From patchwork Sat May 30 15:32:25 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anand Jain X-Patchwork-Id: 6513251 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 443F79F1C1 for ; Sat, 30 May 2015 15:32:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 693B02051F for ; Sat, 30 May 2015 15:32:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EC1020392 for ; Sat, 30 May 2015 15:32:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754733AbbE3Pcs (ORCPT ); Sat, 30 May 2015 11:32:48 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:34667 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753479AbbE3Pcq (ORCPT ); Sat, 30 May 2015 11:32:46 -0400 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t4UFWhfO011182 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 30 May 2015 15:32:43 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.13.8/8.13.8) with ESMTP id t4UFWhPn025411 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Sat, 30 May 2015 15:32:43 GMT Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by userv0122.oracle.com (8.13.8/8.13.8) with ESMTP id t4UFWgFb026479; Sat, 30 May 2015 15:32:43 GMT Received: from localhost.localdomain (/117.219.182.58) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 30 May 2015 08:32:42 -0700 From: Anand Jain To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz Subject: [PATCH v5.2 24/42] Btrfs: free the stale device Date: Sat, 30 May 2015 23:32:25 +0800 Message-Id: <1432999945-4320-1-git-send-email-Anand.Jain@oracle.com> X-Mailer: git-send-email 2.0.0.257.g75cc6c6 In-Reply-To: <1426845702-6298-25-git-send-email-anand.jain@oracle.com> References: <1426845702-6298-25-git-send-email-anand.jain@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When the btrfs on a device is overwritten with a new btrfs (mkfs), the old btrfs instance in the kernel becomes stale. So with this patch if kernel finds device is overwritten then delete the stale fsid/uuid. Signed-off-by: Anand Jain --- v5.1->v5.2: accepts David's review comments with thanks. esp.ly the important rcu part v5->v5.1: since this deals with only devices in unmounted state, don't try to remove device link fs/btrfs/volumes.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e50005f..0a4df7a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -445,6 +445,62 @@ static void pending_bios_fn(struct btrfs_work *work) run_scheduled_bios(device); } + +void btrfs_free_stale_device(struct btrfs_device *cur_dev) +{ + struct btrfs_fs_devices *fs_devs; + struct btrfs_device *dev; + + if (!cur_dev->name) + return; + + list_for_each_entry(fs_devs, &fs_uuids, list) { + int del = 1; + + if (fs_devs->opened) + continue; + if (fs_devs->seeding) + continue; + + list_for_each_entry(dev, &fs_devs->devices, dev_list) { + + if (dev == cur_dev) + continue; + if (!dev->name) + continue; + + /* + * Todo: This won't be enough. What if the same device + * comes back (with new uuid and) with its mapper path? + * But for now, this does help as mostly an admin will + * either use mapper or non mapper path throughout. + */ + rcu_read_lock(); + del = strcmp(rcu_str_deref(dev->name), + rcu_str_deref(cur_dev->name)); + rcu_read_unlock(); + if (!del) + break; + } + + if (!del) { + /* delete the stale device */ + if (fs_devs->num_devices == 1) { + btrfs_sysfs_remove_fsid(fs_devs); + list_del(&fs_devs->list); + free_fs_devices(fs_devs); + } else { + fs_devs->num_devices--; + list_del(&dev->dev_list); + rcu_string_free(dev->name); + kfree(dev); + } + break; + } + } + return; +} + /* * Add new device to list of registered devices * @@ -560,6 +616,12 @@ static noinline int device_list_add(const char *path, if (!fs_devices->opened) device->generation = found_transid; + /* + * if there is new btrfs on an already registered device, + * then remove the stale device entry. + */ + btrfs_free_stale_device(device); + *fs_devices_ret = fs_devices; return ret;