> From: Kevin Wolf [mailto:kw...@redhat.com] > Am 20.09.2019 um 09:25 hat Pavel Dovgalyuk geschrieben: > > > From: Kevin Wolf [mailto:kw...@redhat.com] > > > Am 19.09.2019 um 14:10 hat Pavel Dovgalyuk geschrieben: > > > > > From: Kevin Wolf [mailto:kw...@redhat.com] > > > > > diff --git a/block/block-backend.c b/block/block-backend.c > > > > > index 1c605d5444..c57d3d9fdf 100644 > > > > > --- a/block/block-backend.c > > > > > +++ b/block/block-backend.c > > > > > @@ -17,6 +17,7 @@ > > > > > #include "block/throttle-groups.h" > > > > > #include "hw/qdev-core.h" > > > > > #include "sysemu/blockdev.h" > > > > > +#include "sysemu/replay.h" > > > > > #include "sysemu/runstate.h" > > > > > #include "qapi/error.h" > > > > > #include "qapi/qapi-events-block.h" > > > > > @@ -808,6 +809,12 @@ void blk_remove_bs(BlockBackend *blk) > > > > > int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error > > > > > **errp) > > > > > { > > > > > ThrottleGroupMember *tgm = &blk->public.throttle_group_member; > > > > > + > > > > > + if (replay_mode != REPLAY_MODE_NONE && bs->drv != > > > > > &bdrv_blkreplay) { > > > > > + error_setg(errp, "Root node must be blkreplay"); > > > > > + return -ENOTSUP; > > > > > + } > > > > > > > > I guess this is opposite direction - bs->drv is bdrv_file. > > > > And we should check its parent. > > > > > > If bs->drv is bdrv_file, you want this to fail because only > > > bdrv_blkreplay should be able to be attached to devices. > > > > There was a regular rr invocation (as described in docs). > > And bs->drv always was a pointer to bdrv_file: for original image, > > and for temporary snapshot. > > Hm, what was the actual command line you used? I can see that you have a > separate -drive for the qcow2 file, so I can see how you get an unused > BlockBackend for the qcow2 node, but I don't see how it would be a file > node.
The command line was almost the same as in docs: -drive file=disk.img,format=raw,snapshot,id=img-direct \ -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \ -device virtio-blk-device,drive=img-blkreplay \ I've got the following blk_insert_bs invocations: 1. bs=ptr1 bs->drv=&bdrv_file, bs->filename=disk.img 2. bs=ptr2 bs->drv=&bdrv_file, bs->filename=<tmp filename> 3. bs=ptr2 bs->drv=&bdrv_file, bs->filename=<tmp filename> 4. bs=ptr2 bs->drv=&bdrv_file, bs->filename=<tmp filename> 5. bs=ptr3 bs->drv=&bdrv_file, bs->filename=<tmp filename> > Anyway, this leaves us two options: Either change the recommended > command line to use -blockdev for the qcow2 file so that no BlockBackend > is created for it (I think this might be preferable), or restrict the > error to when the BlockBackend is used. > > The second option would probably have to be done in blk_attach_dev(). > The problem with this is that the only expected error so far is that the > BlockBackend is already attached to a different device. So if you return > a new error there, you will have to touch its callers as well to have > this error correctly passed to the user. Pavel Dovgalyuk