UBIFS: add inode size debugging check

Add one more check to UBIFS - a check that makes sure that there
are no data nodes beyond inode size. And few commantaries fixes
along the line.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Adrian Hunter <Adrian.Hunter@nokia.com>

fs/ubifs/super.c

@@ -317,6 +317,8 @@ static int ubifs_write_inode(struct inode *inode, int wait)
 		if (err)
 			ubifs_err("can't write inode %lu, error %d",
 				  inode->i_ino, err);
+		else
+			err = dbg_check_inode_size(c, inode, ui->ui_size);
 	}
 
 	ui->dirty = 0;