Btrfs (B-tree filesystem) is a filesystem uses Btrees as its main on-disk data structure. It is based on Copy-on-Write (CoW) principle which means it does copy only when a write request is sent or a modification is necessary. Btree is used most in filesystem, database system. In Haiku, Btrfs is currently support read-only, the codebase only shows the basic structure, read operations, it lacks of core tree manipulation code, write supports, and other features. The project ideas request supporting write features for Btrfs. This will be accomplished in the following steps: Setting up userland friendly development mode for Btrfs, implementing tree operations (splittings, CoW, etc), adding more Btrfs structures if necessary, implementing write-feature functions.