mm: mark page accessed before we write_end()

In testing a backport of the write_begin/write_end AOPs, a 10% re-read
regression was noticed when running iozone.  This regression was
introduced because the old AOPs would always do a mark_page_accessed(page)
after the commit_write, but when the new AOPs where introduced, the only
place this was kept was in pagecache_write_end().

This patch does the same thing in the generic case as what is done in
pagecache_write_end(), which is just to mark the page accessed before we
do write_end().
Signed-off-by: NJosef Bacik <jbacik@redhat.com>
Acked-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

@@ -2272,6 +2272,7 @@ static ssize_t generic_perform_write(struct file *file,
 		pagefault_enable();
 		flush_dcache_page(page);
 
+		mark_page_accessed(page);
 		status = a_ops->write_end(file, mapping, pos, bytes, copied,
 						page, fsdata);
 		if (unlikely(status < 0))