On 02/07/2015 16:03, Paolo Bonzini wrote:
>
>
> On 02/07/2015 15:58, Laurent Vivier wrote:
>> Since any /dev entry can be treated as a raw disk image, it is worth
>> noting which devices can be accessed when and how. /dev/rdisk nodes are
>> character-special devices, but are "raw" in the BSD sense and force
>> block-aligned I/O. They are closer to the physical disk than the buffer
>> cache. /dev/disk nodes, on the other hand, are buffered block-special
>> devices and are used primarily by the kernel's filesystem code.
>
> So the right thing to do would not be just to set need_alignment, but to
> probe it like we do on Linux for BDRV_O_NO_CACHE.
>
> I'm okay with doing the simple thing, but it needs a comment for non-BSDers.
So, what we have to do, in our case, for MacOS X cdrom, is something like:
... GetBSDPath ...
...
if (flags & BDRV_O_NOCACHE) {
strcat(bsdPath, "r");
}
...
?
Laurent
