On Fri, May 10, 2024 at 12:29:02PM +0200, hare@xxxxxxxxxx wrote:
> +++ b/fs/mpage.c
> @@ -114,7 +114,7 @@ static void map_buffer_to_folio(struct folio *folio, struct buffer_head *bh,
> * don't make any buffers if there is only one buffer on
> * the folio and the folio just needs to be set up to date
> */
> - if (inode->i_blkbits == PAGE_SHIFT &&
> + if (inode->i_blkbits == folio_shift(folio) &&
yes
> @@ -160,7 +160,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> struct folio *folio = args->folio;
> struct inode *inode = folio->mapping->host;
> const unsigned blkbits = inode->i_blkbits;
> - const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
> + const unsigned blocks_per_folio = folio_size(folio) >> blkbits;
> const unsigned blocksize = 1 << blkbits;
> struct buffer_head *map_bh = &args->map_bh;
> sector_t block_in_file;
> @@ -168,7 +168,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> sector_t last_block_in_file;
> sector_t first_block;
> unsigned page_block;
> - unsigned first_hole = blocks_per_page;
> + unsigned first_hole = blocks_per_folio;
yes
> @@ -189,7 +189,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> goto confused;
>
> block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
> - last_block = block_in_file + args->nr_pages * blocks_per_page;
> + last_block = block_in_file + args->nr_pages * blocks_per_folio;
no. args->nr_pages really is the number of pages, so last_block is
block_in_file + nr_pages * blocks_per_page. except that blocks_per_page
might now be 0.
so i think this needs to be rewritten as:
last_block = block_in_file + (args->nr_pages * PAGE_SIZE) >> blkbits;
or have i confused myself?
> @@ -275,7 +275,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> bdev = map_bh->b_bdev;
> }
>
> - if (first_hole != blocks_per_page) {
> + if (first_hole != blocks_per_folio) {
> folio_zero_segment(folio, first_hole << blkbits, PAGE_SIZE);
... doesn't that need to be folio_size(folio)?
there may be other problems, but let's settle these questions first.
