| Message ID | 20120802013242.GA18298@tuon.disenchant.local |
|---|---|
| State | New |
| Headers | show |
On Thu, Aug 02, 2012 at 11:02:42AM +0930, Kevin Shanahan wrote: > Set the block driver read_only flag for cdrom devices so that > qmp_change_blockdev does not attempt to open cdrom files in read-write > mode when changing media. Hrm, this fixes my simple test case using the kvm monitor directly but changing media via libvirt still has the same issue (fails for RO files, succeeds for writable files). $ virsh attach-disk --type cdrom --mode readonly test1 /srv/kvm/iso/ubuntu-12.04-server-amd64.iso hdc error: Failed to attach disk error: internal error unable to execute QEMU command 'change': Could not open '/srv/kvm/iso/ubuntu-12.04-server-amd64.iso' I'll keep looking into it. Cheers, Kevin.
On Thu, Aug 02, 2012 at 11:46:13AM +0930, Kevin Shanahan wrote: > On Thu, Aug 02, 2012 at 11:02:42AM +0930, Kevin Shanahan wrote: > > Set the block driver read_only flag for cdrom devices so that > > qmp_change_blockdev does not attempt to open cdrom files in read-write > > mode when changing media. > > Hrm, this fixes my simple test case using the kvm monitor directly but > changing media via libvirt still has the same issue (fails for RO > files, succeeds for writable files). > > $ virsh attach-disk --type cdrom --mode readonly test1 /srv/kvm/iso/ubuntu-12.04-server-amd64.iso hdc > error: Failed to attach disk > error: internal error unable to execute QEMU command 'change': Could not open '/srv/kvm/iso/ubuntu-12.04-server-amd64.iso' > > I'll keep looking into it. In the libvirt case, it seems libvirt is failing to add media=cdrom to the commandline, so in this case qemu is defaulting to media=disk and my proposed fix has no effect. Diving into libvirt now to see why no media=disk is getting added... Common test case has this xml (generated by virt-install): <disk type='block' device='cdrom'> <driver name='qemu' type='raw'/> <target dev='hdc' bus='ide'/> <readonly/> <alias name='ide0-1-0'/> <address type='drive' controller='0' bus='1' target='0' unit='0'/> </disk> > Cheers, > Kevin.
diff -urN qemu-kvm-1.1.1.orig/blockdev.c qemu-kvm-1.1.1/blockdev.c --- qemu-kvm-1.1.1.orig/blockdev.c 2012-07-16 17:22:03.000000000 +0930 +++ qemu-kvm-1.1.1/blockdev.c 2012-08-02 10:28:40.000000000 +0930 @@ -565,6 +565,7 @@ break; case MEDIA_CDROM: dinfo->media_cd = 1; + dinfo->bdrv->read_only = 1; break; } break;
Set the block driver read_only flag for cdrom devices so that qmp_change_blockdev does not attempt to open cdrom files in read-write mode when changing media. Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net> --- Proposed fix for https://bugs.launchpad.net/qemu/+bug/1027525