File objects – representing open files
Similar to dentry objects, file objects are an in-memory representation of open files. The file object represents a process’s view of an open file. Like dentry objects, file objects also do not correspond to any on-disk structures. When we covered system calls in Chapter 1, it was mentioned that the user-space programs interact with VFS through the system call interface. These system calls are generic functions for performing common operations such as read and write. The idea behind all this is to ensure that user-space programs don’t have to worry about filesystems and their data structures.
When applications generate a system call to access a file, such as open (), a file object gets created in memory. Similarly, when the application no longer needs access to the file and decides to close it using close (), the file object is discarded. It’s important to note that VFS can create multiple file objects for a particular...
