v0.318.0: the internal data place, partitions, an honest whole-box backup offer (R-1084), sys_drive never offered (R-1082)

felhom.eu architecture/16 §4-§6 (build B). MinAgent 0.157.0 — the internal place and the partitions appear only when
agent >= 0.158.0 reports them. Tests red-proved; four parity fixtures refreshed (only the new lines).

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

controller/internal/web/partitions_test.go

@@ -0,0 +1,99 @@
+package web
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-controller/internal/agentapi"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
+)
+
+// Partitions as places (felhom.eu architecture/16 §6, v0.318.0): the free part of a disk whose other part is a
+// registered drive stays on offer; the whole disk never does — in the list AND on the server.
+
+const partMounts = `/dev/mapper/pve-root /mnt/felhom-drives ext4 rw,relatime 0 0
+/dev/sdb1 /mnt/felhom-drives/hdd_1 ext4 rw,relatime 0 0
+/dev/mapper/pve-vm--9201--disk--1 /mnt/sys_drive ext4 rw,relatime 0 0
+`
+
+func diskWithParts() agentapi.DiskCandidate {
+	return agentapi.DiskCandidate{Device: "/dev/sdb", MountSource: "/dev/sdb1", FSType: "ext4", DataBearing: true,
+		Partitions: []agentapi.CandidatePartition{
+			{Device: "/dev/sdb1", Number: 1, FSType: "ext4", State: agentapi.PartInUse, MountedAt: "/mnt/felhom-drives/hdd_1"},
+			{Device: "/dev/sdb2", Number: 2, State: agentapi.PartEmpty},
+			{Device: "/dev/sdb3", Number: 3, FSType: "ext4", State: agentapi.PartFilesystem, Mountable: true, DurableID: "uuid:3333"},
+		}}
+}
+
+func TestPartitions_FreePartsOfAnInUseDiskStayOffered(t *testing.T) {
+	reg := map[string]bool{"/mnt/felhom-drives/hdd_1": true}
+	got := dropRegisteredDrives(agentapi.CandidatesResult{Initialize: []agentapi.DiskCandidate{diskWithParts()}}, partMounts, reg)
+	if len(got.Initialize) != 1 {
+		t.Fatalf("the disk must stay listed for its free parts, got %+v", got.Initialize)
+	}
+	c := got.Initialize[0]
+	if !c.WholeDiskInUse {
+		t.Fatalf("the whole disk must be marked in use (no whole-disk action): %+v", c)
+	}
+	if len(c.Partitions) != 2 || c.Partitions[0].Device != "/dev/sdb2" || c.Partitions[1].Device != "/dev/sdb3" {
+		t.Fatalf("only the free parts may be offered, got %+v", c.Partitions)
+	}
+}
+
+// R-542 unchanged: a disk with nothing free is still dropped.
+func TestPartitions_InUseDiskWithNoFreePartIsDropped(t *testing.T) {
+	d := diskWithParts()
+	d.Partitions = d.Partitions[:1]
+	got := dropRegisteredDrives(agentapi.CandidatesResult{Initialize: []agentapi.DiskCandidate{d}}, partMounts, map[string]bool{"/mnt/felhom-drives/hdd_1": true})
+	if len(got.Initialize) != 0 {
+		t.Fatalf("a disk with no free part must not be offered, got %+v", got.Initialize)
+	}
+}
+
+func TestPartitions_ServerRefusesTheWholeDiskButNotTheFreePart(t *testing.T) {
+	reg := map[string]bool{"/mnt/felhom-drives/hdd_1": true}
+	for dev, want := range map[string]bool{"/dev/sdb": true, "/dev/sdb1": true, "/dev/sdb2": false, "/dev/sdc": false} {
+		if got := deviceBacksRegistered(dev, partMounts, reg); got != want {
+			t.Errorf("%s: backs a registered drive = %v, want %v", dev, got, want)
+		}
+	}
+	if !deviceBacksRegistered("/dev/sdc", "", reg) {
+		t.Errorf("an unreadable mount table must refuse (fail-safe)")
+	}
+}
+
+func TestPartitions_AFormattedPartsUUIDIsFound(t *testing.T) {
+	ag := &mockAgent{candidates: agentapi.CandidatesResult{Initialize: []agentapi.DiskCandidate{diskWithParts()}}}
+	if got := resolveEnrollUUID(context.Background(), ag, "/dev/sdb3"); got != "3333" {
+		t.Fatalf("the part's new filesystem must be found for the mount, got %q", got)
+	}
+}
+
+// The handler asks before it starts anything: the whole disk under a registered part → 409, never a format job.
+// Positive control: the free part passes the guard and reaches the agent step (503 here: no agent configured).
+func TestPartitions_InitHandlerRefusesTheWholeDisk(t *testing.T) {
+	s := testServer(t)
+	s.mountsFn = func() string { return partMounts }
+	if err := s.settings.AddStoragePath(settingsPath("/mnt/felhom-drives/hdd_1")); err != nil {
+		t.Fatal(err)
+	}
+	post := func(dev string) int {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest("POST", "/api/storage/init", strings.NewReader(`{"device":"`+dev+`","fstype":"ext4","mount_name":"films"}`))
+		s.handleStorageInit(w, r)
+		return w.Code
+	}
+	if c := post("/dev/sdb"); c != http.StatusConflict {
+		t.Fatalf("the whole disk under a registered part: want 409, got %d", c)
+	}
+	if c := post("/dev/sdb2"); c == http.StatusConflict {
+		t.Fatalf("positive control: the free part must pass the guard, got %d", c)
+	}
+}
+
+func settingsPath(p string) settings.StoragePath {
+	return settings.StoragePath{Path: p, Schedulable: true}
+}