On Thu, Oct 3, 2024 at 12:00 AM Matthew Wilcox (Oracle) wrote:
>
> By implementing ->writepages instead of ->writepage, we remove a
> layer of indirect function calls from the writeback path and the
> last use of struct page in nilfs2.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> fs/nilfs2/mdt.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
> index ceb7dc0b5bad..4f4a935fcdc5 100644
> --- a/fs/nilfs2/mdt.c
> +++ b/fs/nilfs2/mdt.c
> @@ -396,10 +396,9 @@ int nilfs_mdt_fetch_dirty(struct inode *inode)
> return test_bit(NILFS_I_DIRTY, &ii->i_state);
> }
>
> -static int
> -nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
> +static int nilfs_mdt_write_folio(struct folio *folio,
> + struct writeback_control *wbc)
> {
> - struct folio *folio = page_folio(page);
> struct inode *inode = folio->mapping->host;
> struct super_block *sb;
> int err = 0;
> @@ -432,11 +431,23 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
> return err;
> }
>
> +static int nilfs_mdt_writeback(struct address_space *mapping,
> + struct writeback_control *wbc)
> +{
> + struct folio *folio = NULL;
> + int error;
> +
> + while ((folio = writeback_iter(mapping, wbc, folio, &error)))
> + nilfs_mdt_write_folio(folio, wbc);
In order to catch and return the error returned by
nilfs_mdt_write_folio, I think it's necessary to assign the return
value to the variable "error" in the loop as follows:
+ while ((folio = writeback_iter(mapping, wbc, folio, &error)))
+ error = nilfs_mdt_write_folio(folio, wbc);
> +
> + return error;
> +}
>
> static const struct address_space_operations def_mdt_aops = {
> .dirty_folio = block_dirty_folio,
> .invalidate_folio = block_invalidate_folio,
> - .writepage = nilfs_mdt_write_page,
> + .writepages = nilfs_mdt_writeback,
> + .migrate_folio = buffer_migrate_folio,
> };
And, this also caused kernel panics with the fsstress command. As
with patch 1/4, it was necessary to use buffer_migrate_folio_norefs
for migrate_folio:
+ .migrate_folio = buffer_migrate_folio_norefs,
Thanks,
Ryusuke Konishi
>
> static const struct inode_operations def_mdt_iops;
> --
> 2.43.0
>
