From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-99.mta1.migadu.com [95.215.58.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4106B455175 for ; Wed, 9 Sep 2026 07:52:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.99 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788940332; cv=none; b=beeub0YU6Ptu78OVgpxhaR6Q7q0pZki68kEE6AULPevSsAhHxkHTnJFXHl4RxkFLkCgT7YNCz5HVQ6RouycgWmk8NPtDvbbLO+VyMYYhK1AvUw3qyFGZkT2xi0/ShTd8hj17FqgiAq47z7KnKzxiVPWg/63PLkU3Me2LWB1FUng= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788940332; c=relaxed/simple; bh=cnCZ+gc4x6PHqtE0jvXQ8NORTlNmfZNWlaDkGU5s9aY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rfBGDeHa71e04MDzhkyn4OrHkjzkjAlPCojEi40lTuqegZcRp63wa9HJeon5Vo3DkT+gls72k0ca4otsv+GPWZDPqNhFiBxJWOi+5EqnsSvyWT/C7wzR8yrUUzw4UtzcSua8q+cu29uc3sEae1xYpkAez+mgafYlkj1mA6upXrA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=FeSYh8bJ; arc=none smtp.client-ip=95.215.58.99 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="FeSYh8bJ" X-Envelope-To: linux-block@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=cnCZ+gc4x6PHqtE0jvXQ8NORTlNmfZNWlaDkGU5s9aY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788940329; v=1; x=1789545129; b=FeSYh8bJJNib3FN6lpZKtzmXKcD07XWkuIpEwmDlrq72DwrPgmTZ0zPWAELfUif9OD9WZ0la U0OB/3GEuP4okApdQpsiOTHOWoVhX3JQdsVo4rUx+440G9WNfKxcAmwvNobsgZSe3PHVL9IuMJr n75lcoQX4BX8pWN6zJx6JFQM= X-Envelope-To: linux-block@vger.kernel.org Received: by mta12.migadu.com with ESMTPS id 22872cdbe23cad68; Wed, 09 Sep 2026 07:52:09 +0000 X-Mizu-Trace-ID: 22872cdbe23cad68 X-Migadu-Flow: FLOW_OUT Message-ID: <0de31e94-07ed-4d2a-9908-46e1b87b2ba7@linux.dev> Date: Wed, 9 Sep 2026 08:52:07 +0100 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] block: cap atomic write size by PI buffer size constraints To: "Martin K. Petersen" Cc: Christoph Hellwig , Jens Axboe , John Garry , linux-block@vger.kernel.org References: <20260907074111.721054-1-hch@lst.de> <20260907074111.721054-3-hch@lst.de> <8c16f727-c840-4a8f-94a7-fbe09bc3735a@linux.dev> <20260907084621.GA7391@lst.de> <90f94bcd-813d-48f9-a62c-3c703c4a71e6@linux.dev> Content-Language: en-US From: John Garry In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/9/26 03:44, Martin K. Petersen wrote: > > John, > >> As for atomics on disks with integrity support, we decided not to >> support SCSI WRITE ATOMIC (32) - this one is relevant to PI type 2. >> >> But, overall, I'm not sure on this - should we always disable atomics >> for any disk PI? Is there a use case for the two together? Martin? > > I think we were originally just trying limit scope. The two features are > orthogonal, I don't see any particular reason why we shouldn't try to > support them concurrently. > > Type 2 is fairly rare at this point. But it should be fairly trivial to > add support given the existing READ(32)/WRITE(32) plumbing... > Can you please help me understand then how DIF/DIX interacts and atomics - specifically, is the userdata and metadata atomically written together? I would assume so.