Re: [PATCH 2/2] gfs2: do not call gfs2_jdata_writepages for jdata

[Matthew Wilcox <willy@infradead.org>]

On Fri, Jun 06, 2025 at 05:47:56PM +0800, Su Yue wrote:
> +++ b/fs/gfs2/aops.c
> @@ -138,6 +138,46 @@ static int __gfs2_jdata_write_folio(struct folio *folio,
>  	return gfs2_write_jdata_full_folio(folio, wbc);
>  }
>  
> +/**
> + * gfs2_write_jdata_folio - Write folio
> + * @folio: folio to write
> + * @wbc: The writeback control
> + *
> + * Returns: errno
> + *
> + */
> +
> +static int gfs2_write_jdata_folio(struct folio *folio, struct writeback_control *wbc)
> +{
> +	struct inode *inode = folio->mapping->host;
> +	struct gfs2_inode *ip = GFS2_I(inode);
> +	struct gfs2_sbd *sdp = GFS2_SB(inode);
> +
> +	if (gfs2_assert_withdraw(sdp, ip->i_gl->gl_state == LM_ST_EXCLUSIVE))
> +		goto out;
> +	if (folio_test_checked(folio) || current->journal_info)
> +		goto out_ignore;
> +	return __gfs2_jdata_write_folio(folio, wbc);
> +
> +out_ignore:
> +	folio_redirty_for_writepage(wbc, folio);
> +out:
> +	folio_unlock(folio);
> +	return 0;
> +}
> +
> +int gfs2_write_jdata_folios(struct address_space *mapping, struct writeback_control *wbc)
> +{
> +	struct folio *folio = NULL;
> +	int error;
> +
> +	while ((folio = writeback_iter(mapping, wbc, folio, &error)))
> +		error = gfs2_write_jdata_folio(folio, wbc);
> +
> +	return error;
> +}

The great thing about using an iterator pattern rather than a callback
pattern is that we don't need this stupid extra function.  So you can
drop patch 1 and just do this:

+	struct inode *inode = mapping->host;
+	struct gfs2_inode *ip = GFS2_I(inode);
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
+
+	if (gfs2_assert_withdraw(sdp, ip->i_gl->gl_state == LM_ST_EXCLUSIVE))
+		return -Ewhatever;
+
+	while ((folio = writeback_iter(mapping, wbc, folio, &error))) {
+		if (folio_test_checked(folio) || current->journal_info)
+			goto ignore;
+		error = __gfs2_jdata_write_folio(folio, wbc);
+		continue;
+
+ignore:
+		folio_redirty_for_writepage(wbc, folio);
+		folio_unlock(folio);
+	}
+
+	return error;