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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 473E6C282DA for ; Sun, 3 Feb 2019 14:01:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E26920815 for ; Sun, 3 Feb 2019 14:01:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729628AbfBCOBq (ORCPT ); Sun, 3 Feb 2019 09:01:46 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53216 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728086AbfBCNtt (ORCPT ); Sun, 3 Feb 2019 08:49:49 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqI9b-0003tj-6t; Sun, 03 Feb 2019 13:49:47 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9W-0006v0-Vo; Sun, 03 Feb 2019 14:49:42 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "David Sterba" , "Jeff Mahoney" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 082/305] btrfs: fix error handling in btrfs_dev_replace_start In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Mahoney commit 5c06147128fbbdf7a84232c5f0d808f53153defe upstream. When we fail to start a transaction in btrfs_dev_replace_start, we leave dev_replace->replace_start set to STARTED but clear ->srcdev and ->tgtdev. Later, that can result in an Oops in btrfs_dev_replace_progress when having state set to STARTED or SUSPENDED implies that ->srcdev is valid. Also fix error handling when the state is already STARTED or SUSPENDED while starting. That, too, will clear ->srcdev and ->tgtdev even though it doesn't own them. This should be an impossible case to hit since we should be protected by the BTRFS_FS_EXCL_OP bit being set. Let's add an ASSERT there while we're at it. Fixes: e93c89c1aaaaa (Btrfs: add new sources for device replace code) Signed-off-by: Jeff Mahoney Reviewed-by: David Sterba Signed-off-by: David Sterba [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- fs/btrfs/dev-replace.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -362,6 +362,7 @@ int btrfs_dev_replace_start(struct btrfs break; case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + ASSERT(0); args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED; goto leave; } @@ -406,6 +407,10 @@ int btrfs_dev_replace_start(struct btrfs if (IS_ERR(trans)) { ret = PTR_ERR(trans); btrfs_dev_replace_lock(dev_replace); + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED; + dev_replace->srcdev = NULL; + dev_replace->tgtdev = NULL; goto leave; } @@ -423,8 +428,6 @@ int btrfs_dev_replace_start(struct btrfs return 0; leave: - dev_replace->srcdev = NULL; - dev_replace->tgtdev = NULL; btrfs_dev_replace_unlock(dev_replace); leave_no_lock: if (tgt_device)