--- a/mm/filemap.c~mm-use-filemap_range_needs_writeback-for-o_direct-reads +++ a/mm/filemap.c @@ -2681,8 +2681,8 @@ generic_file_read_iter(struct kiocb *ioc size = i_size_read(inode); if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, iocb->ki_pos, - iocb->ki_pos + count - 1)) + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, + iocb->ki_pos + count - 1)) return -EAGAIN; } else { retval = filemap_write_and_wait_range(mapping,