Re: [PATCH v3 06/10] mm/shmem_luo: Don't make early retrieve failures permanent

[Pratyush Yadav <pratyush@kernel.org>]

On Tue, Nov 03 2026, David Matlack wrote:

> Mark failures in shmem_luo_retrieve() before it starts restoring the
> folios as retryable, and return the error without freeing the serialized
> state. If no retrieve succeeds, finish() frees the preserved folios,
> like it does for a file that was never retrieved.
>
> Nothing has consumed the preserved state before the folios are
> restored, so the retrieve can be tried again.
>
> This also fixes leaking the preserved folios when one of these early
> steps fails, e.g. because the file has seals that this kernel doesn't
> support. The retrieve freed the serialized state but not the folios, and
> finish() then skipped the file because its retrieve had failed. There is
> no Fixes tag, since the fix relies on args->retryable, which was only
> added earlier in this series.

If the seals don't match, the retrieve is not retryable. It will always
fail.

I think the only retriable part is memfd_alloc_file(), although even
that is quite unlikely to fail. But I think that also fits pretty well
with the most important type of error you want to retry on, which is bad
arguments. In later patches, you check the argument on
shmem_luo_create_tmpfs_file() or shmem_luo_create_memfd(), so perhaps
set retriable in those functions?

[...]

-- 
Regards,
Pratyush Yadav