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/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index d7f282d..1d32cd2 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -164,7 +164,7 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
 	hmac_misc.mode = inode->i_mode;
 	crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc));
 	if (evm_hmac_attrs & EVM_ATTR_FSUUID)
-		crypto_shash_update(desc, inode->i_sb->s_uuid,
+		crypto_shash_update(desc, &inode->i_sb->s_uuid.b[0],
 				    sizeof(inode->i_sb->s_uuid));
 	crypto_shash_final(desc, digest);
 }