On Mon, 05/19 22:23, Markus Armbruster wrote:
> Eric Blake <ebl...@redhat.com> writes:
>
> > On 05/11/2014 07:35 PM, Fam Zheng wrote:
> >> This makes use of op_blocker and blocks all the operations except for
> >> commit target, on each BlockDriverState->backing_hd.
> >>
> >> The asserts for op_blocker in bdrv_swap are removed because with this
> >> change, the target of block commit has at least the backing blocker of
> >> its child, so the assertion is not true. Callers should do their check.
> >>
> >> Signed-off-by: Fam Zheng <f...@redhat.com>
> >> ---
> >> block.c | 24 ++++++++++++++++++++----
> >> block/mirror.c | 1 +
> >> include/block/block_int.h | 3 +++
> >> 3 files changed, 24 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/block.c b/block.c
> >> index ec26a2b..8155e68 100644
> >> --- a/block.c
> >> +++ b/block.c
> >> @@ -1097,14 +1097,31 @@ fail:
> >> void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState
> >> *backing_hd)
> >> {
> >>
> >> + if (bs->backing_hd) {
> >> + assert(error_is_set(&bs->backing_blocker));
> >
> > error_is_set() is going away. Please don't use it.
> > https://lists.gnu.org/archive/html/qemu-devel/2014-05/msg03801.html
> >
> > This can just be assert(bs->backing_blocker).
>
> Yes. See commit 0fb6395. Another instance in PATCH 14.
Yes.
>
> >> + bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
> >> + } else if (backing_hd) {
> >> + error_setg(&bs->backing_blocker,
> >> + "device is used as backing hd of '%s'",
> >> + bs->device_name);
> >> + }
> >> +
> >> bs->backing_hd = backing_hd;
> >> if (!backing_hd) {
> >> + if (error_is_set(&bs->backing_blocker)) {
> >> + error_free(bs->backing_blocker);
> >
> > if (bs->backing_blocker) {
>
> Actually, unconditional error_free(bs->backing_blocker) is fine.
>
Thanks, will update.
Fam
