cifs: have cifs parse scope_id out of IPv6 addresses and use it

This patch has CIFS look for a '%' in an IPv6 address. If one is
present then it will try to treat that value as a numeric interface
index suitable for stuffing into the sin6_scope_id field.

This should allow people to mount servers on IPv6 link-local addresses.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: David Holder <david@erion.co.uk>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c368ad6..3fb799f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1386,8 +1386,10 @@
 		     server->addr.sockAddr.sin_addr.s_addr))
 			continue;
 		else if (addr->ss_family == AF_INET6 &&
-			 !ipv6_addr_equal(&server->addr.sockAddr6.sin6_addr,
-					  &addr6->sin6_addr))
+			 (!ipv6_addr_equal(&server->addr.sockAddr6.sin6_addr,
+					   &addr6->sin6_addr) ||
+			  server->addr.sockAddr6.sin6_scope_id !=
+					   addr6->sin6_scope_id))
 			continue;
 
 		++server->srv_count;