From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=34364 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ObFo8-00084v-5X for qemu-devel@nongnu.org; Tue, 20 Jul 2010 12:36:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1ObFmk-0002o2-AZ for qemu-devel@nongnu.org; Tue, 20 Jul 2010 12:35:15 -0400 Received: from sj-iport-1.cisco.com ([171.71.176.70]:8136) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1ObFmk-0002nl-2i for qemu-devel@nongnu.org; Tue, 20 Jul 2010 12:35:14 -0400 Message-ID: <4C45D03E.3090706@cisco.com> Date: Tue, 20 Jul 2010 10:35:10 -0600 From: "David S. Ahern" MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] Error on O_DIRECT for physical CDROM/DVD drives References: <1279642177-21229-1-git-send-email-Jes.Sorensen@redhat.com> In-Reply-To: <1279642177-21229-1-git-send-email-Jes.Sorensen@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jes.Sorensen@redhat.com Cc: qemu-devel@nongnu.org On 07/20/10 10:09, Jes.Sorensen@redhat.com wrote: > From: Jes Sorensen > > 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 > --- > 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);