Remove GuestWorkId (2/2) (#1482)

(staged on top of #1481)

`GuestWorkId` is always 1:1 with `JobId`, so let's get rid of it!

It's not exposed to the guest or used by anything outside of Crucible
internals.

The only exception is DTrace probes, which now use the `JobId`
everywhere (instead of a mix of `JobId` and `GuestWorkId`). The
`gw__*__start` probes now fire immediately after a `JobId` is assigned,
rather than when the `GuestWorkId` was assigned.

upstairs/src/client.rs

@@ -1376,13 +1376,12 @@ impl DownstairsClient {
  "[{}] read hash mismatch on id {}\n\
  Expected {:x?}\n\
  Computed {:x?}\n\
- guest_id:{} start eid:{:?} start offset:{:?}\n\
+ start eid:{:?} start offset:{:?}\n\
  job state:{:?}",
  self.client_id,
  ds_id,
  job.read_validations,
  read_validations,
- job.guest_id,
  start_eid,
  start_offset,
  job.state,
@@ -1433,7 +1432,7 @@ impl DownstairsClient {
  assert!(!job.acked);
  ackable = true;
  debug!(self.log, "Read AckReady {}", ds_id.0);
- cdt::up__to__ds__read__done!(|| job.guest_id.0);
+ cdt::up__to__ds__read__done!(|| ds_id.0);
  } else {
  /*
  * If another job has finished already, we can
@@ -1465,7 +1464,7 @@ impl DownstairsClient {
  assert!(extent_info.is_none());
  if jobs_completed_ok == 2 {
  ackable = true;
- cdt::up__to__ds__write__done!(|| job.guest_id.0);
+ cdt::up__to__ds__write__done!(|| ds_id.0);
  }
  }
  IOop::WriteUnwritten { .. } => {
@@ -1474,9 +1473,7 @@ impl DownstairsClient {
  assert!(extent_info.is_none());
  if jobs_completed_ok == 2 {
  ackable = true;
- cdt::up__to__ds__write__unwritten__done!(|| job
- .guest_id
- .0);
+ cdt::up__to__ds__write__unwritten__done!(|| ds_id.0);
  }
  }
  IOop::Flush {
@@ -1502,7 +1499,7 @@ impl DownstairsClient {
 
  if jobs_completed_ok == ack_at_num_jobs {
  ackable = true;
- cdt::up__to__ds__flush__done!(|| job.guest_id.0);
+ cdt::up__to__ds__flush__done!(|| ds_id.0);
  if deactivate {
  debug!(self.log, "deactivate flush {ds_id} done");
  }