From: David Sterba <dsterba@suse.com> commit 10a3a3edc5b89a8cd095bc63495fb1e0f42047d9 upstream. A remount to a read-write filesystem is not safe when there's tree-log to be replayed. Files that could be opened until now might be affected by the changes in the tree-log. A regular mount is needed to replay the log so the filesystem presents the consistent view with the pending changes included. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/btrfs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index db4002e..6a5b16a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1857,6 +1857,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) } if (btrfs_super_log_root(fs_info->super_copy) != 0) { + btrfs_warn(fs_info, + "mount required to replay tree-log, cannot remount read-write"); ret = -EINVAL; goto restore; } -- 1.8.3