[PATCH] D-cache aliasing issue in __block_prepare_write

A couple of flush_dcache_page()s are missing on the I/O-error paths.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/buffer.c

@@ -1854,6 +1854,7 @@ static int __block_prepare_write(struct inode *inode, struct page *page,
 			clear_buffer_new(bh);
 			kaddr = kmap_atomic(page, KM_USER0);
 			memset(kaddr+block_start, 0, bh->b_size);
+			flush_dcache_page(page);
 			kunmap_atomic(kaddr, KM_USER0);
 			set_buffer_uptodate(bh);
 			mark_buffer_dirty(bh);
@@ -2360,6 +2361,7 @@ int nobh_prepare_write(struct page *page, unsigned from, unsigned to,
 	 */
 	kaddr = kmap_atomic(page, KM_USER0);
 	memset(kaddr, 0, PAGE_CACHE_SIZE);
+	flush_dcache_page(page);
 	kunmap_atomic(kaddr, KM_USER0);
 	SetPageUptodate(page);
 	set_page_dirty(page);