From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793209257; b=r08REJkgv/Ha5AlL0sPl7+OLZzb0RT+BFozYuFK1VcWccG5rXut0ND5o7w8J3wEsJorr tt985hi9xYQEEuJ1PLReXRNruNya0MUoNkiM7VunL5oBh/f+JCIkJD65QN8kWNWSmk3lO /t0ja+ZJdnlFFeEftCq7rdYYJKiI8AL9BCUgnN10KyBo7crV/jdfIVDz/Btc5+LQ3tJLD ke+w1Oaybw5jxMydPx/A1y8QTAekkWagro/84IXr343QC8gw0B7Se27R519+LBVdIZrZt ClCTAiOy5MEhU7TBPGqbJztYbUCoQHuWhc8+iMo+f3im2sjoASmJIZiWZVCyAceh+/g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209257; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=5S+/1olC9YQ0x2Kzx2NQXfaYJMkaoCSjr0KTnPBvGPM=; b=ISCgNFyWxciVq6RyszbutAtF3NLcrS2e3z4ekwNDemhhqqonWOIv5m6DMzVAZhp8rZSm 5iP+PlBDl5XXsZ7vVz6JGh+N049adQu/ZMY1CxKKy6XMNB8+dANb127I1IvqVDqeQmn2W pBUHlYO2jj7WUM/ytyFbOxVQU+/L5967cZ/BPXP6MLltzwNiV6loBhMswlxq0QHTL2SCU Ijc8A0FGpkELNp8P1BRSTrPNZ8In69jFToc2jC+g13KnwHuBnfh6m4gUzTNFX75gmuoXW s3eI7dnmcwhNmnid4mG8MB8aVxFfqmzAz7mPVUktChsyw139yK3SaZq2syE+KV5BTdw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Mst2lHqB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80874606A31A for ; Wed, 28 Oct 2026 17:40:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Mst2lHqB Received: by smtp.kernel.org (Postfix) with ESMTPSA id D64881F01825; Wed, 28 Oct 2026 17:40:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793209257; bh=5S+/1olC9YQ0x2Kzx2NQXfaYJMkaoCSjr0KTnPBvGPM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Mst2lHqB+EBovbnA3pkeMFLpSPgN0ZgS9OEHF4WREB43PfieiQpPlJZ0N3S5NCquD ud+1ov1ylGoKfeEGS7VE6NVsogX+7e7QlOAjCsO/T9lhz5u12M+sckJ2XjLI90SwTk cSwb9YUPjweHlYhjZFCZRuKGf5/pES33y2baXlRPNAgI88f0g6ITZHo9rHrABF6tHA OnKCYAZ6d/xvk0mtVQbbCr8SiH6B84SQm3/jkUNub+dhCwRmVfeSEcicILc+N8hl43 H+R4Ek5u8/Mq4o6JrUsXbate2YyqrJPI4IJYzpHGvWs28IJvxKFYGVSgsSaor/MuKh D+/O+gPETy/XQ== Date: Wed, 28 Oct 2026 11:40:55 -0600 From: Keith Busch To: Jens Axboe Cc: linux-block@vger.kernel.org, Josef Bacik , Christoph Hellwig , Sagi Grimberg Subject: Re: [PATCH 47/98] nvme: refuse metadata sizes above 255 bytes Message-ID: References: <20261028164415.1262013-1-axboe@kernel.dk> <20261028164415.1262013-48-axboe@kernel.dk> X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261028164415.1262013-48-axboe@kernel.dk> On Wed, Oct 28, 2026 at 10:41:50AM -0600, Jens Axboe wrote: > + /* struct blk_integrity has eight bits for the metadata size. */ > + if (head->ms > U8_MAX) > + return false; I've never seen a device with 256 or greater metadata, but if the specs allow it, should the block layer accomodate? It's just the queue_limits, so widening the type isn't a big deal; it fits in the existing padding anyway so the struct doesn't even have to grow. There's potential issues with logical_block_metadata_cap, but that's just user space reporting and doesn't affect the kernel behavior. Seems better than throttling the capacity to 0 for an unsupported format that we can totally support.