S3QL is a file system that stores all its data online. It supports Amazon S3, Google Storage, and OpenStack and effectively provides you with a hard disk of dynamic, infinite capacity that can be accessed from any computer with Internet access. S3QL provides a standard, full featured Unix file system that is conceptually indistinguishable from any local file system. Additional features include compression, encryption, data de-duplication, immutable trees, and snapshotting, which make it especially suitable for online backup and archiving. The design favors simplicity and elegance over performance and feature-creep. Care has been taken to make the source code as readable and serviceable as possible. Solid error detection, error handling, and extensive automated test cases are provided.
TOCC is a Tool for Obsessive Compulsive Classifiers. It implements a file system that uses tags instead of folders, allowing you to classify files however you want. For example, you could tag photos by location, people, and technique (e.g. black & white, HDR). Finding files is as simple as running a query like "give me all files tagged photo and my-love".
fstransform is a tool to change a file-system from one format to another. For example, it can change from jfs, xfs, or reiser to ext2, ext3, or ext4. It works in-place and without the need for backup. It currently has been tested on Linux only. It uses a sparse file to create the new file-system image, moves all the files of the existing file-system into it, then remaps the sparse file to the original partition.
Collectfs is an easy-to-use FUSE userspace filesystem that provides add-on trash collection for any Linux directory hierarchy. Any file that is overwritten by removal (unlinking), moving, linking, symlinking, or open-truncation is relocated to a trash directory (mount-point/.trash/). Removed files are date-time stamped so that edit history is maintained. (A version number is appended if the same file is collected more than once in the same second).
stegfs is a Fuse based file system which provides absolute security. Using encryption to secure files, and the art of steganography to hide them, stegfs aims to ensure that the existence of such files isn't guaranteed. Implemented as a Fuse based file system and using the mhash and mcrypt libraries to provide the cryptographic hash and symmetric block cipher functions, stegfs is at the cutting edge of secure file system technology.