On 07/20/10 10:09, jes.soren...@redhat.com wrote:
> From: Jes Sorensen <jes.soren...@redhat.com>
>
> O_DIRECT (cache=none) requires sector alignment, however the physical
> sector size of CDROM/DVD drives is 2048, as opposed to most disk
> devices which use 512. QEMU is hard coding 512 all over the place, so
> allowing O_DIRECT for CDROM/DVD devices does not work. Exit with an
> error!
>
> Signed-off-by: Jes Sorensen <jes.soren...@redhat.com>
> ---
> block/raw-posix.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> 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.
David
>
> /* open will not fail even if no CD is inserted, so add O_NONBLOCK */
> return raw_open_common(bs, filename, flags, O_NONBLOCK);
