BDI_CAP_WRITE_MAP  258 include/linux/backing-dev.h 	(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
BDI_CAP_WRITE_MAP  265 include/linux/backing-dev.h 	 BDI_CAP_WRITE_MAP != VM_MAYWRITE || \