From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759911Ab3B0BwM (ORCPT ); Tue, 26 Feb 2013 20:52:12 -0500 Received: from ozlabs.org ([203.10.76.45]:55780 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759240Ab3B0BwJ (ORCPT ); Tue, 26 Feb 2013 20:52:09 -0500 From: Rusty Russell To: Milos Vyletel , Greg KH Cc: Kay Sievers , linux-kernel@vger.kernel.org, linux-hotplug@vger.kernel.org, virtualization@lists.linux-foundation.org, mst@redhat.com Subject: Re: [PATCH] virtio-blk: emit udev event when device is resized In-Reply-To: <16100EF6-6C55-47ED-9BBB-2C3CAC8FA37A@sde.cz> 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> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Wed, 27 Feb 2013 11:04:14 +1030 Message-ID: <87wqtuegs9.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 :) It will go in *next* merge window, not this one. Thanks, Rusty.