lxd/fsmonitor/drivers: Only log fanotify load errors if filesystem is…

… mount point.

Signed-off-by: Mark Laing <mark.laing@canonical.com>

lxd/fsmonitor/drivers/load.go

@@ -7,6 +7,7 @@ import (
 	"os"
 
 	"github.com/canonical/lxd/lxd/fsmonitor"
+	"github.com/canonical/lxd/lxd/storage/filesystem"
 	"github.com/canonical/lxd/shared/logger"
 )
 
@@ -46,9 +47,18 @@ func Load(ctx context.Context, path string, events ...fsmonitor.Event) (fsmonito
 		return startMonitor(driverName)
 	}
 
-	driver, err := startMonitor(fsmonitor.DriverNameFANotify)
-	if err != nil {
-		logger.Warn("Failed to initialize fanotify, falling back on inotify", logger.Ctx{"err": err})
+	var driver fsmonitor.FSMonitor
+	var err error
+	if filesystem.IsMountPoint(path) {
+		// If the file system is a mount point, try to use fanotify but fall back to inotify.
+		driver, err = startMonitor(fsmonitor.DriverNameFANotify)
+		if err != nil {
+			logger.Warn("Failed to initialize fanotify, falling back on inotify", logger.Ctx{"err": err, "path": path})
+		}
+	}
+
+	// If the file system is not a mount point or if setting up fanotify fails for another reason, use inotify.
+	if driver == nil {
 		driver, err = startMonitor(fsmonitor.DriverNameINotify)
 		if err != nil {
 			return nil, err