From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35568 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729111AbeIMTPz (ORCPT ); Thu, 13 Sep 2018 15:15:55 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anand Jain , David Sterba , Sasha Levin Subject: [PATCH 4.18 147/197] btrfs: use device_list_mutex when removing stale devices Date: Thu, 13 Sep 2018 15:31:36 +0200 Message-Id: <20180913131847.435319298@linuxfoundation.org> In-Reply-To: <20180913131841.568116777@linuxfoundation.org> References: <20180913131841.568116777@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Anand Jain [ Upstream commit 7bcb8164ad9435068d9bc3b83b8a002c64d63ff6 ] btrfs_free_stale_devices() finds a stale (not opened) device matching path in the fs_uuid list. We are already under uuid_mutex so when we check for each fs_devices, hold the device_list_mutex too. Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/volumes.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -640,8 +640,11 @@ static void btrfs_free_stale_devices(con struct btrfs_device *device, *tmp_device; list_for_each_entry_safe(fs_devices, tmp_fs_devices, &fs_uuids, fs_list) { - if (fs_devices->opened) + mutex_lock(&fs_devices->device_list_mutex); + if (fs_devices->opened) { + mutex_unlock(&fs_devices->device_list_mutex); continue; + } list_for_each_entry_safe(device, tmp_device, &fs_devices->devices, dev_list) { @@ -661,16 +664,18 @@ static void btrfs_free_stale_devices(con continue; /* delete the stale device */ - if (fs_devices->num_devices == 1) { - btrfs_sysfs_remove_fsid(fs_devices); - list_del(&fs_devices->fs_list); - free_fs_devices(fs_devices); + fs_devices->num_devices--; + list_del(&device->dev_list); + btrfs_free_device(device); + + if (fs_devices->num_devices == 0) break; - } else { - fs_devices->num_devices--; - list_del(&device->dev_list); - btrfs_free_device(device); - } + } + mutex_unlock(&fs_devices->device_list_mutex); + if (fs_devices->num_devices == 0) { + btrfs_sysfs_remove_fsid(fs_devices); + list_del(&fs_devices->fs_list); + free_fs_devices(fs_devices); } } }