Am 20.07.2010 17:17, schrieb jes.soren...@redhat.com: > 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. > > 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..0ea79b6 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, "Disabling unsupported O_DIRECT (cache=none) for " > + "CDROM/DVD device (%s)\n", filename); > + flags &= ~BDRV_O_NOCACHE; > + }
Good point. Just one detail: We should probably change bs->open_flags, too, to keep things consistent. Kevin