Re: [Qemu-devel] [PATCH v2 02/23] block: New BlockBackend

[Markus Armbruster]

Markus Armbruster <address@hidden> writes:

> Benoît Canet <address@hidden> writes:
>
>>> --- a/block.c
>>> +++ b/block.c
>>> @@ -2119,10 +2119,11 @@ static void bdrv_delete(BlockDriverState *bs)
>>>  
>>>      bdrv_close(bs);
>>>  
>>
>>
>>> +    drive_info_del(drive_get_by_blockdev(bs));
>>> +
>>>      /* remove from list, if necessary */
>>>      bdrv_make_anon(bs);
>>>  
>>> -    drive_info_del(drive_get_by_blockdev(bs));
>>
>> Do we really want this move ?
>
> Yes, we do.  If bdrv_make_anon() runs before drive_info_del(), this
> conditional in drive_info_del() is always false:
>
>     if (dinfo->bdrv->device_name[0]) {
>         blk_unref(blk_by_name(dinfo->bdrv->device_name));
>     }
>
> I apologize for the hairiness.  Things will become *way* simpler in
> PATCH 4.

It's not just temporarily hairy, it's temporarily wrong: double unref is
possible.

drive_del, the gift that keeps on giving...

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