On 20.02.2017 14:05, Kevin Wolf wrote:
> Am 20.02.2017 um 13:28 hat Max Reitz geschrieben:
>> On 13.02.2017 18:22, Kevin Wolf wrote:
>>> By default, don't allow another writer for block devices that are
>>> attached to a guest device. For the cases where this setup is intended
>>> (e.g. using a cluster filesystem on the disk), the new option can be
>>> used to allow it.
>>>
>>> This change affects only devices using DEFINE_BLOCK_PROPERTIES().
>>> Devices directly using DEFINE_PROP_DRIVE() still accept writers
>>> unconditionally.
>>>
>>> Signed-off-by: Kevin Wolf <kw...@redhat.com>
>>> ---
>>> hw/block/block.c | 14 ++++++------
>>> include/hw/block/block.h | 4 +++-
>>> tests/qemu-iotests/172.out | 53
>>> ++++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 64 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/hw/block/block.c b/hw/block/block.c
>>> index c3d3901..3c218eb 100644
>>> --- a/hw/block/block.c
>>> +++ b/hw/block/block.c
>>> @@ -56,7 +56,7 @@ void blkconf_apply_backend_options(BlockConf *conf, bool
>>> readonly,
>>> {
>>> BlockBackend *blk = conf->blk;
>>> BlockdevOnError rerror, werror;
>>> - uint64_t perm;
>>> + uint64_t perm, shared_perm;
>>> bool wce;
>>> int ret;
>>>
>>> @@ -65,11 +65,13 @@ void blkconf_apply_backend_options(BlockConf *conf,
>>> bool readonly,
>>> perm |= BLK_PERM_WRITE;
>>> }
>>>
>>> - /* TODO Remove BLK_PERM_WRITE unless explicitly configured so */
>>> - ret = blk_set_perm(blk, perm,
>>> - BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED
>>> |
>>> - BLK_PERM_GRAPH_MOD | BLK_PERM_RESIZE |
>>> BLK_PERM_WRITE,
>>> - errp);
>>> + shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
>>> + BLK_PERM_GRAPH_MOD | BLK_PERM_RESIZE;
>>
>> I'm not so sure BLK_PERM_RESIZE belongs here.
>
> Where does it belong in your opinion?Not unconditionally here, probably. > An option that I considered was adding BLK_PERM_RESIZE in > blk_set_dev_ops() if op.resize_cb != NULL, but it felt a bit too > implicit to me. > > Or I guess we can just add another bool parameter? It all depends on whether the device model can handle online resizes. I think a bool parameter would be fine. Max
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