Re: [QUESTION] Does fs-verity support large folios / large block size in ext4?

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Nov 06, 2025 at 09:02:53PM +0800, Baokun Li wrote:
> I have recently been working on enabling large block size support in ext4.
> I had assumed that fs-verity does not support large folios / large block
> size. However, when testing with 64k LBS using:
> 
>     `kvm-xfstests -c ext4/64k -g verity -x encrypt`
> 
> the tests passed successfully.
> 
> Is this just a coincidence, or has fs-verity code already been updated to
> support large block size / large folios?

It might work already.  I already added support for verifying data from
large folios several years ago:

    commit 5d0f0e57ed900917836385527ce5b122fa1425a3
    Author: Eric Biggers <ebiggers@google.com>
    Date:   Fri Jan 27 14:15:29 2023 -0800

        fsverity: support verifying data from large folios

Note that the Merkle tree block size is still limited to <= PAGE_SIZE.
But that's fine for now; generally people want 4K Merkle tree blocks
anyway.  So the configuration in question, which should be getting
tested when you run that command and should theoretically work, should
be: filesystem_block_size=64K, PAGE_SIZE=4K, merkle_tree_block_size=4K.

Is there a git tree with your work that I can take a look at and confirm
that this is happening?

- Eric