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=ham 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 1F09CC2F3BE for ; Mon, 21 Jan 2019 13:50:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E33072063F for ; Mon, 21 Jan 2019 13:50:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078649; bh=DnN6pPw8GWy+0sl/cX74ssCqKGNKyvbkxfzSwdV+sdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CPhm/qmG4GmGkq1BP1jyWhbvToGPP0eBaRqIgqOuHWdD4miRx+0Tlop30n/HKEZcF qJq6VQl+zDs+4hzTiLGCezu+XdeBeGAVWmpDH8KWdEXXIq2J14/Uy7KWRaJV0Pftp2 UdReTmwkd/0tFgl3nXRoqFNmVom6Zze3EfxA00aQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730627AbfAUNur (ORCPT ); Mon, 21 Jan 2019 08:50:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:33424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730598AbfAUNun (ORCPT ); Mon, 21 Jan 2019 08:50:43 -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 BFCED2063F; Mon, 21 Jan 2019 13:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078642; bh=DnN6pPw8GWy+0sl/cX74ssCqKGNKyvbkxfzSwdV+sdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CZTDEfM811UgD3nWFx6KvTyPafgJvzYftZi6utSVRcv9GLNO8ZngMJSnypFcoVCIv +G7pZALQNgNv9mZnF59rnh14lqE5etGH9Airh+Nl8cxOlboAc4vGNBZc7inlkpJLvt xpCJC9Lu1u7yyN6EZoYSO/FFhb74EJl08si8P0H8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Jens Axboe Subject: [PATCH 4.20 104/111] loop: Move special partition reread handling in loop_clr_fd() Date: Mon, 21 Jan 2019 14:43:38 +0100 Message-Id: <20190121122506.834318752@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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit d57f3374ba4817f7c8d26fae8a13d20ac8d31b92 upstream. The call of __blkdev_reread_part() from loop_reread_partition() happens only when we need to invalidate partitions from loop_release(). Thus move a detection for this into loop_clr_fd() and simplify loop_reread_partition(). This makes loop_reread_partition() safe to use without loop_ctl_mutex because we use only lo->lo_number and lo->lo_file_name in case of error for reporting purposes (thus possibly reporting outdate information is not a big deal) and we are safe from 'lo' going away under us by elevated lo->lo_refcnt. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/block/loop.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -630,18 +630,7 @@ static void loop_reread_partitions(struc { int rc; - /* - * bd_mutex has been held already in release path, so don't - * acquire it if this function is called in such case. - * - * If the reread partition isn't from release path, lo_refcnt - * must be at least one and it can only become zero when the - * current holder is released. - */ - if (!atomic_read(&lo->lo_refcnt)) - rc = __blkdev_reread_part(bdev); - else - rc = blkdev_reread_part(bdev); + rc = blkdev_reread_part(bdev); if (rc) pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", __func__, lo->lo_number, lo->lo_file_name, rc); @@ -1095,8 +1084,24 @@ static int __loop_clr_fd(struct loop_dev module_put(THIS_MODULE); blk_mq_unfreeze_queue(lo->lo_queue); - if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) - loop_reread_partitions(lo, bdev); + if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) { + /* + * bd_mutex has been held already in release path, so don't + * acquire it if this function is called in such case. + * + * If the reread partition isn't from release path, lo_refcnt + * must be at least one and it can only become zero when the + * current holder is released. + */ + if (!atomic_read(&lo->lo_refcnt)) + err = __blkdev_reread_part(bdev); + else + err = blkdev_reread_part(bdev); + pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", + __func__, lo->lo_number, err); + /* Device is gone, no point in returning error */ + err = 0; + } lo->lo_flags = 0; if (!part_shift) lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;