flexnbd status: Add current migration pass to the status output if we're migrating

src/mirror.c

@@ -347,13 +347,14 @@ void mirror_run( struct server *serve )
 	NULLCHECK( serve );
 	NULLCHECK( serve->mirror );
 
-	int pass;
+	struct mirror* m = serve->mirror;
+
 	uint64_t written;
 
 	info("Starting mirror" );
-	for (pass=0; pass < mirror_maximum_passes-1; pass++) {
+	for (m->pass=0; m->pass < mirror_maximum_passes-1; m->pass++) {
 
-		debug("mirror start pass=%d", pass);
+		debug("mirror start pass=%d", m->pass);
 		if ( !mirror_pass( serve, 0, &written ) ){
 			debug("Failed mirror pass state is %d", mirror_get_state( serve->mirror ) );
 			debug("pass failed, giving up");

src/mirror.h

@@ -69,7 +69,7 @@ struct mirror {
 	const char *         filename;
 	off64_t              max_bytes_per_second;
 	enum mirror_finish_action action_at_finish;
-	
+
 	char                 *mapped;
 	struct bitset_mapping *dirty_map;
 
@@ -79,6 +79,9 @@ struct mirror {
 	 * and checking the remote size, whether successful or not.
 	 */
 	struct mbox *        commit_signal;
+
+	/* The current mirror pass. We put this here so status can query it */
+	int pass;
 };
 
 
@@ -106,3 +109,4 @@ struct mirror_super * mirror_super_create(
 		);
 void * mirror_super_runner( void * serve_uncast );
 #endif
+

src/status.c

@@ -11,6 +11,11 @@ struct status * status_create( struct server * serve )
 	status->pid = getpid();
 	status->has_control = serve->success;
 	status->is_mirroring = NULL != serve->mirror;
+
+	if ( status->is_mirroring ) {
+		status->migration_pass = serve->mirror->pass;
+	}
+
 	return status;
 
 }
@@ -26,6 +31,11 @@ int status_write( struct status * status, int fd )
 	PRINT_INT( pid );
 	PRINT_BOOL( is_mirroring );
 	PRINT_BOOL( has_control );
+
+	if ( status->is_mirroring ) {
+		PRINT_INT( migration_pass );
+	}
+
 	dprintf(fd, "\n");
 	return 1;
 }
@@ -36,3 +46,4 @@ void status_destroy( struct status * status )
 	NULLCHECK( status );
 	free( status );
 }
+

src/status.h

@@ -32,8 +32,17 @@
  * 	or "serve" mode.  It will become true when a server in "serve"
  * 	mode starts a migration, and will become false again when the
  * 	migration terminates, successfully or not.
- *	If the server is currently in "listen" mode, this will never b
+ *	If the server is currently in "listen" mode, this will never be
  *	true.
+ *
+ * If is_migrating is true, then a number of other attributes may appear,
+ * relating to the progress of the migration.
+ *
+ * migration_pass:
+ *  When migrating, we perform a number of passes over the file. This indicates
+ *  the current pass.
+ *
+ *
  */
 
 
@@ -46,6 +55,7 @@ struct status {
 	pid_t pid;
 	int has_control;
 	int is_mirroring;
+	int migration_pass;
 };
 
 /** Create a status object for the given server. */
@@ -60,3 +70,4 @@ void status_destroy( struct status * );
 
 
 #endif
+