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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 90339C3B19F for ; Fri, 14 Feb 2020 16:10:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69BBA222C2 for ; Fri, 14 Feb 2020 16:10:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696604; bh=sr4AxBpVkrWKUM0/W5gOFoSBI4JuE8Ie0711+bXurxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=U3ETMdq7DdlcHxUL3bvKLN2reMX2KBivfRhLtnDEl8FNXP879xwCSzgq7dluTQXTs SY1kfDaYcGjmPdrEZzX3xeLzHbFVheSwPgTJk0lt4ZfACb7tXzdsuE8ZLKsxXReJ5F T+xUtB42JuV4RrZoRzrgi+Pb0l8fCH55aPQxlSNs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391390AbgBNQKD (ORCPT ); Fri, 14 Feb 2020 11:10:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:35248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391387AbgBNQKC (ORCPT ); Fri, 14 Feb 2020 11:10:02 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5AC2A24694; Fri, 14 Feb 2020 16:10:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696601; bh=sr4AxBpVkrWKUM0/W5gOFoSBI4JuE8Ie0711+bXurxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xHl8XPhoriTDP3xTLY3Gab4n+dMBZXslU9PQaR91/DQ4HQmloArd2V6ybMc37i/Z1 AfnWPpHzRF8Vn2G0UZ1x6V0NjpKIdHQgWyvAqxVLkEn3DwWjbUb1qSr4JrUObwsSyD WD75wTG+nkFN+CKl0ihlCXNkthnkKQbAsMdKh+8M= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nikolay Borisov , Su Yue , Josef Bacik , David Sterba , Sasha Levin , linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 386/459] btrfs: Fix split-brain handling when changing FSID to metadata uuid Date: Fri, 14 Feb 2020 11:00:36 -0500 Message-Id: <20200214160149.11681-386-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Nikolay Borisov [ Upstream commit 1362089d2ad7e20d16371b39d3c11990d4ec23e4 ] Current code doesn't correctly handle the situation which arises when a file system that has METADATA_UUID_INCOMPAT flag set and has its FSID changed to the one in metadata uuid. This causes the incompat flag to disappear. In case of a power failure we could end up in a situation where part of the disks in a multi-disk filesystem are correctly reverted to METADATA_UUID_INCOMPAT flag unset state, while others have METADATA_UUID_INCOMPAT set and CHANGING_FSID_V2_IN_PROGRESS. This patch corrects the behavior required to handle the case where a disk of the second type is scanned first, creating the necessary btrfs_fs_devices. Subsequently, when a disk which has already completed the transition is scanned it should overwrite the data in btrfs_fs_devices. Reported-by: Su Yue Reviewed-by: Josef Bacik Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/volumes.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 9ab3ae5df3005..3e64f49c394b8 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -907,6 +907,32 @@ static struct btrfs_fs_devices *find_fsid_changed( return NULL; } + +static struct btrfs_fs_devices *find_fsid_reverted_metadata( + struct btrfs_super_block *disk_super) +{ + struct btrfs_fs_devices *fs_devices; + + /* + * Handle the case where the scanned device is part of an fs whose last + * metadata UUID change reverted it to the original FSID. At the same + * time * fs_devices was first created by another constitutent device + * which didn't fully observe the operation. This results in an + * btrfs_fs_devices created with metadata/fsid different AND + * btrfs_fs_devices::fsid_change set AND the metadata_uuid of the + * fs_devices equal to the FSID of the disk. + */ + list_for_each_entry(fs_devices, &fs_uuids, fs_list) { + if (memcmp(fs_devices->fsid, fs_devices->metadata_uuid, + BTRFS_FSID_SIZE) != 0 && + memcmp(fs_devices->metadata_uuid, disk_super->fsid, + BTRFS_FSID_SIZE) == 0 && + fs_devices->fsid_change) + return fs_devices; + } + + return NULL; +} /* * Add new device to list of registered devices * @@ -946,7 +972,9 @@ static noinline struct btrfs_device *device_list_add(const char *path, fs_devices = find_fsid(disk_super->fsid, disk_super->metadata_uuid); } else { - fs_devices = find_fsid(disk_super->fsid, NULL); + fs_devices = find_fsid_reverted_metadata(disk_super); + if (!fs_devices) + fs_devices = find_fsid(disk_super->fsid, NULL); } @@ -976,12 +1004,18 @@ static noinline struct btrfs_device *device_list_add(const char *path, * a device which had the CHANGING_FSID_V2 flag then replace the * metadata_uuid/fsid values of the fs_devices. */ - if (has_metadata_uuid && fs_devices->fsid_change && + if (fs_devices->fsid_change && found_transid > fs_devices->latest_generation) { memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE); - memcpy(fs_devices->metadata_uuid, - disk_super->metadata_uuid, BTRFS_FSID_SIZE); + + if (has_metadata_uuid) + memcpy(fs_devices->metadata_uuid, + disk_super->metadata_uuid, + BTRFS_FSID_SIZE); + else + memcpy(fs_devices->metadata_uuid, + disk_super->fsid, BTRFS_FSID_SIZE); fs_devices->fsid_change = false; } -- 2.20.1