OVL_COPY_I_FLAGS_MASK
flags = ovl_inode_real(inode)->i_flags & OVL_COPY_I_FLAGS_MASK;
BUILD_BUG_ON(OVL_PROT_I_FLAGS_MASK & ~OVL_COPY_I_FLAGS_MASK);
inode_set_flags(inode, flags, OVL_COPY_I_FLAGS_MASK);
unsigned int mask = OVL_COPY_I_FLAGS_MASK;