Operator ruling 2026-07-13: walk the root's backing device through /sys/block/<dev>/slaves
recursively down to physical disks (dm AND md; topology, never VG names); those + any mounted-ESP
holder are system; the all-system fail-safe returns to being the WALK-FAILURE error case only.
SAFETY DIRECTION: a root-backing disk classified candidate is made impossible — per-branch
conservatism (any unresolvable slave fails the WHOLE walk -> ok=false -> the unchanged all-system
path).
- physicalDisksOf/walkSlaves in role.go (symlink canon -> wholeDiskOf fast path -> recursive
slaves walk; cycle/depth guard; non-/dev sources unwalkable)
- HostReader.BlockSlaves(name) — the ONE new seam method; ProcHostReader reads
/sys/block/<name>/slaves; all four test fakes mirror it
- role_walk_test.go: signature table (root-backing disk ALWAYS system across legacy-LVM /
md-raid / EFI+raw / EFI+LVM / nested dm-on-md — NEVER weaken) + dead-wizard-lives +
dangling-slave fail-safe (real sysKnown=false path) + cycle + empty-slaves; red-proofs A/B/D
run->fail->revert (recorded in REPORT)
- §3 spike transcripts (drill legacy: dm-1->sda3->sda; felhom-pve: ESP+walk agree on sda ->
byte-identical regression); caller audit: none relied on all-system as a feature
- format/mkfs paths, data-bearing guards, wizard UI untouched
durableIDForMount was Observe-only, so a raw (non-PVE-storage) drive's enroll
intent + guest-bind went unrecorded ("durable-id unresolved") — it mounted+bound
but wasn't intent-tracked (RegistryKnownTargets skips intent==new). Fall back to
resolving the mount's device fs-UUID (HostReader.Mounts + ResolveUUID) →
uuid:<fs-uuid>, same scheme as Observe. Test + red-proof. Residual:
ReassertGuestBinds still Observe-based (raw guest-bind not re-asserted post-reboot).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>