Merge pull request #114 from xapi-project/creation_time

xenvmd: Host.connect should be idempotent

Author: djs55

xenvmd/xenvmd.ml

@@ -253,58 +253,63 @@ module VolumeManager = struct
       let toLVM = toLVM name in
       let fromLVM = fromLVM name in
       let freeLVM = freeLVM name in
-      ( try
-	  Lwt.return (Lvm.Vg.LVs.find_by_name freeLVM (Vg_IO.metadata_of vg).Lvm.Vg.lvs).Lvm.Lv.id
-        with _ ->
-	  fail Xenvm_interface.HostNotCreated ) >>= fun freeLVMid ->
-      ( match Vg_IO.find vg toLVM with
-        | Some lv -> return lv
-        | None -> assert false ) >>= fun v ->
-      Vg_IO.Volume.connect v
-      >>= function
-      | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" toLVM))
-      | `Ok disk ->
-      ToLVM.attach ~name ~disk ()
-      >>= fun to_LVM ->
-      ToLVM.state to_LVM
-      >>= fun state ->
-      debug "ToLVM queue is currently %s" (match state with `Running -> "Running" | `Suspended -> "Suspended");
-      ToLVM.resume to_LVM
-      >>= fun () ->
-      ( match Vg_IO.find vg fromLVM with
-        | Some lv -> return lv
-        | None -> assert false ) >>= fun v ->
-      Vg_IO.Volume.connect v
-      >>= function
-      | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" fromLVM))
-      | `Ok disk ->
-      FromLVM.attach ~name ~disk ()
-      >>= fun (initial_state, from_LVM) ->
-      ( if initial_state = `Suspended then begin
-        debug "The FromLVM queue was already suspended: resending the free blocks";
-        ( match Vg_IO.find vg freeLVM with
-          | Some lv -> return lv
-          | None -> assert false ) >>= fun lv ->
-        let allocation = Lvm.Lv.to_allocation (Vg_IO.Volume.metadata_of lv) in
-        FromLVM.push from_LVM allocation
-        >>= fun pos ->
-        FromLVM.advance from_LVM pos
-        >>= fun () ->
-        debug "Free blocks pushed";
+      if List.mem_assoc name !to_LVMs then begin
+        info "Host-specific volumes (%s, %s, %s) already connected" toLVM fromLVM freeLVM;
         return ()
       end else begin
-        debug "The FromLVM queue was running: no need to resend the free blocks";
+        ( try
+            Lwt.return (Lvm.Vg.LVs.find_by_name freeLVM (Vg_IO.metadata_of vg).Lvm.Vg.lvs).Lvm.Lv.id
+          with _ ->
+            fail Xenvm_interface.HostNotCreated ) >>= fun freeLVMid ->
+        ( match Vg_IO.find vg toLVM with
+          | Some lv -> return lv
+          | None -> assert false ) >>= fun v ->
+        Vg_IO.Volume.connect v
+        >>= function
+        | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" toLVM))
+        | `Ok disk ->
+        ToLVM.attach ~name ~disk ()
+        >>= fun to_LVM ->
+        ToLVM.state to_LVM
+        >>= fun state ->
+        debug "ToLVM queue is currently %s" (match state with `Running -> "Running" | `Suspended -> "Suspended");
+        ToLVM.resume to_LVM
+        >>= fun () ->
+        ( match Vg_IO.find vg fromLVM with
+          | Some lv -> return lv
+          | None -> assert false ) >>= fun v ->
+        Vg_IO.Volume.connect v
+        >>= function
+        | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" fromLVM))
+        | `Ok disk ->
+        FromLVM.attach ~name ~disk ()
+        >>= fun (initial_state, from_LVM) ->
+        ( if initial_state = `Suspended then begin
+          debug "The FromLVM queue was already suspended: resending the free blocks";
+          ( match Vg_IO.find vg freeLVM with
+            | Some lv -> return lv
+            | None -> assert false ) >>= fun lv ->
+          let allocation = Lvm.Lv.to_allocation (Vg_IO.Volume.metadata_of lv) in
+          FromLVM.push from_LVM allocation
+          >>= fun pos ->
+          FromLVM.advance from_LVM pos
+          >>= fun () ->
+          debug "Free blocks pushed";
+          return ()
+        end else begin
+          debug "The FromLVM queue was running: no need to resend the free blocks";
+          return ()
+        end )
+        >>= fun () ->
+        debug "querying state";
+        FromLVM.state from_LVM
+        >>= fun state ->
+        debug "FromLVM queue is currently %s" (match state with `Running -> "Running" | `Suspended -> "Suspended");
+        to_LVMs := (name, to_LVM) :: !to_LVMs;
+        from_LVMs := (name, from_LVM) :: !from_LVMs;
+        free_LVs := (name, (freeLVM,freeLVMid)) :: !free_LVs;
         return ()
-      end )
-      >>= fun () ->
-      debug "querying state";
-      FromLVM.state from_LVM
-      >>= fun state ->
-      debug "FromLVM queue is currently %s" (match state with `Running -> "Running" | `Suspended -> "Suspended");
-      to_LVMs := (name, to_LVM) :: !to_LVMs;
-      from_LVMs := (name, from_LVM) :: !from_LVMs;
-      free_LVs := (name, (freeLVM,freeLVMid)) :: !free_LVs;
-      return ()
+      end
 
     (* Hold this mutex when actively flushing from the ToLVM queues *)
     let flush_m = Lwt_mutex.create ()