Changes towards exit. Need to fix thread suspend first.

tasks/mm0/src/clone.c

@@ -105,7 +105,6 @@ int sys_fork(struct tcb *parent)
 	task_add_global(child);
 
 	/* Start forked child. */
-	printf("%s/%s: Starting forked child.\n", __TASKNAME__, __FUNCTION__);
 	l4_thread_control(THREAD_RUN, &ids);
 
 	/* Return child tid to parent */

tasks/mm0/src/file.c

@@ -371,13 +371,19 @@ int fsync_common(struct tcb *task, int fd)
 	int err;
 
 	/* Check fd validity */
+	if (fd < 0 || fd > TASK_FILES_MAX)
+		return -EINVAL;
+
+	/*
+	 * If we don't know about the file, even if it was
+	 * opened by the vfs, it is sure that there's no
+	 * pending IO on it. We simply return.
+	 */
 	if (!task->files->fd[fd].vmfile)
-		if ((err = file_open(task, fd)) < 0)
-			return err;
+		return 0;
 
 	/* Finish I/O on file */
-	BUG_ON(!(f = task->files->fd[fd].vmfile));
-	if ((err = flush_file_pages(f)) < 0)
+	if ((err = flush_file_pages(task->files->fd[fd].vmfile)) < 0)
 		return err;
 
 	return 0;

tasks/mm0/src/utcb.c

@@ -33,6 +33,11 @@ void *utcb_vaddr_new(void)
 	return address_new(&utcb_vaddr_pool, 1);
 }
 
+int utcb_vaddr_del(void *utcb_addr)
+{
+	return address_del(&utcb_vaddr_pool, utcb_addr, 1);
+}
+
 /*
  * Sends utcb address information to requester task, allocates
  * an address if it doesn't exist and the requester is asking