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Date:   Sat, 15 Jun 2019 11:31:12 -0400
From:   "Theodore Ts'o" <>
To:     Eric Biggers <>
Cc:,,,,,, Jaegeuk Kim <>,
        Victor Hsieh <>,
        Dave Chinner <>,
        Christoph Hellwig <>,
        "Darrick J . Wong" <>,
        Linus Torvalds <>
Subject: Re: [PATCH v4 14/16] ext4: add basic fs-verity support

On Thu, Jun 06, 2019 at 08:52:03AM -0700, Eric Biggers wrote:
> +/*
> + * Format of ext4 verity xattr.  This points to the location of the verity
> + * descriptor within the file data rather than containing it directly because
> + * the verity descriptor *must* be encrypted when ext4 encryption is used.  But,
> + * ext4 encryption does not encrypt xattrs.
> + */
> +struct fsverity_descriptor_location {
> +	__le32 version;
> +	__le32 size;
> +	__le64 pos;
> +};

What's the benefit of storing the location in an xattr as opposed to
just keying it off the end of i_size, rounded up to next page size (or
64k) as I had suggested earlier?

Using an xattr burns xattr space, which is a limited resource, and it
adds some additional code complexity.  Does the benefits outweigh the
added complexity?

						- Ted

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