Unionfs: call wait_on_page_writeback before clear_page_dirty_for_io

CC: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index 8c07eed40cbd4121c995df508043734619e5f23a..4d05352ed516811d20dc5c7bede56791586ff0c5 100644 (file)
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -72,8 +72,8 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
        }
 
        BUG_ON(!lower_mapping->a_ops->writepage);
-       clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
        wait_on_page_writeback(lower_page); /* prevent multiple writers */
+       clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
        err = lower_mapping->a_ops->writepage(lower_page, wbc);
        if (err < 0)
                goto out_release;