From patchwork Thu Jan 10 03:17:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jaegeuk Kim X-Patchwork-Id: 10755157 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 753C013B5 for ; Thu, 10 Jan 2019 03:17:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D0672920D for ; Thu, 10 Jan 2019 03:17:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4E0D529211; Thu, 10 Jan 2019 03:17:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F9B42920D for ; Thu, 10 Jan 2019 03:17:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726950AbfAJDRW (ORCPT ); Wed, 9 Jan 2019 22:17:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:43894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726637AbfAJDRW (ORCPT ); Wed, 9 Jan 2019 22:17:22 -0500 Received: from localhost (unknown [104.132.1.85]) (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 93E7D2075C; Thu, 10 Jan 2019 03:17:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547090241; bh=pIeK3c4tC8cvCELbLlBXG6zOM4HitYtNfIgsBDsgVvQ=; h=From:To:Cc:Subject:Date:From; b=EF8PLJPQxhyfZPIuYaG/f7LmVnekIMFRvsjPwP5jhYa4UE+hPY+HOEdyPJSCGmLN6 4lF/0d1Hgmj+HCrjvnR/12A+GG7wPF8q6ExN9ZNuX2BQqJyKyHnjFeqhE/BJaKQ7Na Rf9xsQJXcRmPqJFH6qpB2lvj8DdqdMQaEXIte3eo= From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: jaegeuk@kernel.org, Jens Axboe , linux-block@vger.kernel.org Subject: [PATCH] loop: drop caches if offset or block_size are changed Date: Wed, 9 Jan 2019 19:17:14 -0800 Message-Id: <20190110031714.39000-1-jaegeuk@kernel.org> X-Mailer: git-send-email 2.19.0.605.g01d371f741-goog MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we don't drop caches used in old offset or block_size, we can get old data from new offset/block_size, which gives unexpected data to user. For example, Martijn found a loopback bug in the below scenario. 1) LOOP_SET_FD loads first two pages on loop file 2) LOOP_SET_STATUS64 changes the offset on the loop file 3) mount is failed due to the cached pages having wrong superblock Cc: Jens Axboe Cc: linux-block@vger.kernel.org Reported-by: Martijn Coenen Reviewed-by: Bart Van Assche Signed-off-by: Jaegeuk Kim --- drivers/block/loop.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index b8a0720d3653..cf5538942834 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1190,6 +1190,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) goto out_unlock; } + if (lo->lo_offset != info->lo_offset || + lo->lo_sizelimit != info->lo_sizelimit) { + sync_blockdev(lo->lo_device); + kill_bdev(lo->lo_device); + } + /* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(lo->lo_queue); @@ -1218,6 +1224,14 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) { + /* kill_bdev should have truncated all the pages */ + if (lo->lo_device->bd_inode->i_mapping->nrpages) { + err = -EAGAIN; + pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", + __func__, lo->lo_number, lo->lo_file_name, + lo->lo_device->bd_inode->i_mapping->nrpages); + goto out_unfreeze; + } if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) { err = -EFBIG; goto out_unfreeze; @@ -1443,22 +1457,39 @@ static int loop_set_dio(struct loop_device *lo, unsigned long arg) static int loop_set_block_size(struct loop_device *lo, unsigned long arg) { + int err = 0; + if (lo->lo_state != Lo_bound) return -ENXIO; if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg)) return -EINVAL; + if (lo->lo_queue->limits.logical_block_size != arg) { + sync_blockdev(lo->lo_device); + kill_bdev(lo->lo_device); + } + blk_mq_freeze_queue(lo->lo_queue); + /* kill_bdev should have truncated all the pages */ + if (lo->lo_queue->limits.logical_block_size != arg && + lo->lo_device->bd_inode->i_mapping->nrpages) { + err = -EAGAIN; + pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", + __func__, lo->lo_number, lo->lo_file_name, + lo->lo_device->bd_inode->i_mapping->nrpages); + goto out_unfreeze; + } + blk_queue_logical_block_size(lo->lo_queue, arg); blk_queue_physical_block_size(lo->lo_queue, arg); blk_queue_io_min(lo->lo_queue, arg); loop_update_dio(lo); - +out_unfreeze: blk_mq_unfreeze_queue(lo->lo_queue); - return 0; + return err; } static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,