On Thu 21-09-23 21:07:39, Matthew Wilcox (Oracle) wrote:
> Support in this function for large folios is limited to supporting
> filesystems with block size > PAGE_SIZE. This new functionality will only
> be supported on machines without HIGHMEM, so the problem of kmap_local
> only being able to map a single page in the folio can be ignored.
> We will not use large folios for ext2 directories on HIGHMEM machines.
OK, but can we perhaps enforce this with some checks & error messages
instead of a silent failure? Like:
#ifdef CONFIG_HIGHMEM
if (sb->s_blocksize > PAGE_SIZE)
bail with error
#endif
somewhere in ext2_fill_super()? Or maybe force allocation of lowmem pages
when blocksize > PAGE_SIZE?
Honza
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> fs/ext2/dir.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
> index b335f17f682f..03867381eec2 100644
> --- a/fs/ext2/dir.c
> +++ b/fs/ext2/dir.c
> @@ -96,19 +96,19 @@ static void ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
> unlock_page(page);
> }
>
> -static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
> +static bool ext2_check_folio(struct folio *folio, int quiet, char *kaddr)
> {
> - struct inode *dir = page->mapping->host;
> + struct inode *dir = folio->mapping->host;
> struct super_block *sb = dir->i_sb;
> unsigned chunk_size = ext2_chunk_size(dir);
> u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
> unsigned offs, rec_len;
> - unsigned limit = PAGE_SIZE;
> + unsigned limit = folio_size(folio);
> ext2_dirent *p;
> char *error;
>
> - if ((dir->i_size >> PAGE_SHIFT) == page->index) {
> - limit = dir->i_size & ~PAGE_MASK;
> + if (dir->i_size < folio_pos(folio) + limit) {
> + limit = offset_in_folio(folio, dir->i_size);
> if (limit & (chunk_size - 1))
> goto Ebadsize;
> if (!limit)
> @@ -132,7 +132,7 @@ static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
> if (offs != limit)
> goto Eend;
> out:
> - SetPageChecked(page);
> + folio_set_checked(folio);
> return true;
>
> /* Too bad, we had an error */
> @@ -160,22 +160,22 @@ static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
> bad_entry:
> if (!quiet)
> ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
> - "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
> - dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
> + "offset=%llu, inode=%lu, rec_len=%d, name_len=%d",
> + dir->i_ino, error, folio_pos(folio) + offs,
> (unsigned long) le32_to_cpu(p->inode),
> rec_len, p->name_len);
> goto fail;
> Eend:
> if (!quiet) {
> p = (ext2_dirent *)(kaddr + offs);
> - ext2_error(sb, "ext2_check_page",
> + ext2_error(sb, "ext2_check_folio",
> "entry in directory #%lu spans the page boundary"
> - "offset=%lu, inode=%lu",
> - dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
> + "offset=%llu, inode=%lu",
> + dir->i_ino, folio_pos(folio) + offs,
> (unsigned long) le32_to_cpu(p->inode));
> }
> fail:
> - SetPageError(page);
> + folio_set_error(folio);
> return false;
> }
>
> @@ -195,9 +195,9 @@ static void *ext2_get_page(struct inode *dir, unsigned long n,
>
> if (IS_ERR(folio))
> return ERR_CAST(folio);
> - page_addr = kmap_local_folio(folio, n & (folio_nr_pages(folio) - 1));
> + page_addr = kmap_local_folio(folio, 0);
> if (unlikely(!folio_test_checked(folio))) {
> - if (!ext2_check_page(&folio->page, quiet, page_addr))
> + if (!ext2_check_folio(folio, quiet, page_addr))
> goto fail;
> }
> *page = &folio->page;
> --
> 2.40.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
