Planned Extensions to the Linux Ext2/Ext3 Filesystem

The ext2 filesystem was designed with the goal of expandability while maintaining compatibility. This paper describes ways in which advanced filesystem features can be added to the ext2 filesystem while retaining forwards and backwards compatibility as much as possible. Some of the filesystem extensions that are discussed include directory indexing, online resizing, an expanded inode, extended attributes and access control lists support, extensible inode tables, extent maps, and preallocation.