restore-test: add rootfs override alongside bind-mount overrides

PVE refuses a restore carrying mountpoint params unless rootfs is also set ("mount
points configured, but 'rootfs' not set"). Size the rootfs override from the source
rootfs (rootfsSizeGB/sizeToGB, round up). Validated manually on the host: restore of
bind-mounted 9201 with --rootfs + --mp0/--mp9 overrides boots + tears down cleanly.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/reconcile/restoretest.go

@@ -3,6 +3,7 @@ package reconcile
 import (
 	"context"
 	"fmt"
+	"math"
 	"regexp"
 	"strconv"
 	"strings"
@@ -169,10 +170,21 @@ func (e *Engine) runScratchTest(ctx context.Context, vmid int, spec RestoreTestS
 	var mountOverrides map[string]string
 	if srcVMID, ok := archiveVMID(spec.Archive); ok {
 		if srcCfg, cerr := e.api.GuestConfig(ctx, srcVMID); cerr == nil {
-			mountOverrides = bindMountOverrides(srcCfg.MountPoints(), spec.RestoreStorage)
-			if len(mountOverrides) > 0 {
-				e.logger.Info("restore-test: neutralizing source bind-mount mountpoints for scratch restore",
-					"source_vmid", srcVMID, "scratch", vmid, "count", len(mountOverrides))
+			if binds := bindMountOverrides(srcCfg.MountPoints(), spec.RestoreStorage); len(binds) > 0 {
+				// PVE refuses a restore that carries mountpoint params unless `rootfs` is also set
+				// ("mount points configured, but 'rootfs' not set"). Size the rootfs override from the
+				// SOURCE rootfs (restore needs target >= the archive's volume). Without a parseable
+				// size we can't safely override, so restore as-is (the bind-mount restore then fails
+				// in the verdict rather than risking a wrong rootfs size).
+				if sz := rootfsSizeGB(srcCfg.RootFS); sz > 0 {
+					binds["rootfs"] = fmt.Sprintf("%s:%d", spec.RestoreStorage, sz)
+					mountOverrides = binds
+					e.logger.Info("restore-test: neutralizing source bind-mount mountpoints for scratch restore",
+						"source_vmid", srcVMID, "scratch", vmid, "bind_mounts", len(binds)-1, "rootfs_gb", sz)
+				} else {
+					e.logger.Warn("restore-test: source has bind mounts but rootfs size unparseable — restoring as-is",
+						"source_vmid", srcVMID, "rootfs", srcCfg.RootFS)
+				}
 			}
 		} else {
 			e.logger.Warn("restore-test: could not read source config for mp overrides (restoring as-is)",
@@ -299,6 +311,47 @@ func mountPathOf(opts string) string {
 	return ""
 }
 
+// rootfsSizeGB parses the GB size from a volume spec's "size=<N><unit>" field (e.g.
+// "local-lvm:vm-9201-disk-0,size=8G"), rounding UP to whole GB — a restore needs the target volume
+// >= the archive's. Returns 0 when no size field is present (caller then skips the override).
+func rootfsSizeGB(spec string) int {
+	for _, kv := range strings.Split(spec, ",") {
+		if v, ok := strings.CutPrefix(kv, "size="); ok {
+			return sizeToGB(v)
+		}
+	}
+	return 0
+}
+
+// sizeToGB converts a PVE size string ("8G", "512M", "1T", "8192K") to whole GB, rounding up (min 1
+// when positive). Returns 0 on a malformed value.
+func sizeToGB(s string) int {
+	if s == "" {
+		return 0
+	}
+	mult := 1.0 // default GB if no recognized unit suffix
+	num := s
+	switch s[len(s)-1] {
+	case 'T', 't':
+		mult, num = 1024, s[:len(s)-1]
+	case 'G', 'g':
+		mult, num = 1, s[:len(s)-1]
+	case 'M', 'm':
+		mult, num = 1.0/1024, s[:len(s)-1]
+	case 'K', 'k':
+		mult, num = 1.0/(1024*1024), s[:len(s)-1]
+	}
+	f, err := strconv.ParseFloat(num, 64)
+	if err != nil || f <= 0 {
+		return 0
+	}
+	gb := int(math.Ceil(f * mult))
+	if gb < 1 {
+		gb = 1
+	}
+	return gb
+}
+
 // teardownScratch destroys the scratch guest (benign, gated) and records the entry terminal.
 // On any teardown failure it leaves the entry in-flight so Recover reaps the guest later.
 func (e *Engine) teardownScratch(ctx context.Context, base JournalEntry) {

internal/reconcile/restoretest_mounts_test.go

@@ -46,3 +46,19 @@ func TestBindMountOverrides(t *testing.T) {
 		t.Error("expected nil when there are no bind mounts")
 	}
 }
+
+func TestRootfsSizeGB(t *testing.T) {
+	cases := map[string]int{
+		"local-lvm:vm-9201-disk-0,size=8G": 8,
+		"local-lvm:base,size=512M":         1, // rounds up
+		"local-lvm:base,size=1T":           1024,
+		"local-lvm:base,size=0":            0,
+		"local-lvm:base":                   0, // no size field
+		"local-lvm:base,size=8":            8, // unit-less → GB
+	}
+	for spec, want := range cases {
+		if got := rootfsSizeGB(spec); got != want {
+			t.Errorf("rootfsSizeGB(%q) = %d, want %d", spec, got, want)
+		}
+	}
+}