On Wed 29 Aug 2018 01:39:10 PM CEST, Max Reitz wrote:
> On 2018-08-26 16:09, Alberto Garcia wrote:
>> 'discard' is one of the basic BlockdevOptions available for all
>> drivers, but it's silently ignored by bdrv_reopen_prepare/commit(), so
>> the user cannot change it and doesn't get an error explaining that it
>> can't be changed.
>>
>> This should update the discard setting, but does nothing:
>>
>> (qemu) qemu-io virtio0 "reopen -o discard=on"
>>
>> Since there's no reason why we shouldn't allow changing it and the
>> implementation is simple let's just do it.
>>
>> Signed-off-by: Alberto Garcia <be...@igalia.com>
>> ---
>> block.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/block.c b/block.c
>> index 804d557608..21f1eb9cd1 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -3178,6 +3178,15 @@ int bdrv_reopen_prepare(BDRVReopenState
>> *reopen_state, BlockReopenQueue *queue,
>>
>> update_flags_from_options(&reopen_state->flags, opts);
>>
>> + value = qemu_opt_get(opts, "discard");
>> + if (value != NULL) {
>> + if (bdrv_parse_discard_flags(value, &reopen_state->flags) != 0) {
>> + error_setg(errp, "Invalid discard option");
>> + ret = -EINVAL;
>> + goto error;
>> + }
>> + }
>> +
>> /* node-name and driver must be unchanged. Put them back into the
>> QDict, so
>> * that they are checked at the end of this function. */
>> value = qemu_opt_get(opts, "node-name");
>
> Hm. Why not just use the same "trick" here as in your last patch,
> i.e. use qemu_opt_get_del() above and then qemu_opts_to_qdict() to
> return all unhandled options to the QDict?
Sure, I could do that and therefore forbid changing all of these
options. But as I said in the commit message, there's no reason why we
should not allow changing them.
Berto
