The main goal for this report is to provide an introduction to metadata file systems, and some information on how file systems are implemented in the Linux kernel version 2.6. Reading this report you will find answers to questions such as what a metadata is, what a metadata file system is, what are the advantages and disadvantages of a metadata file system. The report will also provide a very simple proposal, and the beginning of a metadata file system implementation. Because of the main goal of the report is to give an introduction to metadata file systems, the introduction chapter is going to be a big part of the project, while the other parts such as design and implementation will primary contain my ideas to how a metadata file system could be designed and implemented. This report will not contain any information or guides how to install or setup a metadata file system on your personal computer. Neither will cover metadata search system (such as Strigi[17], Beagle[18], Gnome storage[16] or Spotlight[19]) as they are not based on a metadata file system, but only on indexing the metadata in the files.