Custom Linux File System in C

Overview

Custom file system built in C using block-level I/O and a FAT-style volume, with full file and directory operation support via a shell interface.

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Features

• Custom volume format and initialization
• FAT-style free space management
• Directory entries with full metadata
• File Control Blocks with buffered read/write
• Persistent storage across runs
• Command-line shell with built-in commands

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Shell Commands

Supported commands:

• ls – list directory contents
• cd <dir> – change current directory
• md <dir> – make a new directory
• pwd – print current directory
• touch <file> – create an empty file
• cat <file> – display file contents
• rm <file> – delete a file
• cp <src> <dest> – copy a file
• mv <src> <dest> – move/rename a file
• cp2fs <host_file> – copy file from host into virtual file system
• cp2l <fs_file> – copy file from virtual file system to host
• help – list available commands

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Project Structure

- src/*.c     # C source files
- include/*.h # Header files
- obj/*.o     # Compiled object files
- Makefile    # Build script
- Dockerfile  # Docker image configuration

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Build & Run

git clone https://github.com/keyprocedure/linux-file-system.git
cd linux-file-system

Option 1: Using Docker:

# Build the Docker image
docker build -t linux-fs .

# Run the shell in a Docker container 
docker run -it -v $(pwd)/volume:/app/volume linux-fs

Option 2: Run Natively on Linux:

# Compile the system
make

# Launch the shell
make run    

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Technical Summary

Core Components

• VCB: Tracks volume info and root dir location
• FAT: Manages used/free blocks in a linked list style
• Directories: Support nested structures and metadata (., ..)
• Buffered I/O: Efficiently reads/writes to disk in blocks
• Persistence: All state is saved to a volume file between runs

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