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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 38D88C433EF for ; Thu, 14 Jun 2018 11:00:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB193208D9 for ; Thu, 14 Jun 2018 11:00:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="TNtqjj2y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB193208D9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755110AbeFNLAL (ORCPT ); Thu, 14 Jun 2018 07:00:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:40060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754906AbeFNLAK (ORCPT ); Thu, 14 Jun 2018 07:00:10 -0400 Received: from tleilax.poochiereds.net (cpe-71-70-156-158.nc.res.rr.com [71.70.156.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DE371208D4; Thu, 14 Jun 2018 11:00:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528974010; bh=txTqgVC2CboIHthV54PHG96RQBQFm2lzl/gGKPScroo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=TNtqjj2y5Lh6t2TDRyF5GZ5cZ2Dla1h5XfudCiSZn4FNxt3EcsLFaSrKHF9sedO8V pZUjmSvi6Yuszn/2biWFOXLcDSkZHTAMR2kPjJHEzQl+9AWuRItLWI+T725q6UAzAV oJrvzZy93MV7mTULF1OzWz7DDOECnTHBgR6JFagk= Message-ID: Subject: Re: [PATCH 2/2] fs/lock: show locks taken by processes from another pidns From: Jeff Layton To: Konstantin Khorenko , Kirill Gorkunov , Andrey Vagin , Benjamin Coddington , "J. Bruce Fields" , Alexander Viro Cc: Vasily Averin , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Nikolay Borisov Date: Thu, 14 Jun 2018 07:00:07 -0400 In-Reply-To: <20180608142712.32460-3-khorenko@virtuozzo.com> References: <20180608142712.32460-1-khorenko@virtuozzo.com> <20180608142712.32460-3-khorenko@virtuozzo.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.2 (3.28.2-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2018-06-08 at 17:27 +0300, Konstantin Khorenko wrote: > Currently if we face a lock taken by a process invisible in the current > pidns we skip the lock completely, but this > > 1) makes the output not that nice > (root@vz7)/: cat /proc/${PID_A2}/fdinfo/3 > pos: 4 > flags: 02100002 > mnt_id: 257 > lock: (root@vz7)/: > > 2) makes it more difficult to debug issues with leaked flocks > if you get error on lock, but don't see any locks in /proc/$id/fdinfo/$file > > Let's show information about such locks again as previously, but > show zero in the owner pid field. > > After the patch: > =============== > (root@vz7)/:cat /proc/${PID_A2}/fdinfo/3 > pos: 4 > flags: 02100002 > mnt_id: 295 > lock: 1: FLOCK ADVISORY WRITE 0 b6:f8a61:529946 0 EOF > > Fixes: 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific l_pid for remote locks") > Signed-off-by: Konstantin Khorenko > --- > fs/locks.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/fs/locks.c b/fs/locks.c > index bfee5b7f2862..e533623e2e99 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -2633,12 +2633,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, > > fl_pid = locks_translate_pid(fl, proc_pidns); > /* > - * If there isn't a fl_pid don't display who is waiting on > - * the lock if we are called from locks_show, or if we are > - * called from __show_fd_info - skip lock entirely > + * If lock owner is dead (and pid is freed) or not visible in current > + * pidns, zero is shown as a pid value. Check lock info from > + * init_pid_ns to get saved lock pid value. > */ > - if (fl_pid == 0) > - return; > > if (fl->fl_file != NULL) > inode = locks_inode(fl->fl_file); (cc'ing Nickolay) As Andrey points out, this behavior was originally added in commit d67fd44f697d to address performance issues when there are a lot of locks held by tasks in other namespaces. Will allowing this code to show these again cause a problem there? -- Jeff Layton