Re: [Qemu-devel] [PATCH v4 4/7] block: Add checks of blocker in block operations

[Fam Zheng <famz@redhat.com>]

On 2013年11月26日 01:15, Paolo Bonzini wrote:
> Il 22/11/2013 06:24, Fam Zheng ha scritto:
>> Before operate on a BlockDriverState, respective types are checked
>> against bs->op_blockers and it will error out if there's a blocker.
>
> How did you choose them?  I understand blocking change (and eject?), but
> not blocking set-io-throttle.
>
> In particular, this means that old in_use users, which did not block
> commands such as nbd-server-add, will now block it.
>

Right, I'll drop nbd, passwd and throttle checks.

Fam

>
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>> ---
>>   blockdev-nbd.c |  4 ++++
>>   blockdev.c     | 25 +++++++++++++++++++++++++
>>   2 files changed, 29 insertions(+)
>>
>> diff --git a/blockdev-nbd.c b/blockdev-nbd.c
>> index 922cf56..c49feae 100644
>> --- a/blockdev-nbd.c
>> +++ b/blockdev-nbd.c
>> @@ -92,6 +92,10 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_NBD_SERVER_ADD, errp)) {
>> +        return;
>> +    }
>> +
>>       if (!has_writable) {
>>           writable = false;
>>       }
>> diff --git a/blockdev.c b/blockdev.c
>> index eb55b74..1921d27 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -1001,6 +1001,11 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
>>           return NULL;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
>> +                           errp)) {
>> +        return NULL;
>> +    }
>> +
>>       ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
>>       if (error_is_set(&local_err)) {
>>           error_propagate(errp, local_err);
>> @@ -1098,6 +1103,10 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)) {
>> +        return;
>> +    }
>> +
>>       if (!bdrv_is_inserted(bs)) {
>>           error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
>>           return;
>> @@ -1485,6 +1494,10 @@ void qmp_block_passwd(const char *device, const char *password, Error **errp)
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_PASSWD, errp)) {
>> +        return;
>> +    }
>> +
>>       err = bdrv_set_key(bs, password);
>>       if (err == -EINVAL) {
>>           error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
>> @@ -1536,6 +1549,10 @@ void qmp_change_blockdev(const char *device, const char *filename,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
>> +        return;
>> +    }
>> +
>>       if (format) {
>>           drv = bdrv_find_whitelisted_format(format, bs->read_only);
>>           if (!drv) {
>> @@ -1586,6 +1603,10 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
>>           return;
>>       }
>>
>> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_SET_IO_THROTTLE, errp)) {
>> +        return;
>> +    }
>> +
>>       memset(&cfg, 0, sizeof(cfg));
>>       cfg.buckets[THROTTLE_BPS_TOTAL].avg = bps;
>>       cfg.buckets[THROTTLE_BPS_READ].avg  = bps_rd;
>> @@ -1684,6 +1705,10 @@ 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;
>>
>