Research And Implementation Of Namespace Management For SpaceFS

This topic is the subsequent development of the SpaceFS file system developed by Beijing Jinjie scientific and technological Institute.In light of the exsiting issues about the security and reliability of computer operating system secure and reliable,SpaceFS is developed,the main principle is - limit OS physical storage space,and it can not be rewritten.Will be relatively independent of the operating system installed in the physical space,and other applications software in the physical separation of space,the operating system will be installed into a physical storage medium limited to read-only,so that the operating system installed can not be rewritten on the physical layer, so as to achieve secure and reliable;at the same time,user space and system space isolated from each other in the physical space,when users need to install software or preserve documents,can be transparent in the storage space. This topic is expected to solve several issues in the SpaceFS and improve the whole efficiency.In order to inter-communicate with other file systems which are compliant to the POSIX standard like NFS, SpaceFS has to store much extra information.Being virtual file system,SpaceFS needs to create and maintain a lot of meta data in the memory,or it will cost too many resources to rebuild these information during system boot up. So,the whole performance of SpaceFS will be highly improved if these information can be stored persistently.Also, the exsiting mechanisms of mapping of inode number and hard link management need to be consummated.For the above reasons,State Maintainer(SM) is introduced,briefly,with the assistance of State Maintainer,SpaceFS can create whiteout,opgque file for directory and directory caches on the separate partition or loopback device,to solve the issues mentioned above.This paper first describes the design framework and work mechanisms of SpaceFS,and analyses in details what issues the State Maintainer focuses on and its design principles;then gives very detailed comments of the most important interfaces;at last,very strict tests are done on all of the interface functions,and provides related test journals.The study has helped SpaceFS which is already used in practice to solve several important issues like namespace polluting,mapping of inode number and hard link management,thus improves the whole performance of SpaceFS and makes it possible for the expansibility of SpaceFS...