From patchwork Mon Feb 22 15:41:23 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: 12098965 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=-16.7 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 2BD82C433DB for ; Mon, 22 Feb 2021 15:42:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBD5D64E74 for ; Mon, 22 Feb 2021 15:42:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230317AbhBVPmf (ORCPT ); Mon, 22 Feb 2021 10:42:35 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39861 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230036AbhBVPm1 (ORCPT ); Mon, 22 Feb 2021 10:42:27 -0500 Received: from mail-qk1-f197.google.com ([209.85.222.197]) by youngberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1lEDLD-00019c-Cy for linux-block@vger.kernel.org; Mon, 22 Feb 2021 15:41:43 +0000 Received: by mail-qk1-f197.google.com with SMTP id r15so9436861qke.5 for ; Mon, 22 Feb 2021 07:41:43 -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=vrhpPKzimuceCgC93oDFemcstTw5fQ1szdLIsIshKp8=; b=cyVJFDfMz2KfpcI7+3Fw3BJ+A/YrCteZFjhYMIyah/eYrqjcTDeQrHuswV1072QbLU TxXeEbK76AfM38ZDG+667t+6kfVjWA8yItaD3XbCQUL5HOmlOETPGqJP9q2km1pnx7gw QZ2PfMS+9z1W2bDle+V/qMlkcgSmGfV5Gkrq1wmf1ObtdwS3kWvvKzpQ7kEYNDX/+NVc xkqdPba2CbA1hh+BhZjhHbEWHupo4cgc9pvvSQm9TYUjS9QwevAmb4OpkcXu1J7EIOJb tkaP3LCUx1+Z1S0og72P2ISsS3s2lW7TnAZx1Yfxl82SAZoEw/nOoGqNqh1cEXNROcwV SJlA== X-Gm-Message-State: AOAM532rIIvrjZU1eKnFCaWMZO+j32URO0QrdJMXhTVBonEJt+Y8PQTd dK2jiYuORF6WMwDV5/esXHcznfnHynftvcTmJ/cVj8ACgCoFRJzbSZwLnSgimq/FreRE1o+ZvOZ 4ic9ScQtWXpVyh9NDb879B7HacYA9BTqC6rXLX5D/ X-Received: by 2002:ac8:5651:: with SMTP id 17mr7326055qtt.16.1614008502513; Mon, 22 Feb 2021 07:41:42 -0800 (PST) X-Google-Smtp-Source: ABdhPJxLhXaaiCO/evjVkr0RG8kQA1G6hbwR1y4mKbBd/mknD20/5MsrTSVXO4jf0eDsCLl4XtmVbg== X-Received: by 2002:ac8:5651:: with SMTP id 17mr7326028qtt.16.1614008502247; Mon, 22 Feb 2021 07:41:42 -0800 (PST) Received: from localhost.localdomain ([2804:14c:4e6:9293:753:8a4c:6a34:9239]) by smtp.gmail.com with ESMTPSA id j2sm12336978qkk.96.2021.02.22.07.41.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Feb 2021 07:41:41 -0800 (PST) From: Mauricio Faria de Oliveira To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, ming.lei@redhat.com, krisman@collabora.com, eric.desrochers@canonical.com Subject: [PATCH RESEND v4] loop: fix I/O error on fsync() in detached loop devices Date: Mon, 22 Feb 2021 12:41:23 -0300 Message-Id: <20210222154123.61797-1-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 --- v4: - Add Reviewed-By: tag (thanks, Ming.) 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.) drivers/block/loop.c | 3 +++ 1 file changed, 3 insertions(+) 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);