From: NeilBrown <neilb@suse.de>

When we update a page_cache page in the kernel, we need to flush_dache_page or
userspace might not see the change.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/md/bitmap.c |    2 ++
 1 files changed, 2 insertions(+)

diff -puN drivers/md/bitmap.c~md-make-sure-bitmap-updates-are-visible-through-filesystem drivers/md/bitmap.c
--- devel/drivers/md/bitmap.c~md-make-sure-bitmap-updates-are-visible-through-filesystem	2005-12-12 02:04:15.000000000 -0800
+++ devel-akpm/drivers/md/bitmap.c	2005-12-12 02:04:15.000000000 -0800
@@ -315,6 +315,8 @@ static int write_page(struct bitmap *bit
 	if (bitmap->file == NULL)
 		return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
 
+	flush_dcache_page(page); /* make sure visible to anyone reading the file */
+
 	if (wait)
 		lock_page(page);
 	else {
_