From patchwork Thu Jun 27 05:37:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Marzinski X-Patchwork-Id: 13713844 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 08A71208D7 for ; Thu, 27 Jun 2024 05:38:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719466690; cv=none; b=iD5QWgmNQZVwar8hFLMKe/UKdsL4Ma6hfcE4Mgk5ZDONrTh+pTx4j+qEzxp6w1VeeaE6PkZpJ+jfoMobAgh+MlhRXbUPVr0phVU+hHPNpzI87Rf59c+U7SVvFSTsDLXXPlabtc5nnvAbmrUNGbcHPKFQMddFjT8XowyVrQYYMz0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719466690; c=relaxed/simple; bh=GRwwIUv7iJ4RGfsC5B7yAmmFNjTilNGDhcyS8UU57ws=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tCUxTdwspLt+H39lR58nE17rjeAswnh9sU2YoFTSA3egfNtQ+KdoXJWchzssUZBzbQizbHOOTXyuCU2fOdbRi8Fnhxp3hjp2uMEh+HfeoTY/er3H2TRuf7fWqUjkjpATRhUbpQijM0kdQwDmcbe7My8dZoABKg5wkZuDHuPaUJY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=VJNgHR8o; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VJNgHR8o" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1719466687; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=IQXPRaEuCKaEc6wEFYfrhP1Ewc0GJ9CX9f19YAbzYvE=; b=VJNgHR8oZj5ByTCK3mfE9v+emyqZmrT71R0lWSsBIk6TNKzNgOdyuahfjbepKUVulRLuwk vUcTHKWhFmvYVqfHjCg3T2dgM3/naZEr6CUg86Ygc7rj96Li1Bo9VpHIx1CWhf50RPfXx+ ygbu41kiYZq+HRsx2rIvKUxYmEjhC3U= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-628-nsi0vKbaMCiIRI5dBJWsLg-1; Thu, 27 Jun 2024 01:38:04 -0400 X-MC-Unique: nsi0vKbaMCiIRI5dBJWsLg-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 37C7619560B8; Thu, 27 Jun 2024 05:38:02 +0000 (UTC) Received: from bmarzins-01.fast.eng.rdu2.dc.redhat.com (bmarzins-01.fast.eng.rdu2.dc.redhat.com [10.6.23.12]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6EF2619560B2; Thu, 27 Jun 2024 05:38:01 +0000 (UTC) Received: from bmarzins-01.fast.eng.rdu2.dc.redhat.com (localhost [127.0.0.1]) by bmarzins-01.fast.eng.rdu2.dc.redhat.com (8.17.2/8.17.1) with ESMTPS id 45R5c05O1438653 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 27 Jun 2024 01:38:00 -0400 Received: (from bmarzins@localhost) by bmarzins-01.fast.eng.rdu2.dc.redhat.com (8.17.2/8.17.2/Submit) id 45R5bwcQ1438652; Thu, 27 Jun 2024 01:37:58 -0400 From: Benjamin Marzinski To: Song Liu , Yu Kuai Cc: Heinz Mauelshagen , Xiao Ni , linux-raid@vger.kernel.org Subject: [PATCH] md/raid5: recheck if reshape has finished with device_lock held Date: Thu, 27 Jun 2024 01:37:58 -0400 Message-ID: <20240627053758.1438644-1-bmarzins@redhat.com> Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 When handling an IO request, MD checks if a reshape is currently happening, and if so, where the IO sector is in relation to the reshape progress. MD uses conf->reshape_progress for both of these tasks. When the reshape finishes, conf->reshape_progress is set to MaxSector. If this occurs after MD checks if the reshape is currently happening but before it calls ahead_of_reshape(), then ahead_of_reshape() will end up comparing the IO sector against MaxSector. During a backwards reshape, this will make MD think the IO sector is in the area not yet reshaped, causing it to use the previous configuration, and map the IO to the sector where that data was before the reshape. This bug can be triggered by running the lvm2 lvconvert-raid-reshape-linear_to_raid6-single-type.sh test in a loop, although it's very hard to reproduce. Fix this by rechecking if the reshape has finished after grabbing the device_lock. Fixes: fef9c61fdfabf ("md/raid5: change reshape-progress measurement to cope with reshaping backwards.") Signed-off-by: Benjamin Marzinski --- drivers/md/raid5.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 547fd15115cd..65d9b1ca815c 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5923,15 +5923,17 @@ static enum stripe_result make_stripe_request(struct mddev *mddev, * to check again. */ spin_lock_irq(&conf->device_lock); - if (ahead_of_reshape(mddev, logical_sector, - conf->reshape_progress)) { - previous = 1; - } else { + if (conf->reshape_progress != MaxSector) { if (ahead_of_reshape(mddev, logical_sector, - conf->reshape_safe)) { - spin_unlock_irq(&conf->device_lock); - ret = STRIPE_SCHEDULE_AND_RETRY; - goto out; + conf->reshape_progress)) { + previous = 1; + } else { + if (ahead_of_reshape(mddev, logical_sector, + conf->reshape_safe)) { + spin_unlock_irq(&conf->device_lock); + ret = STRIPE_SCHEDULE_AND_RETRY; + goto out; + } } } spin_unlock_irq(&conf->device_lock);