Re: [Qemu-devel] [PATCH 19/27] block/parallels: implement incorrect close detection

["Denis V. Lunev" <den@openvz.org>]

On 10/03/15 17:38, Roman Kagan wrote:
> On Tue, Mar 10, 2015 at 11:51:13AM +0300, Denis V. Lunev wrote:
>> The software driver must set inuse field in Parallels header to
>> 0x746F6E59 when the image is opened in read-write mode. The presence of
>> this magic in the header on open forces image consistency check.
>>
>> There is an unfortunate trick here. We can not check for inuse in
>> parallels_check as this will happen too late. It is possible to do
>> that for simple check, but during the fix this would always report
>> an error as the image was opened in BDRV_O_RDWR mode. Thus we save
>> the flag in BDRVParallelsState for this.
>>
>> On the other hand, nothing should be done to clear inuse in
>> parallels_check. Generic close will do the job right.
>>
>> Signed-off-by: Denis V. Lunev <den@openvz.org>
>> CC: Roman Kagan <rkagan@parallels.com>
>> CC: Kevin Wolf <kwolf@redhat.com>
>> CC: Stefan Hajnoczi <stefanha@redhat.com>
>> ---
>>   block/parallels.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 50 insertions(+)
>> @@ -462,6 +487,25 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
>>       }
>>       s->bat_bitmap = (uint32_t *)(s->header + 1);
>>   
>> +    if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
>> +        /* Image was not closed correctly. The check is mandatory */
>> +        s->header_unclean = true;
>> +        if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
>> +            error_setg(errp, "parallels: Image was not closed correctly; "
>> +                       "cannot be opened read/write");
>> +            ret = -EACCES;
> -EBUSY?
>
> Otherwise looks ok.
>
> Roman.
error code is the same as one in qcow2