VFS updates, readme updates.

Separated vfs file as a specific file. vm file is not always a vfs file.
Updated the README
sys_open was not returning back to client, added that.
Added comments for future vfs additions.

tasks/mm0/include/file.h

@@ -2,6 +2,7 @@
 #define __MM0_FILE_H__
 
 #include <l4/lib/list.h>
+#include <l4lib/types.h>
 #include <posix/sys/types.h>
 
 void vmfile_init(void);
@@ -17,6 +18,15 @@ int sys_read(l4id_t sender, int fd, void *buf, int count);
 int sys_write(l4id_t sender, int fd, void *buf, int count);
 int sys_lseek(l4id_t sender, int fd, off_t offset, int whence);
 
-#define vm_file_to_vnum(f)	(*(unsigned long *)((f)->priv_data))
+struct vfs_file_data {
+	unsigned long vnum;
+};
+
+#define vm_file_to_vnum(f)	\
+	(((struct vfs_file_data *)((f)->priv_data))->vnum)
+struct vm_file *vfs_file_create(void);
+
+
 extern struct list_head vm_file_list;
+
 #endif /* __MM0_FILE_H__ */

tasks/mm0/include/vm_area.h

@@ -40,7 +40,7 @@
 /* Defines the type of file. A device file? Regular file? One used at boot? */
 enum VM_FILE_TYPE {
 	VM_FILE_DEVZERO = 1,
-	VM_FILE_REGULAR,
+	VM_FILE_VFS,
 	VM_FILE_BOOTFILE,
 	VM_FILE_SHM,
 };