From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karel Zak Subject: Re: [dm-devel] linux-next - WARNING: at fs/block_dev.c:824 bd_link_disk_holder+0x92/0x1ac() Date: Fri, 14 Jan 2011 16:07:36 +0100 Message-ID: <20110114150736.GJ16523@nb.net.home> References: <20110113131216.GF30719@htj.dyndns.org> <20110113132637.GH16523@nb.net.home> <20110113133722.GG30719@htj.dyndns.org> <4D2F04FF.1070309@redhat.com> <20110113141107.GI30719@htj.dyndns.org> <4D2F0B6A.6010201@redhat.com> <20110113155955.GI16523@nb.net.home> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Tejun Heo , Milan Broz , device-mapper development , "Jun'ichi Nomura" , Valdis.Kletnieks@vt.edu, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, Alexander Viro , linux-fsdevel@vger.kernel.org To: Kay Sievers Return-path: Received: from mx1.redhat.com ([209.132.183.28]:29564 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751611Ab1ANPHr (ORCPT ); Fri, 14 Jan 2011 10:07:47 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Jan 13, 2011 at 05:10:02PM +0100, Kay Sievers wrote: > On Thu, Jan 13, 2011 at 16:59, Karel Zak wrote: > > On Thu, Jan 13, 2011 at 03:43:38PM +0100, Kay Sievers wrote: > >> On Thu, Jan 13, 2011 at 15:30, Tejun Heo wrote: > >> > On Thu, Jan 13, 2011 at 3:25 PM, Milan Broz w= rote: > >> >> Maybe, but this was not invented in DM/MD camp:-) > >> >> Probably Kay or Greg can answer why it was done this way? > >> > >> It's not from Greg or Kay. It just appeared some day in the contex= t of dm. :) > >> > >> And yes, symlinks *look* nice and simple for the outside, but they= are > >> not, and have all sorts of problems like non-atomic updates, make = it > > > > =C2=A0Sounds like sysfs implementation problem, right? >=20 > It's a normal multi-file problem. It can by-definition not be atomic > without doing really weird locking things. BTW, lsblk(8) and libblkid don't depend on the fact that slaves/holder= s=20 files are symlinks. =20 The important thing is the filename (/sys/block/.../slaves/)=20 only. We don't follow the symlinks and we don't use readlink() there. =20 It means that you can replace the symlinks with regular files where in the file contents is for example maj:min, etc. Karel --=20 Karel Zak http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html