Ext3 File System Structure And The Implementation Of Intrusion Detection

A filesystem is the software used to organize and manage the data stored on disk drives; it ensures the integrity of the data, ie data written to disk is identical with that when it is read back. In addition to storing the data contained in files, a filesystem also stores and manages important information about the files and about the filesystem itself (i.e. date and time stamps, ownership, access permissions, the file's size and the storage location or locations on disk, and so on). This information is commonly referred to as metadata. So it is very clear that filesystem is one of the most important components to operating systems. The design of the organizational framework for a filesystem determines the performance of the whole operating system. In this paper, I analyze the structure and performance of Ext3 filesystem supported by Linux, especially the JBD (Journal Block Device Layer) mechanism the Ext3 filesystem used to achieve the journaling function for the fielsystem. By this way, I explain the working process of JBD and its main data structure, as well as the solutions to the problems still existed in the Ext3 filesystem. In the meantime, I make in-depth research on some of the security measures for filesystem, and achieve the security checks for some of the leaks in the filesystem.