Linux Filesystem Hierarchy(block)

superblock, inode, data block, directory block, and indirection block.

The superblock:
It contains information about the filesystem as a whole, such as its size (the exact information here depends on the filesystem).

An inode:
It contains all information about a file, except its name.

directory block: The name is stored in the directory,
together with the number of the inode. A directory entry consists of a filename and the number of the inode which represents the file.

data blocks
: The inode contains the numbers of several data blocks, which are used to store the data in the file.

indirection block
: There is space only for a few data block numbers in the inode, however, and if more are needed, more space for pointers to the data blocks is allocated dynamically. These dynamically allocated blocks are indirect blocks; the name
indicates that in order to find the data block, one has to find its number in the indirect block first.