[Understanding The Linux Kernel]

The common file model consists of the following object types:

• The superblock object Stores information concerning a mounted filesystem. For disk-based filesystems, this object usually corresponds to a filesystem control block stored on disk.

• The inode object Stores general information about a specific file. For disk-based filesystems, this object usually corresponds to a file control block stored on disk. Each inode object is associated with an inode number, which uniquely identifies the file within the filesystem.

dentry Objects

The kernel creates a dentry object for every component of a pathname that a process looks up; the dentry object associates the component to its corresponding inode. For example, when looking up the /tmp/test pathname, the kernel creates

• a dentry object for the / root directory,

• a second dentry object for the tmp entry of the root directory,

• and a third dentry object for the test entry of the /tmp directory.