filesystem: fix mountTimeout not working issue

Signed-off-by: 董薇 <dongw1@chinatelecom.cn>

collector/filesystem_linux.go

@@ -122,7 +122,6 @@ func (c *filesystemCollector) processStat(labels filesystemLabels) filesystemSta
 
 	buf := new(unix.Statfs_t)
 	err := unix.Statfs(rootfsFilePath(labels.mountPoint), buf)
-	stuckMountsMtx.Lock()
 	close(success)
 
 	if err != nil {
@@ -155,11 +154,12 @@ func stuckMountWatcher(mountPoint string, success chan struct{}, logger log.Logg
 	case <-success:
 		// Success
 		// If the mount has been marked as stuck, unmark it and log it's recovery.
+		stuckMountsMtx.Lock()
+		defer stuckMountsMtx.Unlock()
 		if _, ok := stuckMounts[mountPoint]; ok {
 			level.Debug(logger).Log("msg", "Mount point has recovered, monitoring will resume", "mountpoint", mountPoint)
 			delete(stuckMounts, mountPoint)
 		}
-		stuckMountsMtx.Unlock()
 	case <-mountCheckTimer.C:
 		// Timed out, mark mount as stuck
 		stuckMountsMtx.Lock()
@@ -171,7 +171,6 @@ func stuckMountWatcher(mountPoint string, success chan struct{}, logger log.Logg
 				level.Debug(logger).Log("msg", "Mount point has recovered, monitoring will resume", "mountpoint", mountPoint)
 				delete(stuckMounts, mountPoint)
 			}
-			stuckMountsMtx.Unlock()
 		default:
 			level.Debug(logger).Log("msg", "Mount point timed out, it is being labeled as stuck and will not be monitored", "mountpoint", mountPoint)
 			stuckMounts[mountPoint] = struct{}{}