Hi, This list seem to be most appropriate place to ask this question since it's QEMU related and virtio-blk maintainers are here as well.
I'm doing some work with online resizing of guest's block device on LVM. What I do is call lvresize to expand logical volume itself and virsh blockresize to notify guest about this change. Besides the fact that I needed to patch kernel to get this working on mounted partitions(BZ 906050) everything works just fine. Now that I've had this part successfully tested I wanted to make a script that will be triggered by udev whenever particular device is changed. I assumed that after capacity change virtio_blk driver would emit udev event but that's not the case. I'm able to see one on host but not on guest. [root@host ~]# 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 15.00 GiB Logical volume evd2 successfully resized Block device 'vdb' is resized [root@host ~]# udevadm monitor ... KERNEL[1361292279.619233] change /devices/virtual/block/dm-9 (block) UDEV [1361292279.736012] change /devices/virtual/block/dm-9 (block) ... I was looking at the virtblk_config_changed_work function in RHEL6.3 kernel's drivers/block/virtio_blk.c which I believe is the function handling blockresize and it does not look like it tries to emit any kobject uevent. Before I jump into patching kernel my question is whether it makes sense to have such uevent? I surely can use a way how to detect capacity change from userspace. Thanks, Milos
