nilfs2: remove calls to folio_set_error() and folio_clear_error()

Nobody checks this flag on nilfs2 folios, stop setting and clearing it. 
That lets us simplify nilfs_end_folio_io() slightly.

Link: https://lkml.kernel.org/r/20240420025029.2166544-17-willy@infradead.org
Link: https://lkml.kernel.org/r/20240430050901.3239-1-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Matthew Wilcox (Oracle)

fs/nilfs2/dir.c

@@ -174,7 +174,6 @@ static bool nilfs_check_folio(struct folio *folio, char *kaddr)
 		    dir->i_ino, (folio->index << PAGE_SHIFT) + offs,
 		    (unsigned long)le64_to_cpu(p->inode));
 fail:
-	folio_set_error(folio);
 	return false;
 }
 

fs/nilfs2/segment.c

@@ -1725,14 +1725,8 @@ static void nilfs_end_folio_io(struct folio *folio, int err)
 		return;
 	}
 
-	if (!err) {
-		if (!nilfs_folio_buffers_clean(folio))
-			filemap_dirty_folio(folio->mapping, folio);
-		folio_clear_error(folio);
-	} else {
+	if (err || !nilfs_folio_buffers_clean(folio))
 		filemap_dirty_folio(folio->mapping, folio);
-		folio_set_error(folio);
-	}
 
 	folio_end_writeback(folio);
 }