[libvirt] [PATCH] qemu: make attaching disk partition to VM illegal

[Daniel Henrique Barboza]

On 9/27/19 12:11 PM, Pavel Mores wrote:
> The way in which the qemu driver generates aliases for disks involves
> ignoring the partition number part of a target dev name.  This means that
> all partitions of a block device and the device itself all end up with the
> same alias.  If multiple such disks are specified in XML, the resulting
> name clash makes qemu invocation fail.
>
> Since attaching partitions to qemu VMs doesn't seem to make much sense
> anyway, disallow partitions in target specifications altogether.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1346265
>
> Signed-off-by: Pavel Mores <pmores at redhat.com>
> ---

I have a small nit below, but patch seems fine.

Unfortunately it breaks 'make check' in my machine, in virschematest:


297 281) Checking chardev-reconnect-generated-path.xml against 
domain.rng  ... OK
  298 282) Checking disk-attaching-partition-invalid.xml against 
domain.rng  ... FAILED
  299 283) Checking iommu-smmuv3.xml against 
domain.rng                      ... OK



>   src/qemu/qemu_domain.c                        | 10 +++++++
>   .../disk-attaching-partition-invalid.xml      | 27 +++++++++++++++++++
>   tests/qemuxml2argvtest.c                      |  1 +
>   3 files changed, 38 insertions(+)
>   create mode 100644 tests/qemuxml2argvdata/disk-attaching-partition-invalid.xml
>
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index e8e895d9aa..d03f3bed5f 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -5880,6 +5880,8 @@ qemuDomainDeviceDefValidateDisk(const virDomainDiskDef *disk,
>   {
>       const char *driverName = virDomainDiskGetDriver(disk);
>       virStorageSourcePtr n;
> +    int idx;
> +    int partition;
>   
>       if (disk->src->shared && !disk->src->readonly &&
>           !qemuBlockStorageSourceSupportsConcurrentAccess(disk->src)) {
> @@ -5948,6 +5950,14 @@ qemuDomainDeviceDefValidateDisk(const virDomainDiskDef *disk,
>           return -1;
>       }
>   
> +    int result = virDiskNameParse(disk->dst, &idx, &partition);
> +    if (result != 0 || partition != 0) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                       _("can't attach disk partition '%s', please attach whole disk instead"),
> +                       disk->dst);

Break line to keep the line <= 80 chars plz.

> +        return -1;
> +    }
> +
>       for (n = disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
>           if (qemuDomainValidateStorageSource(n, qemuCaps) < 0)
>               return -1;
> diff --git a/tests/qemuxml2argvdata/disk-attaching-partition-invalid.xml b/tests/qemuxml2argvdata/disk-attaching-partition-invalid.xml
> new file mode 100644
> index 0000000000..591819fbb6
> --- /dev/null
> +++ b/tests/qemuxml2argvdata/disk-attaching-partition-invalid.xml
> @@ -0,0 +1,27 @@
> +<domain type='qemu'>
> +  <name>QEMUGuest1</name>
> +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> +  <memory unit='KiB'>219100</memory>
> +  <currentMemory unit='KiB'>219100</currentMemory>
> +  <vcpu placement='static'>1</vcpu>
> +  <os>
> +    <type arch='i686' machine='pc'>hvm</type>
> +    <boot dev='hd'/>
> +  </os>
> +  <clock offset='utc'/>
> +  <on_poweroff>destroy</on_poweroff>
> +  <on_reboot>restart</on_reboot>
> +  <on_crash>destroy</on_crash>
> +  <devices>
> +    <emulator>/usr/bin/qemu-system-i686</emulator>
> +    <disk type='file' device='disk'>
> +      <driver name='qemu' type='raw'/>
> +      <source file='/export/vmimages/1.raw'/>
> +      <target dev='vdb1' bus='virtio'/>
> +    </disk>
> +    <controller type='usb' index='0'/>
> +    <controller type='ide' index='0'/>
> +    <controller type='pci' index='0' model='pci-root'/>
> +    <memballoon model='virtio'/>
> +  </devices>
> +</domain>
> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> index 5bbac1c8b8..b54b4bbf35 100644
> --- a/tests/qemuxml2argvtest.c
> +++ b/tests/qemuxml2argvtest.c
> @@ -1097,6 +1097,7 @@ mymain(void)
>       DO_TEST("disk-no-boot", NONE);
>       DO_TEST_PARSE_ERROR("disk-device-lun-type-invalid",
>                           QEMU_CAPS_VIRTIO_SCSI);
> +    DO_TEST_CAPS_LATEST_PARSE_ERROR("disk-attaching-partition-invalid");
>       DO_TEST_FAILURE("disk-usb-nosupport", NONE);
>       DO_TEST("disk-usb-device",
>               QEMU_CAPS_DEVICE_USB_STORAGE);