an "attach" candidate.
@@ -83,6 +85,8 @@ func (h *SudoHostOps) buildCandidate(dev, name string) CandidateDisk {
 			if len(nodes) > 1 {
 				c.DataBearing = true
 			}
+			c.Partitions = candidatePartitions(lout, name, readSysPartSize, readSysPartNumber, h.host.ResolveUUID,
+				felhomOwnedMounts(dev, nodes, h.mountTable))
 		}
 	}
 	return c

internal/storage/durable_device.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 )
@@ -24,8 +25,13 @@ var devDiskRoot = "/dev/disk"
 const (
 	durableByID   = "byid:"
 	durableByUUID = "byuuid:"
+	// partFSUUIDSep joins a partition's by-id link and its fs-UUID in one wipe id (v0.158.0, `16` §6).
+	partFSUUIDSep = "+fsuuid:"
 )
 
+// rePartLink matches a by-id link of a PARTITION (udev appends -part<N> to the disk's link).
+var rePartLink = regexp.MustCompile(`-part[1-9][0-9]{0,2}$`)
+
 // byIDPriority ranks /dev/disk/by-id link prefixes most-stable-first: wwn (hardware world-wide
 // name) > nvme-eui (NVMe EUI) > nvme-/ata-/scsi-/usb- (model+serial). dm-/lvm-/md- names are
 // excluded (they are mapper constructs, not the physical disk we want to bind a wipe to).
@@ -41,6 +47,14 @@ func DeviceDurableID(device string) (string, error) {
 	}
 	// 1. best by-id link pointing at this device.
 	if name := bestByIDLink(target); name != "" {
+		// v0.158.0 (felhom.eu `16` §6): a PARTITION's link already carries the disk id + the part number
+		// (wwn-…-part2). When the part holds a filesystem, its fs-UUID is bound too, so a part that was reformatted —
+		// or another disk's part2 that took the link — derives a different id and the wipe refuses.
+		if rePartLink.MatchString(name) {
+			if uuid := byUUIDFor(target); uuid != "" {
+				return durableByID + name + partFSUUIDSep + uuid, nil
+			}
+		}
 		return durableByID + name, nil
 	}
 	// 2. fallback: a filesystem UUID symlink.
@@ -56,10 +70,29 @@ func ResolveDurableDevice(durableID string) (string, error) {
 	switch {
 	case strings.HasPrefix(durableID, durableByID):
 		name := strings.TrimPrefix(durableID, durableByID)
+		fsUUID := ""
+		if i := strings.Index(name, partFSUUIDSep); i >= 0 {
+			name, fsUUID = name[:i], name[i+len(partFSUUIDSep):]
+			if !rePartLink.MatchString(name) || !safeLinkName(fsUUID) {
+				return "", fmt.Errorf("storage: unsafe durable id %q", durableID)
+			}
+		}
 		if !safeLinkName(name) {
 			return "", fmt.Errorf("storage: unsafe durable id %q", durableID)
 		}
-		return filepath.EvalSymlinks(filepath.Join(devDiskRoot, "by-id", name))
+		dev, err := filepath.EvalSymlinks(filepath.Join(devDiskRoot, "by-id", name))
+		if err != nil || fsUUID == "" {
+			return dev, err
+		}
+		// Both halves must name the SAME device now (`16` §6): the part by its disk id + number, and its filesystem.
+		byFS, ferr := filepath.EvalSymlinks(filepath.Join(devDiskRoot, "by-uuid", fsUUID))
+		if ferr != nil {
+			return "", fmt.Errorf("storage: durable id %q: its filesystem %s no longer resolves: %w", durableID, fsUUID, ferr)
+		}
+		if byFS != dev {
+			return "", fmt.Errorf("storage: durable id %q: the part (%s) and its filesystem (%s) are different devices now", durableID, dev, byFS)
+		}
+		return dev, nil
 	case strings.HasPrefix(durableID, durableByUUID):
 		uuid := strings.TrimPrefix(durableID, durableByUUID)
 		if !safeLinkName(uuid) {

internal/storage/identity.go

@@ -0,0 +1,445 @@
+package storage
+
+import (
+	"bufio"
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Physical-disk identity of a storage place — felhom.eu architecture/16-storage-physical-identity.md §3.
+//
+// A storage place (a PVE storage, an enrolled drive, the guest's data volume, a network share) is
+// reduced to the PHYSICAL whole disks under it — partition → parent disk, device-mapper / LVM thin →
+// sysfs slaves (recursive), loop → its backing file → the filesystem holding that file — and each disk
+// is named by a key the agent trusts: `eui:` for NVMe, `serial:<bus>:<model>:<serial>` from udev,
+// `wwn:` only when no serial exists and the WWN carries a vendor (OUI ≠ 000000).
+//
+// The verdict is AGENT-COMPUTED evidence (`16` §10): it is read from /sys, /run/udev/data and
+// /proc/mounts only, never from a caller's claim, so a compromised controller cannot make two places
+// "different disks". `proven` means every disk under the place has a key the agent trusts; anything
+// else is `unknown` with ONE reason, chosen by precedence (vm > network > usb_bridge > weak_wwn >
+// no_serial). Nothing is cached: every call reads the current topology, so a disk swapped in the same
+// bay is re-judged on the next read (the "right before each Tier-2 run" rule is the caller calling).
+//
+// Pinned by identity_test.go (fixture /sys + udev trees, one per §3 case) — the spike that proved the
+// walk on real devices: felhom.eu documentation/audits/storage-identity-2026-10-15/.
+
+const (
+	IdentityProven  = "proven"
+	IdentityUnknown = "unknown"
+
+	ReasonVM        = "vm"
+	ReasonNetwork   = "network"
+	ReasonUSBBridge = "usb_bridge"
+	ReasonWeakWWN   = "weak_wwn"
+	ReasonNoSerial  = "no_serial"
+
+	PlaceKindSystem    = "system"
+	PlaceKindInternal  = "internal"
+	PlaceKindDisk      = "disk"
+	PlaceKindPartition = "partition"
+	PlaceKindNetwork   = "network"
+)
+
+// reasonRank orders the unknown reasons: the first one a place hits, by this precedence, is reported.
+var reasonRank = map[string]int{ReasonVM: 0, ReasonNetwork: 1, ReasonUSBBridge: 2, ReasonWeakWWN: 3, ReasonNoSerial: 4}
+
+// PlaceIdentity is what a storage place reports.
+type PlaceIdentity struct {
+	PhysicalDisks []string // disk keys, sorted, deduplicated
+	Identity      string   // proven | unknown | "" (not computed — e.g. the device is absent)
+	Reason        string   // set only when Identity == unknown
+}
+
+// Computed reports whether a verdict was reached at all.
+func (p PlaceIdentity) Computed() bool { return p.Identity != "" }
+
+// IdentityHost is the read surface the resolver needs. SysfsIdentityHost is production; tests use the
+// same struct pointed at fixture trees.
+type IdentityHost interface {
+	Mounts() ([]Mount, error)
+	// KernelName maps a /dev path (symlinks allowed: /dev/mapper/x, /dev/pve/y) to its kernel block name.
+	KernelName(dev string) (string, bool)
+	// Parent returns the parent disk's kernel name when name is a partition.
+	Parent(name string) (string, bool)
+	// Slaves lists /sys/class/block/<name>/slaves.
+	Slaves(name string) []string
+	// LoopBackingFile returns a loop device's backing file.
+	LoopBackingFile(name string) (string, bool)
+	// UdevProps returns the udev E: properties of a block device.
+	UdevProps(name string) map[string]string
+	// Virt returns the VM technology ("none" on bare metal).
+	Virt() string
+}
+
+// SysfsIdentityHost reads the real host. Every path is a field so tests can point it at fixtures.
+type SysfsIdentityHost struct {
+	SysClass   string                       // default /sys/class/block
+	UdevData   string                       // default /run/udev/data
+	ProcMounts string                       // default /proc/mounts
+	DevResolve func(string) (string, error) // default filepath.EvalSymlinks
+	VirtFn     func() string                // default `systemd-detect-virt --vm`, read once
+
+	virtOnce sync.Once
+	virt     string
+}
+
+// NewSysfsIdentityHost returns the production reader.
+func NewSysfsIdentityHost() *SysfsIdentityHost { return &SysfsIdentityHost{} }
+
+func (h *SysfsIdentityHost) sysClass() string {
+	if h.SysClass != "" {
+		return h.SysClass
+	}
+	return "/sys/class/block"
+}
+
+func (h *SysfsIdentityHost) Mounts() ([]Mount, error) {
+	return (&ProcHostReader{ProcMounts: h.ProcMounts}).Mounts()
+}
+
+func (h *SysfsIdentityHost) KernelName(dev string) (string, bool) {
+	if !strings.HasPrefix(dev, "/dev/") {
+		return "", false
+	}
+	resolve := h.DevResolve
+	if resolve == nil {
+		resolve = filepath.EvalSymlinks
+	}
+	real := dev
+	if r, err := resolve(dev); err == nil {
+		real = r
+	}
+	name := filepath.Base(real)
+	if _, err := os.Stat(filepath.Join(h.sysClass(), name)); err != nil {
+		return "", false
+	}
+	return name, true
+}
+
+func (h *SysfsIdentityHost) Parent(name string) (string, bool) {
+	p := filepath.Join(h.sysClass(), name)
+	if _, err := os.Stat(filepath.Join(p, "partition")); err != nil {
+		return "", false
+	}
+	real, err := filepath.EvalSymlinks(p)
+	if err != nil {
+		return "", false
+	}
+	return filepath.Base(filepath.Dir(real)), true
+}
+
+func (h *SysfsIdentityHost) Slaves(name string) []string {
+	entries, err := os.ReadDir(filepath.Join(h.sysClass(), name, "slaves"))
+	if err != nil {
+		return nil
+	}
+	out := make([]string, 0, len(entries))
+	for _, e := range entries {
+		out = append(out, e.Name())
+	}
+	sort.Strings(out)
+	return out
+}
+
+func (h *SysfsIdentityHost) LoopBackingFile(name string) (string, bool) {
+	if !strings.HasPrefix(name, "loop") {
+		return "", false
+	}
+	b, err := os.ReadFile(filepath.Join(h.sysClass(), name, "loop", "backing_file"))
+	if err != nil {
+		return "", false
+	}
+	f := strings.TrimSpace(string(b))
+	return f, f != ""
+}
+
+func (h *SysfsIdentityHost) UdevProps(name string) map[string]string {
+	out := map[string]string{}
+	devB, err := os.ReadFile(filepath.Join(h.sysClass(), name, "dev"))
+	if err != nil {
+		return out
+	}
+	dir := h.UdevData
+	if dir == "" {
+		dir = "/run/udev/data"
+	}
+	f, err := os.Open(filepath.Join(dir, "b"+strings.TrimSpace(string(devB))))
+	if err != nil {
+		return out
+	}
+	defer f.Close()
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		line := sc.Text()
+		if !strings.HasPrefix(line, "E:") {
+			continue
+		}
+		k, v, ok := strings.Cut(line[2:], "=")
+		if ok {
+			out[k] = v
+		}
+	}
+	return out
+}
+
+func (h *SysfsIdentityHost) Virt() string {
+	h.virtOnce.Do(func() {
+		if h.VirtFn != nil {
+			h.virt = h.VirtFn()
+			return
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		// --vm: a container is not a reason (the agent runs on the host); exit 1 + "none" on metal.
+		out, _ := exec.CommandContext(ctx, "systemd-detect-virt", "--vm").Output()
+		h.virt = strings.TrimSpace(string(out))
+		if h.virt == "" {
+			h.virt = "unknown"
+		}
+	})
+	return h.virt
+}
+
+// IdentityResolver turns devices and host paths into PlaceIdentity.
+type IdentityResolver struct {
+	Host IdentityHost
+}
+
+// NewIdentityResolver returns a resolver over the real host.
+func NewIdentityResolver() *IdentityResolver {
+	return &IdentityResolver{Host: NewSysfsIdentityHost()}
+}
+
+var networkFSTypes = map[string]bool{
+	"nfs": true, "nfs4": true, "cifs": true, "smb3": true, "fuse.sshfs": true, "9p": true, "autofs": true, "ceph": true, "glusterfs": true,
+}
+
+// NetworkPlace is the fixed verdict for a network share or a remote store.
+func NetworkPlace() PlaceIdentity {
+	return PlaceIdentity{PhysicalDisks: []string{}, Identity: IdentityUnknown, Reason: ReasonNetwork}
+}
+
+// MountFor returns the mount that holds path (longest mountpoint prefix; the LAST entry wins on an equal
+// mountpoint, which is the one stacked on top — an automount's real filesystem over its autofs trigger).
+func MountFor(mounts []Mount, path string) (Mount, bool) {
+	p := filepath.Clean(path)
+	var best Mount
+	found := false
+	for _, m := range mounts {
+		mp := filepath.Clean(m.MountPoint)
+		if p != mp && !strings.HasPrefix(p, strings.TrimSuffix(mp, "/")+"/") {
+			continue
+		}
+		if !found || len(mp) >= len(filepath.Clean(best.MountPoint)) {
+			best, found = m, true
+		}
+	}
+	return best, found
+}
+
+// HostPath resolves the filesystem holding a HOST path.
+func (r *IdentityResolver) HostPath(path string) PlaceIdentity {
+	return r.hostPath(path, 0)
+}
+
+func (r *IdentityResolver) hostPath(path string, depth int) PlaceIdentity {
+	if r == nil || r.Host == nil || depth > 4 {
+		return PlaceIdentity{}
+	}
+	mounts, err := r.Host.Mounts()
+	if err != nil {
+		return PlaceIdentity{}
+	}
+	m, ok := MountFor(mounts, path)
+	if !ok {
+		return PlaceIdentity{}
+	}
+	if networkFSTypes[m.FSType] || !strings.HasPrefix(m.Device, "/dev/") {
+		return NetworkPlace()
+	}
+	return r.device(m.Device, depth)
+}
+
+// Device resolves a block device (a /dev path, symlinks allowed).
+func (r *IdentityResolver) Device(dev string) PlaceIdentity {
+	return r.device(dev, 0)
+}
+
+func (r *IdentityResolver) device(dev string, depth int) PlaceIdentity {
+	if r == nil || r.Host == nil || dev == "" {
+		return PlaceIdentity{}
+	}
+	name, ok := r.Host.KernelName(dev)
+	if !ok {
+		return PlaceIdentity{}
+	}
+	keys := map[string]bool{}
+	reason := ""
+	if !r.walk(name, depth, map[string]bool{}, keys, &reason) {
+		return PlaceIdentity{}
+	}
+	out := PlaceIdentity{PhysicalDisks: sortedKeys(keys), Identity: IdentityProven}
+	if reason != "" {
+		out.Identity, out.Reason = IdentityUnknown, reason
+	}
+	return out
+}
+
+// walk adds the keys of every physical disk under name; ok=false when a branch cannot be grounded.
+func (r *IdentityResolver) walk(name string, depth int, seen, keys map[string]bool, reason *string) bool {
+	if seen[name] {
+		return true // a diamond (a thin pool's tmeta and tdata on one partition): already counted
+	}
+	if len(seen) > 64 {
+		return false
+	}
+	seen[name] = true
+	if parent, ok := r.Host.Parent(name); ok {
+		return r.walk(parent, depth, seen, keys, reason)
+	}
+	if file, ok := r.Host.LoopBackingFile(name); ok {
+		p := r.hostPath(file, depth+1)
+		if !p.Computed() {
+			return false
+		}
+		for _, k := range p.PhysicalDisks {
+			keys[k] = true
+		}
+		noteReason(reason, p.Reason)
+		return true
+	}
+	if slaves := r.Host.Slaves(name); len(slaves) > 0 {
+		for _, s := range slaves {
+			if !r.walk(s, depth, seen, keys, reason) {
+				return false
+			}
+		}
+		return true
+	}
+	if strings.HasPrefix(name, "dm-") || strings.HasPrefix(name, "md") || strings.HasPrefix(name, "loop") {
+		return false // a virtual device with nothing beneath it cannot be grounded
+	}
+	key, why := r.diskKey(name)
+	keys[key] = true
+	noteReason(reason, why)
+	return true
+}
+
+func noteReason(cur *string, why string) {
+	if why == "" {
+		return
+	}
+	if *cur == "" || reasonRank[why] < reasonRank[*cur] {
+		*cur = why
+	}
+}
+
+// diskKey names one whole disk and says why it is not trusted ("" when it is).
+func (r *IdentityResolver) diskKey(name string) (key, reason string) {
+	p := r.Host.UdevProps(name)
+	serial := strings.TrimSpace(p["ID_SERIAL_SHORT"])
+	model := strings.TrimSpace(p["ID_MODEL"])
+	bus := strings.TrimSpace(p["ID_BUS"])
+	wwn := strings.ToLower(strings.TrimSpace(p["ID_WWN"]))
+	if bus == "" && strings.HasPrefix(name, "nvme") {
+		bus = "nvme"
+	}
+	usb := bus == "usb" || strings.Contains(p["DEVPATH"], "/usb")
+	switch {
+	case strings.HasPrefix(name, "nvme") && (strings.HasPrefix(wwn, "eui.") || strings.HasPrefix(wwn, "nvme.")):
+		key = "eui:" + strings.TrimPrefix(strings.TrimPrefix(wwn, "eui."), "nvme.")
+	case serial != "":
+		key = "serial:" + bus + ":" + model + ":" + serial
+		if usb && FakeBridgeSerial(serial) {
+			reason = ReasonUSBBridge
+		}
+	case wwn != "" && WWNHasVendor(wwn):
+		key = "wwn:" + wwn
+	case wwn != "":
+		key, reason = "wwn:"+wwn, ReasonWeakWWN
+	default:
+		key, reason = "dev:"+name, ReasonNoSerial
+	}
+	if v := r.Host.Virt(); v != "none" {
+		reason = ReasonVM // inside a VM a virtual disk says nothing about the host disk (spike cases 5–6)
+	}
+	return key, reason
+}
+
+// WWNHasVendor reports whether an NAA-5/6 WWN carries a registered vendor (OUI ≠ 000000). Other NAA
+// formats are taken as they are. Measured: the N100's AirDisk SSD reports 0x5000000123456f1f.
+func WWNHasVendor(wwn string) bool {
+	h := strings.TrimPrefix(strings.ToLower(wwn), "0x")
+	if len(h) < 7 {
+		return false
+	}
+	if h[0] == '5' || h[0] == '6' {
+		return h[1:7] != "000000"
+	}
+	return true
+}
+
+// FakeBridgeSerial reports a serial that a USB bridge reports for any disk: too short, one repeated
+// character, or a known placeholder. UNPROVEN on a real enclosure (R-1077) — the rule is the design's.
+func FakeBridgeSerial(s string) bool {
+	s = strings.ToUpper(strings.TrimSpace(s))
+	if len(s) < 6 {
+		return true
+	}
+	if strings.Count(s, s[:1]) == len(s) {
+		return true
+	}
+	switch s {
+	case "123456789", "1234567890", "123456789ABC", "0123456789ABCDEF", "1234567890ABCDEF", "DEADBEEF":
+		return true
+	}
+	return false
+}
+
+func sortedKeys(m map[string]bool) []string {
+	out := make([]string, 0, len(m))
+	for k := range m {
+		out = append(out, k)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// Relation compares two places (`16` §4). A SHARED disk key is a positive fact, so two places on one disk
+// are "same, proven" even when that disk is unknown (inside a VM, two parts of one virtual disk). Otherwise
+// proven is true only when both verdicts are proven; different then means "no disk in common". When proven
+// is false, different only says the known keys do not overlap — callers must act on proven first.
+// reason: "" (proven, different), "same_disk", "unmapped" (a side has no verdict), or the unknown reason.
+func Relation(a, b PlaceIdentity) (different, proven bool, reason string) {
+	if !a.Computed() || !b.Computed() {
+		return false, false, "unmapped"
+	}
+	set := map[string]bool{}
+	for _, k := range a.PhysicalDisks {
+		set[k] = true
+	}
+	shared := false
+	for _, k := range b.PhysicalDisks {
+		if set[k] {
+			shared = true
+		}
+	}
+	if shared {
+		return false, true, "same_disk"
+	}
+	if a.Identity == IdentityProven && b.Identity == IdentityProven {
+		return true, true, ""
+	}
+	why := a.Reason
+	if why == "" || (b.Reason != "" && reasonRank[b.Reason] < reasonRank[why]) {
+		why = b.Reason
+	}
+	return true, false, why
+}

internal/storage/identity_test.go

@@ -0,0 +1,257 @@
+package storage
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// Fixture /sys/class/block + /run/udev/data + /proc/mounts trees, one per `16` §3 case. The tree mimics the
+// kernel: /sys/devices/.../<disk>/<part> real dirs (a partition carries a "partition" file), /sys/class/block
+// symlinks, a "dev" file per node, udev "E:" lines keyed by major:minor. The cases are the ones the spike
+// measured on real devices (felhom.eu documentation/audits/storage-identity-2026-10-15/).
+
+type fx struct {
+	t      *testing.T
+	root   string
+	minor  int
+	mounts []string
+	links  map[string]string // /dev path -> kernel name
+	virt   string
+}
+
+func newFx(t *testing.T) *fx {
+	t.Helper()
+	r := t.TempDir()
+	for _, d := range []string{"sys/class/block", "sys/devices", "udev"} {
+		if err := os.MkdirAll(filepath.Join(r, d), 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return &fx{t: t, root: r, links: map[string]string{}, virt: "none"}
+}
+
+func (f *fx) write(p, s string) {
+	f.t.Helper()
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		f.t.Fatal(err)
+	}
+	if err := os.WriteFile(p, []byte(s), 0o644); err != nil {
+		f.t.Fatal(err)
+	}
+}
+
+// node makes a block node. parent "" → a top-level device. udev lines are "KEY=VAL".
+func (f *fx) node(name, parent string, udev ...string) {
+	f.t.Helper()
+	real := filepath.Join(f.root, "sys/devices", name)
+	if parent != "" {
+		pr, _ := filepath.EvalSymlinks(filepath.Join(f.root, "sys/class/block", parent))
+		real = filepath.Join(pr, name)
+		f.write(filepath.Join(real, "partition"), "1\n")
+	}
+	f.minor++
+	dev := "8:" + strconv.Itoa(f.minor)
+	f.write(filepath.Join(real, "dev"), dev+"\n")
+	if err := os.Symlink(real, filepath.Join(f.root, "sys/class/block", name)); err != nil {
+		f.t.Fatal(err)
+	}
+	var b strings.Builder
+	for _, u := range udev {
+		b.WriteString("E:" + u + "\n")
+	}
+	f.write(filepath.Join(f.root, "udev", "b"+dev), b.String())
+	f.links["/dev/"+name] = name
+}
+
+func (f *fx) slaves(name string, slaves ...string) {
+	f.t.Helper()
+	real, _ := filepath.EvalSymlinks(filepath.Join(f.root, "sys/class/block", name))
+	for _, s := range slaves {
+		if err := os.MkdirAll(filepath.Join(real, "slaves", s), 0o755); err != nil {
+			f.t.Fatal(err)
+		}
+	}
+}
+
+func (f *fx) loop(name, file string) {
+	real, _ := filepath.EvalSymlinks(filepath.Join(f.root, "sys/class/block", name))
+	f.write(filepath.Join(real, "loop", "backing_file"), file+"\n")
+}
+
+func (f *fx) mount(dev, mp, fstype string) {
+	f.mounts = append(f.mounts, dev+" "+mp+" "+fstype+" rw 0 0")
+}
+
+func (f *fx) resolver() *IdentityResolver {
+	f.write(filepath.Join(f.root, "mounts"), strings.Join(f.mounts, "\n")+"\n")
+	return &IdentityResolver{Host: &SysfsIdentityHost{
+		SysClass:   filepath.Join(f.root, "sys/class/block"),
+		UdevData:   filepath.Join(f.root, "udev"),
+		ProcMounts: filepath.Join(f.root, "mounts"),
+		DevResolve: func(p string) (string, error) {
+			if n, ok := f.links[p]; ok {
+				return "/dev/" + n, nil
+			}
+			return p, nil
+		},
+		VirtFn: func() string { return f.virt },
+	}}
+}
+
+var sanDisk = []string{"ID_BUS=ata", "ID_MODEL=SanDisk_X600", "ID_SERIAL_SHORT=182195804614", "ID_WWN=0x5001b448b60a9d6e"}
+
+// oneDiskLVM builds the PVE default layout on one SATA SSD: sda3 → pve-root, pve-data tmeta/tdata → tpool →
+// a guest volume (the shape of all three test boxes).
+func oneDiskLVM(f *fx) {
+	f.node("sda", "", sanDisk...)
+	f.node("sda3", "sda")
+	for _, d := range []string{"dm-1", "dm-2", "dm-3", "dm-4", "dm-6"} {
+		f.node(d, "")
+	}
+	f.slaves("dm-1", "sda3")
+	f.slaves("dm-2", "sda3")
+	f.slaves("dm-3", "sda3")
+	f.slaves("dm-4", "dm-2", "dm-3")
+	f.slaves("dm-6", "dm-4")
+	f.links["/dev/mapper/pve-root"] = "dm-1"
+	f.links["/dev/mapper/pve-data-tpool"] = "dm-4"
+	f.links["/dev/pve/vm-9201-disk-1"] = "dm-6"
+	f.mount("/dev/mapper/pve-root", "/", "ext4")
+}
+
+func TestIdentity_OneDiskLVM_AllPlacesSameProvenDisk(t *testing.T) {
+	f := newFx(t)
+	oneDiskLVM(f)
+	r := f.resolver()
+	want := []string{"serial:ata:SanDisk_X600:182195804614"}
+	for _, p := range []PlaceIdentity{r.HostPath("/var/lib/vz"), r.Device("/dev/mapper/pve-data-tpool"), r.Device("/dev/pve/vm-9201-disk-1")} {
+		if p.Identity != IdentityProven || !reflect.DeepEqual(p.PhysicalDisks, want) {
+			t.Fatalf("want proven %v, got %+v", want, p)
+		}
+	}
+	diff, proven, why := Relation(r.HostPath("/var/lib/vz"), r.Device("/dev/pve/vm-9201-disk-1"))
+	if diff || !proven || why != "same_disk" {
+		t.Fatalf("root vs guest volume: want same+proven, got diff=%v proven=%v why=%q", diff, proven, why)
+	}
+}
+
+func TestIdentity_TwoDisks_ProvenDifferent(t *testing.T) {
+	f := newFx(t)
+	oneDiskLVM(f)
+	f.node("sdb", "", "ID_BUS=ata", "ID_MODEL=TOSHIBA_MQ04ABF100", "ID_SERIAL_SHORT=65NOP3HDT", "ID_WWN=0x5000039ddb108568", "DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-3/block/sdb")
+	f.mount("/dev/sdb", "/mnt/hdd_1", "ext4")
+	f.mount("/dev/sdb", "/mnt/felhom-drives/hdd_1", "ext4") // the felhom-data bind shows the source device
+	r := f.resolver()
+	drive := r.HostPath("/mnt/felhom-drives/hdd_1/userdata")
+	if drive.Identity != IdentityProven || drive.PhysicalDisks[0] != "serial:ata:TOSHIBA_MQ04ABF100:65NOP3HDT" {
+		t.Fatalf("USB drive passing its identity: want proven, got %+v", drive)
+	}
+	diff, proven, why := Relation(r.Device("/dev/pve/vm-9201-disk-1"), drive)
+	if !diff || !proven || why != "" {
+		t.Fatalf("system vs drive: want different+proven, got %v %v %q", diff, proven, why)
+	}
+}
+
+func TestIdentity_TwoPartitionsOneDisk_Same(t *testing.T) {
+	f := newFx(t)
+	f.node("sdc", "", "ID_BUS=usb", "ID_MODEL=Portable", "ID_SERIAL_SHORT=NAAB7C21")
+	f.node("sdc1", "sdc")
+	f.node("sdc2", "sdc")
+	f.mount("/dev/sdc1", "/mnt/a", "ext4")
+	f.mount("/dev/sdc2", "/mnt/b", "ext4")
+	r := f.resolver()
+	diff, proven, why := Relation(r.HostPath("/mnt/a"), r.HostPath("/mnt/b"))
+	if diff || !proven || why != "same_disk" {
+		t.Fatalf("two partitions of one disk: want same+proven, got %v %v %q", diff, proven, why)
+	}
+}
+
+func TestIdentity_LoopPartitionsOnAFile_ResolveToTheFilesDisk(t *testing.T) {
+	f := newFx(t)
+	f.node("nvme0n1", "", "ID_MODEL=KXG50PNV1T02", "ID_SERIAL_SHORT=58BS11AFT8MQ", "ID_WWN=eui.000000000000001000080d020046c07b")
+	f.mount("/dev/nvme0n1", "/mnt/hdd_1", "ext4")
+	f.node("loop2", "")
+	f.loop("loop2", "/mnt/hdd_1/scratch.img")
+	f.node("loop2p1", "loop2") // the partition step must run BEFORE the loop step (the spike's probe bug)
+	f.mount("/dev/loop2p1", "/tmp/scrA", "ext4")
+	r := f.resolver()
+	p := r.HostPath("/tmp/scrA")
+	if p.Identity != IdentityProven || !reflect.DeepEqual(p.PhysicalDisks, []string{"eui:000000000000001000080d020046c07b"}) {
+		t.Fatalf("loop partition: want the NVMe's eui, got %+v", p)
+	}
+}
+
+func TestIdentity_WWNWithoutVendor(t *testing.T) {
+	f := newFx(t)
+	f.node("sda", "", "ID_BUS=ata", "ID_MODEL=AirDisk_512GB_SSD", "ID_SERIAL_SHORT=QDF922W009654S30EX", "ID_WWN=0x5000000123456f1f")
+	f.node("sdb", "", "ID_BUS=ata", "ID_MODEL=Cheap", "ID_WWN=0x5000000123456f1f")
+	r := f.resolver()
+	if p := r.Device("/dev/sda"); p.Identity != IdentityProven || p.PhysicalDisks[0] != "serial:ata:AirDisk_512GB_SSD:QDF922W009654S30EX" {
+		t.Fatalf("a real serial wins over a vendor-less WWN: got %+v", p)
+	}
+	if p := r.Device("/dev/sdb"); p.Identity != IdentityUnknown || p.Reason != ReasonWeakWWN {
+		t.Fatalf("no serial + vendor-less WWN: want unknown/weak_wwn, got %+v", p)
+	}
+}
+
+func TestIdentity_NoSerial(t *testing.T) {
+	f := newFx(t)
+	f.node("vdb", "", "ID_MODEL=")
+	if p := f.resolver().Device("/dev/vdb"); p.Identity != IdentityUnknown || p.Reason != ReasonNoSerial {
+		t.Fatalf("want unknown/no_serial, got %+v", p)
+	}
+}
+
+func TestIdentity_InsideAVM_EverythingUnknown(t *testing.T) {
+	f := newFx(t)
+	oneDiskLVM(f)
+	f.virt = "kvm"
+	f.node("sdb", "", "ID_BUS=scsi", "ID_MODEL=QEMU_HARDDISK", "ID_SERIAL_SHORT=drive-scsi1")
+	f.mount("/dev/sdb", "/mnt/felhom-drives/adatlemez", "ext4")
+	r := f.resolver()
+	a, b := r.Device("/dev/pve/vm-9201-disk-1"), r.HostPath("/mnt/felhom-drives/adatlemez")
+	for _, p := range []PlaceIdentity{a, b} {
+		if p.Identity != IdentityUnknown || p.Reason != ReasonVM {
+			t.Fatalf("inside a VM: want unknown/vm, got %+v", p)
+		}
+	}
+	diff, proven, why := Relation(a, b)
+	if proven || why != ReasonVM || !diff {
+		t.Fatalf("two virtual disks: want not proven (vm), got %v %v %q", diff, proven, why)
+	}
+}
+
+func TestIdentity_USBBridgeSerial(t *testing.T) {
+	f := newFx(t)
+	f.node("sdd", "", "ID_BUS=usb", "ID_MODEL=External_USB3.0", "ID_SERIAL_SHORT=000000000000")
+	f.node("sde", "", "ID_BUS=usb", "ID_MODEL=External_USB3.0", "ID_SERIAL_SHORT=20231106A1B2")
+	r := f.resolver()
+	if p := r.Device("/dev/sdd"); p.Identity != IdentityUnknown || p.Reason != ReasonUSBBridge {
+		t.Fatalf("a bridge placeholder serial: want unknown/usb_bridge, got %+v", p)
+	}
+	if p := r.Device("/dev/sde"); p.Identity != IdentityProven {
+		t.Fatalf("a USB disk with a plausible serial: want proven, got %+v", p)
+	}
+}
+
+func TestIdentity_NetworkShareAndUnmapped(t *testing.T) {
+	f := newFx(t)
+	oneDiskLVM(f)
+	f.mount("//192.168.0.123/TesztFilmek", "/mnt/felhom-drives/omv-filmek", "cifs")
+	r := f.resolver()
+	n := r.HostPath("/mnt/felhom-drives/omv-filmek/x")
+	if n.Identity != IdentityUnknown || n.Reason != ReasonNetwork || len(n.PhysicalDisks) != 0 {
+		t.Fatalf("network share: want unknown/network with no disks, got %+v", n)
+	}
+	_, proven, why := Relation(r.HostPath("/"), n)
+	if proven || why != ReasonNetwork {
+		t.Fatalf("system vs network: want not proven (network), got %v %q", proven, why)
+	}
+	if _, proven, why := Relation(PlaceIdentity{}, n); proven || why != "unmapped" {
+		t.Fatalf("an uncomputed side: want unmapped, got %v %q", proven, why)
+	}
+}

internal/storage/mkfs_guarded_suite_test.go

@@ -0,0 +1,24 @@
+package storage
+
+import (
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+// The root mkfs wrapper's own tests (configs/test_felhom_mkfs_guarded.py, agent v0.158.0 — a sibling partition that
+// is Felhom's own drive no longer blocks formatting the part next to it; every other mount still refuses) run with
+// the Go suite.
+func TestMkfsGuardedPythonSuite(t *testing.T) {
+	py, err := exec.LookPath("python3")
+	if err != nil {
+		t.Skip("python3 not found")
+	}
+	_, file, _, _ := runtime.Caller(0)
+	script := filepath.Join(filepath.Dir(file), "..", "..", "configs", "test_felhom_mkfs_guarded.py")
+	out, err := exec.Command(py, script).CombinedOutput()
+	if err != nil {
+		t.Fatalf("wrapper suite failed: %v\n%s", err, out)
+	}
+}

internal/storage/observe.go

@@ -40,6 +40,10 @@ type Observer struct {
 	// R-672 (v0.133.0): a thin pool crossing thinPoolAlarmFraction (data OR metadata) requests an
 	// out-of-band host report at once, so the hub's storage-fill alarm sees it in seconds instead of at
 	// the next 15-minute report. Rising edge per pool; re-armed below thinPoolRearmFraction.
+	// ident (agent v0.157.0, `16` §3) computes each target's physical-disk identity. nil → the fields stay
+	// empty (the pre-0.157 shape), which every consumer reads as "not computed".
+	ident *IdentityResolver
+
 	highMu     sync.Mutex
 	high       map[string]bool
 	onThinHigh func()
@@ -50,6 +54,51 @@ const (
 	thinPoolRearmFraction = 0.85
 )
 
+// SetIdentity wires the physical-disk identity resolver (main: NewIdentityResolver()).
+func (o *Observer) SetIdentity(r *IdentityResolver) { o.ident = r }
+
+// placeIdentity fills a target's identity fields (`16` §3). Network and remote stores are fixed
+// "unknown/network"; a dir storage is judged only on its OWN mount (the same rule as backing_device —
+// never the containing filesystem, so an absent drive is "not computed", never the root disk); the
+// builtin local and an lvmthin pool are the system disk(s) they sit on.
+func (o *Observer) placeIdentity(tgt *hub.StorageTarget, s proxmox.Storage) {
+	if o.ident == nil {
+		return
+	}
+	var p PlaceIdentity
+	switch tgt.Type {
+	case hub.StorageTypeNFS, hub.StorageTypeCIFS, hub.StorageTypePBS:
+		tgt.Kind = PlaceKindNetwork
+		p = NetworkPlace()
+	case hub.StorageTypeLocal:
+		tgt.Kind = PlaceKindSystem
+		if s.Path != "" {
+			p = o.ident.HostPath(s.Path)
+		}
+	case hub.StorageTypeLVMThin:
+		tgt.Kind = PlaceKindSystem
+		if s.VGName != "" && s.ThinPool != "" {
+			p = o.ident.Device("/dev/mapper/" + dmEscape(s.VGName) + "-" + dmEscape(s.ThinPool) + "-tpool")
+		}
+	default:
+		if tgt.BackingDevice == "" {
+			return // not its own mount (absent, or a dir on root): not computed
+		}
+		tgt.Kind = PlaceKindDisk
+		if _, known := wholeDiskOf(tgt.BackingDevice); known && !reWholeDisk.MatchString(tgt.BackingDevice) {
+			tgt.Kind = PlaceKindPartition
+		}
+		p = o.ident.Device(tgt.BackingDevice)
+	}
+	if !p.Computed() {
+		return
+	}
+	tgt.PhysicalDisks, tgt.Identity, tgt.IdentityReason = p.PhysicalDisks, p.Identity, p.Reason
+}
+
+// dmEscape doubles dashes the way device-mapper names an LV (pve + vm-1-disk-0 → pve-vm--1--disk--0).
+func dmEscape(s string) string { return strings.ReplaceAll(s, "-", "--") }
+
 // SetThinHighTrigger wires the out-of-band report request (main: the storage trigger channel).
 func (o *Observer) SetThinHighTrigger(f func()) { o.onThinHigh = f }
 
@@ -303,6 +352,9 @@ func (o *Observer) build(s proxmox.Storage, mounts []Mount) observed {
 		o.noteThinFill(s.Storage+"/data", frac)
 	}
 
+	// Physical-disk identity (`16` §3) — after typ/backing are settled; never from a caller's claim.
+	o.placeIdentity(&tgt, s)
+
 	// SMART-only device hint (v0.95.0): a dir-storage that lives INSIDE a shared filesystem (the
 	// builtin `local` on the LVM root) has empty backing by design, yet we can still read the PHYSICAL
 	// disk's SMART by resolving its containing filesystem. Gated to catDir + no own backing + reachable,

internal/storage/observe_identity_test.go

@@ -0,0 +1,73 @@
+package storage
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// The report rows carry the `16` §3 identity per storage type: local + lvmthin → the system disk; a dir
+// on its own partition → that disk, kind "partition"; nfs/pbs → network; an UNMOUNTED dir → not computed
+// (never the root disk — the same rule as backing_device).
+func TestObserve_FillsPhysicalDiskIdentity(t *testing.T) {
+	f := newFx(t)
+	oneDiskLVM(f)
+	f.node("sdb", "", "ID_BUS=ata", "ID_MODEL=TOSHIBA_MQ04ABF100", "ID_SERIAL_SHORT=65NOP3HDT")
+	f.node("sdb1", "sdb")
+	f.mount("/dev/sdb1", "/mnt/usb-backup", "ext4")
+	res := f.resolver()
+
+	api := &fakeStorageAPI{
+		node: "demo",
+		cluster: []proxmox.Storage{
+			{Storage: "local", Type: "dir", Path: "/var/lib/vz"},
+			{Storage: "local-lvm", Type: "lvmthin", VGName: "pve", ThinPool: "data"},
+			{Storage: "usb-backup", Type: "dir", Path: "/mnt/usb-backup"},
+			{Storage: "gone", Type: "dir", Path: "/mnt/gone"},
+			{Storage: "nfs-arch", Type: "nfs", Server: "10.0.0.5", Export: "/x"},
+		},
+		nodeSt: []proxmox.Storage{
+			{Storage: "local", Type: "dir", Path: "/var/lib/vz", Active: 1},
+			{Storage: "local-lvm", Type: "lvmthin", Active: 1},
+			{Storage: "usb-backup", Type: "dir", Path: "/mnt/usb-backup", Active: 1},
+			{Storage: "gone", Type: "dir", Path: "/mnt/gone", Active: 1},
+			{Storage: "nfs-arch", Type: "nfs", Active: 1},
+		},
+	}
+	host := &fakeHostReader{
+		mounts: []Mount{
+			{Device: "/dev/mapper/pve-root", MountPoint: "/", FSType: "ext4"},
+			{Device: "/dev/sdb1", MountPoint: "/mnt/usb-backup", FSType: "ext4"},
+		},
+		exists: map[string]bool{"/dev/sdb1": true, "/dev/mapper/pve-root": true},
+	}
+	ob := NewObserver(api, host, nil, quietLogger())
+	ob.SetIdentity(res)
+	got, err := ob.Observe(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	m := byName(got)
+	ssd := []string{"serial:ata:SanDisk_X600:182195804614"}
+	for _, n := range []string{"local", "local-lvm"} {
+		if tg := m[n]; tg.Kind != "system" || tg.Identity != "proven" || !reflect.DeepEqual(tg.PhysicalDisks, ssd) {
+			t.Errorf("%s: want system/proven on the SSD, got kind=%q id=%q disks=%v", n, tg.Kind, tg.Identity, tg.PhysicalDisks)
+		}
+	}
+	if tg := m["usb-backup"]; tg.Kind != "partition" || tg.Identity != "proven" || tg.PhysicalDisks[0] != "serial:ata:TOSHIBA_MQ04ABF100:65NOP3HDT" {
+		t.Errorf("usb-backup: got %+v", tg)
+	}
+	if tg := m["nfs-arch"]; tg.Kind != "network" || tg.IdentityReason != "network" {
+		t.Errorf("nfs: got kind=%q reason=%q", tg.Kind, tg.IdentityReason)
+	}
+	if tg := m["gone"]; tg.Identity != "" || len(tg.PhysicalDisks) != 0 {
+		t.Errorf("an unmounted dir must not be computed (never root's disk), got %+v", tg)
+	}
+	// Without a resolver the fields stay empty (the pre-0.157 shape).
+	plain, _ := NewObserver(api, host, nil, quietLogger()).Observe(context.Background())
+	if tg := byName(plain)["local"]; tg.Identity != "" || tg.Kind != "" {
+		t.Errorf("no resolver: want empty identity, got %+v", tg)
+	}
+}

internal/storage/partition_durable_test.go

@@ -0,0 +1,112 @@
+package storage
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+// The data-bearing partition path binds the disk id + the part number + the fs-UUID (felhom.eu architecture/16 §6,
+// agent v0.158.0). The wipe re-resolve (localapi antiRetargetResolveExpect) formats only when resolve(id) succeeds AND
+// DeviceDurableID(that device) == id — the round trip these tests pin, in the three ways a target can move.
+
+type partFixture struct{ base, root string }
+
+func newPartFixture(t *testing.T) partFixture {
+	t.Helper()
+	if runtime.GOOS == "windows" {
+		t.Skip("symlink fixtures run on Linux")
+	}
+	f := partFixture{base: t.TempDir()}
+	f.root = filepath.Join(f.base, "disk")
+	for _, d := range []string{"sdb", "sdb1", "sdb2", "sdc2"} {
+		if err := os.WriteFile(filepath.Join(f.base, d), []byte("x"), 0o600); err != nil {
+			t.Fatal(err)
+		}
+	}
+	os.MkdirAll(filepath.Join(f.root, "by-id"), 0o755)
+	os.MkdirAll(filepath.Join(f.root, "by-uuid"), 0o755)
+	withDevDiskRoot(t, f.root)
+	return f
+}
+
+func (f partFixture) link(t *testing.T, sub, name, dev string) {
+	t.Helper()
+	p := filepath.Join(f.root, sub, name)
+	os.Remove(p)
+	if err := os.Symlink(filepath.Join(f.base, dev), p); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (f partFixture) dev(name string) string { return filepath.Join(f.base, name) }
+
+func (f partFixture) standard(t *testing.T) {
+	f.link(t, "by-id", "wwn-0x5000aaaa", "sdb")
+	f.link(t, "by-id", "ata-TOSHIBA_MQ04_65NOP-part1", "sdb1")
+	f.link(t, "by-id", "wwn-0x5000aaaa-part1", "sdb1")
+	f.link(t, "by-id", "wwn-0x5000aaaa-part2", "sdb2")
+	f.link(t, "by-uuid", "1111-films", "sdb2")
+}
+
+func roundTrip(id string) (string, bool) {
+	dev, err := ResolveDurableDevice(id)
+	if err != nil {
+		return "", false
+	}
+	again, err := DeviceDurableID(dev)
+	return dev, err == nil && again == id
+}
+
+func TestPartitionWipeID_BindsDiskPartAndFilesystem(t *testing.T) {
+	f := newPartFixture(t)
+	f.standard(t)
+	id, err := DeviceDurableID(f.dev("sdb2"))
+	if err != nil || id != "byid:wwn-0x5000aaaa-part2+fsuuid:1111-films" {
+		t.Fatalf("a part with a filesystem: want disk id + part + fs-UUID, got %q %v", id, err)
+	}
+	if dev, ok := roundTrip(id); !ok || dev != f.dev("sdb2") {
+		t.Fatalf("the unchanged part must round-trip, got %q %v", dev, ok)
+	}
+	// A blank part (no filesystem) and a whole disk keep the plain by-id binding.
+	if id1, _ := DeviceDurableID(f.dev("sdb1")); id1 != "byid:wwn-0x5000aaaa-part1" {
+		t.Fatalf("a blank part: want the plain part link, got %q", id1)
+	}
+	if idDisk, _ := DeviceDurableID(f.dev("sdb")); idDisk != "byid:wwn-0x5000aaaa" {
+		t.Fatalf("a whole disk keeps today's id, got %q", idDisk)
+	}
+}
+
+func TestPartitionWipeID_ReformattedPartRefuses(t *testing.T) {
+	f := newPartFixture(t)
+	f.standard(t)
+	id, _ := DeviceDurableID(f.dev("sdb2"))
+	os.Remove(filepath.Join(f.root, "by-uuid", "1111-films"))
+	f.link(t, "by-uuid", "2222-other", "sdb2") // someone reformatted the part since the household confirmed
+	if _, ok := roundTrip(id); ok {
+		t.Fatalf("a reformatted part must not round-trip (the wipe would hit a different filesystem)")
+	}
+}
+
+func TestPartitionWipeID_LinkMovedToAnotherDiskRefuses(t *testing.T) {
+	f := newPartFixture(t)
+	f.standard(t)
+	id, _ := DeviceDurableID(f.dev("sdb2"))
+	f.link(t, "by-id", "wwn-0x5000aaaa-part2", "sdc2") // a different node took the part link; the fs is still sdb2
+	if _, err := ResolveDurableDevice(id); err == nil || !strings.Contains(err.Error(), "different devices") {
+		t.Fatalf("the part link and its filesystem on different devices must refuse, got %v", err)
+	}
+}
+
+func TestPartitionWipeID_RefusesAForgedCompound(t *testing.T) {
+	f := newPartFixture(t)
+	f.standard(t)
+	f.link(t, "by-uuid", "3333-whole", "sdb") // a filesystem straight on the whole disk: both halves name sdb
+	for _, id := range []string{"byid:wwn-0x5000aaaa+fsuuid:3333-whole", "byid:wwn-0x5000aaaa-part2+fsuuid:../x"} {
+		if _, err := ResolveDurableDevice(id); err == nil {
+			t.Fatalf("%q must be refused", id)
+		}
+	}
+}

internal/storage/partitions.go

@@ -0,0 +1,123 @@
+package storage
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// Partitions as places (agent v0.158.0) — felhom.eu architecture/16-storage-physical-identity.md §6.
+//
+// A disk that passed the WHOLE-disk unclaimed filter (classifyClaim: not the system disk, no LVM/ZFS/RAID/LUKS/swap
+// member on any node, no foreign mount on any node) also lists its partitions, each with its own state:
+//
+//	empty       no filesystem, no children           → „format this part" (self-serve: the agent's probe says blank) —
+//	                                                   only while NO part of the disk is mounted (Formattable)
+//	filesystem  ext4/xfs (mountable) or another fs   → „use this part" when mountable; „format this part" only through
+//	                                                   the customer-confirmed data-bearing path (the agent's own probe)
+//	in_use      already Felhom's own drive           → shown, never offered (it is a registered drive already)
+//
+// A partition with children (LVM, a mapper) is not listed. The design's separate „a filesystem with no files" state is
+// folded into `filesystem` on purpose: telling the two apart needs a root read-only mount, and the data-bearing path's
+// confirmation is the safer default for both (`16` §13). Creating, deleting or resizing a partition: never here (D5).
+// The format binding is the partition's own by-id link (…-partN: the disk id + the partition number) via
+// DeviceDurableID, re-resolved before mkfs (wipe_reresolve.go); the attach key is its fs-UUID.
+type CandidatePartition struct {
+	Device    string `json:"device"` // e.g. /dev/sdb2
+	Number    int    `json:"number,omitempty"`
+	SizeBytes int64  `json:"size_bytes"`
+	FSType    string `json:"fstype,omitempty"`
+	State     string `json:"state"` // empty | filesystem | in_use
+	Mountable bool   `json:"mountable"`
+	DurableID string `json:"durable_id,omitempty"` // uuid:<fs-uuid> — the attach key ("" when empty)
+	MountedAt string `json:"mounted_at,omitempty"` // in_use: Felhom's own mount
+	// Formattable is false when ANY node of the disk is mounted (another part in use): the root mkfs wrapper refuses
+	// every mount outside /mnt/felhom-drives on the disk and deliberately does not trust a sibling that claims to be
+	// Felhom's own (a compromised agent could fake that). Such a part can still be USED (attach erases nothing).
+	Formattable bool `json:"formattable"`
+}
+
+const (
+	PartEmpty      = "empty"
+	PartFilesystem = "filesystem"
+	PartInUse      = "in_use"
+)
+
+// candidatePartitions is the pure lister: the whole disk's lsblk tree → its partitions. sizeOf/numberOf read /sys,
+// uuidOf the by-uuid links, owned is the set of mountpoints corroborated as Felhom's own (felhomOwnedMounts).
+func candidatePartitions(lsblkJSON []byte, wholeName string, sizeOf func(string) int64, numberOf func(string) int,
+	uuidOf func(string) (string, bool), owned map[string]bool) []CandidatePartition {
+	var doc struct {
+		BlockDevices []lsblkDev `json:"blockdevices"`
+	}
+	if json.Unmarshal(lsblkJSON, &doc) != nil {
+		return nil
+	}
+	var out []CandidatePartition
+	for _, d := range doc.BlockDevices {
+		if d.Name != wholeName {
+			continue
+		}
+		diskMounted := d.MountPoint != ""
+		var walk func(n lsblkDev)
+		walk = func(n lsblkDev) {
+			if n.MountPoint != "" {
+				diskMounted = true
+			}
+			for _, c := range n.Children {
+				walk(c)
+			}
+		}
+		for _, c := range d.Children {
+			walk(c)
+		}
+		for _, p := range d.Children {
+			if len(p.Children) > 0 || memberFSTypes[p.FSType] {
+				continue // LVM/mapper on it, or a member: not a place (the disk filter refuses these anyway)
+			}
+			c := CandidatePartition{Device: "/dev/" + p.Name, Number: numberOf(p.Name), SizeBytes: sizeOf(p.Name), FSType: p.FSType}
+			switch {
+			case p.MountPoint != "" && (underFelhomDrives(p.MountPoint) || owned[p.MountPoint]):
+				c.State, c.MountedAt = PartInUse, p.MountPoint
+			case p.MountPoint != "":
+				continue // mounted by something else: never offered (the disk filter refuses the disk anyway)
+			case p.FSType == "":
+				c.State = PartEmpty
+			default:
+				c.State = PartFilesystem
+				c.Mountable = mountableFSTypes[p.FSType]
+				if u, ok := uuidOf(c.Device); ok && u != "" {
+					c.DurableID = "uuid:" + u
+				}
+			}
+			c.Formattable = c.State != PartInUse && !diskMounted
+			out = append(out, c)
+		}
+	}
+	return out
+}
+
+// readSysPartNumber reads /sys/class/block/<part>/partition (0 when unreadable).
+func readSysPartNumber(name string) int {
+	b, err := os.ReadFile(filepath.Join("/sys/class/block", name, "partition"))
+	if err != nil {
+		return 0
+	}
+	n, _ := strconv.Atoi(strings.TrimSpace(string(b)))
+	return n
+}
+
+// readSysPartSize reads a partition's size in bytes from /sys/class/block/<part>/size (512-byte sectors).
+func readSysPartSize(name string) int64 {
+	b, err := os.ReadFile(filepath.Join("/sys/class/block", name, "size"))
+	if err != nil {
+		return 0
+	}
+	s, err := strconv.ParseInt(strings.TrimSpace(string(b)), 10, 64)
+	if err != nil {
+		return 0
+	}
+	return s * 512
+}

internal/storage/partitions_test.go

@@ -0,0 +1,91 @@
+package storage
+
+import (
+	"strings"
+	"testing"
+)
+
+// Partitions as places (felhom.eu architecture/16 §6, agent v0.158.0): every partition of a free disk with its own
+// state; Felhom's own drive shown but never offered; anything foreign, layered or a member never listed.
+
+const partTree = `{"blockdevices":[
+ {"name":"sdb","fstype":null,"mountpoint":null,"children":[
+   {"name":"sdb1","fstype":"ext4","mountpoint":"/mnt/felhom-drives/hdd_1"},
+   {"name":"sdb2","fstype":null,"mountpoint":null},
+   {"name":"sdb3","fstype":"ntfs","mountpoint":null},
+   {"name":"sdb4","fstype":"xfs","mountpoint":null},
+   {"name":"sdb5","fstype":"ext4","mountpoint":"/mnt/films"},
+   {"name":"sdb6","fstype":"ext4","mountpoint":"/srv/data"},
+   {"name":"sdb7","fstype":"LVM2_member","mountpoint":null,"children":[{"name":"vg-lv","fstype":"ext4","mountpoint":null}]},
+   {"name":"sdb8","fstype":"crypto_LUKS","mountpoint":null}
+ ]},
+ {"name":"sdc","fstype":null,"mountpoint":null,"children":[{"name":"sdc1","fstype":null,"mountpoint":null}]}
+]}`
+
+func listParts(owned map[string]bool) map[string]CandidatePartition {
+	got := candidatePartitions([]byte(partTree), "sdb",
+		func(n string) int64 { return int64(len(n)) << 30 },
+		func(n string) int { return int(n[len(n)-1] - '0') },
+		func(dev string) (string, bool) { return "uuid-of-" + strings.TrimPrefix(dev, "/dev/"), true },
+		owned)
+	m := map[string]CandidatePartition{}
+	for _, p := range got {
+		m[p.Device] = p
+	}
+	return m
+}
+
+func TestPartitions_StatesPerPartition(t *testing.T) {
+	m := listParts(map[string]bool{"/mnt/films": true})
+	want := map[string]string{"/dev/sdb1": PartInUse, "/dev/sdb2": PartEmpty, "/dev/sdb3": PartFilesystem,
+		"/dev/sdb4": PartFilesystem, "/dev/sdb5": PartInUse}
+	if len(m) != len(want) {
+		t.Fatalf("want exactly %d listed partitions, got %+v", len(want), m)
+	}
+	for dev, st := range want {
+		if m[dev].State != st {
+			t.Fatalf("%s: want %s, got %+v", dev, st, m[dev])
+		}
+	}
+	if m["/dev/sdb2"].DurableID != "" || m["/dev/sdb2"].Mountable {
+		t.Fatalf("an empty part has no attach key: %+v", m["/dev/sdb2"])
+	}
+	if !m["/dev/sdb4"].Mountable || m["/dev/sdb4"].DurableID != "uuid:uuid-of-sdb4" || m["/dev/sdb4"].Number != 4 {
+		t.Fatalf("an xfs part is usable by its fs-UUID: %+v", m["/dev/sdb4"])
+	}
+	if m["/dev/sdb3"].Mountable {
+		t.Fatalf("ntfs is a filesystem the agent does not mount as-is: %+v", m["/dev/sdb3"])
+	}
+}
+
+// A raw /mnt/<name> mount counts as Felhom's own ONLY when corroborated (felhomOwnedMounts); else it is foreign and
+// the part is not listed. Positive control: TestPartitions_StatesPerPartition (the same mount, corroborated).
+func TestPartitions_UncorroboratedMountIsNotOffered(t *testing.T) {
+	m := listParts(nil)
+	if _, ok := m["/dev/sdb5"]; ok {
+		t.Fatalf("an uncorroborated /mnt/films mount must not be listed, got %+v", m["/dev/sdb5"])
+	}
+	for _, dev := range []string{"/dev/sdb6", "/dev/sdb7", "/dev/sdb8", "/dev/sdc1"} {
+		if _, ok := m[dev]; ok {
+			t.Fatalf("%s must never be listed (foreign mount, LVM, LUKS, another disk)", dev)
+		}
+	}
+}
+
+// The root wrapper refuses any format on a disk with a mounted node (and trusts no „it is Felhom's own" claim), so a
+// part next to a mounted one is never offered for formatting — only for use. Positive control: an unmounted disk.
+func TestPartitions_FormattableOnlyWhenNothingOnTheDiskIsMounted(t *testing.T) {
+	m := listParts(map[string]bool{"/mnt/films": true})
+	for dev, p := range m {
+		if p.Formattable {
+			t.Fatalf("%s: a part of a disk with a mounted part must not be formattable: %+v", dev, p)
+		}
+	}
+	free := `{"blockdevices":[{"name":"sdc","fstype":null,"mountpoint":null,"children":[
+	  {"name":"sdc1","fstype":null,"mountpoint":null},{"name":"sdc2","fstype":"ext4","mountpoint":null}]}]}`
+	got := candidatePartitions([]byte(free), "sdc", func(string) int64 { return 1 << 30 }, func(string) int { return 1 },
+		func(string) (string, bool) { return "u", true }, nil)
+	if len(got) != 2 || !got[0].Formattable || !got[1].Formattable {
+		t.Fatalf("parts of an unmounted disk are formattable, got %+v", got)
+	}
+}

internal/vzpartial/vzpartial.go

@@ -0,0 +1,208 @@
+// Package vzpartial removes a dead, half-written vzdump backup of a guest from a local dir storage (R-1006).
+//
+// A power cut during the night's whole-guest backup leaves `vzdump-lxc-<vmid>-<date>.tar.dat` and its `.tmp/` directory
+// on the target (demo-hp 2026-10-14: 12.2 GB on the host root). Nothing removes them: Proxmox does not list them as
+// backups, every later backup is skipped „not enough space", and a host root that fills up breaks LVM's own metadata
+// writes (audits/power-cut-fixes-2026-10-14 C4). This package finds such a leftover and asks the root helper
+// /usr/local/sbin/felhom-vzdump-partial-clean to remove it; the helper re-checks every rule as root.
+//
+// Rules here (the helper repeats them, and adds the open-file check the agent cannot do):
+//   - only a `dir` storage; only names of the exact vzdump pattern for that vmid (NamePattern) — never a finished
+//     archive, a log, another guest;
+//   - only when no vzdump for that vmid is in flight (the R-1008 answer: a task from before the boot is not in flight);
+//   - only when dead: last modified before this boot, or untouched for QuietFor.
+//
+// Any doubt leaves the entry and logs why. Pinned by vzpartial_test.go.
+package vzpartial
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// Helper is the root helper's installed path (configs/felhom-vzdump-partial-clean, delivered by the config bundle).
+const Helper = "/usr/local/sbin/felhom-vzdump-partial-clean"
+
+// QuietFor is how long an entry written in THIS boot must be untouched before it counts as dead (the helper's QUIET_S).
+const QuietFor = 120 * time.Second
+
+// NamePattern matches the half-written entries of one guest: the archive being written (.tar.dat / .vma.dat) and the
+// temporary directory (.tmp). The timestamp is vzdump's own (host local time).
+func NamePattern(vmid int) *regexp.Regexp {
+	return regexp.MustCompile(`^vzdump-(lxc|qemu)-` + strconv.Itoa(vmid) +
+		`-[0-9]{4}_[0-9]{2}_[0-9]{2}-[0-9]{2}_[0-9]{2}_[0-9]{2}\.(tar\.dat|vma\.dat|tmp)$`)
+}
+
+// Entry is one leftover found in the dump directory.
+type Entry struct {
+	Name    string
+	Dir     bool
+	ModTime time.Time
+	Size    int64
+}
+
+// Candidates lists the entries of dumpDir that match vmid's half-written pattern. A missing directory is no error.
+func Candidates(dumpDir string, vmid int) ([]Entry, error) {
+	ents, err := os.ReadDir(dumpDir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	re := NamePattern(vmid)
+	var out []Entry
+	for _, e := range ents {
+		if !re.MatchString(e.Name()) || e.Type()&os.ModeSymlink != 0 {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		if strings.HasSuffix(e.Name(), ".tmp") != info.IsDir() {
+			continue // a .tmp that is not a directory, or an archive name that is one: not vzdump's
+		}
+		mt := info.ModTime()
+		if info.IsDir() {
+			mt = newestUnder(filepath.Join(dumpDir, e.Name()), mt)
+		}
+		out = append(out, Entry{Name: e.Name(), Dir: info.IsDir(), ModTime: mt, Size: info.Size()})
+	}
+	return out, nil
+}
+
+func newestUnder(dir string, mt time.Time) time.Time {
+	_ = filepath.WalkDir(dir, func(_ string, d os.DirEntry, err error) error {
+		if err != nil {
+			return nil
+		}
+		if i, e := d.Info(); e == nil && i.ModTime().After(mt) {
+			mt = i.ModTime()
+		}
+		return nil
+	})
+	return mt
+}
+
+// Dead decides whether an entry is dead: written before this boot, or untouched for QuietFor. bootOK=false (the boot
+// time could not be read) leaves only the quiet rule.
+func Dead(e Entry, boot time.Time, bootOK bool, now time.Time) (bool, string) {
+	if bootOK && e.ModTime.Before(boot) {
+		return true, "written before this boot"
+	}
+	if age := now.Sub(e.ModTime); age >= QuietFor {
+		return true, "untouched for " + age.Round(time.Second).String()
+	}
+	return false, "modified " + now.Sub(e.ModTime).Round(time.Second).String() + " ago — may still be written"
+}
+
+// StorageAPI is the one Proxmox read the cleaner needs (the storage's type and path).
+type StorageAPI interface {
+	ListStorage(ctx context.Context) ([]proxmox.Storage, error)
+}
+
+// Cleaner removes dead leftovers. All fields but Logger and Now are required; a nil Cleaner is a no-op.
+type Cleaner struct {
+	API      StorageAPI
+	Runner   proxmox.Runner // the fenced sudo runner
+	InFlight func(ctx context.Context, vmid int) (bool, error)
+	Boot     func() (int64, bool)
+	Logger   *slog.Logger
+	Now      func() time.Time
+	// dumpDir maps a storage path to its dump directory (tests); nil = <path>/dump.
+	dumpDir func(path string) string
+}
+
+// Result is one removal or one entry left in place.
+type Result struct {
+	Entry   Entry
+	Removed bool
+	Why     string
+}
+
+// Clean removes the dead leftovers of vmid on storage. It never returns an error for „nothing to do"; every entry it
+// finds is logged with what was done and why.
+func (c *Cleaner) Clean(ctx context.Context, storage string, vmid int) []Result {
+	if c == nil || c.API == nil || c.Runner == nil || c.InFlight == nil || c.Boot == nil {
+		return nil
+	}
+	log := c.Logger
+	if log == nil {
+		log = slog.Default()
+	}
+	now := time.Now
+	if c.Now != nil {
+		now = c.Now
+	}
+	stores, err := c.API.ListStorage(ctx)
+	if err != nil {
+		log.Warn("vzdump-partial: storage list unreadable — not looking for leftovers", "storage", storage, "err", err)
+		return nil
+	}
+	var st *proxmox.Storage
+	for i := range stores {
+		if stores[i].Storage == storage {
+			st = &stores[i]
+			break
+		}
+	}
+	if st == nil || st.Type != "dir" || st.Path == "" {
+		return nil // PBS, LVM, NFS …: vzdump does not leave a .tar.dat there that this agent may remove
+	}
+	dump := filepath.Join(st.Path, "dump")
+	if c.dumpDir != nil {
+		dump = c.dumpDir(st.Path)
+	}
+	ents, err := Candidates(dump, vmid)
+	if err != nil {
+		log.Warn("vzdump-partial: dump directory unreadable", "dir", dump, "err", err)
+		return nil
+	}
+	if len(ents) == 0 {
+		return nil
+	}
+	var out []Result
+	inFlight, err := c.InFlight(ctx, vmid)
+	if err != nil || inFlight {
+		why := "a backup of this guest is in flight"
+		if err != nil {
+			why = "cannot tell whether a backup is in flight: " + err.Error()
+		}
+		for _, e := range ents {
+			log.Info("vzdump-partial: leaving a half-written backup", "storage", storage, "vmid", vmid, "name", e.Name, "why", why)
+			out = append(out, Result{Entry: e, Why: why})
+		}
+		return out
+	}
+	b, bootOK := c.Boot()
+	boot := time.Unix(b, 0)
+	for _, e := range ents {
+		dead, why := Dead(e, boot, bootOK, now())
+		if !dead {
+			log.Info("vzdump-partial: leaving a half-written backup", "storage", storage, "vmid", vmid, "name", e.Name, "why", why)
+			out = append(out, Result{Entry: e, Why: why})
+			continue
+		}
+		stdout, stderr, err := c.Runner.Run(ctx, Helper, storage, strconv.Itoa(vmid), e.Name)
+		if err != nil {
+			why = fmt.Sprintf("the root helper refused: %s", strings.TrimSpace(string(stderr)))
+			log.Warn("vzdump-partial: leaving a half-written backup", "storage", storage, "vmid", vmid, "name", e.Name, "why", why, "err", err)
+			out = append(out, Result{Entry: e, Why: why})
+			continue
+		}
+		log.Warn("vzdump-partial: removed a dead half-written backup", "storage", storage, "vmid", vmid, "name", e.Name,
+			"bytes", e.Size, "why", why, "helper", strings.TrimSpace(string(stdout)))
+		out = append(out, Result{Entry: e, Removed: true, Why: why})
+	}
+	return out
+}

internal/vzpartial/vzpartial_test.go

@@ -0,0 +1,206 @@
+package vzpartial
+
+import (
+	"context"
+	"errors"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+const vmid = 9201
+const name = "vzdump-lxc-9201-2026_10_14-10_42_25"
+
+var boot = time.Unix(1791967481, 0)
+
+type fakeAPI struct{ stores []proxmox.Storage }
+
+func (f fakeAPI) ListStorage(context.Context) ([]proxmox.Storage, error) { return f.stores, nil }
+
+type fakeRunner struct {
+	calls [][]string
+	err   error
+}
+
+func (r *fakeRunner) Run(_ context.Context, n string, a ...string) ([]byte, []byte, error) {
+	r.calls = append(r.calls, append([]string{n}, a...))
+	if r.err != nil {
+		return nil, []byte("REFUSED: in use"), r.err
+	}
+	return []byte("removed"), nil, nil
+}
+func (r *fakeRunner) RunStdin(ctx context.Context, _ io.Reader, n string, a ...string) ([]byte, []byte, error) {
+	return r.Run(ctx, n, a...)
+}
+
+type rig struct {
+	dump   string
+	runner *fakeRunner
+	c      *Cleaner
+}
+
+func newRig(t *testing.T, storeType string, inFlight bool, inErr error) *rig {
+	t.Helper()
+	root := t.TempDir()
+	dump := filepath.Join(root, "dump")
+	if err := os.MkdirAll(dump, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	r := &rig{dump: dump, runner: &fakeRunner{}}
+	r.c = &Cleaner{
+		API:      fakeAPI{stores: []proxmox.Storage{{Storage: "local", Type: storeType, Path: root}}},
+		Runner:   r.runner,
+		InFlight: func(context.Context, int) (bool, error) { return inFlight, inErr },
+		Boot:     func() (int64, bool) { return boot.Unix(), true },
+		Now:      func() time.Time { return boot.Add(5 * time.Minute) },
+	}
+	return r
+}
+
+func (r *rig) put(t *testing.T, n string, dir bool, mt time.Time) {
+	t.Helper()
+	p := filepath.Join(r.dump, n)
+	if dir {
+		if err := os.MkdirAll(filepath.Join(p, "etc"), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		_ = os.Chtimes(filepath.Join(p, "etc"), mt, mt)
+	} else if err := os.WriteFile(p, []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	_ = os.Chtimes(p, mt, mt)
+}
+
+func (r *rig) asked() []string {
+	var out []string
+	for _, c := range r.runner.calls {
+		if len(c) == 4 && c[0] == Helper && c[1] == "local" && c[2] == "9201" {
+			out = append(out, c[3])
+		}
+	}
+	return out
+}
+
+// RED-PROOF: remove the `bootOK && e.ModTime.Before(boot)` rule in Dead → a pre-boot entry modified 1 min before the
+// boot is still „untouched for 6m" — so the test uses a 1-min-old-at-boot entry AND a Now 30 s after the boot.
+func TestClean_RemovesDeadPartialAndTmp(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	r.c.Now = func() time.Time { return boot.Add(30 * time.Second) }
+	r.put(t, name+".tar.dat", false, boot.Add(-time.Minute))
+	r.put(t, name+".tmp", true, boot.Add(-time.Minute))
+	res := r.c.Clean(context.Background(), "local", vmid)
+	if got := r.asked(); len(got) != 2 {
+		t.Fatalf("both dead entries must go to the helper, got %v", got)
+	}
+	for _, x := range res {
+		if !x.Removed || x.Why != "written before this boot" {
+			t.Fatalf("%+v", x)
+		}
+	}
+}
+
+func TestClean_RemovesQuietPartialOfThisBoot(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	r.put(t, name+".tar.dat", false, boot.Add(time.Minute)) // 4 min before Now
+	r.c.Clean(context.Background(), "local", vmid)
+	if len(r.asked()) != 1 {
+		t.Fatal("a partial untouched for QuietFor must be removed")
+	}
+}
+
+// Each keep has its positive control (the dead pre-boot partial in the same rig IS asked for).
+func TestClean_Keeps(t *testing.T) {
+	cases := map[string]func(t *testing.T) (*rig, string){
+		// RED-PROOF: drop the InFlight check in Clean → the in-flight partial is asked for → fails.
+		"in flight": func(t *testing.T) (*rig, string) { return newRig(t, "dir", true, nil), name + ".tar.dat" },
+		"in-flight unknown": func(t *testing.T) (*rig, string) {
+			return newRig(t, "dir", false, errors.New("api down")), name + ".tar.dat"
+		},
+		// RED-PROOF: drop the `st.Type != "dir"` test → an lvmthin target is cleaned → fails.
+		"not a dir storage": func(t *testing.T) (*rig, string) { return newRig(t, "lvmthin", false, nil), name + ".tar.dat" },
+	}
+	for what, mk := range cases {
+		r, n := mk(t)
+		r.put(t, n, false, boot.Add(-time.Hour))
+		r.c.Clean(context.Background(), "local", vmid)
+		if len(r.asked()) != 0 {
+			t.Fatalf("%s: must keep, helper asked for %v", what, r.asked())
+		}
+		ctl := newRig(t, "dir", false, nil)
+		ctl.put(t, n, false, boot.Add(-time.Hour))
+		ctl.c.Clean(context.Background(), "local", vmid)
+		if len(ctl.asked()) != 1 {
+			t.Fatalf("%s: positive control not removed", what)
+		}
+	}
+}
+
+// RED-PROOF: weaken NamePattern to `vzdump-.*` → the finished archive / log / other guest's partial are asked for.
+func TestClean_OnlyThisGuestsHalfWrittenNames(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	old := boot.Add(-time.Hour)
+	for _, n := range []string{name + ".tar.zst", name + ".log", name + ".tar.zst.notes", "vzdump-lxc-9202-2026_10_14-10_42_25.tar.dat",
+		"vzdump-lxc-92011-2026_10_14-10_42_25.tar.dat", name + ".tar.dat.bak", name + ".tar.da", "x" + name + ".tar.dat"} {
+		r.put(t, n, false, old)
+	}
+	r.put(t, name+".tar.dat", false, old) // the positive control in the same directory
+	r.c.Clean(context.Background(), "local", vmid)
+	if got := r.asked(); len(got) != 1 || got[0] != name+".tar.dat" {
+		t.Fatalf("only %s.tar.dat may be asked for, got %v", name, got)
+	}
+}
+
+func TestClean_KeepsRecentAndWrongKindAndSymlink(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	r.put(t, name+".tar.dat", false, boot.Add(4*time.Minute))                            // 1 min before Now: may still be written
+	r.put(t, "vzdump-lxc-9201-2026_10_14-11_00_00.tmp", false, boot.Add(-time.Hour))     // a FILE named .tmp
+	r.put(t, "vzdump-lxc-9201-2026_10_14-13_00_00.tar.dat", false, boot.Add(-time.Hour)) // positive control
+	r.c.Clean(context.Background(), "local", vmid)
+	if got := r.asked(); len(got) != 1 || got[0] != "vzdump-lxc-9201-2026_10_14-13_00_00.tar.dat" {
+		t.Fatalf("only the positive control may be asked for, got %v", got)
+	}
+}
+
+// RED-PROOF: drop the ModeSymlink skip in Candidates → the symlink (quiet: Now is an hour ahead) is asked for → fails.
+func TestClean_KeepsSymlink(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	r.c.Now = func() time.Time { return time.Now().Add(time.Hour) }
+	target := filepath.Join(r.dump, "elsewhere")
+	_ = os.WriteFile(target, []byte("x"), 0o644)
+	_ = os.Symlink(target, filepath.Join(r.dump, "vzdump-lxc-9201-2026_10_14-12_00_00.tar.dat"))
+	r.put(t, "vzdump-lxc-9201-2026_10_14-13_00_00.tar.dat", false, boot.Add(-time.Hour)) // positive control
+	r.c.Clean(context.Background(), "local", vmid)
+	if got := r.asked(); len(got) != 1 || got[0] != "vzdump-lxc-9201-2026_10_14-13_00_00.tar.dat" {
+		t.Fatalf("only the positive control may be asked for, got %v", got)
+	}
+}
+
+func TestClean_HelperRefusalIsNotARemoval(t *testing.T) {
+	r := newRig(t, "dir", false, nil)
+	r.runner.err = errors.New("exit status 1")
+	r.put(t, name+".tar.dat", false, boot.Add(-time.Hour))
+	res := r.c.Clean(context.Background(), "local", vmid)
+	if len(res) != 1 || res[0].Removed {
+		t.Fatalf("a refused helper call must not count as removed: %+v", res)
+	}
+}
+
+// The root helper's own tests (configs/test_felhom_vzdump_partial_clean.py) run with the Go suite.
+func TestRootHelperPythonSuite(t *testing.T) {
+	py, err := exec.LookPath("python3")
+	if err != nil {
+		t.Skip("python3 not found")
+	}
+	_, file, _, _ := runtime.Caller(0)
+	script := filepath.Join(filepath.Dir(file), "..", "..", "configs", "test_felhom_vzdump_partial_clean.py")
+	out, err := exec.Command(py, script).CombinedOutput()
+	if err != nil {
+		t.Fatalf("helper suite failed: %v\n%s", err, out)
+	}
+}