From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932218AbcIAJNv (ORCPT ); Thu, 1 Sep 2016 05:13:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:49348 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752793AbcIAJNs (ORCPT ); Thu, 1 Sep 2016 05:13:48 -0400 Date: Thu, 01 Sep 2016 11:13:46 +0200 Message-ID: From: Takashi Iwai To: Ian Kent Cc: Al Viro , linux-fsdevel , autofs mailing list , Kernel Mailing List Subject: Re: [PATCH] autofs - use dentry flags to block walks during expire In-Reply-To: <20160901012114.6476.57874.stgit@pluto.themaw.net> References: <20160901012114.6476.57874.stgit@pluto.themaw.net> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.5 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 01 Sep 2016 03:21:14 +0200, Ian Kent wrote: > > Somewhere along the way the autofs expire operation has changed to > hold a spin lock over expired dentry selection. The autofs indirect > mount expired dentry selection is complicated and quite lengthy so > it isn't appropriate to hold a spin lock over the operation. > > Commit 47be6184 added a might_sleep() to dput() causing a BUG() > about this usage to be issued. > > But the spin lock doesn't need to be held over this check, the > autofs dentry info. flags are enough to block walks into dentrys > during the expire. > > I've left the direct mount expire as it is (for now) becuase it > is much simpler and quicker than the indirect mount expire and > adding spin lock release and re-aquires would do nothing more > than add overhead. > > Signed-off-by: Ian Kent Looks working fine, so far. Reported-and-tested-by: Takashi Iwai thanks, Takashi