fs: switch ->s_uuid to uuid_t

For some file systems we still memcpy into it, but in various places this
already allows us to use the proper uuid helpers.  More to come..

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/include/linux/cleancache.h b/include/linux/cleancache.h
index fccf7f4..bbb3712 100644
--- a/include/linux/cleancache.h
+++ b/include/linux/cleancache.h
@@ -27,7 +27,7 @@ struct cleancache_filekey {
 
 struct cleancache_ops {
 	int (*init_fs)(size_t);
-	int (*init_shared_fs)(char *uuid, size_t);
+	int (*init_shared_fs)(uuid_t *uuid, size_t);
 	int (*get_page)(int, struct cleancache_filekey,
 			pgoff_t, struct page *);
 	void (*put_page)(int, struct cleancache_filekey,