[PATCH] NTFS: Critical bug fix (affects MIPS and possibly others)

It fixes a crash in NTFS on architectures where flush_dcache_page()
is a real function.  I never noticed this as all my testing is done on
i386 where flush_dcache_page() is NULL.

http://bugzilla.kernel.org/show_bug.cgi?id=6700

Many thanks to Pauline Ng for the detailed bug report and analysis!
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

fs/ntfs/file.c

@@ -1489,14 +1489,15 @@ static inline void ntfs_flush_dcache_pages(struct page **pages,
 		unsigned nr_pages)
 {
 	BUG_ON(!nr_pages);
+	/*
+	 * Warning: Do not do the decrement at the same time as the call to
+	 * flush_dcache_page() because it is a NULL macro on i386 and hence the
+	 * decrement never happens so the loop never terminates.
+	 */
 	do {
-		/*
-		 * Warning: Do not do the decrement at the same time as the
-		 * call because flush_dcache_page() is a NULL macro on i386
-		 * and hence the decrement never happens.
-		 */
+		--nr_pages;
 		flush_dcache_page(pages[nr_pages]);
-	} while (--nr_pages > 0);
+	} while (nr_pages > 0);
 }
 
 /**