Commit Graph

3 Commits

Author SHA1 Message Date
Fam Zheng
a1fbe750fd migration: Fix race of image locking between src and dst
Previously, dst side will immediately try to lock the write byte upon
receiving QEMU_VM_EOF, but at src side, bdrv_inactivate_all() is only
done after sending it. If the src host is under load, dst may fail to
acquire the lock due to racing with the src unlocking it.

Fix this by hoisting the bdrv_inactivate_all() operation before
QEMU_VM_EOF.

N.B. A further improvement could possibly be done to cleanly handover
locks between src and dst, so that there is no window where a third QEMU
could steal the locks and prevent src and dst from running.

N.B. This commit includes a minor improvement to the error handling
by using qemu_file_set_error().

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 20170616160658.32290-1-famz@redhat.com
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
[PMM: noted qemu_file_set_error() use in commit as suggested by Daniel]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-06-19 17:53:33 +01:00
Juan Quintela
c3d2e2e76c migration: Move constants to savevm.h
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
2017-06-13 11:00:45 +02:00
Juan Quintela
20a519a05a migration: Create savevm.h for functions exported from savevm.c
This removes last trace of migration functions from sysemu/sysemu.h.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
2017-05-31 09:39:19 +02:00