From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 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" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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