[RFC] exfat-nofuse: fix compile error on kernel 4.18+

[dengqf6]

Switched to https://github.com/AndyLavr/exfat-nofuse

Maintainer: @yousong @diizzyy
Compile tested: mvebu kernel 4.19.10; ramip kernel 4.14.88
Run tested: mvebu kernel 4.19.10

[yousong]

please just bump the version and do some basic rw test there as well. for master branch, picking patches for out of tree modules is not necessary.

[diizzyy]

Perhaps it's time for another look at sdfat which is more "active" in that regard?
https://github.com/cryptomilk/kernel-sdfat
I'd also think we should do a runtime test just to be safe.

[dengqf6]

@diizzyy The sdfat driver doesn't support 4.18+, either.
I found a more recent fork which supports 4.18+, https://github.com/AndyLavr/exfat-nofuse, but it doesn't have backward compatibility.

And of course I did some rw test, I already have an exFAT USB flash drive attached to it

[diizzyy]

@dengqf6
My "concern" is that sdfat seems to follow upstream much more closely compared the current repo. Having said that I don't have enough knowledge to evalutate the quality between the two repos so my concern might be unjustified.

[dengqf6]

@AndyLavr @cryptomilk

[cryptomilk]

The sdfat kernel driver is the successor of exfat. You should use sdfat and it shouldn't be that hard to get it working on a newer kernel.

[dengqf6]

Switched to https://github.com/AndyLavr/exfat-nofuse
Added a patch to fix backward compatibility.

[yousong]

Looks like the dorimanx/exfat-nofuse repo hasn't been updated for a few months. It will take me a while to evaluate switching to another fork.

the maintenance work of building out of tree module against different kernel versions is very big. If this package goes in that direction too far, I may propose to drop it from OpenWrt. Right now a few dozen patches should be fine.

As for the cryptomilk/kernel-sdfat repo, if you really need it, open a pull request for review. It can exist as a separate package with dependency on LINUX_4_4.

[diizzyy]

#6238 ?
I'm not sure if we need to modify the defaults and/or set anything regarding the kernel config.

[yousong]

Sorry, it seems to me the AndyLavr/exfat-nofuse fork has its own goal of fitting with its own forked dragon kernel, not geared/maintained for use in OpenWrt or other distro.

I cannot find any targets in OpenWrt trunk switched to 4.19 yet, as such I tend to close this pull request for now.

The plan would be keep picking minor patches from dorimanx/exfat-nofuse so that the package at least compiles and works out of box in the near future. Then at some point when it's clear that the module is really abandoned upstream, I will propose to just drop it here.

[dengqf6]

OK, let's carry a patch like Arch Linux did..

[dengqf6]

As @diizzyy mentioned here dorimanx/exfat-nofuse#102 (comment), https://github.com/coolshou/exfat seems like another option