Re: [PATCH v1 1/1] swap: Add exfat to filesystems requiring tst_fill_file

On Wed, Jun 17, 2026 at 03:19:07PM +0000, Andrea Cervesato wrote:
> > I'm just wondering how to implement it better.
> >
> > First of all, we should mention the commit that introduced fallocate()
> > support into exfat inside the patch commit message.
> >
> > Secondly, since the code was already working before v7.1, maybe we should
> > fill the file in exfat only for kernel >= 7.1. But I don't want to touch
> > the core library.
>
> Second update: .swap_activate is not implemented in the linux kernel
> for exfat and the commit causes EINVAL only for swap allocation. That
> is caused by bmap() due to the generic swap activation.
>
> So instead of working around the issue, we probably should have a feature
> in the kernel along with fallocate() support in exfat.
>
> Probably a kernel bug/missing feature.
>
> --
> Andrea Cervesato
> SUSE QE Automation Engineer Linux
> andrea.cervesato-IBi9RG/[email protected]
Hi Andrea,

just to add some context: the regression itself was on the kernel side.
The relevant upstream patch is
https://lore.kernel.org/all/20260603131950.321858-1-japo-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org/.
My understanding is that the kernel-side change did not resolve the issue
for the LTP test suite, and that there was also a separate LTP-relevant
aspect for exfat swapfiles, where actual data writes are required before
swapon() succeeds.

Best regards,
Jan

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