> > +setup_zeroed_file() > > +{ > > + local file_len=$1 > > + local sparse=$2 > > + > > + if $sparse; then > > + $XFS_IO_PROG -f -c "truncate $file_len" $test_file > > + else > > + $XFS_IO_PROG -f -c "falloc 0 $file_len" $test_file > > + fi > > +} > > + > > +round_up_to_page_boundary() > > +{ > > + local n=$1 > > + local page_size=$(_get_page_size) > > + > > + echo $(( (n + page_size - 1) & ~(page_size - 1) )) > > Does iomap put a large folio into the pagecache that crosses EOF, or > does it back down to base page size? No, we back it down to the base page size if the higher order folio crosses EOF. But this changes when we have the LBS support as we need to guarantee the base folio order that will be based on the filesystem BS.