Re: [Qemu-devel] [PATCH 06/11] snapshot: distinguish id and name in snapshot delete

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013-6-11 17:25, Stefan Hajnoczi 写道:
> On Sat, Jun 08, 2013 at 02:58:02PM +0800, Wenchao Xia wrote:
>>   static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
>
> I suggest renaming the argument to make it less confusing: const char *name_or_id
>
   will rename it.

>>   {
>> -    BDRVQcowState *s = bs->opaque;
>> -    int i, ret;
>> +    int ret;
>>
>> -    ret = find_snapshot_by_id(bs, name);
>> +    ret = find_snapshot_by_id_and_name(bs, name, NULL);
>>       if (ret >= 0)
>>           return ret;
>
> Since you're touching the other lines in this function you could add {}.
>
  OK.

>> -    for(i = 0; i < s->nb_snapshots; i++) {
>> -        if (!strcmp(s->snapshots[i].name, name))
>> -            return i;
>> -    }
>> -    return -1;
>> +    return find_snapshot_by_id_and_name(bs, NULL, name);
>>   }
>>
>>   /* if no id is provided, a new one is constructed */
>> @@ -333,7 +347,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
>>       }
>>
>>       /* Check that the ID is unique */
>> -    if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) {
>> +    if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) {
>>           return -EEXIST;
>>       }
>>
>> @@ -530,15 +544,21 @@ fail:
>>       return ret;
>>   }
>>
>> -int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
>> +int qcow2_snapshot_delete(BlockDriverState *bs,
>> +                          const char *snapshot_id,
>> +                          const char *name,
>> +                          Error **errp)
>
> This patch will fail to compile.  You haven't changed the
> .bdrv_snapshot_delete() prototype.
>
> Please make sure every patch compiles.
>
   shouldn't following line in this patch changed the prototype?

--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -157,7 +157,10 @@ struct BlockDriver {
                                  QEMUSnapshotInfo *sn_info);
      int (*bdrv_snapshot_goto)(BlockDriverState *bs,
                                const char *snapshot_id);
-    int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char 
*snapshot_id);
+    int (*bdrv_snapshot_delete)(BlockDriverState *bs,
+                                const char *snapshot_id,
+                                const char *name,
+                                Error **errp);

   let me retry.

>>   {
>>       BDRVQcowState *s = bs->opaque;
>>       QCowSnapshot sn;
>>       int snapshot_index, ret;
>>
>>       /* Search the snapshot */
>> -    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
>> +    snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
>>       if (snapshot_index < 0) {
>> +        error_setg(errp,
>> +                   "Can't find a snapshot with ID %s and name %s",
>> +                   snapshot_id, name);
>
> Are both snapshot_id and name guaranteed to be non-NULL here?  It is
> dangerous to pass NULL strings to sprintf() functions.  IIRC some libc
> implementations will crash, others will print "(null)" like Linux.
>
   OK, will check it.


-- 
Best Regards

Wenchao Xia