litfs

This FUSE filesystem, apart from providing the normal file I/O operations, implements persistence by emulating a single binary Unix file as disk and performing read/writes on it.

Build and Run

go get github.com/anaskhan96/litfs
cd $GOPATH/src/github.com/anaskhan96/litfs
go run main.go data # data/ is the directory on which to mount the filesystem on

Run umount <path-to-directory> to unmount the filesystem.

File System Characteristics

• Create, remove a directory
• Create, remove, read from, and write to files inside a directory
• Copy, move the contents of a file to another, across directories

Persistence Implementation

disklib/sda is the created binary file emulating a disk. Keeping a block size of 4096 bytes:

• A serialized form of the tree representation of the filesystem is stored in the first block
• A structure containing two components - a bitmap indicating free and allocated blocks in the filesystem and an integer containing the lowest free block at the moment - is serialized and stored in the second block
• File data is stored from the third block onwards, with a block as a whole being allocated to/deallocated from the file

This project was built under the course Unix Systems Programming at PES University.