Re: [PATCH v3 COLOPre 07/26] libxc/restore: fix error handle of process_record

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 06/30/2015 12:07 AM, Ian Campbell wrote:
> On Thu, 2015-06-25 at 14:25 +0800, Yang Hongyang wrote:
>
> ITYM "handling" in the subject. And perhaps "change" rather than "fix"?
>
>> If the err is RECORD_NOT_PROCESSED, and it is an optional record,
>> restore will still fail. There're two options to fix this,
>>    a, setting rc to 0 when it is an optional record.
>>    b, do the error handling in the caller.
>> We choose b because:
>> There will be another error type in COLO, which indicates a failover,
>> that needs to be handled in restore(), so moving the error handling out
>> to make the logic clearer...Otherwise, in process_record,
>> RECORD_NOT_PROCESSED is handled, and in restore another error type
>> returned from process_record is handled.
>>
>> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
>> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
>> CC: Wei Liu <wei.liu2@citrix.com>
>> CC: Andrew Cooper <andrew.cooper3@citrix.com>
>> ---
>>   tools/libxc/xc_sr_restore.c | 28 ++++++++++++++--------------
>>   1 file changed, 14 insertions(+), 14 deletions(-)
>>
>> diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
>> index fd45775..d5645e0 100644
>> --- a/tools/libxc/xc_sr_restore.c
>> +++ b/tools/libxc/xc_sr_restore.c
>> @@ -569,19 +569,6 @@ static int process_record(struct xc_sr_context *ctx, struct xc_sr_record *rec)
>>       free(rec->data);
>>       rec->data = NULL;
>>
>> -    if ( rc == RECORD_NOT_PROCESSED )
>> -    {
>> -        if ( rec->type & REC_TYPE_OPTIONAL )
>> -            DPRINTF("Ignoring optional record %#x (%s)",
>> -                    rec->type, rec_type_to_str(rec->type));
>> -        else
>> -        {
>> -            ERROR("Mandatory record %#x (%s) not handled",
>> -                  rec->type, rec_type_to_str(rec->type));
>> -            rc = -1;
>> -        }
>> -    }
>> -
>>       return rc;
>>   }
>>
>> @@ -669,7 +656,20 @@ static int restore(struct xc_sr_context *ctx)
>
> There is a second caller of process_record in handle_checkpoint, so this
> change will result in a change of behaviour for that case, I think.

Ah, seems I missed the other caller, good catch, and I will fix it in the
next version.

>
> If that is intentional then it ought to be mentioned in the commit log,
> since otherwise it looks a lot like this change is supposed to result in
> no overall difference.
>
> Ian.
>
>
>>           else
>>           {
>>               rc = process_record(ctx, &rec);
>> -            if ( rc )
>> +            if ( rc == RECORD_NOT_PROCESSED )
>> +            {
>> +                if ( rec.type & REC_TYPE_OPTIONAL )
>> +                    DPRINTF("Ignoring optional record %#x (%s)",
>> +                            rec.type, rec_type_to_str(rec.type));
>> +                else
>> +                {
>> +                    ERROR("Mandatory record %#x (%s) not handled",
>> +                          rec.type, rec_type_to_str(rec.type));
>> +                    rc = -1;
>> +                    goto err;
>> +                }
>> +            }
>> +            else if ( rc )
>>                   goto err;
>>           }
>>
>
>
> .
>

-- 
Thanks,
Yang.