<--dentries ^--VFS--^ staticfs-->

How to write a Linux VFS filesystem module - continued

March 8, 2004

Analysis continued

At this point, we've looked fully through the ramfs module. But do I feel like I know everything I need to write my own VFS module? Nope. I think part of the problem is that with ramfs, there are things that the VFS module leaves in memory (because the kernel has them there), and therefore there are some tasks missing. Looking at romfs might highlight some of these discrenpancies, but we'd still be missing a good example of writing to a filesystem -- ramfs does it to memory, and romfs doesn't do it at all!

This is important, because the VFS takes care to worry about multiple processes using a filesystem, or even a given inode. There are probably things that we should take care of as a VFS module writer, but what are they?

romfs seems to be another good example of a simple VFS filesystem, but I don't know how much more I'll learn from it. Do I really want to try and look at a "real" filesystem, one that actually modifies files on a partition, making me then have to work around the filesystem-specific code to figure out the filesystem-generic code? Do I just start writing my own and see what walls I hit?

March 9, 2004

I think so. I think what I'm going to do is try to write a simplistic filesystem just to see if I understand certain parts of this VFS system.
<--dentries ^--VFS--^ staticfs-->

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