On Fri, May 19, 2017 at 02:43:26PM +0800, Peter Xu wrote: > This idea derives from the bug reported: > > https://bugzilla.redhat.com/show_bug.cgi?id=1439147 > > It is not a extremely critical bug, since as long as the user uses > libvirt to migrate, we won't have such an issue at all (we'll have > identical command line parameters for QEMU). However it can be an > severe one, since it caused data loss (source VM will quit assuming > that destination VM is good, while it is not). So it would be good we > fix it. Meanwhile, imho the return path may be used for other things > as well in the future. > > This series proposed a solution for the bug - let's enable return path > even for precopy when possible, then source can know whether dest is > good or not, then it can decide to do something better than quit. > > The series is marked as RFC for two reasons: > > One point for RFC is the idea in general that whether we would like to > enable return path for precopy. I see it okay since after all it's > optional (so it greatly reduces the chance that QEMU command line user > will lose the data, and this feature will be automatically off when we > are using e.g. "exec:" to migrate to a file). > > The other one point is that I converted MigrationState into a QObject > (actually a QDevice) to let migration codes benefits from some general > framework advantages. > > I got at least one positive feedback on each of the RFC elements > mentioned above, so dare I post this to public. Though I guess some > migration reviewers may be on PTO recently (I just know it :), I still > decided to post this out for a broader rfc review. > > Smoke test done, and of course I verified this series to fix the bug > mentioned. > > Please review. Thanks. > > Peter Xu (6): > io: only allow return path for socket typed > migration: isolate return path on src > migration: fix leak of src file on dst > migration: shut src return path unconditionally > migration: let MigrationState be an QObject > migration: enable return path for precopy > > include/hw/compat.h | 4 ++ > include/io/channel.h | 1 + > include/migration/migration.h | 27 ++++++++- > include/qemu/typedefs.h | 1 - > io/channel-socket.c | 1 + > migration/migration.c | 133 > +++++++++++++++++++++++++++++++----------- > migration/postcopy-ram.c | 1 - > migration/qemu-file-channel.c | 9 +++ > migration/trace-events | 4 +- > 9 files changed, 140 insertions(+), 41 deletions(-) > > -- > 2.7.4 >
CC Laurent as well. Sorry! -- Peter Xu
