Il 10/01/2014 19:07, Peter Lieven ha scritto:
>
>
>
> Von meinem iPad gesendet
>
> Am 10.01.2014 um 19:05 schrieb "Paolo Bonzini" <[email protected]>:
>
>> Il 10/01/2014 18:16, ronnie sahlberg ha scritto:
>>>
>>> There is a common exception though, for the case where you read past
>>> the end of file.
>>> So short reads should normally not happen. Unless QEMU or the guest
>>> sends a request to libnfs to read past the end of the file.
>>
>> Yes, this can happen in QEMU and the various drivers are careful to pad
>> with zeroes. It could perhaps be moved to block.c, but for now each
>> driver handles it separately.
>
> ok i will add this as well. however, i thought i had seen code for this in
> block.c already?,
No, it corresponds to this code in block/raw-posix.c:
static int aio_worker(void *arg)
{
RawPosixAIOData *aiocb = arg;
ssize_t ret = 0;
switch (aiocb->aio_type & QEMU_AIO_TYPE_MASK) {
case QEMU_AIO_READ:
ret = handle_aiocb_rw(aiocb);
if (ret >= 0 && ret < aiocb->aio_nbytes && aiocb->bs->growable) {
iov_memset(aiocb->aio_iov, aiocb->aio_niov, ret,
0, aiocb->aio_nbytes - ret);
ret = aiocb->aio_nbytes;
}
if (ret == aiocb->aio_nbytes) {
ret = 0;
} else if (ret >= 0 && ret < aiocb->aio_nbytes) {
ret = -EINVAL;
}
break;
Paolo
