[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>