From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 858FDC4332F for ; Tue, 13 Dec 2022 20:39:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236776AbiLMUjo (ORCPT ); Tue, 13 Dec 2022 15:39:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235679AbiLMUjn (ORCPT ); Tue, 13 Dec 2022 15:39:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E03614D19; Tue, 13 Dec 2022 12:39:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C435B61539; Tue, 13 Dec 2022 20:39:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C996C433D2; Tue, 13 Dec 2022 20:39:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670963981; bh=iqmnRcLzovr7AC8+O+z/TL7d5dOtxq+rCVzO+zKWMF0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VvyXz4OfIm+//NGHUZop571fzQR48B+BzJqViL2SeQ5zfqNXbBJ4q5kp2Gj24vU1j zO8zsK5fFS9cADogTL6rEq4uLij/fG9nhaCamjzdEPu2dHi2YeSzR2L6j5Zuf4wcLh QMoMzPbjLmx+su3SR8z3W38vbiqVJFXAnfCIqE2r/w4yOAvV4lqwz4Q3WdNqytkXMN PlaqDgfGAzExipK3hj7PX5F/CQZspGs4DAugpne4KhQZE8kGWpzomwYsTOT8GrAMya b5Jl1J7ruohxunpUqPl2dKh1xXVFbQ5E50eF+q9iM7C0Lweowom927v5IgBbioEJJW A6GgTTZizgBZA== Date: Tue, 13 Dec 2022 12:39:39 -0800 From: Eric Biggers To: Dave Chinner Cc: Andrey Albershteyn , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH 10/11] xfs: add fs-verity support Message-ID: References: <20221213172935.680971-1-aalbersh@redhat.com> <20221213172935.680971-11-aalbersh@redhat.com> <20221213203319.GV3600936@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221213203319.GV3600936@dread.disaster.area> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Dec 14, 2022 at 07:33:19AM +1100, Dave Chinner wrote: > On Tue, Dec 13, 2022 at 11:08:45AM -0800, Eric Biggers wrote: > > On Tue, Dec 13, 2022 at 06:29:34PM +0100, Andrey Albershteyn wrote: > > > > > > Also add check that block size == PAGE_SIZE as fs-verity doesn't > > > support different sizes yet. > > > > That's coming with > > https://lore.kernel.org/linux-fsdevel/20221028224539.171818-1-ebiggers@kernel.org/T/#u, > > which I'll be resending soon and I hope to apply for 6.3. > > Review and testing of that patchset, along with its associated xfstests update > > (https://lore.kernel.org/fstests/20221211070704.341481-1-ebiggers@kernel.org/T/#u), > > would be greatly appreciated. > > > > Note, as proposed there will still be a limit of: > > > > merkle_tree_block_size <= fs_block_size <= page_size > > > Hopefully you don't need fs_block_size > page_size or > > Yes, we will. > > This back on my radar now that folios have settled down. It's > pretty trivial for XFS to do because we already support metadata > block sizes > filesystem block size. Here is an old prototype: > > https://lore.kernel.org/linux-xfs/20181107063127.3902-1-david@fromorbit.com/ As per my follow-up response (https://lore.kernel.org/r/Y5jc7P1ZeWHiTKRF@sol.localdomain), I now think that wouldn't actually be a problem. > > merkle_tree_block_size > fs_block_size? > > That's also a desirable addition. > > XFS is using xattrs to hold merkle tree blocks so the merkle tree > storage is are already independent of the filesystem block size and > page cache limitations. Being able to using 64kB merkle tree blocks > would be really handy for reducing the search depth and overall IO > footprint of really large files. Well, the main problem is that using a Merkle tree block of 64K would mean that you can never read less than 64K at a time. - Eric