diff --git a/ocaml/xapi/context.ml b/ocaml/xapi/context.ml
index 92ab9c82130..7027caaec67 100644
--- a/ocaml/xapi/context.ml
+++ b/ocaml/xapi/context.ml
@@ -503,12 +503,23 @@ let get_user_agent context =
 let with_tracing ?originator ~__context name f =
   let open Tracing in
   let parent = __context.tracing in
-  let span_attributes = Attributes.attr_of_originator originator in
+  let span_attributes =
+    Attributes.attr_of_originator originator
+    @ make_attributes ~task_id:__context.task_id
+        ?session_id:__context.session_id ()
+  in
   match start_tracing_helper ~span_attributes (fun _ -> parent) name with
-  | Some _ as span ->
+  | Some _ as span -> (
+    try
       let new_context = {__context with tracing= span} in
       let result = f new_context in
       let _ = Tracer.finish span in
       result
+    with exn ->
+      let backtrace = Printexc.get_raw_backtrace () in
+      let error = (exn, Printexc.raw_backtrace_to_string backtrace) in
+      ignore @@ Tracer.finish span ~error ;
+      Printexc.raise_with_backtrace exn backtrace
+  )
   | None ->
       f __context
diff --git a/ocaml/xapi/helpers.ml b/ocaml/xapi/helpers.ml
index ba58ddd7b92..87e143dc227 100644
--- a/ocaml/xapi/helpers.ml
+++ b/ocaml/xapi/helpers.ml
@@ -546,6 +546,7 @@ let call_api_functions_internal ~__context f =
     )
 
 let call_api_functions ~__context f =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   match Context.get_test_rpc __context with
   | Some rpc ->
       f rpc (Ref.of_string "fake_session")
@@ -1733,6 +1734,7 @@ module Task : sig
 end = struct
   (* can't place these functions in task helpers due to circular dependencies *)
   let wait_for_ ~__context ~tasks ~propagate_cancel cb =
+    Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
     let our_task = Context.get_task_id __context in
     let classes =
       List.map
@@ -1819,6 +1821,7 @@ end = struct
     wait_for_ ~__context ~tasks:[t] mirror
 
   let to_result ~__context ~of_rpc ~t =
+    Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
     wait_for_mirror ~__context ~propagate_cancel:true ~t ;
     let fail msg =
       raise
diff --git a/ocaml/xapi/message_forwarding.ml b/ocaml/xapi/message_forwarding.ml
index 6be9f50d4c0..cef4de7a732 100644
--- a/ocaml/xapi/message_forwarding.ml
+++ b/ocaml/xapi/message_forwarding.ml
@@ -688,6 +688,7 @@ functor
       include Local.Task
 
       let cancel ~__context ~task =
+        Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
         TaskHelper.assert_op_valid ~__context task ;
         let local_fn = cancel ~task in
         let forwarded_to = Db.Task.get_forwarded_to ~__context ~self:task in
@@ -1185,6 +1186,7 @@ functor
         with _ -> ()
 
       let cancel ~__context ~vm ~ops =
+        Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
         let cancelled =
           List.filter_map
             (fun (task, op) ->
diff --git a/ocaml/xapi/taskHelper.ml b/ocaml/xapi/taskHelper.ml
index abe7f4b4599..e32c6bf811d 100644
--- a/ocaml/xapi/taskHelper.ml
+++ b/ocaml/xapi/taskHelper.ml
@@ -18,11 +18,19 @@ module Date = Xapi_stdext_date.Date
 
 let with_lock = Xapi_stdext_threads.Threadext.Mutex.execute
 
+let ( let@ ) f x = f x
+
+let finally_complete_tracing ?error __context f =
+  Xapi_stdext_pervasives.Pervasiveext.finally f (fun () ->
+      Context.complete_tracing ?error __context
+  )
+
 type t = API.ref_task
 
 (* creates a new task *)
 let make ~__context ~http_other_config ?(description = "") ?session_id
     ?subtask_of label : t * t Uuidx.t =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   let uuid = Uuidx.make () in
   let uuid_str = Uuidx.to_string uuid in
   let ref = Ref.make () in
@@ -35,8 +43,7 @@ let make ~__context ~http_other_config ?(description = "") ?session_id
         Ref.null
   in
   let (_ : unit) =
-    Db_actions.DB_Action.Task.create ~ref ~__context
-      ~created:(Date.of_float (Unix.time ()))
+    Db_actions.DB_Action.Task.create ~ref ~__context ~created:(Date.now ())
       ~finished:(Date.of_float 0.0) ~current_operations:[] ~_type:"<none/>"
       ~session:(Option.value ~default:Ref.null session_id)
       ~resident_on:!Xapi_globs.localhost_ref ~status:`pending ~result:""
@@ -54,6 +61,7 @@ let rbac_assert_permission_fn = ref None
 (* required to break dep-cycle with rbac.ml *)
 
 let assert_op_valid ?(ok_if_no_session_in_context = false) ~__context task_id =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   let assert_permission_task_op_any () =
     match !rbac_assert_permission_fn with
     | None ->
@@ -101,6 +109,7 @@ let assert_op_valid ?(ok_if_no_session_in_context = false) ~__context task_id =
         assert_permission_task_op_any ()
 
 let get_name ~__context =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   let task_id = Context.get_task_id __context in
   if Ref.is_dummy task_id then
     Ref.name_of_dummy task_id
@@ -108,6 +117,7 @@ let get_name ~__context =
     Db.Task.get_name_label ~__context ~self:task_id
 
 let destroy ~__context task_id =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   if not (Ref.is_dummy task_id) then (
     assert_op_valid ~ok_if_no_session_in_context:true ~__context task_id ;
     Db_actions.DB_Action.Task.destroy ~__context ~self:task_id
@@ -123,34 +133,36 @@ let init () =
   Context.__make_task := make
 
 let operate_on_db_task ~__context f =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   if Context.task_in_database __context then
     f (Context.get_task_id __context)
 
 let set_description ~__context value =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.set_name_description ~__context ~self ~value
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.set_name_description ~__context ~self ~value
 
 let add_to_other_config ~__context key value =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.remove_from_other_config ~__context ~self ~key ;
-      Db_actions.DB_Action.Task.add_to_other_config ~__context ~self ~key ~value
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.remove_from_other_config ~__context ~self ~key ;
+  Db_actions.DB_Action.Task.add_to_other_config ~__context ~self ~key ~value
 
 let set_progress ~__context value =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.set_progress ~__context ~self ~value
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.set_progress ~__context ~self ~value
 
 let set_external_pid ~__context pid =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.set_externalpid ~__context ~self
-        ~value:(Int64.of_int pid)
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.set_externalpid ~__context ~self
+    ~value:(Int64.of_int pid)
 
 let clear_external_pid ~__context = set_external_pid ~__context (-1)
 
 let set_result_on_task ~__context task_id result =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   match result with
   | None ->
       ()
@@ -160,7 +172,9 @@ let set_result_on_task ~__context task_id result =
 
 (** Only set the result without completing the task. Useful for vm import *)
 let set_result ~__context result =
-  operate_on_db_task ~__context (fun t -> set_result_on_task ~__context t result)
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  set_result_on_task ~__context self result
 
 let status_to_string = function
   | `pending ->
@@ -178,36 +192,36 @@ let status_is_completed task_status =
   task_status = `success || task_status = `failure || task_status = `cancelled
 
 let complete ~__context result =
-  Context.complete_tracing __context ;
-  operate_on_db_task ~__context (fun self ->
-      let status = Db_actions.DB_Action.Task.get_status ~__context ~self in
-      if status = `pending then (
-        Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
-          ~value:[] ;
-        Db_actions.DB_Action.Task.set_finished ~__context ~self
-          ~value:(Date.of_float (Unix.time ())) ;
-        Db_actions.DB_Action.Task.set_progress ~__context ~self ~value:1. ;
-        set_result_on_task ~__context self result ;
-        Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`success
-      ) else
-        debug "the status of %s is: %s; cannot set it to `success"
-          (Ref.really_pretty_and_small self)
-          (status_to_string status)
-  )
+  let@ () = finally_complete_tracing __context in
+  let@ self = operate_on_db_task ~__context in
+  let status = Db_actions.DB_Action.Task.get_status ~__context ~self in
+  match status with
+  | `pending ->
+      Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
+        ~value:[] ;
+      Db_actions.DB_Action.Task.set_finished ~__context ~self
+        ~value:(Date.now ()) ;
+      Db_actions.DB_Action.Task.set_progress ~__context ~self ~value:1. ;
+      set_result_on_task ~__context self result ;
+      Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`success
+  | _ ->
+      debug "the status of %s is: %s; cannot set it to `success"
+        (Ref.really_pretty_and_small self)
+        (status_to_string status)
 
 let set_cancellable ~__context =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
-        ~value:[`cancel]
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
+    ~value:[`cancel]
 
 let set_not_cancellable ~__context =
-  operate_on_db_task ~__context (fun self ->
-      Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
-        ~value:[]
-  )
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self ~value:[]
 
 let is_cancelling ~__context =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   Context.task_in_database __context
   &&
   let l =
@@ -217,21 +231,22 @@ let is_cancelling ~__context =
   List.exists (fun (_, x) -> x = `cancel) l
 
 let raise_cancelled ~__context =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   let task_id = Context.get_task_id __context in
   raise Api_errors.(Server_error (task_cancelled, [Ref.string_of task_id]))
 
 let exn_if_cancelling ~__context =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   if is_cancelling ~__context then
     raise_cancelled ~__context
 
 let cancel_this ~__context ~self =
-  Context.complete_tracing __context ;
+  let@ () = finally_complete_tracing __context in
   assert_op_valid ~__context self ;
   let status = Db_actions.DB_Action.Task.get_status ~__context ~self in
   if status = `pending then (
     Db_actions.DB_Action.Task.set_progress ~__context ~self ~value:1. ;
-    Db_actions.DB_Action.Task.set_finished ~__context ~self
-      ~value:(Date.of_float (Unix.time ())) ;
+    Db_actions.DB_Action.Task.set_finished ~__context ~self ~value:(Date.now ()) ;
     Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`cancelled ;
     Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self ~value:[]
   ) else
@@ -240,35 +255,40 @@ let cancel_this ~__context ~self =
       (status_to_string status)
 
 let cancel ~__context =
-  operate_on_db_task ~__context (fun self -> cancel_this ~__context ~self)
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
+  let@ self = operate_on_db_task ~__context in
+  cancel_this ~__context ~self
 
 let failed ~__context exn =
   let backtrace = Printexc.get_backtrace () in
-  Context.complete_tracing __context ~error:(exn, backtrace) ;
+  let@ () = finally_complete_tracing ~error:(exn, backtrace) __context in
   let code, params = ExnHelper.error_of_exn exn in
-  operate_on_db_task ~__context (fun self ->
-      let status = Db_actions.DB_Action.Task.get_status ~__context ~self in
-      if status = `pending then (
-        Db_actions.DB_Action.Task.set_progress ~__context ~self ~value:1. ;
-        Db_actions.DB_Action.Task.set_error_info ~__context ~self
-          ~value:(code :: params) ;
-        Db_actions.DB_Action.Task.set_backtrace ~__context ~self
-          ~value:(Sexplib.Sexp.to_string Backtrace.(sexp_of_t (get exn))) ;
-        Db_actions.DB_Action.Task.set_finished ~__context ~self
-          ~value:(Date.of_float (Unix.time ())) ;
-        Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
-          ~value:[] ;
-        if code = Api_errors.task_cancelled then
-          Db_actions.DB_Action.Task.set_status ~__context ~self
-            ~value:`cancelled
-        else
-          Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`failure
-      ) else
-        debug "the status of %s is %s; cannot set it to %s"
-          (Ref.really_pretty_and_small self)
-          (status_to_string status)
-          (if code = Api_errors.task_cancelled then "`cancelled" else "`failure")
-  )
+  let@ self = operate_on_db_task ~__context in
+  let status = Db_actions.DB_Action.Task.get_status ~__context ~self in
+  match status with
+  | `pending ->
+      Db_actions.DB_Action.Task.set_progress ~__context ~self ~value:1. ;
+      Db_actions.DB_Action.Task.set_error_info ~__context ~self
+        ~value:(code :: params) ;
+      Db_actions.DB_Action.Task.set_backtrace ~__context ~self
+        ~value:(Sexplib.Sexp.to_string Backtrace.(sexp_of_t (get exn))) ;
+      Db_actions.DB_Action.Task.set_finished ~__context ~self
+        ~value:(Date.now ()) ;
+      Db_actions.DB_Action.Task.set_allowed_operations ~__context ~self
+        ~value:[] ;
+      if code = Api_errors.task_cancelled then
+        Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`cancelled
+      else
+        Db_actions.DB_Action.Task.set_status ~__context ~self ~value:`failure
+  | _ ->
+      debug "the status of %s is %s; cannot set it to %s"
+        (Ref.really_pretty_and_small self)
+        (status_to_string status)
+        ( if code = Api_errors.task_cancelled then
+            "`cancelled"
+          else
+            "`failure"
+        )
 
 type id = Sm of string | Xenops of string * string
 
@@ -287,6 +307,7 @@ let task_to_id_exn task =
   with_lock task_tbl_m (fun () -> Hashtbl.find task_to_id_tbl task)
 
 let register_task __context ?(cancellable = true) id =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   let task = Context.get_task_id __context in
   with_lock task_tbl_m (fun () ->
       Hashtbl.replace id_to_task_tbl id task ;
@@ -302,6 +323,7 @@ let register_task __context ?(cancellable = true) id =
   ()
 
 let unregister_task __context id =
+  let@ __context = Context.with_tracing ~__context __FUNCTION__ in
   (* The rest of the XenAPI Task won't be cancellable *)
   set_not_cancellable ~__context ;
   with_lock task_tbl_m (fun () ->
diff --git a/ocaml/xapi/xapi_task.ml b/ocaml/xapi/xapi_task.ml
index 22016270fbc..aef42c01593 100644
--- a/ocaml/xapi/xapi_task.ml
+++ b/ocaml/xapi/xapi_task.ml
@@ -20,6 +20,7 @@ module D = Debug.Make (struct let name = "xapi_task" end)
 open D
 
 let create ~__context ~label ~description =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   (* This call will have a dummy task ID already but we need to make a fresh one *)
   let subtask_of = Context.get_task_id __context in
   let session_id =
@@ -34,6 +35,7 @@ let create ~__context ~label ~description =
   t
 
 let destroy ~__context ~self =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   if TaskHelper.status_is_completed (Db.Task.get_status ~__context ~self) then
     Db.Task.destroy ~__context ~self
@@ -42,6 +44,7 @@ let destroy ~__context ~self =
       ~value:`destroy
 
 let cancel ~__context ~task =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   let localhost = Helpers.get_localhost ~__context in
   let forwarded_to = Db.Task.get_forwarded_to ~__context ~self:task in
   if Db.is_valid_ref __context forwarded_to && localhost <> forwarded_to then
@@ -62,21 +65,26 @@ let cancel ~__context ~task =
     info "Task.cancel is falling back to polling"
 
 let set_status ~__context ~self ~value =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   Db.Task.set_status ~__context ~self ~value
 
 let set_progress ~__context ~self ~value =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   Db.Task.set_progress ~__context ~self ~value
 
 let set_result ~__context ~self ~value =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   Db.Task.set_result ~__context ~self ~value
 
 let set_error_info ~__context ~self ~value =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   Db.Task.set_error_info ~__context ~self ~value
 
 let set_resident_on ~__context ~self ~value =
+  Context.with_tracing ~__context __FUNCTION__ @@ fun __context ->
   TaskHelper.assert_op_valid ~__context self ;
   Db.Task.set_resident_on ~__context ~self ~value