On Mon 18-12-23 16:35:39, Christoph Hellwig wrote:
> Rework we deal with the cleanup after the writepage call. First handle
^^ the way
> the magic AOP_WRITEPAGE_ACTIVATE separately from real error returns to
> get it out of the way of the actual error handling. Then merge the
> code to set ret for integrity vs non-integrity writeback. For
> non-integrity writeback the loop is terminated on the first error, so
> ret will never be non-zero. Then use a single block to check for
> non-integrity writewack to consolidate the cases where it returns for
> either an error or running off the end of nr_to_write.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Otherwise looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> mm/page-writeback.c | 62 +++++++++++++++++++++------------------------
> 1 file changed, 29 insertions(+), 33 deletions(-)
>
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 8e312d73475646..7ed6c2bc8dd51c 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2474,43 +2474,39 @@ int write_cache_pages(struct address_space *mapping,
> error = writepage(folio, wbc, data);
> nr = folio_nr_pages(folio);
> wbc->nr_to_write -= nr;
> - if (unlikely(error)) {
> - /*
> - * Handle errors according to the type of
> - * writeback. There's no need to continue for
> - * background writeback. Just push done_index
> - * past this page so media errors won't choke
> - * writeout for the entire file. For integrity
> - * writeback, we must process the entire dirty
> - * set regardless of errors because the fs may
> - * still have state to clear for each page. In
> - * that case we continue processing and return
> - * the first error.
> - */
> - if (error == AOP_WRITEPAGE_ACTIVATE) {
> - folio_unlock(folio);
> - error = 0;
> - } else if (wbc->sync_mode != WB_SYNC_ALL) {
> - ret = error;
> - done_index = folio->index + nr;
> - done = 1;
> - break;
> - }
> - if (!ret)
> - ret = error;
> +
> + /*
> + * Handle the legacy AOP_WRITEPAGE_ACTIVATE magic return
> + * value. Eventually all instances should just unlock
> + * the folio themselves and return 0;
> + */
> + if (error == AOP_WRITEPAGE_ACTIVATE) {
> + folio_unlock(folio);
> + error = 0;
> }
>
> /*
> - * We stop writing back only if we are not doing
> - * integrity sync. In case of integrity sync we have to
> - * keep going until we have written all the pages
> - * we tagged for writeback prior to entering this loop.
> + * For integrity sync we have to keep going until we
> + * have written all the folios we tagged for writeback
> + * prior to entering this loop, even if we run past
> + * wbc->nr_to_write or encounter errors. This is
> + * because the file system may still have state to clear
> + * for each folio. We'll eventually return the first
> + * error encountered.
> + *
> + * For background writeback just push done_index past
> + * this folio so that we can just restart where we left
> + * off and media errors won't choke writeout for the
> + * entire file.
> */
> - done_index = folio->index + nr;
> - if (wbc->nr_to_write <= 0 &&
> - wbc->sync_mode == WB_SYNC_NONE) {
> - done = 1;
> - break;
> + if (error && !ret)
> + ret = error;
> + if (wbc->sync_mode == WB_SYNC_NONE) {
> + if (ret || wbc->nr_to_write <= 0) {
> + done_index = folio->index + nr;
> + done = 1;
> + break;
> + }
> }
> }
> folio_batch_release(&fbatch);
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
