From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759975Ab3B0NKR (ORCPT ); Wed, 27 Feb 2013 08:10:17 -0500 Received: from mail4.sde.cz ([85.93.125.197]:36607 "EHLO zimbra.sde" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759835Ab3B0NKP (ORCPT ); Wed, 27 Feb 2013 08:10:15 -0500 Date: Wed, 27 Feb 2013 14:09:48 +0100 (CET) From: Milos Vyletel To: Rusty Russell Cc: Greg KH , Kay Sievers , linux-kernel@vger.kernel.org, linux-hotplug@vger.kernel.org, virtualization@lists.linux-foundation.org, mst@redhat.com Message-ID: <1972692083.62396.1361970588620.JavaMail.root@sde.cz> In-Reply-To: <87wqtuegs9.fsf@rustcorp.com.au> References: <1361473348-7660-1-git-send-email-milos.vyletel@sde.cz> <87y5ehfczy.fsf@rustcorp.com.au> <20130225221238.GA10575@kroah.com> <16100EF6-6C55-47ED-9BBB-2C3CAC8FA37A@sde.cz> <87wqtuegs9.fsf@rustcorp.com.au> Subject: Re: [PATCH] virtio-blk: emit udev event when device is resized MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [199.72.20.10] X-Mailer: Zimbra 8.0.2_GA_5569 (ZimbraWebClient - FF16 (Win)/8.0.2_GA_5569) Thread-Topic: virtio-blk: emit udev event when device is resized Thread-Index: L2+lY4veybV/otvQR4qrApeoJNdAsQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > Milos Vyletel writes: > > On Feb 25, 2013, at 5:12 PM, Greg KH wrote: > > > >> On Fri, Feb 22, 2013 at 10:14:49AM +1030, Rusty Russell wrote: > >>> Milos Vyletel writes: > >>> > >>>> When virtio-blk device is resized from host (using block_resize from > >>>> QEMU) emit > >>>> KOBJ_CHANGE uevent to notify guest about such change. This allows user > >>>> to have > >>>> custom udev rules which would take whatever action if such event occurs. > >>>> As a > >>>> proof of concept I've created simple udev rule that automatically resize > >>>> filesystem on virtio-blk device. > >>>> > >>>> ACTION=="change", KERNEL=="vd*", \ > >>>> ENV{RESIZE}=="1", \ > >>>> ENV{ID_FS_TYPE}=="ext[3-4]", \ > >>>> RUN+="/sbin/resize2fs /dev/%k" > >>>> ACTION=="change", KERNEL=="vd*", \ > >>>> ENV{RESIZE}=="1", \ > >>>> ENV{ID_FS_TYPE}=="LVM2_member", \ > >>>> RUN+="/sbin/pvresize /dev/%k" > >>> > >>> This looks fine to me, but I like to check with Greg before adding udev > >>> callouts.... Greg? > >> > >> Hm, I thought we were frowning apon running binaries from udev rules > >> these days, especially ones that might have big consequences (like > >> resizing a disk image) like this. > >> > >> Kay, am I right? > >> > >> We already emit KOBJECT_CHANGE events when block devices change, from > >> within the block core code. Why is the patch below needed instead of > >> using these events that are already generated? How are virtio block > >> devices special? > >> > >>> BTW, if this is good, it's good for stable IMHO. > >> > >> What bug does it fix? > >> > > > > It is not really a bug but it definitely is useful enhancement to have in > > stable too. I > > can imagine lots of people can benefit from this. > > But that applies to almost any enhancement :) > Good point :) > It will go in *next* merge window, not this one. > Cool, thanks. Milos