ifs_alloc
ifs = ifs_alloc(inode, folio, 0);
ifs_alloc(iter->inode, folio, iter->flags);
ifs = ifs_alloc(iter->inode, folio, iter->flags);
ifs_alloc(inode, folio, 0);
ifs = ifs_alloc(iter->inode, folio, iter->flags);