Fix stat checking for cgroup

Author: Daniil Tulin

api/common/panic_logger.go

@@ -27,6 +27,8 @@ type FusePanicLogger struct {
 	Fs fuseutil.FileSystem
 }
 
+var _ fuseutil.FileSystem = FusePanicLogger{}
+
 func LogPanic(err *error) {
 	if e := recover(); e != nil {
 		log.Errorf("stacktrace from panic: %v \n"+string(debug.Stack()), e)
@@ -36,6 +38,11 @@ func LogPanic(err *error) {
 	}
 }
 
+func (fs FusePanicLogger) BatchForget(ctx context.Context, op *fuseops.BatchForgetOp) (err error) {
+	defer LogPanic(&err)
+	return fs.Fs.BatchForget(ctx, op)
+}
+
 func (fs FusePanicLogger) StatFS(ctx context.Context, op *fuseops.StatFSOp) (err error) {
 	defer LogPanic(&err)
 	return fs.Fs.StatFS(ctx, op)

internal/cgroup.go

@@ -45,7 +45,7 @@ func getCgroupAvailableMem() (retVal uint64, err error) {
 
 	// newer version of docker mounts the cgroup memory limit/usage files directly under
 	// /sys/fs/cgroup/memory/ rather than /sys/fs/cgroup/memory/docker/$container_id/
-	if _, err := os.Stat(filepath.Join(CGROUP_FOLDER_PREFIX, path)); os.IsExist(err) {
+	if _, err := os.Stat(filepath.Join(CGROUP_FOLDER_PREFIX, path)); err == nil {
 		path = filepath.Join(CGROUP_FOLDER_PREFIX, path)
 	} else {
 		path = filepath.Join(CGROUP_FOLDER_PREFIX)