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Date: Thu, 28 Nov 2013 11:39:00 +0800
From: Fam Zheng <famz@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v5 4/7] block: Add checks of blocker in
	block operations
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, hbrock@redhat.com, qemu-devel@nongnu.org, rjones@redhat.com, imain@redhat.com, stefanha@redhat.com

On 2013=E5=B9=B411=E6=9C=8827=E6=97=A5 00:13, Paolo Bonzini wrote:
> Il 26/11/2013 05:05, Fam Zheng ha scritto:
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -1001,6 +1001,11 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_inte=
rnal_sync(const char *device,
>>           return NULL;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE=
,
>> +                           errp)) {
>> +        return NULL;
>> +    }
>
> Why not check in bdrv_snapshot_delete...
>
>>       ret =3D bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &lo=
cal_err);
>>       if (error_is_set(&local_err)) {
>>           error_propagate(errp, local_err);
>> @@ -1098,6 +1103,10 @@ static void internal_snapshot_prepare(BlkTransa=
ctionState *common,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)=
) {
>> +        return;
>> +    }
>
> ... and bdrv_snapshot_create?
>

OK.

>>       if (!bdrv_is_inserted(bs)) {
>>           error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
>>           return;
>> @@ -1536,6 +1545,10 @@ void qmp_change_blockdev(const char *device, co=
nst char *filename,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
>> +        return;
>> +    }
>> +
>>       if (format) {
>>           drv =3D bdrv_find_whitelisted_format(format, bs->read_only);
>>           if (!drv) {
>> @@ -1684,6 +1697,10 @@ void qmp_block_resize(const char *device, int64=
_t size, Error **errp)
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_RESIZE, errp)) {
>> +        return;
>> +    }
>> +
>>       if (size < 0) {
>>           error_set(errp, QERR_INVALID_PARAMETER_VALUE, "size", "a >0 =
size");
>>           return;
>> --
>
> This should be redundant since bdrv_truncate already checks.
>

It doesn't hurt and skips bdrv_drain_all if op is blocked.

Fam