Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives

[Jes Sorensen <Jes.Sorensen@redhat.com>]

On 07/20/10 18:35, David S. Ahern wrote:
> On 07/20/10 10:09, Jes.Sorensen@redhat.com wrote:
>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>> index 291699f..1b840c4 100644
>> --- a/block/raw-posix.c
>> +++ b/block/raw-posix.c
>> @@ -1139,6 +1139,11 @@ static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)
>>      BDRVRawState *s = bs->opaque;
>>  
>>      s->type = FTYPE_CD;
>> +    if (flags & BDRV_O_NOCACHE) {
>> +        fprintf(stderr, "O_DIRECT (cache=none) for CDROM/DVD device (%s) "
>> +                "is unsupported\n", filename);
>> +        exit(1);
>> +    }
> 
> If a cdrom is added via the monitor this would abruptly terminate the VM
> - which is not good.

True, but this would only happen if the user explicitly marks it
cache=none which is not the default value for a new drive, so it would
be a corner case.

Cheers,
Jes