serve/mirror: Move some code tracking migration speed into serve

The rationale is that status will need this information

src/mirror.c

@@ -447,20 +447,6 @@ int mirror_exceeds_max_bps( struct mirror * mirror )
 	return 0;
 }
 
-/* Given historic bps measurements and number of bytes left to transfer, give
- * an estimate of how many seconds are remaining before the migration is
- * complete, assuming no new bytes are written.
- */
-uint64_t mirror_estimate_time( struct server * serve )
-{
-	uint64_t bytes_to_xfer =
-	  bitset_stream_size( serve->allocation_map ) +
-	  ( serve->size - serve->mirror->offset );
-
-	debug("Bytes left to transfer: %"PRIu64, bytes_to_xfer );
-	return bytes_to_xfer / ( mirror_current_bps( serve->mirror ) + 1 );
-}
-
 // ONLY CALL THIS AFTER CLOSING CLIENTS
 void mirror_complete( struct server *serve )
 {
@@ -622,7 +608,7 @@ static void mirror_read_cb( struct ev_loop *loop, ev_io *w, int revents )
 
 	/* Regardless of time estimates, if there's no waiting transfer, we can
 	 *  */
-	if ( !ctrl->clients_closed && ( !next_xfer || mirror_estimate_time( ctrl->serve ) < 60 ) ) {
+	if ( !ctrl->clients_closed && ( !next_xfer || server_mirror_eta( ctrl->serve ) < 60 ) ) {
 		info( "Closing clients to allow mirroring to converge" );
 		server_forbid_new_clients( ctrl->serve );
 		server_close_clients( ctrl->serve );

src/mirror.h

@@ -132,5 +132,7 @@ struct mirror_super * mirror_super_create(
 		);
 void * mirror_super_runner( void * serve_uncast );
 
+uint64_t mirror_current_bps( struct mirror * mirror );
+
 #endif
 

src/serve.c

@@ -860,6 +860,33 @@ int server_is_mirroring( struct server * serve )
 	return !!serve->mirror_super;
 }
 
+uint64_t server_mirror_bytes_remaining( struct server * serve )
+{
+	if ( server_is_mirroring( serve ) ) {
+		uint64_t bytes_to_xfer =
+			bitset_stream_size( serve->allocation_map ) +
+			( serve->size - serve->mirror->offset );
+
+		return bytes_to_xfer;
+	}
+
+	return 0;
+}
+
+/* Given historic bps measurements and number of bytes left to transfer, give
+ * an estimate of how many seconds are remaining before the migration is
+ * complete, assuming no new bytes are written.
+ */
+
+uint64_t server_mirror_eta( struct server * serve )
+{
+	if ( server_is_mirroring( serve ) ) {
+		uint64_t bytes_to_xfer = server_mirror_bytes_remaining( serve );
+		return bytes_to_xfer / ( mirror_current_bps( serve->mirror ) + 1 );
+	}
+
+	return 0;
+}
 
 void mirror_super_destroy( struct mirror_super * super );
 

src/serve.h

@@ -123,6 +123,10 @@ void server_unlock_acl( struct server *serve );
 void server_lock_start_mirror( struct server *serve );
 void server_unlock_start_mirror( struct server *serve );
 int server_is_mirroring( struct server * serve );
+
+uint64_t server_mirror_bytes_remaining( struct server * serve );
+uint64_t server_mirror_eta( struct server * serve );
+
 void server_abandon_mirror( struct server * serve );
 void server_prevent_mirror_start( struct server *serve );
 void server_allow_mirror_start( struct server *serve );