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

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

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@xxxxxxxxxxxxxx>
> CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
> CC: Wei Liu <wei.liu2@xxxxxxxxxx>
> CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
>  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.

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;
>          }
>  



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