----- Original Message ----- > On 02/25/2013 10:54 PM, Milos Vyletel wrote: > > ----- 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 <milos.vyletel@xxxxxx> > >>> --- > >>> 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. > > Well, which kernel version are you looking at. > media_change_notify_thread() is gone back in 2010. See commit: dddd9dc340. > Oh, you're right. I was looking at the rhel 6.3 kernel (2.6.32-279.19.1.el6) before I switched to upstream branch and did the changes. Sorry about the confusion. Milos > >> > >>> 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. > > Turned on the debug info and looked into it again. It works for me now > and the udev event is seen. > > Tested-by: Asias He <asias@xxxxxxxxxx> > > > [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 > > > > > -- > Asias > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization