From patchwork Thu Jan 7 18:17:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauricio Faria de Oliveira X-Patchwork-Id: 12004639 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 F3E12C433E0 for ; Thu, 7 Jan 2021 18:18:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A795C233CF for ; Thu, 7 Jan 2021 18:18:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729292AbhAGSSX (ORCPT ); Thu, 7 Jan 2021 13:18:23 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:49871 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbhAGSSW (ORCPT ); Thu, 7 Jan 2021 13:18:22 -0500 Received: from mail-qk1-f199.google.com ([209.85.222.199]) by youngberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kxZqu-00078J-55 for linux-block@vger.kernel.org; Thu, 07 Jan 2021 18:17:40 +0000 Received: by mail-qk1-f199.google.com with SMTP id x74so6876745qkb.12 for ; Thu, 07 Jan 2021 10:17:40 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=I3X+scLEAwHcaQ88K7i7jawAfpaYGB5qjnrY9nAEImY=; b=TmHyRFY7Hmz5sAoNW6xina0AjxZNnKzkbJi5JyEJy6Xc0mi+4BcoE+FDESa02kaQhZ eVDUZcxVAr9XDwytkT59NFFE9Z3K2bvtTFcbs2KynKIyYW/vcR/YKvw9DoQ3oaRTpSww MlHM5R23gUQbhiJ/qIOA++8/ifcKkCtm4RSiqf0JFuB378qd5Qd4/BIXsIm1NNPPmNfa o3yMKYmOky+tlqAsZOMe9ps3aSlV520kpCbGpGJ9s9u15r5eZB/dYLmj2aSD7qkkCdTk WpDl2lEnbf5bUsrFF2Bq56pYg4A+W1zfecKt4zjNvZ5eCOuPtVeik+nbE1HFqbxc8Q7R kfnA== X-Gm-Message-State: AOAM5330tdcCVuUxQR6S1o4RhrrdboERdSd/ukEmB8oUgIXv7pHVNXhi MsNWvMnFon1rrPu1f3+IU7DAhdqsB3EAq5bNqJ5w+ZheWbT0n6GLbZDY63DzfwKH05mOmHpmwCu DeGKXumrdFE9AiO44uPecN01nxVygOiSyNoxwnZx8 X-Received: by 2002:a05:622a:30e:: with SMTP id q14mr9812129qtw.77.1610043459081; Thu, 07 Jan 2021 10:17:39 -0800 (PST) X-Google-Smtp-Source: ABdhPJw7zlnfaZ0ddOx2kBrn4YOzsWrdkIU1OsIRfmP+K3r0udmp2Fhg5iDCceNCs0+/+/0k4WbAqA== X-Received: by 2002:a05:622a:30e:: with SMTP id q14mr9812112qtw.77.1610043458878; Thu, 07 Jan 2021 10:17:38 -0800 (PST) Received: from localhost.localdomain ([201.82.34.122]) by smtp.gmail.com with ESMTPSA id z78sm3633361qkb.0.2021.01.07.10.17.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Jan 2021 10:17:38 -0800 (PST) From: Mauricio Faria de Oliveira To: Jens Axboe Cc: Ming Lei , linux-block@vger.kernel.org, Gabriel Krisman Bertazi , Eric Desrochers Subject: [PATCH v3] loop: fix I/O error on fsync() in detached loop devices Date: Thu, 7 Jan 2021 15:17:34 -0300 Message-Id: <20210107181734.128296-1-mfo@canonical.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org There's an I/O error on fsync() in a detached loop device if it has been previously attached. The issue is write cache is enabled in the attach path in loop_configure() but it isn't disabled in the detach path; thus it remains enabled in the block device regardless of whether it is attached or not. Now fsync() can get an I/O request that will just be failed later in loop_queue_rq() as device's state is not 'Lo_bound'. So, disable write cache in the detach path. Do so based on the queue flag, not the loop device flag for read-only (used to enable) as the queue flag can be changed via sysfs even on read-only loop devices (e.g., losetup -r.) Test-case: # DEV=/dev/loop7 # IMG=/tmp/image # truncate --size 1M $IMG # losetup $DEV $IMG # losetup -d $DEV Before: # strace -e fsync parted -s $DEV print 2>&1 | grep fsync fsync(3) = -1 EIO (Input/output error) Warning: Error fsyncing/closing /dev/loop7: Input/output error [ 982.529929] blk_update_request: I/O error, dev loop7, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 0 After: # strace -e fsync parted -s $DEV print 2>&1 | grep fsync fsync(3) = 0 Co-developed-by: Eric Desrochers Signed-off-by: Eric Desrochers Signed-off-by: Mauricio Faria de Oliveira Tested-by: Gabriel Krisman Bertazi Reviewed-by: Ming Lei --- drivers/block/loop.c | 3 +++ 1 file changed, 3 insertions(+) v3: - Disable write cache based on QUEUE_FLAG_WC, not just !LO_FLAGS_READ_ONLY, as the former can be enabled in sysfs even for LO_FLAGS_READ_ONLY, thus not disabled later. Mention that in commit message. (thanks, Ming) v2: - Fix ordering of Co-developed-by:/Signed-off-by: tags. (thanks, Krisman) - Add Tested-by: tag. (likewise.) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index e5ff328f0917..e94a11dbb5bd 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1212,6 +1212,9 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) goto out_unlock; } + if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags)) + blk_queue_write_cache(lo->lo_queue, false, false); + /* freeze request queue during the transition */ blk_mq_freeze_queue(lo->lo_queue);