The Wednesday 12 Feb 2014 à 20:49:18 (+0100), Benoît Canet wrote : > The Tuesday 11 Feb 2014 à 16:12:17 (+0800), Fam Zheng wrote : > > On Mon, 02/10 22:49, Benoît Canet wrote: > > > Take into account the fact that a block filter like quorum will be in > > > bs->file > > > while a regular block driver device is really on the top level. > > > > > > Signed-off-by: Benoit Canet <ben...@irqsave.net> > > > --- > > > block.c | 14 ++++++++------ > > > 1 file changed, 8 insertions(+), 6 deletions(-) > > > > > > diff --git a/block.c b/block.c > > > index 07ac50a..d04f535 100644 > > > --- a/block.c > > > +++ b/block.c > > > @@ -5400,14 +5400,16 @@ bool bdrv_is_first_non_filter(BlockDriverState > > > *candidate) > > > > > > /* walk down the bs forest recursively */ > > > QTAILQ_FOREACH(bs, &bdrv_states, device_list) { > > > - bool perm; > > > - > > > - if (!bs->file) { > > > - continue; > > > + bool perm = false; > > > + > > > + if (bs->file && > > > + bs->file->drv && > > > + bs->file->drv->authorizations[BS_IS_A_FILTER]) { > > > + perm = bdrv_recurse_is_first_non_filter(bs->file, candidate); > > > + } else if (bs == candidate) { > > > + perm = true; > > > } > > > > > > - perm = bdrv_recurse_is_first_non_filter(bs->file, candidate); > > > - > > > /* candidate is the first non filter */ > > > if (perm) { > > > return true; > > > > With this change, if the top level driver has ->file, its implementation of > > .bdrv_recurse_is_first_non_filter() is skipped and bs->file is the start > > point. > > > > So we have an implication that single child block drivers (that has ->file) > > doesn't need to, and shouldn't implement this operation, as commentted above > > bdrv_generic_is_first_non_filter. > > > > Tested that this patch fixes the external snapshot problem, but didn't test > > the "quorum as bs->file case". > > > > Thanks, > > > > Reviewed-by: Fam Zheng <f...@redhat.com> > > After extensive testing of all type of quorum instanciations and snapshots I > discovered that we are not done yet with this issue. > > When instantiating quorum from the command line the quorum driver is in > bs->file->drv. > When using QMP's blockdev_add at once or by using references the quorum driver > is in bs->drv. > > As a result this patch work in half the cases: regular file and command line > quorum but not when quorum is instantiated via QMP. > > I don't understand why the block layer have this irregular behavior regarding > quorum instantiation. > > What would be the best way to fix this ?
I have a pending resping of this patch which tests for the two cases as a workaround. Should I post it ? Best regards Benoît > > Best regards > > Benoît >