NTFS: Fix a 64-bitness bug where a left-shift could overflow a 32-bit variable
      which we now cast to 64-bit first (fs/ntfs/mft.c::map_mft_record_page().

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 247586d..b011369 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -58,7 +58,8 @@
 	 * overflowing the unsigned long, but I don't think we would ever get
 	 * here if the volume was that big...
 	 */
-	index = ni->mft_no << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
+	index = (u64)ni->mft_no << vol->mft_record_size_bits >>
+			PAGE_CACHE_SHIFT;
 	ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
 
 	i_size = i_size_read(mft_vi);