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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 0C52BC2F3D5 for ; Mon, 21 Jan 2019 14:17:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF44720861 for ; Mon, 21 Jan 2019 14:17:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548080251; bh=rQ52SiUuWveGlIPwuinXdvw5ymcAcYzZDlXEZKm/Swk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1CgZru65Fd9Ej7gRnwqE9r6E3GnLNEe/fGb0FTMr1b+b8TFdRZ4ErFRDeHIzlFaT2 +T8T1BVkr+tV6WD4Ok8AQ7ezrbuenlolQ7w7iV7I4OoYOwfth0OWnPdKRI2dywN+wt hmsYqeOqEtMeBQmljqj3BuMmhaUwnSFPps3nqTpA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729595AbfAUORY (ORCPT ); Mon, 21 Jan 2019 09:17:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:33028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730537AbfAUNu0 (ORCPT ); Mon, 21 Jan 2019 08:50:26 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EBB5720861; Mon, 21 Jan 2019 13:50:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078625; bh=rQ52SiUuWveGlIPwuinXdvw5ymcAcYzZDlXEZKm/Swk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CPFAUY9UIRkeBamO9t6d+zux+FdOEWPRo2UbQt8Evrkx4jjuP70VCOY5glghL1t7T 3NpNm7pTR3poB3e3BIEfmHtc40LWQtqlh98dQHu3eziTnzjQ9cch6B3wvpyRLy1jSC mVd+KZKeuCHRloQUVa/V8CSElD/9ma8wI9GfZDGs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Jens Axboe Subject: [PATCH 4.20 098/111] loop: Split setting of lo_state from loop_clr_fd Date: Mon, 21 Jan 2019 14:43:32 +0100 Message-Id: <20190121122506.583613147@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190121122455.819406896@linuxfoundation.org> References: <20190121122455.819406896@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit a2505b799a496b7b84d9a4a14ec870ff9e42e11b upstream. Move setting of lo_state to Lo_rundown out into the callers. That will allow us to unlock loop_ctl_mutex while the loop device is protected from other changes by its special state. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/block/loop.c | 52 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 21 deletions(-) --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -975,7 +975,7 @@ static int loop_set_fd(struct loop_devic loop_reread_partitions(lo, bdev); /* Grab the block_device to prevent its destruction after we - * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev). + * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev). */ bdgrab(bdev); return 0; @@ -1025,31 +1025,15 @@ loop_init_xfer(struct loop_device *lo, s return err; } -static int loop_clr_fd(struct loop_device *lo) +static int __loop_clr_fd(struct loop_device *lo) { struct file *filp = lo->lo_backing_file; gfp_t gfp = lo->old_gfp_mask; struct block_device *bdev = lo->lo_device; - if (lo->lo_state != Lo_bound) + if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) return -ENXIO; - /* - * If we've explicitly asked to tear down the loop device, - * and it has an elevated reference count, set it for auto-teardown when - * the last reference goes away. This stops $!~#$@ udev from - * preventing teardown because it decided that it needs to run blkid on - * the loopback device whenever they appear. xfstests is notorious for - * failing tests because blkid via udev races with a losetup - * /do something like mkfs/losetup -d causing the losetup -d - * command to fail with EBUSY. - */ - if (atomic_read(&lo->lo_refcnt) > 1) { - lo->lo_flags |= LO_FLAGS_AUTOCLEAR; - mutex_unlock(&loop_ctl_mutex); - return 0; - } - if (filp == NULL) return -EINVAL; @@ -1057,7 +1041,6 @@ static int loop_clr_fd(struct loop_devic blk_mq_freeze_queue(lo->lo_queue); spin_lock_irq(&lo->lo_lock); - lo->lo_state = Lo_rundown; lo->lo_backing_file = NULL; spin_unlock_irq(&lo->lo_lock); @@ -1110,6 +1093,30 @@ static int loop_clr_fd(struct loop_devic return 0; } +static int loop_clr_fd(struct loop_device *lo) +{ + if (lo->lo_state != Lo_bound) + return -ENXIO; + /* + * If we've explicitly asked to tear down the loop device, + * and it has an elevated reference count, set it for auto-teardown when + * the last reference goes away. This stops $!~#$@ udev from + * preventing teardown because it decided that it needs to run blkid on + * the loopback device whenever they appear. xfstests is notorious for + * failing tests because blkid via udev races with a losetup + * /do something like mkfs/losetup -d causing the losetup -d + * command to fail with EBUSY. + */ + if (atomic_read(&lo->lo_refcnt) > 1) { + lo->lo_flags |= LO_FLAGS_AUTOCLEAR; + mutex_unlock(&loop_ctl_mutex); + return 0; + } + lo->lo_state = Lo_rundown; + + return __loop_clr_fd(lo); +} + static int loop_set_status(struct loop_device *lo, const struct loop_info64 *info) { @@ -1691,11 +1698,14 @@ static void lo_release(struct gendisk *d goto out_unlock; if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { + if (lo->lo_state != Lo_bound) + goto out_unlock; + lo->lo_state = Lo_rundown; /* * In autoclear mode, stop the loop thread * and remove configuration after last close. */ - err = loop_clr_fd(lo); + err = __loop_clr_fd(lo); if (!err) return; } else if (lo->lo_state == Lo_bound) {