Enable kernel config required for DFS

[jabbera]

Is your feature request related to a problem? Please describe.
I'm unable to mount a CIFS DFS share because the kernel doesn't have support and DRVFS is too slow to be useful. WSL2 is being sold as the easy way to interop between Linux and windows yet I can't mount one of the most basic enterprise shares. It's so incredibly frustrating I can't even being to explain it.

Describe the solution you'd like
I'd the kernel to be DFS enabled.

Describe alternatives you've considered
DrvFS - too slow
Compiling my own kernel - Ew
Mounting the servers directly without DFS - also Ew

Additional context
Please enable the following kernel configs:

CONFIG_CIFS_UPCALL=y
CONFIG_CIFS_DFS_UPCALL=y
CONFIG_CIFS_SWN_UPCALL=y

[jabbera]

I'm not alone! #5534

[elsaco]

IMO, your best option is Ew, compile your own kernel. Adding all sorts of storage protocols ( LIO was requested in #9511 few days ago) makes the kernel blob larger. Soon we'll need 8GB of RAM to load the kernel only 🤷‍♂️

[jabbera]

I'm doing that now but considering dfs is a first class MSFT product offering I'd assume it would be supported in wsl

[jabbera]

This is blocked by: #9540

[juliusl]

@elsaco For virtualization development 8GB of start-up RAM is pretty reasonable. For example, that's the amount needed to start windows server on Hyper-V.

Would it be feasible to have multiple kernel builds then? 1 for default and another for "extended-io-features" or even "full-upstream-parity"?