[libvirt] [PATCH v3] qemu-migration: Disallow migration of read only disk

[Boris Fiuczynski]

On 10/12/2016 10:13 AM, Peter Krempa wrote:
> On Mon, Sep 26, 2016 at 13:16:00 -0400, Corey S. McQuay wrote:
>> Currently Libvirt allows attempts to migrate read only disks. Qemu cannot handle this as read only
>> disks cannot be written to on the destination system. The end result is a cryptic error message
>> and a failed migration.
>>
>> This patch causes migration to fail earlier and provides a meaningful error message stating that
>> migrating read only disks is not supported.
>>
>> Signed-off-by: Corey S. McQuay <csmcquay at linux.vnet.ibm.com>
>> Reviewed-by: Jason J. Herne <jjherne at linux.vnet.ibm.com>
>> Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
>> ---
>>  src/qemu/qemu_migration.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
>> index e451ef6..c8fb7ec 100644
>> --- a/src/qemu/qemu_migration.c
>> +++ b/src/qemu/qemu_migration.c
>> @@ -1764,6 +1764,12 @@ qemuMigrationStartNBDServer(virQEMUDriverPtr driver,
>>          /* check whether disk should be migrated */
>>          if (!qemuMigrateDisk(disk, nmigrate_disks, migrate_disks))
>>              continue;
>> +
>> +        if (disk->src->readonly) {
>> +            virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>> +                        _("Cannot migrate read-only disk %s"), disk->dst);
>
> This is misaligned.
>
>> +            goto cleanup;
>> +        }
>>
>>          VIR_FREE(diskAlias);
>>          if (!(diskAlias = qemuAliasFromDisk(disk)))
>
> This patch fails syntax check due to trailing whitespace:
>
> trailing_blank
> src/qemu/qemu_migration.c:1767:
> src/qemu/qemu_migration.c:1769:            virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> maint.mk: found trailing blank(s)
> make: *** [maint.mk:748: sc_trailing_blank] Error 1
>
> Please make sure you run "make check" and "make syntax-check" prior to
> submitting patches.
>
> I'll adjust the mistakes and push this as the patch is rather trivial.

Thanks for adjusting the syntax errors and pushing the patch.
I enjoyed reading the "rather trivial" comment as this is version 3 of 
the patch. Isn't it good if things become rather trivial? ;-)


-- 
Mit freundlichen Grüßen/Kind regards
    Boris Fiuczynski

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