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;
+ }
/* open will not fail even if no CD is inserted, so add O_NONBLOCK */
return raw_open_common(bs, filename, flags, O_NONBLOCK);
--
1.7.1.1
