Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752215AbdGDLtS (ORCPT ); Tue, 4 Jul 2017 07:49:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:51600 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752051AbdGDLtQ (ORCPT ); Tue, 4 Jul 2017 07:49:16 -0400 From: Aleksa Sarai To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, Aleksa Sarai , stable@vger.kernel.org, Jeff Mahoney Subject: [PATCH] btrfs: resume qgroup rescan on rw remount Date: Tue, 4 Jul 2017 21:49:06 +1000 Message-Id: <20170704114906.8419-1-asarai@suse.de> X-Mailer: git-send-email 2.13.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1307 Lines: 34 Several distributions mount the "proper root" as ro during initrd and then remount it as rw before pivot_root(2). Thus, if a rescan had been aborted by a previous shutdown, the rescan would never be resumed. This issue would manifest itself as several btrfs ioctl(2)s causing the entire machine to hang when btrfs_qgroup_wait_for_completion was hit (due to the fs_info->qgroup_rescan_running flag being set but the rescan itself not being resumed). Notably, Docker's btrfs storage driver makes regular use of BTRFS_QUOTA_CTL_DISABLE and BTRFS_IOC_QUOTA_RESCAN_WAIT (causing this problem to be manifested on boot for some machines). Cc: # v3.11+ Cc: Jeff Mahoney Fixes: b382a324b60f ("Btrfs: fix qgroup rescan resume on mount") Signed-off-by: Aleksa Sarai --- fs/btrfs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 6346876c97ea..ff6690389343 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1821,6 +1821,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) goto restore; } + btrfs_qgroup_rescan_resume(fs_info); + if (!fs_info->uuid_root) { btrfs_info(fs_info, "creating UUID tree"); ret = btrfs_create_uuid_tree(fs_info); -- 2.13.2