NFS support for BtrFS

For the uninitiated, Btrfs is a new copy on write filesystem for Linux aimed at implementing advanced features while focusing on fault tolerance, repair and easy administration. Initially developed by Oracle, Btrfs is licensed under the GPL and open for contribution from anyone. My interest in it lies in BtrFS being a very good competitor to the much talked of Sun ZFS. It has got a bunch of features like, (Taken from Btrfs wiki).

• Extent based file storage (2^64 max file size)
• Space efficient packing of small files
• Space efficient indexed directories
• Dynamic inode allocation
• Writable snapshots
• Subvolumes (separate internal filesystem roots)
• Object level mirroring and striping
• Checksums on data and metadata (multiple algorithms available)
• Strong integration with device mapper for multiple device support
• Online filesystem check
• Very fast offline filesystem check
• Efficient incremental backup and FS mirroring

After having decided to write NFS support for BtrFS today 24 hours ago,  I’ve come up with an initial version of the implementation. It works mostly, but its not perfect. I’m sure I have messed up some locking stuff. Let me see what the devs at btrfs devel have to say.

You can find the RFC patch here. I just hope it gets into BtrFS in a couple of iterations.