Re: [edk2-devel] GSOC 2021 EXT4 driver Project

["Michael Brown" <mcb30@ipxe.org>]

On 24/05/2021 20:26, Pedro Falcato wrote:
> Me and my project have been selected for GSoC this year, under Michael 
> Kinney and bret. Thank you for the opportunity to collaborate with you 
> and improve Tianocore!
> If anyone has any questions, please fire away :)
> How do I get started? I'd like to find some easier tasks as to start 
> trying out patch submission and generally programming in a firmware 
> environment.
> Also, I've been talking with my mentors and a relevant question to ask 
> the mailing list is: Where should we put the EXT4 driver?
> Michael said there are other filesystems in MdeModulePkg, but it might 
> be getting too big and proposed the following options:
> 
> 1) EXT4 in new package in edk2 repo as a peer to FatPkg.
> 2) EXT4 in edk2 repo in MdeModulePkg
> 3) EXT4 in edk2-platforms advanced feature package.
> 4) EXT4 in edk2 advanced feature package

FWIW, the most natural positioning seems to me to be as a separate 
Ext4Pkg similar to FatPkg.

For the sake of your own sanity, you probably want to start by 
maintaining Ext4Pkg as a completely standalone git repo that you happen 
to place within your local edk2 checkout directory.  This will let you 
develop in isolation without worrying about where the code will 
eventually live, at least until the code has reached a state of maturity 
that makes it worth considering its eventual home.  Keeping it in a 
separate Ext4Pkg repo will also enforce some level of discipline on your 
coding: you'll naturally avoid being tempted into letting your 
development work leak outside of Ext4Pkg into other packages.

In terms of questions, there are two that immediately spring to mind:

- Are you planning on making this read-only, or read-write?

- If you're planning on making it read-write: what simplifications will 
you be able to make to the write path in the UEFI environment?  (UEFI is 
basically a single-user environment in which all filesystem writes 
should be flushed immediately: you may want to consider a simplified 
write path that never uses journalling, for example).

HTH,

Michael