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 9F757C4321E for ; Fri, 2 Dec 2022 18:58:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234000AbiLBS61 (ORCPT ); Fri, 2 Dec 2022 13:58:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234273AbiLBS6W (ORCPT ); Fri, 2 Dec 2022 13:58:22 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F07C69C637; Fri, 2 Dec 2022 10:58:21 -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 8CB0B61CD9; Fri, 2 Dec 2022 18:58:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4DC5C433D7; Fri, 2 Dec 2022 18:58:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670007501; bh=HOh3Cp0n7LazD+GQRWKmIbl4e99o0522H/+1Wb/zFpM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jueI8u5WzpHJXBCeK/s4VvCOnYb+rztUFEYYWKB4165BfMWRW5GyhTygwbxjm2WX0 Tx8XueKkLaPFVj+VRFYDOK3LRCtzyrpkwJzIkOr/sv/sOQtsjS3Ar1m+++x5tnsxCW kCUvTXgv909+I5LfeYCwXjff5eR6WT8Ipxpjy2kg1EnYL8tZSoOwqnP4Q5p//pzfuB O1aQIP2YphtTLJMj4IU/3JpUAfxOOISMMi9L2O6aWaJghElC+tyWIOxlKB1SY83zid MWFT3KMYEK0NF74IvZMbByMQ4JX+6x3gDGn7JQeV9V2rUZh9f8qCiuoIgJBXRcWBbK X2gsRBM/jCbrw== Date: Fri, 2 Dec 2022 11:58:17 -0700 From: Keith Busch To: Clay Mayers Cc: Hannes Reinecke , Matthew Wilcox , Chaitanya Kulkarni , "linux-block@vger.kernel.org" , "linux-raid@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "linux-fsdevel@vger.kernel.org" , "axboe@kernel.dk" , "djwong@kernel.org" , "hch@lst.de" , "sagi@grimberg.me" , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" , "javier@javigon.com" , "johannes.thumshirn@wdc.com" , "bvanassche@acm.org" , "dongli.zhang@oracle.com" , "jefflexu@linux.alibaba.com" , "josef@toxicpanda.com" , "clm@fb.com" , "dsterba@suse.com" , "jack@suse.com" , "tytso@mit.edu" , "adilger.kernel@dilger.ca" , "jlayton@kernel.org" , "idryomov@gmail.com" , "danil.kipnis@cloud.ionos.com" , "ebiggers@google.com" , "jinpu.wang@cloud.ionos.com" Subject: Re: [PATCH 0/6] block: add support for REQ_OP_VERIFY Message-ID: References: <20220630091406.19624-1-kch@nvidia.com> <72a51a83-c25a-ef52-55fb-2b73aec70305@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On Fri, Dec 02, 2022 at 05:33:33PM +0000, Clay Mayers wrote: > > > > As long as the protocols don't provide proof-of-work, trying this > > doesn't really prove anything with respect to this concern. > > I'm out of my depth here, but isn't VERIFY tightly related to PI and > at the heart of detecting SAN bit-rot? The proof of work can be via > end-to-end data protection. VERIFY has to actually read to detect bad > host generated PI guard/tags. I'm assuming the PI checks can be > disabled for WRITE and enabled for VERIFY as the test. I suppose if you happen to have a PI formatted drive, you could WRITE garbage Guard tags with PRCHK disabled, then see if VERIFY with PRCHK enabled returns the Guard Check Error; but PI is an optional format feature orthogonal to the VERIFY command: we can't count on that format being available in most implementations.