OVL_COPY_FSX_FLAGS_MASK
BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON);
newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK;
newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK);