[libvirt] [PATCH 2/2] qemu: Forbid migration of machines with I/O errors

[Peter Krempa]

On 06/11/13 14:05, Michal Privoznik wrote:
> On 11.06.2013 11:49, Peter Krempa wrote:
>> Such machine can't be successuflly migrated unles the I/O error has
>> recovered and might lead to data corruption. Forbid this kind of
>> migration.
>> ---
>>   src/qemu/qemu_migration.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
>> index 8e57521..97daaa0 100644
>> --- a/src/qemu/qemu_migration.c
>> +++ b/src/qemu/qemu_migration.c
>> @@ -1423,6 +1423,7 @@ qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm,
>>                          virDomainDefPtr def, bool remote)
>>   {
>>       int nsnapshots;
>> +    int pauseReason;
>>       bool forbid;
>>       int i;
>>
>> @@ -1445,6 +1446,15 @@ qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm,
>>                                  nsnapshots);
>>                   return false;
>>               }
>> +
>> +            /* cancel migration if disk I/O error is emitted while migrating */
>> +            if (virDomainObjGetState(vm, &pauseReason) == VIR_DOMAIN_PAUSED &&
>> +                pauseReason == VIR_DOMAIN_PAUSED_IOERROR) {
>> +                virReportError(VIR_ERR_OPERATION_INVALID, "%s",
>> +                               _("cannot migrate domain with I/O error"));
>> +                return false;
>> +            }
>> +
>>           }
>>
>>           if (virDomainHasDiskMirror(vm)) {
>>
>
> Do we want to document this behaviour change?

How about:

diff --git a/src/libvirt.c b/src/libvirt.c
index 620dbdd..6413a1e 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -5809,41 +5809,42 @@ error:
   * guest ABI,
   *
   * If a hypervisor supports renaming domains during migration,
   * the dname parameter specifies the new name for the domain.
   * Setting dname to NULL keeps the domain name the same.  If domain
   * renaming is not supported by the hypervisor, dname must be NULL or
   * else an error will be returned.
   *
   * The maximum bandwidth (in MiB/s) that will be used to do migration
   * can be specified with the bandwidth parameter.  If set to 0,
   * libvirt will choose a suitable default.  Some hypervisors do
   * not support this feature and will return an error if bandwidth
   * is not 0.
   *
   * To see which features are supported by the current hypervisor,
   * see virConnectGetCapabilities, /capabilities/host/migration_features.
   *
   * There are many limitations on migration imposed by the underlying
   * technology - for example it may not be possible to migrate between
   * different processors even with the same architecture, or between
- * different types of hypervisor.
+ * different types of hypervisor. Migration of domains that encountered
+ * errors may not be possible.
   *
   * Returns 0 if the migration succeeded, -1 upon error.
   */
  int
  virDomainMigrateToURI2(virDomainPtr domain,
                         const char *dconnuri,
                         const char *miguri,
                         const char *dxml,
                         unsigned long flags,
                         const char *dname,
                         unsigned long bandwidth)
  {
      VIR_DOMAIN_DEBUG(domain, "dconnuri=%s, miguri=%s, dxml=%s, "
                       "flags=%lx, dname=%s, bandwidth=%lu",
                       NULLSTR(dconnuri), NULLSTR(miguri), NULLSTR(dxml),
                       flags, NULLSTR(dname), bandwidth);

      virResetLastError();

      /* First checkout the source */