* Peter Xu (pet...@redhat.com) wrote: > We used to have quite a few places making sure -EIO happened and that's the > only way to trigger postcopy recovery. That's based on the assumption that > we'll only return -EIO for channel issues. > > It'll work in 99.99% cases but logically that won't cover some corner cases. > One example is e.g. ram_block_from_stream() could fail with an interrupted > network, then -EINVAL will be returned instead of -EIO. > > I remembered Dave Gilbert pointed that out before, but somehow this is > overlooked. Neither did I encounter anything outside the -EIO error. > > However we'd better touch that up before it triggers a rare VM data loss > during > live migrating. > > To cover as much those cases as possible, remove the -EIO restriction on > triggering the postcopy recovery, because even if it's not a channel failure, > we can't do anything better than halting QEMU anyway - the corpse of the > process may even be used by a good hand to dig out useful memory regions, or > the admin could simply kill the process later on. > > Signed-off-by: Peter Xu <pet...@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > --- > migration/migration.c | 4 ++-- > migration/postcopy-ram.c | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 6e4cc9cc87..67520d3105 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -2877,7 +2877,7 @@ retry: > out: > res = qemu_file_get_error(rp); > if (res) { > - if (res == -EIO && migration_in_postcopy()) { > + if (res && migration_in_postcopy()) { > /* > * Maybe there is something we can do: it looks like a > * network down issue, and we pause for a recovery. > @@ -3478,7 +3478,7 @@ static MigThrError > migration_detect_error(MigrationState *s) > error_free(local_error); > } > > - if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret == -EIO) { > + if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret) { > /* > * For postcopy, we allow the network to be down for a > * while. After that, it can be continued by a > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index d3ec22e6de..6be510fea4 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -1038,7 +1038,7 @@ retry: > msg.arg.pagefault.address); > if (ret) { > /* May be network failure, try to wait for recovery */ > - if (ret == -EIO && postcopy_pause_fault_thread(mis)) { > + if (postcopy_pause_fault_thread(mis)) { > /* We got reconnected somehow, try to continue */ > goto retry; > } else { > -- > 2.32.0 > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK