From patchwork Wed Nov 13 10:27:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Thumshirn X-Patchwork-Id: 11241659 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F37FC1850 for ; Wed, 13 Nov 2019 10:27:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D470922459 for ; Wed, 13 Nov 2019 10:27:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727394AbfKMK1n (ORCPT ); Wed, 13 Nov 2019 05:27:43 -0500 Received: from mx2.suse.de ([195.135.220.15]:48200 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726613AbfKMK1i (ORCPT ); Wed, 13 Nov 2019 05:27:38 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0AFDCB5FA; Wed, 13 Nov 2019 10:27:37 +0000 (UTC) From: Johannes Thumshirn To: David Sterba Cc: Qu Wenru , Linux BTRFS Mailinglist , Johannes Thumshirn Subject: [PATCH v2 3/7] btrfs: handle allocation failure in strdup Date: Wed, 13 Nov 2019 11:27:24 +0100 Message-Id: <20191113102728.8835-4-jthumshirn@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20191113102728.8835-1-jthumshirn@suse.de> References: <20191113102728.8835-1-jthumshirn@suse.de> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Gracefully handle allocation failures in btrfs_close_one_device()'s rcu_string_strdup() instead of crashing the machine. Signed-off-by: Johannes Thumshirn --- fs/btrfs/volumes.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 0a2a73907563..e5864ca3bb3b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1064,7 +1064,7 @@ static void btrfs_close_bdev(struct btrfs_device *device) static int btrfs_close_one_device(struct btrfs_device *device) { struct btrfs_fs_devices *fs_devices = device->fs_devices; - struct btrfs_device *new_device; + struct btrfs_device *new_device = NULL; struct rcu_string *name; new_device = btrfs_alloc_device(NULL, &device->devid, @@ -1072,6 +1072,15 @@ static int btrfs_close_one_device(struct btrfs_device *device) if (IS_ERR(new_device)) goto err_close_device; + /* Safe because we are under uuid_mutex */ + if (device->name) { + name = rcu_string_strdup(device->name->str, GFP_NOFS); + if (!name) + goto err_free_device; + + rcu_assign_pointer(new_device->name, name); + } + if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) && device->devid != BTRFS_DEV_REPLACE_DEVID) { list_del_init(&device->dev_alloc_list); @@ -1085,13 +1094,6 @@ static int btrfs_close_one_device(struct btrfs_device *device) if (device->bdev) fs_devices->open_devices--; - /* Safe because we are under uuid_mutex */ - if (device->name) { - name = rcu_string_strdup(device->name->str, GFP_NOFS); - BUG_ON(!name); /* -ENOMEM */ - rcu_assign_pointer(new_device->name, name); - } - list_replace_rcu(&device->dev_list, &new_device->dev_list); new_device->fs_devices = device->fs_devices; @@ -1100,6 +1102,10 @@ static int btrfs_close_one_device(struct btrfs_device *device) return 0; +err_free_device: + if (new_device) + btrfs_free_device(new_device); + err_close_device: btrfs_close_bdev(device); if (device->bdev) {