From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C86823A1E80 for ; Tue, 24 Feb 2026 15:25:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.9.28.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771946719; cv=none; b=oK4K+PTJMpt8FLtxCST7UlOIVGzbJtkz5ee/0RAxSOnC9OhhWm4Z37lC1r0vXrKR6Njwk89L/mqq+LoFDdBHaWCy8mpzc+epvedUgq8+zGEHvxVDTkW1Hw6Ii4RbA8+msQ1oRY5lFzO+sbWdDK/DYBoDgUA1DqT+Y3mqWdwQI9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771946719; c=relaxed/simple; bh=y1Td8ktXwoJSPrRKZ0fP2h6lcagQl30y0VXis8wxycM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ve+jW/LBB1gd9MBnMc/RTe+nVSDCgp3mB5chOuTp7M5R6ANw+jUENgaJ7X3xEN/5CwmEcONrcSVftlzX8T/0UKZ9ObLDhlDlzXELa1/dYDa2fV+kAEkacWlqBAhoCA3joZr1oOMVtbNLGo2NrPgSfoBXcvcKwx8IlD4GoA91sGc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu; spf=pass smtp.mailfrom=mit.edu; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b=U997oiXo; arc=none smtp.client-ip=18.9.28.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mit.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b="U997oiXo" Received: from macsyma.thunk.org (pool-173-48-111-182.bstnma.fios.verizon.net [173.48.111.182]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 61OFOqSx010759 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 Feb 2026 10:24:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1771946694; bh=xDSAnXoB9ejN/bLi5BfMqVBcp3Wg5UbG7Pg4difgCEo=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=U997oiXoilh/FS+HP/sc9+AhvTSPm0sBVkyHybp7gSa3iwBR/F0vHIr9gMl1tvktL geUmnMAjAkBOiWEs0omBnR23bwxfTcKdEFoorNTnzCi2IANakgSzfbDF1IZtx1UAXD F463L33LgFV/nTPaE90lpwOv4t5pO1N3CMCqURjK5IyTc0SZGaQocu9PBIirS2jT2B 38WkzQSpSshgvUurqCVerpzXVYQ7WTTmiaoofZbkU+I979He89eQrXvo8HWtaqBM7X 9A7bqjC2LHLFwYamCJdTBTMqvXLae972b2/zlSPQXb+TTvh45vFdLkHokDvoOLYd8n XbqE2fwiJvdUw== Received: by macsyma.thunk.org (Postfix, from userid 15806) id EDB4759B421E; Tue, 24 Feb 2026 10:24:51 -0500 (EST) Date: Tue, 24 Feb 2026 10:24:51 -0500 From: "Theodore Tso" To: Eric Biggers Cc: fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Arnd Bergmann , linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH] fsverity: add dependency on 64K or smaller pages Message-ID: <20260224152451.GB16846@macsyma-wired.lan> References: <20260221204525.30426-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260221204525.30426-1-ebiggers@kernel.org> On Sat, Feb 21, 2026 at 12:45:25PM -0800, Eric Biggers wrote: > Currently, all filesystems that support fsverity (ext4, f2fs, and btrfs) > cache the Merkle tree in the pagecache at a 64K aligned offset after the > end of the file data. This offset needs to be a multiple of the page > size, which is guaranteed only when the page size is 64K or smaller. > > 64K was chosen to be the "largest reasonable page size". But it isn't > the largest *possible* page size: the hexagon and powerpc ports of Linux > support 256K pages, though that configuration is rarely used. > > For now, just disable support for FS_VERITY in these odd configurations > to ensure it isn't used in cases where it would have incorrect behavior. > > Fixes: 671e67b47e9f ("fs-verity: add Kconfig and the helper functions for hashing") > Reported-by: Christoph Hellwig > Closes: https://lore.kernel.org/r/20260119063349.GA643@lst.de > Signed-off-by: Eric Biggers Reviewed-by: Theodore Ts'o