Original Unix filesystems were composed of 3 main areas:
The superblock is a data structure at the beginning of the filesystem, and takes up 1 filesystem block. The superblock contains status information about the filesystem such as the filesystem block size, the number of free blocks and the mount status.
The inode list, also known as the inode table, contains data structures that provide information about files.
The datablock area contains actual file data, as well as directory files, which are filesystem metadata.
 Filesystem metadata is all the data saved on the filesystem that does not belong to real files. that is, data that no user intentionally wanted to save as being a part of any file, however it is required for the management of the filesystem.Superblocks, inodes and directory files are examples of filesystem metadata.