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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 844C7C433FF for ; Mon, 29 Jul 2019 20:24:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F5D820679 for ; Mon, 29 Jul 2019 20:24:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726129AbfG2UYG (ORCPT ); Mon, 29 Jul 2019 16:24:06 -0400 Received: from len.romanrm.net ([91.121.75.85]:43038 "EHLO len.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727679AbfG2UYG (ORCPT ); Mon, 29 Jul 2019 16:24:06 -0400 X-Greylist: delayed 314 seconds by postgrey-1.27 at vger.kernel.org; Mon, 29 Jul 2019 16:24:05 EDT Received: from natsu (unknown [IPv6:fd39::e99e:8f1b:cfc9:ccb8]) by len.romanrm.net (Postfix) with SMTP id 3D8BE202D3; Mon, 29 Jul 2019 20:18:50 +0000 (UTC) Date: Tue, 30 Jul 2019 01:18:50 +0500 From: Roman Mamedov To: "Guilherme G. Piccoli" Cc: linux-raid@vger.kernel.org, linux-block@vger.kernel.org, dm-devel@redhat.com, jay.vosburgh@canonical.com, NeilBrown , Song Liu Subject: Re: [PATCH] md/raid0: Fail BIOs if their underlying block device is gone Message-ID: <20190730011850.2f19e140@natsu> In-Reply-To: <20190729193359.11040-1-gpiccoli@canonical.com> References: <20190729193359.11040-1-gpiccoli@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, 29 Jul 2019 16:33:59 -0300 "Guilherme G. Piccoli" wrote: > Currently md/raid0 is not provided with any mechanism to validate if > an array member got removed or failed. The driver keeps sending BIOs > regardless of the state of array members. This leads to the following > situation: if a raid0 array member is removed and the array is mounted, > some user writing to this array won't realize that errors are happening > unless they check kernel log or perform one fsync per written file. > > In other words, no -EIO is returned and writes (except direct ones) appear > normal. Meaning the user might think the wrote data is correctly stored in > the array, but instead garbage was written given that raid0 does stripping > (and so, it requires all its members to be working in order to not corrupt > data). If that's correct, then this seems to be a critical weak point in cases when we have a RAID0 as a member device in RAID1/5/6/10 arrays. -- With respect, Roman