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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 DBB7DC31E5D for ; Mon, 17 Jun 2019 21:09:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF06820861 for ; Mon, 17 Jun 2019 21:09:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560805746; bh=6w8yrWjqkeTzBpJ7KVJUZlACUNkm5omGdqQehZb4gN8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Boxdj/Ymr6vYKW7D3+N8EtUwRVY1DL7YkYg3eVJBu9x8QgRNu0zBaH8qnkCjP15w2 3uEiwkic2Hbx/2fXDKxNFJUqIPgzwM4FZWp4hIQ0kqTJ3569G2Qz2tHuX/DAj7rygr m92DjhrmiOsTFn67P+HW9Z1ylSEZDi372V6kOtx8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727731AbfFQVJF (ORCPT ); Mon, 17 Jun 2019 17:09:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:37978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725497AbfFQVIu (ORCPT ); Mon, 17 Jun 2019 17:08:50 -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 11D5220861; Mon, 17 Jun 2019 21:08:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560805729; bh=6w8yrWjqkeTzBpJ7KVJUZlACUNkm5omGdqQehZb4gN8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZnEWK6U1mwJYufDZy7rIPD9pbHmJfim2W495iQX2+WxMR31nYtsHaNBKjW34ZtRot +DdWvqpp4vDhCUFl65AmV5plp3YKBLVjdflqSaMjFojgKuHqsfl4IXofLsH1m3us5F iZ8z7Qb0fcLm0mdkpSJbZdV078HcjsRTIAjEhxzI= Date: Mon, 17 Jun 2019 14:08:48 -0700 From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jens Axboe , linux-block@vger.kernel.org, Bart Van Assche , stable@vger.kernel.org Subject: Re: [f2fs-dev] [PATCH v2] loop: avoid EAGAIN, if offset or block_size are changed Message-ID: <20190617210848.GB57907@jaegeuk-macbookpro.roam.corp.google.com> References: <20190518004751.18962-1-jaegeuk@kernel.org> <20190518005304.GA19446@jaegeuk-macbookpro.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190518005304.GA19446@jaegeuk-macbookpro.roam.corp.google.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Jens, Any chance to get a review for this? (Added Tested-by:) On 05/17, Jaegeuk Kim wrote: > 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 Tested-by: Francesco Ruggeri > Signed-off-by: Jaegeuk Kim > --- > v2 from v1: > - remove obsolete jump > > drivers/block/loop.c | 45 +++++++++++++++++--------------------------- > 1 file changed, 17 insertions(+), 28 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index 102d79575895..42994de2dd12 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) > @@ -1506,30 +1504,21 @@ 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); > loop_update_dio(lo); > -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; > } > > -- > 2.19.0.605.g01d371f741-goog > > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel