Design And Implemetation On DeskFS Journaling File System

Filesystem is an important part of modern operating system, and is expected to be both fast and exceedingly reliable. However, after an unexpected reboot, it may take some time for a system to recover its filesystem to a consistent state. As a newly developed technology, Journaling filesystem increase traditional filesystem's speed and availability of crash recovery by adding a transactional journal to the filesystem.However, there are a number of issues at journaling filesystem. Journaling block device is a simple and effective mode to implement the journaling technology, which still has some internal mechanism issues, such as the orphan files. Otherwise, the IOs which result from writing updates will affect the speed of the filesystem. So the performance should suffer seriously as the result of using the journaling filesystem.This thesis intends to design a suited journaling filesystem for an operating system which named"The multimedia official desktop Linux system".The thesis introduces the background of journaling filesystem, and shows some models and their features. Then it discusses main technology of the Linux filesystem: the virtual filesystem, the disk allocation and the orphan files problem.Further, the thesis compares the block allocation to the extent allocation, and presents a new way which named dynamic reserved block allocation to allocate disk. It is based on the extent allocation, and it realizes the thing that dynamic allocate disk in the memory. Further more, the paper solves the orphan files by judging the static state with a good effect.Finally, we design and implement the DeskFS journaling filesystem using the methods above, and test it. Experiments show that the DeskFS filesystem is better than the traditional filesystem.