From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759639Ab3BYOzZ (ORCPT ); Mon, 25 Feb 2013 09:55:25 -0500 Received: from mail4.sde.cz ([85.93.125.197]:41162 "EHLO zimbra.sde" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759541Ab3BYOzV (ORCPT ); Mon, 25 Feb 2013 09:55:21 -0500 Date: Mon, 25 Feb 2013 15:54:56 +0100 (CET) From: Milos Vyletel To: Asias He Cc: linux-kernel@vger.kernel.org, mst@redhat.com, virtualization@lists.linux-foundation.org Message-ID: <2042715078.26369.1361804096841.JavaMail.root@sde.cz> In-Reply-To: <512B1637.5060107@redhat.com> References: <1361473348-7660-1-git-send-email-milos.vyletel@sde.cz> <512B1637.5060107@redhat.com> 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: l+tZXbJ3KAsIhlpQ/yFFZvZIRcxm/A== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > On 02/22/2013 03:02 AM, Milos Vyletel wrote: > > 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" > > > > Signed-off-by: Milos Vyletel > > --- > > drivers/block/virtio_blk.c | 3 +++ > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > > index 8ad21a2..5990382 100644 > > --- a/drivers/block/virtio_blk.c > > +++ b/drivers/block/virtio_blk.c > > @@ -539,6 +539,8 @@ static void virtblk_config_changed_work(struct > > work_struct *work) > > struct virtio_device *vdev = vblk->vdev; > > struct request_queue *q = vblk->disk->queue; > > char cap_str_2[10], cap_str_10[10]; > > + char event[] = "RESIZE=1"; > > + char *envp[] = { event, NULL }; > > event is not used again. Why not just > > char *envp[] = { "RESIZE=1", NULL }; > You're right. This works too. I was looking at other modules in kernel how they do it and this was commonly used. Take a look at block/genhd.c media_change_notify_thread() function which does similar thing. > > > u64 capacity, size; > > > > mutex_lock(&vblk->config_lock); > > @@ -568,6 +570,7 @@ static void virtblk_config_changed_work(struct > > work_struct *work) > > > > set_capacity(vblk->disk, capacity); > > revalidate_disk(vblk->disk); > > + kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); > > done: > > mutex_unlock(&vblk->config_lock); > > } > > > > I tried the following with your automatically resize udev rules. > > (qemu) block_resize vd0 500 > Check the fs size in guest, it is 500Mb > > (qemu) block_resize vd0 1200 > Check the fs size in guest, it is still 500Mb > > Can you try resizing multiple times? Does it work? Yep, works for me. After each block_resize call I get udev event. I was running udevadm monitor at that time. I've also tried running udevd in debug mode and even if I try to bump size twice in a row I get two separate udev events and resize2fs is triggered. [root@host ~]# lvresize -f -L +100M /dev/vgguests/evd2 && \ virsh blockresize resize vdb 1 && \ lvresize -f -L +100M /dev/vgguests/evd2 && \ virsh blockresize resize vdb 1 Rounding size to boundary between physical extents: 128.00 MiB Extending logical volume evd2 to 31.38 GiB Logical volume evd2 successfully resized Block device 'vdb' is resized Rounding size to boundary between physical extents: 128.00 MiB Extending logical volume evd2 to 31.50 GiB Logical volume evd2 successfully resized Block device 'vdb' is resized On guest I get this (from udevd --debug) ... 1361804003.724025 [4438] util_run_program: '/sbin/resize2fs /dev/vdb' started 1361804003.725215 [4438] util_run_program: '/sbin/resize2fs' (stderr) 'resize2fs 1.41.12 (17-May-2010)' 1361804004.129329 [4437] event_queue_insert: seq 2073 queued, 'change' 'block' 1361804006.577235 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'Filesystem at /dev/vdb is mounted on /mnt/backup; on-line resizing required' 1361804006.577251 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'old desc_blocks = 2, new_desc_blocks = 2' 1361804006.577254 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'Performing an on-line resize of /dev/vdb to 8224768 (4k) blocks.' 1361804006.577257 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'The filesystem on /dev/vdb is now 8224768 blocks long.' 1361804006.577260 [4438] util_run_program: '/sbin/resize2fs' (stdout) '' 1361804006.577544 [4438] util_run_program: '/sbin/resize2fs /dev/vdb' returned with exitcode 0 ... 1361804006.702659 [4438] util_run_program: '/sbin/resize2fs /dev/vdb' started 1361804006.703841 [4438] util_run_program: '/sbin/resize2fs' (stderr) 'resize2fs 1.41.12 (17-May-2010)' 1361804009.343332 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'Filesystem at /dev/vdb is mounted on /mnt/backup; on-line resizing required' 1361804009.343351 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'old desc_blocks = 2, new_desc_blocks = 2' 1361804009.343356 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'Performing an on-line resize of /dev/vdb to 8257536 (4k) blocks.' 1361804009.343362 [4438] util_run_program: '/sbin/resize2fs' (stdout) 'The filesystem on /dev/vdb is now 8257536 blocks long.' 1361804009.343367 [4438] util_run_program: '/sbin/resize2fs' (stdout) '' 1361804009.343727 [4438] util_run_program: '/sbin/resize2fs /dev/vdb' returned with exitcode 0 1361804009.343740 [4438] udev_watch_begin: adding watch on '/dev/vdb' Milos