File system in a file

File system in a file

[anarchean]

Hi, I'm a undergraduate student and totally new to this kernel devel
thing.

I was asked as an assignment to write a very basic file system, writing
it to a file in my Operating Systems class. I'm really excited with
this subject so I decided that as an self-pleasing extra, I would write
a kernel module to actually make this file system work in a real
operating system (and GNU/Linux is the only true one ;).

I thought about FUSE, but I them I realized it would be very cool
writing a kernel module instead. So, I did some research, I know
FS are access through the VFS interface, I know which functions
and structures to implement. I also read some of the source code
of both ext2 and ecryptfs. And some extra material on the web.

TL;DR; A {
	My question is, if I am writing an file system over a file
	inside another file system, how should I access the file,
	directly via vfs_write/read and flip_open or via a user space
	daemon communicating with the kernel?
}

I know direct writing, using the VFS interface is frowned upon, but
from what I understood, that's what ecryptfs does. And most people
doing it is trying to do so for reading/writing configuration files.

TL;DR; B {
	(Out of curiosity) Is there any big performance implications
	of using vfs_read/write vs communicating with a user space
	daemon?
}

I'm glad for any help you could provide. Thanks!


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