From patchwork Sat May 18 00:47:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jaegeuk Kim X-Patchwork-Id: 10948829 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 C974814C0 for ; Sat, 18 May 2019 00:47:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B6E4C28517 for ; Sat, 18 May 2019 00:47:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAD062851E; Sat, 18 May 2019 00:47:55 +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 3818B28517 for ; Sat, 18 May 2019 00:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726894AbfERAry (ORCPT ); Fri, 17 May 2019 20:47:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:33992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726881AbfERAry (ORCPT ); Fri, 17 May 2019 20:47:54 -0400 Received: from localhost (unknown [104.132.1.68]) (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 47DA721883; Sat, 18 May 2019 00:47:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558140473; bh=wcJMmid3eNX1fzqE7KShQj339cvq5JIkzCDTKY+6qnQ=; h=From:To:Cc:Subject:Date:From; b=lLvPLBZDUqi9n30KQHvC+B/mdzOF1Y5E0ax4t8Cu08ZULeWcxxATpwO7pB8BB55/9 FsB2b1Hjo1kC5w47jpPiqFtz+zJ3zJC2xE0sVxZbLKmCIsRW5t2wkwkQcFeSCycBje AhjCZOZ0fjeCPVI+PSkJ8d2nQuzArr8fiL1/HAUw= From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim , stable@vger.kernel.org, Jens Axboe , linux-block@vger.kernel.org, Bart Van Assche Subject: [PATCH] loop: avoid EAGAIN, if offset or block_size are changed Date: Fri, 17 May 2019 17:47:51 -0700 Message-Id: <20190518004751.18962-1-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 This patch tries to avoid EAGAIN due to nrpages!=0 that was originally trying to drop stale pages resulting in wrong data access. Report: https://bugs.chromium.org/p/chromium/issues/detail?id=938958#c38 Cc: Cc: Jens Axboe Cc: linux-block@vger.kernel.org Cc: Bart Van Assche Fixes: 5db470e229e2 ("loop: drop caches if offset or block_size are changed") Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Signed-off-by: Jaegeuk Kim Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Signed-off-by: Jaegeuk Kim Tested-by: Francesco Ruggeri Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Reported-by: Jaegeuk Kim Signed-off-by: Bart Van Assche Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Reported-by: Jaegeuk Kim Signed-off-by: Bart Van Assche Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Signed-off-by: Jaegeuk Kim Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Signed-off-by: Jaegeuk Kim Reported-by: Gwendal Grignou Reported-by: grygorii tertychnyi Signed-off-by: Jaegeuk Kim Reviewed-by: Bart Van Assche --- drivers/block/loop.c | 44 +++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 27 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 102d79575895..7c7d2d9c47d0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1212,6 +1212,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) kuid_t uid = current_uid(); struct block_device *bdev; bool partscan = false; + bool drop_caches = false; err = mutex_lock_killable(&loop_ctl_mutex); if (err) @@ -1232,10 +1233,8 @@ 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) { - sync_blockdev(lo->lo_device); - kill_bdev(lo->lo_device); - } + lo->lo_sizelimit != info->lo_sizelimit) + drop_caches = true; /* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(lo->lo_queue); @@ -1265,14 +1264,6 @@ 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; @@ -1317,6 +1308,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) bdev = lo->lo_device; partscan = true; } + + /* truncate stale pages cached by previous operations */ + if (!err && drop_caches) { + sync_blockdev(lo->lo_device); + kill_bdev(lo->lo_device); + } out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) @@ -1498,6 +1495,7 @@ 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) { + bool drop_caches = false; int err = 0; if (lo->lo_state != Lo_bound) @@ -1506,23 +1504,10 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg) 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); - } + if (lo->lo_queue->limits.logical_block_size != arg) + drop_caches = true; 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); @@ -1530,6 +1515,11 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg) out_unfreeze: blk_mq_unfreeze_queue(lo->lo_queue); + /* truncate stale pages cached by previous operations */ + if (drop_caches) { + sync_blockdev(lo->lo_device); + kill_bdev(lo->lo_device); + } return err; }