Return-Path: Received: from zeniv.linux.org.uk ([195.92.253.2]:46982 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932146AbcHKCT1 (ORCPT ); Wed, 10 Aug 2016 22:19:27 -0400 Date: Thu, 11 Aug 2016 03:19:09 +0100 From: Al Viro To: Josef Bacik Cc: Linus Torvalds , kernel test robot , Chris Mason , David Sterba , "J. Bruce Fields" , LKML , LKP , linux-btrfs , Linux NFS Mailing List Subject: Re: [lkp] [nfsd] b44061d0b9: BUG: Dentry ffff880027d7c540{i=1846f,n=0a} still in use (1) [unmount of btrfs vda] Message-ID: <20160811021909.GR2356@ZenIV.linux.org.uk> References: <20160810053947.GG21941@yexl-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Aug 10, 2016 at 02:46:27PM -0400, Josef Bacik wrote: > On 08/10/2016 02:25 PM, Linus Torvalds wrote: > > On Wed, Aug 10, 2016 at 11:22 AM, Josef Bacik wrote: > > > On 08/10/2016 02:06 PM, Linus Torvalds wrote: > > > > > > > > More information in the original email on lkml. > > > > > > I'm not subscribed to lkml and for some reason I can't find the original > > > email in any of the lkml/linux-nfs archives. Could you forward more of the > > > details? > > > > Done. > > > > So my naive fix would be something like this > > > From: Josef Bacik > Date: Wed, 10 Aug 2016 14:43:08 -0400 > Subject: [PATCH] nfsd: fix dentry refcounting problem > > b44061d0b9 introduced a dentry ref counting bug, previously we were grabbing one > ref to dchild in nfsd_create(), but with the creation of nfsd_create_locked() we > have a ref for dchild from the lookup in nfsd_create(), and then another ref in > nfsd_create_locked(). The ref from the lookup in nfsd_create() is never dropped > and results in dentries still in use at unmount. > > Signed-off-by: Josef Bacik [sorry, had been off-line since yesterday] Patch looks sane; feel free to slap Acked-by: Al Viro on it. I think it should go through nfsd tree.