writeback: writeback_inodes_sb() should use bdi_start_writeback()

Pointless to iterate other devices looking for a super, when
we have a bdi mapping.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 52aa54540079ca09ac5547c1a668afb5edb6fcb4..fb61178c86e3e56eb0dcecaad7ff6e3f3db1cc1d 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1206,7 +1206,7 @@ void writeback_inodes_sb(struct super_block *sb)
        nr_to_write = nr_dirty + nr_unstable +
                        (inodes_stat.nr_inodes - inodes_stat.nr_unused);
 
-       bdi_writeback_all(sb, nr_to_write);
+       bdi_start_writeback(sb->s_bdi, nr_to_write);
 }
 EXPORT_SYMBOL(writeback_inodes_sb);