[wip] improve mkfs, add CWD

inc/fs.h

@@ -14,6 +14,7 @@ struct fs_header {
 	unsigned int inode_ptrs[(FS_BLOCK_SIZE-sizeof(int)*3) / sizeof(int)];
 };
 
+__attribute__((packed))
 struct fs_header_extension {
 	unsigned int next_extension;
 	unsigned int inode_ptrs[(FS_BLOCK_SIZE-sizeof(int)) / sizeof(int)];
@@ -28,11 +29,20 @@ struct fs_inode {
 	unsigned int blocks[(FS_BLOCK_SIZE-sizeof(int)*3) / sizeof(int)];
 };
 
+__attribute__((packed))
 struct fs_inode_extension {
 	unsigned int next_extension;
 	unsigned int blocks[(FS_BLOCK_SIZE-sizeof(int)) / sizeof(int)];
 };
 
+__attribute__((packed))
+struct fs_directory_block_data {
+	unsigned char fname[60];
+	unsigned int inode_no;
+};
+
+char *fs_get_cwd(void);
+
 int fs_create(void *d);
 int fs_use(void *d);
 int fs_mkfs(void *d);