Hey buddy, its a good work. You never know how many people you end up helping with this code. I would definitely recommend this as a starter. One recommendation: add support for page-cache. Start with read-cache only, and then mmap support, you need that to allow binary execution. -Rajat On Tue, Aug 6, 2013 at 12:27 AM, Sankar P <sankar.curiosity@xxxxxxxxx> wrote: > Hi, > > For learning purposes, I thought I would implement a filesystem from > the scratch. It has reached a state where I can do a 1.0 release. > > The sources are at: https://github.com/psankar/simplefs > > The layout is simple. The first (zeroth) block is the superblock and > contains information like fs magic, number of inodes, freeblock map > etc. The next block is the inode store. Creation of files and > directories is supported. Nested directories are supported. A file can > grow up to one block only. The data blocks for a directory contain the > filename and inode number of its children. For files, it will > obviously contain the actual data of the file. There are three > rudimentary locks to make sure the accesses are thread safe. > > The 1.0 version is filled with a lot of TODOs and memory leaks. Also > while implementing this, I realized that it is a bad idea to maintain > the superblock and the freeblock store together in a block. So I am > planning to change the on-disk layout in the next version. > > Apart from moving the super block to minimize locks, I am planning to > implement support for extents in the next version, and journalling in > the next-to-next version. The next version will take some time to > come, though. But if someone wants to try filesystems from the > scratch, I thought it may be useful if I share the link now itself. > > Also, I take this moment to thank the kernelnewbies list, especially > the regular people like Mulyadi Santosa, Valdis Kletnieks, Rajat > Sharma, Greg Freemyer etc. Also I would like to thank Neha Naik, > Manish Katiyar who helped me with some queries during this particular > implementation. I saw that Manish Katiyar has also done a similar > from-the-scratch implementation and it motivated me to pursue further. > > Any feedback on the code is welcome. Although, I want to inform that I > plan to change the locking until after I decide on a good on-disk > layout for the next version, which will by-design minimize the locking > needs, by splitting out freestore from superblock, keep track of > children inode in a better way etc. Also I have been resisting the > urge to look at ext or any other filesystem's design so as to not skew > my thoughts and go with a fresh state of mind and get my own design :) > > Thanks. > > -- > Sankar P > http://psankar.blogspot.com > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
