Linux Filesystem Internals
The Linux filesystem layer is where your code meets the hardware. Understanding how VFS, inodes, dentries, and mount points work explains why Linux can mount ext4, btrfs, NFS, and tmpfs through a single unified API.
What This Section Covers
Dive deep into how Linux manages files at the kernel level:
- Virtual Filesystem (VFS) — the abstraction layer that makes all filesystems look the same
- Inodes Explained — the data structures that track every file
- File Systems Overview — ext4, btrfs, xfs, tmpfs compared
- Hard Links vs Soft Links — how the kernel resolves paths
The Virtual Filesystem Layer
Why can Linux read ext4, NTFS, NFS, and /proc through the same open() call?
The Virtual Filesystem (VFS) is a kernel abstraction layer that defines a common interface. Every filesystem driver implements the same set of function pointers (open, read, write, lookup, etc.). Your program calls open() → VFS routes it to the right filesystem driver → driver does the real work. Your code never knows which filesystem it's talking to.