fix disk info collection

src/internal/qmmonitor/block.go

@@ -3,6 +3,7 @@ package qmmonitor
 import (
 	"encoding/json"
 	"fmt"
+	"log/slog"
 	"regexp"
 	"strings"
 )
@@ -95,13 +96,7 @@ func ParseBlockInfo(raw string) map[string]DiskInfo {
 				info.Labels["attached_to"] = val
 			} else if strings.HasPrefix(line, "Cache mode:") {
 				val := strings.TrimSpace(strings.TrimPrefix(line, "Cache mode:"))
-				for _, mode := range strings.Split(val, ", ") {
-					mode = strings.TrimSpace(mode)
-					if mode != "" {
-						key := "cache_mode_" + strings.ReplaceAll(mode, " ", "_")
-						info.Labels[key] = "true"
-					}
-				}
+				info.Labels["cache_mode"] = val
 			} else if strings.HasPrefix(line, "Detect zeroes:") {
 				info.Labels["detect_zeroes"] = "on"
 			}
@@ -110,6 +105,9 @@ func ParseBlockInfo(raw string) map[string]DiskInfo {
 		result[diskName] = info
 	}
 
+	if len(result) == 0 && raw != "" {
+		slog.Debug("ParseBlockInfo found no disks", "rawLen", len(raw))
+	}
 	return result
 }
 

src/internal/qmmonitor/block_test.go

@@ -27,11 +27,8 @@ func TestParseBlockInfo_Qcow2(t *testing.T) {
 	if d.Labels["detect_zeroes"] != "on" {
 		t.Errorf("detect_zeroes = %q", d.Labels["detect_zeroes"])
 	}
-	if d.Labels["cache_mode_writeback"] != "true" {
-		t.Errorf("cache_mode_writeback missing")
-	}
-	if d.Labels["cache_mode_direct"] != "true" {
-		t.Errorf("cache_mode_direct missing")
+	if d.Labels["cache_mode"] != "writeback, direct" {
+		t.Errorf("cache_mode = %q, want %q", d.Labels["cache_mode"], "writeback, direct")
 	}
 }