superblock, the index node (or inode), the directory entry (or dentry), and finally, the file object are part of virtual file system (VFS) or virtual filesystem switch. The purpose of a VFS is to allow client applications to access different types of concrete file systems in a uniform way.
Relationships of major objects in the VFS
An Inode is a data structure on a Unix / Linux file system. An inode stores meta data about a regular file, directory, or other file system object. Inode acts as a interface between files and data. An inode can refer to a file or a directory or a symbolic link to another object. It contains a unique number (the i-number), the file's attributes, including name, date, size and read/write permissions, and a pointer to the file's location(not file name and file data). It is the counterpart to the FAT table in the DOS/Windows world.
Programs, services, texts, images, and so forth, are all files. Input and output devices, and generally all devices, are considered to be files, according to the system.
The superblock is the container for high-level metadata about a file system. The superblock is a structure that exists on disk (actually, multiple places on disk for redundancy) and also in memory. It provides the basis for dealing with the on-disk file system, as it defines the file system's managing parameters (for example, total number of blocks, free blocks, root index node).
Dentry is interface between files and Inodes. Dentries also play a role in directory caching which, ideally, keeps the most frequently used files on-hand for faster access.