This reverts commit 64e69e8092. The commit
returned immediately from iscsi_aio_cancel, risking corruption in case the
following happens:
guest qemu target
=========================================================================
send write 1 -------->
send write 1 -------->
cancel write 1 ------>
cancel write 1 ------>
<------------------ cancellation processed
send write 2 -------->
send write 2 -------->
<---------------- completed write 2
<------------------ completed write 2
<---------------- completed write 1
<---------------- cancellation not done
Here, the guest would see write 2 superseding write 1, when in fact the
outcome could have been the opposite. The right behavior is to return
only after the target says whether the cancellation was done or not, and
it will be implemented by the next three patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>