From patchwork Tue Oct 17 18:48:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13425712 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 DA33843AB3 for ; Tue, 17 Oct 2023 18:48:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Y3eX7LW/" Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD82F9F; Tue, 17 Oct 2023 11:48:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=oX4lK1dfp58L5xH7/9zRG/fX7LPq226bYG22aZQTTco=; b=Y3eX7LW/yg1a5UHuEm5j8dX+1w 54lZBmXwcmu/0mYRF8xdAiRRwmARSOJB4jRUtGOdm9OihJjKmd5LDb1NMi61YNiXV4PYIgYKVhh5Y S1UZ1fSzAcMUXqIXt+SSl2MU6D1D1btmeHRXymrQUcTH7Frp1BW8IWU73iAQjfxHlSrtnJKYXc1t8 PolLzlyWrWt7BcQ12xHEseKTc+5ZbfSJW5exXvtETxsvVAc9mLliBfMNysy27jj6CCfK18onsuVdG aTEpBVzUN2P7PA7QpE/2ACPgvHbANLRny5Zc1+sis4zOYSd4pN13erV7qGrO3d+PLVw0vWse/zYjU D9R6UvHg==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qsp7J-00D0Ku-1I; Tue, 17 Oct 2023 18:48:33 +0000 From: Christoph Hellwig To: Christian Brauner , Al Viro , Jens Axboe Cc: Jan Kara , Denis Efremov , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 2/5] block: WARN_ON_ONCE() when we remove active partitions Date: Tue, 17 Oct 2023 20:48:20 +0200 Message-Id: <20231017184823.1383356-3-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231017184823.1383356-1-hch@lst.de> References: <20231017184823.1383356-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Christian Brauner The logic for disk->open_partitions is: blkdev_get_by_*() -> bdev_is_partition() -> blkdev_get_part() -> blkdev_get_whole() // bdev_whole->bd_openers++ -> if (part->bd_openers == 0) disk->open_partitions++ part->bd_openers In other words, when we first claim/open a partition we increment disk->open_partitions and only when all part->bd_openers are closed will disk->open_partitions be zero. That should mean that disk->open_partitions is always > 0 as long as there's anyone that has an open partition. So the check for disk->open_partitions should meand that we can never remove an active partition that has a holder and holder ops set. Assert that in the code. The main disk isn't removed so that check doesn't work for disk->part0 which is what we want. After all we only care about partition not about the main disk. Signed-off-by: Christian Brauner Reviewed-by: Ming Lei Reviewed-by: Jan Kara --- block/partitions/core.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/block/partitions/core.c b/block/partitions/core.c index b0585536b407a5..f47ffcfdfcec22 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -274,17 +274,6 @@ void drop_partition(struct block_device *part) put_device(&part->bd_device); } -static void delete_partition(struct block_device *part) -{ - /* - * Remove the block device from the inode hash, so that it cannot be - * looked up any more even when openers still hold references. - */ - remove_inode_hash(part->bd_inode); - bdev_mark_dead(part, false); - drop_partition(part); -} - static ssize_t whole_disk_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -674,8 +663,23 @@ int bdev_disk_changed(struct gendisk *disk, bool invalidate) sync_blockdev(disk->part0); invalidate_bdev(disk->part0); - xa_for_each_start(&disk->part_tbl, idx, part, 1) - delete_partition(part); + xa_for_each_start(&disk->part_tbl, idx, part, 1) { + /* + * Remove the block device from the inode hash, so that + * it cannot be looked up any more even when openers + * still hold references. + */ + remove_inode_hash(part->bd_inode); + + /* + * If @disk->open_partitions isn't elevated but there's + * still an active holder of that block device things + * are broken. + */ + WARN_ON_ONCE(atomic_read(&part->bd_openers)); + invalidate_bdev(part); + drop_partition(part); + } clear_bit(GD_NEED_PART_SCAN, &disk->state); /*