This project implements a version of the Very Simple File System (VSFS) using the FUSE (Filesystem in Userspace) library. The goal of the project was to provide functionality for creating, reading, writing, deleting, and resizing files on a disk image. This assignment showcases a strong understanding of file system architecture, low-level systems programming, and the FUSE API.
- File System Creation: Supports the creation of an empty VSFS disk image.
- Basic File Operations: Implements file creation, deletion, reading, writing, and resizing.
- Directory Operations: Lists files and retrieves status information about the file system.
- Error Handling: Includes robust error handling to maintain system stability and data consistency.
- C Programming Language: Main implementation language.
- FUSE Library: Used to create the file system in user space.
- Linux Environment: Developed and tested on a Linux system.
/project-directory │── mkfs.c # Code for formatting an empty disk into a VSFS file system │── vsfs.c # Main file containing FUSE callbacks for file system operations │── vsfs.h # Header file containing data structures and constants for VSFS │── map.c # Helper functions for mapping the disk image file into memory │── map.h # Header file for the map.c functions │── fs_ctx.c # Contains runtime state management of the mounted file system │── fs_ctx.h # Header file for fs_ctx.c │── util.h # Utility functions to assist with operations such as bit manipulation │── bitmap.c # Functions to manage bitmaps for block and inode allocation │── bitmap.h # Header file for bitmap.c │── Makefile # Compilation instructions │── README.md # This documentation file
To compile the project, use the provided Makefile. Run the following command in the terminal:
makeThis command will generate two executables:
mkfs.vsfs: Used for formatting an empty disk image. vsfs: Used to run and mount the VSFS using FUSE.
To create an empty disk image, use the truncate command and mkfs.vsfs executable:
bash
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truncate -s <size> <image_file>
./mkfs.vsfs -i <number_of_inodes> <image_file>
Replace with the desired size of the image (e.g., 64K or 1M). Replace <number_of_inodes> with the total number of inodes for the file system.
To mount the VSFS on a specific mount point:
bash
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mkdir /tmp/<username>
./vsfs <image_file> /tmp/<username> -f
Replace <image_file> with the name of your disk image. Replace with your username or a directory of your choice.
After mounting, you can use standard file operations like ls, cp, rm, etc., to interact with the mounted file system.
To unmount the file system, use:
bash
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fusermount -u /tmp/<username>
Testing
To verify the implementation, you can run operations like:
ls -l to list files and directories.
touch to create files.
echo "data" > file.txt to write data into a file.
cat file.txt to read file contents.
rm file.txt to delete a file.
Provided Consistency Checkers
Two consistency checkers (fsck.mkfs and fsck.vsfs) are provided in the course repository to test the correctness of your file system:
fsck.mkfs: Checks that mkfs.vsfs correctly formats the disk. fsck.vsfs: Checks for data consistency and ensures that file system operations do not corrupt the disk. Challenges and Learning Outcomes
File System Architecture: Gained hands-on experience with implementing a file system's core functionalities, including block allocation, inode management, and data handling. Error Handling: Implemented robust error handling to ensure system stability and data integrity. FUSE Library: Learned how to interact with the FUSE library to implement a file system in user space.
libfuse GitHub Repository
FUSE API Documentation
OSTEP Textbook: Referenced for understanding the VSFS structure.
Aryaman Arora, University of Toronto, CSC369 - Fall 2023