linux-ext4 - Re: [PATCH v2 00/11] fsverity: support for non-4K pages

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Date:   Tue, 3 Jan 2023 23:25:18 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     Ojaswin Mujoo <ojaswin@...ux.ibm.com>
Cc:     linux-fscrypt@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-btrfs@...r.kernel.org, linux-xfs@...r.kernel.org,
        Andrey Albershteyn <aalbersh@...hat.com>
Subject: Re: [PATCH v2 00/11] fsverity: support for non-4K pages

On Wed, Jan 04, 2023 at 12:08:09PM +0530, Ojaswin Mujoo wrote:
> Hi Eric,
> 
> I have roughly gone through the series and run the (patched) xfstests on
> this patchset on a powerpc machine with 64k pagesize and 64k,4k and 1k
> merkle tree size on EXT4 and everything seems to work correctly. 
> 
> Just for records, test generic/692 takes a lot of time to complete with
> 64k merkel tree size due to the calculations assuming it to be 4k,
> however I was able to manually test that particular scenario. (I'll try
> to send a patch to fix the fstest later).
> 
> Anyways, feel free to add:
> 
> Tested-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
> 
> Since I was not very familiar with the fsverty codebase, I'll try to
> take some more time to review the code and get back with any
> comments/RVBs.
> 
> Regards,
> ojaswin

Thanks Ojaswin!  That's a good point about generic/692.  The right fix for it is
to make it use $FSV_BLOCK_SIZE instead of 4K in its calculations.

I suppose you saw that issue by running the test on ext4 with fs_block_size ==
page_size == 64K, causing xfstests to use merkle_tree_block_size == 64K by
default.  Thanks for doing that; that's something I haven't been able to test
yet.  My focus has been on merkle_tree_block_size < page_size.
merkle_tree_block_size > 4K should just work, though, assuming
merkle_tree_block_size <= min(fs_block_size, page_size).  (Or
merkle_tree_block_size == fs_block_size == page_size before this patch series.)

- Eric