Am 18.07.2014 um 07:52 hat Liu Yuan geschrieben: > On Fri, Jul 18, 2014 at 11:11:31AM +0800, Fam Zheng wrote: > > On Thu, 07/17 19:50, Liu Yuan wrote: > > > - allow drive-mirror to create sprase mirror on images like qcow2 > > > - allow qemu-img map to work as expected on quorum driver > > > > > > Cc: Benoit Canet <ben...@irqsave.net> > > > Cc: Kevin Wolf <kw...@redhat.com> > > > Cc: Stefan Hajnoczi <stefa...@redhat.com> > > > Signed-off-by: Liu Yuan <namei.u...@gmail.com> > > > --- > > > block/quorum.c | 16 ++++++++++++++++ > > > 1 file changed, 16 insertions(+) > > > > > > diff --git a/block/quorum.c b/block/quorum.c > > > index ebf5c71..f0d0a98 100644 > > > --- a/block/quorum.c > > > +++ b/block/quorum.c > > > @@ -780,6 +780,21 @@ static coroutine_fn int > > > quorum_co_flush(BlockDriverState *bs) > > > return result; > > > } > > > > > > +static int64_t coroutine_fn quorum_co_get_block_status(BlockDriverState > > > *bs, > > > + int64_t > > > sector_num, > > > + int nb_sectors, > > > + int *pnum) > > > +{ > > > + BDRVQuorumState *s = bs->opaque; > > > + BlockDriverState *child_bs = s->bs[0]; > > > > Should we consider other children? > > > > No, other children are identical because we always do multiple sync writes > and at boot time we check the length.
But the basic assumption in quorum is that a single child isn't reliable and can fail. Otherwise, you wouldn't have to read from all of them and compare the results. Kevin